The Types of Conveyor Roller Bearings

Several industries rely on high-quality conveyor systems for their daily operations, from machinery manufacturing to distribution warehouses and airports. A conveyor is like a highway system — each component works together to transport the item smoothly and efficiently. When one part experiences a setback or error, it compromises the entire system.

Roller bearings are one of these critical elements for a properly functioning conveyor. Ensuring a high-performing, functional and long-lasting conveyor system often means changing worn-out roller bearings.

We’ve compiled this complete guide to conveyor roller bearings, including why they’re important, signs it’s time for a replacement, and the different types of bearings we manufacture.

The Importance of Conveyor Roller Bearings

Conveyor roller bearings are designed to reinforce everyday stress and tension in conveyor systems. Their primary purpose is to shape the belt and support the material being transported. However, roller bearings aren’t immune to wear and tear from regular use.

That’s why it’s important to replace these elements periodically. Doing so helps conveyor rollers achieve peak performance, extends the machine’s life span and saves money in the long haul. Below are three main reasons to prioritize roller bearing upgrades.

1. Enables Smooth Rotation

Roller bearings push into the ends of conveyor rollers, allowing the rollers to rotate smoothly on their axles. Without ongoing conveyor roller bearing maintenance, they become worn and damaged over time. This causes the roller to seize up, resulting in malfunction and downtime.

Proper roller rotation is crucial for conveyor tasks to ensure an efficient plant or factory workflow. Conveyor roller bearing upgrades can also optimize the roller’s performance in specific applications or environments.

2. Reduces Costs

Roller bearings help reduce resistance to movement. When the material is transported with minimal friction, it lowers the overall energy needed for transportation. As a result, operating costs are significantly lower. Additionally, swapping out worn or damaged roller bearings helps you avoid the cost of replacing the entire roller.

3. Extends Service Life

Roller bearing replacements can increase the life span of your conveyor system. In an open-cast mining environment, for instance, conveyor rollers encounter harsh operating factors, such as:

Intense weather conditions like snow, rain and high humidity
Heavy loads
Vibration and shaft deflection stresses
High rotating speeds

High pollution from mining environments makes it easier for impurities to compromise the bearing point — potentially causing premature conveyor failure and shortening its life span. To ensure maximum performance, reliability and service life for your conveyor system, roller bearing replacements are essential.

Different Types of Conveyor Roller Bearings

No matter your work environment or applications, reliable roller bearings for your conveyor system are integral. If you’re looking for high-quality roller bearing replacements, our team at Rolcon can assist you.

Our bearings include the following features:

Seals: Seals help block out contaminants while retaining grease within the bearing. These seals can contain felt, nylon, rubber, Teflon® or Mylar®, depending on the bearing type.
Shields: Shields also help prevent contaminants from entering the bearing. Generally manufactured with steel, they can either be used on their own or in conjunction with a seal.
Ball retainer: Ball retainers support ball bearings and keep them evenly spaced. They also help reduce noise and extend the bearing’s life span.
Flanged: Flanges are situated on the bearing’s outer race. They create a fixed bearing extension from the end of the tube. Flanged conveyor bearings can’t be recessed into tubes.
Unflanged: Unflanged bearings have cylindrical bodies that can be fully pressed into a tube when needed.
Set-screws: These components lock the inner race onto the axle.

As a leading manufacturer of custom conveyor rollers, we have a wide range of system components for a multitude of industries, operations and roller types. We can point you to the right conveyor roller bearings for your unique specifications. Let’s look at the four types of bearings we offer for conveyor rollers below.

1. Precision Bearings

While precision bearings are ideal for any conveyor system speed, they’re generally used for transporting heavy materials and loads or for speeds exceeding 400 revolutions per minute (rpm). Precision bearings are available shielded or sealed.

Sealed bearings are self-enclosed, locking out debris and trapping lubrication — unlike unsealed or open-face bearings, which need regular lubrication and additional maintenance to prevent premature failure. Standard sealed bearings contain high-grade rubber bonded to a metal washer, which typically consists of chrome or stainless steel.

Conversely, shielded bearings feature metallic enclosures instead of rubber seals. Their shields attach to the outer ring and rotate with it, maintaining a close running clearance to the inner ring. Shielding provides an additional protective barrier to prevent damage and malfunction, particularly in hot or dusty environments.

Our precision bearings come oiled or grease-packed. They feature hardened and ground balls, retainers and raceways. They’re classified as ABEC-1 bearings. The Annular Bearing Engineering Committee (ABEC) scale is an industry standard for bearing tolerances. The ABEC ratings are 1, 3, 5, 7 and 9.

ABEC-rated bearings have considerably lower noise levels and longer service lives. They can accommodate conveyor applications of up to 600 feet per minute. The higher the rating, the stronger the tolerance.

Bearings must achieve at least an ABEC-1 rating to classify as precision bearings. Otherwise, their tolerances are considered too loose. Our precision roller bearings offer tighter tolerances than other types, withstanding higher speeds and weight capacities.

2. Semi-Precision Bearings

Our semi-precision bearings typically accommodate higher-speed conveyor system applications of up to roughly 400 rpm. They feature hardened steel balls and raceways, along with a sturdy retainer to separate the balls. They tend to provide longer life spans and less noise than non-precision roller bearings.

Some other benefits semi-precision bearings have over their non-precision counterparts include:

More capacity
Higher speeds
Stronger seals
Machined metal housings with tighter tolerances
Ball retainers to keep the balls evenly spaced and separated

3. Non-Precision Bearings

Our non-precision conveyor roller bearings are most suitable for slow-to-moderate speed system applications. They have carbon steel balls, stamped outer races and ground raceways. Generally, they don’t last as long as our precision and semi-precision bearings. They also tend to be noisier.

We offer two types of non-precision bearings — unground crimped and unground press-fit. Our unground crimped non-precision bearings include the following features:

Zinc-plated for mild corrosion resistance
Most cost-effective
Suitable for lower speeds
Lowest coefficient of friction
Easiest to turn
Stamped metal housing with loose tolerances
Full complement of non-separated balls

Meanwhile, our unground press-fit bearings feature:

Zinc plates for mild corrosion resistance
Higher capacity and longer roller life than crimped bearings
More sealing options
Stamped metal housing with loose tolerances
Full complement of non-separated balls

4. Commercial-Grade Stainless Steel

Our commercial-grade, stainless steel conveyor bearings are highly effective in corrosive material handling environments. Featuring 300 stainless steel balls and machined raceways, these bearings can support light-to-moderate loads and high-speed conveyor system applications.

Types of Roller Bearing Lubrications

Rolcon also offers different lubricants for roller bearings. We can help you find the ideal type based on your daily applications and needs. Our bearing lubricants include:

Grease-packed: Grease-packed roller bearings are commonly used in powdered or humid applications. The standard grease temperature range is -10-225 degrees Fahrenheit. Light oil lubrication is often used for gravity applications since it rotates more easily. It’s usually the standard bearing lubrication for numerous industries.
Oiled: Our oiled lubricants are ideal for gravity applications requiring a low coefficient of friction. The standard oil temperature range is 0-200 degrees Fahrenheit.
Re-greaseable: Re-greaseable roller bearings have the same features as grease-packed bearings. However, they also include a drilled inner race or extended back closure. This enables more grease through the fitting on the end of the axle without separating from the roller. The conveyor’s frame thickness determines the regrease hole location. Grease-packed roller bearings can tolerate harsh environments and power conveyor applications.

Signs It’s Time to Replace Your Conveyor Bearings

Numerous factors can indicate the need for a roller bearing replacement. Below are five signs it may be time to switch out your bearings.

1. Abnormal Sounds

If you notice an unusual grinding, squeaking or screeching sound coming from the bearing, this likely means it’s time to replace it. A howling or screeching sound — particularly on cylindrical bearings — that increases with speed can result from excessive radial clearance. If you notice a metallic sound that fades temporarily after you grease it, this can indicate a poor-quality lubricant.

In some cases, you might hear a crunching sound, especially when you move the bearing by hand. This can emerge from dust contamination or a deformed bearing. It could also mean the rollers, balls, bearings or raceway surfaces have experienced scoring. Scoring can occur on bearings from metal-on-metal contact or heat damage after the lubricant film wears down.

A chattering sound audible at both low and high speeds often means the rollers on a bearing are knocking into each other.

2. Jerking or Vibration

If you observe abrupt jerking or vibration when the shaft is rotating within the bearing, an upgrade is likely in order. A vibratory sound ranging from a gentle buzz to a roar — which increases in pitch and volume with higher speed — should be addressed promptly. However, remember that a minor buzzing is natural in larger bearings.

Intense jerking or vibration can stem from various factors, such as a deformed bearing, a poorly shaped shaft, vibrating parts or brinelling (the permanent indentation of internal raceways). Brinelling is usually caused by excessive loads or shock, dropping the machinery during handling, improper mounting and other factors.

3. Excessive Play in the Bearing

Excessive preload or overload in the bearing can cause multiple conveyor system damages. For instance, the bearing cone bore polishing may experience creeping, a phenomenon where a bearing’s surface starts to slip. It may have also experienced contact wear from poor lubrication or cone bore concentration from a tight preload setting.

You might also notice fatigue spalling from excessive loads, which creates a thin film of lubricant. Fatigue spalling — also called “pitting,” “flaking” or “peeling” — is a type of surface damage affecting the metal or its finishes. It often develops cracks in the running surfaces. When objects travel over these fractures, pieces of material flake and break away.

Two main types of spalling include:

Point surface origin spalling: This spalling results from raised metal or debris exceeding the lubricant film’s thickness.
Inclusion origin spalling: Inclusion origin spalling results from hard inclusions, such as oxides, in bearing steel.

4. Cosmetic or Functional Damage

Rust, corrosion and other visible damage to the bearing or seals can signify the need for a replacement. Occurrences like spalling, scoring and peeling can cause noticeable irregularities in appearance.

In addition to surface damage, you may encounter functional problems with your conveyor system, like seized-up rollers, chain issues or rollers that don’t spin properly. As mentioned previously, one damaged component can interfere with the entire system. When you notice these types of malfunctions, it’s time to change these parts.

Internal damage can derive from a variety of factors, such as:

Foreign materials: When foreign materials like fine abrasive particles enter the conveyor system, they can damage the bearings. A lack of proper sealing and maintenance can make these internal components more vulnerable to damage from foreign debris.
Deformations: Deformed roller bearings can occur for various reasons. For instance, the bearing cones may encounter rib face deformation due to metal flow from excessive heat. This can lock up the bearings completely, causing the rollers to skew and slide from side to side.
Cage damage: A bearing cage — also called a retainer or separator — holds rolling components in the correct orientation to keep them from grouping together. It can come in multiple materials, depending on the manufacturing process. Cage damage can result from a dropped or improperly installed bearing. It often causes skewed and grouped rollers, a compressed cage ring and difficulties during installation or use.
Handling damage: Handling damage is just as it sounds — damage from rough handling during installation or transport. It often causes nicking or denting in the impact area.

5. Safety Concerns

In addition to preventing significant operational downtime, you should also replace critically damaged roller bearings to avoid safety hazards for workers and operators. When rollers seize up during use, they can develop sharp edges. These projections can snag clothing or body parts. They pose risks to people around the machine and can permanently damage items during transportation.

Conveyor roller systems must also uphold multiple safety guidelines from the Occupational Safety and Health Administration (OSHA). If your conveyor system creates hazards for others or compromises existing safety precautions, it’s important to replace your roller bearings and any other damaged parts.

Ask Us About Roller Bearings

Having dependable conveyor roller bearings is vital for smooth machine performance, service life and cost savings. At Rolcon, we manufacture a variety of conveyor roller bearings suited to different conveyor system applications. Catering to many industries, we have the skills to meet small and large requirements alike.

Offering over 30 years of expertise, we produce multiple conveyor rollers, sprockets, roller chains and bearing assemblies. We offer a wide range of roller sizes accommodating most popular conveyor manufacturers. We can also build and customize a roller to your unique needs.

Our team is also proud to offer competitive pricing and quick delivery. Most standard orders ship within one week and we expedite delivery for rush orders.

Let us help you give your conveyor system the upgrade it needs. Browse our selection of replacement conveyor roller bearings and assemblies and get a quote today! If you need assistance in finding suitable roller bearings for your specifications, please contact our experts at any time.