The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 19, 1991
Filed:
Apr. 27, 1987
Dennis W Smith, Phoenix, AZ (US);
Honeywell Inc., Minneapolis, MN (US);
Abstract
A lubricating film thickness measuring system and method includes a rolling element bearing having a relatively rotatable electrically insulated inner and outer races forming a raceway therebetween. Rolling elements are movably mounted in the raceway. Apparatus is provided for measuring capacitance across the bearing. The measuring apparatus includes an oscillator circuit and a phase detection circuit and is responsive to a phase angle shift between a first signal going from an oscillator circuit to the bearing and from the bearing to the phase detection circuit, and a second signal received by the phase detection circuit directly from the oscillator circuit. The method involves applying a predetermined electrical signal across the rolling elements and measuring the capacitance across the rolling elements thereby providing a measure of the lubricating film thickness.