Torque sensor

Abstract

In the torque sensor (1), the sleeve (21) is an annular member mounted on the first rotating member. The intermediate member (26) is an annular member disposed on the outer peripheral surface of the sleeve (21). The magnet (25) is an annular member disposed on the outer peripheral surface of the intermediate member (26). The yoke (35) is mounted on the second rotating member and faces the magnet (25) in the radial direction. The rotating member connecting portion (211) of the sleeve (21) is cylindrical and contacts the first rotating member. The intermediate member connecting portion (215) is located at a position axially offset from the rotating member connecting portion (211) in a direction parallel to the central axis Z. The outer diameter (E219) of the sleeve end portion (219), which is the end portion of the intermediate member connecting portion (215) on the side opposite to the side where the rotating member connecting portion (211) is located, is smaller than the minimum inner diameter (I25) of the magnet (25).

Description

Technical Field

[0001] The present invention relates to a torque sensor. Background Art

[0002] An electric power steering device mounted on a vehicle includes a torque sensor for detecting a steering torque. The torque sensor changes its output in accordance with the relative rotation of an input shaft and an output shaft that are connected together by a torsion bar. An ECU (Electronic Control Unit) controls a motor based on information obtained from the torque sensor, and the torque generated by the motor assists the steering. For example, an example of a torque sensor is described in Patent Document 1. In the torque sensor of Patent Document 1, a magnet is mounted on a steering shaft by means of a sleeve. The sleeve has a small-diameter portion that is press-fitted into the steering shaft and a large-diameter portion that fixes the magnet with an adhesive. Thus, when the sleeve is press-fitted into the steering shaft, deformation of the large-diameter portion that holds the magnet can be suppressed. As a result, the distance between the magnet and the yoke is not likely to deviate from the design value, and a decrease in the detection accuracy of the torque sensor can be suppressed.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2019 / 059230 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In addition, the sleeve that supports the magnet in Patent Document 1 preferably has a small-diameter portion and a large-diameter portion and is small in the radial direction. However, if the step between the small-diameter portion and the large-diameter portion is reduced, the step between the small-diameter portion and the large-diameter portion cannot be pressed when the sleeve is press-fitted into the steering shaft. Although it is possible to press the top end portion of the large-diameter portion instead of the step, stress may be generated in the magnet when the top end of the large-diameter portion is pressed. If stress is generated in the magnet, the magnetic characteristics of the magnet will change, and thus it may be possible to manufacture a magnet that does not meet the factory standards. Therefore, the yield rate in the manufacture of the steering device is reduced.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a torque sensor that can suppress a decrease in detection accuracy and can suppress stress generation in a magnet when fixed to a rotating member.

[0009] Solutions for Solving the Problems

[0010] To achieve the above object, a torque sensor according to one aspect of the present invention includes: an annular sleeve mounted on a first rotating member; an annular intermediate member disposed on an outer peripheral surface of the sleeve; an annular magnet disposed on an outer peripheral surface of the intermediate member; and a yoke mounted on a second rotating member that rotates relative to the first rotating member and faces the magnet in a direction orthogonal to a central axis of the sleeve, i.e., in a radial direction. The sleeve includes: a rotating member connecting portion that is cylindrical and in contact with the first rotating member; and an intermediate member connecting portion that is cylindrical and located at a position offset in an axial direction parallel to the central axis with respect to the rotating member connecting portion. An outer diameter of an end portion of the intermediate member connecting portion on a side opposite to a side where the rotating member connecting portion is located, i.e., an outer diameter of a sleeve end portion, is smaller than a minimum inner diameter of the magnet.

[0011] By bringing the rotating member connecting portion into contact with the first rotating member, deformation of the intermediate member connecting portion that holds the magnet can be suppressed when the sleeve is pressed into the first rotating member. Therefore, the distance between the magnet and the yoke is not likely to deviate from a design value. Accordingly, the torque sensor can suppress a reduction in detection accuracy. Moreover, when the sleeve is pressed into the first rotating member, even if the sleeve end portion is pressed, stress is not easily generated in the magnet. Therefore, the torque sensor of the present invention can suppress a reduction in detection accuracy and can suppress a situation where stress is generated in the magnet when fixed to the rotating member.

[0012] As a desired aspect of the torque sensor, an outer diameter of the intermediate member connecting portion is larger than an outer diameter of the rotating member connecting portion.

[0013] Thereby, stress generated in the rotating member connecting portion in the process of pressing the sleeve into the input shaft is absorbed by deformation of an enlarged portion located between the rotating member connecting portion and the intermediate member connecting portion. Therefore, transmission of stress generated in the sleeve pressing process to the intermediate member connecting portion can be suppressed.

[0014] As a desired aspect of the torque sensor, an outer diameter of the intermediate member connecting portion is smaller than an outer diameter of the rotating member connecting portion.

[0015] Thereby, compared with the case where the outer diameter of the intermediate member connecting portion is larger than the outer diameter of the rotating member connecting portion, the magnet can be disposed at a more radially inner position. Therefore, miniaturization of the torque sensor can be achieved.

[0016] As a desired aspect of the torque sensor, an outer diameter of the intermediate member connecting portion is the same as an outer diameter of the rotating member connecting portion.

[0017] Thus, compared with the case where the outer diameter of the connecting portion of the intermediate member is larger than the outer diameter of the connecting portion of the rotating member, the magnet can be disposed at a position closer to the inner side in the radial direction. Therefore, miniaturization of the torque sensor can be achieved. In addition, the shape of the sleeve becomes simple, so that the manufacturing process of the sleeve can be simplified.

[0018] As a desired technical solution of the torque sensor, the outer diameter of the end portion of the sleeve is larger than the inner diameter of the end portion of the intermediate member on the side opposite to the side where the rotating member connecting portion is located, that is, the end portion of the intermediate member, and smaller than the outer diameter of the end portion of the intermediate member.

[0019] Thus, the end portion of the sleeve prevents the intermediate member from moving, so that the possibility of position deviation of the intermediate member is reduced. Therefore, the torque sensor of the present invention can further reduce the possibility of a decrease in detection accuracy.

[0020] As a desired technical solution of the torque sensor, the intermediate member is disposed at a gap in the axial direction with respect to the end portion of the sleeve.

[0021] Thus, when the sleeve is pressed into the first rotating member, even if the end portion of the sleeve is pressed, it is not easy to cause deformation in the intermediate member. As a result, stress is less likely to occur in the magnet in contact with the intermediate member. Therefore, the torque sensor of the present invention can further suppress the stress generated in the magnet when fixed to the rotating member.

[0022] As a desired technical solution of the torque sensor, the outer diameter of the end portion of the sleeve is equal to or less than the inner diameter of the end portion of the intermediate member on the side opposite to the side where the rotating member connecting portion is located, that is, the end portion of the intermediate member.

[0023] Thus, when the sleeve is pressed into the first rotating member, even if the end portion of the sleeve is pressed, it is not easy to cause deformation in the intermediate member. As a result, stress is less likely to occur in the magnet in contact with the intermediate member. Therefore, the magnet assembly of the present invention can further suppress the stress generated in the magnet when fixed to the rotating member.

[0024] Effects of the Invention

[0025] The torque sensor of the present invention can suppress a decrease in detection accuracy and can suppress stress generation in the magnet when fixed to the rotating member. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic view of the steering device of the present embodiment.

[0027] Figure 2 is a perspective view of the steering device of the present embodiment.

[0028] Figure 3It is an exploded perspective view of the steering device of the present embodiment.

[0029] Figure 4 It is a cross-sectional view of the steering device of the present embodiment.

[0030] Figure 5 It is Figure 4 a partial enlarged view of.

[0031] Figure 6 It is taken Figure 4 by cutting the steering device of the present embodiment with a plane different from that and is a cross-sectional view obtained.

[0032] Figure 7 It is Figure 6 a partial enlarged view of.

[0033] Figure 8 It is a cross-sectional view of the periphery of the magnet assembly of the present embodiment.

[0034] Figure 9 It is Figure 8 a partial enlarged view of.

[0035] Figure 10 It is an exploded perspective view showing the magnet assembly, yoke, etc. of the present embodiment.

[0036] Figure 11 It is an exploded perspective view of the magnet assembly of the present embodiment.

[0037] Figure 12 It is a schematic diagram showing the manufacturing method (plastic deformation process of the outer peripheral surface) of the magnet assembly of the present embodiment.

[0038] Figure 13 It is a schematic diagram showing the manufacturing method (first mold configuration process) of the magnet assembly of the present embodiment.

[0039] Figure 14 It is a schematic diagram showing the manufacturing method (intermediate member filling process) of the magnet assembly of the present embodiment.

[0040] Figure 15 It is a schematic diagram showing the manufacturing method (first mold removal process) of the magnet assembly of the present embodiment.

[0041] Figure 16 It is a schematic diagram showing the manufacturing method (second mold configuration process) of the magnet assembly of the present embodiment.

[0042] Figure 17 It is a schematic diagram showing the manufacturing method (magnet filling process) of the magnet assembly of the present embodiment.

[0043] Figure 18It is a schematic diagram showing the manufacturing method (second mold removal process) of the magnet assembly of the present embodiment.

[0044] Figure 19 It is a cross-sectional view of the periphery of the magnet assembly of the first modified example.

[0045] Figure 20 It is a cross-sectional view of the periphery of the magnet assembly of the second modified example. Detailed implementation manners

[0046] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In addition, the following manners for implementing the invention (hereinafter referred to as embodiments) do not limit the present invention. Further, the constituent elements of the following embodiments include elements that can be easily conceived by those skilled in the art, elements that are substantially the same, and elements within the so-called equivalent range. In addition, the constituent elements disclosed in the following embodiments can be appropriately combined.

[0047] (Embodiment)

[0048] Figure 1 It is a schematic diagram of the steering device of the present embodiment. Figure 2 It is a perspective view of the steering device of the present embodiment. Figure 3 It is an exploded perspective view of the steering device of the present embodiment. Figure 4 It is a cross-sectional view of the steering device of the present embodiment.

[0049] As Figure 1 shown, the steering device 80 sequentially includes a steering wheel 81, a steering shaft 82, a steering force assist mechanism 83, a universal joint 84, an intermediate shaft 85, and a universal joint 86 in the order of the force transmitted from the operator, and the steering device 80 is engaged with a pinion shaft 87. In the following description, the front of the vehicle equipped with the steering device 80 is simply referred to as the front, and the rear of the vehicle is simply referred to as the rear. As Figure 2 shown, the steering force assist mechanism 83 is provided near the steering wheel 81 and is disposed in the passenger compartment separated from the outside. As Figure 3 shown, the steering device 80 includes a gearbox 920, an intermediate plate 10, and a steering column housing 820. The gearbox 920 is mounted on the vehicle, and the steering column housing 820 is fixed to the gearbox 920 with the intermediate plate 10 interposed therebetween.

[0050] As Figure 1 and Figure 4 shown, the steering shaft 82 includes an input shaft 82a, an output shaft 82b, and a torsion bar 82c. The input shaft 82a is supported by a bearing on Figure 4The steering column housing 820 shown. The input shaft 82a is rotatable relative to the steering column housing 820. One end of the input shaft 82a is connected to the steering wheel 81. The other end of the input shaft 82a is connected to the torsion bar 82c. The torsion bar 82c is fitted into a hole provided at the center of the input shaft 82a and fixed to the input shaft 82a by a pin.

[0051] As Figure 4 shown, the output shaft 82b is supported by the intermediate plate 10 via the bearing 71 and supported by the gearbox 920 via the bearing 72. For example, the bearing 71 is pressed into the intermediate plate 10 and the bearing 72 is pressed into the gearbox 920. The output shaft 82b is rotatable relative to the intermediate plate 10 and the gearbox 920. One end of the output shaft 82b is connected to the torsion bar 82c. The other end of the output shaft 82b is connected to the universal joint 84. The torsion bar 82c is fixed to the output shaft 82b by being pressed into a hole provided at the center of the output shaft 82b.

[0052] In addition, the front end portion of the input shaft 82a is located inside the output shaft 82b. A convex portion provided on one of the outer peripheral surface of the input shaft 82a and the inner peripheral surface of the output shaft 82b is fitted into a concave portion provided on the other. Thereby, even when the torsion bar 82c no longer functions as a connecting member, torque can be transmitted between the input shaft 82a and the output shaft 82b.

[0053] As Figure 1 shown, the intermediate shaft 85 connects the universal joint 84 and the universal joint 86. One end portion of the intermediate shaft 85 is connected to the universal joint 84 and the other end portion is connected to the universal joint 86. One end portion of the pinion shaft 87 is connected to the universal joint 86 and the other end portion of the pinion shaft 87 is connected to the steering gear 88. The universal joints 84 and 86 are, for example, cardan joints. The rotation of the steering shaft 82 is transmitted to the pinion shaft 87 via the intermediate shaft 85. That is, the intermediate shaft 85 rotates together with the steering shaft 82.

[0054] As Figure 1 shown, the steering gear 88 includes a pinion 88a and a rack 88b. The pinion 88a is connected to the pinion shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into a linear motion using the rack 88b. The rack 88b is connected to the tie rod 89. The angle of the wheel is changed by moving the rack 88b.

[0055] As Figure 1 shown, the steering force assist mechanism 83 includes a reduction gear 92 and an electric motor 93. The reduction gear 92 is, for example, a worm reduction gear, as Figure 3 and Figure 4As shown, it includes a gearbox 920, a worm gear 921, and a worm 922. The torque generated by the electric motor 93 is transmitted to the worm gear 921 by means of the worm 922, causing the worm gear 921 to rotate. The worm 922 and the worm gear 921 increase the torque generated by the electric motor 93. The worm gear 921 is fixed to the output shaft 82b. For example, the worm gear 921 is press-fitted onto the output shaft 82b. Therefore, the reduction gear 92 applies an auxiliary steering torque to the output shaft 82b. The steering device 80 is an electric power steering device with a steering column assist type.

[0056] As Figure 1 shown, the steering device 80 includes an ECU (Electronic Control Unit) 90, a torque sensor 1, and a vehicle speed sensor 95. The electric motor 93, the torque sensor 1, and the vehicle speed sensor 95 are electrically connected to the ECU 90. The torque sensor 1 outputs the steering torque transmitted to the input shaft 82a to the ECU 90 through CAN (Controller Area Network) communication. The vehicle speed sensor 95 detects the traveling speed (vehicle speed) of the vehicle body equipped with the steering device 80. The vehicle speed sensor 95 is provided on the vehicle body and outputs the vehicle speed to the ECU 90 through CAN communication.

[0057] The ECU 90 controls the operation of the electric motor 93. The ECU 90 obtains signals from the torque sensor 1 and the vehicle speed sensor 95 respectively. In a state where the ignition switch 98 is turned on, power is supplied from the power supply device 99 (such as an in-vehicle battery) to the ECU 90. The ECU 90 calculates an auxiliary steering command value based on the steering torque and the vehicle speed. The ECU 90 adjusts the power value supplied to the electric motor 93 based on the auxiliary steering command value. The ECU 90 obtains information on the induced voltage of the electric motor 93 or information output from a resolver or the like provided in the electric motor 93. The ECU 90 reduces the force required for the operation of the steering wheel 81 by controlling the electric motor 93.

[0058] Figure 5 is Figure 4 a partial enlarged view of. Figure 6 is in a plane different from Figure 4 a cross-sectional view obtained by cutting the steering device of this embodiment. Figure 7 is Figure 6 a partial enlarged view of. Figure 8 is a cross-sectional view of the periphery of the magnet assembly of this embodiment. Figure 9 is Figure 8 a partial enlarged view of. Figure 10 is an exploded perspective view showing the magnet assembly and the yoke etc. of this embodiment. Figure 11 is an exploded perspective view of the magnet assembly of this embodiment.

[0059] As Figure 4 shown, the torque sensor 1 is disposed between the steering column housing 820 and the gearbox 920. More specifically, the torque sensor 1 is located in the space sandwiched by the steering column housing 820 and the intermediate plate 10. As Figures 4 to 7 shown, the torque sensor 1 includes a magnet assembly 20, a sleeve 31 (second sleeve), a holding portion 32, a yoke 35, a sensor housing 40, a magnetic flux collecting member 46, a printed circuit board 43, a Hall IC 47, a first cover 48, and a second cover 49. As Figure 8 shown, the magnet assembly 20 includes a sleeve 21 (first sleeve), an intermediate member 26, and a magnet 25.

[0060] The sleeve 21 is a non-magnetic metal. Specific examples of the non-magnetic metal include austenitic stainless steel (SUS304). As Figure 5 shown, the sleeve 21 is a cylindrical member and is mounted on the input shaft 82a. The sleeve 21 is formed, for example, by deep drawing. The sleeve 21 includes a rotating member connecting portion 211, an intermediate member connecting portion 215, and an enlarged portion 213. In the following description, the direction parallel to the central axis Z of the sleeve 21 is referred to as the axial direction. The direction parallel to a straight line orthogonal to the central axis Z and passing through the central axis Z is referred to as the radial direction. The direction along the circumference centered on the central axis Z is referred to as the circumferential direction. The central axis Z is the same straight line as the rotation axis of the input shaft 82a.

[0061] As Figure 8 shown, the rotating member connecting portion 211 is a cylindrical member and is press-fitted onto the outer peripheral surface of the input shaft 82a. The rear end face of the rotating member connecting portion 211 faces the end face 823a of the raised portion 822a of the input shaft 82a. A ring-shaped groove 821a is provided in a portion of the input shaft 82a corresponding to the rear end of the rotating member connecting portion 211. The intermediate member connecting portion 215 is a cylindrical member. The outer diameter of the intermediate member connecting portion 215 is larger than the outer diameter of the rotating member connecting portion 211. The intermediate member connecting portion 215 is located at a position axially offset from the rotating member connecting portion 211. The intermediate member connecting portion 215 is located in front of the rotating member connecting portion 211. The enlarged portion 213 connects the rotating member connecting portion 211 and the intermediate member connecting portion 215. The outer diameter of the enlarged portion 213 increases from the rotating member connecting portion 211 toward the intermediate member connecting portion 215.

[0062] The rotation member connection portion 211 and the intermediate member connection portion 215 are connected by the enlarged portion 213, so that the rotation member connection portion 211 and the intermediate member connection portion 215 can be arranged at positions separated axially and also at positions separated radially. By configuring the sleeve 21 in this way, the stress generated in the rotation member connection portion 211 during the process of pressing the sleeve 21 onto the input shaft 82a is absorbed by the deformation of the enlarged portion 213, so that the stress generated during the pressing process of the sleeve 21 can be prevented from being transmitted to the intermediate member connection portion 215.

[0063] A magnet 25 is arranged at the intermediate member connection portion 215 with the aid of the intermediate member 26, so that the stress generated during the pressing process can be prevented from being transmitted to the magnet 25 via the intermediate member connection portion 215 and the intermediate member 26. By preventing the stress from acting on the magnet 25, it is possible to prevent the deterioration of the sensor output characteristics associated with the demagnetization of the magnet 25.

[0064] As Figure 8 shown, the intermediate member connection portion 215 includes a plurality of concave portions 216, a plurality of convex portions 217, and a sleeve end portion 219. The concave portions 216 are provided on the outer peripheral surface of the intermediate member connection portion 215. The convex portions 217 are provided on the inner peripheral surface of the intermediate member connection portion 215. The convex portions 217 are provided on the back side of the concave portions 216. The concave portions 216 and the convex portions 217 are formed integrally by stamping, for example. That is, the outer peripheral surface of the intermediate member connection portion 215 is plastically deformed radially inward to form the concave portions 216 and the convex portions 217. The convex portions 217 are arranged at positions radially outside the inner peripheral surface of the rotation member connection portion 211. That is, the inner diameter I217 of the convex portion 217 is larger than the inner diameter I211 of the rotation member connection portion 211. The number of the concave portions 216 and the number of the convex portions 217 are both even numbers. As Figure 11 shown, the even number of concave portions 216 and the even number of convex portions 217 are arranged at equal intervals in the circumferential direction. Therefore, with respect to a set of the concave portions 216 and the convex portions 217, another set of the concave portions 216 and the convex portions 217 is provided on the opposite side across the central axis Z. The sleeve end portion 219 is the end portion of the intermediate member connection portion 215 on the side (front side) opposite to the side where the rotation member connection portion 211 is located. The sleeve end portion 219 extends radially outward.

[0065] As Figure 8 shown, the intermediate member 26 is arranged on the outer peripheral surface of the intermediate member connection portion 215. The intermediate member 26 is formed in a ring shape. The intermediate member 26 is made of resin. Specific examples of the resin include polyphenylene sulfide (PPS: Poly Phenylene Sulfide) and polyamide 12 (PA12).

[0066] The intermediate member 26 includes a thin-walled portion 261, a plurality of thick-walled portions 263, and an intermediate member end portion 269. The wall thickness of the thick-walled portion 263 is larger than that of the thin-walled portion 261. The wall thickness refers to the radial thickness, which will be used in the same sense in the following description. In the present embodiment, as Figure 11 shown, the thin-walled portion 261 is formed in a ring shape, and an even number of thick-walled portions 263 are arranged at equal intervals in the circumferential direction. As Figure 8 shown, in a cross section including the central axis Z, the thick-walled portion 263 is axially located between a partial portion of the thin-walled portion 261 and another partial portion of the thin-walled portion 261. The thick-walled portion 263 is clamped by the thin-walled portion 261 from both sides in the axial direction. In other words, in a cross section including the central axis Z, the wall thickness of the intermediate member 26 is not constant but varies according to the axial position. The inner circumferential surfaces of the thin-walled portion 261 and the thick-walled portion 263 are in contact with the outer circumferential surface of the intermediate member connecting portion 215. The radially inner end portion of the thick-walled portion 263 is located in the concave portion 216 of the intermediate member connecting portion 215.

[0067] The intermediate member end portion 269 is the end portion (front side) of the intermediate member 26 on the side opposite to the side where the rotating member connecting portion 211 is located. When viewed axially, a partial portion of the intermediate member end portion 269 overlaps with the sleeve end portion 219. The outer diameter E219 of the sleeve end portion 219 is larger than the inner diameter I269 of the intermediate member end portion 269 and smaller than the outer diameter E269 of the intermediate member end portion 269. As Figure 9 shown, the intermediate member end portion 269 is arranged with a gap C in the axial direction with respect to the sleeve end portion 219. In addition, in Figure 9 the gap C is exaggeratedly depicted, and the size of the illustrated gap C may also be different from the actual size.

[0068] As Figure 8 shown, the magnet 25 is arranged on the outer circumferential surface of the intermediate member 26. The magnet 25 is formed in a ring shape. In the ring-shaped magnet 25, the S pole and the N pole are alternately arranged in the circumferential direction. The magnet 25 can be said to be mounted on the sleeve 21 by means of the intermediate member 26. Therefore, the magnet 25 rotates together with the input shaft 82a and the sleeve 21. The magnet 25 faces the yoke 35 with a radial gap therebetween. The radial interval L1 between the magnet 25 and the yoke 35 is smaller than the wall thickness difference L2 between the thin-walled portion 261 and the thick-walled portion 263. The wall thickness difference L2 can also be referred to as the step between the thin-walled portion 261 and the thick-walled portion 263.

[0069] The magnet 25 contains magnet powder as a hard magnetic material and resin. The material obtained by mixing the magnet powder and the resin is cured to form the magnet 25. The magnet 25 is called a bonded magnet. Specific examples of the hard magnetic material include ferrite or neodymium. Specific examples of the resin include polyphenylene sulfide (PPS) and polyamide 12 (PA12). In the present embodiment, the linear expansion coefficient of the intermediate member 26 is smaller than the linear expansion coefficient of the resin of the magnet. In addition, the resin used for the magnet 25 may be the same as the resin used for the intermediate member 26.

[0070] As Figure 8 shown, the magnet 25 includes a mounting portion 251 and a tapered portion 253. The mounting portion 251 is the part that contacts the intermediate member 26. The wall thickness of the mounting portion 251 is constant. The tapered portion 253 is disposed behind the mounting portion 251. The tapered portion 253 faces the rotating member connecting portion 211 in the radial direction. The wall thickness of the tapered portion 253 becomes smaller toward one end (rear) in the axial direction. The wall thickness of the tapered portion 253 becomes smaller as it moves away from the mounting portion 251. More specifically, the outer diameter of the tapered portion 253 is constant, and only the inner diameter of the tapered portion 253 becomes larger as it moves away from the mounting portion 251. For example, the length of the tapered portion 253 in the axial direction is more than 1 / 4 and less than 1 / 2 of the length of the magnet 25 as a whole in the axial direction. When viewed from the axial direction, the magnet 25 does not overlap with the sleeve end portion 219. The outer diameter E219 of the sleeve end portion 219 is smaller than the minimum inner diameter I25 of the magnet 25.

[0071] The sleeve 31 is a non-magnetic body and is a metal. Specific examples of the non-magnetic metal include austenitic stainless steel (SUS304). As Figure 5 shown, the sleeve 31 is a cylindrical member and is mounted on the output shaft 82b. Specifically, the sleeve 31 is press-fitted onto the outer peripheral surface of the output shaft 82b. The front end surface of the sleeve 31 does not contact the output shaft 82b. That is, an axial gap is provided between the front end surface of the sleeve 31 and the output shaft 82b. The axial position of the rear end surface of the sleeve 31 is the same as the axial position of the rear end surface of the output shaft 82b. The position of the sleeve 31 is determined by aligning the rear end surface of the sleeve 31 with the rear end surface of the output shaft 82b.

[0072] The holding portion 32 is a non-magnetic body. For example, the holding portion 32 is a resin. Specific examples of the resin include polybutylene terephthalate (PBT) or polyoxymethylene resin (POM). The holding portion 32 is a cylindrical member and is mounted on the output shaft 82b by means of the sleeve 31. As [[ID=7 shown, the holding portion 32 includes a small-diameter portion 321, a large-diameter portion 322, and a protrusion 327. As ​As shown, the holding portion 32 is integrally formed with the sleeve 31 by injection molding. The small-diameter portion 321 is a cylindrical member and contacts the outer peripheral surface of the sleeve 31. The large-diameter portion 322 is a cylindrical member. The outer diameter of the large-diameter portion 322 is larger than the outer diameter of the small-diameter portion 321. The large-diameter portion 322 is located behind the small-diameter portion 321. The front end of the large-diameter portion 322 is connected to the rear end of the small-diameter portion 321. The protrusion 327 protrudes rearward from the rear end surface of the small-diameter portion 321 and faces the magnet 25. There is a gap between the protrusion 327 and the magnet 25.

[0073] As ​ shown, the yoke 35 includes a first yoke 351 and a second yoke 352. The first yoke 351 and the second yoke 352 are soft magnetic materials. As a specific example of the soft magnetic material, a nickel-iron alloy is cited. The first yoke 351 and the second yoke 352 are fixed to the holding portion 32. The first yoke 351 and the second yoke 352 rotate together with the output shaft 82b, the sleeve 31, and the holding portion 32. The first yoke 351 includes a first annular portion 351a and a plurality of first tooth portions 351b. The first annular portion 351a is a plate orthogonal to the axial direction. The first tooth portions 351b protrude forward from the first annular portion 351a. The plurality of first tooth portions 351b are arranged at equal intervals in the circumferential direction. The second yoke 352 includes a second annular portion 352a and a plurality of second tooth portions 352b. The second annular portion 352a is a plate parallel to the first annular portion 351a and is located in front of the first annular portion 351a. The second tooth portions 352b protrude rearward from the second annular portion 352a. The plurality of second tooth portions 352b are arranged at equal intervals in the circumferential direction. One second tooth portion 352b is located between two first tooth portions 351b. That is, the first tooth portions 351b and the second tooth portions 352b are arranged alternately in the circumferential direction. The first tooth portions 351b and the second tooth portions 352b face the magnet 25.

[0074] The sensor housing 40 is a non-magnetic material. For example, the sensor housing 40 is resin. As a specific example of the resin, it is polybutylene terephthalate (PBT) or polyamide 66. As ​ shown, a bushing 403 is disposed in the hole 401 of the sensor housing 40. For example, the bushing 403 is, for example, aluminum alloy and is integrally formed with the sensor housing 40. The sensor housing 40 is fixed to the intermediate plate 10 by bolts passing through the bushing 403.

[0075] As ​ shown, the magnetic flux concentrating member 46 includes a first magnetic flux concentrating member 461 and a second magnetic flux concentrating member 462. The first magnetic flux concentrating member 461 and the second magnetic flux concentrating member 462 are soft magnetic materials, for example, nickel-iron alloys. The first magnetic flux concentrating member 461 and the second magnetic flux concentrating member 462 are fixed to the sensor housing 40. As ​As shown, the first flux concentrating member 461 faces the first annular portion 351a. There is a gap between the first flux concentrating member 461 and the first annular portion 351a. The first flux concentrating member 461 is magnetized corresponding to the magnetization of the first yoke 351. The second flux concentrating member 462 faces the second annular portion 352a. There is a gap between the second flux concentrating member 462 and the second annular portion 352a. The second flux concentrating member 462 is magnetized corresponding to the magnetization of the second yoke 352.

[0076] The torque sensor 1 is basically designed based on a sufficient safety factor, but the magnet 25 and the sleeve 21 may be axially displaced relative to the input shaft 82a due to vibrations or impacts applied to the torque sensor 1, etc. Alternatively, there is a possibility that the yoke 35 and the sleeve 31 and the holding portion 32 are axially displaced relative to the output shaft 82b. In the torque sensor 1 of the present embodiment, even when the sleeve 21 moves relative to the input shaft 82a, by bringing the magnet 25 into contact with the holding portion 32, it is easy to make the displacement of the magnet 25 below the allowable value. In addition, even when the sleeve 31 and the holding portion 32 move relative to the output shaft 82b, by bringing the holding portion 32 into contact with the magnet 25, it is easy to make the displacement of the yoke 35 below the allowable value. In this way, the torque sensor 1 has robustness. Therefore, the torque sensor 1 can suppress a decrease in detection accuracy.

[0077] The printed circuit board 43 is fixed to the sensor housing 40. The Hall IC 47 is mounted on the printed circuit board 43. The Hall IC 47 is disposed between the first flux concentrating member 461 and the second flux concentrating member 462. There are gaps between the Hall IC 47 and the first flux concentrating member 461 and between the Hall IC 47 and the second flux concentrating member 462. The output signal of the Hall IC 47 changes corresponding to the change in the magnetic flux density between the Hall IC 47 and the first flux concentrating member 461 and the second flux concentrating member 462. The Hall IC 47 outputs the signal to the ECU 90.

[0078] When the steering wheel 81 is operated, torque is transmitted to the input shaft 82a. Since the output shaft 82b is connected to the input shaft 82a by means of a torsion bar 82c, the input shaft 82a rotates relative to the output shaft 82b. Therefore, the magnet 25 rotates relative to the first tooth portion 351b and the second tooth portion 352b. As a result, the intensity of the magnetization of each of the first yoke 351 and the second yoke 352 changes. Therefore, the magnetic flux density between the first flux concentrating member 461 and the second flux concentrating member 462 changes. The Hall IC 47 detects this change in magnetic flux density. The ECU 90 controls the electric motor 93 using the steering torque calculated based on the output signal of the Hall IC 47.

[0079] The first cover 48 is a non-magnetic material. For example, the first cover 48 is a resin. Specific examples of the resin include polybutylene terephthalate (PBT) or polyamide 66. As ​ shown, the first cover 48 is installed at the rear end of the sensor housing 40. The first cover 48 covers the printed circuit board 43.

[0080] The second cover 49 is a non-magnetic material. For example, the second cover 49 is a resin. Specific examples of the resin include polybutylene terephthalate (PBT) or polyamide 66. As ​ shown, the second cover 49 is installed at the front end of the sensor housing 40. As ​ shown, the second cover 49 includes an annular main body portion 491 and a plurality of claw portions 492. The plurality of claw portions 492 are arranged at equal intervals in the circumferential direction. The claw portions 492 project forward from the main body portion 491. The plurality of claw portions 492 are inserted into the intermediate plate 10 by press-fitting, and the claw portions 492 are brought into contact with the inner peripheral surface of the intermediate plate 10. Thereby, the center of the sensor housing 40 as viewed from the axial direction is easily aligned with the center of the intermediate plate 10.

[0081] ​ is a schematic diagram showing a manufacturing method of the magnet assembly of the present embodiment. The manufacturing method of the magnet assembly 20 of the present embodiment includes a sleeve processing step, a first mold configuration step, an intermediate member forming step, a second mold configuration step, and a magnet forming step.

[0082] In the sleeve processing step, as ​ shown, the outer peripheral surface of the intermediate member connecting portion 215 is plastically deformed in the radial direction. For example, the outer peripheral surface of the intermediate member connecting portion 215 is plastically deformed inward in the radial direction by stamping, thereby forming a concave portion 216 and a convex portion 217.

[0083] After the sleeve processing step, the first mold configuration step is performed. In the first mold configuration step, as ​ shown, the first mold 51 is disposed outside the intermediate member connecting portion 215. The first mold 51 is a hollow mold formed of metal. The first mold 51 includes an introduction flow path for introducing resin and a discharge flow path for discharging resin. The first mold 51 can be divided into two parts along a plane including the central axis Z. As ​ indicated by the arrow of, the divided first mold 51 is mounted on the intermediate member connecting portion 215 from both sides.

[0084] After the first mold configuration step, the intermediate member forming step is performed. In the intermediate member forming step, as ​As shown, resin is filled in the first mold 51. Injection molding is used in the intermediate member forming step. That is, the nozzle of the cylinder containing the molten resin is disposed in the introduction flow path of the first mold 51. The molten resin is extruded from the cylinder and made to enter the first mold 51. The excess molten resin is discharged from the discharge flow path of the first mold 51. After the molten resin in the first mold 51 cools, as ​ shown, the first mold 51 is removed. Thus, the intermediate member 26 including the thin wall portion 261 and the thick wall portion 263 is formed.

[0085] After the intermediate member forming step, the second mold disposition step is performed. In the second mold disposition step, as ​ shown, the second mold 52 is disposed outside the intermediate member 26. The second mold 52 is a hollow mold formed of metal. The second mold 52 includes an introduction flow path for introducing resin and a discharge flow path for discharging resin. The second mold 52 can be divided into two parts along a plane orthogonal to the central axis Z. As ​ indicated by the arrow of, the divided second mold 52 is mounted on the intermediate member 26 from both sides.

[0086] After the second mold disposition step, the magnet forming step is performed. In the magnet forming step, as ​ shown, resin is filled in the second mold 52. Injection molding is used in the magnet forming step. That is, the nozzle of the cylinder containing the molten resin is disposed in the introduction flow path of the second mold 52. The molten resin is extruded from the cylinder and made to enter the second mold 52. The excess molten resin is discharged from the discharge flow path of the second mold 52. After the molten resin in the second mold 52 cools, as ​ shown, the second mold 52 is removed. Thus, the magnet 25 including the mounting portion 251 and the tapered portion 253 is formed.

[0087] In addition, the sleeve 21 is not necessarily mounted on the input shaft 82a. For example, it may also be that the sleeve 21 and the magnet 25 are mounted on the output shaft 82b, and the sleeve 31 and the yoke 35 are mounted on the input shaft 82a. When the sleeve 21 is mounted on the output shaft 82b, the sleeve 21 is press-fitted onto the outer peripheral surface of the output shaft 82b.

[0088] The intermediate member connection portion 215 of the sleeve 21 does not necessarily include the concave portion 216 and the convex portion 217. The intermediate member connection portion 215 only needs to include a portion for hooking the thick wall portion 263. For example, it may also be that the intermediate member connection portion 215 has a through hole, and the thick wall portion 263 enters the through hole. The outer diameter of the intermediate member connection portion 215 is not necessarily larger than the outer diameter of the rotating member connection portion 211. The outer diameter of the intermediate member connection portion 215 may be smaller than the outer diameter of the rotating member connection portion 211, or may be the same as the outer diameter of the rotating member connection portion 211.

[0089] As described above, the torque sensor 1 of the present embodiment includes a sleeve 21, an intermediate member 26, a magnet 25, and a yoke 35. The sleeve 21 is an annular member mounted on the first rotating member (input shaft 82a). The intermediate member 26 is an annular member disposed on the outer peripheral surface of the sleeve 21. The magnet 25 is an annular member disposed on the outer peripheral surface of the intermediate member 26. The yoke 35 is mounted on the second rotating member (output shaft 82b) that rotates relative to the first rotating member, and faces the magnet 25 in the radial direction, which is a direction orthogonal to the central axis Z of the sleeve 21. The sleeve 21 includes a rotating member connecting portion 211 and an intermediate member connecting portion 215. The rotating member connecting portion 211 is cylindrical and contacts the first rotating member. The intermediate member connecting portion 215 is cylindrical and is located at a position offset in the axial direction parallel to the central axis Z with respect to the rotating member connecting portion 211. The intermediate member 26 includes a thin wall portion 261 and a thick wall portion 263 having a wall thickness larger than that of the thin wall portion 261. The inner peripheral surface of the thin wall portion 261 and the inner peripheral surface of the thick wall portion 263 contact the intermediate member connecting portion 215.

[0090] By bringing the rotating member connecting portion 211 into contact with the first rotating member (input shaft 82a), deformation of the intermediate member connecting portion 215 that holds the magnet 25 can be suppressed when the sleeve 21 is pressed into the first rotating member. Therefore, the distance between the magnet 25 and the yoke 35 (the first tooth portion 351b and the second tooth portion 352b) is not likely to deviate from the design value. Therefore, the torque sensor 1 can suppress a decrease in detection accuracy. Further, in the above-mentioned Patent Document 1, the magnet is mounted on the sleeve by an adhesive, so when manufacturing the sensor, it is necessary to mount the magnet on the sleeve after aligning the magnet with the sleeve, which causes a problem of complicated manufacturing processes. In contrast, in the torque sensor 1 of the present embodiment, the intermediate member 26 includes a thin wall portion 261 and a thick wall portion 263. Thus, the thick wall portion 263 is hooked on the outer peripheral surface of the sleeve 21. Relative movement of the intermediate member 26 and the sleeve 21 in the axial and circumferential directions is suppressed. Further, when manufacturing the torque sensor 1 of the present embodiment in the above-mentioned manner, after forming the intermediate member 26 on the outer periphery of the sleeve 21, the magnet 25 is formed on the outer periphery of the intermediate member 26. Therefore, it is not necessary to position the magnet 25 relative to the sleeve 21, and thus the manufacturing process can be simplified.

[0091] In the torque sensor 1 of the present embodiment, the outer diameter of the intermediate member connecting portion 215 is larger than the outer diameter of the rotating member connecting portion 211.

[0092] Accordingly, in the process of pressing the sleeve 21 onto the input shaft 82a, the stress generated at the rotating member connecting portion 211 is absorbed by the deformation of the enlarged portion 213 located between the rotating member connecting portion 211 and the intermediate member connecting portion 215. Therefore, the transmission of the stress generated in the pressing process of the sleeve 21 to the intermediate member connecting portion 215 can be suppressed.

[0093] In the torque sensor 1 of the present embodiment, it is also possible that the outer diameter of the intermediate member connecting portion 215 is smaller than the outer diameter of the rotating member connecting portion 211.

[0094] Accordingly, compared with the case where the outer diameter of the intermediate member connecting portion 215 is larger than the outer diameter of the rotating member connecting portion 211, the magnet 25 can be arranged at a more radially inner position. Therefore, miniaturization of the torque sensor 1 can be achieved.

[0095] It is also possible that the outer diameter of the intermediate member connecting portion 215 is the same as the outer diameter of the rotating member connecting portion 211.

[0096] Accordingly, compared with the case where the outer diameter of the intermediate member connecting portion 215 is larger than the outer diameter of the rotating member connecting portion 211, the magnet 25 can be arranged at a more radially inner position. Therefore, miniaturization of the torque sensor 1 can be achieved. In addition, the shape of the sleeve 21 becomes simple, so the manufacturing process of the sleeve 21 can be simplified.

[0097] In the torque sensor 1 of the present embodiment, the magnet 25 includes a tapered portion 253 whose wall thickness becomes smaller toward one end in the axial direction. The tapered portion 253 faces the rotating member connecting portion 211 in the radial direction.

[0098] In order to reduce the stress acting on the magnet 25 when the rotating member connecting portion 211 is pressed onto the first rotating member (input shaft 82a), a radial gap is provided between the magnet 25 and the small-diameter portion. In order to form this gap, it is necessary to make the mold (second mold 52) enter this gap when forming the magnet 25. In the torque sensor 1 of the present embodiment, by making the magnet 25 include the tapered portion 253, it is easy to remove the used mold when forming the magnet 25.

[0099] In the torque sensor 1 of the present embodiment, the intermediate member 26 includes an even number of thick-walled portions 263. The even number of thick-walled portions 263 are arranged at equal intervals in the circumferential direction.

[0100] The concave portions of the sleeve 21 corresponding to the thick-walled portions 263 are formed, for example, by stamping. Since the even number of concave portions are arranged at equal intervals in the circumferential direction, it is easy to perform stamping on the sleeve 21. In addition, forming the concave portions by stamping is preferable when the sleeve 21 is in the shape of a thin-walled cylinder. By making the sleeve shape thin-walled, the weight reduction of the torque sensor 1 can be achieved.

[0101] In the torque sensor 1 of the present embodiment, in a cross section including the central axis Z, the thick wall portion 263 is axially located between a partial portion of the thin wall portion 261 and another partial portion of the thin wall portion 261.

[0102] Assuming that the thick wall portion 263 is disposed at the axial end of the intermediate member 26, in order to use the thick wall portion 263 to prevent the movement of the intermediate member 26 relative to the sleeve 21, it is necessary to provide the thick wall portion 263 at both ends of the intermediate member 26. That is, it is necessary to arrange the thick wall portion 263 in two rows. In contrast, in the torque sensor 1 of the present embodiment, as long as the thick wall portion 263 has at least one, it can prevent the movement of the intermediate member 26 relative to the sleeve 21. The torque sensor 1 of the present embodiment can reduce the number of required thick wall portions 263.

[0103] In the torque sensor 1 of the present embodiment, the intermediate member connecting portion 215 includes a recess 216 provided on the outer peripheral surface and a protrusion 217 provided on the back side of the recess 216.

[0104] Thereby, the recess 216 and the protrusion 217 can be easily formed by stamping. The torque sensor 1 of the present embodiment can easily perform the process of forming a portion for hooking the thick wall portion 263 on the sleeve 21.

[0105] In the torque sensor 1 of the present embodiment, the protrusion 217 is disposed at a position radially outside the inner peripheral surface of the rotating member connecting portion 211.

[0106] Thereby, when the sleeve 21 is pressed into the first rotating member (input shaft 82a), the protrusion 217 does not contact the first rotating member. Therefore, no force is directly applied from the first rotating member to the intermediate member connecting portion 215. The torque sensor 1 of the present embodiment can reduce the stress generated in the intermediate member 26 and the magnet 25.

[0107] In the torque sensor 1 of the present embodiment, the radial interval L1 between the magnet 25 and the yoke 35 is smaller than the wall thickness difference L2 between the thin wall portion 261 and the thick wall portion 263.

[0108] Thereby, assuming that even when the magnet 25 generates an abnormality and the magnet 25 moves in the direction close to the yoke 35, the state where the thick wall portion 263 is hooked on the sleeve 21 can be maintained. Therefore, the magnet 25 does not fall off from the sleeve 21. The torque sensor 1 of the present embodiment can reduce the possibility of being in a state where no signal is output.

[0109] In the torque sensor 1 of the present embodiment, the intermediate member 26 is resin. The magnet 25 contains magnet powder and resin. The linear expansion coefficient of the intermediate member 26 is smaller than the linear expansion coefficient of the resin of the magnet 25.

[0110] Accordingly, even when the intermediate member 26 and the magnet 25 are exposed to an environment with temperature variations, the torque sensor 1 of the present embodiment can reduce the stress generated in the intermediate member 26 and the magnet 25.

[0111] In the torque sensor 1 of the present embodiment, the intermediate member 26 is resin. The magnet 25 contains magnet powder and resin. The resin of the intermediate member 26 and the resin of the magnet 25 are the same material.

[0112] Accordingly, even when the intermediate member 26 and the magnet 25 are exposed to an environment with temperature variations, the torque sensor 1 of the present embodiment can reduce the stress generated in the intermediate member 26 and the magnet 25.

[0113] The manufacturing method of the magnet assembly 20 of the present embodiment includes a first mold arrangement step, an intermediate member formation step, a second mold arrangement step, and a magnet formation step. The first mold arrangement step is a process of arranging the first mold 51 outside the intermediate member connection portion 215. The intermediate member formation step is a process of forming the intermediate member 26 including the thin wall portion 261 and the thick wall portion 263 having a wall thickness larger than that of the thin wall portion 261 by filling resin in the first mold 51. The second mold arrangement step is a process of arranging the second mold 52 outside the intermediate member 26. The magnet formation step is a process of forming the magnet 25 by filling resin containing magnet powder in the second mold 52.

[0114] Accordingly, the resin-containing intermediate member 26 and the magnet 25 can be firmly attached to each other. Therefore, relative movement of the intermediate member 26 and the magnet 25 in the axial direction and the circumferential direction is suppressed. In addition, the intermediate member 26 includes the thin wall portion 261 and the thick wall portion 263. Accordingly, the thick wall portion 263 is hooked on the outer peripheral surface of the sleeve 21. Relative movement of the intermediate member 26 and the sleeve 21 in the axial direction and the circumferential direction is suppressed. Therefore, the possibility of position deviation of the magnet 25 can be reduced. Therefore, the manufacturing method of the magnet assembly 20 of the present embodiment can further suppress a decrease in detection accuracy.

[0115] The manufacturing method of the magnet assembly 20 of the present embodiment includes a sleeve processing step of plastically deforming the outer peripheral surface of the intermediate member connection portion 215 in the radial direction, which is a direction orthogonal to the central axis Z, before the first mold arrangement step.

[0116] Accordingly, the manufacturing method of the magnet assembly 20 of the present embodiment can easily form a portion for the thick wall portion 263 to hook on the sleeve 21, for example, by stamping.

[0117] In the manufacturing method of the magnet assembly 20 of the present embodiment, injection molding is used in the intermediate member formation step and the magnet formation step.

[0118] Therefore, the manufacturing method of the magnet assembly 20 of the present embodiment can more easily form the intermediate member 26 and the magnet 25.

[0119] In addition, the torque sensor 1 of the present embodiment includes a sleeve 21, an intermediate member 26, a magnet 25, and a yoke 35. The sleeve 21 is an annular member mounted on the first rotating member (input shaft 82a). The intermediate member 26 is an annular member disposed on the outer peripheral surface of the sleeve 21. The magnet 25 is an annular member disposed on the outer peripheral surface of the intermediate member 26. The yoke 35 is mounted on the second rotating member (output shaft 82b) that rotates relative to the first rotating member, and faces the magnet 25 in the radial direction, which is orthogonal to the central axis Z of the sleeve 21. The sleeve 21 includes a rotating member connecting portion 211 and an intermediate member connecting portion 215. The rotating member connecting portion 211 is cylindrical and contacts the first rotating member. The intermediate member connecting portion 215 is cylindrical and is located at a position offset in the axial direction parallel to the central axis Z with respect to the rotating member connecting portion 211. The outer diameter E219 of the end portion of the intermediate member connecting portion 215 on the side opposite to the side where the rotating member connecting portion 211 is located, that is, the sleeve end portion 219, is smaller than the minimum inner diameter I25 of the magnet 25.

[0120] By bringing the rotating member connecting portion 211 into contact with the first rotating member (input shaft 82a), deformation of the intermediate member connecting portion 215 that holds the magnet 25 can be suppressed when the sleeve 21 is pressed into the first rotating member. Therefore, the distance between the magnet 25 and the yoke 35 (the first tooth portion 351b and the second tooth portion 352b) is not likely to deviate from the design value. Therefore, the torque sensor 1 can suppress a decrease in detection accuracy. In addition, the sleeve that supports the magnet in Patent Document 1 preferably has a small-diameter portion and a large-diameter portion and is small in the radial direction. However, if the step between the small-diameter portion and the large-diameter portion is reduced, the step between the small-diameter portion and the large-diameter portion cannot be pressed when the sleeve is pressed into the steering shaft. Although the top end portion of the large-diameter portion can be pressed instead of the step, stress may be generated in the magnet when the top end of the large-diameter portion is pressed. If stress is generated in the magnet, the magnetic characteristics of the magnet will change, so it may be impossible to manufacture a magnet that meets the factory standards. Therefore, the yield rate in the manufacture of the steering device will decrease. In contrast, in the torque sensor 1 of the present embodiment, the outer diameter E219 of the sleeve end portion 219 is smaller than the minimum inner diameter I25 of the magnet 25. Therefore, when the sleeve 21 is pressed into the first rotating member, stress is not likely to be generated in the magnet 25 even if the sleeve end portion 219 is pressed. Therefore, the torque sensor 1 of the present embodiment can suppress a decrease in detection accuracy and can suppress the generation of stress in the magnet 25 when fixed to the rotating member.

[0121] In the torque sensor 1 of the present embodiment, the outer diameter E219 of the sleeve end portion 219 is larger than the inner diameter I269 of the end portion of the intermediate member 26 on the side opposite to the side where the rotating member connecting portion 211 is located, that is, the intermediate member end portion 269, and smaller than the outer diameter E269 of the intermediate member end portion 269.

[0122] Thereby, the sleeve end portion 219 prevents the intermediate member 26 from moving, and thus the possibility of the occurrence of the positional deviation of the intermediate member 26 can be reduced. Therefore, the torque sensor 1 of the present embodiment can further reduce the possibility of the occurrence of the reduction in the detection accuracy.

[0123] In the torque sensor 1 of the present embodiment, the intermediate member 26 is arranged with a gap C in the axial direction with respect to the sleeve end portion 219.

[0124] Thereby, when the sleeve 21 is pressed into the first rotating member, even if the sleeve end portion 219 is pressed, it is not easy to cause deformation in the intermediate member 26. As a result, stress is less likely to occur in the magnet 25 in contact with the intermediate member 26. Therefore, the torque sensor 1 of the present embodiment can further suppress the stress generated in the magnet 25 when it is fixed to the rotating member.

[0125] (First modification example)

[0126] ​ It is a cross-sectional view of the periphery of the magnet assembly of the first modification example. In addition, the same reference numerals are given to the constituent elements that are the same as those described in the above embodiment, and the repeated description is omitted.

[0127] As ​ shown, the magnet assembly 20A of the first modification example includes a sleeve 21A and an intermediate member 26A. The sleeve 21A includes an intermediate member connecting portion 215A. The intermediate member connecting portion 215A includes a plurality of convex portions 216A, a plurality of concave portions 217A, and a sleeve end portion 219A. The convex portions 216A are provided on the outer peripheral surface of the intermediate member connecting portion 215A. The concave portions 217A are provided on the inner peripheral surface of the intermediate member connecting portion 215A. The concave portions 217A are provided on the back side of the convex portions 216A. The convex portions 216A and the concave portions 217A are formed at one time by, for example, stamping. That is, by plastically deforming the outer peripheral surface of the intermediate member connecting portion 215A toward the outside in the radial direction, the convex portions 216A and the concave portions 217A are formed. The plurality of convex portions 216A and the plurality of concave portions 217A are arranged at equal intervals in the circumferential direction. The sleeve end portion 219A is the end portion of the intermediate member connecting portion 215A on the side opposite to the side where the rotating member connecting portion 211 is located (front side). The sleeve end portion 219A extends toward the outside in the radial direction.

[0128] The intermediate member 26A includes a thick-walled portion 265, a plurality of thin-walled portions 267, and an end portion 269A of the intermediate member. The wall thickness of the thin-walled portion 267 is smaller than the wall thickness of the thick-walled portion 265. The thick-walled portion 265 is formed in a ring shape, and an even number of thin-walled portions 267 are arranged at equal intervals in the circumferential direction. In a cross section including the central axis Z, the thin-walled portion 267 is axially located between a partial portion of the thick-walled portion 265 and another partial portion of the thick-walled portion 265. The thin-walled portion 267 is sandwiched by the thick-walled portion 265 from both sides in the axial direction. In other words, in a cross section including the central axis Z, the wall thickness of the intermediate member 26A is not constant but varies according to the axial position. The inner circumferential surfaces of the thick-walled portion 265 and the thin-walled portion 267 are in contact with the outer circumferential surface of the intermediate member connecting portion 215A. In addition, the radial interval L1 between the magnet 25 and the yoke 35 is smaller than the wall thickness difference L3 between the thin-walled portion 261 and the thick-walled portion 263.

[0129] The end portion 269A of the intermediate member is the end portion (front side) of the intermediate member 26A on the side opposite to the side where the rotating member connecting portion 211 is located. When viewed axially, a partial portion of the end portion 269A of the intermediate member overlaps with the end portion 219A of the sleeve. The outer diameter E219A of the end portion 219A of the sleeve is larger than the inner diameter I269A of the end portion 269A of the intermediate member and smaller than the outer diameter E269A of the end portion 269A of the intermediate member. Similar to ​ the relationship between the end portion 269 of the intermediate member and the end portion 219 of the sleeve shown, the end portion 269A of the intermediate member is arranged with a gap in the axial direction with respect to the end portion 219A of the sleeve.

[0130] As described above, in the first modification, the intermediate member 26 includes an even number of thin-walled portions 267. When viewed axially, the even number of thin-walled portions 267 are arranged at equal intervals in the circumferential direction, that is, in the direction along the circumference centered on the central axis Z.

[0131] The convex portions of the sleeve 21A corresponding to the thin-walled portions 267 are formed, for example, by stamping. Since the even number of convex portions are arranged at equal intervals in the circumferential direction, it is easy to perform stamping on the sleeve 21. In addition, forming the convex portions by stamping is preferable when the sleeve 21A is a thin-walled cylindrical shape. By thinning the sleeve shape, the weight reduction of the torque sensor 1 can be achieved.

[0132] (Second Modification)

[0133] ​ is a cross-sectional view of the periphery of the magnet assembly of the second modification. In addition, the same reference numerals are given to the constituent elements identical to those described in the above embodiment, and the repeated description is omitted.

[0134] As ​As shown, the magnet assembly 20B of the second modification includes a sleeve 21B. The sleeve 21B includes an intermediate member connecting portion 215B. The intermediate member connecting portion 215B includes a sleeve end portion 219B. The sleeve end portion 219B is the end portion of the intermediate member connecting portion 215B on the side (front side) opposite to the side where the rotating member connecting portion 211 is located. The sleeve end portion 219B extends toward the outer side in the radial direction.

[0135] When viewed axially, the intermediate member end portion 269 does not overlap with the sleeve end portion 219B. The outer diameter E219B of the sleeve end portion 219B is equal to or less than the inner diameter I269 of the intermediate member end portion 269. For example, in the second modification, the outer diameter E219B of the sleeve end portion 219B is equal to the inner diameter I269 of the intermediate member end portion 269. The sleeve end portion 219B protrudes axially (forward) with respect to the plane passing through the end faces of the intermediate member 26 and the magnet 25.

[0136] As described above, in the second modification, the outer diameter E219B of the sleeve end portion 219B is equal to or less than the inner diameter I269 of the intermediate member end portion 269, which is the end portion of the intermediate member 26 on the side opposite to the side where the rotating member connecting portion 211 is located.

[0137] Accordingly, when the sleeve 21B is pressed into the first rotating member, even if the sleeve end portion 219B is pressed, it is not easy for the intermediate member 26 to be deformed. As a result, it is even less likely for stress to occur in the magnet 25 in contact with the intermediate member 26. Therefore, the magnet assembly 20B of the second modification can further suppress the stress generated in the magnet 25 when it is fixed to the rotating member.

[0138] ​

[0139] 1. Torque sensor; 10. Intermediate plate; 20, 20A, 20B, Magnet assembly; 21, 21A, 21B, Sleeve; 25, Magnet; 26, 26A, Intermediate member; 31, Sleeve; 32, Holding portion; 35, Yoke; 40, Sensor housing; 43, Printed circuit board; 46, Magnetic flux concentrating member; 47, Hall IC; 71, 72, Bearing; 80, Steering device; 81, Steering wheel; 82, Steering shaft; 82a, Input shaft; 82b, Output shaft; 82c, Torsion bar; 83, Steering force assist mechanism; 84, Universal joint; 85, Intermediate shaft; 86, Universal joint; 87, Pinion shaft; 88, Steering gear; 88a, Pinion; 88b, Rack; 89, Tie rod; 90, ECU; 92, Reduction gear; 93, Electric motor; 95, Vehicle speed sensor; 98, Ignition switch; 99, Power supply device; 211, Rotating member connecting portion; 213, Enlarged portion; 215, 215A, 215B, Intermediate member connecting portion; 216, Concave portion; 216A, Convex portion; 217, Convex portion; 217A, Concave portion; 219, 219A, 219B, Sleeve end; 251, Mounting portion; 253, Tapered portion; 261, Thin wall portion; 263, Thick wall portion; 265, Thick wall portion; 267, Thin wall portion; 269, 269A, Intermediate member end; 321, Small diameter portion; 322, Large diameter portion; 327, Projection; 920, Gear box; 921, Worm gear; 922, Worm; C, Clearance; L1, Spacing; L2, L3, Wall thickness difference; Z, Central axis.

Claims

1. A torque sensor, wherein, The torque sensor includes: a ring-shaped sleeve mounted on the first rotating member; a ring-shaped intermediate member disposed on the outer peripheral surface of the sleeve; a ring-shaped magnet disposed on the outer peripheral surface of the intermediate member; and a yoke mounted on a second rotating member that rotates relative to the first rotating member and facing the magnet in a direction orthogonal to the central axis of the sleeve, i.e., in the radial direction, The sleeve includes: a rotating member connecting portion that is cylindrical and in contact with the first rotating member; and an intermediate member connecting portion that is cylindrical and located at a position axially offset from the rotating member connecting portion in a direction parallel to the central axis, the outer diameter of the end portion of the sleeve on the side opposite to the side where the rotating member connecting portion is located, i.e., the outer diameter of the sleeve end portion, is smaller than the minimum inner diameter of the magnet, the intermediate member is mounted on the outer peripheral surface of the intermediate member connecting portion of the sleeve, the intermediate member includes: a thin wall portion; and a thick wall portion having a wall thickness larger than the wall thickness in the radial direction of the thin wall portion, in a cross section including the central axis, the thick wall portion is axially located between a partial portion of the thin wall portion and another partial portion of the thin wall portion, the radially inner end portion of the thick wall portion is located in a concave portion of the intermediate member connecting portion, the radial interval between the magnet and the yoke is smaller than the wall thickness difference between the thin wall portion and the thick wall portion.

2. The torque sensor according to claim 1, wherein the outer diameter of the intermediate member connecting portion is larger than the outer diameter of the rotating member connecting portion.

3. The torque sensor according to claim 1, wherein the outer diameter of the intermediate member connecting portion is smaller than the outer diameter of the rotating member connecting portion.

4. The torque sensor according to claim 1, wherein the outer diameter of the intermediate member connecting portion is the same as the outer diameter of the rotating member connecting portion.

5. The torque sensor according to any one of claims 1 to 4, wherein the outer diameter of the sleeve end portion is larger than the inner diameter of the end portion of the intermediate member on the side opposite to the side where the rotating member connecting portion is located, i.e., the inner diameter of the intermediate member end portion, and smaller than the outer diameter of the intermediate member end portion.

6. The torque sensor according to any one of claims 1 to 4, wherein the intermediate member is disposed with a gap in the axial direction relative to the sleeve end portion.

7. The torque sensor according to claim 5, wherein the intermediate member is disposed with a gap in the axial direction relative to the sleeve end portion.

8. The torque sensor according to any one of claims 1 to 4, wherein the outer diameter of the sleeve end portion is less than or equal to the inner diameter of the end portion of the intermediate member on the side opposite to the side where the rotating member connecting portion is located, i.e., the inner diameter of the intermediate member end portion.

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