Inductive position measuring device or goniometer

US7719263B2 · kind B2 · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventors

• Markus Eissner · Eschenbach, DE
• Michael Schreiber · Frankfurt, DE
• Josef Habenschaden · Dessau, DE

Key dates

• Filing date: Nov 20, 2007
• Grant date: May 18, 2010
• Expiry date: Nov 20, 2027

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/202
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to an inductive position measuring device or goniometer having two to no more than five digital oscillators, each of which contains measuring coils or reference coils. Particularly favorable for one application as a transmission sensor is a coil array for three or four oscillators that includes two measuring coils and/or two reference coils. When one plate-shaped measuring element that is sensitive for eddy currents passes through the measuring area, a measuring coil arranged in a planar manner is increasingly covered. One reference coil is arranged such that it does not touch the movement track of the measuring element, but is exposed to the same ambient conditions (temperatures) as the measuring coil. Another reference coil is arranged such that it is covered by the measuring element in the entire measuring area and therefore can compensate the fluctuations in the spacing height between the planar coil array and the measuring element that occur during operation. It is also possible to use additional height reference coils to compensate tilting of the measuring element. Pulse frequencies of the digital oscillator signals are counted asynchronously and subtrac…