Compressible fluid independent active suspension

• US 7,740,256 B2
• Filed: 10/25/2005
• Issued: 06/22/2010
• Est. Priority Date: 10/25/2004
• Status: Active Grant

• Current Assignee: Horstman, Inc.
• Original Assignee: Horstman, Inc.
• Inventors: Davis, Leo W.
• Primary Examiner(s): Ilan; Ruth
• Application Number:
  US11/666,316
• Publication Number:
  US 20080111324A1
• Time in Patent Office: 1,701 Days
• Field of Search: 280/124.157, 280/124.16, 267/64.15, 267/64.25, 267/64.26, 188/313, 188/316, 188/317, 188/319.1, 188/322.15, 188/304
• US Class Current: 280/124.157
• CPC Class Codes: B60G 11/26 having fluid springs only, e.g. hydropneumatic springs B60G11/006, B60G15/12 take precedence
• CPC Class Codes: B60G 13/10 pneumatic
• CPC Class Codes: B60G 17/04 fluid spring characteristics
• CPC Class Codes: B60G 17/056 Regulating distributors or valves for hydropneumatic systemsB60G17/044 - B60G17/048, B60G17/0416 take precedence; Fluid interconnection systems to control vehicle inclination B60G21/06, B60G21/10; valves per se F16K
• CPC Class Codes: B60G 17/06 Characteristics of dampers , e.g. mechanical dampersB60G17/015 takes precedence
• CPC Class Codes: B60G 2202/152 Pneumatic spring
• CPC Class Codes: B60G 2202/24 Fluid damper
• CPC Class Codes: B60G 2204/147 on the vehicle engine body
• CPC Class Codes: B60G 2500/2014 Closed systems
• CPC Class Codes: B60G 2500/2041 for variable volume air springs, e.g. using accumulators as expansion chambers
• CPC Class Codes: B60G 3/20 all arms being rigid
• CPC Class Codes: F16F 5/00 Liquid springs in which the liquid works as a spring by compression, e.g. combined with throttling action; Combinations of devices including liquid springs dampers with solid or semi-solid material F16F9/30
• CPC Class Codes: F16F 9/063 comprising a hollow piston rod

Abstract

An active, independent suspension system has dual piston, compressible fluid struts (22). Each of the dual piston struts (22) has an outer cylinder (24) and an outer piston rod (30), which each respectively define exterior peripheries for an outer pressure chamber (32) and an inner pressure chamber (54). Pressures applied to a compressible fluid (56) in respective ones of the outer and inner pressure chambers (32, 54) urge the outer piston to extend from within the outer cylinder (24). A control system (240) is provided for actively controlling an amount of compressible fluid (56) disposed within each of the outer and inner chambers (32, 54).

Claims

1. A compressible fluid independent active suspension comprising:

a plurality of dual piston compressible fluid struts, each of said struts having an outer cylinder and an outer piston rod, said outer cylinder and said outer piston rod respectively defining exterior peripheries for an outer pressure chamber and an inner pressure chamber, wherein pressures applied to a compressible fluid disposed in respective ones of said outer pressure chambers and said inner pressure chambers urge respective ones of said outer pistons to extend from within respective ones of said outer cylinders;

a control system for actively controlling a mass of compressible fluid disposed within each of said outer pressure chambers and said inner pressure chambers of said struts;

a plurality flow lines connecting between said control system and respective ones of said outer pressure chambers and said inner pressure chambers;

wherein said control system selectively controls said mass of compressible fluid within said plurality of dual piston compressible fluid struts, such that said plurality of dual piston compressible fluid struts provide spring function, shock absorber function and active control for said compressible fluid independent active suspension system; and

wherein each of respective ones of said inner pressure chambers and said outer pressure chambers of respective ones of said struts is sealed from being in fluid communication.

2. The compressible fluid independent active suspension system according to claim 1, wherein said control system selectively determines said mass of compressible fluid within said plurality of dual piston compressible fluid struts to determine a spring constant for said plurality of dual piston compressible fluid struts.

3. The compressible fluid independent active suspension system according to claim 2, each of said struts includes a damper member extending from said outer piston rod into said outer cylinder, said damper having flow ports extending there through which are of selected size to dissipate energy absorbed by said suspension system.

4. The compressible fluid independent active suspension system according to claim 3, wherein said independent suspension system is a double A-arm type independent suspension system.

5. A compressible fluid independent active suspension system, comprising:

a dual piston compressible fluid strut having an outer cylinder having a sealed end and an open end, an outer seal assembly sealing said open end of said outer cylinder, an outer piston rod extending through said outer seal assembly and into said outer cylinder, said outer piston rod being moveable into and out of said outer cylinder in response to loading applied to said strut, an inner piston rod, extending from said sealed end of said outer cylinder and into a bore formed into said outer piston rod and an inner seal assembly extending between said inner piston rod and said outer piston rod, and sealingly engaging there-between, wherein said outer piston rod is moveable over said inner piston rod in response to said loading applied to said strut,

a control system for actively controlling a first mass of compressible fluid disposed within said outer cylinder and a second mass of compressible fluid within said outer piston rod of said strut;

a plurality of flow lines connecting between said control system and said outer cylinder and said outer piston rod;

wherein said control system separately controls said first mass of compressible fluid within said outer cylinder and said second mass of compressible fluid within said outer piston rod, such that said dual piston compressible fluid strut provides spring function, shock absorber function and active control for said compressible fluid independent active suspension system for both loaded and unloaded conditions; and

wherein the first mass of compressible fluid within the outer cylinder and the second mass of compressible fluid within the outer piston of said strut is sealed from being in fluid communication.

6. The compressible fluid strut according to claim 5, wherein said outer cylinder has at least one fluid flow port for passing a compressible fluid into and for discharging said compressible fluid from within said outer cylinder.

7. The compressible fluid strut according to claim 5, wherein said bore of said outer piston rod has at least one fluid flow port for passing a compressible fluid into and for discharging said compressible fluid from within said bore of said outer piston rod.

8. The compressible fluid strut according to claim 5, wherein said outer cylinder has at least one outer cylinder fluid flow port for passing a compressible fluid into and for discharging said compressible fluid from within said outer cylinder, and said bore of said outer piston rod has at least one inner cylinder fluid flow port for passing a compressible fluid into and for discharging said compressible fluid from within said bore of said outer piston rod.

9. A method for operating an independent active suspension system for providing spring function, shock absorbing function and active control function, the method comprising the steps of:

providing a plurality of dual piston, compressible fluid struts having an outer cylinder and an outer piston rod moveable into and out of the outer cylinder, with an outer seal extending between the outer cylinder and the piston, and an inner piston rod extending from a sealed end of the outer cylinder and into a bore formed into the outer piston rod, within an inner seal extending between said inner piston rod and said outer piston rod;

disposing a compressible fluid within the outer cylinder and within the outer piston rod, such that movement of the outer piston rod into the cylinder compresses the compressible fluid within the outer cylinder and the outer piston rod;

controlling a first mass of compressible fluid within the outer cylinder to determine a first spring function for the first mass of fluid in the dual piston compressible fluid strut, and thereby at least in part determine dampening forces within the dual piston compressible fluid strut;

separately controlling a second mass of compressible fluid within the outer piston to determine a second spring function for the second mass of fluid, and further determine dampening forces within the compressible fluid dual piston strut; and

wherein each of respective ones of the first mass of compressible fluid within the outer cylinder and the second mass of compressible fluid within the outer piston of respective ones of said struts is sealed from being in fluid communication.

10. The method according to claim 9, further comprising the steps of controlling the rate of energy dissipation within the first mass of compressible fluid by providing a damper element which extends from said piston into said outer chamber, the damper element having flow ports which, when said compressible fluid flows through the flow ports, dissipates energy absorbed by the compressible fluid during a jounce.

11. The method according to claim 9, wherein said mass of compressible fluid within said strut is selectively controlled to provide a dampening force of approximately forty to forty-five percent of a critical dampening force.