If you work with heavy machinery or industrial equipment, you've probably come across a 4 bolt flange bearing at some point. These bearings are commonly used in applications that require strong, stable support for rotating or linear motion. If you're considering purchasing them, here's what you should know before making a decision.

What Are 4 Bolt Flange Bearings?

A 4 bolt flange bearing is a type of bearing that’s mounted within a flanged housing and secured using four bolts. This design offers stability and makes installation easier, especially in tight spaces. The flange allows the bearing to be aligned properly with the shaft it supports, which is crucial for maintaining performance and longevity.

Materials Used in the Housing

• Cast Iron: Known for its durability, cast iron is often used in heavy-duty applications. It’s made from iron, silicon, and carbon, and its properties depend on the heating process during manufacturing.
• Pressed Steel: A cost-effective option, pressed steel is low-carbon steel that’s formed rather than machined, making it ideal for general use.
• Plastic or Thermoplastic: These materials are lightweight, resistant to corrosion, and often used where lubrication is not feasible. Examples include nylon and Teflon.
• Stainless Steel: Offers excellent resistance to chemicals and corrosion, making it suitable for harsh environments.

Materials Used in the Bearing Itself

• Aluminum: Lightweight and heat-conductive, aluminum bearings are often used in engines and high-speed applications.
• Steel: Strong and durable, steel bearings are common in industrial settings. High-carbon steel is often used for better load-bearing capabilities.
• Stainless Steel: Like the housing, stainless steel bearings resist corrosion and are used in demanding environments.
• Powdered-Metal Bearings: These are self-lubricating and porous, allowing them to absorb oil or other lubricants. They’re ideal for low-maintenance applications.
• Graphite-Metal Alloy Bearings: Self-lubricating and heat-resistant, these are great for high-temperature environments.
• Plastic Bearings: Strong and wear-resistant, they don’t require lubrication and can handle heavy loads in various conditions.

Common Applications

4 bolt flange bearings are typically used when the mounting area is perpendicular to the shaft. They come in 2, 3, and 4 bolt configurations, with the 4-bolt version being the strongest and best suited for heavy loads. When choosing a bearing, consider the shaft’s size and height, especially if space is limited.

Key Performance Considerations

• Speed: How fast the bearing can operate without failing.
• Bearing Life: Measured as L10, this indicates how long the bearing will last with 90% reliability.
• Load Capacity: Refers to the radial and thrust forces the bearing can withstand.
• Engineering Load: Includes all forces acting on the shaft, such as weight, belt tension, and unbalanced loads.
• Operating Temperature: Determines the performance of the bearing cage, seal, and grease under high temperatures.

Lubrication Needs

All ball bearings require some form of lubrication. Some are designed to be self-lubricating, using materials like bronze or oil-absorbent metals. Others need manual lubrication via a pump or grease fitting. Choosing the right type depends on your application’s maintenance requirements and environmental conditions.

For more information on different types of bearings, check out our article "What's the Difference Between Bearings?" on Machine Design.

Have questions about 4 bolt flange bearings or anything else? Feel free to reach out to us directly. We’re always happy to help!