Heat protected position transducer in an electric motor
US5998783A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 14, 1997 |
| Grant date | Dec 7, 1999 |
| Priority date | — |
| Expiry date | Jan 14, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/3473
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An encoder disc (101) of an optical position transducer is mounted on a short protruding part (102a) of a rotor (102) of an electric motor close to torque creating parts. One part of the optical system, normally the light emitter part (108, 115), is insertable between the rotor (102) and the encoder disc (108) after the insertion of the rotor-encoder disc assembly into the motor stator case (113). The optical incremental encoder signals are fed both to a moderate frequency digital counter that counts (4) counts per basic encoder period and to an AD converter that samples and digitises the primary encoder analog signals. A synchronising network ensures that the primary encoder digitised signal corresponds to the correct state of the digital counter. More than one decoder head can be used to compensate for the bearing play common in servo motors having varying axial loads. This construction gives a high speed resolution and fast speed response, is very compact and operates with modest demands on bearing precision.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.