The main hydraulic system of the excavator

The main hydraulic system is driven by the main pump assembly. The main pump assembly has two inclined-axis variable displacement piston pumps (upper and lower), which have the same performance and usage. The lower pump is directly connected to the flexible coupling. The engine is connected. The pilot gear pump is in the main pump housing to provide pressure oil for the remote pilot operating system. The load of these three pumps constitutes the full load of the engine.

At empty load, the flow rate of each main pump is 214L/mino when the excavator is not working. Oil discharged from two main pumps

The multi-way valve is all returned to the hydraulic tank. At the same time, the main operating valve (multi-way valve) feeds back the signal of the small load to the cylinder of the main pump.

Inclination control mechanism - electromagnetic proportional pressure reducing valve, reducing the displacement of the main pump, thereby reducing the output power of the engine.

When performing separate or combined actions, the maximum working pressure of the main hydraulic system is limited by the main relief valve, each stage is changed

The maximum working pressure to the valve is set by the secondary relief valve (overload valve). The setting of the main relief valve of the triple and quadruple multi-way valve

The pressure is 35. 2MPa, the set pressure of the arm control circuit is 30. OMPa, the set pressure of the boom control loop is

21. The setting pressure of the bucket control circuit is 30. 6MPa, the setting of the relief valve of the travel control circuit

The pressure is 36. 7MPa (the flow rate is 40L/min) d

1. Load selection control

The S280F2 excavator main pump uses a load type control system, which is designed to improve work efficiency during operation.

Reduce fuel consumption. The main pump load type control excavator spare parts system is as follows. Select different load types (L, S, H), main

The pump's output power characteristics (P-Q characteristics) are different, as shown in the figure below.

2. Rotary short circuit

When the switch at the rear of the right operation panel is closed, the electromagnetic reversing valve in the main hydraulic system is reversed, and the swing mechanism is released.

Move. The electromagnetic reversing valve installed on the left and right pipelines of the swing motor is reversed to connect the pipelines on the left and right sides to make the swing loop

It becomes the open state. When the rotation is stopped, the swing device maintains the state of mechanical brake (hydraulic oil overflow). https://jnjmzm.wixsite.com/sdjygcjx