This is a comprehensive index to measure the quality of automobile manufacturing, which brings the most subjective and superficial feelings to automobile users. Automobile Nvh is one of the concerns of major automobile manufacturers and parts companies in the international automobile industry. Statistics show that about 1/3 of vehicle failures are related to nvh problems of vehicles, and nearly 20% of R&; Amp's expenses are spent on solving the nvh problem of vehicles.
As far as automobiles are concerned, nvh problems are everywhere. According to the source of the problem, it can be divided into three parts: engine nvh, body nvh and chassis nvh, and further subdivided into pneumatic nvh, air conditioning system nvh, road driving nvh and braking system nvh. Acoustic roughness, also known as roughness or impact characteristics, is related to the transient characteristics of vibration and noise, which describes the subjective feelings of human body to vibration and noise and cannot be directly measured by objective measurement methods.
The generation of automobile vibration and noise is not independent of each other, but closely related.
In order to improve the nvh characteristics of automobiles, we must first control the vibration and noise sources. Therefore, it is necessary to improve the structure of parts that produce vibration and noise, improve their vibration characteristics and avoid * * * vibration. Improve the balance of rotating elements; Improve the machining accuracy and assembly quality of parts, and reduce the impact and friction between relatively moving parts; Increase the flow rate of gas or liquid to avoid eddy current; Improve the structure and rigidity of the car body; Apply sound with the same amplitude but opposite phase as the noise source, and so on.