Temperature responsive, pneumatically actuated, fluid shear, cooling fan clutch and control therefor

摘要

A cooling fan device for use with an internal combustion engine in which there is provided a viscous fluid coupling. A viscous fluid valve is operable to control the opening of a hole so as to regulate the flow of fluid from a working chamber to a reservoir chamber. The valve which is operated in response to the change in the temperature of the engine cooling water, is secured to a slidable plug which is surrounded by a diaphragm. A changover valve controls the admission of suction air (vacuum) or atmospheric air in response to the change in engine pressure.