What is hydraulic system in a forklift? What is the working principle？
Hydraulic Actuator - Gear Pump
Function: Convert the mechanical energy output by the diesel engine into the pressure energy of the hydraulic oil, as the power mechanism in the hydraulic system
Working principle
When the gear rotates in the direction shown in the figure, the gear teeth in the oil suction chamber on the right side are disengaged, and the volume of the sealing chamber increases continuously, which constitutes the oil suction and is brought into the oil pressure chamber on the left side by the rotating gear teeth. The gear teeth in the left oil pressure chamber are continuously engaged, which reduces the volume of the sealing chamber, and the oil is squeezed and discharged to the system. This is the oil suction and oil pressure process of the gear pump. The contact line of the tooth surface at the meshing point has always played the role of separating the high and low pressure chambers, so there is no need to set a special distribution mechanism in the gear pump.
Hydraulic control mechanism - multi-way valve
Function: Control the direction, flow and pressure of liquid flow to ensure that the working device can work smoothly and harmoniously
At present, the forklift adopts CDB new multi-way valve, chip structure, integrated sliding reversing valve, diverter valve and overflow valve.
Sliding directional valve
Function: Use the relative movement between the valve core and the valve body to open and close the oil circuit, thereby changing the direction of the liquid flow, so that the hydraulic actuator can start, stop or change the direction of movement
Structure: main body and manipulation and positioning mechanism
Diverter valve
Function: Provide hydraulic oil with constant flow and pressure to the steering gear for use in steering
Relief valve
Function: keep the pressure in the hydraulic system basically constant and prevent the system from overloading
Principle: When the system is working normally, the valve port is closed, and the output flow of the hydraulic pump all enters the actuator. When the system is overloaded, when the pressure of the system exceeds the set value of the relief valve, the relief valve opens quickly, the oil flows back to the oil tank, and the system pressure does not increase, ensuring the safety of the system.
CDB's new multi-way valve adopts a direct-acting relief valve, as shown in the figure, which uses the hydraulic pressure acting on the effective area of the valve core to directly balance the spring force to work.
Speed limiter valve
Function: Prevent the goods from falling rapidly due to hydraulic system failures such as operation errors or oil pipe ruptures.
Structure: one-way throttle relief valve
Installation location: near the oil inlet of the hydraulic lifting cylinder
