Is the universal joint shaft and the drive shaft the same machine?

There are many friends who don't know much about machinery, thinking that the cardan shaft and the drive shaft are the same kind of machinery. So is the cardan shaft and the drive shaft the same machine? What is the difference between a cardan shaft and a drive shaft?

Due to the limitation of the axial size, the universal joint requires a relatively large declination angle. A single universal joint cannot make the instantaneous angular velocity of the output shaft and the shaft into the shaft equal, so it is easy to cause vibration, which will aggravate the damage of the machine parts. There is a lot of noise, so a variety of constant velocity joints are used. Two constant velocity joints are used for each half shaft on a front-drive car. The joint near the transaxle is the one on the inside of the half shaft, and the one near the axle is the one on the outside of the half shaft. In a rear-drive car, the engine, clutch and transmission are installed on the frame as a whole, while the drive axle is connected to the frame through elastic suspension, and there is a distance between the two, which needs to be connected. During the operation of the car, the uneven road surface will cause jumping, the change of the load or the installation position difference of the two assemblies, etc., will change the angle and distance between the output shaft of the transmission and the input shaft of the main reducer of the drive axle. Therefore, The transmission form of the universal joints of rear-drive vehicles adopts double universal joints, that is, there is a universal joint at each end of the transmission shaft. The instantaneous angular velocity of the shaft remains equal.

The transmission shaft is usually a thick and uniform shaft, its two ends are welded with a universal joint fork and a shaft head with splines, the sliding sleeve is in the middle of the transmission shaft structure, and one end of the shaft head is connected to the flange plate by splines; In the rear drive shaft structure, the sliding sleeve and the axle fork cooperate with each other, the axle fork can slide axially along the sliding sleeve, so that the sliding sleeve can slide axially, and the transmission shaft can be telescopic to adapt to the relative relationship between the rear axle and the frame during the operation of the vehicle. When the position changes, the two ends of the transmission shaft are connected with the input shaft and the output shaft respectively with a cross shaft universal joint.