An oil pump is a common mechanical device used to transport liquids (usually liquid fuel or lubricating oil) from one place to another. It has a wide range of applications in many fields, including the automotive industry, aerospace, shipbuilding industry and industrial production, etc.
The working principle of an oil pump can be simply described as: moving liquid from a low-pressure area to a high-pressure area through the pressure generated by mechanical movement. The following will introduce in detail the working principles of two common oil pumps.
1. Working principle of gear pump:
The gear pump is a common positive displacement pump consisting of two gears meshing with each other. One gear is called the driving gear and the other is called the driven gear. When the driving gear rotates, the driven gear also rotates. The liquid enters the pump chamber through the gap between the gears and is pushed to the outlet as the gears rotate. Due to the meshing of the gears, the liquid is gradually compressed in the pump chamber and pushed to the high-pressure area.

2. Working principle of piston pump
A piston pump is a pump that uses a piston to reciprocate in a pump chamber to push liquid. It consists of one or more pistons, cylinders and valves. When the piston moves forward, the pressure in the pump chamber decreases and liquid enters the pump chamber through the air inlet valve. As the piston moves backward, the inlet valve closes, pressure increases, and liquid is pushed toward the outlet. The outlet valve then opens and the liquid is released into the high pressure area. Repeating this process, the liquid will be continuously transported from the low pressure area to the high pressure area.
The working principles of these two oil pumps are based on the pressure difference of the liquid to achieve liquid transportation. Through the movement of mechanical equipment, the liquid is compressed or pushed, thereby forming a certain pressure, allowing the liquid to flow. Oil pumps usually consist of a pump body, a pump chamber, a driving device, valves and other components to realize the transportation and control of liquids.