NACHI 51222 Single Direction Thrust Ball Bearing 110x160x38 mm

The NACHI 51222 is a single-direction thrust ball bearing (512 series) with a flat back-face housing washer. It measures 110 x 160 x 38 mm (bore x outer diameter x height) and carries a basic dynamic axial load rating of 152,000 N and a basic static axial load rating of 450,000 N. Limiting speed is 1,200 rpm on grease and 1,900 rpm on oil, and the mass is 2.57 kg.

A thrust ball bearing is a shaft washer, a housing washer and a ball and cage assembly running in a groove in each washer. It carries axial load in one direction only and cannot carry any radial load, and it is not suited to high speed running.

Where this product is used

• Vertical shaft pumps, gearboxes and drives
• Screw jacks, lifting screws and clamps
• Turntables, rotary tables and swivel joints
• Machine tool tailstocks and spindle thrust positions
• Low speed, axial load positions in general machinery

Features

• Single-direction thrust ball bearing: carries axial load in one direction only, with a ball and cage assembly running in a groove in each of the shaft washer and the housing washer
• Carries axial load only and cannot carry any radial load, so a separate bearing has to locate the shaft radially
• Flat back-face housing washer for a flat housing shoulder; it does not permit any angular misalignment between shaft and housing
• Not suited to high speed running, because centrifugal force throws the lubricant out; limiting speeds for grease and oil are listed
• Basic dynamic axial load rating 152 kN and static 450 kN; limiting speed 1,200 rpm on grease, 1,900 rpm on oil

Key specifications

Selecting the right option

Ca is the basic dynamic axial load rating, used for life calculations on a rotating bearing, and Coa is the static rating. Check the axial load against both and apply a suitable safety factor.

This is a single-direction bearing. Where axial load acts in both directions, a double-direction thrust ball bearing is needed.

Fitting and use

Axial loads only. The bearing cannot carry any radial load, so the shaft needs a separate bearing to locate it radially. The flat back-face housing washer needs a flat, square seat and does not permit any angular misalignment between shaft and housing.

On a horizontal shaft a minimum axial load must be applied so the balls roll rather than skid. The minimum axial load Fa min (N) is the larger of K x n² and Coa / 1000, where K is the minimum axial factor for the bearing (x 10⁻⁶) and n is the speed in rpm. On a vertical shaft the weight of the shaft often exceeds this, and an opposing external axial load reduces the load that acts on the bearing. For this size Coa / 1000 is 450 N and K is 1010 x 10⁻⁶.

The shaft washer and housing washer have the same outside diameter (D1 and d1 in the table), so the housing bore needs a step to clear the shaft washer. Fit the shaft washer (the one with the smaller bore) to the shaft and the housing washer in the housing.

Related products

More from the NACHI thrust ball range: NACHI single-direction thrust ball bearings, 511 / 512 / 513 series, 10 to 120 mm bore (46 sizes), NACHI inch series O thrust ball bearings, 15.875 to 57.15 mm bore (10 sizes), NACHI 51128X thrust ball bearing, 140 x 180 x 31 mm and NACHI 51208 thrust ball bearing, 40 x 68 x 19 mm. For heavier axial loads, or where some radial load or shaft misalignment has to be accommodated, see the NACHI spherical roller thrust bearings (60 to 140 mm bore).