Internal gear pump having an eccentric inner rotor and outer rotor having teeth non-trochoid tooth profiles and a moving center of the outer rotor

摘要

An internal gear pump in which an inner rotor and an outer rotor are arranged in a rotor housing chamber. A deepest meshing section is located in the vicinity on a line connecting a center of the inner rotor and a center of the outer rotor. A center of the rotor housing chamber is offset, from a position in which the center and the center of the outer rotor coincide with each other, to the deepest meshing section side by an amount smaller than a tip clearance, which is a gap between the tooth tip of the inner rotor and the tooth tip of the outer rotor in the vicinity of a seal land between a terminal end side of an intake port and a start end side of a discharge port.

主权项

1. An internal gear pump, comprising:
a housing defining a rotor housing chamber and an intake port and an discharge port, the intake port and the discharge port being in fluid communication with the rotor chamber housing, the housing including a seal land disposed in the rotor housing chamber intermediate the intake port and the discharge port; an inner rotor including teeth; and an outer rotor including teeth, the inner rotor and the outer rotor being disposed in the rotor housing chamber so that the teeth of the inner rotor and the teeth of the outer rotor mesh therewith and the internal gear pump further having a deepest meshing section side located within the rotor chamber housing disposed on a plane passing through the axial center of the inner rotor and the axial center of the outer rotor, each tooth of the inner rotor and the outer rotor has a tooth profile, and the inner rotor and the outer rotor are further arranged in the rotor chamber housing so as to satisfy the equation:
e>d/[2(N−2)], where eccentricity is set to e, where a tooth bottom diameter of the inner rotor is set to d, and where the number of teeth of the inner rotor is set to N, wherein the axial center of the rotor housing chamber is movingly offset during operation of the internal gear pump from a position in which the axial center of the rotor housing chamber and the axial center of the outer rotor coincide with each other toward the deepest meshing section side of the rotor chamber housing by an amount smaller than a tip clearance, wherein the tip clearance is a gap between a tooth tip of the inner rotor and a tooth tip of the outer rotor on the seal land between a terminal end side of the intake port and a start end side of the discharge port, the seal land being disposed on another side of the rotor chamber housing opposite to the deepest meshing section side, and wherein the tooth profile of each tooth of the inner rotor and the outer rotor is not a trochoid tooth profile.