JP2002153021A - Motor and electric power steering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor provided having the function of preventing separation of a wire, connected to a brush from a wire guide hole provided to a brush holder, and also to provide a electric power steering apparatus using the motor. SOLUTION: Width of the wire guide hole 44 can be reduced by providing wire stoppers 44a, 44a projected in the width direction of the wire guide hole 44 to the end part of the wire guide hole 44, the movement of an insulated wire 43 due to the wear of the brush 4 is controlled through the contact with the wire stoppers 44a, 44a, thereby the insulated wire 43 being separated from the wire guide hole 44 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor provided with a brush and an electric power steering device provided with the motor.

[0002]

2. Description of the Related Art A conventional electric power steering apparatus has a steering shaft, and the steering shaft is configured by connecting an input shaft and an output shaft via a torsion bar. The steered wheels are connected to the input shaft side of the steering shaft, and the steering mechanism is connected to the output shaft side.

In an electric power steering apparatus, a torque sensor attached to a steering shaft detects a steering torque applied to an input shaft by rotating a steered wheel in one direction, and a motor based on a detection result of the torque sensor. A control circuit controls a motor driving circuit to control a steering assist motor, and the motor generates a torque according to the magnitude of the steering torque in an action direction of the steering torque, and the torque acts on a transmission mechanism. And the power is transmitted to the output shaft via the output shaft, and the increased rotational force is transmitted from the output shaft to the steering mechanism in the same direction as the rotational direction of the steered wheels.

FIG. 8 is an axial sectional view of a conventional motor, FIG. 9 is an enlarged view of a brush holder used in the motor, and FIG. 10 is a perspective view of the brush holder. In the figure, reference numeral 20 denotes a motor housing. The motor housing 20 has a bottomed cylindrical shape, and its opening side is closed by a substantially disc-shaped lid 21.

[0005] A cylindrical stator 22 is fitted and fixed in the motor housing 20, and a cylindrical rotor 23 is rotatably arranged in the stator 22. The rotor 23 has a rotor shaft 23a, and has an armature winding 23b around the axis of the rotor shaft 23a. One end of the rotor shaft 23a passes through the center of the lid 21 and is connected to the transmission mechanism. The commutator 24 has a cylindrical shape, and includes a plurality of commutator pieces 24a, 24a,... Which are coaxially fitted on the rotor shaft 23a and are insulated from each other and connected to the armature winding 23b.

The brush holder 41 has a box shape having an opening 41b on one side. The brush 4 made of, for example, carbon is accommodated in the opening 41b, and a coil spring 42 is accommodated in the bottom. And is fixed to the inside of the motor of the lid 21. The brush 4 is urged toward the commutator 24 by the elastic force of the coil spring 42, protrudes from the opening 41b of the brush holder 41, and is pressed against the peripheral surface of the commutator 24, whereby the commutator pieces 24a, 24a are pressed. ,... Slide on the brush 4.

The brush 4 is connected to a motor drive circuit (not shown) via a covered conductor 43 (for example, a conductor covered with a synthetic resin) connected to a side surface of the brush 4, and the motor drive circuit is It is connected to a power supply (not shown). The side wall 41a of the brush holder 41 has an opening 4
A lead wire lead-out hole 44 extending from 1b to the bottom surface side is provided, and the covered lead wire 43 is led out from the lead wire lead-out hole 44. As a result, the brush 4
And the movement of the covered conductor 43 is enabled.

In the motor described in detail above, the power from the power source is sent to the brush 4 via the insulated conductor 43, and the brush 4 comes into contact with the peripheral surface of the commutator 24, so that the commutator strip on the peripheral surface is 24a, 24a,.
Is supplied to the armature winding 23b.

[0009]

However, if the brush 4 is excessively worn, the covered conductor 43 which moves toward the commutator 24 along the conductor lead hole 44 with the wear of the brush 4 becomes the conductor lead hole 44. Is detached from the open end of the brush holder 41 on the side of the opening 41b to the outside of the lead wire outlet hole 44, so that the covered lead 43 is provided between the rotating commutator 24 and the fixed brush holder 41. The rotation of the commutator 24 is hindered or stopped by biting the motor, so that the rotation of the motor is hindered or stopped.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has a wire retaining hole for reducing the width of the wire drawing hole near an open end of the wire drawing hole on the opening side of the brush holder. By providing a motor that can prevent movement of a conductor caused by brush wear by retaining the conductor and prevent the conductor from detaching from the lead-out hole, and an electric power steering device including the motor. Aim.

Another object of the present invention is to provide a lead wire retaining hole having a tapered portion which gradually reduces the width of the lead wire hole from the open end of the brush holder toward the bottom side. With this arrangement, a motor can be easily inserted into the lead wire hole when the lead wire is inserted into the lead wire hole from the open end of the lead wire lead hole on the opening side in order to insert the brush into the brush holder. , And an electric power steering device including the motor.

[0012]

The motor according to the first aspect of the present invention has a box shape having an opening on one surface and houses a brush protruding from the opening and pressed against the peripheral surface of the commutator. An opening having an open end on the side of the opening, a long hole-shaped lead-out hole extending from the open end to the bottom surface is provided on the side surface, and the lead connected to the brush is drawn out from the lead-out hole. The brush holder is characterized in that the brush holder is provided with a conductive wire stopper protruding in the width direction of the conductive wire drawing hole near the open end.

A motor according to a second aspect of the present invention is characterized in that the wire retainer includes a brush holder having a tapered portion that gradually reduces the width of the wire lead-out hole from the open end to the bottom side.

According to a third aspect of the present invention, there is provided an electric power steering apparatus including the motor described in claim 1 or 2 and a transmission mechanism for transmitting rotation of the motor to a steering shaft.

In the first and third aspects of the present invention, the lead-out hole is provided near the open end of the brush holder on the opening side.
By providing a wire pull-out that reduces the width of the wire pull-out hole, the movement of the wire due to the wear of the brush is restrained by the wire pull-out, and the wire can be prevented from detaching from the wire pull-out hole, and the detached wire can be prevented. As a result, it is possible to prevent the electric power steering device from stopping functioning due to the rotation of the motor being stopped.

According to the second aspect of the present invention, the lead hole
The brush holder is provided with a wire stopper having a tapered portion that gradually reduces the width of the wire drawing hole from the open end on the opening side to the bottom side, so that the opening of the wire drawing hole can be inserted into the brush holder. When a conductor is inserted into the conductor lead-out hole from the open end on the part side, the conductor can be easily inserted into the conductor lead-out hole.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. Embodiment 1. FIG. 1 is an axial sectional view of a motor according to Embodiment 1 of the present invention, FIG. 2 is an enlarged view of a brush holder portion used in the motor, and FIG. 3 is a perspective view of the brush holder portion. It is.

In the figure, reference numeral 20 denotes a motor housing. The motor housing 20 has a bottomed cylindrical shape, and its opening side is closed by a substantially disc-shaped lid 21. The motor housing 20 is connected to the power steering housing 10 (see FIG. 4) via the lid 21. One end (output side end) of the rotor shaft 23a passes through the center of the lid 21 and the worm 31 It is connected to. A cylindrical stator 22 is fitted and fixed in the motor housing 20, and a cylindrical rotor 23 is rotatably arranged in the stator 22.

The rotor 23 has a rotor shaft 23a and an armature winding 23b around the rotor shaft 23a. The commutator 24 has a cylindrical shape, is coaxially fitted on the rotor shaft 23a, rotates integrally with the rotor shaft 23a, and insulates the plurality of commutator pieces 24a, 24a,. And prepare. The commutator pieces 24a, 24a,... Are connected to the armature winding 23b.

The brush holder 41 has a box shape having an opening 41b on one side. The brush 4 made of, for example, carbon is accommodated in the opening 41b, and a coil spring 42 is accommodated in the bottom. And is fixed to the inside of the motor of the lid 21. The brush 4 includes a coil spring 42
Due to the elasticity of the brushes 41, they are urged toward the commutator 24, protrude from the opening 41b of the brush holder 41, and are pressed against the peripheral surface of the commutator 24, whereby the commutator pieces 24a, 24a,
.. Slide on the brush 4.

The brush 4 is formed to be slightly smaller than the inner dimension of the brush holder 41, and a motor (not shown) is provided via a covered conductor 43 (for example, a conductor insulated with synthetic resin) connected to the side surface of the brush 4. Connected to the drive circuit,
The motor drive circuit is connected to a power supply (not shown).

The side wall 41a of the brush holder 41 is provided with an elongated lead wire hole 44 extending from the opening 41b to the bottom side, and the lead wire hole 44 is provided in the brush holder 41 of the lead wire hole 44. Opposing open ends 44b, 44b are provided on the side of the opening 41b.
In the vicinity of 4b, 44b, there are provided lead wire stoppers 44a, 44a protruding in the width direction of the lead wire hole 44, respectively.

The wire retainers 44a, 44a have tapered portions 44c, 44c facing each other.
On the sides of the open ends 44b and 44b of c and 44c, there is provided an interval at which the covered conductor 43 can be sufficiently inserted, and on the bottom side, an interval slightly smaller than the diameter of the covered conductor 43. In addition, the wire removal stoppers 44a, 44a have flat portions at the ends on the bottom side in the width direction of the wire lead-out hole 44.

The brush holder 41 has a lead-out hole 44.
From which the coated conductor 43 is led. This enables the brush 4 and the covered conductor 43 to move with the wear of the brush 4.

When the brush 4 is pressed against the peripheral surface of the rotating commutator 24, the brush 4 is worn and its entire length is shortened. The contact surface is pressed against the peripheral surface of the commutator 24, and the contact between the commutator 24 and the brush 4 is maintained.

At this time, the insulated conductor 43 moves toward the commutator 24 along the conductor lead hole 44 because the conductor lead hole 44 is provided in the side wall part 41a. In the vicinity of 44b, 44b, a spacing slightly smaller than the diameter of the covered conductor 43 is provided to reduce the width of the conductor lead-out hole 44.
By providing a, the movement of the insulated conductor 43 caused by the abrasion of the brush 4 can be restrained by the conductor removal stoppers 44a, 44a, and the insulated conductor 43 can be prevented from being detached from the conductor drawing hole 44.

Also, a wire lead-out hole 44 of the covered wire 43 is provided.
By preventing the conductor 43 from being detached from the wire, the covered conductor 43 can be prevented from biting into the commutator 24. In addition, the movement of the insulated conductor 43 caused by the abrasion of the brush 4 is prevented from coming off the conductor 44a,
Stopping at 44a makes it impossible for the brush 4 to come into contact with the peripheral surface of the commutator 24 and stops the current, so that the motor 2 stops rotating. When the motor 2 stops, a motor control circuit (not shown) detects the abnormality and issues a warning to the driver.

Further, the wire stoppers 44a, 44a have tapered portions 44c, 44c facing each other, and the covered wire 43 can be sufficiently inserted into the tapered portions 44c, 44c on the side of the open ends 44b, 44b. Since the interval is slightly smaller than the diameter of the covered wire 43 on the bottom side, the open end portions 44b, 4b of the wire lead hole 44 for inserting the brush 4 into the brush holder 41 are provided.
When inserting the covered conductor 43 into the conductor lead hole 44 from the 4b side, the sheath conductor 43 can be easily inserted into the conductor lead hole 44 by slightly pressing the insulator covering the conductor 43. Can be.

FIG. 4 is a longitudinal sectional view of the electric power steering apparatus according to Embodiment 1 of the present invention, and FIG. 5 shows the configuration of a transmission mechanism and a motor portion used in the electric power steering apparatus. FIG. 4 is a sectional view perpendicular to the steering shaft.

In the figure, reference numeral 1 denotes a steering shaft, and the steering shaft 1 is configured by connecting an input shaft 12 and an output shaft 14 via a torsion bar 13. The steering wheel 11 is connected to the input shaft 12 side (upper side) of the steering shaft 1, and a steering mechanism (not shown) is connected to the output shaft 14 side (lower side). The steering shaft 1 is provided with a torque sensor 15 for detecting a steering torque applied to the input shaft 12 by a relative angular displacement of the input shaft 12 and the output shaft 14 in the rotation direction caused by the intervention of the torsion bar 13. The motor control circuit controls the motor drive circuit based on the detection result of the torque sensor 15 to control the rotational force of the steering assist motor 2.

The motor 2 has a torque sensor 15 and a transmission mechanism 3 having a worm 31 and a worm wheel 32.
One end of a rotor shaft 23a, which is an output shaft of the motor 2, is connected to a shaft of one end of a worm 31 which is arranged to be orthogonal to the axis of the output shaft 14. Have been. Warm 3
The tooth portion of the worm wheel 32 fitted and fixed in the middle of the output shaft 14 of the steering shaft 1 meshes with the center of the one tooth portion.

In such an electric power steering apparatus, when the steered wheels 11 rotate in one direction, the input shaft 12 and the output shaft 14 generated by the intervention of the torsion bar 13 are provided.
The torque sensor 15 detects a steering torque applied to the input shaft 12 based on the relative angular displacement in the rotational direction of the motor 2. Based on the detection result of the torque sensor 15, the motor 2 determines the magnitude of the steering torque in the direction in which the steering torque acts. , And the torque is transmitted to the worm 31 and the worm 3
1 rotates and the worm wheel 32 rotates with the rotation of the worm 31, whereby the rotational force is increased and transmitted to the output shaft 14, and the steering wheel 11 is transmitted from the output shaft 14 to a steering mechanism. It is configured such that the increased rotational force is transmitted in the same direction as the rotational direction.

The electric power from the power source is supplied to the
3 to the brush 4, which brush 4
Of the commutator piece 24 on the peripheral surface by contacting the peripheral surface of the
The electric power is supplied by transmitting the electric power to the armature winding 23b of the rotor 23 via a, 24a,.

At this time, the wire pull-out holes 44 of the brush holder 41 are provided with wire pull-offs 44a, 44a, and the movement of the covered wire 43 caused by the wear of the brush 4 is restricted by the wire pull-outs 44a, 44a. , Brush 4
Is unable to contact the peripheral surface of the commutator 24 and the current stops flowing, so that the motor 2 stops rotating. However, the covered conductor 43 is detached from the conductor lead hole 44 and the commutator 2
4 can be prevented from biting. When the motor 2 stops, the worn brush 4 is replaced.

Embodiment 2 FIG. 6 is an enlarged view of a brush holder part used in motor 2 according to Embodiment 2 of the present invention.

The side wall portion 51a of the brush holder 51 is provided with an elongated lead-out hole 54 extending from the opening 51b to the bottom surface side. The lead-out hole 54 is provided in the brush holder 51 of the lead-out hole 54. Have open ends 54b, 54b facing each other on the side of the opening 51b, and near the open ends 54b, 54b, substantially semicircular conductive wire stoppers 54a, 54a protruding in the width direction of the conductive wire drawing hole 54.
Are provided.

The wire retainers 54a, 54a have oppositely tapered arc-shaped tapered portions 54c, 54c. The curvatures of the tapered portions 54c, 54c are small and the curvature on the bottom side is large. In addition, the open ends 54b of the tapered portions 54c, 54c,
An interval where the covered conductor 43 can be sufficiently inserted is provided on the 54b side, and an interval slightly smaller than the diameter of the covered conductor 43 is provided on the bottom side.

Since the wire retainers 54a, 54a do not have a sharp top, the coated conductor 43 is not damaged,
It can be inserted more easily than the lead wire stoppers 44a, 44a of the first embodiment.

The gear used for the transmission mechanism of the electric power steering apparatus according to the first or second embodiment described above may be not only a worm and a worm wheel but also a hypoid pinion and a hypoid wheel.

Embodiment 3 FIG. 7 is an axial sectional view of a motor 2 according to Embodiment 3 of the present invention. The configuration of the electric power steering device and the transmission mechanism and the motor portion used in the electric power steering device according to the third embodiment are used in the electric power steering device and the electric power steering device according to the first or second embodiment. The configuration is substantially the same as the configuration of the transmission mechanism and the motor portion, and includes a slide bearing 20c and a flange 23c provided on the rotor shaft 23a.

The rotor shaft 23a has an output end on a rolling bearing 21b supported by a bearing support 21a, a non-output end on a slide bearing 20c supported on a bearing support 20a,
Each is rotatably supported. Worm 31 for transmission mechanism 3
And the worm wheel 32, the rotor shaft 23
One end of “a” is connected to the worm 31. At this time, the axial load and the radial moment generated in the worm 31 are absorbed by the joint between the worm 31 and the rotor shaft 23a, and do not interfere with the rotor shaft 23a. For this reason,
The end of the rotor shaft 23a can be supported by a sliding bearing 20c instead of a conventionally used rolling bearing.

The motor 2 according to the third embodiment has a configuration in which a non-output side end of the rotor shaft 23a is supported by a sliding bearing 20c. In this case, the sliding bearing 20c has a smaller number of parts than the rolling bearing, and has a small size in the axial direction and small bearing play (gap in the axial direction). Therefore, the size of the motor housing 20 in the axial direction is reduced. Motor housing 20
Interference with the vehicle body can be prevented. In addition, the sliding bearing 2
0c has a smaller size in the radial direction and smaller bearing play (gap in the radial direction) than the rolling bearing, so that the size of the motor housing 20 in the radial direction is reduced.
0 can be prevented from interfering with the vehicle body.

Further, in the rolling bearing, it is necessary to prevent a frictional resistance of the motor housing 20 from being applied to the rolling bearing by providing a bearing play between the rolling bearing and the motor housing 20. For this reason, when an axial load or a radial moment is generated on the rotor shaft 23a and the rotor shaft 23a is rocked, the rolling bearing may come into contact with the motor housing 20 to generate rocking noise. . However, the sliding bearing 20c is
Since there is no need to provide a gap between the motor housing 20 and the motor housing 20, the rocking noise can be reduced.

Since the sliding bearing 20c is made of, for example, a metal, worn metal powder flows out of a gap between the bearing support 20a and the rotor 23, and the sliding between the rotor 23 and the stator 22 is performed. In some cases, it may penetrate between the rotors 23 and bite between the rotor 23 and the stator 22 to hinder the rotation of the rotor 23 and deteriorate the performance of the motor 2. For this reason, a disk-shaped flange 23c is provided at the end of the rotor shaft 23a on the bearing support portion 20a side to prevent the metal powder from flowing out, and the sliding bearing 20c and the flange 23c are provided.
The metal powder is stored in the gap between the metal powder and the metal powder.

The motor according to any one of the first to third embodiments of the present invention may be provided in an electric device other than the electric power steering device.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a motor according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view of a brush holder used in the motor according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a brush holder used in the motor according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of the electric power steering device according to Embodiment 1 of the present invention.

FIG. 5 is a cross-sectional view perpendicular to the steering shaft, showing a configuration of a transmission mechanism and a motor portion used in the electric power steering device according to the first embodiment of the present invention.

FIG. 6 is an enlarged view of a brush holder used in a motor according to Embodiment 2 of the present invention.

FIG. 7 is an axial sectional view of a motor according to a third embodiment of the present invention.

FIG. 8 is an axial sectional view of a conventional motor.

FIG. 9 is an enlarged view of a brush holder used in a conventional motor.

FIG. 10 is a perspective view of a brush holder portion used in a conventional motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steering shaft 2 Motor 24 Commutator 3 Transmission mechanism 4 Brush 41 Brush holder 41a Side wall part 43 Insulated lead wire 44 Lead wire lead hole 44a Lead wire stopper 44b Open end part 44c Taper part 51 Brush holder 51a Side wall part 54 Lead wire lead hole 54a Lead wire missing Stop 54b Open end 54c Taper

Claims (3)

[Claims] 1. A box shape having an opening on one surface, a brush projecting from the opening and pressed against a peripheral surface of a commutator is housed, and the opening has an open end on the opening side. A motor provided with a long hole-shaped lead-out hole extending from an end to a bottom surface side, and a brush holder leading out a lead connected to the brush from the lead-out hole, wherein the brush holder has the open end A motor provided with a wire stopper protruding in the width direction of the wire drawing hole near the portion. 2. The motor according to claim 1, wherein the wire retainer includes a brush holder having a tapered portion that gradually reduces the width of the wire lead-out hole from the open end to the bottom surface side. 3. An electric power steering apparatus comprising: the motor according to claim 1; and a transmission mechanism that transmits rotation of the motor to a steering shaft.