Magnetic rotary encoder for detection of incremental angular displacement
US4319188A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 1980 |
| Grant date | Mar 9, 1982 |
| Priority date | — |
| Expiry date | Dec 24, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetic rotary encoder for detecting incremental angular displacement, angular velocity and rotating direction using magneto-resistors is disclosed. A drum, disk or cupshaped rotary member is attachable to a rotatable shaft. A magnetic medium is provided on a surface of the rotary member and is divided at a pitch p into a plurality of magnetic sections each of which has a magnetic signal recorded. The magnetic medium produces an alternating magnetic field as the rotary member revolves. Alternatively, a plurality of permanent magnets are provided on the surface of the rotary member to produce the alternating magnetic field of the rotary member revolves. A magnetic field detector includes at least one magneto-resistor having a stripe-like configuration with width D. The magneto-resistor is located in the vicinity of the rotary member so as to be spaced from the magnetic medium or the permanent magnets by equal to or less than p at its nearest portion and by equal to or less than 20p at its furthest portion. The width D is selected so as not to be in excess of 20p but to be equal or less than p .sec .phi., where .phi. is an angle defined by the nearest surfaces of the magneto-resis…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.