CN1203594C - Constant pressure carbon brush hold-down device for electric machine - Google Patents

Abstract

A motor carbon brush constant pressure pressing device belongs to the field of design of structural parts of electromechanical products, and in particular relates to the field of design of structural parts of motors. In order to solve the problem that the pressure on the carbon brush of a DC motor is required to be kept basically constant during the wear process, the invention discloses a constant pressure pressing device for a carbon brush of a motor, which includes a carbon brush and an elastic member placed in a brush holder, It is characterized in that the elastic member is a supporting spring, and the supporting spring contains a helical coil body, and a rotating arm protrudes from both ends of the coil body, and the lengths of the two rotating arms are equal, and the two rotating arms The end of the arm has a positioning structure, and is respectively supported on the carbon brush tail and the motor body. Using the present invention on a DC motor can improve efficiency, reduce noise, reduce calorific value, and greatly prolong the life of the motor.

Description

A motor carbon brush constant pressure pressing device

technical field

A motor carbon brush constant pressure pressing device belongs to the field of design of structural parts of electromechanical products, in particular to the field of design of structural parts of motors.

Background technique

DC motors are divided into two categories: brushed and brushless motors. Among them, brushed DC motors realize the commutation of current through the contact of carbon brushes and commutators. In order to ensure that the carbon brush is always in contact with the commutator during wear, a spring is generally installed at the end of the carbon brush. During the wear of the carbon brush, the spring always pushes the carbon brush forward to withstand the surface of the commutator to ensure the smooth flow of electricity. .

There are two types of traditional carbon brush springs: helical compression spring and helical torsion spring. Both spring modes of action have a common disadvantage, that is, at the beginning (new carbon brushes) and at the end (carbon brushes are worn to the end), the spring pressure on the carbon brushes varies greatly. In order to reduce the pressure change, the only way is to lengthen the free length of the spring, but this is difficult to achieve due to structural limitations in most occasions. Even if the free length is slightly lengthened, there is still a 3-4 times difference between the initial and final pressure.

For the motor, this pressure has an optimum value. Excessive pressure will cause a series of problems such as excessive friction resistance, reduced motor efficiency, increased heat generation, increased noise, and accelerated carbon brush wear; too small pressure may cause poor contact, ignition and unstable speed, etc. , causing the above-mentioned problems as well.

Contents of the invention

The object of the present invention is to provide a constant pressure pressing device for carbon brushes of DC motors in order to solve the problem that the pressure on the carbon brushes of DC motors should be basically kept constant during the wear process.

In order to achieve the above object, the technical scheme provided by the invention is as follows:

A motor carbon brush constant pressure pressing device, including a carbon brush placed in a brush holder and an elastic member, characterized in that the elastic member is a support spring, and the support spring contains a helical coil body, a coil One rotating arm protrudes from both ends of the body, and the lengths of the two rotating arms are equal. The ends of the two rotating arms have positioning structures and are respectively supported on the tail of the carbon brush and the motor body.

The positioning structures of the ends of the two pivoting arms of the support spring in the motor carbon brush constant pressure pressing device are bent angles facing the carbon brush and the motor body respectively.

The tail of the carbon brush in the motor carbon brush constant pressure pressing device and the motor body respectively have dimples matching the positioning structures at the ends of the two rotating arms.

The motor carbon brush constant pressure pressing device can also include an insulating block, the insulating block is fixed on the motor body, and the ends of the two rotating arms of the support spring are respectively supported on the tail of the carbon brush and the insulating block. on the block. The positioning structures of the ends of the two pivoting arms of the support spring are bent angles facing the carbon brush and the insulating block respectively. The tail of the carbon brush and the insulating block respectively have dimples matching the positioning structures at the ends of the two rotating arms.

The experiment of the present invention on a certain DC motor shows that under the same conditions of use, the working life is extended by 2-3 times, and the effects of improving efficiency, reducing noise, reducing heat generation and greatly extending life are realized.

Description of drawings

Fig. 1 is a schematic diagram of a carbon brush pressing device using a helical compression spring in the prior art.

Fig. 2 is a schematic diagram of a carbon brush pressing device using a helical torsion spring in the prior art.

Fig. 3 is a schematic diagram of an embodiment of the motor carbon brush constant pressure pressing device of the present invention.

Fig. 4 is a schematic diagram of another embodiment of the present invention.

Detailed ways

Figure 1 is a schematic diagram of a carbon brush pressing device using a helical compression spring spring in the prior art. The helical compression spring 6 is placed in the brush holder 5 to support the tail of the carbon brush 4, and the carbon brush can slide in the brush holder , whose head is in contact with the commutator 3 on the motor rotor. The carbon brush lead wire 7 is connected with the carbon brush 4, and it is a channel for current input and output.

FIG. 2 is a schematic diagram of a carbon brush pressing device using a helical torsion spring in the prior art. One end of the torsion spring 8 bears against the tail of the carbon brush 4 , and the other end of the torsion spring 8 is fixed by a torsion spring frame 9 .

In the above two solutions in the prior art, during the process of carbon brush wear, the pressure on the carbon brush changes greatly, which will cause a series of problems.

An embodiment of the present invention is shown in FIG. 3 . The motor carbon brush constant pressure pressing device includes a carbon brush 4 placed in a brush holder 5 and a support spring capable of providing constant pressure. The carbon brush lead wire 7 is connected with the carbon brush 4, and it is a channel for current input and output. The head of the carbon brush 4 is in contact with the commutator 3 on the DC motor rotor. The coil body 1 of the supporting spring is wound in a helical shape, and the two ends of the coil body respectively protrude from the rotating arm 2, and the supporting spring is in a free state; The pits and the pits on the motor body 10. The bending angle at the end of the rotating arm, the effect of the pits on the tail of the carbon brush and the motor body are to make the position of the end of the rotating arm difficult to slip off during the stretching process of the support spring.

The working principle of the present invention is described as follows: the supporting spring in a free state produces two pressures of equal magnitude and opposite directions to the carbon brush 4 and the motor body 10 simultaneously. During the working process of the DC motor, the carbon brush 4 will gradually wear out, and the two arms of the support spring can be gradually stretched; the support spring can be stretched freely, and the pressure on the carbon brush will only occur slightly in a large working range. The change. The pressure remained essentially constant (<10% variation) until the carbon brushes were worn to the end.

Another embodiment of the present invention is shown in Figure 4, there is also an insulating block 11 in the motor carbon brush constant pressure pressing device, the insulating block 11 is fixed on the motor body 10, and the curved angles at the ends of the two pivoting arms of the supporting spring are pushed up respectively. Hold the pit at the tail end of the carbon brush 4 and the pit on the insulating block 11.

The present invention is not limited to the above-mentioned embodiments, and any changes in shape and structure on components such as the end of the support spring arm and the tail of the carbon brush belong to the scope of protection of the present invention.

Claims (6)

1. A motor carbon brush constant pressure pressing device, comprising a carbon brush and an elastic member placed in a brush holder, characterized in that the elastic member is a support spring, and the support spring contains a helical coil body, A rotating arm protrudes from both ends of the coil body. The lengths of the two rotating arms are equal. The ends of the two rotating arms have positioning structures and are respectively supported on the tail of the carbon brush and the motor body. 2. The motor carbon brush constant pressure pressing device according to claim 1, characterized in that the positioning structures of the ends of the two pivoting arms of the support spring are bent angles respectively facing the carbon brush and the motor body. 3. The motor carbon brush constant pressure pressing device according to claim 2, characterized in that the tail of the carbon brush and the motor body respectively have pits matching the positioning structures at the ends of the two rotating arms. 4. The motor carbon brush constant pressure pressing device according to claim 1, characterized in that the motor carbon brush constant pressure pressing device also includes an insulating block, the insulating block is fixed on the motor body, the The ends of the two rotating arms of the support spring are respectively supported on the tail of the carbon brush and the insulating block. 5. The motor carbon brush constant pressure pressing device according to claim 4, characterized in that the positioning structures of the ends of the two pivoting arms of the support spring are bent angles facing the carbon brush and the insulating block respectively. 6. The constant pressure pressing device for motor carbon brushes according to claim 5, characterized in that the tails of the carbon brushes and the insulating block respectively have dimples matching the positioning structures at the ends of the two rotating arms.

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