曲轴圆角感应淬火工艺研究

发布时间：2018-03-13 09:03

本文选题：发动机　切入点：曲轴　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：曲轴是发动机中最重要的零件之一,主要作用是将活塞的往返运动转换成旋转运动,并向外输出全部功率。曲轴工作时所受到的力是相当复杂的,主轴颈、连杆颈和曲柄臂受力情况各不相同,但它们主要承受反复弯曲和扭转负荷,而主轴颈和连杆颈还要承受强烈的摩擦。曲轴的失效形式主要是疲劳引起的断裂和轴颈的磨损,随着大功率发动机的不断推出,长冲程曲轴也随着出现,即增大连杆颈与主轴颈的偏心距,工艺改变引起的问题就是相对薄弱的连杆颈下止点所受到的弯曲扭矩更大,因此提高曲轴圆角疲劳强度是摆在面前的首要任务。我公司在曲轴表面热处理上主要采用曲轴旋转淬火技术,对主轴颈、连杆颈、法兰及止推面进行表面淬火处理,这种工艺已有二十余年的历史;随着科技的进步,人们对发动机的要求也越来越高,大功率的发动机不断更新,曲轴疲劳断裂90%以上发生在连杆颈下止点圆角处,利用Abaqus建模分析后发现连杆颈下止点圆角处所受应力最大。现在多数有名的汽车及发动机生产厂已经开始对曲轴进行圆角强化,这样能极大的提高曲轴的寿命及发动机整机质量。本文通过对调质钢(45钢,42CrMo),非调质钢(S38MnSiV)曲轴材料从原材料的检验,曲轴毛坯的生产加工,圆角淬火感应器的设计制作,淬火工艺试验方案的制定及调整,到成品曲轴淬火硬度、淬火层深测量以及金相检验,最后的曲轴单拐弯曲疲劳试验的进行,对其检测结果进行分析,最终形成合理科学的工艺,使得曲轴圆角淬火工艺成为提高曲轴疲劳强度的有效途径。
[Abstract]:Crankshaft is one of the most important parts in engine. The main function of crankshaft is to convert the reciprocating motion of piston into rotational motion and output the whole power out of the crankshaft. The forces on the connecting rod neck and the crank arm are different, but they are mainly subjected to repeated bending and torsional loads, while the spindle neck and the connecting rod neck are subjected to strong friction. The failure forms of the crankshaft are mainly fatigue induced fracture and wear of the journal. With the continuous introduction of the high-power engine, the long-stroke crankshaft also appears, that is, increasing the eccentric distance between the connecting rod neck and the main journal. The problem caused by the process change is that the relatively weak connecting rod neck has more bending torque. Therefore, it is the most important task to improve the fatigue strength of the crankshaft fillet. In the surface heat treatment of the crankshaft, our company mainly adopts the crankshaft rotation quenching technology, and carries on the surface quenching treatment to the spindle neck, the connecting rod neck, the flange and the thrust surface. With the development of science and technology, people have higher and higher requirements for the engine. The high-power engine is constantly updated, and the fatigue fracture of crankshaft more than 90% occurs at the corner of the bottom of the connecting rod neck. By using Abaqus modeling and analysis, it is found that the stress is the greatest at the corner of the connecting rod neck. Now most famous automobile and engine manufacturers have begun to strengthen the crankshafts. In this way, the life of the crankshaft and the quality of the whole engine can be greatly improved. In this paper, the material of the crankshaft is inspected from the raw materials, the production and processing of the crankshaft blank, the design and manufacture of the round angle quenching inductor by means of quenching and tempering steel 42CrMoO, non-quenched steel S38MnSiV). The formulation and adjustment of quenching process test scheme, including quenching hardness of finished crankshaft, measurement of quenching layer depth and metallographic examination, and finally, analysis of the test results of single bend fatigue test of crankshaft, Finally, a reasonable and scientific process is formed, which makes the crankshaft corner quenching process an effective way to improve the fatigue strength of the crankshaft.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S218.5

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