Viscous fluid coupling device

摘要

A viscous fluid coupling device is comprised of a drive rotor having axially extending annular projections on opposite surfaces thereof, a casing surrounding said rotor and having axially extending annular projections interposed between the annular projections on one side of said rotor, a separator disc secured within said casing to divide the interior of said casing into a reservoir chamber and a working chamber, said disc having axially extending annular projections interposed with the annular projections on the other surface of said rotor and having first and second openings angularly offset from each other at different radial distances, a valve strip slidably engaging said disc for controlling the opening and closing of the openings under the control of a temperature responsive bimetallic coil. The valve strip will open the radially outer opening at a first temperature and subsequently open the radially inward opening at a second temperature greater than the first temperature to sequentially provide a viscous fluid to the two sets of interposed annular projections for driving a fan secured to the housing at two different speeds.