To provide a sound insulating mechanism for a vacuum generating device easy to manufacture and having a simple structure for preventing noise emitted by a vacuum pump from leaking out to the exterior.
The vacuum pump 10 is surrounded by sound insulating walls 50. A cooling fan 60 is fitted on an outer end of a rotary shaft 12 of the pump. A centrifugal fan 70 is fitted on a coupling 40 connecting an inner end of the shaft 12 of the pump to an output shaft 22 of an electric motor. The fresh air outside the walls 50 is supplied to the fan 60 through the interior of a first noise elimination chamber 80. The air is forcibly circulated by the fan 60 around a bearing part 14, a casing 18, and a bearing part 16 of the pump. The air is discharged by the fan 70, through the inside of tube body 100 and the interior of a second sound elimination chamber 90, to the outside of the walls 50.
YAMADA FUMIHIKO
TAGAWA KIYOSHI
