Device for detecting the twist angle of a shaft and/or a torque occurring on the shaft and methods for operating the device

Patent metadata

Field	Value
Publication number	US-9026378-B2
Application number	US-201113136817-A
Country	US
Kind code	B2
Filing date	Aug 11, 2011
Priority date	Aug 13, 2010
Publication date	May 5, 2015
Grant date	May 5, 2015

Abstract

A device for detecting a twist angle and/or a torque of a shaft occurring on the shaft and methods for operating the device uses at least one first encoder and at least one second encoder at a predefined spacing therefrom. Each encoder influences at least one coil parameter, is associated with at least a part of the circumference of the shaft, and has at least one track having at least one period per revolution of the shaft. At least first and second inductive sensors scan the first and second encoders, respectively. Each inductive sensor provides a respective sensor signal reflecting at least one measure for the rotational angle of the shaft within the period, and a difference ascertainment unit ascertains and provides the twist angle of the shaft as an angle difference of the two rotational angles detected by the inductive sensors.

First claim

What is claimed is:

1. A device for detecting a twist angle of a shaft and/or a torque occurring on the shaft, the device comprising:
at least one first passive encoder associated with at least a part of the circumference of the shaft, influencing at least one first coil parameter, and having at least one first encoder track having at least one period per revolution of the shaft,
at least one first inductive proximity sensor for scanning the at least one first passive encoder and providing a first rotational angle of the shaft within the period,
at least one second passive encoder also associated with at least a part of the circumference of the shaft, influencing at least one second coil parameter, being provided at a predefined spacing to the at least one first passive encoder, and having at least one second encoder track having at least one period per revolution of the shaft,
at least one second inductive proximity sensor for scanning the at least one second passive encoder and also providing a second sensor signal reflecting at least one measure for a second rotational angle of the shaft within the period, and
a difference ascertainment unit ascertaining and providing the twist angle of the shaft as an angle difference of the first rotational angles detected by the at least one first inductive proximity sensors and the second rotational angle detected by the at least one second inductive proximity sensor;
wherein the at least one first encoder track extends without pitch only in the circumferential direction of the shaft and contains a plurality of repeating periods;
wherein the at least one first inductive proximity sensor comprises a first first inductive proximity sensor and a second first inductive proximity sensor;
wherein the first first inductive proximity sensor and the second first inductive proximity sensor are associated with the at least one first encoder track;
wherein the first first inductive proximity sensor and the second first inductive proximity sensor are positioned in relation to the periods of the at least one first encoder track such that the first first inductive proximity sensor provides a first first sensor signal phase-shifted by at least approximately 90°in relation to a second first sensor signal provided by the second first inductive proximity sensor;
wherein the at least one first encoder track comprises a first first encoder track and a second first encoder track directly adjacent to the first first encoder track;
wherein the first first encoder track contains a first predefined number greater than one of repeating periods;
wherein the second first encoder track has a second predefined number of repeating periods; and
wherein the second predefined number deviates by at least one from the first predefined number.

2. The device according to claim 1 , wherein the at least one first encoder track is wound mirror-inverted in relation to the at least one second encoder track with respect to the longitudinal direction of the shaft.

3. The device according to claim 1 , wherein the period of the at least one track of the first encoder track and/or of the at least one second encoder track is implemented as a web or groove of modulated width and/or height.

4. The device according to claim 1 , wherein the period of the at least one first encoder track and/or of the at least one second encoder track is implemented as a web having sinusoidally modulated width.

5. The device according to claim 1 , wherein the period of the at least one first encoder track and the period of the at least one second encoder track is implemented as a web having at least sectionally sinusoidally modulated width.

6. The device according to claim 1 , wherein the period of the at least one second encoder track and/or of the at least one second encoder track is implemented as a cam.

7. The device according to claim 1 , wherein the period of the at least one first encoder track and/or of the at least one second encoder track is implemented as a recess.

8. The device according to claim 1 , wherein the device further comprises a third first inductive proximity sensor and a fourth first inductive proximity sensor each associated with the second first encoder track and positioned in relation to the period of the second first encoder track such that the third first inductive proximity sensor provides a third first sensor signal which is phase-shifted by at least approximately 90 ° in relation to a fourth first sensor signal provided by the fourth first inductive proximity sensor.

9. A shaft of a transmission comprising a device for detecting a twist angle of the shaft and/or a torque occurring on the shaft, the device comprising:
at least one first passive encoder associated with at least a part of the circumference of the shaft, influencing at least one first coil parameter, and having at least one first encoder track having at least one period per revolution of the shaft,
at least one first inductive proximity sensor for scanning the at least one first passive encoder and providing a first sensor signal reflecting at least one measure for a first rotational angle of the shaft within the period,
at least one second passive encoder also associated with at least a part of the circumference of the shaft, influencing at least one second coil parameter, being provided at a predefined spacing to the at least one first passive encoder, and having at least one second encoder track having at least one period per revolution of the shaft,
at least one second inductive proximity sensor for scanning the at least one second passive encoder and also providing a second sensor signal reflecting at least one measure for a second rotational angle of the shaft within the period, and
a difference ascertainment unit ascertaining and providing the twist angle of the shaft as an angle difference of the first rotational angle detected by the at least one first inductive proximity sensor and the second rotational angle detected by the at least one second inductive proximity sensor;
wherein the at least one first encoder track extends without pitch only in the circumferential direction of the shaft and contains a plurality of repeating periods;
wherein the at least one first inductive proximity sensor comprises a first first inductive proximity sensor and a second first inductive proximity sensor;
wherein the first first inductive proximity sensor and the second first inductive proximity sensor are associated with the at least one first encode track;
wherein the first first inductive proximity sensor and the second first inductive proximity sensor are positioned in relation to the periods of the at least one first encoder track such that the first first inductive proximity sensor provides a first first sensor signal phase-shifted by at least approximately 90 ° in relation to a second first sensor signal provided by the second first inductive proximity sensor;
wherein the at least one first encoder track comprises a first first encoder track and a second first encoder track directly adjacent to the first first encoder track;
wherein the first first encoder track contains a first predefined number greater than one of repeating periods;
wherein the second first encoder track has a second predefined number of repeating periods; and
wherein the second predefined number deviates by at least one from the first predefined number.

10. A method for detecting a torque of a shaft, the method comprising steps of:
providing the shaft and a device, the device comprising:
at least one first passive encoder associated with at least a part of a circumference of the shaft, influencing at least one first coil parameter, and having at least one first enc

Assignees

• Fericean Sorin
• Hiller-Brod Andrea
• Droxler Reinhard
• Fritton Markus
• Kraeter Daniel
• Balluff Gmbh

Inventors

• Fericean Sorin
• Hiller-Brod Andrea
• Droxler Reinhard
• Fritton Markus
• Kraeter Daniel

Classifications

• G01L3/105 Primary

  involving inductive means (G01L3/102, G01L3/104 take precedence) · CPC title

• G01D5/202 Primary

  by movable a non-ferromagnetic conductive element (G01D5/2033 takes precedence) · CPC title

• G01D5/20

  by varying inductance, e.g. by a movable armature · CPC title

• G01L25/003

  for measuring torque · CPC title

• G01L3/109

  involving measuring phase difference of two signals or pulse trains · CPC title