Linear plain bearings – find manufacturers and suppliers

Linear plain bearings are a special type of bearing used in linear technology to enable linear (straight-line) movement with minimal frictional resistance.

In contrast to rolling bearings, which work with balls or rollers, linear plain bearings are made of materials that ensure a low-friction and precise motion sequence through sliding friction.

Below you will find an overview of the design and function of linear plain bearings, as well as an overview of the areas of application and their advantages:

Structure of linear plain bearings:

Linear plain bearings typically consist of three main components:

1. Bearing bush: 
   This encases the sliding material and serves as the housing of the bearing. 
   It is often made of metal or plastic and provides a stable structure to hold the bearing in place on the guide rail or shaft.
2. Sliding material:
   This is the actual material that enables linear movement.
   Commonly used sliding materials are:
   1. Plastics (e.g. PTFE, POM): these are self-lubricating, offer low friction and are particularly resistant to abrasion.
   2. Bronze or sintered metal: These materials are often impregnated with lubricants to support low-friction movement.
   3. Sliding coatings: Special coatings such as PTFE or graphite are often used to reduce friction and extend service life.
3. Mounting mechanisms:
   In many applications, linear plain bearings are equipped with a housing or special clamps that allow the bearing to be easily attached to its guide rail.

The exact design depends heavily on the application. For example, there are open bearings (for higher loads) and closed designs (for greater stability with lower loads).

How linear plain bearings work:

Linear plain bearings function through a sliding motion between the bearing and a guide rail or shaft, without the involvement of rolling elements such as balls or rollers.

Here is a detailed description of how they work:

1. Sliding friction:
   The sliding material moves directly over the guide rail or shaft, creating sliding friction. 
   The movement is uniform and the frictional force remains constant as long as no lubricant is required.
2. Self-lubrication:
   In many linear plain bearings, the sliding surfaces are made of self-lubricating materials such as PTFE or special plastics. 
   These materials release microscopic amounts of lubricant when under load, reducing friction. 
   This often eliminates the need for additional lubrication and ensures that the bearing requires little maintenance.
3. Wear reduction:
   The bearing bush and the sliding material are designed in such a way that the sliding material does not wear out or at least only experiences minimal wear. 
   This is often achieved by using special materials or coatings that withstand high loads and wear.
4. Load distribution:
   Linear plain bearings distribute the load evenly over the sliding surface. 
   This distinguishes them from rolling bearings, where the load is concentrated on small points (balls or rollers). 
   The even load distribution enables a more stable movement and increases the service life of the bearing.

Use and application areas of linear plain bearings:

Due to their specific properties, linear plain bearings are particularly suitable for applications where robust and low-maintenance solutions are required.

1. Automation technology:
In conveyor systems and robotic systems that have to perform linear movements, plain bearings are popular due to their ease of maintenance and long service life.

2. Medical technology:
Medical devices that need to perform precise movements often use plain bearings because they are very quiet and often self-lubricating, which supports a sterile and clean environment.

3. Printing and packaging machines:
These machines often perform repetitive, linear movements and benefit from the shock resistance and low vibration properties of plain bearings.

4. Agricultural and construction machinery:
Plain bearings are often used in environments that are dusty or dirty. Here they are very resistant to contamination and have a long service life.

5. Vehicle construction:
In vehicles, especially commercial or off-road vehicles, plain bearings are used for the linear movement of components that are exposed to high loads and shocks.

Advantages of linear plain bearings:

• As many plain bearings are self-lubricating, they require no additional lubrication and are particularly easy to maintain.
• They are usually less expensive than roller bearings, which is economically advantageous for large quantities.
• Plain bearings are robust and function reliably even in dirty and dusty environments.
• The sliding movement results in less noise, which makes them suitable for applications in noise-sensitive areas such as medical technology or household appliances.

Linear plain bearings are indispensable components for linear movements, especially in applications that require high load capacity and freedom from maintenance. Thanks to the selection of suitable materials and the possibility of dispensing with lubricants, they are cost-effective, robust and low-maintenance and are used in many branches of industry.

Below is an overview of the most important points that should be considered when purchasing linear plain bearings:

When purchasing linear plain bearings, it is important to consider various factors to ensure the best possible performance and service life in the intended application.

• Consider how much weight the linear plain bearing needs to support. The load capacity should be selected so that the bearing is not overloaded during continuous operation.
• Depending on the application, a load capacity in several directions may be required. Therefore, check whether the bearing can support axial or radial loads.
• Check whether the selected linear plain bearing requires additional lubrication. In harsh environments and where there is a high level of friction, regular lubrication may be beneficial.
• Linear plain bearings made of self-lubricating plastics (such as PTFE or special polymers) are particularly suitable for applications where regular maintenance is not possible.
• The coefficient of friction should be as low as possible in order to optimize efficiency and energy requirements. A low coefficient of friction ensures less wear and a longer service life.
• Depending on the application, the running accuracy should be checked. Precise applications, such as in medical technology or in measuring devices, require very high running accuracy.
• Check whether the bearing is suitable for the temperatures that occur in your area of application. Some plastics or coatings lose their mechanical properties at high temperatures.
• In environments with dirt, dust or moisture, closed bearings and self-lubricating materials are recommended. In such environments, avoid linear plain bearings that require lubrication.
• Linear plain bearings are designed for moderate speeds and are less suitable for extremely fast movements. Therefore, pay attention to the maximum permissible speed.
• For applications with a high number of cycles and continuous movement, sliding materials should be selected that last a long time even under frequent stress.
• Pay attention to the dimensions of the linear plain bearing and whether it matches the guide rails or shafts that are already installed in your application.
• Some bearings are easier to fit than others. check whether the bearing and its housing are designed for easy mounting.
• Consider how long you want the bearing to last in your system and what the service life requirements are. Choose a bearing with a service life that meets the requirements.
• If regular maintenance is not possible, choose maintenance-free or self-lubricating bearings that do not require additional lubrication.
• Cheaper bearings are often an economical choice in the short term, but may have a shorter service life or require more maintenance. Consider the total cost over the life cycle.
• Pay attention to delivery times, especially if you need to reorder bearings at regular intervals.
• Ensure that the bearing meets the desired quality standards (e.g. ISO certifications). This is particularly important in safety-critical or regulated industries, such as medical technology or aviation.

When purchasing linear plain bearings, in addition to the basic requirements for load capacity and material, you should also pay attention to factors such as operating environment, service life and costs. Ease of installation and quality certifications can also be important decision criteria, depending on the area of application. Careful selection ensures optimum performance and reduces maintenance costs in the long term.

Linear plain bearings can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Linear plain bearings from all over the world can be found on Exportpages.