外文文献（一）外文原文Front axle general is in the front of the bus, also known as steering axle or drive bridge. Automobile front axle is the last important assemblies, including the steering knuckle kingpin, steering, front beam and other components. Front axle through the suspension and frame, used to support the ground and the frame between the vertical load, but also bear the braking force and lateral force and the force of torque, and ensure that the steering rotation right movement. The axle is connected with the frame through the suspension, support most of the weight of vehicle, and wheel traction or braking force, as well as the lateral force after suspension to frame. In the car used in the steering bridge, the stress condition is more complex, so it should have enough strength. In order to ensure the wheel turns to the correct positioning of angle, make manipulation of light and reduce tire wear, steering bridge should have enough stiffness. In addition, should also try to reduce the weight of the bridge. In short, because of the automobile in the running process of the front axle, the abominable working environment, complicated working condition, the load is alternating load, thus the parts easy to fatigue cracking and even rupture phenomenon. This requires that the structural design must have enough strength, stiffness and resistance to fatigue failure of the ability.The front axle is the main load-bearing parts: the front axle, my company has a tubular and forging type two structural forms, but mainly to forging type mainly. The front ends of each with a fist shape bold part as the kingpin of the site installation. In both sides of the spring support for partial surface, used for the installation of steel plate spring and accessories. Need note here is: U type bolt passes through the front mounting holes need matter beneath the back nut in, often can appear with the front axle sleeve back band interference problem. Why can appear such problem? Design is a problem, because the front dorsal ribs affects front axle load, therefore must have a certain size requirements, and if both before and after the U bolt distance design is too small, not enough gap assembly will appear above problem. Two technical problems, technical problems in two cases. The first is the front dorsal rib symmetry is not good or mounting hole symmetrical degree and easy to cause the problem; the second is that some host plant in order to avoid the vulnerable, without taking into account the reality of the product and blind to the sleeve outer diameter. Kingpin: is the impact of vehicle performance of main parts. Kingpin has stop groove, pin lock bolt through the stop groove masterPin fixed on the front axle kingpin bore, so that it cant move can not move axially. Knuckle pin machining accuracy is very high, my company is one of the parts of key control. Steering knuckle: steering knuckle is the main steering part of front axle. It uses the main pin and the front axle is hinged by a pair of axle bearing supporting hub combination, to achieve the function of turning. Brake assembly: is the realization of the wheel brake main component, a brake oil and gas brake two forms. Implemented in the vehicle brake command, brake friction plate through the expansion and brake drum machining surface contact friction realization of vehicle brake. Front axle brake option is very critical, if the choice is undeserved, can appear before and after the brake force is not a match, the braking force is not up to the requirements of many problems. Hub combination : by two rolling bearings mounted on the steering knuckle, drive the rotation of the wheels. At the same time with the friction plate to form a friction pair, to realize the brake wheel. Arm: straight rod arm, tie rod arm, respectively, and a straight rod assembly and the tie rod assembly. Formed a steering mechanism and a steering trapezoidal mechanism. The steering mechanism to complete the vehicle steering, steering trapezoid determines the vehicle inside and outside corner is reasonable. The tie rod assembly: is to adjust the beam before the main parts. The rod body is made of seamless steel tube manufacturing, both ends of the spherical hinge joint structure is the joint assembly, by a thread after the installation of the tie rod arm, the rod body is adjustable, so as to adjust the toe. Front axle under the front of the car weight, the car forward thrust from the frame to the wheel, and with the steering device arranged on parts make joint type connection, the implementation of the automobile steering. The front axle is the use of both ends of it through the main pin and the steering knuckle is connected to the steering knuckle, swing to realize vehicle direction.In order to make the running vehicle has good linear driving ability, front axle should meet the following requirements: in order to make the running vehicle has good linear driving ability, front axle should meet the followi