Torque sensor

Abstract

A torque sensor 10 comprises: a stub shaft 86; a first pinion gear 91 through which torque is transmitted to and from the stub shaft 86 via a torsion bar 95; a sensor body 58 fixed to the first pinion gear 91 or the stub shaft 86; a sensor housing 21 that houses the stub shaft 86 and the sensor body 58; and a bearing 70 that rotatably supports the stub shaft 86 with respect to the sensor housing 21. The stub shaft 86 has a guide part 87 having a diameter that is slightly smaller than the diameter of a portion of the stub shaft 86 where the bearing 70 is disposed. The length L1 in the axial direction from a guide end 87a to an end section 58a of the sensor body 58 on a side where the guide part 87 is located is longer than the length L2 in the axial direction from the bearing 70 to an end section 23 of the sensor housing 21.

Description

Torque sensor

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

[0002] An example of a torque sensor for detecting the torque applied to a rotating body of a steering device is one that detects torque by detecting a change in magnetism. For example, the torque detection sensor described in Patent Document 1 includes a permanent magnet fixed to an input shaft, a stator fixed to a handle-side pinion shaft that is an output shaft, a collector that collects the magnetic flux guided by the stator, and a magnetic sensor that converts the magnetic flux guided by the collector into an electrical signal corresponding to the magnetic flux density. These members constituting the torque detection sensor are housed in a sensor housing, which is a housing that houses the torque detection sensor inside.

[0003] Japanese Unexamined Patent Application Publication No. 2017-171071

[0004] Here, in order to suppress the enlargement around the torque sensor, it is preferable to make the clearance with the members arranged inside the sensor housing as small as possible for the sensor housing that covers the torque sensor. However, if the clearance between the members arranged inside the sensor housing and the sensor housing is made too small, there is a possibility that these members and the sensor housing will interfere when assembling the sensor housing.

[0005] For example, when a through hole through which the input shaft passes is formed in the sensor housing and the sensor housing is assembled by passing the input shaft through the through hole, when the sensor housing tilts due to play during assembly of the sensor housing, there is a possibility that the members constituting the torque sensor and the sensor housing will interfere. For this reason, it has been extremely difficult to miniaturize the sensor housing without the sensor housing interfering with the members constituting the torque sensor when assembling the sensor housing.

[0006] The present disclosure has been made in view of the above, and an object thereof is to provide a torque sensor capable of miniaturizing the sensor housing while suppressing interference between the members constituting the torque sensor and the sensor housing.

[0007] The torque sensor of this disclosure comprises an input shaft, an output shaft to which torque is transmitted via a torsion bar to the input shaft, a sensor body fixed to the output shaft or the input shaft, a sensor housing housing the input shaft and the sensor body, and a bearing that rotatably supports the input shaft with respect to the sensor housing, wherein the input shaft has a guide portion on the side of the input shaft opposite to the side of the input shaft where the sensor body is located, in the axial direction of the input shaft with respect to the portion where the bearing is located, the guide portion having a diameter slightly smaller than the diameter of the portion of the input shaft where the bearing is located, and the axial length from the end of the guide portion on the side of the sensor body where the guide portion is located to the end of the sensor body where the guide portion is located to the end of the bearing where the sensor body is located to the end of the sensor housing on the side of the bearing where the sensor body is located in the axial direction is longer than the axial length from the end of the bearing where the sensor body is located to the end of the sensor housing where the sensor body is located with respect to the bearing.

[0008] In this configuration, the length from the end of the guide portion of the input shaft to the end of the sensor body on the side where the guide portion is located is longer than the length from the bearing fitted into the sensor housing to the end of the sensor housing on the side where the sensor body is located relative to the bearing. Therefore, when passing the input shaft through the bearing fitted into the sensor housing in order to assemble the sensor housing onto the input shaft, if the part of the input shaft opposite to the side where the sensor body is located relative to the guide portion is passing through the bearing, the sensor housing can be prevented from reaching the position of the sensor body to be attached to the output shaft or input shaft. As a result, even if the sensor housing tilts significantly relative to the input shaft due to play between the bearing and the input shaft when the part of the input shaft opposite to the side where the sensor body is located relative to the guide portion is passing inside the bearing fitted into the sensor housing, it is possible to suppress the sensor housing from contacting the sensor body. Therefore, even when the sensor housing is miniaturized, it is possible to suppress the sensor housing from contacting the sensor body when assembling the sensor housing onto the input shaft. As a result, it is possible to miniaturize the sensor housing while suppressing interference between the sensor body and the sensor housing, which are components of the torque sensor.

[0009] In a desirable configuration, the maximum diameter of the sensor body is D1, the inner circumferential surface of the sensor housing is formed to be circular, the diameter of the inner circumferential surface of the sensor housing is D2, the axial length from the end of the bearing on the side where the sensor body is located to the end of the sensor housing on the side where the sensor body is located relative to the bearing is L2, and the angle of inclination of the sensor housing with respect to the axial direction when the bearing fitted inside the sensor housing is located on the guide portion of the input shaft is θ, such that 2 × L2 tanθ < D2 - D1 is satisfied.

[0010] With this configuration, the relationship between the maximum diameter D1 of the sensor body, the diameter D2 of the inner surface of the sensor housing, the length L2 from the bearing to the end of the sensor housing on the side where the sensor body is positioned relative to the bearing that fits into the sensor housing, and the angle θ of the tilt of the sensor housing when the bearing that fits into the sensor housing is positioned on the guide portion of the input shaft satisfies 2 × L2 tan θ < D2 - D1. Therefore, when the sensor housing is tilted with the bearing that fits into the sensor housing positioned on the guide portion of the input shaft, it is possible to suppress the sensor housing from contacting the sensor body. As a result, interference between the sensor body and the sensor housing can be suppressed while the size of the sensor housing can be reduced.

[0011] In a preferred configuration, the bearing has an outer ring and an inner ring, the outer ring is fitted into the sensor housing, and the guide portion of the input shaft and the inner ring are slidable against each other when the input shaft is housed inside the sensor housing.

[0012] In this configuration, the outer ring of the bearing fits into the sensor housing, and the guide portion of the input shaft and the inner ring of the bearing can slide against each other when the input shaft is housed inside the sensor housing. This prevents the sensor housing from tilting too much and contacting the stator, while ensuring ease of assembly of the sensor housing to the input shaft. As a result, interference between the stator and the sensor housing is suppressed, the ease of assembly of the torque sensor is improved, and manufacturing costs can be reduced.

[0013] In a preferred configuration, the sensor housing has a bearing fitting portion on one end in the axial direction into which the bearing is fitted, and an opening end on the other end in the axial direction which is an end that opens in the axial direction, the sensor body is positioned between the bearing fitting portion and the opening end of the sensor housing in the axial direction, and the size of the inner circumferential surface of the portion housing the sensor body in the direction perpendicular to the axial direction increases from the side where the bearing fitting portion is located to the side where the opening end is located in the axial direction.

[0014] With this configuration, the size of the inner circumferential surface of the part of the sensor housing that houses the sensor body increases in the direction perpendicular to the axial direction as it moves from the side where the bearing fitting part is located to the side where the opening end is located. Therefore, when the sensor housing is tilted with the bearing fitted into the sensor housing positioned on the guide part of the input shaft, the sensor housing is less likely to come into contact with the sensor body. As a result, interference between the sensor body and the sensor housing can be suppressed while the sensor housing can be made smaller.

[0015] The torque sensor according to this disclosure has the effect of miniaturizing the sensor housing while suppressing interference between the components constituting the torque sensor and the sensor housing.

[0016] Figure 1 is a schematic diagram illustrating a steering device according to the first embodiment. Figure 2 is a cross-sectional view of the steering device according to the first embodiment, including the torque sensor. Figure 3 is a schematic diagram illustrating the outline of the magnet, stator, and magnetic collection yoke of the torque sensor. Figure 4 is a schematic diagram showing the relationship between the length of the guide portion of the stub shaft and the sensor housing in the axial direction. Figure 5 is a schematic diagram showing the state in which the stub shaft begins to pass inside the sensor housing shown in Figure 4. Figure 6 is an explanatory diagram of the size of the inner circumferential surface of the sensor housing. Figure 7 is an explanatory diagram of the inclination of the sensor housing when the bearing fitted into the sensor housing is located on the guide portion of the stub shaft. Figure 8 is a detailed view of the main part of the sensor housing shown in Figure 2. Figure 9 is a side view of the torque sensor according to the second embodiment. Figure 10 is a perspective view of the magnetic collection yoke assembly and sensor body in the torque sensor according to the second embodiment. Figure 11 is a view taken along the line A-A in Figure 9. Figure 12 is a cross-sectional view of the main part of the torque sensor according to the third embodiment. Figure 13 is a cross-sectional view of the main part of the torque sensor at a different position than that shown in Figure 12. Figure 14 is a perspective view of the torque sensor according to the third embodiment.

[0017] The present disclosure will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the embodiments described below. Furthermore, the components in the embodiments below include those easily conceivable by those skilled in the art, those substantially identical, and those within the scope of equivalents. Moreover, the components disclosed in the embodiments below can be combined as appropriate.

[0018] [First Embodiment] Figure 1 is a schematic diagram illustrating a steering device 80 according to the first embodiment. As shown in Figure 1, the steering device 80 includes a steering wheel 81, a steering shaft 82, a universal joint 83, an intermediate shaft 84, a universal joint 85, a stub shaft 86, a steering gear 90, and a tie rod 98, in the order in which the force applied by the operator is transmitted. The steering device 80 also includes a control device (hereinafter referred to as ECU (Electronic Control Unit)) 100, a torque sensor 10, and an electric motor 102. The vehicle speed sensor 101 is installed in the vehicle and outputs a vehicle speed signal V to the ECU 100 via CAN (Controller Area Network) communication.

[0019] The steering shaft 82 is connected to the steering wheel 81 at one end and to the universal joint 83 at the other end.

[0020] The intermediate shaft 84 is connected to a universal joint 83 at one end and to a universal joint 85 at the other end. The stub shaft 86 is connected to a universal joint 85 at one end and to a torque sensor 10 at the other end. The torque sensor 10 is positioned between the stub shaft 86 and the first pinion gear 91 of the steering gear 90 and detects the torque transmitted between the stub shaft 86 and the first pinion gear 91.

[0021] More specifically, the first pinion gear 91 is a shaft-shaped member in which a gear (not shown) that meshes with a rack bar 93 (described later) is formed at the end opposite to the side connected to the stub shaft 86. The stub shaft 86 and the first pinion gear 91 are connected via a torsion bar 95 (see Figure 2). One end of the torsion bar 95 is connected to the stub shaft 86, and the other end is connected to the first pinion gear 91. Rotational torque is transmitted between the stub shaft 86 and the first pinion gear 91 via the torsion bar 95, which is connected to both in this way.

[0022] The torque sensor 10 is a torque detection device that detects the torque acting on the shaft connected to the torque sensor 10, and detects the rotational torque transmitted between the stub shaft 86 and the first pinion gear 91 via the torsion bar 95. In other words, the stub shaft 86 and the first pinion gear 91 connected via the torsion bar 95 are the shafts that are detected when the torque sensor 10 detects torque.

[0023] The steering gear 90 comprises a first pinion gear 91, a rack bar 93, and a second pinion gear 94. The first pinion gear 91 is connected to the stub shaft 86 via a torsion bar 95. The rack bar 93 has rack teeth (not shown) that mesh with the gears of the first pinion gear 91. The rack bar 93 also meshes with the second pinion gear 94 at a different position from the first pinion gear 91.

[0024] An electric motor 102 is connected to the second pinion gear 94 via a worm gear reduction device (not shown), and the second pinion gear 94 is rotatable by the driving force transmitted from the electric motor 102. The electric motor 102 rotates the second pinion gear 94 via a worm gear reduction device (not shown). The electric motor 102 is, for example, a brushless motor, but it may also be a motor equipped with brushes (sliders) and a commutator (commutator).

[0025] The steering gear 90 converts the rotational motion transmitted to the first pinion gear 91 and the second pinion gear 94 into straight-line motion using a rack bar 93 located inside a rack housing (not shown). The steering device 80 according to the first embodiment is a dual pinion assist system in which the rack bar 93 performs straight-line motion by the rotational motion transmitted from the first pinion gear 91 and the second pinion gear 94. The tie rod 98 is connected to the rack bar 93. In other words, the steering device 80 is a rack and pinion type electric power steering device.

[0026] The torque sensor 10 detects the steering force of the driver transmitted to the steering shaft 82 via the steering wheel 81 as steering torque. The vehicle speed sensor 101 detects the driving speed (vehicle speed) of the vehicle on which the steering device 80 is installed. The electric motor 102, the torque sensor 10, and the vehicle speed sensor 101 are electrically connected to the ECU 100.

[0027] 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. Specifically, 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 the power supply device (e.g., the onboard battery) 104. The ECU 100 calculates an auxiliary steering command value for the assist command based on the steering torque T and the vehicle speed signal V. Then, the ECU 100 adjusts the power value E supplied to the electric motor 102 based on the calculated auxiliary steering command value. The ECU 100 acquires information on the induced voltage from the electric motor 102 or information output from a rotation detection device such as a resolver provided on the electric motor 102 as operation information M.

[0028] The steering force input by the operator (driver) to the steering wheel 81 is transmitted to the first pinion gear 91. The steering force transmitted to the first pinion gear 91 is then transmitted to the tie rod 98 via the steering gear 90, causing the wheel to displace.

[0029] Furthermore, the steering force input by the operator to the steering wheel 81 is transmitted to the torque sensor 10, which is located in the steering force transmission path from the steering wheel 81 to the first pinion gear 91. At this time, 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. The ECU 100 then 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 94.

[0030] The auxiliary steering torque transmitted to the second pinion gear 94 is transmitted to the tie rod 98 via the steering gear 90, displacing the wheel. In other words, the steering device 80 displaces the wheel using not only the steering force of the operator transmitted to the rack bar 93 via the first pinion gear 91, but also the auxiliary steering torque of the electric motor 102 transmitted to the rack bar 93 via the second pinion gear 94.

[0031] Figure 2 is a cross-sectional view of the steering device 80 according to the first embodiment, including the torque sensor 10. In the following description, the axial direction of the stub shaft 86 and the first pinion gear 91 on which the torque sensor 10 is located will also be described as the axial direction in the torque sensor 10. Similarly, the circumferential direction centered on the axis of the stub shaft 86 and the first pinion gear 91 will also be described as the circumferential direction in the torque sensor 10, and the radial direction centered on the axis of the stub shaft 86 and the first pinion gear 91 will also be described as the radial direction in the torque sensor 10.

[0032] A housing 20 is positioned around the portion of the stub shaft 86 and the first pinion gear 91 that are connected via a torsion bar 95. The housing 20 has a sensor housing 21 and a second housing 31 that are connected to each other. The sensor housing 21 is positioned closer to the stub shaft 86 in the axial direction and mainly covers the stub shaft 86, while the second housing 31 is positioned closer to the first pinion gear 91 in the axial direction and mainly covers the first pinion gear 91. In other words, at least a portion of the stub shaft 86 and the first pinion gear 91 are positioned inside the sensor housing 21 and the second housing 31, with at least a portion of the stub shaft 86 positioned inside the sensor housing 21 and at least a portion of the first pinion gear 91 positioned inside the second housing 31. The sensor housing 21 is attached to the second housing 31 by mounting bolts (not shown), thereby fixing the sensor housing 21 to the second housing 31.

[0033] Furthermore, a bearing 70 is positioned inside the sensor housing 21, between the stub shaft 86 and the sensor housing 21. The sensor housing 21 has a bearing fitting portion 22 on one end of the sensor housing 21 in the axial direction, into which the bearing 70 fits. The bearing fitting portion 22 is formed with an inner diameter approximately the same as the outer diameter of the bearing 70. The bearing 70 is positioned inside the sensor housing 21 by fitting into the sensor housing 21 at the bearing fitting portion 22.

[0034] Furthermore, the stub shaft 86 has a fitting portion 86a in which the bearing 70 is fitted at the position where the bearing 70 is to be placed on the stub shaft 86. The fitting portion 86a has a diameter approximately the same as the inner diameter of the bearing 70, and its width in the axial direction is approximately the same as the width of the bearing 70 in the axial direction.

[0035] The stub shaft 86 is rotatably supported by the sensor housing 21 via a bearing 70 positioned between it and the sensor housing 21. Specifically, the bearing 70 has an outer ring 71 and an inner ring 72, with the outer ring 71 fitting into the bearing fitting portion 22 of the sensor housing 21 and the inner ring 72 fitting into the fitting portion 86a of the stub shaft 86. With the bearing 70 interposed between the stub shaft 86 and the sensor housing 21 in this way, the stub shaft 86 is rotatably supported by the bearing 70 relative to the sensor housing 21.

[0036] Furthermore, a bearing 74 is positioned inside the second housing 31, and the bearing 74 is positioned between the first pinion gear 91 and the second housing 31. The first pinion gear 91 is rotatably supported by the second housing 31 via the bearing 74 positioned between it and the second housing 31. In other words, the bearing 74 has an outer ring 75 and an inner ring 76, with the outer ring 75 fitted into the second housing 31 and the inner ring 76 fitted into the first pinion gear 91. With the bearing 74 interposed between the first pinion gear 91 and the second housing 31 in this way, the first pinion gear 91 is rotatably supported by the bearing 74 relative to the second housing 31.

[0037] The stub shaft 86 is rotatably supported by the sensor housing 21, and the first pinion gear 91 is rotatably supported by the second housing 31. Therefore, the stub shaft 86 and the first pinion gear 91, which are connected via the torsion bar 95, are rotatably supported together by the sensor housing 21 and the second housing 31.

[0038] The housing 20 is mounted to the vehicle body in a non-rotatable state, and the housing 20 rotatably supports the stub shaft 86 and the first pinion gear 91 through bearings 70 located in the sensor housing 21 and bearings 74 located in the second housing 31.

[0039] Furthermore, a sealing member 78 is positioned between the stub shaft 86 and the sensor housing 21. The sealing member 78 is positioned between the stub shaft 86 and the sensor housing 21 at a location opposite to the side of the bearing 70 where the first pinion gear 91 is located in the axial direction. In the first embodiment, the steering device 80 is positioned with the side where the stub shaft 86 is located facing upwards and the side where the first pinion gear 91 is located facing downwards. Therefore, the sealing member 78 is positioned near the upper end of the sensor housing 21, which prevents water or the like from entering the sensor housing 21 from the upper side.

[0040] The torque sensor 10 is located inside the sensor housing 21 and is positioned near the ends of the stub shaft 86, which is the input shaft, and the first pinion gear 91, which is the output shaft connected to the stub shaft 86 via a torsion bar 95. Both the stub shaft 86 and the first pinion gear 91 are shafts that have a hollow portion, and the end of one shaft extends inward from the end of the other shaft. In the first embodiment, the stub shaft 86 extends inward from the first pinion gear 91.

[0041] The torsion bar 95 is positioned from the inside of the stub shaft 86 to the inside of the first pinion gear 91, with one end connected to the stub shaft 86 and the other end connected to the first pinion gear 91. In other words, the stub shaft 86 and the first pinion gear 91 are not directly connected, but are connected via the torsion bar 95, which is an axial member. As a result, the stub shaft 86 and the first pinion gear 91 can rotate relative to each other, and when a slight twist occurs in the torsion bar 95, the stub shaft 86 and the first pinion gear 91 rotate relative to each other in accordance with the twist of the torsion bar 95.

[0042] The torque sensor 10 is positioned near the end of the stub shaft 86 and the first pinion gear 91, which are connected via the torsion bar 95 as shown above. By detecting the angle of relative rotation between the stub shaft 86 and the first pinion gear 91, it is possible to detect the torque acting between the stub shaft 86 and the first pinion gear 91.

[0043] The torque sensor 10 includes a magnet 65, a stator 60, and a magnetic collecting yoke 50 (see Figure 3). The magnet 65 and stator 60 are attached separately to the stub shaft 86 and the first pinion gear 91, respectively. The magnet 65 and stator 60 attached to the stub shaft 86 and the first pinion gear 91 constitute the sensor body 58 of the torque sensor 10. The sensor body 58 is a component that is fixed to the stub shaft 86, which is the input shaft, or the first pinion gear 91, which is the output shaft, in the torque sensor 10. The magnetic collecting yoke 50 is included in the magnetic collecting yoke assembly 40, and the magnetic collecting yoke 50 is fixed to the sensor housing 21 by attaching the magnetic collecting yoke assembly 40 to the sensor housing 21. The torque sensor 10 configured in this way is capable of detecting torque based on the change in magnetism that occurs when the torsion bar 95 is slightly twisted and the stub shaft 86 and the first pinion gear 91 rotate relative to each other.

[0044] FIG. 3 is a schematic diagram for explaining an overview of a magnet 65, a stator 60, and a magnetic flux collecting yoke 50 included in the torque sensor 10. One of the magnet 65 and the stator 60 that constitute the sensor body 58 included in the torque sensor 10 is attached to the input shaft, and the other is attached to the output shaft. In the first embodiment, the magnet 65 is attached to a stub shaft 86 which is an input shaft, and the stator 60 is attached to a first pinion gear 91 which is an output shaft. Among these, the magnet 65 is formed in a substantially cylindrical shape, and is an annular permanent magnet in which a plurality of magnetic poles are alternately arranged in the circumferential direction. That is, the magnet 65 is a multi-pole magnet in which N poles and S poles, which are different magnetic poles, are alternately arranged in the circumferential direction of the magnet 65 formed in an annular shape.

[0045] The stator 60 has a flange portion 61 and a tooth portion 62. The tooth portion 62 is a portion through which magnetic flux from the magnet 65 flows, and the flange portion 61 is a portion that guides the magnetic flux from the magnet 65 flowing from the tooth portion 62 to the stator 60 to the magnetic flux collecting yoke 50.

[0046] The flange portion 61 is formed in an annular plate shape in which the thickness direction is the axial direction. The tooth portion 62 extends from the inner peripheral portion of the annular flange portion 61 in the axial direction of the flange portion 61, and is formed in a plate shape in which the thickness direction of the plate is the radial direction of the flange portion 61. Further, the tooth portion 62 is arranged such that a plurality of tooth portions 62 are arranged side by side in the circumferential direction of the flange portion 61 with a gap therebetween.

[0047] The stator 60 formed in this way has a first stator 60a and a second stator 60b which are a pair of stators formed in the same shape. The first stator 60a and the second stator 60b each have a flange portion 61 and a teeth portion 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 axis in such a direction that the flange portions 61 of both are coaxially located and the flange portion 61 is located in a direction away from the other stator 60. In the first embodiment, both the first stator 60a and the second stator 60b are attached to the first pinion gear 91.

[0048] That is, the first stator 60a is arranged in such a direction that the first teeth portion 62a extends from the first flange portion 61a toward the second stator 60b side, and the second stator 60b is arranged in such a direction that the second teeth portion 62b extends from the second flange portion 61b toward the first stator 60a side. At that time, since a plurality of the first teeth portions 62a and the second teeth portions 62b are provided on the first flange portion 61a and the second flange portion 61b at intervals, the first stator 60a and the second stator 60b are combined so that the teeth portion 62 of its own stator 60 is located at a portion where the teeth portion 62 of the other stator 60 is not located in the circumferential direction.

[0049] The magnet 65 attached to the stub shaft 86 is positioned inside the first stator 60a and the second stator 60b, which are assembled in this manner. Furthermore, the magnet 65 and the stator 60 are positioned so that their axial directions coincide with the axial directions of the stub shaft 86 and the first pinion gear 91. For these reasons, the magnet 65 and the stator 60 are positioned such that the outer surface of the magnet 65 faces the teeth portion 62 of the stator 60 when attached to the stub shaft 86 and the first pinion gear 91. In other words, the stator 60 attached to the first pinion gear 91 has multiple teeth portion 62 through which magnetic flux from the magnet 65 flows in the portion where the axial position of the first pinion gear 91 is the same as that of the magnet 65 attached to the stub shaft 86, and the magnet 65 is positioned facing the multiple teeth portion 62 of the stator 60.

[0050] The magnet 65 and the stator 60 are positioned in this relative position. When torque is transmitted between the stub shaft 86 and the first pinion gear 91 via the torsion bar 95, causing the stub shaft 86 and the first pinion gear 91 to rotate slightly relative to each other, the relative position of the magnet 65 and the stator 60 changes, and consequently, the magnetic flux acting from the magnet 65 to the stator 60 changes.

[0051] Furthermore, a magnetic collecting yoke 50, which is part of the magnetic collecting yoke assembly 40, is positioned near the stator 60. The magnetic collecting yoke 50 is a component for detecting changes in the magnetic flux acting on the stator 60 from the magnet 65, and is positioned near the flange portion 61 of the stator 60. Since the stator 60 consists of a pair of first stators 60a and second stators 60b, the magnetic collecting yoke 50 also consists of a pair of magnetic collecting yokes 51 and second magnetic collecting yokes 52. Specifically, the first magnetic collecting yoke 51 is positioned near the first flange portion 61a of the first stator 60a, and the second magnetic collecting yoke 52 is positioned near the second flange portion 61b of the second stator 60b.

[0052] The pair of magnetic collecting yokes 50 are located radially outward from the teeth portion 62 of the stator 60, between the 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. In other words, the first magnetic collecting yoke 51 is positioned near the side of the first flange portion 61a of the first stator 60a where the second flange portion 61b is located, and the second magnetic collecting yoke 52 is positioned near the side of the second flange portion 61b of the second stator 60b where the first flange portion 61a is located. These magnetic collecting yokes 50 overlap with the flange portions 61 of the stator 60 within a predetermined range in the circumferential direction.

[0053] Furthermore, the pair of magnetic collecting yokes 50 may be positioned such that they sandwich the two flange portions 61 of the pair of stators 60 from both sides in the axial direction. In other words, the first magnetic collecting yoke 51 may be positioned near the opposite side of the first flange portion 61a of the first stator 60a from the side where the second flange portion 61b is located, and the second magnetic collecting yoke 52 may be positioned near the opposite side of the second flange portion 61b of the second stator 60b from the side where the first flange portion 61a is located. The pair of magnetic collecting yokes 50 may be positioned between the first flange portion 61a and the second flange portion 61b as long as they overlap the flange portions 61 of the stator 60 in a predetermined range in the circumferential direction, and the pair of magnetic collecting yokes 50 may be positioned such that they sandwich the first flange portion 61a and the second flange portion 61b from both sides in the axial direction.

[0054] In this way, by positioning the magnetic collecting yoke 50 near the flange portion 61, the pair of magnetic collecting yokes 50 are able to 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 collecting yoke 50 is able to detect changes in the magnetic flux acting from the magnet 65 to the stator 60 when the stub shaft 86 and the first pinion gear 91 rotate relatively small amounts.

[0055] Furthermore, a Hall IC 55 is positioned between the two magnetic collecting yokes 50. The Hall IC 55 is positioned between the magnetic collecting yokes 50 at a location away from the portion of the magnetic collecting yoke 50 that is near the flange portion 61 of the stator 60. In other words, the Hall IC 55 is sandwiched between the first magnetic collecting yoke 51 and the second magnetic collecting yoke 52 of the magnetic collecting yoke 50. The Hall IC 55 has a Hall element (not shown) that detects changes in magnetic flux detected by the magnetic collecting yokes 50, and an output circuit (not shown) that converts the output voltage output from the Hall element in response to the change in magnetic flux into a digital electrical signal. As a result, the Hall IC 55 can detect changes in magnetic flux density acting on the two magnetic collecting yokes 50, convert the detected change in magnetic flux density into an electrical signal, and output it as an electrical signal. Note that a magnetic sensor that applies the magnetoresistance effect or the tunnel magnetoresistance effect can be used instead of the Hall IC 55. In short, it is sufficient to output the change in magnetic flux density occurring between the magnetic collecting yokes 50 as an electrical signal.

[0056] As shown in Figure 2, the magnet 65 is attached to the stub shaft 86 by a first sleeve 66. The first sleeve 66 is a cylindrical member, and the first sleeve 66 is attached to the stub shaft 86 by press-fitting the stub shaft 86 into the first sleeve 66. The magnet 65 is fixed to the outer surface of the first sleeve 66, for example, with adhesive, so that the magnet 65 can rotate integrally with the stub shaft 86.

[0057] As shown in Figure 2, the stator 60 is attached to the first pinion gear 91 by a second sleeve 63 and a carrier 64. The second sleeve 63 is a cylindrical member, and the second sleeve 63 is attached to the first pinion gear 91 by press-fitting the first pinion gear 91 into the second sleeve 63. The carrier 64 is a cylindrical member and is integrally formed with the second sleeve 63 by injection molding. Therefore, when the second sleeve 63 is attached to the first pinion gear 91, the carrier 64 is also attached to the first pinion gear 91 together with the second sleeve 63.

[0058] The carrier 64, which is attached to the first pinion gear 91 by the second sleeve 63, is supported by the second sleeve 63 and positioned toward the stub shaft 86 side from the first pinion gear 91, and is located radially outward of the stub shaft 86. Furthermore, the carrier 64 is positioned in the same axial position as the magnet 65 and is located radially outward of the magnet 65.

[0059] The stator 60 is attached to the carrier 64, which is arranged in this manner. More specifically, the first stator 60a and the second stator 60b are attached to the carrier 64 such that the teeth portion 62 is located on the inside of the carrier 64 in the radial direction, and the flange portion 61 protrudes from the inside to the outside of the carrier 64 in the radial direction. As a result, both the first stator 60a and the second stator 60b, which are a pair of stators 60, are positioned in the same axial position as the magnet 65, and are positioned radially outward from the magnet 65.

[0060] Furthermore, the first stator 60a and the second stator 60b are attached to a carrier 64 which is integrally formed with the second sleeve 63 that is attached to the first pinion gear 91, and are therefore able to rotate together with the first pinion gear 91. In other words, the stator 60, which is arranged to rotate together with the first pinion gear 91 in this way, has a flange portion 61 that protrudes outward in the radial direction of the first pinion gear 91 from the teeth portion 62 and is fixed to the first pinion gear 91.

[0061] As described above, the magnet 65 is fixed to the stub shaft 86 and the stator 60 is fixed to the first pinion gear 91, so that the magnet 65 and stator 60, which constitute the sensor body 58 of the torque sensor 10, are arranged inside the housing 20 together with the stub shaft 86 and the first pinion gear 91. More specifically, the torque sensor 10 is mainly arranged inside the sensor housing 21, and the magnet 65 and stator 60 of the torque sensor 10 are housed in the sensor housing 21 together with the stub shaft 86.

[0062] Since the magnet 65 and stator 60 of the torque sensor 10 are formed with a circular shape on their outer circumference when viewed in the axial direction, the shape of the inner circumferential surface 25 of the part of the sensor housing 21 that houses the magnet 65 and stator 60 is also formed with a circular shape when viewed in the axial direction, with a diameter larger than the diameter of the magnet 65 and stator 60.

[0063] In other words, the sensor housing 21 has a cylindrical sensor housing section 24, which houses the magnet 65 and stator 60. The diameter of the cylinder, i.e., the diameter of the inner circumferential surface 25 of the sensor housing section 24, is larger than the diameters of the magnet 65 and stator 60. In other words, the sensor housing section 24 houses the sensor body 58, and the diameter of the inner circumferential surface 25 of the sensor housing section 24 is larger than the diameter of the sensor body 58. The diameter of the inner circumferential surface 25 of the sensor housing section 24 of the sensor housing 21 is larger than, for example, the diameter of the flange section 61, which is the largest diameter part of the stator 60. Also, the diameter of the sensor housing section 24 of the sensor housing 21 is larger than the diameter of the bearing fitting section 22.

[0064] In the second housing 31, an insertion portion 32 is formed on the inner surface near the end that connects to the sensor housing 21 in the axial direction. The insertion portion 32 allows the end of the sensor housing 21 on the side where the second housing 31 is located to fit into it. A groove is provided on the outer circumferential surface of the portion of the sensor housing 21 that fits into the insertion portion 32, and an O-ring 35 is placed in this groove. As a result, a seal is ensured between the portion of the sensor housing 21 that fits into the insertion portion 32 and the second housing 31 by the O-ring 35.

[0065] The stub shaft 86 has a guide portion 87 on the side opposite to the side where the stator 60 is located in the axial direction of the stub shaft 86, relative to the portion where the bearing 70 is located. The guide portion 87 is provided on the stub shaft 86 from the portion where the bearing 70, which is located inside the sensor housing 21, is located, to the portion that extends from the inside of the sensor housing 21 to the outside of the sensor housing 21, toward the opposite side where the second housing 31 is located.

[0066] The guide portion 87 has a diameter slightly smaller than the diameter of the fitting portion 86a of the stub shaft 86 where the bearing 70 is positioned, and serves to guide the bearing 70 when assembling the sensor housing 21 and the bearing 70 to the stub shaft 86. In other words, the diameter of the guide portion 87 is only slightly smaller than the inner diameter of the bearing 70, and the difference in diameter with respect to the fitting portion 86a of the stub shaft 86 is small, making it possible to guide the bearing 70 to the fitting portion 86a. The diameter of the portion of the stub shaft 86 located on the side opposite to the side connected to the first pinion gear 91 from the position of the guide portion 87 is smaller than the diameter of the guide portion 87.

[0067] When assembling the sensor housing 21 to the stub shaft 86 formed in this way, the sensor housing 21 is assembled with the bearing 70 fitted into the bearing fitting portion 22, and the stub shaft 86 is passed through the bearing 70 fitted into the sensor housing 21 from the portion of the stub shaft 86 opposite to the side connected to the first pinion gear 91. The portion of the stub shaft 86 opposite to the side connected to the first pinion gear 91 from the guide portion 87 has a smaller diameter than the diameter of the guide portion 87. Therefore, when the portion of the stub shaft 86 opposite to the side connected to the first pinion gear 91 from the guide portion 87 passes through the bearing 70, the play between the bearing 70 and the stub shaft 86 becomes large. Thus, the stub shaft 86 has a small diameter portion 88 in the portion of the stub shaft 86 opposite to the side connected to the first pinion gear 91 from the guide portion 87, which has a smaller diameter than the diameter of the guide portion 87.

[0068] When the bearing 70 reaches the position of the guide portion 87 of the stub shaft 86, and the guide portion 87 passes inside the bearing 70, the diameter of the guide portion 87 is close to the inner diameter of the bearing 70, so the play between the stub shaft 86 and the bearing 70 is reduced. The sensor housing 21 into which the bearing 70 is fitted in the bearing fitting portion 22 is moved axially relative to the stub shaft 86, so that the bearing 70, which has less play with the stub shaft 86, slides against the guide portion 87 and is guided by the guide portion 87, moving relative to the stub shaft 86 in the axial direction toward the position of the fitting portion 86a. In this way, the guide portion 87 of the stub shaft 86 and the inner ring 72 of the bearing 70, whose outer ring 71 is fitted into the bearing fitting portion 22 of the sensor housing 21, are able to slide against each other when the stub shaft 86 is housed inside the sensor housing 21.

[0069] When the bearing 70 reaches the position of the fitting portion 86a of the stub shaft 86, the bearing 70 fits into the fitting portion 86a, and the bearing 70 and the sensor housing 21 are positioned in a predetermined positional relationship with respect to the stub shaft 86.

[0070] Figure 4 is a schematic diagram showing the relationship between the length of the guide portion 87 of the stub shaft 86 and the length of the sensor housing 21 in the axial direction. In the stub shaft 86 having the guide portion 87, the axial length L1 from the guide end 87a, which is the end of the guide portion 87, to the end 58a of the sensor body 58 on the side where the guide portion 87 is located, is longer than the axial length L2 from the end of the bearing 70 on the side where the sensor body 58 is located to the end 23 of the sensor housing 21, when the sensor housing 21 is assembled to the stub shaft 86 and the bearing 70 is fitted into the fitting portion 86a of the stub shaft 86.

[0071] In this case, the guide end 87a is the end of the guide portion 87 of the stub shaft 86 that is opposite to the side on which the sensor body 58 is located in the axial direction relative to the bearing 70 that is fitted with the fitting portion 86a.

[0072] Furthermore, in this case, the end of the bearing 70 on the side where the sensor body 58 is located is the side of the bearing 70 that fits into the fitting portion 86a of the stub shaft 86 in the axial direction, on the side where the sensor body 58 is located in the axial direction. Also, in this case, the end 23 of the sensor housing 21 is the end 23 of the sensor housing 21 on the side where the sensor body 58 is located relative to the bearing 70 that fits into the fitting portion 86a of the stub shaft 86, that is, it is the end of the sensor housing 21 on the side where the second housing 31 (see Figure 2) is located in the axial direction. Therefore, the length L2 is the axial distance between the bearing 70 that fits into the bearing fitting portion 22 of the sensor housing 21 and the end 23 of the sensor housing 21 on the side where the second housing 31 is located.

[0073] Furthermore, the sensor housing 21 has an inner portion that opens axially toward the second housing 31 at the end opposite to the side where the bearing 70 is located in the axial direction. Therefore, the end 23 of the sensor housing 21 that defines the length L2 is the opening end 27 of the sensor housing 21, which is the end that opens toward the second housing 31. In other words, the sensor housing 21, which has a bearing fitting portion 22 on one end in the axial direction, has an opening end 27 on the other end in the axial direction, which is the end that opens axially. The stator 60 housed inside the sensor housing 21 is positioned between the bearing fitting portion 22 and the opening end 27 of the sensor housing 21 in the axial direction.

[0074] The stub shaft 86 having the guide portion 87 and the sensor housing 21 have an axial length L1 from the guide end 87a to the sensor body 58, which is defined as described above. This length L1 is longer than the axial length L2 from the end of the bearing 70 on the sensor body 58 side to the opening end 27 of the sensor housing 21 when the sensor housing 21 is assembled to the stub shaft 86 and the bearing 70 is fitted into the fitting portion 86a of the stub shaft 86. In other words, the stub shaft 86 and the sensor housing 21 satisfy the relationship L1 > L2 between the lengths L1 and L2.

[0075] In the first embodiment, the end 58a of the sensor body 58 on the side where the guide portion 87 is located is the same as the end 58a of the stator 60 of the sensor body 58 on the side where the guide portion 87 is located. Therefore, the axial length L1 from the guide end 87a to the end 58a of the sensor body 58 on the side where the guide portion 87 is located is the same as the axial length L1 from the guide end 87a to the end 58a of the stator 60 on the side where the guide portion 87 is located. Also, the axial length L2 from the end of the bearing 70 on the side where the sensor body 58 is located to the end 23 of the sensor housing 21 is the same as the axial length L2 from the end of the bearing 70 on the side where the stator 60 is located to the end 23 of the sensor housing 21.

[0076] Therefore, the axial length L1 of the stub shaft 86 and the sensor housing 21, from the guide end 87a to the end 58a on the side of the stator 60 where the guide portion 87 is located, is longer than the axial length L2 of the bearing 70 from the end on the stator 60 side to the opening end 27 of the sensor housing 21, when the sensor housing 21 is assembled to the stub shaft 86 and the bearing 70 is fitted into the fitting portion 86a of the stub shaft 86.

[0077] Next, the operation of the steering device 80 will be explained. 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 84, and from the intermediate shaft 84 to the first pinion gear 91 via the stub shaft 86. As a result, the steering gear 90, which has the first pinion gear 91, converts the rotational motion transmitted from the first pinion gear 91 into linear motion of the rack bar 93, and operates the tie rod 98.

[0078] Furthermore, the steering device 80 according to the first embodiment has an electric motor 102 that generates auxiliary steering torque to assist the driver's steering. The electric motor 102 generates auxiliary steering torque based on the steering torque detected by a torque sensor 10 positioned between the stub shaft 86 and the first pinion gear 91.

[0079] The torque sensor 10 detects the steering torque applied to the stub shaft 86 based on the angle of relative rotation when the stub shaft 86 and the first pinion gear 91 rotate relative to each other. That is, since the stub shaft 86 and the first pinion gear 91 are connected via a torsion bar 95, when steering torque is applied to the stub shaft 86, the steering torque is transmitted between the stub shaft 86 and the first pinion gear 91 via the torsion bar 95. At that time, the torsion bar 95 twists slightly, causing the stub shaft 86 and the first pinion gear 91 to rotate relative to each other.

[0080] The torque sensor 10 has a magnet 65 attached to the stub shaft 86 and a stator 60 attached to the first pinion gear 91. When the stub shaft 86 and the first pinion gear 91 rotate relative to each other, the magnet 65 and stator 60 of the torque sensor 10 also rotate relative to each other. The angle of relative rotation between the magnet 65 and the stator 60 increases as the steering torque acting between the stub shaft 86 and the first pinion gear 91 increases.

[0081] When the magnet 65 and the stator 60 rotate relative to each other, the magnetic flux acting from the magnet 65 to the stator 60 changes. The magnetic collecting yoke 50, positioned near the stator 60, is capable of detecting changes in the magnetic flux acting from the magnet 65 to the stator 60. Therefore, when the magnet 65 and the stator 60 rotate relative to each other due to the relative rotation of the stub shaft 86 and the first pinion gear 91, the magnetic collecting yoke 50, positioned near the stator 60, can detect changes in the magnetic flux acting from the magnet 65 to the stator 60.

[0082] In this way, the magnetic flux acting from the magnet 65 on the stator 60, as detected by the pair of magnetic collecting yokes 50, changes according to the angle of relative rotation between the magnet 65 and the stator 60. The Hall IC 55 detects the magnetic flux that changes according to the angle of relative rotation between the magnet 65 and the stator 60, as detected by the magnetic collecting yokes 50, using a Hall element, and converts it into an electrical signal in its output circuit, which is then transmitted to the ECU 100. In other words, the torque sensor 10 detects the steering torque applied to the stub shaft 86 by detecting the change in magnetic flux acting from the magnet 65 on the stator 60 using the magnetic collecting yokes 50 and the Hall IC 55, and transmits the detected steering torque as an electrical signal to the ECU 100.

[0083] The ECU 100 operates the electric motor 102 based on the electrical signal transmitted from the torque sensor 10, generating auxiliary steering torque in the electric motor 102. In other words, the electrical signal transmitted from the Hall IC 55 of the torque sensor 10 to the ECU 100 changes according to the angle of relative rotation between the magnet 65 and the stator 60, and changes based on the steering torque T acting between the stub shaft 86 and the first pinion gear 91. Therefore, the ECU 100 uses the electrical signal transmitted from the Hall IC 55 of the torque sensor 10 as information that changes according to the steering torque T acting on the stub shaft 86 and the first pinion gear 91, and adjusts the power value E supplied to the electric motor 102 based on the electrical signal transmitted from the Hall IC 55, thereby generating auxiliary steering torque in the electric motor 102.

[0084] Specifically, the ECU 100 acquires a steering torque T signal from the torque sensor 10, a vehicle speed signal V from the vehicle speed sensor 101, and further acquires operation information M of the electric motor 102 from a rotation detection device provided on the electric motor 102. Based on this operation information M, the steering torque T, and the vehicle speed signal V, the ECU 100 generates auxiliary steering torque in the electric motor 102. The auxiliary steering torque generated by the electric motor 102 is transmitted to the second pinion gear 94. The steering gear 90, which has the second pinion gear 94, converts the rotational motion transmitted from the second pinion gear 94 into linear motion of the rack bar 93. As a result, the steering force applied by the driver to the steering wheel 81 is assisted by the auxiliary steering torque generated by the electric motor 102.

[0085] Next, the process of passing the stub shaft 86 inside the sensor housing 21 during the assembly process of the torque sensor 10 will be described. Figure 5 is a schematic diagram showing the state in which the stub shaft 86 is being passed inside the sensor housing 21 shown in Figure 4. In Figure 5, the dashed line indicates that the sensor housing 21 is tilted relative to the stub shaft 86. In the assembly process of the torque sensor 10, when the stator 60 of the sensor body 58 is housed inside the sensor housing 21, the stub shaft 86, which is connected to the first pinion gear 91 to which the stator 60 is attached via a torsion bar 95 (see Figure 2), is passed through the bearing 70 fitted to the bearing fitting portion 22 of the sensor housing 21. When passing the stub shaft 86 through the bearing 70, it is passed inside the bearing 70 from the side of the narrow diameter portion 88 located on the opposite side of the guide portion 87 from the side where the first pinion gear 91 is located.

[0086] The narrow-diameter portion 88 of the stub shaft 86 has a diameter smaller than the inner diameter of the bearing 70 and smaller than the diameter of the guide portion 87. Therefore, when the narrow-diameter portion 88 of the stub shaft 86 is passing through the bearing 70, the play between the bearing 70 and the stub shaft 86 becomes large. As a result, the sensor housing 21 into which the bearing 70 is fitted can tilt significantly relative to the stub shaft 86 due to the play between the bearing 70 and the stub shaft 86, as shown by the dashed line in Figure 5.

[0087] However, the axial length L1 of the stub shaft 86 and the sensor housing 21, from the guide end 87a to the end 58a on the side of the stator 60 where the guide portion 87 is located, is longer than the axial length L2 of the bearing 70 from the end on the stator 60 side to the opening end 27 of the sensor housing 21 when the sensor housing 21 is assembled to the stub shaft 86 and the bearing 70 is fitted into the fitting portion 86a of the stub shaft 86.

[0088] Therefore, when the bearing 70 fitted into the bearing fitting portion 22 of the sensor housing 21 is positioned at the location of the narrow diameter portion 88 of the stub shaft 86, the open end portion 27 of the sensor housing 21 will be located closer to the guide portion 87 than the end portion 58a of the stator 60 where the guide portion 87 is located. Consequently, even if the sensor housing 21 tilts significantly relative to the stub shaft 86 due to play between the bearing 70 and the stub shaft 86, as shown by the dashed line in Figure 5, contact between the sensor housing 21 and the stator 60 is suppressed.

[0089] Figure 6 is an explanatory diagram regarding the size of the inner circumferential surface 25 of the sensor housing 21. Figure 7 is an explanatory diagram regarding the inclination of the sensor housing 21 when the bearing 70 fitted into the sensor housing 21 is positioned on the guide portion 87 of the stub shaft 86. In Figure 7, the dashed line indicates the state in which the sensor housing 21 is inclined relative to the stub shaft 86, and HL in Figure 7 indicates the central axis of the sensor housing 21 inclined relative to the stub shaft 86. In the first embodiment, the distance C between the flange portion 61 of the stator 60 attached to the first pinion gear 91 and the inner circumferential surface 25 of the sensor housing 21 is 2 mm or less. Also in the first embodiment, the diameter of the inner circumferential surface 25 of the sensor housing 21 is sized such that it does not come into contact with the stator 60 even when the sensor housing 21 is inclined relative to the stub shaft 86 when the bearing 70 fitted into the bearing fitting portion 22 of the sensor housing 21 is positioned on the guide portion 87 of the stub shaft 86.

[0090] The sensor housing 21 satisfies 2 × L2 tanθ < D2 - D1 when the diameter of the inner circumferential surface 25 of the sensor housing portion 24 that houses the stator 60 in the sensor housing 21 is D2, the maximum diameter of the sensor body 58 is D1, the axial length from the end of the bearing 70 on the side where the sensor body 58 is located to the opening end 27 of the sensor housing 21 is L2, and the angle of inclination of the sensor housing 21 with respect to the axial direction when the bearing 70 that fits into the bearing fitting portion 22 of the sensor housing 21 is located on the guide portion 87 of the stub shaft 86 is θ. In the first embodiment, the maximum diameter D1 of the sensor body 58 is the diameter D1 of the flange portion 61 of the stator 60 that constitutes the sensor body 58.

[0091] In this case, the inclination angle θ is the maximum inclination angle of the central axis HL of the sensor housing 21 with respect to the central axis SL of the stub shaft 86, when the guide portion 87 of the stub shaft 86 passes through the bearing 70 that fits into the bearing fitting portion 22 of the sensor housing 21, as shown in Figure 7. In this case, the central axis HL of the sensor housing 21 is the central axis of the cylindrical sensor storage portion 24 in the sensor housing 21.

[0092] In other words, the guide portion 87 of the stub shaft 86 has a larger diameter than the narrow portion 88 of the stub shaft 86, and the diameter of the guide portion 87 is close to the inner diameter of the bearing 70. Therefore, when the guide portion 87 of the stub shaft 86 is located inside the bearing 70, the play between the bearing 70 and the stub shaft 86 is smaller compared to the part where the narrow portion 88 of the stub shaft 86 is located inside the bearing 70. Consequently, when the guide portion 87 of the stub shaft 86 is located inside the bearing 70, the maximum angle θ of the inclination of the central axis HL of the sensor housing 21 with respect to the central axis SL of the stub shaft 86 is smaller compared to the part where the narrow portion 88 of the stub shaft 86 is located inside the bearing 70.

[0093] Since the D1, D2, L2, and θ defined in this way satisfy 2 × L2 tan θ < D2 - D1, the sensor housing 21 can prevent contact between the sensor housing 21 and the stator 60 of the sensor body 58 during the process of attaching the sensor housing 21 to the stub shaft 86 connected to the first pinion gear 91 to which the stator 60 is attached.

[0094] In other words, when the sensor housing 21 is tilted relative to the stub shaft 86 due to play between the bearing 70 and the guide portion 87, the minimum gap Dx between the stator 60 and the sensor housing 21 when the sensor housing 21 is tilted relative to the stub shaft 86 due to play between the bearing 70 and the guide portion 87 satisfies the following equation (1) with respect to D1 and D2 above, then the sensor housing 21 will not come into contact with the stator 60 even when it is tilted. Dx < (D2 - D1) / 2 ... (1)

[0095] The minimum gap Dx when the stub shaft 86 is tilted can be expressed by the following equation (2) using L2 and θ as described above, and equation (2) can be converted to the following equation (3): Dx / L2 = tanθ ... (2) Dx = L2 × tanθ ... (3)

[0096] Substituting the right-hand side of equation (3) into equation (1) above yields equation (4), which can then be transformed into equation (5). L2tanθ < (D2 - D1) / 2 ... (4) 2 × L2tanθ < D2 - D1 ... (5)

[0097] Therefore, by satisfying the conditions of equation (5) above, the sensor housing 21 can suppress contact between the sensor housing 21 and the stator 60 of the sensor body 58 when the sensor housing 21 is tilted relative to the stub shaft 86 while the bearing 70 fitted into the bearing fitting portion 22 of the sensor housing 21 is positioned at the guide portion 87 of the stub shaft 86.

[0098] Figure 8 is a detailed view of the main parts of the sensor housing 21 shown in Figure 2. The sensor housing 21 has a magnetic yoke housing section 26 that houses the magnetic yoke assembly 40 (see Figure 2). The magnetic yoke housing section 26 is formed in the shape of a hole that communicates with the sensor housing section 24, which houses the stator 60 (see Figure 2) and magnet 65 (see Figure 2) that constitute the sensor body 58, from the outside of the sensor housing 21. The magnetic yoke assembly 40 is positioned inside the magnetic yoke housing section 26 and fixed to the sensor housing 21. As a result, the magnetic yoke 50 (see Figure 3) provided on the magnetic yoke assembly 40 is fixed to the sensor housing 21 when the magnetic yoke assembly 40 is fixed to the sensor housing 21, and is positioned near the flange portion 61 (see Figure 3) of the stator 60.

[0099] Furthermore, in the sensor housing 21, the size of the inner circumferential surface 25 of the sensor housing 24 in the direction perpendicular to the axial direction increases as you move axially from the side where the bearing fitting portion 22 is located to the side where the opening end portion 27 is located. In other words, the inner circumferential surface 25 of the cylindrical sensor housing 24 is formed in a tapered shape, where the inner diameter increases as you move axially from the side where the bearing fitting portion 22 is located to the side where the opening end portion 27 is located.

[0100] The sensor housing 21 is formed such that the inner diameter of the inner circumferential surface 25 of the sensor housing portion 24 increases from the position on the bearing fitting portion 22 side to the position on the opening end portion 27 side. As shown in Figure 7, when the sensor housing 21 is tilted with the guide portion 87 of the stub shaft 86 passing inside the bearing 70, the inner circumferential surface 25 is less likely to come into contact with the stator 60.

[0101] As described above, in the torque sensor 10 according to the first embodiment, the stub shaft 86 connected to the first pinion gear 91 via the torsion bar 95 has a guide portion 87 with a diameter slightly smaller than the fitting portion 86a, and the length L1 from the guide end 87a of the guide portion 87 to the end 58a of the sensor body 58 attached to the first pinion gear 91 on the side where the guide portion 87 is located is longer than the length L2 from the bearing 70 to the end 27 of the sensor housing 21 on the side where the sensor body 58 is located relative to the bearing 70. Therefore, when passing the stub shaft 86 through the bearing 70 fitted to the sensor housing 21 in order to assemble the sensor housing 21 to the stub shaft 86, the sensor housing 21 can be prevented from reaching the position of the sensor body 58 attached to the first pinion gear 91 when the small diameter portion 88 of the stub shaft 86 is passing through the bearing 70.

[0102] As a result, even if the sensor housing 21 tilts significantly relative to the stub shaft 86 due to play between the bearing 70 and the stub shaft 86, when the narrow-diameter portion 88 of the stub shaft 86 passes inside the bearing 70 fitted into the sensor housing 21, it is possible to suppress the sensor housing 21 from contacting the sensor body 58. Therefore, even when the sensor housing 21 is miniaturized, it is possible to suppress the sensor housing 21 from contacting the sensor body 58 when assembling the sensor housing 21 to the stub shaft 86. As a result, it is possible to miniaturize the sensor housing 21 while suppressing interference between the sensor body 58 and the sensor housing 21, which are components of the torque sensor 10.

[0103] Furthermore, the relationship between the maximum diameter D1 of the sensor body 58, the diameter D2 of the inner circumferential surface 25 of the sensor housing 21, the length L2 from the bearing 70 to the end 23 on the side where the sensor body 58 is positioned relative to the bearing 70 that fits into the sensor housing 21, and the angle θ of the tilt of the sensor housing 21 when the bearing 70 that fits into the sensor housing 21 is positioned on the guide portion 87 of the stub shaft 86 satisfies 2 × L2 tan θ < D2 - D1. As a result, when the sensor housing 21 is tilted while the bearing 70 that fits into the sensor housing 21 is positioned on the guide portion 87 of the stub shaft 86, the sensor housing 21 can be prevented from contacting the sensor body 58.

[0104] Furthermore, the outer ring 71 of the bearing 70 fits into the sensor housing 21, and the guide portion 87 of the stub shaft 86 and the inner ring 72 of the bearing 70 can slide against each other when the stub shaft 86 is housed inside the sensor housing 21. This prevents the sensor housing 21 from tilting too much and contacting the stator 60, while ensuring ease of assembly of the sensor housing 21 to the stub shaft 86. As a result, interference between the stator 60 and the sensor housing 21 is suppressed, the ease of assembly of the torque sensor 10 is improved, and manufacturing costs can be reduced.

[0105] Furthermore, the sensor housing 21 has an inner circumferential surface 25 in the portion that houses the sensor body 58, and the size of this surface in the direction perpendicular to the axial direction increases from the side where the bearing fitting portion 22 is located to the side where the opening end portion 27 is located in the axial direction. Therefore, when the sensor housing 21 is tilted with the bearing 70 fitted into the sensor housing 21 positioned on the guide portion 87 of the stub shaft 86, the sensor housing 21 is less likely to come into contact with the sensor body 58. As a result, interference between the sensor body 58 and the sensor housing 21 can be suppressed while the sensor housing 21 can be made smaller.

[0106] [Second Embodiment] Next, the torque sensor 10 according to the second embodiment will be described. Components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. The following description will focus on the differences from the first embodiment.

[0107] Figure 9 is a side view of the torque sensor 10 according to the second embodiment. Figure 10 is a perspective view of the magnetic collecting yoke assembly 40 and the sensor body 58 in the torque sensor 10 according to the second embodiment. Figure 11 is a view taken along the line A-A in Figure 9. The torque sensor 10 according to the second embodiment has a steering angle sensor 120 that detects the steering angle of the steering shaft 82 and stub shaft 86 that rotate together with the steering wheel 81. The steering angle sensor 120 is electrically connected to the ECU 100 and can output the steering angle of the steering wheel 81 to the ECU 100 via CAN communication.

[0108] The steering angle sensor 120 includes a main gear 121 and a driven gear 125. The main gear 121 is an annular gear that rotates in conjunction with the rotation of the steering wheel 81 and the first pinion gear 91, with gears mounted on the outer circumference of the annule. In the second embodiment, the main gear 121 is located on the sensor body 58 of the torque sensor 10. That is, the main gear 121 is mounted on the stator 60 of the sensor body 58 with the central axis of the annule coinciding with the central axis of the first pinion gear 91.

[0109] More specifically, the main gear 121 is mounted on the outer circumferential surface of the teeth portion 62 of the stator 60 and positioned between the first flange portion 61a of the first stator 60a and the second flange portion 61b of the second stator 60b. The outer diameter of the main gear 121 is smaller than the outer diameters of the first flange portion 61a and the second flange portion 61b. For this reason, the first flange portion 61a and the second flange portion 61b of the stator 60 protrude radially outward from the main gear 121 mounted on the outer circumferential surface of the teeth portion 62. The main gear 121 of the steering angle sensor 120, which is mounted on the stator 60 of the torque sensor 10, together with the stator 60, constitutes the sensor body 58.

[0110] The driven gear 125 is a gear that meshes with the gear on the outer circumference of the main gear 121, and the gear that meshes with the gear of the main gear 121 is located on the outer circumference of the driven gear 125. The driven gear 125 is positioned so that its axis of rotation is parallel to the axis of rotation of the first pinion gear 91 and the main gear 121. Because the driven gear 125 meshes with the main gear 121, it is able to rotate by transmitting the rotation of the main gear 121, which rotates together with the first pinion gear 91. The steering angle sensor 120 has two driven gears 125, and each of the two driven gears 125 meshes with the main gear 121, and is able to rotate by transmitting the rotation of the main gear 121.

[0111] The steering angle sensor 120 also includes a magnet 126 and a sensor (not shown). The magnet is positioned on the driven gear 125 and rotates together with the driven gear 125 when the driven gear 125 rotates. The magnet 126 is positioned on each of the two driven gears 125 of the steering angle sensor 120, and the magnet 126 positioned on each driven gear 125 is positioned inside the gear of the driven gear 125 in the radial direction of the driven gear 125. The magnet 126 has alternating south and north poles magnetized on its outer surface. Therefore, when the magnet 126 rotates, the magnet 126, which rotates together with the driven gear 125, has its south and north poles rotate around the rotation axis of the driven gear 125, that is, the magnetic field of the magnet 126 rotates in conjunction with the rotation of the driven gear 125.

[0112] The sensor detects the rotation of the driven gear 125. The sensor is, for example, a Hall-type magnetic sensor having a Hall element, and includes a Hall element (not shown) that detects changes in the magnetic flux of a magnet 126 placed on the driven gear 125, and an output circuit (not shown) that converts the output voltage output from the Hall element in response to the change in magnetic flux into a digital electrical signal. In addition to the Hall-type magnetic sensor, a magnetic sensor that utilizes the magnetoresistance effect or the tunnel magnetoresistance effect may also be used.

[0113] The sensor detects the rotation of the driven gear 125 by detecting the magnetic flux of the magnet 126 placed on the driven gear 125 and detecting the movement of the magnetic field. In other words, the sensor 18 detects the rotation of the driven gear 125 by detecting the change in the magnetic field from the magnet 126, which rotates integrally with the driven gear 125, in the circumferential direction around the rotation axis of the driven gear 125. The steering angle sensor 120 has two sensors corresponding to the two driven gears 125 that the steering angle sensor 120 has, and the two sensors are capable of detecting the rotation of the corresponding driven gear 125. The sensor can detect the movement of the main gear 121 in the circumferential direction around the rotation axis of the first pinion gear 91 by detecting the rotation of the driven gear 125, and is capable of detecting the steering angle of the first pinion gear 91, that is, the steering angle of the steering wheel 81.

[0114] The two driven gears 125 and the two sensors are each provided on a magnetic collecting yoke assembly 40 of the torque sensor 10. The driven gears 125 are rotatably supported within the magnetic collecting yoke assembly 40, and the sensors are positioned within the magnetic collecting yoke assembly 40 so as to be able to detect the rotation of the driven gears 125 by detecting the magnetic field of a magnet 126 placed on the driven gears 125. For this reason, the sensors are positioned near the driven gears 125 within the magnetic collecting yoke assembly 40, specifically, near the driven gears 125 in the axial direction of the rotation axis of the driven gears 125. The sensors are positioned near the driven gears 125 within the magnetic collecting yoke assembly 40 by, for example, mounting them on a printed circuit board (not shown) located within the magnetic collecting yoke assembly 40.

[0115] In this way, the steering angle sensor 120, which is formed integrally with the torque sensor 10, detects the rotation state of the first pinion gear 91 as the steering angle when the steering shaft 82 rotates due to the operation of the steering wheel 81, and the stub shaft 86 and the first pinion gear 91 rotate together with the steering shaft 82. In other words, when the first pinion gear 91 rotates, the steering angle sensor 120 detects when the main gear 121, which is attached to the first pinion gear 91 via the stator 60 of the torque sensor 10, rotates together with the first pinion gear 91, and the rotation of the main gear 121 is transmitted to the driven gear 125, causing the driven gear 125 to rotate as well. When the driven gear 125 rotates, the magnet 126 placed on the driven gear 125 also rotates together with it, and the change in the magnetic flux of the rotating magnet 126 is detected by a sensor placed near the driven gear 125.

[0116] The steering angle sensor 120 detects the rotation angle of the driven gear 125 based on the change in magnetic flux of the magnet 126 detected by the sensor, and converts the rotation angle of the driven gear 125 into the rotation angle of the main gear 121 based on the gear ratio between the main gear 121 and the driven gear 125. As a result, the steering angle sensor 120 determines the rotation angle of the first pinion gear 91 on which the main gear 121 is located, and detects the rotation angle of the first pinion gear 91 as the steering angle of the steering wheel 81 or the steering shaft 82.

[0117] Here, of the two driven gears 125 of the steering angle sensor 120, one driven gear 125 detects the rotational position of the first pinion gear 91 in the circumferential direction, and the other driven gear 125 detects the rotational speed of the first pinion gear 91. Therefore, the steering angle sensor 120 can detect the current rotational speed and rotational position of the first pinion gear 91 in the circumferential direction using the two driven gears 125 that mesh with the main gear 121. Consequently, the steering angle sensor 120 can detect the current rotational position of the first pinion gear 91 within its rotational range as the steering angle of the steering wheel 81 or the steering shaft 82.

[0118] In this way, the steering angle detected by the steering angle sensor 120 is converted into an electrical signal and transmitted to the ECU 100 (see Figure 1) as an output signal from the steering angle sensor 120. In other words, the steering angle sensor 120 detects the steering angle of the steering shaft 82 by detecting the change in the magnetic flux of the magnet 126 placed on the driven gear 125, which changes with the rotation of the driven gear 125, using the sensor 18, and transmits the detected steering angle as an electrical signal to the ECU 100.

[0119] The ECU 100 operates the electric motor 102 (see Figure 1) based on the steering angle transmitted from the steering angle sensor 120 and the steering torque transmitted from the torque sensor 10, generating auxiliary steering torque in the electric motor 102. In other words, the ECU 100 adjusts the power value supplied to the electric motor 102 based on the steering angle transmitted from the steering angle sensor 120 and the steering torque transmitted from the torque sensor 10, generating auxiliary steering torque in the electric motor 102 corresponding to the transmitted steering angle and steering torque.

[0120] Specifically, the ECU 100 acquires a steering angle signal from the steering angle sensor 120, a steering torque signal from the torque sensor 10, a vehicle speed signal from the vehicle speed sensor 101 (see Figure 1), and further acquires operation information of the electric motor 102 from a rotation detection device provided on the electric motor 102. Based on this operation information, the steering angle, steering torque, and vehicle speed signals, the ECU 100 generates auxiliary steering torque in the electric motor 102. The auxiliary steering torque generated by the electric motor 102 is transmitted to the rack bar 93 (see Figure 1) via the second pinion gear 94 (see Figure 1). As a result, the steering force applied by the driver to the steering wheel 81 is assisted by the auxiliary steering torque generated by the electric motor 102.

[0121] Thus, even when the steering angle sensor 120 is formed integrally with the torque sensor 10, the axial length L1 from the guide end 87a, which is the end of the guide portion 87 of the stub shaft 86 (see Figure 4), to the end 58a of the sensor body 58 on the side where the guide portion 87 is located, is longer than the axial length L2 from the end of the bearing 70 on the side where the sensor body 58 is located to the end 23 of the sensor housing 21, when the sensor housing 21 (see Figure 4) is assembled to the stub shaft 86 and the bearing 70 (see Figure 4) is fitted into the fitting portion 86a of the stub shaft 86.

[0122] As a result, when assembling the sensor housing 21 to the stub shaft 86, if the small diameter portion 88 of the stub shaft 86 is passing through the bearing 70, the sensor housing 21 can be prevented from reaching the position of the sensor body 58 which is attached to the first pinion gear 91. Even if the sensor housing 21 is tilted significantly relative to the stub shaft 86, contact between the sensor housing 21 and the sensor body 58 can be suppressed. Therefore, even when the sensor housing 21 is miniaturized, contact between the sensor housing 21 and the sensor body 58 can be suppressed when assembling the sensor housing 21 to the stub shaft 86, and the sensor housing 21 can be miniaturized while suppressing interference between the sensor body 58 and the sensor housing 21.

[0123] Furthermore, the outer diameter of the main gear 121 of the steering angle sensor 120 is smaller than the outer diameter of the flange portion 61 of the stator 60 of the torque sensor 10. For this reason, in the second embodiment as well, the maximum diameter D1 of the sensor body 58 is equal to the diameter D1 of the flange portion 61 of the stator 60.

[0124] As a result, in the second embodiment as well, the relationship between the maximum diameter D1 of the sensor body 58, which is the diameter D1 of the flange portion 61 of the stator 60, the diameter D2 of the inner circumferential surface 25 of the sensor housing 21, the axial length L2 from the end of the bearing 70 on the side where the sensor body 58 is located to the opening end 27 of the sensor housing 21, and the angle θ of the tilt of the sensor housing 21 when the bearing 70 fitted into the sensor housing 21 is positioned on the guide portion 87 of the stub shaft 86, satisfies 2 × L2 tan θ < D2 - D1. Therefore, when the sensor housing 21 is tilted when the bearing 70 fitted into the sensor housing 21 is positioned on the guide portion 87 of the stub shaft 86, it is possible to suppress the sensor housing 21 from coming into contact with the sensor body 58, thereby suppressing interference between the sensor body 58 and the sensor housing 21 while miniaturizing the sensor housing 21.

[0125] [Third Embodiment] Next, the torque sensor 10 according to the third embodiment will be described. Components identical to those in the first embodiment are given the same reference numerals and their descriptions are omitted. The following description will focus on the differences from the first embodiment.

[0126] Figure 12 is a cross-sectional view of the main part of the torque sensor 10 according to the third embodiment. Figure 13 is a cross-sectional view of the main part of the torque sensor 10 at a different position than in Figure 12. Figure 14 is a perspective view of the torque sensor 10 according to the third embodiment. The torque sensor 10 according to the third embodiment has an inner housing 150 that is arranged on the radially outer side of the stator 60. The inner housing 150, together with the stator 60 and the magnet 65, constitutes the sensor body 58 of the torque sensor 10. The inner housing 150 is formed in an annular shape and is arranged inside the housing 20. More specifically, the inner housing 150 is attached to the second housing 31 inside the housing 20 by mounting bolts 155.

[0127] The inner housing 150, which is attached to the second housing 31, is positioned so that its axial position is the same as the axial position of the stator 60 attached to the first pinion gear 91. The stator 60 attached to the first pinion gear 91 is positioned radially inside the inner housing 150 when the annularly formed inner housing 150 is attached to the second housing 31. In other words, the maximum diameter of the inner housing 150 is larger than the outer diameter of the flange portion 61 of the stator 60.

[0128] On the other hand, the maximum diameter of the inner housing 150 is smaller than the inner diameter of the sensor housing 21. More specifically, when the maximum diameter of the inner housing 150 is defined as twice the distance from the central axis of the first pinion gear 91 at the position where the distance from the central axis is greatest on the outer circumferential surface of the inner housing 150, the maximum diameter of the inner housing 150 is smaller than the inner diameter of the sensor housing 21. For this reason, the inner housing 150, which is attached to the second housing 31, is positioned inside the sensor housing 21 when the sensor housing 21 is attached to the second housing 31.

[0129] Furthermore, the inner housing 150 has a longer axial length than the stator 60 in the axial direction. Therefore, the end of the inner housing 150 on the side where the guide portion 87 (see Figure 4) of the stub shaft 86 is located is located closer to the guide portion 87 than the end of the stator 60 on the side where the guide portion 87 of the stub shaft 86 is located.

[0130] As a result, in the third embodiment, the end 58a of the sensor body 58 on the side where the guide portion 87 is located becomes the end 58a of the inner housing 150 on the side where the guide portion 87 is located in the axial direction. In this way, even in the third embodiment, where the end 58a of the inner housing 150 becomes the end 58a of the sensor body 58, the axial length L1 from the guide end 87a to the end 58a of the sensor body 58 is longer than the axial length L2 from the end of the bearing 70 on the side where the sensor body 58 is located to the end 23 of the sensor housing 21, when the sensor housing 21 (see Figure 4) is assembled to the stub shaft 86 and the bearing 70 (see Figure 4) is fitted into the fitting portion 86a of the stub shaft 86.

[0131] As a result, when assembling the sensor housing 21 onto the stub shaft 86, if the small diameter portion 88 of the stub shaft 86 is passing through the bearing 70, the sensor housing 21 will not reach the position of the sensor body 58 including the inner housing 150. Even if the sensor housing 21 is tilted significantly relative to the stub shaft 86, it is possible to suppress the sensor housing 21 from coming into contact with the sensor body 58 including the inner housing 150. Therefore, even if the sensor housing 21 is miniaturized, it is possible to suppress the sensor housing 21 from coming into contact with the sensor body 58 when assembling the sensor housing 21 onto the stub shaft 86, thereby miniaturizing the sensor housing 21 while suppressing interference between the sensor body 58 and the sensor housing 21.

[0132] Furthermore, in the third embodiment, the maximum diameter of the inner housing 150 is larger than the outer diameter of the stator 60, so the maximum diameter D1 of the sensor body 58 in the third embodiment is the maximum diameter of the inner housing 150. Also, the maximum diameter of the inner housing 150 is smaller than the inner diameter of the sensor housing 21. For this reason, in the third embodiment as well, the relationship between the maximum diameter D1 of the sensor body 58, which is the maximum diameter of the inner housing 150, the diameter D2 of the inner circumferential surface 25 of the sensor housing 21, the axial length L2 from the end of the bearing 70 on the side where the sensor body 58 is located to the opening end 27 of the sensor housing 21, and the inclination angle θ of the sensor housing 21 when the bearing 70 fitted into the sensor housing 21 is located on the guide portion 87 of the stub shaft 86 satisfies 2 × L2 tan θ < D2 - D1.

[0133] This prevents the sensor housing 21 from contacting the sensor body 58 when the sensor housing 21 is tilted while the bearing 70 that fits into the sensor housing 21 is positioned on the guide portion 87 of the stub shaft 86. This suppresses interference between the sensor body 58 and the sensor housing 21 while also enabling miniaturization of the sensor housing 21.

[0134] [Modification] In the first to third embodiments described above, the magnet 65 is attached to the stub shaft 86, which is the input shaft, and the stator 60 is attached to the first pinion gear 91, which is the output shaft. However, the shafts to which the magnet 65 and stator 60 are attached may be reversed. In other words, the magnet 65 may be attached to the output shaft, and the stator 60 may be attached to the input shaft.

[0135] Furthermore, in the first embodiment described above, the inner circumferential surface 25 of the sensor housing 24 of the sensor housing 21 is formed in a tapered shape in which the inner diameter increases as you move in the axial direction from the side where the bearing fitting portion 22 is located to the side where the opening end portion 27 is located. However, the inner circumferential surface 25 of the sensor housing 24 may be formed in a shape other than tapered. For example, the inner circumferential surface 25 of the sensor housing 24 of the sensor housing 21 may be formed in which the inner diameter increases in stages as you move in the axial direction from the side where the bearing fitting portion 22 is located to the side where the opening end portion 27 is located. By forming the inner circumferential surface 25 of the sensor housing 24 to be larger closer to the opening end portion 27 than closer to the bearing fitting portion 22, it is possible to make it difficult for the inner circumferential surface 25 of the sensor housing 21 to come into contact with the stator 60 when the sensor housing 21 is tilted with the guide portion 87 of the stub shaft 86 passing inside the bearing 70. This makes it possible to reduce the size of the sensor housing 21 while suppressing interference between the stator 60 and the sensor housing 21.

[0136] Furthermore, in the first to third embodiments described above, the steering device 80 is a dual-pinion type in which assist force is applied to the second pinion gear 94, but the steering device 80 is not limited to this. The steering device 80 may be, for example, an electric power steering device of the column assist type in which assist force is applied to the steering shaft 82, or a single-pinion assist type in which assist force is applied to the first pinion gear 91. Alternatively, it may be a rack assist type electric power steering device that applies assist force to the rack bar 93 without going through a pinion, such as a ball screw type in which assist force is applied to the rack bar 93 by a ball screw.

[0137] While preferred embodiments of this disclosure have been described above, this disclosure is not limited to those described in the embodiments described above. The configurations described as embodiments and modifications may be combined as appropriate.

[0138] 10 Torque sensor 20 Housing 21 Sensor housing 22 Bearing fitting part 23 End part 24 Sensor storage part 25 Inner circumferential surface 26 Magnetic collecting yoke housing part 27 Opening side end part 31 Second housing 40 Magnetic collecting yoke assembly 50 Magnetic collecting yoke 55 Hall IC 58 Sensor body 58a End part 60 Stator 61 Flange part 62 Teeth part 63 Second sleeve 64 Carrier 65 Magnet 66 First sleeve 70, 74 Bearings 71, 75 Outer ring 72, 76 Inner ring 78 Seal member 80 Steering device 81 Steering wheel 82 Steering shaft 83, 85 Universal joint 84 Intermediate shaft 86 Stub shaft 86a Fitting part 87 Guide part 87a Guide end 88 Small diameter part 90 Steering gear 91 First pinion gear 93 Rack bar 94 Second pinion gear 95 Torsion bar 98 Tie rod 100 ECU 101 Vehicle speed sensor 102 Electric motor 103 Ignition switch 104 Power supply 120 Steering angle sensor 121 Main gear 125 Driven gear 126 Magnet 150 Inner housing 155 Mounting bolts

Claims

1. A torque sensor comprising: an input shaft; an output shaft to which torque is transmitted via a torsion bar; a sensor body fixed to the output shaft or the input shaft; a sensor housing housing the input shaft and the sensor body; and a bearing that rotatably supports the input shaft relative to the sensor housing, wherein the input shaft has a guide portion on the side of the input shaft opposite to the side of the input shaft where the sensor body is located, in the axial direction of the input shaft with respect to the portion where the bearing is located, the guide portion having a diameter slightly smaller than the diameter of the portion of the input shaft where the bearing is located, and the axial length from the end of the guide portion on the side of the sensor body where the guide portion is located to the end of the sensor body where the guide portion is located to the end of the bearing where the sensor body is located to the end of the sensor housing where the sensor body is located relative to the bearing is longer than the axial length from the end of the bearing where the sensor body is located to the end of the sensor housing where the sensor body is located relative to the bearing.

2. The torque sensor according to claim 1, wherein the maximum diameter of the sensor body is D1, the inner circumferential surface of the sensor housing is formed circularly and the diameter of the inner circumferential surface of the sensor housing is D2, the axial length from the end of the bearing on the side where the sensor body is located to the end of the sensor housing on the side where the sensor body is located relative to the bearing is L2, and the angle of inclination of the sensor housing with respect to the axial direction when the bearing fitted inside the sensor housing is located on the guide portion of the input shaft is θ, such that 2 × L2 tanθ < D2 - D1.

3. The torque sensor according to claim 1 or 2, wherein the bearing has an outer ring and an inner ring, the outer ring is fitted into the sensor housing, and the guide portion of the input shaft and the inner ring are capable of sliding against each other when the input shaft is housed inside the sensor housing.

4. The torque sensor according to any one of claims 1 to 3, wherein the sensor housing has a bearing fitting portion on one end in the axial direction into which the bearing is fitted, and has an opening end on the other end in the axial direction which is an end that opens in the axial direction, the sensor body is disposed between the bearing fitting portion and the opening end of the sensor housing in the axial direction, and the magnitude of the inner circumferential surface of the portion housing the sensor body in the direction perpendicular to the axial direction increases from the side where the bearing fitting portion is located to the side where the opening end is located in the axial direction.

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