Motor having shaft-grounding arrangement

• US 20010017495A1
• Filed: 02/21/2001
• Published: 08/30/2001
• Est. Priority Date: 02/29/2000
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: ASMO Company Limited (DENSO Corporation)
• Inventors: Gonda, Shuuichi, Sato, Toshihiro
• Granted Patent: US 6,608,410 B2
• Time in Patent Office: Days
• US Class Current: 310/67R
• CPC Class Codes: H02K 11/40 Structural association with grounding devices
• CPC Class Codes: H02K 23/04 having permanent magnet excitation
• CPC Class Codes: H02K 5/15 Mounting arrangements for bearing-shields or end plates
• CPC Class Codes: H02K 5/161 radially supporting the rotary shaft at both ends of the rotor H02K5/165, H02K5/167, H02K5/173 take precedence

Abstract

A DC motor has a conductive case and an arrangement for electrically connecting the shaft and case of the DC motor that is grounded. The arrangement includes a conductive member and a pressing member that presses the conductive member against the shaft, thereby grounding the shaft.

Claims

1. A motor comprising:

a rotor;

an armature coil;

a conductive case for accommodating said rotor;

a member for grounding said case;

a shaft having a portion extending outward from said case;

a bearing fixed to said case for rotatably supporting said shaft;

means, including a conductive member in contact with said shaft and said case, for pressing said conducting member between said shaft and said case.

2. The motor as claimed in

claim 1

, wherein

said means comprises a resilient contact member integrated with said case.

3. The motor as claimed in

claim 2

, wherein

said means comprises a parallel portion extending in the direction in parallel with said shaft and a slant portion slanting toward the center of said shaft.

4. The motor as claimed in

claim 3

, further comprising a housing for fixing said case, wherein

said means further comprises a disk portion held between said case and said housing.

5. The motor as claimed in

claim 4

, wherein

said ring portion comprises a plurality of slanted spring members.

6. The motor as claimed in

claim 3

, wherein

said motor further comprises a noise suppressing circuit having a pair of noise suppressing coils connected in series with said armature coil and a capacitor connected in parallel with said pair of noise suppressing coils.

7. The motor as claimed in

claim 4

, wherein

said motor further comprises a noise suppressing circuit having a pair of noise suppressing coils connected in series with said armature coil and a capacitor connected in parallel with said pair of noise suppressing coils.

8. The motor as claimed in

claim 1

, wherein

said means comprises a resinous bearing holder for holding said bearing,

said bearing has a spherical outer surface, and

said bearing holder has a spherical inner surface to which said bearing is fitted.

9. The motor as claimed in

claim 1

, wherein

said means comprises a conductive bearing holder fixed to said case and having a resilient contact member in contact with said bearing.

10. The motor as claimed in

claim 9

, further comprising a magnetic core and a permanent magnet disposed opposite said magnetic core to magnetically link with each other, wherein

said means comprises said magnetic core and said permanent magnet disposed to generate a magnetic force to press said contact member against said bearing.

11. The motor as claimed in

claim 1

, wherein

said means comprises said case as said contact member.

12. The motor as claimed in

claim 11

, further comprising a magnetic core and a permanent magnet disposed opposite said magnetic core to magnetically link with each other, wherein

said means comprises said magnetic core and said permanent magnet disposed to generate a magnetic force to press said contact member against said bearing.

13. The motor as claimed in

claim 1

, wherein

said bearing is directly fixed to said case,

said shaft has a collar, and

said means comprises a spring washer held between said bearing and said collar.

14. The motor as claimed in

claim 13

, further comprising a bearing-holding washer having a resilient projecting member, wherein

said means comprises resilient-projecting member.

15. The motor as claimed in

claim 13

, further comprising a housing for fixing said case, wherein

said means further comprises a disk portion held between said case and said housing.

16. The motor as claimed in

claim 15

, wherein

said disk portion comprises a plurality of slanted spring members.

17. The motor as claimed in

claim 1

, further comprising a conductive shield member disposed between said shaft and said case, wherein

said means comprises said shield member.

18. The motor as claimed in

claim 1

, wherein

said motor further comprises a noise suppressing circuit having a pair of noise suppressing coils connected in series with said armature coil and a capacitor connected in parallel with said pair of noise suppressing coils.