| 摘要 |
PURPOSE:To sharply increase the life of a bearing by supporting a load in the radial direction during operation only by the journal bearings of upper and lower bearing parts and providing a supporting member which supports the weight of a rotary body only while not operating. CONSTITUTION:On the upper bearing part of a motor, a ball bearing 200 which supports the weight of a rotary body only while stopping, and a journal bearing 300 are provided on the upper end of a rotary shaft 17 while a journal bearing 400 is provided on the lower bearing part. During operation (left side in the figure; right side shows during stopping), fluid is discharged due to the rotation of an impeller 19, thrust acts upwardly in the direction of the rotary shaft 17 and the rotary body parts as a whole are slightly floated up, causing the outer race 202 of the ball bearing 200 to be separated from the top surface 301 of the recessed part of the journal bearing 300 creating a gap (b), without applying any load. Part of said fluid is introduced from the arrow direction C to a sliding surface between the journal bearings 300, 400 to carry out lubrication. Thus, all the load in the radial direction can be supported by said bearings 300, 400, while there is no wear due to solid lubrication, enabling a stable operation for a long time.
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