NACHI 29428EX Spherical Roller Thrust Bearing 140x280x85 mm

This NACHI range covers 5 spherical roller thrust bearings in the 294 series (4 in the EX design and 1 in the E design), from 60 to 140 mm bore (outer diameters 130 to 280 mm, heights 42 to 85 mm). Select the size from the drop-down: each size has its own bearing number, load ratings and limiting speeds in the Model Details.

The housing-washer raceway is spherical, so the bearings are self-aligning. With a contact angle of about 45° they carry axial load together with a small to moderate radial load, and they take high loads at low to moderate speeds.

Where this product is used

• Crane hooks and lifting gear
• Injection moulding machines
• Large machines with heavy axial load
• Vertical shaft drives and large gearboxes
• Heavy axial load positions at low to moderate speed

Features

• Spherical housing-washer raceway: the bearings are self-aligning, with permissible misalignment of about 2° under general service conditions
• Contact angle of about 45°, so they carry axial load together with a small to moderate radial load
• High load capacity at low to moderate speeds: Ca 350 to 1,410 kN and Coa 915 to 4,350 kN across the range
• Oil lubrication is advised for this bearing type; EX sizes also have a grease limiting speed, while E sizes are rated for oil only
• A minimum axial load of at least Coa / 1000 (N) must always be applied to avoid sliding damage between rollers and raceway

Key specifications

Available sizes

Sizes in the drop-down are bore d x outer diameter D x height T, in mm.

Selecting the right option

EX is the high-capacity design and has both a grease and an oil limiting speed. The E design is rated for oil lubrication only: no grease limiting speed is given. Oil lubrication is advised for both.

Pick the bore first, then check the outer diameter D and height T against the housing space, and check the loads against Ca and Coa with a suitable safety factor. The bearings suit high axial load with some radial load; where radial load is the main load, a radial bearing is the better choice.

Fitting and use

Axial load comes first. The dynamic equivalent axial load is Pa = Fa + 1.2Fr and the static equivalent is Poa = Fa + 2.7Fr, and these apply only while Fr / Fa is 0.55 or less. The static safety factor So must be over 4.

To avoid sliding damage between the rollers and the raceway, the bearing must always carry a minimum axial load Fa min of at least Coa / 1000 (N).

Oil lubrication is advised rather than grease, because of the many sliding surfaces (cage to guide sleeve, roller ends to rib). To get the benefit of the aligning ability (about 2° under general service conditions), leave clearance for the parts around the bearing.

Related products

More from the NACHI spherical roller thrust range: NACHI 29320E spherical roller thrust bearing, 100 x 170 x 42 mm and NACHI 29322EX spherical roller thrust bearing, 110 x 190 x 48 mm. For radial and combined loads with misalignment, see the NACHI spherical roller bearings (radial type).