nvh is

noise (noise)

vibration (vibration)

Harshness (Irregularity)

The first letter of the three words

It represents the vibration and noise comfort of the entire vehicle

In the previous issue, I introduced one of the important contents of "NVH": Wind noise，Another important content of "NVH" today: Road noise。

What is road noise?

Auto tires as important components in the driving system，Drives the whole vehicle、Moly impact force from the road、Driving and adhesion through contact with the road、Provides balanced centrifugal force and side resistance during turning and produces a positive torque。Auto road noise refers to the driving process of the car，Due to the continuous collision and friction of the tire and the pavement，Noise seabet loginthat can be heard inside the vehicle generated。When the car is driving，Road noise is inevitable，When the car is driving at low speed at medium speed，The main ingredient of road noise occupies the noise in the car。

How is road noise generated?

Specifically，The road noise is mainly formed by the following three parts: the vibration and impact sound of the first yi part is due to the uneven road，Pass to the car through the chassis and body，Mainly from the road、Chassis structure and body structure decision; Part 2，Vibration and noise caused by the resonance of tire cavity，Pass to the car through the chassis structure and body structure，It is mainly determined by the diameter and flat ratio of the tire; the third part is when the vehicle is driving on the road，The friction sound generated by the surface of the tire and the ground and air friction、Tire rolling disturbance of the aerodynamic noise generated by dynamic flow、The gap between the tire surface pattern and the ground continuously exposed to the pump gas noise caused by pump gas，Mainly pattern on the surface of the tire、Tank Deep、Pitch decision。

Learn the principle of noise production of car tires and roads，You can know the main factor of road noise，If: Tire、Path、Driving conditions、Car habits, etc.。

1、Tire rubber quality。The tires of the car are made of rubber material，Rubber quality，Vibration reduction effect is good，Can reduce the incentive of the road on the tire。Use the soft tires of rubber，It is conducive to reducing tire noise，But the abrasion resistance is worse。

2、Tire size。Use as small tires as possible，can reduce the contact area of ​​the tire and the pavement，can also reduce road noise，But the braking performance and control performance will be worse。

3、Different roads。At present, there are many types of domestic roads，The noise generated when driving on different roads is also different。For example，Driving on a relatively smooth asphalt pavement，Incentives to tires on the road，The road noise will be smaller; in the relatively rough asphalt roads、Even the damaged asphalt pavement drive，Incentives to tires on the road，Road noise will be larger。

4、Car habit with car。When opening the sunroof or window，Road noise will be transmitted directly to the car，Road noise is naturally obvious; northern users use snow tires in winter，The rubber used in snow tires is soft than summer tires and four seasons tires，Will reduce pavement incentives，But because of the tire pattern slot of the snow tires, deep，will produce "tire singing" sound，Bad tire "tire singing" sound is very obvious; reasonable reducing tire gas pressure can help reduce road noise。

5、Previous:。The non -normal wear caused by abnormal tires caused by abnormalities of the four -wheel positioning parameters will make the road noise worse; the tire motion balance is not good，Anomal vibration and noise related to the speed related to the speed of the vehicle。