Anti-roll system with tilt limitation

• US 5,040,823 A
• Filed: 08/06/1990
• Issued: 08/20/1991
• Est. Priority Date: 08/23/1989
• Status: Expired due to Fees

• Current Assignee: TILT Limitation Control Incorporated, TLC Suspension
• Original Assignee: TILT Limitation Control Incorporated
• Inventors: Lund, Mark A.
• Primary Examiner(s): Rice, Kenneth R.
• Application Number:
  US07/563,048
• Time in Patent Office: 379 Days
• Field of Search: 280/772, 280/112.2, 280/689, 280/707
• US Class Current: 280/5.502
• 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 21/06 fluid
• CPC Class Codes: B60G 2202/24 Fluid damper
• CPC Class Codes: B60G 2204/80 Interactive suspensions; arrangement affecting more than one suspension unit
• CPC Class Codes: B60G 2400/25 Stroke; Height; Displacement
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/40 Steering conditions
• CPC Class Codes: B62D 9/02 combined with means for inwardly inclining vehicle body on bends
• 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 9/512 Means responsive to load action, i.e. static load on the damper or dynamic fluid pressure changes in the damper, e.g. due to changes in velocity F16F9/504, F16F9/516 take precedence; non-automatic damper adjustment from a distance using servo control, the servo pressure being created by the flow of damping fluid F16F9/465; self-pumping fluid springs in vehicle suspensions B60G17/044

Abstract

An anti-roll system for turn compensation in a vehicle generates a differential hydraulic signal in which a pressurizing potential corresponds to a first curve direction and a complementary return hydraulic potential. The system includes a pair of rear wheel cylinder and piston assemblies and a pair of front wheel cylinder and piston assemblies. A hydraulic circuit is connected to conduct the pressurizing potential to move the pistons in a first rear wheel cylinder and piston assembly and a first front wheel cylinder and piston assembly, while conducting the return signal to move the pistons in second front wheel cylinder and piston assembly and a second rear wheel cylinder and piston assembly. A hydraulic conductor directly connects corresponding ends of the rear wheel cylinder and piston assemblies to provide a hydraulic conduction between those assemblies in response to conduction of the differential hydraulic signal. A tilt limitation feature is provided in the front wheel cylinder and piston assemblies and is connected to the hydraulic circuit for limiting the maximum displacement of the pistons in the rear and front wheel cylinder and piston assemblies. In a vehicle, the system reacts to a turn by causing the front and rear wheel cylinder and piston assemblies to tilt the vehicle in a direction to counteract the vehicle rolling force caused by the turn. The tilt-limitation element operates to limit the amount of tilt produced by the system of the invention to counteract vehicle roll force.

Claims

1. A system for roll compensation in a vehicle with front and rear wheels, a vehicle body, a body frame with means for rotatably supporting the wheels, and a suspension connecting the wheels and the body, the system comprising:

valved hydraulic signal means for providing a differential hydraulic signal indicative of vehicle turn direction, the differential hydraulic signal including a pressurizing hydraulic potential and a return hydraulic potential;

a pair of front wheel hydraulic cylinder and piston assemblies connected to the body and the front wheels, each front wheel hydraulic cylinder and piston assembly including upper and lower ports and a piston slidable between the upper and lower ports;

a pair of rear wheel hydraulic cylinder and piston assemblies connected to the body and the rear wheels, each rear wheel hydraulic cylinder and piston assembly including a cylinder with upper and lower ports and a piston slidable in the cylinder between the upper and lower ports;

a first hydraulic means for hydraulically connecting the lower ports of the front wheel hydraulic cylinder and piston assembly to the valved hydraulic signal means;

a second hydraulic means for hydraulically connecting the upper ports of the rear wheel hydraulic cylinder and piston assemblies;

a first hydraulic connection between the upper port of a front wheel hydraulic cylinder and piston assembly connected to a right front wheel and the lower port of a rear wheel hydraulic cylinder and piston assembly connected to a right rear wheel;

a second hydraulic connection between the upper port of a front wheel hydraulic cylinder and piston assembly connected to a left front wheel and the lower port of a rear wheel hydraulic cylinder and piston assembly connected to a left rear wheel; and

tilt limitation means in each of the front wheel hydraulic cylinder and piston assemblies for return conduction of the hydraulic signal in response to cylinder and piston assembly expansion.

2. The anti-roll system of claim 1, further including ported means in the pistons of said rear wheel cylinder and piston assemblies permitting shock displacement of said pistons.

3. The anti-roll system of claim 1, further including ported means in the pistons of said front wheel cylinder and piston assemblies permitting shock displacement of said pistons.

4. The anti-roll system of claim 1, wherein said tilt limitation means includes a port in a front wheel cylinder and piston assembly positioned between the upper and lower ports of said front wheel cylinder and piston assembly and normally covered by the piston of said front wheel cylinder and piston assembly, said port being opened by upward displacement of said piston in response to conduction of said pressurizing potential to the lower port.

5. A cylinder and piston assembly, comprising:

a cylinder with upper and lower ports, each of the ports opening into the interior of the cylinder;

a piston means slidably contained within said cylinder for reciprocal, hydraulically-actuated movement within said cylinder between said ports;

a first piston port opening between each end of said piston, a first flexible port cover attached to a first end of said piston and biased against said first end of said piston to cover one end of said first port, a second piston port opening between each end of said piston, and a second flexible port cover attached to said second end and biased against said second end to cover one end of said second port; and

a floating piston sealing said cylinder beneath said lower port, said floating piston disposed in the interior of said cylinder and attached to said cylinder for reciprocal movement therein about a center line substantially diametrical to said cylinder.

6. The shock absorbing cylinder of claim 5, wherein the floating piston includes:

a substantially cylindrical piece with an annular indentation;

a flexible means disposed in said annular indentation for providing a liquid seal between the floating piston and the interior of the cylinder;

a through-bore extending diametrically through said cylinder; and

a flexible bushing disposed in the diametric bore for flexibly seating the floating piston in the cylinder.

9. The anti-roll system of claim 6 wherein each of said front wheel cylinder and piston assemblies includes a cylinder with upper and lower ports connected to the hydraulic circuit for conducting said hydraulic signal, a moveable piston in the cylinder, and a position-sensing port between said upper and lower ports, the moveable piston being in a first position closing said position sensing port to said upper and lower ports and moving to a second position opening said position sensing port to said upper port or said lower port in response to said pressurizing hydraulic potential.

7. A system for roll compensation in a vehicle having front and rear wheels, a frame with means for rotatably supporting said wheels, a vehicle body, and a suspension connecting the wheels to the body, said system comprising:

valved hydraulic signal means for providing a differential hydraulic signal indicative of vehicle turn direction, the differential hydraulic signal including a pressurizing hydraulic potential and a return hydraulic potential;

a pair of rear wheel hydraulic cylinder and piston assemblies acting between said body and said rear wheels;

a pair of front wheel hydraulic cylinder and piston assemblies acting between said body and said front wheels;

a hydraulic circuit connected to said valved hydraulic signal means and to said rear wheel and front wheel cylinder and piston assemblies for conducting said differential hydraulic signal to said rear wheel and front wheel cylinder and piston assemblies by providing said pressurizing hydraulic potential to move the piston in a first front wheel cylinder and piston assembly while providing the return potential to move the piston in a second front wheel cylinder and piston assembly; and

tilt limitation means connected to the hydraulic circuit and the front wheel cylinder and piston assemblies for limiting the maximum displacement of the pistons in said front wheel cylinder and piston assemblies by return conduction of said pressurizing hydraulic potential.

8. The anti-roll system of claim 7, further including ported means in the pistons of said rear wheel and front wheel cylinder and piston assemblies for permitting shock displacement of said pistons.

16. The system of claim 7, further including a hydraulic conductor directly connecting corresponding ends of said rear wheel cylinder and piston assemblies for hydraulically conducting between said rear wheel cylinder and piston assemblies in response to said differential hydraulic signal.

17. The system of claim 16, further including an accumulator in said hydraulic conductor, the accumulator comprising a substantially cylindrical device having a mid-section with a first diameter and two end sections, each of the end sections having a diameter less than the first diameter, and a flexible, air-filled bladder disposed in the mid-section.

18. The system of claim 17, further including in the fluid circuit means, a back-pressure valve including a first port for connection to a pressurizing fluid potential, a second port for connection to a return fluid potential, and a substantially cylindrical, hollowed out mid-section between said first and second ports, and a spring-loaded internal valve disposed in said mid-section and biased against said first port.

10. A system for roll compensation in a vehicle having a body, wheels, and a suspension connecting the body and the wheels, the system comprising:

a first cylinder and piston assembly attached to the vehicle between the body and a wheel on a first side of the vehicle, the first cylinder and piston assembly including upper and lower fluid ports;

a second cylinder and piston assembly attached to the vehicle between the body and a wheel on a second side of the vehicle, the second cylinder and piston assembly including upper and lower fluid ports;

a fluid circuit means attached to the upper and lower fluid ports of the first and second cylinder and piston assemblies and responsive to a vehicle turn for conducting fluid to compress or expand the first and second cylinder and piston assemblies;

a first position-sensing port means in the first cylinder and piston assembly between the upper and lower ports and connected to the fluid circuit means for conducting fluid to the fluid circuit means from the first cylinder and piston assembly in response to compression or expansion of the first cylinder and piston assembly by conduction of fluid; and

a second position-sensing port means in the second cylinder and piston assembly between the upper and lower ports and connected to the fluid circuit means for conducting fluid to the fluid circuit means from the second cylinder and piston assembly in response to compression or expansion of the second cylinder and piston assembly by conduction of fluid.

11. The system of claim 10, wherein the first cylinder and piston assembly includes a moveable piston and said position-sensing port means of the first cylinder and piston assembly includes a position-sensing port between the upper and lower ports, the moveable piston being in a first position closing the position-sensing port to said upper and lower ports and moving to a second position opening the position-sensing port to the upper or lower port in response to conduction of fluid into the first cylinder and piston assembly.

12. The system of claim 10, wherein the second cylinder and piston assembly includes a moveable piston and said position-sensing port means of the second cylinder and piston assembly includes a position-sensing port between the upper and lower ports, the moveable piston being in a first position closing the position-sensing port to said upper and lower ports and moving to a second position opening the position-sensing port to the upper or lower port in response to conduction of fluid into the second cylinder and piston assembly.

13. A system for roll compensation in a vehicle having a body, wheels, and a suspension connecting the body and wheels, the system comprising:

a plurality of cylinder and piston assemblies, each cylinder and piston assembly including a cylinder with a first and second port, and a piston slidable in the cylinder between the first and second ports;

a first pair of cylinder and piston assemblies being attached to one side of the vehicle, each of the first pair being attached between the body and a respective wheel on said one side of said vehicle;

a second pair of cylinder and piston assemblies being attached to a second side of the vehicle, the second side being opposite the first side, each of the second pair being attached between the body and a respective wheel on said second side of said vehicle;

a fluid circuit means connected to the first and second ports of the plurality of cylinder and piston assemblies for providing a differential fluid signal with pressurizing and return components for alternately compressing and expanding the plurality of cylinder and piston assemblies by conduction of the fluid signal to the cylinder and piston assemblies in response to a vehicle turn;

in one cylinder and piston assembly of the first pair of cylinder and piston assemblies, a position-sensing port in the cylinder between the first and second ports of the cylinder and piston assembly and connected to the fluid circuit means for returning fluid from the cylinder and piston assembly to the fluid circuit means in response to compression or expansion of the cylinder and piston assembly; and

in one cylinder and piston assembly of the second pair of cylinder and piston assemblies, a position-sensing port in the cylinder between the first and second ports of the cylinder and piston assembly and connected to the fluid circuit means for returning fluid from the cylinder and piston assembly to the fluid circuit means in response to compression or expansion of the cylinder and piston assembly.

14. The system of claim 13, wherein a piston in said one cylinder of the first pair of cylinder and piston assemblies being in a first position closing the position-sensing port, and moving to a second position opening the position-sensing port to the first or the second port of the cylinder and piston assembly in response to the differential fluid signal.

15. The system of claim 13, wherein the piston of the one cylinder and piston assembly of the second pair of cylinder and piston assemblies being in a first position closing the position-sensing port, and moving to a second position opening the position-sensing port to the first or second port of the cylinder and piston assembly in response to the differential fluid signal.

19. In a hydraulic suspension system for a vehicle, a device for accumulating hydraulic surges, the device including:

a substantially cylindrical portion with a mid-section having a first diameter, an internal chamber in the mid-section, and a pair of ports opening into the internal chambers; and

a flexible, gas-filled bladder disposed in said mid-section.