Ball bearings combined with hardened steel shafts are one of the industry's most proven solutions for linear motion – and the technology is just as relevant today as when it was introduced. The low friction, smooth operation and high precision make the system both cost-effective and easy to integrate into a variety of machines. In this article, we will go over why ball bearings are so popular, what applications they are suitable for, and when other options may be a better choice.
Why are ball bearings and hardened steel shafts so popular?
Ball bearings in combination with hardened steel shafts are one of the most established solutions for linear motion in industrial designs. A ball bearing consists of circulating balls that roll along a hardened and ground shaft. The rolling contact minimizes friction and wear, providing stable, smooth and energy-efficient movement. The technology is easy to integrate, forgiving during assembly and very cost-effective. At the same time, it offers high precision, low friction and long service life.
It is precisely the combination of simplicity and performance that makes this technology so popular in many automation solutions. Unlike many other linear bearing solutions, a hardened shaft can be customized through various types of post-processing and often function as a structural, load-bearing element in your machine.
The development of materials in recent decades, such as plastic cages, seals and lightweight materials, has made the range of applications for ball bearings even wider.
Advantages of ball bearing solutions:
- Low friction and smooth, vibration-free running
- High precision and repeatability
- Long service life and high operational reliability
- Easy installation and standardized components
- Available in many variants for different applications
Typical uses
There are several variations of ball bearings, which makes the technology flexible to adapt to requirements and environment. Closed bushings are suitable when the shafts are mounted unsupported, while open bushings are used in combination with supported shafts, typically for long strokes. Compact bushings are suitable for tight designs and stainless steel variants are ideal in demanding environments where hygiene or corrosion resistance is important.
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Five common applications |
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Customer case: Packaging machine with high cycle rates and hygiene requirements
A Swedish food packaging company developed a new filling station where fast and repeatable vertical movement was crucial for production flow. The machine would run at high cycle rates, be easy to clean and have a low noise level to improve the working environment.
The solution was to integrate sealed stainless steel ball bearings together with stainless steel hardened shafts. The low friction provided a smooth and stable movement, while the choice of materials made the construction hygienic and easy to keep clean. After the test period, the customer was able to see that service intervals increased by approximately 25 percent, that noise levels decreased and that the filling process became significantly more stable even at high speed.
This is a clear example of how the classic ball bearing, used correctly, can contribute to both a better working environment and higher productivity.
When should you not use ball bearings?
There are situations where other linear guides, such as rail guides or roller guides, may be preferable:
- When you need extreme rigidity and zero backlash.
Ball bearings have a relatively elastic contact with the shaft and actually work best with a few 1/100 mm of clearance. - In environments with a lot of dust, dirt or particles.
Both ball bushings and rail guides use rather small balls that re-circulate. Contamination can block this function. - Where extremely high precision is required while simultaneously handling large loads.
In such cases, ball bushings are limited by their relatively low rigidity, and unsupported steel shafts will deflect under load. Even when used with support, they cannot be aligned as precisely as a linear rail guide
