US4570736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual flow variable assist power steering gear mechanism
Assignee: Visteon Global Technologies Inc
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Filing: 1985-01-07
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Granted: 1986-02-18
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Expires: 2005-01-07
Abstract
Abstract A power steering gear mechanism for an automotive vehicle having a pressure operated vehicle steering mechanism controlled by a rotary valve with primary and secondary valve portions located in angularly spaced relationship on a common transverse reference plane wherein the primary valve portion develops a fast-rising steering pressure characteristic for incremental changes in steering torque at low driving speeds and a flatter or more gradual steering pressure rise characteristic for incremental changes in steering torque at high driving speeds, the latter resulting from the action of the secondary valve portion which functions in cooperation with the primary valve portion whereby the pressure versus torque relationship is optimized for parking maneuvers, for driving maneuvers and for center-feel, the change from the low speed steering mode to the high speed steering mode being gradual whereby the center-feel increases in proportion to increasing road speed.
Inventors
- 👤 Raymond D. Waldorf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:59
CPC Classifications
B; B62; B62D; B62D6/00; B62D6/02; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86638; Y10T137/86646; Y10T137/86654
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
345 words
In a fluid pressure operated power steering gear mechanism having a fluid flow source, a pressure movable part adapted to be connected to a steering linkage for a vehicle, a drive member connected to said pressure movable part, a driving shaft connected to said drive member; the connection between said drive member and said driving shaft comprising a torsion member that accommodates angular displacement of said drive member relative to said driving shaft; a rotary valve means situated in and partly defining pressure distribution and flow return passages extending to said pressure movable part and to said fluid flow source to effect pressure differential forces acting on said pressure movable part; said valve means comprising an internal valve member and a surrounding sleeve; said internal valve member having formed thereon two sets of valve lands, one set being circumferentially offset relative to the other, two sets of internal valve lands formed in said sleeve respectively registering with the valve land sets of said internal valve member; said valve sleeve being connected operatively to said drive member for rotational movement therewith; vehicle speed sensitive valve means for distributing fluid flow only to a first of said sets of valve lands at low vehicle speeds and for distributing fluid flow to both sets of said valve lands at high vehicle speeds; said internal valve member being connected to and rotatable with said driving shaft, the first set of said registering valve lands being adapted to control pressure distribution to said pressure movable part during initial deflection of said torsion member and being adapted to effectively increase the magnitude of the pressure distributed to said pressure movable part as said torsion member deflection increases within a first range of deflection during operation at low vehicle speeds and the other set of registering valve lands being adapted to control pressure distribution through said passages to said pressure movable part upon deflection of said torsion bar within a greater range of deflection of said torsion bar as fluid is distributed simultaneously to both valve land sets at higher vehicle speeds.
Claim 2
Dependent Claim
345 words
In a fluid pressure operated power steering gear mechanism having a fluid flow source, a pressure movable part adapted to be connected to a steering linkage for a vehicle, a drive member connected to said pressure movable part, a driving shaft connected to said drive member; the connection between said drive member and said driving shaft comprising a torsion member that accommodates angular displacement of said drive member relative to said driving shaft; a rotary valve means situated in and partly defining pressure distribution and flow return passages extending to said pressure movable part and to said fluid flow source to effect pressure differential forces acting on said pressure movable part; said valve means comprising an internal valve member and a surrounding sleeve; said internal valve member having formed thereon two sets of valve lands, one set being circumferentially offset relative to the other, two sets of internal valve lands formed in said sleeve respectively registering with the valve land sets of said internal valve member; said valve sleeve being connected operatively to said drive member for rotational movement therewith; vehicle speed sensitive valve means for distributing fluid flow only to a first of said sets of valve lands at low vehicle speeds and for distributing fluid flow to both sets of said valve lands at high vehicle speeds; said internal valve member being connected to and rotatable with said driving shaft, the first set of said registering valve lands being adapted to control pressure distribution to said pressure movable part during initial deflection of said torsion member and being adapted to effectively increase the magnitude of the pressure distributed to said pressure movable part as said torsion member deflection increases within a first range of deflection during operation at low vehicle speeds and the other set of registering valve lands being adapted to control pressure distribution through said passages to said pressure movable part upon deflection of said torsion bar within a greater range of deflection of said torsion bar as fluid is distributed simultaneously to both valve land sets at higher vehicle speeds.
Claim 3
Dependent Claim
124 words
The combination as set forth in claim 1 wherein the first set of said registering valve lands comprises a primary valve means for effectively distributing steering pressure to said pressure movable part and increasing the magnitude of the pressure distributed to said pressure movable part upon an increase in the magnitude of the torque applied to said driving shaft and wherein the other set of registering valve lands comprises a secondary valve means for distributing pressure to said pressure movable part in parallel relationship with respect to the primary valve means thereby increasing the magnitude of the driving shaft torque required to reach a given steering pressure level when the fluid flow is distributed simultaneously to both valve land sets at higher vehicle speeds.
Claim 4
Dependent Claim
82 words
The combination as set forth in claim 1 wherein said passages include said rotary valve means and separate passage portions for supplying flow to each of said sets of registering valve lands, said passages including a fluid flow valve means for supplying fluid from said fluid flow source to said second valve land set, and vehicle speed responsive means for actuating said fluid flow valve means to effect flow to both valve land sets when the vehicle speed exceeds a predetermined value.
Claim 5
Dependent Claim
82 words
The combination as set forth in claim 2 wherein said passages include said rotary valve means and separate passage portions for supplying flow to each of said sets of registering valve lands, said passages including a fluid flow valve means for supplying fluid from said fluid flow source to said second valve land set, and vehicle speed responsive means for actuating said fluid flow valve means to effect flow to both valve land sets when the vehicle speed exceeds a predetermined value.
Claim 6
Dependent Claim
91 words
The combination as set forth in claim 3 wherein said valve lands of said internal valve member are arranged in a high speed set and a low speed set angularly spaced one with respect to the other, the lands of each set being defined by axially extending slots in said inner valve member, the passage portion supplying fluid to said high speed set communicating with said slots for said high speed set, the passage portions supplying fluid to said low speed set communicating with the slots for said low speed set.
Claim 7
Dependent Claim
139 words
The combination as set forth in claim 3 wherein said valve lands of said internal valve member are arranged in a high speed set and a low speed set angularly spaced one with respect to the other, the lands of each set being defined by axially extending slots in said inner valve member, the passage portions supplying fluid to said high speed set communicating with said slots for said high speed set across metering lands defined by said internal lands in said sleeve and the lands of said high speed set in said inner valve member, the passage portions supplying fluid to said low speed set communicating with said slots for said low speed set across metering lands defined by said internal lands in said sleeve and the lands of said low speed set in said inner valve member.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-17 | 1989-08-19 | 1990-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-17 | 1993-08-19 | 1994-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-17 | 1997-08-19 | 1998-02-18 | $7700.00 | Window Closed / Lapsed |