Wheel rotation sensor and accelerometer to determine out of balance condition

• US 6,353,384 B1
• Filed: 08/09/1999
• Issued: 03/05/2002
• Est. Priority Date: 08/09/1999
• Status: Expired due to Fees

• Current Assignee: Meritor Heavy Vehicle Systems, LLC (Meritor, Inc. (Nevada))
• Original Assignee: Meritor Heavy Vehicle Systems, LLC (Meritor, Inc. (Nevada))
• Inventors: Kramer, Dennis A.
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Previl, Daniel
• Application Number:
  US09/371,142
• Time in Patent Office: 939 Days
• Field of Search: 340/438, 340/440, 340/442, 340/467, 340/669, 701/69, 701/70, 701/71, 73/66
• US Class Current: 340/438
• CPC Class Codes: G01M 1/28 with special adaptations for determining imbalance of the body in situ, e.g. of vehicle wheels
• CPC Class Codes: G01P 15/00 Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration

Abstract

A system for determining an out of balance wheel condition on a vehicle incorporates a wheel speed signal such as provided by ABS systems. The wheel speed signal is associated with acceleration information from an accelerometer on the axle. If a particular acceleration profile is repeated across several rotational cycles of the wheels, then an indication is made that an out of balance condition exists.

Claims

1. A method of determining a wheel condition for a moving vehicle comprising the steps of:

(1) associating an accelerometer with a pair of wheels on a vehicle;

(2) providing a timing signal of the rotation of at least one wheel on a vehicle;

(3) associating accelerometer information with said timing information on wheel rotation while the vehicle is being driven;

(4) determining whether acceleration profiles repeat on repeated revolutions of said wheels; and

(5) indicating an out of balance condition when a positive determination is made at step (4).

2. A method as set forth in claim 1, wherein said timing information is ABS rotation information on the vehicle.

3. A method as set forth in claim 2, wherein said ABS information includes a series of pulses indicating particular positions in the rotational cycle of the tire.

4. A method as set forth in claim 1, wherein said acceleration information is provided by an accelerometer mounted on an axle between two of said wheels.

5. A method as set forth in claim 1, wherein a minimum acceleration level is required for an indication of an out of balance condition.

6. A method as set forth in claim 1, wherein an out of balance display is provided.

7. A method as set forth in claim 1, wherein when a determination is made that a particular acceleration profile is not repeating, no determination of an out of balance condition is made.

8. A system for determining an out of balance wheel comprising:

an axle mounting a pair of opposed wheels;

a pair of wheels mounted on said axle;

wheel speed rotation sensors associated with at least one of said wheels and communicating with a control;

an accelerometer mounted adjacent said axle to provide acceleration information on said axle to said control; and

said control operable to associate said wheel speed information with said accelerometer information while the wheels are being driven to determine whether a particular acceleration profile is repeating on each revolution of said wheels, and a repeating acceleration profile being identified as an out of balance condition.

9. A system as recited in claim 8, wherein a signal is provided should an indication be made that an acceleration profile is repeating on plural rotations of the wheel.

10. A system as recited in claim 8, wherein said wheel speed information is ABS rotation pulses.

11. A system as recited in claim 8, wherein said accelerometer determines accelerations along the axis of said axle.

12. A system as recited in claim 8, wherein said acceleration profiles must exceed a predetermined limit before an indication is made that an out of balance condition exists.

13. A system as recited in claim 8, wherein said control being operable to recognize that a non-repeating acceleration profile is not indicative of an out of balance condition.