Stainless Steel Sheet Metal,Metal Sheet Bending Parts metal fabrication,Customized metal stamping and bending parts Dongguan Shangen Precision Metal Plate Co., Ltd. , https://www.shangenmetal.com
In certain industrial applications, standard bearings often fall short of delivering the level of precision required. This is precisely where extra precision bearings step in. These bearings offer enhanced tolerance and precision, making them ideal for demanding applications that require high speed (measured in RPM) and superior guidance accuracy. There are primarily two kinds of extra precision bearings: deep groove bearings and angular contact bearings.
Deep groove bearings feature full shoulders on both sides of the inner and outer ring raceways, which makes it straightforward to add seals or shields. These bearings can handle radial loads, thrust loads, or a combination of both. They come in numerous sizes, including miniature precision bearings, and are available with various cage types. Known for their versatility, deep groove bearings are among the most commonly used bearing types.
Angular contact bearings, on the other hand, have one complete ring shoulder while the other ring shoulder is either partially or fully removed. This design allows for larger balls, which enhances their load capacity and speed capability. Different cage designs are also available to cater to specific high-speed requirements. Angular contact bearings can support thrust loads or a combination of thrust and radial loads, but they cannot handle radial loads alone. When installed back-to-back or face-to-face, they can support thrust loads in both directions.
Are you interested in learning more about Super Precision bearings? Download our comprehensive guide today!
Angular contact bearings are available in two main types: separable or non-separable. These classifications refer to whether the outer ring assembly can be detached from the inner ring. Separable angular contact bearings are particularly beneficial when installing in a blind hole or when press fits are required in certain applications.
When it comes to closures and cages for extra precision bearings, their primary function is to protect the bearings from internal damage during handling. For extra precision bearings, these closures are typically crafted from materials like Teflon, stainless steel, or other high-performance options. There are two main types of closures for extra precision bearings: shields and seals. Both are designed to prevent contamination and retain lubrication.
Shields are attached to the inner ring, whereas seals are applied to the outer ring. Deciding between these two types depends on the application's priority — whether it's sealing efficiency, speed capability, or bearing torque. Shields offer less efficient sealing but do not increase torque or limit speed. Seals provide stronger protection but restrict operating speed, increase torque, and raise temperatures.
Most bearing assemblies incorporate bearing cages to maintain uniform ball spacing, reduce torque, and minimize heat build-up. Bearing cages come in various designs suitable for both deep groove and angular bearings. The choice of cage is typically based on the specific needs and purpose of the bearing.
Standard precision bearings generally use stamped steel cages. In contrast, extra precision bearings employ cages made from materials such as stainless steel, bronze, or phenolic. These cages offer higher speeds and better load capacities. Cages can meet general-purpose needs as well as specialized requirements like low torque, high speed, lubrication-free operation, and noise control.
All precision ball bearings must adhere to the Annular Bearing Engineers Committee (ABEC) standards, which align with ISO regulations. ABEC standards specify tolerances for crucial bearing characteristics and dimensions, ensuring consistency within the industry.
Parameters addressed in these guidelines include bore roundness and taper, width variation, bore and race runout, and radial runout. Higher ABEC numbers signify tighter tolerances, meaning the higher the number, the better the performance. ABEC 1 through 3 bearings are typically suited for general use, while ABEC 5 through 7 bearings are used in applications requiring greater precision and speed. Bearings from higher ABEC precision classes, intended for stationary housings, have rounder balls and smoother raceways.
However, it's important not to automatically opt for the highest ABEC class. Higher-end bearings can be significantly more expensive, so understanding the exact needs of the application is essential to making the right choice. Often, higher ABEC bearings aren't necessary.
To ensure optimal performance of extra precision bearings, users should verify that their systems are prepared for success. Key considerations include preload and radial internal clearance. It's crucial to carefully assess these elements to guarantee that bearings operate efficiently under favorable conditions.
The bearings must have the appropriate radial internal clearance — the maximum possible movement of the inner ring relative to the outer ring. This is also known as "radial play." Correct radial internal clearance is vital because metals expand; selecting the right clearance prevents metal ball bearings from seizing in their housings when expansion occurs. Bearings lacking sufficient radial play will fail due to interference and binding effects.
Preloading involves removing internal clearance in a bearing by applying a permanent thrust load, eliminating radial and axial play, resulting in a very rigid setup. Preloading helps remove endplay and runout, achieved through methods like spring preloading, axial adjustment, or using duplex bearings.
Duplex bearings are matched pairs of bearings designed to provide built-in preloading. Installed in face-to-face (DB), back-to-back (DF), or tandem (DT) configurations, these bearings counterbalance each other due to their matching preload offsets. This boosts axial and radial rigidity and enables them to withstand bidirectional or heavy unidirectional thrust loads.
Shaft and housing fits are also significant when using extra precision bearings. Users should evaluate the bearing’s intended application before determining the appropriate fit tightness. Looser fits are necessary when axial movement must accommodate spring loading and thermal expansion, or when axial clamping forces are involved. Assembly is simpler with looser fits. Tighter fits are preferable when the application demands heat transfer, vibration impact reduction, or support for heavy radial loading.
Finally, users should decide if extra precision bearings will perform better with grease or oil lubrication. Grease is the typical choice in most scenarios. However, oil should be considered for applications involving higher speeds, as it provides better cooling and creates minimal torque. Oil needs to be replaced more frequently than grease, which lasts longer without maintenance.
Extra Precision Bearings from Emerson Bearing
Emerson Bearing takes pride in being a leading distributor for many renowned bearing manufacturers. We offer extra precision bearings from top brands such as Barden, GMN, Nachi, NTN, and NSK.
Our team of experts can help you find the right bearing for your specific application and requirements. We can assist in evaluating the various factors discussed above — including navigating ABEC standards — to equip you with the knowledge needed to avoid costly mistakes and downtime.
Feel free to reach out to us today to begin the bearing selection process.