【作者】 王健；

【导师】 袁兆成；

【作者基本信息】 吉林大学 ， 工程硕士（专业学位）， 2017， 硕士

【摘要】 机体作为发动机的主要部分,就像内燃机的骨架一样,它的内外部安装着内燃机所有的零部件和附件,工作环境恶劣,为了保证内燃机各主要零部件工作可靠、耐久,要求缸体有足够的刚度来保证它们之间精确的相对位置。因此,缸体必须首先满足内燃机各种工况下的刚度要求,保证内燃机不发生机体变形,保证机体重要表面的尺寸、几何形状、相对位置都在安全的公差要求范围内。本文旨在研究493柴油机凸轮轴与轴承发生的异常磨损是否是因为机体刚度不足,导致凸轮轴承过大变形引起的,以决定是否需要重新设计机体、增强刚度。首先,采用有限元分析方法对机体进行了自由模态和约束模态的分析,对十个频率段进行计算得到缸体结构和凸轮轴承的固有频率和振型。其次,根据所提供的发动机设计参数,利用计算流体力学(CFD)软件计算得到缸体冷却水套的整体流场和温度场分布。最后,将缸体冷却水套的温度场作为边界条件导入到有限元软件,施加在缸体上,并将相应的固定约束条件和机械应力载荷一并施加,计算缸体在热负荷和机械应力负荷的耦合状况下的应力状况,重点分析了在该耦合应力状况下机体上凸轮轴承位置是否受力变形。本文通过利用有限元方法对缸体进行了热负荷与机械负荷的耦合分析,得到缸体和凸轮轴承的应变云图,并对缸体进行了刚度分析。再通过与厂家提供的刚度设计要求进行比对分析,最终确定机体的刚度已经达到设计要求,凸轮轴承处没有发生变形,所以,凸轮轴承的变形与缸体的刚度没有关系。需进行其他方面的分析与探究。更多还原

【Abstract】 Engine body as the main part of engine,just like the skeleton of internal combustion engine,which internal and external installation of all internal components and accessories,But the engine body by the heat load and mechanical load in the entire work process,which could have greatly affected the engine work,so in order to ensure that the internal combustion engine main parts and components work durability,reliability and economy of the engine,cylinder body must has enough rigidity to ensure them keep accurate relative position.Therefore,cylinder block must first meet the requirement of internal combustion engine rigidity under various working conditions,maintain the body deformation of internal combustion engine,ensure the body size,geometry,the relative position on the surface of the important within the safety tolerance requirements.This paper aims to study whether the camshaft deformation of the 493 diesel engine is due to the fact that the cylinder stiffness is not satisfied.Firstly,the finite element analysis method is used to analyze the free modal and the constraint modal of the cylinder body,and the natural frequency and vibration modal of the cylinder structure and camshaft bearing are calculated for ten frequency segments;Secondly,according to the engine design parameters provided,using computational fluid dynamics(CFD)software to calculate the cylinder cooling jacket of the whole temperature field distribution;Finally,the temperature field of the cylinder cooling water jacket as a boundary condition introduced into the finite element software,applied to the cylinder body,and the corresponding fixed and mechanical stress loads are applied together to calculate the coupling analysis on the thermal loads and mechanical stress of the state of cylinder body.Under the circumstances,the position of the camshaft bearing on the body under the coupling stress is analyzed emphatically.In this paper,the coupling analysis of the thermal load and the mechanical load is carried out by using the finite element method(FEM)to obtain the strain cloud diagram of the cylinder and the cam bearing,and the stiffness analysis of the cylinder is carried out.Again with the manufacturers to provide the rigidity of the design requirements for comparison analysis,ultimately determine the body’s rigidity has reached the design requirements,the camshaft bearing is not deformed,so the deformation of the camshaft bearing and the cylinder body rigidity is not related.Need to carry out other aspects of the analysis and exploration.更多还原