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Analysis of Friction Coefficient Variation with Moisture between Friction Surfaces
Technical Paper
2016-01-0411
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
If a vehicle is left in a humid environment, the coefficient of friction between the brake pads and discs increases, generating a discomforting noise during braking called brake squeal. It is assumed that this increase in the coefficient of friction in a humid environment is the effect of moisture penetrating between the brake friction surfaces. Therefore, this paper analyzes the factors causing coefficient of friction variation with moisture between the friction surfaces by dynamic observation of these surfaces. The observation was achieved by changing the disc materials from cast iron to borosilicate glass. One side of the glass brake disc was pushed onto the brake pad and the sliding surface was observed from the opposite side by a charge coupled device (CCD) camera. First, a preliminary test was carried out in a dry state using two pad materials with different wear properties to select the appropriate pad for observing the friction surfaces. Then, the characteristics of coefficient of friction variation when the disc material was changed from cast iron to glass were identified using two pad materials with a wear properties close to that of the selected pad. This confirmed that the coefficient of friction variation was qualitatively the same for the cast iron and glass pads. Finally, the results of the observation of moisture on the friction surfaces found that a mixture of wear debris and water had a large effect on coefficient of friction variation.
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Authors
- Yosuke Akita - Toyota Motor Corporation
- Kenji Abe - Toyota Motor Corporation
- Yoshihiro Osawa - Toyota Motor Corporation
- Satoshi Wakamatsu - ADVICS Co., Ltd.
- Kyoko Kosaka - ADVICS Co., Ltd.
- Yoshitsugu Goto - Toyota Central R&D Labs., Inc.
- Yuji Nagasawa - Toyota Central R&D Labs., Inc.
- Noboru Sugiura - Toyota Central R&D Labs., Inc.
Citation
Akita, Y., Abe, K., Osawa, Y., Goto, Y. et al., "Analysis of Friction Coefficient Variation with Moisture between Friction Surfaces," SAE Technical Paper 2016-01-0411, 2016, https://doi.org/10.4271/2016-01-0411.Also In
References
- Inoue , M. Studies on Friction Materials of Automobile: 1st Report, Squeal of Disc Brake Pad Transactions of the Japan Society of Mechanical Engineers C 51 466 1433 1439 1985
- Eriksson , M. , Lord , J. , and Jacobson , S. Wear and contact conditions of brake pads: dynamical in-situ studies of pad on glass Wear 249 272 278 2001
- Takase , N. , Eguchi , M. , and Yamamoto , T. Visualization of True Contact Surface Area of Automotive Brake Friction Materials Proceedings of JAST Tribology Conference 447 448 2008
- Ostermeyer , G. On Tangential Friction Induced Vibrations in Brake Systems SAE Int. J. Passeng. Cars - Mech. Syst. 1 1 1251 1257 2009 10.4271/2008-01-2580
- Kobayashi , M. and Hyodo , M. Stabilizing Friction Coefficient of Disc Brake Pad in Cold Condition Proceedings of the Society of Automotive Engineers of Japan 972 17 20 1997
- Kotani , N. , Kobayashi , M. , and Kakihara , K. Friction Coefficient Phenomenon of Disc Brake Pad in Humidity Environment Proceedings of the Society of Automotive Engineers of Japan 97-98 5 8 1998
- Ono , M. , Nagayoshi , T. , Unno , M. , and Kaburagi , T. Automotive Brake Disc Pad with Stable Friction Coefficient Hitachi Chemical Technical Report 46 55 59 2006
- Eriksson , M. , Lundqvist , A. , and Jacobson , S. A study of the influence of humidity on the friction and squeal generation of automotive brake pads Proc. of IMechE 215(D) 329 342 2001 http://dx.doi.org/10.1243/0954407011525674
- EL-Tayeb , N.S.M and Liew , K.W. On the dry and wet sliding performance of potentially new frictional brake pad materials for automotive industry Wear 266 275 287 2009 http://dx.doi.org/10.1016/j.wear.2008.07.003