Fluid friction clutch

US4676355A · kind A · utility

Assignee

• Fichtel & Sachs · DE

Inventors

• Gerd Brunken · Dittelbrunn, DE
• Werner Gob · Kürnach, DE
• Dieter Neugebauer · Schweinfurt, DE

Key dates

• Filing date: Apr 21, 1986
• Grant date: Jun 30, 1987
• Expiry date: Apr 21, 2006

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16D35/026
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

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.