• 제목/요약/키워드: brake pad

검색결과 190건 처리시간 0.026초

고속전철용 디스크-패드 브레이크의 동적거동 특성에 관한 유한요소해석 (Finite Element Analysis on the Dynamic Behaviors of a Disk-Pad Brake in High-Speed Trains)

  • 김청균;조승현
    • Tribology and Lubricants
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    • 제16권2호
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    • pp.7-7
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    • 2000
  • Using a coupled thermal-mechanical analysis, the dynamic distortion of the ventilated disk brakes has been presented for a high-speed train. The offset ratio between the maximum and minimum values of the thermal distortions has been analyzed as a function of a braking number. The computed FEM results show that the offset rations in radial direction are much greater than those of circumferentially distorted components. This means that the axial distortions in radial direction may dominantly produce thermally caused wears and cracks at the rubbing surfaces.

고속전철용 디스크-패드 브레이크의 동적거동 특성에 관한 유한요소해석 (Finite Element Analysis on the Dynamic Behaviors of a Disk-Pad Brake in High-Speed Trains)

  • 김청균;조승현
    • Tribology and Lubricants
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    • 제16권2호
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    • pp.99-105
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    • 2000
  • Using a coupled thermal-mechanical analysis, the dynamic distortion of the ventilated disk brakes has been presented for a high-speed train. The offset ratio between the maximum and minimum values of the thermal distortions has been analyzed as a function of a braking number. The computed FEM results show that the offset ratios in radial direction are much greater than those of circumferentially distorted components. This means that the axial distortions in radial direction may dominantly produce thermally caused wears and cracks at the rubbing surfaces.

디스크 브레이크 마찰표면의 적열점에 관한 수치적 연구 (Numerical Study on the Hot Spots of Friction Surface in Disk Brakes)

  • 김청균;조승현
    • 대한기계학회논문집A
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    • 제28권11호
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    • pp.1692-1696
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    • 2004
  • This paper presents the thermally induced hot spot characteristics of rubbing surface in the friction pad disk brake. During the braking period, the rubbing surface with irregular asperities that are strongly engaged in rough surface, wear, and deformed surface due to a friction heating may produce an irregular distorted geometry of the disk surface. The tribological interactions between the disk and the pads are unstable if the contact stress is severe, in which the irregularity develops the contact pressure distribution, leading eventually to localized contact, high temperature and formation of hot spots. The computed results of contact spots that are simulated using a coupled thermal-mechanical analysis present sinusoidal distortions and localized extrusions of the disk surface, which are strongly related to a hot spot in the practical disk brake.

디스크 브레이크와 패드의 접촉을 고려한 벤틸레이티드 디스크 브레이크의 열적거동에 관한 연구 (Thermal Behavior of Ventilated Disc Brakes Considering Contact Between Disc and Pad)

  • 마정범;이봉구
    • 한국생산제조학회지
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    • 제23권3호
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    • pp.259-265
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    • 2014
  • When the brakes of a vehicle are applied, large amounts of heat are generated on the surfaces of the brake discs owing to friction between the discs and the brake pads. A high temperature gradient on the disc surfaces leads to thermal deformation and severe disc abrasion. Ultimately, the thermal deformation and disc wear give rise to a thermal judder phenomenon, which has a major effect on the stability of the vehicle. To investigate and propose a solution to these problems, thermoelastic instabilities under applied thermal and mechanical loads were analyzed using the commercial finite element package ANSYS by considering the contact surfaces between the discs and pads. Direct-contact three-dimensional finite elements between the discs and pads were applied to investigate the disc friction temperature, thermal deformation, and contact stress so that the thermal judder phenomenon on the surface of the disc could be predicted.

휠 슬립 제어를 위한 타이어와 노면 사이의 타이어 제동력 및 노면 마찰계수 추정 (Estimation of Tire Braking Force and Road Friction Coefficient Between Tire and Road Surface For Wheel Slip Control)

  • 홍대건;허건수;윤팔주;황인용
    • 대한기계학회논문집A
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    • 제28권5호
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    • pp.517-523
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    • 2004
  • Recently, wheel slip controllers with controlling the wheel slip directly has been studied using the brake-by-wire actuator. The wheel slip controller is able to control the braking force more accurately and can be adapted to various different vehicles more easily than the conventional ABS systems. The wheel slip controller requires the information about the tire braking force and road condition in order to achieve the control performance. In this paper, the tire braking forces are estimated considering the variation of the friction between brake pad and disk due to aging of the brake, moisture on the contact area or heating. In addition, the road friction coefficient is estimated without using tire models. The estimated performance of tire braking forces and the road friction coefficient is evaluated in simulations.

MAXIMUM BRAKING FORCE CONTROL UTILIZING THE ESTIMATED BRAKING FORCE

  • Hong, D.;Hwang, I.;SunWoo, M.;Huh, K.
    • International Journal of Automotive Technology
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    • 제8권2호
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    • pp.211-217
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    • 2007
  • The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS (Anti-lock Brake System) systems. In realizing the wheel slip control systems, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance and stability enhancement. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm is proposed for maximizing the braking force. An adaptive law is formulated to estimate the braking force in real-time. The wheel slip controller is designed based on the Lyapunov stability theory considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm searches for the optimal target slip value based on the estimated braking force. The performance of the proposed wheel slip control system is verified in HILS (Hardware-In-the-Loop Simulator) experiments and demonstrates the effectiveness of the wheel slip control in various road conditions.

한국형고속열차의 디스크-패드 마찰계수 측정에 관한 연구 (A Study on the Measurement of Disc-Pad Friction Coefficient for HSR-350x)

  • 김영국;박찬경;박태원;김석원
    • 한국철도학회논문집
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    • 제9권6호
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    • pp.677-681
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    • 2006
  • In general, the braking system of high speed train has an important role for the safety of the train. To stop the train safely at its pre-decided position, it is necessary to combine the various brakes properly. The Korean high speed train (HSR-350x) has adopted a combined electrical and mechanical (friction) braking system. In this study, the measuring method that can obtain the disc braking forces and friction coefficient between disc and pad during on-line test of HSR-350x has been suggested and verified through the comparison of the results obtained from this method and those of the results of the dynamo-tests.

유한요소법에 의한 드럼 브레이크의 열응력 해석 (Thermal Stress Analysis of Drums Brakes by Finite Element Method)

  • 구병춘;서정원
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집A
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    • pp.831-836
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    • 2001
  • In the case of axisymmetric thermal analysis of drum brakes, the distribution of frictional heat produced on the interface and temperature difference between mating frictional faces are very interesting problems to computational researchers. In this paper, heat conduction from the interface to the pad and the drum was modeled by using a thin interface element, so artificial division of the generated frictional heat between pad and drum is not necessary. Temperature difference between mating frictional faces is successfully modeled by using the interface element. The influence of some parameters on tile thermal stress was checked. The analysis was performed by ABAQUS/Standard code.

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마찰에너지율을 이용한 타이어 제동거리 예측 (Braking Distance Estimation using Frictional Energy Rate)

  • 전도형;최주형;조진래;김기전;우종식
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.519-524
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    • 2004
  • This study is concerned with the braking distance estimation using frictional energy rate. First, steady state rolling analysis is performed, and using this result, the braking distance is estimated. Dynamic rolling analysis during entire braking time period is impratical, so that this study divides the vehicle velocity by 10km/h to reduce the analysis time. The multiplication of the slip rate and the shear stress provides the frictional energy rate. Using frictional energy rate, total braking distance is estimated, In addition, ABS(Anti-lock Brake System) is considered, and two type of slip ratios are compared, One is 15% slip ratio for the ABS condition, and the other is 100% slip ratio which leads lo the almost same braking distance as the elementary kinematic theory. A slip ratio is controlled by angular velocity in ABAQUS/Explicit, A 15% slip ratio gives the real vehicle's braking distance when the frictional energy occurred al disk pad is included. Disk pad's frictional energy rate is calculated by the theoretical approach.

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