Harvester development: weight reduction as an important development target
Modern full harvesters for beet and potato crops are highly complex agricultural machines, which carry out the entire harvesting process in a fully automated fashion. The desire for an increase in efficiency has led to machines, as well as storage hoppers, becoming ever larger so that more and more rows can be harvested at the same time. A towed potato harvester of the latest generation has a total weight of over ten tonnes: fully loaded, this actually brings a modern beet harvester to over 60 tonnes total weight.
This weight produces a dangerous conflict of objectives in harvester development. How can weight be reduced without thereby creating a reduction in performance and capacity?
A design engineer in product development for new harvester prototypes is working to solve this conflict. He knows that the customer wants to reduce soil compaction. One solution to this is the use of wider tyres with larger contact areas, but no weight reduction is achieved by this. If an agricultural machine manufacturer wants to reduce the weight of his harvesters, the use of elastomers and synthetic materials is unavoidable. In doing so, advantages result from the use of synthetic materials in the areas of durability and wear resistance, in addition to a saving in weight. Elastomers, however, score with their elasticity, and good sealing and cushioning properties.
Jäger often undertakes joint development of components for harvester prototypes in collaboration with leading harvester manufacturers. Challenges in the production of assemblies and components are more quickly overcome through Jäger’s materials expertise in the rubber and synthetic materials areas, as well as its extensive experience. In-house test stands for the prior checking of materials and assemblies reduce the time required for field tests: Jäger is thus supporting design engineers in bringing innovative prototypes into series production more quickly.
Every individual load-bearing roller reduces the weight – by almost 500 kilogrammes in total
There are up to 200 load-bearing rollers with a weight of 600 kilogrammes built into the filter belt systems of harvesters. Jäger rose to the challenge of redesigning the components, which previously consisted of metal. Following extensive materials tests, a glass fibre reinforced synthetic material in combination with a running surface made from a rubber composite was selected. This elastomer can be adjusted according to the intended purpose and ensures outstandingly quiet running. In addition, it offers the load-bearing roller the required elasticity. Now only the ball bearings are still made of metal. In order to avoid impurities, Jäger has attached a sealing lip on the intake side and a protective cap on the opposing side. Using this selection of materials, a weight reduction to only 550 grammes per load-bearing roller has been achieved. The harvester thus weighs half a tonne less.
Filter belts with rubberised carriers treat the crop carefully
No consumer would buy potatoes whose skin has been damaged. Filter belts with rubberised carriers are therefore of great importance in potato harvesters. The previously used steel carriers are hard, and can cause pressure marks and scraping on the crop. For this purpose, Jäger offers individually adjusted elastomer composites for carriers and transporter belts. Thus as well as a reduction in weight, the potatoes are looked after too.
New development of assemblies with high reliability
In collaboration with harvester manufacturers, Jäger is working on the new development of components to cover the whole life cycle of a product. As well as product properties such as resistance to wear and reliability, this also includes the availability of spare parts. Replacement time is an important criterium, particularly during harvest time, and the expense of fitting also has to be taken into account. Too lengthy fitting times result in expensive machine downtimes.
In every development partnership for the construction of a new harvester prototype, Jäger sees an opportunity for introducing new ideas, and for proving its own materials expertise in such a development project. The management of material properties, with the aid of an appropriate composite, is a factor for success in the development of components. Every assembly whose weight can be reduced, and which is superior to previously used materials with regard to durability, helps in overcoming the conflict of objectives.
If you would like to know more about Jäger’s materials expertise, we recommend that you download our White Paper on agricultural technology. You will find additional information there on the use of new materials in agricultural machines.