Copper-graphite composite brush for motor

Abstract

The invention discloses a low-cost and high-performance copper-graphite composite electric brush. The brush is first stirred and mixed from graphite powder, copper powder, silicon powder and asphalt binder raw materials through the traditional powder metallurgy copper-graphite brush process. It is made by a post-pressing and re-sintering process. The process and material cost of the invention are low, the brush performance is significantly improved, and it can meet the usage requirements of brushes for commutators and collector ring motors.

Description

Technical field

[0001] The invention belongs to the field of electrical contact materials, and specifically relates to a copper-graphite composite material brush for motors. Background technique

[0002] Copper-graphite composite brushes are mainly used in collector rings and commutators of low-voltage DC motors, AC asynchronous motors, automobile and motorcycle starters and synchronous motors in the automotive, aviation, and electrical industries. The matrix copper and graphite phases in the copper-graphite composite brush have the requirements of conducting electricity and improving wear resistance and service life respectively. However, using the traditional powder metallurgy process, there is a contradiction between the two, that is, by increasing the copper content in the brush, The requirements for electrical conductivity can be increased, but the wear resistance and service life are reduced, and vice versa. In order to obtain good electrical properties and wear resis...

Examples

Embodiment 1

[0013] Example 1: 50 parts of graphite powder with a particle size of less than 300 meshes, 25 parts of graphite powder with a purity of 99.5%, and 0.4 parts of electrolytic copper powder with a particle size of less than 400 meshes, with a purity of 95%, and a particle size of less than 300 mesh silicon powder and 7 parts of asphalt powder with a particle size of less than 400 mesh are mixed uniformly, and then uniformly mixed according to the traditional powder metallurgy manufacturing copper graphite electric brush process, and then pressed and sintered. After testing, its resistivity is 0.41μΩ·m, Rockwell hardness is 96.8, peripheral speed is 15m / s, wear rate is 0.06mm / 50h, friction coefficient is 0.20, and the total voltage drop of a pair of brushes is 1.92V. Rated current density is 15A / cm 2 .

Embodiment 2

[0014] Example 2: According to mass parts, 80 parts of graphite powder with a particle size of less than 300 mesh, 50 parts with a purity of 99.5%, a particle size of less than 400 mesh, 1.5 parts with a purity of 95%, and a particle size of less than 300 mesh silicon powder and 18 parts of asphalt powder with a particle size of less than 400 mesh are mixed uniformly, and then uniformly mixed according to the traditional powder metallurgy manufacturing copper graphite electric brush process, pressed and sintered. After testing, its resistivity is 0.09μΩ·m, Rockwell hardness is 90, peripheral speed is 15m / s, wear rate is 0.06mm / 50h, friction coefficient is 0.21, and the total voltage drop of a pair of brushes is 0.5V. Rated current density is 20A / cm 2 .

Embodiment 3

[0015] Example 3: According to the number of parts by mass, 60 parts of graphite powder with a particle size of less than 300 mesh, 35 parts with a purity of 99.5%, a particle size of less than 400 mesh, 1.0 part with a purity of 95%, and a particle size of less than 300 mesh silicon powder and 13 parts of asphalt powder with a particle size of less than 400 mesh are mixed uniformly, and then uniformly mixed according to the traditional powder metallurgy manufacturing copper-graphite electric brush process, pressed and sintered. After testing, its resistivity is 8.9μΩ·m, Rockwell hardness is 69.2, peripheral speed is 15m / s, wear rate is 0.03mm / 50h, friction coefficient is 0.20, and the total voltage drop of a pair of brushes is 2.8V. Rated current density is 15A / cm 2 .

Technical field

[0001] The invention belongs to the field of electrical contact materials, and specifically relates to a copper-graphite composite material brush for motors. Background technique

[0002] Copper-graphite composite brushes are mainly used in collector rings and commutators of low-voltage DC motors, AC asynchronous motors, automobile and motorcycle starters and synchronous motors in the automotive, aviation, and electrical industries. The matrix copper and graphite phases in the copper-graphite composite brush have the requirements of conducting electricity and improving wear resistance and service life respectively. However, using the traditional powder metallurgy process, there is a contradiction between the two, that is, by increasing the copper content in the brush, The requirements for electrical conductivity can be increased, but the wear resistance and service life are reduced, and vice versa. In order to obtain good electrical properties and wear resis...

Examples

Embodiment 1

[0013] Example 1: 50 parts of graphite powder with a particle size of less than 300 meshes, 25 parts of graphite powder with a purity of 99.5%, and 0.4 parts of electrolytic copper powder with a particle size of less than 400 meshes, with a purity of 95%, and a particle size of less than 300 mesh silicon powder and 7 parts of asphalt powder with a particle size of less than 400 mesh are mixed uniformly, and then uniformly mixed according to the traditional powder metallurgy manufacturing copper graphite electric brush process, and then pressed and sintered. After testing, its resistivity is 0.41μΩ·m, Rockwell hardness is 96.8, peripheral speed is 15m / s, wear rate is 0.06mm / 50h, friction coefficient is 0.20, and the total voltage drop of a pair of brushes is 1.92V. Rated current density is 15A / cm 2 .

Embodiment 2

[0014] Example 2: According to mass parts, 80 parts of graphite powder with a particle size of less than 300 mesh, 50 parts with a purity of 99.5%, a particle size of less than 400 mesh, 1.5 parts with a purity of 95%, and a particle size of less than 300 mesh silicon powder and 18 parts of asphalt powder with a particle size of less than 400 mesh are mixed uniformly, and then uniformly mixed according to the traditional powder metallurgy manufacturing copper graphite electric brush process, pressed and sintered. After testing, its resistivity is 0.09μΩ·m, Rockwell hardness is 90, peripheral speed is 15m / s, wear rate is 0.06mm / 50h, friction coefficient is 0.21, and the total voltage drop of a pair of brushes is 0.5V. Rated current density is 20A / cm 2 .

Embodiment 3

[0015] Example 3: According to the number of parts by mass, 60 parts of graphite powder with a particle size of less than 300 mesh, 35 parts with a purity of 99.5%, a particle size of less than 400 mesh, 1.0 part with a purity of 95%, and a particle size of less than 300 mesh silicon powder and 13 parts of asphalt powder with a particle size of less than 400 mesh are mixed uniformly, and then uniformly mixed according to the traditional powder metallurgy manufacturing copper-graphite electric brush process, pressed and sintered. After testing, its resistivity is 8.9μΩ·m, Rockwell hardness is 69.2, peripheral speed is 15m / s, wear rate is 0.03mm / 50h, friction coefficient is 0.20, and the total voltage drop of a pair of brushes is 2.8V. Rated current density is 15A / cm 2 .

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