Application of Cold Extrusion Forming Technology On Intermediate Shaft Of Car Transmission
One of the crucial parts of the car transmission system is the middle/intermediate shaft. It’s the drive on the car transmission that’s crucial for transmitting power from the engine to the wheels for the car to moving. The production of this car part is by the use of cold forging technology. The amount of precision is needed when manufacturing the intermediate shaft is very high. That’s why car manufacturers are opting for the cold forging forming process.
Cold forging, also known as cold extrusion, is a forming process that works on work piece at room temperature. This means you don’t need to heat or de-ignite the metal you are working on. The high precision level and near net shape makes cold forging the most preferred forming technology. The process of forming a middle or intermediate shaft of the car transmission using cold extrusion is pretty simple. In this guide, we listed down the major steps:
Intermediate Shaft Cold Forging Design
The structure of the shaft is not complicated, with the part structure being symmetrical shape. Note that the material used for these shafts is 20CrNi2MoH, which has a refractive state hardness of ≤160HB. So, the strength of the material is not very high hence a relatively lower deformation resistance. The technical requirements plus the dimensions are considered, the same as the needed toughness and tolerance of the shaft.
The Intermediate Shaft Cold Forging Process and Simulation Forming
The cold forging process of the intermediate shaft is not different from other parts. The machine setup, the molds, dies, and the blanks are the same. What makes the process different is the shape and the size of the shaft. The middles step of the shaft has the largest while both ends have different diameters depending on the type of car they are used on.
The Cold Forging process
With the three parts (different diameters) to informing the intermediate diameter, the squeezing must be done with a lot of precision. You cannot start with the middle diameter, which the largest, to the smallest. The structure of the shaft will be destroyed, and the cracking possibility increased. The forming process is divided into three main steps.
The first step includes the extrusion of the two ends of the shaft. The diameters are made to be almost the same size. The middle diameter also formed but with a slightly higher value than the two ends. The next step is reducing the smallest end diameter and increasing the larger two diameters by not more than 12.2%. This helps to keep the forces constant to reduce the cracking of the material.
The third and final step is reducing the smallest diameter to the required value and increasing the other end plus the middle of the shaft at a rate of 21.6%. It is essential that these steps are followed strictly to avoid a large squeezing ratio.
The second step is the simulation process. This is the first process used to check if the production system is working fine. There are several things that go into the simulation process. One of them is checking the features of the required middle shaft have been achieved. This includes measurements, weight, and other elements. The measurements of the required shaft are taken, and the materials to be used are identified. This is one of the crucial simulations.
The second and most crucial simulation data collected are the forming forces. This is very crucial data in cold forging because it determines other factors like tool quality. Using the simulation software, you must check the forming force for forging, forming force for the material, and the shrinking neck forming forces. The distribution must be stable for the cold-forged parts to produce the required quality. At least three sequence formulation processes should provide the needed data.
The Production of Car Intermediate Shaft
With the simulation process complete and everything working fine, the next step is the production. This is where the manufacturer goes full scale depending on the orders. The process is determined by the type of metal that’s being formed. In most cases, high-carbon steel is used, and that’s some bit of heating is need to reduce hardness. The slight heating also improves the cold forging machining process.
The process is pretty straightforward and uses cold squeezing mold structure. The structure includes the universal cold forging frame, preforming, and final forming process. The processing of the final product must also include blubbing and lubrication treatment to get a fine surface.
In conclusion, cold forging car intermediate shaft is one of the reliable forming processes. The process offers maximum material utilization. We use the forge simulation software to produce near net-shaped shafts. If you are interested in cold forging, you can consult Cold Forging China