野球バットの打撃性能評価システムの製作とバット支持方法の選択

摘要

野球に限らずボールを打撃するスポーツでは，用具のスイートスポットと呼ばれる領域で打撃すると効率よくボールが打ち返されると表現されるが，種目によってはその位置の定義があいまいで，選手の感覚的な表現である場合も見受けられる。高木は，野球バットのように剛性の高い用具の場合には，打撃中心（撃心）において打撃を行うと用具を握る手に衝撃が伝わりにくく，打撃力が大きいことを説明している。%Many studies on baseball bats have been carried out around the world. Much useful knowledge regarding the development of bats, e.g., coefficient of restitution, trampoline effect etc, have been obtained. However, the effect of the clamping conditions on the hitting performance has not yet been clarified. Therefore, we have developed an evaluation system for the coefficient of restitution on baseball bats using three kinds of clamping devices for the bats, that is, "rigid clamp", "rotat ing-free clamp", and "free support". In this paper, the evaluation system and some examples of the experimental results are reported. We concluded that the differences in the clamping method of metal baseball bats scarcely affected the evaluation results of the coefficient of restitution on hit ting. The rotating-free clamp is well suited to the system from the viewpoint of the simplicity of experimental operation and adequacy of the data.