FAG Deep Groove Ball Bearing Seal Structure

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FAG deep groove ball bearing seal structure analysis

FAG 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 the different sealing arrangements, they can be divided into contact sealing and non-contact Type 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.

(1) Groove contact type sealing structure

The inner ring of FAG bearing has a sealing groove. The sealing ring and the sealing groove form a labyrinth shape. The sealing route is long and has a buffer zone, which is conducive to sealing, especially suitable for sealing solid particles such as dust. However, due to the difficulty of processing and production cost, 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 contacts 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 seal ring lip will directly affect the seal ring and the inner ring seal groove The matching accuracy. Therefore, the sealing ring lip of this structure has a large interference fit with the inner ring seal groove, and the sealing ring lip either has too little contact deformation, which affects the sealing effect, or the contact deformation is too large, increasing 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.

(2) Inner and outer diameter contact sealing structure

The difference with the groove contact seal structure is that the inner ring of the bearing does not have a seal groove, and the sealing route is shorter, 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 by contacting the outer diameter of the inner ring with the lip of the sealing ring, and is not normally 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 FAG bearing. Therefore, the matching accuracy between the sealing ring lip and the outer diameter of the inner ring is high, and the interference dispersion 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.

(3) Double lip seal

It not only has the sealing advantages of the groove contact type sealing structure, but also has the sealing advantages of the inner and outer diameter contact type sealing 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 to ensure that the radial direction has a better contact state, and the axial direction allows non-contact state. If the sealing effect of the outer lip of the sealing ring is considered, 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 high production cost, 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.