著者
酒井 英樹
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 (ISSN:21879761)
巻号頁・発行日
vol.83, no.854, pp.17-00064-17-00064, 2017 (Released:2017-10-25)
参考文献数
10

This paper considers ways to increase stability of wheelset hunting. The aim of this study is to introduce formulas which represent the damped natural frequency and its damping. This has been done by analytical and not by numerical calculation. These formulas are functions of mass, creep coefficient and other wheelset parameters. These formulas are obtained with a 2 degree of freedom wheelset model whose radius of gyration of yaw equals to a half of gauge and whose creep coefficient is isotropic, in the first part of this paper. In the second part, based on one of these formulas, ways to increase damping of wheelset hunting are discussed. First, it is shown that a longer wavelength of geometrical hunting is effective in reducing hunting at all vehicle speeds. Secondly, it is shown that at speeds slower than a certain speed, the damping is increased when the ratio of the wheelset mass to the creep coefficient is larger. Further, a symbolic formula for this boundary speed is obtained. Thirdly, if it is assumed that the wheelset mass is proportional to the square of the wheel radius, then at speeds higher than a certain speed, the damping is increased when the wheel radius is larger. Moreover a symbolic formula for this boundary speed is also obtained.
著者
酒井 英樹
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 (ISSN:21879761)
巻号頁・発行日
vol.83, no.854, pp.17-00043-17-00043, 2017 (Released:2017-10-25)
参考文献数
16

Sport riding performance on racing circuits and other locations is seen as an important element in the marketability of motorcycles. In sport riding, some riders start a turn while braking or start acceleration (driving) while turning. Furthermore, the braking aspect of sport riding performance is also critical to accident avoidance performance since it is similar to that of the braking during cornering performance. Consequently, in this paper a fundamental study was carried out to determine methods for improving the cornering limit performance during driving and braking. In the case of four-wheeled vehicles, the G-G diagram is used as a method to indicate the cornering limit performance. In the G-G diagram the longitudinal driving and lateral driving of the vehicle are set as the two axes. Therefore, the first part of this paper proposes a G-G diagram for motorcycles theoretically. In the latter part of this paper, this paper discusses the braking force distribution ratio of front wheel that would maximize the maximum lateral driving, the influence of the normal load distribution ratio of front wheel on the limit cornering property and the influence of the height of the center of gravity on it. From these result, this paper proposes methods for improving the cornering limit performance while braking.
著者
小林 春奈 永村 一雄 酒井 英樹 井川 憲男
出版者
社団法人空気調和・衛生工学会
雑誌
学術講演会論文集
巻号頁・発行日
vol.19, no.2, pp.1063-1066, 2007-08-24

We practiced .thermal measurement outdoors using solar reflective materials that have the potential to suppress heat-island effect. Solar reflectance is calculated by heat balance in one case that samples are horizontal and the other case that samples are inclined so that the angle of incidence is almost normal incidence (about 7degree).We estimate that retroreflective components are 4 to 14 percent for bead-embedded type, 17 to 19 percent for capsule-lens type, and 23 to 30 percent for prism-array type.
著者
渡邉 時夫 酒井 英樹 浦野 研
出版者
全国英語教育学会
雑誌
全国英語教育学会紀要 (ISSN:13448560)
巻号頁・発行日
vol.7, pp.101-110, 1996

The purpose of this paper is to investigate the relationship between the characteristics of teacher talk and the development of spontaneous production ability in the Japanese-speaking children learning English in a kindergarten immersion program. This was done by comparing the teacher talk of two different English-speaking teachers, L and R. These two classes were almost the same in terms of size, children's age, and curriculum. A comparison of the children's L2 development in the two classes revealed that the children in one class produced more creative English, whereas the children in the other used more set phrases. It was hypothesized that this difference may have been due to a difference in quality of L's and R's teacher talk. Analysis of their teacher talk confirmed this hypothesis.
著者
酒井 英樹
出版者
大阪市立大学
雑誌
挑戦的萌芽研究
巻号頁・発行日
2010

照明光源に含まれるわずかな紫外線で励起され,停電後にりん光を発する蓄光材を使った蓄光式誘導標識の発光輝度を向上させる方法を検討した。その結果,視認性確保のために設置されている夜間照明からの漏れ光などによって,弱いながらも常に(停電直前まで)励起状態を保つことが,夜間停電時の発光輝度を高める方法として有効であり,また,照明に用いる光源としては,色温度の高い蛍光灯が適していることを明らかにした。