大导程滚珠螺母内滚道接触区磨削分析

针对成形磨削大导程滚珠螺母滚道时磨杆与螺母干涉碰撞的技术问题,基于螺旋面加工原理对砂轮计算截形坏点及滚道廓形误差进行详细分析.在调整安装参数无法满足滚道完整包络成形的前提下,提出了以滚道接触区廓形最大化为目标的精密磨削工艺及相应的砂轮选型与安装参数优化方法.以4040型号大导程滚珠螺母磨削试验为例,验证了该方法可满足大...     

大导程滚珠螺母磨削砂轮廓形精确设计和干涉消除

针对在加工大导程滚珠螺母时,可能会出现砂轮磨杆与螺母端面发生干涉的问题,从滚珠螺母磨削加工的基本方法出发,依据砂轮回转面与被加工螺母内滚道面包络的接触线是一条空间曲线的原理,建立任意安装角度下砂轮回转曲面的计算模型,并将此计算模型用于解决大导程滚珠螺母加工干涉问题.提出在保证加工时不发生干涉的前提下,选取砂轮最佳安装角和中心间距参数的方法以及在此参数下砂轮廓形的拟合优化方法.该方法计算简单、可以随时根据安装角和中心间距参数值对砂轮廓形进行修整,以保证磨削精度.以某型号大导程滚珠螺母为例,完成在保证不发生干涉的情况下相关工艺参数的选择以及砂轮廓形的优化设计,对结果进行误差分析,验证了方法的有效性.     

高速硬体旋风铣削在滚珠螺母滚道加工中的应用

滚珠螺母滚道的加工难度随着它的螺旋角的增大而增加，至今还没有可以达到较好的滚道形状几何精度的高速高效的加工方法。近年出现了一种高效高精度加工滚珠螺母的新方法，称之为高速硬体内螺纹旋风铣削，这种方法在大导程滚珠螺母滚道的加工上更能显示其独特的优越性。     

多头内圆弧螺旋槽数控车削刀具的制作

针对大导程圆弧螺旋槽在数控车削加工中无标准成形刀具现状,通过设计可调式分度装置,利用线切割锥度加工功能,解决了圆弧螺旋槽大导程刀具复合后角精密切割,实现了三头内圆弧螺旋槽数控刀具高精度标准化制作。     

大导程圆弧滚道的拉削加工

本文通过对大导程滚珠丝杠副螺母滚道的特点分析．提出一种成形拉削大升角小直径圆弧滚道的加工方法．可使大导程滚珠丝杠副的制造难度大幅度降低。     

大模数阿基米德双导程蜗杆的数控加工

通过综合使用分层切削法和中左右切削法,有效解决了车削大模数蜗杆容易“啃刀”的难题,同时在齿面两侧精车时按不同导程车削达到双导程的要求.但这样的工艺路线也带来编程难度加大的矛盾,通过巧妙利用宏程序的循环指令和循环嵌套,配合螺纹加工循环指令,很好地解决了编程的矛盾,这种方法适用于任何大模数的螺旋槽加工.     

一种加工大导程螺母内滚道方法的研究

针对大导程滚珠丝杠副螺母内滚道难磨削技术缺陷,提出了一种冷挤压加工大导程螺母内滚道的成形方法。同时,基于切削—挤压复合理论学习基础上设计了一种新型加工螺母内滚道刀具。基于对挤压刀具设计,本文在有限元分析软件DEFORM-3D中进行了仿真加工分析。     

精密超大导程滚珠丝杠

如图所示,为日本NSK公司开发的U系列(精密超大导程)滚珠丝杠,钢珠与丝杠与螺母的槽中循环滚动,螺母两端设有循环零件(端盖),与螺母构成循环通道。U系列丝杠因导程特别大(为标准丝杠的4～8     

滚珠丝杠螺母内滚道位置度的测量

针对目前加工滚珠丝杠螺母时,回珠器孔与螺旋槽的相对位置无法现场检测的问题,提出了将直接测量转变为间接测量地方法,设计了一种新型的滚珠丝杠螺母内滚道位置度测量方法,构建了一套滚珠丝杠螺母内滚道位置度测量系统。利用该方法对滚珠丝杠螺母内滚道进行了位置度测量,并与理论值进行了比较。结果表明,该方法具有较高的测量精度及可靠性。研究结果可为回珠器与螺母内滚道的加工位置精度的测量奠定基础。     

小直径、大导程非标准内螺纹车削方法的探讨

[1]问题提出 　　小直径、大导程内螺纹的车削加工比较困难,其一是直径小,刀杆细,刚性差;其二是导程大,螺旋升角必大;其三是导程大、头数多,分头困难。如果是单件、少量生产,一般不采用分头器分头。 　　如图 1所示零件的内螺纹,孔径 20 ,导程 160、 4头、非标牙型。 [2]内螺纹加工分析 　　(1)螺旋升角λ tanλ =L/π d2=160/(3.14× 23)=2.2154　　λ =65° 42′ 26″ 　　螺旋升角特别大,对纵向进给的刀具将产生很大影响。 　　(2)螺纹法向槽较宽且精度较高 螺纹刀头主 刀刃若能与螺旋升角方向相垂直,可便于控制刀头刃磨…     

Grinding of high-lead and gothic-arc profile ball-nuts with free quill-inclination

A method for gothic-arc ball-nut grinding is presented. The gothic-arc is a combined curve of two arcs with the same radius and shifted centers. Generally, gothic-arcs are manufactured by form grinding; the grinding wheel is formed into the gothic-arc and is tilted at the lead angle of the thread. In ball-nut grinding, which is internal grinding, interference between quill (wheel shaft) and internal surface of a workpiece limits the length of the ball-nut. In the presented method, the quill is tilted independently of the lead angle so as not to contact the internal surface of the workpiece. Instead, the wheel is formed into an optimum profile with which the nut obtains a gothic-arc profile. The procedure of finding the optimum wheel profile is presented. Grinding simulation showed that the gothic-arc thread is obtained accurately by the method, though a part of the thread surface is not a perfect gothic-arc. This method allows the use of large-diameter wheels to manufacture high-lead ball-nuts.     

Experimental and numerical study of the load distribution in a ball-screw system

In this work, load distribution on ball-screw systems (BSS) is determined by experimental techniques. Two optical techniques are used: photoelasticity for stress-field measurement and the mark-tracking method for displacement-field determination. In parallel to the experimental study, finite element method (FEM) and analytical solutions are used to calculate the loads applied on each ball of the BSS. Experimental results are used to validate the choice of boundary conditions and contact conditions between ball-screw and ball-nut in the FEM solution. The validation criterion is the correspondence between numerical and experimental fringes representing the differences of principal stresses. In addition to the study of load distribution, this paper presents the influence of the angle of contact direction on the stress distribution in BSS.     

包络法加工超环面行星蜗杆传动定子的研究

本文对超环面行星蜗杆传动的原理及定子齿形的形成过程进行了分析，并运用啮合理论的包络法得出了超环面行星蜗杆传动的定子齿廓方程和齿形。以此为依据，对超环面行星蜗杆传动定子的包络加工方法及工装设计进行了研究，最后在滚齿机上制造出了这种传动的定子。     

X-ray diffraction investigation of white layer development in hard-turned surfaces

Hard turning process is widely used for finishing the hardened surfaces of machine parts exposed to high load. Such parts can be gears, bearings, or short shafts. As in each machining process, hard turning may change the properties of the surface layer. In this research work, we deal with material structure changes developing in the bore of gears made of a material of 20MnCr5. Microscope images show that the structure of the material is altered on the surface of the bores due to the turning process under different conditions. In certain cases, a certain layer that cannot be etched develops, called a white layer. Surface layer modification may take place using different technological data. In this paper, we will prove that proper selection of these technological data (cutting speed, depth of cut, feed rate) may eliminate the formation of a white layer or may decrease its thickness. The fine structure of this surface layer was investigated using the X-ray diffraction method, whilst the thickness of the layer was measured by a computer image analysis method. In this paper, the different conditions for the development of the white layer are described, its composition and some of its properties are determined, and the relationship between technological data and the thickness of the white layer is investigated.     

滚动螺旋换向机构

在左右螺旋线交叉的螺旋换向机构中采用双旋转销交替承载 ,交替过“沟”及浮动销升距补偿方案 ,把该机构中的滑动摩擦传动转变为滚动摩擦传动 ,提高了该机构的效率、速度和寿命 ,扩大了该机构的使用范围。     

基于凸多边形的直线度误差的评定

通过对两平行直线包容测量数据点的分析,得到了两平行直线具有最小距离时必经过凸多边形的3个顶点的条件。根据上述条件,提出了基于凸多边形的直线度误差评定的方法,该方法满足最小包容区域。为求解直线度误差,采用矢量积构造凸多边形。通过实例验证了该方法的正确性和有效性。     

Wear mechanism of the loose layer on the rake face of a new cemented carbide micro groove turning tool

The loose layer can appear on the rake face of a turning tool under certain cutting conditions and have an important influence on the rake face wear. In this paper, wear morphology and wear mechanism of loose layer on the rake face of the original turning tool and the new cemented carbide micro groove turning tool developed independently during the cutting process are studied, by the combination of theoretical analysis and cutting test. And the relationships between the diffusion wear and the adhesive wear of the loose layer on the rake face of the new micro groove turning tool are further analyzed and revealed. The research results show that the loose layer on the rake face of two turning tools is caused by the diffusion wear, which is formed by the brittleness-weakening of tool material in the region resulting from elements diffusion. Meanwhile, the wear degree of the rake face of tools is aggravated by the mutual promotion of diffusion wear and adhesive wear. In the normal wear stage, the degree of looseness and brittleness of the rake face of the original turning tool is greater than the one of the micro groove turning tool. In the severe wear stage, cobalt elements in the rake face of the two turning tools are dissolved and diffused in varying degrees, which further aggravates the brittle-weakening of materials in the region. But the degree of loose brittleness of the rake face of the original turning tool is still greater than the one of the micro groove turning tool. It can be concluded that the micro groove on the rake face of the new turning tool can improve the rake face wear to a certain extent.     

单螺杆泵定子内螺旋曲面包络镗削技术研究

结合单螺杆泵定子衬套的特殊结构,提出了定子内螺旋曲面加工的新方法即无瞬心包络镗削方法,该方法以螺杆-衬套副的运动原理为依据,以螺杆无瞬心包络铣削加工方法为理论实践基础,利用数控机床实现定子内螺旋曲面廓形的镗削加工。还分析了螺杆在衬套中的运动规律,阐述了无瞬心包络镗削加工技术的基本原理,并论证了该技术实现的可行性。     

用于磨削面齿轮的蜗杆砂轮修整方法研究

为了实现面齿轮磨齿加工,采用包络原理对面齿轮磨削蜗杆砂轮齿形进行设计,并对蜗杆砂轮的修整方法进行研究.建立了蜗杆砂轮齿面的包络坐标系;给出了蜗杆砂轮产形面方程;推导了蜗杆砂轮齿廓的曲面方程,利用Matlab软件对蜗杆砂轮齿廓进行了仿真,根据面齿轮磨削蜗杆砂轮的齿面生成原理,给出了修整工具的齿廓形状、齿宽限制以及修整工具...