JPH0523778U - Small motor brush - Google Patents

Abstract

(57) [Abstract] [Purpose] The problem that the contact between the brush and the commutator becomes unstable during high-speed rotation in a small motor that has a brush that is bent in an approximately L-shape in the longitudinal direction used in various electric devices. An object of the present invention is to provide a brush for a small motor that is small and has stable characteristics at high speed rotation. [Structure] A brush of a small motor in which a brush body bent in the longitudinal direction into an approximate L shape is fixed to a terminal plate.
The brush width of the portion is made larger than the brush width of the boundary portion between the brush body 11 and the brush piece 13.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brush of a small motor used as a drive source for video tape recorders, tape loading such as DAT, and other various household appliances and industrial appliances.

[0002]

[Prior Art]

 In recent years, small motors, as represented by video movies, have been required to be smaller and lighter as the equipment becomes smaller and lighter, and the market demands that the outer diameter of the motor be φ10 mm or less.

A conventional brush for a small motor will be described below. FIG. 4 shows a conventional brush of a small motor. In FIG. 4, 41 is a brush main body made of a conductive metal thin plate which is bent in a substantially L shape in the longitudinal direction, and 42 is extended to one end of the brush main body 41 to fix the terminal plate 2 made of a conductive metal. The terminal plate fixing portion 43 for extending from the other end of the brush main body portion 41 is formed from a plurality of slit-shaped portions that are in sliding contact with a commutator (not shown) of the motor and conduct electricity to the commutator. The brush pieces 3 and 3 are anti-vibration rubbers for preventing the brush piece 43 from vibrating in the radial direction of the commutator. The brush widths of the brush main body 41 and the terminal plate fixing portion 42 are the brush main body. It has the same configuration as the brush width of the boundary portion XX between the portion 41 and the brush piece 43.

[0004]

[Problems to be solved by the device]

 However, with the above-mentioned conventional configuration, in the case of a small motor with an outer diameter of φ10 mm, only about 4 mm can be taken from the sliding contact between the brush and the commutator to the bending R of the brush. Generally, the thickness of the brush is about 0.07 mm, and the width of the brush piece is about 0.2 mm, which is generally three. Compared to a motor with an outer diameter of about 20 mm, the strength of the brush is very high. It's getting weaker.

For this reason, when the rotation speed is about 20000 rpm, the pulsation of the sliding resistance between the commutator and the brush causes the brush to pulsate in the longitudinal direction, which increases the pulsation frequency and the commutation of the brush. There is a problem that the child cannot follow the contact and the contact becomes unstable, resulting in an intermittent current waveform as shown in Fig. 5, and the rotation speed decreases and the desired characteristics cannot be obtained.

The present invention solves the above-mentioned conventional problems, and an object thereof is to obtain a brush for a small motor having stable characteristics even at high speed rotation.

[0007]

[Means for Solving the Problems]

 In order to achieve this object, the brush of the small motor of the present invention is configured such that the brush width of the approximately L-shaped bend R portion of the brush main body is wider than the brush width at the boundary between the brush main body and the brush piece. have.

[0008]

[Action]

 With this configuration, the strength of the brush main body is improved from the terminal plate fixing part of the brush to the vicinity of the boundary with the brush piece through the bending R part, and at the time of high speed rotation, pulsation of the sliding resistance of the commutator and the brush causes Even if a force that pulsates in the longitudinal direction acts on the brush, the brush rarely pulsates in the longitudinal direction, so the contact between the commutator and the brush becomes stable, and stable motor characteristics can be obtained.

[0009]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing a brush of a small motor in a first embodiment of the present invention, and FIG. 2 is an operation explanatory diagram thereof. In FIG. 1 and FIG. 2, 11 is a brush main body made of a conductive metal thin plate bent in a substantially L shape in the longitudinal direction, and 12 is a terminal plate 2 made of a conductive metal and extending at one end of the brush main body 11. A terminal fixing portion 13 for fixing the motor is provided at the other end of the brush main body 11 so as to be narrower than the brush main body 11 and slidably contacts a commutator (not shown) of the motor to apply electricity to the commutator. A plurality of brush pieces 3 formed in a conductive slit shape are vibration-proof rubbers for preventing the brush pieces 13 from vibrating in the radial direction of the commutator. Reference numeral 4 is a pulsating force due to sliding resistance between the commutator and the brush (not shown), and 5 is a displacement amount in the longitudinal direction of the brush.

The operation of the brush of the small motor configured as described above will be described with reference to FIG. First, when the pulsating force 4 is applied to the brush main body 11 by the pulsation of the sliding resistance between the brush and the commutator, the brush main body 11 pulsates about the terminal plate 2 in the longitudinal direction by the displacement amount 5. However, since the brush width of the bending R portion of the brush main body 11 is wider than that of the brush piece 13 boundary portion XX, the strength from the terminal plate fixing portion 12 to the bending R portion is increased, and the pulsation force 4 is increased. Even if added, the displacement amount 5 in the longitudinal direction of the brush is small. Therefore, the contact between the brush and the commutator is stable. FIG. 6 shows the motor current waveform in this case.

Second Embodiment A second embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, reference numeral 31 is a brush main body portion, 32 is a terminal plate fixing portion, 33 is a brush piece, 2 is an end plate, 3 is a vibration-proof rubber, and the above is the same as the configuration of FIG. The difference from the configuration of FIG. 1 is that there is a step on both sides of the brush at the boundary XX between the brush main body 31 and the brush piece 33. Even in this case, the displacement amount in the longitudinal direction of the brush due to the pulsation of the sliding resistance between the commutator (not shown) and the brush piece can be suppressed to a small value, and the contact between the brush and the rectifier is stabilized.

[0014]

[Effect of the device]

 As described above, according to the present invention, the brush width at the bending R portion of the brush main body is made larger than the brush width at the boundary between the brush main body and the brush piece, so that the brush and the commutation are stable even at high speed rotation. It is possible to realize an excellent brush for a small motor that can obtain contact with the child and obtain stable motor characteristics.

[Brief description of drawings]

FIG. 1 is a perspective view of a brush of a small motor according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the brush of the small motor according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a brush of a small motor according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a conventional small motor brush.

FIG. 5 is a diagram showing a current waveform of a conventional small motor at high speed.

FIG. 6 is a diagram showing a current waveform at a high speed of the small motor of the present invention.

[Explanation of symbols]

 2 Terminal plate 3 Anti-vibration rubber 4 Pulsating power 5 Displacement amount 11, 31, 41 Brush main body part 12, 32, 42 Terminal plate fixing part 13, 33, 43 Brush piece

Claims (1)

[Scope of utility model registration request] 1. A terminal plate fixing portion having a terminal plate fixed to one end, a plurality of brush pieces provided in a slit shape in sliding contact with a commutator of a motor at the other end, and a brush main body portion at an intermediate portion. In a brush of a small motor bent in an approximately L-shape at the brush body, the brush width at the approximate L-shaped bend R portion of the brush body is the brush width at the boundary between the brush body and the brush piece. A brush for a small motor characterized by being made wider.