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In the design of gearboxes and transfer boxes of heavy-duty vehicle`s transmissions, sliding bearings are often used as supports for gear wheels. Analysis of the results of statistical processing of gearbox parts failures and transfer boxes of wheeled tractors with a pulling force of 30 kN indicates the need to improve the reliability of the sliding bearings of the gear wheels. Such plain bearings ensure free rotation of the gear wheels in case of the torque transmission absence, and when locked by a clutch, the radial load of the gear wheel is sensed, while operating in the slipping rolling mode. Such units are poorly understood and in the technical literature sources there are no recommendations for their engineering, which often leads to errors when selecting operation gaps and press fitted in gear wheels. The manufacturers of the transmissions assemblies replaced the plain bearings, which in this case are made of metal-ceramic bushes, for roller bearings.

Plane bearings are used as rotating bearings for gear wheels of vehicles transmissions. The design of these units provides for the operation of bearings in two main loading modes: sliding mode (without load transfer) and rolling mode with slipping motion (with load transfer). The mode of sliding bearings operation in the rolling and slipping mode is not sufficiently studied, which makes it impossible to quantify at the design stage the influence of the operating conditions of the vehicle on wear processes, and, therefore, on their reliability. It is necessary to take into account the fact that the condition of the bearing coupling affects the conditions of the gearing. The results of statistical studies of wear and accelerated wearing tests of sliding bearings of gears of a wheeled tractor show the low reliability values of both gear wheels and sliding bearings.

This paper is devoted to the methods of increasing wear resistance, corrosion resistance, and service life of parts and assemblies of vehicles during their strengthening and renovation by the use of combined electric arc spraying (EAS) coatings. High density, adhesion, and microhardness of EAS coatings are provided by activation of the spraying process and subsequent nitriding of the sprayed coatings. This study is about the influence of technological parameters of the spraying process—composition, diameter and feed rate of sprayed wires, arc power, spray gas flow rate, spraying distance, speed of spraying spot movement, dispersion of spraying, etc.—on the qualitative characteristics of EAS coatings. The possibility of using pulsed ion nitriding (PIN) to improve the operational characteristics of EAS coatings made of wire materials is considered.

The bulk of automobiles are equipped with ABS currently. Having of automatic devices that prevent vehicle wheels from locking and skidding does not require consideration of the normal reactions on the front and rear vehicle axles wheels’ changes dynamics. However, ABS malfunction is possible for various reasons, and in this case the braking system must provide the safety vehicle braking. To provide this, it is necessary to return to the problem of choosing the rational braking forces distribution between the wheels of the front and rear axles.

New solutions for actual problems of determination the efficient distribution of braking forces between the axles of the vehicle, and the stability and drivability of two-axles vehicles at service braking are received in the thesis. It permitted for the first time to determine the Law of distribution of the braking forces between the axles, that ensuring straight-running stability of two-axle vehicle at service braking, to obtain the ideal characteristics for the braking system of two-axle vehicle at service braking and to determine possible values for the distribution of braking force on the front axle. The drivability criterion at service braking obtained further development; it is offered to use boundary at gripping front or rear wheels angular vehicle acceleration on the road.

Vehicle practices sometimes require rapid assessment of the road gradient. The most common means to this is a satellite navigator with a barometric altimeter (BA). However, this is not always possible due to local or weather conditions. For such cases, the method of points of equal velocity (PEV) was proposed to measure parameters of the car forward movement and then of reverse movement through the same point and at the same speed and calculate the necessary road/car parameters. Driving through the same point in opposite directions at the same speed eliminates the unknown grade and rolling resistance, after which the system of equations is solved with a minimum of assumptions. Detailed recommendations given on measurements with the global positioning system (GPS)/Global Navigation Satellite System (GLONASS) navigator with BA and processing of results based on the author’s practical experience and because of their absence in the manuals.