| 摘要 |
PROBLEM TO BE SOLVED: To make, in a negative-pressure type booster, an attachment part in the side of attachment destination member of a tie rod bolt long while preventing a forging apparatus of the tie rod bolt from enlarging its size.SOLUTION: In an attachment part (a rear end part 33) of a tie rod bolt 30 of a negative-pressure type booster in the side of an attachment destination member, there are formed an under-screw part 33d, an extension part 33c and a caulking part 33b in this order from the tip (rear end). A under-screw diameter that is the outer diameter of the under-screw part 33d, an extension part diameter that is the outer diameter of the extension part 33c, and a caulking part diameter that is the outer diameter of the caulking part 33b are set in a manner being larger in this order from the smallest to the largest.SELECTED DRAWING: Figure 2 |
