JP3207177B2 - Commutator motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a commutator motor provided with a brush device having a pigtail whose one end is connected to a brush.

[0002]

2. Description of the Related Art FIG. 2 is a front view of a brush device incorporated in a motor for a power steering device which is a conventional commutator motor, and FIG. 3 is a side sectional view taken along the line III-III of FIG. The commutator motor includes a cylindrical yoke, a field permanent magnet fixed in the yoke, a shaft rotatably provided by a bearing in the yoke, an armature fixed to the shaft, and an end of the shaft. A brush device 4 fixed to a housing 2 having a through hole 1 through which a shaft passes by a fastening screw 3, and a grommet 6 elastically locked in a cutout 5 of the housing 2. When,
And a lead wire 7 penetrating the grommet 6. The brush device 4 includes a base 10 in which a conductor 9 is embedded by insert molding, two metal brush holders 11 fixed to the base 10, and a brush holder 1.
And brushes 13a and 13b held in the brush 1 and contacting the commutator by the elastic force of the spring 12, and each of the brushes 13a and 1b.
3b has one end connected thereto and the other end connected to the connection portion 15 of the conductor 9.
and pigtails 14a, 14b connected to the conductor 9 by welding at a, 15b. This pigtail 14
a and 14b are composed of an annealed copper wire, an annealed copper wire or the like.

[0003] The brush device 4 is assembled in the following procedure. First, the conductor 9 is placed in a mold, a synthetic resin is injected, and the conductor 9 and the base 1 are inserted by insert molding.
0 is integrated. Thereafter, the brush holder 11 is locked to the base 10, and the ends of the pigtails 14a, 14b are welded to the connecting portions 15a, 15b. Next, the spring 12 is put in the brush holder 11, and the brushes 13a and 13b are assembled in the brush holder 11.

In the commutator motor, an electric current is supplied to the armature from the outside via the brushes 13a and 13b which come into contact with the commutator, so that the armature rotates together with the shaft by electromagnetic action.

[0005]

In the commutator motor having the above structure, as shown in FIG.
5b is not at the line symmetric position of the center line A extending in the radial direction passing through the rotation center of the shaft . This is because there is no room in the space due to the area of the current circuit area of the conductor 9 connecting the lead wire 7 and the brushes 13a and 13b, so that the configuration is such. The pigtails 14a and 14b are
If the length is changed, the number of parts increases, so that the length is the same. For this purpose, the brushes 13a, 13b and the connecting portion 15
As a result of the different distance between the pigtails 14a and 15b, the pigtail 14
The slack shapes of a and 14b are different from each other. As a result, for example, in the motor for the electric power steering device in which the load of the spring 12 is set small and the pressing force of the brushes 13a and 13b on the commutator segments is reduced as much as possible, particularly to reduce the loss torque, the pigtails 14a and
The brushes 13a, 13b
However, there is a problem in that the contact state of the commutator with the segment is different, the brush sound is different between the brushes 13a and 13b, and the brush sound is different even when the shaft is rotated in the normal or reverse direction, which is unstable.

The brush device 20 shown in FIG.
One end of each of pigtails 22a, 22b, 22c, 22d connected to each of the brushes 21a, 21b, 21c, 21d has four bases 1a, 21b, 21c, 21d.
The point extending in the circumferential direction of 0 (so-called horizontal protrusion) is different from the brush device 4 in FIG. In this case also, the connection portions 23a of the conductor 9, 23b, 23c, 23d is Shah
Since the center lines A and B extending in the radial direction passing through the center of rotation of the shaft are not located in line symmetry, there is a problem similar to that of the brush device 20 of FIG. In particular, in this case, the pigtail 22
Since one ends of the a, 22b, 22c, and 22d are so-called sideways, the distance between the connecting portions 23a, 23b, 23c, and 23d and the brushes 21a, 21b, 21c, and 21d is short. , 22c, and 22d become larger than in the case of the so-called vertical extension shown in FIG. 2, and are more affected by the above problem. Also, pigtails 22a, 22b, 22c, 22
Since the pressing force on the brushes 21a, 21b, 21c, 21d by d is in the circumferential direction of the commutator, the brushes 21a, 21b, 21c,
Since the abutment state of the 21d with the commutator changes and becomes unstable, the above-mentioned problem is further affected.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a commutator motor capable of reducing brush noise variation between brushes and brush noise. .

[0008]

According to a first aspect of the present invention, there is provided a commutator motor according to the present invention, wherein each connecting portion of a conductor connected to the other end of each pigtail, and a brush pass through a rotation center of a shaft in a radial direction. Are arranged at symmetrical positions with respect to the center line extending in the direction of the arrow.

Further, in the commutator motor according to claim 2,
There are four brushes.

[0010] In the commutator motor according to the third aspect,
The number of commutator segments is an even number.

Further, in the commutator motor according to claim 4,
The conductor is embedded in a synthetic resin base, and the conductor and the base are integrally formed by insert molding.

Further, in the commutator motor according to claim 5,
One end of the pigtail extends in the axial direction of the base.

Further, in the commutator motor according to claim 6,
A commutator motor is a motor for an electric power steering device.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a front view of a brush device 30 incorporated in a motor for an electric power steering device which is a commutator motor of the present invention. The same or corresponding members as those in FIGS. 2 to 4 are denoted by the same reference numerals and described. The commutator motor includes a cylindrical yoke, a field permanent magnet fixed in the yoke, a shaft rotatably provided by a bearing in the yoke, an armature fixed to the shaft, and an end of the shaft. A brush device 30 fixed to a housing 2 having a through hole 1 through which a shaft penetrates, with a fastening screw 3, and a grommet 6 elastically locked in a notch 5 of the housing 2. And a lead wire 7 penetrating the grommet 6.

The brush device 30 includes a base 35 in which a conductor 36 is embedded by insert molding, four metal brush holders 31 fixed to the base 35, and a spring 12 held in the brush holder 31. Brushes 32a, 32b, 32c, which contact the commutator by elastic force,
32d and one end of each of the brushes 32a, 32b, 32c, 32d, and the other end of each of the connecting portions 34a, 34 of the conductor 36.
4b, 34c, 34d and a plurality of pigtails 33a, 33b, 33 each having the same length.
c, 33d. Brushes 32a, 32b, 3
2c, 32d and connecting portions 34a, 34b, 34c, 34
d is at a line symmetrical position with respect to the center lines A and B extending in the radial direction passing through the rotation center of the shaft . In addition, in order to arrange in this manner, the lead wire 7 and the brushes 32a, 32b, 32
The shape of the base 35 and the conductor 36 is larger than that of the conventional one due to the area of the current circuit of the conductor 36 connecting the terminals c and 32d.

In the brush device 30 having the above structure, the brush 3
2a, 32b, 32c, 32d and connecting portions 34a, 34
Since b, 34c, and 34d are located at line-symmetric positions of center lines A and B extending in the radial direction passing through the rotation center of the shaft , the pigtails 33a, 33b, and 33g have the same length.
Since the slack shapes of the brushes 33c and 33d can be made the same, the variation in the pressing force on the commutator among the brushes 32a, 32b, 32c and 32d can be reduced, and the variation in the brush sound can be reduced. Further, in a motor having a small load on the spring 12, such as a motor for an electric power steering device that rotates in a clockwise direction and a counterclockwise direction, in particular, a variation in the pressing force applied to the commutator between the brushes 32a, 32b, 32c, 32d. The reduction of the variation of the brush sound and the variation of the brush sound between both rotation directions are remarkable.

By setting the number of commutator segments to an even number, the four brushes 32a, 32b, 32c, 3
The contact state at the position where 2d contacts each segment is the same, and each brush 32a, 32b, 32c, 32
The variation of the brush sound between d is further reduced. The conductor 36 is embedded in a base 35 made of synthetic resin.
And the base 35 are integrally formed by insert molding, so that the structure is simple and the conductor 3
6 and the peripheral parts are secured. Further, since one ends of the pigtails 33a, 33b, 33c, 33d protrude in the axial direction of the base 35, the one ends of the pigtails 22a, 22b, 22c, 22d are so-called sideways as shown in FIG. In the clockwise and counterclockwise directions of the commutator, the brushes 32a, 32b, 32c,
The change in the state of contact with the 32d commutator is reduced.

[0018]

As described above, in the commutator motor according to the first aspect of the present invention, each connecting portion of the conductor connected to the other end of each pigtail having the same length, and each brush, Since the brushes are arranged at line-symmetrical positions of the center lines extending in the radial direction passing through the center of rotation of the shaft, the variation in abutting state of the commutator between the brushes can be reduced. The variation in sound can be reduced, and the brush sound can be reduced.

Further, in the commutator motor according to the second aspect,
Four brushes are placed at the line target position of the center line,
It is possible to reduce the variation of the brush sound among the four brushes, and to reduce the brush sound caused by the four brushes.

Further, in the commutator motor according to the third aspect,
Since the number of commutator segments is an even number, the contact state at the point where each brush contacts the segment is the same,
It is possible to reduce the variation of the brush sound between the brushes and to reduce the brush sound.

Further, in the commutator motor according to the fourth aspect,
Since the conductor is embedded in a synthetic resin base, and the conductor and the base are integrally formed by insert molding, the structure is simple and the insulation between the conductor and the peripheral components is ensured. When the base is fixed to the housing and the lead wire and the pigtail are welded to the conductor integrated with the base, even if the lead wire is moved from the outside, the pigtail is not affected and the brush sound does not change.

Further, in the commutator motor according to claim 5,
Since one end of the pigtail protrudes in the axial direction of the base, the contact state of the brush with the commutator in the clockwise and counterclockwise directions of the commutator is smaller than when the one end of the pigtail is so-called laterally protruding. The change is small, the variation of the brush sound between the brushes can be reduced, and the brush sound can be reduced.

Further, in the commutator motor according to claim 6,
As the commutator motor is applied to a motor for an electric power steering device in which the pressing force of the brush abutting on the commutator is small, the variation of the brush sound between the brushes and the reduction of the brush sound are more remarkable.

[Brief description of the drawings]

FIG. 1 is a front view of a brush device incorporated in a commutator motor according to Embodiment 1 of the present invention.

FIG. 2 is a front view of a brush device incorporated in a conventional commutator motor.

FIG. 3 is a side sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a front view showing another example of a brush device incorporated in a conventional commutator motor.

[Explanation of symbols]

2 housing, 7 lead wires, 30 brush device, 3
1 brush holder, 32a, 32b, 32c, 32d
Brush, 33a, 33b, 33c, 33d pigtail, 34a, 34b, 34c, 34d connection, 35
Base, 36 conductors.

Continued on the front page (56) References JP-A-6-74076 (JP, U) JP-A-6-74063 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 13 / 00

Claims (6)

(57) [Claims] 1. A shaft, a housing having a through hole through which the shaft passes, an armature fixed to the shaft, a commutator fixed to an end of the shaft, a base integrated with the housing, and a base. A brush device including a plurality of brushes each having a fixed length, a plurality of brushes abutting on the commutator, and a plurality of pigtails having the same length and one end connected to each brush and the other end connected to the conductor; A lead wire electrically connected to a conductor and supplying a current to each of the brushes via the conductor; anda connection portion of the conductor connected to the other end of each pigtail, and each of the brushes , The shaft
The commutator motor is disposed at a position symmetrical with respect to a center line extending radially through the rotation center of the motor. 2. The commutator motor according to claim 1, wherein the number of brushes is four. 3. The commutator motor according to claim 1, wherein the commutator has an even number of segments. 4. The conductor is embedded in a synthetic resin base,
The commutator motor according to any one of claims 1 to 3, wherein the conductor and the base are integrally formed by insert molding. 5. The commutator motor according to claim 1, wherein one end of the pigtail projects in the axial direction of the base. 6. The commutator motor according to claim 1, wherein the commutator motor is a motor for an electric power steering device.