Patent
Motor for an electric power steering apparatus
| العنوان: | Motor for an electric power steering apparatus |
|---|---|
| Patent Number: | 7,800,265 |
| تاريخ النشر: | September 21, 2010 |
| Appl. No: | 12/036515 |
| Application Filed: | February 25, 2008 |
| مستخلص: | A motor for an electric power steering apparatus can ensure an appropriate preload to an outer race of a rolling element bearing by adjusting the thickness of a spacer without replacement of a wave washer for a change in an axial dimension between a bottom surface of a bearing box and the bearing. The motor includes a rotor, a casing that receives the rotor and has the bearing box in which the bearing rotatably supporting a shaft of the rotor is received, an annular wave washer that is arranged between the bottom surface of the bearing box and the bearing, and applies a preload to the outer race of the bearing, and an annular spacer that is arranged between the bottom surface of the bearing box and the bearing so as to be in abutment with the wave washer for adjusting the preload applied to the outer race. |
| Inventors: | Nishikawa, Hideya (Chiyoda-ku, JP); Asao, Yoshihito (Chiyoda-ku, JP); Fujimoto, Kengo (Kengo, JP) |
| Assignees: | Mitsubishi Electric Corporation (Tokyo, JP) |
| Claim: | 1. A motor for an electric power steering apparatus, comprising: a rotor; a casing that receives said rotor therein and has a bearing box in which a rolling element bearing rotatably supporting a shaft of said rotor is received; a wave washer of an annular shape that is arranged between a bottom surface of said bearing box and said rolling element bearing, has a plurality of convex portions and concave portions that alternately undulate in a circumferential direction, and applies a preload to an outer race of said rolling element bearing; and a spacer of an annular shape that is arranged between said bottom surface of said bearing box and said rolling element bearing so as to be in abutment with said wave washer for adjusting said preload applied to said outer race, wherein said convex portions protrude in a direction towards said rotor,. wherein said spacer is formed of a resin, and has snap fit portions adapted to engage said wave washer, and wherein said snap fit portions engage an inner peripheral edge portion of said concave portions of said wave washer. |
| Claim: | 2. The motor for an electric power steering apparatus as set forth in claim 1 , wherein said spacer is provided with a retaining unit that is held in said bearing box. |
| Claim: | 3. The motor for an electric power steering apparatus as set forth in claim 2 , wherein said retaining unit is arranged on a diametrical line of said concave portions of said wave washer. |
| Claim: | 4. The motor for an electric power steering apparatus as set forth in claim 2 , wherein said retaining unit is arranged on diametrical lines of said convex portions of said wave washer. |
| Claim: | 5. A motor for an electric power steering apparatus, comprising: a rotor; a casing that receives said rotor therein and has a bearing box in which a rolling element bearing rotatably supporting a shaft of said rotor is received; a wave washer of an annular shape that is arranged between a bottom surface of said bearing box and said rolling element bearing, has a plurality of convex portions and concave portions that alternately undulate in a circumferential direction, and applies a preload to an outer race of said rolling element bearing; and a spacer of an annular shape that is arranged between said bottom surface of said bearing box and said rolling element bearing so as to be in abutment with said wave washer for adjusting said preload applied to said outer race, wherein said spacer is formed of a resin, and has snap fit portions adapted to engage said wave washer. |
| Claim: | 6. The motor for an electric power steering apparatus as set forth in claim 5 , wherein said spacer has holes formed at locations adjacent to said snap fit portions, respectively, so as to extend through and along said snap fit portions. |
| Claim: | 7. The motor for an electric power steering apparatus as set forth in claim 5 , wherein said spacer is released from its engagement with said wave washer by means of said snap fit portions in said bearing box. |
| Claim: | 8. The motor for an electric power steering apparatus as set forth in claim 7 , wherein said spacer is released from its engagement with said wave washer due to an enlarged inner diameter thereof resulting from deformation of said wave washer. |
| Claim: | 9. A motor for an electric power steering apparatus, comprising: a rotor; a casing that receives said rotor therein and has a bearing box in which a rolling element bearing rotatably supporting a shaft of said rotor is received; a wave washer of an annular shape that is arranged between a bottom surface of said bearing box and said rolling element bearing, has a plurality of convex portions and concave portions that alternately undulate in a circumferential direction, and applies a preload to an outer race of said rolling element bearing; and a spacer of an annular shape that is arranged between said bottom surface of said bearing box and said rolling element bearing so as to be in abutment with said wave washer for adjusting said preload applied to said outer race, wherein said spacer is provided with a retaining unit that is held in said bearing box, and wherein said spacer is formed of a resin, and said retaining unit comprises protrusions that are formed on the outer peripheral surface of said spacer, and are in pressure contact with an inner wall surface of said bearing box. |
| Claim: | 10. The motor for an electric power steering apparatus as set forth in claim 9 , wherein said wave washer and said spacer are formed of a spacer washer assembly of an integral structure. |
| Claim: | 11. The motor for an electric power steering apparatus as set forth in claim 9 , wherein said spacer has holes formed in the vicinity of said protrusions, respectively, so as to extend in a circumferential direction. |
| Claim: | 12. The motor for an electric power steering apparatus as set forth in claim 9 , wherein said spacer is formed on its inner peripheral edge portion with a wall that restricts the diametrical movement of said wave washer. |
| Current U.S. Class: | 310/90 |
| Patent References Cited: | 3516717 June 1970 Peterson 5719454 February 1998 Halsey et al. 7217106 May 2007 Tanaka et al. 2004/0134708 July 2004 Tanaka et al. 2006/0062505 March 2006 Hoefs 0469651 February 1992 59-95766 June 1984 61-101465 June 1986 07-039092 February 1995 08-149741 June 1996 2002-359945 December 2002 2004-210017 July 2004 2007112871 October 2007 |
| Other References: | Japanese Office Action dated Aug. 25, 2009. cited by other |
| Primary Examiner: | Le, Dang D |
| Attorney, Agent or Firm: | Sughrue Mion, PLLC |
| رقم الانضمام: | edspgr.07800265 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |