JPS6325895Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to improvement of motor brushes.

FIG. 1 shows an example of a conventional motor brush.
Reference numeral 1 denotes a brush body, the head of which is housed in a holder portion 02 provided on a metal brush plate 01, and the brush body 1 is attached to the brush plate 01 by pressure support from all four circumferences.

This brush has been used in small motors, but the inventors planned to use it in slightly larger motors. When they tried to make a prototype with a slightly larger overall brush shape, most of the prototypes were damaged during production.

The damage occurs in the form of a crack in the brush body 1, and the location where the crack occurs is in the holder part 0.
This is the part that comes into contact with both corner portions 03 and 04 of No. 2.

This invention aims to solve the above problem.

This idea has other secondary objectives. The motor brush is used to supply power to the rotor of the motor. Then, the bottom surface of the brush body 1 comes into contact with a rotor (not shown), and the brush plate 01 acts as a leaf spring to press the brush body 1 against the rotor to maintain contact. In this case, firstly, the contact between the brush body 1 and the rotor must be uniform, and the stress on the contact surfaces between the two must also be uniform. Second, it is necessary to be able to control the contact force between the brush body 1 and the trochanter at a constant level. This is because the lack of any of the conditions will impair the life of the brushes and rotor. A secondary purpose of this invention is to prevent damage to the brush main body 1 due to the increase in size of the brush without compromising these conditions.

In the motor brush of this invention, an inverted trapezoidal head 4 of a brush body 1 is housed in a groove-shaped holder portion 12 provided on an elastic metal brush plate 11 and having a shape that almost matches the head 4. The both sides 2 and 3 of the brush body 1 are supported by pressure by both edges of the holder part 12, and the bottom of the holder part 12 is provided to prevent sideways movement of the brush body 1 in directions other than the sides 2 and 3. In the case where small protrusions 13 and 14 are provided as means and these small protrusions 13 and 14 are brought into contact with the head 4 of the brush body 1 from a direction other than both sides 2 and 3,
Corner 15, 1 between the bottom of the holder part 12 and both edges
6, a through hole 17 is provided along the center of the holder portion 12.

In this invention, the through hole 17 provided between the corners 15 and 16 weakens the rigidity of the brush plate 11 at the corners 15 and 16, thereby preventing damage when the brush body 1 is attached.

Each embodiment of this invention will be described below.

A first embodiment of this invention is shown in FIGS. 2 and 3. In the figure, reference numeral 1 denotes a brush body, which is made of a sintered body of graphite or a mixture of graphite and metal powder such as copper. In this case, increasing the content of metal powder increases the strength of the brush body 1, and decreasing the content decreases the strength. Both sides 2 and 3 of the brush body 1 are provided with tapered parts that widen toward the head 4, and the corners between the head 4 and the tapered parts are rounded. That is, the head 4 of the brush body 1 has a substantially inverted trapezoidal shape.

The head 4 of the brush body 1 is accommodated in a groove-shaped holder portion 12 provided on a brush plate 11. The shape of the holder part 12 is similar to the inverted trapezoidal head 4 of the brush body 1.
It is assumed that the The brush plate 11 is made of an elastic metal such as phosphor bronze, and the holder portion 12 is provided by bending the brush plate 11, for example. Then, both edges of the holder part 12 and both side surfaces 2 and 3 of the brush body 1 are brought into contact with each other, and the holder part 12
The brush main body 1 is supported by pressure. In addition, small projecting pieces 13 and 14 are provided at the bottom of the holder part 12 as means for preventing horizontal vibration, and these are brought into contact with the brush main body 1 to press and support the brush main body 1 from directions other than both sides 2 and 3. To prevent lateral wobbling, caulking may be used instead of press support.

A through hole 17 is provided in the brush plate 11 between the bottom of the holder part 12 and the corners 15 and 16 between both edges. The through hole 17 extends along the center of the brush plate 11 from the corner 15 to the corner 16, and extends from the corner 15 to the corner 16.
At 16, it is expanding in a circular shape.

This brush is manufactured, for example, as follows. The corner part of the brush body 1 is connected to the corner part 1 of the holder part 12.
The brush main body 1 is attached to the holder part 12 while being brought into contact with one of the brush parts 5 and 16 and expanded around the corners 15 and 16 of the holder part 12. That is, with the holder part 12 slightly expanded, the head 4 of the brush main body 1 is inserted into the holder part 12 from an angle. In this way, the corner of the brush main body 1 reaches near one of the corners 15 and 16 of the holder part 12, and comes into contact with the brush plate 11 there. Next, from the side opposite to the contact position, the holder part 12 is expanded around one of the corners 15 and 16, and the other corner of the head of the brush main body 1 is inserted, and installation is completed. The center of expansion of the holder part 12 is the corner part 15,
16, stress during installation is concentrated on the corner of the brush body 1 that comes into contact with this. In the embodiment, a through hole 17 provided between the corners 15 and 16 allows the corner 1
The rigidity of the brush plate 11 at points 5 and 16 is reduced to prevent damage to the head of the brush body 1 during installation.

However, conventional brushes do not take this stress into consideration. When the size of the brush was increased and the thickness of the brush plate 11 was increased, stress from the corners 15 and 16 of the holder portion 12 to the corners of the brush body 1 increased, causing the brush body 1 to break from the corners. .

On the other hand, in this embodiment, the holder part 12
A through hole 17 is provided between the corner portions 15 and 16. This significantly increases the elasticity of the corners 15 and 16,
Even if the brush plate 11 is made thicker, the holder portion 12 can be easily expanded, and damage to the brush body 1 can be prevented.

A through hole 17 is formed between the corners 15 and 16 of the holder part 12.
Providing this does not reduce the performance of the brush.
The pressure for contact between the brush body 1 and a rotor (not shown) is determined by the elasticity of the R portion 18 of the brush plate 11. The R portion 18 here refers to the area between the lower edge of the corner 15 of the holder portion 12 and the root portion of the brush plate 11 (left side portion in the figure) in FIGS. 2 and 3. It means the R part. Therefore, even if the through hole 17 is provided between the corners 15 and 16 of the holder part 12, this R
This is because the portion 18 is not affected.

[Test example]

A brush with the structure shown in Figure 1 (conventional example) and a second
80 brushes (example) each shown in Fig. 3 and Fig. 3 were experimentally manufactured. The brush body 1 has a rectangular parallelepiped shape with a 6 mm square bottom and an inverted trapezoidal head with a height of 7 mm.
Phosphor bronze with a width of 6.5 mm and a thickness of 0.3 mm was used. In this case, in the conventional example, 69 out of 80 pieces were damaged during manufacturing, but in the example, all good pieces were obtained.

Although the specific shape of the through hole 17 has been described here, what is important is that the through hole 17 is provided between the two corners 15 and 16 to facilitate the expansion of the holder portion 12. Therefore, for example, a simple long groove-shaped through hole 17' as shown in FIG. 4 may be used.

For reference, a comparative example that was considered in the process of developing the present invention will be described.

[Comparative Example 1] In the brush shown in FIG. 1, we considered making the wall thickness of the holder portion 02 thinner than the other portions. However, due to residual stress due to the rolling process on the holder portion 02, the contact pressure between the brush body 1 and the rotor (not shown) became uneven.

[Comparative Example 2] In the brush shown in FIG. 1, the corner portion of the holder portion 02 was cut out from both sides to reduce the width of the corner portion. In this case, the pressure applied from the brush 01 to the brush main body 1 was uneven, resulting in poor contact between the brush and the rotor.

With this invention, it is possible to easily expand the holder portion during manufacturing and prevent damage to the brush body without impairing the pressure applied to the brush or the brush body.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional motor brush. FIG. 2 is a perspective view of the motor brush of the embodiment, and FIG. 3 is a front view thereof. FIG. 4 is a perspective view of a brush according to another embodiment. In the figure, 1...brush body, 4...head,
11...Brush plate, 12...Holder part, 15,
16... corner, 17, 17'... through hole, 18...
R section.

Claims (1)

[Claims for Utility Model Registration] The inverted trapezoidal head 4 of the brush body 1 is housed in a groove-shaped holder portion 12 provided on an elastic metal brush plate 11 and having a shape that almost matches the head 4. death,
Both sides 2 and 3 of the brush main body 1 are supported by pressure by both edges of the holder part 12, and at the bottom of the holder part 12 there is provided a means for preventing sideways movement of the brush main body 1 in directions other than both sides 2 and 3. small protrusions 13, 14
are provided, and these small projecting pieces 13 and 14 are attached to the brush body 1.
The corner portions 15, 1 between the bottom of the holder portion 12 and both edges of the holder portion 12 are brought into contact with the head portion 4 from a direction other than both sides 2, 3.
6, a through hole 17 is provided along the center of the holder portion 12.