A complete hydraulic system consists of five parts, namely power components, actuators, control components, auxiliary components and hydraulic oil. The power element plays the role of providing a force source to the system, is an indispensable core element of the system, the hydraulic system is to use the hydraulic pump as a power element to provide a certain flow and pressure to the system, the hydraulic pump converts the mechanical energy output by the prime mover (electric motor or internal combustion engine) into the pressure energy of the working liquid, is an energy conversion device, and the structural form of the hydraulic pump generally has gear pumps, vane pumps and plunger pumps. The role of actuators, such as hydraulic cylinders and hydraulic motors, is to convert the pressure energy of the liquid into mechanical energy to drive the load in a linear reciprocating or rotary motion. Control elements (i.e., various hydraulic valves) control and regulate the pressure, flow and direction of fluids in hydraulic systems. According to the different control functions, hydraulic valves can be divided into pressure control valves, flow control valves and directional control valves. According to different control methods, hydraulic valves can be divided into on-off control valves, fixed-value control valves and proportional control valves. Auxiliary components include oil filters, accumulators, pipe fittings, seals, fuel tanks and heat exchangers.
Advantages of the hydraulic system:
1. Small size and light weight, so the inertia force is small, and when suddenly overloaded or stopped, no big impact will occur.
2. The traction speed can be adjusted smoothly within a given range, and stepless speed regulation can be realized.
3. The commutation is easy, and the conversion of the rotation of the working mechanism and the linear reciprocating motion can be realized more conveniently without changing the rotation direction of the motor.
4. The hydraulic pump and the hydraulic motor are connected by oil pipes, and they are not strictly restricted by each other in terms of space layout.
5. Due to the use of oil as the working medium, the components can be lubricated by themselves relative to the moving surface, with low wear and long service life.
6. The operation and control are simple and the degree of automation is high.
Hydraulic system disadvantages:
1. The use of hydraulic transmission has high maintenance requirements, and the working oil should always be kept clean.
2. The manufacturing accuracy of hydraulic components is required, the process is complex, and the cost is high.
3. The maintenance of hydraulic components is more complex and requires a high technical level.
4. Using oil as the working medium, there is a fire hazard on the working face.
5. Low transmission efficiency.
hydraulic system diagram
hydraulic control systems