PROBLEM TO BE SOLVED: To solve such problems that a coil body including a small-diameter distal end and a large-diameter rear end is liable to be formed into a so-called narrow coil body with high rigidity, because the spring constant of the coil body is inversely relates to a coil mean diameter and the spring constant of a small-diameter coil body increases by an outer-diameter difference (similar to a mean-diameter difference of the coil), and that, in such a case, the characteristics of fatigue resistance should be improved with respect to the torsional rotation.SOLUTION: This medical guide wire includes the coil body increasing the number of windings (reducing the coil pitch) without changing the longitudinal length of the small-diameter coil body for suppressing the increase in the spring constant caused by the outer-diameter difference of the coil body and improving the characteristics of fatigue resistance to the repetitive torsional rotation based on a definite relationship between the spring index and a stress correction factor.COPYRIGHT: (C)2012,JPO&INPIT【課題】 コイル体のばね定数はコイル平均径に反比例する為、先端部が小径で後端部が大径から成るコイル体は、外径差(コイル平均径差と同様)に起因して小径のコイル体のばね定数は増大し、いわゆる細くて剛性の高いコイル体となる課題がある。そして又、かかる場合において、ねじり回転操作に対して耐疲労特性を向上させる課題がある。【解決手段】 コイル体の外径差から生ずるばね定数増大分を抑止する為、小径のコイル体の長手方向の長さを変えずに巻き数を増大し(コイルピッチを小さく)又、さらにばね指数と曲げ応力修正係数との一定の関係により、繰り返しねじり回転での耐疲労特性を向上させたコイル体を備えた医療用ガイドワイヤを提供することを特徴とする。【選択図】図1
