A rigid coupling is a shaft coupling used to connect two shafts at either end to transmit power. For this type of coupling, the shaft provides a fixed connection, does not require torsional flexibility, maintains shaft alignment, and provides proper bearing support. To reduce shaft deflection, the shaft support bearing should be as close to the coupling as possible. Large couplings and couplings that operate at high speeds may require balancing to reduce vibration. However, their installation is very simple.

We divide rigid couplings into three categories:

Flange couplings

Sleeve couplings

Rib couplings

Flange couplings

Flange couplings are used to connect shafts of the same or different diameters. The unit consists of 2 flange hubs that are drilled and keyed to fit the respective shafts and connected by bolts. Some have removable bushings for easy replacement. Couplings are usually made of carbon steel and can be up to 8 inches in diameter. Flange couplings are mainly used in heavy-duty applications.

Sleeve couplings

Sleeve couplings are made from a single piece of material; the factory has been drilled to fit standard shafting. Keyways are broached and set screws are installed. The shaft key transfers torque from the shaft to the coupling hub, and the set screw prevents the coupling from sliding along the shaft. Sleeve couplings are also available in clamping styles. There are two types of clamping styles: one-piece designs and split, two-piece styles. Split, two-piece couplings can be installed and removed without machine disassembly.

Ribbed Couplings

Ribbed couplings are available for heavy-duty service and consist of 2 pieces for connecting shafts of the same diameter. The coupling is bolted to both shafts. These couplings can be installed and removed quickly and easily.

In summary, the advantages of rigid couplings include low price, high torque capacity, high torsional stiffness, and zero backlash.