Vehicle suspension with a regenerative hydraulic shock-absorber and with a system for adjusting the attitude of the vehicle

Patent metadata

Field	Value
Publication number	US-11072220-B2
Application number	US-201716303518-A
Country	US
Kind code	B2
Filing date	May 23, 2017
Priority date	May 24, 2016
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

A suspension including a spring interposed between the body (B) of the vehicle and the wheel (W); a regenerative hydraulic shock-absorbing unit comprising a hydraulic shock-absorber arranged parallel to the spring, a motor and pump unit with a volumetric hydraulic machine and an electric machine coupled to the hydraulic machine), and an electronic control unit arranged to control the torque of the electric machine. A hydraulic actuator is arranged in series with the spring. A reservoir and a hydraulic circuit are connected to each other, the hydraulic shock-absorber, the hydraulic machine the hydraulic actuator and the reservoir. The hydraulic circuit includes a valve assembly for controlling the flow of a working fluid between the hydraulic shock-absorber, the hydraulic machine, the hydraulic actuator and the reservoir.

First claim

The invention claimed is:

1. A suspension for a wheel (W) of a vehicle, comprising
a spring interposed between a body (B) of the vehicle and the wheel (W), and
a regenerative hydraulic shock-absorbing unit comprising a hydraulic shock-absorber arranged in parallel with the spring, a motor and pump unit with a volumetric hydraulic machine and an electric machine coupled to the hydraulic machine, wherein both the hydraulic machine and the electric machine operate alternatively as a working machine or as a motor, and an electronic control unit arranged to control a torque of the electric machine, whereby the regenerative hydraulic shock-absorbing unit is able to convert part of a vibrational kinetic energy of the suspension into electric energy,
wherein the suspension further comprises
a single-effect hydraulic actuator arranged in series with the spring to control a vertical position of the body (B) relative to the wheel (W),
a reservoir, and
a hydraulic circuit connecting the hydraulic shock-absorber, the hydraulic machine, the hydraulic actuator and the reservoir with each other, the hydraulic circuit comprising a valve assembly for controlling the flow of a working fluid between the hydraulic shock-absorber, the hydraulic machine, the hydraulic actuator and the reservoir so as to enable the suspension to operate selectively in one of the following operating conditions:
a first operating condition, in which the hydraulic actuator is isolated from the reservoir and remains therefore in a fixed position, thereby keeping a distance between the wheel (W) and the body (B) of the vehicle unchanged, and in which the hydraulic shock-absorber is connected to the hydraulic machine to enable the regenerative hydraulic shock-absorbing unit to operate in regenerative mode, that is to say, to convert part of the vibrational kinetic energy of the suspension into electric energy;
a second operating condition, in which the hydraulic actuator is connected to, and supplied by, the hydraulic machine to be extended and thus increase the distance between the wheel (W) and the body (B) of the vehicle, and in which the hydraulic shock-absorber is isolated from the hydraulic machine; and
a third operating condition, in which the hydraulic actuator is connected to the reservoir to be retracted and thus reduce the distance between the wheel (W) and the body (B) of the vehicle, and in which the hydraulic shock-absorber is isolated from the hydraulic machine.

2. The suspension of claim 1 , wherein the hydraulic circuit further comprises a first hydraulic line connected to a first hydraulic communication port of the hydraulic shock-absorber, a second hydraulic line connected to a second hydraulic communication port of the hydraulic shock-absorber, a third hydraulic line connected to the reservoir, and a fourth hydraulic line connected to the hydraulic actuator, and wherein said valve assembly comprises a first flow control valve for controlling the connection of said first, second, third and fourth hydraulic lines with an upper mouth and a lower mouth of the hydraulic machine.

3. The suspension of claim 2 , wherein the first flow control valve is controllable to take selectively a first position, where it puts the upper mouth and the lower mouth of the hydraulic machine in communication with the first and second hydraulic communication ports of the hydraulic shock-absorber, respectively, and closes the third and fourth hydraulic lines, and a second position, where it puts the upper mouth and the lower mouth of the hydraulic machine in communication with the third and fourth hydraulic lines, respectively, and closes the first and second hydraulic lines.

4. The suspension of claim 3 , wherein the first flow control valve is normally kept in the first position.

5. The suspension of claim 3 , wherein the first flow control valve includes a bypass calibrated restrictor which in the second position puts the first and second hydraulic lines in communication with each other.

6. The suspension of claim 2 , wherein said valve assembly further comprises a pressure relief valve arranged along a fifth hydraulic line connecting the third hydraulic line with the fourth hydraulic line to allow the working fluid to be discharged from the actuator to the reservoir if a pressure in the fourth hydraulic line exceeds a given safety value.

7. The suspension of claim 2 , wherein said valve assembly further comprises:
a non-return valve which is arranged along the fourth hydraulic line and is able to allow the working fluid to flow only in a direction from the hydraulic machine to the actuator, when the first flow control valve is in the second position, and
a second flow control valve for controlling the connection between the third hydraulic line and the fourth hydraulic line through a sixth hydraulic line which is connected to the fourth hydraulic line in a point between the actuator and the non-return valve.

8. The suspension of claim 7 , wherein the second flow control valve is a two-way two-position valve which is normally kept in a position in which the second flow control valve prevents the working fluid from flowing through the sixth hydraulic line.

9. The suspension of claim 2 , wherein the hydraulic shock-absorber is a single-tube shock-absorber comprising a cylinder and a piston slidably arranged in the cylinder so as to separate an extension chamber and a compression chamber from each other, wherein the piston is provided with a first non-return valve and a second non-return valve which control the flow of the working fluid between the extension chamber and the compression chamber, the first non-return valve allowing the working fluid to flow only in a direction from the extension chamber to the compression chamber and the second non-return valve allowing the working fluid to flow only in a direction from the compression chamber to the extension chamber, wherein the cylinder slidably receives a movable diaphragm which is placed underneath the piston and separates the compression chamber from a gas chamber containing gas at high pressure, and wherein the first and second hydraulic communication ports of the hydraulic shock-absorber are connected with the extension chamber and the compression chamber, respectively.

10. The suspension of claim 2 , wherein the hydraulic shock-absorber is a three-tube shock-absorber comprising:
a first innermost tube, in which a piston is slidably arranged so as to split the internal volume of the said first tube into an extension chamber and a compression chamber,
a second outermost tube, which is arranged coaxially with the first tube so as to define with the first tube a reservoir chamber,
a third tube which is interposed between the first tube and the second tube, coaxially therewith, and encloses with the first tube an intermediate chamber, wherein the first and second hydraulic communication ports of the hydraulic shock-absorber are connected with the intermediate chamber and the reservoir chamber, respectively, and
wherein the hydraulic shock-absorber is also provided with a third communication port through which the intermediate chamber communicates with the extension chamber.

11. The suspension of claim 10 , wherein the reservoir is formed by the reservoir chamber of the hydraulic shock-absorber only and wherein the third hydraulic line coincides with the second hydraulic line.

12. The suspension of claim 10 , wherein the reservoir comprises the reservoir chamber of the hydraulic shock-absorber and an additional reservoir separate from the reservoir chamber, and wherein the third hydraulic line is connected both to the additional reservoir and to the second hydraulic line.

Assignees

• Sistemi Sospensioni Spa
• Magneti Marelli Spa

Inventors

• Conti Piero Antonio
• Greco Giordano
• Nepote Andrea
• Amati Nicola
• Galluzzi Renato
• Tonoli Andrea

Classifications

• B60G2300/60

  Vehicles using regenerative power · CPC title

• B60G2500/114

  pressure regulating valves · CPC title

• B60G2202/413

  Hydraulic actuator · CPC title

• B60G2202/32

  The spring being in series with the damper and/or actuator · CPC title

• B60G2202/30

  Spring/Damper and/or actuator Units · CPC title