PARKING BRAKE CIRCUIT OF HYDRAULICALLY DRIVEN VEHICLE.

摘要

A parking brake circuit for a hydraulically driven vehicle which prevents the occurrence of an erroneous operation at the time of driving on the downward slope. The circuit comprises first and second main circuits (2, 3) for supplying a hydraulic oil to a hydraulic motor (1) for driving, a counterbalance valve (4) disposed between these main circuits and passing the hydraulic oil on the high pressure side to a pressure reception chamber (6a) of an actuator (6) for actuating a parking brake, a conduit line (5) for connecting the output port of the counterbalance valve to the pressure reception chamber and a slow return valve (12) disposed in the conduit line in such a manner as to regulate the flow of the hydraulic oil flowing from the pressure reception chamber to the counterbalance valve.