Last revised: February 25, 2025

Drive rollers and idler rollers are cylindrically-shaped material handling components that convey items through a machine, process, or environment. They deliver time, space, and energy efficiencies in resource handling applications. 

Drive rollers rotate via direct interaction with a motor. Internal electric motors power motorized drive rollers (MDR). Belt-driven drive rollers receive rotational energy from linked motors. Idler rollers do not receive direct mechanical input from a power source, though they may be linked into a transmission via belts or contact with other moving parts. Idler rollers also maintain or adjust tension in a transmission. They are effective for supporting conveyed materials between drive rollers and are the sole roller type in gravity conveyors.

These components support conveyor belts and control the flow of materials. They can also be situated adjacently to eliminate the use of a conveyor belt, provided the materials being conveyed have surfaces or form factors suitable for this. Drive and idler rollers can also be used to process thin substrates, such as in a printer. Uniquely-shaped roller structures are capable of steering the direction of motion of a load on a belt or handling unusual materials.  

Electric-powered, electronically-controlled drive rollers have replaced lineshaft units. Lineshaft devices require power transmitted from a central source. Early energy sources included water wheels and steam and diesel engines where the motor transmitted power via a belt, also called a lineshaft. This created constraints in the conveyor construction and placement of cylinders. As a result, the setups suffered mechanical efficiency losses given the distance from the power source.

Over the course of time, compact motors placed along a production line gained increased acceptance in lieu of lineshaft systems. The change enabled the configuration of assembly lines around industrial processes and the areas in which they were operating. This led to enhanced operational efficiency, with material transfer consuming less time and energy. Integration of modern technology in conveyor setups facilitated the introduction of space-saving solutions.

Types of Drive Rollers and Idler Rollers

Roller units support numerous options, including:

• MDRs feature an internal electric motor housed in the load-bearing cylinder. MDRs deliver precision control over product movement and superior energy efficiency over a broad range of capacities. A belt can allocate power to adjacent rollers, with one masted MDR driving multiple units.
• Belt-driven drive rollers move resources with increased speed and minimum energy consumption.
• Conveyor rollers guide conveyor belts and support the carried masses.
• Rubber-coated rollers possess a diverse set of attributes, making them suited for handling items at high temperatures, with exposure to oil, water, or corrosive chemicals.
• Impact idlers are coated with high-strength, shock-absorbing materials. The roller cores and coating minimize structural deformation from weight transfer shocks.
• Troughing idlers guide the transportation of objects on a conveyor. Idler rollers running beneath a conveyor belt form a trough that keeps loose material from falling off the belt.

Idler pulleys guide the rotation of belts in a conveying system and maintain or alter the tension in the belt.

Components 

Roller bearings are essential to drive and idler roller roller function. They minimize energy losses due to mechanical friction for a set range of load and speed handling characteristics. The surface of rollers are often coated or altered to improve performance parameters. Rubber-based coatings alter the friction, shock absorption, noise reduction, and deformation properties. Special coatings enable resistance to corrosion, mechanical wear, and temperature variations. Bulky resources found in logistics, mining, and ore processing deploy heavy duty rubber-coated elements. These items absorb impact, reduce noise, and dampen vibration.

Non-uniform shaped structures are capable of steering the direction of motion of the load on a belt. The troughed design supports the system by means of rollers positioned at inclined angles, creating troughs to prevent material spillage.

Materials

Standard products comprise of diverse materials based on functional requirements, including:

• Steel cores are integrated into units with amplified load-bearing capacity, such as pallet conveyors.
• Aluminum devices designed to cover lowest inertial ratings are suitable for precision and rapid transfer.
• Zinc- and aluminum-coated surfaces are not susceptible to rust.
• Neoprene offers resistance to weathering and petroleum-based fluids and is flame retarding.
• EPDM (ethylene propylene diene monomer) is resistant to chemicals other than petroleum-based substances.
• Buna-N (nitrile-butadiene) possesses resistance to petroleum-based fluids.
• Silicone withstands severe temperature environments.
• HNBR (hydrogenated nitrile) is unaffected by heat, oil, fuel, and ozone.
• Urethane is impervious to solvents and abrasion.

Specifications 

Considerations when selecting drive and idler rollers are broadly.

• Weight and physical shape of the load
• The device dimensions and maximum bearing capacity
• Desired speed for loading, transporting, and feeding an object on the rollers
• Operational temperature of the environment
• Exposure to water, natural oils, ozone, and petroleum-based fluids
• Expected levels of surface abrasion and wear

Features 

Drive rollers are assembled in automated modular units. These platforms feature control systems on several linked modules that authorize selective control over units in the assembly environment. A modular configuration employing sensors offers superior performance. The sensors activate the drive motors only when a load is detected, thus eliminating the need for continual operation of the setup.

Applications 

Drive and idler rollers cover a myriad of current and potential functions in multiple industries where, including:

• Aerospace parts and assembly
• Agricultural equipment
• Consumer goods manufacturing
• Electronics
• Food production
• Medical equipment
• Pharmaceuticals
• Labeling
• Lamination
• Logistics and package handling
• Mining
• Printing and presses
• Packaging
• Paper
• Woodcraft

Standards 

Drive and idler rollers are subject to a selection of standards, including:

NPFC - A-A-59955 — Conveyor, roller, gravity, dock, high-line, conveyorized

ISO 606 — Short-pitch transmission precision roller and bush chains, attachments and associated chain sprockets

Drive Rollers and Idler Rollers FAQs

How do the materials used in roller construction impact their performance and durability in various engineering environments?

The materials used in roller construction significantly impact their performance and durability in various engineering environments. Here are some key points:

Material Properties and Performance

Ceramic Rollers: These are used in environments requiring high mechanical resistance, thermal stability, and excellent corrosion resistance. For example, in the production of lithium-ion battery cathode powder, ceramic rollers must have uniform mechanical properties to withstand bending stresses and prevent deformation.

Rubber and Urethane Rollers: These materials are chosen for applications needing large contact and holding friction forces, such as in paper and plastic production. They are also used where surface finish integrity is crucial, like in the sheet metal industry.

Environmental Resistance

Buna-N (Nitrile-Butadiene): Offers resistance to petroleum-based fluids, making it suitable for environments where such exposure is common.

Silicone: Known for withstanding severe temperature environments, making it ideal for high-temperature applications.

HNBR (Hydrogenated Nitrile): Unaffected by heat, oil, fuel, and ozone, making it versatile for various harsh environments.

Corrosion and Aesthetic Considerations:

Rollers can be made from materials like stainless steel, brass, and aluminum, which offer different levels of corrosion resistance and aesthetic finishes. These materials can be further treated with finishes like metal plating or electroless nickel for enhanced protection and appearance.

Operational Considerations

The choice of material also depends on operational factors such as the weight and shape of the load, device dimensions, desired speed, and exposure to environmental elements like water and oils.

What are the specific applications of different roller materials?

The specific applications of different roller materials are influenced by their unique properties, which make them suitable for various engineering environments. Here are some insights:

Ceramic Rollers

Applications: Primarily used in the production of lithium-ion battery cathode powder.

Properties: High mechanical resistance, thermal stability, and excellent corrosion resistance are crucial for these applications. They must also maintain straightness and rigidity to prevent deformation under bending stresses.

Rubber and Urethane Rollers

Applications: Extensively used in paper and plastic production industries, graphics printing, and office printers. They are also employed in the sheet metal industry for coiling low gauge sheet metal.

Properties: These materials provide large contact and holding friction forces, are heat resistant, and protect surface finish integrity. They are ideal for applications where the material cannot sustain surface damage.

Buna-N (Nitrile-Butadiene)

Applications: Suitable for environments with exposure to petroleum-based fluids.

Properties: Offers resistance to petroleum-based fluids, making it ideal for such conditions.

Silicone

Applications: Used in high-temperature environments.

Properties: Known for its ability to withstand severe temperature conditions.

HNBR (Hydrogenated Nitrile)

Applications: Versatile for various harsh environments.

Properties: Unaffected by heat, oil, fuel, and ozone, making it suitable for demanding applications.

Metal Rollers (Stainless Steel, Brass, Aluminum)

Applications: Used where corrosion resistance and aesthetic finishes are important.

Properties: These materials can be treated with finishes like metal plating or electroless nickel for enhanced protection and appearance.

How do different roller geometries affect their applications?

The geometry of rollers plays a crucial role in determining their applications across various engineering environments. Here are some insights:

Roller Profiles

Straight Profile: These rollers are typically used in applications where uniform contact across the roller surface is required. They are suitable for general-purpose applications where the load is evenly distributed.

Crowned Profile: This geometry is designed to help in self-centering the belt or material being conveyed, reducing the risk of misalignment. It is often used in conveyor systems to maintain belt tracking.

Barrel-Shaped Profile: These rollers are used in applications where there is a need to accommodate slight misalignments or where the load distribution is not uniform. They help in reducing edge wear and extending the life of the roller system.

Material and Geometry Combination

Metallic Rollers: Available in straight or crowned geometry, these are used for heavy-duty applications where the workpieces can tolerate rough handling. They are ideal for moving higher loads.

Rubber and Urethane Rollers: These are available in straight or crowned geometry and are used in applications requiring large contact and holding friction forces. They are suitable for delicate operations where surface integrity is crucial.

Mounting and Hardware Options

Rollers can be specified with various mounting components such as bearings, set screws, bushings, bolts, keyways, or shafts. These options allow for customization based on the specific application requirements.

What are the applications of self-aligning roller bearings?

Self-aligning roller bearings are designed to accommodate misalignment and are used in applications where shaft deflection or mounting errors are expected. Here are some insights into their applications:

Accommodating Misalignment

Self-aligning roller bearings are particularly useful in applications where there is a possibility of misalignment between the shaft and the housing. This can occur due to shaft deflection, mounting errors, or thermal expansion.

High Load Capacity

These bearings are capable of supporting high radial loads and moderate axial loads in both directions. This makes them suitable for heavy-duty applications where high load capacity is required.

Common Applications

They are often used in industries such as mining, construction, and material handling, where machinery is subject to heavy loads and potential misalignment.

They are also found in conveyor systems, where they help maintain smooth operation despite potential misalignments in the system.

Durability and Reliability

The design of self-aligning roller bearings allows them to operate reliably in harsh environments, making them ideal for applications where durability is critical.

What are the benefits of using self-aligning roller bearings over other types of bearings?

Self-aligning roller bearings offer several benefits over other types of bearings, particularly in applications where misalignment and heavy loads are common. Here are some key advantages:

Accommodating Misalignment

Self-aligning roller bearings are specifically designed to handle misalignment between the shaft and housing. This can occur due to shaft deflection, mounting errors, or thermal expansion, making these bearings ideal for applications where such conditions are expected.

High Load Capacity

These bearings can support high radial loads and moderate axial loads in both directions. This makes them suitable for heavy-duty applications where high load capacity is required, such as in mining, construction, and material handling industries.

Durability and Reliability

The design of self-aligning roller bearings allows them to operate reliably in harsh environments. They are built to withstand challenging conditions, ensuring long-term durability and consistent performance.

Versatility in Applications

Commonly used in conveyor systems, self-aligning roller bearings help maintain smooth operation despite potential misalignments. They are also found in various industries where machinery is subject to heavy loads and potential misalignment.

Drive Rollers and Idler Rollers Media Gallery

References

GlobalSpec—Silicon carbide rollers for manufacturing cathode active materials for Li-ion batteries

Image credit:

Baldor Electric Company