According to the part characteristics of gear shaft with large aspect ratio, this paper mainly studies the processing process of slender shaft, refines the key processes of part manufacturing, summarizes the control measures of technical risks in key processes, designs the process flow, and focuses on the research of outer circle processing and inner hole processing.
1. Structural analysis
The low-pressure pinion of a unit is a gear shaft part with large aspect ratio. The length of the part is 3030mm and the diameter of the inner hole is φ 150mm, inner hole roughness ra3.2, runout 0.5mm, journal outer circle φ 240mm, workpiece journal tolerance 0.029 mm, journal runout 0.012mm, cylindricity 0.007mm, shaft diameter roughness Ra0.4. Taking the low-pressure pinion as the research subject, the manufacturing research of gear shaft with large aspect ratio is carried out.
2. Process design analysis
The precision of low-pressure pinion journal is high, which has high requirements for equipment and process methods. At the same time, in the machining process, it is necessary to strictly control the clamping and alignment mode, explore reasonable cutting parameters, reduce cutting stress, reduce vibration and flexible deformation in machining, so as to reduce the technical risk of part manufacturing.
3. Technical difficulties and key points
By analyzing the processing requirements and structural characteristics of low-pressure pinion, the main difficult processes are journal processing, long and deep hole processing and so on. The details are as follows: the accuracy H6 grade of shaft diameter and roughness Ra0.4 can only be realized by grinding. The turning and grinding process parameters and allowance distribution will affect the final machining accuracy, which needs to be verified by relevant process tests.
The length of the deep hole is 3030mm. One clamping can not complete the overall processing, while the second clamping increases the processing error. Controlling the datum conversion accuracy is the key point in the processing process.