MAGNETIC POSITION DETECTION DEVICE AND MAGNETIC POSITION DETECTION METHOD
First Claim
1. A magnetic position detection device, comprising:
- a magnetized scale in which magnetic pole pairs each having a width 2λ and
each being formed of a first magnetic portion having a width λ and
a second magnetic portion having the width λ
, which have different magnetic properties, are arranged at equal pitches of a period of the magnetic pole pair width 2λ
;
a magnetosensitive device arranged so as to be opposed to the magnetized scale with a predetermined air gap therebetween, the magnetosensitive device being configured to move relatively in a direction of arrangement of the magnetized scale within a magnetic field formed by the magnetized scale while maintaining the air gap, and to measure a change of the magnetic field due to the relative movement with use of magnetosensitive elements; and
a position calculation circuit configured to analyze an output value of the magnetosensitive device, to thereby calculate a relative position between the magnetosensitive device and the magnetized scale,wherein the magnetosensitive device comprises, as the magnetosensitive elements, a first magnetosensitive element group in which n first magnetosensitive elements, where n is a natural number of 2 or more, are arranged at equal magnetosensitive element pitches P so that λ
=nP is established, and the n first magnetosensitive elements of the first magnetosensitive element group are configured to output results of measuring the change of the magnetic field due to the relative movement in parallel, andwherein the position calculation circuit analyzes output values that are output from the magnetosensitive device in parallel, to thereby calculate the relative position between the magnetosensitive device and the magnetized scale as a position detection resolution of λ
/n.
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Accused Products
Abstract
A magnetized scale (1a) in which magnetic pole pairs each formed of a first magnetic portion (11a) and a second magnetic portion (12a) having different magnetic properties are arranged with a period of a magnetic pole pair width 2λ, and a magnetosensitive device (2) in which n magnetosensitive elements (21a to 21e) are arranged with a magnetosensitive element pitch P so that λ=nP may be established are arranged so as to be opposed to each other with a predetermined air gap therebetween. Output values output from the n magnetosensitive elements (21a to 21e) in parallel are analyzed to calculate a relative position between the magnetosensitive device (2) and the magnetized scale (1a) as a position detection resolution of λ/n.
16 Citations
12 Claims
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1. A magnetic position detection device, comprising:
-
a magnetized scale in which magnetic pole pairs each having a width 2λ and
each being formed of a first magnetic portion having a width λ and
a second magnetic portion having the width λ
, which have different magnetic properties, are arranged at equal pitches of a period of the magnetic pole pair width 2λ
;a magnetosensitive device arranged so as to be opposed to the magnetized scale with a predetermined air gap therebetween, the magnetosensitive device being configured to move relatively in a direction of arrangement of the magnetized scale within a magnetic field formed by the magnetized scale while maintaining the air gap, and to measure a change of the magnetic field due to the relative movement with use of magnetosensitive elements; and a position calculation circuit configured to analyze an output value of the magnetosensitive device, to thereby calculate a relative position between the magnetosensitive device and the magnetized scale, wherein the magnetosensitive device comprises, as the magnetosensitive elements, a first magnetosensitive element group in which n first magnetosensitive elements, where n is a natural number of 2 or more, are arranged at equal magnetosensitive element pitches P so that λ
=nP is established, and the n first magnetosensitive elements of the first magnetosensitive element group are configured to output results of measuring the change of the magnetic field due to the relative movement in parallel, andwherein the position calculation circuit analyzes output values that are output from the magnetosensitive device in parallel, to thereby calculate the relative position between the magnetosensitive device and the magnetized scale as a position detection resolution of λ
/n. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A magnetic position detection method to be used for a magnetic position detection device,
the magnetic position detection device comprising: -
a magnetized scale in which magnetic pole pairs each having a width 2λ and
each being formed of a first magnetic portion having a width λ and
a second magnetic portion having the width λ
, which have different magnetic properties, are arranged at equal pitches of a period of the magnetic pole pair width 2λ
;a magnetosensitive device arranged so as to be opposed to the magnetized scale with a predetermined air gap therebetween, the magnetosensitive device being configured to move relatively in a direction of arrangement of the magnetized scale within a magnetic field formed by the magnetized scale while maintaining the air gap, and to measure a change of the magnetic field due to the relative movement with use of magnetosensitive elements; and a position calculation circuit configured to analyze an output value of the magnetosensitive device, to thereby calculate a relative position between the magnetosensitive device and the magnetized scale, the magnetosensitive device comprising, as the magnetosensitive elements, a first magnetosensitive element group in which n first magnetosensitive elements, where n is a natural number of 2 or more, are arranged at equal magnetosensitive element pitches P so that λ
=nP is established, the n first magnetosensitive elements of the first magnetosensitive element group being configured to output results of measuring the change of the magnetic field due to the relative movement in parallel,the magnetic position detection method comprising; a Hi/Lo determination step of making, by the position calculation circuit, a Hi/Lo determination on each of the n output values output from the magnetosensitive device in parallel to obtain binary values, and outputting the obtained binary values as n Hi/Lo outputs; a storing step of storing, by the position calculation circuit, a position calculation table in a storage unit, in which a relationship between 2n internal magnetic pole positions M, where M represents 2n integers of 0 or more and 2n−
1 or less, which are the relative positions within the magnetic pole pair width 2λ
, and a pattern of the n Hi/Lo outputs is defined in advance; andan internal magnetic pole position calculation step of calculating, by the position calculation circuit, based on the position calculation table stored in the storage unit in the storing step, the internal magnetic pole position M of the magnetosensitive device corresponding to the n Hi/Lo outputs as a position detection resolution of λ
/n.
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Specification