Fluid Pump: Description and Operation

DESCRIPTION
The oil pump provides a supply of fluid (oil) under pressure to operate, lubricate, and cool the Transaxle. The oil pump is a variable capacity vane and rotor pump with output flow proportional to demand. The oil pump is mounted to the Transaxle case.

OPERATION
^ The outer rotor, inner rotor, and oil pump flange are installed within the oil pump housing. The oil pump flange and oil pump shaft are coupled to the inner rotor. The other end of the oil pump shaft is coupled to the pump impeller side of the torque converter, and by way of the converter. As a result, the oil pump flange, the inner rotor, and the outer rotor rotate as one with the engine.
^ A pressure regulator valve and spring, installed in the discharge section of the pump housing, regulates the oil discharge amount. When the speed of the engine is low, the amount of oil discharged increases in proportion to engine rpm. When the engine rpm increases and the Transaxle fluid pressure becomes greater, the pressure regulator valve is pressed against the spring and compresses it as it moves to the right. The oil is redirected through port A to port B and circulates back to the inlet side of the pump, with the result that the amount of oil discharged is fixed.