Among the existing hydraulic pumps, the working pressure of gear pumps is second only to that of plunger pumps. In addition to their small size and low price, they are widely used in mobile equipment and vehicles as the pressure oil source for hydraulic working systems and steering systems. On the other hand, because the gear pump has a large speed and displacement range, strong oil absorption capacity, and low cost, it is also often used as an auxiliary pump for various hydraulic systems, such as liquid supplement pumps and pilot control systems in closed loops. In the low pressure control oil source, etc. However, in the field of fixed hydraulic equipment, due to the large flow pulsation, high noise and limited life of external gear pumps, it has become increasingly unpopular as the main pump, and its use is limited to auxiliary pumps and pre-pressure pumps operating at low pressure. On the contrary, the internal gear pump is one of the hydraulic pumps with the lowest noise and the best comprehensive performance.

In addition to the slightly higher price, it is almost better than external gear pumps in other aspects. The development of modern manufacturing technology will greatly reduce the cost gap between internal and external gear pumps. In the industrial field, the increasing popularity of speed-regulating electric transmission technology will largely make up for the invariable shortcomings of internal gear pumps. It can be expected that the application of internal gear pumps in fixed and mobile equipment will expand rapidly in the future. In hydraulic engineering, the cycloid gear pump has the advantages of small size, low price and strong self-priming ability. Pressure) is used, and sometimes used as the main pump of some machine tool hydraulic systems.

This kind of oil gear pump can realize one-way fuel supply and has nothing to do with input steering. This performance has special significance for emergency steering and braking systems that need to be driven by wheels on certain vehicles or mobile machinery. The cycloid gear pair (Orbit meshing pair) with a fixed pin gear ring has a large displacement per unit volume, but because of its low allowable speed, it is mostly used as a low-speed hydraulic motor. It is only used as a hydraulic steering system for vehicles. The metering pump is used. When the power oil source in the system fails, the pump can be used as an emergency oil source manually.