JP2016156669A - Sensor element, force detection device and robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor element, a force detection device and a robot having excellent detection accuracy.SOLUTION: The sensor element of the present invention includes a first piezoelectric plate, a second piezoelectric plate layered in a thickness direction of the first piezoelectric plate on the first piezoelectric plate, and a first joint layer laminating the first piezoelectric plate and the second piezoelectric plate, in which an end of the first joint layer has a portion overlapping neither an end of the first piezoelectric plate nor an end of the second piezoelectric plate when viewed in the thickness direction. The sensor element has a side electrode disposed on a side face parallel to the thickness direction, in which the end of the first joint layer is spaced from the side electrode.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sensor element, a force detection device, and a robot.

  In recent years, industrial robots have been introduced into production facilities such as factories for the purpose of improving production efficiency. Such an industrial robot includes an arm that can be driven in the direction of one axis or a plurality of axes, and an end effector such as a hand, a component inspection instrument, or a component transfer instrument that is attached to the tip of the arm. Parts manufacturing work such as parts assembly work, parts processing work, parts transport work, parts inspection work, etc. can be executed.

  In such an industrial robot, a force detection device having a sensor element is provided between the arm and the end effector. The sensor element of this force detection device has a laminate composed of a plurality of piezoelectric plates and a plurality of internal electrodes provided therebetween. In addition, the laminate is generally formed by forming internal electrodes on one surface of each piezoelectric plate, joining them with a joining layer, and laminating them. As a result, it is possible to obtain a sensor element in which a piezoelectric plate, an internal electrode, and an adhesive layer are stacked in order. The internal electrode functions as a ground electrode that is grounded to the ground (reference potential point) or an output electrode that outputs charges (current) generated in the piezoelectric plate. And the side electrode connected to the said output electrode and the side electrode connected to the said ground electrode are provided in the side surface of the laminated body.

  Patent Document 1 discloses a piezoelectric device (laminated body) in which a piezoelectric sheet and internal electrodes are bonded together by an adhesive layer and these are laminated. When viewed from the stacking direction of the piezoelectric sheet and the internal electrode, the adhesive layer has the same shape and the same dimensions as the piezoelectric sheet. Such a piezoelectric device can be applied to a sensor element of a force detection device, for example.

JP 2012-204423 A

  When the piezoelectric device described in Patent Document 1 is applied to the sensor element of the force detection device, the adhesive layer has the same shape and the same dimensions as the piezoelectric sheet when viewed from the stacking direction. It becomes the structure which contacted the side electrode. For this reason, even if the internal electrode is configured not to contact the side electrode where current is not desired to flow, a leak current is generated in the side electrode where current is not desired to flow through the adhesive layer, and the detection accuracy is reduced. is there.

  An object of the present invention is to provide a sensor element, a force detection device, and a robot having excellent detection accuracy.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A sensor element according to the present invention includes a first piezoelectric plate,
A second piezoelectric plate laminated with the first piezoelectric plate in the thickness direction of the first piezoelectric plate;
A first bonding layer that laminates the first piezoelectric plate and the second piezoelectric plate;
When viewed from the thickness direction, the end portion of the first bonding layer has a portion that does not overlap the end portion of the first piezoelectric plate and the end portion of the second piezoelectric plate.

  Thereby, the leakage current generated through the first bonding layer can be suppressed, and the detection accuracy can be improved.

[Application Example 2]
In the sensor element according to the present invention, when viewed from the thickness direction, the end portion of the first bonding layer may not overlap either the end portion of the first piezoelectric plate or the end portion of the second piezoelectric plate. preferable.

  Thereby, the leakage current generated through the first bonding layer can be suppressed, and the detection accuracy can be improved.

[Application Example 3]
The sensor element according to the present invention has a side electrode provided on a side surface parallel to the thickness direction,
It is preferable that an end portion of the first bonding layer and the side electrode are separated from each other.

  Thereby, a signal can be output via the side electrode, and a leak current flowing through the side electrode via the first bonding layer can be suppressed.

[Application Example 4]
The sensor element according to the present invention has an internal electrode provided on either the main surface intersecting the thickness direction of the first piezoelectric plate or the main surface intersecting the thickness direction of the second piezoelectric plate,
As viewed from the thickness direction, the first bonding layer preferably overlaps the internal electrode.

  Accordingly, a signal can be output through the internal electrode, and the first piezoelectric plate and the second piezoelectric plate can be firmly bonded by the first bonding layer.

[Application Example 5]
In the sensor element according to the present invention, it is preferable that the sensor element includes a second bonding layer provided at an end portion of the first piezoelectric plate and the second piezoelectric plate and spaced apart from the first bonding layer.

  Accordingly, the bonding strength between the first piezoelectric plate and the second piezoelectric plate can be improved, the reliability can be improved, and the leakage current generated through the second bonding layer can be suppressed. it can.

[Application Example 6]
The sensor element according to the present invention has an internal electrode provided on either the main surface intersecting the thickness direction of the first piezoelectric plate or the main surface intersecting the thickness direction of the second piezoelectric plate,
It is preferable that the second bonding layer and the internal electrode are separated from each other.

  As a result, a signal can be output through the internal electrode, and a leakage current generated through the second bonding layer can be suppressed.

[Application Example 7]
A force detection device according to the present invention is a force detection device including a force sensor element,
The force sensor element includes a first piezoelectric plate,
A second piezoelectric plate laminated with the first piezoelectric plate in the thickness direction of the first piezoelectric plate;
A first bonding layer that laminates the first piezoelectric plate and the second piezoelectric plate;
When viewed from the thickness direction, the end portion of the first bonding layer has a portion that does not overlap the end portion of the first piezoelectric plate and the end portion of the second piezoelectric plate.

  Thereby, the leakage current generated through the first bonding layer can be suppressed, and the detection accuracy can be improved.

[Application Example 8]
In the force detection device according to the present invention, when viewed from the thickness direction, the end portion of the first bonding layer does not overlap either the end portion of the first piezoelectric plate or the end portion of the second piezoelectric plate. Is preferred.

  Thereby, the leakage current generated through the first bonding layer can be suppressed, and the detection accuracy can be improved.

[Application Example 9]
The force detection device according to the present invention has a side electrode provided on a side surface parallel to the thickness direction,
It is preferable that an end portion of the first bonding layer and the side electrode are separated from each other.

  Thereby, a signal can be output via the side electrode, and a leak current flowing through the side electrode via the first bonding layer can be suppressed.

[Application Example 10]
The force detection device according to the present invention includes an internal electrode provided on either the main surface intersecting the thickness direction of the first piezoelectric plate or the main surface intersecting the thickness direction of the second piezoelectric plate. ,
In view of the thickness, it is preferable that the first bonding layer overlaps the internal electrode.

  Accordingly, a signal can be output through the internal electrode, and the first piezoelectric plate and the second piezoelectric plate can be firmly bonded by the first bonding layer.

[Application Example 11]
In the force detection device according to the present invention, it is preferable to have a second bonding layer provided at an end of the first piezoelectric plate and the second piezoelectric plate and spaced from the first bonding layer.

  Accordingly, the bonding strength between the first piezoelectric plate and the second piezoelectric plate can be improved, the reliability can be improved, and the leakage current generated through the second bonding layer can be suppressed. it can.

[Application Example 12]
The force detection device according to the present invention includes an internal electrode provided on either the main surface intersecting the thickness direction of the first piezoelectric plate or the main surface intersecting the thickness direction of the second piezoelectric plate. ,
It is preferable that the second bonding layer and the internal electrode are separated from each other.

  As a result, a signal can be output through the internal electrode, and a leakage current generated through the second bonding layer can be suppressed.

[Application Example 13]
A robot according to the present invention includes an arm,
An end effector provided on the arm;
A force detection device that is provided between the arm and the end effector and detects an external force applied to the end effector,
The force detection device includes a force sensor element,
The force sensor element includes a first piezoelectric plate,
A second piezoelectric plate laminated with the first piezoelectric plate in the thickness direction of the first piezoelectric plate;
A first bonding layer that laminates the first piezoelectric plate and the second piezoelectric plate;
When viewed from the thickness direction, the end portion of the first bonding layer has a portion that does not overlap the end portion of the first piezoelectric plate and the end portion of the second piezoelectric plate.

  Thereby, the leakage current generated through the first bonding layer can be suppressed, and the detection accuracy can be improved.

[Application Example 14]
In the robot according to the present invention, it is preferable that the end portion of the first bonding layer does not overlap either the end portion of the first piezoelectric plate or the end portion of the second piezoelectric plate when viewed from the thickness direction. .

  Thereby, the leakage current generated through the first bonding layer can be suppressed, and the detection accuracy can be improved.

[Application Example 15]
The robot according to the present invention has a side electrode provided on a side surface parallel to the thickness direction,
It is preferable that an end portion of the first bonding layer and the side electrode are separated from each other.

  Thereby, a signal can be output via the side electrode, and a leak current flowing through the side electrode via the first bonding layer can be suppressed.

[Application Example 16]
The robot according to the present invention has an internal electrode provided on either the main surface intersecting the thickness direction of the first piezoelectric plate or the main surface intersecting the thickness direction of the second piezoelectric plate,
In view of the thickness, it is preferable that the first bonding layer overlaps the internal electrode.

  Accordingly, a signal can be output through the internal electrode, and the first piezoelectric plate and the second piezoelectric plate can be firmly bonded by the first bonding layer.

[Application Example 17]
In the robot according to the present invention, it is preferable that the robot has a second bonding layer that is provided at end portions of the first piezoelectric plate and the second piezoelectric plate and is separated from the first bonding layer.

  Accordingly, the bonding strength between the first piezoelectric plate and the second piezoelectric plate can be improved, the reliability can be improved, and the leakage current generated through the second bonding layer can be suppressed. it can.

[Application Example 18]
The robot according to the present invention has an internal electrode provided on either the main surface intersecting the thickness direction of the first piezoelectric plate or the main surface intersecting the thickness direction of the second piezoelectric plate,
It is preferable that the second bonding layer and the internal electrode are separated from each other.

  As a result, a signal can be output through the internal electrode, and a leakage current generated through the second bonding layer can be suppressed.

It is sectional drawing which shows 1st Embodiment of the force detection apparatus of this invention. It is sectional drawing of the force detection apparatus shown in FIG. It is a top view which shows roughly the electric charge output element of the force detection apparatus shown in FIG. FIG. 4 is a cross-sectional view schematically showing a charge output element of the force detection device shown in FIG. 1 (cross-sectional view taken along the line AA in FIG. 3). It is sectional drawing (sectional drawing in the BB line in FIG. 3) which shows schematically the electric charge output element of the force detection apparatus shown in FIG. It is sectional drawing which shows schematically the electric charge output element in 2nd Embodiment of the force detection apparatus of this invention. It is sectional drawing which shows schematically the electric charge output element in 2nd Embodiment of the force detection apparatus of this invention. It is a figure which shows an example of the single arm robot using the force detection apparatus of this invention. It is a figure which shows an example of the multi-arm robot using the force detection apparatus of this invention.

  Hereinafter, a sensor element, a force detection device, and a robot of the present invention are explained in detail based on a suitable embodiment shown in an accompanying drawing.

<First Embodiment of Force Detection Device>
FIG. 1 is a cross-sectional view showing a first embodiment of the force detection device of the present invention. FIG. 2 is a cross-sectional view of the force detection device shown in FIG. FIG. 3 is a plan view schematically showing a charge output element of the force detection device shown in FIG. 4 is a cross-sectional view schematically showing a charge output element of the force detection device shown in FIG. 1 (a cross-sectional view taken along line AA in FIG. 3). FIG. 5 is a cross-sectional view (cross-sectional view taken along line BB in FIG. 3) schematically showing the charge output element of the force detection device shown in FIG.

  In the following, the upper side in FIG. 1 is referred to as “upper” or “upper”, and the lower side is referred to as “lower” or “lower”. For the charge output element, the upper side in FIGS. 4 and 5 is referred to as “upper” or “upper”, and the lower side is referred to as “lower” or “lower”. These are the same in the second embodiment.

  FIG. 2 shows an α axis, a β axis, and a γ axis as three axes orthogonal to each other. Further, FIGS. 1, 3, 4 and 5 show only the γ-axis among the three axes. The direction parallel to the α (A) axis is “α (A) axis direction” or “α direction”, and the direction parallel to the β (B) axis is “β (B) axis direction” or “β direction”, γ ( C) A direction parallel to the axis is referred to as “γ (C) axis direction” or “γ direction”. A plane defined by the α axis and the β axis is referred to as an “αβ plane”, a plane defined by the β axis and the γ axis is referred to as a “βγ plane”, and a plane defined by the α axis and the γ axis is referred to as “ It is called “αγ plane”. In the α direction, β direction, and γ direction, the arrow tip side is defined as “+ (positive) side” and the arrow base end side is defined as “− (negative) side”. These are the same in the second embodiment.

  The force detection device 1 shown in FIG. 1 has an external force applied to the force detection device 1, that is, a six-axis force (a translational force component in the α, β, and γ axis directions and a rotational force component around the α, β, and γ axes). It has a function to detect.

  The force detection device 1 includes a first base (first member) 2, a second base (first member) 3 that is disposed at a predetermined interval from the first base 2 and faces the first base 2, Four analog circuit boards 4 housed (provided) between the first base 2 and the second base 3, and housed (provided) between the first base 2 and the second base 3, A digital circuit board 5 electrically connected to the analog circuit board 4 and a charge output element (sensor) which is mounted on each analog circuit board 4 and outputs a signal (charge) according to the received external force. Element) (force sensor element) 10 and four sensor devices (pressure detecting part) 6 having a package (accommodating part) 60 for accommodating charge output element 10, and eight pressurizing bolts (fixing member) 71. ing.

Below, the structure of each part of the force detection apparatus 1 is explained in full detail.
In the following description, as shown in FIG. 2, among the four sensor devices 6, the sensor device 6 located on the right side in FIG. 2 is referred to as “sensor device 6 </ b> A”, and hereinafter “sensor” in order counterclockwise. These are referred to as “device 6B”, “sensor device 6C”, and “sensor device 6D”. When the sensor devices 6A, 6B, 6C, and 6D are not distinguished, they are referred to as “sensor device 6”.

  As shown in FIG. 1, the first base (base plate) 2 has a plate shape, and its planar shape (a shape seen from the thickness direction) has a rounded square shape. In addition, the planar shape of the 1st base 2 is not limited to the thing of illustration, For example, other polygons, such as a pentagon and a hexagon, circle, an ellipse, etc. are mentioned.

  For example, when the force detection device 1 is provided between a robot arm and an end effector and is used as a force sensor for detecting an external force applied to the end effector, the lower surface 221 of the first base 2 is It functions as an attachment surface (first attachment surface) for the arm (object).

  The first base portion 2 includes a bottom plate 22 and a wall portion 24 erected upward from the bottom plate 22.

  The wall portion 24 has an “L” shape, and a convex portion 23 is formed on each of two surfaces facing outward. The top surface (first surface) 231 of each convex portion 23 is a plane perpendicular to the bottom plate 22. Moreover, the convex part 23 is provided with the internal thread 241 screwed together with the pressurizing bolt 71 mentioned later (refer FIG. 2).

  As shown in FIG. 1, a second base (cover plate) 3 is arranged so as to face the first base 2 with a predetermined interval.

  Similarly to the first base 2, the second base 3 has a plate shape. Further, the planar shape of the second base 3 is preferably a shape corresponding to the planar shape of the first base 2, and in this embodiment, the planar shape of the second base 3 is the same as the planar shape of the first base 2. Similarly, it has a rounded square. The second base 3 is preferably the same size as the first base 2 or a size that includes the first base 2.

  Taking the case where the force detection device 1 is used as a force sensor for the robot as an example, the upper surface (second surface) 321 of the second base 3 is attached to an end effector (object) attached to the arm of the robot. It functions as a surface (second mounting surface). Further, the upper surface 321 of the second base 3 and the lower surface 221 of the first base 2 described above are parallel in a natural state where no external force is applied.

  The second base 3 includes a top plate 32 and four side walls 33 that are formed at the edge of the top plate 32 and project downward from the edge. The inner wall surface (second surface) 331 of each side wall 33 is a plane perpendicular to the top plate 32. The sensor device 6 is provided between the top surface 231 of the first base 2 and the inner wall surface 331 of each side wall 33 of the second base 3.

  The first base 2 and the second base 3 are connected and fixed by a pressurizing bolt 71. As shown in FIG. 2, there are eight (a plurality) of the pressurizing bolts 71, and two of them are arranged on both sides of each sensor device 6. The number of pressurizing bolts 71 for one sensor device 6 is not limited to two, and may be three or more, for example.

  Moreover, it does not specifically limit as a constituent material of the pressurization volt | bolt 71, For example, various resin materials, various metal materials, etc. can be used.

  Thus, the first base 2 and the second base 3 connected by the pressurizing bolt 71 form a storage space for storing the sensor devices 6A to 6D, the analog circuit board 4, and the digital circuit board 5. The storage space has a circular or rounded square cross-sectional shape.

  As shown in FIG. 1, an analog circuit board 4 that is electrically connected to the sensor device 6 is provided between the first base 2 and the second base 3.

  In the portion of the analog circuit board 4 where the sensor device 6 (specifically, the charge output element 10) is disposed, a hole 41 into which each convex portion 23 of the first base 2 is inserted is formed. The hole 41 is a through hole that penetrates the analog circuit board 4.

  Further, as shown in FIG. 2, the analog circuit board 4 is provided with a through hole through which each pressurizing bolt 71 passes, and a portion (through hole) of the analog circuit board 4 through which the pressurizing bolt 71 passes is provided. A pipe 43 made of an insulating material such as a resin material is fixed by fitting, for example.

  Further, as shown in FIG. 1, each analog circuit is located between the first base 2 and the second base 3 at a position different from the position where each analog circuit board 4 is provided on the first base 2. A digital circuit board 5 electrically connected to the board 4 is provided. The digital circuit board 5 is disposed so as to be parallel to the bottom plate 22 of the first base 2 and the top plate 32 of the second base 3. The position in the thickness direction of the first base portion 2 and the second base portion 3 of the digital circuit board 5 is not particularly limited as long as it is between the first base portion 2 and the second base portion 3. For example, as shown in FIG. Thus, the vicinity of the 2nd base 3 may be sufficient, the vicinity of the 1st base 2 may be sufficient, and the middle position (center part) of the 1st base 2 and the 2nd base 3 may be sufficient.

  Moreover, although the 1st base 2 and the 2nd base 3 are each comprised by the member which makes plate shape, it is not limited to this, For example, one base part is comprised by the member which makes plate shape, and the other The base may be composed of a block-shaped member.

Next, the sensor device 6 will be described.
[Sensor device]
As shown in FIGS. 1 and 2, the sensor device 6 </ b> A includes a top surface 231 of one convex portion 23 among the four convex portions 23 of the first base 2, and an inner wall surface 331 facing the top surface 231. It is pinched by. Similar to the sensor device 6A, the sensor device 6B is sandwiched between the top surface 231 of one convex portion 23 different from the above and the inner wall surface 331 facing the top surface 231. Further, the sensor device 6C is sandwiched between the top surface 231 of one convex portion 23 different from the above and the inner wall surface 331 facing the top surface 231. Further, the sensor device 6D is sandwiched between the top surface 231 of one convex portion 23 different from the above and the inner wall surface 331 facing the top surface 231.

  In the following, the direction in which the sensor devices 6A to 6D are sandwiched between the first base 2 and the second base 3 is referred to as “clamping direction SD”. Further, among the sensor devices 6A to 6D, the direction in which the sensor device 6A is clamped is the first clamping direction, the direction in which the sensor device 6B is clamped is the second clamping direction, and the direction in which the sensor device 6C is clamped. The third clamping direction and the direction in which the sensor device 6D is clamped may be referred to as a fourth clamping direction.

  In this embodiment, as shown in FIG. 1, the sensor device 6 is provided on the second base 3 (side wall 33) side of the analog circuit board 4, but the sensor device 6 is provided on the analog circuit board 4. It may be provided on the first base 2 side.

  As shown in FIG. 2, the sensor device 6 </ b> A and the sensor device 6 </ b> B and the sensor device 6 </ b> C and the sensor device 6 </ b> D are disposed symmetrically with respect to the central axis 271 along the β axis of the first base 2. That is, the sensor devices 6 </ b> A to 6 </ b> D are arranged at equiangular intervals around the center 272 of the first base 2. By arranging the sensor devices 6A to 6D in this way, it is possible to detect the external force without bias.

  The arrangement of the sensor devices 6A to 6D is not limited to that shown in the drawing, but the sensor devices 6A to 6D are as far as possible from the center (center 272) of the second base 3 when viewed from the upper surface 321 of the second base 3. It is preferable that they are arranged at spaced positions. Thereby, the external force applied to the force detection apparatus 1 can be detected stably.

  Moreover, in this embodiment, although sensor device 6A-6D is mounted in the state which all faced the same direction, direction of sensor device 6A-6D may each differ.

  As shown in FIG. 1, the sensor device 6 arranged in this manner includes a charge output element 10 and a package 60 that houses the charge output element 10. In the present embodiment, the sensor devices 6A to 6D have the same configuration. Note that the package may be omitted.

Hereinafter, the charge output element 10 provided in the sensor device 6 will be described.
[Charge output element (sensor element)]
The charge output element 10 has a function of outputting a charge according to an external force applied to the force detection device 1, that is, an external force applied to at least one base of the first base 2 or the second base 3.

  In addition, since each charge output element 10 with which the sensor devices 6A-6D are provided has the same configuration, one charge output element 10 will be mainly described.

  As shown in FIG. 4, the charge output element 10 included in the sensor device 6 is arranged with a first cover base material 161 and a predetermined distance from the first cover base material 161, and the first cover base material 161. 161 includes a second cover base material 162 that faces 161, a stacked body 110 that outputs electric charge, and side electrodes 171, 172, 173, and 174 that are electrically connected to the stacked body 110. The stacked body 110 is sandwiched between the first cover base material 161 and the second cover base material 162.

  As shown in FIG. 4, the 1st cover base material 161, the laminated body 110, and the 2nd cover base material 162 are laminated | stacked in parallel in this order toward the upper direction in FIG. Further, the first cover base material 161 and the second cover base material 162 are each made of an insulating material and have a function of blocking conduction between the package 60 and the stacked body 110.

  In addition, as shown in FIG. 3, the shapes of the first cover base material 161 and the second cover base material 162 are not particularly limited. When viewed from a direction perpendicular to the wall surface 331, it is rectangular. In addition, as another shape at the time of seeing from the said direction of the 1st cover base material 161 and the 2nd cover base material 162, for example, other polygons, such as a pentagon and a hexagon, circle, ellipse, respectively Examples include shapes.

  As shown in FIGS. 3 to 5, the laminated body 110 described later has four side surfaces 110a, 110b, 110c, and 110d, and the side electrodes 171, 172, 173, and 174 have side surfaces, respectively. 110a, 110b, 110c and 110d. Note that the side surfaces 110a, 110b, 110c, and 110d are each parallel to a laminating direction LD described later.

  The side electrodes 171 to 174 are electrically connected to corresponding output terminals (not shown) provided on the package 60, respectively.

  Moreover, although the material which comprises the side electrodes 171-174 is not specifically limited, For example, gold | metal | money, titanium, aluminum, copper, iron, or an alloy containing these is preferable. Among these, it is particularly preferable to use stainless steel which is an iron alloy. The side electrodes 171 to 174 made of stainless steel have excellent durability and corrosion resistance.

  In addition, the shape of the stacked body 110 is not particularly limited, but in the present embodiment, the first cover base material 161 and the second cover base material are viewed from a direction perpendicular to the inner wall surface 331 of each side wall 33. It has the same shape as 162, that is, a quadrangle. In addition, as another shape at the time of seeing from the said direction of the laminated body 110, other polygons, such as a pentagon and a hexagon, circle, an ellipse, etc. are mentioned, for example.

  4 and 5, the laminate 110 includes six ground electrode layers (internal electrodes) 111, 112, 113, 114, 115 and 116 grounded to the ground (reference potential point), 1 sensor 12, second sensor 13, and third sensor 14. The ground electrode layer 111, the first sensor 12, the ground electrode layers 112 and 113, the second sensor 13, the ground electrode layers 114 and 115, the third sensor 14 and the ground electrode layer 116 face upward in FIG. In this order, they are stacked in parallel. Hereinafter, this stacked direction is referred to as “stacked direction LD”. In addition, the stacking direction and the thickness direction of each layer constituting the first sensor 12, the second sensor 13, and the third sensor 14 are also the same as the stacking direction LD. This is referred to as “stacking direction LD”. The stacking direction LD is perpendicular to the normal line NL2 of the upper surface 321 (or the normal line NL1 of the lower surface 221) (see FIG. 1). Further, the stacking direction LD is parallel to the sandwiching direction SD (see FIG. 1). Note that the stacking order of the first sensor 12, the second sensor 13, and the third sensor 14 is arbitrary, and in the present invention, the first sensor 12, the second sensor 13, and the third sensor shown in FIG. The order of stacking the sensors 14 is not limited.

  The first sensor 12 has a function of outputting a charge Qx according to an external force (shearing force). The second sensor 13 has a function of outputting a charge Qz according to an external force (compression / tensile force). The third sensor 14 outputs a charge Qy according to an external force (shearing force).

  Hereinafter, the ground electrode layers 111 to 116, the first sensor 12, the second sensor 13, and the third sensor 14 will be described.

  Only one of the four sides of each of the ground electrode layers 111 to 116 is located on the side surface 110 b of the multilayer body 110. The ground electrode layers 111 to 116 are in contact with and electrically connected to only the side electrode 172 of the side electrodes 171 to 174, respectively, and are grounded to the ground (reference potential point) via the side electrode 172. Electrode.

  The ground electrode layer 111 and the first cover base material 161 are bonded (laminated) by the first bonding layer 151. The first bonding layer 151 is disposed between the first cover base 161 and the first piezoelectric layer 121, and the ground electrode layer 111 is formed between the first piezoelectric layer 121 and the first bonding layer. 151.

  Further, the ground electrode layer 112 and the ground electrode layer 113 are joined by the first joining layer 152. The first bonding layer 152 is disposed between the second piezoelectric layer 123 and the third piezoelectric layer 131, and the ground electrode layer 112 is formed of the second piezoelectric layer 123 and the first bonding layer. The ground electrode layer 113 is disposed between the third piezoelectric layer 131 and the first bonding layer 152.

  In addition, the ground electrode layer 114 and the ground electrode layer 115 are bonded by the first bonding layer 153. The first bonding layer 153 is disposed between the fourth piezoelectric layer 133 and the fifth piezoelectric layer 141, and the ground electrode layer 114 is formed between the fourth piezoelectric layer 133 and the first bonding layer. The ground electrode layer 115 is disposed between the fifth piezoelectric layer 141 and the first bonding layer 153.

  In addition, the ground electrode layer 116 and the second cover base material 162 are joined by the first joining layer 154. The first bonding layer 154 is disposed between the second cover base material 162 and the sixth piezoelectric layer 143, and the ground electrode layer 116 is formed of the sixth piezoelectric layer 143 and the first bonding layer. 154. The first bonding layers 151 to 154 will be described in detail later.

  Moreover, although the material which comprises the ground electrode layers 111-116 is not specifically limited, For example, gold | metal | money, titanium, aluminum, copper, iron, or an alloy containing these is preferable. Among these, it is particularly preferable to use stainless steel which is an iron alloy. The ground electrode layers 111 to 116 made of stainless steel have excellent durability and corrosion resistance.

  The first sensor 12 is in response to an external force (shearing force) in the first detection direction orthogonal to the stacking direction LD (first clamping direction), that is, in the same direction as the direction of the normal line NL2 (normal line NL1). It has a function of outputting charge Qx. That is, the first sensor 12 is configured to output a positive charge or a negative charge according to an external force. Note that an x-axis direction in a first piezoelectric layer 121 and a second piezoelectric layer 123 described later is the first detection direction.

  The first sensor 12 is provided on the upper surface of the first piezoelectric layer 121, the second piezoelectric layer 123 provided to face the first piezoelectric layer 121, and the first piezoelectric layer 121. The first output electrode layer (internal electrode) 124 and the second output electrode layer (internal electrode) 125 provided on the lower surface of the second piezoelectric layer 123 are provided. Further, the first output electrode layer 124 and the second output electrode layer 125 are joined by a first joining layer 126. The first bonding layer 126 is disposed between the first piezoelectric layer 121 and the second piezoelectric layer 123, and the first output electrode layer 124 is formed between the first piezoelectric layer 121 and the first piezoelectric layer 121. The second output electrode layer 125 is disposed between the first bonding layer 126 and the second output electrode layer 125 is disposed between the second piezoelectric layer 123 and the first bonding layer 126. The first bonding layer 126 will be described in detail later.

  The first piezoelectric layer 121 is composed of a Y-cut quartz plate and has an x-axis, a y-axis, and a z-axis that are crystal axes orthogonal to each other. The y axis is an axis along the thickness direction of the first piezoelectric layer 121, the x axis is an axis along the depth direction in FIG. 4, and the z axis is the left-right direction in FIG. Axis along.

  In the following description, it is assumed that the tip side of each of the illustrated arrows is “+ (positive)” and the base end side is “− (negative)”. A direction parallel to the x axis is referred to as an “x axis direction”, a direction parallel to the y axis is referred to as a “y axis direction”, and a direction parallel to the z axis is referred to as a “z axis direction”. The same applies to a second piezoelectric layer 123, a third piezoelectric layer 131, a fourth piezoelectric layer 133, a fifth piezoelectric layer 141, and a sixth piezoelectric layer 143 described later.

  The second piezoelectric layer 123 is also composed of a Y-cut quartz plate and has an x-axis, a y-axis, and a z-axis that are crystal axes orthogonal to each other. The y-axis is an axis along the thickness direction of the second piezoelectric layer 123, the x-axis is an axis along the depth direction in FIG. 4, and the z-axis is the left-right direction in FIG. Axis along.

  The first output electrode layer 124 has a function of outputting a positive charge or a negative charge generated in the first piezoelectric layer 121, and the second output electrode layer 125 is in the second piezoelectric layer 123. Has a function of outputting a positive charge or a negative charge generated in. Each of the first output electrode layer 124 and the second output electrode layer 125 has only one of the four sides positioned on the side surface 110a of the stacked body 110, and the side surfaces of the side electrodes 171 to 174. It contacts only the electrode 171 and is electrically connected. As a result, the charge Qx formed by adding the positive charge or negative charge generated in the first piezoelectric layer 121 and the positive charge or negative charge generated in the second piezoelectric layer 123 becomes the side electrode 171. Is output from.

  The second sensor 13 has a function of outputting a charge Qz according to an external force (compression / tensile force). That is, the second sensor 13 is configured to output a positive charge according to the compressive force and output a negative charge according to the tensile force. Note that the x-axis direction in a third piezoelectric layer 131 and a fourth piezoelectric layer 133, which will be described later, is the direction of the compression and tensile force detected.

  The second sensor 13 is provided on the upper surface of the third piezoelectric layer 131, the fourth piezoelectric layer 133 provided to face the third piezoelectric layer 131, and the third piezoelectric layer 131. The third output electrode layer (internal electrode) 134 and the fourth output electrode layer (internal electrode) 135 provided on the lower surface of the fourth piezoelectric layer 133 are provided. Further, the third output electrode layer 134 and the fourth output electrode layer 135 are bonded by the first bonding layer 136. The first bonding layer 136 is disposed between the third piezoelectric layer 131 and the fourth piezoelectric layer 133, and the third output electrode layer 134 is connected to the third piezoelectric layer 131 and the third piezoelectric layer 131. The fourth output electrode layer 135 is disposed between the first bonding layer 136 and the fourth output electrode layer 135 is disposed between the fourth piezoelectric layer 133 and the first bonding layer 136. The first bonding layer 136 will be described in detail later.

  The third piezoelectric layer 131 is composed of an X-cut quartz plate and has an x axis, a y axis, and a z axis that are orthogonal to each other. The x-axis is an axis along the thickness direction of the third piezoelectric layer 131, the y-axis is an axis along the left-right direction in FIG. 4, and the z-axis is the depth direction in the drawing of FIG. Axis along.

  The fourth piezoelectric layer 133 is also composed of an X-cut quartz plate and has an x-axis, a y-axis, and a z-axis that are orthogonal to each other. The x-axis is the axis along the thickness direction of the fourth piezoelectric layer 133, the y-axis is the axis along the left-right direction in FIG. 4, and the z-axis is the depth direction of the page in FIG. Axis along.

  The third output electrode layer 134 has a function of outputting positive charges or negative charges generated in the third piezoelectric layer 131, and the fourth output electrode layer 135 is in the fourth piezoelectric layer 133. Has a function of outputting a positive charge or a negative charge generated in. Each of the third output electrode layer 134 and the fourth output electrode layer 135 has only one of the four sides thereof positioned on the side surface 110d of the multilayer body 110, and the side surfaces of the side surface electrodes 171 to 174. It contacts only the electrode 174 and is electrically connected. As a result, the charge Qz formed by adding the positive charge or negative charge generated in the third piezoelectric layer 131 and the positive charge or negative charge generated in the fourth piezoelectric layer 133 is the side electrode 174. Is output from.

  The third sensor 14 is perpendicular to the stacking direction LD (second clamping direction), and intersects (orthogonal) the first detection direction of the external force acting when the first sensor 12 outputs the electric charge Qx. It has a function of outputting the charge Qx according to the external force (shearing force) in the detection direction. That is, the third sensor 14 is configured to output a positive charge or a negative charge according to an external force. Note that an x-axis direction in a fifth piezoelectric layer 141 and a sixth piezoelectric layer 143 described later is the second detection direction.

  The third sensor 14 includes a fifth piezoelectric layer (second detection plate) 141, a sixth piezoelectric layer (second detection plate) 143 provided to face the fifth piezoelectric layer 141, and The fifth output electrode layer (internal electrode) 144 provided on the upper surface of the fifth piezoelectric layer 141 and the sixth output electrode layer (internal electrode) provided on the lower surface of the sixth piezoelectric layer 143 145. Further, the fifth output electrode layer 144 and the sixth output electrode layer 145 are joined by the first joining layer 146. The first bonding layer 146 is disposed between the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143, and the fifth output electrode layer 144 is connected to the fifth piezoelectric layer 141 and the fifth piezoelectric layer 141. The sixth output electrode layer 145 is disposed between the first bonding layer 146 and the sixth output electrode layer 145 is disposed between the sixth piezoelectric layer 143 and the first bonding layer 146. The first bonding layer 146 will be described in detail later.

  The fifth piezoelectric layer 141 is composed of a Y-cut quartz plate and has an x-axis, a y-axis, and a z-axis that are crystal axes orthogonal to each other. The y-axis is an axis along the thickness direction of the fifth piezoelectric layer 141, the x-axis is an axis along the left-right direction in FIG. 4, and the z-axis is the depth direction in the drawing of FIG. Axis along.

  The sixth piezoelectric layer 143 is also composed of a Y-cut quartz plate and has an x axis, a y axis, and a z axis, which are crystal axes orthogonal to each other. The y-axis is an axis along the thickness direction of the sixth piezoelectric layer 143, the x-axis is an axis along the left-right direction in FIG. 4, and the z-axis is the depth direction of the page in FIG. Axis along.

  In the charge output element 10, the x-axis of the first piezoelectric layer 121 and the second piezoelectric layer 123, and the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143 when viewed from the stacking direction LD. The x-axis of each intersects. Further, when viewed from the stacking direction LD, each z axis of the first piezoelectric layer 121 and the second piezoelectric layer 123, and each z axis of the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143. And intersect.

  The fifth output electrode layer 144 has a function of outputting a positive charge or a negative charge generated in the fifth piezoelectric layer 141, and the sixth output electrode layer 145 is in the sixth piezoelectric layer 143. Has a function of outputting a positive charge or a negative charge generated in. Each of the fifth output electrode layer 144 and the sixth output electrode layer 145 has only one of the four sides positioned on the side surface 110c of the multilayer body 110, and the side surfaces of the side electrodes 171 to 174. It contacts only the electrode 173 and is electrically connected. As a result, the charge Qy formed by adding the positive charge or negative charge generated in the fifth piezoelectric layer 141 and the positive charge or negative charge generated in the sixth piezoelectric layer 143 becomes the side electrode 173. Is output from.

  Note that the first output electrode layer 124, the second output electrode layer 125, the third output electrode layer 134, the fourth output electrode layer 135, the fifth output electrode layer 144, and the sixth output electrode layer 145 are provided. Although the material which comprises is not specifically limited, For example, gold | metal | money, titanium, aluminum, copper, iron, or an alloy containing these is preferable. Among these, it is particularly preferable to use stainless steel which is an iron alloy. The output electrode layers 124, 125, 134, 135, 144 and 145 made of stainless steel have excellent durability and corrosion resistance.

  In addition, each of the first bonding layers 126, 136, 146, 151 to 154 has an insulating property, that is, is configured of an insulating material (insulator). As a constituent material of each of the first bonding layers 126, 136, 146, 151 to 154, for example, an adhesive such as silicone, epoxy, acrylic, cyanoacrylate, polyurethane, or the like is used, for example. it can.

  As described above, in the charge output element 10, the first sensor 12, the second sensor 13, and the third sensor 14 are stacked so that the force detection directions of the sensors are orthogonal to each other. Thereby, each sensor can induce an electric charge according to force components orthogonal to each other. Therefore, the charge output element 10 can output three charges Qx, Qy, and Qz according to each external force along the x axis, the y axis, and the z axis.

  Further, as described above, the charge output element 10 can output the charge Qz, but the force detection device 1 preferably does not use the charge Qz when obtaining each external force. That is, the force detection device 1 is preferably used as a device that detects a shearing force without detecting compression or tensile force. Thereby, the noise component resulting from the temperature change of the force detection apparatus 1 can be reduced. The charge Qz is used, for example, for adjusting the pressurization by the pressurization bolt 71 even when not being used when obtaining each external force.

In the present embodiment, the piezoelectric layers described above (the first piezoelectric layer 121, the second piezoelectric layer 123, the third piezoelectric layer 131, the fourth piezoelectric layer 133, and the fifth piezoelectric layer). The body layer 141 and the sixth piezoelectric layer 143) are all configured using quartz, but each piezoelectric layer may be configured using a piezoelectric material other than quartz. Examples of piezoelectric materials other than quartz include topaz, barium titanate, lead titanate, lead zirconate titanate (PZT: Pb (Zr, Ti) O ₃ ), lithium niobate, lithium tantalate, and the like. However, each piezoelectric layer preferably has a configuration using quartz. This is because the piezoelectric layer made of quartz has excellent characteristics such as a wide dynamic range, high rigidity, high natural frequency, and high load resistance.

  In the present embodiment, the number of piezoelectric layers of the first sensor 12, the second sensor 13, and the third sensor 14 is two, but is not limited to this, for example, one. Also good.

Hereinafter, the first bonding layers 126, 136, 146, and 151 to 154 will be described.
In the present embodiment, the following members (parts) of the first piezoelectric plate and the second piezoelectric plate according to the present invention correspond to the first piezoelectric plate and the second piezoelectric plate.

  That is, one of the first piezoelectric layer 121 and the second piezoelectric layer 123 corresponds to the first piezoelectric plate, and the other corresponds to the second piezoelectric plate. One of the third piezoelectric layer 131 and the fourth piezoelectric layer 133 corresponds to the first piezoelectric plate, and the other corresponds to the second piezoelectric plate. One of the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143 corresponds to the first piezoelectric plate, and the other corresponds to the second piezoelectric plate. One of the second piezoelectric layer 123 and the third piezoelectric layer 131 corresponds to the first piezoelectric plate, and the other corresponds to the second piezoelectric plate. One of the fourth piezoelectric layer 133 and the fifth piezoelectric layer 141 corresponds to the first piezoelectric plate, and the other corresponds to the second piezoelectric plate.

  Also, the upper surface of the first piezoelectric layer 121, the lower surface of the second piezoelectric layer 123, the upper surface of the third piezoelectric layer 131, the lower surface of the fourth piezoelectric layer 133, and the fifth piezoelectric layer 141 The upper surface and the lower surface of the sixth piezoelectric layer 143 correspond to main surfaces that are orthogonal to (intersect) the stacking direction LD, respectively.

  As shown in FIGS. 4 and 5, the end of the first bonding layer 126 overlaps the end of the first piezoelectric layer 121 and the end of the second piezoelectric layer 123 as viewed from the stacking direction LD. It has a part that must not be. In the present embodiment, when viewed from the stacking direction LD, the end portion of the first bonding layer 126 does not overlap either the end portion of the first piezoelectric layer 121 or the end portion of the second piezoelectric layer 123. . That is, the outer peripheral surface (end portion) of the first bonding layer 126 is disposed on the inner side of the side surfaces 110a, 110b, 110c, and 110d of the multilayer body 110 over the entire circumference of the outer periphery. 174. As a result, leakage current generated through the first bonding layer 126, that is, leakage current flowing through the side bonding electrodes 172, 173, and 174 through the first bonding layer 126 can be suppressed, and detection accuracy can be improved. Can do.

  The same applies to the other first bonding layers 136, 146, 151, 152, 153, and 154.

  That is, as viewed from the stacking direction LD, the end of the first bonding layer 136 has a portion that does not overlap the end of the third piezoelectric layer 131 and the end of the fourth piezoelectric layer 133. In the present embodiment, when viewed from the stacking direction LD, the end of the first bonding layer 136 does not overlap either the end of the third piezoelectric layer 131 or the end of the fourth piezoelectric layer 133. . That is, the outer peripheral surface (end portion) of the first bonding layer 136 is disposed on the inner side of the side surfaces 110a, 110b, 110c, and 110d of the multilayer body 110 over one circumference of the outer periphery, and the side electrodes 171- 174. Thereby, the leakage current generated through the first bonding layer 136, that is, the leakage current flowing through the side electrodes 171, 172 and 173 through the first bonding layer 136 can be suppressed, and the detection accuracy can be improved. Can do.

  Further, when viewed from the stacking direction LD, the end portion of the first bonding layer 146 has a portion that does not overlap the end portion of the fifth piezoelectric layer 141 and the end portion of the sixth piezoelectric layer 143. In the present embodiment, when viewed from the stacking direction LD, the end portion of the first bonding layer 146 does not overlap either the end portion of the fifth piezoelectric layer 141 or the end portion of the sixth piezoelectric layer 143. . That is, the outer peripheral surface (end portion) of the first bonding layer 146 is disposed on the inner side of the side surfaces 110a, 110b, 110c, and 110d of the multilayer body 110 over the entire circumference of the outer periphery. 174. Thereby, the leakage current generated through the first bonding layer 146, that is, the leakage current flowing through the side electrodes 171 172, and 174 through the first bonding layer 146 can be suppressed, and detection accuracy can be improved. Can do.

  Further, when viewed from the stacking direction LD, the end portion of the first bonding layer 151 has a portion that does not overlap the end portion of the first cover base material 161 and the end portion of the first piezoelectric layer 121. In the present embodiment, when viewed from the stacking direction LD, the end portion of the first bonding layer 151 does not overlap either the end portion of the first cover base material 161 or the end portion of the first piezoelectric layer 121. . That is, the outer peripheral surface (end portion) of the first bonding layer 151 is disposed on the inner side of the side surfaces 110a, 110b, 110c, and 110d of the stacked body 110 over one circumference of the outer periphery, and the side electrodes 171- 174. Thereby, the leakage current generated through the first bonding layer 151, that is, the leakage current flowing through the side electrodes 171 173, and 174 through the first bonding layer 151 can be suppressed, and detection accuracy is improved. Can do.

  Further, when viewed from the stacking direction LD, the end portion of the first bonding layer 152 has a portion that does not overlap the end portion of the second piezoelectric layer 123 and the end portion of the third piezoelectric layer 131. In the present embodiment, when viewed from the stacking direction LD, the end portion of the first bonding layer 152 does not overlap either the end portion of the second piezoelectric layer 123 or the end portion of the third piezoelectric layer 131. . That is, the outer peripheral surface (end portion) of the first bonding layer 152 is disposed on the inner side of the side surfaces 110a, 110b, 110c, and 110d of the multilayer body 110 over one circumference of the outer periphery. 174. As a result, leakage current generated through the first bonding layer 152, that is, leakage current flowing through the side electrodes 171, 173, and 174 through the first bonding layer 152 can be suppressed, and detection accuracy can be improved. Can do.

  Further, when viewed from the stacking direction LD, the end portion of the first bonding layer 153 has a portion that does not overlap the end portion of the fourth piezoelectric layer 133 and the end portion of the fifth piezoelectric layer 141. In the present embodiment, when viewed from the stacking direction LD, the end portion of the first bonding layer 153 does not overlap either the end portion of the fourth piezoelectric layer 133 or the end portion of the fifth piezoelectric layer 141. . That is, the outer peripheral surface (end portion) of the first bonding layer 153 is disposed on the inner side of the side surfaces 110a, 110b, 110c, and 110d of the multilayer body 110 over the entire circumference of the outer periphery. 174. Thereby, the leakage current generated through the first bonding layer 153, that is, the leakage current flowing through the side electrodes 171, 173 and 174 through the first bonding layer 153 can be suppressed, and detection accuracy is improved. Can do.

  Further, when viewed from the stacking direction LD, the end portion of the first bonding layer 154 has a portion that does not overlap the end portion of the sixth piezoelectric layer 143 and the end portion of the second cover base material 162. In the present embodiment, when viewed from the stacking direction LD, the end portion of the first bonding layer 154 does not overlap either the end portion of the sixth piezoelectric layer 143 or the end portion of the second cover base material 162. . That is, the outer peripheral surface (end portion) of the first bonding layer 154 is disposed on the inner side of the side surfaces 110a, 110b, 110c, and 110d of the multilayer body 110 over the entire circumference of the outer periphery. 174. Thereby, the leakage current generated through the first bonding layer 154, that is, the leakage current flowing through the side electrodes 171 173, and 174 through the first bonding layer 154 can be suppressed, and detection accuracy is improved. Can do.

  Thus, the leakage current generated through the first bonding layers 126, 136, 146, 151, 152, 153, and 154 can be suppressed, and the detection accuracy can be improved.

  The distance L1 between the outer peripheral surface of the first bonding layer 126 and the outer peripheral surfaces of the first piezoelectric layer 121 and the second piezoelectric layer 123 (the side surfaces 110a, 110b, 110c, and 110d of the multilayer body 110). Is not particularly limited and is appropriately set according to various conditions, but is preferably 0.05 mm or more and 2 mm or less, and more preferably 0.1 mm or more and 0.6 mm or less.

  If the distance L1 is smaller than the lower limit value, the leakage current generated through the first bonding layer 126 may increase. Further, when the distance L1 is larger than the upper limit value, the bonding strength between the first piezoelectric layer 121 and the second piezoelectric layer 123 may be reduced.

  The same applies to the distance L1 for the other first bonding layers 136, 146, and 151 to 154.

  Further, when viewed from the stacking direction LD, the first bonding layer 126 is included in the first output electrode layer 124 and the second output electrode layer 125. In other words, the first bonding layer 126 overlaps the first output electrode layer 124 and the second output electrode layer 125. Specifically, as viewed from the stacking direction LD, the first bonding layer 126 has an end on the side electrode 171 side, and an end on the side electrode 171 side of the first output electrode layer 124 and the second output electrode layer 125. The first output electrode layer 124 and the second output electrode layer 125 have the same shape except that they are located on the inner side.

  Similarly, the other first bonding layers 136, 146, and 151 to 154 are respectively arranged as output electrode layers and ground electrodes disposed above and below (next to) the first bonding layer as viewed from the stacking direction LD. Is included in the layer. That is, the first bonding layers 136, 146, and 151 to 154 also overlap the output electrode layer and the ground electrode layer that are disposed above and below the first bonding layer, respectively, when viewed from the stacking direction LD. .

  As described above, the first base 2 and the second base 3 are fixed by the pressurizing bolt 71.

  The fixing with the pressurizing bolt 71 is carried out in such a manner that the pressurizing bolt 71 is protruded from the side wall 33 side of the second base portion 3 with the sensor devices 6 disposed between the top surface 231 and the inner wall surface 331. The male screw (not shown) of the pressurizing bolt 71 is screwed into a female screw 241 formed on the first base 2. In this way, the charge output element 10 is applied with a predetermined pressure, that is, a pressurized pressure, by the first base 2 and the second base 3 together with the package 60 that houses the charge output element 10.

  The first base portion 2 and the second base portion 3 can be displaced (moved) by a predetermined amount with respect to one sensor device 6 by two pressurizing bolts 71, that is, a total of eight pressurizing bolts 71. To be fixed. By fixing the first base 2 and the second base 3 so that a predetermined amount can be displaced from each other, an external force (shearing force) is applied to the force detection device 1 so that a shearing force is applied to the charge output element 10. When acting, the frictional force between the layers constituting the charge output element 10 is surely generated, so that the charge can be reliably detected. Further, the pressurizing direction by each pressurizing bolt 71 is a direction parallel to the stacking direction LD.

  In addition, the force FA of the whole force detection apparatus 1, the force FB in the β axis direction, the force FC in the γ axis direction, the force FC in the γ axis direction, the rotational force MA around the α axis, the rotational force MB around the β axis, and the rotation around the γ axis. The force MC is calculated based on a signal proportional to the amount of charge accumulated from each charge output element 10. In this embodiment, four charge output elements 10 are provided. However, if at least three charge output elements 10 are provided, the rotational forces MA, MB, and MC can be calculated.

  As described above, according to the force detection device 1, it is possible to suppress the leakage current generated through the first bonding layers 126, 136, 146, and 151 to 154 and improve the detection accuracy. .

<Second Embodiment of Force Detection Device>
6 and 7 are cross-sectional views schematically showing the charge output element in the second embodiment of the force detection device of the present invention. 6 corresponds to FIG. 4 of the first embodiment, and FIG. 7 corresponds to FIG. 5 of the first embodiment.

  Hereinafter, although the second embodiment will be described, the description will focus on the differences from the first embodiment described above, and the description of the same matters will be omitted.

  As shown in FIGS. 6 and 7, in the force detection device 1 of the second embodiment, the charge output element 10 includes second bonding layers 181, 182, 183, 184, 185, 186 and 187.

  The second bonding layer 181 is provided between the first cover base material 161 and the first piezoelectric layer 121, and the end portion (outer peripheral portion) of the first cover base material 161 and the first piezoelectric layer. The end part (outer peripheral part) of 121 is joined. The second bonding layer 181 is in contact with the side electrodes 171, 173, and 174, but is separated from the first bonding layer 151 and the ground electrode layer 111.

  Accordingly, it is possible to improve the bonding strength between the first cover base material 161 and the first piezoelectric layer 121 while suppressing a leakage current generated through the first bonding layer 151.

  The same applies to the other second bonding layers 182, 183, 184, 185, 186 and 187.

  That is, the second bonding layer 182 is provided between the first piezoelectric layer 121 and the second piezoelectric layer 123, and the end portion (outer peripheral portion) of the first piezoelectric layer 121 and the second piezoelectric layer. The end part (outer peripheral part) of the body layer 123 is joined. The second bonding layer 182 is in contact with the side electrodes 172, 173, and 174, but is separated from the first bonding layer 126, the first output electrode layer 124, and the second output electrode layer 125. .

  As a result, it is possible to improve the bonding strength between the first piezoelectric layer 121 and the second piezoelectric layer 123 while suppressing the leakage current generated through the first bonding layer 126.

  The second bonding layer 183 is provided between the second piezoelectric layer 123 and the third piezoelectric layer 131, and the end (outer peripheral portion) of the second piezoelectric layer 123 and the third piezoelectric layer. The end portion (outer peripheral portion) of 131 is joined. The second bonding layer 183 is in contact with the side electrodes 171, 173, and 174, but is separated from the first bonding layer 152 and the ground electrode layers 112 and 113.

  Thereby, it is possible to improve the bonding strength between the second piezoelectric layer 123 and the third piezoelectric layer 131 while suppressing the leak current generated through the first bonding layer 152.

  The second bonding layer 184 is provided between the third piezoelectric layer 131 and the fourth piezoelectric layer 133, and the end portion (outer peripheral portion) of the third piezoelectric layer 131 and the fourth piezoelectric layer. The end part (outer peripheral part) of the body layer 133 is joined. The second bonding layer 184 is in contact with the side electrodes 171, 172 and 173, but is separated from the first bonding layer 136, the third output electrode layer 134 and the fourth output electrode layer 135. .

  Thereby, the bonding strength between the third piezoelectric layer 131 and the fourth piezoelectric layer 133 can be improved while suppressing the leakage current generated through the first bonding layer 136.

  The second bonding layer 185 is provided between the fourth piezoelectric layer 133 and the fifth piezoelectric layer 141, and the end (outer peripheral portion) of the fourth piezoelectric layer 133 and the fifth piezoelectric layer. The end part (outer peripheral part) of the body layer 141 is joined. The second bonding layer 185 is in contact with the side electrodes 171, 173 and 174, but is separated from the first bonding layer 153 and the ground electrode layers 114 and 115.

  Thereby, the bonding strength between the fourth piezoelectric layer 133 and the fifth piezoelectric layer 141 can be improved while suppressing the leakage current generated through the first bonding layer 153.

  The second bonding layer 186 is provided between the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143, and the end portion (outer peripheral portion) of the fifth piezoelectric layer 141 and the sixth piezoelectric layer 141 are provided. The end part (outer peripheral part) of the body layer 143 is joined. The second bonding layer 186 is in contact with the side electrodes 171, 172, and 174, but is separated from the first bonding layer 146, the fifth output electrode layer 144, and the sixth output electrode layer 145. .

  As a result, it is possible to improve the bonding strength between the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143 while suppressing leakage current generated through the first bonding layer 146.

  The second bonding layer 187 is provided between the second cover base material 162 and the sixth piezoelectric layer 143, and the end portion (outer peripheral portion) of the second cover base material 162 and the sixth piezoelectric layer 143. The end part (outer peripheral part) of the body layer 143 is joined. The second bonding layer 187 is in contact with the side electrodes 171, 173 and 174, but is separated from the first bonding layer 154 and the ground electrode layer 116.

  Thereby, the bonding strength between the second cover base material 162 and the sixth piezoelectric layer 143 can be improved while suppressing the leakage current generated through the first bonding layer 154.

  Further, the distance L2 between the inner peripheral surface of the second bonding layer 182 and the outer peripheral surfaces of the first bonding layer 126, the first output electrode layer 124, and the second output electrode layer 125 is not particularly limited, Although it is suitably set according to various conditions, it is preferably 0.05 mm or more and 2 mm or less, and more preferably 0.1 mm or more and 0.6 mm or less.

If the distance L2 is smaller than the lower limit value, the leakage current generated through the first bonding layer 126 may increase. Further, if the distance L2 is larger than the upper limit value, the bonding strength between the first piezoelectric layer 121 and the second piezoelectric layer 123 may be reduced.
The same applies to the distance L2 for the other second bonding layers 181, 183 to 187.

  According to the second embodiment as described above, the same effect as that of the first embodiment described above can be exhibited.

  Further, between the first cover substrate 161 and the first piezoelectric layer 121 of the charge output element 10, between the first piezoelectric layer 121 and the second piezoelectric layer 123, and the second piezoelectric body. Between the layer 123 and the third piezoelectric layer 131, between the third piezoelectric layer 131 and the fourth piezoelectric layer 133, and between the fourth piezoelectric layer 133 and the fifth piezoelectric layer 141. In the meantime, the bonding strength between the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143 and between the sixth piezoelectric layer 141 and the second cover base material 162 can be improved. It is possible to realize the charge output element 10 and the force detection device 1 having high characteristics.

<Embodiment of single arm robot>
Next, based on FIG. 8, a single-arm robot which is an embodiment of the robot of the present invention will be described. Hereinafter, the present embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  FIG. 8 is a view showing an example of a single-arm robot using the force detection device of the present invention. The single-arm robot 500 of FIG. 8 includes a base 510, an arm 520, an end effector 530 provided on the distal end side of the arm 520, and a force detection device 1 provided between the arm 520 and the end effector 530. Have In addition, as the force detection apparatus 1, the thing similar to each embodiment mentioned above is used.

  The base 510 has a function of accommodating an actuator (not shown) that generates power for rotating the arm 520, a control unit (not shown) that controls the actuator, and the like. The base 510 is fixed on, for example, a floor, a wall, a ceiling, or a movable carriage.

  The arm 520 includes a first arm element 521, a second arm element 522, a third arm element 523, a fourth arm element 524, and a fifth arm element 525, and rotates adjacent arms. It is configured by linking freely. The arm 520 is driven by being rotated or bent in a compound manner around the connecting portion of each arm element under the control of the control unit.

  The end effector 530 has a function of gripping an object. The end effector 530 has a first finger 531 and a second finger 532. After the end effector 530 reaches a predetermined operating position by driving the arm 520, the object can be gripped by adjusting the distance between the first finger 531 and the second finger 532.

  The end effector 530 is a hand here, but the present invention is not limited to this. Other examples of the end effector include, for example, a component inspection device, a component transport device, a component processing device, a component assembly device, and a measuring instrument. The same applies to the end effectors in other embodiments.

  The force detection device 1 has a function of detecting an external force applied to the end effector 530. By feeding back the force detected by the force detection device 1 to the control unit of the base 510, the single-arm robot 500 can perform more precise work. Further, the single arm robot 500 can detect contact of the end effector 530 with an obstacle or the like by the force detected by the force detection device 1. Therefore, an obstacle avoidance operation, an object damage avoidance operation, and the like, which are difficult with conventional position control, can be easily performed, and the single-arm robot 500 can perform work more safely.

  In the illustrated configuration, the arm 520 includes a total of five arm elements, but the present invention is not limited to this. When the arm 520 is constituted by one arm element, when constituted by 2 to 4 arm elements, and when constituted by 6 or more arm elements, it is within the scope of the present invention. .

<Embodiment of double-arm robot>
Next, a multi-arm robot which is an embodiment of the robot of the present invention will be described with reference to FIG. Hereinafter, the present embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  FIG. 9 is a diagram showing an example of a multi-arm robot using the force detection device of the present invention. 9 includes a base 610, a first arm 620, a second arm 630, a first end effector 640a provided on the distal end side of the first arm 620, a second arm 620, and a second end effector 640a. A second end effector 640b provided on the distal end side of the arm 630, and between the first arm 620 and the first end effector 640a and between the second arm 630 and the second end effector 640b. A force detection device 1 is provided. In addition, as the force detection apparatus 1, the thing similar to each embodiment mentioned above is used.

  The base 610 has a function of accommodating an actuator (not shown) that generates power for rotating the first arm 620 and the second arm 630, a control unit (not shown) that controls the actuator, and the like. Have. The base 610 is fixed on, for example, a floor, a wall, a ceiling, or a movable carriage.

  The 1st arm 620 is comprised by connecting the 1st arm element 621 and the 2nd arm element 622 so that rotation is possible. The second arm 630 is configured by rotatably connecting the first arm element 631 and the second arm element 632. The first arm 620 and the second arm 630 are driven by being complexly rotated or bent around the connecting portion of each arm element under the control of the control unit.

  The first and second end effectors 640a and 640b have a function of gripping an object. The first end effector 640a has a first finger 641a and a second finger 642a. The second end effector 640b has a first finger 641b and a second finger 642b. After the first end effector 640a reaches a predetermined operating position by driving the first arm 620, the object is grasped by adjusting the distance between the first finger 641a and the second finger 642a. Can do. Similarly, after the second end effector 640b reaches a predetermined operating position by driving the second arm 630, the distance between the first finger 641b and the second finger 642b is adjusted to thereby adjust the object. It can be gripped.

  The force detection device 1 has a function of detecting an external force applied to the first and second end effectors 640a and 640b. By feeding back the force detected by the force detection device 1 to the control unit of the base 610, the multi-arm robot 600 can perform the operation more precisely. The multi-arm robot 600 can detect contact of the first and second end effectors 640a and 640b with an obstacle by the force detected by the force detection device 1. Therefore, an obstacle avoidance operation, an object damage avoidance operation, and the like that have been difficult with conventional position control can be easily performed, and the multi-arm robot 600 can perform the operation more safely.

  In the illustrated configuration, there are a total of two arms, but the present invention is not limited to this. The case where the multi-arm robot 600 has three or more arms is also within the scope of the present invention.

  As described above, the sensor element, the force detection device, and the robot of the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each unit may be any arbitrary function having the same function. It can be replaced with that of the configuration. In addition, any other component may be added to the present invention.

  In addition, the present invention may be a combination of any two or more configurations (features) of the embodiment.

  Further, in the present invention, instead of the pressurizing bolt, for example, an element that does not have a function of applying a pressurization to the charge output element (sensor element) may be used, and a fixing method other than the bolt is adopted. May be.

  In the present embodiment, the number of charge output elements is four. However, in the present invention, the number of charge output elements may be one, two, three, or five or more.

  In the present embodiment, the charge output element includes the first sensor, the second sensor, and the third sensor. However, in the present invention, the charge output element includes one sensor. Two or four or more may be used.

  In addition, the robot of the present invention is not limited to an arm type robot (robot arm) as long as it has an arm, but is another type of robot such as a scalar robot, a legged walking (running) robot, or the like. Also good.

  The force detection device of the present invention is not limited to a robot, but other devices, for example, a transport device such as an electronic component transport device, an inspection device such as an electronic component inspection device, a vibration meter, an accelerometer, a gravimeter, a dynamometer It can also be applied to measuring devices such as seismometers and inclinometers, input devices, parts processing devices, moving bodies, and the like.

DESCRIPTION OF SYMBOLS 1 ... Force detection apparatus 2 ... 1st base 22 ... Bottom plate 23 ... Convex part 221 ... Lower surface (1st surface)
231 ... Top surface 24 ... Wall part 241 ... Female screw 271 ... Center axis 272 ... Center 3 ... Second base 32 ... Top plate 33 ... Side wall 321 ... Upper surface (second surface)
331 ... Inner wall surface 4 ... Analog circuit board 41 ... Hole 43 ... Pipe 5 ... Digital circuit board 6, 6A, 6B, 6C, 6D ... Sensor device (pressure detector)
60 ... Package (container)
DESCRIPTION OF SYMBOLS 71 ... Pressurizing volt | bolt 10 ... Charge output element 110 ... Laminated body 110a, 110b, 110c, 110d ... Side surface 111-116 ... Ground electrode layer 12 ... 1st sensor 121 ... 1st piezoelectric material layer 123 ... 2nd piezoelectric material Body layer 124 ... first output electrode layer 125 ... second output electrode layer 126 ... first bonding layer 13 ... second sensor 131 ... third piezoelectric layer 133 ... fourth piezoelectric layer 134 ... third Output electrode layer 135 ... Fourth output electrode layer 136 ... First bonding layer 14 ... Third sensor 141 ... Fifth piezoelectric layer 143 ... Sixth piezoelectric layer 144 ... Fifth output electrode layer 145 ... Sixth output electrode layer 146 ... first bonding layer 151-154 ... first bonding layer 161 ... first cover substrate 162 ... second cover substrate 171 ... first side electrode 172 ... second side electrode 173 ... Third side Electrodes 174 ... fourth side electrodes 181 to 187 ... second bonding layer 500 ... single-arm robot 510 ... base 520 ... arm 521 ... first arm element 522 ... second arm element 523 ... third arm element 524 ... Fourth arm element 525 ... Fifth arm element 530 ... End effector 531 ... First finger 532 ... Second finger 600 ... Multi-arm robot 610 ... Base 620 ... First arm 621 ... First arm Element 622 ... second arm element 630 ... second arm 631 ... first arm element 632 ... second arm element 640a ... first end effector 641a ... first finger 642a ... second finger 640b ... second Second end effector 641b ... first finger 642b ... second finger NL1, NL2 ... normal Qx, Qy, Qz ... charge

Claims (18)

A first piezoelectric plate;
A second piezoelectric plate laminated with the first piezoelectric plate in the thickness direction of the first piezoelectric plate;
A first bonding layer that laminates the first piezoelectric plate and the second piezoelectric plate;
When viewed from the thickness direction, the end portion of the first bonding layer has a portion that does not overlap the end portion of the first piezoelectric plate and the end portion of the second piezoelectric plate.   2. The sensor element according to claim 1, wherein when viewed from the thickness direction, the end portion of the first bonding layer does not overlap either the end portion of the first piezoelectric plate or the end portion of the second piezoelectric plate. Having side electrodes provided on side surfaces parallel to the thickness direction;
The sensor element according to claim 1, wherein an end portion of the first bonding layer and the side electrode are separated from each other. An internal electrode provided on one of a main surface intersecting the thickness direction of the first piezoelectric plate and a main surface intersecting the thickness direction of the second piezoelectric plate;
4. The sensor element according to claim 1, wherein the first bonding layer overlaps the internal electrode when viewed from the thickness direction. 5.   5. The sensor element according to claim 1, further comprising: a second bonding layer provided at an end of the first piezoelectric plate and the second piezoelectric plate and spaced apart from the first bonding layer. 6. An internal electrode provided on one of a main surface intersecting the thickness direction of the first piezoelectric plate and a main surface intersecting the thickness direction of the second piezoelectric plate;
The sensor element according to claim 5, wherein the second bonding layer and the internal electrode are separated from each other. A force detection device including a force sensor element,
The force sensor element includes a first piezoelectric plate,
A second piezoelectric plate laminated with the first piezoelectric plate in the thickness direction of the first piezoelectric plate;
A first bonding layer that laminates the first piezoelectric plate and the second piezoelectric plate;
When viewed from the thickness direction, the end portion of the first bonding layer has a portion that does not overlap the end portion of the first piezoelectric plate and the end portion of the second piezoelectric plate.   The force detection device according to claim 7, wherein when viewed from the thickness direction, the end portion of the first bonding layer does not overlap either the end portion of the first piezoelectric plate or the end portion of the second piezoelectric plate. Having side electrodes provided on side surfaces parallel to the thickness direction;
The force detection device according to claim 7 or 8, wherein an end portion of the first bonding layer and the side surface electrode are separated from each other. An internal electrode provided on one of a main surface intersecting the thickness direction of the first piezoelectric plate and a main surface intersecting the thickness direction of the second piezoelectric plate;
10. The force detection device according to claim 7, wherein the first bonding layer overlaps the internal electrode when viewed from the thickness.   11. The force detection device according to claim 7, further comprising a second bonding layer provided at an end of the first piezoelectric plate and the second piezoelectric plate and spaced apart from the first bonding layer. An internal electrode provided on one of a main surface intersecting the thickness direction of the first piezoelectric plate and a main surface intersecting the thickness direction of the second piezoelectric plate;
The force detection device according to claim 11, wherein the second bonding layer and the internal electrode are separated from each other. Arm,
An end effector provided on the arm;
A force detection device that is provided between the arm and the end effector and detects an external force applied to the end effector,
The force detection device includes a force sensor element,
The force sensor element includes a first piezoelectric plate,
A second piezoelectric plate laminated with the first piezoelectric plate in the thickness direction of the first piezoelectric plate;
A first bonding layer that laminates the first piezoelectric plate and the second piezoelectric plate;
When viewed from the thickness direction, the end of the first bonding layer has a portion that does not overlap the end of the first piezoelectric plate and the end of the second piezoelectric plate.   14. The robot according to claim 13, wherein when viewed from the thickness direction, the end portion of the first bonding layer does not overlap either the end portion of the first piezoelectric plate or the end portion of the second piezoelectric plate. Having side electrodes provided on side surfaces parallel to the thickness direction;
The robot according to claim 13 or 14, wherein an end of the first bonding layer and the side electrode are separated from each other. An internal electrode provided on one of a main surface intersecting the thickness direction of the first piezoelectric plate and a main surface intersecting the thickness direction of the second piezoelectric plate;
The robot according to claim 13, wherein the first bonding layer overlaps with the internal electrode when viewed from the thickness.   17. The robot according to claim 13, further comprising: a second bonding layer that is provided at an end of the first piezoelectric plate and the second piezoelectric plate and is spaced apart from the first bonding layer. An internal electrode provided on one of a main surface intersecting the thickness direction of the first piezoelectric plate and a main surface intersecting the thickness direction of the second piezoelectric plate;
The robot according to claim 17, wherein the second bonding layer and the internal electrode are separated from each other.

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