Hydrodynamic control coupling

Abstract

The disclosure concerns a hydrodynamic control coupling with a primary drive vane wheel and a secondary driven vane wheel which together define a toroidal working chamber. Each vane wheel carries an array of vanes on its interior which extend toward the vanes of the other vane wheel. The vanes of the vane wheels are inclinded with respect to the axis of the coupling, yet each is oriented parallel to a respective radius of the coupling. Furthermore, the vanes on each of the vane wheels are inclined to extend toward the vanes on the other wheel. There is a working fluid inlet to the working chamber. A working fluid outlet from the working chamber is through the secondary, driven vane wheel and is via a plurality of bores extending tangentially toward the axis of the coupling. An overflow valve communicates with the outlet from the working chamber. Upon the rotary speed of the primary vane wheel increasing rapidly, the overflow valve reacts by opening more widely, reducing the filling level in the coupling. A temperature sensor may be connected with the overflow valve for operating the overflow valve so it is dependent upon the temperature sensed by the sensor. The temperature sensor may be in the engine cooling circuit of an engine, and the coupling may drive a cooling fan for that circuit. The valve will control the torque of the coupling for desired cooling rotation of the fan, depending upon the sensed temperature of the engine cooling circuit.