felt seal protects bearing points from dirt

Maize as far as the eye can see: It is a slightly cloudy day in a maize field in Hungary when a Terra Variant agricultural machine slowly appears on the horizon. Behind the cab is a large slurry tank in which the fertiliser for the maize field is carried. Instead of spreading the valuable organic fertiliser superficially and thus accepting nutrient emissions, the Terra Variant pulls an impressive machine behind it at a speed of ten kilometres per hour: SecatFlex SL is the name of the slurry hoe attached to the vehicle. Its dimensions are impressive: the machine is 7.5 metres wide and weighs 2,300 kilograms.

The SecatFlex SL is used to incorporate the slurry into the upper soil horizon of the field. First, two hoeing coulters loosen the soil, then the slurry enters the soil via a hose. The third hoeing coulter then covers the two fertiliser ridges with soil so that there is no mixing with the slurry. Spread across the entire working width, a total of ten of these hoeing elements operate at 75-centimetre intervals, hoeing between eleven rows of plants at the same time. The direct incorporation into the soil means that valuable nutrients are retained and there is no noticeable pungent ammonia odour after spreading. Of course, it is not only the fertiliser that has to be treated sustainably in agriculture, Holmer also places high ecological demands on its own vehicles and machines. For this reason, the manufacturer decided to install lubrication-free igus® plain bearings in the design of the SecatFlex SL.

Where movement must be guaranteed, high demands must be met under the adverse conditions in agriculture. Joints in agricultural machinery often require lubrication to ensure friction-free operation. The disadvantage: metal bushings are used in conventional applications, which require good lubrication. This requires large quantities of grease, which is delivered to the bearing via lubrication points. It is often not possible to seal the lubricated components properly so that harmful grease escapes. This is a particular problem in agriculture, as farmers should avoid environmental pollution from lubricants at all costs. "We were therefore looking for an application with low lubricant requirements for the SecatFlex SL," explains Andreas Erl, who was responsible for the development of the slurry hoe at Holmer Maschinenbau. From their existing contact with igus®, Erl and his team were quickly introduced to the special plain bearing iglidur® SG03 to their attention. "The SG03 kills two birds with one stone and is therefore so suitable for Holmer," says Thomas Weber, who supports Holmer as a technical sales consultant at igus®. Because like all iglidur® plain bearings, the SG03 is lubrication-free, as no external lubrication is required. At the same time, it offers a felt seal, which seals the bearing points against dirt and dust. This is a great advantage, especially in agriculture. The joints are often exposed to extreme loads and must offer a high degree of reliability. In laboratory tests, igus® has achieved a service life of up to 50 times longer for the plain bearing with felt seal compared to conventional solutions. In addition iglidur® SG03 impressed in the tests with its wear resistance.

The fact that Holmer Maschinenbau has once again chosen igus® components for the SecatFlex SL is due to the long-standing cooperation between the two companies. "We've actually always used igus® bushes," says Andreas Erl. In the meantime, the practical test has shown that Holmer has chosen the right solution. The first pre-series machine is on the road in Hungary, where an area of 1,000 hectares of maize is being fertilised.