Drive shafts can be classified into different categories according to their important components-universal joints.If the universal joint is in the direction of twisting, is there obvious

The flexibility can be divided intorigidityUniversal joint drive shaft and flexible universal joint drive shaft.The former relies on the hinged connection of parts to transmit power, while the latter relies on elastic parts to transmit power, and has the effect of buffering and damping.Rigid universal joints can be divided into non-Constant velocity joint(Such as cross shaft universal joints), quasi-constant velocity joints (such as double joints, three-pin shaft universal joints) and constant velocity joints (such as球笼Type universal joint, ball fork type universal joint).Constant velocity and unequal velocity refer to whether the rotational angular rate of the driven shaft is equal when the driven shaft rotates with the driving shaft. Of course, the average of the driving shaft and the driven shaftRotating speedAre equal.A universal joint whose angular velocity of the main and driven shafts is still equal when the angle between the two shafts changes is called a constant velocity universal joint or a constant angular velocity universal joint.They are mainly used for steering drive axles, disconnected drive axles, etc.wheelIn the transmission device, it is mainly used forcarThe power transmission in.When the car isRear wheel driveWhen the car is driven by the front wheels, the cross shaft universal joint drive shaft is often used. For some high-end cars, constant velocity ball joints are also used; when the car is driven by the front wheels, the constant velocity universal joint is often used—the constant velocity joint is also the same. This kind of drive shaft is just a different name.

Important parts of drive shaft

　　The universal joint is on the drive shaft of the carThe key components. inFront engineOn rear-wheel drive vehicles, the universal joint drive shaft is installed on the

Output shaft and drive axlemain deceleratorBetween the input shafts; while the front-engine front-wheel drive vehicle omits the transmission shaft, and the universal joint is installed between the front axle half shaft and the wheel that is responsible for driving and steering.The car is a moving object.On a rear-drive car, the engine,clutchInstalled as a whole with the transmissionFrameWhile the drive axle is connected to the frame through elastic suspension, there is a distance between the two, which needs to be connected.When the car is running, the uneven road surface will cause bounce, load change or twoAssemblyThe installation position difference will cause the angle and distance between the output shaft of the transmission and the input shaft of the drive axle final reducer to change. Therefore, a "variable strain" device is used to solve this problem, so there is a universal Section.

　　Drive at the front and rear wheels of the engine (orAll-wheel drive) On the car, because the car is in motionSuspensionDeformation, there is often relative movement between the input shaft of the drive shaft final reducer 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 power The normal transmission, so the 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 included angle of the universal joint should be within the allowable range; c. The transmission efficiency should be high, uselifeLong, simple structure, convenient manufacturing and easy maintenance.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.

Common types

　　The cross shaft type rigid universal joint drive shaft is inAutomotive drivelineChina is the most widely used and has the longest history.The drive shaft usually refers to the cross shaft type rigid universal joint drive shaft.Cross-shaft rigid universal joints are mainly used to transfer angle changes, generally by flange fork, cross shaft with needle roller bearing assembly, universal joint fork or sliding fork, intermediate connecting fork or spline shaft fork, needle roller bearing The axial fixed parts and so on.The flange fork is generally the same asGearbox, Drive axle or other drive shafts.The flange fork is a fork-shaped part with a flange, generally made of medium carbon steel or medium carbonalloy steelOf forged parts, also usedDuctile ironSand castings and precision castings of medium carbon steel or medium carbon high-quality alloy steel.The flange fork generally has a flatFlange, There is also a flange with a trapezoidal toothed end face.The cross shaft with needle roller bearing assembly generally includes four needle roller bearings, a cross shaft, and a grease nipple.Needle roller bearings are generally composed of several needle rollers, a bearing bowl, and a multi-blade rubber oil seal (partly with a skeleton).In some needle roller bearings, there is also a circular gasket with an oil groove.nylonYes, there are also copper sheets or other materials, which are mainly used to reduce the axial gap of the universal joint and improve the quality of the dynamic balance of the drive shaft.The universal joint fork is a fork-shaped part, generally forged parts of medium carbon steel or medium carbon alloy steel, and precision castings of medium carbon steel.The axial fixing parts of needle roller bearings are generally elastic retaining rings (internal and external clamping type) for holes (or shafts), or bearing pressure plates, lock plates, bolts, etc.

　　A serious failure of the dynamic balance of the drive shaft will cause damage to related components.The most common are the clutch shell cracks and the fatigue damage of the middle rubber support.

　　The installation of the intermediate hanger of the transmission shaft is very important in maintenance.If the hanger is installed in an improper position, it will increase the running resistance and noise of the drive shaft, resulting in early damage to the bearing.When reinstalling the hanger, first do not tighten the fixing bolts of the hanger, jack the car drive wheel off the ground, hang the low gear, slowly rotate the drive shaft to make the drive shaft and the hanger automatically align, and then fix the hanger Tighten the bolts.