Rigid Coupling
Rigid Coupling in Motion Control Applications
Rigid couplings, sometimes also called muff or sleeve couplings, were originally known as simple and economical components used to connect two shafts directly. In the past, rigid couplings were rarely considered for servo applications because they were considered inappropriate for the required characteristics.
However, today, less rigid coupling, especially those made of aluminum, have gained popularity in motion control applications thanks to their high torque, good rigidness and lack of kickback. This rigid coupling has the ability to transmit torque without rotation to the loaded shaft. However, because they cannot compensate for misalignment, using these couplings on a misaligned frame can cause premature failure of the shaft, bearings, or the coupling itself.
Rigid coupling are also not suitable for operation at very high speeds because they are less able to adjust to thermal changes in the shaft due to high speeds. However, if misalignment can be controlled well, rigid couplings provide excellent performance in servo applications.
Product
One of the often overlooked benefits of rigid couplings is their ability to help align shafts in misaligned systems. By loosening the engine mounts and related components, and connecting the shaft with a rigid coupling, the shaft can be adjusted more precisely. Once the axles are properly installed, the mount can be refitted, creating a more harmonious system.
A rigid coupling works by clamping two shafts together, making them operate as one unit. However, unlike flexible couplings, they are not designed to accommodate shaft misalignment. Rigid couplings are available in a variety of designs, both with and without keyways, to connect supported shafts. One-piece designs are usually attached tightly to the end of the shaft and reinforced with bolts, while two-piece designs can be installed and removed at any time without special tools.
Some three-piece designs also allow these couplings to be mounted on one shaft while the other parts remain free, providing additional flexibility in the installation and disassembly process.
Important Features in Gesture Control Applications
In motion control applications, there are several critical factors that a rigid coupling must address to ensure optimal performance. One of the most important is that the coupling must be designed in such a way that it does not introduce additional misalignment into the system, which could damage the lines and seals.
Precise shaft alignment can be achieved by ensuring that the holes are sharpened with precision. This roughening helps maintain the alignment of the holes on the two shafts, as well as correcting any that may occur during the installation process. This also improves contact between the shaft and clutch, so that torque can be transmitted more effectively.
Precise Installation and Custom Design
Most large clamp style rigid couplings are designed with the cap bolts positioned close to each other. This design, when installed with a crosspiece, helps strengthen the coupling’s grip on the connected shaft. During installation, it is recommended to tighten the bolts gradually so that the circular pressure created is more even and the installation becomes more sturdy.
Various types are available on the market, each with certain advantages depending on the power transmission requirements and mechanical application.