Coupling misalignment is divided into deflection misalignment, parallel misalignment and comprehensive misalignment. Misalignment of the deflection angle means that the end face of the coupling is deviated, and the axis lines of the two half couplings are at an angle, which generates an exciting force in the rotating state to induce a vibration response. Parallel misalignment means that the axis lines of the two half couplings are not on the same straight line, but are kept parallel to each other for a certain distance, which produces a vibration response in the rotating state. Comprehensive misalignment is the most common misalignment phenomenon in actual rotating machinery. It has both deflection misalignment and parallel misalignment, which is a combination of the two.
During the manufacturing process, the end face is not perpendicular to the axis line or the center line of the end face bolt hole is not concentric with the journal due to process or measurement. In the installation process, after tightening the connecting bolts (tooth sleeve bolts), the rotating shaft is deformed. At this time, there is a large sway in the journal. Sometimes, due to the difference in the tightening force of the connecting bolts in the circumferential direction of the coupling, it can also cause the same situation as the deflection of the end face of the coupling. During operation, if the working conditions change drastically, such as in the load process, when the load is brought to a certain value (that is, the shaft torque increases to a certain value), the coupling will be misaligned and the shaft alignment state will change , The vibration response of the rotor connected by the coupling will undergo abrupt changes. The torque of the shaft system changes a lot in an instant, which has an impact on the torque-transmitting coupling, causing the coupling to be misaligned with each other, and the shaft alignment state changes.
