Shaft couplings - Basics and application areas

Coupling types and their selection

This blog article provides an introduction to how couplings work and the different types used today.

What is a coupling?

A coupling is a mechanical component that creates or breaks a connection between two rotating components of a machine.

Couplings are used in many machines and systems to control and monitor power transmission. The coupling can transmit the rotary motion of the drive to the connected shaft or interrupt it if required. For more information about rotary shafts, read our article on types of shafts in mechanical engineering.

There are different types of couplings, e.g. disc couplings, Oldham couplings or slit couplings, each has different properties and is suitable for different applications. A correctly adjusted and maintained coupling is of great importance for the reliability and performance of machines. In addition to their main function, power transmission, couplings can also be used, depending on the design, to compensate for axial, radial and angular shaft misalignments or to dampen shocks in mechanical systems.

How does a coupling work and what types of couplings are there?

Couplings are a widespread and frequently used component in construction. The most common types of couplings include:

Disc couplings
Jaw couplings
Slit couplings
Bellow couplings
Shaft couplings
Rigid couplings
Oldham Couplings

Depending on the application, different types of couplings are suitable for use in a mechanical system.

Disc coupling

Disc couplings can transfer high torques between two shafts with great efficiency. Disc couplings can be designed as a variant with one or two discs, via which the torque is transferred from the driving shaft to the driven shaft. They are characterized by anti-backlash nature and a pronounced torsional rigidity and are well suited for use as servo couplings in servo motors. Depending on the design, disc couplings can compensate small radial and angular misalignments. Buy disc couplings in the MISUMI web shop .

Jaw coupling

The jaw coupling is suitable for applications requiring high torque. It is often designed as an elastomer coupling, in which a plastic disk is inserted between the claw rings of the two shaft ends. This allows dampening of shocks and vibrations. A further advantage of using it as an elastomer coupling is the electrical insulation between the two connected shafts. Discover now a wide selection of jaw couplings in the MISUMI web shop.

Oldham coupling

Oldham couplings can transmit high torques between two shafts and have a very large permissible misalignment range. Due to their construction with plastic cross disks between the two body parts, they are able to compensate for a high degree of radial and angular misalignment. This makes them particularly suitable for cases where reactive forces occur. Get your Oldham couplings now in the MISUMI web shop.

Slit coupling

Slit couplings are torsionally rigid couplings that are well suited for use with servo motors due to their anti-backlash nature and torsional rigidity. Due to the slots provided, this type of coupling can compensate for axial, radial and angular misalignment to a small extent. Slit couplings are particularly suitable for utilization in stepping motors, as they can be integrated into the structure in an anti-backlash manner. Visit the MISUMI web shop and purchase high-quality slit couplings.

Bellow coupling

Bellow couplings use a rubber or metal bellows to transmit the rotation between two shafts. They are characterized by the fact that they enable an anti-backlash power transmission and at the same time can compensate for axial and angular misalignment. Bellow couplings are therefore suitable for utilization in stepping motors. Don’t miss the opportunity to purchase bellow couplings in the MISUMI web shop.

Rigid coupling

Rigid or torsion-rigid couplings consist of a continuous fitting. They are characterized by freedom from play and high torsional rigidity and can therefore be used in servo motors are used. Since rigid couplings cannot compensate for shaft misalignment, appropriate centering of the shafts is necessary.

	Coupling characteristics			Motor
Design	Anti-backlash	High torque	Permissible radial offset Permissible angular offset	Servo motors	Stepping motors Compact Servo	Universal
Disc	✓✓	✓✓	✓	✓✓	✓	❌
Oldham	❌	✓✓	✓✓	❌	❌	✓✓
Slotted	✓✓	✓	✓	✓	✓✓	❌

The following example illustrates the procedure for selecting the correct coupling and the corresponding part numbers.

Application example:

Drive motor: Servo motor with drive-side ball screw
Direction of rotation: Reverse rotation at a speed of 3000 rpm
Radial offset: 0.1 mm
Angular offset: 1°
Axial offset: 0.1 mm
Diameter of shaft bore hole on the motor side: 14 mm
Diameter of shaft bore on ball screw side: 15 mm
Total length of coupling: 60 mm or less

Select the appropriate coupling for your motor type and application. For the drive described above, an anti-backlash coupling is required, which has a radial and allows angular misalignment. Using the above-mentioned scheme for easy coupling selection, a disc coupling CPDW.
Calculate compensation torque for the coupling. Condition: Peak torque of the servo motor of 3.0 Nm and nominal torque of the servo motor of 1.0 Nm. When calculating the compensation torque with a compensation factor of 2.0 (reference value), the requirement for a permissible torque is 6 Nm or higher. This requirement is met by the Version CPDW40.
Check the coupling tolerance. The version selected in step 2 meets the necessary radial, axial and angle tolerances.
Select shaft bore hole. The required shaft bore holes of 14 and 15 mm are both feasible for the selected version. This results in the item designation being supplemented with “14” for the shaft bore d1 and “15” for the shaft bore hole d2.
Select the shaft connection method. With this coupling variant, only the fastening method via a clamp is available. Therefore, it is not necessary to make a selection.
the final review of the dimensions The total length of the selected coupling is 49.4 mm, which is within the permissible range of the requirements of 60 mm or less. The final part number is CPDW40-14-15.

Shaft couplings for every purpose

MISUMI offers the right coupling for every purpose. Thanks to the wide range of configuration options, all coupling types can be adapted to suit the respective application. The main body and other components of the coupling are made of high-quality materials such as aluminum or stainless steel and meet the highest quality standards.

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.

Configure now!

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”.

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