| 摘要 |
Provided is an exhaust pump that is suitable for enhancing durability, processability of connecting opening portions in a pump production stage, and evacuation performance. An exhaust pump includes: a cylindrical rotating member; a support unit of the cylindrical rotating member; a driving unit for rotationally driving the cylindrical rotating member; an outer cylindrical fixed member disposed so as to surround the outer periphery of the cylindrical rotating member; an inner cylindrical fixed member disposed so as to be surrounded by the inner periphery of the cylindrical rotating member; a helical outer thread groove exhaust passage provided between the cylindrical rotating member and the outer cylindrical fixed member; a helical inner thread groove exhaust passage provided between the cylindrical rotating member and the inner cylindrical fixed member; connecting opening portions that are opened in the cylindrical rotating member and that lead a part of gas existing in the vicinity of the outer periphery of the cylindrical rotating member towards the inner thread groove exhaust passage. A gap between an upstream end of the connecting opening portions and lowermost stage rotor blades provided at the outer periphery of the cylindrical rotating member which is located upstream of the connecting opening portions has a dimension equal to or greater than a dimension that enables insertion, into the gap, of a tool for opening the connecting opening portions.
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