JP2010254168A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device capable of coping with a layout of every mounted vehicle with one kind of electric motor by changing a phase when an electric motor is mounted to a gear box. <P>SOLUTION: In this electric motor, an external housing is constituted by a bottomed cylindrical motor case whose one end face is opened, and a flange member mounted to the motor case to block the opening. This electric motor is fastened and fixed to the gear box while an inside low part of an outside surface of a flange member is fitted with an inside low part of a motor mounting face formed to the gear box. A plurality of fastening bolt holes are bored on the flange member and the motor mounting face concentrically with a rotary shaft of the electric motor as a center, and a shape of the bolt hole is a circular arc long hole having an arc formed along a concentric circle with the rotary shaft of the electric motor as a center. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric power steering apparatus including an electric motor that applies a steering assist torque to a steering mechanism, and more particularly to an improvement in an electric motor mounting structure in the electric power steering apparatus.

  Many of the vehicles in recent years 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 through a reduction mechanism or the like. 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 the drive current supplied to the electric motor based on the steering torque signal. The driving of the motor is controlled, and an appropriate steering assist force is applied to the steering mechanism.

  In general, an electric motor and a control unit in this type of electric power steering apparatus have a driving current such as a power harness or a bus bar terminal for each phase of a motor stator (for example, three phases including a U phase, a V phase, and a W phase). It is electrically connected via a supply member (see, for example, Patent Document 1).

JP 2007-106234 A

  However, in a vehicle equipped with such an electric power steering device, the installation conditions differ depending on the vehicle type. Therefore, the extraction phase of the above-described power harness, busbar terminal, etc. may have to be changed. Standardization could not be achieved. Therefore, in the conventional electric power steering apparatus, since several types of electric motors corresponding to the type of vehicle to be mounted have to be manufactured, there is a problem in that the manufacturing cost increases.

  In addition, in the case of an integrated type (proximity arrangement type) in which the electric motor and the control unit are electrically connected via the bus bar terminal, the mounting phase of the electric motor and the control unit is changed for each vehicle model due to layout restrictions. In some cases, this has been a factor that hinders the standardization of electric motors.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to change the phase when the electric motor is attached to the gear box, so that one type of electric motor can be used for each mounted vehicle. An object of the present invention is to provide an electric power steering apparatus adapted to the layout.

  An object of the present invention is to provide an electric power steering apparatus including an electric motor that applies a steering assist force to a steering mechanism via a transmission mechanism housed in a gear box, and a control unit that controls driving of the electric motor. The outer casing of the electric motor is constituted by a bottomed cylindrical motor case having an open end, and a flange member attached to the motor case so as to close the opening. The electric motor is fixed to the gear box via a fastening bolt in a state in which the spigot formed on the outer surface of the flange member is fitted to the spigot formed on the motor mounting surface of the gear box, and the fastening The plurality of bolt holes through which the bolts are inserted are the same around the rotation axis of the electric motor in the flange member. The bolt holes are formed at equal intervals on the top, and the shape of the bolt holes is an arc-shaped long hole having an arc formed along a concentric circle with the rotation axis of the electric motor as a center. Achieved.

  Moreover, the said objective is achieved effectively by the said bolt hole being distribute | arranged at equal intervals along the same circle centering on the rotating shaft of the said electric motor at equal intervals.

  Further, the object is that the electric motor and the control unit are electrically connected via a bus bar terminal pulled out from a part of the flange member, and the control unit is along a direction in which the bus bar terminal is pulled out. This is achieved effectively by being fastened and fixed to the overhanging portion of the flange member formed as described above.

  Further, the above object is that the connection fixing long hole formed in the bus bar terminal and the fastening fixing long hole formed in the projecting portion of the flange member are centered on the rotating shaft of the electric motor. Are arranged on the concentric circles, and each shape is effectively formed by a shape having an arc formed along the concentric circles.

  According to the electric power steering apparatus of the present invention, the bolt holes through which the bolts are inserted when the electric motor is fastened and fixed to the mounting surface of the gear box are arranged at equal intervals on the same circle centering on the rotating shaft of the electric motor. The bolt hole has a circular arc-shaped hole having an arc formed along a concentric circle with the rotation axis of the electric motor as a center. Thereby, it becomes possible to change easily the phase at the time of attaching an electric motor to a gear box, and the pull-out directions of a power harness, a bus-bar terminal, etc. can be changed suitably to a desired direction. As a result, the electric motor can be standardized to one type, and the manufacturing cost can be reduced.

It is a mechanism figure showing a schematic structure of an electric power steering device concerning an embodiment of the present invention. It is principal part sectional drawing which shows the steering assistance part of the electric power steering apparatus which concerns on 1st Embodiment of this invention. (A) is a schematic side view which shows the electric motor which concerns on 1st Embodiment of this invention, (b) is the schematic bottom view. It is a principal part external view which shows the steering assistance part of the electric power steering apparatus which concerns on 2nd Embodiment of this invention. (A) is a schematic side view which shows the electric motor which concerns on 2nd Embodiment of this invention, (b) is the schematic bottom view.

  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.

  The driving of the electric motor 10 is controlled by a control unit (ECU) 11 equipped with a drive circuit, a control circuit, and the like. The control unit 11 is supplied with electric power from a battery (power source) 12 and receives an ignition key signal from an 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.

  The above-described electric power steering apparatus 1 is a column assist type in which the electric motor 10 and the speed reduction mechanism 9 are arranged in the column portion, but the present invention is not limited to this, and for example, the electric motor 10 and the speed reduction mechanism 9. However, a pinion assist type provided in the pinion part of the rack and pinion mechanism or a rack assist type provided in the rack part may be used.

  FIG. 2 is a cross-sectional view of the main part showing the steering assisting part of the electric power steering apparatus according to the first embodiment of the present invention.

  In the figure, the external housing of the electric motor 10 is composed of a bottomed cylindrical motor case 15 having an opening at one end and a flange member 16 attached so as to close the opening of the motor case 15. The motor case 15 and the flange member 16 are configured to be coupled by screw fastening at three locations. Bearings 17 and 18 are press-fitted and fixed in the bottom central recess 15a of the motor case 15 and the inner central recess 16a of the flange member 16, respectively, and the motor shaft 19 is rotatably supported via the bearings 17 and 18.

  A motor rotor 20 is provided around the motor shaft 19 in the motor case 15 so as to rotate integrally with the motor shaft 19. On the other hand, a motor stator 21 is disposed on the inner peripheral surface of the motor case 15 facing the motor rotor 20. Is provided so as to surround the outer peripheral surface of the rotor motor 20. A resolver 22 for detecting the rotation angle (rotation position) of the motor rotor 20 is disposed on one end side (left side in FIG. 2) of the motor shaft 19 located outside the flange member 16.

  The electric motor 10 having such a configuration is such that the outer surface of the flange member 16 is in contact with the motor mounting surface 25a of the gear box 25 in which the worm 23 and the worm wheel 24 constituting the speed reduction mechanism 9 are accommodated. The bolt 26 inserted through the bolt hole 16b of the flange member 16 is fixed by being fastened to a screw hole 25b formed in the motor mounting surface 25a. At this time, the spigot protrusion 16c provided around the outer surface of the flange member 16 is formed into a spigot recess (hollow opening) 25c formed on the motor mounting surface 25a in a shape corresponding to the spigot protrusion 16c. It is mated.

  The speed reduction mechanism 9 housed in the gear box 25 is connected to the motor shaft 19 of the electric motor 10 at one end (right side in FIG. 2) and is rotatable through bearings 27 and 28 disposed at both ends. Is a worm reducer comprising: a worm 29 supported by the worm 29; and a worm wheel 30 meshing with the worm 29 and having the inner peripheral surface fitted with the steering shaft 3. The motor shaft 19 and the worm 29 are engaged with a spline shaft portion 19a formed at the distal end portion of the motor shaft 19 in a spline hole 29a formed at the proximal end portion (right side in FIG. 2) of the worm 29, Transmission of rotational force by the electric motor 10 is freely coupled. Here, the coupling between the motor shaft 19 and the worm 29 is a spline coupling, but the present invention is not limited to this, and may be a coupling by an elastic coupling, for example.

  2 is a power harness 31 for supplying current that electrically connects each phase of the stator 21 and the control unit 11, and the member indicated by reference numeral 32 is the resolver 22. And a sensor harness 32 that electrically connects the control unit 11 to each other.

  FIG. 3A is a schematic side view showing the electric motor according to the first embodiment of the present invention, and FIG. 3B is a schematic bottom view thereof. As shown in the figure, the three bolt holes 16b through which the motor fastening and fixing bolts 26 are inserted are arranged at equal intervals on a concentric circle C1 centered on the axis (point O) of the motor shaft 19 of the electric motor 10. The bolt holes 16b are arranged in a circular arc shape having an arc formed along a concentric circle C1 with the point O as the center. Although not shown here, screw holes 25b formed in the motor mounting surface 25a of the gear box 25 are arranged at positions corresponding to the three bolt holes 16b. Accordingly, in this electric motor 10, the phase of attachment to the gear box 25 can be appropriately changed within the range of the arc-shaped bolt hole 16b, and the pull-out direction of the power harness 31 can be arbitrarily changed to a desired direction. It is like that.

  Further, a screw hole is formed in the surface where the motor case 15 comes into contact with the flange member 16 at equal intervals in three directions along the circumferential direction, and the motor case 15 is connected to the motor case 15 via a screw 33 inserted through the screw hole. The flange member 16 is coupled to the flange member 16. In the two-point mounting structure that has been generally used conventionally, the housing is twisted due to the magnetic force, and thus there are concerns about problems such as operating noise and torque fluctuations. However, the electric motor 10 according to the present embodiment is concerned. Then, by providing the fixing portions in three directions, the rigidity is improved and the deformation of the motor case 15 is prevented. As a result, torque fluctuations and operating noise can be suppressed.

  As described above, according to the electric power steering apparatus according to the present embodiment, the bolt hole 16b through which the bolt 26 is inserted when the electric motor 10 is fastened and fixed to the motor mounting surface 25a of the gear box 25 is provided in the electric motor 10. Are provided at equal intervals along the same circle C1 centered on the axis O of the motor shaft 19 and the shape of the bolt holes 16b is an arc-shaped length having an arc formed along the concentric circle C1. It is a hole. Thereby, the phase at the time of attaching the electric motor 10 to the gear box 25 can be easily changed, and the drawing direction of the power harness 31 and the like can be appropriately changed to a desired direction.

  In addition, since the electric motor 10 is fastened and fixed to the motor mounting surface 25a of the gear box 25 at three or more positions along the concentric circle C1, the gap between the flange member 16 of the electric motor 10 and the gear box 25 is set. As a result, the operating noise of the electric power steering apparatus 1 can be reduced.

  FIG. 4 is a main part external view showing a steering assisting part of the electric power steering apparatus according to the second embodiment of the present invention. FIG. 5A is a schematic side view showing an electric motor according to the second embodiment of the present invention, and FIG. 5B is a schematic bottom view thereof. In the figure, the same members as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 4, the electric power steering apparatus according to the present embodiment has a structure in which an electric motor 10 </ b> A and a control unit (ECU) 11 </ b> A are arranged close to each other. As shown in FIG. 5B, three bus bar terminals 35 are pulled out from a part of the flange member 16A of the electric motor 10A as a drive current supply member in the outer diameter direction. Each bus bar terminal 35 is fixed by fastening a mounting screw (not shown) inserted through a long hole 35a at the tip of the bus bar terminal 35 to a terminal block disposed at the bottom of the control unit. 10A and the control unit 11A are electrically connected. Overhang portions 16Ad of the flange member 16A are formed on both sides of the three bus bar terminals 35 along the pull-out direction, and bolts 36 (see FIG. 4) for fastening and fixing the control unit 11A to each of the overhang portions 16Ad. ) Is inserted through a long hole 16Ae.

  The long hole 35a drilled in the bus bar terminal 35 and the long hole 16e drilled in the overhanging portion 16Ad of the flange member 16A are on a concentric circle C2 centering on the axis O of the motor shaft 19 of the electric motor 10A. Each of the shapes is formed in a shape having an arc formed along a concentric circle C2.

  Further, as in the first embodiment described above, the flange member 16A has three bolt holes through which the motor fastening fixing bolts 26 are inserted so that the phase when the electric motor 10A is attached to the gear box 25 can be appropriately changed. 16Ab is drilled at equal intervals on a concentric circle C1 centered on the axis O of the motor shaft 19 of the electric motor 10A.

  As described above, according to the electric power steering apparatus according to the present embodiment, even when the control unit 11A is attached to a part of the flange member 16A of the electric motor 10A, the bolt hole is the same as in the first embodiment described above. The phase in which the electric motor 10A is attached to the gear box 25 can be changed within the range of 16 Ab. Thereby, the pull-out direction of the bus bar terminal 35 can be appropriately changed according to the installation space of the vehicle on which the electric power steering device 1 is mounted.

  Further, in the present embodiment, the long hole 35a formed in the bus bar terminal 35 and the long hole 16e formed in the overhanging portion 16Ac of the flange member 16A are arranged on the concentric circle C2 and have respective shapes. Is formed in a shape having an arc formed along the concentric circle C2. Accordingly, the phase when the control unit 11A is attached to the electric motor 10A can be changed within the range of the long holes 16Ad and 35a, and the control unit 11A can be handled so as not to interfere with other parts. Therefore, problems in the installation layout when mounted on the vehicle can be reduced.

  Furthermore, as in the present embodiment, the mounting of the electric motor 10A and the control unit 11A is made concentric, so that the concentricity with the worm 29 of the speed reduction mechanism 9 is secured, and noise caused by friction due to bias is generated. Since the control unit 11A can be suppressed and is disposed at a stable position from the center O of the electric motor in the outward direction, the stress of the flange member 16A due to vehicle vibration and moment can be stabilized. Defects such as cracks and dropouts of parts can be eliminated.

  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.

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device 3 ... Steering shaft 9 ... Deceleration mechanism (worm reduction gear)
10, 10A ... Electric motor 11, 11A ... Control unit (ECU)
15 ... Motor case 16, 16A ... Flange members 16b, 16Ab ... Bolt holes 16c, 16Ac ... Inlay convex part 16Ad ... Overhang part 16Ae ... Long hole 19 ... Motor shaft 25 ... gear box 25c ... inlay recess 25a ... motor mounting surface 26 ... bolt 29 ... worm 30 ... worm wheel 35 ... bus bar terminal 35a ... long hole 36 ... -Bolt C1 ... Concentric circle C2 ... Concentric circle

Claims (4)

An electric power steering apparatus comprising: an electric motor that applies a steering assist force to a steering mechanism via a transmission mechanism housed in a gear box; and a control unit that controls driving of the electric motor,
An outer casing of the electric motor is constituted by a bottomed cylindrical motor case having an open end, and a flange member attached to the motor case so as to close the opening, and the flange member The electric motor is fixed to the gear box through a fastening bolt in a state in which the spigot part formed on the outer surface of the gear box is fitted to the spigot part formed on the motor mounting surface of the gear box,
The plurality of bolt holes through which the fastening bolts are inserted are formed at equal intervals on the same circle around the rotation shaft of the electric motor in the flange member, and
2. The electric power steering apparatus according to claim 1, wherein the bolt hole is an arc-shaped elongated hole having an arc formed along a concentric circle with a rotation axis of the electric motor as a center.   2. The electric power steering apparatus according to claim 1, wherein at least three of the bolt holes are arranged at equal intervals along the same circle centered on the rotation axis of the electric motor. The electric motor and the control unit are electrically connected via a bus bar terminal drawn from a part of the flange member, and
3. The electric power steering apparatus according to claim 1, wherein the control unit is fastened and fixed to an extending portion of the flange member formed so as to extend along a direction in which the bus bar terminal is pulled out.   The connection fixing long hole formed in the bus bar terminal and the fastening fixing long hole formed in the overhanging portion of the flange member are arranged on a concentric circle centering on the rotation shaft of the electric motor. The electric power steering apparatus according to claim 3, wherein each shape is formed in a shape having an arc formed along the concentric circle.

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