JP5040522B2 - Electric power steering device - Google Patents

Description

  The present invention relates to an electric power steering apparatus using an electric motor as a generation source of steering assist torque, and more particularly to an assembly structure of the electric motor and a control unit (ECU) for controlling driving of the electric motor.

  Many of recent vehicles are equipped with an electric power steering device (EPS) that assists the steering by the driver by transmitting the driving force of the electric motor to the steering shaft. In this electric power steering apparatus, a steering torque signal detected by a torque sensor is input to a control unit (ECU), and the control unit controls a drive current supplied to the electric motor based on the steering torque signal. The drive of the electric motor is controlled.

  In many cases, the electric motor and the control unit are separately mounted on the vehicle in a separated positional relationship, and a configuration in which the electric motor and the control unit are electrically connected to each other by a long harness is common. However, with such a connection configuration using a harness, it may be difficult to handle the harness depending on the layout in the engine room of the vehicle, power loss due to wiring resistance of the harness, radio noise increase, or the number of parts Various problems such as an increase were concerned.

  In order to solve such a problem, for example, Patent Document 1 proposes an electric power steering device in which an electric motor and a controller unit are arranged close to each other. Hereinafter, a conventional electric power steering apparatus in which an electric motor and a controller unit are disposed in close proximity will be described with reference to FIG.

  In FIG. 6, an electric power steering apparatus 100 includes an electric motor 102 that applies a steering assist force to a steering system including a steering shaft 101 and the like, and a control unit (ECU) 103 that controls driving of the electric motor. The electric motor 102 and the control unit 103 are attached to a gear box 105 attached to the base end side (upper right side in FIG. 6) of the steering column 104. The gear box 104 houses a speed reduction mechanism including a worm and a worm wheel, and the power of the electric motor 101 is transmitted to the steering system via the speed reduction mechanism.

  The electric motor 102 includes a flange portion 106 around the side on which the gear box 105 is attached. In the circumferential direction of the flange portion 106, a plurality of bolt holes are formed at equal pitch intervals, and the electric motor is fastened and fixed to the gear box by bolts 107 inserted through the bolt holes.

  Further, the flange portion 106 includes a flange overhang portion 108 formed by partially protruding in the circumferential direction, and a control unit 103 is provided on the surface of the flange overhang portion 108 on the output shaft side of the electric motor 102. The bus bar terminal 111 of the electric motor 102 is electrically connected to the terminal block 110 by being attached via bolts 109.

JP 2007-99011 A

  However, as shown in FIG. 6, when the electric motor 102 and the control unit 103 are arranged close to each other, the terminal portions (the terminal block 110 and the bus bar terminal 111) are exposed on the upper surface (flange mounting surface) of the control unit 103. Therefore, there is a possibility that water droplets generated by condensation or the like may adhere to the terminal portion and cause a failure or malfunction of the control unit 103 and the electric motor 102.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to protect a terminal portion that electrically connects an electric motor and a control unit that are arranged close to each other from water droplets or the like. An object is to provide an electric power steering apparatus.

An object of the present invention is an electric power steering device for assisting steering by a steering wheel, wherein the electric motor applies a steering assist force to a steering shaft connected to the steering wheel, and an output shaft of the electric motor. A speed reduction mechanism that transmits power of the electric motor to the steering shaft, a motor mounting surface to which a flange portion of the electric motor is attached, a gear box that houses the speed reduction mechanism, and a flange portion A control unit that is mounted on a surface of a motor output shaft side of a flange projecting portion formed by projecting a part in the circumferential direction, and is electrically connected to the electric motor to control a driving current of the electric motor; and a protective cover member for covering the connecting portion between the electric motor and the control unit, before The protective cover member includes a rectangular parallelepiped housing portion having an opening surface on the bottom surface and one side surface, an engagement portion formed by projecting an upper surface of the housing portion from the one side surface, and the engagement portion. A motor case insertion hole formed therein, and the housing portion is configured such that the motor case of the electric motor is inserted into the motor case insertion hole and the engagement portion abuts on the flange portion. This is achieved by fixing the control unit in a covered state .

  Further, the object is effective when the connecting portion includes a bus bar terminal extending in the circumferential direction from the flange portion and a terminal block disposed on the upper surface of the control unit and connected to the bus bar terminal. To be achieved.

  According to the electric power steering apparatus according to the present invention, since the terminal portion that electrically connects the electric motor and the control unit is covered with the cover member, the drip-proof effect against water droplets such as dew condensation is achieved. Have. This prevents water droplets from adhering to the terminal portion, which is a concern when the terminal portion is arranged on the upper surface of the control unit, and improves the reliability and operability of the electric power steering device. it can.

  Further, according to the electric power steering device of the present invention, the protective cover member has a rectangular parallelepiped housing portion whose bottom surface and one side surface are open surfaces, and the upper surface of the housing portion projects from one side surface. It consists of a formed engaging part and a motor case insertion hole drilled in the engaging part, and the entire control unit is covered by the housing part simply by inserting the motor case of the electric motor into the motor case insertion hole. It has a structure that can be done. As described above, since the cover member has a simple configuration and can be easily fixed, a drip-proof structure for protecting the terminal portion can be realized at low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a mechanism diagram showing a schematic configuration of an electric power steering apparatus according to an embodiment of the present invention. In the figure, the steering mechanism of the electric power steering apparatus 1 includes a steering shaft 3 that rotates in response to a steering operation of a steering wheel 2 attached to a tip portion, and a universal joint 4 on the other end side of the steering shaft 3. 5 and a rack and pinion mechanism 6 that converts the rotational motion of the steering shaft 3 into a linear motion of the rack shaft, and a tie rod 7 that transmits the motion of the rack shaft of the rack and pinion mechanism 6 to the steering wheel. It is composed of

  In addition, the column portion of the electric power steering apparatus 1 includes a torque sensor 8 that detects a steering torque input to the steering shaft 3 via the steering wheel 2 and a steering coupled to the steering shaft 3 via the speed reduction mechanism 9. An auxiliary electric motor 10 is provided.

  Driving of the electric motor 10 is controlled by a control unit (ECU) 11 equipped with a control circuit and the like. Electric power is supplied from the battery 12 to the control unit 11, and an ignition key signal is input from the ignition key 13. The control unit 11 calculates the steering assist command value I based on the steering torque value T detected by the torque sensor 8 and the vehicle speed V detected by the vehicle speed sensor 14, and the calculated steering assist command value is calculated. The drive current supplied to the electric motor 10 is controlled according to I.

  FIG. 2 is a perspective view showing a main part of the steering assisting part of the electric power steering apparatus according to the present embodiment as viewed from the steering wheel side.

  In the figure, a flange portion 15 of the electric motor 10 is connected to a motor mounting surface 17a of a gear box 17 provided at a base end portion of a steering column 16 that rotatably supports the steering shaft 3 via a plurality of bolts 18. It is attached. The gear box 17 houses a speed reduction mechanism 9 that transmits the power of the electric motor 10 to the steering shaft 3. The speed reduction mechanism 9 is a worm speed reducer including a worm coupled to the output shaft of the electric motor 10 and a worm wheel meshed with the worm and fitted to the steering shaft 3.

  The flange portion 15 of the electric motor 10 includes a flange protruding portion 15a formed by partially protruding in the circumferential direction, and the flange protruding portion 15a has a surface on the motor output shaft side (downward in FIG. 2). The control unit 11 is mounted via a plurality of bolts 19. The control unit 11 includes a terminal block 21 connected to three bus bar terminals 20 extending in the circumferential direction from a part of the flange portion 15 of the electric motor 10, and an electrical connection between the terminal block 21 and the bus bar terminal 20 is provided. The drive current of the electric motor 10 is controlled via the connection portion. Further, a connector 22 to which signal lines connected to various sensors such as the torque sensor 8 and the vehicle speed sensor 14 are attached is provided on the side surface of the control unit 11.

  In the electric power steering apparatus 1 according to the present embodiment, as shown in FIG. 2, in the state where the electric motor 10 and the control unit 11 are arranged close to each other, a connection portion between the electric motor 10 and the control unit 11, that is, a bus bar terminal. A protective cover member 23 that covers 20 and the terminal block 21 is attached. As shown in FIGS. 3 and 4, the protective cover member 23 includes a rectangular parallelepiped housing portion 24 having a bottom surface 24 a and a side surface 24 b as opening surfaces, and a top surface 24 c of the housing portion 24 on one side surface. (Open side surface) An engagement portion 25 is formed so as to protrude from the b, and a motor case insertion hole 26 formed in the engagement portion 25 is provided.

  The motor case insertion hole 26 of the protective cover member 23 is formed according to the outer diameter of the motor case 10 a of the electric motor 10. Then, as shown in FIG. 5, the motor case 10 a is inserted into the motor case insertion hole 26, and the engaging portion 25 comes into contact with the flange portion 15. Fixed in the coated state. As a result, the terminal block 21 exposed on the upper surface (flange mounting surface) 11 a of the control unit 11 and the bus bar terminal 20 connected to the terminal block 21 are completely covered by the casing 24 of the protective cover member 23. Is done. Here, the diameter of the motor case insertion hole 26 is set to be the same as the outer diameter of the motor case 10a so that the motor case insertion hole 26 can be fitted and fixed to the base (lower side in FIG. 4) of the motor case 10a. It is preferable.

  Further, a connector insertion hole 27 is formed in the facing surface 24d of the opening side surface 24b of the protective cover member 23, and even if the entire control unit 11 is covered by the protective cover member 23, a signal is sent to the connector 22 of the control unit 11. Wires can be connected.

  As described above, according to the electric power steering apparatus 1 according to the present embodiment, the bus bar terminal 20 of the electric motor 10 and the terminal block 21 of the control unit 11 connected to the bus bar terminal 20 include the housing of the protective cover member 23. The portion 24 is covered. Thus, even when the terminal block 21 is arranged on the upper surface 11a of the control unit 11 as in the present embodiment, it is possible to prevent water droplets from adhering to the terminal block 21, and thus the electric power steering apparatus 1 The reliability and operability can be improved.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to this, In the range which does not deviate from the meaning, it can change suitably.

It is a mechanism figure showing a schematic structure of an electric power steering device concerning an embodiment of the present invention. It is a principal part perspective view which shows the steering assistance part of the electric power steering device which concerns on this embodiment from the steering wheel side. It is a top view of the protective cover member concerning this embodiment. It is a side view of the protective cover member concerning this embodiment. It is a principal part perspective view which shows the state by which the protective cover member was mounted | worn with the control unit of FIG. It is a principal part perspective view which shows the conventional electric power steering apparatus which arrange | positioned the electric motor and the controller unit closely.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus 3 ... Steering shaft 9 ... Deceleration mechanism 10 ... Electric motor 10a ... Motor case 11 ... Control unit (ECU)
15 ... flange portion 15a ... flange overhanging portion 17 ... gear box 17a ... motor mounting surface 20 ... bus bar terminal 21 ... terminal block 23 ... protective cover member 24 ... Case 24a ... Bottom (opening bottom)
24b ... One side (opening side)
24c ... upper surface 25 ... engagement portion 26 ... motor case insertion hole

Claims (2)

An electric power steering device for assisting steering by a steering wheel,
An electric motor for applying a steering assist force to a steering shaft connected to the steering wheel;
A speed reduction mechanism connected to the output shaft of the electric motor and transmitting the power of the electric motor to the steering shaft;
A gear box having a motor mounting surface to which a flange portion of the electric motor is mounted, and housing the speed reduction mechanism;
A control mounted on the surface of the motor output shaft side of the flange extending portion formed by extending a part of the flange portion in the circumferential direction and electrically connected to the electric motor to control the drive current of the electric motor Unit,
A protective cover member covering a connection portion between the electric motor and the control unit ;
The protective cover member includes a rectangular parallelepiped housing portion having a bottom surface and one side surface as an opening surface, an engaging portion formed by projecting an upper surface of the housing portion from the one side surface, and the engaging portion. A motor case insertion hole drilled in, and
The casing is fixed in a state where the entire control unit is covered by the motor case of the electric motor being inserted into the motor case insertion hole and the engagement portion being in contact with the flange portion. An electric power steering device. 2. The electric power steering apparatus according to claim 1 , wherein the connection portion includes a bus bar terminal extending in a circumferential direction from the flange portion, and a terminal block disposed on an upper surface of the control unit and connected to the bus bar terminal.

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