JPS6391547U

JPS6391547U -

Info

Publication number: JPS6391547U
Application number: JP18334186U
Authority: JP
Priority date: 1986-11-27
Filing date: 1986-11-27
Publication date: 1988-06-14

Description

[Brief explanation of the drawing]

第１図および第２図は本考案の油圧回路図、第
３図は従来技術の油圧回路図である。１Ｌ，１Ｒ……左右走行モータ、５……アーム
シリンダ、６，８……第１、第２ポンプ、１１Ｌ
，１１Ｒ……左右走行弁、１５……アーム弁、１
６……走行直進弁、２５……リモコン弁、４４…
…絞り部、４６……パイロツト開閉弁、４８Ｌ，
４８Ｒ……昇圧型リリーフ弁。 1 and 2 are hydraulic circuit diagrams of the present invention, and FIG. 3 is a hydraulic circuit diagram of the prior art. 1L, 1R...Left and right travel motor, 5...Arm cylinder, 6, 8...1st, 2nd pump, 11L
, 11R...Left and right travel valve, 15...Arm valve, 1
6... Straight travel valve, 25... Remote control valve, 44...
... Throttle part, 46... Pilot on-off valve, 48L,
48R...Boost type relief valve.

Claims

[Scope of utility model registration request]

The various hydraulic actuators installed in the hydraulic excavator are divided into two groups A and B, the left and right traveling valves are provided in the front row of each group, and all other actuator switching valves are arranged in parallel with this,
In addition, a foot relief valve and a throttle part are connected in parallel to the outlet sides of the center bypass oil passages passing through the switching valves in groups A and B, respectively, and the upstream side thereof is connected to the outlet side of the center bypass oil passage.
, each of the second pumps is connected to the regulator, and its downstream side is communicated with the oil tank, and a straight-travel valve is provided in the oil passage on the discharge side of the first and second pumps, while,
An on-off valve is provided in parallel with the left-hand drive motor in the oil path that communicates the left-hand drive motor and the left-hand drive valve, and the on-off valve is used to shut off the pilot oil path from the remote control valve when the left-right drive motor is stopped, and to shut off the pilot oil path from the remote control valve when the left-right drive motor is activated. By opening the oil passage, the pilot pressure for the remote control from the pilot pump can be applied to the pilot pressure receiving part of the straight travel valve, and the left and right travel valves are both neutral or only the right and left travel valves are in the first position where they are simultaneously operated. In this case, the oil passage from the first pump is shut off, and the oil passage from the second pump is opened. In this case, the oil passages from the first and second pumps can be switched to a parallel open oil passage position, and in the second case, the downstream side oil passage of the traveling straight valve communicating from the first pump and the second pump discharge at the time of switching. In a hydraulic circuit in which a throttle part is arranged in the middle of the oil passage communicating with the side oil passage, groups A and B
A boost type relief valve is interposed between the pressure oil supply oil passage of the switching valve for the work attachment inside and the regulators for the first and second pumps, while a pilot opening/closing valve is provided on the upstream side or downstream side of the throttle part. In addition to providing a valve, the pilot pressure outlet oil passage of one or more specific remote control valves other than the traveling valve is configured to communicate with the pilot pressure receiving portion of each boost type relief valve and pilot opening/closing valve. Hydraulic excavator hydraulic circuit.