A mechanical model that can calculate the radial force variation of tire and wheel assembly to reduce the car shake

Abstract

Car shake is a vehicle vibration that occurs when a passenger car runs on a smooth road, and it causes dissatisfaction of a customer who purchased the passenger car. RFV that stands for radial force variation is defined in ISO 13326 and JIS D4233. RRO that stands for radial run out is variation of the rim diameter. RFV and RRO become the cause of car shake. Tire wheel RFV is measured by using a mass production road wheel, tire RFV is measured by using an accurate measuring road wheel. Car manufactures decide control values such as tire wheel RFV, tire RFV and wheel RRO to reduce car shake. And the control values are presented to production sectors, tire manufactures and road wheel manufactures. The relationship among tire wheel RFV, tire RFV and wheel RRO is evaluated experimentally to decide the control values. A mechanical model of tire wheel RFV that can calculate from tire RFV and wheel RRO is needed to decide appropriate control values. There are some technical papers of tire RFV that is managed by tire manufactures, but there are few technical papers of tire wheel RFV that is managed by car manufactures. In this study, a mechanical model that can calculate tire wheel RFV were developed to reduce car shake. This model has the following features. The parameters are the tire RFV and the value multiplied by wheel RRO and tire stiffness. This model is based on the complex plane and the Monte Carlo calculations. By using the complex plane, the model can calculate the relationship between tire wheel RFV and the assembly condition. By using the Monte Carlo method, the model can calculate average and standard deviation of tire wheel RFV.