Electric power steering device

Abstract

An electric power steering device 50 is provided with: a shaft member 56 that transmits rotational torque; a detection member 20 that is disposed on the shaft member 56; sensors 16, 17 for that detect movement of the detection member 20 in a circumferential direction around the shaft member 56; a sensor housing 60 that has a bottom part 61 through which the shaft member 56 passes and a wall part 65 that is disposed around the bottom part 61; a sensor cover 70 that is attached to the sensor housing 60 from a side where the wall part 65 in the sensor housing 60 is located and that forms a housing part 80 together with the sensor housing 60; and a harness 82 that is electrically connected to the sensors 16, 17. The detection member 20 and the sensors 16, 17 are disposed inside the housing part 80. The bottom part 61 of the sensor housing 60 has a through-hole 62 through which the harness 82 passes. The harness 82 is disposed so as to extend across the inside and the outside of the housing part 80 through the through-hole 62.

Description

Electric power steering device

[0001] The present disclosure relates to an electric power steering device.

[0002] An electric power steering device that assists a driver's steering assists the driver by detecting the steering torque applied by the driver using a torque sensor and transmitting the output of a motor to an output shaft in accordance with the detected steering torque. For example, an electric power steering device described in Patent Document 1 includes a torque sensor that detects the steering torque based on the difference in rotational angle between an input shaft and an output shaft, and applies steering assist torque to a rack shaft by controlling the drive of an electric motor based on the detection result of the torque sensor. Also, in Patent Document 1, a cable connected to the torque sensor is attached to a mounting portion formed to protrude radially outward from the outer circumferential surface of a first housing that houses the torque sensor, and the cable is drawn into the first housing through a lead-in port provided on the end surface of the mounting portion by attaching a cable holder to the mounting portion.

[0003] JP 2018-171950 A

[0004] However, when a cable connected to the torque sensor, i.e., a harness, is inserted into the sensor housing that accommodates the torque sensor from the radial outside of the sensor housing, the sensor housing, including the harness, tends to become larger in size in the radial direction. If the sensor housing becomes larger, the entire area around the sensor housing in the electric power steering device also becomes larger, which may restrict the placement of the electric power steering device relative to the vehicle and the placement of peripheral devices of the electric power steering device. Therefore, there is room for improvement in terms of the size of the sensor housing into which the harness connected to the torque sensor is inserted.

[0005] The present disclosure has been made in view of the above, and has an object to provide an electric power steering device that can reduce the size of a sensor housing.

[0006] The electric power steering device of the present disclosure comprises a shaft member that transmits rotational torque, a detection member arranged on the shaft member, a sensor that detects movement of the detection member in a circumferential direction centered on the shaft member, a sensor housing having a bottom portion that intersects the axial direction of the shaft member and through which the shaft member passes, and a wall portion that is arranged around the surface of the bottom portion on which the detection member and the sensor are located, a sensor cover that is attached to the sensor housing from the side of the sensor housing on which the wall portion is located and forms a storage section together with the sensor housing, and a harness that is electrically connected to the sensor, wherein the detection member and the sensor are arranged inside the storage section, the bottom portion of the sensor housing has a through hole through which the harness passes, and the harness is arranged between the inside and outside of the storage section through the through hole.

[0007] With this configuration, when the harness is arranged between the inside and outside of the storage compartment formed by the sensor housing and the sensor cover, the harness can be arranged from the inside of the storage compartment to the outside in the radial direction of the storage compartment. This prevents the overall radial size of the bottom and wall of the sensor housing, including the harness, from increasing due to the harness being arranged from the inside of the storage compartment to the outside in the radial direction of the storage compartment. As a result, the sensor housing can be made more compact.

[0008] In a preferred embodiment, the through hole is adjacent to an inner peripheral surface of the wall portion, and the inner peripheral surface of the wall portion has a recess along the through hole.

[0009] With this configuration, the inner peripheral surface of the wall portion has a recess that aligns with the through hole, so the radial size of the bottom portion and the wall portion can be reduced while still providing a through hole in the bottom portion, thereby enabling the sensor housing to be made more compact.

[0010] In a preferred embodiment, the sensor cover has a groove portion in the portion facing the wall portion of the sensor housing in the axial direction of the shaft member, with the thickness direction of the wall portion being the groove width direction, and the sensor cover is attached to the sensor housing by inserting the wall portion into the groove portion.

[0011] With this configuration, the sensor cover has a groove and is attached to the sensor housing with the wall portion fitting into the groove, which prevents water from entering the storage compartment through the joint between the sensor cover and the sensor housing, thereby ensuring waterproofing of the storage compartment formed by the sensor housing and the sensor cover.

[0012] In a preferred embodiment, an elastic body is disposed in the groove and contacts the wall portion that enters the groove.

[0013] With this configuration, an elastic body that contacts the wall is disposed in the groove of the sensor cover, and when the sensor cover is attached to the sensor housing, the elastic body enhances the waterproofness of the mating portion between the sensor cover and the sensor housing, thereby improving the waterproofness of the storage section.

[0014] In a preferred embodiment, the sensor housing holds a bearing at the bottom and rotatably supports the shaft member via the bearing, and the through hole is disposed between the bearing and the wall portion.

[0015] With this configuration, the through hole is positioned between the bearing and the wall, so when providing the through hole in the bottom, the thickness of the portion of the bottom that receives the load from the bearing can be ensured. This allows the through hole for passing the harness through to be provided in the bottom of the sensor housing while ensuring the rigidity of the bottom against the load from the bearing held by the bottom of the sensor housing, thereby achieving both ensuring the rigidity of the bottom and making the bottom smaller. As a result, the sensor housing can be made smaller.

[0016] In a preferred embodiment, the sensor cover has a wall-facing surface that faces the outer peripheral surface of the wall of the sensor housing, and an elastic body that contacts the sensor cover and the sensor housing is arranged between the wall-facing surface and the outer peripheral surface of the wall.

[0017] With this configuration, by disposing an elastic body that comes into contact with the sensor cover and the sensor housing between the wall-facing surface of the sensor cover and the outer peripheral surface of the wall of the sensor housing, it is possible to prevent water from seeping in from the outside to the inside of the sensor housing by running between the wall-facing surface of the sensor cover and the outer peripheral surface of the wall of the sensor housing, thereby improving the waterproofness of the storage section.

[0018] In a preferred embodiment, the sensor housing has a second bottom on the outside of the wall portion, the sensor cover has a second bottom opposing portion opposing the second bottom, and a liquid sealant is disposed between the second bottom and the second bottom opposing portion.

[0019] According to this configuration, by disposing a liquid sealant between the second bottom of the sensor housing and the second bottom-facing portion of the sensor cover, the area between the second bottom and the second bottom-facing portion can be waterproofed by the sealant. This allows the areas between the sensor housing and the second bottom and between the sensor cover and the second bottom-facing portion to be waterproofed over a wide area by the sealant. As a result, the waterproofness of the storage section can be improved.

[0020] In a preferred embodiment, the second bottom opposing portion has a protrusion that protrudes toward the second bottom, and the protrusion protrudes toward the second bottom further than the portions on both sides of the protrusion in the radial direction of the bottom at the second bottom opposing portion.

[0021] According to this configuration, the second bottom-facing portion of the sensor cover has a protrusion, which makes it possible to make the distance between the second bottom of the sensor housing and the protrusion different from the distance between the portions of the second bottom-facing portion on both sides of the protrusion and the second bottom of the sensor housing. This allows the sealant disposed between the second bottom of the sensor housing and the second bottom-facing portion of the sensor cover to be disposed in three layers: a layer between the second bottom of the sensor housing and the protrusion, and a layer between the portions of the second bottom-facing portion on both sides of the protrusion and the second bottom. Therefore, the three-layer sealant can improve the waterproofness between the second bottom of the sensor housing and the second bottom-facing portion of the sensor cover, thereby improving the waterproofness of the housing.

[0022] The electric power steering device according to the present disclosure has an advantage that the sensor housing can be made smaller.

[0023] FIG. 1 is a schematic diagram of an electric power steering device according to an embodiment. FIG. 2 is a perspective view of a main portion of the electric power steering device according to the embodiment. FIG. 3 is a perspective view of a torque sensor device, a stub shaft, and a pinion gear. FIG. 4 is a perspective view of a main portion of the components of the torque sensor device shown in FIG. 3. FIG. 5 is a schematic view of the torque sensor device and its surroundings in the electric power steering device. FIG. 6 is a perspective view showing a state in which a sensor cover is attached to a sensor housing. FIG. 7 is a perspective view of the sensor housing with the sensor cover shifted toward the side where the stub shaft is located. FIG. 8 is a perspective view of the sensor housing with the sensor cover removed. FIG. 9 is a cross-sectional view taken along the line A-A in FIG. 6. FIG. 10 is a detailed view of portion B in FIG. 9. FIG. 11 is a view taken along the line C-C in FIG. 8 and is a plan view of the bottom of the sensor housing. FIG. 12 is a detailed view of portion D in FIG. 11. FIG. 13 is a cross-sectional view taken along the line E-E in FIG. 8. FIG. 14 is an explanatory view showing a modified example of the electric power steering device according to the embodiment, in which elastic bodies are arranged on both sides of the wall in the thickness direction. Fig. 15 is an explanatory diagram showing a modified example of an electric power steering device according to the embodiment, in which an elastic body is disposed between the wall portion and a wall portion of the sensor cover facing a wall portion facing the outer peripheral surface of the wall portion of the sensor housing. Fig. 16 is an explanatory diagram showing a modified example of an electric power steering device according to the embodiment, in which an elastic body is disposed between the wall portion facing surface of the sensor cover and the wall portion of the sensor housing and spaced apart from the second bottom. Fig. 17 is an explanatory diagram showing a modified example of an electric power steering device according to the embodiment, in which an elastic body and a groove are used in combination to waterproof the gap between the wall portion facing surface of the sensor cover and the wall portion of the sensor housing. Fig. 18 is an explanatory diagram showing a modified example of an electric power steering device according to the embodiment, in which a sealant is disposed between the sensor cover and the sensor housing. Fig. 19 is an explanatory diagram showing a modified example of an electric power steering device according to the embodiment, in which a sealant is disposed between the sensor cover and the sensor housing.

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

[0025] [Embodiment] Fig. 1 is a schematic diagram of an electric power steering device 50 according to an embodiment. As shown in Fig. 1, the electric power steering device 50 includes, in the order in which a force applied by an operator is transmitted, a steering wheel 51, a steering shaft 52, a universal joint 53, a lower shaft 54, a universal joint 55, a stub shaft 57, a steering gear 58, and a tie rod 95. The electric power steering device 50 also includes a control device (hereinafter referred to as an ECU (Electronic Control Unit)) 100, a torque sensor device 10, and an electric motor 102. A vehicle speed sensor 101 is provided in the vehicle and outputs a vehicle speed signal V to the ECU 100 via CAN (Controller Area Network) communication.

[0026] The steering shaft 52 is connected to the steering wheel 51 at one end and to a universal joint 53 at the other end.

[0027] Lower shaft 54 ​​is connected at one end to universal joint 53 and at the other end to universal joint 55. Stub shaft 57 is connected at one end to universal joint 55 and at the other end to torque sensor device 10. Torque sensor device 10 is connected at one end to stub shaft 57 and at the other end to pinion gear 58a of steering gear 58.

[0028] More specifically, the stub shaft 57 and the pinion gear 58a are connected via a torsion bar 59 (see FIG. 5). One end of the torsion bar 59 is connected to the stub shaft 57, and the other end is connected to the pinion gear 58a, and the torsion bar 59 transmits rotational torque between the stub shaft 57 and the pinion gear 58a. The torque sensor device 10 detects the rotational torque transmitted between the stub shaft 57 and the pinion gear 58a via the torsion bar 59. The stub shaft 57 and the pinion gear 58a constitute a shaft member 56 that transmits the rotational torque detected by the torque sensor device 10 according to this embodiment.

[0029] The steering gear 58 includes a pinion gear 58a and a rack bar 58b. The pinion gear 58a is connected to the stub shaft 57 via a torsion bar 59 (see FIG. 5). One end of the pinion gear 58a is connected to the stub shaft 57 via the torsion bar 59, and the other end of the pinion gear 58a is capable of transmitting the driving force of the electric motor 102. The rack bar 58b meshes with the pinion gear 58a. The steering gear 58 converts the rotational motion transmitted to the pinion gear 58a into linear motion by the rack bar 58b. The tie rod 95 is connected to the rack bar 58b. In other words, the electric power steering device 50 is of a rack-and-pinion type.

[0030] 2 is a perspective view of a main portion of the electric power steering device 50 according to the embodiment. The pinion gear 58a is disposed within a sensor housing 60. The rack bar 58b is disposed within a rack housing 90 formed integrally with the sensor housing 60. The sensor housing 60 is formed with a motor mounting portion 91 for mounting an electric motor 102, and the electric motor 102 is mounted to the motor mounting portion 91. The driving force generated by the electric motor 102 can be transmitted to the pinion gear 58a within the sensor housing 60. The torque sensor device 10 is attached to the sensor housing 60 and is coupled to the stub shaft 57 and the pinion gear 58a disposed within the sensor housing 60.

[0031] The torque sensor device 10 detects, as steering torque, the steering force of the driver transmitted to the steering shaft 52 via the steering wheel 51. The vehicle speed sensor 101 detects the traveling speed (vehicle speed) of the vehicle equipped with the electric power steering device 50. The electric motor 102, the torque sensor device 10, and the vehicle speed sensor 101 are electrically connected to the ECU 100.

[0032] The ECU 100 controls the operation of the electric motor 102. The ECU 100 also acquires signals from the torque sensor device 10 and the vehicle speed sensor 101. That is, the ECU 100 acquires the steering torque T from the torque sensor device 10 and the vehicle speed signal V from the vehicle speed sensor 101. When the ignition switch 105 is on, the ECU 100 is supplied with power from a power supply device (e.g., an on-board battery) 106. The ECU 100 calculates an assist steering command value of the assist command based on the steering torque T and the vehicle speed signal V. The ECU 100 then adjusts the power value X to be supplied to the electric motor 102 based on the calculated assist steering command value. The ECU 100 acquires, as operation information Y, information on an induced voltage from the electric motor 102 or information output from a rotation detection device such as a resolver provided in the electric motor 102.

[0033] The steering force of the operator (driver) input to the steering wheel 51 is detected as steering torque T by the torque sensor device 10. The ECU 100 acquires the steering torque T from the torque sensor device 10 and also acquires a vehicle speed signal V from a vehicle speed sensor 101. The ECU 100 then controls the operation of the electric motor 102. The driving force generated by the electric motor 102 is transmitted to the pinion gear 58a as auxiliary steering torque. That is, the steering force of the operator input to the steering wheel 51 is transmitted to the pinion gear 58a from the stub shaft 57 via the torsion bar 59 (see FIG. 5 ), and the auxiliary steering torque is also transmitted from the electric motor 102 to the pinion gear 58a. Because the auxiliary steering torque is transmitted to the pinion gear 58a from the electric motor 102, the force required to operate the steering wheel 51 is reduced.

[0034] The steering force transmitted to the pinion gear 58a is transmitted to the tie rod 95 via the steering gear 58, displacing the wheels.

[0035] 3 is a perspective view of the torque sensor device 10, the stub shaft 57, and the pinion gear 58a. The stub shaft 57 and the pinion gear 58a, which are the shaft members 56 connected to the torque sensor device 10, are connected to the torque sensor device 10 from opposite sides of the torque sensor device 10. In other words, the stub shaft 57 and the pinion gear 58a are disposed on opposite sides of the torque sensor device 10 and extend in opposite directions.

[0036] Of these, the pinion gear 58a is formed with a gear portion 58ag that meshes with teeth (not shown) formed on the rack bar 58b. Furthermore, the pinion gear 58a is formed with a spline 58as at an end opposite to the end connected to the torque sensor device 10, to which a worm wheel 102b (see FIG. 5) that meshes with a worm gear 102a (see FIG. 5) attached to the output shaft of the electric motor 102 is attached. As a result, auxiliary steering torque from the electric motor 102 is transmitted to the pinion gear 58a via the worm gear 102a and the worm wheel 102b.

[0037] FIG. 4 is a perspective view of essential components of the torque sensor device 10 shown in FIG. 3 . FIG. 5 is a schematic diagram of the torque sensor device 10 and its surroundings in an electric power steering system 50. The torque sensor device 10 includes a detection member 20 disposed on a shaft member 56 and a sensor that detects movement of the detection member 20 in the circumferential direction about the shaft member 56. More specifically, the torque sensor device 10 includes an input rotor 21 and an output rotor 31 that are equipped with the detection member 20 and attached to the shaft member 56. The input rotor 21 is attached to the input shaft, which is one of the shaft members 56 connected to the torque sensor device 10, and the output rotor 31 is attached to the output shaft, which is the other of the shaft members 56. In this embodiment, the input shaft is a stub shaft 57, and the input rotor 21 is attached to the stub shaft 57. The output shaft is a pinion gear 58a, and the output rotor 31 is attached to the pinion gear 58a.

[0038] The sensor is also arranged on a printed circuit board 15 of the torque sensor device 10, and a torque sensor 16, which is a sensor that detects the movement of the input rotor 21 and the output rotor 31 in the circumferential direction around the shaft member 56, is arranged on the printed circuit board 15.

[0039] The input rotor 21 has a cylindrical sleeve 22 formed in a substantially cylindrical shape, and a vane-shaped member 25 serving as the detection member 20 arranged around the cylindrical sleeve 22. The cylindrical sleeve 22 is made of a metal material, and its inner diameter is approximately the same as the outer diameter of the stub shaft 57 at the position where the input rotor 21 is attached. Therefore, the input rotor 21 is attached to the stub shaft 57 by press-fitting the stub shaft 57 into the cylindrical sleeve 22.

[0040] The blade-shaped member 25 is a thin plate-like member made of a metal material, and is arranged around the cylindrical sleeve 22 with the thickness direction of the plate oriented in the axial direction of the cylindrical sleeve 22. The blade-shaped member 25 has a plurality of blades spaced apart from one another in the circumferential direction of the cylindrical sleeve 22, and is formed by arranging the plurality of blades around the cylindrical sleeve 22 with the thickness direction of each blade oriented in the axial direction of the cylindrical sleeve 22. The cylindrical sleeve 22 and the blade-shaped member 25 are integrally formed by a resin mold 23 made of a resin material. In other words, the blade-shaped member 25 is arranged around the cylindrical sleeve 22 by the resin mold 23.

[0041] The vane-shaped member 25, which is the detection member 20 of the input rotor 21, is disposed near one end of the input rotor 21 in the axial direction of the cylindrical sleeve 22. The input rotor 21 is attached to the stub shaft 57 with the side on which the vane-shaped member 25 is disposed facing the side on which the output rotor 31 is located.

[0042] The output rotor 31 has a sleeve portion 32 formed in a substantially cylindrical shape, and a vane-shaped member 35 serving as the detection member 20 that is disposed around the sleeve portion 32. The sleeve portion 32 is made of a metal material, and its inner diameter is approximately the same as the outer diameter of the pinion gear 58a at the position where the output rotor 31 is attached. Therefore, the output rotor 31 is attached to the pinion gear 58a by press-fitting the pinion gear 58a into the sleeve portion 32.

[0043] The blade-shaped member 35 is a thin plate-like member made of a metal material, and is arranged around the sleeve portion 32 with the thickness direction of the plate oriented in the axial direction of the sleeve portion 32. The blade-shaped member 35 has a plurality of blades spaced apart from one another in the circumferential direction of the sleeve portion 32, and is formed by arranging the plurality of blades around the sleeve portion 32 with the thickness direction of each blade oriented in the axial direction of the sleeve portion 32.

[0044] The vane-shaped members 35, which are the detection member 20 of the output rotor 31, and the vane-shaped members 25 of the input rotor 21 are different in the circumferential size of each vane and the circumferential spacing between the vanes. In this embodiment, the vane-shaped members 35 of the output rotor 31 are larger in circumferential size and the circumferential spacing between the vanes are also larger than those of the vane-shaped members 25 of the input rotor 21. Unlike the input rotor 21, the sleeve portion 32 and the vane-shaped members 35 of the output rotor 31 are integrally formed as a single member made of a metal material.

[0045] The vane-shaped members 35 of the output rotor 31 are disposed near one end of the output rotor 31 in the axial direction of the sleeve portion 32. The output rotor 31 is attached to the pinion gear 58a in such a manner that the side on which the vane-shaped members 35 are disposed faces the side on which the input rotor 21 is located.

[0046] The printed circuit board 15 is disposed between the input rotor 21 and the output rotor 31. A torque sensor 16, which is a sensor including a detection coil that detects the movement of the blade-shaped members 25 of the input rotor 21 in the circumferential direction centered on the stub shaft 57 and the movement of the blade-shaped members 35 of the output rotor 31 in the circumferential direction centered on the pinion gear 58 a, is mounted on the printed circuit board 15. The torque sensor 16 is disposed in a position facing the blade-shaped members 25 of the input rotor 21 and the blade-shaped members 35 of the output rotor 31.

[0047] The torque sensor 16 is configured so that its inductance changes when the relative circumferential position of the vane-shaped members 25 of the input rotor 21 and the vane-shaped members 35 of the output rotor 31 changes. The torque sensor 16 arranged on the printed circuit board 15 has a calculation IC that calculates the relative circumferential displacement of the vane-shaped members 25 of the input rotor 21 and the vane-shaped members 35 of the output rotor 31 based on the change in inductance around the detection coil.

[0048] Rotational torque is transmitted between the stub shaft 57, to which the input rotor 21 is attached, and the pinion gear 58a, to which the output rotor 31 is attached, via the torsion bar 59. When the rotational torque is transmitted, the torsion bar 59 twists slightly, slightly changing the relative angle between the stub shaft 57 and the pinion gear 58a in the circumferential direction. The inductance around the detection coil of the torque sensor 16 mounted on the printed circuit board 15 changes when the relative angle between the stub shaft 57 and the pinion gear 58a changes. The torque sensor 16 detects the relative angle between the stub shaft 57 and the pinion gear 58a from the change in inductance around the detection coil, thereby detecting the rotational torque. This allows the torque sensor device 10 to detect the rotational torque transmitted between the stub shaft 57 and the pinion gear 58a.

[0049] The torque sensor device 10 according to this embodiment also includes an initial gear 40 for detecting the steering angle, which is the rotation angle of the shaft member 56, a sensor gear 41, a magnet 42, and a steering angle sensor 17. The initial gear 40 is disposed on the stub shaft 57, and has a gear on its outer periphery. Therefore, the initial gear 40 rotates integrally with the stub shaft 57 as the stub shaft 57 rotates.

[0050] The sensor gear 41 is a gear that meshes with the gear on the outer periphery of the initial gear 40, and is disposed so that its rotation axis is parallel to the rotation axes of the stub shaft 57 and the sensor gear 41. Because the sensor gear 41 meshes with the initial gear 40, the rotation of the initial gear 40, which rotates together with the stub shaft 57, is transmitted to the sensor gear 41, allowing it to rotate. The magnet 42 is disposed on the sensor gear 41, and rotates integrally with the sensor gear 41 when the sensor gear 41 rotates. The magnet 42 is magnetized on its outer periphery with alternating south and north poles.

[0051] The steering angle sensor 17 is mounted on the printed circuit board 15, similar to the torque sensor 16. The steering angle sensor 17 is a sensor that detects the movement of the initial gear 40 in the circumferential direction around the shaft member 56, and is able to detect the steering angle of the shaft member 56 by detecting the movement of the initial gear 40 via the sensor gear 41 and the magnet 42. In other words, the initial gear 40 arranged on the stub shaft 57 is provided as a detection member that is the detection target of the steering angle sensor 17.

[0052] When the stub shaft 57 rotates, the initial gear 40 rotates together with the stub shaft 57, and the rotation of the initial gear 40 is transmitted to the sensor gear 41, causing the sensor gear 41 to also rotate. When the sensor gear 41 rotates, the magnet 42 also rotates, so the steering angle sensor 17 detects the change in magnetic flux of the rotating magnet 42 to detect the rotation angle of the sensor gear 41. The rotation angle of the sensor gear 41 is converted into the rotation angle of the initial gear 40 based on the gear ratio between the initial gear 40 and the sensor gear 41, thereby determining the absolute rotation angle of the stub shaft 57 on which the sensor gear 41 is disposed. In this way, the torque sensor device 10 can detect the absolute steering angle of the stub shaft 57, which is the shaft member 56.

[0053] A harness 82 (see FIG. 2) is electrically connected to the torque sensor 16 and the steering angle sensor 17 of the torque sensor device 10, which are capable of detecting the rotational torque and steering angle of the shaft member 56. One end of the harness 82 is connected to the printed circuit board 15 on which the torque sensor 16 and the steering angle sensor 17 are mounted, and the other end is connected to the ECU 100, which is disposed integrally with the electric motor 102.

[0054] Fig. 6 is a perspective view showing the sensor housing 60 with the sensor cover 70 attached. Fig. 7 is a perspective view of the sensor housing 60 with the sensor cover 70 shifted toward the side where the stub shaft 57 is located. Fig. 8 is a perspective view of the sensor housing 60 with the sensor cover 70 removed. The sensor cover 70 can be attached to the sensor housing 60, and the detecting member 20, torque sensor 16, steering angle sensor 17, initial gear 40, sensor gear 41, and magnet 42 of the torque sensor device 10 are disposed inside an accommodating portion 80 formed by the sensor housing 60 and the sensor cover 70.

[0055] In detail, the printed circuit board 15 on which the torque sensor 16 and the steering angle sensor 17 are mounted, and the input side rotor 21 having the blade-shaped member 25 which is the detection member 20 are covered by the sensor case 11, and the input side rotor 21 and the printed circuit board 15 are arranged inside the storage section 80 while covered by the sensor case 11.

[0056] The sensor housing 60 has a bottom 61 that intersects the axial direction of the shaft member 56 and through which the shaft member 56 passes, and a wall 65 that is disposed around the bottom 61. The bottom 61 is formed in a substantially circular shape, and the wall 65 is disposed near the outer periphery of the bottom 61. Therefore, the bottom 61 and the wall 65 are formed in the shape of a low, substantially cylindrical cylinder with a bottom.

[0057] The shaft member 56 passes through the bottom portion 61, and the bottom portion 61 is disposed in an orientation and position such that the axial direction of the shaft member 56 is perpendicular to the bottom portion 61 and the center of the circle that is the shape of the bottom portion 61 coincides with the axial center of the shaft member 56. The bottom portion 61 of the sensor housing 60 is disposed near the torque sensor device 10 and on the side of the torque sensor device 10 where the pinion gear 58a is located in the axial direction of the shaft member 56.

[0058] The wall portion 65 arranged around the bottom portion 61 is arranged around the surface of the bottom portion 61 on the side where the detection member 20, the torque sensor 16, and the steering angle sensor 17 of the torque sensor device 10 are located. In other words, the wall portion 65 stands upright relative to the bottom portion 61 toward the side where the torque sensor device 10 is located in the axial direction of the shaft member 56.

[0059] The sensor cover 70 is attached to the sensor housing 60 from the side where the wall 65 is located, of the sensor housing 60, which has the bottom 61 and the wall 65. As a result, the sensor cover 70 forms an accommodation section 80 together with the sensor housing 60. The sensor cover 70 has a main body 71 that is cylindrical in shape and has a diameter approximately the same as the diameter of the bottom 61 of the sensor housing 60, and a tubular section 72 that is cylindrical in shape and has a smaller diameter than the main body 71. The tubular section 72 is disposed on one end side of the main body 71, with its central axis aligned with the central axis of the main body 71.

[0060] The end of the main body 71 on the side where the cylindrical portion 72 is located is closed, with a portion between the outer peripheral surface of the main body 71 and the outer peripheral surface of the cylindrical portion 72, and a plurality of ribs 73 are arranged between the outer peripheral surface of the cylindrical portion 72 and the closed portion of the main body 71. A portion of the main body 71 of the sensor cover 70 opposite the portion where the cylindrical portion 72 is located and a portion of the cylindrical portion 72 opposite the portion where the main body 71 is located are each open, and the main body 71 and the cylindrical portion 72 are communicated at their inner portions. A plurality of mounting portions 74 are arranged around the periphery of the main body 71 for mounting the sensor cover 70 to the sensor housing 60. The mounting portions 74 have through holes formed therein for passing mounting bolts 75 therethrough.

[0061] When attaching the sensor cover 70 to the sensor housing 60, the portion of the main body 71 opposite the portion where the cylindrical portion 72 is located is positioned facing the surface of the bottom 61 of the sensor housing 60 where the wall portion 65 is located. The sensor cover 70 is attached to the bottom 61 in this orientation from the wall portion 65 side, and the mounting bolt 75 is passed through a through hole formed in the mounting portion 74 and screwed into a threaded hole formed in the sensor housing 60. At this time, the stub shaft 57 is passed through an opening in the cylindrical portion 72 of the sensor cover 70 on the side opposite the side where the main body portion 71 is located.

[0062] Figure 9 is a cross-sectional view taken along line A-A in Figure 6. Figure 10 is a detailed view of part B in Figure 9. A seal member 88 is disposed inside the cylindrical portion 72 of the sensor cover 70. The seal member 88 is disposed near the end of the cylindrical portion 72 of the sensor cover 70 opposite the side where the main body portion 71 is located. The seal member 88 contacts the steering gear 58, which is the shaft member 56 located inside the cylindrical portion 72. This ensures sealing between the sensor cover 70 and the shaft member 56 at the end of the cylindrical portion 72 opposite the side where the main body portion 71 is located.

[0063] The sensor cover 70 attached to the sensor housing 60 has a groove 76 whose width direction is the thickness direction of the wall 65 in the portion facing the wall 65 of the sensor housing 60 in the axial direction of the shaft member 56. That is, the groove 76 of the sensor cover 70 is formed in a circular shape with a diameter approximately the same as the diameter of the wall 65 of the sensor housing 60.

[0064] The groove 76 of the sensor cover 70 opens toward the side where the wall 65 of the sensor housing 60 is located, and has a groove width that is slightly larger than the thickness of the wall 65. The groove depth of the groove 76 is slightly larger than the height of the wall 65. When attaching the sensor cover 70 to the sensor housing 60, the sensor cover 70 is attached to the sensor housing 60 by fitting the wall 65 of the sensor housing 60 into the groove 76 thus formed.

[0065] The wall portion 65 that fits into the groove portion 76 has an outer peripheral surface 68, which is the side surface on the outer periphery in the radial direction of the wall portion 65, facing an outer groove wall 76a, which is the groove wall that is located on the outer side in the radial direction of the pair of groove walls of the groove portion 76, and an inner peripheral surface 66, which is the side surface on the inner periphery of the wall portion 65, facing an inner groove wall 76b, which is the groove wall that is located on the inner side in the radial direction of the pair of groove walls of the groove portion 76. Because the groove width of the groove portion 76 is slightly larger than the thickness of the wall portion 65, for example, one of the opposing outer peripheral surface 68 of the wall portion 65 and the outer groove wall 76a of the groove portion 76, and the inner peripheral surface 66 of the wall portion 65 and the inner groove wall 76b of the groove portion 76 are in contact with each other and are slightly separated by a small gap.

[0066] Furthermore, because the depth of the groove 76 is slightly greater than the height of the wall 65, the tip 69, which is the end of the wall 65 opposite the side where the sensor housing 60 is located, is slightly separated by a small gap from the groove bottom 76c, which is located on the side of the groove 76 opposite the side where the sensor housing 60 is located. The wall 65 fits into the inside of the groove 76 in this relative relationship with respect to the groove 76.

[0067] An elastic body 78 is disposed in the groove 76 of the sensor cover 70 and contacts the wall 65 of the sensor housing 60 that fits into the groove 76. An O-ring made of a resilient rubber material, for example, is used as the elastic body 78. More specifically, an elastic body holding portion 77, which is a recess in which the elastic body 78 can be disposed, is formed adjacent to the opening of the groove 76 of the sensor cover 70.

[0068] The elastic body holding portion 77 is disposed adjacent to the groove portion 76 on the side where the outer groove wall 76a of the groove portion 76 is located, and is formed around the entire circumference of the groove portion 76. In other words, the elastic body holding portion 77 is formed adjacent to the groove portion 76 on the opening side of the groove portion 76 in the outer groove wall 76a of the groove portion 76. The elastic body 78 disposed in the elastic body holding portion 77 comes into contact with both the sensor cover 70 and the sensor housing 60 when the sensor cover 70 is attached to the sensor housing 60.

[0069] The sensor cover 70 is attached to the sensor housing 60 by placing the wall 65 of the sensor housing 60 inside the groove 76 with the elastic body 78 placed in the elastic body holding portion 77. The elastic body 78 placed in the elastic body holding portion 77 comes into contact with the wall 65 of the sensor housing 60 that has entered the groove 76 of the sensor cover 70, thereby coming into contact with both the sensor cover 70 and the sensor housing 60. The sensor cover 70 is fixed to the sensor housing 60 using mounting bolts 75 in a state where the sensor cover 70 is attached to the sensor housing 60 with the wall 65 of the sensor housing 60 entering the groove 76 of the sensor cover 70.

[0070] By attaching the sensor cover 70 to the sensor housing 60 in this manner, the bottom 61 and wall 65 of the sensor housing 60 and the sensor cover 70 form an accommodating section 80. That is, the inner circumferential surfaces of the bottom 61 and wall 65 of the sensor housing 60 and the inner circumferential surfaces of the main body 71 and cylindrical section 72 of the sensor cover 70 form the accommodating section 80, which is a space separated from the outside of the sensor housing 60 and the sensor cover 70. The torque sensor device 10 is disposed inside the accommodating section 80, which is a space formed by the sensor housing 60 and the sensor cover 70 in this manner.

[0071] One end of the harness 82 is connected to the torque sensor device 10 arranged inside the accommodating portion 80, and the other end is connected to the ECU 100 arranged integrally with the electric motor 102. For this reason, the bottom 61 of the sensor housing 60 has a through-hole 62 through which the harness 82 passes, and the harness 82 is arranged between the inside and outside of the accommodating portion 80 through the through-hole 62 formed in the bottom 61.

[0072] In other words, with the sensor cover 70 attached to the sensor housing 60, the harness 82 is arranged from the inside of the accommodation portion 80 formed by the sensor housing 60 and the sensor cover 70 through the through-hole 62 in the bottom portion 61 to the outside of the accommodation portion 80. One end of the harness 82 is connected to the torque sensor device 10 inside the accommodation portion 80, and the other end is connected to the ECU 100 outside the accommodation portion 80.

[0073] FIG. 11 is a view taken along the arrows CC in FIG. 8 and is a plan view of the bottom 61 of the sensor housing 60. FIG. 12 is a detailed view of portion D in FIG. 11 . Note that FIGS. 11 and 12 omit the illustration of the torque sensor device 10 and the harness 82 disposed inside the accommodation portion 80. The through hole 62 formed in the bottom 61 of the sensor housing 60 is adjacent to the inner circumferential surface 66 of the wall portion 65. The inner circumferential surface 66 of the wall portion 65 has a recess 67 along the through hole 62. That is, the through hole 62 formed in the bottom 61 of the sensor housing 60 is formed in a position where it slightly interferes with or slightly penetrates the wall portion 65 disposed near the outer periphery of the bottom 61. Therefore, in the portion of the inner circumferential surface 66 of the wall portion 65 where the through hole 62 is adjacent and interferes, a recess 67 is formed that is recessed radially outward of the bottom 61 along the through hole 62.

[0074] 13 is a cross-sectional view taken along the line E-E of FIG. 8. The harness 82 passing through a through hole 62 formed in the bottom 61 of the sensor housing 60 is attached to the through hole 62 by an attachment member 83. The attachment member 83 is formed in a generally cylindrical shape with an outer diameter approximately the same as the inner diameter of the through hole 62 and a portion capable of blocking the through hole 62, and is disposed at the portion of the harness 82 that passes through the through hole 62. The harness 82 passing through the through hole 62 is attached to the inside of the through hole 62 by inserting the attachment member 83 into the through hole 62. This restricts relative movement of the harness 82 passing through the through hole 62 with respect to the through hole 62, and the attachment member 83 blocks the portion between the through hole 62 and the harness 82.

[0075] The sensor housing 60 holds a bearing 85 that supports the shaft member 56 at the bottom 61. Therefore, the sensor housing 60 not only holds the bearing 85 at the bottom 61 but also rotatably supports the shaft member 56 via the bearing 85. More specifically, the sensor housing 60 has a bearing holder 63 that is a hole that opens along the axial direction of the shaft member 56 near the center of the bottom 61, and the sensor housing 60 holds the bearing 85 at the bearing holder 63. The bearing 85 held by the bearing holder 63 formed on the bottom 61 rotatably supports the pinion gear 58 a of the shaft member 56. As a result, the sensor housing 60 rotatably supports the pinion gear 58 a via the bearing 85 held at the bottom 61.

[0076] The through hole 62 formed in the bottom 61 of the sensor housing 60 is disposed between the wall portion 65 and the bearing 85 held by the bearing holder 63. The portion of the sensor housing 60 between the bearing holder 63 and the through hole 62 also receives the load acting on the bearing 85 from the pinion gear 58 a. Therefore, the portion of the sensor housing 60 between the bearing holder 63 and the through hole 62 needs to be strong enough to withstand the load acting on the bearing 85. In this embodiment, the through hole 62 formed in the bottom 61 of the sensor housing 60 is disposed radially outward of the bottom 61, thereby increasing the distance between the through hole 62 and the bearing holder 63, thereby ensuring the strength of the portion of the sensor housing 60 between the bearing holder 63 and the through hole 62.

[0077] As described above, in the electric power steering device 50 according to this embodiment, the detection members 20 of the input rotor 21 and the output rotor 31, the torque sensor 16, and the steering angle sensor 17 are disposed inside the accommodation portion 80 formed by the sensor housing 60 and the sensor cover 70. The torque sensor 16 and the steering angle sensor 17 disposed inside the accommodation portion 80 in this manner are electrically connected to the harness 82, and a through-hole 62 through which the harness 82 passes is formed in the bottom 61 of the sensor housing 60. Therefore, the harness 82 electrically connected to the torque sensor 16 and the steering angle sensor 17 inside the accommodation portion 80 passes through the through-hole 62 formed in the bottom 61 of the sensor housing 60 and is disposed across the inside and outside of the accommodation portion 80.

[0078] As a result, when arranging the harness 82 across the inside and outside of the accommodation section 80 formed by the sensor housing 60 and the sensor cover 70, the harness 82 can be arranged from the inside of the accommodation section 80 without being directed radially outward of the accommodation section 80. Therefore, it is possible to prevent the overall radial size of the bottom 61 and wall 65 of the sensor housing 60, including the harness 82, from increasing, which would be caused by the harness 82 being arranged from the inside of the accommodation section 80 toward the radially outward of the accommodation section 80. As a result, the sensor housing 60 can be made more compact.

[0079] Furthermore, the through-hole 62 formed in the bottom 61 of the sensor housing 60 is adjacent to the inner circumferential surface 66 of the wall 65, and the inner circumferential surface 66 of the wall 65 has a recess 67 that is aligned with the through-hole 62. This allows the radial size of the bottom 61 and the wall 65 to be reduced while still providing the through-hole 62 in the bottom 61. As a result, the sensor housing 60 can be made more compact.

[0080] Furthermore, the sensor cover 70 has a groove 76 at a portion facing the wall 65 of the sensor housing 60, and is attached to the sensor housing 60 by fitting the wall 65 into the groove 76, thereby preventing water from entering the accommodation portion 80 through the joint between the sensor cover 70 and the sensor housing 60. As a result, the accommodation portion 80 formed by the sensor housing 60 and the sensor cover 70 and in which the torque sensor device 10 is disposed can be made waterproof.

[0081] Furthermore, since an elastic body 78 is disposed in the groove 76 of the sensor cover 70 and contacts the wall 65 that fits into the groove 76, the elastic body 78 can improve the waterproofness of the joint between the sensor cover 70 and the sensor housing 60 when the sensor cover 70 is attached to the sensor housing 60. As a result, the waterproofness of the accommodation section 80 can be improved.

[0082] Furthermore, the sensor housing 60 rotatably supports the shaft member 56 at the bottom 61 via the bearing 85, and the through hole 62 is disposed between the bearing 85 and the wall portion 65, so that when the through hole 62 is provided in the bottom 61, the thickness of the portion of the bottom 61 that receives the load from the bearing 85 can be ensured. This allows the through hole 62 for passing the harness 82 to be provided in the bottom 61 of the sensor housing 60 while ensuring the rigidity of the bottom 61 against the load received from the bearing 85 held by the bottom 61 of the sensor housing 60, and therefore it is possible to both ensure the rigidity of the bottom 61 and reduce the size of the bottom 61. As a result, the sensor housing 60 can be reduced in size.

[0083] [Variations] In the above-described embodiment, the elastic body 78 arranged at the position of the groove portion 76 of the sensor cover 70 is arranged on the outer peripheral surface 68 side of the wall portion 65 of the sensor housing 60, but the elastic body 78 may be arranged at a position other than this.

[0084] 14 is an explanatory diagram showing a modified example of the electric power steering device 50 according to the embodiment, in which elastic bodies 78 are arranged on both sides in the thickness direction of the wall portion 65. The elastic bodies 78 arranged at the position of the groove portion 76 of the sensor cover 70 may be arranged on both sides in the groove width direction of the groove portion 76, as shown in FIG. 14 , for example, so that the elastic bodies 78 contact the wall portion 65 of the sensor housing 60 from both sides in the thickness direction of the wall portion 65. In other words, the elastic body holders 77 on which the elastic bodies 78 are arranged may be arranged adjacent to the groove portion 76 on both sides of the outer groove wall 76 a and the inner groove wall 76 b of the groove portion 76, and the elastic bodies 78 may be arranged in the elastic body holders 77 on both sides of the outer groove wall 76 a and the inner groove wall 76 b of the groove portion 76.

[0085] As a result, the elastic bodies 78 are arranged so that the elastic bodies 78 contact the inner circumferential surface 66 of the wall portion 65 of the sensor housing 60 and the elastic bodies 78 contact the outer circumferential surface 68, thereby further improving the waterproofness of the joint between the sensor cover 70 and the sensor housing 60. As a result, the waterproofness of the accommodation portion 80 can be further improved.

[0086] Furthermore, in the above-described embodiment, the sensor cover 70 has a groove portion 76, and the sensor cover 70 is attached to the sensor housing 60 by the wall portion 65 of the sensor housing 60 fitting into the groove portion 76, but the sensor cover 70 may also be attached to the sensor housing 60 in other ways.

[0087] 15 is an explanatory diagram showing a modified example of the electric power steering device 50 according to the embodiment, in which an elastic body 78 is disposed between a wall portion-facing surface 171 of a sensor cover 70 that faces the outer peripheral surface 68 of the wall portion 65 of the sensor housing 60 and the wall portion 65. For example, as shown in FIG. 15 , the sensor cover 70 may have a wall portion-facing surface 171 that faces the outer peripheral surface 68 of the wall portion 65 of the sensor housing 60, and an elastic body 78 that comes into contact with the sensor cover 70 and the sensor housing 60 may be disposed between the wall portion-facing surface 171 of the sensor cover 70 and the outer peripheral surface 68 of the wall portion 65 of the sensor housing 60.

[0088] 15 , when the sensor cover 70 is attached to the sensor housing 60, the sensor cover 70 has a wall-facing surface 171 that faces the outer peripheral surface 68 of the wall 65 of the sensor housing 60 from the outside in the radial direction of the wall 65. The wall-facing surface 171 of the sensor cover 70 is formed as a surface that faces inward in the radial direction, and has an inner diameter that is slightly larger than the outer diameter of the wall 65 of the sensor housing 60. As a result, when the sensor cover 70 is attached to the sensor housing 60, the wall-facing surface 171 is positioned to cover the outer peripheral surface 68 of the wall 65 from the outside in the radial direction.

[0089] The elastic body 78 disposed between the wall-facing surface 171 of the sensor cover 70 and the outer peripheral surface 68 of the wall 65 of the sensor housing 60 may be disposed at a base position of the wall 65 relative to the bottom 61, as shown in Fig. 15 . In this case, specifically, the sensor housing 60 has a second bottom 161 formed radially outward of the wall 65 in a direction perpendicular to the axial direction of the shaft member 56, similar to the bottom 61. The wall 65 has a groove-shaped elastic body holding portion 68a recessed from the outer peripheral surface 68 at an end of the outer peripheral surface 68 on the second bottom 161 side. The sensor cover 70 also has a notch-shaped elastic body holding portion 172 recessed from the wall-facing surface 171 at a position on the wall-facing surface 171 facing the elastic body holding portion 68a of the wall 65 of the sensor housing 60.

[0090] The elastic body 78 may be disposed and held in a space defined by the elastic body holding portion 68a of the wall portion 65 of the sensor housing 60 formed as described above and the elastic body holding portion 172 of the wall-facing surface 171 of the sensor cover 70. In this way, the elastic body 78 is held by the elastic body holding portion 68a of the wall portion 65 of the sensor housing 60 and the elastic body holding portion 172 of the wall-facing surface 171 of the sensor cover 70, and the elastic body 78 comes into contact with both the sensor housing 60 and the sensor cover 70, thereby preventing water from entering the inside of the sensor housing 60 from the outside of the wall portion 65.

[0091] In other words, by disposing the elastic body 78, which comes into contact with the sensor cover 70 and the sensor housing 60, between the wall-facing surface 171 of the sensor cover 70 and the outer peripheral surface 68 of the wall 65 of the sensor housing 60, it is possible to prevent water from seeping in from the outside to the inside of the sensor housing 60 by running between the wall-facing surface 171 of the sensor cover 70 and the outer peripheral surface 68 of the wall 65 of the sensor housing 60. This improves the waterproofness of the accommodation section 80.

[0092] Furthermore, when arranging the elastic body 78 between the wall-facing surface 171 of the sensor cover 70 and the wall 65 of the sensor housing 60, it may be arranged in a form other than the form shown in Fig. 15. Fig. 16 is a modified example of the electric power steering device 50 according to the embodiment, and is an explanatory diagram showing a form in which the elastic body 78 between the wall-facing surface 171 of the sensor cover 70 and the wall 65 of the sensor housing 60 is arranged spaced apart from the second bottom 161. The elastic body 78 arranged between the wall-facing surface 171 of the sensor cover 70 and the wall 65 of the sensor housing 60 may be arranged spaced apart from the second bottom 161 of the sensor housing 60, for example, as shown in Fig. 16.

[0093] In this case, the elastic body holding portion 68a formed on the outer peripheral surface 68 of the wall portion 65 of the sensor housing 60 is formed away from the second bottom 161 toward the tip portion 69 of the wall portion 65 as shown in Figure 16, and the elastic body 78 is held by the elastic body holding portion 68a of the wall portion 65 of the sensor housing 60 that is away from the second bottom 161 and the elastic body holding portion 172 of the wall portion opposing surface 171 of the sensor cover 70.

[0094] This allows the elastic body 78, which contacts both the sensor housing 60 and the sensor cover 70, to be positioned away from the second bottom 161 of the sensor housing 60 toward the tip 69 of the wall 65. Therefore, the elastic body 78 can be positioned closer to the downstream side of the second bottom 161 in the path of water infiltration from the outside of the wall 65 to the inside of the sensor housing 60, and the waterproofing provided by the elastic body 78 can be effectively improved.

[0095] In other words, water that penetrates from the outside of the sensor housing 60 into the inside of the sensor housing 60 flows from the second bottom 161 side, between the outer peripheral surface 68 of the wall 65 and the wall-facing surface 171 of the sensor cover 70, toward the tip 69 of the wall 65, and then penetrates into the inside of the sensor housing 60 from the tip 69 side of the wall 65. Therefore, by arranging the elastic body 78 at a position spaced apart from the second bottom 161 toward the tip 69 of the wall 65, the elastic body 78 can suppress water penetration at a position halfway between the second bottom 161 and the tip 69 of the wall 65 in the water penetration path into the inside of the sensor housing 60. Therefore, the waterproofness provided by the elastic body 78 can be effectively enhanced, and the waterproofness of the accommodation portion 80 can be improved.

[0096] Furthermore, when the elastic body 78 is used to ensure waterproofing between the wall-facing surface 171 of the sensor cover 70 and the wall 65 of the sensor housing 60, a configuration other than the elastic body 78 may be used in combination. Fig. 17 is a modified example of the electric power steering device 50 according to the embodiment, and is an explanatory diagram of a configuration in which the elastic body 78 and the groove 68b are used in combination to waterproof the gap between the wall-facing surface 171 of the sensor cover 70 and the wall 65 of the sensor housing 60. The wall 65 of the sensor housing 60 may be provided with a groove 68b formed around the entire circumference of the wall 65 on the outer circumferential surface 68 closer to the tip 69 of the wall 65 than the elastic body holding portion 68a for disposing the elastic body 78.

[0097] In this case, the elastic body 78 is held by an elastic body holder 68a formed on the outer peripheral surface 68 of the wall portion 65 of the sensor housing 60 near the second bottom 161, and an elastic body holder 172 formed on the wall portion-facing surface 171 of the sensor cover 70 at a portion facing the elastic body holder 68a of the sensor housing 60. In this way, by providing the groove 68b on the outer peripheral surface 68 of the wall portion 65 closer to the tip portion 69 than the elastic body 78 arranged between the outer peripheral surface 68 of the wall portion 65 of the sensor housing 60 and the wall portion-facing surface 171 of the sensor cover 70, the elastic body 78 and the groove 68b can prevent water from entering the inside of the sensor housing 60.

[0098] In other words, by providing groove 68b in a portion of wall 65 closer to tip 69 than the position where elastic body 78 is disposed, the shape of outer peripheral surface 68 of wall 65 can be formed into a so-called labyrinth shape, which allows the distance between wall 65 and wall-facing surface 171 of sensor cover 70 to be changed. This allows water that seeps into the gap between outer peripheral surface 68 of wall 65 of sensor housing 60 and wall-facing surface 171 of sensor cover 70 and enters the tip 69 side of wall 65 beyond elastic body 78 to be received by groove 68b. Therefore, both elastic body 78 and groove 68b can prevent water from seeping into the sensor housing 60, improving the waterproofness of accommodating section 80.

[0099] Furthermore, in the above-described embodiment, the elastic body 78 is used to waterproof the accommodation portion 80, but something other than the elastic body 78 may be used to waterproof the accommodation portion 80. FIG. 18 is a modified example of the electric power steering device 50 according to the embodiment, and is an explanatory diagram showing a configuration in which a sealant 180 is disposed between the sensor cover 70 and the sensor housing 60. FIG. 19 is a modified example of the electric power steering device 50 according to the embodiment, and is an explanatory diagram showing a state in which the sealant 180 is disposed between the sensor cover 70 and the sensor housing 60. As shown in FIGS. 18 and 19 , the sealant 180 may be disposed in liquid form between the sensor cover 70 and the sensor housing 60, thereby ensuring waterproofing. The liquid sealant 180 is applied in liquid form when applied to a desired location, and as it dries over time, it becomes less likely to deform and exhibits a tight seal.

[0100] When ensuring waterproofness using liquid sealant 180, liquid sealant 180 is disposed, for example, between second bottom facing portion 175 of sensor cover 70, which is a portion facing second bottom 161 of sensor housing 60, and second bottom 161 of sensor housing 60. As shown in FIG. 18 , by attaching sensor cover 70 to sensor housing 60 while liquid sealant 180 is disposed on second bottom 161 of sensor housing 60, liquid sealant 180 is sandwiched and spread between second bottom facing portion 175 of sensor cover 70 and second bottom 161 of sensor housing 60. As a result, liquid sealant 180 is disposed over a wide range between second bottom 161 of sensor housing 60 and second bottom facing portion 175 of sensor cover 70, as shown in FIG. 19 .

[0101] 18 and 19 , the second bottom facing portion 175 of the sensor cover 70 preferably has a protrusion 176 that protrudes toward the second bottom 161 of the sensor housing 60. In this case, the protrusion 176 of the second bottom facing portion 175 of the sensor cover 70 is formed to protrude further toward the second bottom 161 in the radial direction of the bottom 61 of the sensor housing 60 than both sides of the protrusion 176 in the second bottom facing portion 175. In other words, the distance between the protrusion 176 of the second bottom facing portion 175 of the sensor cover 70 and the second bottom 161 of the sensor housing 60 is smaller than the distance between the both sides of the protrusion 176 in the second bottom facing portion 175 and the second bottom 161.

[0102] Therefore, the sealant 180 located between the second bottom facing portion 175 of the sensor cover 70 and the second bottom 161 of the sensor housing 60 is more reliably spread by the protruding portion 176 of the second bottom facing portion 175, and is disposed over a wide range between the second bottom facing portion 175 of the sensor cover 70 and the second bottom 161 of the sensor housing 60. In other words, the sealant 180 is disposed between the protruding portion 176 of the second bottom facing portion 175 of the sensor cover 70 and the second bottom 161 of the sensor housing 60, and between both sides of the protruding portion 176 of the second bottom facing portion 175 of the sensor cover 70 and the second bottom 161 of the sensor housing 60. As a result, the sealing agent 180 is formed into three layers: a first layer 180a, which is a layer between the portion radially outer than the protrusion 176 on the second bottom opposing portion 175 of the sensor cover 70 and the second bottom 161 of the sensor housing 60; a second layer 180b, which is a layer between the protrusion 176 on the second bottom opposing portion 175 and the second bottom 161 of the sensor housing 60; and a third layer 180c, which is a layer between the portion radially inner than the protrusion 176 on the second bottom opposing portion 175 and the second bottom 161 of the sensor housing 60.

[0103] 15 to 17 may be provided on the wall-facing surface 171 of the sensor cover 70. By providing the elastic body holding portion 172 on the wall-facing surface 171 of the sensor cover 70, the sealant 180 can be allowed to enter the elastic body holding portion 172, and therefore the sealant 180 that has entered the elastic body holding portion 172 can ensure waterproofing between the wall-facing surface 171 of the sensor cover 70 and the outer peripheral surface 68 of the wall 65 of the sensor housing 60.

[0104] As described above, by disposing the liquid sealant 180 between the second bottom 161 of the sensor housing 60 and the second bottom facing portion 175 of the sensor cover 70, the portion between the second bottom 161 and the second bottom facing portion 175 can be waterproofed by the sealant 180. As a result, the portions between the sensor housing 60 and the second bottom 161 and between the sensor cover 70 and the second bottom facing portion 175 can be waterproofed over a wide area by the sealant 180. As a result, the waterproofness of the accommodation portion 80 can be improved.

[0105] Furthermore, because second bottom facing portion 175 of sensor cover 70 has protrusion 176, the distance between second bottom 161 of sensor housing 60 and protrusion 176 can be made different from the distance between both sides of protrusion 176 in second bottom facing portion 175 and second bottom 161 of sensor housing 60. This allows sealant 180 to be arranged between second bottom 161 of sensor housing 60 and second bottom facing portion 175 of sensor cover 70 to be arranged in three layers: second layer 180b, which is a layer between second bottom 161 of sensor housing 60 and protrusion 176, and first layer 180a and third layer 180c, which are layers between second bottom 161 and both sides of protrusion 176 in second bottom facing portion 175, and second bottom 161, respectively. Therefore, the waterproofness between the second bottom 161 of the sensor housing 60 and the second bottom opposing portion 175 of the sensor cover 70 can be improved by the sealant 180 formed of three layers, thereby improving the waterproofness of the storage section 80.

[0106] In the above-described embodiment, the torque sensor device 10 is connected to the stub shaft 57 and the pinion gear 58a, but the shaft member 56 to which the torque sensor device 10 is connected may be something other than the stub shaft 57 or the pinion gear 58a. The torque sensor device 10 may be connected to, for example, the steering shaft 52 to detect the torque acting on the steering shaft 52.

[0107] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. The configurations described as the embodiments and modified examples may be combined as appropriate.

[0108] REFERENCE SIGNS LIST 10 Torque sensor device 11 Sensor case 15 Printed circuit board 16 Torque sensor 17 Steering angle sensor 20 Detection member 21 Input rotor 22 Cylindrical sleeve 23 Resin mold 25, 35 Blade-shaped member 31 Output rotor 32 Sleeve portion 40 Initial gear 41 Sensor gear 42 Magnet 50 Electric power steering device 51 Steering wheel 52 Steering shaft 53, 55 Universal joint 54 Lower shaft 56 Shaft member 57 Stub shaft 58 Steering gear 58a Pinion gear 58b Rack bar 59 Torsion bar 60 Sensor housing 61 Bottom portion 62 Through hole 63 Bearing holder 65 Wall portion 66 Inner peripheral surface 67 Recessed portion 68 Outer peripheral surface 68a, 77, 172 Elastic body holder 70 Sensor cover 71 Main body 72 Cylindrical portion 73 Rib 74 Mounting portion 75 Mounting bolt 76 Groove portion 78 Elastic body 80 Storage portion 82 Harness 83 Mounting member 85 Bearing 88 Seal member 90 Rack housing 91 Motor mounting portion 95 Tie rod 100 ECU 101 Vehicle speed sensor 102 Electric motor 102a Worm gear 102b Worm wheel 105 Ignition switch 106 Power supply device 161 Second bottom portion 171 Wall portion facing surface 175 Second bottom portion facing portion 176 Protrusion 180 Sealant

Claims

1. An electric power steering device comprising: a shaft member that transmits rotational torque; a detection member arranged on the shaft member; a sensor that detects movement of the detection member in a circumferential direction centered on the shaft member; a sensor housing having a bottom that intersects the axial direction of the shaft member and through which the shaft member passes, and a wall that is arranged around the surface of the bottom on which the detection member and the sensor are located; a sensor cover that is attached to the sensor housing from the side of the sensor housing where the wall is located, and forms a storage section together with the sensor housing; and a harness that is electrically connected to the sensor, wherein the detection member and the sensor are arranged inside the storage section, and the bottom of the sensor housing has a through hole through which the harness passes, and the harness passes through the through hole and is arranged from the inside to the outside of the storage section.

2. An electric power steering device according to claim 1, wherein the through hole is adjacent to an inner peripheral surface of the wall portion, and the inner peripheral surface of the wall portion has a recess along the through hole.

3. An electric power steering device as described in claim 1, wherein the sensor cover has a groove portion in a portion facing the wall portion of the sensor housing in the axial direction of the shaft member, the thickness direction of the wall portion being the groove width direction, and the sensor cover is attached to the sensor housing by fitting the wall portion into the groove portion.

4. An electric power steering device according to claim 3, wherein an elastic body is disposed in the groove portion and contacts the wall portion that enters the groove portion.

5. An electric power steering device according to claim 1, wherein the sensor housing holds a bearing at the bottom and rotatably supports the shaft member via the bearing, and the through hole is disposed between the bearing and the wall portion.

6. An electric power steering device as described in claim 1, wherein the sensor cover has a wall-facing surface that faces the outer peripheral surface of the wall of the sensor housing, and an elastic body that comes into contact with the sensor cover and the sensor housing is disposed between the wall-facing surface and the outer peripheral surface of the wall.

7. An electric power steering device as described in claim 1, wherein the sensor housing has a second bottom on the outside of the wall portion, the sensor cover has a second bottom opposing portion opposing the second bottom, and a liquid sealant is disposed between the second bottom and the second bottom opposing portion.

8. An electric power steering device as described in claim 7, wherein the second bottom opposing portion has a protruding portion that protrudes toward the second bottom portion, and the protruding portion protrudes toward the second bottom portion further than both sides of the protruding portion at the second bottom opposing portion in the radial direction of the bottom portion.

Images