When the cam pushes the plunger upwards, the seal volume formed by the plunger and the cylinder body is reduced, and the oil is squeezed out of the seal volume and discharged to the place where it is needed through the one-way valve.
When the cam rotates to the lower part of the curve, the spring forces the plunger down to form a certain degree of vacuum, and the oil in the oil tank enters the sealed volume under the action of atmospheric pressure.
The cam makes the plunger rise and fall continuously, the sealing volume periodically decreases and increases, and the pump continuously sucks and discharges oil.
