SUNNY internal gear pump has the following characteristics; 1. Adopt the axial and radial pressure compensation design, which can maintain a high volume efficiency even at low rotational speed and low viscosity 2, ultra-low noise, the use of high strength cast iron and the interior of the unique muffler design, so that the noise is lower. 3. Extremely low flow and pressure pulsation, stable flow and pressure output can be maintained at low speed. 4. High pressure design, high pressure up to 35MPa. 5. Wide speed range, high speed up to 3000r/min. 6, can be combined to form a double pump. 7, not sensitive to oil pollution, long service life. 8, can be widely used in industry, such as plastic machine, shoe machine, die casting machinery and forklift industry hydraulic system. It is especially suitable for energy saving system with servo variable frequency drive. Internal gear pump can be reversed transmission, as long as the replacement of motor steering can; Internal gear pump pump body can be turned, the import and export position at right angles, easy to choose the import and export position; The inner gear pump in the pump body, end cover, bearing housing are connected between convenient insulation or cooling medium inlet and outlet interface. Internal gear pump has: no oil phenomenon, smooth transmission, high efficiency, low noise, long service life advantages. There are two kinds of involute tooth shape (Crescent) and cycloid tooth shape (Grout) of the internal gear pump, and its structure is shown in the diagram. The working principle and main characteristics of these two internal gear pumps are the same as the external gear pump. Within the involute tooth profile of gear pump, pinion and internal gear to put a link between the diaphragm, so that separates oil pressure and oil absorption cavity, as shown in figure cycloidal tooth profile gear pump is also called the cycloid rotor pump, in this kind of pump, pinion and internal gear are only one tooth, and therefore do not need to set the partition, as shown in figure of the internal gear pump pinion is driving wheel, wheel as the driven wheel, wheel at work with rotating pinion.