Deep groove ball bearings have a variety of sealing structures. According to the different sealing materials, they are mainly divided into two types: rubber sealing ring and dust cover (standard iron cover): according to different seals, they can be divided into contact sealing and non-contacting. seal. For sealed deep groove ball bearings such as motorcycles, home appliances motors, luxury ceiling fans, etc., the basic sealing structures commonly used at present mainly have the following five forms.
The sealing structure belongs to the sealing structure of the sealing groove contact type. The inner ring of the bearing has a sealing groove, the sealing ring and the sealing groove form a labyrinth shape, the sealing route is long, and the buffer zone is provided, which is beneficial to sealing, especially suitable for sealing solid particles such as dust. However, due to the difficulty of processing and production costs, the sealing groove of the bearing ring is generally no longer processed after turning and heat treatment. Therefore, the processing accuracy of the sealing groove of the bearing ring is limited, resulting in the sealing ring lip and the sealing groove The matching accuracy of the seal ring is not high: Moreover, because the angle between the oblique line of the inner ring seal groove and the vertical line that is in contact with the seal ring lip is generally only a few degrees, the tightness of the seal ring lip and the seal groove is affected by the inner and outer sides. The axial size of the ring seal groove (the axial position of the seal groove) has a great influence. The axial size of the seal groove of the outer ring changes, and the axial positioning position of the bearing seal ring also changes; or the change of the axial size of the oblique line of the inner ring seal groove in contact with the lip of the seal ring will directly affect the seal ring and the inner ring seal groove. The matching accuracy. Therefore, the seal ring lip of this structure has a large fit interference with the inner ring seal groove. The seal ring lip either has too little contact deformation, which affects the sealing effect, or the contact deformation is too large, which increases the contact surface. The frictional torque and bearing rotating torque cause the vibration and noise of the bearing to increase and the temperature rise is too high and too fast when the bearing is working.
The seal structure belongs to the inner and outer diameter contact seal structure. The difference from the groove contact seal structure in Figure 1 is that the inner ring of the bearing does not have a seal groove, and the sealing route is short, which is not conducive to sealing. But the advantage is that the outer diameter of the inner ring can be grinded to greatly improve the dimensional processing accuracy and reduce the roughness, and this sealing structure is sealed through the contact between the lip of the sealing ring and the outer diameter of the inner ring, and is generally not sealed The influence of the axial positioning of the ring has nothing to do with the machining accuracy of the axial dimension of the seal groove of the outer ring of the bearing. Therefore, the matching accuracy between the lip of the sealing ring and the outer diameter of the inner ring is high, and the dispersion of the interference is small, which is beneficial to the improvement of the sealing performance. At the same time, due to the better roughness of the outer diameter grinding of the inner ring, the bearing has a smaller friction torque than the groove contact seal structure under the same sealing effect.
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The sealing structure is called double lip seal, which not only has the sealing advantages of the first structure, but also has the sealing advantages of the second structure, so the sealing effect is better. However, due to the limitations of current processing conditions and production costs, it is difficult for both lips to achieve an ideal contact and sealing state at the same time. Therefore, it is generally ensured that the radial direction has a better contact state, and the axial direction allows non-contact state. If you consider the sealing effect of the outer lip of the sealing ring, it can also be called a three-lip or multi-lip seal. Since this structure requires high processing precision of the sealing ring and the sealing groove of the ferrule, and the production cost is relatively high, it has not been widely adopted. With the continuous development of sealing ring and ferrule processing technology and the continuous improvement of processing quality, the multi-lip seal structure will be the development direction of bearing high sealing performance. For example, for the precision low-pitched automotive bearings produced by some domestic bearing manufacturers, the sealing groove is ground with a shaped grinding wheel, which greatly improves the processing accuracy of the sealing groove and the accuracy of matching with the sealing ring, so that the sealing performance of the bearing is improved. And the quality of vibration and noise has been significantly improved.
The sealing structure is a non-contact rubber sealing structure. Compared with the groove contact sealing structure in Figure 1, the sealing effect is worse, and it is especially not suitable for sealing against oil leakage and waterproofing. However, its advantage is that the processing accuracy requirements for the sealing ring and the sealing groove of the ferrule are not as high as those required by the structure in Figure 1, so it has a greater advantage in terms of production cost control.