| 摘要 |
PURPOSE:To shorten a thrust shaft by shaping the spirally grooved lower part of the thrust shaft in the discoidal form whose diameter is larger than that of the upper part thereof. CONSTITUTION:A thrust shaft 1 on the lower part of which spiral grooves 4 are cut is shaped in the discoidal form, the diameter thereof being larger than that of the upper part of the thrust shaft 1. When the thrust shaft 1 turns, the spiral grooves 4 collect lubricant in the film form between the bottom face of the thrust shaft 1 and the bottom face of a thrust bearing 5 to raise the bottom face of the thrust shaft 1, producing an oil gap 9 therebetween. When the thrust shaft 1 turns, the circumferential speed of the spiral grooves on the discoidal lower part becomes high. Because of this reason, if the width of the spiral grooves in the longitudinal direction of the thrust shaft is short, the thrust shaft may be floated up from the thrust bearing. |
