Position sensor with integrated signal-conditioning electronics on a printed wiring board

• US 6,313,624 B1
• Filed: 11/27/1998
• Issued: 11/06/2001
• Est. Priority Date: 11/27/1998
• Status: Expired due to Fees

• Current Assignee: National Aeronautics and Space Administration (Government of the United States of America)
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Smith, Dennis A., Howard, David E., Alhorn, Dean C.
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US09/208,401
• Time in Patent Office: 1,075 Days
• Field of Search: 324/173, 324/174, 324/207.12, 324/207-5-2, 324/207.25, 735/143.9, 336/122, 336/123, 336/84.R, 336/84.C, 336/84.M, 336/87, 341/15, 318/660, 318/661, 318/799, 310/68.B, 310/168, 340/870.31, 340/870.32
• US Class Current: 324/207.17
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01D 5/2086 by movement of two or more coils with respect to two or more other coils

Abstract

A position sensor, such as a rotary position sensor, includes the signal-conditioning electronics in the housing. The signal-conditioning electronics are disposed on a printed wiring board, which is assembled with another printed wiring board including the sensor windings to provide a sub-assembly. A mu-metal shield is interposed between the printed wiring boards to prevent magnetic interference. The sub-assembly is disposed in the sensor housing adjacent to an inductor board which turns on a shaft. The inductor board emanates an internally or externally generated excitation signal that induces a signal in the sensor windings. The induced signal represents the rotary position of the inductor board relative to the sensor winding board.

Claims

1. A position sensor, comprising:

(a) a housing;

(b) a movable shaft, disposed at least partially in the housing, for being moved in accordance with the position to be sensed;

(c) a first sensor component, mounted on the shaft so as to rotate with the shaft, for emanating an internally or externally generated excitation signal; and

(d) a second sensor component mounted in the housing so as not to rotate relative to the housing, the second sensor component comprising;

(i) a first printed wiring board for producing a raw signal induced by the excitation signal in response to a rotary displacement between the first sensor component and the second sensor component;

(ii) a second printed wiring board for converting the raw signal into a position-indicating signal; and

(iii) a magnetic shield disposed between the first printed wiring board and the second printed wiring board;

the movable shaft being secured to the first sensor component so that movement of the movable shaft causes the rotary displacement.

2. A position sensor as in claim 1, wherein:

the first printed wiring board has a sensor coil formed thereon for producing the raw signal;

the second printed wiring board has signal-conditioning electronics mounted thereon for signal-conditioning the raw signal.

3. A position sensor as in claim 2, wherein the first sensor component comprises an inductor board for emanating the excitation signal.