Timing Pulleys (metric) Information

Show all Timing Pulleys (metric) Manufacturers

Last revised: February 5, 2025

Timing pulleys that are designed with a millimeter-based pitch designation. Timing pulleys mate with same-pitch timing belts in synchronous drives. Timing pulleys are used in power transmission systems where maintenance of speed ratio is an important design consideration. These synchronous belt drive systems are durable, highly efficient, and suitable for many different applications.

Metric pitch timing pulleys have a spacing or pitch based on millimeter (mm) measurements and trapezoidal or curvilinear, toothed form.

Specifications

Pitch

Pitch is the distance from one tooth’s center to the adjacent tooth’s center. Pitch choices include T pitch, AT pitch, GT pitch, HTD pitch, and super-torque pitch.

T pitch is a trapezoidal pitch available in four sizes: 2.5, 5, 10 and 20 mm.
AT pitch is a curvilinear pitch available in three sizes: 5, 10 and 20 mm.
GT pitch is also curvilinear, but available in 2, 3 and 5 mm sizes.
HTD, an acronym for high-torque drive, is also curvilinear. Sizes include 3, 5, 8, 14, and 20 mm. Both GT and HTD are registered trademarks of Gates Rubber Company.
Super-torque is a metric, curvilinear pitch with sizes ranging from 2 to 14 mm.

Force

Force is transmitted via evenly spaced grooves which mate with the teeth in the belt.

Geometry

Metric pitch timing pulleys differ in terms of the number of:

Grooves
Belt width
Length
Bore diameter
Length through bore

Materials

Metric pitch timing pulleys are made of metal, plastic and combination materials. Factors such as environmental conditions, design horsepower, operating temperature, and cost determine the best material choice.

Typically, metal pulleys are made of aluminum or steel.

Plastic pulleys are made of acetal, nylon, or polycarbonate materials.

Acetal pulleys provide chemical resistance, but melt at relatively low temperatures.

Polycarbonate pulleys have excellent mechanical properties, but can be attacked by solvents and petrochemicals.

Metric pitch timing pulleys that use a combination of materials feature plastic teeth with metal inserts.

Mounting Options

Many products include a hub which provides a shaft-attachment mechanism such as a set screw or hub clamping screw.

Set screws tighten directly onto the shaft for pulley attachment.
Hub clamping screws squeeze the inner diameter of the hub to a tight fit around the shaft.

Metric pitch timing pulleys that do not use hubs are also available. These pulleys may be pressed or adhered onto a shaft, or use a set screw whose thread is tapped into the pulley grooves. In addition, some synchronous drive belt systems use flanges to resist side forces and keep the belt from slipping off the pulley.

Standards

BS ISO 5294 — Synchronous belt drives — pulleys

JIS B 1856 — Synchronous belt drives — pulleys

Timing Pulleys FAQs

What are the quality and balance requirements for timing pulleys?

The quality and balance requirements for timing pulleys are crucial for ensuring their effective performance in engineering designs.

Quality and Finish

Standards focus on the quality and finish of timing pulleys. High-quality finishes are essential for reducing friction and wear, which can enhance the efficiency and longevity of the pulley system. A well-finished pulley surface ensures smooth interaction with the belt, minimizing the risk of damage and extending the life of both components.

Balance

Proper balance is critical for the smooth operation of timing pulleys. Imbalances can lead to vibrations and noise, which may cause premature wear or failure of the pulley system. Standards provide guidelines to ensure that pulleys are manufactured with precise balance, contributing to the overall stability and performance of the system.

What are the specific applications of synchronous belt drives in engineering?

Synchronous belt drives are used in various engineering applications due to their ability to provide precise timing and synchronization. Here are some specific applications:

Automotive Industry

Synchronous belt drives are commonly used in automotive applications, particularly in timing belts for engines. They ensure that the camshaft and crankshaft are synchronized, which is crucial for the engine's performance and efficiency.

Industrial Machinery

In industrial settings, synchronous belt drives are used in machinery that requires precise timing and positioning, such as conveyor systems, packaging equipment, and printing presses. These applications benefit from the accurate and reliable power transmission that synchronous belts provide.

Robotics

Robotics applications often require precise motion control, which can be achieved using synchronous belt drives. They are used in robotic arms and other automated systems to ensure accurate and repeatable movements.

Textile Industry

In textile machinery, synchronous belt drives are used to maintain precise control over the movement of various components, ensuring consistent fabric quality and production efficiency.

Aerospace

Aerospace applications utilize synchronous belt drives for their reliability and precision in controlling various mechanical systems within aircraft.

How do synchronous belt drive standards affect pulley design?

Synchronous belt drive standards significantly influence pulley design by providing guidelines and specifications that ensure optimal performance, reliability, and compatibility in various applications. Here are some key aspects of how these standards affect pulley design:

Quality, Finish, and Balance

Standards emphasize the importance of quality, finish, and balance in pulley design. These factors are crucial for reducing friction, wear, and vibration, which can enhance the efficiency and longevity of the pulley system.

Axial Run-out and Operating Characteristics

Standards addressing axial run-out and operating characteristics help minimize misalignment and vibration. This ensures that pulleys operate smoothly and reliably, reducing the risk of premature failure.

Limiting Values for Adjustment of Centers

Standards define the limiting values for the adjustment of centers in belt drives. This ensures that pulleys are correctly aligned and tensioned, which is critical for maintaining optimal performance and preventing slippage or excessive wear.

Synchronous Belt Drives

Standards provide specific guidelines for synchronous belt drives, which are essential for applications requiring precise timing and synchronization. These standards help in selecting the right pulley design to match the specific requirements of an application.

Automotive Applications

For automotive parts, standards ensure that synchronous pulleys meet the rigorous demands of automotive applications, where reliability and precision are paramount.

How do axial run-out standards impact the longevity of pulley systems?

Axial run-out standards play a crucial role in the longevity of pulley systems by ensuring that the pulleys operate smoothly and reliably.

Minimizing Misalignment and Vibration

Standards addressing axial run-out and operating characteristics help minimize misalignment and vibration. This is important because excessive axial run-out can lead to uneven wear on the belt and pulley, causing premature failure of the system.

Ensuring Smooth Operation

By adhering to axial run-out standards, manufacturers can ensure that pulleys are produced with precise tolerances. This precision helps in maintaining smooth operation, reducing the risk of mechanical stress and extending the life of the pulley system.

Reducing Wear and Tear

Properly aligned pulleys with minimal axial run-out experience less friction and wear. This not only enhances the efficiency of the system but also contributes to its longevity by preventing damage that could result from excessive movement or misalignment.

What is the impact of pulley quality and finish on system performance?

The quality and finish of timing pulleys have a significant impact on the performance of pulley systems in engineering designs.

Quality and Finish

The quality and finish of timing pulleys are crucial for reducing friction and wear. A high-quality finish ensures smooth interaction between the pulley and the belt, which minimizes the risk of damage and extends the lifespan of both components. This can lead to enhanced efficiency and longevity of the pulley system.

Balance

Proper balance is essential for the smooth operation of timing pulleys. Imbalances can cause vibrations and noise, which may result in premature wear or failure of the pulley system.

What is the role of axial run-out in pulley systems?

Axial run-out plays a significant role in the performance and longevity of pulley systems.

Minimizing Misalignment and Vibration

Standards addressing axial run-out and operating characteristics help minimize misalignment and vibration. Excessive axial run-out can lead to uneven wear on the belt and pulley, causing premature failure of the system. By adhering to these standards, manufacturers can ensure that pulleys are produced with precise tolerances, which is crucial for maintaining smooth operation.

Ensuring Smooth Operation

Axial run-out standards ensure that pulleys operate smoothly and reliably. This precision helps in reducing mechanical stress and extending the life of the pulley system. Properly aligned pulleys with minimal axial run-out experience less friction and wear, enhancing the efficiency of the system.

Reducing Wear and Tear

By minimizing axial run-out, the risk of excessive movement or misalignment is reduced, which in turn prevents damage and extends the lifespan of both the pulley and the belt. This contributes to the overall stability and performance of the pulley system.