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Development of a model to predict the machining forces in the rolling process of powder metallurgical parts using the example of gears

以齿轮为例，开发预测粉末冶金零件轧制过程中加工力的模型

基本信息

批准号：
316100692
负责人：
Professor Dr.-Ing. Thomas Bergs, since 7/2019
金额：
--
依托单位：
Werkzeugmaschinenlabor - WZL
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/316100692?language=en
关键词：
Development model predict machining forces

项目摘要

Powder metallurgical gears are porous and, therefore, achieve lower load-carrying capacities than full-dense, wrought steel gears. External transverse rolling increases the density of both the flank and the tooth root to increase their strength. The goal of this project is the development of a model which predicts the machining forces in the rolling process. Existing model, e.g. for sheet rolling, can not calculate the rolling forces due to the high complexity of the gear rolling process. This complexity originates out of the two-flanked tooth contact, the contact ratio and the continuously changing contact geometries. Additionally, the material properties are continuously changing because of the densification and work hardening. The knowing of the machining forces is crucial for the dimensioning of the tool machines and the process design in a very early state of the development. Known machining forces lead to shortened development time for both process and the tool machine itself. This is crucial since the process chain pressing - sintering - rolling is significantly shorter than the convectional, gear cutting process chain. Therefore, a fundamental development of a prediction model of the machining forces is necessary to facilitate this process chain for the industry on the long term. For the development of the model for the prediction of the machining forces in the rolling process of PM-parts the following sub goals need to be achieved: 1. Development of a constitutive material model which considers the changes in density in the rolling process. 2. A mathematical description of the penetration of tool-workpiece depending on the tool- and workpiece geometry and the process kinematics. 3. Conception and execution of analogy-tests to generate a database considering different contact conditions and recording the occurring forces 4. Development of a rolling force model bases upon the database of the analogy-tests. 5. Transferring the contact conditions of gear rolling onto the rolling force model and verification of the results. The development of a rolling force model leads to an improved understanding of the rolling process of gears and enables for a process design which meets the requirements of the machine, the process and the tools.

粉末冶金齿轮是多孔性的，因此比全密度锻造钢齿轮的承载能力要低。外横向滚压增加了齿面和齿根的密度，以增加它们的强度。该项目的目标是开发一种预测轧制过程中的加工力的模型。由于齿轮轧制过程的高度复杂性，现有的模型，例如板材轧制，不能计算轧制力。这种复杂性源于双侧齿接触、重合度和不断变化的接触几何形状。此外，由于致密化和加工硬化，材料的性能也在不断变化。在机床研制的早期阶段，对机床的尺寸设计和工艺设计来说，对加工力的了解是至关重要的。已知的加工力缩短了工艺和机床本身的开发时间。这一点至关重要，因为冲压-烧结-轧制工艺链比传统的齿轮加工工艺链要短得多。因此，从长远来看，有必要从根本上开发加工力预测模型，以促进该行业的这一过程链。为了开发预测粉末冶金零件轧制过程中切削力的模型，需要实现以下子目标：1.建立考虑轧制过程中密度变化的本构材料模型。2.刀具与工件的几何形状和加工运动学有关的刀具-工件穿透的数学描述。3.模拟试验的概念和实施，以建立考虑不同接触条件的数据库，并记录发生的力。4.基于模拟试验数据库的轧制力模型的建立。5.将齿轮滚压接触条件转化为轧制力模型，并对结果进行了验证。轧制力模型的发展有助于更好地理解齿轮的轧制过程，并使工艺设计能够满足机床、工艺和刀具的要求。