SHAFT SEALING STRUCTURE OF VACUUM PUMP

摘要

PROBLEM TO BE SOLVED: To improve a preventing effect of oil intrusion into a pump chamber in a vacuum pump. SOLUTION: Annular shaft sealing ring bodies 49 and 50 are engaged with and fixed to rotating shafts 19 and 20 in engaging holes 47 and 48 formed in a rear housing 14. Seal rings 51 and 52 are interposed between the inner peripheral surfaces of the shaft sealing ring bodies 49 and 50 and peripheral surfaces 192 and 202 of the rotating shafts 19 and 20. Spiral grooves 55 and 56 are formed in the outer peripheral surfaces 491 and 501 of the maximum diameter parts of the shaft sealing ring bodies 49 and 50. The spiral grooves 55 and 56 provide a pump operation for transferring fluid from the pump chamber 43 side to a gear storing chamber 331 side in response to the rotation of the rotating shafts 19 and 20.