1 Factors affecting bearing sealing performance
1.1 Influence of sealing material on bearing sealing performance
It is understood that the current sealing materials for small and medium-sized deep groove ball bearings are nitrile rubber, fluororubber, hydrogenated nitrile rubber and acrylate rubber.
material. For small and medium-sized deep groove ball seal bearings used in general washing machines, submersible pumps, motorcycles, and sewing machines, the rotation speed of the bearings is small.
At 3000r/min, and the temperature is lower than 130 °C, so the general price
A slightly lower nitrile rubber will suffice. By looking up the design manual, the temperature range of the above various materials is used.
The circumference is arranged as: fluororubber > acrylate > hydrogenated nitrile rubber > nitrile rubber. Therefore, the place where the temperature is required is high, and the sealing material is resistant to oil and temperature.
High performance requirements such as aging resistance, wear resistance and elasticity. The general nitrile rubber is not resistant to high temperature and is not suitable; although the fluororubber has good performance, it is expensive.
It should not be used. Hydrogenated nitrile rubber and acrylate rubber have good comprehensive performance, moderate price and high cost performance. Acrylate rubber is more resistant than hydrogenated nitrile rubber
High temperature, the bearing sealing material is used more.
1.2 The effect of sealing structure on sealing performance
The sealed structure of the sealed deep groove ball bearing is usually a straight inner ring, a grooved inner ring, and a grooveless inner ring. Inner ring straight structure
Sealed deep groove ball bearing processing technology is relatively simple, small and small bearings are used more, but the inner ring straight structure of the sealed deep groove ball bearing sealing performance
The machining precision of the bearing parts and the quality of the sealing ring are sensitive, so the dustproof and grease leakage effects are not good. Compared with the inner ring grooved and inner ring grooveless sealed deep groove ball bearings, the inner ring has a groove sealing performance with obvious advantages. The inner ring has a groove that is longer than the inner ring without grooved seal, which effectively prevents the grease inside the bearing from seeping.
Leakage, the entry of external dust, effectively improve the sealing performance. However, the grooved sealing structure of the inner ring is difficult in the manufacturing process, because the inner ring sealing groove is processed, the processing precision is also high, and the manufacturing cost is also improved. The inner ring grooveless sealed deep groove ball bearing processing technology is simple
More, the production process is also reduced, and it can also have good sealing performance under the condition of ensuring the processing precision.
1.3 The effect of sealing structure and lubricant matching on bearing sealing performance The role of lubricating grease in small and medium-sized sealed deep groove ball bearings is
To ensure that the bearing has sufficient lubrication, the bearing has a long service life. Select the grease to understand the use of the bearing, the use and
Use conditions to choose. Generally, it has the following characteristics: excellent stability and fluidity, excellent purity, excellent rust prevention, high and low temperature resistance,
Pressure resistance, good compatibility with rubber for seals, etc. The grease for low noise sealed bearings currently in use can be classified into the following
Three categories: general low noise motor bearing grease, high temperature long life low noise bearing grease, low temperature high speed bearing grease.
According to the relevant data, the optimal grease injection range of sealed bearings is 20% to 40% from the comprehensive performance. In bearing applications, special
In the case of high-speed operation, most of the grease is squeezed on the seal ring, the outer ring rib and the cage. The bearing movement space is almost free of grease and grease.
In the static space. Bearing lubrication does not rely on grease to enter the raceway, but relies on the base oil that is deposited from the grease. If the amount of fat is too small,
It is easy to cause poor lubrication during use, leading to early failure. In order to make the grease distribution in the bearing cavity uniform, after the bearing assembly is completed, it must be turned
The grease is homogenized at a speed of 1 to 3 minutes, so that too much grease is removed from the bearing, and the retained grease is evenly distributed. The leakage of the bearing is generally
In the early stage of use, after a certain period of time, the fat leakage rate slows down. After reaching the equilibrium state, the amount of grease leakage is extremely small, and even basically does not leak. So, if you want to drop
The low grease leakage rate must be greased before use. Two major factors affecting the sealing performance of sealed bearings are manifested in dense
The material and processing precision of the rubber seal ring of the bearing, the choice of the material of the seal must be based on the actual use of the bearing. Seal ring required skeleton
It has good rigidity, uniform material, anti-rust treatment on the surface and dimensional accuracy. The rubber material should be uniform, the physical properties meet the requirements, and
It has a certain elasticity and hardness, and needs to be matched with grease and anti-rust oil. It must be firmly bonded to the skeleton, and the structural shape and dimensional accuracy of the sealing ring should be consistent.
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