What is a sealed bearing?
The so -called seal bearing is the dust -proof bearing, so that the bearing is sealing to maintain the smooth conditions and the normal operating environment of the bearing, give full play to the function of the bearing, extend the service life of the bearing, and have suitable sealing of the rolling bearing to avoid leakage and leakage and leakage agents and the leakage and the smoothing agent. The invasion of dust, water or other dirt. This is conducive to the protection of bearings.
Bearing dense seal type:
According to a detailed understanding of the China Bearing Network, rolling bearing is a common type in daily life. The sealing device structure of the rolling bearings is mainly divided into contact sealing and non -contact sealing.
Non -contact sealing of the bearings
Bearing non -contact sealing is a sealing method of designing small gaps between the bearing and the bearing side cover. The sealing structure does not contact the axis, so there is no friction or wear, and it is suitable for high -speed rotation. In order to strengthen the sealing effect, you can fill the grease at the gap. The bearing non -contact seal is mainly: gap sealing, oil groove sealing, maze sealing, oil -shaking tight seal, etc.
1. Gap sealing
The gap seal is a small cycle gap left between the shaft and the bearing covering hole. The radius gap is 0.1-0.3mm. The longer the gaps, the smaller the sealing effect. In order to improve the sealing effect, multiple side -by -side grooves can be opened in the bearing cover and filled with grease in the groove. If it is used for lubricating oil sealing, the thread groove can be carried out on the hole wall of the bearing cover. The lubricant that wants to leak out is sent back to the bearing inner inner inner inner inner bearing due to the spiral transportation effect. Essence
2. Oil tank sealing
The oil groove seal is processed with a ring oil groove at the nephew of the inner cavity of the bearing seal, and its radial distribution is distributed with oil guide grooves. Each ring oil gauge is connected with the oil tank and the fuel tank. Decide. The device is simple. The sealing cover is not too long, the structural space is small, and the structure space can be better solved.
3. Labyrinth seal
The basic principle of this seal is to form a runway with great fluid resistance at the seal. Structurally forms a small gap between the static parts and the rotor to form a "maze". If the "maze" is radial, the axial size is compact, but the radial size is large. If the "maze" is axial, the radial size is compact, but the bearing cover should be cut, and the axial gap should be larger, so as not to die due to the thermal deformation of the axis. The maze seal is quite reliable whether it is lubricating oil and crickets, and the higher the speed, the better the effect.
4. Remove the oil ring density
When the oil is lubricated, the oil that can be leaked along the bearing cover through the centrifugal force of the oil rod on the bearing can be returned to the bearing or oil pool through the oil back hole. The sealing effect is quite reliable. For centrifugal force, the circular speed of the neck must not be less than 5-6m/s. The oil rings are also often used for lubricating fat and lubricating oil in the box in isolation.
Bearing contact -type sealing
The contact seal is the sealing method of the end or lip contact axis of the sulfide synthetic rubber on the steel skeleton. Its seal is better than the non -contact seal, but the friction is huge and the temperature rise is relatively high. In the contact area of lubricating shaft and sealing ring, the same lubricant is usually used as the bearings. The main contact seal is: felt ring seal, leather bowl seal, sealing ring seal, skeleton sealing, sealing ring seal, etc.
1. Freshly seal
Open the trapezoidal groove on the bearing cover, place the fine felt on the rectangular surface in the trapezoidal groove to contact the axis, or use the pressure cover to be tightened, so that the felt ring is compressed and the radial pressure is held on the shaft, so that Achieving the purpose of sealing. This sealing structure is simple, the cost is low, but the sealing effect is poor, and it cannot be adjusted. The wear is severe. It is mainly used for the circular speed of the neck v <4-5m/s.
2. Leather bowl sealing
Put a sealing leather bowl (a leather bowl is made of oil and other materials such as oil) in the bearing cover) directly on the shaft. In order to enhance the sealing effect, the inner ring of the leather bowl is pressed with a ring spiral spring, so that the inner ring of the leather bowl has a strict cooperation with the axis. ~ 7m/s fat moisturizes or lubricating oil lubricating. The disadvantage is that the skin bowl rubber is easy to harden and easy to wear. When using it, pay attention to the direction of the sealing bump of the leather bowl. If you prevent oil leakage, the bumps of the leather wrist should be in the bearings. If the impurities are to be prevented, the bumps of the leather bowl should be the bearings. Essence
3. Sealing ring seal
Sealing rings are made of leather, plastic or oil -resistant rubber, which can be made into different section forms as needed. The 0 -shaped sealing section is round, relying on its own elasticity to press on the axis, the structure is simple, and the disassembly is convenient. The commonly used sealing rings of J -shaped and U -shaped sections, they all have lip -shaped structures. The direction of the sealing lips should be facing the sealing part, which is similar to the direction of the bumpy edge of the leather bowl. When the temperature is high and the speed is high, it is best to seal the lip mouth and install it out of the bearing. The sealing circle sealing effect is better than the felt circle, which can be used for sealing of fat and oily bones. In order to improve the sealing effect, the connection between the neck and the sealing chart is best on the surface hardening (HRC> 40) and polished or polished to enhance the wear resistance.
4. Skeleton sealing
The skeleton seal we often say is the improvement of the leather bowl seal. In order to improve the overall strength of the leather bowl seal, the section is L -shaped and the overall metal lining in the oil -resistant rubber. Life, this sealing is convenient and good for use. It is generally suitable for the round -week speed V <7M/s of the neck. At present, most of the centrifugal pump bearing boxes are sealing of the skeleton.
5.
This is a ring -shaped seal with a gap. Place it in the ring groove of the sleeve. The sleeve rotates with the shaft. On the wall of the inner hole, you can play a sealing role, which is more complicated.
Selection of bearing seal structure
When choosing a bearing confidential seal structure, the main considerations are: lubricant, that is, lubricant or lubricating fat; sealing parts line speed; installation error of the shaft; installation space size and cost.
When selecting the sealing structure, according to different working conditions, you can use a single seal structure, or a combination of a combination of a combination, such as the combined structure of the maze seal+oil groove seal+the oil ring. Dual function of invading.