• Proceedings of the KSR Conference
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• 2006.11b
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• pp.294-299
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• 2006

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. When the disc brake is applied in the high speed region, the wear of pad is increased rapidly. In this paper, we discuss the optimized patterns of the disc brake force from the view point of braking energy.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.385-390
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• 1999

In this paper, we investigated the wear rate, braking temperature and stopping distance of the composite brake shoe for diesel locomotive in the field test. The wear rate and braking temperature of the composite brake shoe would rather than cast iron. Also, the stopping distance of composite brake shoe is 450m at 100km/h. This result of field test shown that the density distribution of the composite brake shoe influence on wear rate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1555-1556
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• 2011

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.125-130
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• 2001

It is vary importance that stopping distance for the freight train and need to design parameter of the brake force and friction coefficient. Acoording to the brake force between shoe and wheel less than the adhesion between wheel and rail. Because of vary difference between empty and weight car of 0∼500kN, this solution was made to application for variable loaded brake system. When the V=110km/h. the emergency stopping distance of freight train is about 700m, so this study was considered on the two condition, one of the increse brake force and to be different of the increse friction coefficient on the brake shoe. It was useful increse friction coefficient. Result of study, analyze effect of the brake shoe on the brake force of the freight car and high friction coefficient were proposed. To do this, ${\mu}$=0.155${\pm}$10% when S=600m on the V=110km/h of the train, 2 groove of friction surface on the temperature distribution were considered.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.103-108
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• 2003

Among welded structure bogies in use for high speed freight car, a part of bogies manufactured in 1999 and 2000 have found problems that failure occurs in its end beam. In case of a freight car a difference of weight between empty and loading conditions are worse than in case of a passenger car. Moreover its brake system is tread brake without second suspension system. A failure of end beam is supposed to be due to loading by brake rather than vertical loading by freight. This failure can make brake system useless and may be a cause of derailment in the worst case. In this study, in order to be proved the cause of failure and to solve the problem it is described that we have measured load history acted on end beam and set up the procedures.

• Proceedings of the KSR Conference
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• 2005.11a
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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.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.377-382
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• 2003

In tread braking of freight cars, braking force is produced by the friction between the wheel and the braking shoe. Friction coefficients such as the brake power, weight variation and brake shoe types should be sensitively treated as the design parameters. The conditions of the car, empty and weighted, should also be taken into consideration in brake force design and the control of brake force has some limitations in terms of the brake system design so that the brake materials selection should be considered as important measures to solve that difficulties. Friction characteristics of brake materials should remain within the range of maximum and minimum value and the friction performance should remain stable regardless of braking time and temperature. This study presented an experimental evaluation method to secure optimum braking performance by keeping safe braking effect and braking distance by the friction coefficient of the brake shoe of the freight cars.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.697-698
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• 2008

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1909-1915
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• 2008

The brake systems of the rolling stocks are generally consisted of electrical and mechanical brake systems. Because of its inherent structure of the each brake system, the electrical brake system is mainly used at the high speed range while the mechanical brake system is used at the relatively lower speed range. It is desirable for the rolling stocks to apply the entire electrical brake system. However, since the brake force from electric brake system is not enough to stop the rolling stock within the legal stop distance. Therefore, the mechanical brake system is indispensable to rolling stocks. In general, the vast majority of the world trains are equipped with mechanical braking systems which use compressed air as the force to push block on to wheels or pads on to discs. These mechanical systems are known as air brake or pneumatic brakes. For the air brake system, basically huge scale air compressor is equipped and the long pipe line is complexively connected. Since mass of these air brake components, it is difficult to be a light weight equipment and the long pipe line raise the maintenance problem. In order to overcome these problems of air brake system, the hydraulic brake system is proposed in this research. The hydraulic brake system makes the whole weight of brake equipment be light and large braking force can be applied. Therefore, in this research, the validity and advantages of applying the hydraulic brake system are reviewed.

• Proceedings of the KSR Conference
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• 2010.06a
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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.