Modelling, simulation and compensation of thermal effects by hobbing gears

在1480优先计划的研究项目中，对滚刀齿轮的热引入问题进行了研究。最终目的是使无冷却剂的大齿轮滚齿的条件。由于干式滚齿产生的高热量，使齿轮质量不断恶化。由于这个原因，该行业正在使用非生产性湿滚加工。与干切削相比，冷却剂的使用对环境和制造成本有不利影响。采用干式滚齿加工大型齿轮，有必要研究热流密度对工件的影响。滚齿通常是大齿轮加工链的最后一步。在这一步骤中，形式和位置的偏差可能会产生，并且无法再得到补偿。因此，这里需要特别注意。在滚齿加工过程中，有多个齿轮齿相互接触。在这一步骤中，芯片的几何形状在每个牙齿上都是不同的。这使得对工件进行单齿接触分析变得困难。从而开辟了一条模拟路径，使单热源分析和有限元模拟成为可能。在项目的第二个阶段，应将第一个阶段的成果转移到实际的滚齿加工中。实验研究的重点是滚刀热条件及其对齿轮质量的影响。实验研究了滚刀过程中的热条件及其对齿轮质量的影响。在这种情况下，使用了铂金温度计和红外摄像机。并对齿轮的变形进行了有限元模拟，以推广计算结果。之后，获得的知识将转化为风电行业的大型齿轮。IFQ的实验结果验证了IWW的仿真。采用有限元法描述了热传导过程，并计算了局部和全局温度梯度。通过解析和半解析模型，保证了工艺参数之间的联系和变化参数的可转移性。根据在项目的第一阶段创建的经过验证和验证的替代模型，将转移到真正的滚齿加工。因此，热变形的计算将是可能的。这导致了第三个项目时期，在此期间确定了补偿的可能性。通过模拟齿轮变形，可以估计该工艺的可行性。因此，可以采用不同的补偿方法来避免大齿轮的热偏差。

Within the research project of the priority program 1480, the heat introduction into hobbed gears is investigated. The final aim is to enable the conditions for hobbing large gears without coolant. Due to the high heat quantity which is caused by dry hobbing the gear quality is deteriorating. For this reason the industry is using the nonproductive wet hobbing process. Compared to dry cutting, the coolant usage implies detrimental effects to environment and the manufacturing costs. To adopt the dry hobbing process for large gears, it is necessary to investigate the effect of the heat flux on the workpiece. Hobbing is oftentimes the last step in the process chain for large gears. In this step deviations in form and position could accrue and cannot be compensated anymore. For this reason special attention is needed herein.In the hobbing process, there are multiple gear teeths in contact. During this step, the chip geometry is different on every single tooth. This makes it difficult to carry out single tooth contact analysis on the workpiece. Thus an analogy trail is developed which enable the analysis of the single heat sources and simulation with FEM. In the second period of the project the results of the first period should be transferred to real hobbing. The experimental investigations are focused on thermal conditions in hobbing and its effect on the gear quality. The experimental investigations are focused on the thermal conditions in hobbing and its effect on the gear quality. At this platinum thermometer and an infrared camera are used. Furthermore the deformation of the gear is simulated by FEM to generalize the results. Afterward the gained knowledge will be transformed to a large gear in wind power industry. The experimental results of the IFQ serve to verify the simulation of the IWW.The method of FEM is used to describe the heat conduction and to calculate the local and global temperature gradient. The connection of the technological parameters and the transferability of changing parameters are assured by an analytical and semi-analytical model. Based on a verified and validated substitution model, which is created in the first period of the project, a transfer to real hobbing will take place. Thereby a calculation of the thermal deformation will be possible. This leads to the third project period where possibilities of compensations are identified.By the use of the simulated gear deformation, it is possible to estimate the feasibility of the process. Consequently different compensation can be used to avoid the thermal deviations on large gears.