Linear and rotary magnetic sensor

• US 6,600,310 B2
• Filed: 03/07/2001
• Issued: 07/29/2003
• Est. Priority Date: 03/08/2000
• Status: Expired due to Term

• Current Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Original Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Inventors: Russell, Lawrence J., Togneri, Mauro G., Nyce, David S.
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US09/801,318
• Publication Number:
  US 20010038281A1
• Time in Patent Office: 874 Days
• Field of Search: 324/207.13, 324/207.14, 324/207--20, 116/28.1, 335/302, 335/306, 733/13, 733/14, 732/90.V, 735/97, 743/35, 744/731.2, 74D/IG.7, 340/456, 340/686.3, 477/20, 475/158
• US Class Current: 324/207.23
• CPC Class Codes: F16H 59/70 dependent on the ratio established
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• 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 5/485 using magnetostrictive devices
• CPC Class Codes: Y10T 74/2003 Electrical actuator

Abstract

A magnetic-based sensor is disclosed which can detect a linear and rotary position of a shaft whose movement is to be measured. Such sensor can operate to yield linear displacement as well as rotation. A position magnet is mounted on the shaft for measuring linear motion. A spirally wound magnet is mounted on the shaft to detect rotational motion. Both of such motions are detected by a single magnetic-based sensor.

Claims

1. A sensor for detecting linear and rotary motion of a workpiece, comprising:

a first magnet mounted on the workpiece;

a sensor using said first magnet for detecting rotary motion of the workpiece;

said first magnet being spirally mounted on at least a portion of the workpiece and juxtaposed to at least a portion of said sensor;

wherein there is a second magnet mounted on the workpiece, said sensor using said second magnet for detecting linear motion of the workpiece;

said second magnet being mounted to circumscribe at least a portion of the workpiece and juxtaposed to at least a portion of said sensor.

2. The sensor of claim 1, wherein said sensor is mounted substantially parallel to at least a portion of the workpiece where said first magnet and such second magnet are mounted.

3. The sensor of claim 2, wherein said sensor is juxtaposed to at least a portion of the workpiece to which it is substantially parallel.

18. The sensor of claim 1, wherein a plane substantially passing through said second magnet would be intersected at a point by a line passing through the axis of rotation of the workpiece.

19. The sensor of claim 1, wherein at least a portion of the longitudinal axis of said sensor is mounted substantially parallel to the rotation axis of the workpiece along substantially the full length of said first magnet.

20. The sensor of claim 1, wherein said second magnet is an annular magnet.

4. A sensor for detecting linear and rotary motion of a workpiece, comprising:

a first magnet mounted on the workpiece;

a sensor using said first magnet for detecting rotary motion of the workpiece, at least a portion of said sensor mounted substantially parallel to the rotation axis of the workpiece; and

said first magnet being spirally mounted on at least a portion of the workpiece and juxtaposed to at least a portion of said sensor;

wherein there is a second magnet mounted on the workpiece, said sensor using said second magnet for detecting linear motion of the workpiece;

said second magnet being mounted to circumscribe the circumference on at least a portion of the workpiece and juxtaposed to at least a portion of said sensor;

wherein said sensor is mounted substantially parallel to at least a portion of the workpiece where said first magnet and such second magnet are mounted;

wherein said sensor is juxtaposed to at least the portion of the workpiece to which it is substantially parallel;

wherein said sensor is a magnetostrictive sensor.

5. The sensor of claim 4, wherein said magnetostrictive sensor includes a waveguide and a mode converter, at least the portion of the workpiece on which said first magnet is mounted being juxtaposed to at least a portion of said waveguide.

6. The sensor of claim 5, wherein said second magnet is a position magnet for detecting linear motion.

7. The sensor of claim 6, wherein said second magnet is substantially doughnut-shaped.

8. The sensor of claim 7, wherein at least the portion of the workpiece on which said second magnet is mounted is juxtaposed to at least a portion of said waveguide.

9. A gear system sensor to detect gear position, the gear system including a rotary and linear motor connected to, and linear displacing and rotating, a shifter shaft which engages the appropriate gears, comprising:

a first magnet mounted on the shifter shaft;

a sensor using said first magnet for detecting rotary motion of the shifter shaft to determine the gear selected through the use of said first magnet on the shifter shaft, at least a portion of said sensor mounted juxtaposed to the shifter shaft on which said first magnet is mounted; and

said first magnet being spirally mounted on at least a portion of the portion of the shifter shaft juxtaposed to said magnet based sensor.

10. The sensor of claim 9, wherein there is further included a second magnet, said sensor detecting linear motion through the use of said second magnet;

said second magnet being mounted on at least a portion of the shifter shaft and juxtaposed to at least a portion of said sensor responsive to said second magnet.

11. The system of claim 10, wherein said sensor is a magnetostrictive sensor having a waveguide and a mode converter, the portion of the shifter shaft having said first magnet mounted thereon being juxtaposed to at least a portion of said waveguide.

12. The system of claim 11, wherein the portion of the shifter shaft having said first magnet mounted thereon also has said second magnet mounted thereon.

13. A sensor for detecting linear and rotary motion of a workpiece, comprising:

a first magnet mounted on the workpiece;

means for detecting rotary motion responsive to said first magnet, at least a portion of said means mounted substantially parallel to the rotation axis of the workpiece for the length of said first magnet; and

said first magnet being spirally mounted on at least a portion of the workpiece and juxtaposed to at least a portion of said means responsive to said first magnet.

14. The sensor of claim 13, wherein there is a second magnet mounted on the workpiece, said means for detecting linear motion responsive to said second magnet;

said second magnet being mounted on at least a portion of the workpiece and juxtaposed to at least a portion of said means responsive to said second magnet.

15. The sensor of claim 14, wherein said means is mounted substantially parallel to at least a portion of the workpiece where said first magnet and such second magnet are mounted.

16. The sensor of claim 15, wherein said means is juxtaposed to at least the portion of the workpiece to which it is substantially parallel.

17. Thee sensor of claim 16, wherein said means is a magnetostrictive sensor for nonmagenetic field strength detection.

21. A process for determining the linear and rotary displacement of a workpiece using a first magnet, the first magnet spirally mounted on the workpiece and a second annular magnet about at least a portion of the workpiece, comprising the steps of:

sensing the rotational location of the first magnet by the sensor;

sensing the linear location of the second magnet by the sensor;

determining the linear position of the workpiece from the second magnet;

determining the rotational position of the workpiece as the difference between the linear position of the workpiece and the position of the first magnet.