Scroll fluid machine having a cooling passage inside the drive shaft

A scroll fluid machine comprising:

• first and second stationary scrolls provided with spiral wraps extending from central parts of respective end plates of the scrolls toward outer peripheral edges thereof;
• a revolving scroll with double spiral wraps provided on both sides of a central plate of the revolving scroll and engaging said spiral wraps of said stationary scrolls, said revolving scroll being disposed between the first and second stationary scrolls;
• and
• a drive shaft, connected to a motor, to which said revolving scroll is drivingly connected, the drive shaft penetrating a center of the end plate of the first stationary scroll from the outer part of the scroll, being connected to a center part of said revolving scroll, extending to the second stationary scroll, and being held by and revolvably engaging the first and second stationary scrolls;
• the drive shaft including a cooling passage formed therein which opens to an outer part of the second stationary scroll, extends through the center part of the revolving scroll, and exits at the first stationary scroll so that cooling gas is sucked from one end and exhausted from the other end of the cooling passage so as to cool the center part of the revolving scroll, and at least one fan being provided adjacent the cooling passage to exhaust the cooling gas from the cooling passage.