Magnetic position detector with multiple magnetoeffect resistance elements

• US 5,216,363 A
• Filed: 03/04/1992
• Issued: 06/01/1993
• Est. Priority Date: 03/14/1991
• Status: Expired due to Term

• Current Assignee: MORI Seiki Company Limited
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Masaaki, Kusumi
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US07/845,951
• Time in Patent Office: 454 Days
• Field of Search: 324/207.2, 324/207.21, 324/235, 324/251, 324/252, 324/207.24, 324/207.25, 338/32 R, 338/32 H
• US Class Current: 324/207.21
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A magnetic sensor disposed in an opposing relation to a magnetic scale magnetized at a grating pitch λ in the length direction thereof and which is movable relative to the magnetic scale in the length direction is comprised of at least two magnetoeffect resistance elements disposed with a distance of (λ/2)·n (n=1, 2, 3, . . . ) in the length direction, the two magnetoeffect resistance elements being formed in the width direction perpendicular to the length direction and each of the magnetoeffect resistance elements having partial magnetoeffect resistance elements distant from each other by a distance of (λ/2)·(1/2m) (m=2, 3, 4, . . . ) from a predetermined position on the width direction perpendicular to the length direction, wherein the two magnetoeffect resistance elements are shaped as substantially symmetrical configurations relative to a central line in the length direction.

Claims

1. A magnetic sensor disposed in an opposing relation to a magnetic scale magnetized at a grating pitch λ

in its length direction and which is movable relative to said magnetic scale in its length direction comprising;

at least one pair of magnetoeffect resistance elements;

said pair of magnetoeffect resistance elements being arranged in the width direction perpendicular to said length direction and each of said magnetoeffect resistance elements being formed of a first partial magnetoeffect resistance element and an electrically connected second partial magnetoeffect resistance element;

said first partial magnetoeffect resistance element and said second partial magnetoeffect resistance element arranged substantially parallel to each other and offset by a distance of (λ

/2)·

(1/2m) (m=2, 3, 4, . . . ) in said length direction, wherein said pair of magnetoeffect resistance elements are disposed with distance of (λ

/2) n (n=1, 2, 3, . . . ) between said first partial magnetoeffect resistance element of a first one of said pair of magnetoeffect resistance elements and said second partial magnetoeffect resistance element of a second one of said pair of magnetoeffect resistance elements in said length direction, and wherein said pair of magnetoeffect resistance elements are shaped as substantially symmetrical configuration so as to be mirror images of each other relative to a central line perpendicular to said length direction, whereby an output of at least one pair of said magnetoeffect resistance elements is maximized and a distortion of said output of said magnetoeffect resistance elements is minimized at a given angle relative to said magnetic scale.

2. A magnetic sensor disposed in an opposing relation to a magnetic scale magnetized at a grating pitch λ

in its length direction and which is movable relative to said magnetic scale in its length direction comprising;

at least two pairs of magnetoeffect resistance elements disposed in the direction perpendicular to said length direction by a predetermined distance and offset by a distance of λ

/4 in said length direction between said pairs;

each of said magnetoeffect resistance elements being formed of a first partial magnetoeffect resistance element and an electrically connected second partial magnetoeffect resistance element;

said first partial magnetoeffect resistance element and said second partial magnetoeffect resistance element arranged substantially parallel to each other and offset by a distance of (λ

/2)·

(1/2m) (m=2, 3, 4, . . . ) in said length direction, wherein each pair of said magnetoeffect resistance elements are shaped as substantially symmetrical configurations so as to form mirror images relative to a central line perpendicular to said length direction and a first partial magnetoeffect resistance element of a first one of each pair of magnetoeffect resistance elements is offset by a distance of (λ

/2)·

(1/2m) (m=2, 3, 4, . . . ) in said length direction from a second partial magnetoeffect resistance element of a second one of each pair of magnetoeffect resistance elements, whereby an output of said magnetoeffect resistance elements is maximized and a distortion of said output of said magnetoeffect resistance elements is minimized at a given angle relative to said magnetic scale.