Hydraulically operated continuously variable transmission.

摘要

A hydraulically operated continuously variable transmission includes a hydraulic pump (P) coupled to an input shaft (2), a hydraulic rotor (M) coupled to an output shaft (11), a closed hydraulic circuit (CVT) interconnecting the hydraulic pump and the hydraulic motor, and a control valve(170) coupled to an inlet of the hydraulic pump and openable for discharging working oil from the hydraulic pump when the pressure of oil in the inlet of the hydraulic pump is below a prescribed pressure level. The transmission also includes a hydraulically hermetic chamber defined between the pump and motor cylinders and accommodating therein the pump swash plate (32) and the pump plungers (6), and oil discharge means disposed in the motor cylinder for discharging oil from the hydraulically hermetic chamber when the pressure of oil in the hydraulically hermetic chamber is below a prescribed pressure level.