JP2003079093A - Brush device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brush device that allows brush vibration noise to be suppressed. SOLUTION: The brush device 7 is provided with brushes 16, coil springs, brush holders 18, and a substrate 19. The brush 16 is roughly rectangular parallelepiped in form, with the front end in slidable contact with the outer periphery of a commutator 12 roughly cylindrical in form. The coil spring biases the brush toward the commutator 12. The brush holder 18 stores and holds the brush 16 and the coil spring. The substrate 19 secures the brush holders 18 in the end housing 4. Pigtails 26 are affixed in two locations that are symmetrical to the circumferential center of the commutator 12 on the back end of the upper surface of the brush. The driving current of a motor 1 is supplied to the brushes 16 through the pigtails 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush device for slidingly contacting a brush with a commutator.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
The brush device 42 of No. 1 includes a brush 43 and a brush holder 44.
And a coil spring 45. Further, a commutator 47 is provided on the rotary shaft 46 of the DC motor 41,
The tip surface of the brush 43 is brought into sliding contact with the commutator 47.

More specifically, the brush 43 has a rectangular parallelepiped shape, is accommodated in a rectangular cylindrical brush holder 44, and is held in a state of being urged toward the commutator 47 by a coil spring 45. Further, a pigtail (power supply lead wire) 48 is connected to the brush 43, and the pigtail 48 is connected to a power supply via a power supply terminal (not shown). Then, power is supplied to the commutator 47 via the pigtail 48 and the brush 43, and the rotor 49 (the rotation shaft 46, the commutator 47, etc.) of the motor 41 is rotated.

By the way, when the motor 41 is driven for a long time, the contact resistance between the brush 43 and the commutator 47 causes the brush 43 to reach a high temperature and thermally expand. Therefore, the brush holder 44 is designed in consideration of the thermal expansion of the brush 43. That is, the storage space in the brush holder 44 is slightly larger than the brush 43 in the cold state (normal temperature), and there is a gap between the brush holder 44 and the brush 43. By providing this gap, it is possible to prevent the movement of the brush 43 in the front-rear direction from being hindered by the inner wall of the brush holder 44 even if the brush 43 becomes hot and thermally expands.

[0005]

However, since there is a gap between the brush holder 44 and the brush 43, the motor 4
When driving 1, the frictional force between the tip surface of the brush 43 and the commutator 47 fluctuates, and the brush 43 vibrates in the circumferential direction of the commutator 47. Specifically, as shown by the chain double-dashed line in FIG. 9, one edge (the end opposite to the rotation direction X) at the tip of the brush is a line in the height direction of the brush 43 (the direction orthogonal to the paper surface in FIG. 9). They come into contact and the other edge rises. As a result, brush vibration is generated, and the vibration causes the brush 43 to strike the inner wall of the brush holder 44, resulting in a striking sound (noise). In particular, in the brush 43, the pigtail 48 has the commutator 4
Since it is fixed to the position at the center in the circumferential direction of 7, the brush vibration becomes large with the pigtail 48 as a fulcrum.
Therefore, in the brush device 42, brush vibration is likely to occur,
This causes noise.

The present invention has been made to solve the above problems, and an object thereof is to provide a brush device capable of suppressing brush vibration and noise.

[0007]

According to a first aspect of the present invention, there is provided a brush having a substantially rectangular parallelepiped shape, a tip of which is in sliding contact with an outer peripheral surface of a commutator, and a brush which stores and holds the brush. In a brush device including a holder, a spring for urging the brush toward the commutator, and a power supply lead wire for supplying a drive current of a motor to the brush, the brush device is provided with a peripheral portion more than a radial direction of the commutator. The power supply lead wire was fixed with a width in the direction.

According to a second aspect of the present invention, in the brush device according to the first aspect, the power supply lead wire is provided on the upper surface of the brush in the axial direction of the commutator, and the center of the upper surface of the brush in the circumferential direction of the commutator. Fixed symmetrically with respect to.

According to a third aspect of the present invention, in the brush device according to the second aspect, the power supply lead wire is located near the circumferential end of the commutator on the upper surface of the brush with respect to the circumferential center. It is fixed at two points that are symmetrical positions.

According to a fourth aspect of the present invention, in the brush device according to the first aspect, the power supply lead wire is fixed at a plurality of points of the brush, and at least one of the power supply lead wire is fixed. , On the side of the brush in the circumferential direction of the commutator.

(Operation) According to the invention described in claim 1,
In the brush, the power supply lead wire is fixed with a width in the circumferential direction rather than the radial direction of the commutator. In this case, the brush vibration with the fixed portion of the power supply lead wire as a fulcrum is suppressed, and the hitting noise (noise) due to the brush vibration is suppressed.
Further, since the vibration of the brush can be suppressed, the fluctuation of the contact resistance between the brush and the commutator is suppressed, and the fluctuations of the motor torque and the rotation speed are reduced.

According to the second aspect of the present invention, since the power supply lead wire is fixed to the same brush upper surface, the brush device can be easily manufactured. In addition, since the power supply lead wires are fixed symmetrically with respect to the center of the commutator in the circumferential direction on the upper surface of the brush, brush vibration can be appropriately suppressed.

According to the third aspect of the invention, since the fixing portion of the power supply lead wire is at two places, the manufacturing of the brush device becomes easier. Further, since the fixing portion of the power supply lead wire is near the end portion of the brush upper surface, brush vibration can be effectively suppressed. Further, even if one of the fixing portions of the power supply lead wire is cut off, the current supply can be maintained by the other.

According to the fourth aspect of the present invention, at least one of the power supply lead wires is fixed on the side surface of the brush in the circumferential direction of the commutator. Vibration can be suppressed more effectively. Further, even if one of the fixing portions of the power supply lead wire is disconnected, the current supply can be maintained.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a main part of a DC motor 1 according to this embodiment, and FIG.
It is a principal part sectional view in the -A line.

As shown in FIG. 2, the housing 2 of the DC motor 1 has a substantially bottomed cylindrical yoke housing 3 and an end housing 4 that covers the opening of the yoke housing 3.
Consists of. The DC motor 1 includes a plurality of magnets 5, a rotor 6, a brush device 7 and the like in a housing 2. Specifically, a plurality of magnets 5 are fixed to the inner peripheral surface of the yoke housing 3.
A rotor 6 is rotatably supported on the inner side of. The rotor 6 includes a rotating shaft 9 and a core 10 fixed to the rotating shaft 9.
And a coil 11 wound around the core 10 and a substantially cylindrical commutator (commutator) 12, and a rotating shaft 9 of the rotor 6 is rotatably supported by a bearing 13 fixed to the housing 2. ing. A commutator 12 is fixed to an end of the rotary shaft 9 so as to be rotatable integrally with the rotary shaft 9. The commutator 12 has a plurality of segments (commutator pieces) 14, and each segment 14 has a coil 11
Are connected.

A brush device 7 is disposed in the end housing 4 at a position adjacent to the commutator 12. The brush device 7 includes a brush 16 having a substantially rectangular parallelepiped shape.
And a coil spring 17 that contacts the rear end surface of the brush 16 and urges the brush 16 toward the commutator 12.
A brush holder 18 for housing and holding the brush 16 and the coil spring 17, and a resin substrate 19 for fixing the brush holder 18 to the end housing 4. A hole 20 is formed in the board 19, and a screw hole 21 communicating with the hole 20 is formed in the end housing 4. Then, by screwing the screw 22 into the screw hole 21 of the end housing 4 through the hole 20 formed in the substrate 19, the substrate 19 (brush device 7) is moved to the end housing 4.
It is fixed to.

As shown in FIG. 1, on a substrate 19, four square-shaped cylindrical brush holders 18 are provided at equal intervals, and four (two pairs) brushes 16 are in sliding contact with the commutator 12. . The board 19 is provided with a power supply plate (not shown) for distributing the positive and negative electrodes to each brush 16 by insert molding, and the terminals 23 to be joined of the power supply plate project from the board 19. A pair is formed so that An external lead wire 24 is joined to each joined terminal 23 by spot welding or the like. The external lead wire 24 is
It is composed of two lead wires, one lead wire is connected to the + pole of the DC drive power source (not shown), and the other lead wire is connected to the-pole.

Further, a groove (slit) 18a is formed on the upper surface of the brush holder 18 along the longitudinal direction of the holder 18, and a pigtail (feeding lead wire) 26 is taken out through the slit 18a. . The pigtail 26 is a strand of annealed copper, one end of which is connected to the power supply plate of the substrate 19, and the other end of which is the brush 16.
It is connected to the.

As shown in FIGS. 1 and 3, the end of the pigtail 26 in this embodiment is bifurcated.
These two ends are embedded and fixed on the rear end side of the upper surface of the brush 16. More specifically, as shown in FIG. 3, the end of the pigtail 26 is fixed at two positions in the upper surface 16 a of the brush 16 in the vicinity of the end of the commutator 12 in the circumferential direction and at symmetrical positions with respect to the center of the circumferential direction. Has been done. The two fixing parts of this pigtail 26 are
It is provided so as to be parallel to the tangent line between b and the commutator 12. That is, the fixed portion of the pigtail 26 is juxtaposed in the tangential direction with the commutator 12.
The brush 16 has a brush upper surface 16a in the axial direction of the commutator 12 (axial direction of the motor 1) and a brush side surface 16a.
The brush holder 18 is housed in the brush holder 18 such that c is located in the circumferential direction of the commutator 12 (the circumferential direction of the motor 1).

As described above, fixing the pigtails 26 at two locations suppresses brush vibration. That is, as shown in FIG. 4A, when the pigtail 48 is fixed at one position at the center of the brush 43 in the circumferential direction (in the case of the conventional brush device 42), the pigtail 48 of the commutator 47 is rotated. A moment is applied to the brush 43 around the fixed portion. That is, the rotational moment M that causes the brush edge to rise is increased. On the other hand, in the present embodiment, as shown in FIG. 4B, the pigtail 26 is fixed at two positions in the brush 16 while avoiding the position at the center in the circumferential direction. In other words, the two ends of the pigtail 26 are fixed at a predetermined interval, and the pigtail 26 is fixed with a width in the circumferential direction rather than the radial direction of the commutator 12, so that the rotation moment that causes the brush edge to rise M is suppressed and brush vibration is suppressed.

Further, in this embodiment, as shown in FIG.
The tip surface 16b of the brush 16 is slightly recessed toward the center in the height direction. Further, the corner of the commutator 12 in the circumferential direction at the tip of the brush 16 is chamfered. By forming the brush 16 in this manner, the contact between the brush tip surface 16b and the commutator 12 during the initial use of the motor 1 becomes good, and the brush edge is prevented from rising.

As described in detail above, this embodiment has the following features. (1) On the brush upper surface 16a, the pigtails 26 are fixed at two locations in the vicinity of the circumferential end of the commutator 12 and at symmetrical positions with respect to the circumferential center. With this configuration, the rotational moment M that causes the brush edge to rise is suppressed, and the brush vibration can be suppressed. Further, since the brush vibration can be suppressed, it is possible to suppress the fluctuation of the contact resistance between the brush 16 and the commutator 12. Therefore, it is possible to realize the DC motor 1 having a small fluctuation in the motor torque and the rotation speed and having a good commutation characteristic. That is, the high-performance DC motor 1 that can be stably driven can be realized.

(2) Since the pigtails 26 are fixed at two points on the brush upper surface 16a, the brush device 7 can be easily manufactured and the manufacturing cost can be suppressed. Further, since the fixed portion of the pigtail 26 is near the end of the brush upper surface 16a, brush vibration can be effectively suppressed.

(3) Since the fixing portion of the pigtail 26 is plural (two places), the stress applied to the fixing portion of the pigtail 26 by external force such as motor vibration can be dispersed. Further, the tension of the pigtail 26 with respect to the brush 16 and the direction thereof can be easily adjusted. Further, even if one of the fixing portions of the pigtail 26 is cut off, the current supply can be maintained by the other.

In addition to the above, the present invention can be embodied in the following forms. In the brush device 7 of the above-described embodiment, the pigtail 26 is embedded and fixed at two positions on the brush upper surface 16a, but the invention is not limited to this. The brush device of the present invention may be any device as long as it has a width in the circumferential direction of the brush 16 rather than the radial direction of the commutator 12 and fixes the pigtail. Specifically, for example, as shown in FIG. 5, the end of the pigtail 27 is divided into three parts, and the ends are fixed so as to be parallel to the tangent line between the brush 16 and the commutator 12 on the brush upper surface 16a. You may. Further, as shown in FIG. 6, the pigtail 28 is made extremely thin and divided into a large number, and the plurality of divided pigtails 28 are fixed linearly so as to be parallel to the tangent line between the brush 16 and the commutator 12. Good. In addition, the pigtail 28 is provided with a reinforcing member 29 for linearly fixing the end portion thereof.

Further, as shown in FIG. 7, the pigtail 31
One of the two ends of the brush tail 16 may be fixed to the brush side surface 16c, or both ends of the pigtail 33 may be fixed to both side surfaces 16c of the brush 16 as shown in FIG. Incidentally, as shown in FIG. 7, in the brush holder 32 for fixing the end portion of the pigtail 31 to the brush upper surface 16a and the side surface 16c, the upper surface and the side surface on the fixing portion side are notched, and the pigtail 31 is not brushed. It is taken out from the cutout portion of the holder 32. Further, as shown in FIG. 8, in the brush holder 34 when both ends of the pigtail 33 are fixed to the brush side surface 16c, the upper surface and both side surfaces thereof are cut out, and the pigtail 33 is removed from the cutout portion of the brush holder 34. Taken out.

5 and 6, pigtails 27 and 28 are fixed symmetrically with respect to the circumferential center of the commutator 12 on the brush upper surface 16a. in this case,
The manufacturing becomes easier as compared with the case where the pigtails 31 and 33 are fixed to the brush side surface 16c (see FIGS. 7 and 8). On the other hand, as shown in FIGS. 7 and 8, when fixing the pigtails 31 and 33 to the side surface 16c of the brush, the pigtails 31 and 33 are fixed with a large width in the circumferential direction of the commutator 12, which further reduces brush vibration. It can be effectively suppressed.

5 and 6, the fixing portions of the pigtails 27 and 28 are arranged side by side so as to be parallel to the tangent line between the brush tip surface 16b and the commutator 12, but the center of rotation of the commutator 12 (rotating shaft 9). ) May be provided on a concentric circle. Even in this case, the brush vibration can be effectively suppressed.

In the above embodiment, the brush device 7 in which four (2 pairs) brushes 16 are brought into sliding contact with the commutator 12 is embodied. However, the present invention is not limited to this.
It may be embodied as a brush device in which two (one pair) brushes 16 are brought into sliding contact with the commutator 12.

The technical ideas that can be understood from the above embodiment will be described below along with their effects. (A) A brush having a substantially rectangular parallelepiped shape, the tip of which is in sliding contact with the outer peripheral surface of a substantially cylindrical commutator, a brush holder for housing and holding the brush, and a spring for urging the brush toward the commutator. A brush device including a power supply lead wire for supplying a motor drive current to the brush, wherein the power supply lead wire is provided in a plurality in a tangential direction between the brush front end surface and the commutator at a brush rear end side. Brush device characterized by being fixed in place.
By fixing the power supply lead wire to the brush in this manner, brush vibration can be suppressed, and noise due to the brush vibration can be suppressed.

[0032]

As described in detail above, according to the present invention,
Brush vibration can be suppressed and noise can be suppressed.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of a DC motor according to this embodiment.

FIG. 2 is a sectional view of a main part taken along the line AA of FIG.

FIG. 3 is a perspective view of a brush for explaining a fixing portion of a pigtail.

FIG. 4 is an explanatory diagram for explaining brush vibration.

FIG. 5 is a perspective view of a brush for explaining a fixing portion of a pigtail according to another embodiment.

FIG. 6 is a perspective view of a brush for explaining a fixing portion of a pigtail according to another embodiment.

FIG. 7 is a perspective view of a brush and a brush holder for explaining a fixing portion of a pigtail according to another embodiment.

FIG. 8 is a perspective view of a brush and a brush holder for explaining a fixing portion of a pigtail according to another embodiment.

FIG. 9 is a partial cross-sectional view showing a conventional brush device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... DC motor, 7 ... Brush device, 12 ... Commutator, 16 ... Brush, 16a ... Brush upper surface, 16c ... Brush side surface, 17 ... Coil spring, 18 ... Brush holder, 26 ... Pigtail as a power supply lead wire, 27
... a pigtail as a power supply lead wire, 28 ... a pigtail as a power supply lead wire, 31 ... a pigtail as a power supply lead wire, 32 ... a brush holder, 33 ... a pigtail as a power supply lead wire, 34 ... a brush holder.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeshi Tanaka             Asumo Corporation, 390 Umeda, Kosai City, Shizuoka Prefecture             In the company (72) Inventor Moriya Kazuma             Asumo Corporation, 390 Umeda, Kosai City, Shizuoka Prefecture             In the company F-term (reference) 5H605 AA05 CC06 CC07 DD21 EA08                       EC04                 5H613 BB15 BB27 GA17 KK03 SS06

Claims (4)

[Claims] 1. A brush having a substantially rectangular parallelepiped shape, the tip of which is in sliding contact with the outer peripheral surface of a substantially cylindrical commutator, a brush holder for accommodating and holding the brush, and a biasing force of the brush toward the commutator. A brush device including a spring and a power supply lead wire for supplying a drive current of a motor to the brush, wherein the power supply lead wire is fixed to the brush with a width in a circumferential direction rather than a radial direction of the commutator. A brush device characterized in that 2. The brush device according to claim 1, wherein the power supply lead wire is fixed symmetrically with respect to a circumferential center of the commutator on the upper surface of the brush in the axial direction of the commutator. A brush device characterized in that 3. The brush device according to claim 2, wherein the power supply lead wire is provided at two positions symmetrical with respect to the circumferential center near the circumferential end of the commutator on the upper surface of the brush. Brush device characterized by being fixed by. 4. The brush device according to claim 1, wherein the power supply lead wire is fixed at a plurality of positions of the brush, and at least one of the power supply lead wires is fixed in a circumferential direction of the commutator. A brush device characterized by being made on the side of a certain brush.