JP2004203377A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a construction for mounting a motor used for an electric power steering device and a wiring construction for a wire harness, to reduce the space needed for pulling out the wire harness, by making the pull-out direction of the wire harness to be nearly identical to the output shaft direction of the motor, and performing the wiring with the pull-out of the wire harness being restricted, as well as to strengthen the construction for mounting the wire harness, thereby improving the layout characteristics of the device. <P>SOLUTION: The electric power steering device is designed to assist a steering shaft via a reduction gear within the gear box by the drive of the motor provided in a gear box. Pull-out portion is provided at a bracket of the motor, the wire harness is pulled out from the pull-out portion to the reduction gear side, and the pull-out direction of the wire harness is made to be nearly identical to the motor shaft as well. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a mounting structure for an assist motor used in an electric power steering device.

  Generally, an electric power steering device includes an electric motor to assist the steering force of a steering wheel, and controls the driving of the electric motor according to a torque detection signal detected by a torque sensor provided in a steering system. Has become.

  In this type of electric power steering apparatus, as shown in FIG. 7, an electric motor 51 is provided in a gear box of a steering column 52 or the like, and assists a steering shaft 53 via a speed reduction mechanism. Further, the steering column 52 is mounted between the vehicle body frame 54 and the dash panel 55 by mounting brackets 56, 56 due to space restrictions.

  This type of electric motor 51 is provided in a steering column 52 as shown in FIG. 8 in Patent Document 1, for example, and assists the steering of a steering shaft 53 via a reduction mechanism in a gear box 57. ing. A flange 58 is formed at an end of the steering column 52 so as to protrude outward from the gear box 57, and the electric motor 51 is attached to the gear box 57 via the flange 58. At this time, the electric motor 51 is provided on the gear box 57 in a state of traveling outside the steering column 52, and the wire harness 59 from the electric motor 51 is lateral from the motor case 60, that is, with respect to the motor shaft. It is arranged so as to be pulled out at right angles (rightward in FIG. 8).

  In addition, in Patent Document 2, for example, as shown in FIG. 9, the electric motor 71 has a motor shaft 73 rotatably supported by a pair of bearings 74 at both ends inside a cylindrical case 72. An armature 75 is disposed around the motor shaft 73, and a commutator 76 is attached to one end of the armature 75. A brush 78 is in contact with the surface of the commutator 76 by the elasticity of the spring 77. The brush holder 79 for holding the brush 78 is fastened to the bracket 90 by bolts 91.

  A grommet 80 is fitted to the motor case 72 of the electric motor 71 by fitting, and a wire harness 81 extends outward from the grommet 80. That is, also in this example, the wire harness 81 is pulled out from the electric motor 71 in a side direction, that is, in a direction perpendicular to the motor shaft 73 (downward in FIG. 9).

  As a result, in the above-described conventional electric motor, the wire harnesses 59 and 81 are drawn out to the side of the motor, and the drawing direction is perpendicular to the output shafts of the electric motors 51 and 71, that is, radially outward. It has such a structure.

JP 2001-180506 A JP 2000-166169 A

  However, in the electric motor mounting structure as described above, the electric motors 51 and 71 are mounted in a state where they travel outward from the steering column 52 in the radial direction, and the mounting state of the motors 51 and 71 is different from the mounting layout. There was a problem from a viewpoint.

  In particular, since the wire harnesses 59 and 81 are pulled out in a direction perpendicular to the output shafts of the electric motors 51 and 71, that is, radially outward from the motor cases 60 and 72, depending on the mounting position of the motor, In some cases, the wire harnesses 59 and 81 had to be extremely bent.

  Therefore, the layout of the motors 51 and 71 is greatly restricted, and a large current of several tens of amperes flows through the wire harnesses 59 and 81 used in the electric power steering device. , 81 is extremely bent, it may cause cracks in the harness coating or deteriorate the sealing performance, which may cause a serious failure.

  When the wire harnesses 59 and 81 are pulled out from the motors 51 and 71, the wire harnesses 59 and 81 are slackened from the drawer portions and arranged around the gear box. Therefore, when attaching the EPS to the vehicle body, an operator may accidentally touch the wire harnesses 59 and 81, or the wire harness may vibrate due to vibration during transportation, impact, or running vibration after mounting the EPS. In some cases, a large tension or impact is generated in the harnesses 59 and 81, and a large impact force is generated in the connector portions of the motors 51 and 71. For this reason, the connectors of the motors 51 and 71 may be damaged, and foreign matters such as water and dust may enter from the damaged portions and cause a failure.

  Therefore, an object of the present invention is to improve a mounting structure of a motor used in an electric power steering device and a wiring structure of a wire harness so that a drawing direction of the wire harness is substantially the same as an output shaft of the motor, It is an object of the present invention to reduce the space required for drawing out the wire harness, to strengthen the mounting structure of the wire harness, and to improve the layout of the device by performing wiring in a state where the drawing of the wire is restricted.

  In view of the above, an object of the present invention is to provide an electric power steering apparatus in which a motor is provided in a gear box, and the driving of the motor assists a steering shaft via a reduction gear in the gear box. This is achieved by providing a wire harness drawer, drawing out the wire harness from the drawer toward the reduction gear side, and making the wire harness withdraw in substantially the same direction as the motor shaft.

  In addition, the above object is effectively achieved by the connector being a connector protruding from the bracket on the side of the reduction gear and substantially in the same direction as the motor shaft.

  In addition, the object is to dispose a brush holder in a bracket, form the connector insertion hole in the bracket, and fit a connector protruding from the brush holder into the insertion hole. This is effectively achieved by drawing out the wire harness on the side of the reduction gear and substantially in the same direction as the motor shaft via the motor shaft.

  The above object is effectively achieved by forming the connector integrally with the brush holder with resin.

  In addition, the object is to form the bracket integrally with the gear box, provide the wire box with a lead-out portion for the wire harness, and set a pull-out direction of the wire harness on the reduction gear side and the motor shaft. This is achieved by having the same direction.

  Further, the above object is effectively achieved by the connector being provided on the reduction gear side from the gear box and protruding substantially in the same direction as the motor shaft.

  Further, the above object is achieved more effectively by disposing the drawer on the side opposite to the brush supported by the brush holder in the motor case.

  Further, the object is to provide a fixed portion for the wire harness drawn out from the drawer portion in the gear box, and the wire harness extending from the drawer portion positions the fixed portion on an extension of the wire harness in the drawing direction. This is achieved more effectively.

  Further, the above object is achieved by forming the fixing portion from a harness fixing bracket, the bracket being fixed at one end to a sensor cover of a sensor housing provided in the gear box, and a wire harness being fixed at the other end. This is achieved more effectively.

  As described above, according to the electric power steering device according to the present invention, in the electric power steering device including the assist motor in the gear box, the wire harness is pulled out from the motor bracket to the gear box side, and the drawing direction of the wire harness is changed. The direction was almost the same as the motor shaft. Thus, the direction in which the wire harness of the electric motor is drawn out, that is, the direction in which the brush holder is drawn out of the connector is on the gear box side and is substantially the same as the direction of the motor shaft. Therefore, there is no protrusion in the space around the electric motor and radially outside of the motor shaft, and the wire harness is pulled out to the gear box side and provided on the side opposite to the brush installation position. Therefore, the influence of noise due to brush discharge and the like is reduced, and interference with other devices due to drawing out of the wire harness is eliminated. As a result, the space can be effectively used, the layout of the device can be improved, and the wire harness can be easily pulled out of the connector.

  Further, the wire harness is fixed by a bracket at a position on an extension of the drawing direction from the drawer portion, and even if a large vibration or impact acts on the wire harness at the time of mounting the EPS or running, the wire harness is pulled out from the drawer portion. Excessive tension and stress are not generated in the wire harness extending to the bracket due to bending or deformation. Therefore, no damage occurs at the connector portion of the wire harness, and no foreign matter such as water or dust enters the motor, and the durability of the device is improved.

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

  FIG. 1 shows an external view of an electric power steering apparatus according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes a pinion shaft connected to a steering wheel (not shown). The rack column 1 'is provided with an electric motor 2 for assisting steering, and the electric motor 2 is provided on a motor shaft side, that is, a gear box 4 as a reduction mechanism arranged on the output shaft side (left side in FIG. 1). Fixed to.

  The gear box 4 accommodates a reduction gear provided on the pinion shaft 1, and the reduction gear meshes with a worm (not shown) mounted on a motor shaft of the electric motor 2, thereby causing the electric motor 2 to rotate. Is reduced to assist the pinion shaft 1.

  As shown in FIG. 2, a connector 5 having a substantially elliptical cross section is provided on the output shaft side end surface of the electric motor 2, and a connection pin 7 for connecting to a wire harness 6 is provided inside. And the connector on the wire harness 6 side. As shown in FIG. 2, the connector 5 extends from the outside of the end face on the motor output shaft side in substantially the same direction as the motor shaft 3 (the front side in FIG. 2). The wire harness 6 is drawn not to the motor 2 side but to the gear box 4 side as a reduction mechanism in order to facilitate attachment and detachment from the viewpoint of vehicle body space. As a result, the wire harness 6 connected to the connection piece 7 of the connector 5 is pulled out from the gear box 4 side of the electric motor 2 in substantially the same direction (substantially parallel) as the output shaft of the electric motor 2, that is, the motor shaft 3. It has such a structure.

  Reference numeral 8 denotes a bolt for attaching the electric motor 2 to the gear box 4.

  Therefore, since the wire harness 6 is pulled out in substantially the same direction as the motor shaft 3, the space outside in the direction perpendicular to the motor shaft 3 can be effectively used. That is, when the wire harness 6 is pulled out in the radial direction with respect to the motor shaft 3 as in the related art, the wire harness 6 may protrude and obstruct the layout of the device. On the other hand, the wire harness 6 drawn in the same direction as the motor shaft 3 can be arranged along the outer peripheral surface of the gear box 4, and the wire harness can be laid out with a small gap. Moreover, the electric motor 2 is usually installed in a narrow space due to the arrangement of the vehicle body. Therefore, in the above embodiment, since the wire harness 6 is drawn out from the electric motor 2 to the gear box 4 side, it is easy to wire the thick wire harness 6 and the gap formed by the gear box 4 is effectively utilized. Thus, the wire harness 6 can be easily attached and detached. In addition, the connector and the grommet eliminate unnecessary projections, resulting in a compact configuration. Therefore, the space around the device can be effectively used, and the layout of the device is improved.

  FIG. 3 is a sectional view showing a state in which a part of an electric motor used in an electric power steering device according to a second embodiment of the present invention is cut away. In the figure, a bracket 22 forming an output shaft side end surface is fastened to a substantially cylindrical motor case main body 21 of the electric motor 2 by bolts 23.

  A through hole 25 for a motor shaft 24 is formed in the center of the bracket 22, and the motor shaft 24 is rotatably supported by a bearing 26 in the through hole 25. A commutator 27 is arranged around the motor shaft 24, and a brush contacts the surface of the commutator 27.

  A brush holder 28 for holding the brush is arranged inside the bracket 22 and is attached to the bracket 22 by bolts 29. On the outer surface of the brush holder 28, a substantially cylindrical connector 30 is integrally formed of resin so as to protrude in the substantially same direction as the motor shaft 24. In the connector portion 30, a connecting pin 7 for connecting to the wire harness 31 is formed so as to protrude in substantially the same direction as the motor shaft 24. Here, the connecting pin 7 may be formed integrally with the connector 30 using resin. In the electric motor 2, an O-ring 33 is provided between the bracket 22 and the brush holder 28, whereby the electric motor 2 is completely sealed.

  Therefore, the connector 30 of the brush holder 28 and the connecting pin 7 formed in the connector 30 have a structure that extends in substantially the same direction with respect to the motor shaft 24, that is, in the substantially same direction. In addition to this, the molding die also has a simple structure as compared with the case of molding in the radial direction with respect to the motor shaft 24. As a result, the manufacturing cost is reduced and the reliability is improved.

  When the wire harness 31 is pulled out in the gear box 4 side and is pulled out in substantially the same direction as the motor shaft 24, when attaching and detaching the wire harness 31, sufficient space is provided radially outward with respect to the motor shaft 24. Even if the wire harness 31 is not provided, the wire harness 31 can be easily pulled out by using a gap having a shape such as the gear box 4. Therefore, the space around the electric motor 2 can be effectively used, and the layout is improved. Further, by integrally molding the motor bracket 22 and the gear box 4, the structure can be simplified and the space can be reduced.

  FIG. 4 shows a third embodiment of the present invention, in which a motor case 40 of the electric motor 2 is integrally formed with a yoke 41, a magnet holder 42 and a brush holder 43. The electric motor 2 includes a commutator 45 on the end face of the rotor 44 on the side opposite to the output shaft (left side in FIG. 4). The motor case 40 includes the output shaft side (right side in FIG. 4) and the opposite side on the output shaft side (left side in FIG. 4). And base portions 40A and 40B forming end surfaces of the base portion 40A, and a cylindrical portion 40C connected to the magnet holder 42 from an outer edge of the base portion 40A.

  A connector 46 for connecting the wire harness 6 is formed on the base portion 40A on the output shaft side of the motor case 40. A spring 47 and a brush 48 are housed in the brush holder 43, and the spring 47 urges the brush 48 axially against a commutator 45 on the end face of the rotor 44.

  Generally, a large noise is generated in the current flowing in the wire harness 6 due to the discharge from the brush 48. Therefore, in the third embodiment, the connector 46 is formed so as to protrude from the motor case 40 on the side opposite to the position where the brush 48 is installed, that is, from the motor case 40 toward the gear box. As a result, the influence of noise due to brush discharge on the wire harness 6 can be reduced.

  FIG. 5 shows a fourth embodiment of the present invention, in which the electric motor 2 is fixed to a gearbox 4 as a reduction mechanism arranged on the output shaft side (the left side in FIG. 5), and has an end face on the output shaft side. , A connector 5 is provided, and is connected to the connector on the wire harness 6 side. Further, the gear box 4 is provided with a sensor housing 101, the upper surface of which is covered with a sensor cover 102, which is fixed with four bolts 103 to seal the inside of the sensor housing 101.

  As shown in detail in FIG. 6, a bracket 104 having an L-shaped cross section extends upward on the sensor cover 102, and the bracket 104 is fastened together by a bolt 103 at a lower end thereof. Fixed to. On the other hand, a tie wrap 105 is attached to the upper end of the bracket 104, and forms a fixing portion 106 of the wire harness 6 located on an extension of the connector 5 in the drawing direction. As a result, the wire harness 6 is pulled out from the connector 5 and is arranged so as to be substantially in the same direction as the motor shaft. In addition, 107 is a tube 107 containing the wire harness 6.

  Therefore, since the wire harness 6 is fixed by the tie wrap 105, the rigidity of mounting the wire harness 6 on the gear box 4 side is increased, and when the electric power steering device is mounted on the vehicle body, an operator may erroneously grasp the wire harness. Even if vibration or impact occurs during transportation or running, no large tension or impact acts on the wire harness 6. As a result, stress concentration due to the high tension or impact of the wire harness 6 does not occur in the connector 5 and no failure occurs due to breakage, so that foreign matters such as water and dust do not enter the motor, and the durability of the device is improved. The performance is improved.

  In the above embodiment, a motor with a brush has been described as an example. However, the present invention is not limited to this. For example, even when the present invention is applied to a brushless motor, the same operation and effect as those of the above embodiment can be obtained.

1 is a schematic perspective view of an electric motor mounting structure showing a first embodiment of an electric power steering device according to the present invention. FIG. 2 is an end view of the motor case viewed from a direction of line AA in FIG. 1. FIG. 6 is a cross-sectional view illustrating a second embodiment of the present invention, in which a part of an electric motor is cut away. FIG. 9 is a sectional view showing a third embodiment of the present invention, in which a part of an electric motor is cut away. FIG. 10 is a schematic perspective view showing a fourth embodiment of the present invention and showing a drawing-out structure of a wire harness. (A) is a figure explaining a mode that a wire harness is fixed to a bracket, (b) is a diagram explaining a mode of a fixed part by a tie wrap. FIG. 1 is a schematic explanatory view showing a state in which an electric power steering device is mounted on a vehicle body. It is a schematic side view which shows the mounting structure of the conventional electric motor. It is a sectional view showing the internal structure of the conventional electric motor.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Pinion shaft 2 Electric motor 3 Motor shaft 4 Gear box 5 Connector 6 Wire harness 7 Connecting pin 21 Motor case main body 22 Bracket 24 Motor shaft 28 Brush holder 30 Connector 31 Wire harness 40 Motor case 43 Brush holder 44 Rotor 46 Connector 48 Brush 101 sensor housing 104 bracket 105 tie wrap 106 fixing part

Claims (10)

In an electric power steering apparatus, a motor is provided in a gear box, and the driving of the motor causes a steering shaft to be assisted via a reduction gear in the gear box.
A draw-out portion of a wire harness is provided on the bracket of the motor, and the wire harness is drawn out from the draw-out portion toward the reduction gear, and the pull-out direction of the wire harness is substantially the same as the motor shaft. Electric power steering device. 2. The electric power steering apparatus according to claim 1, wherein the lead-out portion is a connector protruding from the bracket on the side of the reduction gear and substantially in the same direction as the motor shaft. A brush holder is arranged in the bracket, the connector insertion hole is formed in the bracket, and a connector protruding from the brush holder is inserted into the insertion hole, so that the connector is inserted through the connector. 3. The electric power steering apparatus according to claim 1, wherein a wire harness is drawn out in the same direction as the motor shaft on the side of the reduction gear. The electric power steering device according to claim 2, wherein the connector is formed integrally with the brush holder using a resin. The electric power steering device according to claim 2, wherein a connection pin for the wire harness is provided in the connector, and the connection pin is formed integrally with the connector. The bracket was formed integrally with the gear box, and the gear box was provided with a lead-out portion for the wire harness, and the lead-out direction of the wire harness was on the reduction gear side, and was substantially in the same direction as the motor shaft. The electric power steering device according to claim 1. 7. The electric power steering apparatus according to claim 6, wherein the drawer is a connector protruding from the gear box on the side of the reduction gear and substantially in the same direction as the motor shaft. The electric power steering device according to claim 1, wherein the drawer is disposed in a motor case on a side opposite to a brush supported by the brush holder. The gear box is provided with a fixing portion for the wire harness drawn from the drawer portion, and the wire harness extending from the drawer portion is positioned on an extension of the drawing direction from the drawer portion. The electric power steering device according to claim 1. The fixing part comprises a harness fixing bracket, the bracket being fixed at one end to a sensor cover of a sensor housing provided on the gear box, and fixing the wire harness at the other end. 9. The electric power steering device according to claim 9.

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