PURPOSE: To prevent the rotation of an engine being stopped by providing an opening and closing valve and a check valve to a circuit in such a way that no influence of the oil pressure of a pump in operation exerts on the pump being stopped of plural oil-pressure pumps.
CONSTITUTION: When an engine 11a turns and an engine 11b is stopped, a swirl pump 16a and a pilot pump 15a are actuated, and their discharge pressures are supplied through a check valve 28a to a pilot valve 23. Also, under the condition that an valve 26a is in opened state, the discharge pressure of the pump 15a is supplied as a servo pressure to the regulator 22a. By this, the swirl pump 10 is turned through the regulator 22a and the pump 16a by operation of a lever 24. On the other hand, since the pilot pump 15 does not discharge oil and the discharge pressure of the pilot pump 15a is interrupted by the check valve 28b, the valve 26b is inclosed state, a servo pressure circuit 25b is connected with a tank 27b, and the circuit pressure is zeroed.
TANAKA SOUTAROU
YAGIYUU TAKASHI
SAKAKI YASUO
IZUMI EIKI
