ROTARY UNIT

摘要

A rotary unit includes a supercharger rotary shaft, an impeller fitted to the supercharger rotary shaft and operable to pressurize a fluid medium sucked from one end portion side of the supercharger rotary shaft, and a fastening member to fix the impeller to the supercharger rotary shaft while pressing the impeller in a direction axially of the supercharger rotary shaft. The fastening member includes an internal thread portion defined in an interior thereof and engageable with an external thread portion of the supercharger rotary shaft. An outer surface of a tip end portion of the fastening member is so formed as to represent a diametrically constricted shape in which it is continuously smoothly tapered in a direction away from the impeller.

主权项

1. A rotary unit which comprises:
a rotary shaft; an impeller fitted to the rotary shaft and operable to pressurize a fluid medium sucked from one end portion side of the rotary shaft; and a fastening member fitted to one end portion of the rotary shaft and operable to fix the impeller to the rotary shaft while pressing the impeller in a direction axially of the rotary shaft, wherein: the fastening member comprises an internal thread portion defined in an interior thereof, the internal thread portion being engageable with an external thread portion of the rotary shaft; and the fastening member has a tip end portion, an outer surface of which tip end portion protrudes axially from one end face of the rotary shaft and is formed to represent a diametrically constricted shape in which the outer surface is tapered in a direction axially away from the impeller.