Experimental Study On Change Law Of Automobile Tire Pressure Under Dynamic Vertical Load

With the increase of vehicle population and constantly improvement of the vehicle speed,more and more attention is paid to the traffic safety.So the research of vehicle handling and stability is a hot topic in the research of automobile.Tires are the only components that connect the car to the pavement.In addition to air force and gravity,almost all other forces and moments which affecting vehicle motion are generated by the interaction between the rolling tire and the ground in the process of running.And the modern car almost all use pneumatic tire,tire pressure as a dynamic parameters in the automobile driving process,driving state of a vehicle and fluctuation characteristics of the road to a certain extend are characterized by tire pressure transient changes.Therefore,it is very important to study the law of tire pressure change of in the process of automobile driving.Based on the detailed analysis of the current situation of domestic and foreign research and the existing equipment conditions,this paper puts forward a method to study the change law of the tire pressure under dynamic load by the method of building the indoor tire.The main research work is as follows:(1)First of all,the tire dynamic load condition and the force mechanism of tire are analyzed in the interaction process of tire and pavement,and the reason of the change of tire pressure is analyzed theoretically.(2)The design of a MSP430F149 as the core,button battery powered tire pressure acquisition system,the design process of the hardware and software and the power consumption of the system are introduced in detail,and the function of collecting and storage the tire pressure signal is realized.(3)According to the shape structure of the pressure sensor and the tire valve nozzle,a sealing device which is composed of a pressure ring,a joint and a “o” sealing ring is designed to ensure the sealing performance of the tire pressure signal acquisition process.At the same time,according to the research purpose and the actual force mode of the automobile tire,the test bench is designed and built.Finally,the selection range of the test parameters is determined,and the corresponding test conditions are established.(4)Finishing test data,then the relationship of the tire dynamic load sized,dynamic load frequency,tire initial internal pressure and tire pressure change are analyzed by combination of time domain analysis and frequency domain analysis.