Magnetic Field Sensitive Sensor

• US 20090161264A1
• Filed: 10/10/2008
• Published: 06/25/2009
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: Woelke Magnetbandtechnik GmbH & Co. KG.
• Original Assignee: Woelke Magnetbandtechnik GmbH & Co. KG.
• Inventors: Meyersweissflog, Stefan
• Granted Patent: US 8,022,693 B2
• Time in Patent Office: Days
• US Class Current: 360/324
• CPC Class Codes: G01D 11/245 Housings for sensors
• 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 5/2451 Incremental encoders G01D5/2454 takes precedence

Abstract

The present invention relates to a sensor, preferably for magnetic rotary or linear sensor systems which include a scale arranged at a given distance from the sensor, with at least one magnetic field-sensitive GMR sensor element which is arranged in a housing, wherein the housing additionally includes one magnetic field source each associated to the at least one GMR sensor element, wherein the at least one GMR sensor element is firmly cast into an associated slot in the housing, wherein on at least one side of the slot a projection protrudes into the interior of the housing flush with this side wall of the slot, which also includes mounting recesses for accommodating the magnetic field source.

Claims

1. A sensor comprising at least one magnetic field-sensitive GMR sensor element which is arranged in a housing, wherein the housing additionally includes one magnetic field source each associated to the at least one GMR sensor element,

wherein the at least one GMR sensor element is firmly cast into an associated slot in the housing, wherein on at least one side of the slot a projection protrudes into an interior of the housing flush with a side wall of the slot, the projection including mounting recesses for accommodating the magnetic field source.

2. The sensor according to claim 1, wherein the at least one GMR sensor element is associated to a reference signal track in a scale for generating a reference signal, the scale arranged at a given distance from the sensor.

3. The sensor according to claim 2, wherein the GMR sensor element contains two basic sensor elements, which are each associated to respective incremental reference signal tracks such that they generate two phase-shifted signals.

4. The sensor according to claim 3, wherein the magnetic field source comprises at least one permanent magnet.

5. The sensor according to claim 4, wherein the permanent magnet is cuboidal, wherein its dimensions relative to the associated GMR sensor element are such that a largely homogeneous magnetic field acts on the GMR sensor element.

6. The sensor according to claim 1, wherein the housing is made of aluminum.

7. The sensor according to claim 1, wherein in the at least one slot an encapsulated sensor element is inserted.

8. The sensor according to claim 1, wherein in the at least one slot a non-encapsulated sensor element is inserted.

9. The sensor according to claim 1, wherein the slot is longer than a length of the magnetic field-sensitive GMR sensor element.

10. The sensor according to claim 1, wherein the housing has a substantially two-part design.

11. The sensor according to claim 1 further comprising a circuit board arranged inside the housing, the circuit board including processing electronics, wherein the circuit board is L-shaped.

12. The sensor according to claim 1, wherein two GMR sensors and a magnetic field source associated to each sensor are inserted in the housing in a fixed association relative to each other.

13. The sensor according to claim 1 further comprising a supply cable, wherein the supply cable of the sensor is screwed into a thread of the housing for strain relief via its outside insulation.

14. A system comprising:

a magnetic sensor comprising at least one magnetic field-sensitive GMR sensor element which is arranged in a housing, wherein the housing additionally includes one magnetic field source each associated to the at least one GMR sensor element, wherein the at least one GMR sensor element is firmly cast into an associated slot in the housing, wherein on at least one side of the slot a projection protrudes into an interior of the housing flush with a side wall of the slot, the projection including mounting recesses for accommodating the magnetic field source; and

a scale arranged at a given distance from the sensor, the scale including a reference track associated with the sensor element.

15. A sensor comprising:

a sensor housing including a first and second slot, each slot including at least one side defined by a side wall on an elongate side of the slot, the side wall having a surface, the elongate sides of the slots each including a projection that protrudes into an interior of the housing, the projections flush with the respective surfaces of the side walls of the slots;

a first and second magnetic field-sensitive GMR sensor element firmly cast into the respective slots in the housing; and

a first and second magnetic field source associated to the respective first and second sensor elements, the sources each arranged in the housing, wherein each of the projections include a mounting recess shaped to accommodate the respective magnetic field sources and to position the respective magnetic field sources relative to the respective sensor elements and the housing.

16. The sensor according to claim 15 wherein the at least one GMR sensor element is associated to a reference signal track in a scale for generating a reference signal.

17. The sensor according to claim 16 wherein the GMR sensor element contains two basic sensor elements, which are each associated to respective incremental reference signal tracks such that they generate two phase-shifted signals.

18. The sensor according to claim 17 wherein the magnetic field source comprises at least one permanent magnet.