﻿ 船用低速柴油机主轴承盖预紧实验研究
 舰船科学技术  2017, Vol. 39 Issue (9): 96-100 PDF

Experimental research on a marine low speed diesel engine of main bearing cap tension
WANG Kui, ZHANG Qiong-yu, WU An-min, LIU Xu, TU Dan-hong
China Shipbuilding Power Engineering Institute Co., Ltd. Shanghai 200129, China
Abstract: During the design process of main bearing cap for a low-speed diesel engine, the tilt main bearing cap bolts are used, the purpose is that: the horizontal force generated by the preload of the bolts, makes the bearing cap open on both sides, then the automatic center location of the cap is achieved. In the tensioning and assemble experiment, it was verified that the automatic location of the cap can be achieved via main bearing cap bolts tensioning. Then the influence law of the tensioning force on slip displacement of the cap was studied by finite element method, and the friction coefficient between the contact surfaces of bearing cap and the bearing block was obtained, which validated and supplied the experiment.
Key words: marine low speed diesel engine     main bearing cap     tensioning deformation     location
0 引　言

1 主轴承盖张紧实验

 图 1 主轴承盖张紧变形实验示意图 Fig. 1 Schematic diagram of main bearing cap deformation experiment

 图 2 张紧变形实验 Fig. 2 Tensioning deformation experiment

 图 3 张紧实验结果 Fig. 3 Tensioning experiment result

 图 4 主轴承盖安装实验示意图 Fig. 4 Schematic diagram of main bearing cap assembly experiment

 图 5 安装实验 Fig. 5 Assembly experiment
2 有限元模型

 图 6 有限元模型 Fig. 6 Finite element model

 $F = P \times S \times 95\% {\text{。}}$

3 结果分析与讨论 3.1 有限元结果验证 3.1.1 张紧实验结果验证

 图 7 主轴承盖装配工况 X 方向位移结果 Fig. 7 The displacement result of the main bearing cap in X direction in tensioning loadcase

 图 8 有限元计算结果与实验结果对比 Fig. 8 The comparison of finite element calculation results with experiment
3.1.2 安装实验结果验证

 图 9 主轴承盖装配工况 X 方向位移结果 Fig. 9 The displacement result of the main bearing cap in X direction in assembly loadcase

 图 10 单侧位移量与摩擦系数的关系 Fig. 10 The relation of one side displacement with friction coefficient
3.2 主轴承盖螺栓杆身应力分析

 图 11 螺栓杆身某截面应力分布 Fig. 11 The stress distribution of the bolt body section

 图 12 螺栓杆身应力差与泵压的关系 Fig. 12 The relation of one side displacement with friction coefficient

4 结　语

1）接触面摩擦系数对轴承盖的变形影响很大，为了保证螺栓张紧时轴承盖的侧面的滑移量，在轴承座和轴承盖的装配过程中需预先在接触面上涂抹润滑油。

2）采用斜的主轴承盖螺栓，会导致杆身出现较大的应力差值，会发生较大的弯曲变形，在设计时可以根据螺栓杆身截面等效应力差作为螺栓弯曲应力的评价标准。

3）本文通过实验与有限元分析相结合为主轴承盖和主轴承座之间摩擦系数的获得提供了一种有效的计算方法。

4）有限元分析和实验研究起到了很好的互相补充的作用，通过两者结合能找出各自容易忽略和难以发现的问题。

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