JPS63136046U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram of a brake device according to this invention, and FIG. 2 is a hydraulic circuit diagram of a conventional technique. 8... Swivel motor, 9L, 9R... Left and right travel valve, 10, 11, 12... ATT switching valve, 13...
...Swivel valve, 14...Remote control valve for ATT, 15...
...Remote control valve for turning, 16...Brake mechanism, 1
7... Open/close valve, 18... Direct travel valve, 19,57
...Pilot switching valve.

Claims (1)

[Scope of utility model registration request] The various hydraulic actuators installed on construction machinery are divided into two groups A and B, and the left and right traveling valves are installed in the front row of each group, and all the switching valves for other actuators are arranged in parallel. 1. A straight travel valve is provided in the oil passage on the second pump discharge side, and an on-off valve is provided in parallel with the left travel motor in the oil passage that communicates the left travel motor and the left travel valve, and the on-off valve is connected to the left and right travel motor. When stopped, the pilot oil passage leading from the pilot pump is shut off, and when the left and right travel motors are in operation, the pilot oil passage is opened, so that the pilot pressure from the pilot pump can be applied to the pilot pressure receiving part of the straight travel valve. In the first case, when both the left and right traveling valves are in neutral or only the left and right traveling valves are in the simultaneous operating position, the oil passage from the first pump is shut off and the oil passage from the second pump is opened. In the second case where the valve and any other actuator switching valve are in an operating position other than the neutral position, the oil passages from the first and second pumps can be switched to the parallel open oil passage position, and the upper rotation In an upper swing type construction machine equipped with a swing parking brake mechanism in which the brake is applied to the swing axis of the body and the brake is released by hydraulic pressure, the hydraulic pressure acting part of the brake mechanism and the pilot pump are connected to each other. A pilot switching valve having two pilot pressure receiving sections on either the left or right side is provided in the middle of the communicating oil passage, and one of the two pilot pressure receiving sections is used to switch the pilot of the straight-ahead valve. It communicates with the pressure receiving part and the shuttle valve of the swing remote control valve, and also connects the pressure oil supply side of the work attachment switching valve on the most upstream side of groups A and B, respectively, via the shuttle valve, and connects the pilot A brake device for parking a revolving structure of a construction machine, characterized in that the other pilot pressure receiving part of the switching valve is configured to communicate with the working attachment pressure oil supply side shuttle valve.