The multi-tooth differential cycloidal gear oil pump (also known as the small-toothed cycloidal pump) is a new type of cycloidal gear oil pump developed at home and abroad in the 1980s. It is used to cut off the equidistance of the non-complete short outer cycloidal line at the top. The curve is used as the profile of the cycloidal (pinion). The conjugated gear adopts a circular arc which is cut by the adjacent arc and then the root of the tooth and the top of the tooth is used as the tooth profile. At present, there are two-tooth difference and three-tooth differential cycloidal gear oil pumps. Compared with the ordinary cycloidal pump, it has the advantages of small flow pulsation and large displacement.
The common internal gear oil pump and the multi-toothed cycloid pump are very similar in the configuration of the tooth profile, such as the equation of the tooth profile curve and the selection of the design parameters.

Multi-tooth differential cycloidal meshing is mainly used in hydraulic and hydraulic motors in hydraulic systems, and can also be used in planetary transmissions.