Patent ID: 8113183

Claim:
A positive displacement supercharger comprising: a rotor housing including a rotor cavity having a surrounding cavity wall; a pair of coactive rotors rotatable in the rotor cavity and correlated to carry air axially from an inlet end of the cavity to an outlet near an outlet end of the cavity for discharge at an elevated temperature; a gear case formed at one end of the rotor housing between a bearing plate and a front cover, the gear case containing a pair of engaged timing gears connected with the pair of coactive rotors for timed rotation thereof, the gear case adapted to contain a permanent charge of lubricating oil for lubricating the gears; the front cover having a cover portion sealingly closing the gear case for retaining the permanent oil charge therein, and a tubular extension supporting a drive shaft drivingly connected to one of the timing gears for driving the pair of coactive rotors in timed relation; and wherein the rotor housing, the bearing plate, the cover portion of the front cover and the tubular extension portion of the front cover each define at least one internal cooling passage in fluid communication with each other to define a coolant jacket for carrying liquid coolant in heat exchange relation with the housing, the bearing plate and the front cover for carrying away excess heat therefrom.