US4851771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic encoder for detection of incremental and absolute value displacement
Assignee: Yaskawa Electric Corp
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Filing: 1988-02-24
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Granted: 1989-07-25
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Expires: 2008-02-24
Abstract
Abstract A magnetic encoder for detecting the speed of an actuator adapted to carry out rotational movement or linear movement by a magneto-resistor is disclosed. This magnetic encoder is intended to carry out output conversion by using a stripe-shaped magneto-resistor located close to a magnetic medium with respect to a periodic magnetic field coming out of the magnetic medium on which at least one track of magnetization patterns are recorded by a pitch p in order to generate the periodic magnetic field depending on the required position reading accuracy. When the unit stripe length of the magneto-resistor is represented by l and the closest distance between the magnetic medium and the magneto-resistor is represented by g, the angle α defined between the longitudinal direction of the stripe and the surface of the magnetic medium located at the closest part ranges from ##EQU1## to 90 degrees and the lateral direction of the stripe is oriented parallel to the direction of the magnetic field from the magnetization patterns.
Inventors
- 👤 Michiaki Ikeda
- 👤 Hisayuki Kaku
- 👤 Shinji Yamashita
- 👤 Kenji Hara
- 👤 Hiroyuki Ono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:52
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/142; G01D5/145; G01D5/244; G01D5/249; G01D5/2497; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/481; G01P3/487
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
162 words
A magnetic encoder adapted to carry out output conversion , comprising: a stripe shaped magneto-resistor; a magnetic medium movable in a predetermined direction and located close to said magneto-resistor, said magnetic medium having at least one track of magnetization patterns recorded by a pitch p so as to generate a periodic magnetic field depending on the required position reading accuracy, said magnetic field coming out of said magnetic medium and having a direction perpendicular to the predetermined direction in which the magnetic medium is movable, wherein when a unit stripe length of said magneto-resistor is represented by l and the closest distance between the magnetic medium and the magneto-resistor is represented by g, the angle α defined between the longitudinal direction of the stripe and the surface of the magnetic medium located at the nearest part ranges from ##EQU11## to 90 degrees and the lateral direction of the stripe is oriented parallel to the direction of magnetic field from said magnetization patterns.
Claim 2
Dependent Claim
162 words
A magnetic encoder adapted to carry out output conversion , comprising: a stripe shaped magneto-resistor; a magnetic medium movable in a predetermined direction and located close to said magneto-resistor, said magnetic medium having at least one track of magnetization patterns recorded by a pitch p so as to generate a periodic magnetic field depending on the required position reading accuracy, said magnetic field coming out of said magnetic medium and having a direction perpendicular to the predetermined direction in which the magnetic medium is movable, wherein when a unit stripe length of said magneto-resistor is represented by l and the closest distance between the magnetic medium and the magneto-resistor is represented by g, the angle α defined between the longitudinal direction of the stripe and the surface of the magnetic medium located at the nearest part ranges from ##EQU11## to 90 degrees and the lateral direction of the stripe is oriented parallel to the direction of magnetic field from said magnetization patterns.
Claim 3
Dependent Claim
24 words
The magnetic encoder of claim 1, wherein the intensity of magnetization of the magnetic medium continuously varies within the range of a single pitch.
Claim 4
Dependent Claim
28 words
The magnetic encoder of claim 2, wherein the intensity distribution of magnetization of the magnetic medium within the range of a single pitch exhibits a sine wave shape.
Claim 5
Dependent Claim
29 words
The magnetic encoder of claim 2, wherein the intensity distribution of magnetization of the magnetic recording medium within the range of a single pitch exhibits a triangular wave shape.
Claim 6
Dependent Claim
30 words
The magnetic encoder of any one of claims 2 to 4 wherein within a single magnetization pattern track on the magnetic medium, adjacent patterns are magnetized in the same direction.
Claim 7
Dependent Claim
30 words
The magnetic encoder of any one of claims 2 to 4, wherein within a single magnetization pattern track on the magnetic recording medium, adjacent patterns are magnetized in opposite directions.
Claim 8
Dependent Claim
90 words
The absolute type magnetic encoder of claim 1, wherein the magnetization patterns existing within a single pitch comprise magnetized portions and nonmagnetized portions, at least two tracks of magnetization pattern are provided, the magneto-resistor is arranged corresponding to each of said magnetization pattern tracks so as to detect a magnetic field leaking from each of the magnetization pattern track, and the absolute position of a substrate on which the magnetic medium is placed is read out with the aid of a combination of the magnetization pattern track with the magneto-resistor.
Claim 9
Dependent Claim
41 words
The absolute type magnetic encoder of claim 7, wherein within a single magnetization pattern track, the direction of magnetization of a magnetized portion is opposed to the direction of magnetization of an adjacent magnetized portion with a nonmagnetized portion interposed therebetween.
Claim 10
Dependent Claim
42 words
The absolute type magnetic encoder of claim 7, wherein within a single magnetization pattern track, the direction of magnetization of a magnetized portion is oriented in the same direction as that of an adjacent magnetized portion with a non-magnetized portion interposed therebetween.
Claim 11
Dependent Claim
86 words
The absolute type magnetic encoder of any one of claims 2 to 4, wherein at least two tracks of magnetization pattern are provided, the magneto-resistor is arranged corresponding to each of said magnetization pattern track so as to detect a magnetic field leaking from each of the magnetization patterns, said angle is about 90 degrees, and the absolute position of a substrate on which the magnetic medium is placed is read out with the aid of a combination of the magnetization pattern track with the magneto-resistor.
References Cited (Backward Citations)
US4319188A
Cited
US4274053A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-24 | 1993-01-23 | 1993-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-24 | 1997-01-23 | 1997-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-24 | 2001-01-23 | 2001-07-25 | $7700.00 | Window Closed / Lapsed |