JP2017067547A - Magnetic shield structure and sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress stress, generated through expansion and contraction of a housing and a magnetic shield member, from concentrating on a particular part.SOLUTION: A torque detection device comprises: a housing 11 in which a sensor unit 20 detecting variation of magnetism to be detected is provided and which is made of resin; and a magnetic shield member 26 which is provided at an outer periphery of the sensor unit 20 and made of metal having a different coefficient of thermal expansion from the housing 11. The magnetic shield member 26 has a plurality of magnetic shield pieces 27, 28 and 29 having both ends on both peripheral sides of the sensor unit 20, the plurality of magnetic shield pieces 27, 28 and 29 being provided side by side in a peripheral direction of an outer periphery of the sensor unit 20.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a magnetic shield structure and a sensor device.

  As a magnetic shield structure in which a magnetic shield member is provided so as to cover the outer periphery of a detection unit that detects magnetism in a sensor device that detects a change in magnetism, for example, there is one described in Patent Document 1. Patent Document 1 discloses a torque sensor that detects a torque applied to an input shaft by detecting a change in magnetism due to a relative angular displacement between the input shaft and the output shaft. In such a torque sensor, a magnetic shield member that covers the outer circumferences of two coils that detect magnetism related to the relative angular displacement between an input shaft and an output shaft is integrated with a housing made of synthetic resin.

Japanese Patent No. 5508826

  By the way, a housing made of synthetic resin repeats expansion and contraction when temperature changes occur repeatedly in the surroundings. However, when electromagnetic steel plate or permalloy or the like (metal) is used as the magnetic shield member as in the above-mentioned Patent Document 1, since the thermal expansion coefficient of the metal is smaller than that of the synthetic resin, the temperature change repeatedly occurs in the surroundings. However, the expansion and contraction of the housing is hindered by the magnetic shield member. In this case, if the stress generated based on the expansion and contraction of the housing is, for example, Patent Document 1, a part of the end portion of the small-diameter cylindrical portion or the end portion of the flange portion of the magnetic shield member that makes contact with the housing. There is a possibility of concentrating on the site.

  This invention is made | formed in view of such a situation, The objective can suppress that the stress which arises based on expansion | swelling and shrinkage | contraction of a housing or a magnetic-shielding member concentrates on a one part site | part. The object is to provide a magnetic shield structure and a sensor device.

  A magnetic shield structure that solves the above problems includes a housing in which a detection unit for detecting a change in magnetism in a detection target is provided, and a magnet made of a material that is provided on the outer periphery of the detection unit and has a different thermal expansion coefficient from the housing. A shield member, and the magnetic shield member is integrated with the housing. In the magnetic shield structure, the magnetic shield member has a plurality of magnetic shield pieces having end portions on both sides in the circumferential direction, and the plurality of magnetic shield pieces extend along the circumferential direction of the outer periphery of the detection unit. They are arranged side by side.

  According to the above configuration, the end of the magnetic shield piece can come into contact with the housing. For this reason, the number of the end portions where stress generated due to expansion and contraction of the housing and the magnetic shield member in the magnetic shield member is concentrated is such that a plurality of magnetic shield pieces are integrated and only one end portion on each side in the circumferential direction. It will increase compared to the case where it does not exist. Thereby, the stress generated based on the expansion and contraction of the housing and the magnetic shield member due to the repeated temperature change in the surroundings can be distributed and applied to the end portions of the plurality of magnetic shield pieces constituting the magnetic shield member. it can. Therefore, it can suppress that the stress which arises based on the expansion | swelling and shrinkage | contraction of a housing or a magnetic shielding member concentrates on a one part site | part.

  On the other hand, if the stress caused by the expansion and contraction of the housing and the magnetic shield member is only suppressed from being concentrated on a part of the housing, the strength of the housing is increased by increasing the size of the housing. It is also possible to do. On the other hand, according to the said structure, since it is not necessary to raise the intensity | strength of a housing, it is effective also from a viewpoint of suppressing the enlargement of a housing.

  By the way, when the magnetic shield member is composed of a plurality of magnetic shield pieces as in the above configuration, magnetism from other than the detection target is generated in the region where the detection unit is provided through the joint between the adjacent magnetic shield pieces. There is a possibility of intrusion.

  Therefore, for example, among the plurality of magnetic shield pieces, the respective end portions facing each other between the adjacent magnetic shield pieces are provided in a state of overlapping and contacting in the direction of approaching or separating from the detection unit, or Of the plurality of magnetic shield pieces, it is desirable that each of the end portions facing each other between adjacent magnetic shield pieces is provided in a state of being overlapped and separated in a direction approaching or separating from the detection unit.

  According to the above configuration, the magnetic shield member can cover the entire outer periphery of the detection unit when viewed from the side away from the detection unit, and from other than the detection target in the region where the detection unit is provided. The magnetic intrusion can be shielded. Therefore, it is possible to effectively suppress the influence of magnetism from other than the detection target on the detection unit, while suppressing the stress generated based on the expansion and contraction of the housing and the magnetic shield member from being concentrated on some parts. .

  In addition, among the plurality of magnetic shield pieces, each of the end portions facing each other between adjacent magnetic shield pieces has a gap that is not larger than a size capable of shielding magnetism from other than the detection target and has a circumference around the outer periphery of the detection unit. You may make it provide in the state arranged along the direction.

  According to the above configuration, each of the end portions facing each other between the adjacent magnetic shield pieces has a gap in the circumferential direction of the outer periphery of the detection unit. The size is such that can be shielded. In other words, the magnetic shield member cannot cover the entire outer periphery of the detection unit when viewed from the side away from the detection unit, but the magnetic shield member from the area other than the detection target in the region where the detection unit is provided. Intrusion can be shielded. Further, the magnetic shield piece can be expanded and contracted and moved in the circumferential direction of the outer periphery of the detection unit using the gap (a space formed by the gap). That is, the stress generated based on the expansion and contraction of the housing and the magnetic shield member can be absorbed by the gap. Therefore, it is possible to effectively suppress the influence of magnetism from other than the detection target on the detection unit while suppressing the stress generated based on the expansion and contraction of the housing from being concentrated on a part of the part.

  In addition, among the plurality of magnetic shield pieces, a space surrounded by other magnetic shield pieces is provided between the opposing end portions between the adjacent magnetic shield pieces. The end portions that face each other may be provided in a state of being inserted into the space so as to be movable along the circumferential direction of the outer periphery of the detection portion.

  According to the said structure, each edge part which opposes between adjacent magnetic shield pieces comes to make the magnetic shield structure connected with other magnetic shield pieces. That is, the magnetic shield member moves the space surrounded by the other magnetic shield pieces in the circumferential direction of the outer periphery of the detection unit, thereby detecting the detection unit according to the expansion and contraction of the housing and the magnetic shield member. It can be expanded and contracted in the circumferential direction of the outer periphery. Therefore, stress generated based on the expansion and contraction of the housing and the magnetic shield member due to repeated temperature changes in the surroundings can be absorbed even by the expansion and contraction of the magnetic shield member.

  The magnetic shield member can cover the entire circumference of the outer periphery of the detection unit when viewed from the side close to or away from the detection unit, and the magnetic shield member from the area other than the detection target in the region where the detection unit is provided. Intrusion can be shielded. Therefore, it is possible to effectively suppress the influence of magnetism from other than the detection target on the detection unit while effectively suppressing the stress caused by the expansion and contraction of the housing and the magnetic shield member from concentrating on some parts. be able to.

  Such a magnetic shield structure is desirably employed in a sensor device that specifically detects a change in magnetism caused by rotation of a rotation shaft to be detected by the detection unit.

  According to the above configuration, even when the housing and the magnetic shield member repeatedly expand and contract due to repeated temperature changes in the surroundings, the stress generated based on such expansion and contraction is concentrated on some parts. Can be suppressed. Therefore, it is possible to improve the reliability when the sensor device is used in an environment in which the housing and the magnetic shield member are repeatedly expanded and contracted due to repeated temperature changes in the surroundings.

  According to this invention, it can suppress that the stress which arises based on the expansion | swelling and shrinkage | contraction of a housing or a magnetic shielding member concentrates on a one part site | part.

The perspective view which shows the disassembled perspective structure of a torque sensor apparatus. The perspective view which shows the perspective structure of the sensor unit about a torque sensor apparatus. Sectional drawing which shows the III-III line | wire cross-sectional structure of FIG. 1 especially as a magnetic-shield structure in 1st Embodiment. Sectional drawing which shows the magnetic-shield structure in 2nd Embodiment. Sectional drawing which shows the magnetic-shield structure in 3rd Embodiment. The perspective view which shows the magnetic shield body in 4th Embodiment. Sectional drawing which shows the magnetic-shield structure in 4th Embodiment.

(First embodiment)
Hereinafter, a first embodiment of the magnetic shield structure and the sensor device will be described.
The magnetic shield structure of the present embodiment detects, for example, a rotation shaft such as a steering shaft in a vehicle including a torsion bar that connects an input shaft (upper side in FIG. 1) and an output shaft (lower side in FIG. 1). As described above, the present invention is employed in a torque detection device as a sensor device that detects the twist amount of the torsion bar.

  As shown in FIG. 1, the torque detection device 10 includes a housing 11 made of a resin such as a synthetic resin. The housing 11 is provided with a connector portion 12 so as to protrude to the outside. The connector portion 12 incorporates a circuit board or the like that enables transmission and reception of signals with the outside of the housing 11 (for example, a control device in a vehicle). A plurality of output pins 12 a are provided inside the connector portion 12. Each output pin 12a outputs a torque detection result to the outside.

  In addition, a unit accommodating portion 13 cut out in a cylindrical shape is provided inside the housing 11. The unit housing portion 13 is inserted with the input shaft and the output shaft, and houses a sensor unit 20 as a detecting portion, a magnet unit 30, and a magnetic yoke unit 40.

  The magnet unit 30 is externally fitted on the output shaft side of the input shaft so as to rotate integrally with the input shaft. The magnet unit 30 includes a cylindrical core 31 into which the input shaft is press-fitted. On the outer periphery of the core 31, a multipolar magnet 32 having N-pole and S-pole magnetic poles alternately in the circumferential direction of the core 31 is fixed. The multipolar magnet 32 forms a magnetic field around the input shaft.

  A magnetic yoke unit 40 is provided on the outer periphery of the magnet unit 30 with a predetermined gap in the radial direction of the magnet unit 30. The magnetic yoke unit 40 is fitted on the input shaft side of the output shaft so as to rotate integrally with the output shaft. The magnetic yoke unit 40 includes a cylindrical yoke holder 41. A first magnetic yoke 42 and a second magnetic yoke 43 made of a soft magnetic metal are integrated with the yoke holder 41. The magnetic yokes 42 and 43 are arranged to face each other with a predetermined gap in the axial direction of the yoke holder 41. A plurality of claw portions extending toward the opposing magnetic yoke are provided on the inner peripheral surface of each magnetic yoke 42, 43, and the claw portions of each magnetic yoke 42, 43 are arranged in the circumferential direction of the yoke holder 41. Alternatingly arranged.

  A sensor unit 20 is provided on the outer periphery of the magnetic yoke unit 40 with a predetermined gap in the radial direction of the magnetic yoke unit 40. The sensor unit 20 is integrated with the housing 11.

  As shown in FIG. 2, the sensor unit 20 includes an annular holder 21 made of a resin such as a synthetic resin. A C-shaped first magnetism collecting ring 22 and a second magnetism collecting ring 23 made of a soft magnetic metal are integrated with the inner circumference of the holder 21. Each of the magnetism collecting rings 22 and 23 is provided with a predetermined gap in the axial direction of the holder 21.

  Specifically, retaining portions 21 a and 21 b projecting inward in the radial direction of the holder 21 are provided on the inner periphery of the holder 21 with a predetermined gap in the axial direction of the holder 21. The retaining portions 21 a and 21 b are provided intermittently along the circumferential direction of the holder 21. In addition, a raised portion 21c that protrudes inward in the radial direction of the holder 21 is provided between the axial directions of the holders 21 in the retaining portions 21a and 21b. The raised portions 21 c are provided intermittently along the circumferential direction of the holder 21. Further, a groove portion 21 d having a depth in the radial direction of the holder 21 is continuously provided along the circumferential direction of the holder 21 on the outer periphery of the holder 21.

  A first magnetism collecting ring 22 is fitted and fixed between the retaining portion 21 a and the raised portion 21 c on the inner periphery of the holder 21. A second magnetism collecting ring 23 is fitted and fixed between the retaining portion 21 b and the raised portion 21 c on the inner periphery of the holder 21. Each of the magnetism collecting rings 22 and 23 is fixed with a predetermined gap in the axial direction of the holder 21.

  Two sets of terminals 22a and 23a that protrude outward in the radial direction of the magnetism collecting rings 22 and 23 and face in the axial direction are provided at portions of the magnetism collecting rings 22 and 23 that face the C-shaped joint. Yes. In the present embodiment, a magnetic circuit is constituted by the magnetism collecting rings 22 and 23 (sensor unit 20), the multipolar magnet 32 (magnet unit 30), and the magnetic yokes 42 and 43 (magnetic yoke unit 40).

  Between the two sets of terminals 22a and 23a of the magnetic flux collecting rings 22 and 23, magnetic sensors 24 and 25 each including a magnetic detection element such as a Hall IC are provided. Each of the magnetic sensors 24 and 25 detects the strength of magnetism applied by the magnetic circuit and outputs an electrical signal such as a voltage corresponding to the detected strength of magnetism. Each of the magnetic sensors 24 and 25 is electrically connected to a connector portion 12 (circuit board or the like) of the housing 11 through a connection line (not shown), and outputs the electric signal to the outside through the connector portion 12.

  A magnetic shield member 26 made of a soft magnetic metal that is a material having a thermal expansion coefficient different from that of the resin that is the material of the housing 11 is provided in the groove portion 21 d on the outer periphery of the holder 21. The magnetic shield member 26 includes a plurality of magnetic shield pieces such as two first magnetic shield pieces 27, one second magnetic shield piece 28, and two third magnetic shield pieces 29.

  As shown in FIGS. 2 and 3, one first magnetic shield piece 27 is provided on each side of the holder 21 in the two pairs of terminals 22 a and 23 a of the magnetism collecting rings 22 and 23 in the circumferential direction. Among the end portions 27a in the circumferential direction of the holder 21 in each first magnetic shield piece 27, the end portions 27a of the two sets 22a and 23a side of the magnetism collecting rings 22 and 23 have their tips at the diameter of the holder 21. It is extended in the circumferential direction in a state of being bent so as to face the inner side of the direction (the holder 21 side). As a result, at the end 27 a where the tip is bent, the stress generated based on the expansion and contraction of the housing 11 and the magnetic shield member 26 can be distributed and act in the radial direction and the circumferential direction of the holder 21. Therefore, the end 27a where the tip is bent is based on the expansion and contraction of the housing 11 and the magnetic shield member 26 as compared with the case where the tip is extended in the circumferential direction without being bent toward the holder 21 side. It is suppressed that the stress which arises concentrates on a part of edge part.

  The second magnetic shield pieces 28 are provided on the same circumference as the first magnetic shield pieces 27. Each end portion 28a in the circumferential direction of the holder 21 in the second magnetic shield piece 28 is located on the two terminals 22a and 23a side of the magnetic flux collecting rings 22 and 23 in each end portion 27a of each first magnetic shield piece 27. It faces each end portion 27a on a different side.

  One third magnetic shield piece 29 is provided between each first magnetic shield piece 27 and second magnetic shield piece 28. Each third magnetic shield piece 29 is on a different circumference from each of the first magnetic shield piece 27 and the second magnetic shield piece 28, that is, with respect to each of the first magnetic shield piece 27 and the second magnetic shield piece 28. It is shifted to the outside in the radial direction.

  In such a sensor unit 20, first, the holder 21 is resin-molded. Next, the magnetism collecting rings 22 and 23 are fixed to the holder 21 made of resin. Next, the sensor unit 20 is completed by disposing the magnetic sensors 24 and 25 between the two sets of terminals 22a and 23a of the magnetism collecting rings 22 and 23, respectively. The housing 11 is arranged in a state where the magnetic shield member 26 (each magnetic shield piece 27, 28, 29) is arranged together with the sensor unit 20 completed as described above in a resin molding die shaped like the housing 11. It is completed by being molded with resin. When the housing 11 is resin-molded, the magnetic sensors 24 and 25 are resin-molded in a state where they are disposed between the two sets of terminals 22a and 23a of the magnetism collecting rings 22 and 23, respectively. It is resin-molded in a state where it can be connected to the connector portion 12.

  In the present embodiment, for example, the holder 21 may be resin-molded together with the magnetism collecting rings 22 and 23 (two sets of terminals 22a and 23a). In this case, after the resin molding, the holder 21 can be sandwiched between the two pairs of terminals 22a and 23a of the magnetism collecting rings 22 and 23 so that the magnetic sensors 24 and 25 can be connected to the connector portion 12 of the housing 11. It suffices to be configured.

  Thereafter, in the housing 11 in which the sensor unit 20 is integrated, the magnet unit 30 and the magnetic yoke unit 40 assembled to each other are incorporated inside the sensor unit 20 together with the input shaft and the output shaft. Is completed.

Next, the configuration of the magnetic shield member 26 will be described in detail.
As shown in FIG. 3, in the resin-molded housing 11, the second magnetism collecting ring 23 is integrated with the housing 11. FIG. 3 shows a cross section including the center in the width direction of the second magnetism collecting ring 23 (the axial direction of the sensor unit 20) among the cross sections orthogonal to the axial direction of the sensor unit 20. In the resin-molded housing 11, the first magnetic flux collecting ring 22 is integrated with the housing 11 like the second magnetic flux collecting ring 23.

  Between the second magnetism collecting ring 23 and the holder 21, there is a portion where resin is interposed by resin molding of the housing 11. In the resin-molded housing 11, the first magnetic shield piece 27 and the third magnetic shield piece 29, and the second magnetic shield piece 28 and the third magnetic shield piece 29 are adjacent to each other in the circumferential direction of the sensor unit 20. It is integrated with the housing 11. Resin is interposed between the third magnetic shield piece 29 and the holder 21 by resin molding of the housing 11.

  Then, as shown in an enlarged view of FIG. 3 (upper side in FIG. 3), each end portion facing between the first magnetic shield piece 27 and the third magnetic shield piece 29 adjacent in the circumferential direction of the sensor unit 20. 27a and 29a are provided in a state where they overlap and abut in the radial direction of the sensor unit 20. The end portion 27a of the first magnetic shield piece 27 overlaps the end portion 29a of the third magnetic shield piece 29 in the range of the arc X of the sensor unit 20, and abuts on the inner side in the radial direction of the sensor unit 20 of the end portion 29a. It has a magnetic shield structure.

  Similarly, as shown in the enlarged view of FIG. 3 (lower side in FIG. 3), each end facing between the second magnetic shield piece 28 and the third magnetic shield piece 29 adjacent in the circumferential direction of the sensor unit 20. The portions 28 a and 29 a are provided in a state where they overlap and abut in the radial direction of the sensor unit 20. The end portion 28a of the second magnetic shield piece 28 overlaps the end portion 29a of the third magnetic shield piece 29 in the range of the arc X of the sensor unit 20, and abuts on the inner side in the radial direction of the sensor unit 20 of the end portion 29a. It has a magnetic shield structure.

According to the present embodiment described above, the following operations and effects are achieved.
(1) According to the present embodiment, the first magnetic shield piece 27, the second magnetic shield piece 28, and the end portions 27a, 28a, 29a of the third magnetic shield pieces 29 are brought into contact with the housing 11, respectively. It can be done. For this reason, the number of end portions of the magnetic shield member 26 where stress generated due to expansion and contraction of the housing 11 and the magnetic shield member 26 is concentrated is such that the magnetic shield pieces 27, 28, and 29 are integrated and the circumference of the sensor unit 20 is integrated. It will increase compared to the case where there is only one end on each side of the direction. As a result, stress generated based on expansion and contraction of the housing 11 and the magnetic shield member 26 due to repeated temperature changes in the surroundings is applied to each end of the plurality of magnetic shield pieces 27, 28, and 29 constituting the magnetic shield member 26. The portions 27a, 28a, and 29a can be dispersed and acted. Therefore, it can suppress that the stress which arises based on the expansion | swelling and shrinkage | contraction of the housing 11 or the magnetic shield member 26 concentrates on one part.

  On the other hand, if the stress caused by the expansion and contraction of the housing 11 and the magnetic shield member 26 is only to be suppressed from being concentrated on some parts, the strength of the housing 11 is increased by increasing the size of the housing 11 or the like. It is also conceivable to increase the value. On the other hand, according to the present embodiment, there is no need to increase the strength of the housing 11, which is effective from the viewpoint of suppressing the increase in the size of the housing 11.

  (2) By the way, when the magnetic shield member 26 is composed of a plurality of magnetic shield pieces 27, 28, and 29 as in the present embodiment, the sensor unit 20 is provided through a joint between adjacent magnetic shield pieces. There is also a possibility that magnetism from other than the detection target may enter the area (unit accommodating portion 13).

  In this regard, in the present embodiment, as shown in the enlarged view of FIG. 3, among the plurality of magnetic shield pieces 27, 28, and 29, each end portion facing between adjacent magnetic shield pieces is the sensor unit 20. They are provided so as to overlap and abut in the radial direction.

  That is, the magnetic shield member 26 can cover the entire outer circumference of the sensor unit 20 when viewed from the outside in the radial direction of the sensor unit 20, and from other than the detection target in the region where the sensor unit 20 is provided. Magnetic intrusion can be shielded. Therefore, it is possible to effectively suppress the influence of magnetism from other than the detection target on the sensor unit 20 while suppressing the stress generated based on the expansion and contraction of the housing 11 and the magnetic shield member 26 from concentrating on some parts. be able to.

  (3) The torque detector 10 employs a magnetic shield structure as shown in the enlarged view of FIG. Therefore, even when the housing 11 and the magnetic shield member 26 are repeatedly expanded and contracted due to repeated temperature changes around the torque detection device 10, the stress generated based on the expansion and contraction is applied to some parts. Concentration can be suppressed. Therefore, it is possible to improve reliability when the torque detection device 10 is used in an environment in which the housing 11 and the magnetic shield member 26 are repeatedly expanded and contracted due to repeated temperature changes in the surroundings.

(Second Embodiment)
Next, a second embodiment of the magnetic shield structure and the torque detection device will be described. In addition, the same structure as embodiment already demonstrated attaches | subjects the same code | symbol, and the duplicate description is abbreviate | omitted.

  As shown in FIG. 4 and an enlarged view of FIG. 4 (upper side in FIG. 4), each end facing between the first magnetic shield piece 27 and the third magnetic shield piece 29 adjacent in the circumferential direction of the sensor unit 20. The portions 27a and 29a are provided so as to overlap and be separated from each other in the radial direction of the sensor unit 20. The end portion 27a of the first magnetic shield piece 27 overlaps with the end portion 29a of the third magnetic shield piece 29 in the range of the arc X of the sensor unit 20, and is inward of the sensor unit 20 in the radial direction with respect to the end portion 29a. A magnetic shield structure having a gap Y is formed.

  Similarly, as shown in FIG. 4 and an enlarged view of FIG. 4 (lower side in FIG. 4), the second magnetic shield piece 28 and the third magnetic shield piece 29 that are adjacent in the circumferential direction of the sensor unit 20 face each other. The end portions 28a and 29a are provided so as to overlap and be separated from each other in the radial direction of the sensor unit 20. The end portion 28a of the second magnetic shield piece 28 overlaps the end portion 29a of the third magnetic shield piece 29 within the range of the arc X of the sensor unit 20, and is located on the inner side in the radial direction of the sensor unit 20 with respect to the end portion 29a. A magnetic shield structure having a gap Y is formed.

  The gap Y is set to a size that can shield magnetism from other than the detection target that attempts to enter the region (unit housing portion 13) where the sensor unit 20 is provided through diffraction.

According to this embodiment described above, in addition to the actions and effects corresponding to the actions and effects (1) and (3) of the first embodiment, the following actions and effects can be achieved.
(4) As shown in the enlarged view of FIG. 4, in the present embodiment, the opposing ends between adjacent magnetic shield pieces are in a state of being separated in the radial direction of the sensor unit 20. Are overlapped with each other in the range of the arc X in the radial direction.

  That is, the magnetic shield member 26 can cover the entire outer circumference of the sensor unit 20 when viewed from the outside in the radial direction of the sensor unit 20, and from other than the detection target in the region where the sensor unit 20 is provided. Magnetic intrusion can be shielded. Therefore, it is possible to effectively suppress the influence of magnetism from other than the detection target on the sensor unit 20 while suppressing the stress generated based on the expansion and contraction of the housing 11 and the magnetic shield member 26 from concentrating on some parts. be able to.

(Third embodiment)
Next, a third embodiment of the magnetic shield structure and the torque detection device will be described. In addition, the same structure as embodiment already demonstrated attaches | subjects the same code | symbol, and the duplicate description is abbreviate | omitted.

As shown in FIG. 5, the third magnetic shield piece 29 of the present embodiment is provided on the same circumference as the first magnetic shield piece 27 and the second magnetic shield piece 28.
Specifically, as shown in the enlarged view of FIG. 5 (upper side in FIG. 5), each of the opposing first magnetic shield pieces 27 and the third magnetic shield pieces 29 that are adjacent in the circumferential direction of the sensor unit 20. The end portions 27 a and 29 a are provided side by side with a gap in the circumferential direction of the sensor unit 20. The end portion 27 a of the first magnetic shield piece 27 has a magnetic shield structure that is aligned with the end portion 29 a of the third magnetic shield piece 29 with a gap Z in the circumferential direction of the sensor unit 20.

  Similarly, as shown in the enlarged view of FIG. 5 (the lower side in FIG. 5), each end facing between the second magnetic shield piece 28 and the third magnetic shield piece 29 adjacent in the circumferential direction of the sensor unit 20. The portions 28 a and 29 a are provided side by side with a gap in the circumferential direction of the sensor unit 20. The end 28 a of the second magnetic shield piece 28 has a magnetic shield structure that is aligned with the end 29 a of the third magnetic shield piece 29 with a gap Z in the circumferential direction of the sensor unit 20.

  The gap Z is set to a size that can shield magnetism from other than the detection target that attempts to enter the region (unit housing portion 13) in which the sensor unit 20 is provided through diffraction.

According to this embodiment described above, in addition to the actions and effects corresponding to the actions and effects (1) and (3) of the first embodiment, the following actions and effects can be achieved.
(5) As shown in the enlarged view of FIG. 5, in the present embodiment, each of the end portions facing each other between the adjacent magnetic shield pieces has a gap Z in the circumferential direction of the sensor unit 20. The size of the gap Z is set to a size that can shield magnetism from other than the detection target in the area where the sensor unit 20 is provided.

  That is, the magnetic shield member 26 does not cover the entire outer periphery of the sensor unit 20 when viewed from the outside in the radial direction of the sensor unit 20, but from other than the detection target in the region where the sensor unit 20 is provided. The magnetic intrusion can be shielded. Further, each magnetic shield piece 27, 28, 29 can be expanded and contracted and moved in the circumferential direction of the sensor unit 20 using the space between the gaps Z (the space formed by the gaps Z). That is, the stress generated based on the expansion and contraction of the housing 11 and the magnetic shield member 26 can be absorbed by the gap Z. Therefore, it is possible to effectively suppress the influence of magnetism from other than the detection target on the sensor unit 20 while suppressing the stress generated based on the expansion and contraction of the housing 11 and the magnetic shield member 26 from concentrating on some parts. be able to.

(Fourth embodiment)
Next, a magnetic shield structure and a torque detection device according to a fourth embodiment will be described. In addition, the same structure as embodiment already demonstrated attaches | subjects the same code | symbol, and the duplicate description is abbreviate | omitted.

  As shown in FIG. 6, the magnetic shield member 26 of the present embodiment is surrounded by a third magnetic shield piece 29 that is another magnetic shield piece from the magnetic shield pieces 27 and 28 adjacent in the circumferential direction of the sensor unit 20. And a magnetic shield body 50 having a space 29b defined. The magnetic shield body 50 has a box shape that opens at both end portions 29a in the circumferential direction of the holder 21 of the third magnetic shield piece 29 that defines the space 29b. The space 29 b has a length on the long side in the axial direction of the holder 21 that substantially matches the axial length of the holder 21 in the first magnetic shield piece 27 and the second magnetic shield piece 28, and the radial direction of the holder 21. The length of the short side is set so as to substantially match the radial thickness of the holder 21 in the first magnetic shield piece 27 and the second magnetic shield piece 28.

  That is, as shown in FIG. 7, in the resin-molded housing 11, the first magnetic shield piece 27 and the second magnetic shield piece 28 are adjacent to each other in the circumferential direction of the sensor unit 20 and integrated with the housing. . Between the end portions 27 a and 28 a facing each other between the adjacent magnetic shield pieces 27 and 28, a magnetic shield body 50 is provided and a space 29 b defined by the third magnetic shield piece 29 is provided. It has been. In each of the end portions 29a (openings) on both sides in the circumferential direction of the holder 21 in the magnetic shield body 50, a part of each end portion 27a, 28a facing each other between the adjacent magnetic shield pieces 27, 28 is inserted. Yes.

  Specifically, as shown in the enlarged view of FIG. 7, the end portions 27 a and 28 a facing each other between the adjacent magnetic shield pieces 27 and 28 are movable along the circumferential direction of the sensor unit 20. It is provided in a state of being inserted inside. The end portions 27 a and 28 a facing each other between the adjacent magnetic shield pieces 27 and 28 form a magnetic shield structure that is inserted into the space 29 b of the magnetic shield body 50 within the range of the arc X of the sensor unit 20. .

  In the arc X of this embodiment, even if the housing 11 and the magnetic shield member 26 expand and contract, the end portions 27a and 28a facing each other between the adjacent magnetic shield pieces 27 and 28 are inserted into the space 29b. It is set to a size that can maintain the maintained state.

According to this embodiment described above, in addition to the actions and effects corresponding to the actions and effects (1) and (3) of the first embodiment, the following actions and effects can be achieved.
(6) As shown in the enlarged view of FIG. 7, in this embodiment, the end portions 27 a, 28 a facing each other between the adjacent magnetic shield pieces 27, 28 are the magnetic shield bodies 50 (third magnetic shield pieces 29). ) Are connected to each other.

  In other words, the magnetic shield member 26 responds to the expansion and contraction of the housing 11 and the magnetic shield member 26 by the adjacent magnetic shield pieces 27 and 28 moving in the circumferential direction of the sensor unit 20 through the space 29 b of the magnetic shield body 50. The sensor unit 20 can be expanded and contracted in the circumferential direction. Therefore, the stress generated based on the expansion and contraction of the housing 11 and the magnetic shield member 26 due to repeated temperature changes in the surroundings can be absorbed by the expansion and contraction of the magnetic shield member 26 in the circumferential direction of the sensor unit 20. .

  Further, the magnetic shield member 26 can cover the entire outer periphery of the sensor unit 20 when viewed from the outside in the radial direction of the sensor unit 20, so that the magnetic shield member 26 can be protected from a region other than the detection target in the region where the sensor unit 20 is provided. Magnetic intrusion can be shielded. Therefore, it is possible to effectively suppress the influence of magnetism from other than the detection target on the sensor unit 20 while effectively suppressing the stress caused by the expansion and contraction of the housing 11 and the magnetic shield member 26 from being concentrated on a part of the site. Can be suppressed.

In addition, each said embodiment can also be implemented with the following forms which changed this suitably.
In the first to third embodiments, the arrangement of the first magnetic shield piece 27, the second magnetic shield piece 28, and the third magnetic shield piece 29 is arranged by replacing the inside and outside of the sensor unit 20 in the radial direction. May be.

  In each embodiment, the material of each magnetic shield piece 27, 28, 29 may be a material having a thermal expansion coefficient different from that of the housing 11, and may be a resin not limited to a soft magnetic metal. Moreover, the material of the housing 11 should just be a material which has a thermal expansion coefficient different from each magnetic shield piece 27,28,29, and may be not only a resin but a metal.

  In each embodiment, the number of magnetic shield pieces may be increased. For example, the first magnetic shield piece 27 and the second magnetic shield piece 28 may be divided into two or three. In this case, a third magnetic shield piece 29 and a magnetic shield body 50 are additionally provided between the divided first or second magnetic shield piece 27 or second magnetic shield piece 28. You can do it. This makes it possible to more suitably disperse the stress generated based on the expansion and contraction of the housing 11 and the magnetic shield member 26 caused by repeated temperature changes in the surroundings.

  In each embodiment, the range of the arc X of the sensor unit 20, the radial gap Y of the sensor unit 20, and the circumferential gap Z of the sensor unit 20 are within the region where the sensor unit 20 is provided as a magnetic shield structure. You may change in the range which can shield the magnetic penetration | invasion from other than the detection target to. For example, in the third embodiment, the circumferential gap Z of the sensor unit 20 is large enough to shield magnetism from other than the detection target that attempts to enter through the diffraction into the area where the sensor unit 20 is provided. It only has to be set as follows.

  In the magnetic shield structure of each embodiment, a device such as arranging each end of adjacent magnetic shield pieces so as to overlap in the radial direction of the sensor unit 20 has been applied in the circumferential direction of the sensor unit 20. Can be applied in the axial direction of the sensor unit 20, or can be applied in both the circumferential direction and the axial direction of the sensor unit 20. This makes it possible to more suitably disperse the stress generated based on the expansion and contraction of the housing 11 and the magnetic shield member 26 caused by repeated temperature changes in the surroundings.

  -Although the example which uses Hall IC in order to detect the change of magnetism was explained about the magnetic shield structure of each embodiment, it was not restricted to this but other systems, such as a sensor using an MR element, and a resolver, were used. It can also be applied to sensors.

  In the magnetic shield structure of each embodiment, the example of the method of providing the magnetic sensor around the rotation axis as a detection target has been described, but not limited to this, it faces the axial end of the rotation axis. Thus, the present invention can also be applied to a method of providing another magnetic sensor such as providing a magnetic sensor.

  -Although the magnetic shield structure of each embodiment demonstrated the example applied to the torque detection apparatus 10, it is not restricted to this, Even in what detects a change of magnetism, such as a rotation angle detection apparatus which detects the rotation angle of a motor Applicable. In this case, the detection target does not have to be a rotating shaft, and may be, for example, a member that detects a current value, and the magnetic shield member 26 has a shape having a halfway angle such as a triangle or a square as a whole. It may be done.

  DESCRIPTION OF SYMBOLS 10 ... Torque detection apparatus (sensor apparatus), 11 ... Housing, 13 ... Unit accommodating part, 20 ... Sensor unit (detection part), 26 ... Magnetic shield member, 27 ... 1st magnetic shield piece, 28 ... 2nd magnetic shield piece 29 ... third magnetic shield piece (other magnetic shield piece), 27a, 28a, 29a ... end (end of magnetic shield piece), 29b ... space, X ... arc of sensor unit, Y ... diameter of sensor unit Clearance in the direction, Z: clearance in the circumferential direction of the sensor unit.

Claims (6)

A housing provided with a detection unit for detecting a change in magnetism in a detection target; and a magnetic shield member provided on an outer periphery of the detection unit and made of a material having a different thermal expansion coefficient from the housing. In the magnetic shield structure in which the magnetic shield member is integrated,
The magnetic shield member has a plurality of magnetic shield pieces having ends on both sides in the circumferential direction,
The magnetic shield structure, wherein the plurality of magnetic shield pieces are arranged in a state of being arranged along a circumferential direction of an outer periphery of the detection unit.   2. The end portions of the plurality of magnetic shield pieces facing each other between adjacent magnetic shield pieces are provided in a state of overlapping and abutting in a direction approaching or separating from the detection unit. Magnetic shield structure as described in 1.   Each end part which opposes between adjacent magnetic shield pieces among these magnetic shield pieces is provided in the state which overlapped and spaced apart in the direction which adjoins or leaves | separates with respect to the said detection part. The magnetic shield structure described.   Among the plurality of magnetic shield pieces, each of the end portions facing each other between adjacent magnetic shield pieces has a gap not larger than a size capable of shielding magnetism from other than the detection target in the circumferential direction of the outer periphery of the detection unit. The magnetic shield structure according to claim 1, wherein the magnetic shield structures are arranged side by side. Among the plurality of magnetic shield pieces, a space surrounded by other magnetic shield pieces is provided between the opposing end portions between adjacent magnetic shield pieces,
The respective end portions facing each other between the adjacent magnetic shield pieces are provided in a state of being inserted into the space so as to be movable along the circumferential direction of the outer periphery of the detection unit. Magnetic shield structure. The magnetic shield structure according to any one of claims 1 to 5,
The sensor apparatus which detects the change of the magnetism which arises when the rotating shaft made into the said detection object rotates by the said detection part.

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