著者

小林 弘二 京極 啓史 中原 綱光

出版者

日本スポーツ産業学会

雑誌

スポーツ産業学研究 (ISSN:13430688)

巻号頁・発行日

vol.7, no.2, pp.19-32, 1997-09-30 (Released:2010-07-27)

参考文献数

7

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This paper describes the dynamics of Japanese bows and arrows. In "kyudo" (Japanese archery), archers twist the grip at the moment of shooting, to avoid the "archers' paradox" which is a change of trajectory of the arrow caused by the structure of the bow and the arrow. To investigate the relation between the trajectory of an arrow and the twisting force on the grip, we proposed a dynamic model simplifying three rigid limbs and two elastic hinge. And we made an experimental apparatus that can give a force to twist the grip, and performed a shooting experiment. We measured with a strain gauge the twisting force on the grip, the tension of the string, bending moment at the center of arrow, and the compressive force of the neck. After that, we performed a computer simulation with the model we suggested and compared its result with the result of the experiment. As a result of comparison we proved that the tendency of computer simulation is consistent with the experiment. Then using this model, we investigated the relation between the twisting force and the trajectory of an arrow. As a result of simulation, twisting force is shown to be specially important during the term from taking a stance to the beginning of the shooting.

著者

久米 洋道 京極 啓史 中原 綱光

出版者

一般社団法人日本機械学会

雑誌

年次大会講演論文集 : JSME annual meeting

巻号頁・発行日

vol.2000, no.4, pp.351-352, 2000-07-31

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Friction characteristics between cam and follower are numerically calculated using an approximate method. The model is based on partial EHL theory which consists of a film thickness formula[Ref.1] modified from Pan-Hamrock's formula[Ref.2]) considering surface roughness and the mean contact pressure-compliance relationship (GW model[Ref.3]). The effects of non-Newtonian behavior of lubricant and surface temperature rise are taken into account for the calculation of friction force. The result of this approximate method is compared with the previous study (Tanaka et al. [Ref.4]) which solved simultaneously Reynolds equation, elasticity equation, etc. and the experimental results obtained by a made apparatus similar to the system. The validity of approximate method is also examined, for mainly the effects of amplitude and directional properties of surface roughness.