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A steering system for steering a machine having opposing first and second sides with first and second pairs of rotatably mounted rear wheels disposed along the respective sides and at least one rotatably mounted, spaced front wheel. The system includes at least one first drive unit and at least one

A steering system for steering a machine having opposing first and second sides with first and second pairs of rotatably mounted rear wheels disposed along the respective sides and at least one rotatably mounted, spaced front wheel. The system includes at least one first drive unit and at least one second drive unit for rotating the rear wheels of the respective pairs, and a steering input device that provides a signal to a controller that produces drive unit request signals to control the drive units to rotate the associated rear wheels along one side at rotational speeds greater than those along the other side to facilitate turning.

대표청구항 ▼

1. A steering system for steering a machine on a terrain, the machine having a front and a rear, and opposing first and second sides, the steering system comprising: a first pair of rotatably mounted rear wheels disposed along the first side of the machine, the first pair including a first wheel dis

1. A steering system for steering a machine on a terrain, the machine having a front and a rear, and opposing first and second sides, the steering system comprising: a first pair of rotatably mounted rear wheels disposed along the first side of the machine, the first pair including a first wheel disposed along a first axis and a second wheel disposed along a second axis, the first and second axes of the first pair of wheels not being coincident,a second pair of rotatably mounted rear wheels disposed along the second side of the machine, the second pair including a first wheel disposed along a first axis and a second wheel disposed along a second axis, the first and second axes of the second pair of wheels not being coincident,a first tandem support, the first pair of rear wheels being rotatably mounted to the first tandem support, the first tandem support being pivotably mounted along the first side of the machine,a second tandem support, the second pair of rear wheels being rotatably mounted to the second tandem support, the second tandem support being pivotably mounted along the second side of the machine,at least one rotatably mounted front wheel, said front wheel being spaced from said first and second pairs of rear wheels,a plurality of drive units including at least one first drive unit for rotating the rear wheels of the first pair, and at least one second drive unit for rotating the rear wheels of the second pair,a steering input device for producing a steering input signal,a controller for receiving the steering input signal and producing drive unit request signals to control the first and second drive units to rotate the associated rear wheels, the request signals causing the first drive unit to rotate the first pair of rear wheels disposed along the first side of the machine at rotational speeds greater than rotational speeds at which the second drive unit rotates the second pair of wheels disposed along the second side of the machine. 2. The steering system of claim 1 wherein the first axes of the first pair and the second pair are coincident, and the second axes of the first pair and the second pair are coincident. 3. The steering system of claim 1 wherein the plurality of drive units includes at least two first drive units for independently rotating the respective rear wheels of the first pair, and at least two second drive units for independently rotating the respective rear wheels of the second pair. 4. The steering system of claim 1 wherein the plurality of drive units includes at least two first drive units for independently rotating the respective rear wheels of the first pair, and at least two second drive units for independently rotating the respective rear wheels of the second pair. 5. The steering system of claim 1 wherein the machine includes front and rear frame sections, the frame sections being articulable relative to one another, the front wheel being rotatably coupled to the front frame section and the rear wheels being rotatably coupled to the rear frame section. 6. The steering system of claim 1 for the machine traversing a hill, the first side of the machine being disposed generally downhill and the second side being disposed generally uphill, and wherein the controller is adapted to produce request signals causing the first pair of rear wheels disposed along the first side of the machine to rotate at respective rotational speeds greater than the second pair of rear wheels disposed along the second side of the machine disposed uphill to cause the machine to move in at least one of a substantially straight line or to turn uphill. 7. The steering system of claim 1 further comprising at least a first and a second hydraulic pump and wherein the drive units are hydraulic motors, the first and second hydraulic pumps being fluidly coupled to the first and second hydraulic motors, respectively. 8. The steering system of claim 7 further including at least one sensor adapted to provide information to the controller relative to at least one of a first pump displacement, a second pump displacement, a first motor speed, a second motor speed, a speed of at least one of the wheels of the first pair, a speed of at least one of the wheels of the second pair, a speed of the front wheel, a lean angle of at least one of the wheels. 9. The steering system of claim 8 wherein the machine includes front and rear frame sections, the frame sections being articulable relative to one another, the front wheel being rotatably coupled to the front frame section and the rear wheels being rotatably coupled to the rear frame section. 10. A machine for use on a terrain, the machine comprising a mainframe,a first side,a second side, said first and second sides being opposed,a first pair of rear wheels rotatably coupled to the mainframe along the first side,a second pair of rear wheels rotatably coupled to the mainframe along the second side,a first wheel of the first pair and a first wheel of the second pair being disposed along a first axis,a second wheel of the first pair and a second wheel of the second pair being disposed along a second axis, the first and second axes not being coincident,at least one front wheel rotatably coupled to the mainframe, the front wheel being spaced from the first and second pairs of rear wheels,a plurality of drive units including at least a first drive unit disposed to rotate the rear wheels of the first pair, and at least a second drive unit disposed to rotate the rear wheels of the second pair,a steering input device for producing a steering input signal,a controller for receiving the steering input signal and producing drive unit request signals to control the first and second drive units to rotate the associated rear wheels, the request signals causing the first pair of rear wheels disposed along first side of the machine to rotate at rotational speeds greater than the rotational speeds of the second pair of rear wheels disposed along the second side of the machine. 11. The machine of claim 10 further comprising first and second tandem supports, the first pair of rear wheels being rotatably mounted to the first tandem support, the second pair of rear wheels being rotatably mounted to the second tandem support, the first tandem support being pivotably mounted along the first side of the machine, and the second tandem support being pivotably mounted along the second side of the machine. 12. The machine of claim 11 wherein the plurality of drive units includes at least two first drive units for independently rotating the respective rear wheels of the first pair, and at least two second drive units for independently rotating the respective rear wheels of the second pair. 13. The machine of claim 10 wherein the plurality of drive units includes at least two first drive units for independently rotating the respective rear wheels of the first pair, and at least two second drive units for independently rotating the respective rear wheels of the second pair. 14. The machine of claim 10 wherein the machine includes front and rear frame sections, the frame sections being articulable relative to one another, the front wheel being rotatably coupled to the front frame section and the rear wheels being rotatably coupled to the rear frame section. 15. The machine of claim 10 further comprising at least a first and a second hydraulic pump and wherein the drive units are hydraulic motors, the first and second hydraulic pumps being fluidly coupled to the first and second hydraulic motors, respectively. 16. The machine of claim 15 further including at least one sensor adapted to provide information to the controller relative to at least one of a first pump displacement, a second pump displacement, a first motor speed, a second motor speed, a speed of at least one of the wheels of the first pair, a speed of at least one of the wheels of the second pair, a speed of the front wheel, a lean angle of at least one of the wheels, wherein the front wheel is adapted to be steered and the controller is adapted produce a request signal to steer the front wheel toward a turn direction in response to the steering input signal from the steering input device, the turn direction being toward the second side of the machine, the controller further being adapted to produce drive unit request signals to cause the first pair of rear wheels disposed along the first side of the machine to rotate at respective rotational speeds greater than the rotational speed of the second pair of rear wheels disposed along the second side of the machine. 17. A method of steering a machine on a terrain, the machine having a mainframe,a first side,a second side, the first and second sides being opposed,a first pair of rear wheels rotatably coupled to the mainframe along the first side, the first pair including a first wheel disposed along a first axis and a second wheel disposed along a second axis, the first and second axes of the first pair of wheels not being coincident,a second pair of rear wheels rotatably coupled to the mainframe along the second side, the second including a first wheel disposed along a first axis and a second wheel disposed along a second axis, the first and second axes of the second pair of wheels not being coincident,at least one front wheel rotatably coupled to the mainframe in spaced relation to the first and second pairs of wheels,a plurality of drive units including at least a first drive unit disposed to rotate the rear wheels of the first pair, and at least a second drive unit disposed to rotate the rear wheels of the second pair,the method comprising the steps ofproducing a steering input signal,receiving the steering input signal,producing drive unit request signals in response to the steering input signal to control the first, second, third, and fourth drive units to rotate the associated rear wheels, androtating the pair of wheels disposed along the first side of the machine at rotational speeds greater than the rotational speeds of the pair of wheels disposed along the second side of the machine. 18. The method of claim 17 wherein the machine further includes a first wheel of the first pair and a first wheel of the second pair being disposed along a first axis, and a second wheel of the first pair and a second wheel of the second pair being disposed along a second axis, the first and second axes not being coincident. 19. The method of claim 17 further including the step of articulating the front frame section relative to the rear frame section. 20. The method of claim 17 further including providing a signal to the controller from at least one sensor adapted to provide information relative to at least one of a first pump displacement, a second pump displacement, a first motor speed, a second motor speed, a speed of at least one of the wheels of the first pair, a speed of at least one of the wheels of the second pair, a speed of the front wheel, and a lean angle of at least one of the wheels.