Anti-roll system with tilt limitation

• US 4,966,390 A
• Filed: 08/23/1989
• Issued: 10/30/1990
• Est. Priority Date: 08/23/1989
• Status: Expired due to Fees

• Current Assignee: TILT Limitation Control Incorporated
• Original Assignee: Tilt Limitation Control
• Inventors: Garrabrant, Genevieve, Lund, Mark A.
• Primary Examiner(s): Rice, Kenneth R.
• Application Number:
  US07/397,723
• Time in Patent Office: 433 Days
• Field of Search: 280/772, 280/112.2, 280/684, 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 having front and rear wheels, a frame with means for rotatably supporting said wheels, a vehicle body, and a suspension, said system comprising:

valved hydraulic signal means for providing a differential hydraulic signal indicative of vehicle turn direction, said 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 pistons in a first rear wheel and a first front wheel cylinder and piston assembly while providing said return potential to move the pistons in the second rear wheel and the second front wheel cylinder and piston assemblies;

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 conduction of said differential hydraulic signal to said rear wheel cylinder and piston assemblies; and

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

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

3. The anti-roll system of claim 1 wherein said tilt-limitation means includes a tilt limiter in a front wheel cylinder and piston assembly and connected by said valued hydraulic signal means to said return potential.

4. The anti-roll system of claim 3 wherein said tilt limiter includes a first port in a respective front wheel cylinder and piston assembly, said port being hydraulically return-connected to said valved hydraulic signal means.

5. The anti-roll system of claim 2 wherein, for each of said pistons, said ported means includes a first port with a biased port cover for conducting hydraulic fluids in a first direction through said piston and a second port with a biased port cover for conducting hydraulic fluid in a second direction through said piston, said first direction being substantially opposite to said second direction.

6. The anti-roll system of claim 4 wherein said front wheel cylinder and piston assembly includes a second port connected to said hydraulic circuit for conducting said pressurizing hydraulic potential into said front wheel cylinder and piston assembly, and a moveable piston, said moveable piston being in a first position closing said first port to said second port and moving to a second position opening said first port to said second port in response to said second port conducting said pressurizing hydraulic potential into said front wheel cylinder and piston assembly.

7. The anti-roll system of claim 3 wherein each of said front wheel cylinder and piston assemblies includes a tilt limiter.

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

9. The anti-roll system of claim 4, further including a damping means in said hydraulic circuit for damping hydraulic surges.

10. A shock-absorbing hydraulic cylinder and piston assembly comprising:

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

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

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 port through said piston between said first and second ends, 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.

11. A hydraulic cylinder and piston assembly, comprising:

a cylinder with spaced-apart first and second hydraulic ports, each of said ports opening into the interior of said cylinder;

a position sensing port opening into the interior of said cylinder, said position sensing port located between said first and second ports;

a piston rod in said cylinder;

a piston means attached to said piston rod and slidably contained within said cylinder for reciprocal, hydraulically-actuated movement between said lower and said position sensing ports;

a floating piston in said cylinder coaxial with said piston rod for reciprocal movement within said cylinder between said fixed piston and said position sensing port; and

means for positioning said floating piston with respect to said position-sensing port such that said floating piston is moved to uncover said position sensing port in response to hydraulic pressurization of the interior of said cylinder through said first port and is moved by said means to cover said position-sensing port when said pressurizing hydraulic potential is removed from said first port.

12. The hydraulic cylinder and piston assembly of claim 11, wherein said floating piston includes a hollow cylinder with an open end and a closed end, said closed end including a central bore for receiving said piston rod.

13. The hydraulic cylinder and piston assembly of claim 12, wherein said open end of said floating piston contacts said piston means.

14. The hydraulic cylinder and piston assembly of claim 11, further including a shock-absorbing assembly, said assembly comprising:

a rigid annular retainer attached coaxially to said piston rod, said floating piston being positioned between said rigid annular retainer and said rigid piston means, said annular retainer having a radius less than the radius of said cylinder; and

a flexible annular washer seated coaxially on said piston rod against said rigid annular retainer, said flexible annular washer having a radius less than the radius of said cylinder but greater than the radius of said rigid annular retainer.

15. The hydraulic cylinder and piston assembly of claim 14, further including a springlike structure acting between said shock absorbing assembly and said cylinder

16. The hydraulic cylinder and piston assembly of claim 14, further including a springlike structure acting between said shock absorbing assembly and said floating piston.

17. The hydraulic cylinder and piston assembly of claim 14, further including a springlike structure acting between said floating piston and said piston means.

18. The hydraulic cylinder and piston assembly of claim 14, further including:

a first springlike structure acting between said shock absorbing assembly and said cylinder;

a second springlike structure acting between said shock absorbing assembly and said floating piston; and

a third springlike structure acting between said floating piston and said piston means.

19. 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 piston movement of the first cylinder and piston assembly; 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 piston movement of the second cylinder and piston assembly.

20. The system of claim 19 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 port in response to conducting fluid into the first cylinder and piston assembly through the upper port.

21. The system of claim 19 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 port in response to conducting fluid into the second cylinder and piston assembly through the upper port.

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

a second pair of the cylinder and piston assemblies being attached to 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 wheel;

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 movement of the piston of the cylinder and piston assembly, the piston being in a first position closing the position-sensing port and moving to a second position opening the position-sensing port in response to the differential fluid signal; 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 movement of the piston of the cylinder and piston assembly, the piston being in a first position closing the position-sensing port and moving to a second position opening the position-sensing port in response to the differential fluid signal.