JPH0452603U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram of a backhoe working vehicle showing an example of the hydraulic circuit of the present invention, FIG. 2 is a side view of the backhoe working vehicle, and FIG. 3 is a view taken along the - arrow in FIG. 2. In the figure, 8 is a boom hoisting cylinder (actuator), 9 is an arm hoisting cylinder (actuator), 10 is a bucket rotation cylinder (actuator), 13 is a first traveling motor (actuator), and 14 is a second traveling motor. Motor (actuator), 17 is a turning motor (actuator)
, 23 is a first pump, 24 is a first pressure oil supply pipe, 2
5 is a first travel operation valve (operation valve), 26 is a boom operation valve (operation valve), 27 is a bucket operation valve (operation valve), 29 is a second pump, 30 is a second pressure oil supply pipe,
31 is a second travel operation valve (operation valve), 32 is an arm operation valve (operation valve), 38 is a tank, 42, 43,
44, 45, 46, 47, 75, 76 are pilot ports, 58 is a third pump, 59 is a third pressure oil supply pipe, 60 is a swing operation valve (operation valve), and 63 is a first
Communication valve 64 indicates a second communication valve.

Claims (1)

[Scope of utility model registration request] First pressure oil supply pipe 24 communicating with first pump 23
In addition, a plurality of operating valves 25, 26, 27 including pilot pressure switching type operating valves 26, 27 are connected in tandem from the upstream side to the downstream side, and actuators 13, 8, 27 are connected to each operating valve 25, 26, 27.
10, and furthermore, the downstream end of the first pressure oil supply pipe 24 is connected to the tank 38, and the second pump 2
A plurality of operating valves 31 including a pilot pressure switching type operating valve 32 are connected to the second pressure oil supply pipe 30 communicating with the
, 32 are connected in tandem from the upstream side to the downstream side, and the actuators 14 and 9 are connected to each operation valve 31 and 32, and a third pressure oil supply pipe 59 communicating with the third pump 58 is further connected with a second pressure. The downstream end of the oil supply pipe 30 is communicated with the tank 38, and the operation valve 60, the first communication valve 63, and the second communication valve 64 are connected in tandem from the upstream side to the downstream side,
Connect the actuator 17 to the operation valve 60,
A portion of the third pressure oil supply pipe 59 downstream of the second communication valve 64 is connected to the upstream side of each operation valve 26 , 27 , 32 in the hydraulic oil supply direction, and the operation valve 25
, 31 on the downstream side in the hydraulic oil supply direction.
Connect the pilot port 75 of the operating valve 25.
, 31 is switched to the hydraulic oil supply position, the first communication valve 63 is switched to the communication position by the hydraulic oil discharged by the first pump 23 or the second pump 29, and the third pressure oil supply pipe 59 1st of
The upstream side and the downstream side of the communication valve 63 are made to communicate with each other, and the pilot ports 42, 43, 44, 45, 46, 47 of the operating valves 26, 27, 32 and the second
Connect the pilot port 76 of the communication valve 64 to each pilot port 42, 43, 44, 45,
When pilot pressure is applied to at least one of 46 and 47, the second communication valve 64 is switched to the communication position by the pilot pressure, and the third pressure oil supply pipe 5 is switched to the communication position.
9. A hydraulic circuit characterized in that the upstream side and the downstream side of the second communication valve 64 of No. 9 are configured to communicate with each other.