Linear bearings form the basis of controlled movement in machines and production lines. You will find them in mechanical engineering, automation and manufacturing, where precision, load capacity and reliability come together. However, making the right choice requires more than just comparing catalogues. Loads, environmental conditions and desired service life determine which type of bearing is suitable for your application. LM Systems guides you through this process with customer-specific solutions that meet your technical requirements.
What are linear bearings?
Linear bearings enable controlled linear motion with low frictional resistance. They are used in assembly machines, packaging lines, machining centres and measuring setups, among other things. Depending on the design, they absorb forces and mass while maintaining accurate repeatability of movement. Within the LM Systems range, linear bearings are always tailored to the application, so there is no standard selection, but rather engineering based on load and operating conditions.
Difference between recirculating ball bearings and plain bearings
An important distinction within linear bearings is between recirculating ball bearings and plain bearings. Recirculating ball guides are suitable for applications with higher mass and moment loads. In addition, a service life calculation is possible for these systems based on load and stroke length. Plain bearings have a simpler design and function well at lower loads, but they cannot absorb moment loads. This makes them less suitable for dynamic machine construction applications where stability and accuracy are required.
Types of linear bearings and operating principles
There are various operating principles within linear bearings. The most commonly used variants are ball bearings and roller bearings. Ball bearings offer low friction and high speed, while roller bearings can handle higher loads due to their larger contact surface. Brands such as THK supply both types, with LM Systems adapting the configuration to your machine function and desired service life.
Precision and clearance adjustment
The accuracy of linear bearings is determined by the selected tolerance class. Guides are supplied in the Normal class as standard. If your application requires higher positioning accuracy, H, P, SP or even UP classes are also available. In addition, the clearance adjustment plays a role. Carriages can be designed to be backlash-free or provided with a slight preload C1 or moderate preload C0. A higher preload results in a stiffer and more stable system, which is particularly relevant for varying loads and short cycle times.
Linear bearings are mainly used in industrial environments within mechanical engineering and manufacturing. In dirty conditions, additional seals can be used to extend the service life. These include extra scrapers and sealing lips. In extremely dirty conditions, LM Systems deliberately chooses not to use ball bearings but roller guides from Nadella Rollon, which are more resistant to dirt and coarse particles.
Use of materials
The performance of linear bearings is closely related to the materials used. Runners and carriages are manufactured from high-quality steels with a specific carbon alloy. This composition makes it possible to harden and regrind the ball and roller tracks. This creates a controlled surface roughness and dimensional accuracy, which contributes to predictable running behaviour and constant precision over the service life.
Lubrication of linear bearings
The lubrication required for linear bearings depends on the type of bearing and the environmental conditions. Carriages without ball chain technology generally require lubrication every 100 kilometres. Models with ball chain technology require lubrication every 5,000 kilometres or twice a year. By adhering to these intervals, you can prevent increased wear and maintain a stable friction level.
Speed, friction and dynamics
Depending on the type of linear bearing, speeds of 3 to 5 metres per second are achievable. Specific models even allow speeds of up to 7 metres per second. Accelerations can reach up to 50 metres per second squared. The final performance always depends on load, lubrication and installation quality. That is why LM Systems assesses these factors jointly during the engineering process.
Correct assembly is therefore crucial to the performance of linear bearings. Tables are available for each type of guide and size, specifying the flatness and parallelism requirements for the mounting bed. These tolerances are linked to the selected preload class. Taking this into account in the design prevents additional stresses in the system and extends the service life of the guide.
That is why LM Systems does not supply standard solutions, but tailored systems that fit within your machine concept. From selection to installation advice, we support you with practical engineering knowledge. Would you like to know which configuration best suits your machine? Feel free to contact us for technical advice.