Patent ID: 9528525
Filing Date: 2016-12-27
CPC Classification: F04D

Claim Text:
1. A vacuum pump comprising: a rotor shaft that is rotatably supported by a bearing and driven by a motor to rotate at a high speed; a rotor that is fastened to one end of the rotor shaft in axial direction thereof and is provided with an evacuating function portion which comprises a plurality of rotor vanes and a cylindrical threaded rotor; an engagement portion being provided in a fastening portion of the rotor shaft and the rotor, including an engagement hole formed on one of the rotor shaft and the rotor and an engagement shaft formed on the other of the rotor shaft and the rotor to be inserted into the engagement hole; and a filling member provided in a gap between the engagement hole and the engagement shaft, having shear strength lower than respective shear strengths of the rotor and the rotor shaft, wherein: the gap is formed between an entirety of an outer periphery of the engagement shaft and an entirety of an inner periphery of the engagement hole, so that a fit between the engagement shaft and the engagement hole is a clearance fit; and when the rotor and the rotor shaft are disassembled, the filling member undergoes fracture.