In bearings that operate at high speeds, the force created by the rolling elements’ moving mass causes a significant additional internal load. Especially in cylindrical roller bearings with relatively heavy solid brass cages, the acceleration of the rolling elements requires a large amount of energy.
A further issue directly associated with the mass inertia of rollers and cage is the sliding friction that frequently occurs in rolling bearings that are insufficiently loaded or accelerated too quickly and which, in extreme cases, can destroy the bearing’s precision-finished raceway surfaces.
Less is more
With the aim of reducing moving mass, engineers of NKE’s design department have comprehensively revised the existing standard solid brass cage design as part of a design review process.
“We wanted to substantially reduce cage mass without compromising the proven technical characteristics of our solid brass cages”, explains Johann Bergmayr, team leader in NKE’s Technical Service department.
“By fully utilising the available weight-savings potential, we were able to cut cage mass by nearly a fifth compared to the previous design without affecting its roller guidance accuracy”, emphasises Faruk Duskunovic, leader of the NKE design team and responsible for the technical implementation of the idea. “At the same time an optimisation of the cage bar cross-sections has resulted in an improved lubricant distribution in the bearing.”
In line with NKE’s philosophy of ongoing product development, the improved cage design will be gradually phased in for all of NKE’s standard bearings with solid brass cages.
NKE produces standard and special bearings for all industrial applications. In addition to product development and application engineering NKE provides a full range of technical services and training. NKE’s products are distributed through 15 international representative offices and more than 240 distribution outlets in 60 countries.