• Title/Summary/Keyword: Disk-Pad Brake

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Finite Element Analysis of Thermal Behaviours of a Disk Brake in High-Speed Trains (고속 전철에서 디스크 브레이크의 열거동에 관한 유한요소해석)

  • 김청균;조승현
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1997.10a
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    • pp.200-210
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    • 1997
  • This paper presents the thermal behaviours of a solid type disk brake for a high-speed train. The thermal behaviours of a brake disk with 50mm thickness shows good performance compared with 45mm thickness of a disk because of a high specific heat capacity and thermal expansion ratio. The FEM results show that the thickness of the d!sk with a same weight of the brake disk should be increased for a good flexibility of the contact thermal problems. Therefore, the ratio between the pad and disk in diameter may be reduced and the thickness of a disk increased.

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Thermal Stress Characteristics of a Disk Pad in High-Speed Trains (고속 전철에서 디스크 패드의 열응력 특성에 관한 연구)

  • 김청균;조승현
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1997.10a
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    • pp.245-255
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    • 1997
  • The thermal characteristics of a disk such as temperature distribution, thermal behaviours and thermal stress during a braking operation has been analyzed for a high-speed train using the finite element method. The maximum stress for a pad loaded against a disk was occurred at the trailing and leading edges of the disk pad at the underlayer-backplate interface. The FEM results indictate that the thermal characterisics of the spot type pad shows good performance compared with those of the flat type pad. Thus, the spot type pad in brake system may be recommended for the high-speed train system.

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A Numerical Study of Thermal Performance in Ventilated Disk Brake (통기식 디스크 브레이크의 방열 성능에 관한 수치적 연구)

  • 김진택;백병준
    • Tribology and Lubricants
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    • v.17 no.5
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    • pp.358-364
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    • 2001
  • Disk brake system transforms a large amount of kinetic energy to thermal energy in a short time. As the size and speed of automotive increases in recent years, the disk brakes absorbs more thermal energy. And this thermal energy can cause an unacceptable braking performance due to the high transient temperature, that is attained at the friction surface of brake disk and pad. Although these high temperatures are one of the biggest problems. In this study, the overall thermal behavior of ventilated disk brake system was investigated by numerical method. The 3-Dimensional unsteady model was simulated by using a general purpose software package “FLUENT” to obtain the temperature distributions of disk and pad. The model includes the more realistic braking method, which repeats braking and release. The effects of several parameters such as the repeated braking, inlet air velocity and thermal conductivity on the temperature distribution were investigated.

A Study on the Temperature Distribution of Disc Brake System Considering the Material Property of the Disc Brake Piston (디스크 브레이크 피스톤 재질을 고려한 브레이크 시스템 온도 분포에 관한 연구)

  • Kim, Soo-Tae;Kim, Jin-Han;Kim, Joo-Shin
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.6
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    • pp.45-51
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    • 2005
  • Braking performance of a vehicle can be significantly affected by the temperature increment in the brake system. Therefore, the important problem in brake system is to reduce the thermal effect by friction heat. Recently, many studies have been performed and good results have been reported on the prediction of the brake disk temperature. However, the study on the pad, piston and brake fluid temperature is rarely found despite of its importance. In this study, the temperature distribution of the disc brake system is studied according to the material properties of brake piston. Vehicle deceleration, weight distribution by deceleration, disc-pad heat division and the cooling of brake components are considered in the analysis of heat transfer. Unsteady state temperature distributions are analyzed by using the finite element method and the numerical results are compared with the experimental data.

Computer Simulations on the Thermal Behaviors of a Friction Pad in High-Speed Train Disk Brakes

  • Kim, Chung Kyun
    • KSTLE International Journal
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    • v.1 no.2
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    • pp.95-100
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    • 2000
  • The thermal behaviors of disk-pad braking models has been analyzed for a high-speed train brake system using the coupled thermal-mechanical analysis technique. The temperature distribution, thermal distortion, and contact stress in the disk-pads contact model have been investigated as functions of the convective heat transfer rate. The FEM results indicate that multiple spot type pads show more stabilized thermal characteristics compared with those of the flat type pads for the increased convective heat transfer rate. The maximum contact stress for a friction pad loaded against a rubbing disk was occurred on the edge of the pad at the disk-pad interface.

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An Experimental Study of Thermoelastic Instability in Automotive Ventilated Disk Brake (통풍식 자동차 디스크 브레이크의 열탄성 불안정성에 관한 실험적 연구)

  • 조병수;백병준;박복춘;김종환;김완두
    • Tribology and Lubricants
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    • v.13 no.4
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    • pp.10-17
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    • 1997
  • The present study describes an experimental investigation of temperature fluctuations associated with thermal instability. Surface temperatures of brake disk and pad were monitered at various locations in a caliper type brake system during drag braking conditions. It was found that the thermal instability appeared in pad more seriously than in disk. The temperatures at various circumferential positions fluctuate synchronously, whereas the center temperature fluctuates with 180 phase difference from the outer and inner radius temperatures. The temperature and amplitude of the temperature perturbations are increased due to the increase of contact area in the center location. It was also found that the thermal instability was dominantly determined by the increase of rotation speed and pressure. And the modification of ventilation path could retard the onset of thermal instability.

The DOE Based Robust Design to Reduce the Brake Squeal Noise (실험계획법에 기반한 브레이크 스퀼 노이즈 저감을 위한 강건 설계)

  • Kwon, Seong-Jin;Kim, Mun-Sung;Lee, Bong-Hyun;Lee, Dong-Won;Bae, Chul-Yong;Kim, Chan-Jung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.2
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    • pp.126-134
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    • 2007
  • Although there has been substantial research on the squeal noise for the automotive brake system, robust design issues with respect to control factors equivalent to design variables in optimization, noise factors due to system uncertainties, and signal factors designed to accommodate a user-adjustable setting still need to be addressed. For the purpose, the robust design applied to the disk brake system has been investigated by DOE (Design of Experiments) based Taguchi analysis with dynamic characteristics. The specific goal of this methodology is to identify a design with linear signal-response relationship, and variability minimization. The finite element models of the disk brake assembly have been constructed, and the squeal noise problems have been solved by complex eigenvalue analysis. As the practical robust design to reduce the brake squeal noise, material properties of pad, disk, and backplate, thickness and geometry of pad are selected as control factors, material properties of pad and disk, and the contact stiffness have been considered as noise factors, and friction coefficient between pad and disk is chosen as a signal factor. Through the DOE based robust design, the signal-to-noise ratio and the sensitivity for each orthogonal array experiment have been analyzed. Also, it has been proved that the proposed robust design is effective and adequate to reduce the brake squeal noise.

Influence of External Air Velocity for Tribological Characteristics between Sintered Friction Material and Disk (외부 공기속도 변화에 따른 소결마찰재와 디스크간 마찰특성)

  • Lee, Jong Seong;Lee, Hi Sung
    • Tribology and Lubricants
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    • v.29 no.1
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    • pp.19-26
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    • 2013
  • Cu-matrix sintered brake pads and low-alloy heat-resistant steel are commonly applied to basic brake systems in high-energy moving machines. In this research, we analyzed the tribological characteristics to determine the influence of the air velocity between the disk and pad. At a low brake pressure with airflow, the friction stability was decreased as a result of the lack of tribofilm formation at the disk surface. However, there were no significant changes in the friction coefficient under any of the test conditions. The wear rates of the friction materials were decreased with an increase in the airflow velocity. As a result, the airflow velocity influenced the friction stability, as well as the wear rate of the friction materials and disk, but not the friction coefficient.

Application of Flexible-Type Sintered Brake Pads (플렉서블 타입 소결 브레이크 패드의 적용 연구)

  • Kim, Soung-Kwon;Kim, Sang-Ho;Kwon, Seok-Jin;Lee, Hi-Sung
    • Tribology and Lubricants
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    • v.27 no.1
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    • pp.19-24
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    • 2011
  • Metallic sintered brake pads are often applied to mid/high speed train due to their high strength and thermal characteristics. 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 high speed 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 wear rate than rigid brake pad.

A Study on Convergence Contact Behavior of Friction Heat and Pad on Disk Brake (디스크 브레이크에서 마찰열과 패드에 작용하는 융합 접촉거동에 관한 연구)

  • Han, Seung-Chul;Lee, Bong-Gu
    • Journal of the Korea Convergence Society
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    • v.9 no.1
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    • pp.283-289
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    • 2018
  • In automotive disc brake systems, frictional heat is not uniformly dispersed for reasons such as heat flux and thermal deformation. The thermoelastic deformation due to the frictional heat affects the contact pressure distribution and the contact load may be concentrated on the contact portion on the the disc brake surface, resulting in thermoelastic instability. In this study, thermal analysis and thermal deformation analysis considering the contact between disk and pad occurred during braking through 3D axial symmetry model with reference to the experimental equation and Kao's analysis method of contact pressure of disk and pad. ANSYS is used to analyze the thermal and elastic instability problems occurring at the contact surface between the disk and the pad, considering both the thermal and mechanical loads. A 3D axisymmetric model with direct contact between the disk and the pad was constructed to more accurately observe the thermal behavior of the disk by observing the frictional surface temperature, thermal deformation and contact thermal stress of the disk.