BRAKE BASED VISCOUS COUPLING ALTERNATIVE VEHICLE DIFFERENTIAL

• US 20100063701A1
• Filed: 09/09/2008
• Published: 03/11/2010
• Est. Priority Date: 09/09/2008
• Status: Abandoned Application

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Caporali, Michael E., Craig, William C., Stevens, Richard S.
• Application Number:
  US12/206,992
• Publication Number:
  US 20100063701A1
• Time in Patent Office: Days
• US Class Current: 701/69
• CPC Class Codes: B60K 17/351 comprising a viscous clutch
• CPC Class Codes: F16H 2048/204 Control of arrangements for suppressing differential actions
• CPC Class Codes: F16H 48/26 using fluid action, e.g. viscous clutches
• CPC Class Codes: F16H 48/30 using externally-actuatable means
• CPC Class Codes: Y10T 74/19005 Nonplanetary gearing differential type [e.g., gearless differentials]

Abstract

A vehicle and a method for mechanical decoupling of front and rear wheels and left and right wheels of a vehicle by mechanically decoupling the left and right wheels, while controlling the braking to maintain proper wheel speed during vehicle maneuvers.

Claims

1. In a vehicle having front and rear wheels and left and right wheels, the improvement comprising a mechanical decoupling assembly for the drive axles from left to right and a brake based control assembly cooperating therewith to maintain proper wheel speed during vehicle maneuvers.

2. The improvement of claim 1 wherein the mechanical decoupling assembly includes a viscous coupling.

3. The improvement of claim 2 wherein the mechanical decoupling and the brake based control assembly change the speed of the wheel as a vehicle executes a turn whereby the inner wheels during such turn rotate at a slower speed than the outer wheels.

4. The improvement of claim 3 further comprising an arrangement for determining whether the desired wheel speed differential is acceptable and apply differential speed control if it is not acceptable.

5. The improvement of claim 4 wherein the mechanical decoupling and the brake based control assembly apply the differential speed control.

6. The improvement of claim 5 wherein the mechanical decoupling assembly includes a front viscous coupling, a rear viscous coupling and a center viscous coupling.

7. The improvement of claim 6 further comprising gear reduction hubs at each wheel.

8. The improvement of claim 1 further comprising a data information collection arrangement for providing steering wheel angle, ABS wheel speed, inertial information, brake application information, acceleration pedal angel, vehicle speed and viscous coupling temperature for determining whether the vehicle is in a skid.

9. A method for mechanical decoupling of front and rear wheels and left and right wheels of a vehicle, comprising the steps of:

a. mechanically decoupling of the left and right wheels, while

b. controlling the braking to maintain proper wheel speed during vehicle maneuvers.

10. The method of claim 9 wherein the mechanical decoupling step is carried out using a viscous coupling and controlling the brakes is carried out using a set of control algorithms.

11. The method of claim 10 wherein during a turn the speeds of the wheels are changed as the vehicle executes a turn so that the inner wheels during such turn rotate at a slower speed than the outer wheels.

12. The method of claim 11 further comprising the step of determining whether the desired wheel speed differential is acceptable and applying differential speed control if it is not acceptable.

13. The method of claim 12 wherein the differential speed control is provided by the mechanical decoupling of the left and right wheels and controlling the braking.

14. The method of claim 11 further comprising the step of determining whether the vehicle is in a skid, and if it is, stability control is applied.

15. The method of claim 14 further comprising applying traction control if the vehicle in not in a skid but is slipping.

16. The method of claim 15 further comprising, in the event the vehicle is not is a skid and is not slipping monitoring steering wheel angle, ABS wheel speed and VC temperature and calculating the desired wheel speed differential.

17. The method of claim 16 further comprising determining whether the speed differential is correct and if not applying differential speed control.