Sealed needle roller bearing is radial roller that has a diameter which is very small compared to the length of the roller. Go to www.ttv-gmbh.de/dichtungstechnik for learn more about bearings. Both ends of the rollers are modified so as to enhance the contact between the raceways and the bearing.
They are used to prevent stress peaks and subsequently increase the lifetime of the bearing material. They are mostly used in arrangements where radial space is limited.
Why Sealed Needle Roller Bearing
Capacity to carry heavier loads
Despite these rollers being smaller than the general rollers, they have a greater load bearing capacity than the former. This is because their design is made of the most compact material that is hard to break when subjected to torsion.
This makes them conducive for use in both heavy weight and light weight structures. Ideally, the load carrying capacity per mass of this bearing is twice compared to other bearings.
They require little force to operate
These bearings and their assembly cages are made of little mass. This means that they do not need excessive force during operation. This is the reason why they are very useful in machines where tiny inertial force is required. They are mostly used to operate the crankshaft in engines.
They are more rigid
Their small diameter and compactness make them very rigid. This means that their load carrying capacity per unit area cannot be compared to those of ball bearings. Their elastic displacement, when subjected to heavy loads, is smaller. This is why they have the capacity to handle heavy loads.
Good lubrication for oscillatory movement
The needle bearing rollers are preferred where oscillatory movements are involved. Normally when the movements of oscillators fail to overlap the lubricant between the rollers is usually pushed out and therefore makes it inadequate.
This destroys the bearing. For this condition to be prevented from happening, the bearing must have an oscillatory angle that overlaps when the movements are at the minimum.
Compared to cage assembly bearing, needle rollers offer a better rotational accuracy because of their strength and rigidity. This is the other reason why they are preferred for oscillatory movement. Their friction coefficient is sufficient for them to be used in high-speed movement.
Sealed needle roller bearing is usually offered with basic seals of different sizes. The seals are meant to make contact with the shaft and therefore reduce frictional drag. The seal is also used to retain grease or oil within the bearing so as to reduce friction.