Torque sensor with mathematically smooth claws

Patent metadata

Field	Value
Publication number	US-10551259-B2
Application number	US-201815987263-A
Country	US
Kind code	B2
Filing date	May 23, 2018
Priority date	May 23, 2017
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

A stator to guide a location-dependent magnetic field in a circumferential direction around a rotation axis. In one example, the stator includes a first stator ring revolving around the rotation axis, and a second stator ring revolving around the rotation axis and arranged concentrically with the first stator ring. The first and second stator rings include claws which are arranged so as to revolve around the rotation axis and at a distance from one another in the circumferential direction and engage with one another at least on a toothing axial plane. The claws are separated from one another by an air gap so that, when the magnetic field is arranged in the toothing axial plane, the magnetic field is guided towards the stator rings via the claws according to a relative angular position. Each claw has the contour of a mathematically smooth curve when viewed across the circumferential direction.

First claim

The invention claimed is:

1. A stator to guide a location-dependent magnetic field in a circumferential direction around a rotation axis, said stator comprising:
a first stator ring revolving around the rotation axis, and
a second stator ring revolving around the rotation axis, which is arranged concentrically with the first stator ring,
the first and second stator ring including claws which are arranged so as to revolve around the rotation axis and at a distance from one another in the circumferential direction and engage with one another at least on a toothing axial plane, said claws being separated from one another by an air gap in such a way that, when the magnetic field is arranged in the toothing axial plane, the magnetic field is guided towards the stator rings via the claws according to a relative angular position,

wherein
each claw has the contour of a mathematically smooth curve when viewed across the circumferential direction, wherein each claw has a base, above which a head is supported on the respective stator ring, said head being smaller than the base when viewed in the circumferential direction, and the base and the head merge with one another in a transition region having a curve which is negative starting from a base curve.

2. The stator as claimed in claim 1 , wherein the base curve and the curve of the transition region have the same dimensions.

3. The stator as claimed in claim 1 , wherein the head, when viewed in the circumferential direction, has an extension which is between a quarter and three quarters of the extension of the base in the circumferential direction.

4. The stator as claimed in claim 1 , wherein regions of the base and the head have circular or oval designs.

5. The stator as claimed in claim 1 , wherein the claws are arranged axis-symmetrically to one another in the circumferential direction on each stator ring.

6. The stator as claimed in claim 1 , wherein the claws are arranged point-symmetrically to one another in the circumferential direction between the stator rings.

7. The stator as claimed in claim 1 , wherein the edges of each claw are arranged at a right angle to a stator axial plane which is different from the toothing axial plane, in which their respective stator ring is positioned.

8. A sensor to detect a torque between a first shaft and a second shaft, which are interconnected by a torsion bar, the sensor comprising:
a stator connected to the first shaft; the stator including
a first stator ring revolving around a rotation axis, and
a second stator ring revolving around the rotation axis, which is arranged concentrically with the first stator ring,
the first and second stator ring including claws which are arranged so as to revolve around the rotation axis and at a distance from one another in the circumferential direction and engage with one another at least on a toothing axial plane, said claws being separated from one another by an air gap in such a way that, when the magnetic field is arranged in the toothing axial plane, the magnetic field is guided towards the stator rings via the claws according to a relative angular position,
wherein
each claw has the contour of a mathematically smooth curve when viewed across the circumferential direction;

a magnetic field generator connected to the second shaft, and which is arranged co-axially with the rotation axis to generate and feed the magnetic field into the stator, and
a magnetic field sensor to detect a magnetic field from the magnetic field generator passing the stator, wherein each claw has a base, above which a head is supported on the respective stator ring, said head being smaller than the base when viewed in the circumferential direction, and the base and the head merge with one another in a transition region having a curve which is negative starting from a base curve.

9. The sensor as claimed in claim 8 , wherein the base curve and the curve of the transition region have the same dimensions.

10. The sensor as claimed in claim 8 , wherein the head, when viewed in the circumferential direction, has an extension which is between a quarter and three quarters of the extension of the base in the circumferential direction.

11. The sensor as claimed in claim 8 , wherein regions of the base and the head have circular or oval designs.

12. The sensor as claimed in claim 8 , wherein the claws are arranged axis-symmetrically to one another in the circumferential direction on each stator ring.

13. The sensor as claimed in claim 8 , wherein the claws are arranged point-symmetrically to one another in the circumferential direction between the stator rings.

14. The sensor as claimed in claim 8 , wherein the edges of each claw are arranged at a right angle to a stator axial plane which is different from the toothing axial plane, in which their respective stator ring is positioned.

Assignees

• Bourns Inc

Inventors

• Berner Sebastian
• Pichler Benno
• Sommer Andreas

Classifications

• B62D5/0481

  monitoring the steering system, e.g. failures · CPC title

• G01L5/221 Primary

  to steering wheels, e.g. for power assisted steering · CPC title

• B62D5/0409

  Electric motor acting on the steering column · CPC title

• G01L3/101 Primary

  involving magnetic or electromagnetic means · CPC title

• G01L5/0009 Primary

  Force sensors associated with a bearing (testing of bearings G01M13/04) · CPC title