Sensor device for an electric machine

• US 8,063,628 B2
• Filed: 02/21/2007
• Issued: 11/22/2011
• Est. Priority Date: 04/07/2006
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Finkler, Roland, Jajtic, Zeljko, Knorr, Markus
• Primary Examiner(s): Hollington, Jermele M
• Application Number:
  US12/296,352
• Publication Number:
  US 20090284253A1
• Time in Patent Office: 1,735 Days
• Field of Search: None
• US Class Current: 324/207.24
• CPC Class Codes: G01D 2205/40 Position sensors comprising arrangements for concentrating or redirecting magnetic flux
• CPC Class Codes: G01D 5/147 influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other
• CPC Class Codes: G01D 5/2046 by a movable ferromagnetic element, e.g. a core

Abstract

The aim of the invention is to create an inexpensive sensor system for a movable electric machine in order to determine positions, the sensor signal featuring zero crossings. Said aim is achieved by a sensor device (1) comprising a U-shaped yoke (3) and a sensor (10) which is disposed in/on the yoke (3) to detect a magnetic variable, for example. Magnets (6 to 9) that are or can be inversely magnetized are arranged at a free end of the yoke (3). Opposite magnetic fluxes that can be detected by the sensor (10) can be generated in the yoke (3) in accordance with the position of the magnets (6 to 9) relative to one of the pole teeth (11, 12, 13) of a machine component. Approximately sinusoidal sensor signals can be generated therefrom without having to use several measuring sensors, e.g. in order to regulate a linear motor.

Claims

1. A sensor device for detecting a position or a movement relative to a machine component of an electric machine having pole teeth, the sensor comprising:

a U-shaped yoke section having opposing free ends, and

a sensor arranged in or on the yoke section for measuring a magnetic variable, and

two magnets having opposite polarity arranged on each of the opposing free ends of the yoke section, with a magnet of one polarity disposed on one end of the yoke section in cooperation with a magnet of opposite polarity on the other end of the yoke section producing in the yoke section a magnetic flux depending on a position of the two magnets in relation to an opposing pole tooth, with a flux direction in the yoke section depending on the polarity of the two cooperating magnets that oppose the opposing pole teeth.

2. The sensor device of claim 1, wherein the sensor comprises a Hall sensor.

3. The sensor device of claim 1, wherein the sensor comprises a measuring coil wound around the yoke section.

4. The sensor device of claim 1, wherein the magnets arranged on the free end of the yoke section are permanent magnets.

7. The sensor device of claim 1, wherein the two magnets are arranged consecutively in a movement direction of the sensor device relative to the machine component.

5. A sensor device for detecting a position or a movement relative to a machine component of an electric machine having pole teeth, the sensor comprising:

a U-shaped yoke section having opposing free ends and an additional center limb integrally formed on the yoke section, thereby producing an E-shaped yoke section,

a sensor arranged in or on the yoke section for measuring a magnetic variable, and

two magnets having opposite polarity arranged on the additional center limb of the yoke section and producing in the yoke section a magnetic flux depending on a position of the two magnets in relation to an opposing pole tooth, with a flux direction in the yoke section depending on the polarity of the magnet that opposes the pole tooth.

6. The sensor device of claim 5, wherein the sensor is arranged in or on the center limb of the E-shaped yoke section.

8. A sensor device for detecting a position or a movement relative to a machine component of an electric machine having pole teeth, the sensor comprising:

a U-shaped yoke section having opposing free ends, and

a magnet device arranged in or on the yoke section for producing in the yoke section a magnetic flux having a flux direction, and

a sensor having two sensor elements arranged on each of the opposing free ends of the yoke section for measuring a magnetic variable,

wherein a sensor element disposed on one end of the yoke section in cooperation with a sensor element disposed on the other end of the yoke section produce for a given magnetic flux direction in the yoke section voltages of different polarity in the cooperating sensor elements, with a magnitude of the produced voltages depending on a position of the cooperating sensor elements in relation to an opposing pole tooth.

9. The sensor device of claim 8, the two sensor elements comprise Hall sensors.

10. The sensor device of claim 8, the two sensor elements comprise measuring coils.

11. The sensor device of claim 8, wherein the U-shaped yoke section comprises an additional center limb integrally formed on the yoke section, thereby producing an E-shaped yoke section, with the magnet device being arranged on the free end of the additional center limb.

12. The sensor device of claim 8, wherein two sensor elements are arranged on each of the free ends of the yoke section.

13. A sensor device for detecting a position or a movement relative to a machine component of an electric machine having pole teeth, the sensor comprising:

an E-shaped yoke having center limb and being symmetrically split along the center limb into two yoke parts transversely to a movement direction, with an air gap separating the two yoke parts,

a sensor arranged in the air gap of the center limb for measuring a magnetic variable, and

a magnet bridging free ends of the two yoke parts of the center limb.

14. The sensor device of claim 13, wherein the sensor comprises a Hall sensor.

15. The sensor device of claim 13, wherein the sensor comprises a measuring coil wound around the yoke section.

16. The sensor device of claim 13, wherein the magnet bridging the free ends is a permanent magnet.

17. An electric machine comprising a sensor device for detecting a position or a movement relative to a machine component of the electric machine having pole teeth, the sensor comprising:

a U-shaped yoke section having opposing free ends, and

a sensor arranged in or on the yoke section for measuring a magnetic variable, and

two magnets having opposite polarity arranged on each of the opposing free ends of the yoke section, with a magnet of one polarity disposed on one end of the yoke section in cooperation with a magnet of opposite polarity on the other end of the yoke section producing in the yoke section a magnetic flux depending on a position of the two magnets in relation to an opposing pole tooth, with a flux direction in the yoke section depending on the polarity of the two cooperating magnets that oppose the opposing pole teeth.

18. The electric machine of claim 17 wherein the electric machine is implemented as a linear motor having a primary part and a secondary machine part, with the machine component having the pole teeth forming a secondary machine part and the sensor device being fastened to or being a part of the primary part.

19. An electric machine comprising a sensor device for detecting a position or a movement relative to a machine component of an electric machine having pole teeth, the sensor comprising:

a U-shaped yoke section having opposing free ends, and

a magnet device arranged in or on the yoke section for producing in the yoke section a magnetic flux having a flux direction, and

a sensor having two sensor elements arranged on each of the opposing free ends of the yoke section for measuring a magnetic variable,

wherein a sensor element disposed on one end of the yoke section in cooperation with a sensor element disposed on the other end of the yoke section produce for a given magnetic flux direction in the yoke section voltages of different polarity in the cooperating sensor elements, with a magnitude of the produced voltages depending on a position of the cooperating sensor elements in relation to an opposing pole tooth.

20. The electric machine of claim 19 wherein the electric machine is implemented as a linear motor having a primary part and a secondary machine part, with the machine component having the pole teeth forming a secondary machine part and the sensor device being fastened to or being a part of the primary part.

21. An electric machine comprising a sensor device for detecting a position or a movement relative to a machine component of an electric machine having pole teeth, the sensor comprising:

an E-shaped yoke having center limb and being symmetrically split along the center limb into two yoke parts transversely to a movement direction, with an air gap separating the two yoke parts,

a sensor arranged in the air gap of the center limb for measuring a magnetic variable, and

a magnet bridging free ends of the two yoke parts of the center limb.

22. The electric machine of claim 21 wherein the electric machine is implemented as a linear motor having a primary part and a secondary machine part, with the machine component having the pole teeth forming a secondary machine part and the sensor device being fastened to or being a part of the primary part.