Needle roller bearings have been in existence for some time. They help to reduce frictional force. Typically, they are can be used for lightweight or heavyweight applications. They play a huge role and they should not be ignored.
A rolling element bearing can either be a roller bearing or a ball bearing. Roller bearings are made up of needle, cylindrical, spherical, and tapered bearings. Of all the members of the roller bearing family, needle bearings are the smallest and lightest. This is why they are ideal for use in certain applications especially when reduced weight and space constraint is a consideration. Its length-to-diameter ratio is also relatively high and this is responsible for some of its characteristics. The features of needle roller bearings include:
- It handles large and rigid shafts in certain applications
- Its load capacity is greater than that of single row or roller bearings of similar OD
- Its cost is reasonably lower
- It rolls well even in tight spaces
Full-complement loose needle rollers are the most economical type of needle roller bearings. It is often used in applications where the outer raceway is a hardened and ground gear bore. When fully assembled and applications are met, a small cross sectional bearing can be formed by a full complement of rollers. This bearing usually has a high load capacity. If you analyze its cost for each pound of capacity, it is the most reasonable and cheapest. There are different end configurations of needle rollers and it is used in applications such as planetary gears, U-joints, and constant-mesh gears.
Drawn-cup needle roller bearings
They are relatively easier to handle and install. It has a case-hardened outer shell that doubles as the outer raceway. This outer shell is made from low-carbon strip steel. This bearing is highly economical because it does not require subsequent machining. It is used in applications such as pilot bearings, pulley support, gearbox shaft support, and gear pumps.
Needle roller and cage assemblies
It is a cage assembly design with several advantages. Firstly, it gives control over radial internal clearances. Also, it helps to ensure the load is appropriately distributed between raceways and rollers. Another advantage it has is that it does not tolerate misalignment of the shaft and it can operate very well in high-speed conditions. It is widely used in planetary gears, connecting rods, idler gears, and constant-mesh gears.
Its outer ring is machined, thick, and well-grounded. It has the ability to handle overload and shock. The cross-section of the outer ring permits mounting in a split housing. It also has a cage that shields the rollers. Also, it has the ability to handle high speed and misalignment. It is used in the steering gear, heavy machines, and hydraulic pumps.
Thrust needle roller and cage assemblies
It has the ability to carry an axial load in limited spaces. It holds needle rollers with a hardened steel cage. Their load capacity is impressive and they deal with friction expertly. It can provide low friction in a limited amount of space, and this explains why it is generally used in automatic transmissions.
It is often used on track-type equipment. It consists of a thick outer ring. This outer ring can handle shock loads and withstand heavy rolling which is common for such application. Mounting arrangement designs vary. Actually, there are two types. For a clevis mounting, you can make use of the yoke type. The integral stud type is ideal for cantilever mounting. Track rollers are used in applications like machine ways, cam followers, and mast rollers.