JP2020041803A - Strain sensor structure - Google Patents

Abstract

To provide a strain sensor capable of preventing an increase in manufacturing cost and man-hour.SOLUTION: A strain sensor 10 includes a rotating shaft 20, a magnetostrictive member 21 provided on the rotating shaft 20, a ring-shaped coil 30 provided on the outer peripheral side of the rotating shaft 20, and a magnetic shield member 50 provided between the magnetostrictive member 21 and the ring-shaped coil 30 to block magnetic flux. The ring-shaped coil 30 includes a ring-shaped detection coil 32, and is provided such that a center axis A of the ring-shaped coil 30 is oblique to an axial direction B of the rotating shaft 20. The magnetic shield member 50 is provided on a part of the rotating shaft 20 in the circumferential direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a strain sensor structure, and more particularly, to a strain sensor structure for detecting a rotation axis distortion from a change in coil impedance.

  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 2a and the second magnetostrictive material portion 2b, 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 3a and a second annular detection coil 3b are provided so as to be opposed to each other in the axial direction of the rotating shaft 2 so as to face the material portion 2a, and to face the second magnetostrictive material portion 2b. The third annular detection coil 3c and the fourth annular detection coil 3d are provided so as to be displaced from each other in the axial direction of the rotating shaft 2. The second magnetostrictive member 2b is provided so as to have a phase difference of 90 degrees with respect to the magnetic anisotropy of the first magnetostrictive member 2a.

  When a force is applied to the rotating shaft 2, distortion occurs in the rotating shaft 2, causing distortion in the first magnetostrictive material portion 2 a and the second magnetostrictive material portion 2 b, and causing the first magnetostrictive material to vibrate. In the portion 2a and the second magnetostrictive material portion 2b, the magnetic domain is rotated and aligned to change the magnetic permeability, thereby changing the magnetic flux. Then, the impedance of the first and second annular detection coils 3a and 3b and the third and fourth annular detection coils 3c and 3d changes, and the first and second annular detection coils 3c and 3d change in impedance. The detection voltages of the first, second, third, and fourth annular detection coils 3a, 3b, 3c, 3d change. Therefore, by measuring the detection voltages of the first, second, third, and fourth annular detection coils 3a, 3b, 3c, and 3d, the transmission of the first magnetostrictive member 2a and the second magnetostrictive member 2b is measured. By calculating the change in magnetic susceptibility, the distortion of the rotating shaft 2 can be detected.

JP 2006-64445 A

  In the conventional strain sensor 1 as described above, the first magnetostrictive member 2a and the second magnetostrictive member 2b are previously subjected to a heat treatment by, for example, high-frequency heating, or the first magnetostrictive member 2a and the second (2) Groove processing is performed on the surface of the magnetostrictive material portion 2b, and magnetic anisotropy is imparted by changing the groove processing direction of the first magnetostrictive material portion 2a and the second magnetostrictive material portion 2b at that time. . For this reason, there is a problem that the manufacturing cost and the number of manufacturing steps of the strain sensor 1 increase due to the processing.

  The present invention has been made in order to solve such a problem, and it is not necessary to perform a process for giving anisotropy to a magnetostrictive material portion, and it is possible to reduce a manufacturing cost and a manufacturing man-hour. It is intended to provide a sensor.

  In order to solve the above-mentioned problem, a strain sensor structure according to the present invention includes a rotating shaft, a magnetostrictive member provided on the rotating shaft, a ring-shaped coil provided on an outer peripheral side of the rotating shaft, A magnetic shield member provided between the material portion and the ring-shaped coil to block magnetic flux, the ring-shaped coil has a ring-shaped detection coil, and a center axis of the ring-shaped coil is in an axial direction of the rotation axis. The magnetic shield member is provided so as to be oblique to the direction, and the magnetic shield member is provided in a part of a circumferential direction of the rotating shaft.

The ring-shaped coil has a first position closest to one end of the rotating shaft and a second position closest to the other end of the rotating shaft, and the magnetic shield member is configured to rotate the rotating shaft. When viewed from the axial direction of the shaft, the shaft may be provided between a position closest to the first position and a position closest to the second position in a circumferential direction of the rotating shaft.
Further, the ring-shaped coil has a magnetic domain rotation direction or a magnetic domain alignment direction of the magnetostrictive member due to a strain generated in the rotation axis when a force is applied to the rotation axis, and a direction of a detection magnetic flux linked to the ring-shaped detection coil. May be provided so as to coincide or be orthogonal to each other.
Further, the ring-shaped coil, the direction of the magnetic domain rotation of the magnetostrictive member portion due to distortion generated in the rotation axis when a force is applied to the rotation axis, and the direction of the detection magnetic flux linked to the ring-shaped detection coil, They may be provided so as to be coincident or orthogonal.
Further, the ring-shaped coil, the magnetic domain alignment direction of the magnetostrictive member portion due to distortion generated in the rotation axis when applying a force to the rotation axis, and the direction of the detection magnetic flux linked to the ring-shaped detection coil, They may be provided so as to be coincident or orthogonal.
Further, the magnetostrictive member may be made of a material different from the rotating shaft.

  According to the strain sensor structure according to the present invention, the magnetic sensor includes the magnetic shield member that blocks magnetic flux between the magnetostrictive member and the ring-shaped coil, and the magnetic shield member is provided on a part of the rotation shaft in a circumferential direction. Since it is provided, it is not necessary to perform processing for imparting anisotropy to the magnetostrictive member, and it is possible to prevent an increase in the manufacturing cost and man-hour of the strain sensor.

It is a front view of the distortion sensor concerning an embodiment of the invention. It is a left view of the distortion sensor of FIG. It is a top view of the distortion sensor of FIG. It is the schematic of the conventional distortion sensor.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The same or equivalent parts as those in the conventional example will be described with the same reference numerals.
FIG. 1 is a front view of a strain sensor 10 according to an embodiment of the present invention. The distortion sensor 10 is provided with a rotating shaft 20 to which a force is applied from the outside. The rotating shaft 20 is provided with a magnetostrictive member 21. The magnetostrictive member 21 is made of a material different from that of the rotating shaft 20, and is made of a magnetostrictive material whose magnetic permeability changes according to a strain generated when a force is applied to the rotating shaft 20. The material used for the magnetostrictive material portion 21 is desirably a material having a high magnetic permeability. For example, an arbitrary magnetostrictive material such as a Ni—Fe alloy or an Fe—Co alloy is used. Note that the rotation shaft 20 and the magnetostrictive member 21 may be formed of the same material. In addition, in the drawings after FIG. 1, description of some components such as a bearing, a fixing member, and a wiring of the strain sensor is omitted.

  An annular coil 30 which is a bobbin coil is provided on the outer peripheral side of the rotating shaft 20. The ring-shaped coil 30 is formed by winding a ring-shaped excitation coil 31 and a ring-shaped detection coil 32 integrally with an air-core bobbin formed of an insulator such as a resin. The rotating shaft 20 is formed to be rotatable. The ring-shaped excitation coil 31 is connected to a power supply (not shown) and is excited to generate an excitation magnetic flux. The ring-shaped detection coil 32 detects a detected magnetic flux and outputs the detected magnetic flux as a detected voltage. Further, the ring-shaped detection coil 32 is connected to a detection circuit (not shown), and the detection circuit detects a change in a detection voltage caused by a change in a detected magnetic flux. A gap 40 is formed between the magnetostrictive member 21 and the ring-shaped coil 30. The gap 40 is provided with a magnetic shield member 50 made of a ferromagnetic material such as iron in order to cut off a magnetic flux between the magnetostrictive member 21 and the annular coil 30. Since the magnetic shield member 50 is attached so as to be fixed to the annular coil 30, the magnetic shield member 50 does not rotate with the rotation shaft 20. The magnetic shield member 50 may be formed of a material capable of blocking magnetic flux, and may be formed of, for example, permalloy other than iron.

  FIG. 2 is a left side view of the strain sensor 10 shown in FIG. As shown in FIG. 2, the ring-shaped coil 30 is disposed so that its center axis A is inclined with respect to the axial direction B of the rotating shaft 20. That is, the center axis A of the annular coil is arranged so as not to be parallel or perpendicular to the axial direction B of the rotating shaft 20. The angle of the center axis A of the ring-shaped coil 30 with respect to the axial direction B of the rotating shaft 20 is, as shown in the operation of the strain sensor 10 of this embodiment described later, applied to the rotating shaft 20 from outside. , The magnetic domain rotation direction C or the magnetic domain alignment direction D due to the Villari effect in the magnetostrictive material portion 21, the excitation magnetic flux E interlinked with the annular excitation coil 31, and the detection interlinked with the annular detection coil 32. The ring-shaped coil 30 is arranged such that the direction of the magnetic flux F is parallel or vertical.

  FIG. 3 is a plan view of the strain sensor 10 shown in FIG. As shown in FIGS. 1 to 3, the magnetic shield member 50 is formed on a part of the entire circumference in the circumferential direction of the rotating shaft 20. More specifically, the rotating shaft 20 has one end located on the upper side in FIG. 1 and the other end located on the lower side, and the annular coil 30 is attached to one end. It has a first position 30a closest to it and a second position 30b closest to the other end. As shown in FIG. 3, when the gap 40 between the magnetostrictive member 21 and the annular coil 30 is viewed from the axial direction B, the magnetic shield member 50 It is provided in the right region G between the position closest to the first position 30a and the position closest to the second position 30b. Accordingly, as shown in FIGS. 1 to 3, the magnetic shield member 50 shields magnetic flux between the rotation shaft 20 and the ring-shaped coil 30 in a region corresponding to a half circumference of the rotation shaft 20 of the strain sensor 10. It is provided to be. On the other hand, the magnetic shield member 50 is located in the left region H between the position closest to the first position 30a and the position closest to the second position 30b of the gap 40 in the circumferential direction of the rotation shaft 20. Since it is not provided, the magnetic flux is not shielded.

Next, the operation of the strain sensor 10 according to this embodiment will be described.
When strain is measured by the strain sensor 10, an alternating current is applied to the ring-shaped exciting coil 31, and the exciting magnetic flux E interlinking with the ring-shaped exciting coil 31 is generated. The exciting magnetic flux E penetrates through the magnetostrictive member 21 in the region H where the exciting magnetic flux E is not blocked by the magnetic shield member 50, and the magnetostrictive member 21 is given magnetic anisotropy. . Therefore, the magnetostrictive member 21 in the region H where the exciting magnetic flux E is not blocked by the magnetic shield member constitutes an anisotropy imparting member.

  At this time, if the magnetic shield member 50 is not provided in the strain sensor 10, the magnetostrictive material portion 21 is given anisotropy in a direction opposite to that of the region H in the region G, and the ring-shaped detection coil is provided. The value of the detected magnetic flux F of 32 is opposite to that of the area H. Therefore, the detected magnetic flux F in the region G and the region H becomes 0 as a whole, and the distortion of the magnetostrictive member 21 cannot be detected. However, since the magnetic shield member 50 is provided in the strain sensor 10, the exciting magnetic flux E between the magnetostrictive member 21 and the ring-shaped coil 30 is cut off in the region G, The material portion 21 is not provided with magnetic anisotropy. Therefore, the magnetostrictive member 21 in the region G where the exciting magnetic flux E is blocked by the magnetic shield member 50 does not constitute an anisotropy imparting member. Further, in the area G, the detected magnetic flux F by the ring-shaped detection coil 32 is also shut off, so that it is not detected.

  When no force is applied to the rotating shaft 20 from the outside, in the region H where the magnetic shield member 50 is not provided, the exciting magnetic flux E generated by the annular exciting coil 31 is applied to the magnetostrictive member 21. And is detected by the annular detection coil 32 as the detection magnetic flux F. In the region G where the magnetic shield member is provided, the exciting magnetic flux E generated by the annular exciting coil 31 is not detected by the annular detecting coil 32 as the detected magnetic flux F. Therefore, the detection circuit connected to the ring-shaped detection coil 32 detects only the voltage generated in the ring-shaped detection coil 32 by the detected magnetic flux F in the region H.

  Next, when a counterclockwise force is applied to the rotating shaft 20 from the outside, the rotating shaft 20 is distorted, so that the magnetostrictive member 21 is distorted. Then, as shown in FIG. 2, a vignetting effect occurs due to the distortion, and the magnetic domains of the magnetostrictive member 21 are aligned in the magnetic domain alignment direction D. As a result, the magnetic permeability of the magnetostrictive member 21 changes with respect to the case where no force is applied to the rotating shaft 20. Due to the change in the magnetic permeability, the detected magnetic flux F changes, whereby the impedance of the annular detection coil 32 changes. Due to this change in impedance, the output signal voltage of the annular detection coil 32 changes, and the detection circuit detects the changed output signal voltage. A change in the value of the output signal voltage when no force is applied to the rotation shaft 20 from the outside and a change in the output signal voltage value when a force is applied to the rotation shaft 20 counterclockwise from the outside are measured. Thus, the detection circuit can detect the direction and magnitude of the distortion generated in the magnetostrictive member 21 and the rotating shaft 20.

  At this time, the magnetic domain alignment direction D is parallel to the directions of the excitation magnetic flux E and the detection magnetic flux F. Therefore, in the region H, compared with the case where the magnetic domain alignment direction D is not parallel to the directions of the exciting magnetic flux E and the detected magnetic flux F, the detected magnetic flux The change in F is detected with higher sensitivity and higher accuracy as a change in the impedance of the ring-shaped detection coil 32.

  On the other hand, when a force is applied clockwise from the outside to the rotating shaft 20, distortion occurs in the rotating shaft 20, causing distortion in the magnetostrictive material portion 21. Then, as shown in FIG. 2, a vignetting effect occurs due to the distortion, and the magnetic domains of the magnetostrictive member 21 rotate in the direction of the magnetic domain rotation direction C. As a result, the magnetic permeability of the magnetostrictive member 21 changes with respect to the case where no force is applied to the rotating shaft 20. Due to the change in the magnetic permeability, the detected magnetic flux F changes, whereby the impedance of the annular detection coil 32 changes. Due to this change in impedance, the output signal voltage of the annular detection coil 32 changes, and the detection circuit detects the changed output signal voltage. The output signal voltage value when no force is applied to the rotating shaft 20 from the outside, and the output signal voltage value when a force is applied clockwise from the outside to the rotating shaft 20 are changed. It is possible to detect the direction and magnitude of the distortion generated in the magnetostrictive member 21 and the rotating shaft 20.

  At this time, the direction of the magnetic domain rotation C is perpendicular to the directions of the exciting magnetic flux E and the detected magnetic flux F. Therefore, in the region H, compared with the case where the magnetic domain alignment direction D is not perpendicular to the directions of the exciting magnetic flux E and the detected magnetic flux F, the detected magnetic flux The change in F is detected with higher sensitivity and higher accuracy as a change in the impedance of the ring-shaped detection coil 32.

  Thus, the rotating shaft 20, the magnetostrictive member 21 provided on the rotating shaft 20, the annular coil 30 provided on the outer peripheral side of the rotating shaft 20, the magnetostrictive member 21 and the annular member The magnetic shield member 50 that is provided between the coil 30 and blocks magnetic flux; the annular coil 30 includes the annular detection coil 32; and the center axis A of the annular coil 30 is the rotation axis. The magnetic shield member 50 is provided in a part of the rotating shaft 20 in the circumferential direction, so that it is anisotropic with respect to the magnetostrictive member 21. It is not necessary to perform processing for imparting the property, and the manufacturing cost and the number of manufacturing steps of the strain sensor 10 can be reduced.

  In addition, since the magnetostrictive material portion 21 of the rotating shaft 20 is not subjected to anisotropy by processing or the like, the magnetostrictive material portion 21 has a greater anisotropy than when the magnetostrictive material portion 21 is previously provided with anisotropy. The change in magnetic permeability due to the magnetostriction when distorted can be increased, and the sensitivity and accuracy of the distortion sensor 10 are improved.

  The ring-shaped coil 30 has the first position 30a closest to one end of the rotating shaft 20 and the second position 30b closest to the other end of the rotating shaft 20. The magnetic shield member 50 extends from a position closest to the first position 30a to a position closest to the second position 30b in the circumferential direction of the rotary shaft 20 when viewed from the axial direction B of the rotary shaft 20. Since it is provided in the region G between the regions G, it is possible to prevent the anisotropy in a direction opposite to the region H from being given to the magnetostrictive material portion 21 in the region G, and to perform the detection in the region H. The distortion of the magnetostrictive member 21 can be detected by measuring the magnetic flux F. Thereby, the distortion of the magnetostrictive member 21 can be detected without providing a plurality of magnetostrictive members having different anisotropy, so that the space of the strain sensor 10 can be reduced and the cost can be reduced.

  Further, the direction of the magnetic domain rotation direction C of the magnetostrictive member portion 21 due to the distortion generated in the rotating shaft 20 when a force is applied to the rotating shaft 20 and the direction of the detected magnetic flux F interlinked with the annular detection coil 32. Are provided so as to be coincident with or orthogonal to each other, and the annular coil 30 is provided in the magnetic domain of the magnetostrictive material portion 21 due to a distortion generated in the rotating shaft 20 when a force is applied to the rotating shaft 20. Since the alignment direction D and the direction of the detection magnetic flux F linked to the ring-shaped detection coil 32 are provided so as to coincide with or orthogonal to each other, the sensitivity and accuracy of the strain sensor 10 can be improved.

  Further, since the magnetostrictive member 21 is made of a material different from that of the rotating shaft 20, the magnetostrictive member 21 having a large change in magnetic permeability is used while securing strength by using a material having a high composition for the rotating shaft 20. Therefore, the sensitivity and accuracy of the strain sensor 10 can be improved.

  In this embodiment, the annular coil 30 has the annular exciting coil 31 and the annular detecting coil 32, the annular exciting coil 31 generates the exciting magnetic flux E, and the annular detecting coil 32 Although the magnetic flux F is detected, the annular coil 30 may include only the annular detection coil 32. In this case, the ring-shaped detection coil 32 is connected to a power supply (not shown) and is excited, and the detected magnetic flux F changes due to a change in the magnetic permeability of the magnetostrictive member 21, thereby changing the impedance of the ring-shaped detection coil 32. . Then, the output signal voltage of the ring-shaped detection coil 32 changes due to the change in impedance, and the detection circuit detects the change in the output signal voltage. In addition, the direction and magnitude of the distortion generated in the rotating shaft 20 can be detected.

In this embodiment, when a force is applied to the rotating shaft 20 counterclockwise from the outside, the magnetic domain alignment direction D is parallel to the directions of the exciting magnetic flux E and the detected magnetic flux F, and the rotating shaft 20 When a force is applied clockwise to the outside 20 from the outside, the magnetic domain rotation direction C is perpendicular to the directions of the excitation magnetic flux E and the detection magnetic flux F, but the rotation axis 20 is counterclockwise from the outside. When a force is applied, the magnetic domain alignment direction D is perpendicular to the directions of the exciting magnetic flux E and the detected magnetic flux F, and when a force is applied to the rotating shaft 20 clockwise from outside, the magnetic domain rotating direction is changed. C and the directions of the excitation magnetic flux E and the detection magnetic flux F may be parallel.
When a force is applied to the rotating shaft 20 counterclockwise from the outside, the magnetic domain rotation direction C is parallel to the directions of the exciting magnetic flux E and the detected magnetic flux F, and the rotating shaft 20 is clockwise rotated from the outside. May be perpendicular to the magnetic domain alignment direction D and the directions of the excitation magnetic flux E and the detection magnetic flux F.
Further, when a force is applied to the rotating shaft 20 counterclockwise from the outside, the magnetic domain rotation direction C is perpendicular to the directions of the exciting magnetic flux E and the detection magnetic flux F, and the rotating shaft 20 is clockwise rotated from the outside. , The direction of the magnetic domain alignment D may be parallel to the directions of the excitation magnetic flux E and the detection magnetic flux F.

  Further, when a force is applied to the rotating shaft 20 from the outside, the magnetic domain alignment direction D and the directions of the exciting magnetic flux E and the detected magnetic flux F do not have to be completely parallel or perpendicular to each other. The direction of the magnetic domain rotation C and the directions of the excitation magnetic flux E and the detection magnetic flux F need not be completely parallel or perpendicular to each other when a force is applied from the outside. At least the directions of the exciting magnetic flux E and the detected magnetic flux F need not be completely parallel or perpendicular to the axial direction B of the rotating shaft 20.

  Further, in this embodiment, the magnetic shield member 50 is provided in the entire area of the area G corresponding to a half circumference of the rotation shaft 20 of the strain sensor 10, but is provided in a part of the area G. Is also good. Further, in this embodiment, the magnetic shield member 50 is provided in the area G, and the annular detection coil 32 detects the detected magnetic flux F in the area H. And the annular detection coil 32 may detect the detected magnetic flux F in the region G. Further, the magnetic shield member 50 may be provided in the whole range of the region G and a part of the region H, or may be provided in the whole range of the region H and a part of the region G.

  The structure of the strain sensor according to the present invention is as follows. That is, the rotating shaft 20, the magnetostrictive member 21 provided on the rotating shaft 20, the ring-shaped coil 30 provided on the outer peripheral side of the rotating shaft 20, the magnetostrictive member 21 and the ring-shaped coil 30 And the magnetic shield member 50 that blocks magnetic flux. The annular coil 30 includes the annular detection coil 32, and the center axis A of the annular coil 30 is the rotation axis 20 of the rotating shaft 20. The magnetic shield member 50 is provided so as to be oblique with respect to the axial direction B, and the magnetic shield member 50 is provided in a part of the rotating shaft 20 in the circumferential direction. It has the first position 30a closest to one end of the rotating shaft 20 and the second position 30b closest to the other end of the rotating shaft 20, and the magnetic shield member 50 20 said axes When viewed from the direction B, it is provided between a position closest to the first position 30a and a position closest to the second position 30b in the circumferential direction of the rotating shaft 20. The ring-shaped coil 30 is configured such that the magnetic domain rotation direction C of the magnetostrictive member portion 21 due to distortion generated in the rotation shaft 20 when a force is applied to the rotation shaft 20 and the detected magnetic flux linked to the ring-shaped detection coil 32. The direction of F is provided so as to be coincident or orthogonal, and the ring-shaped coil 30 is configured such that the magnetostriction caused by the distortion generated in the rotating shaft 20 when a force is applied to the rotating shaft 20. The magnetic domain alignment direction D of the material portion 21 and the direction of the detection magnetic flux F interlinked with the ring-shaped detection coil 32 are provided so as to match or be orthogonal to each other. Is It is composed of a material different from the rolling axis 20.

  The strain sensor structure according to the present invention includes a rotating shaft, a magnetostrictive member provided on the rotating shaft, a ring-shaped coil provided on the outer peripheral side of the rotating shaft, and a magnetic flux provided between the magnetostrictive member and the ring-shaped coil. And a magnetic shield member that blocks the rotation, the annular coil has an annular detection coil, and the central axis of the annular coil is provided so as to be oblique to the axial direction of the rotation axis. Since the strain sensor is provided at a part in the circumferential direction of the shaft, the manufacturing cost and the number of manufacturing steps of the strain sensor can be reduced.

Reference Signs List 20 rotation axis 30 ring-shaped coil 30a first position 30b second position 32 ring-shaped detection coil 50 magnetic shield member A center axis B axis direction C domain rotation direction D domain alignment direction F detection magnetic flux

Claims (5)

A rotating shaft (20);
A magnetostrictive member (21) provided on the rotating shaft (20),
An annular coil (30) provided on the outer peripheral side of the rotating shaft (20);
A magnetic shield member (50) provided between the magnetostrictive member (21) and the ring-shaped coil (30) to block magnetic flux;
The annular coil (30) includes:
A ring-shaped detection coil (32);
A center axis (A) of the ring-shaped coil (30) is provided so as to be oblique to an axial direction (B) of the rotating shaft (20);
The said magnetic shield member (50) is provided in a part of circumferential direction of the said rotating shaft (20), The distortion sensor structure characterized by the above-mentioned. The annular coil (30) has a first position (30a) closest to one end of the rotating shaft (20) and a second position (30b) closest to the other end of the rotating shaft (20). And
The magnetic shield member (50) is located at a position closest to the first position (30a) in a circumferential direction of the rotating shaft (20) when viewed from the axial direction (B) of the rotating shaft (20). The strain sensor structure according to claim 1, wherein the strain sensor is provided between the second position and a position closest to the second position. The annular coil (30) includes:
The magnetic domain rotation direction (C) of the magnetostrictive member portion (21) due to the strain generated on the rotating shaft (20) when a force is applied to the rotating shaft (20), and the annular detection coil (32) interlinks. The strain sensor structure according to claim 1, wherein the direction of the detected magnetic flux (F) is provided so as to coincide with or orthogonal to the direction. The annular coil (30) includes:
The magnetic domain alignment direction (D) of the magnetostrictive member portion (21) due to the strain generated on the rotating shaft (20) when a force is applied to the rotating shaft (20), and the annular detection coil (32) interlinks. The strain sensor structure according to claim 1, wherein the direction of the detected magnetic flux (F) is provided so as to coincide with or orthogonal to the direction.   The strain sensor structure according to any one of claims 1 to 4, wherein the magnetostrictive member (21) is made of a different material from the rotating shaft (20).

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