By replacing solid spherical roller bearings on a vehicle bodywork washer conveyor belt drive with split spherical roller bearings and matching housings from Schaeffler, a car manufacturer in Spain has significantly reduced the time it takes to replace damaged bearings, resulting in reduced maintenance costs and reduced downtime of the washer plant.
With 11,000 employees and sales revenues of around EUR4.8 billion, the Spanish car maker produces around 400,000 vehicles per year. Car bodyworks are cleaned in a bodywork washer prior to being painted. The service lives of the original (solid) spherical roller bearings installed on the washer conveyor return unit were reduced by the harsh operating conditions. Each time a damaged bearing in the conveyor belt drive needed replacing, production had to be stopped for at least 4–5 hours while the bearings were dismounted and replaced. In order to reduce these unplanned shutdowns, the customer asked Schaeffler to simplify the replacement of the bearings.
The most effective approach was to replace the solid spherical roller bearings with Schaeffler’s split spherical roller bearings and matching housings. Due to their special design, these bearings are much easier to mount. The use of split spherical roller bearings reduces the time it takes to replace bearings, particularly in areas that are difficult to access such as shafts with multiple supports. In a split bearing, the inner ring, outer ring and roller-and-cage assembly are split into two halves that are clamped together using screws. A cylindrical bore provides direct mounting onto the shaft, which means the bearings typically offer high thrust loads and dynamically compensate for any misalignment. Also, by using a split version of the bearing, many stages of the mounting and dismounting process are omitted. This means that downtimes – and any associated costs – are reduced significantly.
Convinced by a product presentation, the customer asked Schaeffler to replace the bearings and housings in the car bodywork washer conveyor belt drive. Experienced fitters from Schaeffler replaced the conventional bearings with special plummer block housings fitted with lip type seals and split spherical roller bearings. In addition, FRM140/12.5 bearing rings from Schaeffler were installed at the locating end, which meant that it was only necessary to modify the washer machine bed in order to adjust the shaft axis to the correct reference height.
Replacing the bearings now requires much less time – 30 minutes rather than 4–5 hours – resulting in significantly reduced washer downtime and increased washer availability. Depending on the car model, production losses resulting from a 4–5 hour bearing replacement can be as much as 500 bodyworks. By replacing these bearings with split spherical roller bearings, production losses are reduced to 180 bodyworks.
As well as reducing the time required to replace (i.e. dismount and mount) the bearings, split spherical roller bearings from Schaeffler are also easy to stock due to their modular design; the same housing size is suitable for different shaft sizes.
Typical applications for split spherical roller bearings include belt drives, paper machines, mixing and stirring plant, conveying equipment, roll mills, converters, crushers, rotary kilns, fans, ventilators, drive and transmission shafts. In many applications, the spherical roller bearing is mounted to the shaft in such a complex arrangement that when the bearing needs to be replaced, it is also necessary to remove all the adjacent components. This results in increased downtime and complex additional tasks such as the removal of gears, clutches and other drive units.
For more information on split spherical roller bearings from Schaeffler, please visit www.schaeffler.co.uk.