New Roller Testing Unit for Vehicles

Abstract

The paper is devoted to investigating a roller testing unit with a closed circuit for testing wheeled vehicles. A distinctive feature of the unit is its rigid connection between cylindrical surfaces which causes a kinematic mismatch between their angular velocities of rotation. The authors consider the power and kinematic interaction of a vehicle wheel with cylindrical surfaces in a new type of testing units, and find experimentally an interaction between the power and kinematic parameters of the contact between a tire and a cylindrical surface in the driving mode. A mathematical model of the testing unit with a closed circuit is developed to analyze the behavior of power flows at various mismatching transmission ratios. Therefore, some recommendations for choosing reasonable values of transmission ratios for various types of testing for wheeled vehicles are given. The proposed testing unit provides a constant value of skidding, which expands the diagnostic capabilities of testers of this type. It makes possible to determine the elastic and traction qualities of tires in all running modes (driven, driving, or braking), to carry out running, short time and braking testing for vehicles, to test tires for wear, heat resistance and strength, to carry out shafting tests of engines with and without loading, to test the turning mode with accelerated testing of differentials, and to simulate different ground conditions under wheels by providing different kinds of skidding.

Friction Forces at the Wheel's Contact with the Ground in a Turning Vehicle

“…The best formula has the smallest number of empirical coefficients. Formula (5) had an advantage, because it contains only two empirical coefficients 1 and 2 [20][21].…”