Hydraulic suspension unit

• US 6,086,060 A
• Filed: 08/02/1999
• Issued: 07/11/2000
• Est. Priority Date: 08/02/1996
• Status: Expired due to Fees

• Current Assignee: Brian D. Berthold
• Original Assignee: Brian D. Berthold
• Inventors: Berthold, Brian D.
• Primary Examiner(s): Graham, Matthew C.
• Assistant Examiner(s): BARTZ, CLIFFORD T
• Application Number:
  US09/365,165
• Time in Patent Office: 344 Days
• Field of Search: 188/311, 188/313, 188/297, 188/282, 188/281, 188/279, 188/289, 188/312, 188/322.13, 188/319, 188/299, 267/64.15, 267/64.19, 267/64.23, 280/710, 280/708, 280/784, 280/698, 280/702, 280/712
• US Class Current: 267/64.15
• CPC Class Codes: B60G 11/30 having pressure fluid accumulator therefor, e.g. accumulator arranged in vehicle frame dampers accumulating utilisable energy B60G13/14
• CPC Class Codes: B60G 17/0416 regulated by varying the resiliency of hydropneumatic suspensions B60G17/048 takes precedence
• CPC Class Codes: B60G 17/0424 by varying the air pressure of the accumulator
• CPC Class Codes: B60G 2206/422 Accumulators for hydropneumatic springs
• CPC Class Codes: B60G 2500/11 Damping valves
• CPC Class Codes: B60G 2500/2062 by varying the air-pressure of the accumulator
• CPC Class Codes: F16F 9/003 Dampers characterised by having pressure absorbing means other than gas, e.g. sponge rubber
• CPC Class Codes: F16F 9/06 using both gas and liquid F16F9/486 take precedence; self-pumping fluid springs B60G17/044
• CPC Class Codes: F16F 9/446 Adjustment of valve bias or pre-stress F16F9/443 takes precedence
• CPC Class Codes: F16F 9/516 resulting in the damping effects during contraction being different from the damping effects during extension , i.e. responsive to the direction of movement F16F9/504 takes precedence

Abstract

An improved hydraulic suspension unit has a springing force and rebound damping which are related to one another so as to allow certain wheel movements to occur without the resistance of rebound damping. A primary springing force provided by a pressurized gas, a coil spring, an elastomer or any combination thereof acts directly through the shock fluid via a floating piston, bladder or flexible diaphragm. The primary spring force acts directly through the fluid, and thus directly on a rebound damping valve so that the rebound damping valve is only able to dampen the stored energy of the spring, allowing other extension movements of the suspension unit to take place undamped, if these movements are not caused by the spring returning stored energy. The spring provides a maximum in tuning and adjustment capability for varying conditions with easily variable reload and rate. The rebound damping valve can also be adjusted, both to determine the maximum rebound resistance when damping springing energy, and thus maximum shock shaft velocity, and to determine the magnitude of the shaft movements that are allowed to occur without rebound damping.

Claims

1. A hydraulic suspension unit comprising:

a shock body having a first, interior chamber containing hydraulic liquid;

a shock shaft arranged in telescoping relation with said shock body at one end of said first, interior chamber for relative movement with respect to said body along a longitudinal axis of said suspension unit with changes in force on said suspension unit compressing and extending said suspension unit, the volume of said chamber being decreased and increased with relative movement of the shaft and body in compressing and extending said suspension unit, respectively, said hydraulic liquid in said chamber being in compressive force transmitting relation between said shock body and said shaft;

a reservoir spaced from said chamber and containing hydraulic liquid;

a first passage connecting said chamber and said reservoir to permit the flow of hydraulic liquid from said chamber to said reservoir during compressing of said suspension unit;

a second passage connecting said chamber and said reservoir to permit the flow of hydraulic liquid from said reservoir to said chamber during extending of said suspension unit, said reservoir including a movable wall which can be moved back and forth to increase and decrease the volume of said reservoir as a function of the volume of hydraulic liquid flowing to and from said reservoir, respectively;

a spring means for resiliently biasing said movable wall against the hydraulic liquid in said reservoir with a force which is a function of the amount of movement of said spring means and in turn the position of the said movable wall and volume of said reservoir, said spring means storing energy upon movement of said movable wall increasing the volume of said reservoir with the flow of hydraulic liquid to said reservoir and said spring means releasing said stored energy upon movement of said movable wall, decreasing the volume of the said reservoir with the flow of hydraulic liquid from said reservoir to said first chamber;

compression damping means for damping the flow of hydraulic liquid through said first passage from said first chamber to said reservoir when said suspension unit is compressed to cause relative movement of said first and second members toward one another along said longitudinal axis decreasing the volume of said first chamber;

means for adjusting an amount of compression damping provided by said compression damping means without resort to physically changing components of said suspension unit; and

rebound damping means for limiting the rebound velocity of the initially compressed suspension unit to a first value when such velocity is due to the force imparted by the spring means when it is returning stored energy after some initial compression, said rebound damping means damping the flow of hydraulic liquid through said second passage to said first chamber from said reservoir resulting from said spring means releasing energy stored therein by moving said movable wall to decrease the volume of said reservoir and flow hydraulic liquid from said reservoir to said first chamber for extending said suspension unit, while said rebound damping means and said suspension unit at the same time not necessitating flow of hydraulic liquid out of said first chamber when extending said suspension unit as said first chamber volume increases during extension of said suspension unit to permit a higher rebound velocity than said first value when extending said suspension unit by external forces on said suspension unit.

2. The hydraulic suspension unit according to claim 1, wherein said means for adjusting an amount of compression damping of said compression damping means adjusts the force required to initiate compression of the suspension unit.

3. The hydraulic suspension unit according to claim 1, wherein said means for adjusting an amount of compression damping of said compression damping means adjusts the maximum velocity allowed during compression of said suspension unit.

4. The hydraulic suspension unit according to claim 1, wherein said first passage directs all of the flow of hydraulic liquid from said first chamber during compressing of the suspension unit to said reservoir via said compression damping means and said second passage directs all of the flow of the hydraulic liquid from the reservoir to the first chamber via said rebound damping means during extending of the suspension unit.

5. A hydraulic suspension unit comprising:

a shock body having a first, interior chamber containing hydraulic liquid;

a shock shaft arranged in telescoping relation with said shock body at one end of said first, interior chamber for relative movement with respect to said body along a longitudinal axis of said suspension unit with chances in force on said suspension unit compressing and extending said suspension unit, the volume of said chamber being decreased and increased with relative movement of the shaft and body in compressing and extending said suspension unit, respectively, said hydraulic liquid in said chamber being in compressive force transmitting relation between said shock body and said shaft;

a reservoir spaced from said chamber and containing hydraulic liquid;

a first passage connecting said chamber and said reservoir to permit the flow of hydraulic liquid from said chamber to said reservoir during compressing of said suspension unit;

a second passage connecting said chamber and said reservoir to permit the flow of hydraulic liquid from said reservoir to said chamber during extending of said suspension unit, said reservoir including a movable wall which can be moved back and forth to increase and decrease the volume of said reservoir as a function of the volume of hydraulic liquid flowing to and from said reservoir, respectively;

a spring means for resiliently biasing said movable wall against the hydraulic liquid in said reservoir with a force which is a function of the amount of movement of said spring means and in turn the position of the said movable wall and volume of said reservoir, said spring means storing energy upon movement of said movable wall increasing the volume of said reservoir with the flow of hydraulic liquid to said reservoir and said spring means releasing said stored energy upon movement of said movable wall, decreasing the volume of the said reservoir with the flow of hydraulic liquid from said reservoir to said first chamber;

compression damping means for damping the flow of hydraulic liquid through said first passage from said first chamber to said reservoir when said suspension unit is compressed to cause relative movement of said first and second members toward one another along said longitudinal axis decreasing the volume of said first chamber;

means for adjusting an amount of compression damping provided by said compression damping means without resort to physically changing components of said suspension unit; and

rebound damping means for limiting the rebound velocity of the initially compressed suspension unit to a first value when such velocity is due to the force imparted by the spring means when it is returning stored energy after some initial compression, said rebound damping means damping the flow of hydraulic liquid through said second passage to said first chamber resulting from said spring means releasing energy stored therein by moving said movable wall to decrease the volume of said reservoir and flow hydraulic liquid from said reservoir to said first chamber for extending said suspension unit, while said rebound damping means and said suspension unit at the same time permitting a higher rebound velocity than said first value when extending said suspension unit by external forces on said suspension unit,

wherein said compression damping means includes a compression damping valve in the form of a flexible disk which is movable in response to pressure of said hydraulic liquid thereon for opening and closing said first passage for controlling the flow of hydraulic liquid through said first passage from said first chamber to said reservoir during compressing of said suspension unit.

6. The hydraulic suspension unit according to claim 5, wherein said means for adjusting the amount of compression damping applies an adjustable preload on said disk to effect the hydraulic pressure necessary to deflect said disk and open said first passage.

7. The hydraulic suspension unit according to claim 5, wherein said means for adjusting the amount of compression damping includes a mechanical stop limiting the opening extent of said flexible disk, and means for adjusting the position of said stop.