| 摘要 |
PURPOSE:To prevent the bending fatigue by forming a projecting stripe part in the circumferential direction onto the first top part side inclined surface inside the first bottom part and preventing the concentration of a large strain in the second bottom part. CONSTITUTION:A projecting stripe part 2 is formed onto the first top part 9 side inclined surface of the inside of the first bottom part 8. Therefore, when a driving shaft 11 performs the crossing movement in theta=30 deg., the second bottom part 7 is pushed by the projecting stripe part 2 in the contraction part of a bellows part 6, and shafts to the small-diameter ring part 5 side. Therefore, in the second bottom part 7, the concentration of strain is not generated. Further, even if the crossing angle becomes large, the second bottom part 7 is pushed by the projecting stripe part 2, and shifts to the small-diameter ring part 5 side, and the concentration of the strain in the second bottom part 7 is not generated, and bending fatigue can be prevented. |
