Polymer bearings replace wearing brass bearings in slurry tankers

• What was needed:pendulum steering axle
• Requirements: Heavy soiling from dirt and slurry, aggressive ammonia cloud affects all components, high stress on all parts during the season due to continuous use
• Industry: Agricultural engineering
• Success for the customer: The susceptible brass bearings were able to be replaced by completely maintenance- 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.

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 made entirely in-house. This includes around 450 tankers manufactured by the family business over the course of the year.
When a slurry tanker is planned, all components are precisely harmonised. This applies to the tyres, the tank and the pump, but also to the chassis. Various axle systems and additional steering support options are available for the chassis. For some years now, a pendulum trapezoidal axle with hydraulic self-steering has been used as standard in the vehicles.
Previously, brass bearings were used in the pendulum steering axles, but they suffered too much wear. During transport and slurry spreading, the bearings were also exposed to heavy soiling and stresses. Lubricated bearings were therefore impractical. 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 in use on a maximum of 100 days a year. At this time, however, the technology must function 24 hours a day, seven days a week without any failures. There must be no technical faults whatsoever.

Four tribologically optimised iglidur Q polymer plain bearings with a diameter of 80mm are now used in the pendulum trapezoidal axle. With plastic plain bearings made from the materials iglidur G, Q and J, a suitable bearing has been found for every position on the slurry tanker. As they are maintenance and lubrication-free, iglidur plain bearings are very resistant to dirt and dust. In addition, the coefficient of friction has been improved, resulting in a longer service life. 
While the wear of the brass bushings was too high, an effective and significantly more robust alternative was finally found with the polymer bearings. The bearings in the axles do not normally come into direct contact with the slurry. But it can splash violently during distribution, so that residual substances are deposited that cannot be removed immediately.
And while the rotation of the steering is low, there is still a particularly high surface pressure. The plastic bearings are perfect for this, as they are highly abrasion-resistant under extreme loads and insensitive to edge loads.
Tribo-optimised polymer plain bearings made from the material iglidur Q have been proving their strength in the steering knuckle of the tandem axle since 1996. Since the lubrication-free bearings have been installed, there have been no more failures.