| 摘要 |
PROBLEM TO BE SOLVED: To provide a bolt which has an aligning function to rectify so as to be coaxial upon engagement with a nut even when the axis line is in inclination and in which dents and the like can hardly occur to a screw thread face. SOLUTION: An integral continuation part of guide having a radius corner part of which radius is reduced gradually in arc-shaped cross section from the outer diameter roughly equal to a screw effective diameter or a major diameter is formed at the tip potion of the bolt, and the screw thread is designed in such manner that the screw end terminates at the middle of the radius corner part of the integral continuation part of guide. The end surface which coincides with a terminus of the radius corner part can be a flat plane approximately perpendicular to the screw axis or can be a predetermined curved surface. When an amount of extension of the integral continuation part in screw shaft direction is denoted by L, and a radius of curvature of the radius corner part is denoted r, then L/r is, for instance, selected as 0.65 to 1.5, and when a pitch of a male screw is indicated as P and the radius of curvature is indicated as r, then r is set within the range of P to 3P, or 1.5P to 2.5P.
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