The working principle of an oil pump

There are many types of oil pumps, such as gear pumps and screw pumps. I’m not sure which type the original poster is referring to

Oil pumps include centrifugal pumps, positive displacement pumps, screw pumps, and gear pumps; each type of pump has a different structure

The working principle of oil pumps was published on 2009-07-01 15:53:14. Currently, fuel pumps installed inside the fuel tank are those that are most commonly used. It consists of a turbine pump, a pressure relief valve, and a residual pressure check valve. A turbine pump is driven by an electric motor that draws fuel from the fuel tank; the electric motor needs to be cooled and lubricated by the fuel, and a decrease in fuel level may cause the motor to burn out ； The function of the pressure relief valve is to open and release excess oil when the pressure at the outlet of the oil pump exceeds the specified value ； The function of the residual pressure check valve is to close when the oil pump stops operating, thereby retaining the residual oil pressure to facilitate restart. The oil pump has its operation controlled by the engine speed signal (the oil pump stops working when the engine is not running). The details are as follows: 1. Control elements of the oil pump: ① Spool valve: It is a three-position three-way valve, consisting of a spool and a sleeve that can move relative to each other. The movement of the valve core is balanced by a primary piston and a secondary piston at the right end of the valve core, together with a spring at the left end of the valve core. The movement of the sliding sleeve is controlled by the swashplate piston; it moves in conjunction with the swashplate piston, taking on the same distance and direction of movement as that piston. ②Secondary piston: In electric control mode, the pilot secondary oil flow controls the secondary piston independently; negative flow does not participate in direct control. Instead, a negative pressure sensor measures its pressure parameters, which are sent to the computer. The computer then uses these values as a parameter to control the current of the electric proportional valve, thereby regulating the pilot secondary oil flow ； In the hydraulic control mode, the pilot secondary oil flow is blocked by the hydraulic-to-electric control valve and does not participate in the control of the secondary piston; instead, negative flow rate is used solely to directly control the secondary piston. The working direction of the secondary piston is to push the spool of the slide valve to the left, with the spring built into it providing the force for return and thus achieving balance. ③Primary piston: Controlled by the front pump oil flow, the rear pump oil flow, and the pilot primary oil flow (only in hydraulic control mode). Its operating direction is to push the spool valve core to move to the left, with a built-in spring providing the force for return, thus achieving balance. 2. Displacement control of the oil pump: front pump oil flow, rear pump oil flow, pilot secondary oil flow, and negative flow. Among these, the front pump oil flow controls the primary piston; the rear pump oil flow controls both the primary piston and the swashplate piston (one end controls the small end of the swashplate piston and remains in an open state, another end controls the large end and remains in a closed state, while yet another end controls the main pressure piston); negative flow controls the primary piston, and the pilot secondary oil flow controls the secondary piston. 3. Actuating element — variable piston: The variable piston consists of a fixed piston sleeve and a plunger with different cross-sectional areas at its two ends; the plunger is connected to the swash plate and the spool sleeve. When a pressure difference is generated due to pressure on these two end faces, the plunger drives the other two components to move as well.

Thanks, 4th floor! Due to a lack of knowledge, the questions asked were rather broad. Hehe

There are many types of oil pumps: screw pumps such as single-screw, twin-screw, and triple-screw pumps; centrifugal pumps; gear pumps, and many other types. Each type has a different working principle

So-called oil pumps are classified according to the medium they transport. Pumps used for transporting various types of oils are collectively referred to as oil pumps. However, there are many different types of oils, with varying viscosities, temperatures, and compositions; accordingly, different pumps are required, and their structures also differ. It would be helpful if the question were more specific

A gear pump operates by the mutual engagement of two gears, and it has low requirements regarding the medium. The normal pressure is below 6 MPa, with a high flow rate. A gear oil pump contains a pair of rotating gears within its pump body – one active and one passive. Through the intermeshing of these two gears, the entire working chamber inside the pump is divided into two separate sections. A is the intake chamber, and B is the discharge chamber. When the gear oil pump is in operation, the driving gear causes the driven gear to rotate; as the gears move from engagement to disengagement, a local vacuum is created on the suction side (A), and liquid is drawn in. The liquid that has been drawn in fills the gaps between the teeth of the gear and is carried to the discharge side (B); when the gears engage, the liquid is forced out, forming high-pressure liquid that is then discharged from the pump through its outlet.