JPH1118374A - Brush device for motor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brush device, for a motor, which can be worked simply and to provide a manufacturing method, of the brush device for the motor, in which the molding man-hours of a carbon brush is reduced. SOLUTION: An inclined coil-spring contact face is formed on the other end face of a shaft-shaped brush 40 one end face 40a of which is pushed to the circumferential face Sa of a commutator S. A flat face 41 which is at right angles to the axial line of the brush 40 is formed partly on the coil-spring contact face. The connection hole 42 of a power-supply member 60 is opened in the flat face 41. In addition, when the shaft-shaped brush 40 which is pressed to the circumferential face Sa of the commutator S is molded of a brush material so as to be worked, the inclined coil-spring contact face and the flat face 41 which is at right angles to the axial line are molded on the other end of the brush 40, and, after that, the connection hole 42, of the power-supply member 60, which is extended in the axial direction of the brush 40 and which is opened in the inclined coil-spring contact face 40b is formed.

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 an electric motor, in which a connection hole for connecting a pig-tilt is formed on a coil spring contact surface of a brush, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, there has been known a brush device of a motor for supplying power to a commutator such as a commutator motor.

[0003] As shown in Fig. 4, for example, this brush device includes a brush holder 1 mounted on a case body of an electric motor.
The brush guide 2 includes a cylindrical brush guide 2 fitted inside the brush guide 2 and facing the peripheral surface Sa of the commutator S, and a brush body 3 fitted and supported in the brush guide 2.

The brush body 3 includes a carbon brush 4
The coil spring 5 for pressing the brush surface 4a of the carbon brush 4 against the peripheral surface Sa of the commutator S, the pigtail 6 having the carbon brush 4 connected to the tip 6a, and the rear end 6b of the pigtil 6 are connected. It consists of a brush cap 7. The coil spring 5 is a carbon brush 4
And the brush cap 7.

[0005] As shown in FIG.
The brush surface 4a slidingly contacting the circumferential surface Sa of the commutator S and the length A of the one side surface 4c located on the rear side in the rotation direction R of the commutator S are located on the front side in the rotation direction R of the commutator S. Side 4d
And a coil spring contact surface 4b in the form of an inclined surface having a reduced length B. The coil spring contact surface 4b is formed with a connection hole H to which the tip 6a of the pig tail 6 is connected.

In the brush device constructed as above, the point of action J of the urging force of the coil spring 5 urging the coil spring contact surface 4b of the carbon brush 4 and the fulcrum K of the carbon brush 4 are perpendicular to the axis of the carbon brush 4. Since it is displaced in the direction, a rotational moment M having a length of a straight line connecting the two points J and K acts on the carbon brush 4 to apply a clockwise force to the carbon brush 4. As a result, one side surface 4d of the carbon brush 4 is pressed against the brush guide side wall 2a behind the commutator S in the rotation direction R of the brush guide 2.

When the commutator S is rotated in this state, the brush surface 4a of the carbon brush 4 is slid in the rotational direction R of the commutator S due to frictional resistance with the peripheral surface Sa of the commutator S, and the rotational moment M Is the same as the direction of the force exerted on the brush surface 4a of the carbon brush 4, so that the rotation of the commutator S according to the change in the frictional resistance between the circumferential surface Sa of the commutator S and the brush surface 4a of the carbon brush 4 Despite the fluctuation of the force dragged in the direction R, the state where the carbon brush 4 is stabilized by the rotational moment M is prevented from being broken. In this way, the play of the carbon brush 4 is suppressed, and the seating of the carbon brush 4 on the commutator S is improved.

When manufacturing the brush device for the electric motor, the brush main body 3 is manufactured according to the procedure shown in FIG.

In manufacturing the carbon brush 4, FIG.
, A tip 8a opposite to the brush surface (not shown) is formed into a flat surface, and the tip 8a of the carbon base 8 is cut obliquely to incline a coil spring contact surface. 4b is processed (see FIG. 6B). After machining of the coil spring contact surface 4b, a hole 9 is formed in the connection hole H of the pigtail 6 with a drill 9 on the coil spring contact surface 4b (see FIG. 6C), and the carbon brush 4 is manufactured.

After the carbon brush 4 is manufactured, the tip 6a of the pigtail 6 is inserted into the connection hole H of the coil spring contact surface 4b, and the connection hole H is formed by the injected liquid adhesive.
Of the copper powder CA packed in
a is fixedly connected to the connection hole H, and one end 5a of the coil spring 5 is attached to the coil spring contact surface 4b with the pigtail 6 inside.
(See FIG. 5).

Next, the rear end 6b of the pigtail 6 is welded to the brush cap 7 by spot welding or the like, and the other end 5b of the coil spring 5 is brought into contact with the brush cap 7.

[0012]

However, in the above-described brush device for an electric motor, when drilling the connection hole H of the pigtail 6, the coil spring contact surface 4b is inclined, so that the tip of the drill 9 tends to slide. It is difficult to drill holes.

Further, when manufacturing the carbon brush 4,
There is a problem that it takes time to cut the tip 8a of the brush base material 8 obliquely and process the coil spring contact surface 4b.

Accordingly, a first object of the present invention is to provide a brush device for an electric motor that is easy to process, and a second object is to provide a method of manufacturing a brush device for an electric motor in which the number of steps for forming a carbon brush is reduced. Is to do.

[0015]

In order to achieve the first object, a first aspect of the present invention is a coil spring contacted with one end face inclined to the other end face of a shaft-shaped brush pressed against the peripheral surface of a commutator. An electric motor having a surface formed, a connecting hole of a power supply member extending in the axial direction of the brush and opening to the coil spring contact surface formed in the brush, and a power supply member connected to the connection hole of the power supply member. In the brush device of
A flat surface orthogonal to an axis of the brush is partially formed in the coil spring contact surface, and a connection hole of the power supply member is opened in the flat surface.

According to a second aspect of the present invention, the inclined coil spring contact surface and the brush are formed when the shaft-like brush according to the first aspect is formed from brush material powder. A flat surface orthogonal to the axis of the brush is formed at the other end of the brush, and then a connection hole of a power supply member is formed which extends in the axial direction of the brush and opens at the inclined coil spring contact surface. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a brush device for an electric motor and a method of manufacturing the same according to the present invention will be described below with reference to the drawings.

[Brush Apparatus] In FIGS. 1 and 2, reference numeral 10 denotes a brush holder mounted on a case main body of an electric motor, 20 denotes a brush guide provided on the brush holder 10, 30 denotes a brush main body, and S denotes a commutator of the electric motor. It is.

The brush holder 10 has a main body 11 formed of an electrically insulating material such as a synthetic resin into a substantially rectangular tube shape.

The main body 11 has a support piece 12 integrally formed therewith. The main body 11 is attached to the mounting hole 12 of the support piece 12.
The lower surface 11a of the main body 11 is opposed to the peripheral surface Sa of the commutator S by being fixed to a case main body of an electric motor (not shown) via screws a and the like. A substantially rectangular cylindrical insertion hole 13 is formed in the main body 11 to fit a metal brush guide 20. A substantially parallel to the insertion hole 13 is provided between the insertion hole 13 and the support piece 12. Terminal mounting hole 1 formed in
4 are formed.

The brush guide 20 has a guide side wall 20a.
, A guide side wall 20b, a guide side wall 20c, and a guide side wall 20d.

The guide side walls 20a and 20b are parallel to each other, and the guide side walls 20c and 20b are parallel to each other.
“d” connects the ends of the guide side walls 20a and 20b to be parallel to each other, and bulges out the intermediate portion to the outside.

The brush guide 20 protrudes from the lower surface 11a of the main body 11 and has a tip opening 20e of the brush guide 20.
Is opposed to the peripheral surface Sa of the commutator S and is provided in the radial direction of the commutator S.

The guide side wall 20a has a rotational direction R of the commutator S.
The guide partition 20d is located on the front side, and is located on the rear side in the rotation direction R of the commutator S. In FIG. 2, the arrow R indicates the rotation direction of the commutator S.

A cut-and-raised piece 20g is formed in the middle of the brush guide 20 so as to be hooked on the lower surface 11a of the main body 11, and a stopper piece 20h is formed at the rear end of the brush guide 20 at the opening edge 13a of the insertion hole 13. The brush guide 20 is bent and fixed in the insertion hole 13 of the main body 11.

The brush body 30 includes a carbon brush 40
And a coil spring 50 for urging the carbon brush 40
, A pig till 60, and a brush cap 70.

The carbon brush 40 is a brush guide 20
It has a substantially square shaft shape inserted into the inside.

At one end of the carbon brush 40, a concave brush surface 40a which is in sliding contact with the peripheral surface Sa of the commutator S is formed, and at the other end of the carbon brush 40, a coil spring contact surface 40b which contacts a coil spring is inclined. It is formed.

Here, the length of one side surface 40c of the carbon brush 40 located on the rear side in the rotation direction R of the commutator S is L1, and the other side surface 40d of the carbon brush 40 located on the front side in the rotation direction R of the commutator S is L1. Is L2, the length L of one side surface 40c is determined by the inclined coil spring contact surface 40b.
1 is longer than the length L2 of the other side surface 40d. In addition,
The angle between the line parallel to the direction perpendicular to the axis of the carbon brush 40 and the coil spring contact surface 40b is 12 to 15 degrees.

A flat surface 41 orthogonal to the axis of the carbon brush 40 is formed on the coil spring contact surface 40b.
A connection hole 42 of a pigtail 60 is formed on the flat surface 41 so as to extend in the axial direction of the carbon brush 40, and the flat surface 4
1 is open.

The coil spring 50 is interposed between the coil spring contact surface 40b of the carbon brush 40 and the brush cap 70. The distal end 50a of the coil spring 50 is in contact with the coil spring contact surface 40b, and the rear end 50b of the coil spring 50 is in contact with the brush cap 70.

The coil spring 50 is formed of a carbon brush 4
0 is constantly urged toward the commutator S, so that the brush surface 40a of the carbon brush 40 protrudes from the tip 20e of the brush guide 20, and the brush surface 40a is slidably pressed against the peripheral surface Sa of the commutator S. ing.

The pigtail 60 (power supply member) is connected to the coil spring contact surface 40 b of the carbon brush 40 and the brush cap 70.

The tip 60 is inserted into the connection hole 42 formed in the coil spring contact surface 40b, and is cured by a liquid adhesive into which the copper powder CA filled in the connection hole 42 has been injected. Hardened copper powder C
A causes the tip 60a of the pigtil 60 to be connected to the connection hole 42.
Fixed to The rear end 60b of the pigtail 60 is spot-welded to the brush cap 70.

The brush cap 70 is made of sheet metal, and is a cap piece 7 that covers the opening 13 a of the insertion hole 13 of the main body 11.
1 and a retaining piece 72 inserted into the terminal mounting hole 14.

The rear end 50b of the coil spring 50 is in contact with the cap piece 71, and the rear end 60b of the pigtail 60 is welded. .

The retaining piece 72 is formed by a convex portion 73 curved in an arcuate cross section and an elastically deformable bent portion 74 bent in a mountain shape continuously from the convex portion 73. I have.

The tops of the convex portion 73 and the bent portion 74 are pressed against the inner surface of the terminal mounting hole 14. A projection 74 a projecting from the terminal mounting hole 14 is provided at the tip of the bent portion 74, and the projection 74 a is provided on the lower surface 11 of the main body 11.
The locking piece 75 to be hooked on a is cut and raised integrally.

The locking piece 75 sandwiches the main body 11 with the cap piece 71 to prevent the brush cap 70 from coming out of the terminal mounting hole 14.

The protruding portion 74a is inserted into a connection terminal of a terminal block attached to a stator core of a motor stator (not shown), and is connected to a stator winding via this terminal.

In the motor brush device having such a configuration, the flat surface 41 is formed on a part of the inclined coil spring contact surface 40b, and the connection hole 42 of the pigtail 60 is formed on the flat surface 41. Thus, it is possible to obtain a brush device which can be easily processed.

[Method of Manufacturing Brush Apparatus] When manufacturing the brush apparatus of the electric motor, the brush body 30 is manufactured according to the procedure shown in FIG.

First, carbon powder of the main component, which is a raw material, and a binder of a synthetic resin are compression-molded by a molding machine (not shown) and then sintered to produce a molded body 45 of the carbon brush 40.

At the time of the compression molding, the molded body 45 includes:
As shown in FIG. 3A, the brush surface 40a (not shown)
And the flat surface 41 is formed integrally at the approximate center of the inclined coil spring contact surface 40b.

After the production of the molded body 45, as shown in FIG. 3 (b), the flat hole 41 of the coil spring contact surface 40b is connected to the connection hole 4 of the pigtail 60 indicated by a broken line by a drill 80.
By performing the second hole processing, the carbon brush 40 is manufactured.
In addition, an appropriate amount of a required metal powder may be mixed in the raw material of the carbon brush 40 depending on the use.

After the carbon brush 40 is manufactured, the connection holes 4
2. Insert the tip 60a of the pig till 60 into the connection hole 4
2 is hardened by the injected liquid adhesive, and the tip 60a of the pigtail 60 is fixedly connected to the connection hole 42 by the hardened copper powder CA.

After the pigtail 60 is fixedly connected to the connection hole 42, the tip 50a of the coil spring 50 is brought into contact with the coil spring contact surface 40b so that the pigtail 60 is inside (see FIGS. 1 and 2).

Next, the cap piece 7 of the brush cap 70
1, the rear end 60b of the pigtail 60 is welded by spot welding or the like, and the other end 50b of the coil spring 50 is brought into contact with the cap piece 71.

In the method of manufacturing such a motor brush device, the molded body 45 is formed by molding the brush surface 40a and the coil spring contact surface 40b on which the flat surface 41 is formed. The labor for processing can be omitted, and the man-hour for forming the carbon brush 40 can be reduced.

Further, since the processing surface for forming the connection hole 42 of the pigtail 60 is a flat surface, the tip of the drill 80 used for the hole processing does not slip and the hole processing can be easily performed.

[0051]

As described above, according to the first aspect of the present invention, an inclined coil spring contact surface is formed on the other end surface of a shaft-like brush whose one end surface is pressed against the peripheral surface of the commutator. A connection hole for a power supply member extending in the axial direction of the brush and opening to the contact surface of the coil spring, wherein the connection hole of the power supply member is formed in the brush, and the power supply member is connected to the connection hole of the power supply member; Since a flat surface perpendicular to the axis of the brush is partially formed on the contact surface, and the connection hole of the power supply member is opened in the flat surface, a brush device that can be easily processed can be obtained.

According to a second aspect of the present invention, when the shaft-shaped brush of the first aspect is formed from brush material powder, the inclined coil spring contact surface and the flat surface orthogonal to the axis of the brush are formed. After being formed at the other end of the brush, since a connection hole of a power supply member extending in the axial direction of the brush and opening to the inclined coil spring contact surface is formed, the number of molding steps of the carbon brush can be reduced,
Drilling of the connection hole of the power supply member can be easily performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part in a state where a brush device for an electric motor according to the present invention is mounted on a peripheral surface of a commutator.

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

FIGS. 3A and 3B are diagrams for manufacturing a carbon brush, in which FIG. 3A shows a plane (coil spring contact surface) and a cross section of a carbon brush molded body, and FIG. FIG.

FIG. 4 is a cross-sectional view of a main part in a state where a conventional brush device for an electric motor is mounted on a peripheral surface of a commutator.

FIG. 5 is a sectional view taken along the line EE of FIG. 4;

FIGS. 6A and 6B are diagrams for manufacturing a carbon brush, FIG. 6A is a diagram of a carbon brush compact, FIG. 6B is a diagram of a coil spring contact surface cut and formed, and FIG. It is a figure which processes the connection hole of a pigtail in a contact surface.

[Description of Signs] 40: brush (carbon brush) 40a: one end surface (brush surface) 40b: coil spring contact surface 41: flat surface 42: connection hole 60: power supply member (pigtail)

Claims (2)

[Claims] 1. An inclined brush spring contact surface is formed on the other end surface of a shaft-like brush whose one end surface is pressed against the peripheral surface of a commutator, and extends in the axial direction of the brush and the coil spring contact surface. In the brush device of the electric motor, wherein a connection hole of a power supply member that opens to the brush is formed in the brush, and a power supply member is connected to the connection hole of the power supply member, a flat surface orthogonal to an axis of the brush is provided on the coil spring contact surface. A brush device for an electric motor, wherein the brush member is partially formed, and a connection hole of the power supply member opens in the flat surface. 2. When the shaft-shaped brush according to claim 1 is formed from brush material powder, the inclined coil spring contact surface and a flat surface orthogonal to the brush axis are formed at the other end of the brush. And forming a connection hole for a power supply member extending in the axial direction of the brush and opening to the inclined coil spring contact surface.