【作者】 刘星；

【导师】 黄贤振；

【作者基本信息】 东北大学 ， 机械工程（专业学位）， 2019， 硕士

【摘要】 轴承是当今机械设备中的一种举足轻重的零部件,但是目前国内的大部分轴承制造企业主要生产设备仍以传统液压车或者通用数控车床为主,市场上并没有一款专业适合轴承套圈加工的数控车床设备。根据轴承行业的加工需求,设计一款能够解决行业加工痛点的、更高精度、更高效率、适用于轴承行业的专业数控车床对整个轴承行业向高端制造的转型升级具备十分重要的意义。因此,对沈阳机床现有的通用型全机能数控车床i5T3.3(3628s)进行研究,在主轴刚性及冷却排屑系统两个方面作出改进,使其由传统通用型设备转变为符合行业专属需求的专用型设备,用以针对性开拓轴承行业市场,提升产品细分市场占有率。收集i5T3.3数控车床近几年的故障统计数据进行分析,发现在轴承企业的设备故障率在加工精度、表面质量、排屑机三个方面要高于平均水平,然后根据故障原因得出设备在设备刚性、切屑断屑、长卷屑排出这三个问题上需要进行改进。本文对轴承硬车削的加工特点进行分析,通过ANSYS WORKBENCH 16.0软件在硬车削载荷的条件下对i5T3.3数控车床整机进行了有限元静力分析和模态分析,发现机床在加工过程中的主要形变位置是主轴部分,然后通过对形变部位各零件形变量分析,从而找到对形变影响最大的因素是主轴单元。最后,通过理论计算对主轴单元的结构改进升级提供可行的方案,即将主轴单元前端的一个角接触球轴承更换为一个双列圆柱滚子轴承的方式使主轴单元在硬车削参数下的刚性提升了 2.2倍。此外针对轴承钢加工难以断屑及长卷屑难以排出的问题,对冷却系统及排屑系统作出改进升级。采用不同的冷却压力对轴承钢材料进行切削实验,得出在7MPa的高压冷却条件下,轴承钢的切削断屑情况得到明显改善,且刀片的使用寿命得到显著提高。同时,根据长卷状铁屑被链板式排屑机的排出原理,在排屑机整机结构、抬升角度、排屑口形式和运转控制等方面作出改进,使之能够满足轴承钢材料的加工需求。本文对i5T3.3数控车床采用了有限元静力分析和模态分析,为下一步的主轴刚性改进提供了理论依据。根据轴承行业加工中遇到的问题而针对冷却系统和排屑系统作出的改进能够有效提升沈阳机床在细分市场的竞争力,这种分析思路为公司其他产品的改进方向提供了参考。更多还原

【Abstract】 Bearing is one of the most important parts in today’s mechanical equipment,but for most domestic bearing manufacturing enterprises,the main production equipment is still based on traditional hydraulic lathe or general CNC lathe at present.There is no special CNC lathe equipment which is suitable for bearing ring processing in the market.It is of great significance to design a professional CNC lathe according to the processing requirements,which is with higher accuracy,higher efficiency,suitable for the bearing industry,and can solve the processing pain points of the industry,it is quite important for the transformation and upgrading of the whole bearing industry to upmarket manufacturing.Therefore,this paper focuses on the research and improvement of the existing universal full-function CNC lathe i5T3.3(3628s)of SMTCL,and improvement of spindle rigidity and cooling chip removal system,so that it can be transformed from the traditional general-purpose equipment to the special equipment which can meet the industry’s exclusive needs,in order to develop the bearing industry market and enhance the market share of product subdivision.By collecting the statistical data of the failure of i5T3.3 NC lathe in recent years,it is found that the failure rate of equipment in bearing enterprises is higher than the average level in three aspects:processing accuracy,surface quality and chip removal machine.Then according to the causes of the failure,it is concluded that the equipment needs to be improved in three aspects:equipment rigidity,chip breaking and long chip discharge.In this paper,the processing specificity of bearing hard turning is analyzed.The finite element static analysis and modal analysis of the whole machine of i5T3.3 NC lathe are carried out by ANSYS WORKBENCH 16.0 software under the condition of hard turning load.It is found that the main deformation position of the machine tool in the process of processing is the spindle part.Then the static analysis of the spindle box is carried out,the result shows that the most influential factors on the deformation is the spindle unit.Finally,through theoretical calculation,a feasible scheme is provided to upgrade the structure of the spindle unit,that is,replacing an angular contact ball bearing at the front end of the spindle unit with a double row cylindrical roller bearing,which increases the rigidity of the spindle unit by 2.2 times under the hard turning parameters.In addition,the cooling system and chip removal system are improved and upgraded to solve the problems of difficult chip breaking and long scrap removal in bearing steel processing.The cutting experiments of bearing steel were carried out under different cooling pressures.The results show that the cutting chip breakage of bearing steel has been significantly improved and the service life of the blade has been significantly improved under the high-pressure cooling condition of 7MPa.According to the discharging principle of chain-plate scrap removal machine with long rolled iron scraps,the structure,lifting angle,form of chip removal port and operation control of the scrap removal machine are improved to meet the processing requirements of bearing steel materials.In this paper,finite element static analysis and modal analysis are used for the i5T3.3 NC lathe,which provides a theoretical basis for the further improvement of spindle rigidity.According to the problems encountered in the processing of bearing industry,the improvement of cooling system and chip removal system can effectively enhance the competitiveness of SMTCL in the market.This analysis provides a reference for the improvement direction of other products of SMTCL.更多还原