SHAFT SEAL DEVICE FOR OIL-SEALED ROTARY VACUUM PUMP

摘要

PURPOSE:To prevent oil leakage to the outside keeping good lubricating condition on a bearing and a seal member by providing an oil sump part formed between a seal member on the rotor side of a pair of seal members and a bearing, and a first communicating part to communicate the oil sump part to the vicinity of a discharge port in a cylinder. CONSTITUTION:Pressure in the vicinity of the discharge port of a cylinder 4 is applied on an oil sump part 9 through an oil introducing passage 11, a part of discharged oil from the cylinder 4 is introduced to the oil sump part 9, hereafter returned into the cylinder 4 through a sliding part of a bearing 7. Nextly, pressure rise in the clearance part 17 between a pair of seal members 8, 16 is prevented by a pressure relief passage 18, and oil intruded from the oil sump part 9 to the clearance part 17 is returned to an oil case through the pressure relief passage 18.