We were approached by Europe’s leading Auger drive and trenching equipment manufacturer. One of their customers was demanding increased service life from the largest and most powerful Auger drive gearboxes supplied by our customer which were working in extremely arduous conditions in Siberia.
WHAT WAS THE PROBLEM?
Failure of the gearboxes had been identified as being caused by ingress of the excavated material. This was destroying the environmental seal, with the result that excavated material was being driven up to the main gearbox rotating output shaft oil seal. Once this seal failed the unit lost all gearbox oil. This rendered it inoperable, resulting in costly downtime and the need for back-to-base repair. We were tasked with replacing the current spring energised elastomeric rotary shaft seal with a seal (design and material) that would be more resistant to any ingress of debris, thus increasing service life.
WHAT WE DID
Our technical department worked closely with our customer’s design engineers to gain a full understanding of the limitations and extremes of working conditions being encountered, including temperature and media. Our team realised immediately that while not part of the original remit that focused on the main rotary shaft oil seal, redesigning the environmental seals to stop the ingress of debris was of major importance in increasing the service life of the unit.
Calling on our many years of experience, we identified the best materials to use in each of the seals to give the best wear resistance when working across the required temperature range, then designed the replacement main rotary shaft oil seal. With the combination of material choice and selection of energiser, the new design negated the previous requirement for using hardened running surfaces – saving costs on gearbox components.
UNIQUE SEAL DESIGN
We then focused on the environmental seals, which the customer had identified as the main cause of all failures. We designed a unique seal that would give the longest service life and tolerate the harshest conditions. It would also keep all excavated debris well away from the primary gearbox rotary shaft oil seal.
As always, energiser selection was critical to both seal applications, as the energiser and seal jacket material have to work in unison to create the sealing solution.
A period of testing ensued, designed to abuse the gearbox to ascertain its limits. On completion of testing there were no traces of oil leaking from the unit. Disassembly and removal of the seals showed that no debris had permeated past the single environmental seal. The test had been a success.
DISCOVER THE BENEFITS
Our customer was so satisfied with the results that they decided to add two secondary environmental seals, and also asked us to apply the same principles to a different area of the gearbox and design a replacement for another seal. This seal had never been a problem, but with so much confidence in the new sealing solution provider they wanted us to cover all sealing requirements.
Our customer now has a major marketing advantage over their competition. They are the only Auger drive manufacturer to use high performance PTFE seals in their units, providing increased working life and a reduction in downtime and servicing costs.
We are now working toward implementing their sealing solutions on all of the drive units in the range.