With the continuous development of mechanization and integrated construction in China, the scale of construction machinery industry is expanding year by year. Among them, excavator is the largest and most important plate, especially the demand growth of small and medium-sized excavator products is more obvious, and the competition is becoming more and more fierce. In addition, customers’ awareness of the quality of the guide wheel of sand casting excavator is also increasing. The guide wheel of sand casting excavator with reliable quality and low price is more and more favored by customers. As an important component of the excavator walking system, the performance reliability of the guide wheel becomes more and more important. Therefore, it is the common expectation of customers and manufacturers to solve the failure risk of guide wheels and develop products with high reliability structure.
At present, the supporting guide wheel structure of small and medium-sized excavators widely used in the construction machinery market is mainly sand casting single web (see Figure 1), but its reliability of service performance is unstable and the failure rate is high. In particular, due to the inherent defects of the sand casting process, such as sand holes, shrinkage porosity and poor grain size, the risk of unreliability of this structure is increased. In serious cases, the working face will be broken (see Figure 2), resulting in the failure of the traveling system of the whole machine. In addition, the defects produced in the process of sand casting will increase the crack tendency of subsequent heat treatment, increase the difficulty of heat treatment process, resulting in low yield and high cost. This study aims to improve the quality of sand casting, analyze each process in the process of sand casting, find the causes of the problems, and take effective improvement measures to avoid the defects caused by sand casting process.
The problem of low yield of sand casting of cast steel guide wheel with single web of excavator is studied and solved. At the same time, the design size of sand casting is further optimized through mathematical simulation analysis, and finally applied to the actual production and manufacturing to verify the correctness and reliability of the improvement scheme, which has certain guiding significance for the manufacturing industry of cast steel guide wheel.