1.Universality of abnormal sound
Strolling along the street, as long as you pay attention, you can often hear a sharp "squeaking" strange cry from different models of cars at the beginning of the vehicle or at low speed (low speed shift). When maintaining various models of cars, we often hear different degrees of fan belt ringing when testing machines. Among them, there is a slight "squeaking" sound of fan belt, air compressor belt or generator belt at idle speed; There is a sharp "squeaking" sound during acceleration or high-speed working conditions; There is a sharp "squeaking" sound when the vehicle starts at the beginning or shifts gears at a low speed. This is very common in many cars such as Santana, Jetta, Fukang, Peugeot, Chang 'an, Otto, Xiali, and many mini-vans such as Changhe, Chang 'an, Songhua River, etc. Where ordinary V-belts are used as fan belts, fan belts have sounded, and other light and medium-sized buses and trucks occasionally have fan belts, but the relative incidence rate is low.
2. Traditional methods and effects of eliminating abnormal sound
Drivers hate the noise of the fan belt. Under normal circumstances, drivers and mechanics have the following methods to deal with the noise of the fan belt.
1) Replace the fan belt with a new one: the time to eliminate abnormal noise is half a day to 30 days, and the time is inversely proportional to the smoothness of each belt groove, that is, the smoother the belt groove of the pulley is ground, the shorter the noise removal time is, and the original abnormal noise will appear soon.
2) Replace the generator pulley with a new one: the time to eliminate abnormal sound is10-45 days, which is also inversely proportional to the smoothness of the pulley groove, even if a new fan belt is replaced at the same time.
3) Strongly increase the tension of the fan belt: the time to eliminate abnormal sound is from 1 hour to 10 day. The time to eliminate abnormal sound is inversely proportional to the smoothness in the pulley groove and the smoothness of the working surfaces on both sides of the belt.
4) Apply a small amount of engine oil to the working surfaces on both sides of the fan belt. The time to eliminate abnormal sound is 5-15 days. A little more oil will take a little longer to eliminate abnormal noise.
From the above methods, it can be seen that although abnormal noise can generally be stopped at the time of treatment, on the whole, the holding time is very short, especially after all pulley grooves are polished smoothly, it is possible to recover the noise in the afternoon after treatment in the morning. In addition, the first and second methods increase expenses and labor hours; The third method will affect the service life of belt, and also affect the service life of water pump and generator bearing; The fourth method also affects the service life of the belt. Therefore, after several times of poor treatment results, some drivers think that it takes a lot of effort and money to solve the problem fundamentally. Anyway, there is only noise and no other harm, so let it go!
3. Adopt "microwave grooved pulley" to radically cure the fan belt noise.
According to the analysis of the methods and effects used to eliminate the noise of the fan belt, it can be affirmed that the abnormal noise is caused by the mutual slippage between the fan belt and the belt groove. The key point is that the rubber surface of the working face on both sides of the fan belt loses its good friction coefficient and cannot maintain the good elasticity of rubber for a long time. The reason for this result is that the rubber surface of the working face becomes smoother and harder after being squeezed in various conventional belt grooves with V-shaped oblique straight geometry for a long time.
At this point, another problem has arisen, that is, the triangle fan belt is also widely used in engines with large displacement, except that the model of the triangle belt is "A" or "B" of a larger level, and the diameter of the belt groove of the pulley used is larger. Why does the fan belt ring rarely occur? A comparative analysis shows that:
"A" or "B" V-belt has a wider working surface ("B" is wider than "A" and "A" is wider than "O"), and each pulley has a larger diameter, so the contact area between them is larger and the torque capacity can be transmitted. When the engine displacement is large, the maximum speed is generally low, and the cross-sectional area of the fan belt (V-belt) is large, so the possibility of vibration and slippage of the fan belt is small; It is precisely because the maximum speed of the engine with "B" V-belt is relatively low, which makes the speed rise time ratio of accessories such as water pump, generator and air compressor from idle speed to high speed small and the time change process is slow, so the possibility of fan belt slipping is less. Because of these differences and influences, the phenomenon of fan belt ringing rarely occurs when the "B" type fan belt is used in engines with large displacement. Moreover, the low-displacement engine is not suitable to use the "B" V-belt as the fan belt because of its small size, so as to overcome the problem of fan belt ringing.
The microwave grooved pulley is simple in structure and easy to manufacture; When in use, the structure of the original car is not changed, and the service life of the V-belt is not affected; The effect is immediate, and the problem of fan belt ringing can be effectively eradicated for a long time.