The working principle of the internal gear pump is also to use the change in the seal volume between the teeth to achieve oil suction and oil pressure. The internal gear pump is composed of an oil distribution plate (front and rear covers), an outer rotor (driven wheel), and an inner rotor (drive wheel) eccentrically arranged in the pump body.

The internal gear pump is composed of a transmission shaft, a pinion and a pinion that are integrated with the transmission shaft and mesh with each other and are sleeved on the pump cover. The center of the driven ring gear and the center of the pinion are offset and meshed to form A deep meshing area and an opposite area. In the deep meshing area, the driving tooth surface of the pinion gear and the internal ring gear are in a deep meshing area, the driving tooth surface of the pinion gear is in close contact with the teeth of the internal ring gear, and the pinion tooth tip is in the opposite area It slides on the tooth crest of the ring gear to form a high-pressure cavity for oil pressure and a low-pressure cavity for oil suction.

The working process of the internal gear pump is: when the pinion rotates clockwise, it drives the ring gear to rotate in the pump body, that is, the pinion and the ring gear enter the meshing state, and the top of the pinion and the tooth of the ring gear The effective volume of the gap between them gradually increases, that is, the volume between the teeth gradually increases, forming a vacuum state, and the fluid fills the low-pressure cavity between the hydraulic pump pinion and the ring gear; at this time, because the pinion continues to rotate, the pinion and The area where the ring gear enters the meshing is gradually reduced from the position where the pinion gear and the ring gear mesh shallowly, forming a squeezed state. The pinion tooth top and the inner arc surface of the large crescent block seal the hydraulic oil to death. The oil is drained into the high-pressure cavity of the hydraulic pump, and is squeezed out from a plurality of small radial holes arranged along the circumference in the ring gear, so as to enter the state of being packed in the oil and discharged into the high-pressure cavity. As a result, the state of the high-pressure oil is discharged into the high-pressure chamber.

The tooth profile of the outer rotor of the internal gear pump is a circular arc, and the tooth profile of the inner rotor is an equidistant line of a short outer cycloid.


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