Lifting speed is one of the most intuitive indicators to evaluate the working performance of electric forklifts, which directly affects the overall operation efficiency of material handling scenarios such as warehouses, manufacturing workshops and logistics stations. Many equipment operators and maintenance personnel usually pay attention to the state of power battery and lifting mechanical structure, but easily ignore the decisive influence of hydraulic oil flow parameters on lifting speed performance.

The first core parameter is the rated output flow of the hydraulic pump. This parameter defines the volume of hydraulic oil that the power unit can deliver to the lifting circuit per unit time under rated working conditions. Under no-load or regular load conditions, the lifting speed is positively correlated with the effective output flow of the hydraulic pump within the allowable working range. Reasonable matching of the pump output flow and the internal cavity volume of the lifting hydraulic cylinder can avoid problems such as excessively slow idle lifting speed or frequent overflow of the system under common load conditions.

The second key parameter is the opening flow characteristic of the distribution valve. The flow rate passing through the spool valve port is closely related to the opening cross-sectional area corresponding to different handle operation strokes. When the flow parameter of the valve port is calibrated properly, the forklift can realize stepless adjustment of lifting speed following the change of the handle stroke, and avoid sudden jump at the initial stage of lifting or obvious stuttering in the middle of the stroke.

The third important parameter is the flow coefficient of the oil return circuit. The damping level of the return pipeline and the flow limiting setting of the return filter will affect the smoothness of hydraulic oil circulation. Unreasonable flow coefficient setting will lead to unstable back pressure of the system, which will not only cause abnormal jitter during the lowering process, but also reduce the effective flow entering the lifting chamber to a certain extent, resulting in unexpected drop of lifting speed under partial load conditions.

The fourth influential parameter is the through-flow threshold of the system overflow valve. This parameter determines the allowable maximum flow that can be input to the lifting circuit before the overflow valve opens for pressure relief. If the threshold flow is set improperly, part of the hydraulic oil will be discharged through the overflow valve in advance under normal working load, which will reduce the actual flow entering the lifting cylinder and make the lifting speed lower than the rated design value.

In daily equipment use and maintenance, users should not adjust the above hydraulic oil flow parameters arbitrarily without professional guidance. It is recommended to combine the common load range and operation scenario requirements to carry out regular parameter check and calibration, so as to balance the lifting speed performance and the long-term stable operation life of the electric forklift.