A hydraulic pump is a power component of a hydraulic system, whose function is to provide pressure oil to the hydraulic system. From the perspective of energy conversion, it converts the mechanical energy output by the prime mover (such as an engine) into pressure energy of liquid that is easy to transport. Hydraulic motors belong to the category of actuating components, which can convert the pressure energy of input liquid into mechanical energy for output shaft rotation, used to drag loads to do work. According to their structural form, hydraulic pumps and motors can be specifically classified into gear type, blade type, plunger type, and other types.