SKF NUTR25 A Stützrollen (25x52x25)

As a track or cam roller, this component runs directly on a mating track or cam surface. The dynamic load rating of 44.6 kN characterises this bearing. The static load rating is 61 kN. The open form has the lowest frictional torque in this range, but requires the construction to keep the rolling set clean. This version of the support roller brings no sealing element with it; the rolling chamber is exposed on both sides.

At the right mounting locations that is not a shortcoming but the precondition for the machine's lubrication to reach the rolling set: in oil-lubricated housings, under oil mist, or at bearing positions with a relubrication bore in the pin through which grease is fed directly into the rolling chamber. At the same time the frictional torque comes out lowest, and with this design that is more than a side quantity — a support roller is not driven but carried along by the contact with its track, and the more easily it starts to turn, the more reliably it rolls instead of sliding on the track.

The reverse side is equally distinct: debris from the running track, dust and moisture reach the rolling chamber unhindered, and initial filling as well as relubrication rest entirely with the surrounding construction; in dry or contaminated surroundings without a lubricant supply, a sealed or shielded version is preferable. In other respects the design remains that of the support roller: the thick-walled outer ring, hardened through the running depth, takes the contact pressure from the contact with the mating track, whose hardness and flatness have a share in determining the load capacity of the pairing; the profile of the running surface determines the tolerance to an angular error; the roller is set onto a journal through its bore and supported on both sides. Rings and rolling elements are made of standard bearing steel.