Patent ID: 6893239
Filing Date: 2005-05-17
Classification: F04C

Abstract:
1. An internal geared wheel pump without a filler piece comprising: (a) a housing; (b) an internal geared wheel which rotates in the housing; (c) an externally geared pinion rotatably mounted in the housing, said pinion meshing with the geared wheel and having teeth defining a suction area and a pressure area in the gearing by complete engagement with tooth spaces of the geared wheel and by sealing contact with tooth crowns of said geared wheel in an engagement-free geared wheel area located approximately diametrically opposite the tooth space engagement, the toothing of the geared wheel and the pinion being an involute or cycloid toothing, the tooth crowns having a rounded peripheral surface, the teeth of the pinion and the geared wheel having teeth faces that are symmetric in relation to a center line of each tooth, the rounded peripheral surface of the tooth crowns of the geared wheel and/or the pinion being set-back asymmetrically on the rear tooth face in the direction of rotation for the geared wheel and on the front tooth face in the direction of rotation for the pinion, starting from an uncorrected tooth form designed symmetrically in relation to the center line of each tooth to provide a corrected tooth form in such a way that a transition line between a tooth face and the peripheral surface is located on the rear tooth face in the direction of rotation for the geared wheel and on the front tooth face in the direction of rotation for the pinion, closer to the tooth base than on the opposite tooth face, respectively, wherein the asymmetrically rounded peripheral surface extends continuously between the tooth faces of each tooth.