Electric power steering device

Abstract

An electric power steering device (100) is provided with: an input shaft (13) to which a steering torque is input; an output shaft (15) connected to the input shaft (13) via a torsion bar (14); a torque sensor (40) that detects a steering torque; a connector (49) which is held by the housing (41) of the torque sensor (40) and is electrically connected to the torque sensor (40); a through-hole (61a) formed so as to penetrate the outer wall of the housing (5); and a cable (36) that is inserted into the through-hole (61a) and electrically connects an external device and the connector (49), the cable (36) having a relaxation section (36a) that extends linearly from the through-hole (61a) along the inner surface of the housing (5).

Description

Technical Field

[0001] The present invention relates to an electric power steering device. Background Art

[0002] In Japanese Patent Laid-Open Publication JP2017-61209A, an electric power steering device is disclosed, which has: an input shaft; an output shaft; a torque sensor; a housing; a cable that electrically connects the torque sensor and a controller that controls the drive of an electric motor; and a connector that is held by the housing of the torque sensor and is connected to the cable. Summary of the Invention

[0003] In the electric power steering device described in Japanese Patent Laid-Open Publication JP2017-61209A, the cable electrically connected to the controller is bent along the inner wall surface of the housing in the housing, and is also bent in a folded-back manner near the connector.

[0004] When the cable is bent in this way to be connected to the connector, a load is applied to the connector and the housing of the torque sensor that holds the connector due to the restoring force of the cable, which may cause adverse effects.

[0005] In view of the above problems, the present invention is made, and its object is to reduce the load acting on the connector and the housing of the torque sensor that holds the connector in an electric power steering device.

[0006] According to one aspect of the present invention, an electric power steering device includes: an input shaft to which a steering torque is input; an output shaft that is connected to the input shaft via a torsion bar; a torque sensor that is mounted across the input shaft and the output shaft and detects the steering torque; a housing that houses the input shaft, the output shaft, and the torque sensor; an electric motor that generates a steering assist torque according to the detection result of the torque sensor; a connector that is held by the housing of the torque sensor and is electrically connected to the torque sensor; a through hole that is formed to penetrate the outer wall of the housing; and a cable that is inserted into the through hole and electrically connects an external device and the connector, and the cable has a relaxation portion that extends linearly from the through hole along the inner surface of the housing. Brief Description of the Drawings

[0007] Figure 1 It is a structural diagram of an electric power steering device according to an embodiment of the present invention.

[0008] Figure 2 It is an external view of the vicinity of an assist mechanism in an electric power steering device according to an embodiment of the present invention.

[0009] Figure 3A cross-sectional view near the assist mechanism in the electric power steering device according to an embodiment of the present invention.

[0010] Figure 4 A top view near the assist mechanism in the electric power steering device according to an embodiment of the present invention, with the illustration of the first housing omitted.

[0011] Figure 5 A partial cross-sectional view showing an enlarged view of the torque sensor of the assist mechanism in the electric power steering device according to an embodiment of the present invention.

[0012] Figure 6 A diagram showing a comparative example of the assist mechanism in the electric power steering device according to an embodiment of the present invention. Detailed Embodiments

[0013] Hereinafter, with reference to the drawings, an electric power steering device 100 according to an embodiment of the present invention will be described.

[0014] The electric power steering device 100 is a device mounted on a vehicle and assists the operation of the steering wheel 1 performed by the driver.

[0015] In the present embodiment, as Figure 1 shown, a single pinion type electric power steering device 100 in which the operation torque applied by the driver and the operation assist torque generated by the electric motor 21 are input to the rack shaft 12 will be described.

[0016] First, with reference to Figure 1 , the overall structure of the electric power steering device 100 will be described.

[0017] The electric power steering device 100 includes: a steering mechanism 10 that steers the wheels 2 according to the rotation of the steering wheel 1 operated by the driver; an assist mechanism 20 that assists the operation of the driver; a steering sensor 40 that detects the operation steering input by the driver via the steering wheel 1; and a controller 30 that controls the drive of the electric motor 21 based on the detection result of the torque sensor 40.

[0018] The steering mechanism 10 has: a steering shaft 11 that rotates according to the rotation of the steering wheel 1; and a rack shaft 12 that steers the wheels 2 according to the rotation of the steering shaft 11.

[0019] The steering shaft 11 has: an input shaft 13 that rotates along with the operation of the steering wheel 1 by the driver; an output shaft 15 that is connected to the rack shaft 12 that steers the wheels 2; and a torsion bar 14 that connects the input shaft 13 and the output shaft 15.

[0020] A pinion 16 meshing with a rack 12a formed on a rack shaft 12 is formed at the lower part of an output shaft 15. When a steering wheel 1 is manipulated, a steering shaft 11 rotates, and this rotation is converted into a linear motion of the rack shaft 12 through the pinion 16 and the rack 12a, and the wheels 2 are steered via a knuckle arm 4. Alternatively, instead of the structure where the pinion 16 is formed at the lower part of the output shaft 15, a structure may be adopted in which a pinion shaft meshing with the rack shaft 12 and the output shaft 15 are connected via an intermediate shaft.

[0021] The power assist mechanism 20 includes: an electric motor 21 which is a power source for manipulating an assist torque; an output shaft 22 to which the driving force of the electric motor 21 is transmitted; and a reduction mechanism 3 which reduces the rotation of the electric motor 21 and transmits it to the output shaft 15. The reduction mechanism 3 includes: a worm shaft 3a connected to the output shaft 22 of the electric motor 21; and a worm wheel 3b meshing with the worm shaft 3a and fixed to the output shaft 15.

[0022] The output of the electric motor 21 is transmitted as an assist manipulation torque to the rack shaft 12 via the output shaft 15 after being reduced by the reduction mechanism 3.

[0023] A torque sensor 40 detects a manipulation torque applied to a torsion bar 14 based on the rotational angle difference between an input shaft 13 and an output shaft 15.

[0024] A substrate 47 (see Figure 5 ) of the torque sensor 40 and a controller 30 are electrically connected via a cable 36 serving as a signal line. Power is supplied from the controller 30 to the torque sensor 40 via the cable 36, and a manipulation torque signal detected by the torque sensor 40 is output to the controller 30.

[0025] Next, with reference to Figures 2 to 5 , the structure of the power assist mechanism 20 in the electric power steering apparatus 100 will be described in detail.

[0026] As shown in Figure 2 and Figure 3 , the power assist mechanism 20 includes an electric motor 21, a housing 5, an input shaft 13, a torsion bar 14, an output shaft 15, and a torque sensor 40. The input shaft 13, the output shaft 15, and the torque sensor 40 are housed in the housing 5.

[0027] As shown in Figure 2 and Figure 3 , the housing 5 has a first housing 50 and a second housing 60.

[0028] As shown in Figure 2 and Figure 3As shown, the first housing 50 has: a cylindrical portion 51; a flange portion 52 that extends radially outward from the outer periphery of the cylindrical portion 51 and covers the opening of the second housing 60; and a mounting portion 53 into which a bolt 18 for fastening the first housing 50 and the second housing 60 is inserted.

[0029] As Figure 3 shown, inside the cylindrical portion 51, a sealing member 91 that slidably contacts the outer peripheral surface of the input shaft 13 and a bearing 92 that rotatably supports the input shaft 13 are inserted. The sealing member 91 prevents foreign matter from entering the first housing 50.

[0030] As Figure 2 and Figure 3 as shown, etc., the mounting portion 53 is formed to project radially outward from the outer peripheral surface of the flange portion 52. In the present embodiment, the mounting portions 53 are provided at three locations at intervals in the circumferential direction.

[0031] As Figures 2 to 4 shown, the second housing 60 has: a first cylindrical portion 61; a second cylindrical portion 62 having an inner diameter smaller than that of the first cylindrical portion 61; a mounting portion 63 into which a bolt 18 for fastening the first housing 50 and the second housing 60 is inserted; a cable holder mounting portion 66 (see Figure 4 ), on which a cable holder 31 for holding the cable 36 is mounted; and a plate 69 that is provided inside the first cylindrical portion 61.

[0032] As Figure 2 shown, an electric motor 21 is mounted on the outer wall surface of the first cylindrical portion 61. As Figure 3 shown, a torque sensor 40 and a worm wheel 3b are housed inside the first cylindrical portion 61. A worm shaft 3a connected to the output shaft 22 of the electric motor 21 is configured to penetrate the first cylindrical portion 61 and mesh with the worm wheel 3b housed inside the first cylindrical portion 61. As Figure 3 shown, the inside of the first cylindrical portion 61 is divided by a disk-shaped plate 69 into a space for setting the torque sensor 40 and a space for setting the worm wheel 3b.

[0033] As Figure 4 shown, the first cylindrical portion 61 has a through hole 61a formed to penetrate the first cylindrical portion 61. The cable 36 is inserted through the through hole 61a.

[0034] As Figure 3 shown, inside the second cylindrical portion 62, a bearing 93 that rotatably supports the output shaft 15 and a sealing member 94 that slidably contacts the outer peripheral surface of the output shaft 15 are provided. The sealing member 94 prevents foreign matter from entering the second housing 60.

[0035] AsFigure 2 and Figure 3 As shown in Figure 3 , the first housing 50 and the second housing 60 are fastened by bolts 18. A ring-shaped O-ring 96 for sealing between them is provided between the first housing 50 and the second housing 60.

[0036] As Figure 3 shown, a hollow portion that opens on the lower end surface is formed at the axis center of the input shaft 13, and a torsion bar 14 is housed in the hollow portion. The upper side of the torsion bar 14 is connected to the input shaft 13 by a pin 17. The lower end portion of the torsion bar 14 protrudes from the lower end opening of the hollow portion of the input shaft 13 and is connected to the output shaft 15 via a serration 14a. The torsion bar 14 transmits the control torque input to the input shaft 13 via the steering wheel 1 to the output shaft 15 and twists and deforms at the axis center according to the control torque. Thus, the input shaft 13 and the output shaft 15 rotate relative to each other according to the amount of torsion of the torsion bar 14, and the torque sensor 40 detects the control torque based on the rotation angle difference between the input shaft 13 and the output shaft 15 generated by this relative rotation.

[0037] Next, with reference to Figures 3 to 5 the specific structure of the torque sensor 40 will be described. In addition, Figure 5 is Figure 3 an enlarged view of the region R enclosed by a circle in

[0038] As Figure 3 and Figure 5 shown, the torque sensor 40 has: a housing 41; a first sensor rotor 45 as a rotor part, which rotates integrally with the input shaft 13; a second sensor rotor 46, which rotates integrally with the output shaft 15; a substrate 47, which detects the control torque and outputs its signal to the controller 30; a connector 49, which is connected to a cable 36 (refer to Figure 3 and Figure 4 ).

[0039] As Figure 4 etc. shown, the housing 41 has a substantially ring shape, is inserted through by the input shaft 13, and is provided to be freely rotatable relative to the input shaft 13.

[0040] The housing 41 is formed of a resin material. As Figure 4 and Figure 5As shown, the housing 41 has: a cylindrical first cylindrical portion 41a; a cylindrical second cylindrical portion 41b, which has a larger diameter than the first cylindrical portion 41a; an annular protrusion 41c, which protrudes radially inward from the inner peripheral surface of the first cylindrical portion 41a; a raised portion 41d, which is formed so as to bulge radially outward from the outer peripheral surface of the first cylindrical portion 41a; and an engaging portion 48, which is formed so as to further protrude radially from the outer surface of the raised portion 41d. In the present embodiment, the protrusion 41c is formed so as to have a tapered tip toward the radially inner side.

[0041] As Figure 4 shown, the engaging portion 48 engages with a locking portion 68 formed on the plate 69. The locking portion 68 is provided in a pair so as to extend axially from the end face of the plate 69 and at intervals in the rotational direction of the input shaft 13. A leaf spring 80 is provided between one end face of the engaging portion 48 in the rotational direction and the locking portion 68. By the engaging portion 48 being pressed against one locking portion 68 by the elastic force of the leaf spring 80, relative rotation of the torque sensor 40 (housing 41) with respect to the outer housing 5 is restricted.

[0042] As Figure 5 shown, the first sensor rotor 45 has: a first rotor member 45a, which is press-fitted onto the outer peripheral surface of the input shaft 13; and a plurality of plate portions 45b, which are mounted on the lower end face of the first rotor member 45a so as to face the substrate 47 and are formed so as to extend radially. The first rotor member 45a is formed of a resin material. In addition, the plurality of plate portions 45b are arranged at predetermined intervals in the rotational direction. The first rotor member 45a and the plurality of plate portions 45b are integrated by insert molding to form the first sensor rotor 45.

[0043] As Figure 5 shown, an annular engaging groove 45c that engages with the protrusion 41c of the housing 41 is provided on the outer peripheral surface of the first rotor member 45a. The engaging groove 45c is formed in a shape in which its side surface is in surface contact with the side surface of the protrusion 41c. Specifically, the side surface of the engaging groove 45c is formed so that its width becomes narrower toward the bottom surface.

[0044] In the torque sensor 40 of the present embodiment, by the protrusion 41c engaging with the engaging groove 45c, the housing 41 is supported in a so-called floating state so as to be able to rotate relative to the input shaft 13 with the first rotor member 45a interposed therebetween. Thereby, as the input shaft 13 rotates, the plate portions 45b of the first sensor rotor 45 rotate relative to the substrate 47. In addition, by the protrusion 41c and the engaging groove 45c formed in the above-described shape engaging with each other, movement of the housing 41 in the axial and radial directions with respect to the input shaft 13 is restricted.

[0045] As Figure 5 shown, the second sensor rotor 46 has: a press-fitting portion 46a press-fitted to the outer peripheral surface of the output shaft 15; and a plurality of plate portions 46b formed to radially extend from the outer peripheral surface of the press-fitting portion 46a and mounted so as to face the substrate 47 with a predetermined interval in the rotational direction.

[0046] The substrate 47 is fixed within the housing 41 and disposed between the plate portion 45b of the first sensor rotor 45 and the plate portion 46b of the second sensor rotor 46. On the substrate 47, a detection coil pattern is formed by patterning. The detection coil pattern detects the rotational angle difference between the input shaft 13 and the output shaft 15, that is, the change in the magnetic field generated by the rotational angle difference between the first sensor rotor 45 and the second sensor rotor 46, thereby detecting the operating torque. Thus, the torque sensor 40 is an inductive sensor that detects the operating torque based on the change in inductance detected in the detection coil pattern.

[0047] As Figure 3 and Figure 4 shown, etc., the connector 49 is disposed on the upper surface of the housing 41 and held by the housing 41. The connector 49 is a female-shaped connector having a mounting port 49a. In the mounting port 49a, a male-shaped connector 37 provided at the tip of the cable 36 is inserted (see Figure 4 ).

[0048] One end of the cable 36 is connected to the connector 37 (torque sensor 40). The cable 36 is pulled out of the housing 5 through the through-hole 61a formed in the first cylindrical portion 61, the holder mounting portion 66, and the cable holder 31. The other end of the cable 36 is connected to the controller 30. In addition, it is not necessarily required to connect between the torque sensor 40 and the controller 30 with a single cable 36. For example, a relay connector may be provided on the cable holder 31 or the through-hole 61a, and the cable 36 inside the housing 5 and the cable 36 outside the housing 5 may be connected using the relay connector.

[0049] However, it can be considered that when guiding the cable 36 from the outside of the housing 5 to the inside, a through-hole extending radially toward the center of the housing 5 (the axis of the input shaft 13) is provided in the housing 5, and the cable 36 is inserted through the through-hole ( Figure 4 the area shown by P). However, in this structure, when the cable 36 is inserted through the through-hole, the cable 36 is guided into the housing 5 so as to face the input shaft 13 and the housing 41. Therefore, inside the housing 5, it is bent in order to bypass the input shaft 13 and the housing 41 (see Figure 4(dashed line). When the cable 36 is bent in this way to be connected to the connector 49, a load is applied to the connector 49 and the housing 41 of the torque sensor 40 that holds the connector 49 due to the restoring force of the cable 36, which may cause adverse effects. Specifically, when a load is applied to the connector 49, the housing 41 that holds the connector 49 may rotate while being pressed against the first rotor member 45a. In addition, when the first rotor member 45a rotates in a state where the housing 41 is pressed against the first rotor member 45a, the contact portion between the engaging groove 45c of the first rotor member 45a and the protrusion 41c of the housing 41 wears. As a result, looseness occurs in the substrate 47 held by the housing 41, and the detection accuracy of the torque sensor 40 may deteriorate.

[0050] Therefore, as Figure 4 shown, in the electric power steering apparatus 100 of the present embodiment, the through-hole 61a is provided at a position where the axis is parallelly offset from the position P toward the center of the housing 5 (the rotation axis of the input shaft 13). In other words, the through-hole 61a is provided in a plane orthogonal to the rotation axis of the input shaft 13 in such a manner that the axis is inclined with respect to the direction toward the center of the housing 5 (the rotation axis of the input shaft 13), that is, in such a manner that the opening of the through-hole 61a does not face the housing 41 of the torque sensor 40 and the input shaft 13.

[0051] By providing the through-hole 61a in this way, it is not necessary to bend the cable 36 inserted into the through-hole 61a in order to bypass the housing 41 of the torque sensor 40 and the input shaft 13. In other words, the cable 36 inserted into the through-hole 61a can be linearly guided along the inner surface of the housing 5 (hereinafter, the portion of the cable 36 that linearly extends along the inner surface of the housing 5 is referred to as the "relaxing portion 36a").

[0052] The portion of the cable 36 that connects the connector 49 and the relaxing portion 36a is bent (hereinafter, the portion of the cable 36 that connects the connector 49 and the relaxing portion 36a and has a bent shape is referred to as the "bent portion 36b"). In the bent portion 36b, the restoring force for the cable 36 to return to a straight state acts. On the other hand, in the relaxing portion 36a, no restoring force is generated. On the contrary, the relaxing portion 36a can absorb the load generated due to the restoring force of the cable 36 generated at other portions (such as the bent portion 36b) of the cable 36. Therefore, by providing the relaxing portion 36a on the cable 36, the load generated due to the restoring force of the cable 36 acting on the connector 49 and the housing 41 of the torque sensor 40 that holds the connector 49 can be reduced.

[0053] In addition, in the electric power steering apparatus 100 of the present embodiment, as Figure 4As shown, the connector 49 is disposed in a region sandwiching the input shaft 13 on the side opposite to the through hole 61a. Specifically, the connector 49 is disposed in a region sandwiching the surface F on the side opposite to the through hole 61a, where the surface F is a surface orthogonal to the relief portion 36a (axis D2 of the through hole 61a) among the surfaces including the rotation axis of the input shaft 13. Thus, by disposing the connector 49 in a region sandwiching the input shaft 13 on the side opposite to the through hole 61a, the length of the cable 36 in the housing 5 can be increased. Thereby, even if the cable 36 is bent, play can be provided in the cable 36 in an amount equivalent to a longer cable 36, and thus, the load generated by the restoring force of the cable 36 can be alleviated.

[0054] In addition, preferably, the angle θ formed between the connection direction D1 of the connector 49 and the cable 36 and the axis D2 of the through hole 61a is approximately 90°. For example, when the angle θ formed between the connection direction D1 of the connector 49 and the cable 36 and the axis D2 of the through hole 61a is set to 90 degrees or less (refer to Figure 6 , in Figure 6 , the angle θ is approximately 0°), when the elasticity of the cable 36 is lost due to aging deterioration or the like, the portion of the cable 36 between the connector 49 and the through hole 61a may deform linearly when attempting to connect them at the shortest distance (refer to the thicker dashed line in Figure 6 ). Thus, when the cable 36 deforms linearly, the cable 36 may contact the housing 41 of the torque sensor 40 and the input shaft 13, exerting an adverse effect. Conversely, when the angle θ is set to 90° or more, the length of the cable 36 becomes shorter, and thus, the play becomes smaller accordingly. Therefore, by setting the angle θ to approximately 90°, even if the cable 36 deforms linearly, the situation where the cable 36 contacts the housing 41 of the torque sensor 40 and the input shaft 13 can be suppressed, and the play of the cable 36 can be ensured to the maximum extent.

[0055] In addition, preferably, the connector 49 and the through hole 61a are located in the same plane orthogonal to the rotation axis of the input shaft 13. Thus, by disposing the connector 49 and the through hole 61a in the same plane, the bent portion of the cable 36 in the direction of the rotation axis of the input shaft 13 can be eliminated.

[0056] Alternatively, in the middle part between the connector 49 and the through-hole 61a, the cable 36 can be fixed to the housing 5 (the plate 69) by a fixing member (not shown). By fixing the cable 36 to the housing 5 (the plate 69) in this way, the load acting on the connector 49 and the housing 41 of the torque sensor 40 that holds the connector 49 can be reduced. In particular, it is preferable to fix the bent portion 36b to the housing 5 by a fixing member. By fixing the bent portion 36b, the restoring force of the bent portion 36b that tends to return to a straight state can be suppressed by the fixing member. Therefore, the load acting on the connector 49 and the housing 41 of the torque sensor 40 that holds the connector 49 can be further reduced.

[0057] Hereinafter, the structure, operation, and effects of the embodiments of the present invention will be summarized and described.

[0058] The electric power steering device 100 includes: an input shaft 13 to which a steering torque is input; an output shaft 15 that is connected to the input shaft 13 via a torsion bar 14; a torque sensor 40 that is mounted across the input shaft 13 and the output shaft 15 and detects the steering torque; a housing 5 that houses the input shaft 13, the output shaft 15, and the torque sensor 40; an electric motor 21 that generates a steering assist torque based on the detection result of the torque sensor 40; a connector 49 that is held by the housing 41 of the torque sensor 40 and is electrically connected to the torque sensor 40; a through-hole 61a that is formed so as to penetrate the outer wall of the housing 5; and a cable 36 that is inserted into the through-hole 61a and electrically connects an external device and the connector 49. The cable 36 has a relaxation portion 36a that extends linearly along the inner surface of the housing 5 from the through-hole 61a.

[0059] In this structure, the cable 36 has a relaxation portion 36a that extends linearly along the inner surface of the housing 5 from the through-hole 61a. Thereby, the amount of bending of the cable 36 can be reduced by an amount equivalent to that without bending the cable 36 to avoid the input shaft 13. As a result, the load generated by the restoring force of the cable acting on the connector 49 and the housing 41 of the torque sensor 40 that holds the connector 49 can be reduced.

[0060] In addition, in the electric power steering device 100, the connector 49 is provided in a region on the side opposite to the through-hole 61a with the input shaft 13 interposed therebetween, and the angle θ formed by the connection direction D1 of the connector 49 and the cable 36 and the axis D2 of the through-hole 61a is approximately 90°.

[0061] In this structure, the connector 49 is disposed in a region sandwiching the input shaft 13 and on the side opposite to the through-hole 61a. Therefore, the length of the cable 36 within the housing 5 can be increased. Thereby, even when the cable 36 is bent, play can be provided in the cable 36 by an amount equivalent to the cable 36 being longer. Thus, the load generated by the restoring force of the cable 36 can be alleviated. Further, the angle θ formed between the connection direction D1 of the connector 49 and the cable 36 and the axis D2 of the through-hole 61a is approximately 90°. Therefore, the amount of bending of the cable 36 can be minimized, and the length of the relief portion 36a can be maximally increased. For example, when the angle θ formed between the connection direction D1 of the connector 49 and the cable 36 and the axis D2 of the through-hole 61a is set to 90 degrees or more (refer to Figure 6 ), when the elasticity of the cable 36 is lost due to deterioration over time or the like, the portion of the cable 36 between the connector 49 and the through-hole 61a may linearly deform when attempting to connect them at the shortest distance (refer to Figure 6 's thicker dashed line). In this way, when the cable 36 linearly deforms, the cable 36 may contact the housing 41 of the torque sensor 40 and the input shaft 13, exerting an adverse effect. Therefore, by setting the angle θ to approximately 90°, even when the cable 36 linearly deforms, the situation where the cable 36 contacts the housing 41 of the torque sensor 40 and the input shaft 13 can be suppressed. Additionally, by maximally increasing the length of the relief portion 36a, the region for alleviating the load generated by the restoring force of the cable 36 can be increased.

[0062] Further, in the electric power steering device 100, the connector 49 and the through-hole 61a are located in the same plane orthogonal to the axis of rotation of the input shaft 13.

[0063] In this structure, by disposing the connector 49 and the through-hole 61a in the same plane, the bent portion of the cable 36 in the direction of the axis of rotation of the input shaft 13 can be eliminated.

[0064] The electric power steering device 100 further includes a fixing member for fixing the cable 36 to the housing 5. The cable 36 further has a bent portion 36b connecting the connector 49 and the relief portion 36a, and the fixing member fixes the bent portion 36b to the housing 5.

[0065] In this structure, since the bent portion 36b of the cable 36 is fixed to the housing 5, the load acting on the connector 49 and the housing 41 of the torque sensor 40 that holds the connector 49 can be reduced.

[0066] The embodiments of the present invention have been described above. However, the above embodiments merely represent a part of the application examples of the present invention, and do not mean to limit the technical scope of the present invention to the specific structures of the above embodiments.

[0067] The torque sensor 40 may also be configured to have the function of an angle sensor that detects the absolute rotation angle of the steering shaft 11.

[0068] In the above-described embodiment, the single-gear type electric power steering device 100 in which the operating torque applied by the driver and the operating assist torque generated by the electric motor 21 are input to the rack shaft 12 via the common steering shaft 11 has been described as an example. However, the electric power steering device 100 may also be a double-gear type electric power steering device in which the operating torque applied by the driver and the operating assist torque applied by the electric motor 21 are independently input to the rack shaft 12. In addition, the electric power steering device 100 is not limited to the rack and pinion type, and may also be a column assist type.

[0069] In the above-described embodiment, the case where the torque sensor 40 is an inductive sensor has been described. However, the torque sensor 40 may also be a magnetic sensor, and the torque detection method is not limited.

[0070] This application claims priority based on Japanese Patent Application No. 2022-194402 filed with the Japan Patent Office on December 5, 2022, and the entire contents of this application are incorporated herein by reference.

Claims

1. An electric power steering device, comprising: An input shaft to which a steering torque is input; An output shaft connected to the input shaft via a torsion bar; A torque sensor mounted across the input shaft and the output shaft to detect the steering torque; A housing that houses the input shaft, the output shaft, and the torque sensor; An electric motor that generates a steering assist torque based on the detection result of the torque sensor; A connector held by the housing of the torque sensor and electrically connected to the torque sensor; A through hole formed to penetrate the outer wall of the housing; A cable inserted into the through hole to electrically connect an external device and the connector, The cable having a relaxation portion linearly extending from the through hole along the inner surface of the housing.

2. The electric power steering device according to claim 1, wherein The connector is provided in a region on the opposite side of the input shaft from the through hole, The angle formed by the connection direction of the connector and the cable and the axis of the through hole is approximately 90°.

3. The electric power steering device according to claim 1, wherein The connector and the through hole are located in the same plane orthogonal to the axis of rotation of the input shaft.

4. The electric power steering device according to claim 1, wherein It further comprises a fixing member for fixing the cable to the housing, The cable further has a bent portion connecting the connector and the relaxation portion, The fixing member fixes the bent portion to the housing.

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