| 摘要 |
A rotor shaft sealing structure of an oil-free rotary compressor is provided, with which is reduced a risk of occurrence of lubrication oil intrusion into the compression chamber ( 9 ) of the compressor which is liable to occur when negative pressure is produced in the compression chamber ( 9 ). The rotor shaft sealing structure is composed such that two shaft seal means ( 20, 30 ) are provided in the rotor casing ( 1 ) between the oil lubricated bearing ( 10, 10' ) and the compression chamber ( 9 ) such that an annular airspace ( 24 ) is formed between the two shaft seal means ( 20,31 ), at least one communicating hole ( 34,34' ) is provided to communicate the annular airspace ( 24 ) to the outside of the rotor casing ( 1 ), and the annular airspace ( 24 ) of the male rotor shaft ( 6 ) sealing part and the annular airspace ( 24 ) of the female rotor shaft ( 7 ) sealing part are connected by a between-rotor shaft communication passage ( 35 ).
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