Needle roller bearings

The different types of bearings (ball, needle and roller) are generally complementary rather than competitive.

Needle roller bearings are characterized by the use of small-diameter, long-length rolling elements. Their small size and high load capacity (figure 1 ) have led to a considerable increase in their use in recent years.

Radial, axial or combined, they can be found in all fields: automotive (figure 2 ), aerospace, robotics and machine tools, and whenever high performance in a limited space is required by the application.

A constant concern to improve product quality and reliability has led manufacturers to make considerable progress in both the design and manufacture of needle roller bearings. In particular, numerous advances have been made in the manufacture of rolling elements, whose geometric rigor in terms of shape and dimensions has resulted in guideways of unrivalled precision. Analysis of operating conditions using increasingly sophisticated mathematical models has enabled us to optimize bearing design and even adapt it to specific applications. This has led, for example, to the virtual disappearance of full needle roller rings in favor of needle roller and cage assemblies, which offer greater assembly flexibility while providing much better guidance of rolling elements in all operating conditions.

In addition to their advantageous load/space ratio, needle roller bearings are characterized by their low cost.

Whether they're machined from solid or made from pressed sheet metal components, they can meet every need, from one-offs to small, medium and very large production runs.

They allow the use of materials adapted to the application, such as traditional bearing steels for core treatment, stainless or high-temperature steels, and low-carbon strip for surface treatment.

They can incorporate various additional functions, such as sealing or raceways. For example, needle roller thrust bearings are often combined with treated plates. Whether additional or integrated into the assembly, they avoid the need for precise machining and treatment of the raceways by the user.

Table 1 compares the main characteristics of the different types of needle roller bearing.