Gerotor mechanism for a screw hydraulic machine

A gerotor mechanism for a screw hydraulic machine, said mechanism comprising

• a stator having inner helical teeth made of a elastoplastic material, e.g. of rubber, and
• a rotor having-outer helical teeth whose number by one tooth is less than that of the stator,
• leads of screw lines in the stator and the rotor being proportional to numbers of their teeth,
• the rotor axis being shifted with respect to the stator axis by the eccentricity value being equal to half of the teeth radial height;
• characterized in that
• profiles of the rotor and/or the stator are outlined in the end cross section thereof in the form of the envelop of the initial contour of a rack-type tool, which contour is formed by conjugation of circle arcs when said initial contour of the rack-type tool is run without sliding along corresponding tool circles,
• the radii of the circle arcs of the initial contour being calculated according to the following expressions:
• ri=K[(π2rw12/4Ez12)+E]/(K+1) or ri=K[(π2rw22/4Ez22)+E]/(K+1),
• i/K,
• where
• ri is the initial radius of the rack-type tool profile,
• K=(0.5 . . . 2) is the initial contour shape coefficient,
• rw1, rw2 are radii of the tool circles of the rotor and the stator, respectively;
• E is eccentricity of meshing,
• z1, z2 are numbers of teeth of the stator and the rotor, respectively;
• rc is the conjugated radius of the rack-type tool profile.