JPH11275816A - Brush for small size motor and method of manufacturing the brush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent for generation of cracks and assure maximum application rate of material by setting the rolling trace direction to be in a direction different from that of the coil material line. SOLUTION: The rolling trace direction d of a coil material 13 is set forming the right angle with the line direction of a coil material 13 with the use of a repeated cross rolling device. Moreover, a brush 4 is blanked at the right angle to the line direction of coil material 13. The blanked brush 4 is bent at a right angle for the straight line B1-B2 as a border. Therefore, the bending line B1-B2 of the brush 4 is formed at right angles to the rolling trace direction d. Therefore, at the bending corner, cracks will not be generated. Accordingly, maximum utilization factor of material can be obtained and the rolling trace d of the coil material 12 as the raw material can be set at a right angle to the bending line of brush 4 at a low cost, so that the brush 4 having the strength such that cracks in the bending area will not occur can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of brushes for micromotors, and more particularly to the manufacture of brushes having a low cost and excellent strength.

[0002]

2. Description of the Related Art In recent years, brushes of small DC motors with brushes, called micromotors, have been demanded for energy saving, compactness, and noise reduction. A thin plate spring brush system having a spring structure, in particular, a thin metal plate structure in which a commutator and a sliding portion are bonded with a noble metal has been generally adopted.

[0003] In order to form the plate brush at low cost and efficiently, punching, bending and cutting are performed by an automatic press. In addition, this brush may use expensive precious metal or the like in part, and a blank layout is devised so as to maximize the utilization rate of the material in punching.

[0004] A conventional micromotor brush and a method of manufacturing the same will be described below. FIG. 2 is a general structural diagram of a micromotor. In FIG. 2, the motor shaft 7 is connected to the motor shaft 7 from the terminal 6 held by the bracket 2 via the brush 4 that contacts the commutator 3 and the commutator 3 fixed to the motor shaft 7 supported by bearings 5a and 5b. When a current is supplied to the rotor coil 9 wound around the fixed laminated core 8, the rotor 1 existing in the magnetic field formed by the magnet 10 fixed to the inner peripheral surface of the motor housing 1 is provided.
1 is configured to rotate.

FIG. 3 is a sectional view taken along the line A1-A2 of FIG. A noble metal a is adhered to a portion of the brush 4 which slides with the commutator 3, and the other end b is bent into an L-shape and is fixed to the terminal 6 at a portion c by spots or caulking.

FIG. 4 shows an example of a blanking step and a bending step in a conventional brush 4 press. In FIG. 4A, reference numeral 13 denotes a part of the coil material in which the roll d of the material of the brush 4 is processed in parallel with the material strip.
Further, a is a noble metal portion made of gold, silver, an alloy thereof, or the like bonded to the coil material. Generally, a brush blank made of a noble metal or the like is used in a manner similar to that shown in FIG.
Blanked at right angles as in (a). FIG. 4 (b) shows the brush 4 which has been blanked, and is brushed at a right angle on a straight line B1-B2. The bent one is shown in FIG.

[0007]

However, disadvantages of the prior art include the following. Generally, a thin metal plate is produced by rolling, and a metal composition direction called a roll is formed. However, if the bending line is aligned with the roll direction in the bending step of the press, cracks occur in the bending corners.

This will be described below with reference to FIG. Since the coil material of the brush is rolled in the strip direction, the roll d is formed in a direction parallel to the strip of the coil material 13. Here, when the brush 4 is bent at a right angle with respect to the line B1-B2 as shown in FIG. 4 (b), the bending line B1-B2 is parallel to the roll d, so that the bending corner b is cracked. . This causes problems in the motor and causes a remarkable reduction in life.

Conventionally, as a countermeasure against cracking of the above problem, there is a blank as shown in FIG. 5 at an angle of 45 degrees with respect to the roll direction, but the loss of material increases, and especially when a noble metal member is used, noble metal is used. The problem arises that the amount of material used increases and the cost of the material increases. An object of the present invention is to provide an inexpensive and strong brush and a method for manufacturing the brush.

[0010]

According to a first aspect of the present invention, there is provided a brush for a small motor in which a commutator slides into a plurality of ends and the tip of which is slid is formed of a conductive metal sheet. Is not matched with the coil material direction. A brush manufacturing method for a small motor according to claim 2, wherein the brush is formed by a conductive metal thin plate having a noble metal adhered to a tip end on which a commutator slides, wherein the conductive metal plate is rolled in a roll direction. , And the longitudinal direction of the brush arm is blanked at right angles to the direction of the strip of the conductive metal sheet.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIG. FIG. 1A is a view of a brush blank of a micromotor according to an embodiment of the present invention. The direction of the roll d of the coil material 13 is rolled using a repetitive cross rolling mill or the like so as to be perpendicular to the direction of the strip of the coil material. The brush 4 is blanked at a right angle to the direction of the coil material 13. The blank brush 4 is bent at a right angle as a boundary of a straight line B1-B2 shown in FIG. FIG. 1C is a perspective view of the brush 4 after the bending process. As a result, the bending line B1-B2 of the brush 4 is formed at right angles to the direction of the roll d of the rolling, so that cracks do not occur at the bent corners.

In the above description, the embodiment in which the coil material is rolled at a right angle to the strip direction by a repetitive cross rolling mill or the like has been described. However, the rolling direction of the rolling is an angle not parallel to the strip direction of the coil material. If so, the effect of the present invention can be obtained.

[0013]

According to the method of manufacturing a brush for a micromotor according to the present invention, the brush blank is formed at right angles to the direction of the strip of the coil material, thereby maximizing the material utilization rate and inexpensively. In addition, since the roll of the coil material of the raw material is perpendicular to the bending line of the brush, it is possible to provide a brush having a strength that does not cause cracking at the bent portion.

[Brief description of the drawings]

FIG. 1 is a blank and a bent view of a micromotor brush according to an embodiment of the present invention.

FIG. 2 is a perspective view of a brush of the micromotor according to the embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a conventional micromotor.

FIG. 4 is a diagram illustrating a blank and a bending of a conventional micromotor brush.

FIG. 5 is an explanatory view showing a blank and bending of a micromotor brush according to another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Bracket 3 Commutator 4 Brush 5a, 5b Bearing 6 Terminal 7 Shaft 8 Laminated iron core 9 Rotor coil 10 Magnet 11 Rotor 12 Thrust washer 13 Coil material a Noble metal bonding part b Bending corner part c Fixed part d Rolling roll of coil material direction

Claims (2)

[Claims] 1. A brush for a small motor formed of a conductive metal thin plate having a commutator slidable at a leading end thereof divided into a plurality of parts, wherein a roll direction does not coincide with a coil material direction. And small motor brush. 2. A brush structure for a small motor comprising a conductive metal thin plate having a noble metal adhered to a leading end on which a commutator slides, wherein the roll direction of the conductive metal plate is the same as that of the coil material. A method of manufacturing a brush for a small motor, wherein a longitudinal direction of the brush arm is blanked at right angles to a direction of a stripe of the conductive metal sheet.