JP2606362B2 - Motor brush - Google Patents

Description

The present invention relates to a brush of a DC motor.

(Prior Art) In general, a rotor of a DC motor is configured by an electric iron core, an armature winding, a commutator, and the like. Of these, the commutator has a wedge-shaped cross section of commutator pieces and a thin mica plate alternately arranged to insulate the commutator pieces adjacent to each other, and arranges these commutator pieces and the mica plate in a cylindrical shape. I have.
One end of each commutator piece is connected to the lead wire of the coil via a riser.

The brush that elastically contacts the commutator and supplies current,
The commutator is held by the brush holder so as to be movable in the radial direction, and is pressed against the commutator surface with an appropriate pressure by the elastic force of the brush spring, and has an appropriate contact resistance to improve commutation.

In the DC motor having the radial brush holder, a plate-shaped brush that abuts the outer periphery of the commutator in the axial direction was cut in half in the brush thickness direction, and a pigtail was attached to each of the divided thin plate-shaped brushes. Things are known.

(Problems to be Solved by the Invention) However, according to such a conventional split-type thin plate brush of the DC motor, the thickness of the thin plate brush decreases as the size of the motor decreases, so that each of the thin plate brushes is reduced. However, when the pigtail mounting hole is opened, the brush may be chipped, or when the pigtail is mounted, the brush may be broken by caulking or the like, so that it is difficult to divide or thin the brush.

The present invention provides a brush that can obtain the original effective commutation characteristics of a divided brush by using a thin plate-shaped divided brush that is unlikely to cause breakage, breakage, and the like of the brush when the pigtail mounting hole is drilled and the pigtail is mounted. The purpose is to provide.

(Means for Solving the Problems) A brush for an electric motor according to the present invention for solving the above-mentioned problems has a commutator that is rotatable and a thin plate shape whose longitudinal end face abuts the outer periphery of the commutator in the axial direction thereof. A brush, a plurality of thin plate-like brushes that are overlapped so as to be dividable in the plate thickness direction, and a brush holder that holds these stacked thin plate-shaped brushes movably in the radial direction of the commutator,
A brush spring that urges the thin-plate brush in a radially inward direction of the commutator to press and contact the longitudinal end face of the thin-plate brush with the commutator, and an end face opposite to the longitudinal end face of the thin-plate brush. And a pigtail connected to an end face having a large thickness in the plate thickness direction.

(Operation) According to the motor brush of the present invention, the plurality of thin-plate brushes divided in the front and rear directions of the commutator in the rotational direction absorb the floating of the brush caused by the eccentricity and unevenness of the commutator. In addition, the rectifying action is performed favorably. In addition, since the pigtail is attached to the end face of the thin brush having the thick width, the pigtail mounting hole is formed on the end face that is relatively thick when drilling the hole of the thin brush, so that the brush chip Cracks are less likely to occur. Also, the pigtail mounting holes of the brush are less likely to break or break the brush when the pigtail is fixed by swaging.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

1 and 2 show a first embodiment to which the brush for an electric motor of the present invention is applied.

As shown in FIG. 1, the commutator 1 has a wedge-shaped conductive commutator piece 2 and an insulating thin mica plate which are alternately arranged so that adjacent commutator pieces 2 are insulated. They are arranged in a cylindrical shape. FIG. 1 shows a portion of a commutator piece 2 arranged in a cylindrical shape, which comes into contact with a brush 4.

The brush 4 that contacts the commutator 1 is composed of two thin brushes
The end faces 6a, 7a are in contact with the outer periphery of the commutator 1 along the axial direction thereof.

As shown in FIG. 2, the end face 6a of the thin brush 6 has a longitudinal surface extending in the axial direction of the commutator, and the thickness direction of the end surface 6a is a concave surface forming a part of a circular arc around the commutator. .

On the end face 6b opposite to the end face 6a, a thick portion 8 is provided in the plate thickness direction from the intermediate portion to the end portion. The thick portion 8 has a tapered surface 8a at a corner of the top surface 8c, and a pigtail mounting hole for inserting a pigtail 10 into the tapered surface 8a.
12 are open. A pin mounting hole 13 for fixing the tip of the pigtail 10 inserted into the pigtail mounting hole 12 is opened in the thickness direction on the side surface 8b of the thick portion 8.

As shown in FIG. 1, the bottom face 8e of the thick portion 8 is configured such that a gap between the bottom face 8e and the end face 7b of the other thin brush 7 is separated by a distance δ shown in the figure. This is because the commutator 1
This is to prevent the lifting caused by the vertical movement of the brush 6 or 7 caused by the eccentricity of the brush or the unevenness of the commutator surface, by the gap δ, thereby preventing the commutation from deteriorating due to the generation of a spark at the end face 6a or 7a.

Then, a concave brush spring sliding surface 14 is formed flat inside the top surface 8c connected to the tapered surface 8a via the step portion 15. The brush spring sliding surface edge 14a extending in a direction orthogonal to the commutator axial direction is in contact with the brush sliding edge 20a of the other thin brush 7. Brush spring sliding surface 1
4 and 20, the thin plate-shaped brushes 6 and 7 extend in the radial direction of the commutator 1.
Is pressed and contacted.

The other ends of the pigtails 10, 26, one ends of which are connected to the pigtail mounting holes 12, 25 of the tapered surfaces 8a, 24a of the thin brushes 6, 7, are fixed together by a flat plate 28.

The configuration of the laminar brush 7 superimposed on the laminar brush 6 is basically the same as the configuration of the laminar brush 6, and these laminar brushes 6, 7 are attached to the commutator 1 by a brush holder (not shown). It is stored movably in the radial direction,
The brush spring 22 urges the commutator 1 radially inward, and the end faces 6a and 7a are pressed against the outer peripheral surface of the commutator 1 with an appropriate contact resistance.

According to such a configuration, the brush spring sliding surfaces 14 and 22 where the brush spring 22 abuts are configured so as to be divided into two in the axial direction. Since the urging force in the direction is distributed to the two thin brushes 6 and 7 and acts evenly, the contact resistance between the end faces 6a and 7a of the thin brushes 6 and 7 and the commutator 1 is good. Become. Also, brush spring sliding surfaces 14, 20
Is divided into two parts in the axial direction, so that there is an effect that the structure is simplified such that the plate at this part can be eliminated.

Furthermore, the pigtails 10 and 26 are attached to the thin plate-shaped brush 6,
7 is performed on the thick portions 8 and 24 in the thickness direction, so that the tapered surfaces 8a and 24a at the corners can have a large thickness. Processing is facilitated, the brush is less likely to be damaged or broken, and the brush is less likely to be broken due to caulking or the like when the pigtail is attached.

FIG. 3 shows a motor brush according to a second embodiment of the present invention. These thin brushes 30 and 32 are
a and 32a are right-angled triangles, and extend in the shape of a triangular prism in a radially outward direction with respect to the commutator, and surfaces that extend up and down with the hypotenuse of the right-angled triangle as one side are overlapped. Top surface 30b, 3
A brush spring (not shown) is pressed downward on the diagonal line 34 of FIG. 2b in FIG. Pigtail mounting holes 36 and 38 are opened near the axial ends of the top surfaces 30b and 32b, and pigtails 10 and 26 are connected to the pigtail mounting holes 36 and 38, respectively, and the other ends of the pigtails 10 and 26 are provided. Although not shown, they are fixed together by a plate 28 as shown in FIG.

In the second embodiment, the thin plate-like brushes 30 and 32 are configured to be divided on a diagonal line of a rectangle having two sides in the axial direction and the circumferential direction of the commutator. In such a configuration, the top surface
Since the pigtail mounting holes 36 and 38 are opened on the thicker side of the 30b and 32b, the brush is less likely to be broken due to chipping of the brush at the time of drilling or caulking at the time of mounting the pigtail.

In the above-described embodiment, the pigtail is attached to the brush by swaging.However, in the present invention, the pigtail attachment fixing means is not limited.For example, even when the pigtail is fixed to the brush with copper powder or the like. Needless to say, the present invention can be applied.

(Effects of the Invention) As described above, according to the electric motor brush of the present invention, since the split-type thin plate-shaped brush has a thick-walled portion, when the pigtail mounting hole is machined in the brush, the brush chip is not formed. In addition to avoiding the occurrence of cracks, the breakage of the brush due to caulking when attaching the pigtail to the brush is also avoided, and the eccentricity or unevenness of the armature is caused by a plurality of thin brushes divided in the front and rear direction of rotation. There is an effect that the floating of the brush can be absorbed and the rectification can be prevented from being deteriorated due to the generation of the spark.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a motor brush according to an embodiment of the present invention, FIG. 2 is a perspective view showing the brush and a pigtail, and FIG. 3 is a motor brush according to a second embodiment of the present invention. It is a schematic perspective view. 1 commutator, 4 brush, 6, 7 thin brush, 6a, 7a end face (longitudinal end face), 8, 24 thick part, 8a, 24a taper face, 10 , 26… pigtail, 12, 25… pigtail mounting hole, 14, 20… brush spring sliding surface, 22… brush spring.

Claims (1)

(57) [Claims] 1. A commutator that is rotatable, and a thin plate-shaped brush whose longitudinal end face abuts against the outer periphery of the commutator, and a plurality of thin plates that are overlapped so as to be dividable in the plate thickness direction. A brush holder for holding the superposed thin brushes movably in the radial direction of the commutator; and urging the thin brushes in the radial direction of the commutator to apply the thin plate shape to the commutator. A brush spring that presses and contacts the longitudinal end face of the brush, and a pigtail that is connected to an end face opposite to the longitudinal end face of the thin plate-shaped brush and having a thick width in the plate thickness direction. A brush for an electric motor, characterized in that: