Internal geared wheel pump without a filler piece

摘要

The invention relates to an internal geared wheel pump without a filler piece, comprising a housing, an internal geared wheel (3) which rotates in the housing and an external geared pinion (2) which is rotationally mounted in the housing and which meshes with the geared wheel. The teeth of the pinion define a suction area and a pressure area in the gearing, by complete engagement with the tooth spaces fo the geared wheel and by sealing contact with tooth crows of the geared wheel in an engagement-free geared wheel area which lies approximately diametrically opposite the tooth space engagement. The toothing of the geared wheel and the pinion is an involute or cycloid toothing, the tooth crowns having a rounded peripheral surface (23, 34). The tooth crows of the geared wheel (3) and/or the pinion (2) are asymmetrically rounded in relation to a centre line (40) of each tooth (22, 33), in such a way that a transition line (42) between the tooth face (24, 35) and the peripheral surface (41) is located on the rear tooth face (35) (in the direction of rotation) for the geared wheel and on the front tooth face (24) (in the direction of rotation) for the pinion, closer to the tooth base than on the opposite tooth face, respectively.