Search Results

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.

A method of vehicle straight angle motion relative its axial axis by turning the front wheels and simultaneous braking of the external side wheels is offered. The equation describing the condition of four-wheel drive vehicle crab motion is obtained. The purpose of the research is to determine the law of control of torque on the wheels of the car, the realization of which makes crab motion possible. For realization of the aim, the following challenges were solved: the torque difference on the driving wheels (the braking torque on the outside wheel) that provides “crab motion" is determined; an analysis of the operational factors influences and design parameters of the vehicle, on the magnitude of the required torque difference, was conducted.

The dynamic distribution of normal reactions between the axles of the wheeled tractor has a significant impact on the stability against skidding and the wheeled tractor braking effectiveness. At the same time, the clarification of the normal reactions distribution between the axles allows to choose more rational braking forces distribution between the axles. It is shown that the best way to ensure the highest braking efficiency is the braking mode when the rear wheels of the tractor are at the blocking limit. An assessment of the expediency of installing brake mechanisms on only one axle of the tractor was made. The increase of braking efficiency of wheeled tractors with all brake wheels provided that they ensure directional stability is considered. The laws of braking forces distribution between the axles of wheel tractors for different sequence of wheels locking are determined.