Aluminum plain bearings

Aluminum plain bearings are lightweight, high-load capacity sliding bearings known for their excellent thermal conductivity and corrosion resistance. They are commonly used in engines and heavy machinery due to their high fatigue strength and compatibility with steel shafts.
Key Features and Benefits
Lightweight: Aluminum is significantly lighter than other bearing materials like bronze or steel, contributing to the overall weight saving of machinery.
High Load and Speed Capability: Monometallic (solid) or steel-backed aluminum bearings can handle heavy loads and operate at very high surface speeds.
Excellent Thermal Conductivity: Aluminum's good thermal conductivity allows for efficient heat dissipation from the bearing surface, which is crucial for high-speed applications like engine bearings.
Corrosion Resistance: They offer high resistance to corrosive agents commonly found in lubricants and many industrial environments.
Compatibility with Steel Shafts: Aluminum alloys are mechanically compatible with steel, and in many cases, can run against unhardened steel shafts, potentially reducing shaft manufacturing costs.
Conformability and Embeddability: Aluminum bearing materials generally possess superior conformability and embeddability (the ability to absorb small dirt particles without damaging the shaft) compared to harder materials.
Cost-Effective: Their simple manufacturing process and use of abundant aluminum as a base material result in lower initial and maintenance costs compared to more complex bearing types.
Types and Materials
Aluminum is typically used as the strong backing material, with a specialized sliding layer applied to the inner surface to reduce friction.
Solid Aluminum (Monometallic) Bearings:
Description: These are fully aluminum, often cast or wrought from specific alloys (e.g., B750-T5 or A750) to achieve desired strength and bearing properties.
Use: Ideal for applications requiring high load-carrying ability and resistance to significant shock loads, such as aircraft landing gear assemblies and power shovels.
Steel-Backed Aluminum (Bi-metal) Bearings:
Description: A common configuration where an aluminum alloy layer (e.g., Al-Sn, Al-Sn-Si-Cu) is welded onto a steel strip for superior mechanical strength and improved heat conductivity.
Use: Widely used in internal combustion engines as connecting rod and main bearings.
Aluminum-Polymer Composite Bearings:
Description: These linear plain bearings use an anodized aluminum shell combined with a self-lubricating liner (such as Frelon or PTFE blends) for maintenance-free operation and the ability to handle high loads in linear or oscillating motion.
Use: Ideal for corrosive environments or applications requiring self-lubricating, maintenance-free performance.
Applications
Due to their unique combination of properties, aluminum plain bearings are utilized across various demanding industries:
Automotive Industry: Commonly found as connecting rod and main bearings in internal combustion engines and transmissions.
Heavy Machinery: Essential in equipment such as presses, lathes, boring mills, power shovels, and track rollers to withstand high shock loads.
Aerospace: Employed in aircraft landing gear assemblies for their high strength-to-weight ratio and durability.
Industrial Equipment: Found in pumps, compressors, and hydraulic systems.