JPH11281554A - Material testing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material testing machine by which a load to be applied to a specimen can be controlled smoothly, whose measuring accuracy can be increased sufficiently and whose practicality is high. SOLUTION: A moving member which is installed so as to be freely advanced, retreated and moved in the direction of a load applied to a specimen placed on a testing machine body is provided, and a shaft body 24 which supports the moving body so as to be movable to its axial direction is provided. Then, the moving member is shaft-supported in a noncontact manner with reference to the shaft body 24 especially by an air bearing 27 which is built in the bearing part of the moving member. By using a linear motor mechanism 30 which is composed of a first magnetic mechanism 31 installed along the shaft body 24 and a second magnetic mechanism 32 which is built in the moving member and which is magnetically coupled to the first magnetic mechanism 31, the moving member is driven in a noncontact manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material testing machine for testing material properties of a test specimen from a relationship between a load and a displacement of the specimen to which a load is applied, and more particularly to a method for smoothly controlling a load applied to the test specimen. And a material testing machine capable of increasing the measurement accuracy by controlling the measurement accuracy.

[0002]

[Related Background Art] A material testing machine for testing the material properties of a specimen such as a material specimen is a means for applying a load such as a compressive load or a tensile load to the specimen, and a means for applying a load to the specimen by the load. Load detecting means such as a load cell for detecting the applied load, and displacement detecting means such as a position detector for detecting displacement such as elongation, contraction, or bending generated in the specimen by the load. You. The material properties such as strength and proof stress of the specimen are determined from the relationship between the detected load and displacement.

[0003]

As means for applying a load to the specimen, a hydraulic cylinder is generally used, but a high-pressure hydraulic source, a hydraulic servo mechanism, and the like are required, and the configuration is large. It cannot be denied.
Therefore, recently, it has been considered to use a ball feed screw mechanism as a load means in a small material testing machine for evaluating the strength and reliability of a dissimilar material micro-joined structure in an electronic device or the like.

However, this type of ball feed screw mechanism has problems of pitch accuracy and fluctuation in the ball feed screw, and is provided between the ball feed screw and its driving motor to reduce the driving force. Since there is a problem of backlash in the mechanism, there is a problem that the load applied to the specimen cannot be controlled smoothly. In particular, there is a problem that it is difficult to apply a load smoothly while giving a small displacement of about several tens of μm.

Further, when a small displacement is applied as a load to be applied to the specimen, a bearing for supporting the ball feed screw, for example, a bearing composed of a ball bearing, or a ball feed screw mechanism, which is moved and driven to apply to the specimen. Friction at a thrust bearing that supports a moving member to which a load is applied so as to be movable in the moving axis direction also poses a problem. Therefore, it has been difficult to increase the measurement accuracy.

The present invention has been made in view of such circumstances, and an object of the present invention is to allow a load applied to a test specimen to be smoothly controlled, and to allow a load and a displacement in the loaded test specimen to be controlled. In view of the above, it is an object of the present invention to provide a highly practical material testing machine capable of sufficiently increasing the measurement accuracy in testing the material characteristics.

[0007]

In order to achieve the above-mentioned object, a material testing machine according to the present invention comprises: a moving member movably provided in a direction of a load applied to a specimen mounted on a testing machine main body; A shaft body that supports the moving member so as to be movable in the axial direction, and particularly forms a bearing portion for the moving body with respect to the shaft body, and introduces compressed air between the moving member and the moving body to form the moving member. A first magnetic mechanism provided with an air bearing that holds the shaft in a non-contact manner with respect to the shaft, and provided along the shaft, for example, including a plurality of permanent magnets,
A linear motor mechanism including a second magnetic mechanism including, for example, an electromagnetic coil, which is incorporated in the moving member and is disposed opposite to the first magnetic mechanism and magnetically coupled, is provided as a drive source thereof. It is characterized by.

That is, in the material testing machine according to the present invention, a moving member movably supported by a shaft is provided as a load means for applying a load to the specimen, and an air bearing incorporated in a bearing portion of the moving member is provided. Thereby, the moving member is supported in a non-contact manner with respect to the shaft body, while a first magnetic mechanism provided along the shaft body and the first magnetic mechanism incorporated in the moving member are provided. The moving member is driven in a non-contact manner by using a linear motor mechanism including a second magnetic mechanism magnetically coupled to the magnetic mechanism, and the load is applied by a thrust of the linear motor mechanism. And

In a preferred aspect of the present invention, the bearing of the moving member is provided so as to surround the shaft body. Further, as set forth in claim 3, both ends of the shaft body are fixed to a base of a tester main body, and the movable member is provided so as to axially movably support the moving member, and forms the linear motor mechanism. By disposing a plurality of thrust magnets as the first magnetic mechanism on the base along the shaft, and incorporating an electromagnetic coil forming the second magnetic mechanism into the moving member, A magnetic gap is formed between the first and second magnetic mechanisms in the width direction.

According to a preferred aspect of the present invention, in the air bearing, in the air bearing, a lateral direction extends from an inner surface of a bearing portion of the moving member surrounding the shaft to a side surface of the shaft. And the compressed air is blown from the lower surface side of the moving member to the pedestal provided along the shaft body so as to face the lower surface of the moving member, so that the moving member is lifted. Thus, the bearing portion and the shaft body are kept in a non-contact state.

It is preferable that the linear motor mechanism is servo-controlled while detecting position information of the moving member with respect to the shaft body, as described in claim 5.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a small-sized material testing machine according to an embodiment of the present invention will be described with reference to the drawings. The material testing machine according to this embodiment is suitable for use in, for example, evaluating the strength and mechanical properties of a specimen having a micro-joined structure of a dissimilar material, such as a component used in an electronic device or an electronic device. And is realized as a desktop type device that operates using electricity as a power source.

FIG. 1 is a perspective view showing a schematic configuration of a main body of a material testing machine, and 1 is a base made of a surface plate having an anti-vibration structure. On the base 1, a first unit 10 and a second unit 20 for applying a load consisting of a load or displacement such as compression, tension, or bending to a specimen S to be subjected to a test.
Are mounted separately from each other in the direction in which the load is applied (X-axis direction).

The first unit 10 has two axes (Y-axis) provided perpendicular to the load direction (X-axis direction).
An axis and a Z-axis) table is mainly used, and for example, a chuck 11 for holding one end of the specimen S is attached to the biaxial table. And with a two-axis table,
The chuck 11 is provided such that its position can be adjusted in the depth direction (Y-axis direction) and the vertical direction (Z-axis direction) of the base 1. Also, the second unit 20
Is mainly composed of a moving table provided so as to be movable in the load direction (X-axis direction). The moving table is provided with a chuck 21 paired with the chuck 11 attached to the moving table. The chuck 21 serves, for example, to hold the other end of the specimen S and apply a load to the specimen S as the movable table moves in the X-axis direction.

Here, both ends of the specimen S are held by a pair of chucks 11 and 21, and the position of the chuck 21 in the X-axis direction is displaced by driving a moving table, whereby the specimen S is compressed. Although a description will be given assuming that a load consisting of a load or a tensile load is applied, it is of course possible to apply a compressive displacement or a tensile displacement as a load. The specimen S is placed on one of the chucks 11 and 21 by X
Attached in the direction (YZ plane) perpendicular to the axis,
By mounting a jig that bends the specimen S on the other side of the specimens 1 and 21, a bending load or bending displacement is applied to the specimen S in a direction perpendicular to the specimen S by driving the moving table. Is also possible.

The first unit 10 is mounted on the base 1
An X table 12 mounted thereon so as to be adjustable in the X-axis direction and serving as a base of the above-described two-axis table, and a screen-shaped Y table 13 mounted on the X table 12 so as to be adjustable in the Y-axis direction. , And this Y table 13
A Z table 14 which is mounted on the vertical wall surface of the Z
And an axis table. And the chuck 11
Is fixedly supported on the Z table 14 via a rod-shaped load cell 15 and a rod-shaped holding member 16 for holding the load cell 15 as described later.

Incidentally, the X table 12 is attached to the base 1 by bolts after the mounting position on the base 1 is adjusted according to the length of the specimen S mounted between the chucks 11 and 21. Is firmly fixed. Further, the Y table 13 constituting the biaxial table is provided so that its position can be adjusted in the Y axis direction while its base is guided by a rail provided on the upper surface of the X table 12. The Y table 13 includes a pair of left and right feed screw mechanisms 13 provided at both ends of the X table 12 as shown in FIG.
After the position is adjusted with high precision by a and 13a, it is firmly fixed to the X table 12 by bolting. Further, the Z table 14 is held by a guide body 13b provided on an upright surface (front surface) of the Y table 13, and
It is provided so that the position can be adjusted in the axial direction. Then, after the position is adjusted with high precision by a pair of upper and lower feed screw mechanisms 14a, 14a provided at the upper and lower ends of the guide body 13b, it is firmly fixed to the Y table 13 by bolting.

The position adjustment of the Y table 13 and the Z table 14 is performed so that the axis between the pair of chucks 11 and 12 is adjusted with high accuracy. The feed screw mechanisms 13a, 13a, 14a, and 14a advance and retreat their shafts by rotation of a thimble having a built-in ratchet stop mechanism as seen in a micrometer, and the shafts cause the respective tables 13, 14 to move. The position is displaced by pressing the side surface.

On the other hand, the chuck 1 is mounted on the front surface of the Z stage 14 via the load cell 15 and the holding member 16.
1 is mounted as follows. For example, the rod-shaped load cell 15 is provided perpendicular to the load direction (X-axis direction), physically constitutes a parallel link, receives a load at one end thereof, and displaces the two ends in parallel. The load applied to the one end is electrically detected in accordance with the deflection of the main body caused by the parallel displacement. In particular, the load is detected with high resolution and high accuracy by increasing the length of the load cell 15 in the Y-axis direction. It is needless to say that a conventional general magnetostrictive type can be used instead of the rod-shaped load cell 15.

The holding member 16 fixedly holds the other end (fixed end) of the load cell 15 at a position distant from the axis of the load cell 15.
The one end side (displacement end) to which the load is applied is made to coincide with the axis of the Z table 14, and is a rod-shaped body arranged substantially parallel to the load cell 15. The load cell 15 is supported by using such a holding member 16,
By attaching the chuck 11 to the displacement end of the load cell 15, the chuck 11 is arranged on the axis of the Z table 14 so that the load applied to the chuck 11 can be reliably received by the Z table 14. I have.

In contrast to the first unit 10 configured as described above, the second unit 20 having the characteristic function of the present invention is configured as follows. That is, as described above, the second unit 20 mainly includes a movable table provided on the base 1 so as to be movable in the load direction (X-axis direction), and the chuck 21 is attached to the movable table. Is done. This moving table is fixed on the base 1 as shown in FIG. 3, and has legs 23, 23 between both ends in the X-axis direction of a pedestal 22 forming a storage space for a linear motor mechanism to be described later. The movable table 25 is provided so as to be able to move forward and backward in the load direction (X-axis direction). The chuck 21 is provided with a substantially triangular block 2 on such a moving table 25.
6 and is fixed to the vertical surface at the front end and opposed to the chuck 11 of the first unit 10.

The moving table 25 has an upper structure 25a to which the block body 26 is fixed, and a pair of side structures 25b, 2 on the lower surface side of the upper structure 25a.
5b comprising a lower structure 25c fixed via
As shown in FIG. 4, the cross-sectional structure has a structure in which a bearing portion surrounding the shaft body 24 having the rectangular cross section described above is formed. In particular, the side structures 25b, 25b and the lower structure 25
An air introduction passage 27 is formed in c for introducing compressed air through the inside thereof. The opening of the air introduction passage 27 is formed in the bearing structure, in particular, in the side structure 2.
5b, 25b, so that the compressed air introduced through the air introduction passage 27 is blown between the side structure bodies 25b, 25b and the side surface of the shaft body 24. It has become. The opening of the air introduction passage 27 is also formed on the lower surface of the lower structure 25c, and the compressed air is also blown between the opening and the upper surface of the pedestal 22 via the opening. I have.

The moving table 25 is lifted from the upper surface of the pedestal 22 by a small gap ΔV by the above-mentioned blowing of the compressed air introduced through the air introducing passage 27, and is floated from the shaft body 24. Shaft 24
, Small gaps ΔL, ΔR are formed on both sides, respectively.
An air bearing for keeping the moving table 25 and the shaft body 24 and the pedestal 22 in a non-contact state is realized. By the action of the air bearing, the moving table 25 can smoothly move between the moving table 25 and the shaft body 24 without being affected by frictional resistance.

On the other hand, a plurality of rod-shaped permanent magnets 31 are arranged along the shaft 24 at predetermined pitches in the space opened laterally at the center of the pedestal 22 while alternately changing the polarity thereof. They are arranged at equal intervals. These permanent magnets 31 have, for example, both poles positioned at both ends in the width direction (Y-axis direction) of the pedestal 22, respectively, and constitute a first magnetic mechanism of the linear motor mechanism 30. Also, an electromagnetic coil 32 forming a second magnetic mechanism of the linear motor mechanism 30
Are mounted on both sides of the moving table 25 by being incorporated in the coil holding member 33, and the magnetic poles thereof are arranged opposite to the ends (poles) of the permanent magnet 31 with a minute gap ΔY therebetween. Magnetically coupled. More specifically, a magnetic pole (not shown) of the electromagnetic coil 32 is disposed to face the permanent magnet 31.

The linear motor mechanism 3 configured as described above
0 controls the driving phase of the electromagnetic coil 32 to generate an attractive / repulsive force between the N pole and the S pole of the permanent magnet 31 fixedly disposed as described above. A moving thrust is generated in the direction in which the permanent magnets 31 are arranged, whereby the permanent magnets 31 move sequentially between the permanent magnets 31. With such a linear motor mechanism 30, the moving table 2
5 is controlled to move in the X-axis direction along the shaft body 24, and the thrust of the linear motor mechanism 30 is applied as the load described above.

The moving table 25 driven by the linear motor mechanism 30 incorporates, for example, an optical position sensor for detecting a moving displacement position with respect to the shaft 24. The linear motor mechanism 30 is servo-controlled in accordance with position information (displacement information) detected by such a position sensor, and its moving position is controlled with high precision. Incidentally, in the moving table according to this embodiment, the moving stroke L of the moving table 25 is set to a maximum of 100 mm, and 0.1 μm.
The position of the moving table 25 can be controlled with high precision at a resolution of m.

Further, as shown in FIG.
At the front and rear ends in the movement direction of No. 5, detection pieces 35 for limiting the movement range are provided. When the moving table 25 reaches the limit of its moving range, the detecting piece 35 enters the optical path of the photocouplers 36, 36 attached to the legs 23, 23 and blocks the optical path. The movement limit position (stop position) of the movement table 25 is detected.

Thus, as described above, the linear motor mechanism 3
0, and the shaft 2 is moved via an air bearing.
As described above, the moving table 25 which is supported by the chuck 4 and moves in the X-axis direction has the chuck 21 via the block body 26 as described above.
The chuck 21 is arranged to face the chuck 11 mounted on the first unit 10 as shown in FIG. A specimen S to be subjected to a material test is mounted between the chucks 11 and 21.

At this time, as described above, the first unit 10
The position between the chucks 11 and 21 is adjusted by the position adjustment in the Y-axis direction and the Z-axis direction by the two-axis table in the above.
It is mounted between 21. In this state, when the linear motor mechanism 30 of the second unit 20 is driven, the moving table, and eventually the chuck 21 advances and retreats in the X-axis direction, and a load is applied to the specimen S. Then, the load applied to the specimen S by this load is detected via the load cell 15.

On the other hand, arm bodies 41 and 42 extending in the lateral direction are respectively attached to the bases of the chucks 11 and 21. The arm bodies 41 are mounted on a magnet scale having a slide shaft in the X-axis direction. Is mounted. A jig 44 for displacing the slide shaft of the displacement meter 43 is provided on the arm body 42 on the chuck 21 side via a feed screw mechanism 45 so as to be adjustable in position. The feed screw mechanism 45 plays a role of zero-adjusting the slide axis of the displacement meter 43 displaced by the jig 44 when the specimen S is in a no-load state.

The displacement meter 43 attached between the chucks 11 and 21 thus directly (absolutely) measures the displacement consisting of the compression and expansion of the specimen S attached between the chucks 11 and 21. . That is, the displacement (movement position) of the chuck 21 moved by the linear motor mechanism 30 that is servo-controlled as described above is detected by the above-described position sensor. However, as shown in FIG.
This is the displacement of the distance L1 between the unit 10 and the moving table of the second unit 20, and the load cell 1
5 includes the deflection displacement. Therefore, instead of the displacement of the chuck 21 detected by the position sensor, the displacement of the distance L2 between the chucks 11 and 21 is measured by the displacement meter 4.
3, the detection accuracy is sufficiently improved.

The tester main body including the first unit 10 and the second unit 20 configured as described above is controlled by a control unit 51 mainly including a microprocessor as shown in FIG. 6, for example. Driven under Specifically, the air pump 52 is operated to make the air bearing function, and in this state, the linear motor driving unit 53 is operated to drive the linear motor mechanism 30. The linear motor driving section 53 forms a servo control circuit, and detects the load from the control section 51 while detecting the position of the moving table 25 (the position of the chuck 21) with respect to the shaft body 24 using the position sensor described above. The linear motor mechanism 30 is driven in accordance with the displacement command. By the operation of the linear motor mechanism 30 driven in this manner, a load consisting of a load or a displacement is applied to the specimen S held between the chucks 11 and 21.

Thus, the load and its displacement in the specimen S loaded as described above are determined by the load cell 1
5 and the output of the displacement meter (magnet scale) 43 are detected by the load detecting unit 54 and the displacement detecting unit 55, respectively, and are taken in the measuring unit 56 of the control unit 51 as digital data sampled at a predetermined cycle, for example. Then, in the measuring section 56, for example, a predetermined measurement calculation process is performed to evaluate the material characteristics and the mechanical strength characteristics of the specimen S.

According to the material testing machine constructed as described above, in order to apply a load to the specimen S held between the pair of chucks 11 and 21,
And a movable table 25 movably provided in the load direction (X-axis direction) while supporting the movable table 25 in a non-contact manner using an air bearing with respect to a shaft 24 that supports the movable table 25. The driving source that causes the load by moving the moving table 25 is the moving table 25 and the pedestal 2.
Since the linear motor mechanism 30 is provided in a non-contact manner with the specimen 2, the specimen S can be smoothly loaded without causing a problem such as friction between members. In addition, the load state can be controlled smoothly.

According to the above-described embodiment, the movable table 25 is supported by the shaft 24 having a rectangular cross section.
The upper surface of the pedestal 22 and the moving table 25 (the lower structure 25
Since the moving table 25 is supported using an air bearing in a wide area between the lower surface and the lower surface of c),
Even when the moving table 25 is heavy, it can be stably supported. Further, by blowing compressed air to the side surface of the shaft 24, the shaft 24 and the side structure 25 are formed.
Since the gaps ΔL and ΔR with b are kept constant, it is possible to prevent the displacement of the moving table 25 in the width direction (Y-axis direction). In addition, the gap between the first magnetic mechanism and the second magnetic mechanism in the linear motor mechanism 30 can be kept constant. Therefore, also in this respect, effects such as stable and accurate movement driving of the moving table 25 and position control thereof can be achieved.

The present invention is not limited to the above embodiment. For example, a plurality of parallelly arranged round bars or the like can be used as the shaft body 24 that supports the moving table 25. By incorporating the linear motor mechanism 30 on the lower surface side of the moving table 25, it is possible to reduce the size of the moving table 25. Further, it is of course possible to construct a linear motor mechanism 30 by incorporating a permanent magnet on the moving table 25 side and arranging a plurality of electromagnetic coils on the pedestal 22 side.

In particular, in the linear motor mechanism 30, it is advantageous to increase the area of the first magnetic mechanism and the second magnetic mechanism facing the magnetic poles in order to obtain a large thrust.
7A shows a cross-sectional configuration, and FIG. 7B shows the relationship between the planar arrangement of the thrust magnet 31 and the electromagnetic coil 32. As shown in FIG. You can make it happen. The electromagnetic coil 32 is U
A phase, a V-phase, and a W-phase that can be driven by three-phase AC may be used. In this case, the upper surface of the base 22 and the lower surface of the moving table 25 are opposed to each other so as to face each other.
4 may be provided to restrict the displacement of the moving table 25 in the width direction by using the attraction force of the attraction magnet 34. At this time, the blowing force of the compressed air in the air bearing is set so as to cancel the downward force consisting of the attraction force of the attraction magnet 34 and the weight of the moving table 22. In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0038]

As described above, according to the present invention, an air bearing is provided between a moving member provided so as to be capable of moving forward and backward in a direction in which a load is applied to a specimen, and a shaft supporting the moving member. By providing this, the moving member is supported in a non-contact manner, and the moving member is driven to move in a non-contact manner by using a linear motor mechanism, so that the moving member can be smoothly and accurately moved without causing a problem such as friction. Can be controlled and moved. As a result, a load can be smoothly applied to the specimen, and the load state can be controlled with high precision and smoothness. For example, even when a small displacement of several tens of μm is applied, it is possible to perform the measurement with high accuracy while applying a large load of about 100 N with an accuracy of about 0.3 μm. The effect is achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a material testing machine according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a two-axis table in a first unit of the material testing machine according to the embodiment.

FIG. 3 is a diagram showing a configuration of a moving table in a second unit of the material testing machine according to the embodiment.

FIG. 4 is a sectional view showing a configuration of an air bearing between a shaft body and a moving table and an arrangement relationship of a linear motor mechanism.

FIG. 5 is a diagram showing a mounting structure of a position detector.

FIG. 6 is a block diagram showing an overall control system of the material testing machine.

FIG. 7 is a diagram showing another embodiment of the linear motor mechanism.

[Explanation of symbols]

 Reference Signs List 1 base 10 first unit 11 chuck 12 X table 13 Y table 14 Z table 15 load cell 16 holding member 20 second unit 21 chuck 22 pedestal 23 leg 24 shaft 25 moving table 26 block 27 air introduction path (air bearing) ) 30 linear motor mechanism 31 permanent magnet (first magnetic mechanism) 32 electromagnetic coil (second magnetic mechanism) 33 holding member 43 displacement meter

Claims (5)

[Claims] 1. A material testing machine for testing a material property of a test piece from a relationship between a load and a displacement of the test piece when a load is applied to the test piece, wherein a direction of the load applied to the test piece is determined. A moving member provided to be movable forward and backward; a shaft body movably supporting the moving member; forming a bearing portion for the moving member with respect to the shaft body, and introducing compressed air between the shaft body and An air bearing that holds the moving member in non-contact with the shaft, a first magnetic mechanism provided along the shaft, and an air bearing that is incorporated into the moving member and faces the first magnetic mechanism; A material testing machine comprising: a second magnetic mechanism arranged in a horizontal direction; and a linear motor mechanism for moving and driving the moving member by magnetic coupling between the first and second magnetic mechanisms. 2. The material testing machine according to claim 1, wherein a bearing portion of the moving member is provided so as to surround the shaft. 3. The shaft body has both ends fixed to a base of a tester main body and rotatably supports the moving member in a horizontal direction, wherein the linear motor mechanism includes a shaft body. 2. The material testing machine according to claim 1, comprising a plurality of thrust magnets disposed on the base along the axis and an electromagnetic coil incorporated in the moving member. 3. 4. The air bearing introduces compressed air between an inner surface of a bearing portion of the moving member surrounding the shaft and a side surface of the shaft, and moves the moving member along the shaft. The compressed member is lifted by introducing compressed air to a pedestal provided opposite to a lower surface of the shaft to maintain a non-contact between the bearing portion and the shaft. 3. The material testing machine according to 2. 5. The material testing machine according to claim 1, wherein the linear motor mechanism is servo-controlled while detecting position information of the moving member with respect to the shaft.