JP3391365B2 - DC motor brush device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC motor having a brush, and more particularly to a brush device for the DC motor.

[0002]

2. Description of the Related Art A DC motor having a brush and supplying electric power from the brush to a drive coil of a rotor core to rotate a rotary shaft is shown in FIG. In FIG. 6, in the central portion of the circular bottom plate 33, a convex portion 3
3a is formed, and the bottom plate 3 is formed by the protrusion 33a.
A concave portion 33b is formed on the upper surface side of 3. A thrust washer 35 is provided on the bottom surface of the recess 33b. Recess 3
An annular metal bearing 34 'is press-fitted and fixed to the inner peripheral surface of 3b.

On the other hand, the open end of the motor case 32 is attached to the outer edge of the bottom plate 33. Motor case 32
Is formed in a cylindrical shape with a bottom and is arranged upside down so that the bottom portion faces upward, and the outer edge portion of the bottom plate 33 is fitted and attached to the lower opening side tip portion. Also,
The drive magnet 4 is provided on the inner surface of the peripheral wall of the motor case 32.
3 is attached. Further, a cylindrical boss portion 32a protruding upward is provided in the central portion of the ceiling portion of the motor case 32. An annular bearing 34 is press-fitted and fixed to the inner peripheral surface of the boss portion 32a.

Bearing 3 mounted on motor case 32
4 and the bearing 34 'attached to the bottom plate 33 each have a hole in the center, and the rotary shaft 31 is inserted through the center hole of the bearings 34, 34'. The tip of the lower side of the rotary shaft 31 inserted through the bearings 34, 34 'is the thrust washer 3
The rotary shaft 31 is supported in the thrust direction by a thrust washer 35. Further, the rotating shaft 31 is supported in the radial direction by the bearings 34, 34 '. Therefore, the rotary shaft 31 is rotatable with respect to the motor case 32 and the bottom plate 33 by the thrust washer 35 and the bearings 34, 34 '.

A core insulator 38 is attached to an upper portion of the rotating shaft 31 inside the motor case 32.
A rotor core 39 is attached to the core insulator 38. The rotor core 39 is configured by laminating a plurality of magnetic plates of the same shape, has a plurality of salient poles on the outer periphery, and
A coil 37 is wound around each salient pole. The salient poles of the rotor core 39 face the inner peripheral surface of the drive magnet 43 mounted on the inner surface of the peripheral wall of the motor case 32 with a certain gap.

A commutator 44 is attached to the outer peripheral surface of the rotary shaft 31 below the core insulator 38. Commutator 44
Is mainly composed of a commutator holder 40, a commutator segment 42, an arc extinguishing element 36, an oil washer 41, and the like. Of these, a commutator holder 40 is attached to the rotary shaft 31. A plurality of commutator segments 42 are attached to the outer circumferential surface of the commutator holder 40 in the circumferential direction with a certain gap therebetween. One end of each commutator segment 42 is a riser portion 42a that is pulled out axially upward and is bent outward.
One end of the coil 37 wound around the salient pole of the rotor core 39 is wound around and electrically connected to the riser portion 42a. Further, the arc extinguishing element 36 is attached to the outer peripheral side of the commutator holder 40, which is provided with a plurality of commutator segments 42. The upper surface of the arc extinguishing element 36 is in contact with the lower surface of the riser portion 42a.

On the other hand, two power supply terminals 60, 60 are provided on a portion of the bottom plate 33 outside the recess 33b. The power supply terminal 60 includes a brush terminal 52, a brush 51, and the like. As shown in FIG. 7B, the brush 51 has a fixed portion 51a at one end in the longitudinal direction,
The fixing portion 51a is fixed to the brush terminal 52 by a method such as caulking or spot welding. Also,
The other end of the brush 51 is provided with two slits in the longitudinal direction of the brush 51, and three slits 51b are formed by the slits. Each brush piece 51b is provided with a concave portion on the tip end side, and a clad 54 made of a noble metal is embedded in the concave portion. As shown in FIG. 7A, the clad 54 is in sliding contact with one of the plurality of commutator segments 42 provided on the outer peripheral surface of the commutator holder 40. Brushes 51 provided on the power supply terminals 60, 60,
The tip portion of 51 is in sliding contact with different commutator segments 42 located at mutually opposite positions with the rotary shaft 31 interposed therebetween. Furthermore, on the surface of the brush 51 on the side opposite to the clad 54 and at the base of the three brush pieces 51b,
In order to suppress vibration of the brush 51, a vibration prevention member 55 made of resin or synthetic rubber is provided.

The brush terminal 52 has a connection portion (not shown) protruding from the inside of the motor case 32 to the outside. A lead wire or the like connected to an external power source is connected to a connection portion (not shown) protruding to the outside of the motor case 32. Such power supply terminals 60, 60 are used for the motor case 3
2 and the bottom plate 33 are electrically insulated.

In FIG. 6, when a lead wire is connected to a connecting portion (not shown) of the brush terminal 52 to supply power from an external power source, the power source supplies the coil 37 through the brush terminal 52, the brush 51, the commutator segment 42 and the like. Is supplied to. By supplying power to the coil 37,
The rotor core 39, in which the coil 37 is wound around the salient poles, is circumferentially driven by the electromagnetic force between the rotor core 39 and the opposing drive magnet 43 with a certain gap. When the rotor core 39 is driven in the circumferential direction, the rotary shaft 31 integrated with the rotor core 39 also rotates in the circumferential direction, whereby the commutator segment 42 with which the brush 51 slides is sequentially switched to the next segment, and as a result, The rotor core 39 and the rotary shaft 31 are continuously driven to rotate.

[0010]

In the DC motor having the above brush device, the vibration preventing member 5 made of resin or synthetic rubber is used for the brush 51 in order to prevent vibration of the brush 51.
5 is attached by adhesion or the like. However, the adhesive used to attach the vibration prevention member 55 is
In some cases, a conduction failure occurred in the clad 54 formed at one end of the No. 1 in the longitudinal direction. Therefore, in order to eliminate such a problem, the vibration preventing member 55 is provided in the cladding 5.
Brush piece 51 which is a fulcrum side of the brush 51 separated from
It was attached to the base of b.

Further, as the DC motor is rotationally driven, the clad 54 of the brush 51 sliding on the commutator segment 42a of the commutator 44 is worn away. As the wear progresses, as shown in FIG. 8A, the thickness of the brush 51 becomes
When the thickness is 50% or less of the original plate thickness, as shown in FIG. 8 (b), the worn portion causes the brush 51 to sag. As a result, the brush 51 is wound around the commutator 44, and the like.
It causes the shortening of the motor life.

FIG. 9 shows the relationship between the brush wear amount and the motor life time. In FIG. 9, the brush wear of the motor significantly progresses at the beginning of use due to initial running-in wear. However, when a certain amount of wear occurs, it becomes steady wear and the amount of wear per certain time decreases. However, if you continue to use the motor and the amount of brush wear exceeds 50%,
(1) Acceleration of wear due to brush settling, (2) Stoppage due to winding of the brush 51 around the commutator, etc. occur, at which point the life of the motor ends. Even if the wear amount of the brush 51 exceeds 50%, (1) wear promotion due to brush brushing, (2) stop due to winding of the brush 51 around the commutator, etc. are eliminated, and as shown by a dotted line A, I want to extend the life time of the motor until 51 is completely worn, but there was no concrete method.

The present invention has been made in order to solve the above problems of the prior art, and an object of the present invention is to provide a brush device for a DC motor capable of extending the life of the motor.

[0014]

[0015]

The invention according to claim 1 is
A brush device for a DC motor, comprising a brush made of a conductive elastic material, a vibration-preventing member attached to the brush, and a commutator that makes sliding contact with the brush, the surface being opposite to the side in sliding contact with the commutator of the brush. An anti-vibration member is attached by molding to the anti-vibration member, and the anti-vibration member has a protrusion that penetrates the brush and protrudes on both sides in the longitudinal direction with a contact point of the brush with the commutator being interposed. It is characterized by

[0016]

[0017] According to a second aspect of the invention, characterized in that the noble metal member is provided near the contact point between the brush commutator.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A brush device for a DC motor according to the present invention will be described below with reference to the drawings. Since the basic configuration of the DC motor is the same as that of the conventional example described above, the description thereof is omitted here, and only the brush device will be mainly described. In FIG. 1, a bearing 21 is provided at the center of the bottom plate 10, and the bearing 21 has a rotating shaft 3
Is inserted, and the rotating shaft 3 is rotatably supported by a bearing 21. A commutator 5 is provided on the outer peripheral surface of the rotating shaft 3. The outer peripheral surface of the commutator 5 is evenly divided by three slits, and a commutator segment 5a is arranged in each of the divided portions. One end of a coil (not shown) is electrically connected to each commutator segment 5a.

Further, in FIG. 1 (a), on the bottom plate 10, the power supply terminals 2 are provided on both sides in the horizontal direction about the rotation shaft 3.
0 and 20 are provided. Each power supply terminal 20 is composed of the brush terminal 4, the brush 1, and the like. The brush terminal 4 includes a fixing portion 4a and a lead connecting portion 4 that penetrates the bottom plate 10 from the brush terminal 4 and projects to the back surface side.
b etc. The brush 1 has a fixing portion 1a at one end in the longitudinal direction.
Is provided, and the fixing portion 1 a is fixed to the brush terminal 4. Further, the other end of the brush 1 on the side opposite to the fixed portion 1a in the longitudinal direction extends toward the rotary shaft 3 side.

Two slits are provided in the longitudinal direction at the other end of the brush 1 on the side opposite to the fixed portion 1a in the longitudinal direction, and these two slits form three brush pieces 1
b, 1b, and 1b have occurred. A concave portion is provided on the tip side of each brush piece 1b and on the surface on the rotating shaft 3 side, and a clad 6 made of a noble metal is embedded in the concave portion. The clad 6 has a contact point with the commutator 5 and is in sliding contact with a commutator segment 5 a provided on the outer peripheral surface of the commutator 5.

Further, on the surface of the brush 1 opposite to the clad 6, the back surface of the clad 6 is covered from the tip of the brush piece 1b to the portion where the brush piece 1b on the fixed portion 1a side is formed. Vibration preventing members 2 made of resin, synthetic rubber, or the like are attached continuously, that is, on both sides in the longitudinal direction of the back surface portion of the contact point with the commutator 5 of the brush piece 1b. The vibration preventing member 2 is fixed by interposing an adhesive between the vibration preventing member 2 and the brush 1 which is the object of fixing. However, in order to prevent the adhesive from adhering to the clad 6 and causing a conduction failure, the back surface of the clad 6 of the brush 1 has a non-adhesive portion 2 to which no adhesive is applied.
a, and an adhesive agent is interposed in a portion excluding the non-adhesive portion 2a.

According to the brush device for the DC motor having the above-described structure, the vibration preventing member 2 is continuously provided on the surface of the brush 1 opposite to the side in sliding contact with the commutator 5 so as to cover the back surface of the clad 6. Is provided, and since an adhesive is interposed between the vibration prevention member 2 and the brush 1 except for the back surface portion of the clad 6, the clad 6 that is a contact point with the commutator 5 of the brush 1 is provided. Even if the abrasion of the portion progresses and the abrasion amount of the brush 1 progresses by 50% or more, the worn portion is reinforced by the vibration preventing member 2 fixed by an adhesive except for the back surface portion of the clad 6, and the brush 1 has a setback. Never. Therefore, the wear of the brush is not accelerated by the settling, the brush 1 is not caught in the commutator 5, and the DC motor can be used until the brush 1 is completely worn and cut. Therefore, the life of the motor can be extended to about twice that of the conventional one. Also, the vibration prevention member 2
Since the back surface portion of the clad 6 is a non-bonded portion 2a to which no adhesive is applied, the adhesive used for fixing the vibration preventing member 2 reaches the clad 6 portion of the brush 1 to prevent defective conduction. It can be eliminated.

The brush pieces 1b, 1 of the brush 1 are
Although b and 1b are integrated by the vibration prevention member 2, a slit is formed in a portion of the vibration prevention member 2 that overlaps with the slit of the brush 1, and each brush piece 1b, 1b, 1b.
It may be configured such that b can swing independently.

Further, in the above embodiment, the vibration prevention member 2
Was adhered and fixed to the brush 1. However, as shown in FIG. 2, the vibration preventing member 22 may be attached to the brush 1 by outsert molding resin or synthetic rubber without using an adhesive. In FIG. 2, the surface of the brush 1 opposite to the clad 6 is almost entirely covered with the vibration preventing member 22, and a part of the vibration preventing member 22 is clad from the slit formed in the brush 1. 6
The protrusions 22b, 22b ', and 22c project to the side. Of these, the protrusions 22b and 22b 'are the cladding 6
Are provided on both sides in the longitudinal direction and cover the surface of the brush 1 on the clad 6 side in a direction orthogonal to the longitudinal direction. The protrusion 22c is provided at the base of the brush piece 1b and covers the surface of the brush 1 on the clad 6 side in a direction orthogonal to the longitudinal direction, like the protrusions 22b and 22b '. By virtue of the protrusions 22b, 22b ', 22c covering the surface of the brush 1 on the clad 6 side, the vibration preventing member 22 is firmly fixed without being separated from the brush 1.

By forming the vibration preventing member 22 by outsert molding as described above, since no adhesive is used, the clad 6 does not cause conduction failure. Further, since the brush 1 is reinforced by the vibration preventing member 22, the brush 1 can be used until it is completely cut due to wear, and the life of the DC motor can be extended.

Further, when the vibration preventing member 22 is formed by outsert molding, a part of the vibration preventing member 22 is projected from the slit provided in the brush 1 to the surface on the clad 6 side, but this is not the only option. Not a thing. As shown in FIGS. 3 and 4, a plurality of holes 1g, 1h, 1i are formed in each brush piece 1b at arbitrary intervals in the longitudinal direction of each brush piece 1b, and the clad 6 of the brush 1 is formed from the holes.
The protrusion 22 for protruding a part of the vibration prevention member 22 on the side surface and fixing the vibration prevention member 22 so as not to come off.
b, 22b', it may form a 2 2c. By doing so, since the vibration preventing member 22 into the slit of the brush 1 can not reach, each brush piece 1b can swing independently.

Next, another embodiment of the brush device for the DC motor will be described. In FIG. 5 (a),
Each of the brush pieces 1b of the brush 1 is provided with a convex portion 1d over the entire lateral direction by bending molding or the like, and the convex portion 1d forms a concave portion 1c on the back surface side of the brush piece 1b. There is. A clad 6 having a contact point with a commutator (not shown) is provided on the surface of the convex portion 1d .
Also, on the surface of the brush 1 opposite to the clad 6, and
A continuous vibration preventing member 2 is adhesively fixed from the tip of the brush piece 1b to the base of the brush piece 1b. The entire surface of the vibration preventing member 2 on the brush piece 1b side is previously coated with an adhesive, but a space is created by the recess 1c in the portion of the brush piece 1b on the back surface side of the clad 6, The portion of the vibration preventing member 2 corresponding to the portion of the recess 1c is a non-contact portion with the brush piece 1b (brush 1).

According to the brush device for the DC motor having the above-described structure, the vibration preventing member is formed on the surface of the brush 1 opposite to the side in sliding contact with the commutator (not shown) so as to cover the back surface of the clad 6. Since 2 is bonded and fixed, the wear of the clad 6 portion, which is the contact point with the commutator 5 of the brush 1, progresses, and even if the wear amount of the brush 1 progresses by 50% or more, the worn portion is the back surface portion of the clad 6. With the exception of the above, the brush 1 is reinforced by the vibration-preventing member 2 fixed with an adhesive, and the brush 1 is prevented from being settled. Therefore, the wear due to the settling is not promoted, and the brush 1 is not caught in the commutator 5. Therefore, the DC motor can be used until the brush 1 is completely worn and cut, and the life of the motor is extended. can do. Further, since the non-contact portion between the brush 1 and the vibration preventing member 2 caused by the concave portion 1c of each brush piece 1b can prevent the adhesive agent from reaching the clad 6, the adhesive agent clad 6 of the brush 1 can be prevented. It is possible to eliminate the occurrence of defective conduction extending to the portion. Further, even in the conventional brush structure in which the vibration preventing member is fixedly adhered to the back surface of the clad, the concave portion is formed from the side opposite to the clad of the brush piece to prevent the adhesive from reaching the clad. Therefore, it is possible to construct a structure that is inexpensive in terms of construction and easy to manufacture.

In the above embodiment, the convex portion 1d is formed on the brush piece 1b of the brush 1, and the concave portion 1c formed thereby forms the non-contact portion of the vibration preventing member 2 with the brush 1. It was However, not limited to this, FIG.
As shown in FIG. 3, a protrusion 2d is formed toward the vibration preventing member 2, and the clad 6 is formed by the recess 2e formed by the protrusion 2d.
It is also possible to provide a non-contact portion of the vibration preventing member 2 with the brush 1 on the back side of the. It is possible to prevent the adhesive from reaching the clad 6 by the non-contact portion and eliminate the occurrence of poor conduction. Further, the brush 1 is a vibration prevention member 2
Since it is reinforced by, the wear of 50% or more does not cause fatigue and the life of the DC motor can be extended.
In this case, as the material used for the vibration prevention member 2,
A rubber material having rigidity is preferable.

Next, another embodiment of the brush device for the DC motor will be described. In FIG. 5 (b),
A convex portion 1f is provided at the tip of each brush piece 1b of the brush 1. The convex portion 1f is formed not only in the entire lateral direction of the brush piece 1b but only in the central portion by punching or the like. Therefore, the convex portion 1f has a form surrounded by a flat portion. The convex portion 1f is provided with a clad 6 having a contact point with a commutator (not shown). Further, a continuous vibration preventing member 2 is adhesively fixed on the surface of the brush 1 opposite to the clad 6 and from the tip of the brush piece 1b to the base of the brush piece 1b. In the portion of the brush piece 1b on the back surface side of the clad 6, a concave portion is formed by the convex portion 1f. A portion of the vibration prevention member 2 corresponding to the concave portion generated by the convex portion 1f is a non-contact portion with the brush piece 1b.

According to the brush device for a DC motor having the above-described structure, since the convex portion 1f of the brush piece 1b to which the clad 6 is attached has a flat portion around it.
Even if the protrusion 1f that slides on a not-shown commutator is worn away, the protrusion 1f is held by the flat portion of the brush piece 1b located on the outer periphery. Therefore, even if the amount of wear advances by 50% or more, the brush 1 (brush piece 1b)
The life of the DC motor can be extended without sagging.

[0032]

[0033]

According to the invention as set forth in claim 1 , a vibration preventing member is molded on the surface of the brush opposite to the side in sliding contact with the commutator, and the vibration preventing member penetrates the brush. Moreover, since the vibration preventing member has protrusions protruding on both sides in the longitudinal direction of the contact point of the brush with the commutator, the vibration preventing member can be fixed to the brush without using an adhesive, and the adhesive can be applied to the brush. it can be eliminated that a conduction failure occurs span of the contact point with the commutator. Further, even if the brush is worn out, the brush is reinforced by the vibration-preventing member, so that the brush does not suffer from settling and the life of the DC motor can be extended.

[0034]

[Brief description of drawings]

1 shows an embodiment of a brush device for a DC motor according to the present invention, (a) is a plan view, (b) is a side view,
(C) is an enlarged side view of the main part.

FIG. 2 is a diagram showing another embodiment of a brush device for a DC motor according to the present invention.

FIG. 3 is a perspective view showing yet another embodiment of a brush device for a DC motor according to the present invention.

FIG. 4 is a cross-sectional view showing an enlarged main part of the same.

FIG. 5 is a diagram showing another embodiment of a brush device for a DC motor according to the present invention.

FIG. 6 is a sectional view showing an example of a conventional brush device for a DC motor.

FIG. 7 shows an example of a brush device for a DC motor,
(A) is a plan view and (b) is a side view.

FIG. 8 is an enlarged view of a main portion showing an example of a conventional brush device of a DC motor and a set.

FIG. 9 is a graph showing the relationship between brush wear and motor life.

[Explanation of symbols]

1 brush 2 Vibration prevention member 5 commutator

Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 13/00-13/14 H01R 39/00-39/64

Claims (2)

(57) [Claims] 1. A brush device for a DC motor, comprising: a brush made of a conductive elastic material; a vibration-preventing member attached to the brush; and a commutator slidably contacting with the brush. and is the vibration preventing member on the opposite side kicked Installing by molding the sliding contact side and, the vibration preventing member extends through the brush, and the
On both sides in the longitudinal direction across the contact point of the brush with the above commutator
A brush device for a DC motor, which has a protruding portion . 2. A vicinity of a contact point of the brush with the commutator
The precious metal material is provided in the
1. A brush device for a DC motor according to 1 .