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  • Title/Summary/Keyword: Disk-Pad Brake

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Study on Development of Flexible Pad for High Speed Train Disk Brake (고속철도 디스크 브레이크의 유연 패드 개발에 대한 연구)

  • Lee, Min-Gyu;Kim, Joo-Yong;Kim, Jae-Min;Yang, Young-Min;Kim, Sang-Ho;Cho, Chong-Du
    • Journal of the Korean Society for Railway
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    • v.14 no.2
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    • pp.100-108
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    • 2011
  • This paper investigates the structural stability and reliability on improving performance of flexible brake pad used in high speed train. To this end, an improved model of flexible pad was obtained through structural analysis. Brake pad specimens were subjected to modal, stroke and endurance tests to examine the dynamic characteristics and mechanical stability. The hot spot generation with increasing rotational speed was observed on chassis dynamometer equipment and then the structurally uniform contact between the disc and pad was achieved. The temperature distribution of flexible pad was measured using the infrared camcorder. Hence, the proposed flexible pad showed the better structural stability and thermal energy emission.

Numerical Study of Miro-Contact Surface Induced Hot Spots in Friction Brakes (마찰식 브레이크의 미세 접촉면에 발생된 적열점 현상의 수치적 연구)

  • 김청균;조승현
    • Tribology and Lubricants
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    • v.19 no.5
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    • pp.268-273
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    • 2003
  • This paper presents hot spot behaviors on the rubbing surface of disk-pad type brake by using coupled thermal-mechanical analysis technique. The height of micro-asperity on the rubbing surface is usually 2∼3 μm in practical disk brakes. Non-uniform micro-contacts between the disk and the rigid friction pads lead to high local temperature distributions, which may cause the material degradation, and develop hot spots, thermal cracks, and brake system failure at the end for a braking period. The friction temperatures on the rubbing surface of disk brakes in which are strongly related to the hot spot and thermal related wears are rapidly concentrated on the micro-contact asperities during braking. The computed FEM results show that the contact stress, friction induced temperature and thermal strain are highly concentrated on the rubbing micro-contact asperities even though the braking speed and force are small during the braking period. This hot spot may directly produce the slippage and various thermal wears on the brake-rubbing surface.

A Study of Frictional Contact Vibration Influence on Hot Spot in Automotive Disk Brake (디스크 브레이크에서 접촉 마찰 진동이 열섬에 미치는 영향 연구)

  • Cho, Ho-Joon;Kim, Myoung-Gu;Cho, Chong-Du
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.1
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    • pp.154-161
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    • 2007
  • Hot spot phenomenon that occurs, during judder vibration, is locally concentrated heat due to friction between brake disk and pad. It is important to understand the reason behind hot spot phenomenon, for reduction of judder vibration. In this experimental study, experiments were performed in accordance with rotation speed of brake disk, pressure of master cylinder and pad length for achieving different aspects of hot spot phenomenon. Temperature distribution of hot spot was obtained by using the infrared camera. As the hot spot occurred, vibration was measured and frequency analysis was performed. Finite element analysis of thermal deformation of disk was performed by using temperature distribution that was achieved by experimental results. And mode shapes of disk was analyzed by finite element analysis and compared with experimental results. It was observed that the excitation frequency band of frictional contact and frictional force mainly affects the hot spot phenomenon.

The Invention of New Electro-Mechanical Brake Calipers Utilizing Patent Analysis Results (특허분석 결과를 활용한 새로운 전기기계 브레이크의 발명)

  • Han, In-Hwan;Park, Sang-Il
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.1
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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.

The Origin and Effect of Hot Spot Phenomena on Judder Vibration in Automotive Disk Brake (디스크 브레이크에서 열섬 현상이 발생되는 원인과 저더 진동에 미치는 영향)

  • Cho, Ho-Joon;Cho, Chong-Du;Kim, Myoung-Gu;Maeng, Ju-Won;Lee, Jae-Han
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.213-218
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    • 2006
  • Hot spot phenomenon is caused by non-uniform contact area between brake pad and disk frequent braking. Brake disk deformed by locally concentrated heat increases magnitude of frictional vibration. And this deformation can highly influence the judder vibration. In this experimental study, vibration and hot spot was measured in accordance with rotation of disk and pressure of master cylinder for finding the factors that causes hot spot phenomena. For comparing hot spot aspects with mode shapes of disk, mode shapes were measured by conducting modal test, and analyzed by using finite element analysis. Relation between hot spot phenomenon, and mode shape, pressure of master cylinder and rotation speed of disk respectively, was achieved by hot spot measurement and frequency analysis.

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The Origin and Effect of Hot Spot Phenomena on Judder Vibration in Automotive Disk Brake (디스코 브레이크에서 열섬 현상이 발생되는 원인과 저더진동에 미치는 영향)

  • Cho, Chong-Du;Kim, Myoung-Gu;Cho, Ho-Joon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.8 s.113
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    • pp.886-892
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    • 2006
  • Hot spot phenomenon is caused by non-uniform contact area between brake pad and disk frequent braking. Brake disk deformed by locally concentrated heat increases magnitude of frictional vibration. And this deformation can highly influence the judder vibration. In this experimental study, vibration and hot spot was measured in accordance with rotation of disk and pressure of master cylinder for finding the factors that causes hot spot phenomena. For comparing hot spot aspects with mode shapes of disk, mode shapes were measured by conducting modal test, and analyzed by using finite element analysis. Relation between hot spot phenomenon, and mode shape, pressure of master cylinder and rotation speed of disk respectively, was achieved by hot spot measurement and frequency analysis.

Development of the Sintered Friction Material for the High Speed Railway (고속철도 차량용 소결 마찰재료 개발)

  • Kim Ki-Youl;Kim Sang-Ho;Kim Yu-Shin;Lee Beom-Joo;Kim Seog-Won
    • Proceedings of the KSR Conference
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    • 2004.06a
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    • pp.315-321
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    • 2004
  • Dawin Friction Corp. has been advanced sintered brake pad for Korean concept high speed train (so called G7 train) with KRRI, You Jin and Rotem without the assistance of foreign company. In the course of development, the evaluation of our and foreign disk pads was performed by lab scale dynamometer and full scale dynamometer. As the result of dynamo test, it is shown that our developed brake disk is equal or superior to those of foreign companies in many respects, for example, wear resistance, noise, etc. The new brake pad which is developed through 'post G7-project' is equipped with G7 train and is under many tests without any problems at the present moment.

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Design for Yaw Brake System in Wind Turbine (풍력발전기 요 브레이크 시스템의 설계)

  • Park, Jin-Hwan;Park, Sang-Shin;Yoon, Yong-Ik;Yoo, Chang-Hee;Hwang, Jung-Gyu
    • Tribology and Lubricants
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    • v.27 no.4
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    • pp.204-208
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    • 2011
  • Yaw brakes are used in wind turbines to control the orientation of blades to be perpendicular to the wind. These devices are very important machine elements because they are closely related to the overall efficiency of wind turbines. One unit of yaw brakes is composed of a friction pad and a caliper. In this study, a tangential force between the friction pad and the disk is calculated when the brake is acting in 750 kW wind turbine. Then, stress distribution and the deformation of the caliper are calculated using a finite element analysis. An experimental equipment is also developed to verify the exactness of calculated results. The analytical and experimental results are presented and discussed.

Three-dimensional Simulation of Hot spots in Disk Brakes (디스크 브레이크의 적열점에 관한 3차원 시뮬레이션)

  • 이일권;조승현;김청균
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.06a
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    • pp.211-218
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    • 2000
  • Hot spot behaviors on the disk-pad contact surface during a braking operation have been analyzed for a ventilated disk brake using the finite element method. Hot spots which were studied using a coupled thermal-mechanical analysis technique are influenced by all of the mechanical, thermal, elastic and plastic processes that are involved in braking cycles, but their temperature gradients are most affected by rubbing speeds, braking forces, and design parameters between the disk and the pad. Undesirable hot spots that are generated by local thermoelastic instabilities are intended to be removed by optimized design parameters and material properties. In this study, a three-dimensional numerical method for the demonstration of hot spot behaviors has been applied to the rubbing surfaces between the disk and the pad.

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A Study of Thermal Behaviors on the Effect of Aspect Ratio of Ventilation Hole in Disk Brake (디스크 브레이크의 방열구 형상비에 따른 열적 거동에 관한 연구)

  • 김진택
    • Tribology and Lubricants
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    • v.18 no.6
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    • pp.384-388
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    • 2002
  • The adequate design of a passenger car braking system, which is directly related to the safety of a car, is very important since the safety is an essential design parameter of a car to keep men and car from the damage. The thermal behaviors of the ventilated disk has been investigated based on the air cooling effects during repeat braking operations. In this study, the 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 aspect ratio of ventilated hole on the heat dissipation was investigated.