| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of oil leakage during long-term use and the contamination of a case and the parts near the same by keeping the pressure of the oil in the case lower than the atm. pressure outside the case. SOLUTION: Gas 28 (dry air or gaseous nitrogen, etc.) is put into the upper part in the case 10 without completely filling up the inside of the case with the oil 24. For example, the pressure of the gas 28 is equal to the atm. pressure outside the case 10 in the state right after hermetic sealing of the case 10. The gas is, thereupon, partly sucked by connecting a suction device to a nipple 30. Consequently, the pressure of the oil 24 drops. The suction is stopped and the nipple 30 is sealed, when the pressure of the oil 24 near at least an oil seal 26 drops below the pressure outside the case 10. If the pressure of the oil 24 is lower than the pressure outside the case 10, the oil 24 does not leak to the outer side of the case 10 even if the function of the oil seal 26 is insufficient. |
