Brush and commutator motor having brush device using the same

Claim 2

A brush having a wear portion which wears upon making contact with a commutator, almost all of the wear portion comprising at least two types of materials having different electric resistivities, and extending along a main current direction of the brush, comprising: a good conductive portion made of a first one of said at least two types of materials having a lowest electric resistivity, and said good conductive portion extending along the main current direction of said brush; a brush main portion made of a second one of said at least two types of materials having an electric resistivity higher than that of said good conductive portion, and said brush main portion extending along the main current direction of said brush; said brush main portion having a widthwise dimension larger than a respective widthwise dimension of said good conductive portion, as measured in a cross section of said brush perpendicular to the main current direction of said brush; said brush main portion having a proximal end surface, a commutator-side end surface which is opposed to said proximal end surface, and a hole therein which extends along the main current direction of said brush; said hole having a small cross sectional area portion arranged between a position near said commutator-side end surface and a position near said proximal end surface, and a large cross sectional area portion arranged between said position near said proximal end surface and said proximal end surface, said large cross sectional area portion having a larger cross sectional area than that of said small cross sectional area portion, said large cross sectional area portion being communicated at said position near said proximal end surface with said small cross sectional area portion, and said large cross sectional area portion having an opening in said proximal end surface; said good conductive portion being embedded in said hole from said large cross sectional area portion to said small cross sectional area portion; and a lead line made of a material having an electric resistivity lower than that of said second one of said materials for said brush main portion, and said lead line being inserted into and embedded in a part of said good conductive portion in said large cross sectional area portion of said hole of said brush main portion via said opening of said large cross sectional area portion.

Claim 3

A brush according to claim 1, wherein said good conductive portion is formed in a shape corresponding to an internal shape of said hole, prior to being embedded in said hole of said brush main portion, and is thereafter inserted in said hole via said opening of said large cross sectional area portion of said hole so as to be fitted and embedded in said hole.

Claim 4

A brush according to claim 1, wherein said large cross sectional area portion of said hole of said brush main portion has a step extending in a radial direction of said hole at said position near said proximal end surface.

Claim 5

A brush according to claim 1, wherein said hole of said brush main portion further has an air gap arranged between said position near said commutator-side end surface and said commutator-side end surface, said air gap being adjacent to said small cross sectional area portion, and said air gap opening in said commutator-side end surface.

Claim 6

A brush according to claim 4, wherein said large cross sectional area portion of said hole of said brush main portion has a step extending in a radial direction of said hole at said position near said proximal end surface.

Claim 7

A brush according to claim 1, wherein said good conductive portion is made of an electric conductive powder filled in said hole via an opening of said large cross sectional area portion, and wherein said powder is thereafter stamped so as to be hardened.

Claim 8

A brush according to claim 6, wherein said large cross sectional area portion of said hole of said brush main portion has a step extending in a radial direction of said hole at said position near said proximal end surface.

Claim 9

A brush according to claim 6, wherein said hole of said brush main portion further has an air gap arranged between said position near said commutator-side end surface and said commutator-side end surface, said air gap being adjacent to said small cross sectional area portion, and said air gap opening in said commutator-side end surface.

Claim 10

A brush according to claim 8, wherein said large cross sectional area portion of said hole of said brush main portion has a step extending in a radial direction of said hole at said position near said proximal end surface.

Claim 11

A commutator motor, comprising: a stator; a motor case containing said stator; a rotor having a rotor shaft and a commutator fixed to the rotor shaft, said rotor being arranged inside said stator in said motor case and being rotatably supported by said motor case; and a brush device having a brush which is brought into contact with said commutator of said rotor and is supported by said motor case, almost all of a portion of said brush, which wears upon making contact with said commutator, comprising at least two types of materials having different electric resistivities, and extending along a main current direction of said brush; said brush comprising: a good conductive portion made of a first one of said at least two types of materials having a lowest electric resistivity, and said good conductive portion extending along said main current direction of said brush; a brush main portion made of a second one of said at least two types of materials having an electric resistivity higher than that of said good conductive portion, and said brush main portion extending along said main current direction of said brush; said brush main portion having a widthwise dimension larger than a respective widthwise dimension of said good conductive portion, as measured in a cross section of said brush perpendicular to said main current direction of said brush; said brush main portion having a proximal end surface, a commutator-side end surface which is opposed to said proximal end surface, and a hole therein which extends along said main current direction of said brush; said hole having a small cross sectional area portion arranged between a position near said commutator-side end surface and a position near said proximal end surface, and a large cross sectional area portion arranged between said position near said proximal end surface and the proximal end surface, said large cross sectional area portion having a larger cross sectional area than that of said small cross sectional area portion, said large cross sectional area portion being communicated at said position near said proximal end surface with said small cross sectional area portion, and said large cross sectional portion having an opening in said proximal end surface; said good conductive portion being embedded in said hole from said large cross sectional area portion to said small cross sectional area portion; and a lead line made of a material having an electric resistivity lower than that of said second one of said materials a part of said good conductive portion in for said brush main portion, and said lead line being inserted into and embedded in said large cross sectional area portion of said hole of said brush main portion via said opening of said large cross sectional area portion.

Claim 12

A commutator motor, comprising: a stator; a motor case containing said stator; a rotor having a rotor shaft and a commutator fixed to the rotor shaft, said rotor being arranged inside said stator in said motor case and being rotatably supported by said motor case; and a brush device having a brush which is brought into contact with said commutator of said rotor and is supported by said motor case, almost all of a portion of said brush, which wears upon making contact with said commutator, comprising at least two types of materials having different electric resistivities, and extending along a main current direction of said brush; said brush comprising: a good conductive portion made of a first one of said at least two types of materials having a lowest electric resistivity, and said good conductive portion extending along said main current direction of said brush; a brush main portion made of a second one of said at least two types of materials having an electric resistivity higher than that of said good conductive portion, and said brush main portion extending along said main current direction of said brush; said brush main portion having a widthwise dimension larger than a respective widthwise dimension of said good conductive portion, as measured in a cross section of said brush perpendicular to said main current direction of said brush; said brush main portion having a proximal end surface, a commutator-side end surface which is opposed to said proximal end surface, and a hole therein which extends along said main current direction of said brush; said hole having a small cross sectional area portion arranged between a position near said commutator-side end surface and a position near said proximal end surface, and a large cross sectional area portion arranged between said position near said proximal end surface and the proximal end surface, said large cross sectional area portion having a larger cross sectional area than that of said small cross sectional area portion, said large cross sectional area portion being communicated at said position near said proximal end surface with said small cross sectional area portion, and said large cross sectional portion having an opening in said proximal end surface; said good conductive portion being embedded in said hole from said large cross sectional area portion to said small cross sectional area portion; and a lead line made of a material having an electric resistivity lower than that of said second one of said materials a part of said good conductive portion in for said brush main portion, and said lead line being inserted into and embedded in said large cross sectional area portion of said hole of said brush main portion via said opening of said large cross sectional area portion.

Claim 13

A commutator motor according to claim 10, wherein said good conductive portion is formed in a shape corresponding to an internal shape of said hole, prior to being embedded in said hole of said brush main portion, and is thereafter inserted in said hole via said opening of said large cross sectional area of said hole so as to be fitted and embedded in said hole.

Claim 14

A commutator motor according to claim 11, wherein said large cross sectional area portion of said hole of said brush main portion has a step extending in a radial direction of said hole at said position near said proximal end surface.

Claim 15

A commutator motor according to claim 10, wherein said hole of said brush main portion further has an air gap arranged between said position near said commutator-side end surface and said commutator-side end surface, said air gap being adjacent to said small cross sectional area portion, and said air gap opening in said commutator-side end surface.

Claim 16

A commutator motor according to claim 13, wherein said large cross sectional area portion of said hole of said brush main portion has a step extending in a radial direction of said hole at said position near said proximal end surface.

Claim 17

A commutator motor according to claim 10, wherein said good conductive portion is made of an electric conductive powder filled in said hole via an opening of said large cross sectional area portion, and wherein powder is thereafter stamped so as to be hardened.

Claim 18

A commutator motor according to claim 15, wherein said large cross sectional area portion of said hole of said brush main portion has a step extending in a radial direction of said hole at said position near said proximal end surface.

Claim 19

A commutator motor according to claim 15, wherein said hole of said brush main portion further has an air gap arranged between said position near said commutator-side end surface and said commutator-side end surface, said air gap being adjacent to said small cross sectional area portion, and said air gap opening in said commutator-side end surface.

Claim 20

A commutator motor according to claim 17, wherein said large cross sectional area portion of said hole of said brush main portion has a step extending in a radial direction of said hole at said position near said proximal end surface.