Rotation angle sensor and method for determining the absolute angular position of a body undergoes several rotations

US7637020B2 · kind B2 · utility

Assignee

• Leopold KOSTAL GmbH & Co. KG · DE

Inventors

• Oliver Maier · Worms, DE
• Christian Schirp · Bochum, DE

Key dates

• Filing date: Feb 28, 2008
• Grant date: Dec 29, 2009
• Expiry date: Jul 18, 2028

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/145
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A sensor determines the absolute angular position of a body that can rotate through rotations. The sensor includes two code wheels which rotate as the body rotates. The code wheels are driven at a different gear ratio such that the code wheels rotate faster than the body and the code wheels rotate at different rates. Two sensor elements respectively determine the rotational angle positions of the code wheels. The difference between the rotational angle positions is a beat angle. The different gear ratio is selected such that beat angle periods are in an angular measuring range of the sensor and the absolute angular positions of the code wheels in the beat angle periods is different. The absolute angular positions of the code wheels in successive beat angle periods is offset by the nth part of the measuring range of a sensor element, where n is number of beat angle periods.