Air spring system having an integral height sensor

• US 5,707,045 A
• Filed: 09/05/1996
• Issued: 01/13/1998
• Est. Priority Date: 09/05/1996
• Status: Expired due to Fees

• Current Assignee: Firestone Industrial Products
• Original Assignee: Bridgestone Firestone North American Tire LLC (Bridgestone Corporation)
• Inventors: Easter, Mark R.
• Primary Examiner(s): Ballato, Josie
• Application Number:
  US08/708,442
• Time in Patent Office: 495 Days
• Field of Search: 188/1.11 R, 188/1.11 E, 267/64.16, 267/64.28, 267/64.17, 267/64.19, 267/4.21, 267/64.23, 267/64.24, 267/64.22, 267/64.18, 280/707, 280/DIG. 1
• US Class Current: 267/64.21
• CPC Class Codes: B60G 17/01933 Velocity, e.g. relative velocity-displacement sensors
• CPC Class Codes: B60G 2202/152 Pneumatic spring
• CPC Class Codes: B60G 2204/111 on pneumatic springs
• CPC Class Codes: B60G 2204/126 Mounting of pneumatic springs
• CPC Class Codes: B60G 2206/424 Plunger or top retainer construction for bellows or rolling lobe type air springs
• CPC Class Codes: B60G 2206/7101 Fiber-reinforced plastics [FRP]
• CPC Class Codes: B60G 2206/7104 Thermoplastics
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/60 Load
• CPC Class Codes: B60G 2401/14 Photo or light sensitive means, e.g. Infrared
• CPC Class Codes: B60G 2401/172 Hall effect
• CPC Class Codes: B60G 2401/26 Resistance type, e.g. as level indicator
• CPC Class Codes: F16F 2230/08 Sensor arrangement
• CPC Class Codes: F16F 9/05 the flexible wall being of the rolling diaphragm type

Abstract

An air spring system adapted to be mounted on a vehicle for absorbing road shocks exerted on the vehicle and for maintaining the vehicle body level with respect to the axles. The air spring includes an end plate and a piston sealingly connected to the open ends of a flexible elastomeric sleeve to form a pressurized fluid chamber therebetween. The flexible elastomeric sleeve rolls over the piston to allow for expansion and contraction of the chamber during shocks. A height sensor is positioned between the sleeve and the piston and in some embodiments includes elements that are molded or embedded within the sleeve and/or piston or both.

Claims

1. An air spring leveling system comprising:

a pair of end members located in a generally axial spaced relationship when in an at-rest position, said end members being adapted to be mounted on spaced apart portions of a vehicle and movable towards and away from each other upon said vehicle to absorb road shocks as said vehicle encounters road shocks and to maintain said spaced apart vehicle portions at a predetermined spaced relationship when in said at-rest positions;

a fluid pressure chamber formed between said end members by a flexible elastomeric sleeve having opposed open ends sealingly connected to said end members respectively, said flexible elastomeric sleeve being foldable partially over one of said end members thereby defining a covered region of said folded over end member and a corresponding covering region on the flexible elastomeric sleeve;

a sensor for sensing relative distance between said end members and selectively producing a height sensed signal responsive thereto, said sensor being positioned within at least one of said covered region and said covering region when the system is in said at-rest position; and

a pressurized fluid source fluidly connected to the fluid pressure chamber and electrically connected to a computer, the pressurized fluid source controlled by the height sensed signal from said sensor and the computer for regulating the amount of fluid within said fluid pressure chamber by controlling fluid entry and exit to maintain a predetermined axial separation between said end members when in said at-rest position.

2. The air spring leveling system of claim 1 wherein the sensor further comprises a transmitter and a target.

3. The air spring leveling system of claim 2 wherein the target functions as a sensor activator.

4. The air spring leveling system of claim 3 wherein the sensor further comprises electronic circuit means operatively connecting the transmitter to one of a computer and an electric power source, and the target to the other of the computer and the electric power source.

5. The air spring leveling system of claim 3 wherein at least one of the transmitter and the target is at least partially embedded in one of the covered region and the covering region, and the other is attached to the other of the covered region and the covering region.

6. The air spring leveling system of claim 5 wherein an electronic circuit means electrically connect the sensor to the computer, the electronic circuit means being at least partially embedded within the one of the covered region and the covering region that the sensor is embedded in.

7. The air spring leveling system of claim 5 wherein the transmitter comprises a microchip.

8. The air spring of claim 7 wherein the microchip is embedded in one of the end members, and the sensor activator is a metal strip.

9. The air spring leveling system of claim 5 wherein the transmitter comprises an optical sensor.

10. The air spring leveling system of claim 9 wherein the optical sensor is embedded within one of the end members, and the sensor activator is a reflector.

11. The air spring leveling system of claim 5 wherein the transmitter comprises a magnetic sensor.

12. The air spring leveling system of claim 11 wherein the magnetic sensor is embedded within one of the end members, and the sensor activator is an elongated metal strip.

13. The air spring leveling system of claim 5 wherein the sensor activator is a metal strip.

14. The air spring leveling system of claim 5 wherein the sensor activator is a conductive strip of polymer containing electrically conductive carbon black.

15. The air spring leveling system of claim 5 wherein the sensor activator is a reflector.

16. The air spring leveling system of claim 5 wherein the sensor activator is an insulated conductive means with an access window thereto thereby allowing magnetic waves to pass to the conductive means only through the window.

17. The air spring leveling system of claim 1 wherein the end members comprise an end plate and a piston member.

18. The air spring leveling system of claim 17 wherein the folded over end member is the piston member.

19. An air spring leveling system comprising:

a rigid piston being adapted to be mounted on a first portion of a vehicle frame;

a rigid end member adapted to be mounted on a second portion of the vehicle frame, said end member spaced apart from said piston;

a flexible elastomeric sleeve having opposed ends sealingly connected to said piston and end member, respectively, thereby defining a fluid pressure chamber within the sleeve between said piston and end member;

a pressurized fluid source connected to the fluid pressure chamber for regulating the amount of fluid within said chamber; and

,

a sleeve displacement sensor embedded within said piston outside of the fluid pressure chamber for sensing relative distance between said piston and end member, said sensor adapted to signal said pressurized fluid source to regulate fluid entry and exit to maintain a predetermined separation between said piston and end member.

20. The air spring leveling system of claim 19 wherein the flexible elastomeric sleeve being adapted to flex as the distance between said piston and end member changes during absorption of a shock as said vehicle frame encounters road shocks whereby the flexing includes rolling of the sleeve in part over the piston defining a covered region of said piston and a covering region of said sleeve.

21. The air spring leveling system of claim 19 further comprising electronic circuit means through which the sleeve displacement sensor signals the pressurized fluid source to regulate fluid entry and exit to maintain the predetermined separation between said piston and end member.

22. The air spring leveling system of claim 21 wherein the electronic circuit means is embedded in the piston and extends from the sensor to a computer.

23. The air spring leveling system of claim 21 further comprising an elongated conductive material substantially entirely embedded within the sleeve with the exception of an exposed portion in the configuration of a button for interacting with said sensor.