NKE PWKR47-2RS Kurvenrollen (20x47x66)

As a track or cam roller, this component runs directly on a mating track or cam surface. This NKE bearing measures 20x47x66 mm and weighs 0.38 kg; the specification table carries the supplementary technical details. The integrally formed threaded stud is screwed in, the roller cantilevers out on one side, and the hardened outer ring runs on the track.

This stud-type track roller is closed at both end faces with a contact seal. It thereby offers the most extensive protection in this range: the lip bears against its counterface, retains the lubricant in the rolling chamber and excludes debris, dust and moisture. At a cam or guide track that is a tangible advantage, since the contact between running surface and track inevitably generates particles, and hard particles leave indentations in the rolling contact which continue to act as local peaks in pressure.

The counterpart has to be weighed deliberately with this design. A stud-type track roller is not driven but set turning by the contact with its track; the frictional torque of the bearing lip therefore increases the tendency to slide instead of rolling under unfavourable conditions, and it lowers the permissible speed. Where the track reliably drives the roller and the environment is contaminated, the protection prevails; where the roller only lightly touches the track or runs very fast, a version with lower friction should be examined.

In addition, the seal material limits the operating temperature and the media resistance. The fastening remains characteristic: the integrally formed threaded stud is screwed into a plate, lever or cheek, the roller cantilevers out on one side, and the bending moment arising from the track force is carried off through the seating face and the bolted joint; the squareness of the mounting hole determines whether the roller runs square to the track.

The thick-walled outer ring, hardened through the running depth, takes the contact pressure from the track contact. Rings and rolling elements are made of standard bearing steel.