Torque sensor

Abstract

A torque sensor 10 comprises: a housing 20; and a magnetic-field concentrating yoke assembly 40 that is disposed in the inside of the housing 20 and is detachably attached to the housing 20. The housing 20 has a storage section 26 for storing the magnetic-field concentrating yoke assembly 40. The magnetic-field concentrating yoke assembly 40 is furnished with: a sealing-member situating part 44 enabling an O-ring 70, being a sealing member, to be situated thereon; and a protruding section 45 stored in the inside of the storage section 26. The protruding section 45 has, on its outer peripheral surface 46, a plurality of crush ribs 47 that abut on a storage-section inner wall 27, being the inner wall of the storage section 26. Provided between the sealing-member situating part 44 and the protruding section 45 is an inclined connection section 48 that is inclined with respect to the insertion direction of the protruding section 45 and that connects the sealing-member situating part 44 and the protruding section 45. The crush ribs 47 abut on the storage-section inner wall 27 at a length shorter than a length in which the protruding section 45 and the inclined connection section 48 are combined in the direction of insertion of the protruding section 45 into the storage section 26.

Description

Torque Sensor

[0001] The present disclosure relates to a torque sensor.

[0002] One example of a torque sensor that detects torque applied to a rotating body of a steering device is one that detects torque by detecting changes in magnetism. For example, a magnetic detection module described in Patent Document 1 includes a multi-pole magnet fixed to an input shaft, a set of yokes fixed to an output shaft, a magnetic flux induction member that induces magnetic flux in a magnetic circuit to a magnetic sensor, and a magnetic sensor that detects the magnetic flux induced by the magnetic flux induction member and converts it into a voltage signal.

[0003] Patent document 1 also describes an embodiment in which a sensor portion that houses a magnetic sensor is provided so as to protrude from the tip surface of the tubular portion, and the magnetic detection module is attached to the housing by inserting the tubular portion into an attachment hole in the housing, and describes that an O-ring used as a sealing material is interposed between the attachment hole in the housing and the tubular portion inserted into the attachment hole.

[0004] Japanese Patent Application Laid-Open No. 2020-8547

[0005] In Patent Document 1, the magnetic detection module has a case assembly and a cap, and if an O-ring is not used, the case assembly is attached to the housing by itself, and if an O-ring is used, the cap is attached to the case assembly, and the O-ring is attached to the cap, and then the magnetic detection module is attached to the housing. That is, in Patent Document 1, in the case of a non-waterproof specification, the magnetic detection module is attached to the housing by itself as a case assembly, and in the case of a waterproof specification, the case assembly is attached to the housing via a cap on which an O-ring is attached. However, in a configuration in which the case assembly is attached to the housing via a cap on which an O-ring is attached, the number of parts increases in order to achieve both waterproof and non-waterproof specifications, which tends to increase manufacturing costs.

[0006] The present disclosure has been made in view of the above, and aims to provide a torque sensor that can be made compatible with both waterproof and non-waterproof specifications while suppressing increases in manufacturing costs.

[0007] The torque sensor of the present disclosure comprises a housing and a magnetism collecting yoke assembly that is disposed inside the housing and is detachably attached to the housing, the housing having a storage section that stores the magnetism collecting yoke assembly, the magnetism collecting yoke assembly having a seal member arrangement section in which a seal member can be arranged, and a protrusion that is stored inside the storage section, the protrusion having a plurality of crush ribs on its outer surface that abut against an inner wall of the storage section, which is the inner wall of the storage section, the protrusion having a step relative to the seal member arrangement section because its outline shape when viewed in the direction of insertion of the protrusion into the storage section is smaller than the outline shape of the seal member arrangement section, and an inclined connection section is provided between the seal member arrangement section and the protrusion that is inclined with respect to the insertion direction and connects the seal member arrangement section and the protrusion, the end of the crush rib on the side where the seal member arrangement section is located in the insertion direction is connected to the inclined connection section, and the crush rib abuts against the inner wall of the storage section at a length that is shorter than the combined length of the protrusion and the inclined connection section in the insertion direction.

[0008] According to this configuration, the magnetic flux collecting yoke assembly is provided with a seal member arrangement portion in which a seal member can be arranged. Therefore, when using the torque sensor in a waterproof specification, the seal member can be arranged in the seal member arrangement portion and the protrusion can be stored in the storage portion of the housing, thereby ensuring a seal between the magnetic flux collecting yoke assembly and the housing. Furthermore, when using the torque sensor in a non-waterproof specification, the seal member can be stored in the storage portion without arranging a seal member in the seal member arrangement portion, thereby allowing a magnetic flux collecting yoke assembly of the same shape as the magnetic flux collecting yoke assembly used in the waterproof specification to be used in the non-waterproof specification. As a result, it is possible to achieve both waterproof and non-waterproof specifications while suppressing increases in manufacturing costs.

[0009] Furthermore, with this configuration, the protrusion of the magnetic flux collecting yoke assembly has multiple crush ribs on its outer circumferential surface that abut against the inner wall of the storage compartment of the housing, which is the inner wall of the storage compartment. Therefore, the protrusion can be stored in the storage compartment while being positioned relative to the storage compartment. Furthermore, because the abutment length of the crush ribs against the inner wall of the storage compartment is shorter than the combined length of the protrusion and the inclined connection portion, the crush ribs can abut against the inner wall of the storage compartment while suppressing deformation of the protrusion due to the crush ribs abutting against the inner wall of the storage compartment. This allows the O-ring disposed as a sealing member in the sealing member disposition portion of the magnetic flux collecting yoke assembly to be crushed uniformly, thereby ensuring uniform sealing performance by the O-ring around the entire circumference. As a result, the sealing performance of the O-ring can be improved.

[0010] In a preferred embodiment, the length of the crush rib from the position of the seal member arrangement portion in the insertion direction to the end on the opposite side to the side on which the seal member arrangement portion is located is shorter than the combined length of the protrusion and the inclined connection portion in the insertion direction.

[0011] According to this configuration, the length of the crush rib from the position of the seal member placement portion in the insertion direction of the protrusion into the housing storage portion to the end opposite the side where the seal member placement portion is located is shorter than the combined length of the protrusion and the inclined connection portion in the same direction, so the abutment length of the crush rib against the storage portion inner wall can be made shorter than the combined length of the protrusion and the inclined connection portion. This allows the crush rib to abut against the storage portion inner wall while suppressing deformation of the protrusion due to the crush rib abutting against the storage portion inner wall, and can uniformly crush the O-ring placed in the seal member placement portion of the magnetic flux collecting yoke assembly. As a result, the sealing performance of the O-ring can be improved.

[0012] A desirable form has a magnet attached to one of two shafts connected via a torsion bar and a stator attached to the other shaft, and the crush ribs are arranged on the outer peripheral surface on both sides of the protrusion in the axial direction of the shaft.

[0013] With this configuration, the crush ribs are located on the outer peripheral surface on both sides of the protruding portion in the axial direction of the shaft, so the position of the magnetic flux collecting yoke assembly relative to the housing can be accurately determined in the same direction. As a result, variation in the magnetic flux detected by the magnetic flux collecting yoke assembly when detecting steering torque can be reduced, allowing steering torque to be detected appropriately.

[0014] A desirable form has a magnet attached to one of two shafts connected via a torsion bar and a stator attached to the other shaft, and the crush ribs are arranged on the outer peripheral surface on both sides of the protrusion in a direction perpendicular to both the axial direction of the shaft and the insertion direction.

[0015] With this configuration, the crush ribs are disposed on the outer peripheral surface of both sides of the protrusion in a direction perpendicular to both the axial direction of the shaft and the insertion direction, so that the position of the magnetic flux collecting yoke assembly relative to the housing can be accurately determined in the same direction. As a result, variation in the magnetic flux detected by the magnetic flux collecting yoke assembly when detecting steering torque can be reduced, enabling steering torque to be detected appropriately.

[0016] In a preferred embodiment, the inner wall of the storage section has a tapered section in which the distance between the inner wall of the storage section and the outer peripheral surface of the protrusion decreases as the wall moves from the opening side of the storage section toward the rear in the insertion direction, and a flat section that is located further rear than the tapered section in the insertion direction and in which the distance between the inner wall of the storage section and the outer peripheral surface of the protrusion is constant, and the crush rib abuts against the inner wall of the storage section at the flat section.

[0017] According to this configuration, the crush ribs abut against the flat portions of the inner wall of the storage compartment at a position away from the seal member placement portion. Therefore, even if the protrusions are deformed when the crush ribs abut against the inner wall of the storage compartment, the deformation of the protrusions is less likely to affect the seal member placement portion. Therefore, deformation of the seal member placement portion caused by deformation of the protrusions due to the crush ribs abutting against the inner wall of the storage compartment can be more reliably suppressed, and the O-ring placed in the seal member placement portion of the magnetic flux collecting yoke assembly can be crushed more uniformly. As a result, the sealing performance of the O-ring can be improved.

[0018] In a preferred embodiment, the inner wall of the storage section has an expanded diameter section located on the opening side of the storage section in the insertion direction and spaced apart from the outer peripheral surface of the protrusion, and a reduced diameter section located further back than the expanded diameter section in the insertion direction and whose distance from the outer peripheral surface of the protrusion is smaller than the distance between the expanded diameter section and the outer peripheral surface of the protrusion, and the crush rib abuts the inner wall of the storage section at the reduced diameter section.

[0019] According to this configuration, the crush ribs abut against the reduced-diameter portion of the inner wall of the storage compartment at a position away from the seal member placement portion. Therefore, even if the protrusion is deformed by the crush ribs abutting against the inner wall of the storage compartment, the deformation of the protrusion is less likely to affect the seal member placement portion, and deformation of the seal member placement portion due to the deformation of the protrusion can be more reliably suppressed. This allows the O-ring placed in the seal member placement portion of the magnetic flux collecting yoke assembly to be crushed evenly. As a result, the sealing performance of the O-ring can be improved.

[0020] In a preferred embodiment, the housing has a seal member abutment portion where the seal member abuts against the inner surface, located closer to the entrance than the storage portion in the insertion direction, and the seal member is arranged in the seal member arrangement portion and abuts against both the seal member arrangement portion and the seal member abutment portion at a position closer to the entrance than the storage portion in the insertion direction.

[0021] According to this configuration, the O-ring is disposed in the seal member arrangement portion of the magnetic flux collecting yoke assembly and abuts against both the seal member abutment portion of the housing and the seal member arrangement portion of the magnetic flux collecting yoke assembly at a position closer to the entrance of the storage portion in the direction of insertion of the protrusion into the storage portion. This allows the O-ring to prevent liquids such as water from entering from the outside of the housing toward the inside of the storage portion. As a result, the sealing properties of the O-ring can be effectively utilized, improving the waterproofness of the torque sensor.

[0022] The torque sensor according to the present disclosure has the advantage of being able to achieve both waterproof and non-waterproof specifications while suppressing increases in manufacturing costs.

[0023] FIG. 1 is a schematic diagram illustrating a steering device according to a first embodiment. FIG. 2 is a cross-sectional view of a main portion of the stub shaft and the first pinion gear, including a portion where a torque sensor is disposed. FIG. 3 is a cross-sectional view of a main portion of a torque sensor included in the steering device according to the first embodiment. FIG. 4 is a schematic diagram illustrating an overview of a magnet, a stator, and a magnetic flux collecting yoke included in the torque sensor. FIG. 5 is a cross-sectional view of the housing shown in FIG. 3. FIG. 6 is a plan view of a magnetic flux collecting yoke assembly as viewed in the direction of arrows A-A in FIG. 3. FIG. 7 is a schematic diagram illustrating a state in which a protruding portion of the magnetic flux collecting yoke assembly is stored in a storage portion of the housing. FIG. 8 is a cross-sectional view of FIG. 7 along arrows B-B. FIG. 9 is an exploded perspective view of a stub shaft, a first pinion gear, and a torque sensor. FIG. 10 is a schematic diagram of a magnetic flux collecting yoke assembly and a storage portion when the torque sensor is used in a non-waterproof configuration. FIG. 11 is a cross-sectional view of a housing included in a torque sensor according to a second embodiment. Fig. 12 is a plan view of a magnetic flux collecting yoke assembly of a torque sensor according to a second embodiment. Fig. 13 is a schematic diagram showing a state in which a protruding portion of the magnetic flux collecting yoke assembly is stored in a storage portion of a housing according to the second embodiment. Fig. 14 is a schematic diagram showing a modified example of the torque sensor according to the second embodiment, in which the inner wall of the storage portion has an expanded diameter portion and a reduced diameter portion.

[0024] The present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to the following modes for carrying out the invention (hereinafter referred to as embodiments). Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

[0025] [First Embodiment] Fig. 1 is a schematic diagram for explaining a steering device 80 of the first embodiment. As shown in Fig. 1, the steering device 80 includes, in the order in which a force applied by an operator is transmitted, a steering wheel 81, a steering shaft 82, a universal joint 84, an intermediate shaft 85, a universal joint 86, a stub shaft 87, a steering gear 88, and a tie rod 89. The steering device 80 also includes a control device (hereinafter referred to as an ECU (Electronic Control Unit)) 100, a torque sensor 10, and an electric motor 102. A vehicle speed sensor 101 is provided in the vehicle and outputs a vehicle speed signal V to the ECU 100 via CAN (Controller Area Network) communication.

[0026] The steering shaft 82 is connected to the steering wheel 81 at one end and to a universal joint 84 at the other end.

[0027] Intermediate shaft 85 is connected at one end to universal joint 84 and at the other end to universal joint 86. Stub shaft 87 is connected at one end to universal joint 86 and at the other end to torque sensor 10. Torque sensor 10 is connected at one end to stub shaft 87 and at the other end to a first pinion gear 88a of steering gear 88.

[0028] More specifically, the first pinion gear 88a is a shaft-shaped member having a gear (not shown) that meshes with a rack bar 88b (described later) formed on the end opposite to the side connected to the stub shaft 87, and the stub shaft 87 and the first pinion gear 88a are connected via a torsion bar 87a (see FIG. 2). One end of the torsion bar 87a is connected to the stub shaft 87, and the other end is connected to the first pinion gear 88a, and the torsion bar 87a transmits rotational torque between the stub shaft 87 and the first pinion gear 88a.

[0029] Torque sensor 10 is a torque detection device that detects torque acting on a shaft connected to torque sensor 10, and detects rotational torque transmitted between stub shaft 87 and first pinion gear 88a via torsion bar 87a. In other words, stub shaft 87 and first pinion gear 88a, which are connected via torsion bar 87a, are shafts that are the detection target when torque is detected by torque sensor 10.

[0030] The steering gear 88 includes a first pinion gear 88a, a rack bar 88b, and a second pinion gear 88c. The first pinion gear 88a is connected to the stub shaft 87 via a torsion bar 87a. Rack teeth (not shown) formed on the rack bar 88b mesh with the gear of the first pinion gear 88a. The rack bar 88b also meshes with the second pinion gear 88c at a position different from that of the first pinion gear 88a.

[0031] An electric motor 102 is connected to the second pinion gear 88c via a worm reduction gear (not shown), and the second pinion gear 88c is rotatable by driving force transmitted from the electric motor 102. The electric motor 102 rotates the second pinion gear 88c via a worm reduction gear (not shown). The electric motor 102 is, for example, a brushless motor, but may also be a motor including brushes (sliders) and a commutator (commutator).

[0032] The steering gear 88 converts the rotational motion transmitted to the first pinion gear 88a and the second pinion gear 88c into linear motion using a rack bar 88b disposed inside a rack housing (not shown). The steering device 80 according to the first embodiment is a dual pinion assist type in which the rack bar 88b performs linear motion using the rotational motion transmitted from the first pinion gear 88a and the second pinion gear 88c. The tie rod 89 is connected to the rack bar 88b. In other words, the steering device 80 is a rack-and-pinion type electric power steering device.

[0033] The torque sensor 10 detects, as steering torque, the steering force of the driver transmitted to the steering shaft 82 via the steering wheel 81. The vehicle speed sensor 101 detects the traveling speed (vehicle speed) of the vehicle on which the steering device 80 is mounted. The electric motor 102, the torque sensor 10, and the vehicle speed sensor 101 are electrically connected to the ECU 100.

[0034] The ECU 100 controls the operation of the electric motor 102. The ECU 100 also acquires signals from the torque sensor 10 and the vehicle speed sensor 101. That is, the ECU 100 acquires the steering torque T from the torque sensor 10 and the vehicle speed signal V from the vehicle speed sensor 101. When the ignition switch 103 is on, the ECU 100 is supplied with power from a power supply device (e.g., an on-board battery) 104. The ECU 100 calculates an assist steering command value of the assist command based on the steering torque T and the vehicle speed signal V. The ECU 100 then adjusts the power value E to be supplied to the electric motor 102 based on the calculated assist steering command value. The ECU 100 acquires, as operation information M, information on an induced voltage from the electric motor 102 or information output from a rotation detection device such as a resolver provided in the electric motor 102.

[0035] The steering force of the operator (driver) input to the steering wheel 81 is transmitted to the first pinion gear 88a. The steering force transmitted to the first pinion gear 88a is then transmitted to the tie rod 89 via the steering gear 88, displacing the wheels.

[0036] Furthermore, the steering force input by the operator to the steering wheel 81 is transmitted to the torque sensor 10, which is arranged in the steering force transmission path from the steering wheel 81 to the first pinion gear 88a. At this time, the ECU 100 acquires the steering torque T from the torque sensor 10 and also acquires the vehicle speed signal V from the vehicle speed sensor 101. Then, the ECU 100 controls the operation of the electric motor 102. The auxiliary steering torque generated by the electric motor 102 is transmitted to the second pinion gear 88c.

[0037] The auxiliary steering torque transmitted to the second pinion gear 88c is transmitted to the tie rod 89 via the steering gear 88, displacing the wheels. That is, the steering device 80 displaces the wheels using not only the steering force of the operator transmitted to the rack bar 88b via the first pinion gear 88a, but also the auxiliary steering torque of the electric motor 102 transmitted to the rack bar 88b via the second pinion gear 88c.

[0038] 1, the steering device 80 is of a dual pinion type in which an assist force is applied to the second pinion gear 88c, but is not limited to this. The steering device 80 may be, for example, a column assist type electric power steering device in which an assist force is applied to the steering shaft 82, or a single pinion assist type electric power steering device in which an assist force is applied to the first pinion gear 88a. Furthermore, the steering device 80 may be a rack assist type electric power steering device in which an assist force is applied to the rack bar 88b without going through a pinion, such as a ball screw type electric power steering device in which an assist force is applied to the rack bar 88b by a ball screw.

[0039] 2 is a cross-sectional view of a main portion including a portion of the stub shaft 87 and the first pinion gear 88a where the torque sensor 10 is disposed. The stub shaft 87 and the first pinion gear 88a are disposed inside a housing 20, which also serves as the housing 20 for the torque sensor 10. The housing 20 has a first housing 20a and a second housing 20b that are connected to each other. The first housing 20a is disposed axially closer to the stub shaft 87 and mainly covers the stub shaft 87, while the second housing 20b is disposed axially closer to the first pinion gear 88a and mainly covers the first pinion gear 88a. In other words, at least a portion of the stub shaft 87 and the first pinion gear 88a are disposed inside the first housing 20a and the second housing 20b, with the stub shaft 87 being disposed at least a portion of the first housing 20a and the first pinion gear 88a being disposed at least a portion of the first housing 20b. The first housing 20a is attached to the second housing 20b with the attachment bolts 28, thereby fixing the first housing 20a to the second housing 20b.

[0040] A bearing (not shown) is disposed inside the first housing 20 a, and the stub shaft 87 is rotatably supported by the first housing 20 a via the bearing disposed inside the first housing 20 a. A bearing (not shown) is also disposed inside the second housing 20 b, and the first pinion gear 88 a is rotatably supported by the second housing 20 b via the bearing disposed inside the second housing 20 b.

[0041] The stub shaft 87 is rotatably supported by the first housing 20a, and the first pinion gear 88a is rotatably supported by the second housing 20b. Therefore, the stub shaft 87 and the first pinion gear 88a, which are connected via the torsion bar 87a, are integrally supported by the first housing 20a and the second housing 20b so as to be rotatable.

[0042] The housing 20 is mounted non-rotatably to the vehicle body, and the housing 20 rotatably supports the stub shaft 87 and the first pinion gear 88a by means of bearings arranged in the first housing 20a and bearings arranged in the second housing 20b.

[0043] The torque sensor 10 is disposed within the first housing 20a and is located near the ends of a stub shaft 87, which is a first shaft, and a first pinion gear 88a, which is a second shaft connected to the stub shaft 87 via a torsion bar 87a. The stub shaft 87 and the first pinion gear 88a are both shafts having hollow portions, and the end of one shaft extends into the other shaft from the end of the other shaft. In this embodiment, the stub shaft 87 extends into the first pinion gear 88a.

[0044] The torsion bar 87a is disposed from the inside of the stub shaft 87 to the inside of the first pinion gear 88a, with one end connected to the stub shaft 87 and the other end connected to the first pinion gear 88a. In other words, the stub shaft 87 and the first pinion gear 88a are not directly connected, but are connected via the torsion bar 87a, which is a shaft-shaped member. As a result, the stub shaft 87 and the first pinion gear 88a are capable of relative rotation, and when torsion occurs in the torsion bar 87a, the stub shaft 87 and the first pinion gear 88a rotate relative to each other in response to the torsion bar 87a twisting.

[0045] The torque sensor 10 is positioned near the end of the stub shaft 87 and the first pinion gear 88a, which are connected via the torsion bar 87a as described above, and by detecting the angle of relative rotation between the stub shaft 87 and the first pinion gear 88a, it is possible to detect the torque acting between the stub shaft 87 and the first pinion gear 88a.

[0046] 3 is a cross-sectional view of a main portion of the torque sensor 10 included in the steering device 80 according to the first embodiment. In the following description, unless a specific direction is specified, the axial direction Z of the stub shaft 87 or the first pinion gear 88 a on which the torque sensor 10 is disposed will also be described as the axial direction Z of the torque sensor 10. Similarly, the circumferential direction centered on the axis of the stub shaft 87 or the first pinion gear 88 a will also be described as the circumferential direction of the torque sensor 10, and the radial direction centered on the axis of the stub shaft 87 or the first pinion gear 88 a will also be described as the radial direction of the torque sensor 10. Furthermore, of the radial directions of the torque sensor 10, the direction along the radial direction at a position where the magnetic flux collecting yoke assembly 40 is disposed in the circumferential direction (the left-right direction on the paper in FIG. 3 ) will be described as the longitudinal direction Y of the torque sensor 10 or the longitudinal direction Y of the magnetic flux collecting yoke assembly 40. Furthermore, the direction orthogonal to both the length direction Y and the axial direction Z (the direction into the plane of the paper in FIG. 3 ) will be described as the width direction X of the torque sensor 10 or the width direction X of the magnetic flux collecting yoke assembly 40. In the first embodiment, the length direction Y is a direction orthogonal to the axial direction Z in a cross section passing through the axial centers of the stub shaft 87 and the first pinion gear 88 a and the center of the magnetic flux collecting yoke assembly 40 in the width direction X.

[0047] The housing 20 is formed in a substantially cylindrical shape, and the stub shaft 87 and the first pinion gear 88a are disposed inside the cylindrical inner circumferential surface 21, and the housing 20 of the torque sensor 10 is provided at a position in a part of the axial direction Z of the housing 20 formed in a substantially cylindrical shape. More specifically, of the first housing 20a and second housing 20b included in the housing 20, the housing 20 of the torque sensor 10 is provided at a position in a part of the axial direction Z of the first housing 20a.

[0048] The torque sensor 10 has a magnetism collecting yoke assembly 40, which is disposed inside the housing 20 and detachably attached to the housing 20. More specifically, of the first housing 20a and the second housing 20b of the housing 20, the first housing 20a has a storage section 26 that stores the magnetism collecting yoke assembly 40, and the storage section 26 is formed in a hole-like shape that opens from the inner circumferential surface 21 of the housing 20 toward the outside in the radial direction.

[0049] The magnetic flux collecting yoke assembly 40 is inserted radially into the storage portion 26 from the radial outside toward the inner circumferential surface 21. In other words, the magnetic flux collecting yoke assembly 40 is inserted into the storage portion 26 in the length direction Y from the radial outside toward the radial inside of the housing 20. In the following description, the direction in which the magnetic flux collecting yoke assembly 40 is inserted into the storage portion 26 is also referred to as the insertion direction.

[0050] The magnetism collecting yoke assembly 40 has a sensor housing 41, inside which are arranged a magnetism collecting yoke 55, a Hall IC 50, and a circuit board 52. The Hall IC 50 is capable of converting changes in magnetic flux detected by the magnetism collecting yoke 55 based on changes in torque transmitted between the stub shaft 87 and the first pinion gear 88a into an electrical signal and outputting the electrical signal. In addition to the magnetism collecting yoke 55, the Hall IC 50, and the circuit board 52 of the magnetism collecting yoke assembly 40, the torque sensor 10 also has a magnet 65 (see FIG. 4) attached to one of the two shafts connected via a torsion bar 87a, and a stator 60 (see FIG. 4) attached to the other shaft.

[0051] FIG. 4 is a schematic diagram illustrating an overview of the magnet 65, stator 60, and magnetic flux collecting yoke 55 of the torque sensor 10. One of the magnet 65 and stator 60 of the torque sensor 10 is attached to a first shaft, and the other is attached to a second shaft. In the first embodiment, the magnet 65 is attached to the outer peripheral surface of a stub shaft 87, which is the first shaft, and the stator 60 is attached to the outer peripheral surface of a first pinion gear 88a, which is the second shaft. The magnet 65 is formed in a substantially cylindrical shape and is an annular permanent magnet in which multiple magnetic poles 66 are alternately arranged in the circumferential direction. That is, the magnet 65 is a multi-pole magnet in which different magnetic poles 66, i.e., north poles 66n and south poles 66s, are alternately arranged in the circumferential direction of the annular magnet 65. In this embodiment, the magnet 65 is a multi-pole magnet with eight pole pairs.

[0052] The stator 60 has a flange portion 61 and teeth portions 62. The teeth portions 62 are portions through which magnetic flux from the magnet 65 flows, and the flange portion 61 is a portion through which the magnetic flux from the magnet 65 flowing from the teeth portions 62 to the stator 60 is channeled to the magnetic flux collecting yoke 55. The flange portion 61 is formed in an annular plate shape with its thickness direction aligned with the axial direction Z. The teeth portions 62 extend from the inner periphery of the annular flange portion 61 toward the axial direction Z of the flange portion 61, and are formed in a plate shape with its thickness direction aligned with the radial direction of the flange portion 61. Furthermore, multiple teeth portions 62 are arranged in a row at intervals in the circumferential direction of the flange portion 61. The number of teeth portions 62 is the same as the number of magnetic poles 66 of the magnet 65.

[0053] The stator 60 thus formed includes a pair of stators 60, a first stator 60a and a second stator 60b, each having an identical shape. The first stator 60a and the second stator 60b each have a flange portion 61 and teeth portions 62. That is, the first stator 60a has an annular first flange portion 61a and a plurality of first teeth portions 62a, and the second stator 60b has an annular second flange portion 61b and a plurality of second teeth portions 62b. The first stator 60a and the second stator 60b are both attached to the same shaft with their flange portions 61 positioned coaxially and oriented in a direction away from the other stator 60. In the first embodiment, the first stator 60a and the second stator 60b are both attached to the outer circumferential surface of the first pinion gear 88a.

[0054] That is, the first stator 60a is disposed with the first teeth 62a extending from the first flange 61a toward the second stator 60b, and the second stator 60b is disposed with the second teeth 62b extending from the second flange 61b toward the first stator 60a. In this case, since multiple first teeth 62a and multiple second teeth 62b are provided at intervals on the first flange 61a and the second flange 61b, the first stator 60a and the second stator 60b are combined such that the teeth 62 of one stator 60 are located in portions of the circumferential direction where the teeth 62 of the other stator 60 are not located.

[0055] The magnet 65 attached to the outer peripheral surface of the stub shaft 87 is disposed radially inward of the first stator 60a and second stator 60b combined in this manner. The magnet 65 and the stator 60 are also disposed such that the axial direction Z of the magnet 65 coincides with the axial direction Z of the stub shaft 87 and the first pinion gear 88a. Therefore, the magnet 65 and the stator 60 are attached to the stub shaft 87 and the first pinion gear 88a in a positional relationship in which the outer peripheral surface of the magnet 65 faces the teeth 62 of the stator 60. Because the magnet 65 and the stator 60 are disposed in this positional relationship, when torque is transmitted between the stub shaft 87 and the first pinion gear 88a via the torsion bar 87a and the stub shaft 87 and the first pinion gear 88a rotate slightly relative to each other, the relative positional relationship between the magnet 65 and the stator 60 changes, and the magnetic flux acting from the magnet 65 on the stator 60 changes accordingly.

[0056] Further, a magnetism collecting yoke 55 of the magnetism collecting yoke assembly 40 is disposed near the stator 60. The magnetism collecting yoke 55 is a member for detecting changes in the magnetic flux acting on the stator 60 from the magnet 65, and is disposed near a flange portion 61 of the stator 60. Since the stator 60 is provided with a pair of a first stator 60a and a second stator 60b, the magnetism collecting yoke 55 is also provided with a pair of a first magnetism collecting yoke 55a and a second magnetism collecting yoke 55b corresponding to the pair. That is, the first magnetism collecting yoke 55a of the magnetism collecting yoke 55 is disposed near the first flange portion 61a of the first stator 60a, and the second magnetism collecting yoke 55b is disposed near the second flange portion 61b of the second stator 60b.

[0057] The pair of magnetic flux collecting yokes 55 are located radially outward of the teeth 62 of the stator 60, between two flange portions 61 of the stator 60, and overlap with the flange portions 61 of the stator 60 with a gap in the axial direction Z. That is, the first magnetic flux collecting yoke 55a is located near the surface of the first flange portion 61a of the first stator 60a where the second flange portion 61b is located, and the second magnetic flux collecting yoke 55b is located near the surface of the second flange portion 61b of the second stator 60b where the first flange portion 61a is located. These magnetic flux collecting yokes 55 overlap with the flange portions 61 of the stator 60 within a predetermined range in the circumferential direction.

[0058] The pair of magnetic flux collecting yokes 55 may be arranged in a positional relationship such that the pair of magnetic flux collecting yokes 55 sandwich the two flange portions 61 of the pair of stators 60 from both sides in the axial direction Z. That is, the first magnetic flux collecting yoke 55a may be arranged near a surface of the first flange portion 61a of the first stator 60a opposite to the side where the second flange portion 61b is located, and the second magnetic flux collecting yoke 55b may be arranged near a surface of the second flange portion 61b of the second stator 60b opposite to the side where the first flange portion 61a is located. As long as the pair of magnetic flux collecting yokes 55 overlap the flange portion 61 of the stator 60 near the flange portion 61 within a predetermined range in the circumferential direction, the pair of magnetic flux collecting yokes 55 may be arranged between the first flange portion 61a and the second flange portion 61b, or may be arranged in a positional relationship such that the pair of magnetic flux collecting yokes 55 sandwich the first flange portion 61a and the second flange portion 61b from both sides in the axial direction Z.

[0059] In this way, by positioning the magnetic flux collecting yokes 55 near the flange portion 61, the pair of magnetic flux collecting yokes 55 can detect changes in magnetic flux corresponding to changes in the relative positions of the pair of stators 60 and the magnet 65. In other words, the magnetic flux collecting yokes 55 can detect changes in the magnetic flux acting on the stator 60 from the magnet 65 when the stub shaft 87 and the first pinion gear 88 a rotate slightly relative to each other.

[0060] Furthermore, a Hall IC 50 is disposed between the two magnetic flux collecting yokes 55. The Hall IC 50 is disposed between the magnetic flux collecting yokes 55 at a position away from a portion of the magnetic flux collecting yoke 55 located near the flange portion 61 of the stator 60. In other words, the Hall IC 50 is sandwiched between the first magnetic flux collecting yoke 55a and the second magnetic flux collecting yoke 55b of the magnetic flux collecting yoke 55. An adhesive layer 56 is filled between the first magnetic flux collecting yoke 55a, the second magnetic flux collecting yoke 55b, and the Hall IC 50. The Hall IC 50 is fixed to the first magnetic flux collecting yoke 55a and the second magnetic flux collecting yoke 55b via the adhesive layer 56.

[0061] The Hall IC 50 has a Hall element (not shown) that detects changes in magnetic flux detected by the magnetism collecting yokes 55, and an output circuit (not shown) that converts the output voltage output from the Hall element in response to changes in magnetic flux into a digital electrical signal. This allows the Hall IC 50 to detect changes in magnetic flux density acting on the two magnetism collecting yokes 55, convert the detected changes in magnetic flux density into an electrical signal, and output it as an electrical signal. Note that a magnetic sensor that utilizes the magnetoresistance effect or the tunnel magnetoresistance effect can be used instead of the Hall IC 50. In short, it is sufficient if it can output changes in magnetic flux density occurring between the magnetism collecting yokes 55 as an electrical signal.

[0062] 2, the magnet 65 is attached to the stub shaft 87 by a first sleeve 67. The first sleeve 67 is a cylindrical member, and the first sleeve 67 is attached to the stub shaft 87 by press-fitting the stub shaft 87 into the first sleeve 67. The magnet 65 is fixed to the outer peripheral surface of the first sleeve 67 by, for example, an adhesive, so that the magnet 65 can rotate integrally with the stub shaft 87.

[0063] As shown in FIG. 2 , the stator 60 is attached to the first pinion gear 88a by the second sleeve 63 and the carrier 64. The second sleeve 63 is a cylindrical member, and the first pinion gear 88a is press-fitted into the second sleeve 63, thereby attaching the second sleeve 63 to the first pinion gear 88a. The carrier 64 is also a cylindrical member, and is formed integrally with the second sleeve 63. Therefore, by attaching the second sleeve 63 to the first pinion gear 88a, the carrier 64 is attached to the first pinion gear 88a together with the second sleeve 63.

[0064] The carrier 64, which is attached to the first pinion gear 88a by the second sleeve 63, is supported by the second sleeve 63 and is positioned from the first pinion gear 88a toward the stub shaft 87, and is positioned radially outward from the stub shaft 87. Furthermore, the carrier 64 is positioned in the same position as the magnet 65 in the axial direction Z, and is positioned radially outward from the magnet 65.

[0065] The stators 60 are attached to the carrier 64 arranged in this manner. More specifically, the first stator 60a and the second stator 60b are attached to the carrier 64 with the teeth 62 located radially inside the carrier 64 and the flanges 61 protruding from the radially inside to the radially outside of the carrier 64. As a result, the pair of stators 60, the first stator 60a and the second stator 60b, are both arranged in the same position as the magnet 65 in the axial direction, and are arranged radially outside the magnet 65.

[0066] Furthermore, the first stator 60a and the second stator 60b are attached to a carrier 64 that is formed integrally with the second sleeve 63 that is attached to the first pinion gear 88a, and are therefore rotatable integrally with the first pinion gear 88a. In this way, the magnet 65 is fixed to the stub shaft 87, and the stator 60 is fixed to the first pinion gear 88a, so that the magnet 65 and the stator 60 are disposed inside the housing 20 together with the stub shaft 87 and the first pinion gear 88a.

[0067] In the torque sensor 10 configured as above, when the stub shaft 87 and the first pinion gear 88a rotate relative to each other due to a slight twisting of the torsion bar 87a, the magnet 65 and the stator 60 also rotate relative to each other, and the change in magnetic flux acting on the stator 60 at that time is detected by the magnetic collecting yoke 55.

[0068] The Hall IC 50, which converts changes in magnetic flux detected by the magnetic flux collecting yoke 55 into an electrical signal, is connected to the circuit board 52 by a lead frame 51. The magnetic flux collecting yoke assembly 40 is configured such that the magnetic flux collecting yoke 55 and the Hall IC 50, which are disposed inside the sensor housing 41, are positioned at desired positions by attaching the sensor housing 41 to the housing 20.

[0069] Fig. 5 is a cross-sectional view of the housing 20 shown in Fig. 3. The first housing 20a of the housing 20 has a seal member abutment portion 25 located radially outward of a storage portion 26 that opens radially outward from the inner circumferential surface 21 of the housing 20. That is, the seal member abutment portion 25 is located radially opposite the side of the storage portion 26 where the inner circumferential surface 21 of the housing 20 is located. In other words, the seal member abutment portion 25 is located closer to the entrance than the storage portion 26 in the insertion direction of the magnetic flux collecting yoke assembly 40 (see Fig. 3) into the storage portion 26.

[0070] The seal member abutment portion 25 is formed in a hole-like shape that opens in the radial direction, similar to the storage portion 26, and the size of the hole is larger than that of the storage portion 26. Therefore, a storage portion inner wall 27, which is the inner wall of the storage portion 26, and the seal member abutment portion 25 are formed to have a step relative to each other.

[0071] 6 is a plan view of the magnetic flux collecting yoke assembly 40 as seen in the direction of the arrows A-A in FIG. 3. The magnetic flux collecting yoke assembly 40 has a sensor housing 41 made of a resin material and including a flange portion 42, a connector portion 43, a seal member placement portion 44, and a protrusion 45. The flange portion 42 is a plate-shaped portion that attaches the sensor housing 41 to the housing 20. The flange portion 42 is formed with bolt holes (not shown) through which mounting bolts (not shown) that attach the magnetic flux collecting yoke assembly 40 to the housing 20 pass. The sensor housing 41 is attached to the housing 20 by attaching the flange portion 42 with mounting bolts to the radially outer end surface of the portion of the housing 20 where the storage portion 26 is formed.

[0072] The connector portion 43 is disposed radially outward from the flange portion 42 when the magnetism collecting yoke assembly 40 is attached to the housing 20. The connector portion 43 has terminals extending from the Hall IC 50 of the magnetism collecting yoke assembly 40 disposed on the inner side thereof, and serves as a portion that connects the terminals extending from the Hall IC 50 to external terminals. The magnetism collecting yoke assembly 40 can electrically connect the torque sensor 10 and the ECU 100 by connecting the terminals extending from the Hall IC 50 to external terminals at the connector portion 43.

[0073] When the magnetic flux collecting yoke assembly 40 is attached to the housing 20, the seal member arrangement portion 44 and the protrusion 45 are disposed radially inward of the flange portion 42. Specifically, the seal member arrangement portion 44 is disposed closer to the flange portion 42 than the protrusion 45 in the longitudinal direction Y, and the protrusion 45 is disposed on the opposite side of the seal member arrangement portion 44 from the flange portion 42 in the longitudinal direction Y. The seal member arrangement portion 44 is a location where an O-ring 70 (see FIG. 7 ), which will be described later, can be disposed. Specifically, the torque sensor 10 according to the first embodiment can be used in either a waterproof or non-waterproof configuration. When used in the waterproof configuration, the O-ring 70 is disposed in the seal member arrangement portion 44, and when used in the non-waterproof configuration, the O-ring 70 is not disposed in the seal member arrangement portion 44.

[0074] The protruding portion 45 protrudes from the position where the seal member arrangement portion 44 is arranged in the longitudinal direction Y toward the side opposite to the side where the flange portion 42 is located. A space is formed inside the protruding portion 45, and the Hall IC 50 of the magnetic flux collecting yoke assembly 40 is arranged inside the protruding portion 45 of the sensor housing 41.

[0075] The protrusion 45 has an end 45a on the opposite side in the longitudinal direction Y to the side where the seal member arrangement portion 44 is located, which is formed to have a curved shape that is recessed toward the side where the seal member arrangement portion 44 is located in the longitudinal direction Y when the sensor housing 41 is viewed in the axial direction Z. The curved shape of the end 45a of the protrusion 45 is an arc shape whose center substantially coincides with the axis of the stub shaft 87 (see FIG. 2) and the first pinion gear 88a (see FIG. 2) when the magnetic flux collecting yoke assembly 40 is attached to the housing 20.

[0076] The protruding portion 45 has a smaller width in both the width direction X and the axial direction Z than the seal member arrangement portion 44. In other words, the size of the protruding portion 45 when viewed in the longitudinal direction Y of the sensor housing 41 is smaller than that of the seal member arrangement portion 44 around the entire circumference of the protruding portion 45. In other words, the outline shape of the protruding portion 45 when viewed in the direction in which the protruding portion 45 is inserted into the storage portion 26 of the housing 20 is smaller than the outline shape of the seal member arrangement portion 44. As a result, the protruding portion 45 has a step with respect to the seal member arrangement portion 44.

[0077] Additionally, an inclined connection portion 48 is provided between the seal member arrangement portion 44 and the protrusion 45 in the sensor housing 41. The inclined connection portion 48 is inclined with respect to the insertion direction of the protrusion 45 into the storage portion 26 of the housing 20, and connects the seal member arrangement portion 44, which is formed with a step, to the protrusion 45. In other words, the inclined connection portion 48 is inclined with respect to the length direction Y in a direction in which the distance from the protrusion 45 in the width direction X and the distance from the protrusion 45 in the axial direction Z become smaller as the inclined connection portion 48 moves from the side where the seal member arrangement portion 44 is located to the side where the protrusion 45 is located.

[0078] The protruding portion 45 also has a plurality of crush ribs 47 on its outer peripheral surface 46. The crush ribs 47 protrude from the outer peripheral surface 46 of the protruding portion 45 and are formed in a rib-like shape extending in the longitudinal direction Y from a position near the seal member arrangement portion 44. The sensor housing 41 is made of a resin material, and the seal member arrangement portion 44, the protruding portion 45, the inclined connecting portion 48, and the crush ribs 47 are integrally formed. More specifically, the crush ribs 47 are connected to the inclined connecting portion 48 at the end on the side where the seal member arrangement portion 44 is located in the insertion direction of the protruding portion 45 into the storage portion 26 of the housing 20, and extend in the longitudinal direction Y from the position of the inclined connecting portion 48. The height of the crush ribs 47 from the outer peripheral surface 46 of the protruding portion 45 is smaller than the height of the seal member arrangement portion 44 from the outer peripheral surface 46 of the protruding portion 45. The width of the crush ribs 47 is wider than the height of the crush ribs 47, but is relatively narrow.

[0079] Furthermore, the length Lr of the crush rib 47 in the longitudinal direction Y from the seal member arrangement portion 44 is shorter than the combined length Lp of the protrusion 45 and the inclined connecting portion 48. In other words, the length Lr of the crush rib 47 from the position of the seal member arrangement portion 44 in the insertion direction of the protrusion 45 to the end of the crush rib 47 opposite the side where the seal member arrangement portion 44 is located is shorter than the combined length Lp of the protrusion 45 and the inclined connecting portion 48 in the insertion direction of the protrusion 45. In this case, the combined length Lp of the protrusion 45 and the inclined connecting portion 48 is the length of the longest portion of the protrusion 45 in the longitudinal direction Y from the position of the seal member arrangement portion 44.

[0080] A plurality of crush ribs 47 are arranged on the protruding portion 45, and the length Lr of all of the crush ribs 47 arranged on the protruding portion 45 is shorter than the combined length Lp of the protruding portion 45 and the inclined connecting portion 48. Furthermore, the plurality of crush ribs 47 arranged on the protruding portion 45 are formed so that the length Lr from the position of the seal member arrangement portion 44 is substantially the same.

[0081] Fig. 7 is a schematic diagram showing a state in which the protrusion 45 of the magnetic flux collecting yoke assembly 40 is stored in the storage section 26 of the housing 20. Fig. 8 is a cross-sectional view taken along line B-B of Fig. 7. When attaching the magnetic flux collecting yoke assembly 40 to the housing 20, the protrusion 45 of the sensor housing 41 of the magnetic flux collecting yoke assembly 40 is inserted into the storage section 26 in a direction that protrudes from the flange portion 42 toward the side of the housing 20 where the storage section 26 is located in the longitudinal direction Y. After the protrusion 45 of the sensor housing 41 is inserted into the storage section 26 and stored in the storage section 26, the flange portion 42 of the sensor housing 41 is attached to the housing 20 with mounting bolts (not shown). As a result, the magnetic collecting yoke assembly 40 is attached to the housing 20 with the protrusion 45 of the sensor housing 41 stored in the storage section 26 of the housing 20 and the Hall IC 50 (see Figure 3) placed inside the protrusion 45 positioned in the desired position.

[0082] When the protrusion 45 of the sensor housing 41 is stored in the storage section 26 of the housing 20, the multiple crush ribs 47 arranged on the outer peripheral surface 46 of the protrusion 45 each abut against the storage section inner wall 27, which is the inner wall of the storage section 26. In other words, the multiple crush ribs 47 arranged on the outer peripheral surface 46 of the protrusion 45 have a height from the outer peripheral surface 46 that is equal to the distance between the outer peripheral surface 46 of the protrusion 45 and the storage section inner wall 27, and is slightly higher than the distance between the outer peripheral surface 46 of the protrusion 45 and the storage section inner wall 27. Therefore, the multiple crush ribs 47 arranged on the outer peripheral surface 46 of the protrusion 45 each abut against the storage section inner wall 27.

[0083] At this time, because the sensor housing 41 is made of a resin material, the crush ribs 47 elastically deform and slightly crush as they abut against the storage section inner wall 27. In the first embodiment, the crush ribs 47 are arranged on the outer peripheral surface 46 on both sides of the protrusion 45 in the axial direction Z and on both sides of the outer peripheral surface 46 of the protrusion 45 in the width direction X, which is a direction perpendicular to both the axial direction Z and the length direction Y. More specifically, in the first embodiment, the crush ribs 47 are arranged in two locations on each side of the outer peripheral surface 46 of the protrusion 45 in the axial direction Z and in one location on each end in the width direction X, so that a total of six crush ribs 47 abut against the storage section inner wall 27.

[0084] The crush rib 47 abutting against the storage section inner wall 27 has a length Lr in the insertion direction of the protrusion 45 into the storage section 26 that is shorter than the combined length Lp of the protrusion 45 and the inclined connecting portion 48 in the insertion direction of the protrusion 45. Therefore, the crush rib 47 abuts against the storage section inner wall 27 at a length that is shorter than the combined length Lp of the protrusion 45 and the inclined connecting portion 48 in the insertion direction of the protrusion 45 into the storage section 26. In other words, when the protrusion 45 of the sensor housing 41 of the magnetic flux collecting yoke assembly 40 is stored in the storage section 26 of the housing 20, the abutment length Lc of the crush rib 47 against the storage section inner wall 27 is shorter than the combined length Lp of the protrusion 45 and the inclined connecting portion 48.

[0085] Furthermore, the torque sensor 10 according to the first embodiment can be used with an O-ring 70 disposed in the seal member disposing portion 44 when used in a waterproof specification, and can be used without disposing the O-ring 70 in the seal member disposing portion 44 when used in a non-waterproof specification. Therefore, when used in a waterproof specification, the magnetic flux collecting yoke assembly 40 has the protrusion 45 stored inside the storage portion 26 with the O-ring 70, which is a seal member, disposed in the seal member disposing portion 44 of the sensor housing 41. Because the O-ring 70 is an annular member made of a rubber material, the annular O-ring 70 is disposed in the seal member disposing portion 44 of the sensor housing 41 around the entire periphery of the seal member disposing portion 44 when the sensor housing 41 is viewed in the longitudinal direction Y.

[0086] On the other hand, the housing 20 has the seal member abutment portion 25 on the inlet side of the storage portion 26 in the insertion direction when the protrusion 45 is inserted into the storage portion 26. Therefore, when the protrusion 45 of the sensor housing 41 is stored in the storage portion 26 of the housing 20, the O-ring 70 arranged in the seal member arrangement portion 44 of the sensor housing 41 abuts against the inner circumferential surface of the seal member abutment portion 25.

[0087] The O-ring 70 of the magnetic flux collecting yoke assembly 40 is thus arranged in the seal member arrangement portion 44 of the sensor housing 41, and abuts against both the seal member arrangement portion 44 of the sensor housing 41 and the seal member abutment portion 25 of the housing 20 at a position closer to the entrance than the storage portion 26 in the insertion direction when the protrusion 45 is inserted into the storage portion 26. In this way, the O-ring 70 ensures sealing between the sensor housing 41 and the housing 20 at a position closer to the entrance than the storage portion 26 in the insertion direction when the protrusion 45 is inserted into the storage portion 26.

[0088] 9 is an exploded perspective view of the stub shaft 87, the first pinion gear 88a, and the torque sensor 10. An insertion hole 881, into which the stub shaft 87 is inserted, is formed at the end of the first pinion gear 88a on the side where the stub shaft 87 is located. An uneven portion 882 is formed on the inner circumferential surface of the insertion hole 881 of the first pinion gear 88a. The uneven portion 882 includes a plurality of convex portions 882b that protrude radially inward on the inner circumferential surface of the insertion hole 881, and a plurality of concave portions 882a that recess radially outward on the inner circumferential surface of the insertion hole 881, which are alternately arranged in the circumferential direction of the insertion hole 881. The convex portions 882b and the concave portions 882a are formed so that the axial length of the first pinion gear 88a is the same as the axial length of the insertion hole 881.

[0089] On the other hand, the stub shaft 87 has an insertion portion 871, which is a portion of the stub shaft 87 that is inserted into the insertion hole 881 of the first pinion gear 88a. The insertion portion 871 of the stub shaft 87 is located at the end of the stub shaft 87 on the side where the first pinion gear 88a is located. The insertion portion 871 of the stub shaft 87 has uneven portions 872 formed on its outer circumferential surface that correspond to the uneven portions 882 formed in the insertion hole 881 of the first pinion gear 88a. That is, the uneven portion 872 formed on the insertion portion 871 is made up of a plurality of recesses 872a recessed radially inward of the insertion portion 871 and a plurality of protrusions 872b protruding radially outward of the insertion portion 871, which are arranged alternately in the circumferential direction of the insertion portion 871.

[0090] The number of recesses 872a and protrusions 872b of the uneven portion 872 formed in the insertion portion 871 of the stub shaft 87 is the same as the number of recesses 882a and protrusions 882b of the uneven portion 882 formed in the insertion hole 881 of the first pinion gear 88a. Furthermore, the number of recesses 882a and protrusions 882b formed in the insertion hole 881 of the first pinion gear 88a and the number of recesses 872a and protrusions 872b formed in the insertion portion 871 of the stub shaft 87 are the same as the number of first teeth 62a of the first stator 60a (see FIG. 4) and the number of second teeth 62b of the second stator 60b (see FIG. 4).

[0091] In this embodiment, the number of recesses 882a and the number of protrusions 882b formed in the insertion hole 881 of the first pinion gear 88a are eight, and the number of recesses 872a and the number of protrusions 872b formed in the insertion portion 871 of the stub shaft 87 are also eight. Similarly, the number of first teeth 62a of the first stator 60a and the number of second teeth 62b of the second stator 60b are also eight.

[0092] An uneven portion 882 is formed in the insertion hole 881 of the first pinion gear 88a, and an uneven portion 872 is formed in the insertion portion 871 of the stub shaft 87, so when the insertion portion 871 of the stub shaft 87 is inserted into the insertion hole 881 of the first pinion gear 88a, the uneven portion 872 of the insertion portion 871 of the stub shaft 87 fits into the uneven portion 882 of the insertion hole 881 of the first pinion gear 88a. In other words, when the insertion portion 871 of the stub shaft 87 is inserted into the insertion hole 881 of the first pinion gear 88a, the convex portion 872b formed on the insertion portion 871 of the stub shaft 87 fits into the recessed portion 882a formed in the insertion hole 881 of the first pinion gear 88a, and the convex portion 882b formed in the insertion hole 881 of the first pinion gear 88a fits into the recessed portion 872a formed in the insertion portion 871 of the stub shaft 87.

[0093] Here, the size of the convex portion 872b formed in the insertion portion 871 of the stub shaft 87 in the circumferential direction of the stub shaft 87 is smaller than the size of the concave portion 882a formed in the insertion hole 881 of the first pinion gear 88a in the circumferential direction of the stub shaft 87. Similarly, the size of the convex portion 882b formed in the insertion hole 881 of the first pinion gear 88a in the circumferential direction of the first pinion gear 88a is smaller than the size of the concave portion 872a formed in the insertion portion 871 of the stub shaft 87 in the circumferential direction of the first pinion gear 88a.

[0094] Therefore, when the insertion portion 871 of the stub shaft 87 is inserted into the insertion hole 881 of the first pinion gear 88a, the uneven portion 872 of the stub shaft 87 and the uneven portion 882 of the first pinion gear 88a do not come into contact with each other, and the insertion portion 871 of the stub shaft 87 is inserted into the insertion hole 881 of the first pinion gear 88a.

[0095] In other words, when the insertion portion 871 of the stub shaft 87 is inserted into the insertion hole 881 of the first pinion gear 88a, the convex portions 872b formed on the insertion portion 871 of the stub shaft 87 are disposed between adjacent convex portions 882b in the concave-convex portion 882 of the first pinion gear 88a without coming into contact with the convex portions 882b formed in the insertion hole 881 of the first pinion gear 88a. Therefore, when the insertion portion 871 of the stub shaft 87 is inserted into the insertion hole 881 of the first pinion gear 88a, the concave-convex portion 872 of the stub shaft 87 and the concave-convex portion 882 of the first pinion gear 88a do not come into contact with each other, and torque is transmitted between the stub shaft 87 and the first pinion gear 88a via the torsion bar 87a.

[0096] The uneven portion 872 of the insertion portion 871 of the stub shaft 87 and the uneven portion 882 of the insertion hole 881 of the first pinion gear 88a, which are formed in this manner, do not abut during normal steering, but come into abutment when the torsion angle of the torsion bar 87a becomes larger than a predetermined angle. In other words, when the torsion angle of the torsion bar 87a becomes larger than the predetermined torsion angle, the uneven portion 872 of the insertion portion 871 of the stub shaft 87 and the uneven portion 882 of the insertion hole 881 of the first pinion gear 88a abut against each other, thereby preventing the relative rotational angle difference in the circumferential direction between the stub shaft 87 and the first pinion gear 88a from becoming larger than the torsion angle that would damage the torsion bar 87a, thereby suppressing damage to the torsion bar 87a that would result from the torsion angle becoming too large.

[0097] The magnet 65 and stator 60 of the torque sensor 10 are disposed on the stub shaft 87 and first pinion gear 88a formed in this manner, respectively. That is, the magnet 65 is disposed on the stub shaft 87, and the stator 60 is disposed on the first pinion gear 88a. The magnet 65 disposed on the stub shaft 87 is attached to the stub shaft 87 in such a manner that its circumferential orientation is such that the boundary between the south pole 66s and the north pole 66n of the magnet 65 is located at the circumferential center of a protrusion 872b formed on an insertion portion 871 of the stub shaft 87.

[0098] The stator 60 disposed on the first pinion gear 88a is attached to the first pinion gear 88a in an orientation in the circumferential direction such that the circumferential positions of the recesses 882a or the protrusions 882b formed in the insertion hole 881 of the first pinion gear 88a are the same as the circumferential positions of the teeth 62 of the stator 60. For example, the stator 60 is attached to the first pinion gear 88a in an orientation such that the circumferential positions of the recesses 882a formed in the insertion hole 881 of the first pinion gear 88a are the same as the circumferential positions of the first teeth 62a of the first stator 60a, and the circumferential positions of the protrusions 882b formed in the insertion hole 881 are the same as the circumferential positions of the second teeth 62b of the second stator 60b.

[0099] The positional relationship between the concave-convex portion 872 of the insertion portion 871 and the teeth 62 of the stator 60 may be reversed. That is, the stator 60 may be attached to the first pinion gear 88a in an orientation such that the circumferential position of the concave portion 882a in the insertion portion 871 is the same as the circumferential position of the second teeth 62b, and the circumferential position of the convex portion 882b is the same as the circumferential position of the first teeth 62a.

[0100] In this case, the number of recesses 882a and protrusions 882b formed in the insertion hole 881 of the first pinion gear 88a is the same as the number of first teeth 62a and second teeth 62b of the first stator 60a and the second stator 60b. Therefore, when attaching the stator 60 to the first pinion gear 88a, circumferential phase alignment can be easily performed when attaching the stator 60 to the first pinion gear 88a by aligning the circumferential position of any one of the multiple teeth 62 of the stator 60 with the recesses 882a or protrusions 882b formed in the insertion hole 881 of the first pinion gear 88a. This makes it possible to reduce the number of assembly steps required when attaching the stator 60 to the first pinion gear 88a by aligning the circumferential phase of the stator 60 to the first pinion gear 88a.

[0101] The number of recesses 882a and protrusions 882b formed in the insertion hole 881 of the first pinion gear 88a does not have to be the same as the number of first teeth 62a and second teeth 62b of the first stator 60a and the second stator 60b. For example, the number of recesses 882a and protrusions 882b formed in the insertion hole 881 of the first pinion gear 88a and the number of teeth 62 of the stator 60 may be multiples of the number of the other recesses 882a and protrusions 882b formed in the insertion hole 881 of the first pinion gear 88a and the number of teeth 62 of the stator 60. Even if the number of recesses 882a and protrusions 882b formed in the insertion hole 881 is different from the number of teeth 62 of the stator 60, by providing one in multiples of the other, the circumferential position of any one of the teeth 62 can be aligned with the recesses 882a or protrusions 882b, thereby circumferential phase alignment can be easily performed when attaching the stator 60 to the first pinion gear 88a.

[0102] With the magnet 65 and stator 60 respectively arranged as described above, the stub shaft 87 and the first pinion gear 88a are connected via the torsion bar 87a by inserting the insertion portion 871 of the stub shaft 87 into the insertion hole 881 of the first pinion gear 88a. As a result, the stub shaft 87 and the first pinion gear 88a are connected in an orientation such that the positions of the boundaries between the magnetic poles 66 of the magnet 65 arranged on the stub shaft 87 and the central positions in the circumferential direction of the teeth portion 62 of the stator 60 arranged on the first pinion gear 88a coincide with each other in the circumferential direction.

[0103] Next, the operation of the steering device 80 will be described. When the steering wheel 81 is operated while driving a vehicle equipped with the steering device 80, the steering force applied to the steering wheel 81 is transmitted from the steering wheel 81 to the steering shaft 82. The steering force transmitted to the steering shaft 82 is transmitted as steering torque from the steering shaft 82 to the intermediate shaft 85, and from the intermediate shaft 85 via the stub shaft 87 to the first pinion gear 88a. As a result, the steering gear 88 having the first pinion gear 88a converts the rotational motion transmitted from the first pinion gear 88a into linear motion of the rack bar 88b, causing the tie rod 89 to operate.

[0104] The steering device 80 according to the first embodiment also has an electric motor 102 that generates an auxiliary steering torque to assist the driver in steering. The electric motor 102 generates the auxiliary steering torque based on the steering torque detected by the torque sensor 10 that is disposed between the stub shaft 87 and the first pinion gear 88 a.

[0105] Torque sensor 10 detects the steering torque applied to stub shaft 87 based on the angle of relative rotation between stub shaft 87 and first pinion gear 88a. In other words, because stub shaft 87 and first pinion gear 88a are connected via torsion bar 87a, when steering torque is applied to stub shaft 87, the steering torque is transmitted between stub shaft 87 and first pinion gear 88a via torsion bar 87a. At that time, slight twisting of torsion bar 87a causes relative rotation between stub shaft 87 and first pinion gear 88a.

[0106] In torque sensor 10, relative rotation between stub shaft 87 and first pinion gear 88a causes relative rotation between magnet 65 and stator 60. When magnet 65 and stator 60 rotate relative to each other in this manner, torque sensor 10 detects changes in magnetic flux acting on stator 60 using magnetism collecting yoke 55, converts the changes into an electrical signal using Hall IC 50, and transmits the signal to ECU 100. In other words, torque sensor 10 detects changes in magnetic flux acting from magnet 65 to stator 60 using magnetism collecting yoke 55 and Hall IC 50, thereby detecting the steering torque applied to stub shaft 87, and transmits the detected steering torque to ECU 100 as an electrical signal.

[0107] The ECU 100 operates the electric motor 102 based on the electrical signal transmitted from the torque sensor 10, causing the electric motor 102 to generate an assist steering torque. In other words, the electrical signal transmitted from the Hall IC 50 of the torque sensor 10 to the ECU 100 changes based on the steering torque T acting between the stub shaft 87 and the first pinion gear 88 a. Therefore, the ECU 100 uses the electrical signal transmitted from the Hall IC 50 of the torque sensor 10 as information that changes depending on the steering torque T acting on the stub shaft 87 and the first pinion gear 88 a, and adjusts the power value E supplied to the electric motor 102 based on the electrical signal transmitted from the Hall IC 50, causing the electric motor 102 to generate an assist steering torque.

[0108] That is, the ECU 100 acquires a signal of steering torque T from the torque sensor 10, acquires a vehicle speed signal V of the vehicle from the vehicle speed sensor 101, and further acquires operation information M of the electric motor 102 from a rotation detection device provided in the electric motor 102. Based on this operation information M, the steering torque T, and the vehicle speed signal V, the ECU 100 causes the electric motor 102 to generate an auxiliary steering torque. The auxiliary steering torque generated by the electric motor 102 is transmitted to the second pinion gear 88c. The steering gear 88 having the second pinion gear 88c converts the rotational motion transmitted from the second pinion gear 88c into linear motion of the rack bar 88b. As a result, the steering force applied to the steering wheel 81 by the driver is assisted by the auxiliary steering torque generated by the electric motor 102.

[0109] Thus, when the torque sensor 10 that detects the steering torque applied by the driver is used in a waterproof configuration, an O-ring 70 is disposed between the magnetism collecting yoke assembly 40 and the housing 20 to ensure waterproofing. The O-ring 70 ensures sealing by abutting against both the inner circumferential surface of the seal member abutment portion 25 of the housing 20 and the outer circumferential surface of the seal member arrangement portion 44 of the magnetism collecting yoke assembly 40, thereby ensuring waterproofing against water that may infiltrate the storage portion 26 from outside the housing 20. The O-ring 70 is made of an elastic member, and when abutting against the seal member abutment portion 25 of the housing 20 and the seal member arrangement portion 44 of the magnetism collecting yoke assembly 40, it elastically deforms and abuts in a crushed state, thereby ensuring sealing.

[0110] The O-ring 70 is arranged in a state of contact with both the magnetism collecting yoke assembly 40 and the housing 20 by inserting the protruding portion 45 of the magnetism collecting yoke assembly 40 into the storage portion 26 of the housing 20 with the O-ring 70 arranged in the seal member arrangement portion 44 of the magnetism collecting yoke assembly 40. For this reason, if there is an error in the installation of the magnetism collecting yoke assembly 40 relative to the housing 20, the way in which the O-ring 70 is crushed will change depending on the installation error, and the sealing ability of the O-ring 70 will also change, and in some cases the sealing ability of the O-ring 70 may decrease.

[0111] In this way, if an error occurs in attaching the magnetism collecting yoke assembly 40 to the housing 20, there is a possibility that the sealing performance of the O-ring 70 will be reduced, so crush ribs 47 are arranged on the outer peripheral surface 46 of the protruding portion 45 of the sensor housing 41 of the magnetism collecting yoke assembly 40. By arranging the crush ribs 47 on the protruding portion 45 of the sensor housing 41, the magnetism collecting yoke assembly 40 can be attached to the housing 20 while positioning the magnetism collecting yoke assembly 40 relative to the housing 20 when storing the protruding portion 45 of the magnetism collecting yoke assembly 40 in the storage portion 26 of the housing 20.

[0112] That is, when storing the protrusion 45 of the magnetic flux collecting yoke assembly 40 in the storage section 26 of the housing 20, the crush ribs 47 are brought into contact with the storage section inner wall 27, and the crush ribs 47 and the portions of the protrusion 45 where the crush ribs 47 are located are slightly deformed while the protrusion 45 is stored in the storage section 26. In other words, the magnetic flux collecting yoke assembly 40 can be attached to the housing 20 while the protrusion 45 of the magnetic flux collecting yoke assembly 40 is press-fitted into the storage section 26 of the housing 20. Therefore, the magnetic flux collecting yoke assembly 40 can be positioned relative to the housing 20.

[0113] However, if the compressive force exerted by the housing 20 on the protruding portion 45 of the magnetic flux collecting yoke assembly 40 is large, the amount of deformation of the protruding portion 45 increases, and the inclined connection portion 48 and the seal member arrangement portion 44 may also deform in accordance with the deformation of the protruding portion 45. If the seal member arrangement portion 44 deforms, the pressure from the seal member arrangement portion 44 on the O-ring 70 arranged in the seal member arrangement portion 44 changes, and the way the O-ring 70 is crushed between the seal member arrangement portion 44 of the magnetic flux collecting yoke assembly 40 and the seal member abutment portion 25 of the housing 20 also changes, which may make it difficult to ensure sealing performance.

[0114] In contrast, in the first embodiment, the crush rib 47 arranged on the protruding portion 45 of the magnetic flux collecting yoke assembly 40 has an abutment length Lc in the longitudinal direction Y with respect to the storage section inner wall 27 of the housing 20 that is shorter than the combined length Lp of the protruding portion 45 and the inclined connecting portion 48 in the longitudinal direction Y, which makes it possible to reduce the range of deformation of the protruding portion 45 when the crush rib 47 abuts against the storage section inner wall 27. This makes it possible to suppress deformation of the seal member arrangement portion 44 that accompanies deformation of the protruding portion 45 due to the crush rib 47 abutting against the storage section inner wall 27, and makes it possible to uniformly crush the O-ring 70 arranged between the seal member arrangement portion 44 of the magnetic flux collecting yoke assembly 40 and the seal member abutment portion 25 of the housing 20. Therefore, the O-ring 70 can ensure sealing between the seal member arrangement portion 44 and the O-ring 70, and between the seal member abutment portion 25 and the O-ring 70, all around the O-ring 70, ensuring uniform sealing around the entire circumference of the O-ring 70.

[0115] 10 is a schematic diagram of the magnetic flux collecting yoke assembly 40 and the storage section 26 when the torque sensor 10 is used in a non-waterproof configuration. When the torque sensor 10 is used in a non-waterproof configuration, as shown in Fig. 10, the O-ring 70 is not placed in the seal member placement section 44, and the protrusion 45 of the magnetic flux collecting yoke assembly 40 is stored in the storage section 26 of the housing 20. This allows the torque sensor 10 to be configured to suit both waterproof and non-waterproof specifications using parts that are common to both specifications.

[0116] Even when the torque sensor 10 is used in this non-waterproof configuration, when the protruding portion 45 of the magnetic flux collection yoke assembly 40 is stored in the storage portion 26 of the housing 20, the crush ribs 47 arranged on the protruding portion 45 come into contact with the storage portion inner wall 27. This positions the magnetic flux collection yoke assembly 40 relative to the housing 20. Therefore, the magnetic flux collection yoke assembly 40 is attached to the housing 20 with the magnetic flux collection yoke 55 arranged inside the sensor housing 41 positioned relative to the stator 60 attached to the first pinion gear 88a.

[0117] That is, the crush ribs 47 arranged on the protrusion 45 are arranged on the outer peripheral surface 46 on both sides of the protrusion 45 in the axial direction Z and on both sides of the outer peripheral surface 46 on both sides of the protrusion 45 in the width direction X. As a result, the magnetic flux collecting yoke assembly 40 is attached in a state where it is positioned relative to the housing 20 in both the axial direction Z and the width direction X. Therefore, the magnetic flux collecting yoke 55 arranged inside the sensor housing 41 is positioned relative to the stator 60 attached to the first pinion gear 88a in both the axial direction Z and the width direction X.

[0118] As a result, the distance between the magnetic flux collecting yoke 55 and the flange portion 61 of the stator 60 in the axial direction Z is close to the distance set during the design of the torque sensor 10, and the relative position of the magnetic flux collecting yoke 55 with respect to the flange portion 61 of the stator 60 in the width direction X is close to the relative position set during the design of the torque sensor 10. Therefore, the torque sensor 10 is able to appropriately detect steering torque with reduced variation in the magnetic flux detected by the magnetic flux collecting yoke 55.

[0119] Furthermore, the sensor housing 41 of the magnetic flux collecting yoke assembly 40 has an inclined connecting portion 48 between the seal member arrangement portion 44 and the protrusion 45. Therefore, when the torque sensor 10 is used in a waterproof configuration, the O-ring 70 can be arranged in the seal member arrangement portion 44 while being guided by the inclined connecting portion 48.

[0120] As described above, in the torque sensor 10 according to the first embodiment, the magnetism collecting yoke assembly 40 is provided with the seal member arrangement portion 44 in which the O-ring 70, which is a seal member, can be arranged, so that when the torque sensor 10 is used in a waterproof configuration, the O-ring 70 is arranged in the seal member arrangement portion 44 and the protruding portion 45 of the magnetism collecting yoke assembly 40 is stored in the storage portion 26 of the housing 20, thereby ensuring sealing between the sensor housing 41 and the housing 20 by the O-ring 70. Furthermore, when the torque sensor 10 is used in a non-waterproof configuration, the O-ring 70 is not arranged in the seal member arrangement portion 44 and the protruding portion 45 of the magnetism collecting yoke assembly 40 is stored in the storage portion 26 of the housing 20, so that a magnetism collecting yoke assembly 40 having the same shape as the magnetism collecting yoke assembly 40 used in the waterproof configuration can also be used in the non-waterproof configuration.

[0121] Furthermore, because an inclined connecting portion 48 is provided between the seal member arrangement portion 44 and the protruding portion 45 of the magnetic flux collecting yoke assembly 40, the O-ring 70 can be placed in the seal member arrangement portion 44 while being guided by the inclined connecting portion 48. At this time, the O-ring 70 is placed in the seal member arrangement portion 44 from the crush rib 47 side through the outside of the crush rib 47, but because the end of the crush rib 47 on the side where the seal member arrangement portion 44 is located is connected to the inclined connecting portion 48, the O-ring 70 can be placed in the seal member arrangement portion 44 without getting caught between the crush rib 47 and the seal member arrangement portion 44. This improves assembly ease when placing the O-ring 70 in the seal member arrangement portion 44.

[0122] Therefore, by using the same magnetism collecting yoke assembly 40 for both the waterproof and non-waterproof versions of the torque sensor 10, an increase in the number of parts can be suppressed, thereby reducing manufacturing costs, and the manufacturing costs can also be reduced by improving the assembling performance of the O-ring 70 and enabling easier assembly work. As a result, both the waterproof and non-waterproof versions can be achieved while suppressing an increase in manufacturing costs.

[0123] In the above-mentioned Patent Document 1, the O-ring used as a sealant has elasticity, and when the cylindrical portion is inserted into the mounting hole of the housing, the O-ring collapses, thereby ensuring sealing. However, there is a possibility of installation errors occurring when attaching the component on which the O-ring is placed to the housing into which the component is inserted. If installation errors occur between these components, there is a possibility that the degree of collapse of the O-ring will vary from component to component. In this way, in a configuration in which waterproofing is ensured by an O-ring, if there are individual differences in the degree of collapse of the O-ring, this can lead to a decrease in the sealing performance of the O-ring depending on the degree of collapse. Therefore, there is room for improvement in the degree of collapse of the O-ring used as a sealant.

[0124] In contrast, in the torque sensor 10 according to the first embodiment, in a configuration in which an O-ring 70 is disposed in the seal member disposing portion 44 for waterproofing, the protrusion 45 of the magnetic flux collecting yoke assembly 40 has, on its outer peripheral surface 46, a plurality of crush ribs 47 that abut against the storage portion inner wall 27, which is the inner wall of the storage portion 26 of the housing 20. Therefore, the protrusion 45 can be stored in the storage portion 26 while being positioned relative to the storage portion 26. Furthermore, the abutment length Lc of the crush ribs 47 with the storage portion inner wall 27 is shorter than the combined length Lp of the protrusion 45 and the inclined connection portion 48. Therefore, the crush ribs 47 can abut against the storage portion inner wall 27 while suppressing deformation of the protrusion 45 due to the crush ribs 47 abutting against the storage portion inner wall 27. This makes it possible to make the O-ring 70, which is arranged as a seal member in the seal member arrangement portion 44 of the magnetic flux collection yoke assembly 40, uniformly crushed, thereby ensuring uniform sealing performance by the O-ring 70 around the entire circumference of the O-ring 70. As a result, the sealing performance by the O-ring 70 can be improved.

[0125] Furthermore, the length Lr of the crush rib 47 from the position of the seal member arrangement portion 44 in the insertion direction of the protrusion 45 into the storage portion 26 of the housing 20 to the end of the crush rib 47 opposite the side where the seal member arrangement portion 44 is located is shorter than the combined length Lp of the protrusion 45 and the inclined connecting portion 48 in the same direction. Therefore, the abutment length Lc of the crush rib 47 with the storage portion inner wall 27 can be made shorter than the combined length Lp of the protrusion 45 and the inclined connecting portion 48. This allows the crush rib 47 to abut against the storage portion inner wall 27 while suppressing deformation of the protrusion 45 due to the crush rib 47 abutting against the storage portion inner wall 27, thereby uniformly crushing the O-ring 70 placed in the seal member arrangement portion 44 of the magnetic flux collecting yoke assembly 40. As a result, the sealing performance of the O-ring 70 can be improved.

[0126] Furthermore, when the torque sensor 10 is used in a waterproof configuration, the O-ring 70 is disposed in the seal member arrangement portion 44 of the magnetic flux collecting yoke assembly 40, and abuts against both the seal member abutment portion 25 of the housing 20 and the seal member arrangement portion 44 of the magnetic flux collecting yoke assembly 40 at a position closer to the entrance of the storage portion 26 in the insertion direction of the protrusion 45 into the storage portion 26. This allows the O-ring 70 to prevent liquids such as water from entering from the outside of the housing 20 toward the inside of the storage portion 26. As a result, the sealing properties of the O-ring 70 can be effectively utilized, and the waterproofness of the torque sensor 10 can be improved when used in a waterproof configuration.

[0127] Furthermore, because the crush ribs 47 are disposed on the outer peripheral surface 46 on both sides of the protrusion 45 in the axial direction Z, the position of the magnetism collecting yoke assembly 40 in the axial direction Z relative to the housing 20 can be attached to the housing 20 with high accuracy. Therefore, the magnetism collecting yoke 55 disposed in the magnetism collecting yoke assembly 40 can be disposed with high positional accuracy in the axial direction Z relative to the stator 60 attached to the first pinion gear 88a. As a result, the magnetism collecting yoke 55 is disposed so that the distance in the axial direction Z from the flange portion 61 of the stator 60 is close to the distance set during the design of the torque sensor 10. As a result, the torque sensor 10 can suppress variation in the magnetic flux detected by the magnetism collecting yoke 55, and can appropriately detect steering torque.

[0128] Furthermore, because the crush ribs 47 are disposed on the outer peripheral surface 46 on both sides of the protrusion 45 in the width direction X, the position of the magnetism collecting yoke assembly 40 relative to the housing 20 in the width direction X can be accurately determined when attached to the housing 20. Therefore, the magnetism collecting yoke 55 disposed in the magnetism collecting yoke assembly 40 can be accurately positioned in the width direction X with respect to the stator 60 attached to the first pinion gear 88a. As a result, the magnetism collecting yoke 55 is positioned in a position in the width direction X relative to the flange portion 61 of the stator 60 that is close to the relative position set during the design of the torque sensor 10, and the overlapping area between the flange portion 61 of the stator 60 and the magnetism collecting yoke 55 can be appropriately sized. As a result, the torque sensor 10 can suppress variations in the magnetic flux detected by the magnetism collecting yoke 55 and appropriately detect steering torque.

[0129] Second Embodiment Next, a torque sensor 10 according to a second embodiment will be described. The same components as those in the first embodiment will be denoted by the same reference numerals, and a description thereof will be omitted. The following description will focus on the differences from the first embodiment.

[0130] 11 is a cross-sectional view of the housing 20 of the torque sensor 10 according to the second embodiment. The housing 20 of the torque sensor 10 according to the second embodiment has a storage section 26 and a seal member abutment section 25, similar to the first embodiment. The storage section 26 differs from the first embodiment in that a storage section inner wall 27, which is the inner wall of the storage section 26, has a tapered section 31 and a flat section 32.

[0131] The tapered portion 31 of the storage section inner wall 27 is inclined with respect to the longitudinal direction Y, and the inclination direction is from the side where the seal member abutment portion 25 is located toward the side where the inner peripheral surface 21 of the housing 20 is located in the longitudinal direction Y, in a direction in which the opening area of ​​the storage section 26 becomes smaller when viewed in the longitudinal direction Y. The flat portion 32 of the storage section inner wall 27 is located on the opposite side of the tapered portion 31 from the side where the seal member abutment portion 25 is located in the longitudinal direction Y, and is an inner wall formed parallel to the longitudinal direction Y.

[0132] 12 is a plan view of the magnetic flux collecting yoke assembly 40 included in the torque sensor 10 according to the second embodiment. The magnetic flux collecting yoke assembly 40 included in the torque sensor 10 according to the second embodiment has a sensor housing 41, similar to that of the first embodiment. The sensor housing 41 has a flange portion 42, a connector portion 43, a seal member arrangement portion 44, and a protrusion 45.

[0133] Furthermore, a plurality of crush ribs 47 are arranged on the outer peripheral surface 46 of the protruding portion 45. Unlike the first embodiment, in the second embodiment, the crush ribs 47 of the protruding portion 45 are arranged from the position of the inclined connection portion 48 in the longitudinal direction Y to the position of the end portion 45 a of the protruding portion 45 on the side opposite to the side where the seal member arrangement portion 44 is located in the longitudinal direction Y.

[0134] Here, the end 45a of the protrusion 45 is formed to have a curved shape, as in the first embodiment. Therefore, the distance from the inclined connecting portion 48 to the end 45a of the protrusion 45 in the longitudinal direction Y varies depending on the position in the width direction X, but the crush ribs 47 are arranged from the position of the seal member arrangement portion 44 to the position of the end 45a of the protrusion 45, regardless of their position in the width direction X. Therefore, the length Lr in the longitudinal direction Y of the multiple crush ribs 47 arranged on the outer peripheral surface 46 of the protrusion 45 varies depending on their position in the width direction X.

[0135] 13 is a schematic diagram showing a state in which the protrusion 45 of the magnetic flux collecting yoke assembly 40 is stored in the storage section 26 of the housing 20 in the second embodiment. When attaching the magnetic flux collecting yoke assembly 40 to the housing 20, as in the first embodiment, the protrusion 45 of the sensor housing 41 of the magnetic flux collecting yoke assembly 40 is inserted into the storage section 26 in an orientation that causes the protrusion 45 to protrude from the flange portion 42 toward the side of the housing 20 where the storage section 26 is located in the longitudinal direction Y. When the protrusion 45 of the sensor housing 41 is stored in the storage section 26 of the housing 20, the multiple crush ribs 47 arranged on the outer circumferential surface 46 of the protrusion 45 each abut against the storage section inner wall 27, which is the inner wall of the storage section 26.

[0136] In the second embodiment, the storage section inner wall 27 of the storage section 26 has a tapered portion 31 that is inclined with respect to the longitudinal direction Y and a flat portion 32 that is formed parallel to the longitudinal direction Y. When the protrusion 45 of the sensor housing 41 is stored in the storage section 26, the tapered portion 31 that is inclined with respect to the longitudinal direction Y is inclined in a direction in which the distance between the storage section inner wall 27 and the outer peripheral surface 46 of the protrusion 45 decreases from the opening side of the storage section 26 toward the back side in the insertion direction when the protrusion 45 is inserted into the storage section 26. In other words, the tapered portion 31 of the storage section inner wall 27 is a tapered inner wall in which the distance between the storage section inner wall 27 and the outer peripheral surface 46 of the protrusion 45 decreases from the side where the seal member abutment portion 25 is located toward the side where the inner peripheral surface 21 (see FIG. 11 ) of the housing 20 is located in the longitudinal direction Y.

[0137] The flat portion 32 is located further back than the tapered portion 31 in the insertion direction when inserting the protrusion 45 into the storage portion 26; that is, the flat portion 32 is located on the side of the tapered portion 31 in the longitudinal direction Y where the inner surface 21 of the housing 20 (see Figure 11) is located.

[0138] Furthermore, since the flat portion 32 is formed parallel to the longitudinal direction Y, when the protruding portion 45 of the sensor housing 41 is stored in the storage portion 26, the distance between the storage portion inner wall 27 of the storage portion 26 and the outer peripheral surface 46 of the protruding portion 45 is constant. That is, the flat portion 32 is formed as an inner wall that is approximately parallel to the outer peripheral surface 46 of the protruding portion 45, with the distance between the flat portion 32 and the outer peripheral surface 46 of the protruding portion 45 being constant.

[0139] In this way, the distance between the flat portion 32 formed parallel to the outer peripheral surface 46 of the protruding portion 45 and the outer peripheral surface 46 of the protruding portion 45 is approximately the same as the height of the crush rib 47 from the outer peripheral surface 46 of the protruding portion 45, and is slightly smaller than the height of the crush rib 47. Therefore, when the protruding portion 45 of the sensor housing 41 is stored in the storage portion 26, the crush rib 47 arranged on the outer peripheral surface 46 of the protruding portion 45 abuts against the storage portion inner wall 27 at the flat portion 32.

[0140] For this reason, in the second embodiment, the contact length Lc of the crush rib 47 with the storage section inner wall 27 is the length in the longitudinal direction Y of the flat portion 32 of the storage section inner wall 27. Because the flat portion 32 of the storage section inner wall 27 is a part of the storage section inner wall 27 in the longitudinal direction Y, the contact length Lc of the crush rib 47 with the storage section inner wall 27, which is the contact length between the crush rib 47 and the flat portion 32, is shorter than the combined length Lp of the protrusion 45 and the inclined connection portion 48 of the sensor housing 41.

[0141] In the second embodiment, too, the crush rib 47 disposed on the protruding portion 45 of the magnetic flux collecting yoke assembly 40 has a contact length Lc in the longitudinal direction Y with the storage section inner wall 27 of the housing 20 that is shorter than the combined length Lp of the protruding portion 45 and the inclined connecting portion 48 in the longitudinal direction Y. This makes it possible to reduce the range of deformation of the protruding portion 45 when the crush rib 47 abuts against the storage section inner wall 27, thereby suppressing deformation of the seal member arrangement portion 44 that is caused by deformation of the protruding portion 45 due to the crush rib 47 abutting against the storage section inner wall 27. This makes it possible to uniformly crush the O-ring 70 disposed between the seal member arrangement portion 44 of the magnetic flux collecting yoke assembly 40 and the seal member abutment portion 25 of the housing 20, thereby ensuring uniform sealing performance by the O-ring 70 around the entire circumference of the O-ring 70.

[0142] Furthermore, in the second embodiment, the storage section inner wall 27 of the storage section 26 of the housing 20 has a tapered portion 31 and a flat portion 32 located further back than the tapered portion 31 in the insertion direction of the protrusion 45 into the storage section 26, and the crush ribs 47 arranged on the outer peripheral surfaces 46 of the protrusions 45 abut against the storage section inner wall 27 at the flat portions 32. As a result, the crush ribs 47 abut against the storage section inner wall 27 at a position away from the seal member arrangement portion 44. Therefore, even if the protrusions 45 are deformed due to the crush ribs 47 abutting against the storage section inner wall 27, the deformation of the protrusions 45 is less likely to affect the seal member arrangement portion 44. Therefore, deformation of the seal member arrangement portion 44 caused by deformation of the protrusions 45 due to the crush ribs 47 abutting against the storage section inner wall 27 can be more reliably suppressed, and the O-ring 70 arranged in the seal member arrangement portion 44 of the magnetic flux collecting yoke assembly 40 can be crushed uniformly. As a result, the sealing performance of the O-ring 70 can be improved.

[0143] Furthermore, because the storage section inner wall 27 has the tapered portion 31 closer to the seal member abutment portion 25 than the flat portion 32, the protrusion 45 of the magnetic flux collecting yoke assembly 40 can be easily inserted into the storage section 26 of the housing 20. In other words, when inserting the protrusion 45 into the storage section 26, the crush ribs 47 arranged on the outer peripheral surface 46 of the protrusion 45 can be press-fit into the flat portion 32 while being guided by the tapered portion 31. This improves the ease of assembling the magnetic flux collecting yoke assembly 40 to the housing 20 when the crush ribs 47 are provided on the protrusion 45 to position the magnetic flux collecting yoke assembly 40 relative to the housing 20. As a result, the torque sensor 10 can be assembled more easily.

[0144] [Variation] In the second embodiment described above, the storage section inner wall 27 of the storage section 26 has a tapered portion 31 and a flat portion 32, so that the crush rib 47 arranged on the protrusion 45 of the magnetic flux collecting yoke assembly 40 abuts against a portion of the storage section inner wall 27 in the longitudinal direction Y. However, the storage section inner wall 27 may have portions other than the tapered portion 31 and the flat portion 32.

[0145] 14 is a schematic diagram illustrating a modified example of the torque sensor 10 according to the second embodiment, in which the storage section inner wall 27 has an expanded diameter portion 36 and a reduced diameter portion 37. For example, as shown in FIG. 14 , the storage section inner wall 27 of the storage section 26 of the housing 20 may have the expanded diameter portion 36 and the reduced diameter portion 37 that are at different distances from the outer circumferential surface 46 of the protrusion 45. In this case, the expanded diameter portion 36 of the storage section inner wall 27 is located on the opening side of the storage section 26 relative to the reduced diameter portion 37 in the insertion direction of the protrusion 45 into the storage section 26, and is formed apart from and parallel to the outer circumferential surface 46 of the protrusion 45. In other words, the expanded diameter portion 36 is located on the side of the reduced diameter portion 37 where the seal member abutment portion 25 is located in the longitudinal direction Y.

[0146] Furthermore, the reduced diameter portion 37 of the storage section inner wall 27 is located further back than the expanded diameter portion 36 in the insertion direction of the protrusion 45 into the storage section 26, and is formed so that the distance from the outer circumferential surface 46 of the protrusion 45 is smaller than the distance between the expanded diameter portion 36 and the outer circumferential surface 46 of the protrusion 45. In other words, the reduced diameter portion 37 is arranged on the side of the expanded diameter portion 36 where the inner circumferential surface 21 of the housing 20 (see FIG. 11 ) is located in the longitudinal direction Y, and is formed parallel to the outer circumferential surface 46 of the protrusion 45 at a distance smaller than the distance between the expanded diameter portion 36 and the outer circumferential surface 46 of the protrusion 45.

[0147] As described above, a step portion 35 is formed between the expanded diameter portion 36 and the reduced diameter portion 37, which are at different distances from the outer circumferential surface 46 of the protrusion 45, and the expanded diameter portion 36 and the reduced diameter portion 37 of the storage section inner wall 27 are connected by the step portion 35. The crush rib 47 abuts against the storage section inner wall 27, which has the expanded diameter portion 36 and the reduced diameter portion 37, at the reduced diameter portion 37. Therefore, the abutment length Lc of the crush rib 47 with the storage section inner wall 27 is the length in the longitudinal direction Y of the reduced diameter portion 37 of the storage section inner wall 27. Because the reduced diameter portion 37 of the storage section inner wall 27 is a part of the storage section inner wall 27 in the longitudinal direction Y, the abutment length Lc of the crush rib 47 with the storage section inner wall 27, which is the abutment length between the crush rib 47 and the reduced diameter portion 37, is shorter than the combined length Lp of the protrusion 45 and the inclined connection portion 48 of the sensor housing 41.

[0148] The storage section inner wall 27 having the expanded diameter portion 36 and the reduced diameter portion 37 is formed, for example, by cutting the storage section inner wall 27. In other words, the storage section 26 having the flat storage section inner wall 27 is formed by casting, and then the expanded diameter portion 36 is formed by cutting the portion of the storage section inner wall 27 near the seal member abutment portion 25. In this way, the storage section inner wall 27 is formed having the expanded diameter portion 36 and the reduced diameter portion 37 that are at different distances from the protrusion 45 of the magnetic flux collecting yoke assembly 40.

[0149] In this way, the storage section inner wall 27 of the storage section 26 of the housing 20 has the expanded diameter portion 36 and the reduced diameter portion 37, and the crush rib 47 arranged on the outer peripheral surface 46 of the protrusion 45 abuts against the storage section inner wall 27 at the reduced diameter portion 37, allowing the crush rib 47 to abut against the storage section inner wall 27 at a position away from the seal member arrangement portion 44. Therefore, even if the protrusion 45 is deformed due to the crush rib 47 abutting against the storage section inner wall 27, the deformation of the protrusion 45 is less likely to affect the seal member arrangement portion 44, and deformation of the seal member arrangement portion 44 due to the deformation of the protrusion 45 can be more reliably suppressed. This allows the O-ring 70 arranged in the seal member arrangement portion 44 of the magnetic flux collecting yoke assembly 40 to be crushed uniformly. As a result, the sealing performance of the O-ring 70 can be improved.

[0150] Furthermore, by cutting the flat storage section inner wall 27 to form the expanded diameter portion 36, it is possible to easily form the storage section inner wall 27 having the expanded diameter portion 36 and the reduced diameter portion 37 that are at different distances from the outer peripheral surface 46 of the protrusion 45 of the sensor housing 41 of the magnetic flux collecting yoke assembly 40. This makes it possible to easily form the storage section inner wall 27 in which the abutment length Lc between the crush ribs 47 arranged on the outer peripheral surface 46 of the protrusion 45 and the storage section inner wall 27 can be made shorter than the length Lp of the protrusion 45. As a result, it is possible to easily improve the sealing performance of the O-ring 70.

[0151] In the first embodiment described above, the crush ribs 47 of the protruding portion 45 of the magnetic flux collecting yoke assembly 40 are arranged at six locations on the outer peripheral surface 46 of the protruding portion 45, but the number of crush ribs 47 may be other than this. The number of crush ribs 47 is not important as long as they can be appropriately positioned when storing the protruding portion 45 in the storage portion 26 of the housing 20.

[0152] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. The configurations described as the embodiments and modified examples may be combined as appropriate.

[0153] REFERENCE SIGNS LIST 10 Torque sensor 20 Housing 21 Inner peripheral surface 25 Seal member abutment portion 26 Storage portion 27 Storage portion inner wall 31 Tapered portion 32 Flat portion 35 Step portion 36 Expanded diameter portion 37 Reduced diameter portion 40 Magnet collection yoke assembly 41 Sensor housing 42 Flange portion 43 Connector portion 44 Seal member arrangement portion 45 Protrusion 45a End portion 46 Outer peripheral surface 47 Crush rib 48 Inclined connection portion 50 Hall IC 51 Lead frame 52 Circuit board 55 Magnet collection yoke 60 Stator 65 Magnet 70 O-ring 80 Steering device 81 Steering wheel 82 Steering shaft 84 Universal joint 85 Intermediate shaft 86 Universal joint 87 Stub shaft 87a Torsion bar 88 Steering gear 88a First pinion gear 88b Rack bar 88c Second pinion gear 89 Tie rod 100 ECU 101 Vehicle speed sensor 102 Electric motor 103 Ignition switch 104 Power supply device

Claims

1. A torque sensor comprising: a housing; and a magnetic flux collecting yoke assembly disposed inside the housing and detachably attached to the housing; wherein the housing has a storage section for storing the magnetic flux collecting yoke assembly; the magnetic flux collecting yoke assembly has a seal member arrangement section in which a seal member can be arranged, and a protrusion stored inside the storage section; the protrusion has a plurality of crush ribs on its outer peripheral surface that abut against an inner wall of the storage section that is the inner wall of the storage section; the protrusion has a stepped portion relative to the seal member arrangement section because its outline shape when viewed in the direction of insertion of the protrusion into the storage section is smaller than the outline shape of the seal member arrangement section; and between the seal member arrangement section and the protrusion is provided an inclined connection section that is inclined with respect to the insertion direction and connects the seal member arrangement section and the protrusion; the crush rib has an end on the side where the seal member arrangement section is located in the insertion direction connected to the inclined connection section, and abuts against the inner wall of the storage section at a length that is shorter than the combined length of the protrusion and the inclined connection section in the insertion direction.

2. A torque sensor as described in claim 1, wherein the length of the crush rib from the position of the seal member arrangement portion in the insertion direction to the end opposite the side on which the seal member arrangement portion is located is shorter than the combined length of the protrusion and the inclined connection portion in the insertion direction.

3. A torque sensor as described in claim 1, which has a magnet attached to one of two shafts connected via a torsion bar and a stator attached to the other shaft, and the crush ribs are arranged on the outer peripheral surface on both sides of the protrusion in the axial direction of the shaft.

4. A torque sensor as described in claim 1, which has a magnet attached to one of two shafts connected via a torsion bar and a stator attached to the other shaft, and the crush ribs are arranged on the outer peripheral surface on both sides of the protrusion in a direction perpendicular to both the axial direction of the shaft and the insertion direction.

5. A torque sensor as described in claim 1, wherein the inner wall of the storage section has a tapered section in which the distance between the inner wall of the storage section and the outer peripheral surface of the protrusion decreases as the wall moves from the opening side of the storage section toward the rear in the insertion direction, and a flat section located further rear than the tapered section in the insertion direction and in which the distance between the inner wall of the storage section and the outer peripheral surface of the protrusion is constant, and the crush rib abuts against the inner wall of the storage section at the flat section.

6. A torque sensor as described in claim 1, wherein the inner wall of the storage section has an expanded diameter section located on the opening side of the storage section in the insertion direction and spaced apart from the outer peripheral surface of the protrusion, and a reduced diameter section located further back than the expanded diameter section in the insertion direction and whose distance from the outer peripheral surface of the protrusion is smaller than the distance between the expanded diameter section and the outer peripheral surface of the protrusion, and wherein the crush rib abuts against the inner wall of the storage section at the reduced diameter section.

7. A torque sensor as described in claim 1, wherein the housing has a seal member abutment portion where the seal member abuts against the inner peripheral surface, located closer to the entrance than the storage portion in the insertion direction, and the seal member is arranged in the seal member arrangement portion and abuts against both the seal member arrangement portion and the seal member abutment portion at a position closer to the entrance than the storage portion in the insertion direction.

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