IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0211091
(2002-08-02)
|
발명자
/ 주소 |
|
대리인 / 주소 |
Nexsen Pruet Adams Kleemeier, LLC
|
인용정보 |
피인용 횟수 :
14 인용 특허 :
31 |
초록
▼
A steer wheel control system having a centering unit for resisting off-center movement of the steered wheels of a vehicle and returning them to a selected center position after each such movement, and a trim unit for remotely varying the selected center position. A resistance force and a return forc
A steer wheel control system having a centering unit for resisting off-center movement of the steered wheels of a vehicle and returning them to a selected center position after each such movement, and a trim unit for remotely varying the selected center position. A resistance force and a return force may also be varied remotely. A plurality of passages and check valves make the trim unit operable by a single solenoid valve mounted internally on an intermediate head between the trim unit and the centering unit.
대표청구항
▼
1. An apparatus for holding at a center position at least one steerable member mounted on a frame means for movement to either side of the center position, said apparatus comprising linkage means of variable length extending between said steerable member and said frame means, the length of said link
1. An apparatus for holding at a center position at least one steerable member mounted on a frame means for movement to either side of the center position, said apparatus comprising linkage means of variable length extending between said steerable member and said frame means, the length of said linkage means defining said center position, and accumulator means for holding a supply of fluid and means for pressurizing the fluid held in said accumulator means;wherein said linkage means comprises centering means for providing a resistance force resisting steering forces tending to move said steerable member to either side of the center position, and trim means for transmitting said steering forces to said centering means;wherein said trim means comprises:a trim piston,trim cylinder means providing a portion of said linkage means and cooperating with said trim piston to form first and second trim chambers one on each side of said trim piston,and trim fluid means for providing a flow of trim fluid between said accumulator means and each of said trim chambers and comprising trim valve means operable between a closed position for preventing said trim fluid flow so that said trim piston is held in a locked position, and an open position for allowing said trim fluid flow so that said trim piston is free to move away from said locked position in said trim cylinder, said trim piston movement causing trim fluid flow to one of said trim chambers and trim fluid flow from the other of said trim chambers to permit trimming movement of said steerable member to another center position by changing the length of said linkage means in response to said steering forces;wherein said centering means comprises:centering cylinder means providing a portion of said linkage means,centering piston means cooperating with said centering cylinder means to form first and second centering chambers, and being arranged for movement in a first direction for compressing a fluid within said first centering chamber and for movement in a second direction for compressing a fluid within said second centering chamber,centering rod means providing a portion of said linkage means and arranged for movement with said centering piston means to either side of a neutral position corresponding to said center position,and centering fluid means for providing a pressurized centering fluid in each of said first and second centering chambers so that fluid pressure provides said resistance force by biasing said centering piston means toward said neutral position upon movement of said steerable member toward either side of said center position;wherein said trim cylinder means and said centering cylinder means are interconnected by an intermediate head member and said trim valve means is located in said intermediate head member;and wherein said trim fluid means further comprises:conduit means for providing fluid communication between said accumulator means and said centering chambers,a first supply passage in said intermediate head member for communicating with at least one of said centering chambers to supply trim fluid to said first trim chamber,a second supply passage in said intermediate head member for communicating with at least one of said centering chambers to supply trim fluid to said second trim chamber,a first return passage in said intermediate head member for communicating with one of said trim chambers to return trim fluid to said conduit means,a second return passage in said intermediate head member for communicating with the other of trim chambers to return trim fluid to said conduit means,a first supply valve for preventing reverse fluid flow in said first supply passage,a second supply valve for preventing reverse fluid flow in said second supply passage,a first return valve for preventing reverse fluid flow in said first return passage,and a second return valve for preventing reverse fluid flow in said second return passage;and wherein said apparatus further comprises operating means activatable from a remote location for operating said trim valve means between said closed and open positions. 2. An apparatus according to claim 1 wherein said trim valve means comprises a valve member arranged for reciprocating movement between a closing position for causing simultaneously closure of said first and second return passages and an opening position for causing simultaneously opening of said first and second return passages. 3. An apparatus according to claim 2 wherein said trim valve means is carried by said intermediate head member internally within said centering cylinder means or said trim cylinder means. 4. An apparatus according to claim 3 wherein said trim valve means is carried by said intermediate head member internally within said centering cylinder means and comprises an actuator at least partially projecting into an adjacent one of said centering chambers, and wherein said centering piston means comprises a piston member arranged to reciprocate in said adjacent centering chamber, said piston member having a recess for receiving a projecting part of said actuator during at least a portion of said reciprocation. 5. An apparatus according to claim 1 wherein said fluid is a liquid and said accumulator means comprises a reservoir for holding a supply of said liquid and a gas chamber in fluid communication with said reservoir, and wherein said apparatus further comprises means for pressurizing said gas chamber with a gas to pressurize the liquid in said reservoir, and means for controllably varying the pressure of said gas so as to vary said liquid pressurization. 6. An apparatus according to claim 1 wherein said pressurizing means includes means for controllably varying said fluid pressure so as to vary at least one of said resistance force and said return force. 7. An apparatus according to claim 1 wherein the fluid supplied by said accumulator means is a liquid and said liquid flows to and from said centering chambers via said conduit means, and wherein said conduit means comprises a pressure actuated valve means for preventing fluid flow from said centering chambers until an engagement between said centering rod means and said centering piston means produces a fluid pressure differential above an accumulator pressure by a selected amount. 8. An apparatus according to claim 7 wherein said pressure actuated valve means includes mean for controllably varying said selected amount of fluid pressure differential. 9. An apparatus according to claim 1 for a vehicle having a steering system comprising said at least one steerable member, wherein the fluid supplied by said accumulator means is a liquid and said liquid flows to and from said centering chambers via said conduit means; and wherein said pressurizing means comprises gas pressure means for applying pressure of a pressurized gas to said liquid in a liquid reservoir, and control means for automatically adjusting the amount of said gas pressure in response to the speed of said vehicle. 10. An apparatus according to claim 1 for a vehicle having a power steering unit for providing steering power to said steerable member, said apparatus further comprising means for preventing fluid pressure in said accumulator means in the absence of steering power from said power steering unit. 11. An apparatus according to claim 1 wherein said centering piston means comprises a first piston cooperating with said centering cylinder means to define said first centering chamber, and a second piston cooperating with said centering cylinder means to define said second centering chamber, each of said first and second pistons being arranged to move independently of the other between a retracted position and a position for compressing a fluid within its corresponding chamber;wherein said centering rod means comprises a rod head arranged for movement to either side of a neutral position corresponding to said center position, and an elongated rod for causing said rod head to engage each of said centering pistons independently of the other so that movement of said rod head away from said neutral position to one side causes compressive movement of said first centering piston without moving said second centering piston and movement of said rod head away from said neutral position to the other side causes compressive movement of said second centering piston without moving said first centering piston; and,wherein said apparatus further comprises connecting means for connecting said elongated rod or said centering cylinder means to said steerable member for movement therewith. 12. An apparatus according to claim 11 wherein said fluid is a liquid and said accumulator means comprises a reservoir for holding a supply of said liquid, a gas chamber for pressurizing the liquid held in said reservoir and an outlet for providing fluid communication between said liquid reservoir and said conduit means; and,wherein said pressurizing means includes gas means for pressurizing said gas chamber with a gas to pressurize the liquid in said reservoir, said gas means comprising control means for selectively varying the pressurization of said gas chamber so as to controllably vary said liquid pressurization. 13. An apparatus according to claim 12 for a vehicle having a steering system comprising said at least one steerable member, wherein said control means includes means for automatically varying said gas chamber pressurization in response to the speed of said vehicle. 14. An apparatus according to claim 1, wherein said trim valve means is carried by said intermediate head member internally within said centering cylinder means or said trim cylinder means; and wherein said operating means comprises a solenoid carried by said intermediate head member and arranged to open and close said trim valve means, a remote actuator for activating said solenoid, and electrical connecting means connecting said solenoid to said actuator. 15. An apparatus according to claim 14, wherein said electrical connecting means comprises an axial conducting member electrically connected to said solenoid, a transverse conducting member electrically connected to said remote actuator, and a conducting spring member resiliently connecting said axial and transverse members.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.