Patent ID: 8648515

Claim:
A brush for making electrical contact with a commutator of an electric motor, the commutator having an insulating base, and a plurality of segments circumferentially spaced on an outer surface of the insulating base with a gap between adjacent segments, the brush comprising: a first end surface; a second end surface opposite to the first end surface; and a contact surface extending at least partially between the first and second end surfaces, configured to make sliding contact with a cylindrical circumferential surface of the commutator, and having a circumferential width smaller than total circumferential width of one said segment and one said gap of the commutator so that the contact surface makes contact with at most two adjacent segments of the commutator at any time; wherein the extending direction of the contact surface is inclined relative to the axial direction of the commutator, the contact surface is V-shaped when viewed in the extending direction thereof, a middle portion of the contact surface is concaved relative to two opposite side portions of the contact surface; and the initial contact between the contact surface of the brush and the surface of the commutator are only two point contacts.