Vehicle direction detection using tone ring

• US 20050035758A1
• Filed: 08/13/2003
• Published: 02/17/2005
• Est. Priority Date: 08/13/2003
• Status: Active Grant

• Current Assignee: Bendix Commercial Vehicle Systems LLC (Estate of Heinz Hermann Thiele)
• Original Assignee: Bendix Commercial Vehicle Systems LLC (Estate of Heinz Hermann Thiele)
• Inventors: Bennett, Mark, Taneyhill, David J., Waszkowski, Paul J.
• Granted Patent: US 7,116,096 B2
• Time in Patent Office: Days
• US Class Current: 324/207.250
• CPC Class Codes: B60T 8/171 Detecting parameters used in the regulation; Measuring values used in the regulation
• CPC Class Codes: G01D 2205/85 Determining the direction of movement of an encoder, e.g. of an incremental encoder
• CPC Class Codes: G01D 5/2457 Incremental encoders having reference marks
• CPC Class Codes: G01P 13/04 Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
• CPC Class Codes: G01P 3/481 of pulse signals

Abstract

A tone ring preferably for use in a braking system of a vehicle has a first pattern of excitation indicative of speed of rotation of the tone ring, and a second pattern of excitation including frequency variations that is indicative of direction of rotation of the tone ring. The tone ring is rotated past a sensor, preferably a 2-wire passive sensor. A series of events are sensed during rotation of the tone ring past the sensor. The timing of occurrence of the events is detected and, on the basis of the timing detection, the direction of rotation of the tone ring is determined.

Claims

1. A method comprising the steps of:

rotating a tone ring past a sensor;

sensing a series of events that occur during rotation of the tone ring past the sensor;

detecting the timing of occurrence of a series of events during rotation of the tone ring past the sensor; and

determining, on the basis of the timing detection, the direction of rotation of the tone ring.

2. A method as set forth in claim 1 wherein said sensing step is performed with a passive sensor.

3. A method as set forth in claim 1 wherein said sensing step includes sensing the periods of time between a series of adjacent events that occur during rotation of a predetermined portion of the tone ring past the sensor.

4. A method as set forth in claim 3 wherein said detecting step includes detecting the existence of a predetermined pattern of periods of time between events during rotation of the predetermined portion of the tone ring past the sensor.

5. A method as set forth in claim 4 wherein said determining step includes comparing the predetermined pattern of periods of time between events to stored patterns and, on the basis thereof, determining the direction of rotation of the tone ring.

6. A method as set forth in claim 5 wherein said determining step includes comparing the pattern of periods of time between events to stored patterns that include a first pattern indicative of a first direction of rotation of the tone ring and a second pattern indicative of a second direction of rotation of the tone ring.

7. A method for detecting direction of wheel rotation, comprising the steps of:

producing a first detectable frequency pattern in response to wheel rotation in a first direction;

producing a second detectable frequency pattern in response to wheel rotation in a second direction that is opposite said first direction; and

detecting at least one of said first and second patterns to determine direction of wheel rotation.

8. A method as set forth in claim 7 wherein said step of producing a first detectable frequency pattern comprises rotating a predetermined portion of a tone ring past a sensor.

9. A method as set forth in claim 8 wherein said step of rotating a predetermined portion of a tone ring past a sensor comprises rotating a predetermined portion including teeth having leading edges that are spaced apart in a predetermined pattern of varying distances.

10. A method as set forth in claim 9 wherein said step of producing a second detectable frequency pattern includes rotating the predetermined portion of the tone ring past the sensor in an opposite direction.

11. A method as set forth in claim 7 wherein said detecting step includes detecting with a passive sensor.

12. A method as set forth in claim 11 wherein said detecting step includes detecting with a 2-wire passive magnetic pickup sensor.

13. A method comprising the steps of:

providing a tone ring rotatable with a wheel of a vehicle;

sensing the frequency of occurrence of a series of events that occur during rotation of the tone ring;

generating a first signal in response to said step of sensing the frequency that is indicative of the speed of rotation of the tone ring; and

generating a second signal in response to said step of sensing the frequency that is indicative of the direction of rotation of the tone ring;

14. A method as set forth in claim 13 wherein said step of providing a tone ring comprises providing an ABS system tone ring having a direction indicating segment with a predetermined pattern of frequency excitation that is rapidly recognizable and that is distinct from the pattern of frequency excitation that is used for wheel speed sensing.

15. Apparatus comprising:

a tone ring rotatable in response to forward or reverse movement of a vehicle, said tone ring having a pattern of excitation including frequency variations that is indicative of direction of rotation of said tone ring; and

a sensor having an output responsive to rotation of said tone ring past said sensor, said sensor having a first output responsive to rotation of said tone ring in a first direction, said sensor having a second output responsive to rotation of said tone ring in a second direction opposite said first direction, said second output being different from said first output.

16. Apparatus as set forth in claim 15 wherein said sensor is a passive sensor.

17. Apparatus as set forth in claim 16 wherein said sensor is a 2-wire magnetic pickup sensor.

18. Apparatus as set forth in claim 15 wherein said tone ring includes a direction indicating segment comprising a plurality of teeth, the distances between said teeth varying in a predetermined pattern.

19. Apparatus as set forth in claim 15 wherein said tone ring includes a plurality of teeth spaced apart in a circumferential array on said tone ring, said tone ring having a direction indicating segment that comprises a predetermined number of teeth having leading edges that are spaced apart in a predetermined pattern with differing intervals between them.

20. Apparatus as set forth in claim 19 wherein said direction indicating segment comprises a plurality of teeth that have differing circumferential lengths.

21. Apparatus as set forth in claim 19 wherein said direction indicating segment comprises a plurality of teeth that have identical circumferential lengths that are spaced apart from each other at differing distances.

22. Apparatus as set forth in claim 19 wherein said direction indicating segment comprises a plurality of teeth that have differing circumferential lengths and that are spaced apart from each other at differing distances.

23. A tone ring for use in a braking system of a vehicle, said tone ring having a first pattern of excitation indicative of speed of rotation of said tone ring, said tone ring having a second pattern of excitation including frequency variations that is indicative of direction of rotation of said tone ring.

24. A tone ring as set forth in claim 23 wherein said second pattern of excitation is provided by a direction indicating segment of teeth that have differing circumferential lengths or that are spaced apart from each other at differing distances.

25. A tone ring as set forth in claim 23 wherein said first pattern of excitation is provided by a series of teeth having regularly spaced leading edges and said second pattern of excitation is provided by a series of teeth having irregularly spaced leading edges.

26. A tone ring as set forth in claim 23 wherein said second pattern of excitation is provided by a series of teeth having leading edges that are spaced apart in a first pattern when read in a first direction and in a second pattern different from said first pattern when read in a second direction opposite said first direction.