Magnetic sensor with means for retaining a magnet at a precise calibrated position

• US 5,488,294 A
• Filed: 01/18/1995
• Issued: 01/30/1996
• Est. Priority Date: 01/18/1995
• Status: Expired due to Term

• Current Assignee: Sensata Technologies Incorporated (Sensata Technologies Holding Plc)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Wohlers, Gary L., Liddell, Peter A., Mueller, Douglas L.
• Primary Examiner(s): O'Shea, Sandra L.
• Assistant Examiner(s): Patidar, Jay M.
• Application Number:
  US08/374,020
• Time in Patent Office: 377 Days
• Field of Search: 324/207.2, 324/207.21, 324/252, 324/202, 324/260, 324/251, 338/32 R, 338/32 H
• US Class Current: 324/207.21
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01D 5/147 influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other
• CPC Class Codes: H03K 17/9517 using galvanomagnetic devices

Abstract

A magnetic sensor is provided with a carrier that has a cavity shaped to receive a magnet in sliding association therein. Ribs are provided to guide the movement of the magnet into the cavity and a deformable rib is used to hold the magnet at a precise position determined by an active calibration process. A magnetically sensitive component is rigidly attached to a substrate and the substrate is rigidly attached to the carrier in which the cavity is formed. Electrically conductive leads are molded into the carrier and extend through the carrier to positions where they can be electrically connected to circuit runs on the substrate. A flexible wall can also be formed in the carrier to deflect in response to the insertion of a magnet into the cavity. This provides additional holding capability that retains the magnet in position when an external force is removed.

Claims

1. A magnetic sensor with adjustable magnet position for use during calibration of the magnetic sensor, comprising:

a carrier having a cavity formed therein;

a plurality of electrical leads molded into said carrier;

a magnet, said cavity being shaped to receive said magnet therein, said magnet being shaped to slide into said cavity in response to an external force;

means associated with said cavity for guiding said magnet along a preselected axis as said magnet slides into said cavity in response to said external force;

means associated with said cavity for resisting the movement of said magnet as said magnet slides into said cavity in response to said external force, said resisting means being deformable in response to forcible contact with said magnet as said magnet slides into said cavity in response to said external force, said resisting means being shaped to retain said magnet in position within said cavity when said external force is not exerted against said magnet;

a magnetically sensitive component; and

a substrate, said magnetically sensitive component being attached to said substrate, said substrate being attached to said carrier.

2. The sensor of claim 1, wherein:

said carrier is made of molded plastic.

3. The sensor of claim 1, wherein:

said magnet is a permanent magnet.

4. The sensor of claim 1, wherein:

said guiding means comprises a plurality of protrusions formed in walls of said cavity.

5. The sensor of claim 4, wherein:

said plurality of protrusions comprises a plurality of ribs, said plurality of ribs being aligned in parallel association with said preselected axis.

6. The sensor of claim 1, wherein:

said resisting means comprises a deformable rib.

7. The sensor of claim 1, wherein:

said magnetically sensitive component comprises a plurality of magnetoresistive elements.

8. The sensor of claim 7, wherein:

said plurality of magnetoresistive elements are connected together in an electrical bridge arrangement.

9. The sensor of claim 1, further comprising:

a plurality of electrical components attached to said substrate and connected in electrical communication with said magnetically sensitive component.

10. The sensor of claim 1, wherein:

said plurality of electrical leads extend through said carrier and are connected in electrical communication with said magnetically sensitive component.

11. The sensor of claim 1, wherein:

said carrier, said substrate, said magnet, and said magnetically sensitive component are encapsulated within an overmolded structure.

12. A magnetic sensor with adjustable magnet position for use during calibration of the magnetic sensor, comprising:

a carrier having a cavity formed therein, said carrier being made of molded plastic;

a plurality of electrical leads molded into said carrier;

a magnet, said cavity being shaped to receive said magnet therein, said magnet being shaped to slide into said cavity in response to an external force;

means associated with said cavity for guiding said magnet along a preselected axis as said magnet slides into said cavity in response to said external force;

means associated with said cavity for resisting the movement of said magnet as said magnet slides into said cavity in response to said external force, said resisting means being deformable in response to forcible contact with said magnet as said magnet slides into said cavity in response to said external force, said resisting means being shaped to retain said magnet in position within said cavity when said external force is not exerted against said magnet;

a magnetically sensitive component; and

a substrate, said magnetically sensitive component being attached to said substrate, said substrate being attached to said carrier.

13. The sensor of claim 12, wherein:

said magnet is a permanent magnet.

14. The sensor of claim 12, wherein:

said guiding means comprises a plurality of protrusions formed in walls of said cavity.

15. The sensor of claim 14, wherein:

said plurality of protrusions comprises a plurality of ribs, said plurality of ribs being aligned in parallel association with said preselected axis.

16. The sensor of claim 12, wherein:

said resisting means comprises a deformable rib.

17. The sensor of claim 12, wherein:

said magnetically sensitive component comprises a plurality of magnetoresistive elements.

18. The sensor of claim 17, wherein:

said plurality of magnetoresistive elements are connected together in an electrical bridge arrangement.

19. The sensor of claim 12, further comprising:

a plurality of electrical components attached to said substrate and connected in electrical communication with said magnetically sensitive component, said plurality of electrical leads extend through said carrier and being connected in electrical communication with said magnetically sensitive component, said carrier, said substrate, said magnet, and said magnetically sensitive component being encapsulated within an overmolded structure.

20. A magnetic sensor with adjustable magnet position for use during calibration of the magnetic sensor, comprising:

a carrier having a cavity formed therein, said carrier being made of molded plastic;

a plurality of electrical leads molded into said carrier;

a magnet, said cavity being shaped to receive said magnet therein, said magnet being shaped to slide into said cavity in response to an external force;

means associated with said cavity for guiding said magnet along a preselected axis as said magnet slides into said cavity in response to said external force;

means associated with said cavity for resisting the movement of said magnet as said magnet slides into said cavity in response to said external force, said resisting means being deformable in response to forcible contact with said magnet as said magnet slides into said cavity in response to said external force, said resisting means being shaped to retain said magnet in position within said cavity when said external force is not exerted against said magnet;

a magnetically sensitive component;

a substrate, said magnetically sensitive component being attached to said substrate, said substrate being attached to said carrier, said magnet being a permanent magnet, said guiding means comprising a plurality of protrusions formed in walls of said cavity, said plurality of protrusions comprising a plurality of ribs, said plurality of ribs being aligned in parallel association with said preselected axis, said resisting means comprising a deformable rib, said magnetically sensitive component comprising a plurality of magnetoresistive elements, said plurality of magnetoresistive elements being connected together in an electrical bridge arrangement; and

a plurality of electrical components attached to said substrate and connected in electrical communication with said magnetically sensitive component, said plurality of electrical leads extend through said carrier and being connected in electrical communication with said magnetically sensitive component, said carrier, said substrate, said magnet, and said magnetically sensitive component being encapsulated within an overmolded structure.