Non-contact magnetically variable differential transformer

• US 6,803,758 B1
• Filed: 04/25/2003
• Issued: 10/12/2004
• Est. Priority Date: 04/25/2003
• Status: Expired due to Fees

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Nicholson, Warren Baxter
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US10/423,151
• Publication Number:
  US 20040212474A1
• Time in Patent Office: 536 Days
• Field of Search: 324/207.16, 324/207.18, 336/110, 336/115, 336/117, 336/126
• US Class Current: 324/207.18
• CPC Class Codes: G01D 5/2291 Linear or rotary variable differential transformers (LVDTs/RVDTs) having a single primary coil and two secondary coils
• CPC Class Codes: H01F 21/00 Variable inductances or transformers of the signal type H01F36/00 takes precedence

Abstract

A magnetically variable differential transformer, comprising: a primary winding; a first secondary winding; a second secondary winding; a non-movable permeable core disposed within the primary winding, the first secondary winding and the second secondary winding; and a movable magnet configured for movement about the primary winding, the first secondary winding and the second secondary winding, wherein movement of the movable magnet causes magnetic saturation of portions of the non-movable permeable core.

Claims

1. A magnetically variable differential transformer, comprising:

a primary winding;

a first secondary winding;

a second secondary winding;

a non-movable permeable core disposed within said primary winding, said first secondary winding and said second secondary winding; and

a movable magnet configured for movement about said primary winding, said first secondary winding and said second secondary winding, wherein movement of said movable magnet causes magnetic saturation of portions of said non-movable permeable core.

2. The magnetically variable differential transformer as in claim 1, wherein said movable magnet is a pair of magnets encased in a ring of plastic having an inner opening configured to allow said primary winding, said first secondary winding and said second secondary winding to pass therethrough in a non-contacting manner.

3. The magnetically variable differential transformer as in claim 1, wherein said first secondary winding and said second secondary winding are connected to each other and have induced voltages which cancel each other out when said movable magnet is in a center position with respect to said non-movable permeable core and said primary winding is connected to a source of excitation.

4. The magnetically variable differential transformer as in claim 1, wherein said primary winding, said first secondary winding, said second secondary winding and said non-movable permeable core are sealed within a non-magnetic housing and said movable magnet is configured to move about said non-magnetic housing in a non-contacting manner.

5. The magnetically variable differential transformer as in claim 1, wherein said movable magnet is secured to a connecting member adapted to translate movement to said movable magnet.

6. The magnetically variable differential transformer as in claim 5, wherein said connecting member depends away from said movable magnet in a direction that is not parallel to the direction of movement of said movable magnet.

7. The magnetically variable differential transformer as in claim 5, wherein said connecting member depends away from said movable magnet in a direction that is orthogonal to the direction of movement of said movable magnet.

8. The magnetically variable differential transformer as in claim 1, wherein said non-movable permeable core is a ferrite material.

9. A magnetically variable differential transformer, comprising:

a primary winding disposed on a center portion of a bobbin having a central opening, said bobbin being formed out of a non-magnetic material;

a first secondary winding disposed on one side of said bobbin adjacent to said primary winding;

a second secondary winding disposed on another side of said bobbin adjacent to said primary winding;

a non-movable permeable core being disposed in said central opening and being disposed within said first secondary winding, said primary winding and said second secondary winding; and

a movable magnet disposed about said primary winding, said first secondary winding and said second secondary winding, wherein movement of said movable magnet causes magnetic saturation of portions of said non-movable permeable core.

10. The magnetically variable differential transformer as in claim 9, wherein said non-movable permeable core is a ferrite material.

11. The magnetically variable differential transformer as in claim 9, wherein said first secondary winding and said second secondary winding are connected to each other and have induced voltages which cancel each other out when said movable magnet is in a center position with respect to said non-movable permeable core and said primary winding is connected to a source of excitation.

12. The magnetically variable differential transformer as in claim 11, wherein said primary winding, said first secondary winding, said second secondary winding and said non-movable permeable core are sealed within a non-magnetic housing and said movable magnet is configured to move about said non-magnetic housing in a non-contacting manner.

13. The magnetically variable differential transformer as in claim 12, wherein said movable magnet is secured to a connecting member adapted to translate movement to said movable magnet.

14. The magnetically variable differential transformer as in claim 12, wherein said movable magnet is a pair of magnets encased in a ring of having an inner opening configured to allow said primary winding, said first secondary winding and said second secondary winding to pass therethrough in a non-contacting manner.

15. A magnetically variable differential transformer, comprising:

a primary winding disposed about a center portion of a non-movable permeable core;

a first secondary winding disposed on one side of said primary winding and being disposed about a first portion of said non-movable permeable core;

a second secondary winding disposed on another side of said primary winding and being disposed about a second portion of said non-movable permeable core; and

a movable magnet being configured to magnetically saturate one of said first portion, said second portion or said center portion of said non-movable permeable core as said movable magnet moves with respect to said non-movable permeable core.

16. The magnetically variable differential transformer as in claim 15, wherein said movable magnet is a pair of magnets encased in a ring of plastic having an inner opening configured to allow said primary winding, said first secondary winding and said second secondary winding to pass therethrough in a non-contacting manner.

17. The magnetically variable differential transformer as in claim 15, wherein said first secondary winding and said second secondary winding are connected to each other and have induced voltages which cancel each other out when said center section of said non-movable permeable core is saturated by said movable magnet and said primary winding is connected to a source of excitation.

18. The magnetically variable differential transformer as in claim 15, wherein said primary winding, said first secondary winding, said second secondary winding and said non-movable permeable core are sealed within a non-magnetic housing and said movable magnet is configured to move about said non-magnetic housing in a non-contacting manner.

19. The magnetically variable differential transformer as in claim 18, wherein said movable magnet is secured to a connecting member adapted to translate movement to said movable magnet.

20. The magnetically variable differential transformer as in claim 19, wherein said connecting member depends away from said movable magnet in a direction that is not parallel to the direction of movement of said movable magnet.

21. The magnetically variable differential transformer as in claim 20, wherein said connecting member depends away from said movable magnet in a direction that is orthogonal to the direction of movement of said movable magnet.

22. A method for tracking the movement of a movable object with a variable differential transformer, comprising:

providing an excitation to a primary winding disposed between a first secondary winding and a second secondary winding, said primary winding, said first secondary winding and said second secondary winding are each disposed about a non-moveable permeable core, wherein said first secondary winding and said second secondary winding are connected to each other and provide an output corresponding to voltages induced within said first secondary winding and said second secondary winding by said primary winding; and

coupling a movable magnet to the movable object wherein said movable magnet saturates portions of said non-moveable permeable core thereby modifying the output corresponding to voltages induced within said first secondary winding and said second secondary winding by said primary winding.

23. The method as in claim 22, wherein said movable magnet is coupled to the movable object by a connecting member that depends away from said movable magnet in a direction that is not parallel to the direction of movement of said movable magnet.

24. The method as in claim 23, wherein said connecting member depends away from said movable magnet in a direction that is orthogonal to the direction of movement of said movable magnet.

25. The method as in claim 22, wherein said primary winding, said first secondary winding, said second secondary winding and said non-moveable permeable core are sealed within a non-magnetic housing and said movable magnet is configured to about said non-magnetic housing in a non-contacting manner.