Controller and control method of electric pump feedback controlled as a function of drain flow rate for a continuously variable transmission

摘要

When the pressure of a discharge fluid of an electric pump (1) exceeds a predetermined relief pressure, relief valve (6) discharges a part of the fluid to a drain passage (5). A sensor (8, 10, 11) detects a drain flowrate of the drain passage (5), and feedback control of the rotation speed of the electric pump (1) is performed so that the drain flowrate coincides with a predetermined flowrate. Due to this feedback control, the necessary fluid pressure is maintained while suppressing the drain flowrate to the minimum.