All-wheel steering
First Claim
1. All-wheel steering for motor vehicles having front wheel steering actuated by a steering handwheel and motor-driveable rear wheel steering which is actuated by a control means as a function of a vehicle parameter through comparison of set values and actual values of the rear-wheel steering angle, comprising:
- the front wheel steering is positively coupled to a first double-acting piston-cylinder unit positively coupled to the front wheel steering and having two swept chambers of different effective piston area and a piston which, in a central straight-ahead position of the front wheel steering, connects the two swept chambers of the piston-cylinder unit;
a self-locking-free motor drive provided in the rear wheel steering and prestressed by a spring arrangement into a straight-ahead position of the rear wheel steering;
said self-locking-free motor drive being positively coupled to a second double-acting piston-cylinder unit;
the second double-acting piston-cylinder unit having two swept chambers which have an equal effective piston area ratio with the swept chambers of the first double-acting piston-cylinder unit;
said two piston-cylinder units fluidly coupled to one another via two connecting hydraulic lines with one line connecting the larger swept chambers of the two piston-cylinder units and the other line connecting the smaller swept chambers;
a third double-acting piston-cylinder unit having two swept chambers which have an equal effective piston area ratio with the swept chambers of the first and second piston-cylinder units, the larger swept chamber of the third piston-cylinder unit being connectable via a shut-off valve to the line connecting the larger swept chambers of the two other piston-cylinder units and the smaller swept chamber of the third piston cylinder unit being connectable via a further shut-off valve to the other of the two lines connecting the smaller chambers of the two other piston-cylinder units;
wherein, when the two shut-off valves are closed, front wheel steering and rear wheel steering are hydraulically positively connected by the two lines to produce a deflection in the same direction of front and rear wheels.
1 Assignment
0 Petitions
Accused Products
Abstract
An all-wheel steering control or regulating device for vehicle rear wheel steering, which is motor-driven and permits any desired predeterminable steering angles of the rear wheels as a function of the steering angles of the front wheels or other parameters. In the event of error detection in the system, a drive motor of the rear wheel steering is switched to an inoperative condition and a hydraulic positive coupling between front wheel steering and rear wheel steering is simultaneously established by means of separate piston-cylinder units, with the result that the rear wheels are steered simultaneously with the front wheels.
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Citations
16 Claims
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1. All-wheel steering for motor vehicles having front wheel steering actuated by a steering handwheel and motor-driveable rear wheel steering which is actuated by a control means as a function of a vehicle parameter through comparison of set values and actual values of the rear-wheel steering angle, comprising:
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the front wheel steering is positively coupled to a first double-acting piston-cylinder unit positively coupled to the front wheel steering and having two swept chambers of different effective piston area and a piston which, in a central straight-ahead position of the front wheel steering, connects the two swept chambers of the piston-cylinder unit; a self-locking-free motor drive provided in the rear wheel steering and prestressed by a spring arrangement into a straight-ahead position of the rear wheel steering; said self-locking-free motor drive being positively coupled to a second double-acting piston-cylinder unit; the second double-acting piston-cylinder unit having two swept chambers which have an equal effective piston area ratio with the swept chambers of the first double-acting piston-cylinder unit; said two piston-cylinder units fluidly coupled to one another via two connecting hydraulic lines with one line connecting the larger swept chambers of the two piston-cylinder units and the other line connecting the smaller swept chambers; a third double-acting piston-cylinder unit having two swept chambers which have an equal effective piston area ratio with the swept chambers of the first and second piston-cylinder units, the larger swept chamber of the third piston-cylinder unit being connectable via a shut-off valve to the line connecting the larger swept chambers of the two other piston-cylinder units and the smaller swept chamber of the third piston cylinder unit being connectable via a further shut-off valve to the other of the two lines connecting the smaller chambers of the two other piston-cylinder units; wherein, when the two shut-off valves are closed, front wheel steering and rear wheel steering are hydraulically positively connected by the two lines to produce a deflection in the same direction of front and rear wheels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. All-wheel steering for motor vehicles having front wheel steering actuated by a steering handwheel and motor-driveable rear wheel steering which is actuated by a control means as a function of a vehicle parameter through comparison of set values and actual values of the rear-wheel steering angle, comprising:
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a first double-acting piston-cylinder unit positively coupled to the front wheel steering and having two swept chambers of different effective piston area and a piston which, in a central straight-ahead position of the front wheel steering, connects the two swept chambers of the piston-cylinder unit; a self-locking-free motor drive provided at the rear wheel steering and prestressed by a spring arrangement into a straight-ahead position of rear wheel steering; said self-locking-free motor drive being positively coupled to a second double-acting piston-cylinder unit; the second double-acting piston-cylinder unit having swept chambers of equal effective piston area ratio with the swept chambers of the first double-acting piston-cylinder unit; said two piston-cylinder units fluidly coupled to one another via two connecting hydraulic lines with one line connecting the one swept chambers of the two piston-cylinder units and the other line connecting the other swept chambers; a third piston-cylinder unit having swept chambers of equal effective piston area ratio with the swept chambers of the first and second piston-cylinders units, being arranged with its one swept chamber connectable via a shut-off valve to the line connecting the one swept chamber of the two other piston-cylinder units and the other swept chamber of the third piston-cylinder unit connectable via a further shut-off valve to the other of the two lines connecting the other chambers of the two other piston-cylinder unit; wherein, when the two shut-off valves are closed, front wheel steering and rear wheel steering are hydraulically positively connected by the two lines to produce a deflection in the same direction of front and rear wheels. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification