The function of a manual hydraulic pump is to convert the mechanical energy of a power source (such as an electric motor and an internal combustion engine) into the pressure energy of a liquid.

Operation Principle: The cam is rotated by an electric motor. As the cam pushes the plunger upward, the sealed volume between the plunger and cylinder decreases, and the oil is forced out through a one-way valve to the required location. When the cam rotates to the descending part of the curve, the spring forces the plunger downward, creating a certain vacuum, and the oil in the oil tank is drawn into the sealed volume under the action of atmospheric pressure. The cam causes the plunger to continuously rise and fall, resulting in a cyclic reduction and increase of the sealed volume, thereby continuously suctioning and discharging oil.