• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2080-2093
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• 2008

대표적으로 높은 운동에너지를 가지는 고속철도와 항공기의 제동장치에 적용되는 금속계 소결마찰재와 내열강 간의 트라이볼로지 특성 연구를 목적으로 각각 2종류의 고속철도용 금속계 마찰재와 항공기용 금속계 마찰재를 Lab-Scale Dynamometer를 이용하여 시험하였다. 그 결과 철도용 금속계 마찰재가 항공기용 마찰재에 비해 높은 마찰계수 및 마찰계수 안정성을 나타내었고, 마모량도 철도용 금속계 마찰재는 항공기용 마찰재에 비해 약 50%수준에 불과하여 본 시험조건에서는 철도용 소결마찰재가 뛰어난 것으로 나타났다. 또한, 동계 마찰재가 철계 마찰재보다 제동시 급격하게 온도가 상승하며, 냉각도 동계 마찰재가 빨리 되지만, 동계 마찰재라도 마찰재의 기지의 량에 따라 달라지는 것으로 나타났다. 마찰재에 따라 마찰면에 형성되는 산화피막의 안정성은 달라지는 것으로 나타났으며, 산화피막은 $Fe_2O_3$와 $Fe_3O_4$계통이며, 마찰재에 따라서 마모메카니즘이 달라지는 것으로 판단된다.

• 한국생산제조학회지
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• 제19권2호
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• pp.211-215
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• 2010

Continuous contraction and expansion of disk brake can be due to friction and temperature difference at repeated sudden braking. As serious vibration at disk is produced, the braking force will be changed ununiformly and braking system can not be stabilized. Temperature and heat flux at disk brake are investigated by structural and thermal analysis in this study. The maximum equivalent stress and displacement are shown respectively at the ventilated hole and the lower part of disk plate. At thermal analysis of initial state, temperature on disk plate is distributed from $95.9^{\circ}C$ to $100^{\circ}C$. The maximum heat flux of $0.0168W/mm^2$ is shown at the inner friction part between disk plate and pad. At thermal analysis of transient state, temperature on disk plate is distributed from $95^{\circ}C$ to $96.5^{\circ}C$ after 100 second. The maximum heat flux of $0.0024W/mm^2$ is also shown at the inner friction part between disk plate and pad. By comparing with initial state, the temperature on disk plate is more uniformly distributed and heat flux is more decreased by 7 times at transient state.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.881-885
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• 2007

The pure electric braking system need to be developed to stop the electric train to zero speed by electricity. This system has advantages like reduction of weight, maintenance cost, noise, and dust generated by disk friction. Therefore, we will study this system for Korean urban transit system.

• 한국철도학회논문집
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• 제10권2호
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• pp.153-160
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• 2007

To start or stop the train safely within the limited traveling distance, it is necessary to guarantee the proper traction or braking force. Presently, most trains are run by the electrical power and have adopted a combined electrical and mechanical(friction) braking system. In order to design a good traction or a brake system, it is essential for designers to predict the traction or brake performance. In this paper, the traction/coasting/braking performances analysis program has been developed and verified by comparing the simulation results with on-line test results of the Korean high speed train(HSR-350); Both results match very well. Consequently, the designers can predict the traction/coasting/braking performances of trains by using the proposed program under various operating conditions.

• 센서학회지
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• 제16권1호
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• pp.68-76
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• 2007

In general, the braking system of a high speed train has an important role for the safety of the train. To stop safely the train at its pre-decided position, it is necessary to properly combine the various brakes. The train has adopted a combined electrical and mechanical (friction) braking systems. In order to design a good brake system, it is essential for designers to predict the brake performance. In this paper, the braking performance analysis program has been developed and verified by comparing the simulation results with the brake test results of HSR-350x; both results match very well. Also, the brake performances of high speed trains can be predicted by using this program under various conditions.

• 제어로봇시스템학회논문지
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• 제4권4호
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• pp.525-533
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• 1998

A conventional contact type brake system which uses a hydraulic system has mny Problems such as time delay response due to pressure build-up, brake pad wear due to contact movement, bulky size, and low braking performance in high speed region. As vehicle speed increases, a more powerful brake system is required to ensure vehicle safety and reliability. In this work, a contactless brake system of an eddy current type is proposed to overcome problems. Optimal torque control which minimizes a braking distance is investigated with a scaled-down model of an eddy current type brake. It is possible to realize optimal torque control when a maximum friction coefficient (or desired slip ratio) corresponding to road condition is maintained. Braking force analysis for a scaled-down model is done theoretically and experimentally compensated. To accomplish optimal torque control of an eddy current type brake system, a sliding mode control technique which is, one of the robust nonlinear control technique is developed. Robustness of the sliding mode controller is verified by investigating the braking performance when friction coefficient is varied. Simulation and experimental results will be presented to show that it has superior performance compared to the conventional method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.676-681
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• 2001

ABS is a safety device, which adds hydraulic system to the existing brake system to prevent wheel from locking, so we can obtain maximum braking force on driving. The hydraulic system to control braking pressure consists of sol-flow type using solenoid valve, flow control valve or consists of sol-sol type using two solenoid valve. In this paper, the hydraulic system in ABS is composed of sol type using a 3port-2position solenoid valve, and vehicle system is composed of 1/4 vehicle model. And slip ratio is controlled using PWM (Pulse-Width-Modulation) control algorithm. Braking friction coefficient and tracking friction coefficient which are described by slip ratio's function have maximum value when slip ratio has its value from 0.1 to 0.3. And slip ratio is controlled constantly in this boundary value even in the variation of road's condition in some boundary.

• 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.

• 유공압시스템학회논문집
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• 제4권1호
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• pp.13-17
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• 2007

The brake gain adaptive wheel slip controller for a vehicle is designed in this paper. The brake gain from braking pressure to braking torque defined by friction coefficient, friction area and effective friction radius is estimated by the adaptive law based on the wheel slip dynamics. And the wheel slip controller is designed based on the estimated brake gain. The robustness of the designed controller is analyzed using Lyapunov function and the convergence of brake gain is verified. Proposed wheel slip controller is verified via CarSim simulation with two kinds of desired wheel slip ratio.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1617-1621
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• 2005

In this study, as a basic research to improve braking efficiency of a ventilated disk brake, we carried out a thermal stress analysis. From analysis result, we knew that a maximum mechanical stress by braking pressure and friction force is applicable to 5 percent of yield strength and has no effect on a fatigue life's decrease for brake disk material. While, a maximum thermal stress by frictonal heat is applicable to 43 percent of yield strength and locates on a friction surface. So, we have found that a thermal stress is the primary factor of crack initiation on a friction surface of disk brake