Vehicle with offset extendible axles and independent four-wheel steering control
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
B62D-007/06
B62D-005/06
출원번호
US-0337385
(2003-01-07)
발명자
/ 주소
Bean, Andrew J.
Blumberg, Michael J.
Livdahl, Richard J.
Mellott, Lex A.
출원인 / 주소
JLG Industries, Inc.
대리인 / 주소
Nixon & Vanderhye P.C.
인용정보
피인용 횟수 :
24인용 특허 :
16
초록▼
A vehicle includes a chassis supporting two front axle assemblies and two rear axle assemblies. Each of the front and rear axle assemblies includes an extendible and retractable axle supporting an independently steerable wheel and a steering mechanism. The axles of the respective front and rear axle
A vehicle includes a chassis supporting two front axle assemblies and two rear axle assemblies. Each of the front and rear axle assemblies includes an extendible and retractable axle supporting an independently steerable wheel and a steering mechanism. The axles of the respective front and rear axle assemblies are offset from each other. By providing independently steerable wheels, the vehicle is operable in a plurality of steering modes including two-wheel steer, crab steer and coordinated steer. A steering angle for each steering wheel is determined according to a steering angle of an inside front wheel on a turn-by-turn basis.
대표청구항▼
1. A vehicle comprising a chassis supporting two front axle assemblies and two rear axle assemblies, each of the front and rear axle assemblies including an extendible and retractable axle supporting an independently steerable wheel and a steering mechanism,wherein the axles of the two front axle as
1. A vehicle comprising a chassis supporting two front axle assemblies and two rear axle assemblies, each of the front and rear axle assemblies including an extendible and retractable axle supporting an independently steerable wheel and a steering mechanism,wherein the axles of the two front axle assemblies are offset from each other, and wherein the axles of the two rear axle assemblies are offset from each other,the vehicle being operable in a plurality of steering modes including two-wheel steer, crab steer and coordinated steer, wherein a steering angle for each steering wheel is determined according to a steering angle of an inside front wheel on a turn-by-turn basis, the inside front wheel changing according to a turning direction. 2. A vehicle according to claim 1, further comprising a wheel angle sensor disposed in cooperation with each wheel. 3. A vehicle according to claim 2, wherein a drive speed of the vehicle is controlled on a proportional basis dependent on steer angle. 4. A vehicle according to claim 1, wherein in the crab steering mode, all of the wheels are controlled to substantially the same angle. 5. A vehicle according to claim 1, wherein in the coordinated steering mode, a projected vehicle pivot point is determined by an intercept of a line drawn perpendicularly through a center of the inside front wheel and a line drawn horizontally from a midpoint between the front and rear axle assemblies. 6. A vehicle according to claim 1, further comprising an operator-controlled steering switch communicating with at least the steering mechanisms of the front axle assemblies, wherein the inside front wheel steering angle is determined according to a wheel position of the front inside wheel. 7. A vehicle according to claim 1, wherein in the two-wheel steering mode, a projected vehicle pivot point is determined by an intercept of a line drawn perpendicularly through a center of the inside front wheel and a line drawn horizontally from a midpoint between the axles of the two rear axle assemblies. 8. A vehicle according to claim 1, wherein each of the front and rear axle assemblies comprises a hydraulic cylinder coupled with the extendible and retractable axle, wherein fluid flow to the hydraulic cylinders is controlled with two directional valves, a first valve to extend and retract the axles of the front axle assemblies and a second valve to extend and retract the axles of the rear axle assemblies. 9. A vehicle according to claim 8, wherein the hydraulic cylinders are controlled to effect extension and retraction of the axles only when the vehicle is traveling above a predetermined minimum speed. 10. A vehicle according to claim 9, further comprising four digital or analog switches coupled with the axles, respectively, the digital or analog switches indicating that the axles are fully extended. 11. A vehicle according to claim 10, wherein drive and steering functions are controlled according to signals from the digital or analog switches. 12. A vehicle comprising a chassis supporting two front axle assemblies and two rear axle assemblies, each of the front and rear axle assemblies including an extendible and retractable axle supporting an independently steerable wheel and a steering mechanism,wherein the axles of the two front axle assemblies are offset from each other, and wherein the axles of the two rear axle assemblies are offset from each other,the vehicle being operable in a plurality of steering modes including two-wheel steer, crab steer and coordinated steer, wherein a steering angle for each steering wheel is determined according to a steering angle of an inside front wheel on a turn-by-turn basis, the inside front wheel changing according to a turning direction,the vehicle further comprising a left drive pump operatively coupled with the left front and rear steerable wheels and a right drive pump operatively coupled with the right front and rear steerable wheels, the left and right drive pumps independent ly controlling vehicle speed for respective sides of the vehicle. 13. A method of controlling vehicle steering and axle position, the vehicle including a chassis supporting two front axle assemblies and two rear axle assemblies, each of the front and rear axle assemblies including an extendible and retractable axle supporting an independently steerable wheel and a steering mechanism, wherein the axles of the two front axle assemblies are offset from each other, and wherein the axles of the two rear axle assemblies are offset from each other, the method comprising:selectively operating the vehicle in one of a plurality of steering modes including two-wheel steer, crab steer and coordinated steer; anddetermining a steering angle for each steering wheel according to a steering angle of an inside front wheel on a turn-by-turn basis, the inside front wheel changing according to a turning direction. 14. A method according to claim 13, further comprising, in the coordinated steering mode, determining a projected vehicle pivot point by an intercept of a line drawn perpendicularly through a center of the inside front wheel and a line drawn horizontally from a midpoint between the front and rear axle assemblies. 15. A method according to claim 14, further comprising, in the coordinated steering mode, controlling inside wheel speed to be slower than outside wheel speed. 16. A method according to claim 13, further comprising, in the two-wheel steering mode, determining a projected vehicle pivot point by an intercept of a line drawn perpendicularly through a center of the inside front wheel and a line drawn horizontally from a midpoint between the axles of the two rear axle assemblies. 17. A method according to claim 13, wherein each of the front and rear axle assemblies comprises a hydraulic cylinder coupled with the extendible and retractable axle, the method further comprising controlling fluid flow to the hydraulic cylinders with two valves, a first valve to extend the axle and a second valve to retract the axle. 18. A method according to claim 17, wherein the hydraulic cylinders are controlled to effect extension and retraction of the axles only when the vehicle is traveling above a predetermined minimum speed. 19. A method according to claim 18, further comprising four digital or analog switches coupled with the axles, respectively, the digital or analog switches indicating that the axles are fully extended, wherein drive and steering functions are controlled according to signals from the digital or analog switches.
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이 특허에 인용된 특허 (16)
Weddle Kenneth E., Apparatus and method for locking an adjustable width axle assembly of a crop sprayer.
Ward Wayne L. (Greencastle PA) Backer Robert D. (Rouzerville PA) Spidel Jeffrey L. (St. Thomas PA) Hade ; Jr. Donald C. (Waynesboro PA), Tie rod extendable and retractable telescopic axle assembly.
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