| 摘要 |
There is provided a universal joint in which a crack is difficult to be produced at a bottom portion of a screw of a bolt for fixing a bearing cup or a bearing holder to a yoke even when excessive large load repeatedly acts and which can withstand to be used over a long period of time under a condition in which a large load of a drive system of a load of a rolling mill or the like acts. In a universal joint of a block type or the like in which a bearing cup 3 for supporting a trunnion 11 of a joint cross 1 through needle-like rollers 2 is fixed to a yoke 4 by a bolt 5 , by constituting the bolt 5 by a bolt subjected to roll forming after a heat treatment, a fiber flow along a shape of a screw is formed, a residual compressive stress is generated right below a surface of a bottom portion of the screw, and an allowable fatigue limit is considerably increased in comparison with that of a bolt by turning process of a background art.
|
