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...     

大导程滚珠丝杠副螺母的截形计算与加工仿真

根据螺旋面加工原理、齿形啮合原理及回转面砂轮加工螺母工艺建立了相应的数学模型,并推导出砂轮截形的计算公式;采用数值计算方法求解砂轮截形参数,进一步得到修整器靠模板的参数;在此基础上,利用Pro/E软件对大导程滚珠丝杠螺母、砂轮和砂轮修整器进行了实体建模,并对砂轮的修整过程和螺母的加工过程进行了运动仿真,有效地验证了砂轮截形的计算结果。     

大导程滚珠螺母螺旋槽分层包络微细硬车削技术

针对精密加工大导程滚珠螺母螺旋槽的技术难题,提出了分层包络法微细硬车削加工滚珠螺母螺旋槽方法,在平行螺母轴线刀杆上安装刀尖带圆弧的菱形可转位刀片,通过对法向截形等距偏移与坐标变换计算生成包络车削点,实现层层包络车削。以大导程滚珠螺母加工试验为例说明该方法可满足大导程滚珠螺母螺旋槽的加工精度要求,具有较大的技术应用价值。     

滾珠螺母內滾道成型磨削及砂轮截形计算

滚珠丝杠螺母的螺纹滚道是一种空间螺旋曲面。滚道的精加工多采用成型磨削法,加工时需将刀杆上的砂轮在工件内孔一侧磨削。由于工件和砂轮结构的限制,砂轮安装角一般与滚道螺旋升角不一致,即安装角小于滚道螺旋角。为了较精确地磨削出滚道形状,需要根据磨削原理对砂轮进行精确计算。砂轮的形状决定于滚道形状、砂轮安装角度及砂轮直径的最大值。内滚道磨削时,砂轮和滚道的位置关系见图1。本文主要从分析滚珠螺母内滚道的形成原理出发,根据成型磨削的实际过程给出成型砂轮的计算方法,并以实例说明计算方法的运用。     

基于诱导法曲率的齿轮成形磨削干涉分析

如何避免和降低干涉是提高齿轮成形磨削效率和精度的关键技术之一。基于微分几何理论和空间啮合原理,利用无瞬心包络法精确求解磨削一个齿槽的完整砂轮廓形;在对曲面啮合诱导法曲率理论研究基础上,通过计算砂轮曲面和齿轮螺旋面间接触线上任意点诱导发曲率值检验磨削干涉与否,并总结了诱导法曲率随安装参数变化规律和接触线附近干涉区域形成特点,为齿轮成形磨削提出一种如何验证、降低及避免干涉的方法;基于Matlab编写计算程序,以磨削无干涉为限制条件获得砂轮安装角和砂轮半径的取值范围。通过实例计算验证了不合理调整砂轮安装角或砂轮修形将导致磨削干涉,为实际磨削提供了安装参数的合理选取范围,具有实际指导意义。     

金属结合剂砂轮精密成形磨削T15工具钢零件的实验研究

采用金属结合剂金刚石砂轮对T15工具钢进行成形磨削加工实验,获得了形面精度保持性好的成形磨削砂轮,并用其进行长时间磨削加工,得到了满足形面加工精度要求的加工试件.实验表明,采用电火花修形方法对金属结合剂砂轮进行精密修形,可获得满足成形磨削加工要求的砂轮轮廓;在成形磨削过程中,凹槽侧面磨损率始终最大,而砂轮回转面的磨损最为稳定.     

基于切削加工性能的螺杆转子成形砂轮安装参数二次优化设计方法EI北大核心

传统的螺杆转子成形砂轮设计研究主要集中在成形砂轮廓形精度提升方面,成形砂轮的切削加工性能与成形砂轮安装参数之间的耦合关系没有得到足够的关注,导致设计出来的螺杆转子成形砂轮切削加工性能不高,从而致使螺杆转子的成形磨削表面质量差、加工效率低。本文提出了一种新的基于切削加工性能的螺杆转子成形砂轮安装参数二次优化设计方法。首先,基于空间啮合原理设计螺杆转子成形砂轮安装参数优化设计程序,获得不干涉条件下的螺杆转子成形砂轮安装参数范围;其次,对不同安装参数下成形砂轮与螺杆型面的接触特性,以及不同安装参数条件下成形砂轮的轮廓特性、切削加工特性进行系统的分析和研究,获得了螺杆转子成形砂轮安装参数选择策略。以某型号三螺杆泵阳转子为例对该方法进行验证,结果表明,在保证加工质量的前提下,该方法可以显著降低螺杆转子精密磨削成本,具有较好的理论创新性与工程应用价值。     

砂轮的调整精度对滚珠螺母螺纹质量的影响

对滚珠螺母螺纹表面层的精度和质量有高的要求。用有恒半径的半圆廓形砂轮磨削螺纹时,经常在螺纹表面的一侧出现磨削缺陷(烧伤和裂纹)。为了查明它的形成原因,需要研究磨削时砂轮和工件接触迹的情况。某些著作认为砂轮和工件的接触迹是矩形或梯形,即接触线长度恒与砂轮廓形相符合;这样就把螺旋升角的影响忽视了。著作[2]中研究了砂轮相对螺母螺纹表面的调整角度对螺母螺纹廓形精度的影响,并指出了这个角度对磨削情况的影响,即对接触迹形状和尺     

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。     

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。     

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.     

Modeling and numerical simulation for the machining of helical surface profiles on cutting tools

The classical conjugation and envelope method is very accurate and effective for forward and inverse calculations of grinding helical surfaces. However, this method involves complicated mathematics and requires that the profiles be continuous. It can also result in undercutting or interference to the desired surface profiles. In this paper, a new approach is proposed to simulate the grinding process of helical surfaces on cutting tools. The paper begins with the reconstruction of cutter helicoids from sampled points. Using the recovered helical parameters from the sample points, the cross-sectional profile of the cutter surface is derived using a polynomial curve. A numerical method for calculating the profile of the grinding wheel required for the cutter surface profile is then provided. Finally, an optimization method is presented for solving the problem of inverse calculation to determine the helical surface profile for a given grinding wheel profile and setting parameters. The feasibility of the approach is tested by simulation results, which shows that the proposed approach can eliminate undesired tool-work interferences and undercutting.     

Application of self-inhaling internal cooling wheel in vertical surface grinding

There is less research on vertical sculptured grinding technology. Especially in high vertical surface grinding process with the cup abrasive wheel, the thermal damage is prone to happen and undermine the grinding surface integrity. This problem limits to improve the grinding efficiency and the grinding ratio greatly. Through the analysis of vertical surface grinding process and features in depth, this paper revealed the inherent mechanism of higher grinding temperature in the process of vertical sculptured grinding using the cup wheel. Based on the previous research achievements, the grinding experiments on TC4 （Ti-6A1-4V） and GH4169 are carried out utilizing the self-inhaling internal cooling wheel. The experimental results show that the self-inhaling internal cooling wheel can efficiently reduce the grinding surface temperature. Moreover, the inherent mechanism of reducing the grinding temperature using the internal cooling method is revealed. Meanwhile, under the same grinding conditions, the grinding ratio during the experiments on GH4169 using self-inhaling internal cooling method is about 3 times as high as using conventional external cooling method. And the grinding forces can be reduced by about 20%. This research revealed the inherent mechanism of higher grinding temperature in the process of vertical sculptured grinding using the cup wheel, which provides theoretical basis for the design and application of self-inhaling internal cooling wheel. At the same time, an efficient and non-invasive surface grinding method of TC4 and GH4169 is presented.     

全陶瓷球轴承套圈沟道精密磨削用砂轮修整试验

为提高金刚石圆弧砂轮外缘轮廓精度,减少全陶瓷球轴承套圈沟形误差,采用金刚石碟片对树脂基金刚石圆弧砂轮进行修整;对比修整前后砂轮的表面形貌及套圈沟形误差,验证砂轮的修整效果.修整后砂轮表面出现光泽,露出表面的金刚石磨粒明显增多,部分金刚石磨粒破碎,形成新切削刃或脱落,增大容屑空间;修整前沟形误差的平均值为5.823μm,...     

杯形砂轮磨削高硬度球面砂轮磨损的研究

采用分块杯形砂轮磨削高硬度球面,磨削过程中砂轮磨损不仅影响砂轮磨削性能,而且造成工件和砂轮实际接触面积不断产生变化,影响磨削力和磨削质量。为此,基于展成法磨削原理研究砂轮块磨损后的形状变化,分析了分块砂轮的磨损形式,揭示了进给过程中砂轮块磨损形状的变化规律,推导了砂轮磨损量和砂轮工件接触面积的计算公式,分析了砂轮磨损速度的变化趋势及其影响因素,试验最后研究了砂轮磨损量的变化规律,并验证了砂轮磨损量的计算模型。     

Grinding of the inner thread without tilt of the tool spindle

A mathematical model of the grinding process for an inner step thread with an abrasive wheel without tilt of the tool spindle is described. The problem of calculation of a shape of a curvilinear part of the profile of the grinding wheel and simulation of thread processing is solved for the evaluation of a possibility of cutting this thread with the required accuracy using a tool of a certain diameter. Examples of calculation of the process parameters for grinding various types of inner thread are shown.     

螺杆压缩机转子成形砂轮刃形计算

针对给出任意转子型线时转子齿面加工的成形砂轮刃形设计,利用螺杆转子加工过程中转子和砂轮的相对位置关系,通过对转子型线坐标系的旋转变换,建立空间转子坐标系和成形砂轮坐标系之间的几何映射关系;基于啮合原理,建立转子齿面与成形砂轮的接触线方程,并给出解析和离散两种转子型线表达方式的刃形求解方法。在此基础上,根据转子砂轮之间的设计间隙,通过对接触线沿转子齿面法向进行偏置,获得了修整后的砂轮等距齿面刃形,避免了传统修整方法导致的法向齿间间隙不均等问题。加工结果表明,该方法能够满足螺杆转子的加工精度要求,是一种有效的螺杆转子齿面成形砂轮的刃形设计方法,并可推广应用于其他螺旋面成形砂轮或盘形铣刀的刃形设计。     

Modeling,simulation and manufacturing of drill flutes

The designing of twist drill flutes (as well as that of end mills and of some combined tools) cannot be separated from the way they are manufactured. The aim of this paper is to present an intuitive direct method for modelling, simulation and manufacturing of the drill flutes with different shapes using conical grinding wheels with standardized shapes. The mathematical approach is described, which enables us to determine the flute profile in a section perpendicular to its axis as well as the manufacturing parameters. The grinding wheel has an initial position with respect to the cylindrical work piece, which is described using four parameters (Denavit Hartenberg parameters). We have presented algorithms in pseudocode that produce the flute shape and that compute the optimum parameters of the wheel position in the manufacturing process. Subsequently, a software application based on the aforementioned model is able to create visualizations of the flute shape. The analysis of the flute shape has enabled us to understand the influence of the geometrical parameters and the position of the grinding wheel on the resulting product in the grinding process. The order in which these parameters are to be set is also specified. We have built atlases of maps presenting the influence of the geometrical parameters and the position of the grinding wheel in the grinding process upon the shape of the flute. The validity of the method is proven by the agreement of the computed values with the input and output data produced by experiment. The proposed method allows helical flutes to be generated solely by using cylindrical and conical grinding wheels of standard shapes.     

Recognition of diamond grains on surface of fine diamond grinding wheel

The accurate evaluation of grinding wheel surface topography, which is necessary for the investigation of the grinding principle, optimism, modeling, and simulation of a grinding process, significantly depends on the accurate recognition of abrasive grains from the measured wheel surface. A detailed analysis of the grain size distribution characteristics and grain profile wavelength of the fine diamond grinding wheel used for ultra-precision grinding is presented. The requirements of the spatial sampling interval and sampling area for instruments to measure the surface topography of a diamond grinding wheel are discussed. To recognize diamond grains, digital filtering is used to eliminate the high frequency disturbance from the measured 3D digital surface of the grinding wheel, the geometric features of diamond grains are then extracted from the filtered 3D digital surface, and a method based on the grain profile frequency characteristics, diamond grain curvature, and distance between two adjacent diamond grains is proposed. A 3D surface profiler based on scanning white light interferometry is used to measure the 3D surface topography of a #3000 mesh resin bonded diamond grinding wheel, and the diamond grains are then recognized from the 3D digital surface. The experimental result shows that the proposed method is reasonable and effective.