Isomag Bearing Seals

This Product Spotlight looks at a long-term solution to gear lubrication leaks.

submitted by Isomag

There are few things more troublesome for building owners and occupants than an elevator that is out of commission. But why do elevators stop working? Are lift equipment gear drives leaking oil frequently the cause of elevator outages?

The use of rotary lift equipment requires that the bearings, gears and bushings be lubricated with oil. This oil must be contained so that it does not leak out into the atmosphere. Elevator gearboxes are often installed by the manufacturer with conventional wiper seals and radial lip seals. Wiper and lip seals use the host equipment rotating shaft as the primary wiper sealing surface. Over time, the lift equipment’s default oil wiper seal design wears and scars the rotating shaft surface, creating a leak path. This is especially the case on worm drive gearboxes designed with axial shaft thrust under the wiper seal causing extra rubbing under the lip of the wiper seal, leading to deeper and wider fretting damage to the shaft. 

Isomag was able to provide a solution that not only eliminated the oil leaks, but no longer caused fretting to the expensive gearbox shafts.

Wiper seal failure and shaft wear of this magnitude can typically take place within 3,000 h of runtime. On elevator gearboxes, this can happen quickly, often within three to six months. Once a clearance is worn, lift equipment lubrication leakage is inevitable. This can lead to bearing failure due to lack of lubrication and a potential safety hazard for both the maintenance team and elevator passengers.

In 2018, Schindler saw the need for a long-term bearing seal for this application on a Westinghouse #38 unit in Texas. A returning oil leak was having to be fixed every few months, and a longer-term solution was sought. Isomag was able to provide a solution that not only eliminated the oil leaks, but no longer caused fretting to the expensive gearbox shafts. Isomag’s unique magnetic face technology allows a long-term sealing solution (>75,000 h) while not using the host equipment as a wearing surface. The customer has been very pleased with Isomag’s performance, and the gearboxes are still running leak-free today. 

Over time, the lift equipment’s default oil wiper seal design wears and scars the rotating shaft surface, creating a leak path.

Isomag seals are installed in equipment operating in the major industry sectors around the globe, but this Schindler project was Isomag’s introduction to the vertical-transportation industry. Isomag seals reduce the frequency of lift equipment oil leaks, which increases hassle-free operating life.