Patent ID: 9291155
Filing Date: 2016-03-22
CPC Classification: F04B,F04C,H02K

Claim Text:
1. A vacuum pump motor which is coupled to a pump main shaft of a vacuum pump, comprising: a motor rotor which is disposed directly or indirectly on the pump main shaft; a motor stator which is fixed to a motor frame concentrically with respect to a rotating axis of the pump main shaft; and balance rings each of which includes a first portion extending in a direction of the rotating axis of the pump main shaft, and wherein each first portion is disposed directly or indirectly on to make contact with the pump main shaft, and wherein the balance rings each include a second portion extending in a direction at a right angle to the rotating axis of the pump main shaft, wherein the second portions are disposed at opposite ends of the pump main shaft, and further wherein the second portions are spaced apart from opposite end portions of a rotor core, wherein the balance rings contain a material having anticorrosion properties, wherein each of the balance rings has an L-shaped cross-section formed by the first portion and the second portion, and wherein end rings are provided at opposite end portions of the rotor core such that a predetermined gap is defined between the end rings and the first portions of the balance rings and a predetermined gap is defined between the end rings and the second portions of the balance rings.