• Title, Summary, Keyword: 제동 디스크

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Development of Nondestructive System for Detecting the Cracks in KTX Brake Disk Using Rayleigh Wave (Rayleigh Wave를 이용한 KTX 제동 디스크의 균열 검측 시스템 개발)

  • Kim, Min Soo;Yeom, Yun Taek;Park, Jin-Hyun;Song, Sung Jing;Kim, Hak Joon;Kwon, Sung Duck;Lee, Ho Yong
    • Journal of the Korean Society for Nondestructive Testing
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    • v.37 no.1
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    • pp.29-36
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    • 2017
  • Recently, KTX (Korean Train Express) train stoppage accidents were mainly caused by malfunctioning equipment, aging and cracking of railway vehicles, crack breakages of brake disks, and breakages of brake disks. Breakage of brake disk can cause large-scale casualties such as high-speed collision and concern about derailment by hitting lower axle and wheel. Therefore, in this study, a brake disk with solid and ventilation type, which is the brake disk of a KTX train was modeled, and a dynamometer system was constructed to operate the disk. A Rayleigh wave was used to inspect the surface of the brake disk. An ultrasonic inspection module was developed for the brake disk by using a local immersion method due to the difficulty involved in ultrasonic inspection using an existing immersion method. In addition, the surface defects of the brake disk were evaluated using a dynamometer mock-up system and an ultrasonic inspection module of the brake disk.

A Study on the Establishment of Disc Braking Force Pattern to reduce the Wear Mass of Pad (패드 마모량 감소를 위한 디스크 제동력 패턴 설정에 관한 연구)

  • Kim, Seog-Won;Kim, Young-Guk;Kim, Ki-Hwan
    • Proceedings of the KSR Conference
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    • pp.786-791
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    • 2007
  • Korean high speed train(HSR-350x) has adopted a combined electrical and mechanical(friction) braking system. Brake blending control unit(BBCU) controls each brake system to fulfill the required brake performances such as braking distance, deceleration and jerk. Also the braking system should be designed considering the economical management, such as effective use of generated braking energy and the minimum wear of friction materials(a pad and a brake shoe). In this paper, we establish the disc braking force pattern that reduces the wear of pad in the disc braking system by minimizing the variance of the instantaneous disk baking energy during braking time, and compare the wear mass of pad between the conventional disc braking force pattern and the established results.

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An Experimental Study on Braking Thermal Damage of Brake Disk Cover (브레이크 디스크 커버의 제동 열손상에 대한 실험적 연구)

  • Ko, Kwang-Ho;Moon, Byung-Koo
    • Journal of Digital Convergence
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    • v.13 no.11
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    • pp.171-178
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    • 2015
  • The disk cover is installed to protect brake disk and calliper and it's removed right before delivering to customers. The temperature of disk cover was measured driving test vehicles(2000cc, diesel) in this study. The highest temperature measured for the driving test(120km/h-braking(0.3G)-stop-120km/h-braking(0.5G)-stop) was $260{\sim}270^{\circ}C$ in the upper part of the disk cover and the temperature varied considerably around the disk cover. It can be inferred from this temperature distribution around the cover that the major heat transfer from hot disk to cover was through convection. In other words, the hot air generated by braking friction moved up to the upper part of the disk cover. And only the upper area of the disk cover was melted down during this driving test. The thickness of disk cover was increased to 1.0mm from 0.7mm and 1 paper of masking tape was pasted in the upper region of the disk cover. Then the cover endured the heated air formed by braking friction during the driving test.

Development of Brake Disk Materials with Ni-Cr-Mo (Ni-Cr-Mo계 제동디스크 소재 개발)

  • Goo, Byeong-Choon;Lim, Choong-Hwan
    • Journal of the Korean Society for Railway
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    • v.11 no.2
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    • pp.188-194
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    • 2008
  • Brake disks for rolling stock are exposed to thermal fatigue during braking, and thermal cracks occur on surface of disks. Thermal cracks can cause serious accidents, deterioration of braking performance and increase of maintenance cost due to frequent exchange of friction materials. In this study, candidate materials with high-heat resistance were selected by searching the literature. By using cast specimens made of the candidate materials, chemical composition, crystal structure and graphite type were analyzed. In addition, friction coefficient and wear were measured and compared with values for the disk material in service. As a result, it was shown that the NiCrMo has highest tensile strength and lowest friction coefficient and the disk material in service has the most stable friction characteristics.

Analysis of Unstable Vibration Modes due to KTX Brake Disc/Pad Interaction (KTX 제동디스크-패드의 상호작용에 의한 불안정 진동모드 해석)

  • Goo, Byeong Choon
    • Journal of the Korean Society for Railway
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    • v.16 no.4
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    • pp.253-261
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    • 2013
  • According to the measured results of KTX brake squeal noise in this study, high level brake noise occurred in a wide frequency range, 100~18,000Hz. To identify the sources of the brake squeal noise, unstable vibration modes due to brake disc/pad interaction were analyzed under various conditions by the finite element method. Complex eigenvalues for a brake unit with a disc and four pads were obtained. It was found that the real parts of the complex eigenvalues, that is, unstable vibration modes, were closely related to friction coefficients, pressure on the brake cylinders, elastic moduli of the components, and other conditions.

A study of comparative experiment process for heat resistance of brake disk materials (제동디스크 소재의 내열성 비교시험방법 연구)

  • Lim, Choong-Hwan;Goo, Byeong-Choon
    • Proceedings of the KSR Conference
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    • pp.941-947
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    • 2008
  • In the braking of a railroad car, mechanical brake systems using wheel tread and brake disk are applied as well as electrical brake systems by regenerator and rheostat. During disk braking, kinetic energy of the vehicle is converted into thermal energy through friction between disk and brake pad. And it causes high temperature concentration and generates thermal crack on the brake disk surface. In this study, comparative test process for heat-resistance of candidate materials was designed for development of brake disk materials having high heat-resistance. We also verified the efficiency of the process by experiments using conventional brake disk materials.

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A Study on the Temperature Change of Braking Disc and Thermal Conductivity during the Service (철도차량용 제동디스크의 운행중 온도 변화 및 열전도도 측정 연구)

  • Kim, Jae-Hoon;Goo, Byeong-Choon;Suk, Chang-Sung
    • Journal of the Korean Society for Railway
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    • v.10 no.6
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    • pp.665-669
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    • 2007
  • This study investigates the temperature change and thermal conductivity for the braking disc of the railway vehicle due to the types of train and service conditions. The temperature change was measured by non-contact Infrared thermometers. Average temperature was measured between $79.32^{\circ}C$ and $104.46^{\circ}C$ due to types of train and service section. In the same service section, the surface temperatures of Saemaul train were higher than Mugungwha train; the reason might have been the average service speed of Saemaul train (83km/h) was higher than Mugungwha train (107km/h), and the weight was similar 39t (Mugungwha) and 39.3t (Saemaul). But the maximum surface temperature was measured on the Mugungwha train; however the difference was not too big with the maximum temperature of Saemaul train. Also, the disc surface temperatures were changed due to the material of lining; metal and non-asbestos, on the same train and the same service section. In addition. the thermal conductivity was tested the thermal conductivities were increased by the increasing of the temperature. The change is too big between $100^{\circ}C$ and $200^{\circ}C$. But each average value is small. and the mechanical property change is very low. As a result, we conclude that this disc is suitable for usage between $100^{\circ}C$ and $300^{\circ}C$.

A Study on the Fatigue Damage of a Railway Disc Brake Surface Due to Thermal Stress During Braking Using FEM Analysis (FEM을 이용한 철도차량용 제동 디스크의 제동시 답면에서의 열응력에 의한 피로손상에 관한 연구)

  • Joo, Se-Min;Kwon, Yong-Sang;Kim, Ho-Kyung
    • Journal of the Korean Society for Railway
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    • v.12 no.2
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    • pp.212-218
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    • 2009
  • In order to investigate the thermal cracking of the rolling stock brake disc, finite element analysis was conducted on the temperature distribution and thermal stress of the disc during braking. In case of initial vehicle speed of 90, 106, 120km/h, the maximum temperature on the disk surface due to braking was $135.9^{\circ}C,\;157.9^{\circ}C,\;178.7^{\circ}C$, respectively. And, the maximum von-Mises stress at the disc surface was 42.4, 50.3, 57.1MPa at a speed of 90, 105, 120km/h, respectively, indicating that the stress increases with an increment in the speed. Damage fraction due to braking during one year running on the Seoul - Busan line was determined as 14.6%.

Characteristics Evaluation of Light Brake disc and Linning for Railway Vehicle In Terms of Tribology (트라이볼로지 관점에서 철도차량의 경량 제동 디스크와 라이닝의 특성 평가)

  • Kim, Sung-Kwon;Lee, Hi-Sung;Kwon, Seok-Jin;Kwon, Sung-Tae
    • Tribology and Lubricants
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    • v.27 no.2
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    • pp.95-100
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    • 2011
  • The brake disc materials for railway vehicle have been mainly used cast-iron. The brake disc and pad should be light, resist to a thermal crack and absorb enough friction energy. In order to satisfy this requirement, aluminum alloy brake disc for railway vehicle has been newly developed. The aluminum itself has not been considered the friction material for railway vehicle. However, in the case of aluminum composite with dispersed ceramic particles, friction characteristics, resistance to wear and heat are much improved. In the present study, aluminum composite brake disc of 20% ceramic particle and three kinds of organic pads have been tested in dynamometer. The results show that Al MMC brake disc and pad have good friction coefficient and wear rate, and thermal cracks in brake disc have not been initiated. Also, the Al MMC brake disc can be applied to railway vehicle of 150 km/h.

A study on Characteristics of Disc Brake of & Technology of Brake Control System in High Speed Railway (고속차량용 디스크 제동 특성 및 제동제어 방법기술에 대한 연구)

  • Shin Y.J;Choi K.J.;Gwak J.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.393-397
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    • 2005
  • Since the braking system of rolling stock is directly linked to it's safety, ensuring reliability of braking system and evaluation of performance of it are very important. To develope the performance of braking system, it is required advanced technology and gradually various factors in the field test result. This study is designed to analyze the air pressure control about braking force in rolling stock, also, by comparing braking force of high speed railway with that of high speed train. This paper suggests to establish a method of computation of braking force form the air pressure control. And The high speed train researches into patterns of braking system such as the train of speed up and introduction of electric and pneumatic braking system.

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