• Title, Summary, Keyword: Disk brake

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Tribological Characteristics of Brake Disc for Train (철도차량용 제동 디스크의 트라이볼로지 특성 연구)

  • Kim, Sang-Ho;Lee, Hi-Sung
    • Tribology and Lubricants
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    • v.23 no.1
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    • pp.19-28
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    • 2007
  • Mechanical Brake system is inevitable equipment for stability of train and speed of the train. Especially brake disk and brake pads are core parts of mechanical brake system. It was investigated with tribological characteristics of brake discs for train by using lab-scale dynamometer. Gray cast iron disk was most attacked with sintered brake pad. Alloyed steel disk and NCM cast iron disk had suitable friction coefficient, high stability and low disk attack to the sintered brake pad. But at the view of economy, low alloyed cast iron will be most suitable choice.

Experimental Analysis on Brake Squeal Noise Due to Disk Misalignment (디스크 정렬불량에 기인한 브레이크 스퀼소음의 실험해석)

  • 박주표;최연선
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.118-124
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    • 2004
  • To investigate the mechanics of brake squeal noise, the sound and vibration of an actual brake system was measured using a brake dynamometer. The experimental results show that disk run-out due to the misalignment of brake disk varies with brake line pressure and becomes the important factor of brake squeal noise generation. Also, it was confirmed that the frequency of the squeal noise equals to the natural frequency of the disk bending mode.

Influence of Disk Mass with regard to Frictional Characteristics of Brake Disk for Rolling Stock (디스크 질량 변화에 따른 철도차량용 제동디스크의 마찰 특성)

  • Jung, Jong Rok;Ko, Eun Sung;Lee, Hi Sung
    • Tribology and Lubricants
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    • v.30 no.4
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    • pp.240-245
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    • 2014
  • Low alloy heat resistant brake disk and sintered brake pad are applied to mechanical brake system for the speed-up of urban rapid transit. In this research, we analyzed how the frictional characteristics between brake disk and pad are influenced by the disk mass. At a high disk mass, the friction stability was the lower value as a result of the lack of tribofilm formation at the disk surface. Wear rates of friction materials showed the higher value at a low disk mass and wear rates of 10 mm and 15 mm showed the similar level. Average friction coefficient was the lower value at the 10 mm disk thickness and range of variation of average friction coefficient was also the smaller value at the 10 mm disk thickness. However, there were no significant changes in the friction coefficients under any of test conditions. Surface roughness of a disk showed the highest value at the 5 mm disk and surface roughnesses of 10 mm and 15 mm showed the similar level. As a result, friction characteristics of disk mass influenced the friction stability, as well as the wear rate of friction pad and disk, but not the friction coefficient.

A test for friction and wear characteristic of brake disk materials (제동디스크 소재의 마찰-마모특성 시험)

  • Lim, Choong-Hwan;Goo, Byeong-Choon
    • Proceedings of the KSR Conference
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    • pp.1761-1765
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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. It is very important to consider the frictional characteristic because kinetic energy of the vehicle is dissipated as converted thermal energy through friction between disk and brake pad during disk braking. A friction coefficient and wear characteristic are decided from the interrelationship of disk and friction material in the disk brake system. Lab-scale dynamometer test on developed brake disk materials for increasing heat resistance was performed in this study. Each candidate material was tested at various braking speeds and pressures and we obtained the friction coefficient and wear characteristic. And we executed comparative evaluation of the result from the test.

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An Analysis of Plastic Deformation Developed During Interference Fitting of Disk Brake Hub Bolt (디스크 브레이크 허브 볼트의 억지 끼워 맞춤에서 발생하는 소성변형의 해석)

  • Lee, J.S.;Kwak, S.Y.;Kang, S.
    • Transactions of Materials Processing
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    • v.17 no.6
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    • pp.407-411
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    • 2008
  • A brake system in automobile is one of the important parts that directly affect the safety of passengers. Particularly, disk brake module is applied to almost all kinds of automobile brake system due to its remarkable braking power and braking distance. In the disk brake module of an automobile, the bolt for tire wheel is assembled to the disk brake hub by interference fit(bolt pressing process). The process induces small deformation whose range is within tens of ${\mu}m$ and this deformation may cause the runout badness of the whole disk brake module, and even braking problems such as judder or squeal phenomena which makes the loss of braking efficiency. In this study, bolt pressing fit into hub was simulated by $ANSYS^{TM}$, a commercial structure analysis program. Also, the aspect and the cause of hub displacement were analyzed and the solution for decreasing runout of hub was proposed.

Experimental Study of Braking Friction and Wear Characteristics of Disk Brake (디스크 브레이크의 제동마찰 및 마멸특성에 관한 실험적 연구)

  • Kim Chung-Kyun;Lee Boung-Kwan;Kim Han-Goo
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.149-154
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    • 2006
  • This paper presents the braking friction and wears on the rubbing surfaces of a friction pad-disk brake. In this study, four friction disk specimens are sampled from unused and used disks in which are taken from the disk brake system when the friction induced vibration and noise problems have been occurred during a braking period at a running period of 10,000 km, 20,000 km, and 30,000 km in random. The experimental results indicate that the tribological characteristics of an unused disk brake shows equal and stable as a friction coefficient and temperature distributions during a braking friction/wear test period including a total friction mode from the start to running periods. But the used disk brake shows unstable and uneven friction modes between an outside and inside rubbing surfaces of a disk brake in terms of a friction coefficient and wears. This may lead to a friction induced friction vibration and noise problems of a used disk brake.

A Study on the Antiabrasion of the Aircraft Carbon Disk Brake (항공기의 탄소 디스크 브레이크의 내마모성에 관한 연구)

  • Lee, Jang-Hyun;Yum, Hyun-Ho;Hong, Min-Sung
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.21 no.6
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    • pp.968-975
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    • 2012
  • ABS(Anti-skid Brake System) had been developed on purpose of most effect at breaking in limited runway. An aircraft has a large amount of kinetic energy on landing. When the brakes are applied, the kinetic energy of the aircraft is dissipated as heat energy in the brake disks between the tire and the ground. The optimum value of the slip during braking is the value at the maximum coefficient of friction. An anti-skid system should maintain the brake torque at a level corresponding to this optimum value of slip. This system is electric control system for brake control valve at effective control to prevent slip and wheel speed or speed ratio. In this study we measured the thickness of the carbon disk before and after to find its wear and it shows that carbon disk brake has higher stiffness and strength than metal disk at high temperature. In addition, thermal structural stability and appropriate frictional coefficient of the carbon disk brake prove its possible substitution of metal disk brake.

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.

Numerical Prediction of Brake Fluid Temperature Considering Materials of Piston During Braking (제동시 피스톤 소재를 고려한 브레이크 오일 온도의 수치적 예측)

  • 김수태;김진한;김주신
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.445-450
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    • 2004
  • Recently, many studies have been performed and good results have been reported in literature on the prediction of the brake disk temperature. However, study on the brake fluid temperature is rarely found despite of its importance. In this study, brake fluid temperature is predicted according to material property of brake piston. For the analysis, a typical disk-pad brake system is modeled including the brake disk, pad, caliper, piston and brake fluid. Vehicle deceleration, weight distribution by deceleration, disc-pad heat division and the cooling of brake components are considered in the analysis of heat transfer. Unsteady-state temperature distribution are analyzed by using the finite element method and numerical results are compared with the vehicle test data

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Thermo-Elastic Analysis for Chattering Phenomenon of Automotive Disk Brake

  • Cho, Chongdu;Ahn, Sooick
    • Journal of Mechanical Science and Technology
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    • v.15 no.5
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    • pp.569-579
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    • 2001
  • This study investigates the effects of operating conditions on the chattering of an automotive disk brake by experimental and computational methods. Design factors, which cause chattering in automobiles, have attracted great attentions for long time; but they are not well understood yet. For this study, we construct a brake dynamometer for measuring the disk surface temperature during chattering, and propose an efficient hybrid algorithm (combining FFT-FEA and traditional FEA program) for analyzing the thermo-elastic behavior of three-dimensional brake system. We successfully measure the judder in a brake system via the dynamometer and efficiently simulate the contact pressure variation by the hybrid algorithm. The three-dimensional simulation of thermo-mechanical interactions on the automotive brake, showing the transient thermo-elastic instability phenomenon, is presented for the first time in this academic community. We also find from the experimental study that the disk bulk temperature strongly influences the brake chattering in the automotive disk brakes.

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