Hydraulic roller pump for automatic vehicle transmission, has rotor groove angle adapted to roller diameter to reduce risk of breakage

摘要

The normal force (Fn) arising between the ring (2) and roller (7) during pump operation is minimized by adapting the angle (gamma ) of the grooves (6) in the rotor periphery to the roller diameter (Rd). Roller diameter is 2-6 mm. The pump casing contains a driven rotor (4) with a ring around it and a number of substantially cylindrical rollers located in grooves in the rotor periphery. The trailing wall (6a) of the groove is tilted backwards so that the roller is urged outwards in the radial direction by the rotor. The groove angle is defined by an imaginary line (Cs) extending through the center of the groove and the rotor rotation axis and the slanting trailing wall of the groove.