Rotary actuator
US4491815A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Apr 22, 1983 |
| Grant date | Jan 1, 1985 |
| Priority date | — |
| Expiry date | Apr 22, 2003 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M2003/067
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A rotary actuator for driving a fluid control valve comprises a yoke which forms a closed magnetic path an excitation coil which produces a magnetic flux in the yoke, a permanent magnet which is rotatably arranged in a through hole or in a slit formed in the yoke, and a restoring spring which produces a force acting against a rotational torque generated in the magnet by a main magnetic flux which flows through the yoke and the permanent magnet when the excitation coils is energized. Shielding portions are formed on both sides of the ends of the yoke, which ends oppose the permanent magnet, so as to substantially shield the permanent magnet together with the ends of the yoke, whereby a magnetic reluctance of a path of the magnetic flux remains substantially constant irrespective of the rotating position of the permanent magnet with respect to the yoke when the excitation coil is de-energized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.