Hydraulic pumps are mechanical devices that convert mechanical power into hydraulic energy. They work by using an electric motor or other source of mechanical power to drive a piston or other type of reciprocating element, which moves fluid through the pump and into a hydraulic system.

There are two main types of hydraulic pumps: positive displacement pumps and variable displacement pumps. Positive displacement pumps work by trapping a fixed volume of fluid in a chamber and then moving that fluid into the hydraulic system. This type of pump is often used in applications where a constant flow of fluid is required, such as in construction equipment or industrial machinery.

Variable displacement pumps, on the other hand, are able to vary the volume of fluid they deliver based on the needs of the hydraulic system. These pumps are often used in applications where the demand for fluid flow changes frequently, such as in vehicles with hydraulic steering systems.

In both types of pumps, the movement of the piston or other reciprocating element is controlled by a valve system, which regulates the flow of fluid through the pump and into the hydraulic system. The pressure of the fluid in the system is also regulated by a pressure relief valve, which prevents the system from being damaged by excess pressure.

Overall, hydraulic pumps are essential components of many types of machinery and equipment, and they play a vital role in the operation of many systems that rely on the use of hydraulic fluid to transmit power and perform work.