Pillow Blocks Vs. Standard Bearings: Which Is Better for Your Equipment?

When it comes to selecting the right type of bearing for your equipment, the choice can often be overwhelming due to the variety of options available. Among the many choices, pillow blocks and standard bearings are two of the most commonly used bearing solutions across various industries. Understanding the differences between these two types of bearings is crucial for ensuring optimal performance, longevity, and cost-effectiveness for your equipment.

In this article, we will explore the advantages and disadvantages of pillow blocks and standard bearings, providing insights into their unique features, applications, and performance benefits. By the end of this article, you'll have a clear understanding of which type of bearing is the best fit for your machinery and industrial needs.

What Are Pillow Blocks?

A pillow block is a type of mounted bearing unit designed to support rotating shafts. Typically consisting of two main components—the bearing insert and the housing—pillow blocks are widely used in applications that require a reliable and durable solution for supporting rotating components. The bearing insert is generally a spherical roller bearing, known for its ability to handle both radial and axial loads, while the housing, often made of cast iron or steel, provides protection and support for the bearing insert.

Pillow blocks are often referred to as housed bearings, as they are pre-assembled and housed in a casing that provides additional support. These units are designed to fit onto a machine's frame, ensuring that the bearing remains securely in place and properly aligned with the shaft.

What Are Standard Bearings?

Standard bearings, also known as plain bearings or unmounted bearings, are typically individual bearings that are not housed or pre-assembled. They are designed to be mounted directly onto a shaft or housing and are used in a variety of applications, such as automotive, industrial, and machinery sectors. Standard bearings come in different types, including ball bearings, roller bearings, and sleeve bearings.

Unlike pillow blocks, which include the housing and bearing insert together, standard bearings are sold as individual components. They are often used in situations where the machinery design allows for direct mounting of the bearing without the need for additional support from a casing or housing.

Key Differences Between Pillow Blocks and Standard Bearings

To determine which type of bearing is better for your equipment, it is essential to understand the key differences between pillow blocks and standard bearings. Below are the critical factors to consider:

Design and Structure

Pillow blocks are complete units consisting of both the bearing insert and a protective housing. This design allows for easy installation, better alignment, and protection from contaminants, which makes them ideal for demanding applications such as conveyors, mixers, crushers, and other heavy-duty equipment. The housing also helps absorb vibrations and provides additional support to prevent premature wear.

On the other hand, standard bearings are typically sold as individual components that require separate mounting. While they are more compact and often used in lighter-duty applications, they may require additional support or housing to ensure proper alignment and reduce wear, especially in high-vibration environments. Standard bearings are more versatile when used in applications that do not require additional protection or support.

Load Capacity

One of the most important considerations when choosing a bearing is the load capacity. Pillow blocks are designed to support both radial and axial loads, making them ideal for heavy-duty applications. The spherical roller bearings used in pillow blocks are built to handle large radial loads, making them suitable for high-load applications such as material handling systems, construction machinery, and mining equipment.

Standard bearings, such as ball bearings, are typically better suited for lighter loads. While they can handle radial loads effectively, they may not be as capable of handling high axial loads or heavy-duty conditions. However, there are variations of standard bearings, such as tapered roller bearings, that are capable of handling higher axial loads but still may not perform as well as pillow blocks in heavy-duty environments.

Vibration Resistance

In industries like mining, manufacturing, and agriculture, equipment often operates under harsh conditions with constant vibrations. Vibration resistance is a critical factor in ensuring the longevity and reliability of bearings.

Pillow blocks excel in this regard because the housing absorbs the vibrations, reducing the stress on the bearing insert. The spherical roller bearings used in pillow blocks are also designed to absorb and resist vibrations, ensuring that the bearing remains aligned and functional even in high-vibration applications. This feature is particularly beneficial in equipment like crushers, grinders, and conveyor systems, which experience continuous movement and impact.

Standard bearings, especially ball bearings, are more susceptible to vibration-induced wear. Without additional housing or support, they may experience misalignment or damage when exposed to continuous vibrations. While some standard bearings are designed to withstand vibration, they typically don't perform as well as pillow blocks in such environments.

Sealing and Protection

Pillow blocks often come with advanced sealing options, such as NBR double-lip seals, trip-lip seals, and Teflon seals. These seals protect the bearing insert from contaminants such as dirt, dust, moisture, and chemicals, which can lead to premature bearing failure. The housing also offers additional protection, keeping the bearing insert safe from external elements.

Standard bearings may come with seals as well, but they often require additional protective measures to ensure their longevity. In some cases, external housings or covers are needed to protect the bearing from contaminants and harsh environmental conditions. While standard bearings are generally more compact, their protection against contaminants is often less robust compared to pillow blocks.

Maintenance and Lubrication

Pillow blocks are designed for easy maintenance, with the ability to replace the bearing insert without disassembling the entire unit. This can significantly reduce downtime and maintenance costs. Additionally, many pillow blocks come with lubrication ports for easy grease application, ensuring that the bearing operates smoothly and remains well-lubricated.

In contrast, standard bearings often require more frequent inspections and maintenance. The process of replacing a bearing insert or lubricating the bearing may be more complicated and time-consuming, especially when the bearing is mounted directly on a shaft without additional housing. However, standard bearings are often easier to access for maintenance in smaller, more compact applications.

When to Choose Pillow Blocks Over Standard Bearings

While both pillow blocks and standard bearings have their advantages, the choice between the two largely depends on the specific requirements of your application. Here are some scenarios where pillow blocks are the better option:

• Heavy-duty applications: If your equipment is exposed to high loads, continuous vibration, and harsh environmental conditions, pillow blocks are the ideal choice due to their high load capacity, vibration resistance, and superior sealing.

• High-maintenance environments: If minimizing downtime and simplifying maintenance are priorities, pillow blocks offer easy maintenance and lubrication access, making them a more efficient choice.

• Harsh operating conditions: If your machinery is exposed to contaminants such as dust, moisture, or chemicals, pillow blocks' superior sealing and protection features make them the better option.

When to Choose Standard Bearings

Standard bearings may be a better choice for applications where:

The machinery operates under lighter loads and doesn't require the high load capacity of pillow blocks.

Compact design is a priority, and additional housing or protection is not necessary.

The operating environment is not as harsh, and vibration resistance is not a significant concern.

Conclusion

Both pillow blocks and standard bearings have their place in the world of industrial machinery. However, for heavy-duty applications that involve high loads, continuous vibrations, and harsh environments, pillow blocks are the superior choice due to their enhanced durability, vibration resistance, and sealing capabilities. By providing better protection, easier maintenance, and increased lifespan, pillow blocks offer significant advantages in the long run, making them a valuable investment for your equipment.

For lighter-duty applications, standard bearings may be sufficient and more cost-effective. However, when considering the overall performance, durability, and cost-effectiveness for heavy-duty machinery, pillow blocks often prove to be the better option.

For more information on pillow blocks and their applications, visit WGB Bearing, where we offer high-quality bearing solutions tailored to meet the specific needs of your machinery.