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The optimum shaft coupling for your application
At abp, we focus on torsionally rigid, flexible shaft couplings as a connecting element between the motor and transducer. Our shaft couplings transmit forces backlash-free and angularly synchronous. Shaft couplings from abp – this means high torsional rigidity and minimal restoring forces. The resulting very low load on the shaft bearings considerably extends the service life of systems and machines.
Our product groups in the field of shaft couplings
Shaft couplings from abp – from our catalog or as custom-made products. Over 25 years of experience, close communication with you as our customer, and innovative developments ensure the smooth operation and long service life of our products in your applications.
Shaft coupling from A to Z
The shaft coupling is an essential mechanical component in mechanical and plant engineering. It serves to connect two shafts to each other and thus transmit torque between two rotating elements, such as a primary drive unit and a machine component. This connection can be rigid, elastic or flexible.
Misalignments, vibrations and shocks caused by installation inaccuracies or thermal expansion can be compensated for by using a shaft coupling.
A shaft coupling from abp is virtually maintenance-free and performs its task with high precision throughout its entire service life. Depending on the design, mechanical, thermal or electrical decoupling can be guaranteed.
On this page, we have compiled all frequently asked questions about shaft couplings for you. Are you looking for further information? Contact us now—we will be happy to advise you personally!
- What is a shaft coupling?
- What is a shaft coupling used for?
- What types of shaft couplings are there?
- What are the basic types of shaft couplings?
- What types of shaft couplings are available?
- What should be considered when selecting a shaft coupling?
- For which industries and applications is a shaft coupling from abp suitable?
- Which coupling is suitable for high speeds or high torques?
- How does a shaft coupling work in applications with stepper motors and linear axes?
- How do you measure the required shaft diameter and length for the correct selection?
- How can I correctly measure misalignment to select the right flexible coupling?
- How can I tell if a clutch is worn out or needs to be replaced?
- What norms and standards apply to shaft couplings in Germany?
- What role does torsional stiffness play in the selection of a shaft coupling?
What is a shaft coupling?
A shaft coupling is a mechanical component that mechanically connects two shafts to transmit rotational movements and torques. This product serves to compensate for minor misalignments and radial, axial and angular misalignments between the shafts and to minimise vibrations in order to enable smooth and precise power transmission.
Shaft couplings are available in various designs. A distinction is made between rigid shaft couplings, flexible shaft couplings, torsionally rigid but flexible shaft couplings, switchable shaft couplings and safety couplings. They can be equipped with a clamping hub, key and threaded pin to ensure secure mounting and fastening.
A shaft coupling from abp can be used in numerous industrial applications, such as in mechanical engineering, automation, or drive solutions, to efficiently connect drives and machine components. There are different types of couplings: rigid, flexible, and semi-rigid couplings, each of which meets specific requirements.
What is a shaft coupling used for?
Alignment errors in drive technology can be attributed to manufacturing and assembly tolerances as well as bearing play and temperature influences. Such misalignments sometimes lead to considerable bearing loads. The result is increased wear and premature failure of the system.
The use of a shaft coupling from abp can compensate for these misalignments and reduce bearing loads to a minimum. This considerably extends the service life of systems and machines.
What types of shaft couplings are there?
There are a variety of shaft couplings – also known as shaft connections, torque couplings, drive couplings, connecting couplings or, more generally, mechanical couplings. A basic distinction is made between five main types:
- Rigid couplings that connect two shafts without flexibility or misalignment compensation. There is no compensation for misalignment here. These couplings are very robust, e.g. flange couplings.
- Flexible couplings can compensate for radial, axial or angular misalignments and dampen vibrations, e.g. claw couplings, double loop couplings.
- Torsionally rigid, flexible couplings compensate for radial, axial or angular misalignments but are torsionally rigid. These are used in precision measuring tasks. Examples include metal bellows couplings.
- Switchable couplings do not compensate for misalignments, but can be switched on/off (decoupled) as required. Examples include spur gear couplings and electromagnetic couplings.
- Safety couplings protect against overload and can prevent major damage to machines. Slip clutches or our BKXSP safety coupling are used for this purpose.
Within these types, there are different designs such as bellows couplings, spiral couplings, claw couplings, or spur gear couplings, which are used depending on the application requirements and alignment conditions. When selecting a coupling, parameters such as diameter, length, permissible speeds, and the required torque should be taken into account.
As a provider of drive solutions, we at abp not only offer suitable products and complementary accessories, but also advice and services to further improve your drive solution.
Basic types
What are the basic types of shaft couplings?
Designs
What types of shaft couplings are available?
Depending on the application requirements, there are various designs that differ in their properties. The following list contains the most common designs of shaft couplings, including a brief product description:
Bellows couplings (also known as metal bellows couplings) use a flexible metal bellows to transmit torque without backlash while compensating for radial, axial, and angular misalignments. They are particularly precise and are suitable for applications in precision engineering or measurement and testing technology.
Double loop couplings consist of two flexible loops that provide excellent compensation for radial, lateral, and angular misalignments. They also provide thermal and electrical insulation.
Spring couplings use spirally wound springs as the power transmission element. They are elastic, enable smooth torque delivery, and are preferably used when vibrations need to be dampened and sensitive components need to be protected.
Spring disc couplings use thin, springy stainless steel discs as compensating elements. They transmit high torque while simultaneously compensating for misalignment. These couplings are very torsionally rigid and are often used in high-precision servo and positioning applications.
Claw couplings consist of two claws connected by a plastic ring gear. Plastic ring gears in various Shore hardnesses are used as damping elements. The claw coupling dampens vibrations and shocks and is widely used in automation and conveyor technology.
Corrosion-resistant A4 stainless steel couplings are made of highly resistant, rust- and seawater-proof stainless steel. They are suitable for use in aggressive environments, e.g. in the chemical, pharmaceutical or food industries, and offer a long service life even under difficult conditions.
Hygienic couplings made of FDA-compliant plastic are specially designed for use in the food and pharmaceutical industries and are primarily used in filling systems, conveyor belts and packaging machines.
Nickel bellows couplings are characterized by extremely high torsional stiffness combined with minimal restoring forces. They are ideal for high-precision and highly sensitive measuring tasks.
Slip couplings have an adjustable slip torque that allows controlled slippage when the permissible torque is exceeded. This protects the mechanical drive from damage.
Safety couplings have an integrated safety backup: if the bellows break, internal claws interlock so that transitional operation and regular shutdown of the system are possible.
Multi jaw couplings transmit torque via tooth flanks. They are self-centering, repeatable, and ideal for the precise transmission of high torques in both directions—perfect for applications with limited space.
Beam couplings have a slotted plastic element between the hubs, which gives them a good combination of torsional rigidity and misalignment compensation. For this reason, they are often referred to as slotted couplings. Also available as a single-piece aluminium version. They are low-maintenance and suitable for medium to high torques.
Heavy-duty spiral couplings are helix couplings with a different milling pattern, enabling them to achieve higher torque, more even power transmission and improved vibration damping – ideal for high-performance industrial applications.
Helical couplings are manufactured from a single piece and ensure backlash-free transmission of rotary motion. They optimally compensate for misalignment and are universally applicable – available in various materials when corrosion resistance or electrical conductivity is important. They are also known as beam couplings.
Special solutions couplings are individually designed and manufactured to provide tailor-made solutions for specific applications – from special diameters and lengths to special materials and torque requirements.
Criteria
What should be considered when selecting a shaft coupling?
- Shaft misalignment: Consider whether your shafts are perfectly aligned or if they have small misalignments. Depending on the degree of misalignment, you may need a flexible shaft coupling or a flexible shaft coupling that can compensate for these errors.
- Torque and power: Determine the maximum torque that the shaft coupling must transmit and the required power. The coupling must be dimensioned for these values in order to ensure reliable and safe power transmission. There are also solutions such as shaft couplings with torque limitation, which can disconnect the connection between a driving and a driven shaft if the torque limit value is exceeded.
- Operating conditions: Take into account the environment in which the coupling is used. Factors such as temperature, humidity, chemical influences or mechanical stresses can influence the choice of materials and the design of the shaft coupling.
- Material: Shaft couplings are often made of aluminum, steel or various stainless steels. Depending on the requirements, these materials offer various advantages, such as lightness, corrosion resistance and high strength.
- Area of application: The specific area of application of the shaft coupling plays a decisive role. For example, applications in medical technology often require hygienic shaft couplings, while automation places different demands on flexibility and vibration damping.
- Design and space requirements: The size and shape of the shaft coupling must be adapted to the available installation space.
Applications
For which industries and applications is a shaft coupling from abp suitable?
Shaft couplings from abp Antriebstechnik are used in a wide range of industries. Typical areas of application are:
- Food industry: abp shaft couplings are used in filling, packaging and processing machines. These are applications where hygiene requirements are particularly important and hygienic shaft couplings with FDA-compliant components are often necessary.
- Automation: In automated production systems, abp shaft couplings ensure the precise transmission of movements and forces, for example in robots or conveyor belts.
- Plant and mechanical engineering: Shaft couplings are essential components in machines and plants for reliably transmitting torque between different machine modules.
- Bearing and conveyor technology: A shaft coupling from abp can be used to connect conveyor belts, storage and lifting systems and to compensate for misalignment.
- Positioning systems: For precise movements in positioning machines, e.g. in electronics or semiconductor production, a high-precision shaft coupling from abp is indispensable.
- Laser technology: In laser technology, our shaft coupling ensures precise movements and alignment of laser optics or positioning.
- Packaging industry: A shaft coupling from abp can help to transmit precise movements in packaging machines, for example when sealing or labeling products.
- Renewable energies: In wind turbines or biogas plants, the abp shaft coupling transmits forces and compensates for thermal and mechanical expansion.
- Drives and robotics: Shaft couplings are key components in robots and drive systems and are used to transmit movements flexibly and precisely.
Which coupling is suitable for high speeds or high torques?
How does a shaft coupling work in applications with stepper motors and linear axes?
In systems with stepper motors and linear axes, backlash-free shaft couplings enable precise torque transmission and exact position control. These couplings compensate for shaft misalignments and ensure that the rotary motion of the stepper motor is transmitted precisely. They are often used in automation, robotics and drive technology where maximum precision and power transmission are required.
Measuring
How do you measure the required shaft diameter and length for the correct selection?
The shaft diameter is measured using a precise calliper (preferably digital). It is necessary to measure at several points on the shaft to ensure that there is no ovality.
The length (or installation length of the coupling) is determined by the available installation space between the shaft ends.
At abp, we provide all the necessary information on our product subpages so that you can see immediately whether the coupling is suitable.
How can I correctly measure misalignment to select the right flexible coupling?
In order to select a suitable flexible coupling, it is necessary to precisely determine the misalignment between the two shafts. This misalignment affects how much stress is placed on the coupling and how long it will last. If it is not determined correctly, premature wear or machine failure may occur.
There are three main types of alignment errors, which can occur individually or in combination:
Radial misalignment (parallel misalignment): The shafts are parallel to each other but are offset laterally. This misalignment is measured with a dial gauge or parallel gauge at several positions around the circumference. The largest measured distance is then decisive for the selection.
Angular misalignment: The shafts are not parallel, but form an angle. This is determined using a feeler gauge or by measuring the gap at several points around the circumference of the coupling. The difference in the gap dimensions then indicates the angular misalignment.
Axial misalignment (change in length): The shaft axes are misaligned in terms of length (too far apart or too close together). In this case, the distance between the two shaft end faces is measured using a depth gauge, distance gauge, or caliper. A reserve should be planned for thermal expansion of the system so that the coupling does not seize up.
How can I tell if a clutch is worn out or needs to be replaced?
The condition of a shaft coupling can be crucial to the operational safety of a system. To avoid costly downtime, it is necessary to check for wear on a regular basis.
Many problems can be seen with the naked eye or heard during operation. Typical signs of wear are:
- Play or rattling noises when changing the direction of rotation – indicates worn elastomer elements or worn hubs.
- Visible cracks, breaks, or corrosion on elastomer or metal bellows parts.
- Irregular running or vibrations that were not there before.
- Overheating of the clutch during prolonged operation.
In addition to visual inspection, measurements should be carried out at regular intervals. Test steps and measurements are:
- Misalignment measurement (radial, axial, angular) – to check whether the shafts are still correctly aligned.
- Vibration analysis – to detect imbalances or incipient bearing and coupling wear at an early stage.
- Torque monitoring – some modern systems use sensors that automatically sound an alarm if the transmitted torque increases unusually.
These tests are particularly necessary in systems with high speeds or critical processes (e.g., food production or chemical industry).
Standards
What norms and standards apply to shaft couplings in Germany?
In Germany, various standards apply to ensure that dimensions, performance data, and safety requirements are met. This guarantees the interchangeability of couplings from different manufacturers and reduces the risk of misuse.
- DIN 740 – for mechanical couplings, especially types, terms and characteristic values.
- DIN EN ISO 14691 – International standard for industrial shaft couplings, which takes into account test procedures, torque specifications, and service life, among other things.
- ATEX Directive (for potentially explosive atmospheres) – required in chemical, pharmaceutical, or food processing plants.
- FDA or EU Regulation 1935/2004 compliant materials – required when couplings come into contact with food.
These standards provide designers with the necessary dimensions, tolerances, and load limits. If you are unsure which standards apply to your applications, please contact us and we will help you select the right coupling.
Torsion spring position
What role does torsional stiffness play when selecting a coupling?
The torsional stiffness (also known as torsional rigidity) is a decisive characteristic when selecting a shaft coupling, as it describes the extent to which the coupling deforms elastically under torsional load (torque). It has a significant influence on the precision and dynamics of the power transmission.
Role of torsional spring stiffness in the selection process:
- Precise torque transmission:
- A high torsional spring stiffness ensures that torque is transmitted with virtually no twisting. This is important for applications where precise motion control is required, e.g. in CNC machines or measuring systems.
- Couplings with low torsional stiffness can lead to delays or inaccuracies during fast movements or load changes.
- Vibration damping:
- High torsional spring stiffness is less damping and can amplify vibrations, therefore less suitable for unstable loads.
- Couplings with low torsional stiffness are more flexible and can better absorb vibrations or shocks in the drive system. They are suitable for applications with alternating loads, e.g. in conveyor systems or pump drives
- Dynamics and acceleration:
- In highly dynamic applications such as servo drives, high torsional spring stiffness is essential as it enables rapid changes in movement without delay.
- Torsion spring stiffness plays a lesser role in slow, smooth movements.
- Service life of the clutch and adjacent components:
- If the torsion spring stiffness is too low, deformation can lead to higher loads on the clutch and adjacent components.
- Choosing the right torsional spring stiffness protects the coupling from overload and reduces wear.
- Compensation of misalignments:
- Couplings with high torsion spring stiffness are usually less flexible when compensating for axial, radial or angular misalignments.
- Couplings with moderate to low torsional spring stiffness are therefore more suitable for systems with larger misalignments.
The torsional stiffness is a key factor in the performance and service life of the shaft coupling.
However, it should always be considered in conjunction with the restoring forces:
The following applies here: The torsional spring stiffness must be as large as necessary.
und die Rückstellkräfte müssen so klein wie möglich sein.
A careful analysis of the requirements (e.g. torque, offsets, vibrations) is essential in order to select the right coupling.
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Our products are developed in close dialog with our customers and combine their requirements with our solution expertise. For this reason, we at abp see ourselves not only as consultants, but also as partners and reliable companions.
