Timken’s tapered and spherical roller bearings for tunnel boring cutter heads and more

Coal miners work far below the earth’s surface and have little time and less space to deal with unscheduled breakdowns. With enormous rotational forces and constant impact loads on the cutter heads, equipment productivity is paramount, especially when downtime costs between $10,000 and $15,000 per hour for room and pillar mining.

Timken offers a range of tapered and spherical roller bearings used in cutter heads, propulsion track systems and conveying systems. Timken spherical roller bearings and Timken tapered roller bearings help manage radial and combined loads because they can be customized to meet specific application requirements. Timken precision roller chain in the propulsion system helps keep continuous miners moving.

Enhanced Surface Finishes Help Increase Bearing Life and Reliability
In continuous mining equipment, bearing loads are unpredictable due to a variety of different operating conditions. These conditions lead to uneven loading and large overturning moments for the cutter drum bearings.

When Joy Global needed help to improve the performance of their cutter drums, they called Timken. The bearing damage was fine grain spalling from heavy loads and low-speed conditions that did not allow the lubrication to generate sufficient film strength to separate the rolling element surfaces. The solution leveraged tribology technologies that improved surface finishes by reducing the surface roughness. Timken manufactures bearings with enhanced surface nishes that mitigate the effects of fine grain spalling. The improved surface finish is designed to allow for better separation of the steel rolling surfaces, preventing the asperity contact that leads to premature bearing damage.

As a result, Joy experienced increased bearing life and reliability of their machines to meet life requirements between rebuild cycles. According to Mark Ziegler, Joy Global Principal Engineer,

“We enjoy working with Timken on these projects. Their engineering team assists with inspection of eld parts and then validates product improvements through their analysis tools. With global engineering support, we rely on Timken to support us whether we are in the United States, China or anywhere in between.”

Timken
www.timken.com