著者

高見 創

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B編 (ISSN:18848346)

巻号頁・発行日

vol.79, no.803, pp.1254-1263, 2013 (Released:2013-07-25)

参考文献数

8

被引用文献数

1 18

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There is a strong demand for improving brake system performance of Japanese Shinkansen which is a high speed railway to shorten the stopping distance at the time of an emergency such as a huge earthquake. An emergency brake for conventional train is a wheel disk brake system that is affected by rail tread surface condition (dry or wet condition), because of using friction (adhesion) between a wheel and rail. In order to achieve a high deceleration at the time of over 300 km/h, another complementary brake system guaranteed a stable braking force without the friction is required. In addition, it has to be a lightweight and small equipment space so that a passenger cabin capacity may not be affected. In this study, we discussed a small-sized aerodynamic brake system using an air drag panel. From the computational fluid dynamics using turbulent flow model and the wind tunnel experiment, the suitable shape of air drag panel, arrangement and an opening-and-closing mechanism of the panel were developed. In addition, a full-scale prototype aerodynamic brake device was designed and manufactured. Its aerodynamic characteristics were examined on a large wind tunnel with high Reynolds number. It was proven that the target braking force can be obtained with the small-sized aerodynamic brake placed into a thick turbulent boundary layer around the train at a running speed of 300 km/h.

著者

高見 創

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.86, no.881, pp.19-00295, 2020 (Released:2020-01-25)

参考文献数

16

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To shorten the stopping distance of the high-speed trains in case of emergency such as a huge earthquake, the author developed the small-size and light-weight aerodynamic braking device. The device increases an aerodynamic drag force of a train to achieve a high deceleration at the range of over 350 km/h without a friction between rail and wheel. The device is as miniaturized as possible in order to be installed flexibly on the train, whereby many devices with small-size drag panels are appropriately arranged throughout the train roof to obtain higher drag force. A pair of drag panels rotating around a horizontal axis which are connected by the gear can be actuated by the traveling wind without a large-size actuator. The full-scale prototype aerodynamic braking device is designed and manufactured. To examine its aerodynamic characteristics, one or two prototypes are tested on a wind tunnel facility at a maximum flow speed of 400 km/h (111 m/s). It was proven that the response time of motion from the folding position to the braking position took only 0.39 s, and the device could produce the aerodynamic drag of 2.3 kN per one unit at 400 km/h. Detached-eddy simulation (DES) is used to study the flow around a train roof with a large number of devices. The rate of change of the drag coefficient for devices with the staggered arrangement which aims to improve a total drag force of a train is compared against the standard parallel arrangement at U = 360 km/h. The staggered arrangement could increase the total drag coefficients 10.3 percent as compared to the standard parallel arrangement.

著者

高見 創

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

pp.19-00295, (Released:2019-12-16)

参考文献数

16

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To shorten the stopping distance of the high-speed trains in case of emergency such as a huge earthquake, the author developed the small-size and light-weight aerodynamic braking device. The device increases an aerodynamic drag force of a train to achieve a high deceleration at the range of over 350 km/h without a friction between rail and wheel. The device is as miniaturized as possible in order to be installed flexibly on the train, whereby many devices with small-size drag panels are appropriately arranged throughout the train roof to obtain higher drag force. A pair of drag panels rotating around a horizontal axis which are connected by the gear can be actuated by the traveling wind without a large-size actuator. The full-scale prototype aerodynamic braking device is designed and manufactured. To examine its aerodynamic characteristics, one or two prototypes are tested on a wind tunnel facility at a maximum flow speed of 400 km/h (111 m/s). It was proven that the response time of motion from the folding position to the braking position took only 0.39 s, and the device could produce the aerodynamic drag of 2.3 kN per one unit at 400 km/h. Detached-eddy simulation (DES) is used to study the flow around a train roof with a large number of devices. The rate of change of the drag coefficient for devices with the staggered arrangement which aims to improve a total drag force of a train is compared against the standard parallel arrangement at U = 360 km/h. The staggered arrangement could increase the total drag coefficients 10.3 percent as compared to the standard parallel arrangement.

著者

高見 創 嵯峨 信一

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.82, no.844, pp.16-00337, 2016 (Released:2016-12-25)

参考文献数

13

被引用文献数

1

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Brake squeals phenomena of the disc brake system for railroad cars were reproduced and were investigated in the test stands using a full-size brake rotor, a wheel, a floating caliper and a brake pad. Brake squeals of the disc-brake apparatus occurred at a low speed of 20 km/h or less, and the magnitude of brake squeals increased as the average braking force increases until it was saturated. Frequencies of the brake squeals exceeding the background noise of the test facility are 800 Hz, 2 kHz, 3.2 kHz, and 6.3 kHz. The largest squeal of 6.3 kHz was radiated from the leading side of the pad and the rotor, and coupled vibrations between the rotor and the pad were attributed to the self-excited vibration induced by the dry friction. To measure the vibrations of the rotating disc at the time of brake squeals, vibration measuring systems operating by wireless power supply were installed in the rotating axle. As a result, one-third octave band analysis of brake squeals at 6.3 kHz and at 3.2 kHz approximately coincides with the vibration of both the rotor and pad, and the coupled vibration tends to grow larger in the high friction coefficient range. Furthermore, these frequencies agree well with the natural frequency of the rotor examined using the scanning laser doppler vibrometer. The mode shapes and amplitude of rotor vibrations at the time of brake squeals are significantly affected by the number of bolts and their fastening positions to the wheel.