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More Radial Bearing Designs

series at the cost of increased overall dimensions.

Tapered Bore Inner Rings

Bearings with heavy section inner rings are also available with a tapered bore, see series BT-L(figure 6). The taper is 1:8 or 1.5" per ft on diameter. There are 2 main reasons for using a tapered bore bearing: •To prevent rotation between inner ring bore and shaft. •To control the diametral clearance of the bearing assembly. As the inner ring is forced up the tapered pin, its outside diameter expands effectively reducing the diame- tral clearance. CAUTION: Reducing the operating clearancebelow 0.001" (0.025mm) may increase bearing friction and wear rate. Asubstantial thrust force in the direction of the large end of the taper may cause additional inner ring expansion which could lock up the bearing. high loads, pin deflection may become a problem.

RBC QuadLube

®

Design

With few exceptions, steel-on-steel spherical plain bearings used in dynamic applications must be relubricated periodically. To be effective, the grease must penetrate into the contact area between inner and outer ring. If a bearing is subject to a unidirectional load, it must be unloaded during relubrication or only a minimal amount of grease will ever reach the contact area. Most of the lubricant will accumulate in the unloaded zone and eventually exit without benefiting the bearing service life.The QuadLube
® design solves the lubricant flow problem of bearings where the load acts always in the same direction. The additional circular grooves on the spherical diameter of the inner ring allow grease to flow into the contact area even with the bearing under load. The grooves help to collect wear debris which is purged from the bearing during a subsequent relubrication cycle. CAUTION: The actual tilt angle of a bearingassembly may be limited by the design of
Tapered Bore

Heavy Section

Cylindrical Bore In a typical bearing application, the inner ring mountson a shaft and its face abuts against a shoulder. If the bearing must support significant thrust loads, the shoulder diameter should match the outside diameter of the inner ring at the face to minimize contact pressure. See the catalog pages for this dimension. Atilting outer ring will eventually make contact with this shaft shoulder, which defines the bearings maximum tilt angle (figure 4).
Figure 6:Heavy Section Inner RingCylindrical vs.Tapered Bore

Extended Inner Rings

CAUTION: Spacers and inner ring extensionsincrease the distance between pin supports. At For applications with substantial outer ring tilt, forexample yoke supported rod ends of some hydraulic cylinders, RBC offers radial bearings with extended inner rings (figure 7). Using a bearing with an extended inner ring obviates the need to add separate spacers to the bearing assembly to create the axial space required by the outer ring housing.
a dd1 Figure 4:Maximum Tilt Angle Extended Inner Ring Standard Inner Ring surrounding components. To increase the tilt angle of a standard bearing, thewidth of the inner ring must be increased. But simply increasing the width is not sufficient because there would be no inner ring face left if we did not also reduce the inside diameter of the inner ring. These inner rings with greater width and wall thickness form the heavy section series BH-L(figure 5). For a given shaft size, the heavy section bearings have greater misalignment capabilities and a greater load carrying capacity compared to the standard
Figure 7:Standard vs.Extended Inner Ring

DuraLube™ Maintenance-Free Bearings

RBC offers maintenance-free bearings consisting of a chromium plated inner ring, an outer ring with a bonded PTFE liner and seals. The liner provides excellent load bearing capacity and a low wear rate (figure 8).
PTFE Liner Bonded to Outer Ring Outer Ring Standard Inner Ring Heavy SectionInner Ring Figure 5:Standard vs.Heavy Section Inner Ring Figure 8:Maintenance-Free Bearings 51