Technical requirements for machining of shaft parts
Dimensional accuracy The main surfaces of shaft parts are often two types. One is the outer cylindrical journal that fits the inner ring of the bearing, that is, the bearing journal, which is used to determine the position of the shaft and support the shaft. The dimensional accuracy is high, usually It is IT5~IT7; the other type is the journal that cooperates with all kinds of transmission parts, that is, the matching journal, its precision is slightly lower, usually IT6~IT9. The geometrical accuracy of shaft parts machining mainly refers to the roundness and cylindricity of important surfaces such as journal surface, outer conical surface and tapered hole. The error should generally be limited to the dimensional tolerances. For precision shafts, the geometric accuracy of the parts is to be specified separately. The mutual positional accuracy includes the inner and outer surfaces, the coaxiality of the important axial plane, the radial runout of the circle, the perpendicularity of the important end face to the axial line, and the parallelism between the end faces. The surface of the surface roughness axis has a roughness requirement, which is generally determined by the possibility of processing and economy. The method for improving the processing technology of typical shaft parts For the general drive shaft with 7-level precision and surface roughness Ra0.8-0.4μm, the process route is: normalizing-car face drilling center hole-roughing surface-fine car Surface-milling spline, keyway-heat treatment-retrofit center hole-rough grinding outer circle-finishing outer circle-inspection. Due to the poor rigidity of the slender shaft, it is extremely deformable during processing, which has a great influence on the machining accuracy and the processing quality. To this end, the following measures are often used in production to solve. Improved workpiece clamping method In roughing, due to the large cutting allowance, the cutting force of the workpiece is also large. Generally, the card top method is adopted, and the tip of the tailstock adopts an elastic tip, so that the workpiece can be freely elongated in the axial direction. However, due to the limitation of the tip elasticity, the amount of axial elongation is also limited, so the topping force is not large. There is a danger of getting the workpiece out of the top at high speed and large amount of cutting. The use of Karafa can avoid this phenomenon. When finishing the car, the double-tip method (in which the tailstock should adopt the elastic tip) is beneficial to improve the accuracy, and the key is to improve the accuracy of the center hole. The tool holder is an extremely important accessory for turning and slender shaft machining. The use of the tool holder can offset the influence of the radial cutting component during machining, thereby reducing cutting vibration and workpiece deformation, but care must be taken to ensure that the center of the tool holder is consistent with the center of the machine tool. When turning a slender shaft, the tool is often fed in the direction of the tailstock (the karaoke tool should be installed at this time), so that the direction of the force applied by the tool to the workpiece is toward the tailstock, thus causing axial elongation of the workpiece. The trend, while the Kara tool greatly reduces the bending deformation caused by the elongation of the workpiece. Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn Home Safe,Home Safe Box,Double Key Safe,Safety Storage Cabinets Uni-Sec (Ningbo) Electronics Technology Co., Ltd. , https://www.hospitalityunisec.com