Rolling elements: Load capacity and service life

Rolling elements are essential components in modern mechanical engineering and linear technology. Their load capacity, precision, and durability make them indispensable in various industrial applications. This text highlights their areas of use, technological advantages, and the calculation of their service life, considering specific influencing factors.

Applications of Rolling Elements

Rolling elements are employed across various industries, including:

• Mechanical Engineering: In grinding machines and machining centers, rolling elements ensure precise guidance even under heavy loads.
• Medical Technology and Biotechnology: They are used in devices such as computed tomography scanners or microtomes, where utmost precision and smooth operation are critical.
• Electronics and Semiconductor Industry: Applications like wire bonding or microchip manufacturing rely on the high reliability of rolling elements.
• Aerospace: Rolling elements are used in extreme environments, such as vacuum conditions or high-temperature applications.

Advantages of Rolling Elements

Rolling elements offer a wide range of benefits:

• High Load Capacity: They distribute loads evenly, achieving high load ratings.
• Precision and Smooth Operation: Optimized designs minimize friction, ensuring uniform motion.
• Flexibility and Customization: Thanks to various materials and coatings, such as corrosion-resistant steel or DURALLOY®, rolling elements can meet specific requirements.
• Reduced Maintenance: Innovative technologies like DryRunner® coatings enable lubricant-free operation, reducing maintenance needs.

Calculating Service Life

The service life of a rolling element is primarily determined by its load capacity and the applied load. As discussed in previous sections, these factors are key to lifetime calculation. An accurate assessment of the forces acting on the rolling elements is particularly important.

Challenges in Load Distribution

A significant challenge lies in considering the behavior of the surrounding structure during force transmission. Elastic deformations in a machine bed or geometric errors can lead to only a small portion of the installed rolling elements being effectively loaded. To address this issue, the following approaches can be utilized:

1. Measurements on Functional Models: These provide empirical data for specific applications.
2. Finite Element Method (FEM) Calculations: These allow detailed simulation of force distribution.

However, as these methods are time- and cost-intensive, simplified models are often used in practice. In such cases, the external load is distributed across a few rolling elements using the correction factor RTmin, enabling dimensioning.

Load Ratings and Standards

The load ratings CC/roller provided in the catalog are based on empirical data and do not correspond to values calculated according to DIN standards. However, they offer a practical foundation for dimensioning.

Conclusion

Rolling elements are indispensable for a wide range of technical applications. Their efficiency depends on the precise determination of load capacity and service life. Advanced simulation methods and empirical data enable the optimal adaptation of these components to modern industrial requirements. With innovative materials and optimized designs, rolling elements significantly contribute to improving precision, reliability, and cost-effectiveness.