Polymer bearings replace wearing brass bearings in slurry tankers

Profile

• What was needed: tribologically optimised iglidur® Q polymer plain bearings
• Requirements: Heavy pollution from dirt and slurry, aggressive ammonia cloud affects all components, within the season high stress on all parts due to continuous use
• Industry: agriculture
• Success for the customer: The vulnerable brass bearings could be replaced by completely maintenance-free and lubrication-free iglidur plain bearings, the new bearings are robust, insensitive to dirt and dust and have a longer service life due to their low friction properties

Slurry tankers from Zunhammer GmbH distribute nutrient fertiliser evenly and economically on agricultural land. Nutrients are registered with an NIR sensor that continuously picks up information about the composition of the slurry from a slurry pipe.

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Problem

The family business Zunhammer GmbH exclusively manufactures customised agricultural vehicles. Whether tyres, distribution or docking systems, pumps or working widths - as a rule, these are customised solutions, completely from their own company. Over the year, this also includes around 450 tankers that the family business manufactures.
When a slurry tanker is planned, all components are precisely matched to each other. This applies to the tyres, the tank and the pump, but also to the chassis. Various axes systems and additional steering support options are available. For some years now, a pendular trapezoidal axis with hydraulic self-steering has been used as standard equipment in the vehicles.
Previously, brass bearings were used in the pendulum steering axes, but they had too much wear. During the transport and spreading of the slurry, the bearings were also exposed to heavy contamination and stress. Therefore, a lubricated bearing was not practical. In addition, there is always a cloud of ammonia hovering around the vehicles, which also affects all components.
As agriculture is dependent on the weather, it is not possible to drive to the field in all weathers, so a slurry tanker is only used for a maximum of 100 days a year. During this time, however, the technology must function 24 hours a day, seven days a week, without failures. There must be no technical faults whatsoever.

Solution

Four tribologically optimised iglidur Q polymer plain bearings with a diameter of 80 mm are now used in the pendulum trapezoidal axis. With polymer plain bearings made of the materials iglidur G, Q and J a suitable bearing was found for every point of the slurry tanker. Due to the freedom from maintenance and lubrication, iglidur plain bearings are very insensitive to dirt and dust. In addition, the coefficient of friction could be improved, resulting in a longer service life. 
While the wear of the brass bushings was too high, an effective and significantly more robust alternative could finally be found with the polymer bearings. The bearings in the axle do not normally come into direct contact with the slurry. But it can splash violently during distribution, so that residues are deposited that cannot be removed immediately.
And while the rotation of the steering is low, there is still a very high surface pressure. The plastic plain bearings are perfectly suited here, as they are highly abrasion-resistant under the most extreme loads and insensitive to edge loads.
Tribo-optimised polymer plain bearings made of the material "iglidur® Q" have been proving their strength in the steering arm of the tandem axle since 1996. After the lubrication-free bearings were installed, there haven't been any failures any more.

In addition to the weather, the vegetation must be suitable for spreading the slurry. For this reason, the tankers only go out on a maximum of 100 days a year. At the high season, however, they are then often on duty 24 hours a day, seven days a week.

Heavy duty polymer bearings made of iglidur Q are used in this pivoting extension arm in agricultural machinery. The lubrication-free machine components have been proving their worth for many years. With the brass bushings used in the past, the wear was too great.