What are the two common types of PTFE structural bearings? Key Differences & Applications

PTFE structural bearings are widely used in engineering applications due to their low friction, chemical resistance, and ability to handle high loads. The two most common types are PTFE sliding bearings and POT-PTFE bearings, each designed for specific structural and load-bearing requirements. These bearings leverage PTFE's unique properties, such as self-lubrication and thermal stability, to ensure smooth movement and durability in demanding environments.

Key Points Explained:

1. PTFE Sliding Bearings

   • Design & Function: These bearings consist of a PTFE sliding surface bonded to a metal backing plate. They allow linear or rotational movement with minimal friction, making them ideal for bridges, buildings, and heavy machinery.
   • Advantages:
     • Exceptionally low coefficient of friction, reducing wear and energy loss.
     • High chemical resistance, suitable for harsh environments.
     • Can operate across a wide temperature range (-200°C to +260°C).
   • Applications: Commonly used in expansion joints, seismic isolators, and sliding surfaces where movement must occur without sticking or binding.

2. POT-PTFE Bearings

   • Design & Function: POT-PTFE bearings combine an elastomeric pad (often rubber) with a PTFE sliding surface, housed in a steel pot. This design accommodates multi-directional movement and rotation while distributing loads evenly.
   • Advantages:
     • Excellent load-bearing capacity due to the elastomeric layer's ability to deform under pressure.
     • Dampens vibrations and absorbs shocks, enhancing structural stability.
     • The PTFE surface ensures smooth sliding even under high compressive loads.
   • Applications: Frequently used in bridge bearings, heavy industrial equipment, and structures requiring both load distribution and movement flexibility.

3. Material Enhancements for PTFE Bearings

   • Filled PTFE: To improve mechanical properties like compressive strength and wear resistance, PTFE is often blended with fillers such as glass fibers, bronze, or carbon. For example:
     • Glass-filled PTFE: Increases durability but may be more abrasive.
     • Bronze-filled PTFE: Enhances dimensional stability and reduces creep.
     • Carbon-filled PTFE: Boosts thermal conductivity and wear resistance.
   • These custom PTFE parts are tailored to meet specific performance criteria, ensuring longevity and reliability in specialized applications.

4. Selection Considerations

   • Load Requirements: POT-PTFE bearings are better for heavy, dynamic loads, while sliding bearings suit lighter, continuous motion.
   • Environmental Factors: Chemical exposure or extreme temperatures may dictate the choice of filler materials.
   • Movement Type: Rotational vs. linear movement influences whether a POT or sliding design is preferable.

By understanding these key distinctions, engineers and purchasers can select the optimal PTFE bearing type for their project, balancing performance, cost, and longevity. Have you considered how the specific load and movement requirements of your application might influence this choice?

Summary Table:

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