Outside Tire Measurement System Research And Design

The economy of our country has witnessed rapid growth since the policy of the reform and opening-up. Accordingly, the number of people who tend to buy cars increases gradually. However, the problem of noise brought about by this has become increasingly serious. It not only influences people's physical and psychological health in a bad way, but also disturbs people's normal life.When the vehicle speed exceeds70km/h, the major source of the automobile noise is tyre noise. Combined with the current study situation of the mechanism of tyre noise at home and abroad and the study of generation mechanism of tire noise and the sound pressure and sound pressure level, sound intensity and sound intensity level, spectrum, octave analysis, loudness and loudness level, weighted sound levels of the air pump, the tread block impact, stick-slip, sticky suction, the tire lateral vibration, aerodynamic noise, horn effect, the cavity of the column and the Helmholtz resonance, this article explores three types of tyre noise testing methods frequently used nationally and internationally, which are respectively:Coast-By, Laboratory Drum, Trailer, and the related international standard; and then compares their advantages and disadvantages.According to project requirements, in accordance with ISO11819-2standard test specifications, a set of noise measuring system based on CPX is designed and developed. The system is composed of three parts:noise measuring system, environmental parameters testing system and PC noise measurement analysis software. Among them, noise measuring is the part of acoustic testing. The part of hardware is made up of14423measuring microphone that is manufactured by Hang Zhou Aihua Instrument Co, LTD, AWA14604ICP preamplifier and AWA6290M double channel noise analyzer. Signal transformation, filtering weighting network, octave and1/3octave in noise analysis are realized through signal processing technology, which are used for measuring and analyzing the tyre noise. Environmental parameter detection system is used to measure vehicle speed, temperature. Single-chip system that is made up of air velocity transducer is used to measure the environment parameter such as vehicle speed, temperature and wind speed for the correction of the amount of noise. The communication between subsystem and PC space is realized through USB. The Software uses Visual C#language, which can realize the time-domain analysis of the tire/road noise, A, B and C-weighted sound level, octave,1/3octave spectrum analysis. Besides, it can also simultaneously display and record the noise and various parameter detection analysis.At last, this set of system is used to achieve on-site measurement and analysis of tyre noise. The result of measurement reveals that this set of system is more convenient to use. It possesses good reproducibility of data. At the same time, this system is economical and convenient, which decides that it can be used for the analysis and study of tire noise for manufacturers.