Image Credit: ABT Bearing | Applied Industrial Technologies | SKF/North America

Insert bearings and wide inner ring bearings are used for mounting on shafts without the need for shoulders, locknuts, or adapters. The bearing is locked in place through setscrews or a locking collar. The inner ring usually extends on both sides of the bearing to provide extra shaft support. 

How Insert Bearings Work

   
Generally, insert bearings are standard radial bearings that have been adapted to fit into a housing.  Although they are generally sold with the housing, these bearings may also be purchased as stand-alone products to use as replacements.  While standard radial ball bearings must be pressed into a machined shaft, using special installation tools, insert bearings can be slip fit directly onto the shaft.  However, insert bearings are typically mounted onto shafts that are slightly smaller than the bearing bore diameter. This loose fitting necessitates a locking device to hold the bearing securely in place. The inner ring of the bearing is extended to one side to accommodate the locking device. In addition, the width of the insert bearings inner ring may vary according to the type of the bearing. 

How Wide Inner Ring Bearings Work

    
A related style of insert bearings is the wide inner ring bearing. The wide inner ring, or double extended inner ring insert features an inner ring that extends beyond the width of the outer ring on both sides of the insert. The extension on one side accommodates a heavy-duty seal. The other side is extended even further to accommodate both a heavy-duty seal and the locking device.  Wide inner ring insert bearings also distributes the load over the larger surface area created by the wider inner ring. These bearings are generally used for heavier duty applications.  Some manufacturers create inserts that fall between narrow and wide inner ring inserts. By combining features of both they create a more economical "will-fit" that is neither a true narrow or wide inner ring.

Additional Specifications

   
In addition to allowing motion and support, many insert bearings are designed with seals to provide protection from contamination and as a retainer for lubricant.  They may be designed with single or double seals, or single or double shields to prevent the ingress of dirt.  However, open bearings, which lack shields or seals are also available. Open bearings offer no protection from contamination or lubricant containment, but have higher maximum speed capabilities than bearings with seals or shields.

Related Standards

• BS ISO 9628 - ROLLING BEARINGS - INSERT BEARINGS AND ECCENTRIC LOCKING COLLARS - BOUNDARY DIMENSIONS AND TOLERANCES
• JIS B 1558 - ROLLING BEARINGS - INSERT BEARINGS AND ECCENTRIC LOCKING COLLARS
• ADS AS2074 - BEARING INSERT - PILOTS SEAT RAISING GEAR