Electric motor
AssigneeJohnson Electric S.A.
InventorsRobin Warner, Siu Chun Tam
Life of this patent
Estimating the term…
Abstract
An electric motor 10 has a stator 14; a wound rotor 20, including a commutator 28; and brush gear for connecting the commutator to a source of electrical power. The brush gear has at least two cage brush assemblies 34. Each cage brush assembly 34 having a brush 40 for making sliding electrical contact with the commutator of the motor; a cage 50 for guiding the brush 40 along a path towards the commutator; and a spring 70 for resiliently urging the brush 40 along the path through the cage 50. The spring 70 is a constant force spring having two coiled end portions which engage the cage 50 at a commutator end portion. The cage 50 has two fingers about which the coiled end portions of the spring 70 locate.
Claims15
A cage brush assembly for an electric motor, comprising:
- a brush for making sliding electrical contact with a commutator of the motor;
- a cage for guiding the brush along a path, the cage having a first end portion adapted to be located in use adjacent to the commutator and a second end portion remote from the commutator;
- a spring for resiliently urging the brush along the path through the cage,
- wherein the spring is a constant force spring formed from a ribbon of resiliently deformable material having a middle portion which is substantially flat and two end portions which are coiled, the middle portion contacting an end of the brush, the cage having two fingers about which the coiled end portions of the spring locate respectively, the two fingers being located at the first end portion of the cage.
An electric motor, comprising:
- a stator;
- a wound rotor, including a shaft, rotor windings and a commutator;
- and
- brush gear for connecting the commutator to a source of electrical power, the brush gear having at least two cage brush assemblies, each cage brush assembly comprising:
- a brush for making sliding electrical contact with the commutator;
- a cage for guiding the brush along a path, the cage having a first end portion adapted to be located in use adjacent to the commutator and a second end portion remote from the commutator;
- a spring for resiliently urging the brush along the path through the cage,
- wherein the spring is a constant force spring formed from a ribbon of resiliently deformable material having a middle portion which is substantially flat and two end portions which are coiled, the middle portion contacting an end of the brush, the cage having two fingers about which the coiled end portions of the spring locate respectively, the two fingers being located at the first end portion of the cage.
Dependencies are inferred from the claim text.