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Analysis of Low-Frequency Squeal in Automotive Disc Brake by Optimizing Groove and Caliper Shapes
Kim, Cheol,Kwon, Yonghwan,Kim, Dongwon Korean Society for Precision Engineering 2018 International Journal of Precision Engineering and Vol.19 No.4
A low-frequency squeal that occurs due to the coupling phenomena of various vibrational modes in a disc brake system may cause annoyance to passengers. In an effort to remove the irritating low-frequency squeal of the disc brake, we carried out complex eigenvalue analysis and investigated the contribution ratio of each part to the occurrence of squealing. To this end, we developed a reliable and accurate finite element (FE) model of each brake part and compared it to the model test results. Throughout the complex eigenvalue analysis for the FE models, all unstable modes and corresponding frequencies in the brake system were calculated. The dominant parts that contributed largely to the squealing of the brake system were also elicited by the component contribution factor (CCF) analysis. Parts such as the disc, carrier, pad, and knuckle, were determined as large contributors to squealing. To reduce squealing, the tie-bar shape and the groove shape around the disc hub were optimized by FE-based shape optimization. A new disc with an optimal groove and a new tie-bar were manufactured, and dynamo squeal tests were conducted for a comparison to the numerical prediction. A fairly good correlation was observed between the experimental and numerical analysis results.
이기연(Ghiyoun Lee),이광호(Kwangho Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Squeal noise which is the majority of brake noise is divided into low frequency squeal and high frequency squeal. Generally, the low frequency squealing mechanism is a rotor axial direction mode that couples the pads, rotor and other components; while higher frequency squeal mainly exhibits a rotor tangential mode. In this paper, the low frequency squeal is pointed and some examples are exhibited to reduce noise by means of mode decoupling.
브레이크 패드의 동적 불안정성에 따른 스퀼 소음 발생 원인의 실험적 연구
조상운(Sangwoon Cho),임병덕(Byoungduk Lim) 한국자동차공학회 2016 한국 자동차공학회논문집 Vol.24 No.5
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 μ - 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.
강재영(Jaeyoung Kang) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
This paper reviews the recent comprehensive models and results for disc brake squeal. The previous brake squeal analysis based on FEM overlooked many essential factors physically existing on the squeal phenomena. Most of all, the friction model between a rotating disc and two stationary pads was oversimplified. Also, the previous studies were narrowly focused on mode-coupling, which did not provide the complete explanation for the squeal mechanisms. In order to overcome the limitation, the comprehensively generalized brake squeal model and the corresponding FEM are introduced in terms of the disc rotation effect, the in-plane vibration modes, the detailed squeal mechanisms, nonlinear squeal behavior, FE modeling methodology, and so on.
문경호,유원희,김재철 한국철도학회 2003 한국철도학회논문집 Vol.6 No.3
When a rail vehicle transverses tight curves, it often emits an intense, high-pitched squeal. This squeal has always been noticed as one of the most disturbing noise sources of railway systems. At present, we cannot predict squeal noise that is influenced by a large number of dependent parameters. In this study, we performed structural analysis to find out the frequency of the wheel and measured squeal noise at Seoul subway. We also tested reduction effectiveness of squeal noise through rail lubricator.
주행속도와 제동력 변화에 의한 디스크 브레이크의 스퀼 소음에 미치는 영향
심동혁(DongHyouk Shim),김대열(DaeYeol Kim),고석훈(SeokHoon Ko) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Brake noise is classified according to frequency territory: judder, groan and squeal. Squeal noise of disk brake is a noise and self excited vibration with frequency of 1~10Khz caused by the friction force between the disk and the pad of the automobile. Passengers in a vehicle feel uncomfortable. It causes unstable characteristic to the brake system when you try to stop the vehicle. Thus this study aims to find in which conditions the vehicles are stable during the braking hour and find ways to decrease a squeal noise and the vibration by measuring various factors including squeal noise and self excited vibration between the pad and disk brake system during the braking hour. From the result the countermeasure for a squeal noise and a vibration decrease is established. Also the analyzed data is found to be useful and can be applied to the actual brake model.
주행속도와 제동력의 변화에 의한 디스크 브레이크의 스퀼 소음에 미치는 영향
김정훈(J. H. Kim),김경훈(K. H. Kim),최명진(M. J. Choi) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월
Brake noise is classified according to frequency territory: judder, groan and squeal. Squeal noise of disk brake is a noise and self excited vibration with frequency of 1~10Khz caused by the friction force between the disk and the pad of the automobile. Passengers in a vehicle feel uncomfortable. It causes unstable characteristic to the brake system when you try to stop the vehicle. Thus this study aims to find in which conditions the vehicles are stable during the braking hour and find ways to decrease a squeal noise and the vibration by measuring various factors including squeal noise and self excited vibration between the pad and disk brake system during the braking hour. From the result the countermeasure for a squeal noise and a vibration decrease is established. Also the analyzed data is found to be useful and can be applied to the actual brake model.
Brake Squeal Noise를 유발하는 Brake Contact Interface와 Rotor의 In-Plane Modes에 관한 연구
이종화(Jongwha Lee),조호준(Hojoon Cho),이재한(Jaehan Lee),최원석(Wonseok Choe),김세혁(Sehyuk Kim),정명구(Myoungkoo Chung),오정용(Jungyong Oh),김인동(Indong Kim) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
For many years, brake noise has been one of the top automotive brake warranty issues, and many studies have been conducted to reduce the squeal phenomenon by improving the rotor-pad contact interface or by decoupling modes inducing squeals. This research investigates brake contact interface and rotor in-plane modes which generate brake squeal noise and conduct a robust correlation between CAE and Test by using methods such as the 3D laser vibrometry ODS and modal mapping. This paper considers the different brake contact interfaces affecting low frequency brake squeal and introduce an effective way of reducing the problem by improving one of the brake secondary contacts. On the discussion with the rotor in-plane mode, importance of rotor radial mode on inducing squeal issues and noise risks being introduced by rigid in-plane modes on assembly restraint conditions are topics that are often being left aside on former researches.
Brake Squeal Noise를 유발하는 Brake Contact Interface와 Rotor의 In-Plane Modes에 관한 연구Ⅱ
김경수(Kyungsoo Kim),조호준(Hojoon Cho),김두영(Dooyoung Kim),최원석(Wonseok Choe),박영준(Youngjoon Park),백봉범(Bongbum Back),김한규(Hankyu Kim),고승석(Seungseok Ko),정명구(Myoungkoo Chung) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
For many years, brake noise has been one of the top automotive brake warranty issues, and many studies have been conducted to reduce the squeal phenomenon by improving the rotor-pad contact interface or by decoupling modes inducing squeals. This is additional research of ‘A study of Brake Contact Interface and Rotor In-Plane Modes Induced Disc Brake Squeal noise’. This paper considers the different brake contact interfaces affecting high frequency brake squeal and introduce an effective way of reducing the problem by improving one of the brake secondary contacts. Furthermore, the reason of improving of brake secondary contact has a positive effect is investigated by modal analysis & squeal noise analysis.
조용구,이해진,오재응,차병규,H. J. SIM 한국자동차공학회 2008 International journal of automotive technology Vol.9 No.2
This paper deals with friction induced vibration of a disc brake system with a constant friction coefficient. A linear, lumped, and distributed parameter model to represent the floating caliper disc brake system is proposed. The complex eigenvalues are used to investigate the dynamic stability, and, in order to verify simulations which are based on the theoretical model, an experimental modal test and dynamometer test are performed. The comparison of experimental and theoretical results shows good agreement, and the analysis indicates that modal coupling due to friction forces is responsible for disc brake squeal. Also, squeal type instability is investigated, using a parametric analysis. This indicates which parameters have influence on the propensity of brake squealing. This is helpful for validating the analysis model and establishing confidence in the experimental results of the modified system. These results may also be useful during system development or diagnostic analysis. This paper deals with friction induced vibration of a disc brake system with a constant friction coefficient. A linear, lumped, and distributed parameter model to represent the floating caliper disc brake system is proposed. The complex eigenvalues are used to investigate the dynamic stability, and, in order to verify simulations which are based on the theoretical model, an experimental modal test and dynamometer test are performed. The comparison of experimental and theoretical results shows good agreement, and the analysis indicates that modal coupling due to friction forces is responsible for disc brake squeal. Also, squeal type instability is investigated, using a parametric analysis. This indicates which parameters have influence on the propensity of brake squealing. This is helpful for validating the analysis model and establishing confidence in the experimental results of the modified system. These results may also be useful during system development or diagnostic analysis.