Vacuum pump with rotor shaft supported by friction bearings

A mechanical automotive vacuum pump comprising:

• a housing comprising a housing cylindrical bearing surface;
• a pumping chamber arranged in the housing;
• a pump rotor configured to be rotatably supported by the housing, the pump rotor comprising a rotor body which comprises a rotor body bearing section and a chamber section,
• wherein,
• a radial vane slit is arranged at the chamber section,
• a rotor body cylindrical bearing surface is arranged at the rotor body bearing section, and
• the rotor body bearing section comprises a circular lubrication ring groove;
• a pump vane configured to be radially shiftable, the pump vane being supported in the radial vane slit;
• a friction bearing defined by the rotor body cylindrical bearing surface and the housing cylindrical bearing surface;
• and
• a lubricant pump connector,
• wherein,
• the housing cylindrical bearing surface comprises a lubrication inlet opening which is arranged to lie in a same transversal plane as and opposite to the circular lubrication ring groove,
• the lubrication inlet opening is directly connected to the lubricant pump connector at the housing,
• the cylindrical chamber section further comprises a first rotor body diameter,
• the rotor body bearing section further comprises a second rotor bearing diameter, and
• the first rotor body diameter is identical with the second rotor body diameter.