Electric power steering device and electric drive device

Abstract

Provided is an electric drive device such as an electric power steering device capable of suppressing an increase in the number of components and an increase in cost. In an electric power steering device, a conductive resin clip is disposed in the middle of a wire harness, and the conductive resin clip holds the wire harness in a state in which the conductive resin clip is in contact with a shielding member of the wire harness and is directly fixed to a housing.

Description

Technical Field

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

[0002] Patent document 1 discloses a wiring harness 10, which includes: an electric wire 11, which has a core wire and an insulating sheath covering the core wire; a braided component 12, which covers at least the core wire and performs electromagnetic shielding; a path limiting component 13, which is formed in a long strip shape and has a higher bending stiffness than the electric wire 11; and an outer component 15, which covers the electric wire 11, the braided component 12 and the path limiting component 13.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: (Japanese) Patent Publication No. 2019-103221 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] When the wiring harness described in Patent Document 1 is used in an electric drive device such as an electric power steering system, the wiring harness acts as an electromagnetic antenna, easily introducing noise into the wiring harness and radiating its own noise. Therefore, in this application, it is considered possible to process the end of the braided component 12, which serves as a shielding member, and ground this end to the housing via a component separate from the harness's own retaining member to allow noise to escape.

[0008] Therefore, processing of the wire harness is required, which leads to a problem of an increase in the number of parts.

[0009] One object of the present invention is to provide an electric drive device such as an electric power steering device that can suppress an increase in the number of parts.

[0010] Technical solutions to technical problems

[0011] An electric power steering system according to an embodiment of the present invention includes a conductive resin clip disposed in a middle portion of a wire harness. The conductive resin clip holds the wire harness in contact with a shielding member of the wire harness and is directly fixed to a housing.

[0012] Therefore, according to one embodiment of the present invention, it is possible to suppress reduction in the number of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the electric power steering system according to the first embodiment as viewed from the front side of the vehicle.

[0014] Figure 2 This is a schematic diagram of the main parts of the electric power steering system according to the first embodiment as viewed from the rear side of the vehicle.

[0015] Figure 3 This is a schematic diagram of the wire harness according to the first embodiment.

[0016] Figure 4 This is a perspective view of the snap-on clip according to the first embodiment.

[0017] Figure 5 This is a schematic diagram of the main parts of the electric power steering system according to the second embodiment as viewed from the rear side of the vehicle.

[0018] Figure 6 This is a perspective view of a wire clip according to a second embodiment. DETAILED DESCRIPTION

[0019] [Implementation Method 1]

[0020] Figure 1 This is a schematic diagram of the electric power steering system according to the first embodiment as viewed from the front side of the vehicle.

[0021] An electric power steering system (electric drive system) 1 is a rack and pinion type steering device and includes an electric motor 3 for applying a steering force to a rack shaft 2 .

[0022] Rack shaft 2 extends in the left-right direction of the vehicle and is connected to tie rods 4 at both ends via joints 5. Rack shaft 2 is housed in an aluminum alloy rack housing 6. The ends of rack housing 6 are covered by a guard 7. The ends of rack shaft 2 protrude from guard 7. Movement of rack shaft 2 moves tie rods 4, which in turn steer steering wheels 8 via tie rods 4.

[0023] On one end side of the rack box 6 ( Figure 1 A steering gear box 9 is provided on the left side of the steering wheel 10. An input shaft 11 connected to a steering wheel 10 is rotatably supported in the steering gear box 9. The input shaft 11 is connected to a pinion shaft (not shown) via a torsion bar (not shown) so as to be relatively rotatable.

[0024] A torque steering angle sensor (sensor) 12 is provided on an upper portion of the steering gear box 9. The torque steering angle sensor 12 outputs a steering angle sensor output signal corresponding to the relative rotation amount between the input shaft 11 and the pinion shaft.

[0025] The pinion shaft meshes with the rack shaft 2 and transmits the steering torque input to the steering wheel 10 to the rack shaft 2 .

[0026] On the other end side of the rack box 6 ( Figure 1An actuator box 13 is provided on the right side of the rack shaft 2. The motor 3 is secured to the actuator box 13, which also houses an auxiliary mechanism that transmits the output of the motor 3 to the rack shaft 2. The auxiliary mechanism transmits the driving force of the motor 3 via the input pulley, belt, and output pulley to the nut, where it is converted into axial thrust on the rack shaft 2 by a ball screw mechanism. It should be noted that a chain can also be used instead of a belt.

[0027] The electric motor 3 forms a so-called EPS power unit, integrated with a motor ECU (control unit) 14. The motor ECU 14 receives not only steering angle detection signals from the torque steering angle sensor 12 but also information from other ECUs (e.g., the engine ECU) and sensors (e.g., wheel speed sensors) via CAN communication. The motor ECU 14 controls the driving of the electric motor 3 based on this information. In the following description, the electric motor 3 and the motor ECU 14 are collectively referred to as the EPP 15.

[0028] Figure 2 This is a schematic diagram of the main parts of the electric power steering system according to the first embodiment as viewed from the rear side of the vehicle.

[0029] The torque steering angle sensor 12 is provided with a sensor-side connector 16. A first wire harness 17 and a second wire harness 18 are connected to the sensor-side connector 16. The length of the first wire harness 17 is set shorter than that of the second wire harness 18.

[0030] A motor-side first connector 20 that can be connected to the first terminal 19 of the EPP 15 is provided at an end portion of the first harness 17 on the opposite side from the sensor-side connector 16 .

[0031] A second motor-side connector 22, connectable to the second terminal 21 of the EPP 15, is provided at the end of the second wiring harness 18 opposite the sensor-side connector 16. The first terminal 19 is located closer to the steering gearbox 9 (pinion shaft) than the second terminal 21. The first and second wiring harnesses 17 and 18 provide the motor ECU 14 with detection signals (control signals) for driving and controlling the electric motor 3.

[0032] An adjusting screw 6a is attached to the rack housing 6. The adjusting screw 6a adjusts a set load of a coil spring that urges the rack shaft 2 toward the pinion shaft via a rack holder (not shown).

[0033] Furthermore, a snap-on clip (conductive clip) K1 made of conductive resin is mounted on the rack housing 6 for fixing the first and second harnesses 17 and 18 to the rack housing 6. The snap-on clip K1 is mounted on the shielding member 24 (see FIG. Figure 3 ) is held, and the snap-on fixing portion K1a is inserted into and fixed to the snap-on wire clamp fixing hole 6b of the rack case 6 (refer to Figure 4 ).

[0034] Figure 3 This is a schematic diagram of the wire harness according to the first embodiment.

[0035] The first wiring harness 17 includes: an electric wire 23, which has a core wire that transmits the detection signal of the torque steering angle sensor 12 to the motor ECU 14 and an insulating sheath covering the core wire; a shielding component 24, which is a conductive metal that covers and accommodates the electric wire 23 inside, and is formed into a tubular shape by weaving thin bare wires to shield the introduction of external noise into the first wiring harness 17 or the noise radiated by the core wire of the first wiring harness 17; a path limiting component 25, which fixes the electric wire 23; a fixing component 26, which fixes the shielding component 24 and the path limiting component 25; and an exterior component 27, which covers the electric wire 23, the shielding component 24 and the path limiting component 25.

[0036] It should be noted that the second wire harness 18 also has the same structure.

[0037] Figure 4 This is a perspective view of the snap-on clip according to the first embodiment.

[0038] The snap-on clip K1 made of conductive resin includes a snap-on fixing portion K1a inserted and fixed to the Figure 2 The rack housing 6 shown includes a snap-on clip fixing hole 6 b and a belt portion K1 b for holding the shielding member 24 of the first and second wire harnesses 17 and 18 .

[0039] That is, the snap-on clip K1 formed of a conductive resin holds the first and second wire harnesses 17 and 18 in a state of contact with the shielding members 24 of the first and second wire harnesses 17 and 18 , and is directly fixed to the rack housing 6 .

[0040] Next, the effects of the first embodiment will be described.

[0041] (1) The shield members 24 of the first and second wire harnesses 17 and 18 are held by the snap-fit ​​clamps K1 formed of a conductive resin, and the snap-fit ​​fixing portions K1 a are inserted and fixed to the snap-fit ​​clamp fixing holes 6 b of the rack housing 6 .

[0042] Therefore, the shield member 24 that shields external noise from being introduced into the first and second wire harnesses 17 and 18 or noise radiated from the core wires of the first and second wire harnesses 17 and 18 can be directly connected to the rack housing 6 .

[0043] Furthermore, since the radiated noise can be grounded to the rack housing 6 to release the noise, no additional components are required.

[0044] Furthermore, it is unnecessary to process the end portion of the shielding member 24, and the number of other components can be reduced.

[0045] (2) The shield member 24 is made of conductive metal and is formed into a tubular shape by braiding thin bare wires. A core wire for transmitting the detection signal of the torque steering angle sensor 12 to the motor ECU 14 is housed in the tube.

[0046] Therefore, the core wires of the first and second harnesses 17 and 18 can be electrically protected from noise introduction from the outside, and the core wires of the first and second harnesses 17 and 18 can be protected from radiated noise outside the rack housing 6 .

[0047] (3) The snap-on clamp K1 formed of a conductive resin includes: a snap-on fixing portion K1 a inserted and fixed to the snap-on clamp fixing hole 6 b of the rack housing 6 ; and a belt portion K1 b that holds the shielding member 24 of the first and second wire harnesses 17 and 18 .

[0048] Therefore, the snap-on clip K1 formed of a conductive resin can be physically fixed and connected to the rack housing 6 , and can also be electrically connected, and no additional components such as screws are required for connection to the rack housing 6 .

[0049] (4) The rack housing 6 is formed of aluminum alloy.

[0050] Therefore, the rack housing 6 itself can release noise.

[0051] [Implementation Method 2]

[0052] Figure 5 This is a schematic diagram of the main parts of the electric power steering system according to the second embodiment as viewed from the rear side of the vehicle. Figure 6 This is a perspective view of a wire clip according to a second embodiment.

[0053] The basic configuration of the second embodiment is the same as that of the first embodiment, and therefore only the differences from the first embodiment will be described.

[0054] In the first embodiment, the shielding member 24 of the first and second wire harnesses 17 and 18 is held by a snap-on clamp K1 formed of a conductive resin, and the snap-on fixing portion K1a is inserted and fixed into the snap-on clamp fixing hole 6b of the rack housing 6. However, in the second embodiment, the shielding member 24 of the first and second wire harnesses 17 and 18 is fastened to the outer periphery of the rack housing 6 and held together by the belt portion (fixing portion) K2a of the tie-type clamp K2 formed of a conductive resin.

[0055] Next, the effects of the second embodiment will be described.

[0056] In addition to the effects (1), (2), and (4) of the first embodiment, the following effects are also achieved.

[0057] (1) The rack housing 6 does not need to be machined for the snap-on wire clamp fixing hole 6 b, which can further reduce costs. Since the rack housing 6 is directly fastened, the close fit is good and the resistance value is stable, so noise can escape more easily.

[0058] [Other Implementation Methods]

[0059] While the embodiments for carrying out the present invention have been described above, specific aspects of the present invention are not limited to those of the embodiments, and design changes that do not depart from the spirit of the invention are also encompassed by the present invention.

[0060] For example, in the embodiment, an electric power steering device is described as an example of an electric drive device, but the present invention is not limited to this. The conductive resin wire clamp of this embodiment can be applied to electric drive devices such as an electric brake device having a wiring harness held in a housing and covered by a shielding component for providing a control signal to a control unit, an electric transmission system for a motor vehicle, and the like.

[0061] This application claims the benefit of priority based on Japanese Patent Application No. 2023-040597, filed on March 15, 2023. The entire disclosure of Japanese Patent Application No. 2023-040597, filed on March 15, 2023, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety.

[0062] Description of Reference Numerals

[0063] 1: Electric power steering device (electric drive device);

[0064] 6: rack box (housing);

[0065] 12: Torque rudder angle sensor (sensor);

[0066] 14: Motor ECU (control unit);

[0067] 17: First harness (harness);

[0068] 18: Second wiring harness (wiring harness);

[0069] 24: shielding components;

[0070] K1: snap-on wire clamp (conductive resin wire clamp);

[0071] K1a: snap-on fixing part (fixing part);

[0072] K2: Cable tie type clamp (conductive resin clamp);

[0073] K2a: belt part (fixing part).

Claims

1. An electric power steering device, characterized in that: The electric power steering device has a wiring harness, The wiring harness is provided in the housing and electrically connects the control unit for controlling the motor and the sensor for detecting the steering state, and is covered by a shielding member. A conductive resin clip is arranged in the middle of the wiring harness. The conductive resin clip holds the wire harness in a state of being in contact with a shielding member of the wire harness and is directly fixed to the housing.

2. The electric power steering device according to claim 1, wherein: The shielding member is a conductive metal, woven from thin bare wires to form a tube. A core wire for transmitting a detection signal from the sensor to the control unit is housed in the tube.

3. The electric power steering device according to claim 1, wherein: The conductive resin clip includes a fixing portion that can be fixed to the housing.

4. The electric power steering device according to claim 3, characterized in that The fixing portion of the conductive resin clip has a snap-fit ​​shape.

5. The electric power steering device according to claim 3, wherein: The conductive resin clip is in the shape of a cable tie so that the fixing portion can be fastened to the housing.

6. The electric power steering device according to claim 3, wherein: The housing is formed of aluminum alloy.

7. An electric drive device, characterized in that: The electric drive device includes a wiring harness held in a housing and covered by a shielding member for supplying a control signal to a control unit. A conductive resin clip is arranged in the middle of the wiring harness. The conductive resin clip holds the wire harness in a state of being in contact with a shielding member of the wire harness and is directly fixed to the housing.

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