Active axle suspension system
An active suspension system for a rigid beam tractor axle in which the axle is connected to the chassis by two orthogonally oriented pivot points and axle movement is controlled by double-acting suspension actuators managed by a control system to improve the ride and handling characteristics of the tractor.
1. A suspension apparatus for an axle of a vehicle, the vehicle having a frame with generally opposing forward and rearward ends defining a longitudinal axis, the suspension apparatus comprising:
an elongate axle carrier having opposing first and second ends generally aligned with said longitudinal axis, a carrier mounting structure affixed adjacent said second end, said mounting structure connecting said carrier to said frame in a manner allowing said carrier to pivot about a first axis generally transverse to said longitudinal axis, and an axle pivot structure disposed adjacent said first end of said carrier and affixed thereto, said axle pivot structure aligned generally parallel to said longitudinal axis;
an axle having a laterally extending central portion with left and right ends and left and right wheels connected respectively thereto for engagement with the ground, said axle pivotally coupled to said axle pivot structure to permit said axle to pivot with respect to said axle carrier about a second axis generally parallel to said longitudinal axis;
a guide member disposed on said forward end of said carrier engaging a receiving structure connected to said frame, said guide member interacting with said receiving structure limiting relative motion of said axle carrier to pivoting motion about said first axis;
left and right suspension actuators connecting said left and right extending portions of said axle, respectively, to said frame, said suspension actuators being selectively movable in first and second opposing directions and extendable or retractable to a desired length whereby extending or retracting selective said actuators modifies the position of said left or right wheels relative to said frame; and
a control system for managing the position, extension and retraction, and the rate thereof, of said suspension actuators in response to the contour of the ground engaged by or to be engaged by said wheels thereby controlling pivoting of said axle about said first and second axes.
2. The suspension apparatus as described in claim 1 , wherein said suspension actuators are hydraulic cylinders.
3. The suspension apparatus as described in claim 1 , wherein said guide member is at least one roller.
4. The suspension apparatus as described in claim 1 , wherein said control system actuates said left and right suspension actuators independently of one another.
5. The suspension apparatus as described in claim 4 , wherein said control system simultaneously controls pivotal motions of said axle about said first and second axes.
6. The suspension apparatus as described in claim 2 , further comprising left and right position signals, each said signal having a value corresponding to the said length of each respective said suspension actuator.
7. The suspension apparatus as described in claim 6 , further comprising an apparatus for sensing the contour of the ground engaging each wheel and communicating a signal to said control system.
8. The suspension apparatus as described in claim 7 , further comprising an apparatus for sensing the contour of the ground to be engaged by each wheel and communicating a signal to said control system.
9. The suspension apparatus as described in claim 8 , wherein said control system actuates said left and right suspension actuators independently of one another.
10. The suspension apparatus as described in claim 9 , wherein said control system simultaneously controls pivotal motions of said axle about said first and second axes.
11. The suspension apparatus as described in claim 10 , further comprising left and right position signals, each said signal having a value corresponding to the said length of each respective said suspension actuator.
12. The suspension apparatus as described in claim 11 , further comprising an apparatus for sensing the contour of the ground engaging each wheel and communicating a signal to said control system.
13. The suspension apparatus as described in claim 12 , further comprising an apparatus for sensing the contour of the ground to be engaged by each wheel and communicating a signal to said control system.
14. In an agricultural tractor having a frame with generally opposing forward and rearward ends defining a longitudinal axis, a high pin rigid front axle pivotally connected to the tractor to permit said axle to pivot about an axis generally parallel to the longitudinal axis, the tractor further comprising:
an elongate axle carrier having opposing first and second ends generally aligned with said longitudinal axis, a carrier mounting structure affixed adjacent said second end, said mounting structure connecting said carrier to said frame in a manner allowing said carrier to pivot about a first pivot axis generally transverse to said longitudinal axis, and an axle pivot structure disposed adjacent said first end of said carrier and affixed thereto, said axle pivot structure having a second pivot axis aligned generally parallel to said longitudinal axis and connected to the axle thereby permitting the axle to pivot with respect to said axle carrier about said second pivot axis;
a guide member disposed on said forward end of said carrier engaging a receiving structure connected to said frame, said guide member interacting with said receiving structure limiting relative motion of said axle carrier to pivoting motion about said a first pivot axis;
left and right suspension actuators connecting said left and right extending portions of the axle, respectively, to said frame, said suspension actuators being selectively movable in first and second opposing directions and extendable or retractable to a desired length whereby extending or retracting selective said actuators modifies the position of said left or right wheels relative to said frame; and
a control system for managing the position, extension and retraction, and the rate thereof, of said suspension actuators in response to the contour of the ground engaged by or to be engaged by said wheels thereby controlling pivoting of said axle about said first and second pivot axes.
15. The tractor as described in claim 14 wherein said suspension actuators are hydraulic cylinders.
16. The tractor as described in claim 15 , wherein said control system actuates said left and right suspension actuators independently of one another.
17. The tractor as described in claim 16 , wherein said control system simultaneously controls pivotal motions of said axle about said first and second pivot axes.
18. The tractor as described in claim 17 , further comprising left and right position signals, each said signal having a value corresponding to the said length of each respective said suspension actuator.
19. The tractor as described in claim 16 , further comprising an apparatus for sensing the contour of the ground engaging each wheel and communicating a signal to said control system.
20. The tractor as described in claim 17 , further comprising an apparatus for sensing the contour of the ground to be engaged by each wheel and communicating a signal to said control system.