Monotube active suspension system having different system layouts for controlling pump flow distribution

1. An hydraulic actuator circuit for use with first and second shock absorbers, wherein said first and second shock absorbers each include a piston disposed within a housing, and wherein the piston helps define upper and lower working chambers within the housing, the hydraulic actuator circuit comprising:

a motor;

a first pump, driven by the motor, and operably associated with the first shock absorber and with the motor;

a second pump, driven by the motor, and operably associated with the second shock absorber and with the motor;

a first accumulator in communication with both of the first and second pumps;

a second accumulator in communication with the first accumulator, and the upper and lower working chambers of the first shock absorber;

a first switch valve operably associated with the upper and lower working chambers of the first shock absorber, and with the first pump, for assisting in controlling fluid flow into the upper and lower chambers of the first shock absorber; and

a second switch valve operably associated with the upper and lower working chambers of the second shock absorber, and with the second pump, for assisting in controlling fluid flow into the upper and lower chambers of the second shock absorber.

2. The hydraulic actuator circuit of claim 1 , further comprising:

a first valve assembly associated with the upper working chamber of the first shock absorber and in communication with the second accumulator; and

a second valve assembly operably associated with the lower working chamber of the first shock absorber and in communication with the second accumulator.

3. The hydraulic actuator circuit of claim 2 , wherein the first and second valve assemblies each comprise a pressure relief valve.

4. The hydraulic actuator circuit of claim 3 , wherein the third and fourth assemblies each comprise a pressure relief valve.

5. The hydraulic actuator circuit of claim 3 , wherein the third and fourth valve assemblies each comprise a controlled restrictor.

6. The hydraulic actuator circuit of claim 2 , wherein the first and second valve assemblies each comprise a controlled restrictor.

7. The hydraulic actuator circuit of claim 1 , further comprising a third accumulator in communication with the first accumulator, and the upper and lower working chambers of the second shock absorber.

8. The hydraulic actuator circuit of claim 7 , further comprising:

a third valve assembly operably associated with the upper working chamber of the second shock absorber and in communication with the third accumulator; and

a fourth valve assembly associated with the lower working chamber of the second shock absorber and in communication with the third accumulator.

9. The hydraulic actuator circuit of claim 1 , further comprising a pair of one way check valves disposed between the first switch valve and the upper working chamber and the lower working chamber, respectively, of the first shock absorber.

10. The hydraulic actuator circuit of claim 1 , further comprising a pair of one way check valves disposed between the second switch valve and the upper working chamber and the lower working chamber, respectively, of the second shock absorber.

11. The hydraulic actuator of circuit of claim 7 , wherein the first, second and third accumulators are in direct communication with one another.

12. The hydraulic actuator circuit of claim 11 , wherein the first, second and third accumulators are in direct communication with both of the first and second pumps.

13. The hydraulic actuator of claim 1 , further comprising:

a third pump, driven by the motor, and operably associated with a third shock absorber; and

a fourth pump, driven by the motor, and operably associated with a fourth shock absorber.

14. The hydraulic actuator of claim 13 , further comprising:

a third accumulator in communication with the first accumulator, and the upper and lower working chambers of the second shock absorber;

a fourth accumulator in direct communication with the third and fourth pumps;

a fifth accumulator in direct communication with the third accumulator, and in communication with upper and lower chambers of the third shock absorber; and

a sixth accumulator in direct communication with the third accumulator, and in communication with upper and lower chambers of the fourth shock absorber.

15. An hydraulic actuator circuit for use with first, second, third and fourth shock absorbers, wherein said shock absorbers each include a piston disposed within a housing, and wherein the piston helps define upper and lower working chambers within the housing of each of the shock absorbers, the hydraulic actuator circuit comprising:

a motor;

a pump, driven by the motor;

a first accumulator in communication with the pump;

a first switch valve in direct communication with the pump for controlling flow to the shock absorbers;

a second switch valve in communication with the first switch valve for controlling flow only to the first and second shock absorbers;

a third switch valve in communication with the first switch valve for controlling flow only to the third and fourth shock absorbers;

first and second controlled restriction devices in communication with the first and second shock absorbers, respectively, and with the second switch valve, for assisting in controlling flow to the first and second shock absorbers; and

second and third accumulators in direct communication with the first accumulator, and in communication with the first and second shock absorbers.

16. The hydraulic actuator circuit of claim 15 , further comprising fourth and fifth accumulators in direct communication with the first accumulator, and in communication with the third and fourth shock absorbers.

17. The hydraulic actuator circuit of claim 15 , further comprising third and fourth controlled restriction devices in communication with the third and fourth shock absorbers, respectively, and with the third switch valve, for assisting in controlling flow to the third and fourth shock absorbers.