| 摘要 |
PURPOSE:To prevent lubricant from going outside of a thrust bearing and maintain a cylinder to rotate normally by forming ventilation grooves which communicate the inner part with the external part of the bearing with each other, thereon as to be straight toward the revolutional center. CONSTITUTION:A thrust bearing 19 which is engaged in the middle hole of a revolutional cylinder 15 and then held on the upper end face of a sleeve 14 with a screw 16 has spiral grooves 20 cut in the middle of the bottom face thereof by the etching means or the like. And ventilation grooves 21 are formed at suitable positions around the spiral grooves 20 as they are directed to the revolutional center of the cylinder to make a straight line, namely, they can be connected to each other through the shortest way. Screw holes 22 in which the screws 16 are inserted are made at the external terminations of the ventilation grooves 21. |
