The transmission shaft is slender, the supporting points at both ends are far apart, and the rigidity is not large. After long-term use (or after major repair), under the action of its own weight, the middle of the transmission shaft will be slightly bent and deformed, so that the center of mass of the transmission shaft will rotate. The center line is offset: Due to the offset, centrifugal force is generated during operation, and the centrifugal force intensifies the bending of the shaft.When the drive shaft rotates at a high speed, its own vibration period and the external force action period resonate at the same time, which causes torsional vibration during high-speed operation, accompanied by noise.

　　After long-term use, often because the shaft's rotation center does not coincide with its centerline, or the material quality distribution is uneven (the tube wall thickness is different), and the installation is incorrect or the flat block falls off, the imbalance caused will be very large. Centrifugal force, this centrifugal force can cause the shaft to bend.When the speed increases to a certain value, the bending deformation of the shaft will be close to infinity, causing the drive shaft to break, and the speed at this time is "dangerous speed". "Dangerous speed" is a dangerous state of the drive shaft. Someone also refers to "dangerous speed" as "critical speed".

• Previous page:Matters needing attention before using transmission shaft tube
• Next page:Current Status of Carbon Fiber Drive Shaft Technology