著者

末岡 淳男 劉 孝宏 白水 健次 江村 篤裕 中野 寛

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.70, no.689, pp.38-45, 2004-01-25 (Released:2011-03-04)

参考文献数

5

被引用文献数

4 3

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This paper deals with the occurrence mechanism of the squeal and chatter phenomena generated in a bicycle disk brake and their countermeasures. From the results by bench test apparatus, it was made clear that the squeal is in-plane vibration in the direction of rotor surface with frequency 1kHz caused by the frictional characteristics with negative slope with respect to the relative velocity generated in the vibration system including brake components and spokes, and the chatter is another frictional vibration with frequency 500Hz in which the squeal occurring in the in-plane direction of rotor and the out-of-plane vibration of rotor due to Coulomb friction are superimposed through the internal resonance relation caused by temperature increase of rotor during braking. The measures for squeal and chatter were taken on spokes and hub, and the validity was confirmed by using bench test apparatus.

著者

井上 卓見 末岡 淳男

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C編 (ISSN:03875024)

巻号頁・発行日

vol.66, no.644, pp.1074-1081, 2000

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The authors present a new step-by-step integration scheme by utilizing the cardinal B-splines. The new method organizes conventional implicit methods such as Newmark-β method and Wilson-θ method and so on, and provides a simple computation procedure so that the step-by-step integration can be carried out efficiently. In addition, when we analyze a nonlinear system with discontinuity the computational acuuracy can be improved by the approximate detection of the points of discontinuity by making good use of the two-scale relation. In this paper, we formulate an algorithm of a time historical response analysis of a straight-line beam structure as an elementary example of multi-degree of freedom system besides a simple single degree of freedom system. The cardinal B-splines used here are only the ones of orders 3 and 4 but the other cardinal B-splines are also available for step-by-step integration in the same way.

著者

中江 貴志 劉 孝宏 末岡 淳男

出版者

日本学術会議 「機械工学委員会・土木工学・建築学委員会合同IUTAM分科会」

雑誌

理論応用力学講演会 講演論文集

巻号頁・発行日

vol.57, pp.180-180, 2008

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本報で取り扱う自転車用ディスクブレーキは乾性摩擦に起因するロータ面内方向主体の振動である1000Hzの「鳴き」と,ロータ高温時にのみ発生する乾性摩擦に起因するロータ面内方向の連成振動とクーロン摩擦に起因するロータ面外振動が重畳された非線形自励振動現象である500Hzの「ビビリ」が発生する.この「ビビリ」は鳴き振動数のちょうど半分の振動数で振動しており,ロータ面内方向と面外方向の振動モードが振動数比2:1で内部共振関係にあることを意味する.本報では,ブレーキユニットのうち重要な要素であるスポーク,ロータ,ハブ,キャリパのみを解析対象に簡単なモデルを構築し線形計算によりこれら2つの現象を再現する.

著者

松崎 健一郎 劉 孝宏 末岡 淳男 塚本 恵三 眞方山 航平

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.852, pp.17-00155-17-00155, 2017 (Released:2017-08-25)

参考文献数

7

被引用文献数

1

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Reaming is a finishing process to be performed in order to improve the accuracy of the prepared hole drilled. In this process, a chatter vibration often occurs and the drilled hole is deformed in a polygonal shape. This polygonal deformation phenomenon becomes a problem in quality control of products, because of decrease in the precision of the borehole. Although a countermeasure by irregular tooth spacing is proposed and the prevention effect is confirmed, the mechanism has not been clarified yet. In this paper, the generating mechanism of the polygonal deformation is considered to be a self-excited vibration caused by time delay. A simple analytical model is proposed, and the stability of the self-excited vibration is analyzed numerically. The numerical result agrees well with the actual phenomenon qualitatively. Furthermore, the effect of irregular tooth spacing on the stability of the self-excited vibration is evaluated numerically.

著者

劉 孝宏 末岡 淳男 白水 健次 江村 篤裕 中野 寛

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.70, no.689, pp.30-37, 2004-01-25 (Released:2011-03-04)

参考文献数

11

被引用文献数

2 2

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This paper deals experimentally with the squeal and chatter phenomena generated in mountain bike disk brakes. First, the authors performed the traveling test using actual bicycle on downhill road in a mountain. As the results, there are two kinds of frictional self-excited vibrations in the bicycle disk brakes called by squeal with frequency of 1 kHz and by chatter with frequency of 500 Hz. In order to regenerate the squeal and the chatter, a bench test apparatus by actual bicycle was set up and their characteristics were experimentally examined. By using the bench test apparatus, it was made clear that their frequencies were independent of temperature of pad and rotating speed of rotor, and the chatter was generated in a certain limited region of high temperature though the squeal occurred in arbitrary temperature region of pad.

著者

吉武 裕 末岡 淳男 森山 智樹 山崎 正則

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.66, no.646, pp.1785-1792, 2000-06-25

被引用文献数

6

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This paper deals with the quenching problem of self-excited vibrations by using a device composed of a Hula-Hoop and a generator. This device is also additionally able to generate electricity. The Runge-Kutta-Gill method is applied to the numerical analysis of a Rayleigh's type self-excited system with the device. The solutions obtained are divided into two main categories ; periodic solutions and chaos accompanied by Hula-Hoop's vibration and rotation. An optimum approach for quenching the self-excited vibration was discussed. As a result, it was clarified that for the optimum design of the device there existed a certain relation among the moment of inertia, the mass of Hula-Hoop and the capacity of generator, and the vibration at that time was chaos as in the impact damper which we analyzed before. The condition of maximum generation of electricity was not equal to that of minimum vibration amplitude of the self-excited system. An experiment was performed to quench vortex-induced vibration and to generate electricity by using the device. The experimental results agreed well qualitatively with those from the numerical computational analysis.

著者

中野 寛 末岡 淳男 劉 孝宏 家藤 英世 折居 利昭 中江 貴志

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.72, no.720, pp.2373-2381, 2006-08-25 (Released:2011-03-04)

参考文献数

8

被引用文献数

2 4

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This paper deals with the occurrence mechanism of the squeal phenomena generated in a new type of bicycle disk brake unit and its countermeasure experimentally and analytically. It was made clear that squeal was in-plane vibration in the direction of disk surface with frequency 650 Hz caused by frictional characteristics with negative slope with respect to the relative velocity, and was generated in the vibration system including brake unit and spokes, in the same manner of old type of disk brake unit. The countermeasure against squeal by using a dynamic absorber was conducted. The simple analytical model of the bicycle disk brake system was set up. Some features of squeal phenomena and the optimal design of dynamic absorber for quenching squeal were made clear analytically and it was confirmed that the analytical results agreed well with the experimental ones.

著者

末岡 淳男 井上 卓見 松崎 健一郎 高山 佳久 劉 孝宏

出版者

九州大学

雑誌

萌芽研究

巻号頁・発行日

2003

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高速増殖炉ヘリカル伝熱管深傷プローブの振動によるセンサノイズの原因とその対策を,モックアップによる実験と数値シュミレーションによって明らかにした.得られた結果は以下のようにまとめられる.(1)ECT(Eddy current testing)プローブを静止させて蒸発管内で圧縮空気だけを流しても,プローブには振動は発生しないが,プローブの圧送時には振動を生じる,すなわち,プローブの振動の原因は流体力ではなく,蒸発管内壁とプローブにあるフロートとの間の摩擦と考えられる.(2)ECTプローブの挿入過程では,挿入距離の増大に伴ってプローブの振動が激しくなる.ヘリカル管の中間部を過ぎると,約20HZの卓越した振動数で振動し,それに伴ってRF(Remote field)ノイズも大きくなる.そのとき,ECTプローブは軸および径方向に連成振動をしており,RFセンサは尺取り虫的な動きをする.一方,引戻過程では,卓越した振動数を持つ振動は発生せず,振動レベル,RFノイズとも挿入過程よりも低い.(3)挿入時には,ECTプローブはヘリカル伝熱管の内径側に張り付き,引戻時には,逆に外径側に張り付くように圧送される.したがって,挿入時および引戻時で,ECTプローブにはそれぞれ張力および圧縮力が作用している.(4)ECTプローブの搬送速度を高くするほど,圧送用の空気量を多くするほど,ヘリカル直径を小さくするほど,ECTプローブの軸および径方向振動もRFノイズも大きくなる.(5)ECTプローブの径方向の振動は,先端にいくほど大きい.また,RFノイズは励磁センサと検出センサの径方向相対振動の大きさと相関があるが,軸方向振動とは相関がない.(6)RFノイズを最小化するためには,6m以上で,曲げ剛性が比較的低い先導プローブを持つECTプローブを構成することである.(7)伝達影響係数法を適用して,大規模なプローブ列を対象とした流体による搬送力を含む摩擦振動を解析した結果,モックアップの実験結果とほぼ同様な数値計算結果を得ることができた.

著者

津田 吉広 田村 英之 末岡 淳男 松岡 寛憲

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.60, no.578, pp.3300-3307, 1994-10-25

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The characteristic which the Duffing oscillator with a softening spring property under harmonically stimulating force presents in the main resonant region has been investigated numerically. With regard to the structure which the system exhibits in this region, there exists another branch which appears due to bifurcation from the resonant branch at a certain frequency, in addition to the resonant and nonresonant branches. It has been clarified that many kinds of periodic solutions exist in the region between this new branch and the resonant one. Furthermore, besides the traditional harmonic solutions, i. e., resonant and nonresonant solutions, it has been shown that another harmonic solution appears, although it is unstable. This unstable solution enables us to reasonably explain the constitution of attractors in this resonant region. Chaotic phenomena, which appear due to period doubling bifurcation also exist.