At the most basic level, industrial bearings are designed to facilitate smooth rotational motion while reliably accommodating static and dynamic loads. Though the equipment applications may be incredibly complex, this basic functionality is at the core of how virtually all industrial bearings operate.

Below, we take a look at static loads vs. dynamic loads, how these different types of loads affect bearing components, and how we account for these factors in manufacturing quality high-performance bearings for the specific application at hand.

The Basics of Static vs. Dynamic Loads for Industrial Bearings:

Static Loads Explained

Static load generally refers to a load exerted on a bearing when it’s stationary or at rest. However, static loads can also include operational conditions where a bearing undergoes very slow movement which is not sufficient to dynamically disperse the loads via rolling action. In other words, the bearing is rotating so slowly that sudden loads are still “felt” statically, not rotationally.

A crucial specification to keep in mind is the static load capacity of the bearing. That refers to the maximum load or weight the bearing will reliably hold before permanent deformation (such as brinelling) or damage is likely to occur.

Of course, the maximum capacity is especially crucial for bearing applications in which shock loads or heavy weighting are expected to occur while the bearing is not in motion – e.g. industrial conveyors and other factory material handling systems, or pretty much any machine that utilizes an emergency stop feature.

Dynamic Loads Explained

Dynamic load refers to a load exerted on a bearing as it undergoes continuous movement – i.e. generally whenever the attached equipment is operational. Essentially, a bearing’s dynamic load capacity is its functional life within the expected use case.

Radial and axial loads are both crucial considerations from a dynamic perspective, as these different types of loads will cause different types of stress and wear to the bearing. Carefully determining reliable operation under these conditions gives us a bearing’s “L10 Life” – a measurement derived from testing identical bearings under given loads/speeds to determine the ratings at which 90% of the bearings are still operational.

How Static Load Capacity Determines Bearing Life and Performance

One way to look at a bearing’s static load capacity: it’s essentially the bearing’s maximum weight limit at rest. Of course, you also have to consider the effects of sudden impact loads or shock loading (such as machine emergency stops), which can damage bearings and raceways just like exceeding the weight limit will. The major issue that occurs when exceeding static load capacity is brinelling.

Brinelling causes permanent indentations in the bearing raceway as the metal is deformed under an excessive load. As you can imagine, any amount of deformation within these precision bearing components impairs the bearing’s overall performance and drastically reduces its service life. Brinelling prevents the bearings from rolling smoothly, which results in machine chatter or excessive vibration. Excessive noise and persistent rattling are other common resulting issues.

How Dynamic Load Capacity Determines Bearing Life and Performance

Dynamic load capacity is mostly determined by the load rating, the load magnitude, the bearing speed, and the lubrication conditions. Because these conditions are constantly changing, choosing an optimum bearing type to accommodate dynamic loads means you have to consider the most extreme end of operational conditions if you want to maximize service life.

For example, higher speeds mean more wear. Heavy loads combined with high speeds further exacerbate any wear issues. Dynamic loads also include irregular vibrations and shocks, which add complexity to the load calculations but must be accounted for to ensure reliability. 

Ultimately, we calculate a hypothetical dynamic equivalent load, which gives us the expected life of the bearing if it were subjected to a constant level of combined radial/axial loads. It’s a delicate balancing act of choosing reliable, high-performance bearings that do the job dependably without adding excessive costs to your equipment.

Quality American Manufacturing and Bearing Distribution Since 1933

BSC is one of America’s leading and longest-standing manufacturers of industrial bearings and other power transmission products. By carefully considering your equipment application and static/dynamic load requirements, we will help ensure you receive the highest quality bearings optimized for your specific performance needs.

If you have any questions regarding the static and dynamic load conditions of your unique application, get in touch with the experts at BSC!

Industrial bearings come in many different types and configurations. The conventional ball bearings that most commonly come to mind are only the tip of the iceberg. We use many other uniquely specialized bearing types to accommodate the complex performance requirements of modern machines and equipment throughout today’s industrial sector.

As a case in point, Bearing Service Company regularly manufactures and distributes both standard and custom configurations of:

• Industrial Ball Bearings
• Tapered Roller Bearings
• Tension Leveler Units
• Pillow Blocks and Take-Up Units
• Linear Bearings
• Cylindrical Roller Bearings
• Thrust Bearings
• Z-Mill Bearings

Customers new to the world of industrial bearings sometimes aren’t aware of the complete list of options available to best accommodate their unique use cases. To that end, we’ve compiled a basic overview comparing common industrial bearing types, along with some of their performance advantages and typical applications.

Ball Bearings

Ball bearings are the most conventional type of rolling-element bearing used in a wide range of industrial applications. They find many diverse applications in the factory and in the field, commonly used to support many types of rotating shafts, axles, or other components while reducing friction and facilitating smooth motion.

Conventional ball bearings consist of small, spherical balls that roll between the inner and outer raceways, allowing for low-friction rotation. Industrial ball bearings are essential components in numerous industrial machines and equipment.

Advantages of Industrial Ball Bearings:

• Exceptionally low coefficient of drag – promotes less wear, minimum maintenance, and a longer service life.
• Relatively simple in design – further facilitates reliability and a lower overall cost.

Cylindrical Roller Bearings

Cylindrical roller bearings are a type of rolling-element bearing commonly used in various industrial applications to support rotating shafts or axles while minimizing friction and facilitating smooth motion. These bearings consist of cylindrical rollers, with or without a cage, designed to distribute loads and reduce friction of force in the radial direction.

Advantages of Cylindrical Roller Bearings:

• Engineered for reliability – the cylindrical bearing design resists damage, fatigue, and shock better than ball bearings.
• Cylindrical roller bearings have a simpler design and can generally tolerate small amounts of misalignment better than conventional ball bearings.

Thrust Bearings

Industrial thrust bearings (common specific types being thrust ball bearings and thrust roller bearings) are a specific type of rolling-element bearing designed to support axial (thrust) loads, which are forces applied parallel to the axis of rotation. Some common types include:

• Thrust Ball Bearings
  • Angular Thrust Ball Bearings
• Thrust Roller Bearings
  • Tapered Roller Thrust Bearings
  • Spherical Thrust Roller Bearings
• Thrust Needle Bearings

Unlike cylindrical bearings, which are designed primarily to handle radial loads (perpendicular to the axis of rotation), thrust bearings are optimized to withstand and transmit axial loads while minimizing friction and facilitating smooth motion. These bearings are crucial in various industrial applications with significant axial loads, such as cranes and mining equipment.

Advantages of Thrust Bearings:

• Industrial thrust bearings are designed for extremely low friction and smooth operation.
• Ideal for supporting high axial loads in various industrial equipment applications.

Z-Mill (Sendzimir) Bearings (Back-Up Bearings)

Z-mill or Sendzimir bearings, also commonly called back-up or backing bearings, are specialized rolling-element bearings used in modern metalworking. Typical applications include cold rolling mills and other industrial mill operations that produce rolled steel products.

Back-up bearings are designed to withstand the extreme operating conditions and heavy loads involved in the industrial metal rolling process. In typical mill operations, the roller bearing provides immense pressure to the workpiece metal, shaping it and reducing its thickness as it passes through the mill. Precision-built Z-mill bearings are critical to ensuring that the work rolls continue to rotate smoothly and reliably. As such, the bearing components are specially engineered to meet the challenges of severe working conditions, including extremely high loads and mechanical stress.

Spring Bearings (Eich Bearings)

Spring bearings (commonly referred to as Eich bearings) is an extremely resilient, flexible roller bearing for the roughest applications. This unique industrial bearing design exhibits the greatest possible degree of resistance to the effects of heat, dirt, and shock loading, and can also be installed without difficulty in many problem areas. It also offers compact envelope dimensions.

Advantages of Spring Bearings vs. Conventional Anti-Friction Bearings

Extremely resistant to damage from accumulated dirt and debris, spring bearings clean themselves due to spiral grooves designed into the bearing races. These grooves essentially act as a worm­ screw conveyor that forces debris to the outside of the race while simultaneously facilitating relubrication.

Spring bearings are engineered for superior thermal stability: the flexible races grow and shrink back to their original size through repeated heating and cooling cycles, thus maintaining an internal radial clearance that corresponds to the operating temperature. Due to the unique design of spring bearings, the thin wall section of its races allows the bearing to be installed in places where other non-friction bearing types are often not possible.

Quality American Manufacturing for Industrial Bearing Products Since 193

BSC is among the nation’s leading manufacturers, distributors, and repair sources for virtually all types of industrial bearing projects. Founded in 1933, we provide industry-leading experience and a more reliable supply chain solution for your critical bearing components.