The drive shaft is composed of a shaft tube, a telescopic sleeve and a universal joint. The telescopic sleeve can automatically adjust the distance between the transmission and the drive axle. The universal joint guarantees the change of the angle between the output shaft of the transmission and the input shaft of the drive axle, and realizes the constant angular speed transmission of the two shafts.

       Universal joint

       The universal joint is a key component on the drive shaft of an automobile. The car is a moving object. In a rear-drive car, the engine, clutch, and transmission are installed on the frame as a whole, and the drive axle is connected to the frame through an elastic suspension. There is a distance between the two and needs to be connected. When the car is running, the road is uneven and jerks.

       Generally, the universal joint is composed of a cross shaft, a cross bearing and a flange fork. The universal joint is a key component on the drive shaft of an automobile. On a front-engine rear-wheel drive vehicle, the universal joint drive shaft is installed between the transmission output shaft and the input shaft of the drive axle final reducer; while the front-engine front-wheel drive vehicle omits the drive shaft, and the universal joint is installed Between the front axle half shaft and the wheels, which are responsible for both driving and steering. When the vehicle is running, the uneven road surface will cause bounce, load changes, or the difference in the installation position of the two assemblies, will cause the angle and distance between the transmission output shaft and the input shaft of the drive axle final reducer to change. "Strain" device to solve this problem, so there is a universal joint.

       In a car with front-engine rear-wheel drive (or all-wheel drive), due to the deformation of the suspension during the movement of the car, there is often relative movement between the input shaft of the drive shaft final drive and the output shaft of the transmission (or transfer case). In addition, in order to effectively avoid certain mechanisms or devices (which cannot achieve linear transmission), there must be a device to achieve the normal transmission of power, so universal joint transmission appears. The universal joint drive must have the following characteristics: a. Ensure that the relative position of the two connected shafts changes within the expected range, and can reliably transmit power; b. Ensure that the two connected shafts can run evenly. The additional load, vibration and noise caused by the angle of the universal joint should be within the allowable range; c. The transmission efficiency should be high, the service life is long, the structure is simple, the manufacturing is convenient, and the maintenance is easy.

       For automobiles, since the output shaft of a cross-shaft universal joint rotates at unequal speeds relative to the input shaft (with a certain included angle), double universal joints (or multiple universal joints) must be used for transmission. The two universal joint forks connected with the drive shaft are arranged on the same plane, and the angles of the two universal joints are equal. This is very important. In the design, the angle of the universal joint should be minimized.

       Telescopic sleeve

       In the traditional structure of the transmission shaft telescopic sleeve, the spline sleeve and the flange fork are welded together, and the spline shaft is welded to the transmission shaft tube. The new type of transmission shaft changes the traditional structure by welding the spline sleeve and the transmission shaft tube into one body, and the spline shaft and the flange fork are made into one body. The rectangular tooth spline is changed to a large pressure angle involute short tooth spline, which not only increases the strength but also facilitates the extrusion forming, and meets the needs of high torque working conditions. The tooth surface of the telescopic sleeve and spline shaft is coated with a layer of nylon material, which not only increases the wear resistance and self-lubrication, but also reduces the impact load on the drive shaft and improves the cushioning capacity.

       This kind of transmission shaft adds a tube-shaped sealing protective sleeve outside the flange spline shaft. Two polyurethane rubber oil seals are arranged at the end of the protective sleeve, so that a completely sealed space is formed in the telescopic sleeve, so that the telescopic spline The shaft is not corroded by external sand and dust, and is not only dust-proof but also rust-proof. Therefore, when assembling, apply grease to the spline shaft and the sleeve at one time, which can fully meet the requirements of use, and there is no need to install a grease nipple for lubrication, which reduces the maintenance content.