Position Sensing Apparatus and Method

• US 20200132874A1
• Filed: 10/30/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Kyocera AVX Components GmbH (Kyocera Corporation)
• Original Assignee: AVX Electronics Technology Ltd. (TT Electronics PLC)
• Inventors: Witts, David, Constantinou, Peter, Smith, Paul
• Granted Patent: US 11,555,940 B2
• Time in Patent Office: Days
• CPC Class Codes: G01D 2205/50 Grounding or electrostatically shielding a position sensor or encoder
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01D 5/20 by varying inductance, e.g. by a movable armature
• CPC Class Codes: G01D 5/2053 by a movable non-ferromagnetic conductive element
• CPC Class Codes: G01D 5/2258 by a movable ferromagnetic element, e.g. core
• CPC Class Codes: G01V 3/081 the magnetic field is produced by the objects or geological structures characterised by the method of magnetic field measurement G01R33/00
• CPC Class Codes: H01F 21/10 by means of a movable shield

Abstract

Inductive position sensors for sensing relative position (e.g., relative rotary position) between members are provided. In one example implementation, the inductive position sensor includes a transmit aerial having at least one transmit winding. The inductive position sensor can include a receive aerial having one or more receive windings. The inductive position sensor can include a coupling element operable to be disposed on the second member. The inductive position sensor can include processing circuitry configured to provide one or more signals indicative of the position of the first member relative to the second member based on current induced in the one or more receive windings resulting from an oscillating signal provided to the transmit winding. The inductive position sensor includes at least one electrostatic shield. The electrostatic shield can include a plurality of conductive traces arranged so that no current loops are formed in the electrostatic shield.

Claims

1. An inductive position sensor configured to detect relative position between a first member and a second member, the inductive position sensor comprising:

a transmit aerial configured to be disposed on the first member, the transmit aerial having at least one transmit winding;

a receive aerial configured to be disposed on the first member, the receive aerial comprising one or more receive windings;

a coupling element operable to be disposed on the second member;

processing circuitry configured to provide one or more signals indicative of the position of the first member relative to the second member based on current induced in the one or more receive windings resulting from an oscillating signal provided to the transmit winding; and

at least one electrostatic shield, the electrostatic shield comprising a plurality of conductive traces arranged so that no current loops are formed in the electrostatic shield.

2. The inductive position sensor of claim 1, wherein the electrostatic shield is grounded.

3. The inductive position sensor of claim 1, wherein the transmit aerial, receive aerial, and electrostatic shield are arranged as a multilayer structure.

4. The inductive position sensor of claim 1, wherein the electrostatic shield is disposed on the same layer as at least a portion of the transmit winding or the one or more receive windings.

5. The inductive position sensor of claim 1, wherein the electrostatic shield is disposed on a different layer relative to the transmit aerial and the receive aerial.

6. The inductive position sensor of claim 1, wherein the inductive position sensor comprises a first electrostatic shield and a second electrostatic shield.

7. The inductive position sensor of claim 6, wherein one or more layers associated with the transmit aerial and the receive aerial are disposed between the first electrostatic shield and the second electrostatic shield.

8. The inductive position sensor of claim 1, wherein a point on the at least one transmit winding is coupled to ground.

9. The inductive position sensor of claim 8, wherein the point on the at least one transmit winding is coupled to ground via a capacitor.

10. The inductive position sensor of claim 1, wherein the one or more receive windings comprise a sine winding and a cosine winding.

11. The inductive position sensor of claim 1, wherein the electrostatic shield comprises:

a first conductive trace extending from a first end portion to a second end portion;

a plurality of second conductive traces extending from the first conductive trace.

12. The inductive position sensor of claim 11, wherein the first conductive trace extends from the first end portion to the second end portion in an arcuate manner.

13. The inductive position sensor of claim 11, wherein the first conductive trace extends from the first end portion to the second end portion in a linear manner.

14. The inductive position sensor of claim 11, wherein the plurality of second conductive traces have about the same length.

15. The inductive position sensor of claim 11, wherein the plurality of second conductive traces have different lengths.

16. The inductive position sensor of claim 11, wherein end portions of the second conductive traces form an arcuate shape.

17. The inductive position sensor of claim 11, wherein the electrostatic shield further comprises a plurality of third conductive traces extending from the first conductive trace, the third conductive traces extending in a different direction relative to the plurality of second conductive traces.

18. The inductive position sensor of claim 1, wherein the electrostatic shield comprise a first conductive trace that at least partially surrounds a portion of the one or more receive windings.

19. A multilayer structure for use with an inductive position sensor, the multilayer structure comprising:

a transmit aerial having at least one transmit winding;

a receive aerial having one or more receive windings; and

at least one electrostatic shield, the electrostatic shield comprising a plurality of conductive traces arranged so that no current loops are formed in the electrostatic shield.

20. The multilayer structure of claim 19, wherein the electrostatic shield is grounded.