Oil-free fluid machine having two or more rotors

Abstract

An oil-free fluid machine unit is provided of which the fluid machine has two or more rotors and torque transmission between the rotors can be performed without a need of using lubrication oil thereby eliminating contamination induced by lubrication oil and without reduction of longevity of the synchronizing gears. The drive shaft 12 of the drive motor 11 is connected to the rotor shaft 14 of the fluid machine, synchronization gears 18 and 19 are attached to the rotor shafts 14 and 15 at the motor 11 side end of the rotor shafts respectively, and pulleys 16 and 17 are attached to the rotor shafts 14 and 15 at the other side ends respectively opposite to the motor 11 and a belt is looped over the pulleys so that the pulleys are rotated in counter direction to each other. At least one of the synchronization gears is made of plastic material. Thus, torque transmission between the rotors is done in two ways, via synchronization gear drive and belt drive.

1 . An oil-free fluid machine unit comprising an oil-free fluid machine, a motor connected to one of rotor shafts of the fluid machine, and a mounting base for mounting the fluid machine and the motor, the fluid machine having a rotor casing and two or more lobed rotors accommodated in the rotor casing rotatably to expel gas trapped in pockets formed between the lobes and the rotor casing as the rotors rotate; wherein a pulley is attached to each of said rotor shafts at an end opposite to the motor side end thereof, a belt being looped over pulleys attached to adjacent rotor shafts so that pulleys attached to adjacent rotor shafts are rotated in counter direction to each other; and synchronization gears are attached to the other ends of the rotor shafts respectively, at least one of the synchronization gears being made of plastic material; whereby torque transmission between the rotors is carried out in two ways, via belt driving and via synchronization gear drive. 
   
   
       2 . An oil-free fluid machine unit according to  claim 1 , wherein an idler pulley is provided to allow pulleys attached to adjacent rotor shafts to be rotated in counter direction to each other by looping a belt over the adjacent pulleys via the idler pulley.