The hydraulic transmission system of construction machinery, like the mechanical transmission system and the electric transmission system, is one of the important transmission systems of the whole transmission system of construction machinery. Because it has the advantages of simple machinery, light weight, small impact on work balance, stepless speed regulation and large adjustment range, and easy automation, it has developed rapidly in recent years and has become one of the important fields of high technology.
The hydraulic system is composed of three parts: hydraulic oil tank, DENISON hydraulic pump device and hydraulic control device. The hydraulic oil tank is equipped with an air filter, an oil filter, a liquid level indicator and a cleaning hole, etc. The hydraulic pump device includes different hydraulic pumps of the same type, drive motors and couplings between them. Hydraulic control device refers to the various valve components and their connecting bodies that make up the hydraulic system. A complete hydraulic system 2 consists of five parts, namely power components, actuators, control components, auxiliary components (accessories) and hydraulic oil.
The function of the power element is to convert the mechanical energy of the prime mover into the pressure energy of the liquid, which refers to the oil pump in the hydraulic system, which provides power to the entire hydraulic system. The structure of DENISON Denison hydraulic hydraulic pump generally includes gear pump, DENISON Denison hydraulic vane pump and plunger pump. The function of the actuators (such as hydraulic cylinders and hydraulic motors) is to convert the pressure energy of the liquid into mechanical energy, and drive the load to perform linear reciprocating motion or rotary motion. Control elements (ie, various hydraulic valves) control and regulate the pressure, flow and direction of liquids in hydraulic systems.
The main requirement of construction machinery for the hydraulic system is to ensure that the poetry host has good working performance. For this purpose, the hydraulic system should meet the following requirements:
1. When the main engine works under the conditions of large changes in the working load and sharp shocks and vibrations, the system must have sufficient reliability.
2. The system should have complete safety devices, such as actuators that can realize safety protection surface unloading, buffering and speed limiting devices when overloaded.
3. Reduce the heating star of the system to ensure that the hydraulic oil temperature does not exceed 65 degrees when the system works continuously.
4. Emergency energy should be considered for large construction machinery. When the prime mover fails, the working mechanism can be returned to a safe state under the action of gravity. In order to reduce the labor intensity of the driver, pilot control can be used. According to different control functions, DENISON hydraulic valve can be divided into pressure control valve, flow control valve and directional control valve. Pressure control valve is further divided into benefit flow valve (safety valve), pressure reducing valve, sequence valve, pressure relay, etc.; meteor control valve includes throttle valve, regulating valve, diverter collecting valve, etc.; directional control valve includes check valve, Hydraulic control check valve, shuttle valve, reversing valve, etc. According to different control methods, hydraulic valves can be divided into on-off control valves, fixed value control valves and proportional control valves.
