Gear processing process
Hot die forging is still a rough forging process widely used in automotive gear parts. In recent years, cross wedge rolling technology has been widely promoted in shaft processing. This technology is particularly suitable for more complex stepped shaft blanks, which are not only highly accurate, have a small processing margin, but also have high production efficiency.
The purpose of this process is to obtain a hardness suitable for the subsequent gear cutting process and to prepare the tissue for the final heat treatment to effectively reduce the heat treatment deformation. The material of the gear steel used is usually 20CrMnTi. The normalized fire is relatively large due to the influence of personnel, equipment and environment, which makes the cooling rate and uniformity of the workpiece difficult to control, resulting in large difference in hardness and uneven metallographic structure. It directly affects the metal cutting process and the final heat treatment, so that the thermal deformation is large and irregular, and the quality of the parts cannot be controlled. To this end, an isothermal normalizing process is employed. Practice has proved that the use of isothermal normal fire effectively changes the drawbacks of general normalizing, and the quality of the product is stable and reliable.
In order to meet the positioning requirements of high-precision gear machining, the machining of the blanks is all based on CNC lathes. The mechanical clamping does not re-grind the turning tools, which realizes the simultaneous completion of the machining of the aperture, end face and outer diameter under one clamping, which guarantees the inside. The verticality requirements of the holes and the end faces ensure that the size of the large-scale tooth blank production is small. Thereby improving the accuracy of the tooth blank and ensuring the processing quality of the rear gear. In addition, the high efficiency of CNC lathe processing also greatly reduces the number of equipment and economical.
The equipment used in the machining of the tooth part still uses a large number of ordinary gear hobbing machines and gear shaping machines. Although the adjustment and maintenance are convenient, the production efficiency is low. If the large capacity is completed, multiple machines need to be produced at the same time. With the development of coating technology, re-coating of hobs and inserts after sharpening is very convenient.
The plated tool can significantly improve the service life, and can generally increase the temperature by more than 90%, effectively reducing the number of tool changes and sharpening time, and the benefits are remarkable.
The radial shaving technology is widely used in the production of high-volume automobile gears because of its high efficiency, easy design of tooth shape and tooth shape modification requirements.
Automotive gears require carburizing and quenching to ensure good mechanical properties. Stable and reliable heat treatment equipment is essential for products that are no longer subjected to grinding after heat.
Mainly for the heat-treated gear inner hole, end face, outer diameter of the shaft and other parts to improve the dimensional accuracy and reduce the shape tolerance.