SKF KR30 PPX Kurvenrollen (12x30x40)

As a track or cam roller, this component runs directly on a mating track or cam surface. This SKF bearing measures 12x30x40 mm and weighs 0.087 kg; the specification table carries the supplementary technical details. At each end face sits a plastic washer that both guides axially and seals by means of an integrally formed lip. The stud-type track roller is a track roller with an integrally formed threaded stud: it is not slipped onto a pin but screwed by its own stud into a plate, a lever or a cheek, and cantilevers freely from there.

This method of fastening shapes its layout. Because the force from the contact with the track acts at the free end, a bending moment arises in the stud which is carried off through the seating face and the bolted joint; the seating area, the tightening torque and the squareness of the mounting hole therefore belong to the layout and not to assembly routine — a hole drilled at an angle sets the roller askew to the track and forces the contact pressure out to the edge of the running surface.

Versions with an eccentric stud make use of exactly this relationship and allow the roller to be set against the track after mounting by turning it. The plastic axial sliding washer at both end faces takes on two tasks at once: it guides the roller axially against the support and closes the rolling chamber with an integrally formed lip. The sliding pair of plastic against steel offers little resistance to rotation, which benefits a roller that is not driven; the polymer material, however, limits the operating temperature and the media resistance more tightly than the hardened steel of the rolling set, which is to be checked before use.

The outer ring is thick-walled and hardened through the running depth, since it takes the contact pressure from the contact with the track; the hardness and course of that track have a share in determining the load capacity of the pairing. Rings and rolling elements are made of standard bearing steel.