装配式凸轮轴连接工艺的研究

发布时间：2018-04-09 15:44

本文选题：装配式凸轮轴　切入点：连接工艺　出处：《吉林大学》2016年硕士论文

【摘要】：装配式凸轮轴(也叫组合式凸轮轴),是近几年在发动机降重减排战略中出现的新型凸轮轴,与传统凸轮轴最大的区别在于:传统式凸轮轴是一个单独的零件,而装配式凸轮轴是由多个小零件组成的总成,这些小零件有凸轮、轴颈、头端、尾端、信号轮、泵凸轮等,装配式凸轮轴的形式也有很多种,比如,有的凸轮轴轴颈尺寸设计的很大,这样的凸轮轴轴颈就要作为一个单独的零件和凸轮一起都压装到轴体上,有的凸轮轴轴颈尺寸设计的很小,只需将凸轮压装到轴体上,然后在轴体上加工出轴颈;还有一种情况:凸轮轴的大部分凸轮铸造在轴体上,有特殊要求的凸轮(通常是对压应力有特殊要求的凸轮)压装到轴体上,这些都属于装配式凸轮轴的范畴,通常,装配式凸轮轴定义为:凸轮轴的旋转部件与管件采用某种连接技术进行连接的凸轮轴。凸轮轴是发动机配气机构的关键零部件,凸轮轴是一根细长轴,在轴体上有若干个凸轮、轴颈、信号盘、齿轮等,安装在缸盖的气门室里,凸轮轴的失效形式主要是凸轮表面出现点蚀、划伤、凸轮相位角变化(只有装配式凸轮轴会出现)及快速磨损,如果凸轮出现这些失效形式,会使气门开闭规律失常,会出现进气不足、排气不净等一系列的问题,影响发动机正常运转,因此,凸轮轴应具有足够大的强度和韧性,凸轮与轴体之间要具有足够的连接强度。传统工艺制造的凸轮轴制造成本高、生产效率低、能源消耗大、工人劳动强度高等缺点已经追不上凸轮轴设计的发展速度,尤其是近几年VVL(可变气门升程)技术的成熟,凸轮的厚度变窄,外形复杂程度增加,对凸轮轴的整体结构几乎重新定义,传统工艺已经无法满足,装配式凸轮轴的变革是一个必然趋势,装配式凸轮轴采用新颖的构思,将轴凸轮与轴体分开准备,最后采用组装工艺结合为一体,在降重、材料,尤其是机械加工成本,无论是能源成本、人工成本还是设备成本等方面都有显著的优势。本文主要研究了国内现在使用的几种装配式凸轮轴的制造工艺,客观的阐述这些制造工艺各自的优缺点以及在生产中存在的问题与风险;在制造工艺的阐述中,也对目前国内外发动机凸轮轴的形式以及结构进行了认识性的分析;最后,结合一汽轿车CA3GA发动机凸轮轴对装配式凸轮轴的热压工艺进行了详细的分析试验。
[Abstract]:Assembly camshaft (also known as combined camshaft) is a new type of camshaft that has appeared in engine weight reduction and emission reduction strategy in recent years. The biggest difference from traditional camshaft is that traditional camshaft is a separate part.The assembly camshaft is composed of several small parts, such as cam, journal, head end, tail end, signal wheel, pump cam, etc. There are many kinds of assembly camshaft, for example,Some camshaft necks are designed to be very large in size, and such camshaft necks are pressed onto the shaft body as a separate part and cams, and some camshaft necks are designed to be small enough to press the camshaft onto the shaft body.The journal is then machined on the shaft; in another case, most cams of the camshaft are cast on the shaft, and the cam with special requirements (usually one that has a special requirement for compressive stress) is pressed onto the shaft.These all belong to the category of assembly camshaft, usually, assembly camshaft is defined as camshaft which is connected by some connection technology between camshaft rotating parts and pipe fittings.Camshaft is the key part of engine valve mechanism, camshaft is a slender shaft, there are a number of cams, journal, signal disk, gear, etc., which are installed in the valve chamber of cylinder head.The failure forms of camshaft are mainly pitting, scratching on the surface of cam, change of cam phase angle (only assembled camshaft will appear) and rapid wear. If the cam appears these failure forms, the opening and closing of valve will be disturbed.There will be a series of problems, such as air intake insufficiency and exhaust impurity, which will affect the normal operation of the engine. Therefore, the camshaft should have enough strength and toughness and sufficient connection strength between the cam and shaft body.The manufacturing cost of camshaft manufactured by traditional technology is high, the production efficiency is low, the energy consumption is large, the labor intensity of workers is high and so on. The development speed of camshaft design has been unable to catch up, especially the VVLV (variable valve lift) technology has matured in recent years.The thickness of cam becomes narrower, the shape complexity increases, the whole structure of camshaft is almost redefined, the traditional technology can not be satisfied, the change of assembly camshaft is an inevitable trend, and the assembly camshaft adopts novel conception.The shaft cam is prepared separately from the shaft body, and the assembly process is used to combine it. It has obvious advantages in weight reduction, material cost, especially machining cost, whether energy cost, labor cost or equipment cost, etc.This paper mainly studies the manufacturing technology of several kinds of assembly camshaft used in our country, and objectively expounds the advantages and disadvantages of these manufacturing processes and the problems and risks existing in the production.The form and structure of camshaft at home and abroad are also analyzed. Finally, combined with FAW CA3GA engine camshaft, the hot pressing technology of assembled camshaft is analyzed and tested in detail.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U464.134.1

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