拖拉机变速箱箱体快速设计方法与软件开发

针对目前拖拉机变速箱箱体产品开发周期长、设计与制造成本高的问题，该研究提出了一种基于知识的拖拉机变速箱箱体快速设计方法。首先，研究并建立箱体设计知识库、推理机制及参数化模型；然后，运用Visual Studio 2015的MFC编写快速设计系统的人机交互界面，联合SQL Server2012、Creo4.0完成快速设计系统与知识库、模型库的连接，建立拖拉机动力换挡变速箱箱体快速设计系统，并进行实例验证；最后，运用ANSYS workbench18.1对系统输出模型进行有限元仿真分析，箱体最大等效应力为206.19 MPa，最大变形为0.450 mm，最大间隙变化量为0.007 8 mm，最大错移量为0.026 mm，一阶固有频率为369.48 Hz，与ZF公司相同传动方案产品相比，箱体质量减少了28.8 kg。结果表明：该系统能高效、快速地完成拖拉机变速箱箱体开发，系统设计的拖拉机变速箱箱体具有良好的强度、刚度、密封性与动态特性，产品质量更轻，这对于缩短产品开发周期、降低设计与制造成本具有重要意义。

Rapid design method and software development for tractor gear box

Design knowledge of tractor transmission housing is lacking at present. Particularly, there is no systematic design flow to support the specific design for the transmission housing in a tractor. The lack of design knowledge and the less evaluation of performance can lead to a long development cycle of products, unstable design quality, high cost of design and manufacturing for tractor transmission housing. In this study, a knowledge-based rapid design method was proposed, while a rapid design system was established for tractor transmission housing. The system was verified by a case study. A finite element method was used to analyze the data of system design, compared with a commercial products in the same transmission scheme. Firstly, the detailed design process of tractor transmission housing was summarized on the extensive knowledge in this field; Secondly, design knowledge was obtained from some national standards, enterprise design specifications and theoretical books, and then the knowledge was divided into the principle class and instance class, which were expressed by production and frame representation, respectively. A knowledge base was established in the platform of SQL Server2012. A top-down design method was explored in a skeleton model. A parametric modeling was carried out in the multi-information Skeleton Model. A hybrid reasoning method was used based on the rule and case using MFC of Visual Studio 2015. The human-computer interaction interface and bottom reasoning mechanism of system were compiled to complete the connection with knowledge base and model base, and further to establish the rapid design system for the transmission housing of power shift in a tractor. The proposed system was also applied to the specific design in the transmission housing of power shift with a rated power of 110 kW. Finally, the rear-suspended farm tools lifting, emergency turning and one-wheel hanging were selected as the typical working conditions of the whole vehicle, while, the forward-first gear four-wheel-drive creeping and reverse-first gear four-wheel-drive creeping were selected as the typical working conditions of the transmission. A platform (Ansys workbench 18.1) was used to simulate the output model of system, where the maximum deformation was 0.450 mm, the maximum equivalent stress was 206.19 MPa, the maximum gap change was 0.0078 mm, the maximum offset was 0.026 mm, and the first natural frequency of transmission housing was 369.48 Hz, indicating that excellent characteristics, including the strength, rigidity, sealing, and dynamic in the transmission housing. Compared with a commercial products in the same transmission scheme, the height of transmission housing was reduced by 28 mm, and the mass was reduced by 28.8 kg, indicating a higher material utilization. The results demonstrated that the proposed system can be used to realize the knowledge-based rapid design of tractor transmission housing. The finding can provide a significant reference to shorten the design cycle, while improve the design quality.