JP2006250865A - Torque detecting device and torque controller using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque detecting device with small size and light weight, high sensitivity, and high precision that can inexpensively manufacture and has little constraints, and high robust performance, and a device utilizing and applying the same. <P>SOLUTION: The device detecting torque applied to a shaft body includes a sensor module 110 that is arranged on the surface of the shaft body 101 and composed of a sensor chip 112 having a detection coil 201 arranged close to a detection plate 111 with a magnetic strain film and the magnetic strain film, and a fixed side module 120 that wirelessly transmits and receives with the sensor module. The sensor module has a plate semiconductor substrate 301, a receiving antenna 211 for receiving electromagnetic waves wirelessly supplied from the fixed side module, and a transmitting antenna 210 for transmitting signals concerning the detect torque to a fixing section. The transmitting antenna and the receiving antenna are formed on one surface of the substrate, and the detection coil is formed on the other surface of the substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is suitable for detecting torque in various shafts, gears, pulleys, and other rotating bodies, and is used in products manufactured in large quantities at low cost, and in harsh environments, and has higher reliability and fail-safety. The present invention relates to a torque detection device that can be applied to required vehicles and the like, and a torque control device that uses information about torque output from the torque detection device.

  As a method of measuring the torque of the shaft as an electric signal, a mechanical displacement of the shaft body 607 is detected by a strain gauge 608 as shown in FIG. 6B, or a shaft body machine as shown in FIG. 6C. There is a so-called magnetostrictive torque detecting device that detects the mechanical displacement with the optical sensor 609 and the optical slit 610, or uses the inverse magnetostrictive effect of the magnetostrictive material 601 applied to the surface of the shaft body 602 as shown in FIG. It is common. A typical torque detection principle of the magnetostrictive torque detector will be described with reference to FIGS.

  When the torque T is applied to the shaft body 701, one is compressed in the +45 degree and -45 degree directions with respect to the axial direction of the shaft body 701 as indicated by directions 702 and 703 in FIG. On the other side, stress in the pulling direction is generated. This stress is generated in any part of the shaft.

  Incidentally, a magnetostrictive material having a positive saturation magnetostriction constant has the property that, as shown in FIG. 8, the permeability increases when the material is pulled, and the permeability decreases when the material is compressed. When such a magnetostrictive material 704 is fixed to the surface of the shaft body 701 as shown in FIG. 7, inverse magnetostriction effects are generated in directions of +45 degrees and −45 degrees with respect to the axial direction of the shaft body 701. FIG. 6A shows a specific configuration of the magnetostrictive torque sensor using the inverse magnetostrictive effect. A magnetostrictive material 601 is applied to the surface of the shaft 602, and the magnetostriction on the shaft 602 is applied. The material 601 is provided with elongated slits 603 and 606 at +45 degrees and −45 degrees, respectively, with respect to the axial direction of the shaft body 602, and a detection coil 604 that detects the magnetic characteristics of the magnetostrictive material portion outside the slits 603 and 606. , 605 are arranged. As a magnetostrictive torque detection device using such a magnetostrictive effect, for example, a device in which a film of a magnetostrictive material is provided on the surface of a shaft body and a detection coil is arranged around the shaft is known (for example, Patent Documents). 1).

  As another magnetostrictive torque detection device, the detection coil is arranged in a tilted and opposed manner with respect to the axis, and the detection coil is reduced to a magnetic head type (for example, Patent Document 2, 3), and a mechanical quantity sensor (for example, see Patent Document 4) in which a film-like planar coil is provided on the magnetostrictive layer on the surface of the shaft body to improve sensitivity and temperature characteristics.

  However, the conventional general mechanical displacement detection type torque detection device has many problems in accuracy, structural restrictions and low cost manufacturing, and in particular, the magnetostrictive torque detection device has various problems shown below. The spread is delayed compared to other physical quantity detection sensors.

  For example, the magnetostrictive torque detection device described in Patent Document 1 must have a large axial dimension due to its structure, and an annular detection coil must be passed through the shaft. There are also large restrictions. In addition, since the opposite inverse magnetostriction generation sites are physically separated from each other, there is a problem that if the shaft body has a temperature gradient, the magnetic characteristics are not balanced and a temperature drift occurs in the torque detection characteristics. In order to improve these problems, in the torque detection device described in Patent Document 2 or 3, a magnetic head type torque sensor in which a cross-shaped groove is formed in a magnetic core and an eight-shaped coil is inserted into the groove. It is said.

  These do not require the detection coil to pass through the shaft, and can be mounted at one location around the shaft. Although the temperature drift characteristics are improved because the detector is small, the change in the gap between the shaft and the detection coil core affects the torque detection sensitivity. Therefore, a highly accurate bearing structure and strict gap management are required, and the sensor itself can be downsized. However, there are many restrictions on the structure around the shaft and sensor mounting. In addition, the magnetic head type detection coil requires advanced manufacturing technology, and it has been difficult to manufacture at low cost.

  To improve the above, a film-like planar coil is directly attached to a shaft body having a magnetostrictive material on its surface like the mechanical quantity sensor described in Patent Document 4, and this coil is excited from outside the shaft at different locations on the shaft. Another annular coil is provided to further improve detection sensitivity, sensitivity fluctuation due to a gap, temperature drift, and the like. However, even in the mechanical quantity sensor described in Patent Document 4, it is necessary to pass an annular coil for excitation through the shaft body, and there is a great structural limitation in the assembly of the sensor, and the impedance change of the torque detection unit Is indirectly detected via an annular coil, so there is a limit to the improvement in sensitivity.

  In order to solve the above-mentioned problems, the applicant of the present application has proposed a torque detection device that fixes a torque detection module on a shaft and reads out a torque value with electromagnetic waves. As shown in FIGS. 9A and 9B, this torque detector directly fixes a magnetostrictive material 902 to a groove 901a of a shaft body 901, and a planar coil on a film, a transmission / reception antenna, and signal processing thereon. A shaft-side torque sensor module 903 configured by a chip is arranged, fixed by a fixing ring 904, and power transmission / reception and torque detection value signal transmission by electromagnetic waves are performed by the fixed-side module 905. This proposal detects and processes torque directly on the shaft and transmits the detected value by electromagnetic waves, so it is compact, highly sensitive, and has a high degree of freedom for sensor mounting.

  Further, as a developed form thereof, as shown in FIG. 9C, a power receiving antenna 911 and a signal transmitting antenna 912 are formed on a semiconductor substrate 910, and a detection coil 913 is formed. There is also proposed one in which a signal processing circuit 915 and the like are formed, and the shaft side torque sensor module is a one-chip type. However, both of these have the problem that the magnetostrictive material film must be fixed directly to the shaft surface by vapor deposition, sputtering, etc., and there is a problem that the shaft body manufacturing process is considered and a special film fixing device is required. .

In order to solve the above-mentioned problems, the applicant of the present application proposes an improved material and structure of the shaft body and sensor manufacturing constraints by transmitting the physical displacement of the shaft body once to the detection plate and detecting the torque. did. As shown in FIG. 10, the torque detection device is composed of a sensor module 921 fixed to a shaft 920 and a fixed module 922 disposed in close contact with the sensor module, and the shaft 920, sensor This is a method in which a stationary module 921 composed of a chip 923 and a detection plate 924 with a magnetostrictive film is separately manufactured and joined together. According to this method, the machining technique conventionally performed on the shaft can be used as it is, and the manufacturing, distribution and management costs of the torque detection device can be reduced. In addition, since this method does not use the magnetic characteristics of the shaft body itself for torque detection, the shaft material has a high degree of freedom and can be applied to nonmagnetic metals, resins, fiber reinforced plastics, and the like. The invention of FIG. 10 also uses a one-chip type sensor 923 in which an antenna, a circuit, and a detection coil are shaped on a semiconductor chip.
Japanese Patent Publication No. 3-26339 JP-A-6-221940 JP-A-10-38714 Japanese Patent Laid-Open No. 7-63627

  However, when the one-chip type sensor 923 is configured in the form of FIG. 9C, the transmitting / receiving antenna and the detection coil are shaped on the same plane on the semiconductor substrate, so that the area that can be used as the detection coil on the chip is extremely small. Furthermore, since the semiconductor substrate is disposed at an angle of 45 degrees with respect to the side of the semiconductor substrate, the chip surface utilization efficiency is poor, the impedance detection sensitivity is lowered, and the torque detection sensitivity is reduced. This means that the chip area is increased at the same time, and the manufacturing yield and the cost of the sensor are increased.

  Further, as shown in FIG. 11, when the chip is arranged with the detection coil 913 facing the magnetostrictive material film, that is, the detection plate with the magnetostrictive film, the transmission / reception antennas 911 and 912 become the detection plate side, and the semiconductor substrate causes the electromagnetic wave to be transmitted. Since attenuation is unavoidable and the antenna approaches the detection plate 930 with a magnetostrictive film, which is a metal, the electromagnetic wave 931 is attenuated, and the power and signal transmission / reception performance deteriorates.

  Moreover, in order to improve the detection sensitivity, more current must be passed through the detection coil, and as a result, the power of the electromagnetic wave 931 supplied from the outside to the torque sensor as a power source must be increased. These generally have an adverse effect on other electronic devices, increase the price of the torque detection device, and become an obstacle to practical use. Further, since only one set of detection coils is provided, there is a problem that the function of the entire sensor is lost when one of the coils or the impedance detection circuit fails.

  The present invention has been made in view of such problems, and the object of the present invention is to be small, lightweight, highly sensitive, highly accurate and inexpensive to manufacture, with few mounting restrictions, and with low power. An object of the present invention is to provide a torque detector that can be driven, can follow the conventional manufacturing process as it is, and has good robustness. Moreover, it is providing the control apparatus which uses the information regarding the torque output from this torque detection apparatus.

  As a result of intensive studies on the torque detection device, the present inventors have completed the present invention having the following characteristics. That is, the torque detection device according to the present invention uses both sides of a one-chip type semiconductor substrate, one side is the detection coil side, the other side is the antenna and circuit side, and the detection coil and the signal processing circuit penetrate both sides of the chip. The detection coil can be arranged on the entire surface of one side of the chip by being electrically connected by the through via.

  Further, the sensor chip is arranged in advance and in parallel to the chip side by arranging the sensor chip itself in an axial direction of the shaft body and the chip side at an angle of 45 degrees. Further, a plurality of detection coils arranged in pairs with two coils arranged at an angle of 90 degrees are provided, and these faults are detected and separated for each coil pair to correct the torque detection value. By detecting and transmitting torque and transmitting information on the failed part, correction can be performed on the receiving side as well.

  Specifically, a torque detection device according to the present invention includes a sensor unit that is disposed on the surface of a shaft body and includes a magnetostrictive material and a detection coil that is disposed in proximity to the magnetostrictive material, and the sensor unit wirelessly. A device for detecting torque applied to the shaft body, wherein the sensor unit includes a plate-like substrate and receives an electromagnetic wave supplied wirelessly from the fixed unit. And a transmission antenna that transmits a signal related to the detected torque to the fixed portion, the transmission antenna and the reception antenna are formed on one surface of the substrate, and the coil is It is formed on the other surface of the substrate. In particular, the detection coil is preferably disposed on the surface facing the shaft body, and the reception antenna and the transmission antenna are preferably disposed on the opposite surface facing the fixed portion.

  The torque detection device of the present invention configured as described above can improve the transmission / reception performance because the transmission antenna and the reception antenna are formed on one surface of the substrate and the detection coil is formed on the other surface. In addition, since the detection coil that is formed on the other surface of the substrate and detects the impedance change of the magnetostrictive material deformed by the application of torque can be formed large, the torque detection sensitivity can be improved.

  As a preferred specific aspect of the torque detection device according to the present invention, the sensor section detects an impedance change of the detection coil, and converts the detected impedance change into torque information by signal processing. A signal processing circuit, a transmission circuit that modulates and amplifies a signal related to torque information and transmits a radio wave, and a reception circuit that receives an electromagnetic wave transmitted from the fixing unit are provided. The torque detection device configured as described above includes a detection coil for detecting a change in impedance of a magnetostrictive material on one surface on a plate-like substrate, and an impedance detection circuit, a signal processing circuit, a transmission circuit, and a reception circuit on the other surface. In addition, a transmission antenna and a reception antenna can be formed, and various circuits, coils, antennas, and the like can be efficiently arranged on a one-chip substrate.

  Moreover, as a preferable specific aspect of the torque detection device according to the present invention, the substrate has a through-hole connecting the front surface and the back surface, the detection coil formed on one surface, and the other The impedance detection circuit formed on the surface is electrically connected through the through hole. According to this configuration, for example, a transmitting antenna, a receiving antenna, various electric circuits and the like formed on the front surface of the module substrate constituting the sensor unit of the torque detection device, and an electric element such as a detection coil formed on the back surface side Can be easily connected.

  Furthermore, as another preferable specific embodiment of the torque detection device according to the present invention, the detection coil is formed in a plane on the surface of the substrate, and a plurality of parallel or perpendicular to the outer periphery of the substrate. A reciprocating coil comprising a parallel pattern and cross patterns alternately connecting ends of the plurality of parallel patterns is formed, and a coil pair is formed by using two detection coils. It is characterized in that one end thereof is connected so as to be orthogonal. According to this configuration, the coil that detects torque as an impedance change is formed from the parallel pattern and the intersecting pattern that connects the ends of the parallel pattern, and can be easily formed. Since the impedance can be detected, the detection sensitivity can be increased.

  As another preferred specific aspect of the torque detection device according to the present invention, a plurality of the coil pairs are arranged, and a total torque calculation circuit that selects or averages signals related to torque output from the plurality of coil pairs is provided. It is characterized by. According to this configuration, a plurality of coil pairs are arranged, and the total torque is calculated by selecting or averaging using the signals related to the torque output from the plurality of coil pairs, so that accurate torque detection is possible. Become.

  As another preferable specific aspect of the torque detection device according to the present invention, the torque detection device includes a failure detection means for detecting a failure of the plurality of coil pairs, and the torque output from the coil pair detected by the failure detection means. And a correction circuit that corrects a signal output from the plurality of coil pairs. According to this configuration, a failure of a plurality of coil pairs that detect impedance changes is detected, and signals from the coil pairs are disconnected and invalidated by a circuit, or signals output from the plurality of coil pairs are corrected. Therefore, accurate torque detection is possible.

  As another preferred specific aspect of the torque detection device according to the present invention, the transmission antenna transmits information on impedance changes or torque detected from a plurality of coil pairs, respectively. According to this configuration, correction of torque information output from the plurality of coil pairs, failure detection, and loss of function of the torque detection device at the time of failure can be prevented.

  In the torque detection device according to the present invention, it is preferable that the plurality of coil pairs are constituted by two reciprocating coils arranged apart from each other. That is, two non-adjacent coils are connected to form a coil pair. According to this configuration, since the two reciprocating coils constituting the coil pair are separated from each other without being adjacent to each other, it is possible to eliminate variations when forming the coils in a plane and to detect the impedance change with high accuracy. be able to.

  The torque control device according to the present invention is characterized in that torque is controlled using information on torque output from any of the torque detection devices described above. According to this configuration, torque of various rotating shafts and the like can be detected with high accuracy, and the configuration is simple, so that the control device can be reduced in size. Moreover, since the accuracy of the detected torque is good, the function of the control device can be stabilized.

  Even if the torque detection device according to the present invention is a one-chip sensor having a torque detection function and a power / signal transmission / reception function on a semiconductor substrate, the entire surface of one side of the substrate can be used as a detection coil. Torque detection sensitivity can be improved without increasing the power, and power can be saved.

  In addition, since the power supply and signal transmission / reception antenna and the detection coil are arranged on different surfaces on the substrate, and the antenna can be arranged on the outer side and the coil on the shaft side, interference between the detection coil and the transmission / reception electromagnetic wave can be reduced. Further, since the shaft and the detection plate, which are often made of metal, can be moved away from the antenna, the gain of the antenna can be improved.

  By providing multiple pairs of detection coils for torque detection and dispersing them on the substrate, it is possible to reduce the effects of material variations and film formation variations of the magnetostrictive material film, and improve torque detection accuracy and product yield. . Furthermore, it is possible to prevent complete loss of function even if a failure occurs in a part of the sensor by detecting a failure in a plurality of dispersed detection coils and circuits and correcting the signal by separating the failure portion. . This improves the robustness of the sensor and can be applied to applications that require high reliability.

[First Embodiment]
Hereinafter, a first embodiment of a torque detection device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a main part perspective view showing a basic configuration of a torque detection device according to the present embodiment, and FIG. 1A is a main part perspective view in a state where a shaft body to which a sensor module is fixed and a fixed side module are separated from each other. And (B) is a perspective view of the main part with a part of the shaft body that detects torque being broken, and (C) is a perspective view of a state where torque in one direction is applied to the shaft body. (D) is a perspective view and a main part enlarged view of a state in which torque in the other direction is applied to the shaft body, and FIG. 2 is a block diagram showing an electrical configuration of the sensor chip and the fixed side module of FIG. 3A and 3B show the configuration of the main part of the sensor chip, FIG. 3A is a schematic perspective view, FIG. 3B is a front view with a part omitted, FIG. 3C is a cross-sectional view of the main part, and FIG. It is.

  In FIG. 1, a torque detection device 100 according to the present embodiment is fixed to a shaft body 101 that is a torque detected body, a sensor module 110 that rotates integrally with the shaft body, and a fixed side that is fixed separately from the shaft body. The module 120 is configured so that the sensor module and the stationary module function as a pair. This basic configuration is the same as the configuration shown in FIG. 10 described in the related art. FIG. 1 shows a mounting form on a shaft 101 of a one-chip type torque sensor chip using the present invention.

  The sensor module 110 is fixed on mounting seat surfaces 103 and 104 that are flatly processed so as to straddle the groove 102 formed in the circumferential direction in the shaft body 101. With this configuration, a minute displacement is generated on the mounting seat surface divided by the groove when torque is applied to the shaft body. The sensor module 110 is fixed to the shaft body 101 which is a torque detected body and rotates integrally with the shaft body 101.

  The sensor module 110 includes a detection plate 111 made of a metal plate having an X-shaped central portion and a sensor chip 112 described later, and the sensor chip 112 is fixed to the surface of the detection plate 111. The detection plate 111 has an X-shaped portion at the center, and the X-shaped portion is formed to be +/− 45 degrees with respect to the axis. The detection plate 111 has both sides fixed to the mounting seat surface of the shaft by welding or the like, and stress due to the minute displacement is generated in the detection plate 111 according to the minute displacement caused by applying torque to the shaft body. The relationship between the application of torque to the shaft body and the stress generated in the detection plate 111 will be described.

  As shown in FIG. 1C, when the torque + T is applied to the shaft body 101, a minute displacement corresponding to the torque is generated by the elastic force of the shaft body. Since both ends of the detection plate 111 are firmly fixed to the seating surface by welding or the like, the displacement of the seating surface generates a compressive stress 105 and a tensile stress 106 in the X-shaped portion of the detection plate 111, respectively. Next, as shown in FIG. 1D, when the opposite side torque -T is applied to the shaft body 101, the X-shaped portion of the detection plate 111 in this case generates tensile and compressive stresses in the opposite direction. These are contradictory compressive and tensile stresses of +/− 45 degrees with respect to the axial direction, and are the same as the relationship between the stresses generated on the shaft surface described above with reference to FIGS.

  Therefore, if the magnetostrictive material is fixed to the X portion central surface of the detection plate 111 in a film shape, or the detection plate itself is made of a magnetostrictive material, and the impedance change due to the inverse magnetostriction effect on the X surface central surface of the detection plate 111 is measured. The torque of the shaft body 101 can be detected. In the illustrated example, the sensor chip 112 is exposed for the sake of explanation. However, as a more practical embodiment, it is desirable to mold a part thereof with a resin or the like.

  The fixed-side module 120 has an opening larger than the diameter of the shaft body 101, and has a horseshoe-shaped housing along the outer periphery of the shaft body. The opening has a semicircular arc surface and can be opposed to the shaft body with a predetermined gap. The gap is preferably about 1 mm, but is not particularly defined. That is, there is an advantage that the smaller the gap is, the less power is transmitted and received. When detecting the torque of the shaft body, it is only necessary to move the opening along the outer peripheral surface of the shaft body. There are almost no restrictions on installation, and power is transmitted from the fixed module and signals from the sensor module. Can be transmitted stably.

  FIG. 2 shows the sensor chip 112 and the stationary module 120 from an electrical point of view. The sensor chip side has an inverse magnetostrictive effect generated on the axis, that is, a surface indicated by directions 702 and 703 in FIG. A detection coil 201 for detecting a change in permeability due to stress as an impedance change, a resistor 202 for forming a bridge circuit, two excitation coils are excited, and a contradictory impedance between the detection coils is differentially amplified to generate a torque. An excitation / impedance detection circuit 203 for extracting information, a signal modulation circuit 204 for transmitting torque information by radio waves, a signal processing circuit 206 comprising a high frequency amplification circuit 205 for amplifying the modulated torque signal and sending it to an antenna, Transmitting antenna 210 for transmitting from the shaft side to the outside, power receiving for receiving radio waves for power Sensor chip formed with an antenna 211, a power receiving circuit 212 that converts electric power received as radio waves into a circuit power source, and a reference signal discriminating circuit 213 that receives a reference signal necessary for a series of signal processing and modulation and supplies the reference signal to each part 112 is fixed to the detection plate 111 coated with a magnetostrictive film and rotates integrally with the shaft 101.

  The sensor chip 112 is formed from, for example, a single silicon substrate. The detection coil 201 detects a change in inductance in which the excitation state changes due to stress as a change in impedance of the bridge circuit. As the bridge circuit, an appropriate form such as a full bridge circuit or a half bridge circuit can be used, but a full bridge circuit is preferable in terms of sensitivity. Further, instead of the inductance change, another characteristic change may be detected.

  On the other hand, the fixed module 120 includes a reference signal generation circuit 220 that generates a reference signal to be transmitted to the sensor chip 112, a power source and a power transmission circuit 221 that transmits the reference signal to the shaft side as an electromagnetic wave, and a power source that emits these as radio waves. Transmitting antenna 222, signal receiving antenna 223 for receiving radio waves transmitted from the shaft side, high frequency amplifier circuit 224 for amplifying weak radio waves received by the antenna, signal demodulating circuit 225 for extracting torque signals from radio waves, torque signals A signal output circuit 226 for outputting to the outside is provided.

  FIG. 3 is a diagram showing a first embodiment of the sensor chip of the torque detection device according to the present invention. For example, the sensor chip 112 of the torque detection device 100 of FIG. 1 will be described. Usually, there are two processed surfaces available on the semiconductor chip on the semiconductor substrate 301. For example, when one side is defined as the front surface, the opposite side is the back surface. A signal processing circuit 206, a signal transmission antenna 210, a power reception circuit 212, and a power reception antenna 211 are formed on the surface. On the other hand, two detection coils 201 whose longitudinal directions are 90 degrees each other are processed as a set on the back surface, and compressive and tensile stresses generated in the magnetostrictive material film fixed on the detection plate are detected as impedance changes. .

  The detection coil 201 is formed in a plane on the surface of the substrate, and includes a plurality of parallel patterns that are parallel or perpendicular to the outer periphery of the substrate 301 and a cross pattern that alternately connects the ends of the plurality of parallel patterns. It is formed in the reciprocating coil which consists of. In FIG. 3D, a coil pair is formed by connecting one end of a detection coil having a horizontal parallel pattern and a detection coil having a vertical pattern. The detection coil 201 can be arranged on the entire back surface of the substrate at the maximum, but other circuits or wirings may be processed for another purpose. The detection coil 201 processed on the back surface and the signal processing circuit 206 processed on the front surface are electrically connected by providing a through via 302 as a through hole penetrating the front surface and the back surface of the semiconductor substrate. In addition, you may connect the electrical connection of front and back using another method.

  In the first embodiment configured as described above, the electromagnetic wave 230 for power transmitted from the power transmitting circuit 221 of the fixed module 120 by the transmitting antenna 222 is received by the receiving antenna 211 of the sensor chip 112 and detected. The coil 201 is excited to bring the sensor chip into an operating state. When torque is applied to the shaft body 101 and stress acts on the detection plate 111 of the sensor chip, the impedance of the detection coil changes due to the inverse magnetostrictive effect. This impedance detection value is processed by the signal modulation circuit 204, amplified by the high frequency amplification circuit 205, transmitted from the transmission antenna 210 to the stationary module 120 by the electromagnetic wave 231, and received by the signal reception antenna 223.

  Since the detection coil 201 is formed on the back surface side of the substrate 301, and the reception antenna 211 and the transmission antenna 210 are formed on the front surface side of the substrate 301, there is little mutual interference, the transmission / reception function is stable, and accurate Torque can be detected. In addition, the sensor chip 112 can be made small and light, and the fixed-side module 120 has one end opened so as to be easily opposed to the sensor chip. However, it can be easily attached and an accurate torque can be detected. Furthermore, since the electromagnetic waves transmitted and received are not easily attenuated, power saving can be achieved.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIG. In FIG. 9C, FIG. 11 and FIG. 3, there is one set of detection coils. However, as shown in FIG. 4A, 0 torque detection is possible even if this is divided into a plurality of blocks and arranged alternately in a grid pattern. Does not affect the principle. In the example shown in the drawing, 16 reciprocating coils having a parallel pattern and an intersecting pattern connecting the ends of the parallel pattern are formed, and a horizontal pattern coil and a vertical pattern coil are connected to form 8 reciprocating coils. Coil pairs can be formed. With this configuration, various arrangements of the detection coil 201 are possible. For example, if all the detection coils 201 whose horizontal directions are horizontal are connected in series and used as a single detection coil, the material variation of the magnetostrictive material film fixed on the detection plate 111 and the detection torque due to film formation variation It is possible to reduce the offset error.

  This is because when the torque is not applied to the shaft body 101 and the impedances of the two detection coils are not balanced, the torque is applied in either direction. Yes, this occurs due to variations on the magnetostrictive material side and circuit imbalance components. Therefore, for example, when the film formation state of the magnetostrictive material film on the detection plate 111 is not uniform, the arrangement of two single detection coils 201 having a large area is more susceptible to film formation variations. For this reason, if a plurality of small detection coils are dispersed and arranged in a lattice pattern and alternately, unbalanced components due to variations in the magnetostrictive material film are dispersed, and offset errors under the same film forming conditions are reduced. Can do. In this embodiment, the pair of detection coils may be a pair of detection coils 401 arranged apart from each other without being adjacent to each other. Thereby, the variation can be further reduced.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIGS. 4B and 4C. If the detection coil 201 divided into a plurality of blocks in the above-described embodiment includes a detection coil 403 that forms a pair with a non-functional detection coil 402, the coil pair is separated and invalidated. That is, when individual impedance detection circuits 404 are provided for a plurality of coil pairs, and the coil failure detection circuit 405 that monitors each circuit or coil abnormality determines that either the detection coil 201 or the impedance detection circuit 404 is defective. The faulty system is disconnected by the disconnection circuit 406, and the total torque calculation circuit 407 selects or averages signals relating to effective torque to calculate the total torque. At the same time, if the correction circuit 408 is adjusted based on the output of the failure detection circuit 405, the function as a torque sensor can be continued. This correction may be performed after calculating the total torque or may be performed on other signal paths. Further, this separation may be based on other failure parts, and the correction contents are not limited by this embodiment.

  In addition, if there is sufficient torque detection performance in advance for the desired torque detection sensitivity, or if a spare coil is placed, even if there is a manufacturing defect in the sensor chip or magnetostrictive material film, this part Since the desired functions and performances can be satisfied by separating and replacing, the manufacturing yield can be improved and the robustness can be improved. That is, even if a certain coil pair breaks down, it can be backed up using another coil pair, and the function can be restored.

[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, the sensor chip 112 fixed on the shaft body 101 receives the electromagnetic wave for power supply as the electromagnetic wave 231, receives the torque information transmitted as the electromagnetic wave 230 by the fixed side module 120, and from the fixed side module, It shows a form transmitted to a control device 501 or a measuring device that uses torque information by serial communication. If the communication frame of this serial communication is configured as shown in FIG. 5B with the detection coil or circuit or other diagnostic information 505 and the torque information 506 described in the third embodiment, the torque information can also be obtained on the control device 501 side. Correction, failure detection, and prevention of loss of function at the time of failure. The diagnostic information is, for example, information for specifying a failed coil pair, and the correction circuit 408 is corrected based on this information.

  As another method, as shown in FIG. 5C, according to each detection coil 201, the torque information following the diagnostic information 505 is individually transmitted as in 507 to 509, and the diagnostic information 505 is changed. On the basis, the same effect can be obtained even if the use determination or correction of the torque information frames 507 to 509 detected from the plurality of coil pairs is performed. Thus, even if a failure such as disconnection occurs in the detection coil, the failure portion can be separated and functioned, so that the yield of the sensor chip and the robustness of the control device can be improved.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed. For example, the detection plate constituting the sensor unit is preferably made of a metal plate material, but is not limited to metal, and may be made of plastic or ceramic.

  Further, the shaft body for detecting the torque is not limited to a metal, but can be applied to a plastic shaft. When the shaft body is made of plastic, the detection plate of the sensor module can be fixed by insert molding when the shaft body is formed.

  As an example of use of the present invention, by attaching this torque detection device to a plurality of rotating shafts, torque management of rotating shafts such as a crankshaft of an automobile engine, a drive shaft of a transmission, a drive shaft for driving wheels, and the like is performed. It can also be used for controlling purposes. In addition, the torque of the power steering shaft of the automobile can be easily detected, and can be used for detecting the torque of the arm of the robot apparatus and various applications, and the torque control apparatus can be configured using the detected torque.

The basic structure of 1st Embodiment of the torque detection apparatus which concerns on this invention is shown, (A) is a principal part perspective view of the state which separated the shaft body which fixed the sensor module, and the stationary-side module, (B) is The main part perspective view which fractured | ruptured a part of shaft which detects a torque, (C) is the state and perspective view and principal part enlarged view which applied the torque of one direction to the shaft, (D) is another direction to a shaft The perspective view of the state which applied the torque of, and the principal part enlarged view. The block diagram which shows the electrical structure in the sensor chip of FIG. 1, and the electrical structure of a stationary-side module. FIG. 1 shows a configuration of a main part of a sensor unit of the torque detection device shown in FIG. 1, (A) is a schematic perspective view, (B) is a partially omitted surface view, (C) is a cross-sectional view of the main part, (D). Is a back view. (A) is a plan view showing the detection coil of the second embodiment, (B) is a plan view showing the detection coil of the third embodiment, (C) is a connection of the detection coils of (A) and (B). Block diagram. (A) is a figure which shows the structure of the control apparatus using the torque detection apparatus of this invention as 4th Embodiment, (B) is explanatory drawing which transmits the signal from a torque detection apparatus to a control apparatus, (C) Is another explanatory diagram of transmitting a signal. The figure which shows the conventional torque detection apparatus. The principle explanatory drawing which detects axial torque by the inverse magnetostriction effect of a magnetostrictive material. FIG. 5 is a relationship diagram of stress and permeability of a magnetostrictive material having a positive saturation magnetostriction constant. The other example of a prior art is shown, (A) is a perspective view of a disassembled state, (B) is a perspective view of an attached state and a perspective view after attachment, (C) is a perspective view of a sensor chip. The perspective view which shows the other conventional torque detection apparatus. The figure which shows description of the technical subject which should take countermeasures of the torque detection apparatus of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Torque detection apparatus, 101 ... Shaft body, 105, 106 ... Stress which generate | occur | produces on the shaft body surface, 110 ... Sensor module (sensor part), 111 ... Detection plate with a magnetostrictive film, 112 ... Sensor chip, 120 ... Fixed side module (Fixed portion), 201 ... detection coil, 203 ... excitation, impedance detection circuit, 205 ... high frequency amplifier circuit (transmission circuit), 206 ... signal processing circuit, 212 ... power supply reception circuit, 210 ... signal transmission antenna, 211 ... power supply Receiving antenna, 212 ... power receiving circuit, 230, 231 ... electromagnetic wave, 301 ... semiconductor substrate, 302 ... through via (through hole), 401 ... pair of detection coils, 402 ... non-functional detection coil, 403 ... separated Paired detection coils, 404... Impedance detection circuit, 405... Failure detection circuit, 406. Overall torque calculation circuit, 408 ... correction circuit, 501 ... control unit, 505 ... diagnostic information frame, 506, 507, 508, and 509 ... torque information frame

Claims (9)

A sensor unit that is disposed on the surface of the shaft body and includes a magnetostrictive material and a detection coil that is disposed in proximity to the magnetostrictive material, and a fixing unit that wirelessly transmits and receives the sensor unit, and is applied to the shaft body A device for detecting the generated torque,
The sensor unit includes a plate-like substrate, and includes a receiving antenna that receives an electromagnetic wave wirelessly supplied from the fixed unit, and a transmission antenna that transmits a signal related to the detected torque to the fixed unit. ,
The transmitting antenna and the receiving antenna are formed on one surface of the substrate, and the detection coil is formed on the other surface of the substrate.   The sensor unit includes an impedance detection circuit that detects an impedance change of the detection coil, a signal processing circuit that converts the detected impedance change into torque information, and modulates and amplifies a signal related to the torque information to generate a radio wave The torque detection device according to claim 1, further comprising: a transmission circuit that transmits and a reception circuit that receives an electromagnetic wave transmitted from the fixing unit.   The substrate has a through hole connecting the front surface and the back surface, and the detection coil formed on one surface and the impedance detection circuit formed on the other surface are electrically connected through the through hole. The torque detection device according to claim 2, wherein the torque detection device is connected to the torque detection device. The detection coil is planarly formed on the surface of the substrate, and includes a plurality of parallel patterns that are parallel or perpendicular to the outer periphery of the substrate and a cross pattern that alternately connects ends of the plurality of parallel patterns. Formed in a reciprocating coil
The torque according to any one of claims 1 to 3, wherein two detection coils are used to form a coil pair, and one end of the coil pair is connected so that the parallel patterns are orthogonal to each other. Detection device.   The torque detection device according to claim 4, further comprising: a total torque calculation circuit that arranges a plurality of the coil pairs and selects or averages signals related to torque output from the plurality of coil pairs.   A disconnection circuit that includes a failure detection unit that detects a failure of the plurality of coil pairs and invalidates a signal related to torque output from the coil pair detected by the failure detection unit and / or an output from the plurality of coil pairs The torque detection device according to claim 4, further comprising a correction circuit that corrects a signal to be transmitted.   The torque detection device according to claim 4, wherein the transmission antenna transmits information related to an impedance change or torque detected from the plurality of coil pairs.   The torque detection device according to any one of claims 4 to 7, wherein the plurality of coil pairs are configured by two reciprocating coils arranged apart from each other.   A torque control device that controls torque using information about torque output from the torque detection device according to any one of claims 1 to 8.

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