• Title/Summary/Keyword: Brake squeal noise

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Analysis of Natural Frequencies and Squeal Noise of KTX Brake Unit (KTX 제동장치의 고유진동수와 스퀼소음 분석)

  • Goo, ByeongChoon;Na, InKyun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.12
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    • pp.954-961
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    • 2014
  • Brake squeal noise of KTX is very uncomfortable to passengers and workers in stations. A lot of study has been conducted to inquire into the mechanism of the squeal noise. But understanding of the brake squeal noise is still challenging. In this study, we developed a full-scale tester equipped with a KTX mechanical brake unit. And we measured the vibrational characteristics of each component of the brake unit and compared them with frequency response functions of brake squeal noise measured also in the tester. It was found that the brake squeal noise was more closely related to the vibrational characteristics of the brake pads and hangers in friction condition than those of free components.

Study on the break squeal noise of rolling stock on tracks and improvements for reducing squeal noise (전동차 브레이크 스퀼소음 현상 및 개선에 대한 연구)

  • Chung, Su-Young;Kim, Seong-Keol
    • 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.

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A Study for the Improvement of the Brake Squeal Noise (제동시 브레이크 소음 개선에 관한 연구)

  • 김동우;이희욱
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.6
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    • pp.223-228
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    • 1996
  • The frequency of the brake squeal noise can be changed during braking, and this frequency shifting is due to variation of braking deceleration rate. The natural frequency of the brake system also shifted according to deceleration rate. It makes difficult to treat this problem. This paper shows an experimental study on the brake squeal noise having main frequencies of about 450~500Hz. And it shows how to improve the brake squeal noise problem.

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Experimental Analysis on Brake Squeal Noise Due to Disk Misalignment (디스크 정렬불량에 기인한 브레이크 스퀼소음의 실험해석)

  • 박주표;최연선
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.118-124
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    • 2004
  • To investigate the mechanics of brake squeal noise, the sound and vibration of an actual brake system was measured using a brake dynamometer. The experimental results show that disk run-out due to the misalignment of brake disk varies with brake line pressure and becomes the important factor of brake squeal noise generation. Also, it was confirmed that the frequency of the squeal noise equals to the natural frequency of the disk bending mode.

An Experimental Study on the Squeal Noise Generation due to Dynamic Instability of Brake Pad (브레이크 패드의 동적 불안정성에 따른 스퀼 소음 발생 원인의 실험적 연구)

  • Cho, Sangwoon;Lim, Byoungduk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.5
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    • pp.520-526
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    • 2016
  • Squeal noise is a typical brake noise that is annoying to both passengers and pedestrians. Its frequency range is fairly wide from 1 kHz to 18 kHz, which can be distressful to people. The brake squeal noise occurs due to various mechanisms, such as the mode coupling of the brake system, self-excited vibration, unstable wear, and others. In this study, several parameters involved in the generation of a squeal noise are investigated experimentally by using a brake noise dynamometer. The speed, caliper pressure, torque, and friction coefficient are measured as functions of time on the dynamometer. The contact pressure and temperature distributions of the disc and the pad are also measured by using a thermal imaging camera and a pressure mapping system. As a result of the simultaneous measurement of the friction coefficient and squeal amplitude as functions of the velocity, it is found that the onset of the squeal may be predicted from the ${\mu}-v$ curve. It is also found that a non-uniform contact pressure causes instability and, in turn, a squeal. Based on the analysis results, design modifications of the pad are suggested for improved noise characteristics.

An Experimental Study on the Squeal Noise Generated in Friction Surface of Disk Brake (디스크 브레이크의 마찰면에서 발생되는 스퀼소음에 관한 실험적 연구)

  • 이해철;이원평;차경옥
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.26-31
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    • 2000
  • There are various noises generated by friction. Among the rest, eliminating squeal noise generated during braking is an important task for the improvement of vehicle passengers' comfort. The parameters affecting brake squeal noise are the material properties of the braking pad, the dynamic properties of the brake parts and the dimensions of the brake assembly etc. Also, the squeal noise changes its inherent form with the normal load and sliding speed. In this study, the characteristics of brake squeal noise generated by friction is analyzed experimentally. The experiment focused on the analysis of friction self-excited vibration and squeal noise level. Friction self-excited vibration is caused by the dry friction between pads and rotor, and occurs as a function of their relative sliding speeds. And Friction self-excited vibration is raised the brake squeal noise.

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A Study on the Squeal Noise Instability Analysis on Caliper Brake (캘리퍼 브레이크 스퀼 소음의 불안정성 해석에 관한 연구)

  • Lee, Junghwan;Kim, Seonghwan
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.11
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    • pp.957-965
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    • 2013
  • This paper deals with analytical methods for low frequency and high frequency brake squeal noise on brake-rear caliper. In order to improve low frequency and high frequency squeal noise, we take survey caliper bracket shape parameters and housing shape parameters. Besides, using the combination of bracket and housing parameter were surveyed. Thus, using the combination of bracket Alt_05 and housing Alt_45 specifications, instability analysis and brake dynamo test were carried out. Based upon the two models, low and high frequency squeal noise of base model were improved. But, for 6.0 kHz frequency noise, which is not improved, it needs to additionally study on instability analysis and combination of the other brake components.

Experimental Study of Wet-Brake Squeal Noise in a Forklift (지게차용 습식 브레이크 스퀼소음의 특성 및 측정실험에 관한 연구)

  • Kim, Tae-Jong;Jeong, Weui-Bong;Kim, Moon-Saeng;Kim, Young-Hyun;Joo, Won-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.10
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    • pp.996-1002
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    • 2009
  • Elimination of squeal noise occurred during brake application is an important task for the improvement of comforts in an industrial forklift. In this paper, a test rig was developed which was possible for testing of brake noise and an experimental measurement on squeal noise was performed. The causes of the brake noise are identified by experimenting how the factors such as automatic transmission fluid and rpm of drive axle affect the squeal. In order to identify the squeal characteristics, the signal analyses for noise are performed by using frequency spectrums. Also, brake test using a forklift was carried out to confirm the reliability of test results by using a test rig comparing with the occurrence of squeal noise. Experimental results showed that the tendencies of occurrence of squeal noise are well agreed at two test methods by using the test rig and forklift.

A Study on the Squeal Noise generated by Self-excited Vibration in Friction surface (마찰면에서 자여 진동에 의해 발생되는 스퀼 소음에 관한 연구)

  • 이해철
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.10a
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    • pp.90-96
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    • 1998
  • There are various noises generated by friction. Among the rest, eliminating squeal noise generated during braking is an important task for the improvement of vehicle passengers' comfort. The parameters affecting brake squeal noise are the material properties of the braking pad, the dynamic properties of the brake parts and the dimensions of the brake assemble etc. Also, the squeal noise changes its inherent form(i.e. its sound pressure level and its frequency) with the normal load and sliding speed. In this study, the characteristics of brake squeal noise generated by friction is analyzed experimentally. The experiment focused on the analysis of friction self-excited vibrationand squeal noise level. Friction self-excited vibration is caused by the dry friction between pads and rotor, and occurs as a function of their relative sliding speeds. And Friction self-excited vibration is raised the brake squeal noise.

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The Prediction of Brake Corner Module Squeal Noise Using Participation Factor Analysis (기여도 분석법을 이용한 자동차 브레이크 시스템의 스퀼 소음 예측)

  • Lee, Jong-Ghi;Lim, Hyun-Seok;Kim, Hee-Yong;Baek, Jae-Wook
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.10
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    • pp.1074-1080
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    • 2009
  • A method for determining the geometric stability characteristics of a brake corner module (BCM) is presented. Since disc brake "squeal" noise typically occurs at unstable resonant frequencies of a system, the likelihood of disc brake squeal for a particular design can be determined. Finite element methods are used to derive complex eigenvalue for a brake corner module. Some unstable modes calculated by finite element methods correspond to squeal noise data. Through kinetic energy participation analysis for each part of BCM, we can efficiently predict squeal noise data.