Electrical machine with a stator, and a claw pole rotor system composed of two pole wheel halves

An electrical machine formed as a fluid-cooled three-phase alternating current generator, comprising a cup-shaped housing;

• a stator arranged in said housing;
• a drive system;
• a shaft driven by said drive system;
• a claw pole rotor system mounted on said shaft, said claw pole rotor system including a first pole ring which is mounted on said shaft, formed as a pole wheel half and has claws, and a second pole ring which is formed as a pole wheel half and also has claws, so that tips of the claws of one of said pole rings extend in gaps between the claws of the other pole ring;
• pole rings producing a cooling air stream in said housing for withdrawing heat which is generated in the machine by convection through an outer casing of said housing to fluid medium which surrounds said housing;
• blower means including a plurality of substantially radially extending blower vanes formed on substantially flat end side of a respective one of said pole rings which is located at a side opposite to said drive system;
• and a ring chamber closing said blower vanes in an axial direction and formed as a part of a housing bottom, said ring chamber having a bottom provided with substantially radially extending ribs which form grooves therebetween, said grooves being located at a height of said blower vanes, said ribs from said bottom of said ring chamber being straight.