JP6639097B2 - Temperature detector and temperature detector - Google Patents

Description

  The present invention relates to a temperature detector and a temperature detector suitable for detecting a temperature near a power supply coil of a non-contact power supply device.

  Conventionally, as a temperature sensor, a thermistor, a thermocouple, a thermosensitive resistance wire, and the like have been widely used. Thermistors are the most widely used and many types are commercially available. Further, as a temperature sensor using a heat-sensitive resistance wire, for example, those described in Patent Documents 1 to 5 are known.

  Patent Literature 1 describes a temperature measuring element in which a coated copper fine wire (0.03 mm) is wound on a surface of a support such as a rod to form a copper resistor, which is covered with a heat conductive film (epoxy resin). .

  Patent Documents 2, 3, and 4 disclose that a thin resistance wire composed of a material having a large temperature coefficient is spirally wound into a disk and a single layer, which is coated with a plastic insulating material such as a synthetic resin to form a film. A temperature resistor formed on a thin flat plate piece is described.

  Patent Literature 5 describes a thermosensitive element for a resistance thermometer in which a thermosensitive resistance band or a thermosensitive resistance wire is wound around a side surface of a cylinder such as bakelite paper and the surface thereof is covered with an insulating paint.

JP-A-57-63429 Japanese Patent Publication No. 12-000695 Japanese Patent Publication No. 120476 Japanese Patent Publication No. 120213 The specification of Jitsumei 361930

  2. Description of the Related Art In recent years, a non-contact power supply device (non-contact power supply device) has been developed as a power supply device for a portable terminal device such as a telephone handset, a mobile phone, a smartphone, and the like, an electric toothbrush, a cleaning robot, an electric vehicle, and the like. In a non-contact power feeding device, a power receiving device (portable device or the like) is detachably attached to the power feeding device, an AC current is fed to the power feeding coil on the power feeding device side, and a power receiving coil is provided on the power receiving device side for magnetic resonance coupling with the power feeding coil. Power is supplied to the power receiving device by generating a floating current in the power receiving coil by the AC current in the power feeding coil.

  In such a non-contact power feeding device, when a conductive foreign object such as a metal is placed near a power feeding coil of the power feeding device in a state where the power receiving device is detached from the power feeding device, an alternation from the power feeding device is caused. An eddy current is generated in the conductive foreign object by the magnetic field, and generates heat. Therefore, in order to prevent an accident such as a fire, a foreign substance detection mechanism for detecting a conductive foreign substance is indispensable. This is particularly important for a non-contact power supply device that supplies a large amount of power, such as a non-contact power supply device of an electric vehicle.

  As one of the foreign matter detection mechanisms, a method of detecting a temperature rise that occurs when the conductive foreign matter generates heat can be considered. In order to detect a temperature rise, it is necessary to arrange a temperature sensor near the power supply coil and detect the temperature rise with the temperature sensor.

  As a temperature sensor, we conducted an experiment to measure the temperature near the power supply coil using a commercially available thermistor, and an alternating magnetic field from the power supply coil generated an induced current in the thermistor. Generated heat, and normal temperature detection was not possible. A similar phenomenon was observed when a thermocouple was used as a temperature sensor. Also, when the temperature measuring element, the temperature resistor, and the thermal element for a resistance thermometer described in Patent Documents 1 to 5 are used, the same phenomenon occurs, and normal temperature detection cannot be performed.

  Therefore, an object of the present invention is to provide a temperature detecting body and a temperature detecting device capable of accurately detecting a temperature near a power feeding coil of a non-contact power feeding device.

A first configuration of the temperature detector according to the present invention includes a strand bundle in which at least two strands of a conductor whose electric resistance changes in temperature are bundled in a state of being insulated from each other,
In the element bundle, two elements among the elements constituting the element bundle are set as detection lines L ₁ and L ₂ , and the detection lines L ₁ and L ₂ are short-circuited at their ends.
A connection terminal for resistance detection is provided on the base end side of the detection lines L ₁ and L ₂ .

According to this configuration, the wire bundle in which the plurality of wires are bundled has a folded structure in which the distal ends of the _two detection lines L ₁ and L ₂ are short-circuited, and the electrical resistance is measured at the base end side. Because of the structure provided with the connection terminals, the opening area of the circuit loop formed by the detection lines L ₁ and L ₂ is substantially zero, and the induced voltage is canceled by going back and forth. Therefore, magnetic flux passing through the circuit loop made by the detection lines L _1, L ₂ are almost negligible, and because the induced voltage is also canceled as occurs, even if an external alternating magnetic field is strong, the detection line L _1, the circuit loop produced by L ₂ no induced voltage is almost. Therefore, since no induced current is generated when detecting the resistance between the connection terminals, the temperature rise of the temperature detector due to the induced current can be ignored, and even in an environment where there is a strong alternating magnetic field from outside, accurate detection is possible. Temperature detection becomes possible.

  A second configuration of the temperature detector according to the present invention is characterized in that, in the first configuration, each of the strands in the strand bundle is twisted with each other.

  According to this configuration, by twisting the respective wires constituting the wire bundle with each other, even if there is a loop through which an external magnetic flux passes due to a small gap between the two wires constituting the wire bundle, the twisting is performed. Since the direction of the loop with respect to the direction of the external magnetic flux is alternately reversed by the matching, the induced voltage due to the interlinkage magnetic flux cancels out between the adjacent inverted loops. Therefore, the generation of induced voltage is almost completely suppressed as a whole, and more accurate temperature detection is possible even in an environment where an external alternating magnetic field exists.

  A third configuration of the temperature detector according to the present invention is the temperature detection device according to the first or second configuration, wherein the wire bundle is spirally wired or filled in a predetermined plane so as to fill a predetermined annular plane. Are wired in a zigzag or meandering shape so as to fill the space.

  According to this configuration, even when the temperature detection range is an area that is spread in a plane, it is possible to detect a partial temperature change in the area by installing the temperature detector in that area. it can. For example, in a non-contact power supply device, a power supply coil and a power receiving coil face each other across a surface having a certain area (hereinafter, referred to as a “magnetic field emission surface”), and a magnetic circuit is formed through the magnetic field emission surface. You. Therefore, when a foreign substance such as a metal is placed on the magnetic field radiation surface when there is no power receiving coil, the foreign substance generates heat and a part of the magnetic field radiation surface partially rises in temperature. Therefore, by installing a temperature detector on this magnetic field emission surface, this partial temperature rise can be detected.

  Here, the “predetermined surface” is a surface that covers a range in which temperature detection is performed, and its shape is not particularly limited. "Wiring to fill a predetermined plane" does not necessarily mean that the wiring is filled without gaps, and even if there are some gaps, the predetermined plane is filled with the element bundle when viewed as a whole. I just need. Further, the wire bundle does not necessarily have to be filled in one layer, and the wire bundle may be wired so as to fill a predetermined plane in a state where the wire bundle overlaps with two or more layers. As an example of “wiring to fill a predetermined surface”, for example, a wire bundle is spirally wired to fill a circular, triangular, rectangular or polygonal surface, or a zigzag or meander. It can be wired in a shape (conformity).

  In a fourth configuration of the temperature detector according to the present invention, in any one of the first to third configurations, the detection wire forming the strand bundle has a wire diameter of 0.2 mm or less. It is characterized by the following.

  According to this configuration, generation of an eddy current in the detection line due to the external magnetic field is suppressed, and a temperature change due to the eddy current generated in the detection line can be prevented. Therefore, more accurate temperature detection becomes possible.

A cable according to the present invention includes a temperature detector having any one of the first, second, and fourth configurations,
The wire bundle is bundled in an insulated state with a current-carrying electric wire or a light-transmitting optical fiber.

  According to this configuration, when an abnormality occurs in a part of the cable and the temperature of the part of the cable locally rises, the resistance value between the resistance detection connection terminals at the cable end is measured to increase the temperature. Can be easily detected.

The coil according to the present invention is a coil in which a current-carrying wire is wound,
A temperature detector having any one of the first, second, and fourth configurations,
The wire bundle is bundled in an insulated state with the conducting wire.

  According to this configuration, when an abnormality such as a disconnection occurs in a part of the energizing electric wire and the temperature of the part of the electric wire in the coil locally rises, the resistance of the temperature detector wound together with the electric wire is reduced. By measuring the resistance between the connection terminals for detection, the temperature rise can be easily detected.

  A temperature detection device according to the present invention includes a temperature detection body having any one of the first to fourth configurations, is connected between two resistance detection terminals, and detects an electric resistance value between the two resistance detection terminals. And a resistance detection circuit that performs the operation.

As described above, according to the present invention, the wire bundle of the temperature detector is configured such that the distal ends of the _two detection lines L ₁ and L ₂ are short-circuited, and the connection terminal for measuring the electric resistance is provided at the proximal end. By setting the opening area of the circuit loop formed by the detection lines L ₁ and L ₂ to be substantially zero, an induced voltage is generated in the circuit loop formed by the detection lines L ₁ and L ₂ due to an external alternating magnetic field. And the temperature rise of the temperature detector due to the induced current can be ignored, and accurate temperature detection is possible even in an environment having an external alternating magnetic field.

  In addition, by twisting each of the wires that compose the wire bundle, the generation of induced voltage is almost completely suppressed as a whole, enabling more accurate temperature detection even in an environment with an external alternating magnetic field. Become.

  Further, by setting the diameter of the detection line to 0.2 mm or less, generation of an eddy current in the detection line due to an external magnetic field can be suppressed, and a temperature change due to the eddy current generated in the detection line can be prevented. Therefore, more accurate temperature detection becomes possible.

FIG. 2 is a perspective view of a temperature detector according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating a strand bundle of FIG. 1. It is a figure showing the relationship of the skin depth with respect to the external magnetic field frequency of copper and aluminum. FIG. 2 is a diagram illustrating a relationship of the strand bundle 2 of FIG. 1 to an external magnetic field. FIG. 4 is a diagram illustrating an example in which the temperature detector according to the first embodiment is installed in a power supply coil of a non-contact power supply device. FIG. 6 is a perspective view of a temperature detector according to a second embodiment of the present invention. FIG. 9 is a perspective view of a temperature detector according to a third embodiment of the present invention. FIG. 13 is a perspective view of a temperature detector according to Embodiment 4 of the present invention. FIG. 13 is a perspective view of a temperature detector according to a fifth embodiment of the present invention. It is a front view of the cable concerning Example 6 of the present invention. It is a front view of the cable concerning Example 7 of the present invention. It is a perspective view of the coil concerning Example 8 of the present invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of the temperature detector according to the first embodiment of the present invention. The temperature detector 1 of the present embodiment winds a wire bundle 2 in which detection wires L ₁ and L ₂ , which are _two fine wire conductors whose electric resistance changes with temperature, are bundled in a state of being insulated from each other. The wire bundle surface filling body 4 is provided. The detection lines L ₁ and L ₂ are short-circuited at the distal end ₂ a, and connection terminals 3 and 3 are provided on the base end sides of the detection lines L ₁ and L ₂ . Further, the two strands L ₁ and L ₂ constituting the strand bundle 2 are twisted with each other.

In the wire bundle 2 wound in a spiral disk shape, adjacent wire bundles are adhered to each other by an adhesive so as not to be scattered. In this embodiment, as the detection lines L ₁ and L ₂ , a copper wire coated with a resin such as an enamel wire is used. However, the temperature coefficient of electric resistance is large enough to easily detect a temperature change. (For example, aluminum, tungsten, etc.). As the connection terminals 3 and 3, crimp terminals such as an R-type crimp terminal and a Y-type crimp terminal, and other electric connectors can be used. Alternatively, the connection terminals 3 and 3 may be formed by peeling off the coating of the base ends of the detection lines L ₁ and L ₂ and solidifying them with solder.

FIG. 2 is a diagram showing the strand bundle 2 of FIG. In FIG. 2A, the strand bundle 2 is configured by twisting each other with the detection lines L ₁ and L ₂ insulated from each other. In FIG. 2, the detection lines L ₁ and L ₂ are one continuous elongated covered conductor, and the covered wire is folded back at the tip 2 a to detect the folded covered wire on both sides with the tip 2 a interposed therebetween. The lines are L ₁ and L ₂ .

The diameter of each of the detection lines L ₁ and L ₂ is set to 0.2 mm or less. Generally, in order to reduce the eddy current generated inside the wire, it is known that the diameter of the wire should be smaller than the skin depth d at which the skin current represented by the following equation (1) occurs. ing. Here, ρ is the electrical resistivity of the conductor, ω is the angular frequency of the current (or the angular frequency of the induced magnetic field), and μ is the absolute magnetic permeability of the conductor.

FIG. 3 shows the relationship between the skin magnetic depth and the external magnetic field frequency of copper and aluminum. Usually, the frequency of the magnetic field used in the non-contact power feeding device is 50 to 200 kHz. Therefore, the skin depth at 200 kHz is about 0.17 mm for a copper wire and about 0.21 mm for an aluminum wire. Therefore, if the diameters of the detection lines L ₁ and L ₂ are set to 0.2 mm or less, the eddy current generated in the detection lines L ₁ and L ₂ due to the external magnetic field can be almost completely suppressed.

Further, since the detection lines L ₁ and L ₂ are folded back, even if an induced voltage is generated when a strong alternating magnetic field is applied from the outside, the detection lines L ₁ and L ₂ are canceled by going back and forth, and are hardly affected by the alternating magnetic field. .

As another configuration example, as shown in FIG. 2B, two covered conductors are used as detection wires L ₁ and L ₂ , which are twisted to form a wire bundle 2, and a detection wire L _{1 is provided at a} tip 2 a thereof. , it is also possible to configure the L ₂ shorted by soldering. In FIG. 2B, in addition to the detection lines L ₁ and L ₂ , unused strands L ₃ and L ₄ are twisted together with the detection lines L ₁ and L ₂ . In the present invention, there may be wires L ₃ and L ₄ not used in this way. FIG. 2B shows an example in which there are two unused strands, but the number of unused strands may be any number. Such unused wires act as heat spreaders. Unused wire in addition to the detection line L _1, L ₂ is a heat conductor, heat transfer in the case of only detecting lines L _1, L ₂ compared to (FIG. 2 (a)), the wayside direction Motosentaba 2 The heat rate increases. Therefore, when one portion of the wire bundle 2 is heated, the heat is quickly diffused to the wire bundle near the heated portion, and the temperature of the wire bundle 2 in a wider range changes. Thereby, the resistance change amount due to the temperature of the detection lines L ₁ and L _{2 as} a whole increases, and the temperature detection sensitivity improves. Also, by bundling unused strands in addition to the detection lines L ₁ and L ₂ , the mechanical strength of the strand bundle 2 is increased, and disconnection is more difficult.

Note that the wire bundle 2 as shown in FIG. 2B can be easily configured using a commercially available litz wire. When the number of unused wires is large, the colors of the coating of the detection wires L ₁ and L ₂ are changed to other unused wires so that the detection lines L ₁ and L _{2 can be} easily distinguished from other unused wires. It is preferable to change the color of the wire coating.

FIG. 4 is a view for explaining the relationship of the wire bundle 2 of FIG. 1 to an external magnetic field. In FIG. 4, for convenience of description, the detection lines L ₁ and L ₂ are shown with a large separation. The detection lines L ₁ and L ₂ are twisted with each other, but when an external magnetic field B is applied, a plane perpendicular to the external magnetic field B (“the magnetic field interlinking plane”) is formed in the gap between the detection lines L ₁ and L _2. "). Since the detection lines L ₁ and L ₂ are twisted, one magnetic field interlinking surface is formed for each twist. As shown in FIG. 4, adjacent magnetic field interlinking surfaces are S ₁ and S ₂ . Since the number of twisted turns of the detection lines L ₁ and L ₂ is substantially constant when viewed locally, the areas of the magnetic-field intersecting surfaces S ₁ and S ₂ can be regarded as substantially constant. The magnetic chain交面S ₁ interlinked local magnetic field (magnetic flux density) B ₁ is a chain, local magnetic field B ₂ is interlinked to the magnetic field chain交面S _2. As long as the alternating magnetic field generated by a normal power supply coil is not very close to the coil, the magnetic field gradient is not large compared to the distance at which the detection lines L ₁ and L ₂ are twisted once, so that the magnetic field B ₁ and the magnetic field B ₂ Can be considered to be approximately equal to Therefore, the magnitude of the magnetic flux linking the magnetic field linkage surfaces S ₁ and S ₂ is S ₁ B ₁ ≒ S ₂ B ₂ . Meanwhile, since the magnetic field chains交面S ₁ and the magnetic strand交面S ₂ is the interlinked direction of the magnetic flux as viewed from the circuit loop of the detection lines L _1, L ₂ has a reversed magnetic field chains交面S an induction current generated in the circuit loop at _1, the induction current generated in the circuit loop in a magnetic field chains交面S ₂ is the opposite direction. Therefore, the two cancel each other out, and no induced current is generated when viewed from the entire circuit loop of the detection lines L ₁ and L ₂ . Therefore, generation of induced voltage is almost completely suppressed as a whole, and more accurate temperature detection is possible even in an environment where an external alternating magnetic field exists.

In the present invention, it is preferable that the detection lines L ₁ and L ₂ are twisted with each other as shown in FIG. 2 to form the wire bundle 2. For example, as shown in FIG. _1, L ₂ and by sufficiently close contact, the external magnetic field that passes through the circuit loop of the detection lines L _1, L _2, if it is possible to sufficiently small that the induced current is negligible, even if not necessarily twisted Good.

  FIG. 5 is a diagram illustrating an example in which the temperature detector 2 according to the first embodiment is installed in a power supply coil of a non-contact power supply device to configure a temperature detection device. The wire bundle surface filling body 4 is used by being attached to the front surface (or the back surface) of the power feeding coil case 5. A power receiving coil (not shown) approaches from above the wire bundle filling member 4, and non-contact power transmission is performed with a power feeding coil (not shown) inside the power feeding coil case 5. When a foreign substance such as a metal piece is placed on the upper part of the power supply coil case 5, an induced current (eddy current) is generated inside the foreign substance due to a magnetic field generated by the power supply coil, and the foreign substance generates heat. The resistance of the temperature detector 1 changes due to this heat, and the resistance change is detected by the resistance detection circuit 6 connected to the connection terminal 3 to detect foreign matter. In addition, power transmission to the power supply coil can be stopped, thereby preventing an accident such as a fire.

  FIG. 6 is a perspective view of the temperature detector according to the second embodiment of the present invention. The temperature detector 1 of this embodiment has basically the same configuration as that of the first embodiment, but the wire bundle surface filling body 4 is sealed and molded by a heat conductive mold resin 7 such as epoxy. The points are different. In this way, by molding, the strand bundle 2 is not scattered, and installation and handling are easy.

  FIG. 7 is a perspective view of a temperature detector according to Embodiment 3 of the present invention. In the temperature detector 1 of the present embodiment, a wire bundle 2 is spirally wound so as to fill a rectangular surface, and a wire bundle surface filling body 4 is formed. The wire bundle surface filling body 4 is sealed in the mold resin 7 as in the second embodiment.

  FIG. 8 is a perspective view of a temperature detector according to Embodiment 4 of the present invention. In the temperature detector 1 of the present embodiment, the wire bundle 2 is wired in a zigzag shape so as to fill a rectangular surface, and a wire bundle surface filling body 4 is formed. The wire bundle surface filling body 4 is sealed in the mold resin 7 as in the second embodiment.

  FIG. 9 is a perspective view of a temperature detector according to Embodiment 5 of the present invention. In the temperature detector 1 of the present embodiment, the wire bundle 2 is wired in a meander shape so as to fill a rectangular surface, and a wire bundle surface filling body 4 is formed. The wire bundle surface filling body 4 is sealed in the mold resin 7 as in the second embodiment.

FIG. 10 is a front view of a cable according to Embodiment 6 of the present invention. A cable 8 in FIG. 10 is a power transmission cable, and a wire bundle 2 including _two detection lines L ₁ and L ₂ is bundled by a sleeve 10 in a state insulated from each other on a current-carrying wire 9. The electric wire 9 and the detection wires L ₁ and L ₂ are litz wires in which a plurality of insulated wires are twisted in a spiral shape, and two adjacent wires among the wires are connected to the detection wire L _1. , it has been used as _{L 2.} The front ends 2a of the detection lines L ₁ and L ₂ are short-circuited, and connection terminals 3 and 3 are provided on the base end sides of the detection lines L ₁ and L ₂ .

  By detecting the resistance value between the two connection terminals 3, 3, the temperature through the entire wire 9 can be detected. For example, even when a temperature rise occurs in a part of the entire section of the electric wire 9, the detection can be performed.

FIG. 11 is a front view of the cable according to the seventh embodiment of the present invention. A cable 8 in FIG. 11 is an optical fiber cable, and a wire bundle 2 composed of _two detection lines L ₁ and L 2 is wound around an optical fiber bundle 11 for light transmission in a state where the wire bundle 2 is insulated from each other. And wound around the sleeve 10 so as not to be scattered. The optical fiber bundle 11 is a bundle of a plurality of optical fibers. The front ends 2a of the detection lines L ₁ and L ₂ are short-circuited, and connection terminals 3 and 3 are provided on the base end sides of the detection lines L ₁ and L ₂ .

  By detecting the resistance value between the two connection terminals 3, 3, the temperature of the entire optical fiber bundle 11 can be detected. For example, if the temperature of a part of the optical fiber bundle 11 rises due to some abnormality, it appears as a change in the resistance value between the two connection terminals 3. This makes it possible to detect any abnormality of the optical fiber bundle 11 in any part.

FIG. 12 is a perspective view of the coil according to the eighth embodiment of the present invention. The coil 12 in FIG.
The cable 8 of the sixth embodiment shown in FIG. 10 (however, the sleeve 10 is omitted in this embodiment) is provided on the side face between the two flanges 13a, 13a of the cylindrical core member 13 having the flanges 13a, 13a formed at both ends. ) Is wound. As described in the sixth embodiment, the cable 8 is a litz wire in which a plurality of insulated wires are twisted in a spiral shape, and two adjacent wires among the wires are detected. They are used as L ₁ and L ₂ . The distal ends 2a of the detection lines L ₁ and L ₂ are short-circuited, and connection terminals 3 and 3 are provided on the base end sides of the detection lines L ₁ and L ₂ .

  This makes it possible to detect the temperature of the electric wire 9 in the coil 12, which is normally difficult to measure, in real time.

DESCRIPTION OF SYMBOLS 1 Temperature detector 2 Wire bundle 2a Tip 3 Connection terminal 4 Wire bundle surface filling material 5 Power supply coil case 6 Resistance detection circuit 7 Mold resin 8 Cable 9 Electric wire 10 Sleeve 11 Optical fiber bundle 12 Coil 13 Core member 13a Flange

Claims (2)

A temperature detector for detecting a temperature in an alternating magnetic field of 50 to 200 kHz,
At least two wires made of a conductor whose electrical resistance changes in temperature include a wire bundle bundled in a state insulated from each other,
In the element bundle, two of the elements constituting the element bundle are set as detection lines L ₁ and L ₂ , and the ends of the detection lines L ₁ and L ₂ are short-circuited. , Each of the detection lines L ₁ and L ₂ is twisted with each other,
A connection terminal for resistance detection is provided on the base end side of the detection lines L ₁ and L ₂ ,
The detection lines L _1, L ₂ constituting the wire bundle, the該検outgoing line L _1, the electrical resistivity of the L ₂ [rho, the absolute magnetic permeability mu, when the angular frequency of the alternating magnetic field omega, the The wire diameter is (2ρ / ωμ) ^1/2 or less ,
The wire bundle is spirally wired so as to fill a predetermined annular surface or is wired in a zigzag or meander shape so as to fill a predetermined surface, and is sealed with a thermally conductive mold resin. Being stopped,
Alternatively, a temperature detector is provided, wherein adjacent wire bundles are spirally wound so as to fill a predetermined annular surface, and adjacent wire bundles are adhered to each other with an adhesive . A temperature detection device comprising: the temperature detection body according to claim 1 ; and a resistance detection circuit connected between the two connection terminals and configured to detect an electric resistance value between the two connection terminals.