JPS5845488Y2 - brush retainer - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a brush holder used in rotating electric machines, particularly small DC motors equipped with brushes that come into sliding contact with a commutator.

Conventionally, this type of brush holder has generally been constructed as shown in FIGS. 1 and 2.

In the figure, 1 is a brush box, 2 is a brush that is slidably fitted into the brush box 1, and 3 is a plate-shaped spiral spring with a certain width for pressing this brush 2 against the commutator surface CM. .

4 is the brush box 1 for holding this spiral spring 3.
a spring shaft protruding from the spiral spring 3;
A cotter pin 5 is inserted to prevent it from coming out.

Reference numeral 6 denotes a terminal screw provided in the brush box 1 for electrically connecting the connection string of the brush 2 and the like.

The brush box 1 is fixed to a holding plate 7 at predetermined intervals with rivets 8 or the like, and is attached to the rotating electric machine frame using holes 7a or the like.

The brush holder constructed in this manner has a brush 2 fitted into a brush box 1 so as to be slidable thereon, and the other end of a spiral blade 3 whose inner end is engaged with a spring shaft 4 protruding from the brush box 1. The brushes 2 are brought into contact with each other, and the stored force of the spiral spring 3 serves to press the brush 2 against the commutator surface CM with a predetermined pressure.

In addition, the brush box 1 is provided with a notch 1a corresponding to the width of the spiral spring 3 at the part where the spiral spring 3 contacts the brush 2, so that even if the brush 2 gradually wears out due to sliding contact with the commutator, the specified brush The stored force of the spiral spring 3 can be utilized without being obstructed by the brush box 1 up to its length.

Conventional brush holders are constructed as described above, but due to the mounting structure of the spiral springs, the spiral springs protrude laterally from the brush box, which increases the width of the brush holder. If the space between the brush holders becomes extremely small, for example, if a holder plate is attached to the frame of a rotating electrical machine, or if screws for connecting the frames are installed in the space between the brush holders, the inside of the rotating electrical machine may When the holding plate is rotated left and right with respect to the frame during sex point adjustment, there is a concern that the screws and the brush holder may come into contact with each other and short-circuit, so it is necessary to increase the outer diameter of the rotating electric machine frame.

In addition, in rotating electric machines that rotate in both left and right directions, the direction of suppression of the spiral spring that is in contact with the top surface of the brush is biased toward the opposite direction of the spring shaft, whereas the force that the sliding contact surface of the brush receives depends on the direction of rotation. Since the brushes are in the same direction or in opposite directions, the contact between the brush and the commutator becomes uneven due to the fitting gap between the brush and the brush box, which tends to cause sparks.

This invention was made to eliminate the above-mentioned drawbacks of the conventional brush holder, and its purpose is to provide a compact brush holder that can provide stable brush contact by changing the mounting structure of the spiral spring.

An embodiment of this invention will be described below with reference to the drawings.

3 to 5, 1 is a brush box, 2 is a brush that is slidably fitted into the brush box 1, 3 is a spiral spring for pressing this brush 2 against the commutator surface CM,
This is a spring shaft for holding the spiral spring 3 of the four-barrel.

Here, the spring shaft 4 protrudes symmetrically from both sides of the brush box 1, and may be formed integrally with the brush box by precision casting, for example, or may be formed through the brush box. A single spring shaft may be press-fitted and fixed, and each of its ends is provided with a slit 4a in which the inner end of the spiral spring 3 engages, and a split pin 5 is inserted to prevent the spiral spring 3 from being pulled out. ing.

The spiral springs 3 are made of two plate-shaped pieces having the same shape, and each of the inner ends is inserted into the slit 4a of the spring shaft 4 as described above.
The other end is formed into a ring shape and is engaged with a pin 9 having flanges at both ends, and the pin 9 is connected so as to straddle the brush box 1 and abut against the brush 2.

Reference numeral 6 denotes a terminal screw for electrically connecting the connection string of the brush 2, etc., and is provided using the central portion of the brush box 1 from which the spring shaft 4 protrudes.

The brush box 1 is fixed to a holding plate 7 at predetermined intervals with rivets 8, etc., and is attached to the rotating electric machine frame using holes 7a, etc., to hold the brushes 2 at a fixed position on the commutator surface CM. ing.

Therefore, since there is no laterally protruding portion of the brush box 1, the flan holder can be made smaller, and the space between each brush holder can be increased.

In addition, the two spiral springs 3 have their inner ends engaged with the spring shafts 4 that protrude from both sides of the brush box 1, and the other ends are connected by pins 9, so that the pins 9 straddle the brush box 1 and connect to the brush 2. When the brush 2 is attached to or removed from the brush box 1, the pin 9 is pulled up to the position shown in FIG. 5A so as to simultaneously wrap the spiral springs 3 on both sides. Even if the brush box 1 gradually wears out due to sliding contact with the brush 2, if the brush box 1 is provided with sparks 1a on both sides corresponding to the position of the pin 9 that contacts the brush 2, the brush box 1 can be kept in a predetermined state as shown in FIG. 5B. Since the stored force of the spiral spring 3 can be used up to the length of the brush, and the stored force of both spiral springs 3 is evenly applied to the pin 9 across the brush box 1, the force that presses the brush 2 against the commutator [nCM] is always in the vertical direction. Therefore, even when used in a rotating electrical machine that rotates in both rotational directions, contact with the brush commutator surface is stable and the generation of sparks can be suppressed.

In the above embodiment, since the spiral spring 3 engaged with the slit 4a of the spring shaft 4 does not come out, split pins 5 are inserted at both ends of the spring shaft. Since they are joined together at the collar 9 so as not to spread outward, even if the split pin 5 is omitted, it will not come out easily.

Further, although the spring shaft 4 is projected toward the retaining plate γ with respect to the brush fitting position of the brush box 1, it is clear that the relative position of the brush fitting position and the spring shaft 4 and the terminal screw 6 can be configured as desired.

As described above, in the brush holder of this invention, a pair of spring shafts protrudes symmetrically from both sides of the brush box, the inner ends of the spiral springs are engaged with the spring shafts on both sides, and the other end is connected to the pin that straddles the brush box. The pin is connected at both ends, and the central part of the pin is brought into contact with the brush, so that the brush is pressed against the commutator surface by the accumulated force of both spiral springs, so there is no part that protrudes laterally of the brush box, and the brush holder can be easily moved. Since it can be made compact, the space between each brush holder can be used widely and effectively, and the outer diameter of the rotating electrical machine frame can be reduced. Also, since the same shaped spiral springs can be used on both sides of the brush box, the spring force is uniform. Therefore, the force that presses the brush against the commutator surface always acts in the vertical direction, and even when used in rotating electric machines that rotate in both directions, stable brush contact can be obtained and the contact between the brush and commutator surface is maintained. This has the effect of suppressing sparks generated from the parts.

[Brief Description of the Drawings] Fig. 1 is a front view showing a conventional brush holder, Fig. 2 is a top view of Fig. 1, and Fig. 3 is a front view showing a brush holder according to an embodiment of the invention. , Figure 4 is a top view of Figure 3, and Figure 5 is a top view of Figure 3.
The figure is a side view of FIG. 3. Explanation of symbols, 1...Brush box, 2...Brush, 3.
...Spiral spring, 4...Spring shaft, 4a...Slit, 9...Pin, 1a...Notch. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] a brush box, a pair of spring shafts protruding symmetrically from both sides of the brush box, and a slit provided at the tip of the spring shaft;
The inner ends of the spiral springs are engaged with the slits, and the other ends are connected to both ends of a pin that straddles the brush box, and notches are provided on both sides of the brush box corresponding to the positions of the pins. A brush holder that presses the brush by abutting the central part of the brush against the brush.