Active suspension system and hydraulic ram therefor

• US 8,573,605 B2
• Filed: 02/16/2010
• Issued: 11/05/2013
• Est. Priority Date: 02/16/2009
• Status: Expired due to Fees

• Current Assignee: Phillip Di Maria
• Original Assignee: Phillip Di Maria
• Inventors: Di Maria, Phillip
• Primary Examiner(s): Ilan, Ruth
• Application Number:
  US13/201,756
• Publication Number:
  US 20120119454A1
• Time in Patent Office: 1,358 Days
• Field of Search: 280/5, 280 5506- 5508, 280/5.515, 280/124.106, 280/124.16
• US Class Current: 280/5.506
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 17/01925 Pendulum-type devices
• CPC Class Codes: B60G 17/08 Characteristics of fluid dampers adjusting fluid dampers in general F16F9/44 - F16F9/53
• CPC Class Codes: B60G 21/067 between wheels on different axles on the same side of the vehicle, i.e. the left or the right side
• CPC Class Codes: B60G 2202/413 Hydraulic actuator
• CPC Class Codes: B60G 2204/81 front and rear unit
• CPC Class Codes: B60G 2204/8304 using a fluid
• CPC Class Codes: B60G 2206/41 Dampers
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2401/27 Gravitational, e.g. pendulum or axial movement type
• CPC Class Codes: B60G 2500/02 Supply or exhaust flow rates; Pump operation
• CPC Class Codes: B60G 2500/11 Damping valves
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: F16F 9/504 Inertia , i.e. acceleration,-sensitive means
• CPC Class Codes: F16F 9/5126 Piston, or piston-like valve elements F16F9/504 takes precedence

Abstract

An active suspension system for a vehicle including at least one fluid operated ram having a cylinder and a main piston mounted therein for reciprocating movement, control means for controlling an equilibrium position of the piston in the ram in response to lateral acceleration of the vehicle in order to counter the effects of body roll of the vehicle, and wherein the ram includes shock absorbing means for permitting rapid movement of the piston from the equilibrium position when operating fluid in the ram is subjected to transient increases in pressure.

Claims

1. An active suspension system for a vehicle including at least one fluid operated ram having a cylinder and a main piston mounted therein for reciprocating movement, control means for controlling an equilibrium position of the piston in the ram in response to lateral acceleration of the vehicle in order to counter the effects of body roll of the vehicle, the ram including shock absorbing means including upper and lower internal sealing members mounted within the main piston for permitting rapid movement of the piston from said equilibrium position when operating fluid in the ram is subjected to transient increases in pressure, wherein the main piston includes a main body, and upper and lower parts fitted to the main body, the upper internal sealing member fitted to rest in a sealing configuration against an inner surface of the upper part and being arranged such that an upper surface thereof is in direct communication with an upper working chamber above the main piston and a lower surface thereof is in direct communication with a lower working chamber below the main piston, the lower internal sealing member fitted to rest in a sealing configuration against an inner surface of the lower part and being arranged such that an upper surface thereof is in direct communication with the upper working chamber and a lower surface thereof is in direct communication with the lower working chamber, whereby a transient increase in pressure in the upper working chamber causes the upper internal sealing member to move away from said sealing configuration against the upper part to allow fluid to flow from the upper working chamber to the lower working chamber, and a transient increase in pressure in the lower working chamber causes the lower internal sealing member to move away from said sealing configuration against the lower part to allow fluid to flow from the lower working chamber to the upper working chamber, wherein the main piston is provided with an internal cylinder having a pair of opposed internal pressure relief pistons mounted for movement within the internal cylinder, wherein an upper one of the pressure relief pistons is adapted to exert pressure upwardly against the upper sealing member, and a lower one of the pressure relief pistons is adapted to exert pressure downwardly against the lower sealing member.

2. An active suspension system as claimed in claim 1, wherein the sealing members are in the form of diaphragms.

3. An active suspension system as claimed in claim 1, wherein a resilient means acts between the upper and lower internal sealing members to bias the sealing members toward their sealing configurations.

4. An active suspension system as claimed in claim 3, wherein the resilient means is in the form of a wave washer.

5. An active suspension system as claimed in claim 1, wherein the main piston is provided with a control duct for supplying operating fluid at a control pressure between the upper and lower pressure relief pistons, and the control pressure is able to be varied to adjust a force exerted by the upper and lower pressure relief pistons against the upper and lower sealing members.

6. An active suspension system as claimed in claim 5, wherein the system is adapted such that the control pressure is increased with an increase in lateral acceleration of the vehicle so as to provide a harder rate of shock absorption during cornering.

7. An active suspension system as claimed in claim 6, wherein the upper and lower pressure relief pistons are together in direct abutment when the vehicle experiences substantially nil lateral acceleration, and wherein the pressure relief pistons move apart toward the respective sealing members in response to an increase in the control pressure as lateral acceleration of the vehicle increases.

8. An active suspension system as claimed in claim 7, wherein each of the pressure relief pistons has an abutting surface of reduced cross-section, such that the abutting surfaces are spaced from a wall of the internal cylinder to allow the fluid from the control duct to act on the pressure relief pistons to drive the pistons outwardly one away from the other.

9. An active suspension system as claimed in claim 8, wherein the main piston is provided with a piston ring for sealing of the upper and lower working chambers against a wall of the ram cylinder, and wherein the control duct is arranged to supply fluid at the control pressure to an inner surface of the piston ring so as to assist in ensuring sealing contact between the piston ring and the ram cylinder.

10. An active suspension system as claimed in claim 9, wherein the control duct supplies fluid to the inner surface of the piston ring via the internal cylinder, and, when the pressure relief pistons are together in direct abutment, around the pressure relief pistons through a passage provided by the reduced cross-section of the abutting surfaces.

11. An active suspension system as claimed in claim 9, wherein the upper part is fitted in sleeved arrangement over the main body, and a rim of the upper part terminates in an edge which is located in situ so as to hold the piston ring against a circumferential ledge of the main body.

12. An active suspension system as claimed in claim 1, wherein the upper part has apertures in an upper surface thereof to allow direct communication between the upper working chamber and the upper sealing member, and wherein the lower part has apertures in a lower surface thereof to allow direct communication between the lower working chamber and the lower sealing member.

13. An active suspension system as claimed in claim 12, wherein the apertures are arranged in an evenly spaced annular configuration about a central axis of the ram.

14. An active suspension system as claimed in claim 1, wherein a first damping duct provides permanent communication between the upper sealing member and the lower working chamber, and a second damping duct provides permanent communication between the lower sealing member and the upper working chamber.

15. An active suspension system as claimed in claim 14, wherein the main piston is provided with a plurality of internal cylinders evenly spaced about the central axis of the ram, a plurality of first damping ducts evenly spaced about the central axis, and a plurality of second damping ducts evenly spaced about the central axis.

16. An active suspension system as claimed in claim 15, wherein the main piston is provided with three each of internal cylinders, first damping ducts, and second damping ducts.

17. An active suspension system as claimed in claim 1, wherein said at least one ram includes coupling means to couple the ram between the vehicle chassis and an axle assembly thereof and wherein said at least one ram constitutes a shock absorber for the suspension system.

18. An active suspension system as claimed in claim 17 wherein the vehicle has a plurality of wheels each being connected to the vehicle chassis by one of said axle assemblies and wherein one of said rams is coupled between the vehicle chassis and respective axle assemblies.

19. An active suspension system as claimed in claim 18 wherein the vehicle is an automobile having front and rear driver side wheels and front and rear passenger side wheels and wherein there are front and rear driver side rams and front and rear passenger side rams and wherein the control means is operable to cause the driver side rams to simultaneously move to a first equilibrium position in one sense when the vehicle is cornering in one direction and to cause the passenger side rams to simultaneously move to a second equilibrium position in another sense, opposite to said one sense, when the vehicle is cornering in another direction, opposite to said one direction.

20. A vehicle having an active suspension system as defined in claim 1.

21. An hydraulic ram which can be used as an adjustable shock absorber, said ram having a cylinder, a main piston mounted on a piston rod and defining upper and lower working chambers in the cylinder;

the ram including shock absorbing means including upper and lower internal sealing members mounted within the main piston for permitting rapid movement of the piston from said equilibrium position when operating fluid in the ram is subjected to transient increases in pressure, wherein the main piston includes a main body, and upper and lower parts fitted to the main body, the upper internal sealing member fitted to rest in a sealing configuration against an inner surface of the upper part and being arranged such that an upper surface thereof is in direct communication with the upper working chamber above the main piston and a lower surface thereof is in direct communication with the lower working chamber below the main piston, the lower internal sealing member fitted to rest in a sealing configuration against an inner surface of the lower part and being arranged such that an upper surface thereof is in direct communication with the upper working chamber and a lower surface thereof is in direct communication with the lower working chamber, and wherein a control fluid duct is provided in said piston rod in communication with passages in the main piston to provide fluid communication between said fluid control duct and upper and lower pressure relief pistons mounted within an internal cylinder of the main body to exert sealing force against the upper and lower sealing members, wherein the arrangement is such that hydraulic fluid supply means can be used to supply operating fluid at a high pressure and a low pressure to said upper and lower working chambers whereby the pressure difference across the main piston enables the ram to support a load and wherein the high pressure is, in use, applied to said control fluid duct so that the upper and lower sealing members are in a sealed configuration but, if a transient increase of fluid pressure is caused in the upper working chamber the upper internal sealing member is transiently displaced from said sealing configuration against the upper part to allow fluid to flow from the upper working chamber to the lower working chamber, and if a transient increase of fluid pressure is caused in the lower working chamber the lower internal sealing member is transiently displaced from said sealing configuration against the lower part to allow fluid to flow from the lower working chamber to the upper working chamber.

22. A vehicle having an active suspension system including a fluid operating ram, wherein the fluid operated ram thereof comprises a hydraulic ram as defined in claim 21.