Air spring damper for vehicle suspension

• US 4,934,667 A
• Filed: 04/14/1988
• Issued: 06/19/1990
• Est. Priority Date: 08/13/1986
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: McClain, Michael J., Pees, James M.
• Primary Examiner(s): Halvosa, George E. A.
• Assistant Examiner(s): Le, Mark T.
• Application Number:
  US07/181,478
• Time in Patent Office: 796 Days
• Field of Search: 188/322.17, 188/322.18, 188/322.16, 267/64.21, 267/64.17, 267/64.19, 267/64.23, 267/64.24, 267/64.28, 267/64.27, 267/122, 267/124, 267/129
• US Class Current: 267/64.21
• CPC Class Codes: B60G 11/64 having both torsion-bar springs and fluid springs
• CPC Class Codes: B60G 15/14 the damper being connected to the stub axle and the spring being arranged around the damper
• CPC Class Codes: B60G 21/051 Trailing arm twist beam axles
• CPC Class Codes: F16F 9/0409 characterised by the wall structure
• CPC Class Codes: F16F 9/084 comprising a gas spring contained within a flexible wall, the wall not being in contact with the damping fluid, i.e. mounted externally on the damper cylinder
• CPC Class Codes: F16F 9/3228 of connections between pistons and piston rods
• CPC Class Codes: F16F 9/49 Stops limiting fluid passage, e.g. hydraulic stops or elastomeric elements inside the cylinder which contribute to changes in fluid damping fluid-actuated displacement devices with means for accelerating or decelerating the stroke F15B15/22
• CPC Class Codes: F16F 9/50 Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discsF16F9/53 takes precedence; Special means providing self-adjustment of spring characteristics

Abstract

An air spring damper used in a vehicle suspension system with upper, intermediate and lower chambers and incorporating a reservoir tube which has an anti-friction rod guide and bearing assembly therein which lubricates the hollow rod of a piston as it strokes in their reservoir tube in jounce and rebound. An elastomeric air sleeve is featured which is connected to a top mount fastened to the vehicle body. An elastomeric isolator of this mount pivotally connects the piston rod to the body while sealing the upper end of the air sleeve. The air sleeve is supported full time by an outer elastomeric sleeve for improved air sleeve operation. A jounce bumper mounted internal of the reservoir tube is compressible to resist and cushion jounce strokes of the piston. This damper provides optimized vehicle body isolation and damping of both body and wheel axle at their natural frequencies.

Claims

1. An air spring damper for the suspension of a vehicle body with respect to a support for a road wheel and for damping the natural frequency of the road wheel support and the natural frequency of the vehicle body comprising, an elongated reservoir tube having a pressurized air therein, means attaching a lower end portion of said reservoir tube to said road wheel support, a valved piston mounted for reciprocating jounce and rebound stroking movement within said reservoir tube defining intermediate and lower air chambers and restricting the flow of air therethrough to dissipate the energy of the natural frequency of said wheel support and the differing natural frequency of said body, a top mount attached to said body, a piston rod attached to said piston and extending from said reservoir tube into connection with said top mount, elastomeric air spring means having a rolling lobe and defining an upper air chamber extending around said piston rod and operatively mounted between the upper end of said reservoir tube and said top mount for rolling movement thereon, rod guide and rod guide bearing means slidably receiving said piston rod and closing the upper end of said reservoir tube, air passage means within said piston rod and said piston for pneumatically connecting said upper and lower chambers, and means for supplying pressurized air to said air passage means to effect the air spring suspension of said body with respect to said wheel support.

2. The air spring damper of claim 1 and further comprising a resilient outer support sleeve providing full time support of said air spring means including full time circumferential support during jounce and rebound motions.

3. The air spring damper of claim 1 and further comprising retainer means connecting said air spring means to the upper portion of said reservoir tube and piston means mounted over said retainer means and said reservoir tube to define a varying diameter surface for said rolling lobe to change the spring rate of said air spring as said damper moves in jounce and rebound.

4. The air spring damper of claim 1 wherein said piston rod is hollow and pneumatically interconnects said upper and lower chambers so that pressurized air in said upper and lower chambers exerts a lifting force on said piston to supplement the lifting force exerted on said top mount and said body by the pressure in said upper chamber.

5. The air spring damper of claim 1 wherein said valved piston is comprised of a piston shell, an orifice plate housed in said shell and a plurality of valve disks mounted in said orifice plate having inner and outer diameters deflectable to meter and restrict the flow of air through said piston on jounce and rebound stroking movement of said piston.

6. The air spring damper of claim 1 wherein said valved piston includes a piston shell attached to the lower end of said piston rod, a band-like seal carried by said piston shell along the outer periphery thereof for sliding and sealing contact with the inner wall of said reservoir tube, said seal having a skirt portion providing annular contact with the inner wall of said reservoir tube and spring means interposed between said piston shell and said skirt portion for resiliently urging said skirt portion into close annular sealing and sliding contact with said inner wall of the reservoir tube.

7. The air spring damper of claim 1 wherein said rod guide bearing means is a sleeve of sintered bronze and Teflon material and wherein said Teflon has molecules aligned with the direction of rod travel to reduce sliding friction.

8. The air spring damper of claim 1, wherein said rod guide and rod guide bearing means have flared upper and lower openings to accommodate rocking of said piston rod during jounce and rebound action of the damper and said rod guide bearing means is a sleeve pressed into said rod guide and has a sintered bronze and Teflon coating material on the inner wall thereof to provide improved anti-friction sliding engagement with said rod by liquefying when the bronze heats to a predetermined temperature from frictional sliding engagement with said piston rod.

9. The air spring damper of claim 1 wherein said top mount includes an elastomeric annulus which isolates the piston rod from the body and pivotally connects said piston rod to the body, and clamping means securing said air spring means to said top mount to seal the top of the air spring means and rate washer means carried by said piston for contact with said annulus to cushion the last travel of the damper in rebound.

10. An air spring damper for the suspension of a vehicle body with respect to a support for a road wheel and for damping the natural frequency of the road wheel support and the lower natural frequency of the vehicle body comprising, an elongated reservoir tube having a pressurized air therein, means attaching a lower end portion of said reservoir tube to said road wheel support, a piston mounted for reciprocating jounce and rebound stroking movement within said reservoir tube, valve disk means operatively mounted in said piston and deflectable to restrict the flow of air therethrough to optimize damping of the natural frequency of said wheel support and provide diminishing dissipation of energy of wheel support frequency beyond said natural frequency and to further damp the lower natural frequency of said body, a piston rod attached to said piston and extending from said reservoir tube, elastomeric air spring means operatively mounted above said reservoir tube for rolling movement thereon, rod guide and rod guide bearing means slidably receiving said piston rod and closing the upper end of said reservoir tube, passage means within said piston rod for admitting pressurized air to said air spring means and said reservoir tube to effect the air spring suspension of said body with respect to said wheel support, and said passage means interconnecting the air spring means and said reservoir tube.

11. The air spring damper of claim 10 and further comprising an elastomeric outer support sleeve contacting the outer periphery of said elastomeric air spring means providing full time support of said air spring means including jounce and rebound motion

12. The air spring damper of claim 10 and further comprising an upper mount with an elastomeric isolator connecting said piston rod to said body to vibrationally isolate said piston rod from said body and to serve as a pivot for said piston rod and to provide an upper seal for said air spring means.

13. The air spring damper of claim 10 wherein said reservoir attaching means is a base cup and further comprising a jounce bumper of a compressible and resilient material mounted in said reservoir tube below said piston to provide increasing resistance to jounce and constrictable into said base cup connecting said reservoir tube to said wheel support at full jounce.

14. An air spring damper for the suspension of a vehicle body with respect to a support for a road wheel and for damping the natural frequency of the road wheel support structure and the natural frequency of the vehicle body comprising, an elongated reservoir tube having a pressurized air therein, base cup means attaching a lower end portion of said reservoir tube to said road wheel support a valved piston mounted for reciprocating stroking movement within said reservoir tube during jounce and rebound strokes and restricting the flow of air therethrough to dissipate the energy of the natural frequency of said wheel support and the differing natural frequency of said body, a piston rod attached to said piston and extending from said reservoir tube, cylindrical elastomeric air spring means operatively mounted above said reservoir tube for rolling movement thereon, rod guide and rod guide bearing means slidably receiving said piston rod and closing the upper end of said reservoir tube, air passage means in said piston rod for admitting pressurized air to said air spring means and said reservoir tube to effect the air spring suspension of said body with respect to said wheel support, and said passage means interconnecting the air spring means and said reservoir tube.

15. The air spring damper of claim 14 and further comprising a resilient outer support sleeve providing full time diametrical support of said air spring means including jounce and rebound motion.

16. The air spring damper of claim 14 in which said rod guide bearing is a lubricating thin-walled tubular sleeve pressed into said rod guide to provide lubricated support of said piston rod as it moves in jounce and rebound.

17. The air spring damper of claim 14 and further including an elastomeric upper mount connected to said vehicle body and preloaded between upper and lower supports affixed to said piston rod.

18. A suspension device for a vehicle comprising:

(a) a damper having relatively movable telescopic parts including a rigid tubular member and a piston assembly mounted for stroking movement therein, a piston rod connected to said piston assembly and extending therefrom and through one end of said tubular member,

(b) a resilient tubular rolling-lobe air spring member disposed around at least a part of the length of the rigid tubular member, said air spring having

i a tubular inner wall portion with a first terminal end that defines a lower extremity of said air spring member,

ii and a tubular outer wall portion spaced from the inner wall portion with a second terminal end that defines an upper extremity of said air spring member, and

iii a rolling lobe portion interconnecting said inner and outer wall portions, said rolling lobe portion being movable on reciprocal movement of said piston and piston rod relative to said rigid tubular member,

(c) first fastener means securing said first terminal end of said tubular inner wall in an air tight manner with respect to said rigid tubular member,

(d) second fastener means securing said second terminal end of said tubular outer wall in an air tight manner with respect to said piston rod so that said air spring member forms a closed fluid pressure receiving chamber surrounding a major part of said damper for receiving air under pressure to thereby provide an air spring, said air spring yieldably resisting telescopic movement of said damper on admission of fluid pressure into said chamber,

(e) fluid supply means for supplying pressure to and from said chamber, and

(f) a radially resilient support tube having full time contact with said outer wall portion of said air spring member for the radial support thereof, said support tube including a lower constricted end portion which has a diameter less than the diameter of said tubular outer wall portions, said support tube terminating in a first end secured adjacent said second fastening means and in a second end extending beyond the travel range of said rolling lobe portion and remaining substantially undeflected to support an outer surface of said rolling lobe portion.

21. The suspension device as specified in claim 18 wherein the support tube second end is undeflected.

22. The suspension device as specified in claim 18 wherein the support tube is formed from a fabric reinforced radially elastomeric material.

23. The suspension device as specified in claim 22 wherein the air spring member outer wall is formed from a fabric reinforced radially elastomeric material.

24. The suspension device as specified in claim 23 wherein the fabric cord angle of the support sleeve is less than the fabric cord angle of the air spring member outer wall.

25. The suspension device as specified in claim 24 wherein the fabric cord angle of the support sleeve is approximately 20 degrees.

26. The suspension device as specified in claim 24 wherein the fabric cord angle of the air spring member is approximately 60 degrees.

27. The suspension device as specified in claim 18 including piston means adapted about the upper circumference of the rigid tubular member over the second fastener means to define a varying diameter for receiving the rolling lobe portion.

28. The suspension device as specified in claim 27 wherein the piston means is formed from a hard plastic material.

19. An air adjustable suspension spring and damper for a vehicle suspension and for operatively interconnecting sprung and unsprung vehicle masses comprising:

(a) support tube means operatively connected to one of said vehicle masses,

(b) a valved piston assembly mounted within the confines of said support tube means for stroking movement therein to restrict the flow of working fluid therethrough and thereby control the spring action of the vehicle suspension,

(c) piston rod means connected to said piston assembly and extending therefrom through at least one end of said support tube,

(d) a first tubular sleeve of radially resilient material for an air suspension spring,

(e) fastener means operatively connecting said first tubular sleeve at one end thereof in an airtight manners with respect to said support tube means,

(f) mounting means for connecting said piston rod to the other of said vehicle masses,

(g) second fastener means for operatively connecting the other end of said first tubular sleeve to said mounting means,

(h) a second tubular sleeve of radially resilient material including as lower constricted end portion that has a diameter less than the diameter of said first tubular sleeve, said second tubular sleeve having a first end secured with respect to one of said vehicle masses and encompassing a portion of said first tubular sleeve to provide full time engagement and resilient radial support of said first tubular sleeve when said first tubular sleeve is air pressurized and operating as a spring suspension, said second tube having a second end terminating in an undeflected end extending beyond said first tubular sleeve.

29. The air adjustable suspension spring and damper as specified in claim 19 wherein the first and second tubular sleeves are formed from corded elastomeric materials.

30. The air adjustable suspension spring and damper as specified in claim 29 wherein the cord angle of the first tubular sleeve is greater than the cord angle of the second tubular sleeve.

20. An air adjustable suspension spring and a suspension spring damper integrated therewith for operatively interconnecting sprung and unsprung masses of a vehicle comprising:

(a) support tube means operatively connected to one of said vehicle masses,

(b) a valved piston assembly mounted within the confines of said support tube means for stroking movement therein to restrict the flow of working fluid therethrough and thereby control the spring action of the vehicle suspension,

(c) piston rod means connected to said piston assembly and extending therefrom through at least one end of said support tube,

(d) a first tubular sleeve of a radially elastomeric material for an air suspension spring,

(e) fastener means operatively connecting said first tubular sleeve at one end thereof in an airtight manner with respect to said support tube means,

(f) mounting means for connecting said piston rod to the other of said vehicle masses,

(g) second fastener means for operatively connecting the other end of said first tubular sleeve to said mounting means,

(h) a second tubular sleeve of a radially elastomeric material having one end secured with respect to said vehicle mounting means and encompassing a portion of said first tubular sleeve to provide full time engagement and resilient support of said first tubular sleeve when said first tubular sleeve is air pressurized and operating as a spring suspension, said second tube having a second end terminating in an undeflected end extending beyond said first tubular sleeve, said second end having a diameter less than the diameter of the first tubular sleeve.

31. The air adjustable suspension spring and the suspension spring damper as specified in claim 20 including:

(a) a rod guide for the piston rod mounted in an upper end of the support tube means, the rod guide having a bore therein to slidably receive the piston rod means, and

(b) a rod guide bearing fitted in the rod guide, having a cylindrical central section and upper and lower conical end sections, the upper and lower end sections extending from communication under the central section to enlarged diameter openings to receive and support the piston rod means during a rocking movement thereof relative to the rod guide.

32. The air adjustable suspension spring and suspension sprig damper as specified in claim 20 including:

(a) a skirt-like annular seal wrapper around the piston assembly, and

(b) spring means disposed between the seal and the piston assembly for urging the seal outwardly for close sealing contact with an interior wall of the second tubular sleeve.