
Couplings are essential mechanical components used to connect rotating shafts and transmit torque across mechanical systems, and they are primarily classified into two core categories: rigid couplings and flexible couplings based on structural features and functional performance. Rigid couplings create a fixed and rigid connection between two shafts, featuring simple structures and high torque transmission efficiency. They require precise shaft alignment during operation and cannot compensate for shaft misalignment or absorb vibration, making them suitable for stable operating scenarios with no relative displacement between shafts. Flexible couplings, as the more widely applied type, are equipped with elastic or movable structural elements that can effectively compensate for axial, radial and angular shaft misalignment while buffering vibration and impact loads. These couplings can be further divided into elastic element types and non-elastic compensation types, adapting to complex and variable industrial operating conditions to protect mechanical equipment and extend service life.