Rotary variable differential transformer

Patent metadata

Field	Value
Publication number	US-11715587-B2
Application number	US-201916422005-A
Country	US
Kind code	B2
Filing date	May 24, 2019
Priority date	May 24, 2019
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

A rotary variable differential transformer for measuring angular displacement and method of manufacturing the same are provided herein. The rotary variable differential transformer includes a stator configured to house a primary coil configured to receive an alternating current, a first secondary coil electromagnetically coupled to the primary coil, and a second secondary coil electromagnetically coupled to the primary coil. The rotary variable differential transformer also includes a rotor positioned concentrically within the stator. The rotor is configured to receive a shaft and rotate with the shaft while the stator remains stationary. The primary coil is positioned at a first radial position within the stator spaced between about 90 to 150 degrees from each of the first secondary coil and the second secondary coil.

First claim

The invention claimed is:

1. A rotary variable differential transformer for measuring angular displacement of a shaft, the rotary variable differential transformer comprising:
a stator housing:
a primary coil configured to receive an alternating current;
a first secondary coil electromagnetically coupled to the primary coil; and
a second secondary coil electromagnetically coupled to the primary coil; and

a rotor positioned concentrically within the stator, wherein the rotor is configured to receive a shaft and rotate with the shaft while the stator remains stationary;
wherein the primary coil is positioned at a first radial position within the stator spaced between about 90 to 150 degrees from each of the first secondary coil and the second secondary coil;
wherein the rotor is configured with a magnetically permeable arcuate section extending from 180 to 270 degrees of the entire circumference of the rotor, such that 90 to 150 degrees of the circumference of the rotor defines a base portion having a smaller radius than the magnetically permeable arcuate section; and
wherein the stator further defines an airgap between 0.001 and 0.010 inches measured between the stator and the rotor.

2. The rotary variable differential transformer of claim 1 , wherein in an instance that the shaft rotates in a first radial direction, a voltage of the first secondary coil increases; and
in an instance that the shaft rotates in a second radial direction, the voltage of the second secondary coil increases,
wherein the change in voltage of the first secondary coil and the second secondary coil is linearly proportional to the rotation of the shaft.

3. The rotary variable differential transformer of claim 2 , wherein the change in voltage of the first secondary coil is linearly proportional to the rotation of the shaft within a range of rotation of the shaft and the change in voltage of the second secondary coil is also linearly proportional to the rotation of the shaft within the same range of rotation of the shaft.

4. The rotary variable differential transformer of claim 3 , wherein the range of rotation of the shaft is from 55 degrees in the first radial direction to 55 degrees in the second radial direction.

5. The rotary variable differential transformer of claim 1 , wherein the stator is housed within an environmentally sealed housing.

6. The rotary variable differential transformer of claim 1 , wherein the stator further defines a plurality of slots configured to allow the coils to be installed along the stator.

7. The rotary variable differential transformer of claim 6 , wherein each of the slots on the stator are between 0.02 and 0.100 inches wide.

8. The rotary variable differential transformer of claim 1 , wherein the rotor defines:
a magnetically permeable arcuate section of the rotor configured around less than an entire circumference of the rotor, such that the magnetically permeable arcuate section allows for the electromagnetic coupling between the first primary coil and the secondary coils.

9. The rotary variable differential transformer of claim 8 , wherein the magnetically permeable arcuate section is between about 180 and 270 degrees of the entire circumference of the rotor.

Assignees

• Honeywell Int Inc

Inventors

• Sanchihar Paresh
• Esakki Subramanian
• Araganji Vijayshekhar

Classifications

• H01F21/04 Primary

  by relative movement of turns or parts of windings · CPC title

• G01D5/2291

  Linear or rotary variable differential transformers (LVDTs/RVDTs) having a single primary coil and two secondary coils · CPC title

• H01F27/02

  Casings · CPC title

• H01F27/28

  Coils; Windings; Conductive connections · CPC title

• H01F41/02

  for manufacturing cores, coils, or magnets (H01F41/14 takes precedence; for dynamo-electric machines H02K15/00) · CPC title