高功率密度液压集成块的金属增材制造关键技术研究

Strengthening the advantage of high power density is the key factor to improve competitiveness and widen application of hydraulic transmission. According to the two research hotspots of hydraulic components and additive manufacturing, the selective laser melting technology is innovatively adopted to realize the light-weight and energy-saving design of hydraulic manifold block in this research. The key technologies on the three dimensional modeling, processing and heat dissipation design are studied, in order to develop the design method of high power density hydraulic manifold block utilizing additive manufacturing. To solve the combinatorial optimization challenge of complex spatial flow passages, the backtracking strategy is employed to optimize the multi-objectives with different priorities. The flow passages with irregular section and inner supporting structure are proposed to solve the collapse and warping problems of the suspension surface, and the energy consumption characteristics are discussed. The relationship between the cleaning efficiency of the loose metal powder and the flushing parameters and the flow channel structure parameters, and evolution mechanism of local low density porosity under high-frequency fluctuating pressure are studied, in order to improve the surface quality of the complex spatial flow passages. According to the distribution characteristics of heat transfer coefficient of the hydraulic manifold block, the design method of enlarging heat radiation area and adding circulating cooling channels are discussed in details to improve the heat dissipation characteristics of the hydraulic manifold block. By the multidisciplinary of hydraulic transmission and additive manufacturing, a new solution for the design of high power density hydraulic drive system is provided, striving to realize the practical application in the areas such as robot.

强化功率密度优势是提高液压传动竞争力和扩大应用领域的关键。结合液压基础件和增材制造两个研究热点，本项目拟采用选区激光熔融金属增材制造实现液压集成块的轻量化和节能化设计。探讨三维建模方法、加工工艺及散热设计等关键技术，建立高功率密度增材制造液压集成块设计方法。针对空间复杂流道的组合优化难题，通过可回溯设计实现不同优先等级设计目标的智能优化，重点探索采用带内支撑结构的异形截面流道解决悬垂面坍塌和翘曲问题的可行性及其能耗特性；探索流道表面松散金属粉末清理效率与冲蚀参数和结构参数映射关系，揭示局部低致密度孔隙在高频脉动压力冲刷下的渐进剥落演化机理，改善空间复杂流道内壁表面质量。结合液压集成块对流换热系数分布特点，研究增大散热表面积和增设循环冷却流道的正向设计方法，提高液压集成块散热特性。通过液压传动和增材制造的学科交叉，为高功率密度液压传动系统设计提供新解决思路，实现在机器人等领域的工程应用。

液压系统具有驱动力大、易于实现安全保护等优势，在工程领域和高端制造工业中具有广泛应用。强化功率密度优势是提高液压传动竞争力和扩大应用领域的关键，本项目以金属增材制造为切入点，围绕液压集成块的轻量化和节能化设计需求，取得了如下研究进展：.1）建立了集成块内部流道压损的仿真模型，明确了集成块内部压损形成机理；突破传统加工技术的工艺限制，探究了不同平滑流道组合下的压力损失映射规律，实现了三维空间内任意流向、任意曲率的流道加工，实现了40.8%的压损降低，克服了传统加工液压集成块流道局部压损高的缺点；.2）针对空间复杂流道的组合优化难题，实现了不同优先等级的成型工艺优化控制，探索了异形截面流道对成型精度的作用规律和工艺参数对表面成型质量的映射关系，揭示了粉末在局部高能量密度激光作用下的熔化机理，改善了液压集成块复杂空间流道的内壁表面质量；.3）围绕液压集成块散热性能提升，建立了共轭传热仿真模型，探究了液压集成块对流换热系数分布特点；结合液压集成块轻量化设计需求，提出了增大散热表面积和增设循环冷却流道的正向拓扑设计方法，建立了具有主动/被动散热能力的优化模型，在减重一半以上的情况下，提高了液压集成块散热特性，有助于机器人和航空航天等领域集成式液压系统的应用。.本项目发表论文发表学术论文13篇，其中SCI文章9篇，EI论文10篇。其他论文3篇，1篇论文获2019年国际流体动力学会最佳论文奖(2019 Global Fluid Power Society Best Paper)。申请发明专利4项，培养博士研究生3名、硕士研究生3名，项目负责人获2019年国家优秀青年基金—“高功率密度液压驱动”。