Machining shaft parts on a lathe, in order to ensure the concentricity of the entire shaft at each shaft diameter, is usually done once in a single clamping process. The chuck is not loosened during the machining process. Therefore, the length of blanking is about 30mm longer than the length of the finished product, and the length of the blank is specifically used for clamping. After the workpiece is finished, it is cut off with a cutter. So this length becomes useless material.
1 Process and equipment without head material processing technology is used to drive the circular hole in the clamping end of the shaft type workpiece (round hole diameter size, shape, depth depending on the situation of self-determined), with special drive three-edge, four pyramid cone inserted into the transmission hole , adjust the tailstock with the thimble to close the workpiece by clamping. Because the transmission pyramid and the transmission hole have the function of transmitting torque and self-aligning and centering, after the clamping, the lathe spindle can transmit the rotation to the workpiece, and the workpiece can be processed and the machining accuracy can be guaranteed. This process can save 0.2 to 15kg of material head per shaft, and the weight of the thick shaft is larger, especially suitable for mass production. No head machining process can also be used for finishing car testing. The transmission pyramid is shown in Fig. 1. It is made of T8 or T9 steel. After processing, the pyramid head is quenched to a hardness of HRC62 to 64. It can be processed according to the IT standard of 7 to 8 degrees. It can be divided into large and medium according to the size of the workpiece. , Small variety of specifications, its size and taper as the case may be, for different diameters of the shaft processing, its use and clamping method shown in Figure 2. 2 Precautions The precautions for using this process are that the processing precision of the driving pyramid has a direct impact on the status and machining accuracy of the clamped clamp; when the drive is used for round holes, the bore diameter should be as large as possible without affecting the structure and strength. Increase the contact surface between the transmission pyramid and the transmission hole and the transmission torque; during the cutting process, the ejector pin must not be loosened. If the workpiece is found to have looseness and beating phenomenon, the tailstock should be tightened in time; the transmission hole should hit the centerline of the shaft to minimize the deviation. Shrinking; this process is not suitable for the processing of slender shaft parts, so the process needs to be tighter when the clamp is installed, the workpiece is subject to greater axial force bending deformation, it is only suitable for the processing of the short axis 3 Conclusion lathe no The idea of â€‹â€‹material processing of shaft parts is based on the analysis of the surface of the parts and the hole of the thimble when it is used to survey foreign imported mechanical parts. It has been studied in light of its inspiration, but the structure of its clamping fixture has not been implemented. Clear, pending further study. According to the analysis of the workpiece footprint, the workpiece has a center hole at the end of the workpiece, and six radial tool indentations are distributed around it. This is similar to the general wood-based rotary lathe machining fixture, but the clamping fixture may be more complicated. Because there is no data for the headless fixture at present, it cannot be designed and manufactured for the time being. Therefore, the use of triangular and quadrangular pyramid instead of clamping fixtures has achieved good process results and machining accuracy, and processing of triangular pyramids and quadrangular pyramids. It is easy to manufacture and easy to install. It can improve work efficiency and save materials. The problem is that there is a large radial component during strong cutting, and sometimes the plastic deformation of the contact point between the transmission pyramid and the driving circular hole is slightly loose. Therefore, it is required to adjust the tightness of the ejector in time so that it can eliminate the transmission pyramid and the transmission hole in time. The slipping phenomenon caused by the large radial cutting force to ensure the reliable connection between the transmission pyramid and the round hole of the component does not produce any looseness. Therefore, the tailstock ejector must be equipped with a device for automatically adjusting the axial pressure so that When the transmission pyramid and the part of the transmission hole contact plastic deformation, the axial pressure of the ejector automatically presses the component to the transmission pyramid, eliminating the loose phenomenon caused by plastic deformation. The device includes the pressure mechanism and the control mechanism. The structure is not yet mature and needs further study. At present, simple manual force adding and manual control methods are applied to the tailstock ejector pin to solve the plastic deformation and loosening caused by the cutting force.