Aiming at the difficulty of control and evaluation of main bearing deformation in the coordination design of the main bearing assembly structure for a high-speed diesel engine, taking MRD (the MRD means the maximum radial deformation of the bearing bush) of the bearing bush as an index to evaluate the out-of-round deformation of the bearing bush was proposed in this paper. The numerical calculation method of the MRD was given and the correctness of the method was experimentally verified. And the influence rules of different design parameters on the MRD were analyzed. On this basis, the coordination multi-objective optimization research of the main bearing assembly structure was carried out, and the optimization results were analyzed based on the influence rules of different design parameters on the reliability indexes. The results show that, when the pre-tightening force of the vertical bolt and the bearing bush interference are 240 kN and 0.17 mm respectively, the MRD reaches the minimum value. If the two values continue to increase, redundant loads can be generated, leading to the increase of the MRD. After optimization, the engine block strength coordination and bearing cap strength coordination had increased by 2.47% and 10.48%, respectively, and the deformation coordination and contact coordination had increased by 46.15% and 14.84%, respectively.

针对高速柴油机主轴承总成结构协调设计中主轴承变形控制与评价难的问题，以轴瓦的MRD（MRD表示轴瓦径向变形的最大值）为提出了一种评价轴瓦不圆变形的指标。给出了MRD的数值计算方法，并通过实验验证了该方法的正确性。并分析了不同设计参数对MRD的影响规律。在此基础上，开展了主轴承总成结构的协调多目标优化研究，根据不同设计参数对可靠性指标的影响规律，对优化结果进行了分析。结果表明，当垂直螺栓预紧力和轴瓦过盈量分别为240 kN和0.17 mm时，MRD达到最小值。如果这两个值继续增加，则会产生冗余负载，导致 MRD 增加。优化后的发动机缸体强度协调和轴承盖强度协调分别提高了2.47%和10.48%，变形协调和接触协调分别提高了46.15%和14.84%。