Structure for slip ring and brush of wound rotor synchronous motor

1. A structure for a slip ring and a brush of a wound rotor synchronous motor (WRSM), the structure comprising:

an inner slip ring combined with a rotation shaft of a motor;

a brush disposed at a circumference of the inner slip ring, wherein the brush is formed in a cylindrical shape, and a circumferential surface of the brush is form to have a plurality of ripple-shaped wrinkles contacting an outer circumferential surface of the inner slip ring formed therein;

an outer slip ring disposed at a circumference of the brush and making in contact with the plurality of the ripple-shaped wrinkles of the brush; and

a holder that supports the outer slip ring.

2. The structure of claim 1 , wherein the ripple-shaped wrinkles of the brush are arranged in a circumferential direction at equal intervals and are in contact with the outer circumferential surface of the inner slip ring and an inner circumferential surface of the outer slip ring, respectively.

3. The structure of claim 1 , wherein each of a plurality of inner slip rings, a plurality of brushes, and a plurality of outer slip rings are arranged in a lengthwise direction of the rotation shaft.

4. The structure of claim 3 , wherein the plurality of brushes are arranged on the rotation shaft in a state in which the ripple-shaped wrinkles of the brushes are disposed not to cross one another.

5. The structure of claim 1 , wherein accommodation grooves in which the inner slip ring, the brush and the outer slip ring are accommodated, are formed in the holder.

6. The structure of claim 5 , wherein foreign substance discharge ports perforated in an axial direction to communicate with the accommodation grooves are formed in the holder.

7. The structure of claim 6 , wherein a fan that induces forcible discharge of foreign substances through the foreign substance discharge ports is installed at the motor.

8. The structure of claim 1 , wherein the holder is press-fitted into and combined with the motor.

9. The structure of claim 8 , wherein pin grooves into which pins are press-fitted, are formed in the holder so that a position of the holder press-fitted into the motor is fixed.

10. The structure of claim 9 , wherein the pin grooves are formed in an outer surface of the holder to have semicircular cross-sections.

11. The structure of claim 1 , wherein magnetic bodies are installed between the inner slip ring and the brush, and a sensor for detecting positions of the magnetic bodies is installed at the holder.

12. The structure of claim 11 , wherein the magnetic bodies are formed by injecting moldable magnetic materials between the inner slip ring and the brush.

13. The structure of claim 11 , wherein the sensor is a hall sensor.

14. The structure of claim 11 , further comprising wires for applying a current to the outer slip ring, wherein the wires are integrally installed in the holder together with wires for supplying power to the sensor.

15. A structure for a slip ring and a brush of a wound rotor synchronous motor (WRSM), the structure comprising:

an inner slip ring combined with a rotation shaft of a motor;

a brush disposed at a circumference of the inner slip ring, wherein the brush is formed in a cylindrical shape, and a circumferential surface of the brush is form to have a plurality of ripple-shaped wrinkles contacting an outer circumferential surface of the inner slip ring formed therein;

an outer slip ring disposed at a circumference of the brush and making in contact with the plurality of the ripple-shaped wrinkles of the brush;

wires for applying a current to the outer slip ring; and

a holder that supports the outer slip ring.