Magnetic position detection device and magnetic position detection method
First Claim
1. A magnetic position detection device, comprising:
- a magnetic encoder comprising N-magnetic poles and S-magnetic poles alternately arranged in a moving direction; and
a magnetosensitive portion configured to detect a change in a magnetic field along with movement of the magnetic encoder so as to detect a position of the movement of the magnetic encoder, wherein;
the magnetosensitive portion comprises direction detection type magnetoresistive elements, each of the direction detection type magnetosensitive elements having a resistance value that changes in accordance with on a direction of the magnetic field;
when a magnetic-field component in the moving direction of the magnetic encoder and a magnetic-field component in a direction in which the magnetosensitive portion and the magnetic encoder are opposed to each other, which are formed at a position of the magnetosensitive portion, are Bs and Br, respectively, the magnetic encoder further comprises non-magnetized portions that are unmagnetized and are arranged at boundaries between the N-magnetic poles and the S-magnetic poles so that changes in the magnetic-field component Bs and the magnetic-field component Br through the movement of the magnetic encoder are approximately sinusoidal; and
a length of each of the non-magnetized portions in the moving direction is shorter than a length of each of the N-magnetic poles and the S-magnetic poles in the moving direction,wherein, when a pitch of a magnetic-pole pair including a pair of the N-magnetic pole and the S-magnetic pole, the non-magnetized portion between the N-magnetic pole and the S-magnetic pole, and the non-magnetized portion present on a side of the N-magnetic pole or the S-magnetic pole, which is opposite to the non-magnetized portion, is λ
, the length of each of the non-magnetized portions in the moving direction is approximately λ
/6.
1 Assignment
0 Petitions
Accused Products
Abstract
A magnetic position detection device configured to detect a relative movement position of a magnetic encoder, which includes N-magnetic poles and S-magnetic poles arranged alternately in a moving direction, by a magnetosensitive portion as a change in direction of a magnetic field from the encoder. As the magnetosensitive portion, direction detection type magnetoresistive elements are arranged, which each have a resistance value that changes depending on a direction of an applied magnetic field. The encoder further includes non-magnetized portions arranged at boundaries between the N-magnetic poles and the S-magnetic poles so that changes through the movement of the encoder of a magnetic-field component Bs in the moving direction of the encoder and a magnetic-field component Br in a direction in which the magnetosensitive portion and the encoder are opposed to each other, which are formed at a position of the magnetosensitive portion, are approximately sinusoidal.
12 Citations
12 Claims
-
1. A magnetic position detection device, comprising:
-
a magnetic encoder comprising N-magnetic poles and S-magnetic poles alternately arranged in a moving direction; and a magnetosensitive portion configured to detect a change in a magnetic field along with movement of the magnetic encoder so as to detect a position of the movement of the magnetic encoder, wherein; the magnetosensitive portion comprises direction detection type magnetoresistive elements, each of the direction detection type magnetosensitive elements having a resistance value that changes in accordance with on a direction of the magnetic field; when a magnetic-field component in the moving direction of the magnetic encoder and a magnetic-field component in a direction in which the magnetosensitive portion and the magnetic encoder are opposed to each other, which are formed at a position of the magnetosensitive portion, are Bs and Br, respectively, the magnetic encoder further comprises non-magnetized portions that are unmagnetized and are arranged at boundaries between the N-magnetic poles and the S-magnetic poles so that changes in the magnetic-field component Bs and the magnetic-field component Br through the movement of the magnetic encoder are approximately sinusoidal; and a length of each of the non-magnetized portions in the moving direction is shorter than a length of each of the N-magnetic poles and the S-magnetic poles in the moving direction, wherein, when a pitch of a magnetic-pole pair including a pair of the N-magnetic pole and the S-magnetic pole, the non-magnetized portion between the N-magnetic pole and the S-magnetic pole, and the non-magnetized portion present on a side of the N-magnetic pole or the S-magnetic pole, which is opposite to the non-magnetized portion, is λ
, the length of each of the non-magnetized portions in the moving direction is approximately λ
/6. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A magnetic position detection device, comprising:
-
a magnetic encoder comprising N-magnetic poles and S-magnetic poles alternately arranged in a moving direction; and a magnetosensitive portion configured to detect a change in a magnetic field along with movement of the magnetic encoder so as to detect a position of the movement of the magnetic encoder, wherein; the magnetosensitive portion comprises direction detection type magnetoresistive elements, each of the direction detection type magnetosensitive elements having a resistance value that changes in accordance with on a direction of the magnetic field; when a magnetic-field component in the moving direction of the magnetic encoder and a magnetic-field component in a direction in which the magnetosensitive portion and the magnetic encoder are opposed to each other, which are formed at a position of the magnetosensitive portion, are Bs and Br, respectively, the magnetic encoder further comprises non-magnetized portions that are unmagnetized and are arranged at boundaries between the N-magnetic poles and the S-magnetic poles so that changes in the magnetic-field component Bs and the magnetic-field component Br through the movement of the magnetic encoder are approximately sinusoidal; and when a pitch of a magnetic-pole pair including a pair of the N-magnetic pole and the S-magnetic pole, the non-magnetized portion between the N-magnetic pole and the S-magnetic pole, and the non-magnetized portion present on a side of the N-magnetic pole or the S-magnetic pole, which is opposite to the non-magnetized portion, is λ
, a length of each of the non-magnetized portions in the moving direction is approximately λ
/6. - View Dependent Claims (11)
-
-
12. A magnetic position detection method for detecting a relative movement position of a magnetic encoder, which includes N-magnetic poles and S-magnetic poles arranged alternately in a moving direction, by a magnetosensitive portion as a change in a magnetic field from the magnetic encoder, the magnetic position detection method comprising:
-
arranging, as the magnetosensitive portion, direction detection type magnetoresistive elements, each of the direction detection type magnetosensitive elements having a resistance value that changes in accordance with on a direction of the magnetic field; and arranging, when a magnetic-field component in the moving direction of the magnetic encoder and a magnetic-field component in a direction in which the magnetosensitive portion and the magnetic encoder are opposed to each other, which are formed at a position of the magnetosensitive portion, are Bs are Br, respectively, non-magnetized portions that are unmagnetized in the magnetic encoder at boundaries between the N-magnetic poles and the S-magnetic poles so that changes in the magnetic-field component Bs and the magnetic-field component Br through the movement of the magnetic encoder are approximately sinusoidal, wherein a length of each of the non-magnetized portions in the moving direction is approximately λ
/6, and λ
is a pitch between two adjacent N-magnetic poles among the N-magnetic poles.
-
Specification