Comparative method is the enterprise to promote technological progress, a shortcut to improve the quality of products, through the analysis and comparison of the domestic and foreign similar samples, get each other a lot of information technology, quality, draw lessons from foreign products in the structure of the advantages of the technology and characteristics of our advantage, overcome the enterprise in product quality and technical level of disparity and the insufficiency, improved, to catch up with advanced level at home and abroad, strengthen market competition ability, to win the domestic and foreign markets, to lay a solid foundation.
I. bearing vibration acceleration
Bearing vibration acceleration value is in S0910 (Ⅲ).The vibration accelerations of steel balls in different columns of hub bearings are mainly tested.From the vibration of on-frequency band, the average vibration value of domestic bearings is 5.8db higher than that of foreign bearings.From the different frequency band, the domestic bearing in the high frequency band is obviously higher than the foreign bearing.This is related to many factors such as the parallel difference of the two raceway, the ripple degree, the roughness, the quality of the steel ball, the cleanliness of the bearing and so on.
Bearing clearance and rotation accuracy
The axial clearance of foreign bearings is much smaller than that of domestic bearings.The rotating precision of foreign bearings is obviously higher than that of domestic bearings.Bearing clearance and rotation accuracy have important effects on the sealing performance. The larger the clearance, the lower the accuracy and the worse the sealing effect.
Iii. Bearing grease filling capacity
The filling quality of domestic bearings is 27% more than that of foreign bearings.Since it is impossible to accurately calculate the net space inside the bearing, it is impossible to know the filling percentage.However, due to the large diameter of bearings in foreign countries, the number of steel balls is small, the seal skeleton steel plate is thin, so the net space of foreign bearings should be larger than that of domestic bearings.It can be concluded that the grease filling rate of domestic bearings is more than 27% higher than that of foreign bearings.
Three lip seal is used in the profile of bearing seal both at home and abroad, but the structure is different.The differences are:
1. The contact interference or clearance between the three sealing lips and the oil swing ring are different.
Foreign bearing 2 lip sealing interference is small, 3 lip is clearance seal, 1 lip interference and domestic bearing is equal.In general, foreign bearings for low torque seal, friction torque, interference, contact force are small, the bearing temperature rise should be lower than the domestic bearing temperature rise.
2. Structure difference of seal 3 lips.
Foreign and domestic bearing seals 3 lip direction is opposite, and foreign bearing seals 3 lip and oil swing ring for clearance.When the bearing rotates and the temperature increases, the gas pressure in the inner space of the bearing must increase.In figure 1, since the gap between the 3 lips and the oil ring is not obstructed, the leakage channel will be formed through the 2 and 1 lips when the pressure is relatively small.As the pressure difference between inside and outside is small, the grease leakage will be slow.In figure 2, when the pressure is small, the sealing interference of the three lips will increase with the increase of the pressure.When the pressure is high enough, the three lips will be pushed away in an instant, forming a pressure outlet channel through the two and one lips. The pressure and grease will be released locally in an instant.
3, seal 1 lip structure differences
The included Angle of 1 lip of foreign bearing seal and bearing axis line is relatively large. Although the contact interference is the same as that of domestic bearing, the contact area is relatively large and the contact force is small.On the one hand, the friction torque is reduced, on the other hand, the sealing effect is strengthened.
4, seal 2 lip structure differences
Abroad bearing seal 2 lip root is thinner, the end is thicker, and the end contour is inclined upward.A storage space is formed between the two and three lips.Domestic bearing 2 lip thickness is relatively uniform, 2 lip and 3 lip between the area is less than the storage of foreign mud, dust.
5. Ability to resist foreign mud and dust
Foreign mud, dust will enter through clearance 4, the first to stay in the space, space full, through the space, into the bearing interior.Foreign bearing space,, have the function of storage, domestic bearing only space, has the function of storage.Therefore, foreign bearing has a better ability to resist foreign mud, dust.
Five, the conclusion
1, the foreign bearing axial clearance is relatively small, high rotation accuracy, to improve the sealing effect is very beneficial.
2. The filling amount and filling rate of foreign bearings are at least 27% lower than that of domestic bearings, and the filling amount of domestic bearings is too much.
3. Both foreign and domestic bearings adopt the type of three-lip seal and oil swing ring, but there are obvious differences in the structure of the three lips.Foreign bearing seal is a low torque seal, friction torque is small, less heat, has an excellent ability to resist foreign mud, dust, also has a better ability to prevent grease leakage.Domestic bearing sealing structure in the ability to resist foreign mud, dust, in the prevention of grease leakage is better, but because of the friction torque, high temperature rise, make the grease become thin, the bearing inside and outside pressure difference increases, plus the grease loading too much, thereby reducing the effect of preventing grease leakage.