大规格弧齿锥齿轮宽行端铣机理及加工干涉避免策略研究

With the development of shipbuilding, oil-gas drilling and general aviation.industries, the demand for large-sized spiral bevel gears is growing. However, it is difficult to meet the demand using the current spiral bevel gears processing method. So the new processing method has to be researched to machined large-sized spiral bevel gears efficiently. Based on the traditional spiral bevel gear machining theory and the sculptured surface CNC machined technology, through using the small-diameter end milling cutter to process spiral bevel gear with high efficiency and no interference as the target,the CNC end milling method with bigger cutting strip width is proposed for machining the large-sized spiral bevel gears. Through comparing the principles between the exclusive disc milling-cutter generating tooth surfaces and CNC machining common cutters enveloping sculptured surfaces, the idea of large-sized spiral bevel gears be processed by the small-diameter end milling cutter is invented. On the basis of sculptured surfaces CNC end milling model, with the bigger cutting strip width and the integrated gear structure as the goal, the spiral bevel gear CNC end milling model will be built. According to the structure of spiral bevel gears and small-diameter end milling cutter, and space movement relationship between them when tooth surfaces are milled, the effective interference-avoiding methods can be presented. This project will solved the difficult problem of large-sized spiral bevel gears manufacture,and the situation of large-sized spiral bevel gears dependant on import will be alleviated. The research results can enrich spiral bevel gear machining theory.

由于当前的切齿方法难以满足船舶、油气钻探和通用航空等领域对大规格弧齿锥齿轮的需求量快速增加的要求，故亟须研究新型切齿加工理论和方法，实现大规格弧齿锥齿轮的高效率加工。本项目基于传统的切齿加工理论和自由曲面数控加工技术，以采用小直径盘状刀具高效率、无干涉数控加工弧齿锥齿轮为目标，提出了适用于大规格弧齿锥齿轮的宽行数控端铣加工方法。通过分析大规格弧齿锥齿轮采用专用型盘铣刀和指状铣刀加工的优势和弊端，以及自由曲面端铣加工特点，明晰了采用小直径端铣刀宽行包络实现大直径弧齿锥齿轮高效率加工的构想。研究自由曲面的数控端铣模型，以更大的切削宽度和齿轮结构的完整性为目标，建立弧齿锥齿轮的数控端铣模型。基于小直径端铣刀和弧齿锥齿轮的结构，以及切削加工时二者的空间运动关系，提出有效的加工干涉避免方法。本项目的研究成果会丰富弧齿锥齿轮的切齿加工理论，缓解大直径弧齿锥齿轮依赖进口的现状。

随着采矿、冶金、造船、电力等行业主机设备的大型化发展，对大规格弧齿锥齿轮的需求量越来越大，但是大规格弧齿锥齿轮的制造存在加工效率低、产品质量难于控制和加工费用昂贵等问题。本项目主要研究采用小直径盘铣刀数控加工大型弧齿锥齿轮的方法，提出了采用中凹盘铣刀数控端铣弧齿锥齿轮的方法。首先，根据弧齿锥齿轮的几何结构，提出了采用中凹盘铣刀五轴联动高效率加工弧齿锥齿轮的方法。基于增大刀具前倾角范围和避免刀具与齿面的干涉，将刀具底面设计为内凹圆锥面。为了避免大直径刀具与齿槽底面的严重过切，改变了传统端铣模型中刀具姿态角的设置顺序，让刀具先侧倾后前倾，主动控制刀位避免干涉。根据切触点在齿面上的位置确定刀具侧倾角避免齿底过切，以平底刀自由曲面加工理论确定刀具前倾角实现大的切削带宽。其次，基于弧齿锥齿轮和中凹盘铣刀的结构，以及端铣齿面时二者的相对位置关系，分析了可能出现的四种加工干涉：刀尖过切齿槽底面、刀底内凹干涉大轮凸面、刀尖过切已加工齿面和刀背与另一侧齿面的干涉，然后，通过刀位的主动控制和调整、刀具结构设计等提出了避免干涉的方法。最后，通过弧齿锥齿轮副的中凹盘铣刀五轴数控加工仿真与实验、齿面测量和滚动检查，验证了端铣加工和干涉处理方法的有效性和正确性。