JPS5950750A - Brush vibration preventing device for dc motor - Google Patents

Abstract

PURPOSE:To improve the lifetime of a brush by integrally forming a vibration preventing element made of polyurethane elastomer with the brush or a base plate which has the brush to automate the production, thereby reducing the cost and improving the sliding performance of a commutator. CONSTITUTION:A vibration preventing element 2a made of polyurethane elastomer is integrally mounted on a brush 1a or a base plate 1, on which the brush 1s is mounted. The element 2a is integrally formed on an insulating plate 4 on a bracket 3, and a base plate 1 may be projected from the element. The polyurethane elastomer does not generate organic gas due to plasticizer, and has excellent fusion resistance and oil resistance. The elastomer can be integrally molded to enable a mass production by an automation, and reducing the cost and improving the sliding performance of a commutator. The lifetime of the brush can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a brush vibration isolating device for a DC motor, which is used in household appliances and includes a vibration isolator to prevent brush vibration.

Structure of the conventional example and its problems Conventionally, as a brush vibration isolator for a small DC motor, as shown in FIG. As shown in FIGS. 2a and 2b, a method has been adopted in which the vibration isolating material 2 is placed closely in the direction of displacement of the substrate 1 to which the brush 1a or the bridge piece is attached to provide a vibration damping effect. Note that 3 in the figure is a bracket that supports two pages of the board 1 via an insulating plate 4. 5 is a bearing.

In FIG. 1, the vibration isolating material 2 is attached when the brush assembly is completed or after it is assembled into the bracket 3, and in FIG. 2, the vibration isolating material 2 is attached or formed by potting when the brush is assembled into the bracket 3. Therefore, the former method is often manual work and requires a lot of man-hours, but it is difficult to reduce the cost. The latter is relatively easy to automate, but requires special consideration for the brush shape and mounting structure in terms of vibration-proofing effects, which limits the range of application.

The vibration damping material 2 is generally made of natural or synthetic rubber, and since a plasticizer is used to adjust the hardness related to vibration damping properties, organic gas is generated during molding. It also has poor oil resistance. For this reason, it has been difficult to use a contact lubricant to eliminate manual work by integrally molding the brush and improve the life of the brush and commutator in order to reduce costs.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned drawbacks, reduces costs and provides a brush,
The purpose is to improve the lifespan of commutators, etc., and to improve the vibration-proofing effect.

3 - Structure of the Invention The present invention employs a polyurethane elastomer as a vibration damping material, and attaches it to a brush or a substrate having a brush by integral molding.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 to 5 of the drawings. Note that parts that are the same as those in the conventional example are given the same reference numbers and explanations will be omitted, and different parts will be explained.

That is, 2a is a vibration isolator made of polyurethane elastomer which does not generate organic gas due to plasticizer and has excellent solvent and oil resistance.

In FIG. 3, the brush 1a or the substrate 1 to which the brush is attached
A vibration isolator 2a is integrally attached to the
Figure 6 shows a structure in which the vibration isolator 2a is integrally molded on the insulating plate 4 on the bracket 3, and the substrate 1 is protruded from this.In short, the vibration isolator 2a is molded by integrally forming the brush 1a and the bracket 3. In this case, the aim is to provide vibration-proofing, soundproofing, and moisture-proofing effects.

By using the above-mentioned material as a vibration isolator, it becomes possible to perform integral molding, which was difficult in the past, and it is easy to select the optimal vibration isolation band for the brush. It becomes possible to use it.

Effects of the Invention According to the present invention, the scale using polyurethane elastomer as a vibration damping material is integrally molded with the brush or the substrate having the brush, so it is possible to reduce costs through automation, and to improve the vibration damping effect. We can expect great effects such as improved sliding performance of brushes and commutators through optimization, and longer life due to the ability to use contact lubricants.

[Brief explanation of drawings]

Figures 1 and 2a and 2b show a conventional DC motor. 1a: Brush, 2a: Vibration isolator, Name of agent: Patent attorney Toshio Nakao and 1 other person Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] Brush vibration isolator for a DC motor 0 in which a polyurethane elastomer is integrally molded as a vibration isolator on a brush or a substrate having a brush.