Magnetoresistive angular position sensor and rotation speed sens

Details Magnetoresistive angular position sensor and rotation speed sens Magnetoresistive angular position sensor and rotation speed sens

1996-10-30

1998-08-18

Strecker, Gerard R.

Electricity: measuring and testing

Magnetic

Displacement

324174, 324252, G01B 730, G01P 3487, G01R 3309, G01D 512

Patent

active

057962499

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention relates to an angular position sensor and a rotation speed sensor, as applied over a wide range of techniques for non-contacting measurement of angles and speed of rotation, respectively.
There are three constructions which employ magnetoresistive strip lines arranged in a Wheatstone bridge pattern for measuring magnetic fields concerning magnitude and direction shown in German Patents DD 256 628 and DE 43 17 512. Conventionally, magneto-resistive strip lines are provided with so called Barber poles which permit the magnetoresistive strip lines to be arranged in parallel to one another which in turn reduces external electromagnetic interferences.
The manufacture of such Barber poles not only requires additional costs but also involves considerable technological requirements to obtain identical properties with respect to the poles relative to one another.
It has been proposed to realize the measuring objective (Peterson, A.:
"Sensoren zum Messen mechanischer GroBen im Kfz", meeting paper, Essen, Feb., 14th and 15th, 1995) by using two mutually displaced Wheatstone bridges in which the sensing strip lines are made of magnetoresistive material.
The proposed solution requires that the strip lines, relative to the current flow direction in the strip line, be arranged in rotational symmetry relative to an axis of rotation corresponding to a rotation axis of a permanent magnet rotating above the strip lines. Such an arrangement is disadvantageous because additional electrical signals indicative of different angular positions can only be obtained electronically under the condition of specific assumptions.


SUMMARY OF THE INVENTION

It is an object of the invention to provide an angular position sensor and/or rotation speed sensor, comprising a permanent magnet rotating about an axis and a plurality of Wheatstone bridges, the measurement bridges of which are formed of four magnetoresistive strip lines each, embodied in thin-film technique, which are arranged in planes parallel to a rotation plane of the permanent magnet which is comparatively simple to manufacture and which produces signals for angle detection which can be electronically and uniquely obtained thus providing ease of evaluation.
Briefly stated, the present invention provides a sensor for sensing at least one of angular position and rotation speed, the sensor comprising a permanent magnet rotatable about an axis of rotation and at least three Wheatstone bridges each having four bridge resistors formed of magnetoresistive strip lines extending in planes parallel to a rotation plane of the permanent magnet. The bridge resistors of each of the at least three Wheatstone bridges are disposed on respective sides of quadrangles corresponding to respective ones of the at least three Wheatstone bridges. Each of the at least three Wheatstone bridges has two adjacently arranged ones of the bridge resistors connected to a half-bridge of respective ones of the at least three Wheatstone bridges. The quadrangles are disposed relative to one another rotated by a preselectable angle .alpha.. The at least three Wheatstone bridges each have an intersection point of virtual diagonals connecting corners of respective ones of the quadrangles, the intersection points being arranged substantially concentrically about the axis of rotation, and the at least three Wheatstone bridges are disposed so as to be equally and evenly swept by a field of the permanent magnet during rotation thereof to saturate the bridge resistors.
According to a feature of the invention, the intersection points are coaxially arranged to coincide with one another and with the axis of rotation of the permanent magnet.
By virtue of the embodiment of the magneto-resistive strip lines as a Wheatstone bridge and the defined arrangement of at least three of such bridges, it is feasible to obtain separate electrical signals from the Wheatstone bridges rotationally displaced relative to one another by a definite angle. This permits the building-up of simple assemblies

REFERENCES:
patent: 5602471 (1997-02-01), Muth et al.
Peterson, A.: "Sensoren fuer beruehrungslosen Winkelmessung", meeting paper, Essen, Feb. 14th and 15th, 1995, with English abstract.

Affiliated with

Also associated with

Rating

Magnetoresistive angular position sensor and rotation speed sens does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Magnetoresistive angular position sensor and rotation speed sens, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetoresistive angular position sensor and rotation speed sens will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1117813