Magnetic non-contacting rotary transducer

• US 6,498,480 B1
• Filed: 11/22/2000
• Issued: 12/24/2002
• Est. Priority Date: 11/22/2000
• Status: Expired due to Fees

• Current Assignee: Wabash Technologies Incorporated (Sensata Technologies Holding Plc)
• Original Assignee: Wabash Technologies Incorporated (Sensata Technologies Holding Plc)
• Inventors: Manara, Alan H.
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US09/721,228
• Time in Patent Office: 762 Days
• Field of Search: 324/207.2, 324/207.21, 324/207.25, 324/207.26, 324/207.22, 324/235, 330/32.R, 330/32.H, 123/617
• US Class Current: 324/207.2
• CPC Class Codes: F02P 7/07 Hall-effect pick-up devices
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A magnetic rotary transducer for providing a signal indicative of a rotational position of a control shaft about a rotational axis over a defined range of rotation is disclosed. The magnetic rotary transducer comprises a pair of magnets and a rotor including a pair of loop pole pieces, and an elongated pole piece having a first end adjoined to one of the loop pole pieces and a second end adjoined to the other loop pole piece. Each loop pole piece includes an inner surface defining an air gap area. The control shaft is positioned within the air gap area of one of the loop pole pieces and adjoined thereto whereby the rotor synchronously rotates with the control shaft about the axis over the defined range of rotation. The pair of magnets are adjoined to the other loop pole piece whereby two separate and distinct magnetic fields are generated within the air gap are of the loop pole piece. The magnetic rotary transducer further comprises a magnetic flux sensitive transducer positioned within the air gap area. The magnetic flux sensitive transducer is operable to provide a signal indicative of the rotational position of the control shaft.

Claims

1. A magnetic rotary transducer for sensing the instantaneous rotational position of an object, comprising:

a loop pole piece operable to be rotated about an axis between a first rotational position and a second rotational position, said loop pole piece defining an air gap area;

a first magnet generating a first magnetic field within said air gap area, said first magnet adjoined to said loop pole piece whereby said first magnetic field is synchronously rotated with said loop pole piece about said axis;

a second magnet generating a second magnetic field within said air gap area and spaced from said first magnetic field, said second magnet adjoined to said loop pole piece whereby said second magnetic field is synchronously rotated with said loop pole piece about said axis;

a control shaft operably coupled between the loop pole piece and the object whereby said first and second magnetic fields are synchronously rotated about said axis in response to rotation of the object; and

a first magnetic flux sensitive transducer positioned within said air gap area, said first magnetic flux sensitive transducer operable to provide a first signal indicative of a third rotational position of said loop pole piece corresponding to the instantaneous rotational position of the object.

2. The magnetic rotary transducer of claim 1, wherein said first magnetic flux sensitive transducer is entirely within said first magnetic field and entirely spaced from said second magnetic field when said third rotational position coincides with said first rotational position.

3. The magnetic rotary transducer of claim 2, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and entirely within said second magnetic field when said third rotational position coincides with said second rotational position.

4. The magnetic rotary transducer of claim 2, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

5. The magnetic rotary transducer of claim 2, wherein said first magnetic flux sensitive transducer is partially within from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

6. The magnetic rotary transducer of claim 1, wherein said first magnetic flux sensitive transducer is partially within said first magnetic field and entirely spaced from said second magnetic field when said third rotational position coincides with said first rotational position.

7. The magnetic rotary transducer of claim 6, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and entirely within said second magnetic field when said third rotational position coincides with said second rotational position.

8. The magnetic rotary transducer of claim 6, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

9. The magnetic rotary transducer of claim 6, wherein said first magnetic flux sensitive transducer is partially within from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

10. The magnetic rotary transducer of claim 1, wherein said first magnetic flux sensitive transducer is partially within said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said first rotational position.

11. The magnetic rotary transducer of claim 10, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and entirely within said second magnetic when said third rotational position coincides with said second rotational position.

12. The magnetic rotary transducer of claim 10, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

13. The magnetic rotary transducer of claim 10, wherein said first magnetic flux sensitive transducer is partially within from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

14. The magnetic rotary transducer of claim 1,

wherein said first signal linearly increases as said loop pole piece is rotated in a direction away from said first rotational position and toward said second rotational position; and

wherein said second signal linearly decreases as said loop pole piece is rotated in a direction toward said first rotational position and away from said second rotational position.

15. The magnetic rotary transducer of claim 1,

wherein said first magnet includes a first pole surface facing said air gap area;

and

wherein said second magnet includes a second pole surface facing said air gap area, said first pole surface and said second pole surface having identical polar characteristics; and

wherein said loop pole piece defines a pair of opposing slots, said first and second magnets being seated within respective ones of said opposing slots.

16. The magnetic rotary transducer of claim 15, wherein said first pole surface and said second pole surface are substantially parallel.

17. The magnetic rotary transducer of claim 1, further comprising:

a second magnetic flux sensitive transducer positioned within said air gap area, said second magnetic flux sensitive transducer operable to provide a second signal indicative of said third rotational position of said loop pole piece corresponding to the instantaneous rotational position of the object.

18. The magnetic rotary transducer of claim 1, further comprising:

a first magnetic flux sensitive switch disposed outside of said air gap area, said first magnetic flux sensitive switch being operable to provide a second signal indicative of when said third rotational position coincides with said first rotational position.

19. The magnetic rotary transducer of claim 18, further comprising:

a second magnetic flux sensitive switch disposed outside of said air gap area, said second magnetic flux sensitive switch being operable to provide a third signal indicative of when said third rotational position coincides with said second rotational position.

20. A system for sensing the instantaneous rotational position of an object, comprising:

a control shaft operable to be rotated about an axis between a first rotational position and a second rotational position, said control shaft operably coupled to the object to synchronously rotate said control shaft in response to rotation of the object;

a first loop pole piece operable to be synchronously rotated with said control shaft about said axis, said first loop pole piece defining an air gap area;

a first magnet generating a first magnetic field within said air gap area, said first magnet adjoined to said first loop pole piece whereby said first magnetic field is synchronously rotated with said control shaft about said axis;

a second magnet generating a second magnetic field within said air gap area and spaced from said first magnetic field, said second magnet adjoined to said first loop pole piece whereby said second magnetic field is synchronously rotated with said control shaft about said axis; and

a first magnetic flux sensitive transducer positioned within said air gap area, said first magnetic flux sensitive transducer operable to provide a first signal indicative of a third rotational position of said control shaft between said first rotational position and said second rotational position corresponding to the instantaneous rotational position of the object.

21. The system of claim 20 wherein said first magnetic flux sensitive transducer is entirely within said first magnetic field and entirely spaced from said second magnetic field when third rotational position coincides with said first rotational position.

22. The system of claim 21, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and entirely within said second magnetic field when said third rotational position coincides with said second rotational position.

23. The system of claim 21, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

24. The system of claim 21, wherein said first magnetic flux sensitive transducer is partially within from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

25. The system of claim 20, wherein said first magnetic flux sensitive transducer is partially within said first magnetic field and entirely spaced from said second magnetic field when said third rotational position coincides with said first rotational position.

26. The system of claim 25, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and entirely within said second magnetic field when said third rotational position coincides with said second rotational position.

27. The system of claim 25, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

28. The system of claim 25, wherein said first magnetic flux sensitive transducer is partially within from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

29. The system of claim 20, wherein said first magnetic flux sensitive transducer is partially within said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said first rotational position.

30. The system of claim 29, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and entirely within said second magnetic field when said third rotational position coincides with said second rotational position.

31. The system of claim 30, wherein said first magnetic flux sensitive transducer is entirely spaced from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

32. The system of claim 30, wherein said first magnetic flux sensitive transducer is partially within from said first magnetic field and partially within said second magnetic field when said third rotational position coincides with said second rotational position.

33. The system of claim 20,

wherein said first signal linearly increases as said control shaft rotates in a direction away from said first rotational position and toward said second rotational position; and

wherein said second signal linearly decreases as said control shaft rotates in a direction toward said first rotational position and away from said second rotational position.

34. The system of claim 20,

wherein said first magnet includes a first pole surface facing said air gap area;

and

wherein said second magnet includes a second pole surface facing said air gap area, said first pole surface and said second pole surface having substantially identical polar characteristics.

35. The system of claim 34, wherein said first pole surface and said second pole surface are parallel.

36. The system of claim 20 further comprising:

a second magnetic flux sensitive transducer positioned within said air gap area, said second magnetic flux sensitive transducer operable to provide a second signal indicative of said third rotational position of said control shaft corresponding to the instantaneous rotational position of the object.

37. The system of claim 20 further comprising:

a first magnetic flux sensitive switch disposed outside of said air gap area, said first magnetic flux sensitive switch being operable to provide a second signal indicative of when said third rotational position coincides with said first rotational position.

38. The system of claim 37 further comprising:

a second magnetic flux sensitive switch disposed outside of said air gap area, said second magnetic flux sensitive switch being operable to provide a third signal indicative of when said third rotational position coincides with said second rotational position.

39. The system of claim 20 further comprising:

a second loop pole piece adjoined to said control shaft; and

an elongated pole piece having a first end adjoined to said first loop pole piece and a second end adjoined to said second loop pole piece.