IKO TLA2520UU Shell Type Needle Roller Bearing, Seals Both Sides, 25 x 32 x 20 mm

IKO TLA UU shell type needle roller bearings are the metric series with seals on both sides (UU), caged, with no inner ring. This page lists 15 sizes: 12 to 40 mm shaft, 18 to 47 mm outside diameter and 16 to 20 mm wide.

Shell type needle roller bearings are lightweight with large load ratings. The outer ring is drawn from thin special steel plate, carburised and quenched, and gives the lowest sectional height of the needle roller bearings. They are press-fitted into the housing, so no fixtures for axial positioning are needed, and suit mass-produced products where economy matters. The outer ring is wider than in the open TLA series, and the bearing is supplied prepacked with grease.

The shaft runs directly on the needle rollers. No inner ring is listed for the sealed shell type, so ask AIMS if the shaft cannot be hardened and ground.

Where this product is used

• Mass-produced assemblies that need an economical bearing
• Positions where dust may reach the bearing
• Press-fit housings with no axial fixing

Features

• Shell type caged needle roller bearing with seals on both sides, metric series (TLA, UU), 15 sizes
• Shaft 12 to 40 mm, outside diameter 18 to 47 mm
• Thin drawn outer ring with the lowest sectional height of the needle roller bearings, pressed into the housing with no axial fixing
• Seals on both sides (UU), special synthetic rubber, supplied prepacked with grease
• Basic dynamic load ratings 6.42 to 16.7 kN, static 7.49 to 33.7 kN
• Allowable rotational speed 4,500 to 14,000 rpm (grease lubrication)

Key specifications

Available sizes

No inner ring is listed for the sealed shell type; ask AIMS if you need one. Fw is the roller set bore diameter, D the outside diameter and C the width; C and C0 are the basic dynamic and static load ratings, and speed is the allowable rotational speed for grease lubrication.

Selecting the right option

Choose the size with the Outer Diameter and Width (mm) options. The shaft diameter and width are also in the model number and in the sizes table.

The UU in the model number means seals on both sides. The open version of the series has no UU and is on the TLA page.

Other shell type series: TLA UU has seals on both sides. The open standard series is TLA and the heavy duty series is TA. For inch shafts see BA and BHA.

Fitting and use

For a steel or cast iron housing, use a shaft tolerance of h6 and a housing bore tolerance of N7. The shaft and housing limits for each size are in the specifications under each variant.

The shaft acts as the raceway: its surface hardness should be 58 to 64 HRC and its surface roughness 0.2 µmRa or less. Where the shaft cannot be hardened and ground, use an inner ring (ask AIMS about a ring for the sealed type). The required static safety factor is usually more than 3.

Press the bearing gently into the housing with a suitable tool, with the marked end surface up. The outer ring is thin, so never strike it directly with a hammer. It is fitted with interference, so it does not need axial fixing.

These bearings are supplied prepacked with grease. The allowable rotational speed in the tables applies to grease lubrication. None of these models has an oil hole. An oil hole version of the shell type is made by adding OH to the end of the number; ask AIMS if you need one.

Related products

Parts that go with this range: TLA: the open standard series; TA: the heavy duty metric series.