JPH0226214Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a brush device for a DC motor used as an engine starting motor.

Conventionally, a brush device for a DC motor as described above was described in Japanese Utility Model Application Publication No. 53-127205. The relationship diagrams of this brush device are reproduced from FIG. 1 to FIG. 3, and will be summarized and explained below.

In FIG. 1, reference numeral 1 denotes an end bracket constituting a part of an engine starting motor. This bracket 1 is made of a conductive material such as a mild steel plate, and is grounded to the outer shell of the main body of the DC motor. In FIGS. 1 to 3, reference numeral 2 denotes a brush holding board fixed to the end bracket 1 by screws 3 made of a conductive material. Screw holes 2a for screwing are formed at two locations in the direction. 4 is the above holding substrate 2
The insulating plate is fixed to two places, respectively, and through holes 4a for fixing are formed in two places. 5
is a positive side brush retainer which is a first retainer caulked and fixed to the holding substrate 2 via the insulating plate 4, and this retainer 5 is made of a conductive metal plate and will be described later together with the insulating plate 4. It has a brush holding part 5a for holding a brush, a spring mounting part 5b formed on one side of this holding part 5a, and a burring part 5c formed protrudingly on the holding part 5a for caulking. There is. Reference numeral 6 denotes a positive side brush which is a first brush, and this brush 6 is slidably inserted into the holding portion 5a. 7
is a brush spring attached to the spring attachment portion 5b, and this spring 7 presses the plus side brush 6 in one direction. Reference numeral 8 denotes a commutator that is attached to the armature of the DC motor and constitutes a power supply section, and the positive side brush 6 is always slidably pressed against the outer peripheral surface of the commutator 8. Reference numeral 9 denotes a positive lead wire, one end of which is electrically connected to the positive brush 6, and the other end electrically connected to a field coil (not shown). 12 is a minus side brush holder which is a second brush holder;
Reference numeral 2 is made of a conductive metal plate, and is directly caulked and fixed to the holding board 2, forming a brush holding part 12a that holds the brush together with the holding board 2, and a spring mounting part 11 to which the brush spring 7 is attached.
b and a burring part 11c for caulking are formed. 12 is the minus side brush retainer 1
This is a second brush, that is, a minus side brush, which is slidably inserted into the holding portion 11a of No. 1, and is always slidably pressed against the outer circumferential surface of the commutator 8 by the spring 7. 13 is a negative lead wire, and this lead wire 13 is connected to the holding board 2.

In the conventional device configured as described above, when an engine is started, a power supply (not shown) connects the positive lead wire 9 → the positive brush 6 → the commutator 8 → the negative side via a field coil (not shown). A closed circuit is formed from the side brush 12 to the negative lead wire 13 to the holding board 2 to the end bracket 1 to the ground, and the engine starting motor is energized to generate rotational force to start the engine.

In this conventional brush device, since the holding substrate 2 and the brush holder 5 are made of a conductive material, when the holder 5 and the insulating plate 4 are caulked and fixed, as shown in FIG. Processing section 5
At c, the insulation resistance between the holding substrate 2 and the burring part 5c decreases due to abrasion powder of the brush 6 or 12 adhering to the surroundings of the protruding parts of the caulking fixing parts A and B. There is a drawback that the power supply voltage flows to the holding substrate 2 via the brush holder 5, that is, leakage current occurs.

This invention is an attempt to solve the above-mentioned drawbacks of the conventional ones, and has a simple structure by insulating the burring part of the brush holder or the holding board with a resin insulating material with a flange. The object of the present invention is to provide a brush device for a motor in which the electrical insulation properties of the device are improved.

An embodiment of this invention will be described below with reference to FIGS. 4 and 5.

In FIGS. 4 and 5, 14 is a bushing made of a molded material of insulating synthetic resin. The cylinder part 16 is elastically fitted into the burring part 5c, and the flange part 1
5, the caulked and fixed portions of the brush holder 5 and the insulating plate 4 are covered from above by the burring portion 5c. The configuration of this embodiment other than that described above is the same as the conventional brush device shown in FIGS. 1 to 3, so the same or corresponding parts as in FIGS. 1 to 3 are designated by the same reference numerals. 4 and 5, and the explanation will be omitted.

In the brush device of the above-described embodiment, the caulked and fixed parts A and B by the burring part 5c are attached to the bush 1.
Since the flange 15 of 4 is insulated, conductive substances such as brush abrasion powder will not directly adhere to the crimped and fixed parts A and B by the burring part 5c, and leakage current to the brush holding board 9 will be eliminated. .

The above-mentioned embodiment is a case in which the brush holder is provided with a caulking fixing part by a burring part to the insulating plate, but this invention provides a burring part to the brush holding board and caulking the part to the insulating plate. The present invention can also be applied to cases where the above embodiment is used, and the same effects as those of the above-mentioned embodiments can be obtained in this case as well.

As explained above, according to this invention, a burring part is formed on the brush holding substrate or the brush holder, and the fixed part is caulked and fixed to the insulating plate.
Since the flange provided on the resin insulating bushing is covered with a cap, the insulation of the motor brush device can be improved with a simple structure without compromising compatibility with conventional brush devices. It will be done.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view showing a brush device of a conventional electric motor, Fig. 2 is a plan view showing the main parts of Fig. 1, Fig. 3 is a sectional view taken along the - line in Fig. 2, and Fig. 4
The figure is an enlarged sectional view of the same part as FIG. 3 showing the essential parts of a brush device for an electric motor according to an embodiment of the invention, and FIG. 5 is an external perspective view of the brush. 1... End bracket (motor housing), 2
...Brush retainer, 3...Screw, 4...Insulating plate,
5... Holding board, 5c... Burring processing part, 6
... Brush, 14 ... Bush (resin insulation material),
15...Trim part, 16...Cylinder part. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) The brush holding board screwed onto the motor housing and the brush holder slidingly contacting the commutator are each made of a metal plate, and the board and the holder are made of an insulating plate. In a brush device for an electric motor that is fixed via a burr, a burring part is formed on the holding substrate or the retainer and is caulked and fixed to the insulating plate, and a flange formed on a resin insulating material is covered with the caulked and fixed part. An electric motor brush device characterized by: (2) The electric motor brush device according to claim 1, wherein the electric motor is a DC motor for engine starting.