| 摘要 |
PROBLEM TO BE SOLVED: To provide an oil free screw compressor in which the peripheral speeds of bearings on the suction sides or the discharge sides of rotors are reduced. SOLUTION: This oil free screw compressor comprises the male rotor 1 and the female rotor 2 having spiral teeth and rotating in engagement with each other, a casing 3 housing the male rotor 1 and the female rotor 2 and forming a compressing and operating chamber, the discharge side bearings 8A, 8B and suction side bearings 9A, 9B rotatably supporting the male rotor 1 and the female rotor 2, and oil seals 13A, 13B, 17A, 17B so installed that a grease lubricating the discharge side bearings 8A, 8B and suction side bearings 9A, 9B does not intrude into the compressing and operating chamber. One of the discharge side bearings 8A, 8B and the suction side bearings 9A, 9B, for example, the suction side bearings 9A, 9B are needle roller bearings. The compressor comprises cylindrical parts 18A, 18B fitted to the outer peripheral sides of the needle roller bearings and having outer diameter dimensions larger than the outer diameter dimensions of the corresponding oil seals 17A, 17B. COPYRIGHT: (C)2007,JPO&INPIT
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