基于等切削面积的大型插齿机高效加工新方法研究

Large gear is a kind of key components of heavy machineries. Shaping is the most commonly process for large gear manufacturing. The large gear shapers, as the machine tools of shaping the large gears, are precious manufacturing equipments. Since the great inertia of its reciprocating spindle, it is not suitable to improve the cutting efficiency of the large gear shaper. It has been thus a challenge of the gear machining technology how to effectively increase the efficiency. In conventional gear shaping, the pinion cuter and the gear workpiece rotate and mesh with each other with constant rotatory speed via a given speed ratio to generate the teeth and slots on the workpiece. During the conventional gear shaping, the cutting area and cutting force vary greatly at different cutting positions on the slot. Such variation causes the shaper machine working at low efficiency, and may excite vibration that will yield negative effects to the machining quality of the gear and to the shaper machine. To overcome these defects of the conventional gear shaping process, a novel gear shaping process, named "Constant cutting area based efficient shaping method for large gear shaper", is put forward in this proposal. This gear shaping process can keep the cutting area almost constant at its maximum allowable value, and thus improve effectively cutting efficiency and cutting force variation. The proposed project will research kinematics and dynamics of the gear shaping process, including dynamic modeling, stability analysis, stability condition modeling, and determination of the target cutting speed and area for the process of the shaper-cutter-workpiece process system; kinematic modeling of the gear shaping process; and dynamics based optimization of the process parameters. This research will enhance the gear shaping theorem and provide theoretical foundation for the application of the process, which is of great value in both academic and engineering.

大型齿轮是大重型装备的关键传动零件。插齿是加工大型圆柱齿轮的重要工艺方法。作为大型圆柱齿轮加工母机的大型插齿机属稀缺制造装备。由于其主轴往复运动惯量大，难以通过高速化提高效率，如何挖掘大型插齿机加工潜力，提高加工效率，已成为齿轮加工技术领域的挑战性课题。常规插齿加工，插齿刀与工件按设定转速比做匀转速展成运动，切削面积随加工位置而异，切削面积与切削力大幅度周期性波动，不能充分利用插齿机加工能力。为此，本项目提出一种基于等切削面积的大型插齿机高效加工新方法：通过连续调控圆周进给，使插齿切削面积与切削力基本恒定在目标值，实现高效加工。项目将针对该高效加工方法的运动学实现及加工参数的合理配置，研究插齿加工切削稳定性，确定目标切削速度与切削面积，进而建立高效插齿加工运动学模型；综合考虑效率与系统动力学品质，优化加工参数。研究成果将丰富插齿加工理论，为工程应用奠定基础，具有重要的学术价值和实用价值。

大型圆柱齿轮插齿机主轴往复运动惯量大，难以通过高速化提高效率。常规插齿加工中，插齿刀与工件按设定转速比做匀转速展成运动，切削面积随加工位置而异，切削面积与切削力大幅度周期性波动，不能充分利用插齿机加工能力。为此，本项目提出一种适用于大型插齿机的变圆周进给等切削面积高效加工新方法，并对其工艺规律进行了理论与试验研究。项目主要研究内容和成果如下：. (1) 基于插齿切削层几何参数分析，提出等效切削宽度和切削厚度的概念，进而建立计及名义切削厚度的非线性插齿切削力及动态切削力模型，以及插齿动力学及再生颤振模型；针对插齿展成加工的复杂性，采用相似模型与原型相结合的分析与试验方法，获取插齿切削稳定性规律；预测出低速区(冲程次数小于200次/分钟)和高速区(冲程次数2000–3000次/分钟)两个插齿切削高稳定区，二者分别对应于常规插齿和高速插齿的冲程次数范围；基于切削稳定性规律，提出等切削面积与等名义切削厚度两种变圆周进给插齿策略，构建了相应的工艺参数模型。实例分析表明，等切削面积变圆周进给插齿策略可显著提高大型插齿机加工效率，等名义切削厚度变圆周进给插齿策略对提高高速插齿效率也有一定效果。. (2) 基于齿轮啮合理论和插齿加工原理，建立插齿刀和插齿运动学模型，构建插齿切削面积的数值算法；提出插齿切削面积均匀化原理，建立等切削面积插齿加工变圆周进给规划模型，求得变圆周进给等切削面积插齿加工的插齿刀和工件齿坯的圆周进给规律；通过几何干涉分析，获得变圆周进给插齿最小让刀量。实例分析表明，等切削面积插齿较常规插齿可减少单次径向进给插齿加工冲程数38.3–40%。. (3) 以加工效率最大化为目标，提出插齿粗加工径向进给次数与进给量分配算法，实现了径向进给次数与进给量最优分配及全齿深等切削面积插齿加工。实例分析，等切削面积插齿较常规插齿可减少全齿深插齿冲程数35%。开发了变圆周进给高效插齿工艺规划系统，实现了插齿刀参数化建模、插齿加工过程仿真和切削面积计算、径向进给次数与进给量最优分配及圆周进给速度规划等功能。. (4) 采用准静态拉伸和霍普金森压杆试验获得工件材料应力-应变曲线，进而得到了高应变率下工件材料的J-C本构参数。采用塑性有限元软件Deform-3D对插齿加工插削过程进行了数值模拟，获得了插齿切削力和插削塑性变形应力、应变与应变率信息。