Patent ID: 7819645
Filing Date: 2010-10-26
Classification: F04C

Abstract:
1. An internal gear pump that transports a fluid by taking in and discharging the fluid when an inner rotor and an outer rotor mesh together and rotate using a change in volume of cells that are formed between tooth surfaces of the two rotors, comprising: the inner rotor on which are formed “n” (“n” is a natural number) external teeth; the outer rotor on which are formed “n+1” internal teeth that mesh with the external teeth; and a casing in which are formed an intake port through which the fluid is taken in and a discharge port through which the fluid is discharged, wherein a first angle that is formed by a first straight line that connects a rotation axis of the inner rotor to a tooth tip of an external tooth, and a second straight line that connects the rotation axis to a meshing portion of the external tooth is not less than 1.4 times a size and not more than 1.8 times the size of a second angle that is formed by a third straight line that connects the rotation axis to a tooth bottom of the external tooth, and the second straight line.