Couplings connect two shafts together. Depending on the design of the machine, this connection can be rigid, flexible or even movable, making it necessary to install a flexible or rigid Coupling. In the past, rigid couplings were considered the inexpensive, imprecise variants of couplings. They were mostly produced in-house and were not considered for servo applications due to their less positive properties. In recent years, however, a great deal of work has been invested in the development of precise, high-performance rigid couplings. Small rigid couplings made of aluminum are particularly interesting because they have a high degree of rigidity, excellent torque properties and a high degree of backlash-free operation.

We take a closer look at the rigid Couplings and show in which areas they develop their full performance.

Rigid Couplings are also known as shell couplings and are torsionally rigid. This means that they do not exhibit any torsional deformation even under heavy torque loads. When used in locations where shaft misalignment can be controlled, rigid couplings develop very good performance characteristics. If the speeds are high and cannot be controlled, thermal changes occur in the shafts. These changes occur at high speeds due to heat build-up. As rigid couplings have no flexibility, they cannot compensate for the thermal changes. For this reason, shell couplings are not used at high speeds that cannot be controlled.

If you buy a rigid Coupling in a simple design, it has grub screws. The pins are used to attach the Coupling to the shaft at specific points.

Rigid couplings with clamping hubs, on the other hand, are advantageous. They completely enclose the shaft and therefore have strong torsional holding forces without damaging the shaft. In addition, frictional locking can be prevented. Another advantage of two-part rigid couplings is that they are very easy to install and can be removed again for subsequent maintenance. No other components need to be removed for this. Conventional rigid couplings are used at speeds of up to 3000 rpm. Rigid couplings consisting of two parts, on the other hand, can be used at up to 4000 rpm, as such a coupling has dynamic compensation.

Three-part, rigid couplings are used much less frequently. If the shaft cannot be removed axially, this type of Coupling is ideal. It consists of a three-part clamping hub, which makes assembly and disassembly much easier. The three-part, rigid Coupling is also able to compensate for differences between shafts of different sizes, as the clamping connections are attached to the two shafts independently of each other.

Let’s move on to our bestsellers in the rigid Couplings range.

The manufacturers FLENDER and KTR are particularly well known for their excellent quality and unbeatable price-performance ratio.

The SIPEX metal bellows coupling comes from the manufacturer Flender. It can be used in different design variants, which ensures maximum flexibility. As a torsionally rigid Coupling, it is virtually wear-free, which is why maintenance is not necessary. The Coupling is suitable for highly dynamic applications and can be used at a maximum speed of 15,000 rpm. Areas of application include positioning applications, filling systems and conveyor technology.

The BIPEX-S also comes from Flender. It has a specific system that has vibration-damping, electrically insulating and pluggable properties. This Coupling is suitable for highly dynamic applications, compensates for shaft misalignment and has a low mass moment of inertia. It is used in filling systems, positioning applications and conveyor systems, among others.

The ROTEX claw coupling is made by KTR. It compensates for radial, angular and axial misalignments. It is a fail-safe shaft coupling that is easy to install and completely maintenance-free. On request, we can supply this Coupling with customer-specific corrosion protection. The ROTEX is used throughout industry.

Another metal bellows coupling that is one of our absolute bestsellers and therefore a real insider tip is the TOOLFLEX from KTR. It is a flexible, torsionally rigid, flexible Coupling that requires no maintenance due to its special properties. If you order sizes 55, 65 or type KN, the coupling hubs are made of steel. If the torque is transmitted at the correct angle, the TOOLFLEX can optimally compensate for angular, axial and radial misalignments.