Plummer block housing increases bearing operating life

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Plummer block housing increases bearing operating lifeSchaeffler has developed a new plummer block housing for spherical rolling bearings, which increases the operating life of the bearings by up to 50 per cent compared with conventional plummer block housings.

The new FAG SNS plummer block housing from Schaeffler has been completely redesigned, providing numerous technical advantages to users, including more even load distribution on the bearings, resulting in an extended operating life. Schaeffler has also optimised the design further, resulting in a housing that is not only more cost effective to manufacture, but also easier to mount and dismount. Manufactured from high-quality, spheroidal graphite cast iron as standard, the housing ensures a high level of robustness and operational reliability. Other benefits include improved lubrication and condition monitoring of the bearings, as well as increased application flexibility and a significant reduction in overall cost of ownership.

Also, due to the introduction of new, industry-standard mounting arrangements and dimensions, the housing can be installed as a direct replacement (retrofitted) for a wide variety of conventional plummer block housings. The patented design of the FAG SNS plummer block housing distributes the load on the bearings more effectively (uniformly) than previous and alternative housings.

Using its in-house developed bearing design, calculation and simulation software, Bearinx, Schaeffler is able to analyse different housing designs with various combinations of bearings, enabling the optimisation of the complete system (i.e. housing and bearings). By introducing some subtle geometrical changes, including a small arch-shaped cutaway at the bottom centre of the housing, the load on the bottom roller (at the apex, 180 degrees) is now distributed more evenly across two or three rollers. By spreading the load from the shaft across a greater number of rolling elements, the operating life of the bearing is increased by up to 50 per cent.

Further design changes have resulted in improved bearing lubrication, mounting and condition monitoring – which together contribute to a significant reduction in the total cost of ownership.

A lubrication bore with a longer groove has now been added to the inside of the upper section of the housing. This means that different bearing types installed in each bearing position can now be supplied with sufficient lubricant at all times. The lower section of the housing still contains grease outlet bores, which allow for the removal of used or superfluous grease when relubrication is carried out.

FAG SmartCheck

To enable improved condition monitoring of the bearings, connections are now provided on both sides of the housing as standard for Schaeffler’s FAG SmartCheck condition monitoring device. However, if these two connections are not accessible, a centre mark in the upper section of the housing indicates the optimum mounting position for condition monitoring.

Schaeffler can also supply the housing with connections for its new Concept 8 automatic lubrication system.

To make mounting even easier, centre marks that indicate the bearing centre line and shaft are provided in the lower section of the housing, which enables fast alignment of the housing. The lower section of the housing also incorporates high-precision, machined locating surfaces. These are raised and so allow the use of ledges to achieve precise alignment. Once it has been aligned, the housing can be quickly replaced if required.

Bevels, small surfaces and an upper housing section that covers the lower housing section, eliminate potential collection points for fluid and contaminants, ensuring that these drain off naturally, reducing the amount of cleaning required. A variety of seals are available, which enable the bearings to operate in harsh environments such as mining, quarrying, mineral processing, food and beverage processing, and applications in which the bearings must perform reliably over extended periods in harsh, remote locations.

Rolling bearings of different diameters and widths can be installed in the new SNS plummer block housing. The bearings are moveable and so function as non-locating bearings. Suitable bearings include the 222, 223, 230, 231, 232, and 240 series. The FAG SNS housings can be used as direct replacements for a wide range of conventional housings.

For more information on Schaeffler’s FAG SNS plummer block-housed bearings, please email , or visit the website at

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