SHAFT SEALING DEVICE FOR AN ELECTRIC MOTOR

摘要

A shaft sealing device for an electric motor provided at at least one end of an output shaft (20) of an electric motor (10) and at one end of a stator housing (14) confronting the one end of the output shaft, the shaft sealing device comprising a stationary rim (32) provided on the stator housing (14) and a rotary rim (34) provided in a shaft end area (20a) of the output shaft (20), and further comprising labyrinth means constituted by the two rims (32, 34) and sealing means provided rotatable together with the rotary rim (34) of the labyrinth means and comprising a bottom portion (38a) and a tongue-like portion (38b), wherein the shaft end is sealed by virtue of a contact sealing operation of the sealing means until the motor reaches a predetermined revolution speed, while in a speed range higher than the predetermined revolution speed the shaft end is sealed by virtue of a non-contact sealing operation of the labyrinth means, whereby uniform shaft sealing is effected over a wide range of motor conditions such as from stationary through low speed revolution to high speed revolution conditions by allowing both the contact and non-contact sealing operations to work in combination.