The Role of Friction Film in Friction, Wear, and Noise of Automotive Brakes

Rhee, Seong Kwan; Jacko, M. G.; Tsang, P.H.S.

doi:10.4271/900004

Cited by 45 publications

(29 citation statements)

References 5 publications

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“…In several studies of brake system [66,40,60] wear rate was found to increase with increasing temperature. For a friction material with phenolic resin as binder, the wear rate below a critical temperature shows a slow increase, but above it the wear rate increases rapidly as shown schematically in figure 24.…”

Section: Wearmentioning

confidence: 99%

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Overview of disc brakes and related phenomena - a review

Rashid

2014

IJVNV

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Disc brakes have evolved over time to be a reliable method of decelerating and stopping a vehicle. There have been different designs of disc brake systems for different applications. This review gives a detailed description of different geometries of the components and the materials used in a disc brake system. In spite of all the improvements, there are still many operational issues related to disc brakes that need to be understood in a greater detail and resolved. There has been a lot of research going on about these issues and at the same time different methods are being proposed to eliminate or reduce them. There has also been an intensive fundamental research going on about the evolution of tribological interface of disc-pad system. One major purpose of the present paper is to give a comprehensive overview of all such developments.

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Section: Wearmentioning

confidence: 99%

“…The films should not be considered as continuous but more like regions attached to the surfaces [43,58,60]. Third body layers prevent direct contact between the friction partners and reduces wear [66,42]. A transfer film can fill grooves and wear troughs and make disc surface smoother [57].…”

Section: Friction Film Disc Padmentioning

confidence: 99%

Overview of disc brakes and related phenomena - a review

Rashid

2014

IJVNV

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“…The concept of an Interface Layer or Tribolayer has been used to distinguish the difference between the surface layer and the main bodies of the pad and disc. The Interface Layer formation has became a common and wide accepted phenomenon in vehicle braking [2,[22][23][24] and has been considered in as an important element in modeling of the braking process. For example, Day [2] examined the role of interface contact resistance in the calculation of heat flow and temperature generated in brake friction pairs using FEA using a 'five-phase model', i.e.…”

mentioning

confidence: 99%

Investigation of disc/pad interface temperatures in friction braking

Qi¹,

Day²

2007

Wear

108

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Maintaining appropriate levels of disc-pad interface temperature is critical for the overall operating effectiveness of disc brakes and implicitly the safety of the vehicle.Measurement and prediction of the distribution and magnitude of brake friction interface temperatures are difficult. A thermocouple method with an exposed hot junction configuration is used for interface temperature measurement in this study.Factors influencing the magnitude and distribution of interface temperature are discussed. It is found that there is a strong correlation between the contact area ratio and the interface maximum temperature. Using a designed experiment approach, the factors affecting the interface temperature, including the number of braking applications, sliding speed, braking load and type of friction material were studied. It was found that the number of braking applications affects the interface temperature the most. The real contact area between the disc and pad, i.e. pad regions where the bulk of the kinetic energy is dissipated via friction, has significant effect on the braking interface temperature. For understanding the effect of real contact area on local interface temperatures and friction coefficient, Finite Element Analysis (FEA) is conducted. It is found that the maximum temperature at the friction interface does not increase linearly with decreasing contact area ratio. This finding is potentially significant in optimising the design and formulation of friction materials for stable friction and wear performance. Tave Change of average temperature of the brake pad body (°C) DoE A statistical design of experiments approach emf ElectroMotive Force WIRE An exposed wire thermocouple configuration for brake disc/pad interface temperature measurement RUB A rubbing thermocouple for brake disc surface temperature measurement Key words

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“…Whether squeal is generated depends on the pressure value for brakes on the frictional contact surface between the disks and pads. In addition, when pads are worn out by braking, squeal is generated even if it was not generated when the pad was new (1) .…”

Section: Introductionmentioning

confidence: 99%

Influence of Brake Pad Thickness on Disk Brake Squeal

Oura¹,

Kurita²,

Nishizawa³

et al. 2010

JSDD

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A squeal test using a pad with a different thickness demonstrated that a squeal with a higher frequency can be generated if a thin pad is used. The factors that changed as a result of pad thickness were termed 'difference of pad rigidity' and 'dimension difference in the thickness direction of the pad,' and the influence each factor exerted on the squeal was clarified. First, the dynamic stiffness of the pads used for the squeal tests were measured by adding a vibration that imitated the frequency and amplitude of the squeal. The measurement showed that the pad rigidity becomes hard when the pad thickness becomes thin. In addition, the pad vibrated with the same amplitude and the same phase from the frictional contact surface to the back plate in the thickness direction. The pad rigidity is in inverse proportion to the pad thickness because the pad can be viewed as springs in series in the thickness direction. Next, the influence that pad thickness exerted on squeal was analyzed by using a surface-contact-analysis model that reproduced the pad rigidity with a distributed spring and the dimension difference in the thickness direction of the pad with distance from the contact surface to the rotational center of the pad. Results showed that the squeal frequency becomes high when the pad rigidity becomes hard. If the dimension in the thickness direction of the pad becomes small, the squeal is not generated easily; however, the dimension does not influence the squeal frequency.

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The Role of Friction Film in Friction, Wear, and Noise of Automotive Brakes

Cited by 45 publications

References 5 publications

Overview of disc brakes and related phenomena - a review

Overview of disc brakes and related phenomena - a review

Investigation of disc/pad interface temperatures in friction braking

Influence of Brake Pad Thickness on Disk Brake Squeal

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