Sealed Bearings Selections-Seals and Shields Available

The Reali-Slim® thin section bearings product line consists of a family of seven open and five sealed series of thin section bearings ranging in bore diameters from 1.000 inch to 40.000 inch. Series range from .187 x .187 inch to 1.000 x 1.000 inch in cross section. Open bearings are available from stock in three configurations (Types A, C & X). Stock sealed bearings are available in Types C & X only.

When required, these bearings can be quickly modified to have special clearances, preloads, lubricants, separators and other features to meet the most demanding application requirements. In addition, the Reali-Slim® product line can be quickly modified to obtain corrosion resistance by applying Endurakote® thin-dense chrome plating. When assembled with 440C stainless steel balls, this modification makes up the basis for Kaydon's Endura-Slim series of bearings that provide corrosion protection equal to or better than a full 440C stainless steel bearing.

Reali-Slim® thin section sealed bearings are available with various separators to space the rolling elements uniformly and prevent contact between them. Separator types available include: continuous ring "snap-over pocket," continuous ring circular pocket, formed wire, toroid, Teflon spacers, and spacer ball separators.

Sealed thin section bearings summary

To realize the full benefits from anti-friction bearings, it is important to keep them clean and well lubricated. Seals and shields properly designed and mounted help to accomplish this. In the Kaydon thin section bearings catalog, these terms have the following definitions:

Seal--a contacting closure between the stationary and rotating members, for retaining lubricant within and excluding foreign material from the bearing. Seals are retained in the outer race and make positive contact with the inner race.

Shield--a closure for the same purpose as a seal but without positive contact.

A seal is more effective, but requires more turning effort (torque), generates more heat, and as a result, has a lower speed limit than an open or shielded bearing.

Available illustrations are examples by which Reali-SlimŽ bearings may be sealed or shielded, either integrally or externally. The lubricant and lubrication systems, torque requirements, speed, and operating environment will influence the choice.

Integral seals and shields offer a very compact overall design with the additional advantage of protecting the bearing before, during and after installation. Figure 9 shows a double sealed Reali-SlimŽ bearing, available from stock in the JU series. In this case, adding shields and seals requires an increase in the width of the bearing. Page 12, Position 2. In the case of JA, JB, and JG double sealed Reali-Slims, the bearing width is the same as that of the open bearing. Illustrated in Figure 10 is a double Lami-Seal® bearing. Shown in Figure 11 is a double Lami-Shield® bearing for use where a shield will suffice or is required due to torque limitations or speed.

Note: Sealed Reali-Slim® bearings are pre-lubricated with a general purpose grease. Operating conditions (i.e. time, temperature, speed, environment) may result in premature grease breakdown. Grease options are available upon request.

Where weight and space are at a premium, and a seal or shield is required on one side only, single sealed or single shielded bearings as shown in Figures 12, 13 and 14 may be supplied. Figure 15 shows a BUNA-N™ lip-type seal ring available in a variety of cross-sections compatible with the Reali-SlimŽ bearing series. While this is a very effective seal, torque is substantial and speeds must not exceed 1000 feet per minute if continuous.

Figure 16 shows a felt seal ring which is suitable for higher speeds and can be made from commercially available strip stock by bonding the ends with solvent resistant glue. Many grades of felt are readily obtainable for experimental determination of the best compromise between torque, heat, wear, and seal effectiveness.

If grease lubrication is used and torque is not critical, a very effective shield is that shown in Figure 17 where annular grooves are cut in the housing shoulder and clamp plate and filled with grease.

When a separate shield is required, washers made from precision flat stock are ideal, as shown in Figure 18. They serve well where weight limitations are strict. Whether or not integral seals or shields are specified, bearings must be isolated from hostile environments and debris.