复杂水冷电机壳体的铸造工艺设计及模具制造

发布时间：2019-06-24 23:38

【摘要】：随着我国社会发展,国家对发动机排放要求日趋严格,新能源发动机的需求在与日俱增,新能源发动机零部件的研发也正在受到越来越多的重视,其中电机壳体就是用于新能源机型的的一个大型关键零部件。该零件几何结构复杂,壳体壁内带循环水室,要求要有良好的力学性能和气密性。复杂壳体零件的铸造一直是铸造行业的重点与难点。砂型铸造在目前我国诸多铸造企业中是应用最为广泛的,其优点在于工艺成熟,成本低廉,但是铸件毛坯余量大,容易产生各种铸造缺陷。消失模铸造由于其无需组芯,无须拔模斜度,所以使用消失模铸造工艺的铸件具有尺寸精确,加工余量少的特点。但是消失模铸造也有着一定局限性,比如EPS泡沫模样在燃烧过程中,热解出的C原子会向金属表面渗透,使得铸件面产生碳夹杂的缺陷。而且EPS泡沫的强度比不上树脂砂芯,在造型和振实过程中容易被挤压变形,甚至塌箱。本文探讨的是如何将两种铸造方式结合并解决复杂电机壳体零件的铸造工艺难题。本文基于CAD/CAE技术对消失模的设计参数以及铸造工艺参数进行优化,采用消失模-水道砂芯组合的铸造工艺对GH电机壳体进行开发,并设计制作两副消失模模具和一副冷芯盒模具,使用UG的CAM模块对模具进行加工编程,经过调试后用生产出来的泡沫模与砂芯装配浇铸,生产出合乎产品设计使用要求的铸件。根据本文研究,得到研究结果如下：(1)消失模和砂型铸造的组合工艺是一种切实可行的铸造工艺方法,以发泡的EPS材料颗粒翻制白模来表达GH电机壳体外形,以金属模翻制水道冷砂芯来表达封闭循环水室,再将泡沫白模与水道冷砂芯组装并用干砂充实,最后进行浇铸成形。本文使用该方案,成功浇注出具有复杂外型和中空内腔的电机壳体铸件。(2)采用AnyCastiing软件对铸造过程进行模拟仿真,采用不同的工艺参数模拟铸造过程中浇注和凝固的变化过程,并对可能出现的缺陷进行预测,使工艺人员能够根据要求采取更合理的浇注方案。(3)采用参数化的CAD软件对电机壳体的模具进行设计,可以方便的调整各种参数,在不断调整各种模具参数的同时,整个设计过程可视化程度高,提高了设计的准确性和便利性。(4)使用CAM软件对模具进行编程加工,利用刀具特性,在CAM阶段可以完成一些CAD阶段的工作,比如模具的涂料层、拔模斜度、圆角等。(5)消失模铸造在振实阶段,砂粒对泡沫模型和砂芯冲击都很大,必须采取增加芯骨或其他方式来增加模型强度；并且振实前要对泡沫模型的一些半封闭位置进行特别检查,这些部位填砂不饱满会导致铸件粘砂。(6)对于多方向脱模的模具,灵活采用多活块的侧抽结构可以脱模,但是如果是人工操作的话就需要给活块设计一定的导向机构,如槽或导轨,这样才能保证人工装模的一致性。对于深腔铸铁模具的加工,采用镶拼式结构可以节约大量刀具成本,同时也节约了加工时间。
[Abstract]:With the development of our country, the country's demand for engine emission is becoming more and more strict, the demand of new energy engine is increasing day by day, and the R & D of new energy engine parts is being paid more and more attention. The motor housing is a large-scale key component for new energy models. The geometric structure of the part is complicated, and the inner wall of the shell is provided with a circulating water chamber, so that good mechanical property and air tightness are required. The casting of complex shell parts has always been the focus and difficulty of the casting industry. Sand casting is the most widely used in many foundry enterprises in China. Its advantages are mature technology and low cost, but the margin of casting blank is large, and various casting defects can be easily produced. The lost foam casting process has the characteristics of accurate size and less processing allowance due to the need of no group core and no draft angle. However, the lost foam casting has some limitations, such as the EPS foam pattern in the combustion process, the pyrolytic C-atom can penetrate to the metal surface, so that the surface of the casting can produce the defect of carbon inclusion. And the strength of the EPS foam is not better than that of the resin sand core, and the EPS foam is easy to be extruded and deformed during the molding and compaction process, and even the tank is collapsed. In this paper, it is discussed how to combine two kinds of casting ways and to solve the problem of casting process of complicated motor case parts. In this paper, the design parameters of the lost foam and the parameters of the casting process are optimized based on the CAD/ CAE technology, and the shell of the GH motor is developed by the casting process of the combination of the lost foam-water channel sand core, and the two auxiliary lost foam moulds and a pair of cold core box dies are designed. And using the CAM module of the UG to process and program the mould, and after the debugging, the produced foam mould and the sand core are assembled and cast to produce the casting which is in accordance with the product design and use requirements. The results of the study are as follows: (1) The combined process of lost foam and sand mold casting is a feasible casting process, and the foamed EPS material particles are turned to the white mold to express the appearance of the GH motor shell. The cold sand core of the water channel is turned over by a metal mould to express the closed circulating water chamber, the foam white mould and the water channel cold sand core are assembled and the dry sand is enriched, and finally the casting is carried out. In this paper, the casting of motor shell with complex shape and hollow cavity is successfully cast. (2) The casting process is simulated and simulated by using the AnyCassing software, and the process of casting and solidification in the casting process is simulated with different process parameters, and the possible defects can be predicted, so that the process personnel can adopt more reasonable casting scheme as required. And (3) the parameterized CAD software is adopted to design the mould of the motor shell, various parameters can be conveniently adjusted, and meanwhile, the whole design process is high in visualization degree, and the design accuracy and the convenience are improved. And (4) using the CAM software to program and process the mould, and using the characteristic of the cutter, the work of some CAD stages can be finished in the CAM stage, such as the coating layer of the mould, the draft angle, the fillet, and the like. (5) When the lost foam is cast in the vibrating stage, the impact of the sand on the foam model and the sand core is large, the strength of the model must be increased by adding the core bone or other means, and the semi-closed position of the foam model is specially checked before the vibration is real, The incomplete filling of these parts will result in the casting of sand. (6) For a multi-direction demoulding mould, the side-drawing structure of the multi-movable block can be flexibly used for demoulding, but if the mould is manually operated, a certain guide mechanism, such as a groove or a guide rail, is required to be designed for the movable block, so that the consistency of the manual loading mould can be guaranteed. In that proces of the deep cavity cast iron mould, a large amount of tool cost can be saved by adopting a mosaic structure, and the processing time is also saved.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM305

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