Inclined Wheel Normal Stiffness Calculation Procedure

The standard concept of the normal wheel stiffness factor is defined for the vertical wheel installation so that its rotation plane is perpendicular to the reference plane. Until today, no one has presented the dependencies for the inclined wheel normal stiffness factor calculation. But we have discovered the change in the normal wheel stiffness with its inclination. At the same time, for the design simulation of the automobile active safety properties with an inclined wheels installation, the dependencies used to calculate the normal stiffness are the same as for a vertical tire. This is incorrect and reduces the simulation adequacy. The aim of this study is to develop a universal methodology for calculating the normal stiffness of an inclined wheel. A universal method for calculating the normal stiffness factor of an inclined resilient wheel has been developed. Experimental studies of the inclined wheel tire normal stiffness were carried out on a specially designed experimental unit at Volgograd State Technical University. A universal calculation and experimental dependence are obtained for the resilient wheel normal stiffness factor calculation, with rotation plane inclined at an angle from 0° to ± 6°. It was found that, regardless of the wheel inclination direction, the normal tire stiffness decreases, which increases its normal deformation at the same load. This reduces the slip angle but increases the steered wheels oscillations. Each of these processes can proceed slower or faster, depending on the wheel movement mode. A correction factor is obtained for converting the vertically positioned wheel normal stiffness into the inclined wheel normal stiffness. This function is valid for wheel inclination angles of 0° to ± 6°. It can be applied to both radial and diagonal tires of cars and trucks.