The rotary hydraulic system is one of the most important systems in the hydraulic system of the excavator. It directly affects the safety, operating efficiency, energy consumption and operation comfort of the whole machine. This paper analyzes the constant power hydraulic system of small hydraulic excavator in detail, and splits it into several basic circuits, in order to analyze the operation principle of each circuit and the connection between different circuits; Under the premise, the structure of the multi-way valve rotary coupling spool throttle groove has been improved to simplify the processing process, reduce the processing difficulty, and improve the processing efficiency, and the simulation study of the internal and external flow fields of the new and old valves; The rotary hydraulic system of new and old valves was simulated. The following conclusions are drawn:
(1) Decompose the complex hydraulic excavator system into a few simple basic circuits. It is beneficial to analyze the characteristics of each action in detail and the direction of the hydraulic oil circuit, which is convenient for system improvement and failure analysis.
(2) Obtained the multi-way valve gradually expanding U-shaped groove valve area curve. Using Mathcad software to draw the function of the area of the old valve port, it is found that the change trend of the valve port area is consistent with the characteristics of the rotary motor. At the same time, the area curve of the valve port of the new valve is drawn, and the area curve of the valve port of the new and old multi-way valves is basically consistent. This shows that the turning speed, starting and braking performance of the turning motor have basically not changed.
(3) Compared with the original valve, the steady-state hydrodynamic force of the new valve is reduced. When the spool is steady-state, the left and right oscillations are small, the valve port flow fluctuation is small, and the speed stability of the hydraulic actuator is good; Small, almost zero, effectively reducing the additional resistance of the main spool brought by the lateral force, preventing the main spool from appearing inflexible, stuck, or stuck.
(4) Through the AMESim system simulation of the rotary hydraulic system, it was found that the inlet and outlet pressure, output flow rate, output torque, etc. of the motor in the new valve rotary system basically matched the original valve system.
This article has some innovations in the following aspects:
(1) Establish a geometric calculation model and derive the formula for calculating the valve area of the gradually expanding U-shaped groove processed by the end mill.
(2) Based on the principle of unchanged performance, the structure of the multi-way valve spool throttle groove is improved to simplify the processing technology and improve the processing efficiency.
