JP2000190856A - Electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an adverse effect caused by the abrasion of brushes by arranging the brushes face to face so that their sliding directions are made nearly horizontal, and arranging wiring holes above the brushes. SOLUTION: When a motor 50 and a controller 20 are stored in a common case 30, there is a possibility that the abrasion powder of brushes 58 generated in a motor chamber 39 infiltrates a controller chamber 38. The brushes 58 are arranged to be slid nearly in the horizontal direction, and wiring holes are arranged above the brushes 58. The abrasion powder of the brushes 58 is dropped and accumulated in an area below the brushes 58 in the motor chamber 39, thus the abrasion powder is prevented from infiltrating the controller chamber 38 through the wiring holes and causing the malfunction of the controller 20. When the pinching angle of wiring center lines is set to the range of 60-120 deg. and the height of the wiring holes against the brushes 58 is sufficiently secured, the abrasion powder is effectively suppressed from infiltrating the controller chamber 38 through the wiring holes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electric power steering apparatus for applying an assist force by an electric motor.

[0002]

2. Description of the Related Art Conventionally, as an electric power steering apparatus of this type, an electric motor and its controller are housed in a common case to form a unit as disclosed in, for example, JP-A-9-30434. was there. This eliminates the need for external wiring connecting the controller and the motor, and reduces the influence of radiation noise due to the motor drive current.

[0003]

However, in such a conventional electric power steering apparatus, since the motor and the controller are housed in a common case, abrasion powder of the brush generated in the motor chamber is reduced by the controller. The inconvenience of easily entering the room is conceivable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to suppress an adverse effect due to abrasion powder or the like of a brush in an electric power steering device in which an electric motor and a controller are unitized.

[0005]

According to a first aspect of the present invention, there is provided a motor shaft which rotates in cooperation with a steering mechanism, a commutator which is fixed to the motor shaft and conducts to a coil, a brush which slides on the commutator, and a brush. A motor chamber, a controller for supplying a drive current to the brush, a controller room in which the controller is disposed, a partition wall separating the motor room and the controller room, and a wiring hole passing through the partition wall and connecting a wire connecting the controller and the brush. The present invention is applied to an electric power steering device provided with:

[0006] The sliding direction of the brush is substantially horizontally opposed, and the wiring hole is arranged above the brush.

According to a second aspect of the present invention, in the first aspect, when a straight line connecting the rotation center of the motor shaft and the center of the wiring hole is defined as a wiring center line T, a sandwiching angle θ between the two wiring center lines T is provided.
Is set in the range of 60 to 120 °.

In a third aspect based on the first or second aspect, the rack shaft cooperating with the steering mechanism, a pinion transmitting rotation of the handle to the rack shaft, and an assist pinion transmitting rotation of the motor to the rack shaft. It was prepared.

[0009]

According to the first aspect of the present invention, the abrasion powder of the brush falls in a region below each brush holder in the motor chamber. By arranging it above, it is possible to suppress wear powder from entering the controller chamber through the wiring hole, and prevent malfunction of the controller.

Further, by sliding the brush in a substantially horizontal direction, the vertical vibration of the vehicle is not input in the sliding direction of the brush, so that it is possible to prevent the brush from separating from the commutator and causing a poor contact, and to prevent the motor from malfunctioning. Operation can be stabilized.

In the second aspect of the present invention, the pinching angle θ of the wiring center line T is set in the range of 60 ° to 120 °, and the height of each wiring hole with respect to each brush is sufficiently ensured, so that abrasion powder is reduced. Through the controller room can be effectively suppressed.

In the third aspect of the present invention, the assist pinion for transmitting the rotation of the motor to the rack shaft has a two-pinion type structure provided separately from the pinion for transmitting the rotation of the steering wheel. The degree of freedom of arrangement is increased, and the motors can be easily arranged so that each brush slides in a substantially horizontal direction.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a rack-and-pinion type steering device is configured such that rotation of a steering wheel 1 steered by a driver is controlled by an input shaft 2 and an output shaft 15.
The rack shaft 4 meshing with the pinion 3 is moved in the left and right direction through the right and left directions, so that the direction of the wheels 7 is changed via the left and right tie rods 5 and the knuckle arm 6.

The rack-assist type electric power steering apparatus includes an assist pinion 12 that meshes with the rack shaft 4, and transmits power of the electric motor 50 to the assist pinion 12 to perform power assist.

As means for detecting the steering torque, a torsion bar 16 is interposed between the input side shaft 2 and the output side shaft 15, and a torque sensor 17 for detecting the amount of twist of the torsion bar 16 is provided.

The controller 20 receives a steering torque detection signal sent from the torque sensor 17 and a vehicle speed detection signal sent from a vehicle speed sensor (not shown), and is supplied to the coil of the motor 50 according to these signals. The current is controlled to adjust the output torque (power assist force) of the motor 50.

The controller 20 includes a drive circuit for converting a current from a battery (not shown) into a drive current for the motor 50 and outputting the drive current, a control circuit for processing signals, and the like. Are connected by printed wiring.

As shown in FIG. 2, the motor 50 includes a motor shaft 52 rotatably supported, a coil 55 fixed in the middle of the motor shaft 52, and a coil 55 fixed in the middle of the motor shaft 52. A commutator 57 that conducts, and a pair of brushes 58 that slidably contact the commutator 57 and supply a drive current from the controller 20
And a stator 56 made of a permanent magnet fixed around the coil 55.

The motor shaft 52 is rotatably supported by the case 30 via a bearing 53 at one half thereof and one end of the motor shaft 52 is rotatably supported by the motor housing 40 via a bearing 54. The other end of the motor shaft 52 is connected to the gear housing 3 via the torque limiter 18, for example.
7 through a reduction mechanism including a worm gear 75 and a wheel gear 76 in the shaft 12 of the assist pinion 12.
A and connected to the torque limiter 1
8 to the assist pinion 12. Case 3
0 has a center hole 31 through which the motor shaft 52 passes;
An annular recess 35 into which the bearing 53 is fitted is formed.

As shown in FIG. 3, the motor 50 includes a pair of brush holders 59 for slidably supporting the brushes 58. Each brush holder 59 has a cylindrical holder 6.
3, a rod-shaped brush 58 is slidably fitted to the holder portion 63. The brush 58 is pressed against the commutator 57 by the urging force of the spring 69.

When the vibration of the vehicle is input in the sliding direction of each brush 58, the brush 58
7 may cause poor contact.

As a countermeasure, the brushes 58 are arranged so as to slide in a substantially horizontal direction so that the vertical vibration of the vehicle is not input in the sliding direction of the brushes 58. That is,
Each brush 58 is commutator 57 on a common center line L.
The motor 50 is mounted on the vehicle such that the center line L is substantially horizontal.

Each brush holder 59 is formed of a metal plate, and guides current from the controller 20 to the brush 58 via a pigtail wire 64 in the form of a wire. Each brush holder 59 has a terminal 66 connected to the controller 20;
A terminal 65 to which one end of the pigtail wire 64 is connected;
These are integrally formed. The other end of the pigtail wire 64 is connected to the brush 58.

The motor 50 and the controller 20 constituting the electric power steering apparatus are housed through the common case 30 and are unitized. 2, a motor chamber 39 for accommodating the motor 50 is defined between the motor housing 40 and the motor housing 40 on the right side of the case 30, while the controller 20 is accommodated between the gear housing 37 and the left side of the case 30. A controller room 38 for mounting is defined.

The cylindrical case 30 includes a disk-shaped partition wall 32 that partitions the motor chamber 39 and the controller chamber 38 from each other.
A flange portion 33 into which the motor housing 40 is fitted;
And a flange portion 34 into which the gear housing 37 is fitted, and these are integrally formed using aluminum as a material.

A disk-shaped plate 61 made of an insulating material is provided on the case 30 on the motor chamber 39 side of the partition wall 32 with screws 62.
And the brush holder 59 is attached to the plate 61.
Are combined.

A board 71 of the controller 20 is mounted on the controller room 38 side of the partition wall 32, and a cover 72 made of an insulating material for covering a circuit provided on the board 71 is interposed.

Each terminal 6 is provided on a partition 32 of the case 30.
6, a pair of wiring holes 29 are formed. Each wiring hole 29 penetrates the partition wall 32 and connects the motor room 39 and the controller room 38. The terminals 66 integrally formed on the metal brush holder 59 are inserted through the wiring holes 29, and the respective ends are fixed to terminals (not shown) provided on the controller 20 side by soldering.

By the way, abrasion powder of the brush 58 is generated in the motor chamber 39. When a lot of abrasion powder enters the controller chamber 38 through the wiring hole 29, the controller 20 has
This can cause malfunction.

As a countermeasure, the brushes 58 are arranged so as to slide substantially in the horizontal direction, and the wiring holes 29 are arranged above the brushes 58 so that the abrasion powder of the brushes 58 passes through the wiring holes 29. So as not to enter the controller room 38.

The center of each wiring hole 29 and the motor shaft 52
When the straight line passing through the rotation center O is defined as the wiring center line T, the sandwiching angle θ of each wiring center line T is set in the range of 60 to 120 °, and the height of each wiring hole 29 with respect to each brush 58 is sufficiently secured. I do. In the present embodiment, the wiring center lines T are arranged so as to have a sandwiching angle θ of about 90 ° with each other.

The operation is described below, with the above configuration.

The controller 20 receives steering torque and vehicle speed detection signals, and supplies electric power to the motor 5 according to these signals.
Supply 0. The motor 50 supplies a current supplied from the controller 20 to the coil 55 via the brush holder 59, the pigtail wire 64, the brush 58, the commutator 57, and the like.
To generate a power assisting force corresponding to the electric power.

By arranging the brushes 58 so as to slide in a substantially horizontal direction, the vertical vibration of the vehicle is reduced by the brushes 58.
Is not input in the sliding direction of the
7 can be prevented from coming into contact failure away from the motor 5, and the motor 5
0 operation can be stabilized.

By providing a two-pinion type structure in which the assist pinion 12 is provided separately from the pinion 3, the degree of freedom in disposing the motor 50 in a limited space of the vehicle is increased, and each brush 58 slides in a substantially horizontal direction. It is possible to arrange the motor 50 such that

Since the motor 50 and the controller 20 constituting the electric power steering device are housed in a common case 30 to form a unit, external wiring connecting the controller 20 and the motor 50 becomes unnecessary. Controller 20
The wiring connecting the driving circuit of the brush 58 and the brush 58 is connected to the brush holder 59.
The power transmission loss can be reduced and the voltage drop can be suppressed by using the pigtail wire 64 and the like and shortening it.

However, when the motor 50 and the controller 20 are housed in the common case 30, the motor chamber 39
There is a possibility that abrasion powder of the brush 58 generated in the controller room 38 may enter the controller room 38. In response to this, each brush 58
Are arranged so as to slide substantially horizontally, and each wiring hole 29 is arranged above each brush 58. Brush 5
Since the abrasion powder of No. 8 falls and accumulates in a region below each brush 58 in the motor chamber 39, the abrasion powder is suppressed from entering the controller chamber 38 through the wiring hole 29,
The operation failure of the controller 20 can be prevented.

The sandwiching angle θ of each wiring center line T is 60 to 12
0 ° range, each wiring hole 2 for each brush 58
By ensuring a sufficient height of 9, it is possible to effectively prevent wear powder from entering the controller chamber 38 through the wiring hole 29.

As another embodiment, as shown by a broken line in FIG. 1, the motor 50 may directly drive the pinion 3. Further, the motor 50 may be configured to drive the input side shaft 2 via the gear device 70. In this case, although the degree of freedom in arranging the motor 50 is reduced as compared with the two-pinion type structure in the embodiment, the assist pinion can be eliminated.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view of a motor and the like.

FIG. 3 is a front view of the brush holder and the like.

FIG. 4 is a sectional view of a case and the like.

[Explanation of symbols]

 Reference Signs List 3 Pinion 4 Rack shaft 12 Assist pinion 20 Controller 29 Wiring hole 30 Case 32 Partition wall 38 Controller room 39 Motor room 50 Motor 52 Motor shaft 57 Commutator 58 Brush 59 Brush holder 64 Pigtail wire 66 Terminal

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akira Hirai 1-1-1, Daihatsu-cho, Ikeda-shi, Osaka F-term in Daihatsu Industry Co., Ltd. (Reference) 3D032 CC45 DA15 DA23 EA01 EB11 EC23 3D033 CA02 CA03 CA13 CA16 CA21 5H611 AA03 BB01 BB03 PP01 UA01

Claims (3)

[Claims] A motor shaft rotating in cooperation with a steering mechanism; a commutator fixed to the motor shaft and electrically connected to a coil; a brush slidably in contact with the commutator; a motor chamber in which the brush is disposed; A controller that supplies a drive current to the controller; a controller room in which the controller is disposed; a partition that divides the motor chamber and the controller room; and a wiring hole that passes through the partition and connects the controller and the brush. An electric power steering device, comprising: a brush; a sliding direction of the brush; and a wiring hole disposed above the brush. 2. When a straight line connecting the rotation center of the motor shaft and the center of the wiring hole is defined as a wiring center line T, a sandwiching angle θ between the two wiring center lines T is 60 to 120.
The electric power steering apparatus according to claim 1, wherein the electric power steering apparatus is set in a range of degrees. 3. A rack shaft associated with the steering mechanism, a pinion transmitting rotation of a handle to the rack shaft, and an assist pinion transmitting rotation of the motor to the rack shaft. Item 3. The electric power steering device according to item 1 or 2.