• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.131-138
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• 2001

This paper describes the result of endurance test of the brake system of the Korean EMU on the Sangju test track. The purpose of the test is to prove the endurance of brake system. Test conditions are more severe than actual operation on the commercial line. As of October, test result is good without severe problems. 100,000km of test operation will be continued by the end of this year to check the endurance of the brake system.

• 자동차안전학회지
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• 제12권2호
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• pp.47-55
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• 2020

In this case study, the brake line failure of air over hydraulic(AOH) brake system is described. AOH brake system is applied to commercial vehicles between 5 to 8 tons. It consists of a hydraulic system using compressed air and operates the air master to form hydraulic pressure to transfer braking power to the wheels. When the brake lines of the system applied to vehicles with high load capacity are damaged, the braking force of one shaft is lost, and the braking distance increases rapidly, leading to a big accident. Failure of the brake line occurs due to various causes such as road surface fragmentation, corrosion of the line, and aged deterioration of air brake hose. The braking force could be decreased even when a very small break in the form of a pin-hole occurs. However, it is difficult to find a part where the thickness of the line is thin due to stone pecking or corrosion generated in the pin-hole formed on the brake line located under the lower part of the vehicle by the sensory evaluation or the conventional braking force test. Accordingly, it is necessary to analyze the condition and cause of the failure of the brake line more precisely when the accident investigation of the heavy vehicles, and also to examine the necessity of the advanced test for the aged brake line.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1943-1952
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• 2011

철도차량의 제동장치는 움직이는 차량의 운동에너지를 다른 형태의 에너지로 일부 또는 전부를 변환시켜 속도를 감소시키거나 멈추게 한다. 이를 위해서는 정확한 제동력이 요구되며 특히 대향 운송 수단인 철도차량에서는 매우 중요한 장치로 여겨지고 있다. 이러한 제동력 산출의 기준이 되는 값이 바로 제동거리이다. 철도차량이 제작되어 영업운전에 투입되기 전 수십 차례의 제동거리 측정시험을 통해 그 차량에 맞는 제동력이 결정된다. 제동거리는 차량과 레일 조건에 따라 변화하며 그 요소로는 차량의 중량, 제동 직전의 속도, 제동디스크 온도 및 레일 상면의 상태 등이 있다. 본 연구는 이러한 요소들에 어떻게 제동거리에 영향을 미치지는 실제 시험결과를 통해 고찰하고자 한다.

• 한국소음진동공학회논문집
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• 제23권6호
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• pp.485-494
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• 2013

This paper deals with experimental evaluation methods for high speed judder on the brake-caliper system. Firstly, two types of brake caliper systems due to the wheel vibration was evaluated. Secondly, the high-speed judder of the brake was also investigated using the subjective rating evaluation in the high-speed road test. These experimental evaluations were carried out by changing the materials of brake pad and the specifications of the brake-corner module. Based upon the test results, a new specification of the brake pad, $15{\times}5$ vertical chamfer, was proposed. The new brake pad showed 3 points, 60 %, improvement in the subjective-rating evaluation comparing with conventional one. Besides, we need to decide properly with judder characteristic of pad material and have to carefully take into consideration other design parameters; caliper, disc, and the braking performance, durability, squeal noise.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.228-230
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• 2006

While trains perform a complete precision stopping control at stop point, it is essential to keep better commuters comfort in prompt. Because a train's brake force tends to increase a brake effort in a low speed and a low brake effort, a brake force in motor cars must be increased to keep better passenger comfort, to control the special braking qua1ities and to prevent the impact of the automatic coupler rather than trailer's, Rail cars must have a special braking process for the train stopping control. In the train stop mode, the train stopping control is designed to start at 20km/h. It starts by Dynamic brake blending, and then finally stops by only the friction. If these process are not exactly activated, the train may fail a complete precision stop. In this report, it studied the electric and friction brake processing during the precious stopping control. To achieve exact test results, the speed reference has to be reduced the calculated difference. In the precision stopping control. the ways of the keeping brake force in motor car was analyzed and some solutions of controling air pressure was brought up by means of direct test in main line, This study was based on line 5 in Seoul Metropolitan subway.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.148-156
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• 2001

Brake judder, one of low Sequency vibrations in brake system is determined by the excitation of Brake Torque Variation (BTV). The largest contributor to BTV is disc thickness variation. In this study, the static loads of brake torque at Suspension Mounting Points (SW) are obtained by the quasi-static analysis using DADS. The dynamic loads with frequency of BTV at SW are derived from correlation between forced vibration analysis with static loads and brake test results. And the accelerations at steering wheel were analyzed by forced vibration analysis with dynamic loads using commercial finite element program MSC/NASTRAN so that vibration characteristics of vehicle due to brake judder were investigated. Reliability of analysis results was verified through comparing the brake test results. Also, a parametric study with natural frequencies of frame, such as the 1st torsional mode and 1st bending mode, was conducted to reduce vibration amplitudes. As a result we could detect frame natural frequency conditions to improve vibration characteristics and obtained the frame model to reduce vibration amplitude.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.593-598
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• 2000

Experimental study is conducted to clarify the pneumatic characteristics of brake system for freight train. Empty-load and diaphragm brake systems are mainly installed in the freight trains owned by KNR(Korean National Railroad). Experimental train set is composed of sixteen freight train and one diesel locomotive that are now in use. From the experimental results, in case of commercial brake, empty-load brake system responds to the brake command more slowly than the diaphragm brake system. But, in case of release command, the response time of diaphragm brake system is shorter than that of empty-load one. In the emergency brake test, the decreasing rate of brake pipe pressure of tenth car is almost same that of decreasing rate of commercial brake service.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.483-488
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• 2004

The inter-laboratory comparison test which is demanded on the authorized test of ISO/IEC 17025 is the program to guarantee the confidence of test result. This paper, as a part of the inter-laboratory comparison test between South Korea and China, is refered to the characteristic of friction coefficient of disk brake lining for rolling stock according to disk type. Brake tests were carried out under constant brake force and operating sequence by using dynamo-tester according to disk and disk lining types. To establishing the confidence of test result, we calculated A type uncertainty about friction coefficient and investigated the factors about the variation of friction coefficient.

• 한국항행학회논문지
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• 제27권6호
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• pp.821-827
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• 2023

본 연구에서는 국내 및 미국의 항공기 기술기준과 기술표준품 표준서를 분석하여 수송류 항공기용 금속계 제동패드의 비행시험 인증을 위한 합치성 증명 시 요구되는 다이나모시험절차를 도출하였다. 제동장치의 설계개조는 중대한 변경으로 분류되어 부가형식증명 및 부품등제작증명이 동시에 요구된다. 다이나모시험 항목은 미국의 제동장치 기술표준품 표준서인 TSO-C135a 규정에 따라 비행시험의 적합성을 판단하는 기준으로 비행시험 시 요구되는 주요 시험항목 중 설계착륙-정지 시험, 가속-정지 시험 및 최대 하중상태의 착륙-정지 시험을 선정하였다. 다이나모시험 조건은 항공기 제조사가 제공하는 주요 사양에 따라 정해지며, 제동패드의 조건, 감속도 및 시험횟수 등은 TSO-C135a 규정에 따라 정의하였다.

• 자동차안전학회지
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• 제14권3호
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• pp.41-47
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• 2022

Composite material is recently very important material for eco-friendly vehicles because of its excellent mechanical property and lightweight effect. So, many research results have been recently published for developing the composite material to apply vehicles. In this paper, new brake system is presented using composite material to response this situation. And advantages in terms of performance compared to competitive company will be discussed in depth to verify superiorities of the new composite brake. To do so, composite brake systems which have the same size as the competitive company to the same vehicle is applied. And superiorities through a variety of test results are presented. First, normal braking performances are compared with competitive company through braking effect, heat capacity and friction test, Second, circuit driving and high speed fade test are also verified with competitive company to confirm harsh braking performances for the new composite brake system. Finally, the effects of applying the composite brake to automobile industry like electric car are analyzed.