Power steering apparatus

• US 6,467,567 B2
• Filed: 11/29/2000
• Issued: 10/22/2002
• Est. Priority Date: 11/30/1999
• Status: Active Grant

• Current Assignee: Koyo Seiko Co., Ltd. (Toyota Motor Corporation)
• Original Assignee: Koyo Seiko Co., Ltd. (Toyota Motor Corporation)
• Inventors: Ogushi, Kouji, Deyama, Takefumi, Kobayashi, Masanori, Murakami, Hiroaki, Tsutsui, Takashi, Kitami, Etsuro, Tsutsui, Teruo
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): LUM VANNUCCI, LEE SIN YEE
• Application Number:
  US09/725,001
• Publication Number:
  US 20010001932A1
• Time in Patent Office: 692 Days
• Field of Search: 180/443-447, 180/428, 743/88.PS, 744/22
• US Class Current: 180/444
• CPC Class Codes: B62D 3/12 of rack-and-pinion type
• CPC Class Codes: B62D 5/00 Power-assisted or power-driven steering for non-deflectable wheels B62D11/00; fluid-pressure servomotors in general F15B

Abstract

When a steering wheel is relatively quickly turned at the time of parking, before a first stopper mechanism located between an input shaft and an output shaft is operated, an elastic member 47 attached to a movement end of a rack shaft 13 comes into contact with a rack stopper 39 of a rack housing 14, thereby absorbing the impact at the time of steering at parking. That is, the strike speed when contact portions of the first stopper mechanism are brought into contact with each other, is slowed down. Accordingly, the uncomfortable noise due to the strike sound is not given to the driver.

Claims

1. A power steering apparatus in which a steering assisting force for driving a steering mechanism is generated in accordance with relative displacement between an input shaft and an output shaft connected to each other through a torsion bar, the power steering apparatus comprising:

a first stopper mechanism located between the input shaft and the output shaft, the first stopper mechanism including a pair of mating contact portions contactable with each other to regulate a relative rotation between the input shaft and the output shaft within a predetermined relative rotation range; and

a second stopper mechanism provided at each end of the steering mechanism, the second stopper mechanism including a pair of mating contact members contactable with each other to regulate a movement of a sliding shaft in the steering mechanism,

wherein at least one of the contact members include an elastic member, and when the sliding shaft is moved to a stroke end, the second stopper mechanism is operated and thereafter the first stopper mechanism is operated,

wherein the first stopper mechanism is located within a column in a car room.

2. The power steering apparatus according to claim 1, further comprising:

a motor for generating the steering assistant force for driving the steering mechanism in accordance with a relative displacement between an input shaft and an output shaft.

3. The power steering apparatus according to claim 1, wherein when the sliding shaft is moved to the stroke end, the contact members in the second stopper mechanism are brought into contact with each other prior to contact between the contact portions in the first stopper mechanism.

4. The power steering apparatus according to claim 1, wherein when the sliding shaft is moved to the stroke end, and when the contact members in the second stopper mechanism contact with each other within an elastic range of the elastic member, the contact portions in the first stopper mechanism are brought into contact with each other.

5. The apparatus of claim 1, wherein the second stopper mechanism includes a ring shaped holder abutting against a joint of a rack shaft and an elastic member positioned on the ring shaped holder and opposing a rack stopper on a rack housing.

6. The apparatus of claim 5, wherein the ring shaped holder includes a large diameter portion having an end surface abutting the joint, a reduced diameter portion receiving the elastic member and an annular step portion between the large diameter portion and the reduced diameter portion.

7. The apparatus of claim 5, wherein the elastic member protrudes from the ring shaped holder a predetermined length toward the rack stopper.

8. The apparatus of claim 5, wherein the elastic member comprises rubber.

9. The apparatus of claim 5, wherein the ring shaped holder comprises at least one of a resin and nylon.

10. The apparatus of claim 5, wherein the elastic member is fixed to the ring shaped holder.

11. The apparatus of claim 5, wherein the ring shaped holder is fixed to a end portion of the rack shaft.

12. The apparatus of claim 5, wherein the elastic member is integrally molded on the ring shaped holder.

13. The apparatus of claim 5, wherein the ring shaped holder has an annular groove and at least one D-shaped hole.

14. The apparatus of claim 13, wherein the at least one D-shaped hole comprised at least two D-shaped holes arranged at equal intervals circumferentially on the ring shaped holder.

15. The apparatus of claim 13, wherein the at least one D-shaped hole is located on a joint side of the ring shaped holder.

16. The apparatus of claim 13, wherein the at least one D-shaped hole communicate with the annular groove.

17. The apparatus of claim 13, wherein at least a portion of the elastic member is received in the at least one D-shaped hole.

18. The apparatus of claim 13, wherein the at least one D-shaped hole includes a diameter reduced portion.

19. The apparatus of claim 13, wherein at least a portion of the elastic member is received in the annular groove.

20. The apparatus of claim 5, wherein the elastic member is vulcanized-adhered to the ring shaped holder.