Research on lubrication and friction characteristics of oil seal with isosceles triangle texture and micro concave lip

Purpose This paper aims to study the effect of isosceles triangle micro concave texture with different parameters on the performance of oil seal to obtain a reasonable combination of parameters. Design/methodology/approach Based on the theory of elastohydrodynamic lubrication, a numerical model is established by coupling the texture parameters of isosceles triangle with concave lip with the two-dimensional average Reynolds equation considering surface roughness. Findings The results show that there is an optimal combination of parameters to improve the performance of the oil seal. When hp = 5µm-6.5 µm, a = 110°−130°, O = 1.4, C = 1.6 mm-2.2 mm, the oil seal with isosceles triangle micro concave texture can show good lubrication characteristics, friction characteristics and sealing ability. Originality/value The model provides a new idea for the design of new oil seal products and provides a theoretical support for the application of surface texture technology in the sealing field in the future.

Study on the Road Friction Database for Automated Driving: Fundamental Consideration of the Measuring Device for the Road Friction Database

This study deals with the possibility of construction of a database on the braking friction coefficient for actual roads from the viewpoint of traffic safety, especially for automated driving, such as level 4 or higher. At these levels of automated driving, the controller needs to control the vehicle. However, the road surface condition, especially the road friction coefficient on wet roads and snowy or icy roads, changes greatly, and in some cases, changes by almost one order. Therefore, it is necessary for the controller to constantly collect environment information, such as the road friction coefficients, and prepare for emergencies, such as obstacle avoidance. However, at present, the measurement of the road friction coefficients is not systemically performed, and a method for accurately measuring has not been established. In order to improve this situation, this study examines a method for continuous measurement of the road friction characteristics, such as the μ-s characteristics. It is shown that the μ-s characteristics are continuously measured using the MF generally used in tire engineering, and the friction characteristics identified from the results are sufficiently satisfactory.

TECHNOLOGY OF DEPOSITION OF COATINGS FROM HARD ALLOYS ON THE WORKING SURFACES OF FRICTION UNITS

A technology has been developed for applying explosively to the surface of centrifugal pump parts for pumping overheated distillate under NPP conditions of hard alloy coatings of the CrC-Ti system, which ensures high hardness of the coatings and the strength of their connection with the surface to be coated, and the best tribotechnical materials in comparison with existing materials friction characteristics against siliconized graphite in water.

Study on sliding friction characteristics of magnetorheological elastomer - copper pair affected by magnetic-controlled surface roughness and elastic modulus

To optimize the online friction coefficient adjustment, it is necessary to study the parameter change features of the magneto-sensitive polymer and its influence on the friction characteristics under magnetic field. A series of magnetorheological elastomers (MREs) with different initial surface roughness were prepared, and a sliding friction platform with MRE - copper block pair was built to carry out magnetic-controlled friction characteristic experiment. Results show that the sliding friction coefficient of MRE decreases with the increase of the magnetic field, but the degree of reduction is quite different under different initial surface roughness and elastic modulus. When the initial surface roughness of MRE is between 0.5 - 2.5 μm and the carbonyl iron particles (CIPs) volume fraction is between 10% - 15%, its magnetic-controlled friction coefficient has the largest reduced value of 22.75%. Moreover, features of elastic modulus and surface topography under magnetic field were tested and analyzed. By combining with the single peak contact model and the friction binomial law, the relationship between the surface roughness and elastic modulus of MREs and the sliding friction force is deduced, and it is proved that the friction coefficient is affected by the coupling effect of surface roughness and elastic modulus. The magnetic-controlled elastic modulus is the key factor, which determines the overall downward trend of the friction coefficient of MREs. Magnetic-controlled surface roughness also plays an important role in the adjustable range of friction coefficient, and reducing the initial surface roughness can increase the magnetic-controlled friction coefficient adjustable range.