Magnetoresistive Speed Sensor

• US 20080246465A1
• Filed: 12/20/2004
• Published: 10/09/2008
• Est. Priority Date: 01/08/2004
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Butzmann, Stefan
• Granted Patent: US 7,615,994 B2
• Time in Patent Office: Days
• US Class Current: 324/174
• 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: G01P 3/488 delivered by variable reluctance detectors

Abstract

In order to create a magnetoresistive speed sensor (100) with a permanent magnet (10) and with a sensor (A, B) for a magnetic field for detecting the speed of an object rotating about an x-axis, wherein the magnetoresistive speed sensor (100) is equipped with a measuring direction (ME), in which an external magnetic interference field does not influence the measurement result, it is proposed that the measuring direction (ME) is aligned to be parallel with an x-direction and that two sensors (A, B) are disposed with displacement from one another and normal to the measuring direction (ME).

Claims

1. A magnetoresistive speed sensor a comprising a permanent magnet and a magnetic field detecting sensor for detecting the speed of an object rotating about an x-axis, wherein ______the magnetoresistive speed sensor has a measuring direction, characterized in that the measuring direction is aligned parallel with the x-direction, and two magnetic field detecting sensors are disposed at a distance from one another and perpendicular to the measuring direction.

2. A magnetoresistive speed sensor as claimed in claim 1, characterized in that the magnetic field detecting sensors are disposed symmetrically in relation to the x-axis on the y-axis.

3. A magnetoresistive speed sensor as claimed in claim 1, characterized in that each of the magnetic field detecting sensors is a Wheatstone bridge.

4. A magnetoresistive speed sensor as claimed in claim 1, characterized in that each of the magnetic field detecting sensors is a half bridge.

5. A magnetoresistive speed sensor as claimed in claim 1, characterized in that the permanent magnet has a magnetic field component in the x-direction.

6. A use of a magnetoresistive speed sensor as claimed in claim 1, in automotive engineering.

7. The use of a magnetoresistive speed sensor as recited in claim 6, wherein the automotive engineering includes at least one of the following:

crankshaft speed monitoring, camshaft speed monitoring, or monitoring of an anti-lock braking (ABS) system.

8. A magnetoresistive speed sensor comprising a permanent magnet and a magnetic field detecting sensor for detecting the speed of an object rotating about an x-axis, wherein

the magnetoresistive speed sensor has a measuring direction, characterized in that the measuring direction is aligned parallel with the x-direction, and two magnetic field detecting sensors are disposed at a distance from one another symmetrically in relation to the x-axis on the y-axis and perpendicular to the measuring direction.

9. The magnetoresistive speed sensor as recited in claim 8, wherein each of the magnetic field detecting sensors is a Wheatstone bridge.

10. The magnetoresistive speed sensor as recited in claim 8 wherein each of the magnetic field detecting sensors is a half bridge.

11. The magnetoresistive speed as recited in claim 8, wherein the permanent magnet has a magnetic field component in the x-direction.

12. The magnetoresistive speed as recited in claim 9, wherein the permanent magnet has a magnetic field component in the x-direction.

13. The magnetoresistive speed as recited in claim 10, wherein the permanent magnet has a magnetic field component in the x-direction.

14. A magnetoresistive speed sensor comprising,

a permanent magnet having a magnetic field component in the x-direction;

and

a magnetic field detecting sensor for detecting the speed of an object rotating about an x-axis, the magnetic field detecting sensor being a Wheatstone bridge, wherein

the magnetoresistive speed sensor has a measuring direction, characterized in that the measuring direction is aligned parallel with the x-direction, and two magnetic field detecting sensors are disposed at a distance from one another symmetrically in relation to the x-axis on the y-axis and perpendicular to the measuring direction.