JP2006162304A - Torque detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque detector which is small and light, highly sensitive and accurate, and capable of cheaply manufacturing, has no restriction of attachment and can follow conventional production process. <P>SOLUTION: The device is constituted of an axis for transmitting torque and a torque-detecting module which is fixed to the axis rotatably with the axis, receives small displacement generated by twist of the axis as a stress to the module support member, detects and calculates the torque value using the stress and sends the torque information outside of the axis with electromagnetic wave. The device does not utilize the material properties of the axis whose stress detection principle is transmitting the torque or the properties of material fixed as a film on the axis surface, it utilizes the material properties of the module support member or the properties of material fixed as a film on the support member surface. The torque detecting module has a support member of an X shape in part and the torque detection principle is arranged in the center. The main support part of the torque detecting body module is provided with a portion (ear) which is not eventually used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a torque detection device that is suitable for detecting torque in a shaft, gear, pulley, or other rotating body, is inexpensive, and can be adapted for use in a vehicle or the like.

  As a method of measuring the torque of the shaft as an electric signal, a mechanical displacement of the shaft body 807 is detected by a strain gauge 808 as shown in FIG. 8B, or a shaft machine is used as shown in FIG. 8C. There is a so-called magnetostrictive torque detecting device that detects the mechanical displacement with the optical sensor 809 and the optical slit 810, or uses the inverse magnetostrictive effect of the magnetostrictive material 801 applied to the surface of the shaft body 802 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 a torque T is applied to the shaft body, reference numeral 101 in FIG.
As shown by 102, one of the pulling directions is in the + 45 ° and −45 ° directions with respect to the axial direction of the shaft body 104, and the stress in the compression direction is generated in the other. This stress is generated in any part of the shaft.

  By the way, as shown in FIG. 2, a magnetostrictive material having a positive saturation magnetostriction constant has a property that the permeability increases when the material is pulled, and the permeability decreases conversely when the material is compressed. When such a magnetostrictive material is fixed to the surface of the shaft body 104 as indicated by reference numeral 103, an inverse magnetostriction effect is generated in directions of +45 degrees and −45 degrees with respect to the axial direction of the shaft body 104. FIG. 8A shows a specific configuration of the magnetostrictive torque sensor using the inverse magnetostrictive effect. A magnetostrictive material 801 is applied to the surface of the shaft body 802 and the magnetostriction on the shaft body 802 is applied. The material 801 is provided with elongated slits 803 and 806 at +45 degrees and −45 degrees with respect to the axial direction of the shaft body 802, respectively, and a detection coil 804 that detects the magnetic characteristics of the magnetostrictive material portion outside the slits 803 and 806. , 805 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), a torque detection device (see, for example, 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, and a torque detection module is fixed on the shaft body. And what reads a torque value with electromagnetic waves (for example, refer patent document 5) is known.

Japanese Patent Publication No. 3-26339 JP-A-6-221940 JP-A-10-38714 Japanese Patent Laid-Open No. 7-63627 Japanese Patent Application No. 2004-028407

  However, the conventional general mechanical displacement detection type torque detection device has many problems in accuracy, structural restrictions and low cost manufacturing, and 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 it is necessary to pass an annular detection coil through the shaft. There are also great 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 in which a cross-shaped groove is formed in the magnetic core and an eight-shaped coil is inserted in the groove. It is a sensor. 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, a 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 the surface like the torque detection device described in Patent Document 4, and this coil is excited from outside the shaft at different locations on the shaft. There has been proposed another annular coil that is further improved in detection sensitivity, sensitivity fluctuation due to a gap, temperature drift, and the like. However, even in the torque detection device described in Patent Document 4, it is necessary to pass an annular coil for excitation through the shaft body, and there are great structural restrictions on 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.

  A magnetostrictive material is directly fixed as in the torque detection device described in Patent Document 5 and FIG. 9, and a planar coil on a film, a transmission / reception antenna, and a signal processing chip are formed on the magnetostrictive material as described in Patent Document 5 and FIG. It has been proposed that the shaft side torque sensor module 902 is arranged to perform power transmission / reception and torque detection value signal transmission by electromagnetic waves in the fixed side module 905. This proposal detects and processes the torque directly on the shaft and transmits the detected value as an electromagnetic wave. Further, as an advanced form, there has been proposed one in which each antenna and detection coil shown in FIG. 9C are molded on a semiconductor chip to form a one-chip type torque sensor module. However, all of these must fix the magnetostrictive material film directly on the shaft surface by vapor deposition, sputtering, etc., and the general manufacturing process of the shaft body and the process of sputtering, etc., the weight, size, cleanliness of parts There is a problem in that it is far away in terms of the adhering substances and materials such as oil and the like, and the shaft manufacturing method is greatly disregarded and a special membrane fixing device is required. In general, these cause the manufacture of the shaft and the price of the torque detection device, which impede practical use.

  Also, if the shaft must be made of resin, non-magnetic metal, fiber reinforced plastic or other special materials for various reasons, there is a problem in fixing the magnetostrictive material film, or the magnetic properties of the shaft may not be used. Therefore, the inverse magnetostriction effect cannot be used effectively.

  Also, the heat treatment to increase the shaft strength also changes the magnetic characteristics of the shaft, causing problems in torque detection performance and stability, and painting may be necessary for corrosion resistance and design, Even in the method described in Patent Document 5, the characteristics required for the shaft body are generally restricted, and as a result, the application range of the torque detection device is not sufficient.

  The present invention solves these problems, and an object of the present invention is to provide a torque detection device that can be manufactured in a small size, light weight, high sensitivity, high accuracy, and low cost, and that can follow a conventional manufacturing process as it is.

  In order to solve the above problems, a torque detection device according to the present invention is a module that supports a shaft body that transmits torque and a small displacement that is fixed to the shaft body and that can be rotated together with the shaft body and is generated by twisting of the shaft body. It consists of a torque detection module that receives as a member stress, detects and calculates a torque value from this stress, and sends the torque information to the outside of the shaft by electromagnetic waves, and forms a film on the material characteristics of the module support member or on the surface of the support member It is characterized by utilizing the properties of the fixed material.

  The torque detection device according to the present invention does not fix the detection principle directly on the surface of the shaft body or use the magnetic characteristics of the shaft body. It is configured with priority, and the torque detection part is configured to prioritize the torque detection function and does not use the magnetic characteristics of the shaft itself, so the shaft material is highly flexible and non-magnetic metal, resin, fiber reinforced A wide range of applications such as plastic becomes possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 3 is a diagram showing a first embodiment of a torque detection device according to the present invention.

  In the figure, a torque detecting device 300 of this example is fixed to a shaft body 301 that is a torque detected body and is fixed separately from the shaft body 301 and a torque detected body side module 305 that rotates integrally with the shaft body 301. The torque detected body side module 305 and the fixed side module 315 function as a pair.

The torque detected body side module 305 is fixed on mounting seat surfaces 303 and 316 processed into a shaft body. Further, in this embodiment, a groove 302 is formed in the entire radial direction of the torque detection portion, and the seating surface is divided into 303 and 316 by this groove 302, thereby causing a minute displacement due to the applied torque between the seating surfaces 303 and 316. I am doing so. The torque detected object module 305 is a main support member of the sensor module, and includes a detection plate 307 whose central portion has an X shape, and a sensor chip 306 as described in Patent Document 5 and FIG. 9C. The sensor chip 306 is fixed to the surface of the detection plate 307. As shown at 317, the X-shaped portion of the detection plate is arranged to be +/− 45 degrees with respect to the axis. Both ends of the detection plate 307 are fixed to the seating surfaces 303 and 316 by welding or the like, and stress due to the minute displacement is generated in the detection plate 307 according to the minute displacement caused by applying torque to the shaft body. In addition, the shape of the detection plate is as shown in FIG.
Other shapes such as 603 and 603 may be used, and other shapes may be used instead of the X shape.

Next, the relationship between the torque application to the shaft body and the stress generated in the detection plate 307 will be described with reference to FIGS. When a torque + T is applied to the shaft body 304 in FIG. 3B, a minute displacement occurs between the seating surfaces 303 and 316 due to the elastic force of the shaft body. This displacement occurs according to the twist of the shaft, and this displacement increases as the groove 302 becomes deeper. Since both ends of the detection plate 307 are firmly fixed to the seating surfaces 303 and 316 by welding or the like, the displacement of the seating surface generates compression stress in the direction 311 and tensile stress in the direction 312 at the X-shaped portion of the detection plate 307, respectively. To do. Next, when a torque -T on the opposite side is applied to the shaft body 304 as shown in (C), the X-shaped portion of the detection plate 307 is pulled in the direction 311 and a compressive stress is generated in the direction 312. 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, a magnetostrictive material is fixed in the form of a film as shown in FIG. 6 (A) 601 on the surface of the X portion center of the detection plate 307, or the detection plate itself is made of a magnetostrictive material, and the inverse magnetostriction in each of +/− 45 directions By measuring the impedance change due to the effect, it is possible to detect the torque of the shaft body without fixing a magnetostrictive material on the surface of the shaft body or using the magnetic characteristics of the shaft body material. In addition, according to the present invention, the detection plate mounting seat surfaces 303 and 316 and the detection plate can be configured as flat surfaces instead of curved surfaces, so that it is not necessary to change the sensor module for each shaft diameter. As a result, the shaft body only needs to be subjected to general machining, and post-treatment such as quenching and painting can be performed before the sensor module is fixed. Furthermore, it is not necessary to increase the number of types of sensor modules, and the degree of freedom of material of the detection plate is increased, so that the productivity of the shaft body and the torque sensor module 305 can be greatly improved, and the cost of the torque sensor is greatly reduced. it can.

  Next, a second embodiment will be described with reference to FIG. The arrangement of the sensor module seat surfaces 303 and 316 formed in the shaft body and the depth of the groove 302 must be appropriate for the range of torque to be measured and the maximum allowable characteristics of the detection plate and sensor chip. . Therefore, if a small displacement of the seating surface occurs sufficiently according to the material of the shaft body, heat treatment, diameter, maximum applied torque, etc., the groove is abolished like the shaft body 401, or conversely the minute displacement is insufficient. May be configured to amplify a minute displacement by providing an enlarged outer diameter portion such as 404 only in the torque detected portion. Further, the outer diameter enlarged portion may be formed integrally with the shaft body, or may be configured to mechanically connect the portions 404.

  Next, a third embodiment will be described with reference to FIG. This is an example of a method for manufacturing the sensor module 305 and a method for joining the shaft body. After the sensor module 305 is manufactured in a process similar to semiconductor manufacturing, the sensor module 305 can be circulated as a single unit. The shaft body 301 before fixing the sensor module 305 is generally used to manufacture mechanical parts. Manufactured in a process and can be circulated as a single shaft, both of which are combined to form a shaft body with a torque detector. First, the detection plate 307 of the sensor module 305 is a roll-shaped or rod-shaped detection plate primary processed product by processing a so-called roll-shaped material obtained by winding a thin plate into an X shape or other necessary shape by pressing or the like. 501 is created. This is very similar to the process of manufacturing a semiconductor product lead frame. When a film of a magnetostrictive material is required for the detection plate, it is possible to continuously fix the magnetostrictive film by vapor deposition or sputtering at this stage. Next, a sensor chip 306 is fixed to each X-shaped portion of the detection plate, and the sensor module product 502 is completed by separating them. 3 and 5, the sensor chip is exposed for the sake of explanation. However, as shown in FIG. 6B, the sensor chip portion is made of resin mold 604 or the like like a general semiconductor product. It may be covered. In addition, the sensor module product 502 includes a sensor module 305 that finally remains on the shaft and an ear 505 that is a support portion described later, and a cutout is formed between the ear 505 and the sensor module 305. The ear 505 is for facilitating the handling and positioning of the sensor module 305 before being fixed to the shaft, and therefore the presence or absence of this does not affect the sensor module function. Next, a method for fixing the sensor module product 502 to the processed shaft body 301 will be described. First, the sensor module product 502 is placed on the seat surfaces 303 and 316 of the shaft body and adjusted to a predetermined fixed position. At this time, positioning is easy if the width between the ends of the seating surfaces 303 and 316 is matched with the width of the sensor module product. Further, when the sensor module product 502 is placed on the shaft body 301 or when the position is aligned, the ear 505 is used for easy handling. Next, after positioning the sensor module product 502 on the seating surfaces 303 and 316 of the shaft body 301, the detection plate 502 is fixed by a welding beam 504 using, for example, a laser or an electron. Since the ear 505 is unnecessary if the detection plate 502 is fixed, the ear 505 may be separated by pulling outward.

  According to the above method, the sensor module 305 can be manufactured in the same process as the semiconductor product, and the conventional processing and fixing techniques can be used for mounting the sensor module 305 to the shaft body 301.

  Next, an embodiment of the sensor module inspection apparatus will be described with reference to FIGS. In Patent Document 5, after fixing the sensor module to the shaft body, a known torque is applied to calculate the calibration value by comparing the detected torque information from the sensor with the known torque, and writing this into the sensor module. A method for improving the torque detection accuracy as a torque sensor has been proposed. In this embodiment, since the sensor module 305 before being attached to the shaft body 301 is manufactured and distributed independently, it is necessary to guarantee the function of the sensor module 305. As an inspection means for this purpose, FIG. ), A minute angle generator 701 that generates a minute angle and applies an angular displacement to the sensor module product 502, a minute angle meter 702 that measures the generated minute angle, and an angular displacement generated by the minute angle generator 701. A movable side chuck 703 for transmitting to the sensor module product 502, a fixed side chuck 704 for fixing the opposite side of the sensor module product 502, an electromagnetic wave for power supply to the sensor module, and a signal due to torsional stress detected by the sensor module are received as an electromagnetic wave. The detected angle values of the antenna 705 and the minute angle meter 702 are set to predetermined values. Instructs angle occurs small angle generator 701, consisting of module inspection apparatus 706 for comparing the characteristics and specifications 707 of FIG. 7 obtained in accordance with the small angle change (B).

  When the sensor module product 502 is twisted by a minute angle, a crossing stress in the same direction as that when the sensor module product 502 is fixed to the shaft is applied to the central X-shaped portion. Since this stress depends on the applied angle, a pass / fail judgment is made by comparing the relationship between the angle obtained in advance and the signal from the sensor module.

  According to this inspection method, it is possible to check the function of a single unit even before the sensor module product 502 is mounted on the shaft, and to manage the variation within a range that can be calibrated after the sensor module is mounted on the shaft body. Since the accuracy can be classified, the cost of the sensor module can be reduced.

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 figure which shows the torque detection apparatus of the 1st Embodiment of this invention. The figure which shows the structure of the torque detection apparatus of the 2nd Embodiment of this invention. The figure which shows the structure of the torque detection apparatus of the 3rd Embodiment of this invention. The figure which shows the structure of the signal processing chip | tip of the sensor module shown in FIG. The figure which shows the structure of the inspection apparatus of a sensor module. The figure which shows the conventional torque detection apparatus. The figure which shows the conventional torque detection apparatus improved.

Explanation of symbols

  101, 102 ... Stress generated on the surface of the shaft body, 103 ... Magnetostrictive material, 304, 506 ... Shaft body on which the sensor module is fixed, 305 ... Sensor module to be detected side, 303, 316 ... Seat surface, 306 ... Sensor chip, 307, 602, 603 ... detection plate, 315 ... fixed side module, 501 ... primary processed product of detection plate before separation, 502 ... sensor module product with ear, 504 ... welding beam, 505 ... ear, 601,903 ... magnetostriction Material film, 604 ... resin mold, 701 ... minute angle generator, 702 ... minute angle meter, 703 ... movable side chuck, 704 ... fixed side chuck, 705 ... antenna, 706 ... module inspection device, 707 ... standard value.

Claims (11)

  A shaft body that transmits torque, and a small displacement that is fixed to the shaft body and that can rotate with the shaft body and that is generated by twisting of the shaft body is received as the stress of the module support member, and the torque value is detected and calculated from this stress And a torque detecting device comprising a torque detected module for transmitting the torque information to the outside of the shaft by electromagnetic waves, and using the material characteristics of the module support member or the characteristics of the material fixed on the surface of the support member as a film. .   2. The torque detection device according to claim 1, wherein a part of the shape of the torque detected body module support member is X-shaped, and the torque detection means is disposed at the center.   The torque detection means includes a magnetostrictive material fixed on a main support member of the torque detected module, and a detection coil that is disposed near the surface of the magnetostrictive material and detects an inverse magnetostrictive effect of the magnetostrictive material as an impedance change. The torque detection device according to claim 1, wherein:   2. The torque detection according to claim 1, wherein a semiconductor chip is used for a torque detection portion of the torque detection target module, and a planar or three-dimensional coil for impedance detection is disposed on at least one surface of the semiconductor chip. apparatus.   2. The apparatus according to claim 1, further comprising a means for amplifying a minute displacement due to torsion by providing a groove or an outer diameter enlarged portion for a torque detected body side module portion on a circumference of the shaft body from which the torque is detected. Torque detection device.   The torque detection device according to claim 1, wherein a magnetostrictive material is used for a main support member of the torque detected body module.   2. The torque detecting device according to claim 1, wherein a magnetostrictive material is fixed in a film shape on a part or the entire surface of a main support member of the torque detected body module.   The torque detection device according to claim 1, wherein the torque detection device is formed in a band shape so as to be applied to creation of a plurality of detection target modules as a support member of the torque detection target module.   The torque detection device according to claim 1, wherein the torque detected body module support portion and the shaft body are joined by welding, plastic deformation, insert molding, fusion, or adhesion. .   The torque detection device according to claim 1, wherein a portion different from the support portion is provided in a main support portion of the torque detected body module, and the portion is separated after the coupling with the shaft body is completed.   The operation of the module itself is confirmed by applying a torsional stress to the main support part of the torque detected module from outside while holding both ends of the torque detected module alone and electrically operating the module. The torque detection device according to claim 1.

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