液体火箭发动机喷管螺旋槽数控加工技术

The CNC Machining Technology of Helical Groove on Liquid Rocket Engine Nozzle

作者: 专业:机械电子工程 导师:王永青 年度:2010 学位:硕士  院校: 大连理工大学

Keywords

Liquid Rocket Engine, Nozzle, CNC Machining, Changed Angle and Variable Lead, Auto-programming

        以液氧/煤油为推进剂的主推/助推发动机和空间姿控发动机是我国最新型号的液体火箭发动机,其燃烧室收敛-扩张段喷管的冷却通道为等倾角螺旋槽或变倾角变导程螺旋槽。该类零件呈现母线复杂、刚度低的特征,加工困难。因此,研究满足液体火箭发动机螺旋槽生产要求的数控加工和自动编程技术是必要的。基于微分几何原理推导了变倾角变导程螺旋槽的一般数学模型,分析了当螺旋倾角遵循常数、线性、抛物线规律变化时导程与螺旋角的函数关系。利用MATLAB软件计算获得了螺旋线离散数据,在UG环境中构建了直母线、凸/凹圆弧、样条母线回转面变倾角变导程螺旋槽实体模型,验证了其可加工性。基于等倾角螺旋线的数学模型、运动解析以及四轴联动的加工原理,利用VC++6.0开发了一套Windows环境下的等倾角螺旋槽数控加工自动编程系统。该系统包括系统初始化模块、轮廓选择及数据处理模块、仿真及图形显示模块和NC代码生成模块,其中轮廓选择和数据处理模块是核心部分。该自动编程系统可以处理直线型、圆弧型、高次曲线型和离散点型等四种典型喷管母线,并且具有不同母线线型的自动拼接功能。只要初始化相应轮廓段的参数,系统在可连续输入的模式下完成型值点计算和轮廓拼接,并在图形仿真和显示模块中检验轮廓参数是否正确。利用等弦高差法分别计算每段轮廓螺旋槽上的刀位点,并生成数控加工NC代码。在做论文期间,作者曾到机床使用厂家对所开发的等倾角螺旋槽数控加工自动编程系统进行了试验验证,实际应用表明,自动编程系统具有编程效率高、可靠稳定等优点。
    The master push engines or the booster engines and the space attitude control engines using lox/kerosene as the propellant are China’s latest model of liquid rocket engine. Coolant channel of the combustion chamber’s convergent-divergent nozzle is loxodrome helical groove or changed angle and variable lead helical groove. The helical groove is difficult to be machined for the complexity of the component’s generatrix and low stiffness. So it’s quite necessary to explore and research new manufacturing and numerical control techniques suitable for the helical coolant groove for the liquid rocket engine.Based on the principle of Differential Geometry, the text developed the mathematical model for changed angle and variable lead helical groove and analysed the function relationship between lead and helical angle in case of changes of the helical angle follow constant, linear and parabolic law. Furthermore, the spiral reinforcement discrete data was calculated through Matlab software. Finally, some new solid models of variable angle and variable lead helical groove revolution surface with straight generatrix, circular arc and spline generatrix were constructed within the UG circumstances.According to the mathematical model, movement analysis and 4-axis-simulatanous-move machining method for the loxodrome, an auto-programming system for loxodrome helical groove NC machining based on Windows using VC++ 6.0. This system includes initialization module, contour selection and data processing module, simulation and graphic display module and code generation module, among which the contour selection and data processing module is the hard core. The auto-programming system with curve auto-stitiching function can handle four typical contours:linear type, circular arc type, High-order curve-type and discrete point-type. As long as the parameter of corresponding contour segment is initialized, the system could finish data points calculation and contour splicing under continuous input mode, and check out whether the contour parameters is right in simulation and graphic display module. It also could calculate the Cutter Location separately on each contour spiral groove, using equal chord height error algorithm, and generate the NC code for numerical control manufacturing.The auto-programming system is testified to be efficient and stable through the writer’ experimental verification in factories utilizing this system during the thesis’s writing.
        

液体火箭发动机喷管螺旋槽数控加工技术

摘要4-5
Abstract5
1 绪论8-13
    1.1 液氧/煤油火箭发动机的应用与发展8-10
    1.2 数控编程技术的发展10-12
        1.2.1 数控编程技术的基本概念10
        1.2.2 手工编程10
        1.2.3 APT自动编程10-11
        1.2.4 CAD/CAM图形自动编程系统11-12
    1.3 论文的主要工作12-13
2 变倾角变导程螺旋槽的数学建模与仿真13-19
    2.1 变倾角螺旋槽的一般数学模型13-14
    2.2 典型特征母线变倾角螺旋线的数学模型14-16
        2.2.1 直母线回转面14-15
        2.2.2 圆弧母线回转面15-16
        2.2.3 样条母线回转面16
    2.3 导程与螺旋倾角的关系16-17
    2.4 仿真加工17-19
3 等倾角螺旋槽数控加工自动编程关键问题分析19-26
    3.1 引言19
    3.2 等倾角螺旋线的一般数学模型19-20
    3.3 解析型轮廓等倾角螺旋线的数学模型20-22
        3.3.1 直线型轮廓20-21
        3.3.2 圆弧型轮廓21
        3.3.3 高次型轮廓21-22
    3.4 离散点型轮廓等倾角螺旋线的数学模型22
    3.5 型值点的选取22-24
    3.6 不同轮廓间连接的坐标连续问题24-26
4 等倾角螺旋槽的四轴联动加工方法26-37
    4.1 四轴联动加工原理分析26-29
        4.1.1 采用四轴联动的必要性26-27
        4.1.2 螺旋槽加工原理27-28
        4.1.3 铣削刀具形状28-29
    4.2 机床结构29-30
    4.3 四轴联动自动编程关键技术30-37
        4.3.1 四轴联动的运动分配30-31
        4.3.2 进给速度的确定31-33
        4.3.3 刀具转速的确定33-34
        4.3.4 四轴联动各轴的坐标生成34-35
        4.3.5 片铣刀直径的选取35-37
5 Windows环境下的等倾角螺旋槽数控加工自动编程系统的设计与开发37-59
    5.1 螺旋槽加工自动编程系统的设计思路37-38
        5.1.1 编程思想37
        5.1.2 螺旋槽加工自动编程系统架构37-38
    5.2 螺旋槽加工自动编程系统的实现方法38-41
        5.2.1编程工具VC++6.0简介38-40
        5.2.2 MFC类库及DLL应用40-41
    5.3 自动编程系统的功能模块设计41-59
        5.3.1 系统初始化模块41-43
        5.3.2 轮廓选择及数据处理模块43-56
        5.3.3 仿真及图形显示模块56-57
        5.3.4 Nc代码生成模块57-59
6 加工试验论证59-64
    6.1 加工试验的准备59-60
    6.2 数控代码的生成60-63
    6.3 试验结果63-64
结论64-65
参考文献65-67
攻读硕士学位期间发表学术论文情况67-68
致谢68-70
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