JP2020012783A - Distortion sensor structure and distortion detection method - Google Patents

Abstract

To provide a distortion sensor structure and a distortion detection method having high detection accuracy with a simple configuration.SOLUTION: A first magnetostrictive member 30 is provided on the rotating shaft 20. A first permanent magnet 70 and a second permanent magnet 71 have an annular shape and are installed at an interval in the axial direction A of a rotating shaft 20 so as to be opposite to each other coaxially with the rotating shaft 20. The first permanent magnet 70 and the second permanent magnet 71 are opposite to the first magnetostrictive member 30. In the downward of the first permanent magnet 70, two first Hall elements 80 indicated by a support member (not shown) are provided. The first Hall element 80 is provided in the vicinity of the first magnetostrictive member so that the magnetic flux density between the first permanent magnet 70 and the second permanent magnet 71 can be detected.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a strain sensor structure and a strain detection method, and more particularly, to a strain sensor structure and a strain detection method for detecting a rotation axis distortion from a change in magnetic flux.

  As a structure of a conventional strain sensor mounted on a device such as a steering device of a vehicle, for example, a strain sensor described in Patent Literature 1 below is known. That is, in the conventional strain sensor 1 shown in FIG. 4, the first magnetostrictive material portion 30 and the second magnetostrictive material portion 31 which are anisotropy imparting members are provided on the outer peripheral surface of the rotating shaft 2 in a ring shape. A first annular detection coil 41 and a second annular detection coil 42 are provided so as to face each other in the axial direction of the rotating shaft 2 so as to face the material portion 30, and face the second magnetostrictive material portion 31. The third annular detection coil 43 and the fourth annular detection coil 44 are provided so as to be displaced from each other in the axial direction of the rotating shaft 2. The second magnetostrictive member 31 is provided so as to have a phase difference of 90 degrees with respect to the magnetic anisotropy of the first magnetostrictive member 30.

  When torque is applied to the rotating shaft 2, distortion occurs in the rotating shaft 2, causing distortion in the first magnetostrictive member 30 and the second magnetostrictive member 31, and causes the first magnetostriction due to the Villari effect. The magnetic domain of the material portion 30 and the second magnetostrictive material portion 31 is rotated and aligned to change the magnetic permeability, thereby changing the magnetic flux. Then, the impedances of the first and second annular detection coils 41 and 42 and the third and fourth annular detection coils 43 and 44 change. The detection voltages of the first, second, third, and fourth annular detection coils 41, 42, 43, and 44 change. Therefore, by measuring the detection voltage of the first, second, third, and fourth annular detection coils 41, 42, 43, and 44, the magnetic permeability of the first magnetostrictive member 30 and the second magnetostrictive member 31 is measured. , The distortion of the rotating shaft 2 can be detected. Then, the torque applied to the rotating shaft 2 can be calculated from the distortion of the rotating shaft 2.

JP 2006-64445 A

  In the conventional strain sensor 1 as described above, the generation of the magnetic flux passing through the first and second magnetostrictive members 30 and 31 and the detection of the magnetic flux of the first and second magnetostrictive members 30 and 31 are performed by the second sensor. This is performed by the first, second, third, and fourth annular detection coils 41, 42, 43, and 44. Therefore, since the uniformity of the windings of the first, second, third, and fourth annular detection coils 41, 42, 43, and 44 affects the detection accuracy of the magnetic flux, it is necessary to secure the detection accuracy of the strain sensor. There has been a problem that the uniformity of the winding required for the coil is increased and production becomes difficult.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a strain sensor structure and a strain detection method with a simple configuration and high detection accuracy.

  In order to solve the above-described problem, a strain sensor structure according to the present invention includes a rotation sensor provided with a first magnetostrictive material portion, which is an anisotropy imparting member, so that a magnetostriction characteristic is reversed by reversing a rotation direction. A shaft, a magnet provided radially outside the rotation shaft, a yoke supporting the magnet, and a magnetic sensor provided to detect a magnetic flux generated by the magnet, wherein the magnetic sensor is It is configured to detect a change in magnetic flux generated by the first magnetostrictive member when a torque is applied to a rotation axis, and the magnet is a ring-shaped magnet provided coaxially with the rotation axis, And a plurality of magnets are provided in the circumferential direction of the rotating shaft, and the number of the magnets varies along the radial direction of the rotating shaft. And the rotation shaft A second magnetostrictive member, which is an anisotropy imparting member, is further provided so that the magnetostriction characteristics are inverted by reversing the rotation direction, and the magnetic sensor is configured such that when torque is applied to the rotating shaft, The magnetic sensor is configured to detect a change in magnetic flux generated by the second magnetostrictive member, and the magnetic sensor is a Hall element.

  Further, in order to solve the above problem, a distortion detection method according to the present invention provides a rotating shaft provided with a magnetostrictive material portion which is an anisotropy imparting member so that a magnetostriction characteristic is reversed by reversing a rotation direction. And a magnet provided radially outside the rotation shaft, a yoke supporting the magnet, and a magnetic sensor provided to detect a magnetic flux generated by the magnet, wherein the magnetic sensor is And detecting a change in magnetic flux generated by the magnetostrictive member when torque is applied to the rotating shaft.

  According to the strain sensor structure of the present invention, the magnet includes: a magnet provided radially outside the rotation shaft having the first magnetostrictive member; and a magnetic sensor provided so as to detect a magnetic flux generated by the magnet. Since the sensor is configured to detect a change in magnetic flux generated by the first magnetostrictive member when a torque is applied to the rotating shaft, a strain sensor structure having a simple configuration and high detection accuracy can be provided.

FIG. 2 is a schematic sectional view of the strain sensor according to Embodiment 1 of the present invention. FIG. 7 is a schematic sectional view of a strain sensor according to Embodiment 2 of the present invention. FIG. 10 is a schematic plan view of a strain sensor according to Embodiment 3 of the present invention. It is the schematic of the conventional distortion sensor.

Embodiment 1 FIG.
Hereinafter, a strain sensor according to Embodiment 1 of the present invention will be described with reference to the accompanying drawings. The same or equivalent parts as those in the conventional example will be described with the same reference numerals.
FIG. 1 shows a schematic sectional view of the strain sensor 10. A ring-shaped first yoke 50 made of a magnetic material is provided outside the rotation shaft 20 of the strain sensor 10. The first yoke 50 constitutes a yoke. A housing 60 is provided outside the first yoke 50 in the radial direction. In the drawings after FIG. 1, description of some components such as a bearing and a wiring of the strain sensor is omitted.

  On the rotating shaft 20, a first magnetostrictive material portion 30, which is an alloy film formed by plating on a radially outer peripheral surface, is arranged in series in the longitudinal direction of the rotating shaft 20, that is, along the axial direction A of the rotating shaft 20. It is formed.

  The first magnetostrictive member 30 is formed by performing a plating process so that the magnetostriction characteristics are reversed between a case where a clockwise torque is applied to the rotating shaft 20 and a case where a counterclockwise torque is applied to the rotating shaft 20. I have. That is, the first magnetostrictive member 30 constitutes an anisotropy imparting member.

  A first permanent magnet 70 and a second permanent magnet 71 are installed on an upper inner side and an inner lower side of the first yoke 50. The first permanent magnet 70 and the second permanent magnet 71 have a ring shape, and are arranged at intervals in the axial direction A of the rotating shaft 20 so as to be coaxial with and opposed to the rotating shaft 20. . That is, the first permanent magnet 70 and the second permanent magnet 71 face the first magnetostrictive member 30. The first permanent magnet 70 and the second permanent magnet 71 constitute a magnet.

  The first permanent magnet 70 and the second permanent magnet 71 are arranged so that the upper side along the axial direction A is the south poles 70s and 71s, and the lower side is the north poles 70n and 71n. Therefore, the N pole 70n of the first permanent magnet 70 and the S pole 71s of the second permanent magnet 71 face each other. That is, the first permanent magnet 70 and the second permanent magnet 71 are configured such that poles facing each other along the axial direction of the rotating shaft 20 are different.

  Below the first permanent magnet 70, two first Hall elements 80 indicated by a support member (not shown) are provided. The first Hall element 80 is provided near the first magnetostrictive member so as to detect a magnetic flux generated by the first permanent magnet 70 and the second permanent magnet 71, and is connected to a detection circuit (not shown). ing. The first Hall element 80 constitutes a magnetic sensor.

Next, the operation of the strain sensor 10 according to the first embodiment will be described.
First, when no torque is applied to the rotating shaft 20, the N pole 70n of the first permanent magnet 70 and the S pole 71s of the second permanent magnet 71 face each other. The magnetic flux B between the N pole 70n of the permanent magnet 70 and the S pole 71s of the second permanent magnet 71 passes through the first magnetostrictive member 30. The magnetic flux B passing through the first magnetostrictive member 30 at this time is detected by the first Hall element 80.

  Next, when a torque is applied to the rotating shaft 20, the first magnetostrictive member 30 is distorted according to the direction of the torque applied to the rotating shaft 20, and the magnetic permeability changes due to the Villari effect. Due to this change, the magnetic flux density of the first magnetostrictive member 30 changes, so that the magnetic flux B transmitted through the first magnetostrictive member changes, and is detected by the first Hall element 80. The change in the magnetic flux B of the first magnetostrictive material portion 30 between the case where the torque is not applied to the rotation shaft 20 and the case where the torque is applied is detected by the first Hall element 80, and Can be detected.

  When the first, second, third, and fourth annular detection coils 41, 42, 43, and 44 are used to detect a change in magnetic flux as in the strain sensor 1 of Patent Document 1, each detection coil The uniformity of the winding affects the detection accuracy. On the other hand, when the change of the magnetic flux B is detected by the first Hall element 80 as in the first embodiment, it is not necessary to manufacture a coil having a high uniformity of the winding. Simplicity and therefore production.

  Further, in the strain sensor 1 of Patent Document 1, an AC magnetic field is applied by a coil to detect a strain, and the impedance of the first, second, third, and fourth ring-shaped detection coils 41, 42, 43, and 44 is determined. A change in magnetic flux is detected. However, in this method, an eddy current loss or a hysteresis loss occurs due to the AC magnetic field, and the efficiency with respect to the input power to the strain sensor 1 decreases. On the other hand, when a DC magnetic field is applied by the first permanent magnet 70 and the second permanent magnet 71 and the magnetic flux B is transmitted through the first magnetostrictive member 30 as in the first embodiment, an AC magnetic field is applied. Thus, the eddy current loss and the hysteresis loss can be suppressed more than in the case of performing the above operation, and the decrease in efficiency with respect to the input power to the strain sensor 10 can be suppressed.

  Further, as compared with the method of applying a magnetic field by a coil as in the strain sensor 1 of Patent Document 1, the magnetic field is applied by the first permanent magnet 70 and the second permanent magnet 71 as in the first embodiment. Since the method can generate the magnetic flux B more uniformly than the coil, the detection accuracy of the magnetic flux of the strain sensor 10 is improved.

  Further, when the first, second, third, and fourth ring-shaped detection coils 41, 42, 43, and 44 are provided as in the distortion sensor 1 of Patent Document 1, winding is performed particularly in a redundant system configuration. In order to secure the location of the line, the strain sensor 1 is limited in size and layout freedom. On the other hand, the method of applying a magnetic field by the first permanent magnet 70 and the second permanent magnet 71 as in the first embodiment does not require a winding, so that space can be saved, and the system is compatible with a redundant system. It's easy to do.

  As described above, the rotation shaft 20 provided with the first magnetostrictive member 30 serving as the anisotropy providing member and the radial direction of the rotation shaft 20 so that the magnetostriction characteristics are reversed by reversing the rotation direction. The first and second permanent magnets 70 and 71 provided outside the first and second permanent magnets 70 and 71, the first yoke 50 supporting the first and second permanent magnets 70 and 71, the first and second permanent magnets 70 and 71, The first Hall element 80 provided so as to be able to detect the magnetic flux B generated by the first 71. The first Hall element 80 is provided by the first magnetostrictive member 30 when a torque is applied to the rotating shaft 20. Since the change in the generated magnetic flux B is detected, a strain sensor structure with high detection accuracy can be obtained with a simple structure.

  The first and second permanent magnets 70 and 71 are ring-shaped magnets provided coaxially with the rotating shaft 20, and are arranged in a plurality in the axial direction A, and poles are formed along the axial direction A of the rotating shaft 20. Therefore, the uniformity of the generated magnetic flux B and the detection accuracy of the magnetic flux B can be improved with a simple configuration.

  Further, since the first Hall element 80 is provided as a magnetic sensor, it is not necessary to manufacture a coil having a higher uniformity of winding than when the magnetic sensor is a detection coil. The configuration is simplified. Further, a decrease in efficiency with respect to the input power to the strain sensor 10 is suppressed, and the accuracy of detecting the magnetic flux B of the strain sensor 10 is improved. Furthermore, space saving for the strain sensor 10 is possible, and it is easy to cope with a redundant system.

  Further, the rotation shaft 20 provided with the first magnetostrictive material portion 30 as an anisotropy imparting member and a radially outer portion of the rotation shaft 20 so that the magnetostriction characteristics are reversed by reversing the rotation direction. , The first and second permanent magnets 70 and 71, the first yoke 50 that supports the first and second permanent magnets 70 and 71, and the first and second permanent magnets 70 and 71. In the strain sensor 10 including the first magnetic sensor 80 provided so as to be able to detect the generated magnetic flux B, the first magnetic sensor 80 is configured to be capable of receiving the first magnetostrictive material when a torque is applied to the rotating shaft 20. Since this is a method for detecting a change in the magnetic flux B generated by the unit 30, a distortion detection method with a simple configuration and high detection accuracy can be provided.

Embodiment 2 FIG.
Next, a strain sensor 11 according to a second embodiment of the present invention will be described. In the following embodiments, the same reference numerals as those in FIG. 1 denote the same or similar components, and a detailed description thereof will be omitted.
The second embodiment is a strain sensor in which a second magnetostrictive member is further provided in the first embodiment.
FIG. 2 shows a schematic sectional view of the strain sensor 11. The rotating shaft 21 is provided with the first magnetostrictive member 30 and a second magnetostrictive member 31 which is an alloy film. The second magnetostrictive member 31 is formed in a radially outer peripheral surface by plating so as to be adjacent to the first magnetostrictive member 30 in series in the longitudinal direction of the rotating shaft 21, that is, the axis of the rotating shaft 21. It is formed along the direction A.

  The second magnetostrictive material portion 31 is formed by performing a plating process so that the magnetostriction characteristics are reversed when the clockwise torque is applied to the rotating shaft 21 and when the counterclockwise torque is applied to the rotating shaft 21. I have. That is, the second magnetostrictive member 31 constitutes an anisotropy imparting member. Further, the second magnetostrictive member 31 has opposite magnetostrictive characteristics when a clockwise torque is applied to the rotating shaft 21 and a counterclockwise torque is applied to the first magnetostrictive member 30. The plating process is performed as follows.

  The strain sensor 11 further includes a second yoke 51 formed of a magnetic material inside the housing 60. The second yoke 51 forms a yoke. A third permanent magnet 71 and a fourth permanent magnet 72 are installed on the upper and lower inner sides of the second yoke 51. The configuration of the second yoke 51 is the same as that of the first yoke 50, and the configuration of the third permanent magnet 71 and the fourth permanent magnet 72 is the same as that of the first permanent magnet 70 and the second permanent magnet 71. It has the same configuration. The third permanent magnet 71 and the fourth permanent magnet 72 constitute a magnet.

  Below the third permanent magnet 72, two second Hall elements 81 indicated by support members (not shown) are provided. The second Hall element 81 is provided near the second magnetostrictive member so as to detect a magnetic flux C generated by the third permanent magnet 72 and the fourth permanent magnet 73, and is connected to a detection circuit (not shown). Have been. The second Hall element 81 forms a magnetic sensor.

Next, the operation of the strain sensor 11 according to the second embodiment will be described.
First, when no torque is applied to the rotating shaft 21, the N pole 70 n of the first permanent magnet 70 and the S pole 71 s of the second permanent magnet 71 face each other. The magnetic flux B between the N pole 70n of the permanent magnet 70 and the S pole 71s of the second permanent magnet 71 passes through the first magnetostrictive member 30. At this time, the magnetic flux B of the first magnetostrictive member 30 is detected by the first Hall element 80.

  When no torque is applied to the rotating shaft 21, the N pole 72 n of the third permanent magnet 72 and the S pole 73 s of the fourth permanent magnet 73 face each other. The magnetic flux C between the N pole 72n of the permanent magnet 72 and the S pole 73s of the fourth permanent magnet 73 passes through the second magnetostrictive member 31. At this time, the magnetic flux C of the second magnetostrictive member 31 is detected by the second Hall element 81. Then, a difference between the detection result of the first Hall element 80 and the detection result of the second Hall element 81 is calculated by a detection circuit (not shown).

  Next, when torque is applied to the rotating shaft 21, the first magnetostrictive member 30 and the second magnetostrictive member 31 are distorted according to the direction in which the torque is applied to the rotating shaft 21, and the transmission is performed. Magnetic susceptibility changes due to the Villari effect. Due to this change, the magnetic flux density of the first magnetostrictive member 30 and the second magnetostrictive member 31 changes, so that the magnetic flux B transmitted through the first magnetostrictive member 30 and the magnetic flux transmitted through the second magnetostrictive member 31 C changes and is detected by the first Hall element 80 and the second Hall element 81. Then, a difference between the detection result of the first Hall element 80 and the detection result of the second Hall element 81 is calculated by a detection circuit (not shown).

  Next, the difference between the detection result of the magnetic flux when the torque is not applied to the rotating shaft 21 and the difference between the detection results of the magnetic flux when the torque is applied to the rotating shaft 21 is changed. The distortion of the shaft 21 can be detected.

  Since the first magnetostrictive member 30 and the second magnetostrictive member 31 have anisotropy opposite to each other, the value of the change in magnetic flux when torque is applied to the rotating shaft 21 is opposite. Therefore, the difference between the detection result of the first Hall element 80 and the detection result of the second Hall element 81 is calculated and used as the detection result, so that only the detection result of the first Hall element 80 is used. The strain sensor 11 of the second embodiment has a larger strain detection value than the strain sensor 10 of the first embodiment, and the measurement accuracy of the strain is improved.

  As described above, the second magnetostrictive member 31 serving as an anisotropy imparting member is further provided on the rotation shaft 21 so that the magnetostriction characteristics are inverted by reversing the rotation direction, and the magnetic sensors 80 and 81 are provided. Detects the change in the magnetic flux generated by the second magnetostrictive member 31 when a torque is applied to the rotating shaft 21, so that the accuracy of the strain sensor can be improved.

Embodiment 3 FIG.
Next, a strain sensor according to Embodiment 3 of the present invention will be described.
The third embodiment is different from the first embodiment in the arrangement of the permanent magnet.
FIG. 3 is a schematic plan view of the strain sensor 12. As shown in FIG. 3, which is a plan view seen from the axial direction of the rotary shaft 20, the strain sensor 12 has a fifth permanent magnet 74 and a sixth permanent magnet attached to an annular third yoke 52 made of a magnetic material. The magnet 75, the seventh permanent magnet 76, and the eighth permanent magnet 77 are attached. The third yoke 52 constitutes a yoke. The fifth permanent magnet 74, the sixth permanent magnet 75, the seventh permanent magnet 76, and the eighth permanent magnet 77 constitute a magnet. The fifth permanent magnet 74, the sixth permanent magnet 75, the seventh permanent magnet 76, and the eighth permanent magnet 77 are arranged at equal intervals in the circumferential direction of the rotating shaft 20.

  The fifth permanent magnet 74 and the seventh permanent magnet 76 are arranged such that the outer side in the radial direction of the rotating shaft 20 is N poles 74n and 76n, and the inner side is S poles 74s and 76s. On the other hand, the sixth permanent magnet 75 and the eighth permanent magnet 77 are arranged such that the outer sides in the radial direction of the rotating shaft 20 are S poles 75s and 77s, and the inner sides are N poles 75n and 77n. That is, the poles of the fifth permanent magnet 74, the sixth permanent magnet 75, the seventh permanent magnet 76, and the eighth permanent magnet 77 change along the radial direction of the rotating shaft 20.

  The first Hall element 80 indicated by a support member (not shown) is provided radially inward of the fifth permanent magnet 74, the sixth permanent magnet 75, the seventh permanent magnet 76, and the eighth permanent magnet 77, respectively. Have been. The first Hall element 80 is provided near the second magnetostrictive member so as to detect the magnetic flux of the fifth, sixth, seventh, and eighth permanent magnets 74, 75, 76, 77. Not connected to the detection circuit. The first Hall element 80 constitutes a magnetic sensor.

Next, the operation of the strain sensor 12 according to the third embodiment will be described.
First, when no torque is applied to the rotating shaft 20, the fifth permanent magnet 74 and the seventh permanent magnet 76 have N poles 74n and 76n on the outside in the radial direction of the rotating shaft 20, and S on the inside inside. The sixth permanent magnet 75 and the eighth permanent magnet 77 are arranged so as to be the poles 74 s and 76 s. On the other hand, the sixth permanent magnet 75 and the eighth permanent magnet 77 are S poles 75 s and 77 s on the outside in the radial direction of the rotating shaft 20 and N poles 75 n and 77 n on the inside. Thus, the magnetic flux D passes through the first magnetostrictive member 30.

  Next, when a torque is applied to the rotating shaft 20, the first magnetostrictive member 30 is distorted according to the direction of the torque applied to the rotating shaft 20, and the magnetic permeability changes due to the Villari effect. Due to this change, the magnetic flux density in the circumferential direction between each of the fifth permanent magnet 74, the sixth permanent magnet 75, the seventh permanent magnet 76, and the eighth permanent magnet 77 changes, so that the first magnetostriction The magnetic flux D passing through the material part 30 changes.

  As in the operation of the strain sensor 10 of the first embodiment, the first Hall element 80 detects a change in magnetic flux when the torque is not applied to the rotating shaft 20 and when the torque is applied. This makes it possible to detect distortion of the rotating shaft 20 due to a torque applied to the rotating shaft 20 due to a change in magnetic flux.

  As described above, the plurality of fifth, sixth, seventh, and eighth permanent magnets 74, 75, 76, and 77 are provided in the circumferential direction of the rotating shaft 20, and the poles change along the radial direction of the rotating shaft 20. Accordingly, the overall length of the strain sensor 12 in the axial direction A is reduced, and the strain sensor 12 can be made compact.

  In the first embodiment of the present invention, the two first Hall elements 80 are provided. In the second embodiment, the first Hall element 80 and the second Hall element 81 are provided two by two. Although four 1-Hall elements 80 are provided near the first to eighth permanent magnets 70 to 77, the positions and numbers of the first and second Hall elements 80 and 81 are as follows. What is necessary is just to provide in the arbitrary position which can detect the change of the magnetic flux by the distortion of the magnetostrictive material part 30 and the said 2nd magnetostrictive material part 31.

  In the first to third embodiments of the present invention, the first Hall element 80 and the second Hall element 81 are provided as magnetic sensors. However, a magnetic sensor of a type other than the Hall element may be used. Good.

  In the first to third embodiments of the present invention, the first magnetostrictive member 30 and the second magnetostrictive member 31 are subjected to a plating process so that clockwise torque is applied to the rotating shafts 20 and 21; The magnetic anisotropy is formed by inverting the magnetostriction characteristics when the counterclockwise torque is applied, but the magnetic anisotropy may be provided by another method. For example, the first magnetostrictive material portion 30 and the second magnetostrictive material portion 31 are subjected to groove processing, and the surfaces of the first magnetostrictive material portion 30 and the second magnetostrictive material portion 31 are processed by thermal spraying. The first magnetostrictive member 30 and the second magnetostrictive member 31 may have magnetic anisotropy. Further, not only the surfaces of the rotating shafts 20 and 21 but also a part or the whole of the rotating shafts 20 and 21 may be formed of a magnetostrictive material portion.

  In the first to third embodiments of the present invention, the first to third yokes 50 to 52 are provided. However, the first to third yokes 50 to 52 may have any shape. Alternatively, a stay made of a non-magnetic material that supports the first to eighth permanent magnets 70 to 77 may be used instead of the first to third yokes 50 to 52.

  Further, the first and second annular permanent magnets 70 and 71 are provided in the first embodiment of the present invention, and the first to fourth permanent magnets 70 to 73 are provided in the second embodiment. The first to fourth permanent magnets 70 to 73 may not be completely annular permanent magnets as long as the poles facing each other along the axial direction of the rotating shafts 20 and 21 are different. For example, a plurality of magnets may be arranged side by side in the circumferential direction of the rotation shafts 20 and 21.

  Further, in the second embodiment, two types of the first and second magnetostrictive material portions 30 and 31 and the ring-shaped first and second magnetostrictive material portions 30 and 31 are opposed to each other. Although the second permanent magnets 70 and 71 and the third and fourth permanent magnets 72 and 73 are provided respectively, three or more magnetostrictive members may be provided on the rotating shaft 21 or the magnetostrictive member may be provided on the rotating shaft 21. The number of opposing permanent magnets may be any number.

  In the second embodiment, the first to fourth permanent magnets 70 to 73 are ring-shaped magnets provided coaxially with the rotating shaft 21, and change their poles along the axial direction A of the rotating shaft 21. However, the permanent magnets are arranged in the circumferential direction of the rotating shaft 21 like the fifth to eighth permanent magnets 74 to 77 of the third embodiment, and the poles are arranged along the radial direction of the rotating shaft 21. You may provide so that it may change.

  Further, in the third embodiment, four permanent magnets of the fifth to eighth permanent magnets 74 to 77 are provided, but the position and number of the permanent magnets are permanent when viewed from the axial direction of the rotary shaft 20. Arbitrary positions and numbers may be used as long as the magnets are arranged so as to be targeted.

  The gist of the strain sensor structure and the strain detection method according to the present invention is as follows. That is, the rotating shaft 20 having the first magnetostrictive member 30 serving as an anisotropic member provided on the surface thereof, and the radial direction of the rotating shaft 20 so that the magnetostriction characteristics are reversed by reversing the rotating direction. The first and second permanent magnets 70 and 71 provided on the outside, the first yoke 50 that supports the first and second permanent magnets 70 and 71, and the first and second permanent magnets 70 and 71 A first magnetic sensor 80 provided so as to be able to detect the generated magnetic flux B. The first magnetic sensor 80 is provided by the first magnetostrictive member 30 when a torque is applied to the rotating shaft 20. The first and second magnets 70 and 71 are annular magnets provided coaxially with the rotating shaft 20, and are arranged in a plurality in the axial direction A. The configuration in which the pole changes along the axial direction A of 20 Further, a plurality of the fifth to eighth permanent magnets 74 to 77 are provided in the circumferential direction of the rotating shaft 20, and the poles change along the radial direction of the rotating shaft 20. The second magnetostrictive member 31 which is an anisotropy imparting member is further provided on the surface of the shaft 21 so that the magnetostriction characteristics are reversed by reversing the rotation direction. Reference numeral 81 denotes a configuration for detecting a change in the magnetic flux C generated by the second magnetostrictive member 31 when a torque is applied to the rotating shaft 21, and the first and second magnetic sensors 80, 81 The rotation shaft 20 provided with the first magnetostrictive member 30 as an anisotropy imparting member on its surface so that the magnetostriction characteristics are reversed by reversing the rotation direction. Provided radially outside of the rotating shaft 20. First and second magnets 70 and 71, first yoke 50 supporting first and second magnets 70 and 71, and magnetic flux B generated by first and second magnets 70 and 71 are provided to be detectable. The first magnetic sensor 80, the first magnetic sensor 80 detects a change in the magnetic flux B generated by the first magnetostrictive member 30 when a torque is applied to the rotating shaft 20. This is a detection method for detection.

  The strain sensor structure according to the present invention includes: a rotating shaft having a first magnetostrictive member serving as an anisotropic member provided on a surface thereof; and a radial direction of the rotating shaft, the magnetostriction characteristics being reversed by reversing the rotating direction. A magnet provided outside of the magnet, a yoke supporting the magnet, and a magnetic sensor provided to detect a magnetic flux generated by the magnet, wherein the magnetic sensor has a first magnetostriction when torque is applied to a rotating shaft. Since it is configured to detect a change in magnetic flux generated by the material portion, it is possible to obtain a strain sensor structure with high detection accuracy with a simple configuration.

10, 11, 12 Strain sensor 20, 21 Rotation axis 30 First magnetostrictive material section 31 Second magnetostrictive material section 50 First yoke (yoke)
51 2nd yoke (yoke)
52 Third yoke (yoke)
70 1st permanent magnet (magnet)
71 Second permanent magnet (magnet)
72 Third permanent magnet (magnet)
73 4th permanent magnet (magnet)
74 5th permanent magnet (magnet)
75 6th permanent magnet (magnet)
76 7th permanent magnet (magnet)
77 8th permanent magnet (magnet)
80 First Hall Element (First Magnetic Sensor)
81 Second Hall Element (Second Magnetic Sensor)
A-axis direction B, C, D Magnetic flux

Claims (6)

A rotating shaft (20, 21) provided with a first magnetostrictive member (30), which is an anisotropy imparting member, so that the magnetostriction characteristics are reversed by reversing the rotation direction;
Magnets (70, 71, 72, 73, 74, 75, 76, 77) provided radially outside the rotation shafts (20, 21);
A yoke (50, 51, 52) for supporting the magnet (70, 71, 72, 73, 74, 75, 76, 77);
Magnetic sensors (80, 81) provided so as to detect magnetic fluxes (B, C, D) generated by the magnets (70, 71, 72, 73, 74, 75, 76, 77),
The magnetic sensors (80, 81) detect changes in the magnetic fluxes (B, C, D) generated by the first magnetostrictive member (30) when a torque is applied to the rotating shafts (20, 21). A strain sensor structure.   The magnets (70, 71, 72, 73) are ring-shaped magnets provided coaxially with the rotation shafts (20, 21), and are arranged in a plurality in the axial direction (A). The strain sensor structure according to claim 1, wherein the pole changes along the axial direction (A).   The said magnet (74,75,76,77) is provided with two or more by the circumferential direction of the said rotating shaft (20), The pole changes along the radial direction of the said rotating shaft (20), The Claims characterized by the above-mentioned. 4. The strain sensor structure according to 1. A second magnetostrictive material portion (31), which is an anisotropy imparting member, is further provided on the rotation shaft (20, 21) so that the magnetostriction characteristics are inverted by reversing the rotation direction,
The magnetic sensor (80, 81) detects a change in the magnetic flux (C) generated by the second magnetostrictive member (31) when a torque is applied to the rotating shaft (20, 21). The strain sensor structure according to claim 1, wherein   The strain sensor structure according to any one of claims 1 to 4, wherein the magnetic sensor (80, 81) is a Hall element. A rotating shaft (20) provided with a first magnetostrictive member (30), which is an anisotropy imparting member, so that the magnetostriction characteristics are reversed by reversing the rotation direction;
Magnets (70, 71) provided radially outside the rotating shaft (20);
A yoke (50) for supporting the magnets (70, 71);
A magnetic sensor (80) provided to detect a magnetic flux (B) generated by the magnets (70, 71);
A distortion detecting method, wherein the magnetic sensor detects a change in the magnetic flux (B) generated by the first magnetostrictive member (30) when a torque is applied to the rotating shaft (20).

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