Cross-fertilizing seal technology from Automotive to Agri-machines


Koyo Bearings, a division of JTEKT Corporation has achieved significant improvements in muddy water resistance by developing new seals for ball bearings used in agricultural machinery that are normally operating in very harsh environments. This technology was originally developed for use in automotive hub units and is now also available for the agricultural sector.

Koyo’s automotive bearing technology, which has been developed for road conditions that vary strongly in all countries across the world, will now contribute to the stable operation and reduced maintenance frequency of agricultural machinery, as well.

Background of the development

Tractors and planters (the attachment to a tractor for sowing seeds) are normally used under harsh, muddy water conditions and it has been taken for granted, so far, that they should be replaced or overhauled after a relatively short life cycle. Recently, in order to meet the new, more stringent needs of agricultural machinery manufacturers to provide bearings that are resistant to breakage, Koyo has developed a ball bearing with high muddy water resistant seals by applying the same seal technology used in automotive wheel hub units.

Results after 400 hours of muddy water test

The left bearing clearly shows muddy water intrusion after removing the conventional seal. The right bearing shows no muddy water intrusion after removing the newly developed special seal.

Features of the new product

Conventional sealed bearings for agricultural machine attachments have two radial lips for improved mud resistance, but our new product has an additional axial lip in addition to the radial lip to optimize the geometry, reduce torque and achieve high sealing performance. The picture on the right shows the new 3-lips version with shape optimization and a shield labyrinth, resulting in more than doubling of the mud resistance.

The vibration level is a clear indicator of the performance deterioration of the bearing, due to muddy water ingress. As can be seen in this evaluation test chart, the vibration level increases significantly over time when the conventional seal is used. Based on such bench tests we can say that the muddy water resistance of the seal is expected to increase with at least a time-factor 2.

Optimized seal

geometry reduces torque by 40%

An additional benefit of the newly developed seal is that the rotation torque is reduced by

40% which provides a positive contribution to better fuel consumption and therefore to reduction of CO2-emissions.

Availability of this product

This product is in serial production for a large Agricultural machine maker since October 2020 and the related types/sizes can be made available for other customers, as well.

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This article is published in BearingNews September 2021 issue