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:
Jun. 30, 1987
Filed:
Apr. 21, 1986
Fichtel & Sachs AG, Schweinfurt, DE;
Abstract
The fluid friction clutch comprises a clutch input part drivable about a rotation axis and a clutch output part rotatable coaxially in relation to the clutch input part. The clutch output part together with the clutch input part defines at least one shear gap. A cover which forms a cavity enclosing at least the region of the shear gap is filled partially with viscous fluid and otherwise with gas. The gas-filled volume of the cavity contains less than 18 percent of oxygen by volume, preferably not more than 5 percent of oxygen by volume, in order to preclude a chemical reaction of the viscous fluid with the oxygen under thermal overloading which limits the utility of the viscous fluid. To reduce the proportion of oxygen either the cavity is evacuated or it is filled with a substantially oxygen-free protective or noble gas.