Wheel speed sensor

• US 3,890,517 A
• Filed: 11/23/1973
• Issued: 06/17/1975
• Est. Priority Date: 11/23/1973
• Status: Expired due to Term

• Current Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Gregg K. Mcpherson, Jeffrey D. Marsh
• Inventors: Marsh, Jeffrey D., McPherson, Gregg K.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Hille, Rolf
• Application Number:
  US05/418,558
• Time in Patent Office: 571 Days
• Field of Search: 324/173,174 310/90,155,168-170
• US Class Current: 310/168
• CPC Class Codes: B60T 8/329 Systems characterised by their speed sensor arrangements
• CPC Class Codes: G01P 3/443 mounted in bearings bearings F16C
• CPC Class Codes: G01P 3/488 delivered by variable reluctance detectors

Abstract

A wheel speed sensor including a rotor and a stator with the stator being coaxially disposed within an elastomeric member for incremental axial movement upon engagement with the rotor. The stator includes a pole member, a bobbin and coil assembly, and a magnet which are axially aligned to provide an elongated stator structure which is coaxially disposed in a tubular member which guides the incremental axial movement of the stator. A method for prestressing the elastomeric member for setting the required applied force for axially moving the stator.

Claims

1. A speed sensor for providing an electrical signal representative of the relative rotation between a pair of members comprising:

a stator having a first surface;

a rotor mounted on a rotatable one of said members having a second surface for confrontation with said first surface to provide a magnetic path between said first and second surfaces having a reluctance which varies with relative rotation of said stator and rotor;

magnetic means associated with said magnetic path for providing a source of magnetic flux for said path;

coil means associated with said magnetic path for providing said electrical signal; and

mounting means for mounting said stator on the other of said members with said first and second surfaces in confrontation, said mounting means including resilient means providing relative movement of said stator along a predetermined path with respect to said rotor upon engagement of said first and second surfaces tending to move said first and second surfaces apart and for restraining said relative movement when said first and second surfaces do not engage, said resilient means being an elastomeric member at least partly surrounding said stator and extending therealong for supporting engagement with said stator at at least two spaced locations along said path of movement.

2. A speed sensor according to claim 1 wherein said elastomeric member engages said stator for allowing said relative movement upon engagement of said first and second surfaces and for resisting said relative movement when said first and second surfaces do not engage.

3. A speed sensor according to claim 1 wherein said elastomeric member is an elongated member having a bore and said stator resides in said bore.

4. A speed sensor for providing an electrical signal representative of the relative rotation between a pair of members comprising:

a stator having a first surface and a second surface which has serrations;

a rotor mounted on a rotatable one of said members having a second surface for confrontation with said first surface to provide a magnetic path between said first and second surfaces having a reluctance which varies with relative rotation of said stator and rotor;

magnetic means associated with said magnetic path for providing a source of magnetic flux for said path;

coil means associated with said magnetic path for providing said electrical signal; and

mounting means for mounting said stator on the other of said rotatable members with said first and second surfaces in confrontation, said mounting means including resilient means providing relative movement of said stator along a predetermined path with respect to said rotor upon engagement of said first and second surfaces tending to move said first and second surfaces apart and for restraining said relative movement when said first and second surfaces do not engage, said resilient means engaging said serrations for supporting said stator at at least two spaced locations along said path.

5. A speed sensor according to claim 4 wherein said resilient means is an elastomeric member which engages said serrations.

6. A speed sensor according to claim 1 wherein said stator is disposed along an axis and said predetermined path is said axis.

7. A speed sensor according to claim 6 wherein said stator includes said magnetic means and said coil means and wherein said magnetic means and said coil means are coaxially disposed along said axis.

8. A speed sensor according claim 1 wherein said one member is rotatable with a wheel of a vehicle, said other member is connected to a non-rotatable support member for said wheel and said one member provides movement of said first surface relative to said second surface upon rotation of said wheel tending to cause said first and second surfaces to engage.

9. A speed sensor according to claim 1 wherein said stator is movable along said path upon engagement of said first and second surfaces with a predetermined engaging force therebetween in the direction of said path and wherein said elastomeric member is prestressed to establish predetermined engaging force.

10. A speed sensor according to claim 10 further including prestressing means cooperating with said elastomeric member for prestressing said elastomeric member to establish said predetermined engaging force.

11. A speed sensor according to claim 10 wherein said elastomeric member has a pair of opposite end portions and said prestressing means engages said opposite end portions to prestress said elastomeric member to establish said predetermined engaging force and to support said stator at said spaced locations.

12. A speed sensor for providing an electrical signal representative of the relative rotation between a pair of members comprising:

A stator having a first surface;

a rotor mounted on a rotatable one of said members having a second surface for confrontation with said first surface to provide a magnetic path between said first and second surfaces having a reluctance which varies with relative rotation of said stator and rotor;

magnetic means associated with said magnetic path for providing a source of magnetic flux for said path;

coil means associated with said magnetic path for providing said electrical signal; and

mounting means for mounting said stator on the other of said members with said first and second surfaces in confrontation, said mounting means including a resilient member providing relative movement of said stator along a predetermined path with respect to said rotor upon engagement of said first and second surfaces with a predetermined engaging force therebetween in the direction of said path of movement tending to move said first and second surfaces apart and for restraining said relative movement when said first and second surfaces do not engage and a prestressing member having a chamfer which engages said resilient member for prestressing said resilient member to establish said predetermined engaging forcE, said resilient member supporting said stator at at least two spaced locations along said path of movement.

13. A speed sensor according to claim 12 wherein said resilient member has a chamfer which is engaged by said chamfer of said prestressing member.

14. A speed sensor according to claim 13 wherein said chamfer of said prestressing member and said chamfer of said resilient member are at differing angles with respect to said predetermined path whereby an interference is established therebetween upon engagement of said chamfers.

15. A speed sensor according to claim 10 wherein said prestressing means includes a first prestressing member and a second prestressing member in interfitting relationship, said resilient member being disposed intermediate at least a portion of each of said first and second prestressing members.

16. A speed sensor according to claim 15 where at least one of said prestressing members is a tubular member and said resilient member is a tubular member in cooperative relationship herewith.

17. A speed sensor according to claim 16 where said at least one of said first prestressing members and said resilient member are cylindrical.

18. A speed sensor for providing an electrical signal representative of the relative rotation between a pair of members comprising:

a stator having a first surface;

a rotor mounted on a rotatable one of said members having a second surface for confrontation with said first surface to provide a magnetic path between said first and second surfaces having a reluctance which varies with relative rotation of said stator and rotor;

magnetic means associated with said magnetic path for providing a source of magnetic flux for said path;

coil means associated with said magnetic path for providing said electrical signal; and

mounting means for mounting said stator on the other of said members with said first and second surfaces in confrontation, said mounting means including a resilient member providing relative movement of said stator along a predetermined path with respect to said rotor upon engagement of said first and second surfaces with a predetermined engaging force tending to move said first and second surfaces apart and for restraining said relative movement when said first and second surfaces do not engage, said resilient member supporting said stator at at least two spaced locations along said path having a cantilever portion which establishes said predetermined engaging force.

19. A speed sensor according to claim 18 wherein said resilient member has two cantilever portions which are spaced along said predetermined path to support said stator at said spaced locations.

20. A speed sensor according to claim 18 wherein said resilient member is a tubular member and said cantilever portion is a radially-extending flange.

21. A speed sensor according to claim 20 having two spaced radially-extending flanges providing two spaced cantilever portions.

22. A speed sensor according to claim 18 further including a support member cooperative with said resilient member for supporting said resilient member, said cantilever portion extending outwardly from said support member whereby said cantilever portion is not supported by said support member.

23. A speed sensor according to claim 22 wherein said support member is a collar member which at least partially surrounds said resilient member.

24. A speed sensor according to claim 1 wherein said elastomeric member provides an engaging force between said mounting means and said stator at said two spaced locations along said path which supports said stator.

25. A speed sensor according to claim 1 wherein said elastomeric member provides a distributed force along said stator for supporting said stator.

26. A speed sensor for providing an electrical signal representative of the relative rotation between a pair of members comprising:

a stator having a first surface;

a rotor mounted on a rotatable one of said Members having a second surface for confrontation with said first surface to provide a magnetic path between said first and second surfaces having a reluctance which varies with relative rotation of said stator and rotor;

magnetic means associated with said magnetic path for providing a source of magnetic flux for said path;

coil means associated with said magnetic path for providing said electrical signal; and

mounting means for mounting said stator on the other of said members with said first and second surfaces in confrontation, said mounting means including resilient means providing relative movement of said stator along a predetermined path with respect to said rotor upon engagement of said first and second surfaces tending to move said first and second surfaces apart with a predetermined engaging force therebetween in the direction of said path of movement and for restraining said relative movement when said first and second surfaces do not engage and prestressing means cooperating with said resilient means for prestressing said resilient means to establish said predetermined engaging force.

27. A speed sensor according to claim 26 wherein said movement occurs upon a predetermined engaging force between said first and second surfaces and said resilient member has a pair of opposite end portions and said prestressing means engages said opposite end portions to prestress said resilient member to establish said predetermined engaging force.

28. A speed sensor according to claim 26 wherein said prestressing means includes a prestressing member having a chamfer which engages said resilient means.

29. A speed sensor according to claim 28 wherein said resilient means is a resilient member which has a chamfer which is engaged by said chamfer of said prestressing member.

30. A speed sensor according to claim 29 wherein said chamfer of said prestressing member and said chamfer of said resilient member are at differing angles with respect to said predetermined path whereby an interference is established therebetween upon engagement of said chamfers.

31. A speed sensor according to claim 26 wherein said prestressing means includes a first prestressing member and a second prestressing member in interfitting relationship, said resilient means being disposed intermediate at least a portion of each of said first and second prestressing members.

32. A speed sensor according to claim 31 where at least one of said prestressing members is a tubular member and said resilient means is a tubular member in a cooperative relationship herewith.

33. A speed sensor according to claim 32 wherein said at least one of said first and second prestressing members and said resilient members are cylindrical.