Car drive axle design1 IntroductionThe structure form of the main reducer is based on the type of the gear and the way of the active gear and the driven gear.2 drive axleDrive axle in the tail end of the power transmission system, its basic function is to increase the torque came by the drive shaft or transmission, the reasonable distribution of power to the left and right driving wheels, and also bear role of road and the frame or body between vertical and longitudinal force and lateral force. The drive axle is composed of a main reducer, a differential, a wheel drive device and a drive axle housing.Reducer is the original motivation and independent of the working machine between the closed transmission, used to reduce speed and increase torque to meet the needs of a variety of working machinery. According to transmission form can be divided into three different for the gear reducer, worm reducer and planetary reducer; in accordance with the transmission of the series can be divided into single and multistage speed reducer; according to transmission layout situation can be divided for expansion, shunt type and coaxial type reducer. Gear reducer transmission efficiency and high reliability, long service life, maintenance is simple, and therefore the scope of application is very wide.2.1 main reducerThe main reducer gear has the spiral bevel gear type, the type of the double curved surface gear type, the type of the cylindrical gear and the worm gear and so on. At present, the main reducer gear of the automobile drive axle adopts spiral bevel gear. When the load is high, the work is stable, the noise is small, and the contact load on the tooth surface is low. So the use of single bevel gears.2.1.2 main reducer drive, driven bevel gear support formThe car driving axle design, so the use of cantilever installation. The using of the cantilever installation, ensure that the gear stiffness, active gear shaft neck should be increased, so that the distance between the two bearings than the distance of the cantilever high at least 2.5 times.3 the differential designCar in the exercise of the security, about two wheels at the same time the roll over the journey is often not equal, around two in the pressure is not equal, and the tread wear uneven, two wheel load is uneven and cause the wheel rolling radius does not match; the wheels touch the pavement conditions about different, exercises the resistance range, on the one hand will increase tire wear, power and fuel consumption, on the other hand will divert too difficult, through and handling stability is bad. Therefore, the left and right wheels of the drive axle are provided with a wheel differential mechanism.Differential is a differential transmission mechanism, used in the two output shaft torque distribution, and ensure two output shaft may rotate at different angular velocities, to ensure the driving wheels in various kinds of sports under the condition of power transmission, to avoid slipping between the tire and the ground. Differential according to its structural characteristics can be divided into gear type, convex wheel, worm wheel type and teeth embedded in a variety of forms, such as free wheel.4 half shaft For semi axis diameternot less than the diameter of the rod, the end part of the processing done slightly thicker, and appropriate to reduce spending less of the keyway depth, the tooth number must be a corresponding increase in, usually take 10 teeth (car half axle) to 18 teeth (truck half axle). The failure mode of the half shaft is basically too fatigue failure. The rod part of the axle shaft of the heavy duty truck is thicker, the outer end flange is relatively large, and the two ends of the shaft can be used as the half shaft structure with connection when no larger forging equipment is adopted, and the process is simplified by taking the same parameters. In the modern automobile half shaft, theis used quite widely, but also has the structure form of the rectangle or the trapezoidal .Shaft is one of the main parts of the machine, and all of the transmission parts of rotary motion must be installed on the axis to carry out the movement and power transmission. So the main function of the shaft is to support the rotating parts and the transmission of motion and power. According to the different load bearing, the shaft can be divided into shaft, mandrel and shaft of the third class, the relay under bending moment and bearing torque becomes the shaft. This type of shaft in the machine in the most common, only to withstand the bending moment and does not bear the torque a mandrel, the mandrel is divided into rotation and fixed mandrel mandrel two. Shaft which is only subjected to torque and does not bear the bending moment becomes the drive shaft.5 the bridge shell and the bridge shell accessories designThe main function of the drive axle housing is to support the quality of the vehicle, and is affected by the road surface reaction force and torque transmitted by the wheel, and the suspension is passed to the body. The drive shaft shell is a force transmitting member and the carrier, so the axle housing should meet the following requirements:1) with sufficient strength and stiffness, to ensure that the reducer gear mesh is normal anddoes not cause additional bending stress.2) under the premise of ensuring sufficient rigidity, as far as possible to reduce the car to improve the ride comfort.3) to ensure sufficient ground clearance.4) the structure craft is good, the cost is low.The bridge shell is a cross beam, the pivot point is located in the center of the tire, the load function in the steel plate spring seat, the average truck is used to improve the overall carrying capacity of the truck, the distance between the pivot point of the twin shaft is calculated according to the distance between the two.The maximum stress of the drive axle housing occurs near the steel plate spring. The force that causes the bending moment of the bridge shell is: the carrying capacity of the vertical load G2, the traction force F and its reaction torque M. And car shift when the tire lateral force Y2 external force in the drive axle housing, in order to simplify the calculation, just never sideslip BRDF is moving in a straight line calculated, and in terms of safety coefficient due consideration.The bending stress of the malleable cast iron bridge should not exceed 300m^2. The bending stress should not exceed 500m2 on the half shaft bushing and wheel axle of medium carbon alloy steel, and the shear stress should not exceed 250N/mm^2.Combines the actual situation of the vehicle, considering the overall expansion forming welding axle, so the material to consider ductility . We choose 16Mn.6 summaryThrough this design, it is now to design a product, only to feel that their knowledge is far from enough. There is a saying: it is never too late to learn. That's a bit of a point! Is my teacher, all my knowledge to learn!Through this design, the ability to check the manual has been greatly improved. Now, through the guidance of teachers, through their own practice, you can now go to the library to check the information, but also to look at what aspects of the information, the psychological is very clear, not so much as before.In other areas also have a lot of harvest, this graduation design makes me develop a meticulous work method. Before doing homework always give a lick and a promise, didn't have a bit of patience, sitting in the stool is not an under the heart, always with a fickle attitude to treat their own thing, now, I can very calm, very serious has been able to carry on. This may be to do the course design for me to leave things, this will be of great benefit to me later in the community.All in all, this design has made me a lot! thank you！轿车驱动桥设计1引言驱动桥处于动力传动系尾端，其基本功能是增加由传动轴或变速器传来的转矩，将动力合理分配给左、右驱动轮，且还承受作用路面和车架或车身之间的垂立、纵向力和横力。