Mechanical power transmission: Types of motion, timing belts and gears

What types of motion are there in mechanics?

There is a uniform movement, where a body moves at the same speed all the time without accelerating or braking.

In the case of irregular motion, the speed or direction of a body changes during the motion process, which leads to acceleration or deceleration. A distinction is made between two cases: accelerated and unevenly accelerated motion.

What types of mechanical power transmission are there?

There are many different types of drives and gearboxes used for mechanical transmission.

Some examples are linear drives, pulleys, ball bearings (more information about ball bearings), couplings (our detailed explanation about couplings), spur gears, shaft-hub connections, and swivel heads. Each of these drives has its own advantages and disadvantages.

• For example, linear drives are very efficient, but cannot be used for higher torques.
• Pulleys, on the other hand, can absorb high torque, but are usually difficult to install.
• Couplings and gears are the most commonly used drive types, as they can also transfer large torques.
• Shaft-to-hub connections are a good choice for high torque transmission, but they are harder to install than other drives.
• Swivel heads are particularly suitable for high torque transmission and are also easy to install.

It is very important to select the right drive or gearbox system for the application. To do this, it is essential to determine the right component for the application and to know the different properties and requirements of the system.

The best way to develop an efficient drive or gearbox system is to consult an expert to select the various components that are specially developed for the requirements of the system. The expert can also help to select the right drive or gearbox technology for the application.

What factors play a role in power transmission?

Torque is a force applied to an object to rotate it. When a force is applied to an object to rotate it, the force is called torque. Torque has different types of effect. Torque can help to increase or decrease the rotational speed of an object.

In technology, torsion is described as the twisting of a body caused by the effect of a torsional moment. If you try to twist a rod along its longitudinal axis, a torsional moment will act in addition to any transverse force.

The geometrical moment of inertia, also known as the second moment of area, is a variable commonly used in the strength of materials field, derived from the cross-section of a support. It is used to calculate the deformations and stresses that occur under bending and torsional stress.

A moment of inertia describes the rotational movement of a body. It refers to the amount of energy required to rotate an object or change the angle of rotation. It is connected to the mass of a body attached to the rotational axis. The greater the mass and the further away from the axis of rotation it is, the greater the moment of inertia.

One movement with timing belt pulleys, timing belts, flat belts, round belts and guide rollers

The timing belt, also known as the control belt, is an essential element of mechanical transmission. It is installed in the engine of many cars and connects the crankshaft with the camshafts.

The camshafts control the valves in the cylinders, which transmits the power from the crankshaft to the camshafts. In order for the timing belt to carry out its function, it must run under high tension.

It is usually made of rubber, polyurethane or synthetic rubber. In the longitudinal direction, glass fibre or aramid is incorporated to increase load capacity and service life. Some models are reinforced with nylon fabric.

They are easy to maintain, efficient and durable. It can be used for both force and power transmission, as well as for material handling and positioning, depending on the toothing of the profile. With synchronous belts, you don't have to worry about lubrication. They are easy to replace and very durable, as they expand very little or not at all.

• Timing belts
• Timing pulleys
• Idlers

Timing belts

Timing belts are a very popular element of power transmission, especially in engine technology. They combine the properties of a flat belt and a chain, as they run positively in toothed pulleys.

They are also known as synchronous belts or timing belts. They can be used to convert the movement of a drive, gearbox or parts of a machine into a controlled torque. This system can be used for many applications and in different components to enable power transmission in a specific mechanism.

Timing pulleys

Timing pulleys are an elementary component in a timing belt drive and are used to transfer torque and motion from one shaft to another. They are an important component for converting mechanical energy in a system.

Tooth profile

Gear teeth or tooth profiles are mainly used in drive technology, as they enable positive force transmission between the timing belt and timing belt wheel, which synchronises the drive shafts.

There are different types of gear profiles: trapezoidal profile, circular profile, involute profile and parabolic profile. Of these four profiles, trapezoidal toothing is also used in many transport applications due to the large contact surface of the teeth, in addition to the drive technology.

Carrying rollers

Carrying rollers are an essential part of belt conveyor systems and play a passive role in the transmission of mechanical force. They support the conveyor belt running between a head and rear drum by establishing rolling contact between the support frame and the belt conveyor. In this way, they enable both the conversion of motion types and force transmission.

Timing belt and timing belt pulley applications

Take a look at the world of mechanical power transmission! There are many different ways to use types of motion and conversions to transfer energy efficiently from one place to another. Timing belts and timing belt pulleys are some of the most common mechanical components that help machines and systems to deliver the required properties and torques.

In 3D printing

3D printers are machines that create three-dimensional objects from liquid or solid materials such as plastics, metals, sand, wax, resins and ceramics. The 3D templates are designed and transmitted to the device using software. 3D printing then takes place by applying the material onto a carrier plate layer by layer.

3D printers are often used in industry to produce prototypes and individual components. In these systems, efficient linear drives, timing belts, timing belt pulleys and other components work hand and must deliver the highest level of precision.

Calculating speed ratio: Timing belts and timing belt pulleys

When it comes to the speed ratio of timing belts and timing belt pulleys - you can configure everything yourself here. Or use the PDF to calculate the correct speed ratio.

Dimensioning and measurement: Timing belts and timing belt pulleys

When purchasing a synchronous belt, it is important to consider the minimum size of the belt pulley individually to ensure that the minimum number of teeth is not undercut. It is also important to apply the correct pre-tension to the synchronous belt to ensure the longest possible service life of the belt. Insufficient pre-tension can cause the belt to jump, while excessive pre-tension will lead to increased belt wear.

Select the optimal belt size

Different sizes and constructions are available depending on the type of application to provide the optimal timing belt size.

The transmission power level depends on many factors, so the exact load capacity should be considered and calculated individually for each specific application. You can read more about calculating synchronous belts in the PDF.

Select the optimal belt pulley tooth profile

To help you select the optimal belt pulley tooth profile, we offer an overview of different profile shapes by application type in the form of a PDF file.

What needs to be done in case of belt maintenance or belt breakage?

This guide will help you identify belt crimping damage, key stresses during belt installation, timing belt misalignment and other adverse conditions, and also outlines corrective and protective measures you can take. If there are problems with the drive, gearbox, torque, machine or components, you can minimise maintenance costs with a careful analysis of the system.

Normal belt wear and failure

A common fault that occurs on a belt after 2 or 3 years of use is reduced web tension strength due to cord fatigue.

For belts used over a long period of time, no additional measures are normally required to optimise their performance. However, the belt service life depends on a variety of factors, including the environment, pulley condition, power transferred, belt installation tension, shaft alignment, and belt handling before and during installation.

Kink fault

Kink faults occur in places where very strong forces are applied to the belt tensile cords when they are placed around a very small diameter. This can cause individual fibres to reduce the tensile strength of the belt and lead to breakage.

There are several causes for this type of damage, including incorrect belt operation, insufficient tension during installation, insufficient groove radii and/or foreign bodies entering the belt drive. Improper storage, poor packaging and belt handling can also lead to belt kinks before and during installation.

Incorrect installation

With synchronous belts in particular, excessively high installation tensions can lead to tooth shears on the belt or to a tension break. This is often indicated by significant wear along the belt’s land surfaces.

Pulley misalignment

Inclined shaft drives or cone-shaped pulleys usually have a wear-related irregular profile on the belt tooth flanks, resulting in irregular loading in the web areas (between the teeth).

This can lead to cracks on the side of the belt that carries the most tension, and extend across the width of the belt, eventually resulting in splitting of the tooth profile. Furthermore, there may be significant wear on one edge of the belt due to high traction force.

Excessively high temperatures / heat

If rubber belts run at too high or unsuitable temperatures, the rubber hardens and cracking on the back can occur due to bending.

These cracks usually run parallel to the belt teeth and mainly occur over land surfaces (between the belt teeth). This can often lead to breaks in the traction cord.

Quality control for timing belts – how to achieve precise results

Our quality control of all end products ensures that the mechanical power transfers required for belt systems comply with the corresponding DIN specifications and manufacturing tolerances. This check is carried out in accordance with national and international guidelines or based on individual agreements with the customer. Test procedures are used to check the various types of motion and conversions of the drives, gearboxes, machines and torque systems and to check the components.

Configure your components

You can configure shafts and other components freely with the MISUMI configurator.

Select the component type and set the desired specifications and characteristics.

CAD library

Use our extensive CAD library to select the optimal part for your components and applications.

Find inspiration in our inCAD library and edit your designs with our SolidWorks add-on “inCADcomponents”.