Hydraulic circuit for controlling a motor-pump set, uses valve device for switching pump for outlet when speed of motor is less than given revs rate

摘要

A hydraulic circuit for controlling a motor-pump set has a pair of axially parallel pinions (41,42), a pimp body (45) with inner chamber (46), and an outlet which establishes the forward supply or advance (32) of the pump. A first axial channel (48a) and a second axial channel (48b) communicate with the forward supply (32) and the suction (31), and a valve device (20) communicates with the second axial channel (48b) by its inlet and by its outlet with the first axial channel (48a). The valve device is designed so that it switches the pump for outlet when the speed of the motor is less than a predetermined revs rate (N), so that the developed torque is sufficiently high to overcome the starting torque and to close the outlet when the given motor revs are reached or exceeded.