JP2009072037A - Manufacturing method of interruption brush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interruption brush with improved service life and productivity. <P>SOLUTION: The interruption brush 1 protrudes an insulating pin 6 built in a brush main body 2 to a commutator by an elastic force of a spring 7 to break current, when the brush main body 2 to feed power to the commutator of a motor reaches a wear limit. In the interruption brush, the pin 6 is inserted into a hole 3 of a predetermined depth in one end of the brush main body 2, a plurality of saw-tooth protrusions are formed in the outer periphery of the hole on the spring 7 mounted at the back side of the pin 6, and a metal lid with these protrusions internally bent at a predetermined angle is put on the pin 6. Further, the spring 7 is compressed by pushing the lid, and the extremity of the protrusion is brought inside the hole 3 to fit the lid tightly. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a blocking brush used in a motor.

  Various cutoff brushes have been proposed that have a function of stopping the motor by cutting off the current when the brush body that supplies power to the commutator of the motor reaches the wear limit. FIG. 5 shows an example of a conventional blocking brush a. A method of manufacturing the blocking brush will be described with reference to FIG. 6. A plastic pin d and a spring e are inserted into a hole c formed in the head of the brush body b, and a circular cardboard is placed on the spring e. A number of operations are performed in which the spring is compressed by pressing with a tool after covering with f, and then the copper powder g filled on the cardboard f is beaten with the tool to harden the copper powder g (copper powder stopping). The spring e is held in a compressed state by repeating the rotation. And the adhesive agent h is apply | coated and the reinforcement is performed on the location which gave the copper powder stopper. j is a lead wire provided on the brush body b.

  In Patent Document 1, a spring is compressed by inserting a shut-off piece and a spring into a screw hole formed in the head of the brush body and then screwing the saucer, and a lead wire is placed on the saucer. A structure in which is fixed with copper powder is disclosed.

  In the former manufacturing method, in order to insert the pin c and hold the spring d in a compressed state, it is necessary to fill the copper powder with a height of 2 mm or more. Will return to its original length, or it may cause inconvenience of pushing out the copper powder and jumping out.

In the blocking brush disclosed in Patent Document 1, the operation of setting the spring inserted by screwing the tray into the screw hole of the brush body in a compressed state is complicated because each component is small. I can say that.
Japanese Utility Model Publication No. 61-43771

  The objective of this invention is providing the manufacturing method of the interruption | blocking brush which improved the lifetime and productivity of a brush.

  In order to achieve the above object, according to the first aspect of the present invention, when a brush body supplying power to a commutator of a motor reaches a wear limit, an insulating pin incorporated in the brush body is spring-loaded. In a blocking brush provided to jump out toward the commutator by the elastic force of the current to block the current, the pin is inserted into a hole of a predetermined depth formed in one end of the brush body and A plurality of serrated protrusions are provided on the outer peripheral edge of the spring mounted on the rear part of the pin, and a metal lid piece is formed by bending the protrusions inward at a predetermined angle. The cover piece is pressed to bring the spring into a compressed state, and the tip of the protrusion is bitten into the inner surface of the hole to fix the cover piece.

  In order to achieve the same object, the invention described in claim 2 is the manufacturing method of the blocking brush according to claim 1, wherein a circular plate having the same diameter as the inner diameter of the hole is placed on the spring. The metal lid piece is covered with the above.

(Invention of Claim 1)
According to this method of manufacturing a blocking brush, the spring that urges the pin in the direction of popping out the pin can be held inside the brush body by the metal lid piece, so that the copper powder stopper used in the conventional manufacturing method is used. The production process is simplified and the productivity is improved, and the depth of the hole for accommodating the pin and spring can be reduced by about 1.0 to 1.5 mm, which increases the effective wear amount of the brush body and increases the life of the brush. become longer.

(Invention of Claim 2)
According to this method of manufacturing a blocking brush, a circular plate having a diameter substantially the same as the inner diameter of the hole of the brush body is put on the spring and then the metal lid piece is covered. Work can be performed smoothly.

  The best mode to which the present invention is applied will be described below with reference to the drawings. 1 is a front view of a blocking brush according to the manufacturing method of the present invention, FIG. 2 is an explanatory view showing a manufacturing process of the blocking brush according to the manufacturing method of the present invention, and FIG. 3 is a plan view (A) and a front view of a metal lid piece (B), FIG. 4 is a schematic diagram for explaining a state in which the protrusion of the metal lid piece has bitten into the inner surface of the hole.

  A blocking brush 1 to which the manufacturing method of the blocking brush according to the present invention is applied is shown in FIG. Below, the structure and manufacturing process of this interruption | blocking brush 1 are demonstrated collectively. In the figure, a hole 3 having a predetermined depth, that is, a depth of 6 mm and a diameter of 2.5 mm is formed in one end portion 2 a of the carbon brush body 2 of the blocking brush 1. In a hole (not shown) formed near the hole 3, the lead wire 5 is fixed by accommodating one end portion of a known lead wire 5 and applying copper powder.

  Into the hole 3, as shown in FIG. 2 (a), an insulating plastic pin 6 and a spring 7 attached to a rear portion 6b formed narrower than the head portion 6a of the pin 6 are inserted together. To do. Then, a cover piece 8 made of metal, in this embodiment copper, is placed on the spring 7.

  As shown in FIG. 3, the copper lid piece 8 has a substantially disk shape with a thickness of 0.3 mm and a diameter of about 2.4 mm. In this embodiment, a plurality of pieces are formed on the outer peripheral edge of the flat central portion 9. Three sawtooth-shaped protrusions 10 are provided on the left and right end edges 9a, respectively, and the protrusions 10 are bent inward at a predetermined angle, here, 45 degrees.

  After the cover piece 8 is put on the spring 7 as described above, the spring piece 7 is compressed by pressing the cover piece 8 with a metal rod (not shown) as shown in FIGS. The lid piece 8 is fixed by bringing the tip of the serrated protrusion 10 into the inner surface of the hole 3 in a state (FIG. 4).

  And the blocking brush 1 which concerns on this invention manufacturing method is comprised by apply | coating the adhesive agent 12 on the cover piece 8, and providing reinforcement. In this blocking brush 1, since the depth of the hole 3 into which the pin 6 is inserted can be reduced by about 1.0 to 1.5 mm compared to the conventional manufacturing method, the effective wear amount increases by 1 mm if the depth is reduced by 1 mm. About 15% longer life.

    In this embodiment, the metal lid piece 8 is directly covered on the spring 7 (invention of claim 1), but a circular plate such as cardboard having the same diameter as that of the hole is put on the spring. It can also be set as the structure which covered the metal lid piece after this (invention of Claim 2).

  In addition, the load when pressing the metal lid piece 8 and causing the saw-tooth projection 10 to bite into the inner surface of the hole 3 needs to be larger than the compression load of the spring 7, but if it is smaller, the spring 7 is compressed. The protrusion 10 of the metal lid piece 8 starts to open before the occurrence of such a problem, such as a decrease in holding force and a weakening of the force of the pin 6 protruding at the time of blocking. The load when the protrusion 10 of the metal lid piece 8 is opened varies depending on the material, thickness, etc., but it is important to select an appropriate load according to the compression load of the spring 7.

(Experiment)
In the blocking brush 1 according to the method of the present invention, an experiment was conducted on the holding force (holding strength) by the metal lid piece 8. The results are shown in Table 1.

  According to the results of the experiment, the holding force was 57.81 N on average. Incidentally, the holding force in the case of the blocking brush which covers the conventional spring with a thick paper and stops the copper powder is 60N on average (however, the standard value is 30N or more). Therefore, it was confirmed that the holding force of the blocking brush 1 according to the method of the present invention is substantially equal to the holding force of the blocking brush according to the conventional method.

  As described above, according to the manufacturing method of this blocking brush, the copper powder stopper employed in the conventional manufacturing method is no longer necessary, so the production process is simplified and the productivity is improved. Therefore, there is an advantage that the effective wear amount of the brush body is increased and the life of the brush is extended.

Front view of blocking brush according to manufacturing method of the present invention Explanatory drawing which shows the manufacturing process of the interruption | blocking brush which concerns on this invention manufacturing method Top view (b) and front view (b) of metal lid Schematic diagram explaining the state in which the protrusion of the metal lid piece bites into the inner surface of the hole Front view of a blocking brush according to a conventional manufacturing method Explanatory drawing which shows the manufacturing process of the interruption | blocking brush which concerns on the conventional manufacturing method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Blocking brush 2 ... Brush body 2a ... One end 3 ... Hole 6 ... Pin 7 ... Spring 8 ... Metal lid piece 10 ...・ Sawtooth projection

Claims (2)

When the brush body that supplies electric power to the commutator of the motor reaches the wear limit, an insulating pin built in the brush body jumps out toward the commutator by the spring force of the spring to generate current. In the blocking brush provided to block,
Inserting the pin into a hole of a predetermined depth formed at one end of the brush body, and a plurality of serrated protrusions projecting on the outer peripheral edge on the spring mounted on the rear portion of the pin, and The protrusion is covered with a metal lid piece bent inward at a predetermined angle, and then the spring is compressed by pressing the cover piece, and the tip of the protrusion is placed on the inner surface of the hole. A method for manufacturing a blocking brush, wherein the lid piece is fixed by biting.   2. The method for manufacturing a blocking brush according to claim 1, wherein a circular plate having a diameter substantially the same as the inner diameter of the hole is put on the spring and then the metal lid piece is covered.

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