Abstract: A study on the design method of downward-flipping rear doors is conducted to address the issues of material spillage, vulnerable rear doors structure, and inefficient unloading in existing off-road dump trucks cargo box in this paper. By analyzing the operation of off-road dump trucks and the advantages and disadvantages of existing rear doors structures, the paper systematically elaborates on key design aspects including the automatic opening mechanism design, hinge point optimization, movement process verification, and structural strength validation of downwardflipping rear doors. The geometric modeling method is used to determine the rotation point position, kinematic equations are established for quantitative analysis of opening timing and trajectory, and strength simulation verification is completed based on finite element analysis. The results show that the designed downward-flipping rear doors ensures reliable sealing in the closed state and can extends the unloading distance in the open state, improving unloading efficiency by about 20%; The structural strength meets design requirements. This design is demonstrated not only to solve the problems of traditional rear doors but also to optimize vehicle axle load and improve transportation efficiency, showing broad application prospects in open-pit mine transportation field. A complete technical solution and theoretical support for the structural optimization of off-road dump trucks cargo box are provided.

Key words: off-road dump trucks; cargo box structure; downward-flipping rear door; kinematic analysis

摘要： 针对现有非公路自卸车货厢存在的物料撒落、后门结构易损及卸料不顺畅等问题，文 章开展了下翻式后门的设计方法研究。文章通过分析非公路自卸车的作业与现有后门结构优 劣，系统阐述下翻后门的自动开启机构设计、铰接点确定、运动过程校核及结构强度验证等 关键设计环节。采用几何建模方法确定旋转点位置，建立运动学方程量化分析开启时机及轨 迹，基于有限元法完成强度仿真验证。结果表明，所设计的下翻后门闭合状态密封可靠，开 启状态可延长卸料距离，提升卸料效率 20%左右；结构强度满足设计要求。该设计不仅解决 了传统后门的问题，而且调整了车辆轴荷，提高了车辆运输效率，在露天矿山运输领域具有 广阔应用前景。文章为非公路自卸车货厢结构优化提供了完整的技术方案与理论支撑。

关键词: 非公路自卸车；货厢结构；下翻后门；运动分析