1. Difficulties in processing automobile transmission shafts
Automobile drive shaft is a rotating body with high speed and few supports, so the dynamic balance of it is very important. Generally, the drive shaft of an automobile must undergo a dynamic balance test before leaving the factory and it is then adjusted on a balancing machine. For a front-engine rear-wheel drive car, the rotation of the transmission is transmitted to the shaft of the final reducer. It can be several sections, and these sections can be connected by universal joints. The role of the automobile drive shaft is to transmit the power of the engine to the wheels together with the gearbox and drive axle, so that the automobile can finally generate driving force.
Apart from having the characteristics of a slender shaft part, the transmission shaft has a relatively large diameter difference on both sides of the part, resulting in a large difference in the linear velocity at both ends of the part. Since the drive shaft needs to run at high speed during the operation of the automobile, and at the same time transmit a large torque, not only the drive shaft is required to have good dynamic balance performance, but also the parts have high fatigue strength. However, this kind of parts are prone to bending and vibration on account of their poor rigidity during the actual cutting process, and it is difficult to obtain good machining accuracy and surface roughness. In addition, the thermal diffusion is poor and the linear expansion is large during the machining process. Under the influence of thermal deformation and cutting force, the workpiece is easy to bend and easily processed into a drum shape. This kind of parts is a difficult point in processing in the production period. It is necessary to take hard-top measures in the processing technology plan to obtain better processing results to ensure the processing performance of the parts. At present, the rapid development of the automobile manufacturing industry has put forward high-quality and efficient requirements for the processing of automobile transmission shaft parts.
2. CNC machining technology and processing steps of automobile transmission shaft
The spindle of the cnc turning lathe contains steps and inner holes, which can fully reflect the characteristics of shaft parts, so the spindle is now used as an example in the following part.
(1) Drill the center hole at both ends of the forging blank, and rough the outer circle with several large steps;
(2) Perform quenching and tempering;
(3) For each step of semi-finished car, the outer circle and length are left margin, and then take the center frame car to the total length;
(4) To make the inner through hole of the drill shaft on the center frame;
(5) Keep out the taper holes at both ends, insert the head at both ends, and drill the center hole to prepare for grinding;
(6) Finish the outer circle and step plane of each gear, put the grinding allowance, and the groove on the outer circle of the car, and chamfer;
(7) Grind the outer circle and step plane of each gear to the defined size;
(8) Process each thread on the cnc turning lathe after assembly.
3. Advantages of cnc turning lathe processing automobile transmission shaft
The processing of automobile transmission shafts is usually based on the use of cnc turning lathe. The cnc turning lathe has much higher accuracy than ordinary lathes and can be processed completely and automatically without human operation. Even the drive shafts in Chevrolet cars are processed by the cnc turning lathe. According to the technological characteristics of automobile drive shafts, the processing equipment adopts general-purpose machine tools, namely ordinary lathes, vertical milling machines, and cylindrical grinders.
In addition to the above equipment, more automation equipment can be used to help and solve manual operation problems in the processing of automobile drive shafts. From the perspective of enterprise labor costs and labor safety, the realization of automated production and unmanned workshops will surely become the trend of the equipment processing industry in the future.
(1) The number of tooling is greatly reduced, and complex tooling is not required for lathe processing of automobile transmission shaft. If you want to change the shape and size of the drive shaft, you only need to modify the drive shaft processing program, which can be applied to new product development and modification.
(2) The lathe has stable machining quality, high machining accuracy and high repeat accuracy.
(3) The production efficiency is higher in the case of multi-variety and small batch production, which can reduce the time of production preparation, machine tool adjustment and process inspection, and reduce the cutting time due to the use of the best cutting amount.