Rotor assembly with balancing member

• US 20070194637A1
• Filed: 09/17/2004
• Published: 08/23/2007
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Original Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Inventors: Crossley, Peter, Childe, Matthew
• Granted Patent: US 7,786,628 B2
• Time in Patent Office: Days
• US Class Current: 310/51
• CPC Class Codes: A47L 5/22 with rotary fans
• CPC Class Codes: F04D 29/662 Balancing of rotors compensating unbalance G01M1/36
• CPC Class Codes: F16C 19/54 Systems consisting of a plurality of bearings with rolling friction spindle bearings F16C35/08
• CPC Class Codes: F16C 2314/00 Personal or domestic articles, e.g. household appliances such as washing machines, dryers in general A41 - A47
• CPC Class Codes: F16C 2360/44 Centrifugal pumps in general F04D
• CPC Class Codes: F16C 2380/26 Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators in general H02K
• CPC Class Codes: F16C 27/066 Ball or roller bearings
• CPC Class Codes: F16C 33/723 Shaft end sealing means, e.g. cup-shaped caps or covers
• CPC Class Codes: F16C 35/077 between housing and outer race ring
• CPC Class Codes: H02K 15/16 Centering rotors within the stator; Balancing rotors
• CPC Class Codes: H02K 15/165 Balancing the rotor
• CPC Class Codes: H02K 29/10 using light effect devices
• CPC Class Codes: H02K 5/1732 radially supporting the rotary shaft at both ends of the rotor H02K5/1737 takes precedence
• CPC Class Codes: H02K 5/24 specially adapted for suppression or reduction of noise or vibrations
• CPC Class Codes: H02K 7/04 Balancing means
• CPC Class Codes: H02K 7/14 Structural association with mechanical loads, e.g. with hand-held machine tools or fans with fan or impeller for cooling the machine H02K9/06
• CPC Class Codes: H02K 9/06 with fans or impellers driven by the machine shaft

Abstract

A rotor assembly for an electronic machine such as a motor includes a rotor on a shaft having a bearing at each end portion, the bearings being arranged to rotatably support the rotor and shaft. The assembly further includes a balancing member, from which material may be removed for balancing the rotor assembly. The balancing member is located in a predetermined position and orientation with respect to the rotor. The balancing member includes an encoder disk, arranged to permit positioning of the rotor with respect to a stator. The provision of a balancing member having an integral encoder disk facilitates the manufacture of the rotor assembly. As the balancing member is located in a predetermined position, the encoder automatically assumes a predetermined position and hence the position of the rotor can be determined with certainty.

Claims

1. A rotor assembly comprising a shaft carrying a rotor and a balancing member from which material is selectively removable and which comprises an encoder member, the balancing member being located in a predetermined position with respect to the rotor.

2. A rotor assembly as claimed in claim 1, wherein the rotor has a plurality of poles and the balancing member has at least one lug located between adjacent poles.

3. A rotor assembly as claimed in claim 1 or 2, wherein the encoder member comprises a disk having at least one aperture.

4. A rotor assembly as claimed in claim 1 or 2, wherein the balancing member comprises a main body and a sleeve, the encoder member being located on the sleeve.

5. A rotor assembly as claimed in claim 4, wherein the main body is located adjacent one end portion of the rotor.

6. A rotor assembly as claimed in claim 5, further comprising a second balancing member located adjacent the other end portion of the rotor.

7. A rotor assembly as claimed in claim 1 or 2, wherein each balancing member is made of a plastic material.

9. An electrical machine comprising the rotor assembly as claimed in claim 1 or 2.

10. An electrical machine as claimed in claim 9, further comprising a stator in which the rotor assembly is arranged to rotate, a light source and an optical detector, the encoder member being arranged to interrupt intermittently light between the source and detector as the rotor assembly rotates.

11. An electrical machine as claimed in claim 10, further comprising electrical windings on the stator and a controller arranged to energize the windings in dependence on signals from the detector.

12. An electrical machine as claimed in claim 11 in the form of a high-speed motor.

15. A cleaning appliance comprising the electrical machine as claimed in claim 11.

23. A rotor assembly as claimed in claim 1 or 2, wherein the encoder member is formed integrally with the balancing member as one piece.

24. An electrical machine as claimed in claim 23 in the form of a high-speed motor.

25. A cleaning appliance comprising the electrical machine as claimed in claim 24.

8. (canceled)

13-14. -14. (canceled)

16. (canceled)

17. A balancing member for a rotor assembly comprising an encoder member formed integrally with the balancing member and a locating device arranged to locate the balancing member on a shaft in a predetermined position with respect to a rotor.

18. A balancing member as claimed in claim 17, wherein the locating device comprises a lug arranged to locate in a region between rotor poles.

19. (canceled)

20. A method of manufacture of a rotor assembly comprising:

assembling a rotor on a shaft,

introducing a balancing member comprising an encoder member integrally formed with the balancing member onto the shaft, and

arranging the balancing member to occupy a predetermined position with respect to the rotor.

21. A method as claimed in claim 20, further comprising selectively removing material from the balancing member in order to balance the rotor assembly.

22. (canceled)