Frequency dependent pressure and/or flow fluctuation mitigation in hydraulic systems

Patent metadata

Field	Value
Publication number	US-11440366-B1
Application number	US-201916590996-A
Country	US
Kind code	B1
Filing date	Oct 2, 2019
Priority date	Oct 3, 2018
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

Active suspension systems including actuators with combinations of accumulators and flow restrictions, as well as their methods of operation, are described. In some embodiments, methods and constructions for mitigating pump ripple and/or resonances between different hydraulic components are also described.

First claim

What is claimed is:

1. An actuator comprising:
a housing including a first volume and a second volume with a piston slidably disposed between the first volume and the second volume;
a hydraulic device fluidly coupled to the first volume and the second volume along a first flow path extending between the first volume and the second volume, wherein in a first operating mode the hydraulic device operates in a first direction and in a second operating mode the hydraulic device operates in a second direction;
an electric motor/generator operatively coupled to the hydraulic device;
a first accumulator disposed along the first flow path between the hydraulic device and the first volume;
a second accumulator disposed along the first flow path between the hydraulic device and the second volume; and
at least one flow restriction located along the first flow path, wherein the at least one flow restriction is configured to damp a flow in the first flow path between the first accumulator and the second accumulator.

2. The actuator of claim 1 , wherein the at least one flow restriction is positioned between the first accumulator and the first volume or the second accumulator and the second volume.

3. The actuator of claim 1 , wherein the at least one flow restriction includes a first flow restriction located between the first accumulator and the first volume and a second flow restriction located between the second accumulator and the second volume.

4. The actuator of claim 1 , wherein the housing comprises a twin tube housing including an inner tube and a concentrically located outer tube wherein the at least one flow restriction is formed by an annular gap between the inner tube and the concentrically located outer tube.

5. The actuator of claim 1 , wherein the at least one flow restriction is constructed and arranged to damp frequencies between or equal to 75 Hz and 150 Hz.

6. The actuator of claim 1 , wherein the first accumulator is a first flow through accumulator.

7. The actuator of claim 1 , wherein the second accumulator is a flow through accumulator.

8. The actuator of claim 1 , wherein the second accumulator is a single port accumulator.

9. The actuator of claim 8 , wherein an inlet to the single port accumulator is constructed and arranged to function as a low pass filter.

10. The actuator of claim 9 , wherein the inlet to the single port accumulator comprises a shimstack.

11. A vehicle comprising:
an active suspension system including one or more actuators, wherein each actuator comprises:
a housing including a first volume and a second volume with a piston slidably disposed between the first volume and the second volume;
a hydraulic device fluidly coupled to the first volume and the second volume along a first flow path extending between the first volume in the second volume, wherein in a first operating mode the hydraulic device operates in a first direction and in a second operating mode the hydraulic device operates in a second direction;
an electric motor/generator operatively coupled to the hydraulic device;
a second flow path extending between the first volume and the second volume that bypasses the hydraulic device; and
a valve that selectively permits flow through the second flow path based at least partly on the vehicle's speed, wherein the valve permits flow through the second flow path when the vehicle velocity is less than a threshold velocity and prevents flow through the second flow path when the vehicle velocity is greater than the threshold velocity.

12. The vehicle of claim 11 , wherein the threshold velocity is between 20 miles per hour and 30 miles per hour.

13. The vehicle of claim 11 , further comprising at least one flow restriction disposed along the second flow path.

14. The vehicle of claim 13 , further comprising a first accumulator disposed along the first flow path between the hydraulic device and the first volume and a second accumulator disposed along the first flow path between the hydraulic device and the second volume.

15. The vehicle of claim 14 , wherein the at least one flow restriction is constructed to damp a flow between the first accumulator and the second accumulator.

Assignees

• Clearmotion Inc

Inventors

• O'Shea Colin Patrick
• Belter Joseph Thomas
• Selden Brian Alexander

Classifications

• F16F9/512

  Means responsive to load action, {i.e. static load} on the damper or {dynamic} fluid pressure {changes} in the damper, {e.g. due to changes in velocity (F16F9/504, F16F9/516 take precedence; non-automatic damper adjustment from a distance using servo control, the servo pressure being created by the flow of damping fluid F16F9/465; self-pumping fluid springs in vehicle suspensions B60G17/044)} · CPC title

• F16F9/46

  allowing control from a distance {, i.e. location of means for control input being remote from site of valves, e.g. on damper external wall (attachment of valve units to cylinders F16F9/325)} · CPC title

• F16F9/065

  Expansion chamber provided on the upper or lower end of a damper, separately there from or laterally on the damper · CPC title

• B60G2202/416

  using a pump, e.g. in the line connecting the lower chamber to the upper chamber of the actuator · CPC title

• B60G2400/10

  Acceleration; Deceleration · CPC title