US3817151A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power steering device
Assignee: Toyoda Koki KK
•
Filing: 1973-05-08
•
Granted: 1974-06-18
•
Expires: 1993-05-08
Abstract
Abstract A power steering device having a servo-valve for distributing fluid under pressure to a power cylinder unit connected to the servo-valve and serving to steer a vehicle, and comprising a variable restrictor in which a coil spring is provided across an outlet passage through which the fluid from the servo-valve is led to a reservoir. The coil spring variable restrictor is provided in the outlet passage perpendicular thereto and is actuated in response to the steering actuation for applying a back pressure so as to prevent a restriction noise which usually is generated in servo-valves when the same are actuated.
Inventors
- 👤 M Kawabata
- 👤 K Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:13
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/20; B62D5/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
134 words
In a power steering device having a hydraulic power cylinder means serving to actuate steering tires and a servo-valve means connected to said hydraulic power cylinder means serving to distribute fluid under pressure to said hydraulic power cylinder means in response to the movement of a steering handle, said servo-valve means having inlet and outlet passages respectively connected with a hydraulic source and a reservoir, the improvement comprising: piston member means slidably mounted in valve cylinder means provided across said outlet passage; coil spring means provided in said valve cylinder means across said outlet passage, said coil spring means being compressible by said piston member means for restricting fluid flow through said outlet passage; and means for moving said piston member means for compressing said coil spring means when said steering handle is actuated.
Claim 2
Dependent Claim
134 words
In a power steering device having a hydraulic power cylinder means serving to actuate steering tires and a servo-valve means connected to said hydraulic power cylinder means serving to distribute fluid under pressure to said hydraulic power cylinder means in response to the movement of a steering handle, said servo-valve means having inlet and outlet passages respectively connected with a hydraulic source and a reservoir, the improvement comprising: piston member means slidably mounted in valve cylinder means provided across said outlet passage; coil spring means provided in said valve cylinder means across said outlet passage, said coil spring means being compressible by said piston member means for restricting fluid flow through said outlet passage; and means for moving said piston member means for compressing said coil spring means when said steering handle is actuated.
Claim 3
Dependent Claim
76 words
A power steering device according to claim 1, wherein said piston member means comprises first and second piston members and said coil spring means is disposed therebetween, and wherein one of the ends of said first and second piston members is respectively subjected to the pressure in opposing cylinder chambers of said hydraulic power cylinder means through first and second passages for moving the same when the pressure in one of said cylinder chambers is increased.
Claim 4
Dependent Claim
44 words
A power steering device according to claim 2, wherein at least one of said first and second piston members has a projection serving to limit the movement of said first and second piston members for defining the compressing amount of said coil spring means.
Claim 5
Dependent Claim
32 words
A power steering device according to claim 1, wherein the diameter of said valve cylinder means is larger than the outer diameter of said coil spring means by a predetermined small amount.
Claim 6
Dependent Claim
133 words
A power steering device according to claim 1, wherein said valve cylinder means comprises first and second valve cylinders respectively provided across said outlet passage for slidably receiving a first and a second piston member, and said coil spring means comprises first and second coil springs provided respectively in said first and second valve cylinders across said outlet passage, and one end of each of said piston members is respectively subjected to the pressure in opposing chambers of said hydraulic power cylinder means for moving the same and compressing one of said first and second coil springs when the fluid pressure in one of opposing cylinder chambers is increased, whereby the fluid through said outlet passage is restricted by one of said first and second coil springs when the steering handle is actuated.
Claim 7
Dependent Claim
59 words
A power steering device according to claim 1, wherein said piston member means is a stepped piston member and the stepped end surfaces thereof are respectively subjected to the pressure in opposing cylinder chambers of said hydraulic power cylinder means for moving the same and compressing said coil spring means to restrict the fluid flow through said outlet passage.
Claim 8
Dependent Claim
52 words
A power steering device according to claim 1, wherein said piston member means is a single piston member and one end thereof is subjected to the pressure in said inlet passage for moving the same so as to compress said Coil spring means when the pressure in the inlet passage is increased.
Claim 9
Dependent Claim
29 words
A power steering device according to claim 7, further comprising means for stopping the movement of said piston member for limiting the compressing amount of said coil spring means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |