Electrothermomechanical Friction of Wet Elements of Automotive Disc-shoe Brakes

Authors D.A. Volchenko1 , M.V. Kindrachuk2 , N.A. Volchenko3, S.V. Nikipchuk4, M.M. Nasirova5, N.B. Klochko1, A.O. Yurchuk2

1Ivano-Frankivsk National Technical University of Oil and Gas, 15, Karpat·sʹka Str., 76000 Ivano-Frankivsk, Ukraine

2National Aviation University, Liubomyra 1, Guzara Ave., 02000 Kyiv, Ukraine

3Kuban State Technological University, 2, Moskov St., 350042 Krasnodar, Russia

4National University "Lviv Polytechnic", 12, S. Bandera St., 79000 Lviv, Ukraine

5Azerbaijan Aviation Academy, 30, Mardakan Prosp., Baku, Azerbaijan

Issue Volume 12, Year 2020, Number 6
Dates Received 16 August 2020; revised manuscript received 17 December 2020; published online 25 December 2020
Citation D.A. Volchenko, M.V. Kindrachuk, N.A. Volchenko, et al., J. Nano- Electron. Phys. 12 No 6, 06020 (2020)
DOI https://doi.org/10.21272/jnep.12(6).06020
PACS Number(s) 81.15. – z, 61.43.Gt, 52.40.Hf
Keywords Disc-shoe brake, Friction couple, Microasperity, Water (10) , Steam, Longitudinal and transverse double electric layer.

In the article, attention is paid to the factors affecting the limiting wetting angle of both polished and matte side surfaces of solid and self-ventilated discs of vehicles brake devices when they are moving on a wet roadbed. The following factors are considered: the material of the friction elements and its structure, the energy level of the surface layer, the topography of the friction surfaces and the geometric parameters of their microasperities, the presence of pores and grooves in them, capillary, centrifugal and inertial forces and moments, dynamic equilibrium between the energy level of the friction surface and a water film on it. In examining the microgeometry of the disc friction surface, its area, the ratio of the microasperities height to their pitch, the intensity of changes in their height and the degree of contamination were taken into account. It was found that the surface microgeometry affects the heat of desorption of the water film. The research of the above factors has shown that the driving force of the processes and effects in wet brake friction couples are potential gradients arising as a result of action of transverse and longitudinal electric double layers. The triboelectric water-effected phenomena were studied. The test results of self-ventilated disc-shoe brakes of MAN trucks (model TGA 26.420) with dry and wet friction couples tested with 20fold cyclic braking are presented (speed drop 30 km/h per 1 min). The registered temperature at the interface was 320-340 °C. As a result of the road tests carried out on a truck with wet brake friction couples, regularities of the braking time, braking torque and braking distance depending on the dynamic coefficient of friction were established. The analysis of the obtained data was carried out. The results of studies of the negative effect of water penetration into disc-shoe interface are given.

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