Needle bearings (also called needle roller bearings) employ small cylindrical rollers to reduce friction between moving components. There are various designs to meet various application needs.
Drawn cup needle bearings, one-way drawn cup needle bearings, entity bushed needle roller bearings and retainer assembly bearings are some of the most frequently encountered types of needle bearings. Each model offers its own special outer ring structure to secure roller placement while providing optimal lubrication conditions for maximum performance.
Size
Needle roller bearings have an advantage over other bearing types by virtue of their smaller cross section and lower starting and running torque, which translates to reduced power loss and greater mechanical efficiency.
Needle bearings offer many advantages over conventional ball bearings, including their compact design that makes them suitable for applications with tight spatial constraints or where weight reduction is a top priority. Furthermore, needle bearing can support axial loads which apply parallel to their axis of rotation making them an effective option for multidirectional applications.
Drawn cup needle roller bearings without inner rings have the thinnest outer ring among rolling bearings, while full complement designs support high speeds. Machining accuracy and heat treatment hardness of shaft or shell hole should match those of bearing raceway to ensure high loads and long service life; for more insight on choosing and maintaining needle bearings please see our How to Maintain Needle Bearings guide.
Load Capacity
Needle bearings feature long, thin cylindrical rollers with high length-to-diameter ratios that enable them to support relatively heavy loads for their small size. Ideal for applications involving high radial pressure at low rotational speed such as gear pumps, motors, compressors and power transmission equipment where friction reduction and wear reduction is a priority, they reduce power consumption while increasing mechanical efficiency while decreasing wear on parts such as motors or compressors.
Needles bearings typically feature outer rings constructed from vacuum-degassed, carburized steel with precision ground and hardened cages designed for strength and wear resistance, providing strength while simultaneously supporting their heavy load capacity and providing compact structures easily installed with press fits – no snap rings or housing shoulders necessary!
Needle and cage assemblies combine features to offer both high limiting speeds and loads in small, simple-to-mount designs. They consist of an outer ring with full complement of needle rollers mounted axially onto a shaft via press fit mounts, along with an assembly of needle cages that encase these rollers for mounting to the shaft using press fits.
Temperature
Needle roller bearings can withstand high loads in an extremely compact size, unlike ball bearings. Unfortunately, this increased load can produce heat which increases friction between rolling elements and mating surfaces and shortens their service life significantly – for this reason it is vital that suitable lubricants be applied when operating needle roller bearings.
If you use an incompatible lubricant with your bearings, this could lead to pitting, extra heat production and increased friction, all which reduce performance and shorten service life. Therefore, regular inspection is key to ensure they’re properly lubricated.
Needle Bearings, which come both sealed and unsealed designs, offer an ideal solution for many different applications. Their durability, compact size, ability to support both radial and axial loads simultaneously and cost-efficiency often makes them the superior choice when used together compared to separate bearings for these purposes. Furthermore, they’re easy to mount and maintain – perfect for demanding environments!
Flexibility
Needle roller bearings may not be widely known, but they play a crucial role in many mechanisms. Their needle-shaped rolling elements housed in cages provide smooth radial loads without creating unnecessary friction or heat.
Needle bearings can operate at high speeds while being easily disassembled for cleaning and inspection, without requiring much lubrication to reduce friction between mating surfaces.
The most widely used form of needle bearings is the drawn cup variety, featuring a deep but thin-walled outer ring with an open or closed bore that can also be capped to fit over a shaft. Bearings without inner rings may also be available for smoother operation; to achieve optimal performance, however, the hardness, machining accuracy, and surface quality of shaft or housing holes must correspond with that of raceways in needle bearings – this ensures they fit securely for easy installation.
