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Mechanical power transmission: Movement types, timing belts and gears
What types of movement are there in mechanics?
There is the uniform movement wherein a body moves at the same speed at all times, and is neither accelerated nor decelerated.
Non-uniform movement occurs when the speed or direction of a body changes during the movement process, which can lead to acceleration or deceleration. There are two cases: uniform acceleration and non-uniform acceleration.
What are the types of mechanical power transmission?
There are many different types of drives and transmissions used for mechanical power transmission.
Some of these are linear drives, pulleys, ball bearings (more information in this blog), couplings (more information in this blog), 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 they cannot be used for higher torque.
- Pulleys, in turn, can absorb high torque but are usually difficult to install.
- Couplings and gears are the most commonly used types of drives because they can also transfer large torque.
- Shaft-hub connections are a good choice for high torque transfer, but they are more difficult to install than other drives.
- Swivel heads are particularly suited for high torque transfer and are also easy to install.
It is very important to select the right drive or transmission system for the application. To do this, it is crucial to determine the right component for the application and to know the different characteristics and requirements of the system.
The best way to develop an efficient drive or transfer system is to involve an expert who will select the various components that are specifically designed to meet the needs of the system. He can also be help you choose the right drive or transfer technology for your application.
What factors play a role in power transmission?
Torque is a force that acts on an object to rotate it. When a force acts on an object to rotate it, the force is called torque. Torque has different types of effects. The torque may help to increase or decrease the rotational speed of an object.
Engineers describe torsion as twisting a body resulting from the action of a torsional moment. When attempting to twist a rod along its lengthwise axis, a torsional moment will act in addition to any lateral force.
The geometrical moment of inertia, also called the second moment of area, is a common metric used in strength theory that is derived from the cross section of a carrier. It is used to calculate the deformations and stresses generated by bending and torsional loads.
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 rotation angle. It is linked to the mass of a body attached to the axis of rotation. The greater the mass and the further away the mass is from the axis of rotation, the greater the moment of inertia.
A movement with toothed pulleys, timing belts, flat belts, round belts and return pulleys
Timing belts, also known as control belts, are an essential element of mechanical power transmission. They are installed in the engines of many cars and connect the crankshaft to the camshafts.
The camshafts control the valves in the cylinders, thus transferring the force of the crankshaft to the camshafts. In order for the timing belt to function properly, it must be under high tension.
It is usually made of rubber, polyurethane or synthetic rubber. Glass fiber or aramid is incorporated in lengthwise direction to increase load-bearing capacity and service life. Some models are additionally reinforced with a nylon fabric.
They are easy to maintain, efficient and durable. The can be used to transfer force and power and also for material handling and positioning, depending on the toothing of the profile. Synchronous belts eliminate any concerns about lubrication. They are easy to replace and very durable, as they exhibit little to no elongation.
Timing Belts
Timing belts are a very popular element of power transmission, especially in engine technology. They combine the characteristics of a flat belt and a chain by engaging into the teeth on timing pulleys.
They are also called synchronous belts or control belts. They can be used to convert the motion of a drive, transmission, or parts of a machine into controlled torque. This system can have many different applications, and it can be used in different components to transfer force in a particular mechanism.
Toothed pulleys
Toothed pulleys are an elemental component in a timing belt drive and are used to transfer torque and movement from one shaft to another. They are an important component for converting mechanical energy in a system.
Tooth profile
Splines or tooth profiles are mainly used in drive technology because they facilitate interlocking power transmission between the timing belt and the timing pulley, thus synchronizing the drive shafts.
There are several types of gear profiles: Trapezoidal profile, circular profile, involute profile and parabolic profile. Of these four profiles, trapezoidal gearing is - in addition to drive technology - also used in many transport applications due to the large contact surface of the teeth.
Idlers
Idlers are an essential component in belt conveyor systems and perform a passive role for mechanical power transmission. They support the conveyor belt that revolves between a head and rear drum by making rolling contact between the support structure and the conveyor belt. As a result, they can convert the motion type and also power transmission.
Applications for timing belts and toothed pulleys
Discover the world of mechanical power transmission! There are many different ways to use movement types and conversions to efficiently transfer energy from one location to another. Timing belts and timing pulleys are some of the most common components in mechanical engineering that help machines and systems produce the necessary properties and torques.
In 3D printing
3D printers are machines that convert liquid or solid materials such as plastics, metals, sand, wax, resins, and ceramics into three-dimensional objects. The 3D models are designed and transmitted to the device with the help of software. 3D printing is then performed by layering the material onto a carrier plate.
3D printers are often utilized by industry to produce prototypes and one-off parts. They work hand-in-hand with efficient linear drives, timing belts, toothed belt pulleys and other components, where the highest precision is crucial.
Calculating the speed ratio: timing belts and toothed pulleys
When it comes to speed ratios of timing belts and toothed pulleys, you can configure everything yourself right here. Or use the PDF to calculate the correct speed ratio.
Sizing and measurement: timing belts and toothed pulleys
When purchasing a synchronous belt, consider the minimum pulley size individually to ensure that the tooth count is at or above the minimum number of teeth. It is also important that the correct preload acts on the synchronous belt to ensure the longest possible belt life. Insufficient preload can cause the belt to skip, while excessive preload will affect belt wear.
Selecting the optimum timing belt size
Depending on the type of application, different sizes and designs are available, all with the aim of providing the optimum timing belt size.
The level of power transfer depends on many factors; the exact load bearing capacity should therefore be considered and calculated individually for each specific use case. For more information on calculating synchronous belts, refer to the PDF.
Selecting the optimum pulley tooth profile
To help you select the optimum pulley tooth profile, we provide you with an overview of different profile shapes by application type in the form of a PDF file.
What to do about belt maintenance or belt breakage?
This guide will help you identify damage during belt crimping, important belt installation stresses, timing belt misalignment and other adverse environmental conditions, along with corrective and preventive actions. If you encounter problems with the drive, gearbox, torque, machine, or components, a careful analysis of the system will allow you to minimize the maintenance costs.
Normal belt wear and failure
A common error that occurs with a belt after 2 or 3 years of use is the reduction in belt tensile strength due to thread fatigue.
For belts used over an extended period of time, no additional measures are normally required to optimize their performance. However, the longevity of the belt depends on a variety of factors, including the environment, the condition of the pulleys, the power transferred, the tension of the belt assembly, the shaft alignment and the handling of the belt before and during installation.
Bending defects
Bending defects occur in locations where very high forces act on the belt tension side when the belts are placed around a very small diameter. This can cause individual fibers to reduce belt tensile strength, thus resulting in failure.
There are several causes of such damage, including improper belt operation, insufficient tension during installation, inadequate groove radii, and/or foreign objects entering the belt drive. Improper storage, poor packaging, and belt treatment can also cause belt bending before and during installation
Incorrect installation
Particularly with synchronous belts, excessive installation tension can lead to tooth shear of the belt or to tensile failure. This is often noticeable by significant wear along the contact surfaces of the belt.
Pulley misalignment
Misaligned shaft drives or conical pulleys typically have a wear-related irregular profile on the tooth flanks of the belt, resulting in irregular loads on the web areas (between the teeth).
This can cause cracks on the belt side that absorbs the most tension, and extend to the width of the belt, which eventually causes a split of the tooth profile. Further, a belt edge can exhibit significant wear due to high tractive force.
Excessive temperatures / heat
If rubber belts run at excessive or unsuitable temperatures, the rubber hardens and back tears can result from bending.
These cracks are usually parallel to the belt teeth and occur mainly on the contact surfaces (between the belt teeth). The traction cord can then frequently fail.
Quality control for timing belts. How to achieve accurate results
Our quality control of all end products ensures that the mechanical power transmission required for belt systems comply with the corresponding DIN specifications and manufacturing tolerances. These controls are carried out in accordance with national and international guidelines or based on individual consultations with customers. Test methods are used to check the different types of motion and conversions of the drives, gearboxes, machines, and torque systems and to check the components.
Configure your components
Use the MISUMI Configurator to freely configure shafts and other components.
Select the component type and set the desired specifications and features.
CAD Library
Take advantage of our extensive CAD Library to find the best assembly part for your components and applications. Download your configured component free of charge from our website.
You can then import the downloaded components into your CAD program.
Be inspired by our inCAD Library and edit your designs with our SolidWorks AddOn.
