Patent ID: 7458867

Claim:
A vertical fluid power transmission comprising: a crankshaft of an engine, the crankshaft having an axis in a vertical direction; an output shaft having an axis in a vertical direction; a torque converter which has an axis in a vertical direction, and is disposed between the crankshaft and the output shaft; the torque converter including: a pump impeller connected to the crankshaft; a turbine runner connected to the output shaft so as to be opposed to the pump impeller; a stator arranged between the pump impeller and the turbine runner; and a circulation circuit of a power transmission oil, the circuit being defined between the pump impeller, turbine runner and stator, wherein an oil supply passage is connected to one end of the circulation circuit, and guides a stored oil that is drawn up from an oil tank and discharged by an oil pump, wherein an oil return passage is connected to the other one end of the circulation circuit, and leads to the oil tank, and wherein a normally-closed pressure response valve is provided in the oil return passage, the pressure response valve being opened when an upstream pressure reaches a predetermined value.