Hydraulic motor drive for engine cooling fan - has valve which increases pressure on motor gears with increasing speed

摘要

The cooling fan of an IC engine is driven by a hydraulic motor (14) which is supplied with oil from a pump (10). The hydraulic motor (14) is of the gear tooth type and has a pressure plate (46) pressed against one side of the pair of gears. The pressure (Ps) exerted on the pressure plate (46) is due to oil supplied through a throttling orifice (19) from the pump (10). The oil supply pipe (16) is connected to a valve (17) which is normally held open by a spring (25). As the engine speed increases the oil pressure in the pipe (16) increases and overcomes the spring pressure and closes the valve (17). The pressure on the pressure plate (46) is then increased so that it equals the delivery pressure of the pump (10). USE - Hydrostatic drive for engine cooling fan.