JPH0646215Y2 - DC motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a DC motor, and more particularly to a brush for a DC motor in which a rotor coil is energized through a brush and a commutator held by a holder on an insulating substrate. Regarding the improvement of the holding structure.

[Outline of device]

According to the present invention, a holder for holding a brush on an insulating substrate is provided with a locking piece, and the locking piece is inserted into a locking hole of the insulating board to be bent and bent at right angles to the locking piece. As described above, the claw is provided so that the claw comes into contact with the circumferential wall surface of the locking hole to prevent the holder from rattling.

[Conventional technology]

Generally, in a DC motor, it is necessary to switch the current according to the rotation angle of the rotor when energizing the rotor coil. Therefore, a commutator is used for such switching of the current, and a brush is pressed against the commutator to switch energization. A brush holder is provided to hold the brush, and the brush holder is attached to the insulating substrate.

[Problems to be solved by the invention]

The brush holder for holding the brush against the insulating substrate is provided with a locking piece so as to face the insulating substrate, and the locking piece is inserted into the locking hole of the insulating substrate and bent. The brush holder is thereby coupled to the insulating substrate. However, for example, when the locking hole is formed by punching on the insulating substrate made of Bakelite, if the size of the locking hole becomes too small, the punching die is easily damaged. It cannot be made small, and this causes looseness between the locking piece and the locking hole. This backlash has the drawback that the holder is pushed by the brush and moves. In addition, such movement causes the brush to tilt.

This will be described with reference to FIG.
If the circumferential width of the locking hole 3 of the insulating substrate for receiving the locking piece 2 is widened to protect the mold, the brush 4 tilts when worn. Brush 4 is brush holder 1
Since there is a gap in the circumferential direction of the rotary substrate between the brush 4 and the brush 4, when worn, the brush 4 tilts as shown by the chain line in FIG.

In such a state, the brush 4 is pushed in the rotation direction by the rotation of the commutator 5, and the opening portion on the tip end side of the brush holder 1 is spread as shown by the chain line. Since the brush holder 1 itself has elasticity, the brush 4 is sandwiched by this elasticity. When the brush 4 wears again. The coil spring 6 that presses the brush 4 against the commutator 5 expands, and the elastic restoring force of the coil spring 6 decreases. Therefore, the brush 4 fails to slide, and the motor finally stops rotating.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a DC motor that prevents a holder that holds a brush from moving and thereby avoids inclination of the brush. To do.

[Means for solving problems]

According to the present invention, in a DC motor in which a rotor coil is energized through a brush and a commutator held by an insulating substrate via a holder, locking pieces are provided at both lower ends of the holder. It is inserted into a locking hole formed on the insulating substrate so as to extend in the radial direction and bent in the circumferential direction of the insulating substrate, and with respect to the locking piece on the tip end side of the holder and on the rotation center side. Is provided at the base portion of the locking piece so as to be bent in the right angle direction and in the circumferential direction of the insulating substrate, and the claw surrounds the locking hole formed on the center side of the insulating substrate. The gap in the width direction of the locking hole is absorbed by making contact with the wall surface in the direction, thereby preventing rattling in the circumferential direction on the tip end side of the holder.

[Action]

Therefore, the locking pieces provided on the lower end portions on both sides of the holder are inserted into the locking holes formed on the insulating substrate so as to extend in the radial direction, and the locking pieces are bent in the circumferential direction of the insulating substrate. The bending allows the holder to be attached to the insulating substrate. A claw provided so as to be bent in the circumferential direction of the insulating substrate in a direction perpendicular to the locking piece on the tip side of the holder is provided in the locking hole formed on the center side of the insulating substrate. Prevents the tip of the holder from rattling in the circumferential direction and tilting the brush in the direction intersecting the radial direction because it contacts the wall surface in the circumferential direction and absorbs the gap in the width direction of the locking hole. To be done.

〔Example〕

The present invention will be described below with reference to an embodiment shown in the drawings. First, the overall structure of the motor according to one embodiment of the present invention will be described. The DC motor according to this embodiment includes a cylindrical casing 10 as shown in FIG. The casing 10 also serves as a yoke, and the openings formed on the front side and the rear side of the casing 10 are closed by a front bracket 11 and a rear bracket 12, respectively. Inside the casing 10, the stator core 13
And the stator coil 14 is wound around the stator core 13. A rotary shaft 15 is arranged so as to penetrate through the casing 10, and is rotatably supported by the front bracket 11 and the rear bracket 12 via bearings 16 and 17. Rotating shaft 15
A rotor yoke 18 is fixed to the rotor yoke 18, and a rotor coil 19 is wound around the rotor yoke 18.

Another bracket 20 is attached to the inside of the rear bracket 12, and this bracket 20 allows the insulating board to be installed.
Holding 21. The insulating substrate 21 has a circular hole in the center thereof and receives the commutator 22 held by the rotating shaft 15. A brush 23 is arranged on the outer peripheral side of the commutator 22 so as to come into contact with the commutator 22. The brush 23 is slidably held by a holder 24 and is pressed by a coil spring 25 so as to be pressed against the commutator 22. The brush 23 is electrically connected to a predetermined electric wire 27 of the cord 26.

Therefore, when the coil 19 of the rotor 18 is energized through the electric wire 27, the brush 23, and the commutator 22, a coil in which a current flows
19 receives a rotational force due to the magnetic field formed by the stator coil 14, which causes the rotor 18 to be rotationally driven. Then, this rotational force can be taken out through the rotary shaft 15.

Next, a brush that contacts the commutator 22 to switch the energization
The holding structure of 23 will be described. As shown in FIGS. 1 to 3, the brush 23 is held by a holder 24. And this holder 24 has four locking pieces 28
Are formed. These locking pieces 28 are particularly inserted into the locking holes 29 of the insulating substrate 21 shown in FIG. 2 and bent on the opposite side as shown in FIG. As a result, the holder 24 is fixed and attached to the insulating substrate 21. And holder
A claw 30 is formed at the root of the locking piece 28 on the center side of 24 so as to be bent laterally. As shown in FIG. 1, the claw 30 comes into contact with the side wall of the locking hole 29 on the center side of the insulating substrate 21 in the circumferential direction, thereby preventing the brush 24 from rattling in the circumferential direction. I try to prevent it.

As described above, according to the holding structure of the brush 23 according to the present embodiment, the side wall of the locking hole 29 formed with a large clearance with respect to the locking piece 28 is contacted due to the life of the punching die. Since the claw 30 is formed so that the brush 24 prevents the holder 24 from moving in the circumferential direction. Therefore, the holder 24 is prevented from moving in the circumferential direction and the brush 23 is prevented from tilting by a very simple structure and at a low cost. Therefore, abnormal wear of the brush 23 is prevented, or the brush 23 does not cause poor contact with the commutator 22.

[Effect of device]

As described above, according to the present invention, the locking pieces are provided at the lower end portions on both sides of the holder, and the locking pieces are inserted into the locking holes formed on the insulating substrate so as to extend in the radial direction. Is bent in the circumferential direction of the holder, and the pawl is bent so as to be bent in the circumferential direction of the insulating substrate in a direction perpendicular to the locking piece on the tip side of the holder and on the rotation center side. Is provided at the root portion of the engaging hole so that the claw comes into contact with the circumferential wall of the engaging hole formed on the center side of the insulating substrate to absorb the widthwise gap of the engaging hole. It is intended to prevent rattling in the circumferential direction on the tip side of the holder.

Therefore, according to the present invention, the claws connected to the base of the locking piece on the tip side of the holder are arranged in the circumferential direction of the insulating substrate having the locking hole for receiving the locking piece on the tip side of the holder. It is designed to bend at a right angle to the locking piece, and this claw absorbs the gap in the width direction of the locking hole on the center side, so that the width of the locking hole with respect to the locking piece is absorbed. Even if the size is increased, the tip of the holder does not rattle in the circumferential direction of the insulating substrate and the brush does not tilt in the direction intersecting the radial direction. Therefore, it is possible to increase the widthwise dimension of the portion corresponding to the locking hole of the die for punching the insulating substrate,
This makes it possible to prevent damage to the die for punching the insulating substrate. Further, since the tip of the assembled holder is prevented from rattling in the circumferential direction of the insulating substrate and the brush is prevented from inclining in a direction intersecting with the radial direction, the brush held by this holder is prevented from inclining to cause abnormalities. It becomes possible to eliminate wear and poor sliding.

[Brief description of drawings]

FIG. 1 is a front view showing a brush holding structure of a DC motor according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the same, FIG. 3 is an external perspective view of a holder, and FIG. FIG. 5 is a front view in which a part of the structure is cut away, and FIG. 5 is a front view showing a brush holding structure of a conventional DC motor. In the reference numerals used in the drawings, 19 ... rotor coil 21 ... insulating substrate 22 ... commutator 23 ... brush 24 ... holder 28 ... locking piece 29 ... locking hole 30 ... claw.

Claims (1)

[Scope of utility model registration request] 1. A DC motor in which a rotor coil is energized through a brush and a commutator held on an insulating substrate through a holder, and locking pieces are provided at lower end portions on both sides of the holder. Is inserted into a locking hole formed so as to extend in the radial direction on the insulating substrate and bent in the circumferential direction of the insulating substrate, and with respect to the locking piece on the tip end side of the holder and on the rotation center side. Is provided at the base portion of the locking piece so as to be bent in the right angle direction and in the circumferential direction of the insulating substrate, and the claw surrounds the locking hole formed on the center side of the insulating substrate. Direct current motor characterized in that it contacts the wall surface in the horizontal direction to absorb the gap in the width direction of the locking hole, thereby preventing rattling in the circumferential direction on the tip side of the holder. .