• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.776-784
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• 2002

We have performed experimental studies for the improvements of pneumatic brake systems of freight trains. Currently, most of the freight trains operated by the Korean National Railroad have either empty-load or diaphragm type brake systems. In this study, appropriate methods that the air pressure characteristics in both type of brake systems are in accordance with each other have been investigated. We have also performed running tests using a 30 car-train set to design optimum capacity of a quick release valve. The test results show that the quick release valve is considerably effective in shortening the release time of the diaphragm type brake system. In the case of a normal brake application, the diaphragm type brake system with the quick release valve reduces the release time to 34% of that of the system without the quick release valve. This release time is almost equivalent to that of the empty-load type brake system. Accordance of braking performance in different types of brake systems in a train set is expected to prevent wheel flats and to reduce maintenance costs.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.170-175
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• 2005

In this study, experimental and theoretical methods were applied to understand brake squeal noise VVVF rolling stock on tracks. Trailer cars needed to payed a particular attention, because they were the major source of brake noise. VVVF rolling stocks for lines no 1 of the subway system in Seoul were used for experimental analyses. In order to study brake squeal noise, a dynamometer test at the S&T Brake, Co., which was a manufacturer of brake pads had performed. For measuring vibration and noise, vibration tests of brake parts (brake lining, brake lining head, back plates, etc.) at the SNUT were executed. Also, vibration tests of disc assembly and lining block at the heavy maintenance shop of the Gunja depot were performed. The modal analyses by using an ANSYS which was one of the CAE commercial program were simulated to know the relationship to the mechanism of brake noise. On the based of the tests and the simulations it was found that specific frequencies of the brake parts affected squeal noise, and improvements for reducing squeal noise were proposed.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.125-132
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• 2007

Within the framework of brake-by-wire technology, this paper presents five types of novel models of electro-mechanical disk brake calipers with self-servo mechanism which provides self-servo effect of boosting a friction force generated between the brake pad and the rotor disk surface. The models have been developed utilizing patent map analysis results of previous invents of electro-mechanical brake calipers. The feasibility of the developed motor-driven brake caliper models have been validated through the dynamic simulation analysis. Among the developed models, the caliper mechanism with separated pressure plate was designed especially in detail and was made as a pilot. The pilot caliper has been installed on the simple test bed constructed with domestic passenger car brake components, and its function and effectiveness have been validated through several types of experimental tests.

• 한국자동차공학회논문집
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• 제8권1호
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• pp.101-109
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• 2000

Occupant protection in the side impact of a car became one of the most important issues of car crashworthiness due to high injury level in a side impact crash. An accurate simulation of the side impact crash is an essential tool for the reduction of development time and cost for side impact safety system. This paper describes a new test methodology that can accurately generate the crash pulses of a vehicle and a door in a very cost-effective manner, and then evaluates the injury values of the dummy for the various sled pulses. This test methodology is simple and easy to approach because the door velocity is controlled by the hydraulic actuator and brake and the seat velocity is only adjusted by the friction force of the hydraulic brake. The superiority of the proposed test methodology is proven by the evaluation of dummy's injury values according to the change of the pressure of the hydraulic brake and by the application as a tool for the development of side airbag.

• 한국산학기술학회논문지
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• 제20권5호
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• pp.56-65
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• 2019

최근 자동차는 안전성, 편리성, 친환경 등의 목적으로 개발되고 있다. 특히, 자동차 안전성에 대한 인식이 중요하게 바뀌고 있다. 이에 따라, ADAS 개발로 인한 안전 시스템들이 등장하였다. 그러나 ADAS의 개발과 시험 평가를 통해 양산 되는 기간은 상당히 오래 걸린다. 따라서 본 논문에서는 ADAS 개발과 시험 평가에 필요한 기간을 단축시키기 위해 브레이크 다이나모미터를 개발 하였다. 또한 개발한 브레이크 다이나모미터는 국제 표준인 JIS D-0210을 만족하며, ADAS의 모드별로 사용자가 시험 조건과 시험 방법을 선택 하여 제동력을 평가할 수 있다. 그리고 개발하는 브레이크 다이나모미터의 신뢰성 검증을 위해 선행 연구에서 제안한 ACC, LKAS, AEB의 시나리오를 사용하였다. 개발한 브레이크 다이나모미터는 시험값과 선행 연구를 통해 제안된 ADAS 모드별 이론식에 의한 계산값을 비교하여 신뢰성을 검증하였다. 또한, 향후에는 ADAS의 실차시험이 불가능한 환경에서 ADAS 모드별 브레이크 부품의 성능 평가가 가능할 것으로 기대 된다.

• International Journal of Automotive Technology
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• 제6권4호
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• pp.391-402
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• 2005

Despite its superior braking performance to conventional vehicles on test tracks, the performance of the ABS-equipped car seems disappointing on real highway. The poor braking performance results from questionable design of the human-machine interface(HMI) of the brake system. Force-displacement relation at the brake pedal has a strong effect on the braking performance. Recently developed brake-by-wire (BBW) system may allow us to tailor the force feel at the brake pedal. This study aims at exploring analytical ways of designing human-machine interface of BBW system. In this paper, mathematical models of brake pedal feel for electro-hydraulic BBW (EH-BBW) system are developed, and the braking motion and the characteristics of the driver's leg action are modeled. Based on the dynamic characteristics of the brake pedal and the driver, two new HMI designs for EH-BBW system are proposed. In the designs, BBW system is modeled as a type of master-slave teleoperator. The effectiveness of the proposed designs is investigated using driving simulation.

• 자동차안전학회지
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• 제9권4호
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• pp.20-25
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• 2017

Dynamo based vehicle inspection device is end of line device for automobile industry. The device is utilized as implementing vehicle functionality inspection such as brake force, cruise control, kick-down acceleration, CAN inspection. As dynamo based inspection device is broadly adopted in automobile industry, the dynamic study is required to verify the vehicle test equipment reliability. This research recommends appropriate dynamic brake force inspection procedure and theoretical background for developed equipment. Dynamic characteristic of brake force implementation to roller is simplified. With simplified characteristics, the indirect brake force measurement strategy is developed and adopted. Comparison of each brake force result, the appropriate brake force inspection criterion is given.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.597-603
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• 2010

Metallic sintered brake pads are often applied to Mid/High Speed Train due to its high strength and thermal characteristics. Because of its imbalance contact between discs and pads can greatly influence the life span, one sided wear, discs attack/crack and threat the safety of the train during operation. In this research, we analyzed pressure/temperature distribution between brake pads and disks. Analyzed data had been verified and modified to conduct further tests of Flexible brake pads with small/full-scale dynamo test. Flexible brake pads were installed to TTX train to conduct further tests to identify the differences between Rigid brake pads and Flexible brake pads. In result, Flexible brake pads showed outstanding disk thermal stability, one sided wear, noise and life of pad than rigid brake pad.

• 한국산학기술학회논문지
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• 제14권7호
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• pp.3158-3163
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• 2013

본 연구에서는 회전속도, 브레이크 압력 제어가 가능한 브레이크 다이나모메타를 제작하여 스퀼 소음 실험을 실시하였다. 브레이크 패드는 각각 $34^{\circ}$, $30^{\circ}$, $26^{\circ}$로 가공하여 패드 각도에 따른 스퀼 발생 조건과 음의 기울기 발생에 따른 스퀼 연관성을 연구 하였다. 각도에 따라 특정한 회전속도와 브레이크 압력에서 스퀼이 발생하였으며, 각도에 상관없이 하모닉 성분을 가지는 특정 주파수 소음을 발견하였다. 햄머링 테스트 및 유한요소해석을 통해서 특정 주파수는 In-plane모드 성격을 갖고 있으며, 패드 각도에 둔감한 모드임을 밝혀냈다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.219-225
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• 2000

This study is to develop a Fe-based disc brake lining with sponge structure for rolling stock of 150km/h train and to concept design with 3 groove type for brake disc reducing hot hair-crack and certainly friction coefficient. The developing brake lining would be to presumption of saving 300 million won during one year