基于摆线旋分原理的齿套倒锥加工方法及刀具设计

针对汽车同步器齿套倒锥加工方法间歇分度、生产效率低等问题,结合平面摆线逼近渐开线的方法,使用了摆线簇逼近渐开线,在此基础之上建立了倒锥旋分加工数学模型,以便得到倒锥加工刀尖切削点轨迹曲线,并提出了一种基于摆线旋分原理的齿套倒锥加工方法。使用了摆线参数控制切削点轨迹曲线的形状来逼近渐开线,以便达到一定的加工精度;使用Matlab进行了仿真实验,证明了齿套倒锥摆线旋分加工方法的可行性。研究结果表明:基于摆线旋分原理的齿套倒锥加工方法及刀具设计理论是正确可行的,所设计完成的倒锥刀具满足同步器齿套厂家对齿套倒锥的加工要求,同时还显著提高了加工效率。     

同步器倒锥齿加工工艺分析

介绍了同步器齿套倒锥齿加工工艺方法,分析了各种工艺方案的利弊,分析发现涨挤法的生产效率、加工精度和加工普遍性都比较高。通过自行制造出的三种涨挤刀,可以用来加工目前所涉及到的所有形式的倒锥齿,解决了缺齿和不等厚齿零件倒锥齿的加工难度和效率。     

潜孔钻机水管接头锥孔加工及检验方法的改进

正我公司生产的某型号潜孔钻机除尘水管过渡接头结构如图1所示。该接头的锥孔B需要与胶管的芯管实现无间隙配合,才能达到较好的密封效果,故此对锥孔B加工精度要求较高。1.存在问题过渡接头原来的加工方法是先加工锥孔B,再依次加工其余各表面。车削锥孔B之前,先将车床小托板调整到所需角度,再进行车削。但是由于过渡接头还有其余4个锥面也需要加工,需要反复调整车床小托板的角度,由此造成工序繁琐、生产效率低下。     

涨挤刀的设计

为防止汽车在行驶中脱档,汽车同步器结合齿套一般都设计有倒锥角,目前比较理想的加工方法是挤压法。加工同步器齿套内结合齿的方法一般称作“涨挤倒锥法”;外结合齿加工方法一般称作“精锻倒锥法”,上述工艺方法都已得到了广泛应用。     

普通插齿机插制倒锥齿

沈阳读者李健同志来信说，因维修汽车变速箱，需要单件或少量加工倒推齿轮。本单位没有加工倒锥齿的专用机床，请告知在普通插齿机上附加工装的加工方法。在汽车变速箱中，广泛使用同步器机构，倒锥齿是将轮齿厚度制成有反向的锥度（见图1），以防齿轮自动脱离结合。此种轮齿可用挤压法形成倒锥，也可用插齿机直接插出倒锥齿。有些型号的插齿机主轴系统（包括立柱）可以倾斜一定角度。图2为加工示意图，加入一楔形势块就可插锥度齿。图1倒锥齿上述挤压机和倒雄插齿机属于专用设备，很难购置，且造价不菲，而通用的插齿机很难改装成图示的倾…     

插倒锥接合齿的工艺计算

图1所示的啮合套倒锥接合齿的加工，既可采取先插直齿再挤锥齿的工艺，也可在工作台轴线偏转可调的插齿机上直接插锥齿。后者比先插直齿再挤锥齿的工效高、加工质量好，是当前加工倒锥接合齿的理想方法。插倒锥齿时，为了调整机床和测量工件以及校核有关设计参数的插齿工艺性，     

同步器齿套倒锥齿加工工艺

随着汽车工业的发展和对汽车使用性能要求的不断提高 ,带同步器的变速箱在汽车工业中得到越来越广泛的应用。为了防止脱档 ,同步器齿套一般都设计成倒锥齿 ,这就给加工制造带来了难度。本文介绍我厂同步器齿套倒锥齿的几种加工方法。同步器齿套的啮合齿一般设计为 2°～ 4°的收缩角 ,因开始设计是用插齿方法 ,在径向插出倒锥来获得收缩角 ,所以通常称作倒锥齿 (见图 1)。图 1　带收缩角的同步器齿套　　一、滚轧法滚轧法是最早用来加工倒锥齿的方法。我厂早在 70年代就采用滚轧法加工“铁牛”拖拉机齿轮的倒锥齿。当时尚没有适合这种工艺方…     

一种新型联动拉紧过渡套

许多重型切削加工用镗铣床的主轴均采用 7:2 4锥度的 6 0号锥孔 ,但在实际加工中 ,根据加工需要 ,有时需使用 7:2 4锥度的 5 0号、4 0号等锥柄刀具。此外 ,直接使用 6 0号锥柄刀具有时会造成一定浪费 ,加之刀具较笨重 ,装卸劳动强度大。因此 ,为了在 6 0号锥孔的主轴上使用其它型号锥柄的刀具 ,就需要采用一种联接辅具———过渡套来实现刀具与接杆的快速更换。利用过渡套可组成一个简易工具系统 ,在普通镗铣床上实现刀具的快速更换 ,完成粗、精镗孔、铣削平面以及钻、铰孔等加工工序。过渡套有多种结构型式。普通过渡套更换刀具时 ,需将整…     

新型数控挤齿机关键结构设计

分析了同步器齿套结构特点及倒锥加工工艺,研制开发了一种基于倒锥齿加工自动对齿装置的新型数控挤齿机,从而解决了倒锥齿加工的自动化问题,大大提高了加工效率.     

新型硬质合金插齿刀制造技术研究

硬质合金插齿刀插削硬齿面(45～65HRC)双联时易崩刃,为此需采用负前角,目前磨制硬质合金插齿刀负前角的方法有锥前刀面法、代圆弧法。锥前刀面法倒角角度不均匀,刃形有理论误差,修整困难;代圆弧法沿刀形倒圆弧,刃形有原理性误差、夹具误差,效率低,柔性差。因此需研制一种新型的负前角加工方法,沿刃形按渐开线倒棱,可以消除原理误差,而且效率高、精度高、柔性好。     

Analysis of electromagnetic force in wire-EDM

This paper clarifies the mechanism of how electromagnetic force applied to the wire electrode in wire electrical discharge machining (wire-EDM) is generated. This electromagnetic force is caused not only by DC component but also by AC components of the discharge current supplied to the wire. We therefore developed and used a two-dimensional finite element method (FEM) program to analyze the electromagnetic field taking into account electromagnetic induction. Assuming that trapezoidal pulse current is supplied to the wire, distributions of the current density and magnetic flux density were analyzed and changes in the electromagnetic force applied to the wire were calculated. Wire movement when the electromagnetic force alone was applied to the wire was also calculated. The calculated wire movement agreed with the measured wire movement when pulse current actually used in WEDM was supplied to the wire, clarifying the mechanism of electromagnetic force generation.     

Fabrication of micro rods by twin-mirroring-wire tangential feed micro electrical discharge grinding

In micro electrical discharge machining (micro-EDM), the precision fabrication of cylindrical micro rods is difficult to achieve with a high processing efficiency. In order to overcome this challenge, this paper proposes a new processing method, which is denoted as twin-mirroring-wire tangential feed micro electrical discharge grinding (TMTF-WEDG). The machining principle, characteristics, and realization of the new method are firstly introduced. Then, the advantages of TMTF-WEDG in terms of machining efficiency and accuracy are demonstrated. The experimental results have shown that the machining efficiency can be increased to more than 70% in comparison with conventional tangential-feed wire electrical discharge grinding. It has also been proved that a minimum removal of material corresponding to a reduction of less than 1 μm in the diameter of a micro rod can be obtained by TMTF-WEDG. This considerably helps in improving the accuracy and repeatability of the machining process. A deviation of less than 1 μm on the diameter of a micro rod has been obtained in a length range of 800 μm. The process repeatability in machining five micro rods has been established to be below 2 μm. The proposed method is therefore of great significance for improving the machining efficiency and ensuring a high precision in the shaping process of cylindrical micro rods.     

A new approach to surface roughness and roundness improvement in wire electrical discharge turning based on statistical analyses

In this paper, the effects and the optimization of machining parameters on surface roughness and roundness in the turning wire electrical discharge machining (TWEDM) process are investigated. In the TWEDM process, a new machining parameter, such as rotational speed, is introduced, which changes the normal machining conditions in conventional wire electrical discharge machining (WEDM). By the Taguchi method, a complete realization of the process parameters and their effects were achieved. The Taguchi method has not been used in TWEDM by other researchers. The surface roughness and roundness were measured to verify the process. In addition, the open-circuit voltage, pulse-off time, open arc voltage, and the inter-electrode gap size, which are replaced by power, time-off, voltage, and servo, respectively, and also wire tension, wire speed, and rotational speed were chosen for evaluation by the Taguchi method. An L₁₈ (2¹?×?3⁷) Taguchi standard orthogonal array was chosen for the design of experiments. The level of importance of the machining parameters on the surface roughness and roundness was determined by using analysis of variance (ANOVA). The optimum machining parameters combination was obtained by using the analysis of signal-to-noise (S/N) ratios. The variation of surface roughness and roundness with machining parameters was mathematically modeled by using the regression analysis method. Finally, experimentation was carried out to identify the effectiveness of the proposed method. The presented model is also verified by a set of verification tests.     

探讨高速走丝电火花线切割加工断丝故障分析及预防

高速走丝电火花线切割加工能够满足我国模具制造以及机械加工的需要,但是在高速走丝电火花线切割加工的过程中容易出现断丝的情况,这对于快速的机械加工以及模具制造而言有着非常大的影响。详述高速走丝电火花线切割加工的原理、高速走丝电火花线切割加工断丝的故障原因以及高速走丝电火花切割加工中断丝故障的解决方法及预防。对于高速走丝电火花线切割加工中断丝的情况要进行分析并预防。     

电火花线切割技术发展动态分析

随着机械行业的飞速发展,对各类电火花线切割机床的需求量不断提高,市场竞争日趋激烈.这种形势刺激了相关厂商加大对相关技术的研究力度,促进了对电火花线切割机床性能及功能的提升,实现了电火花线切割技术的进一步发展.     

Experimental investigation of the real-time micro-control of the WEDM process

The wire electrical discharge machining (WEDM) process has inherent instability due to its high complexity and stochastic characteristics. For more stable and efficient machining, the process must be actively controlled in real time while precisely determining the state of the instantaneous machining process. Feedback information when used in conjunction with an unstable discharge pulse ratio and instantaneous discharge energy can be applied to this micro-control system. This study presents the design and implementation of a system that fulfills these demands. Experimental results demonstrate that the proposed system is capable of simultaneously enhancing the machining stability, machining efficiency, and machining performance. For fine machining, the surface quality was enhanced by approximately 10 % without a loss of machining efficiency. Overall, both the feedrate and the surface roughness could be improved concurrently by more than 5 %.     

慢走丝电火花线切割粗加工仿真系统的开发

为对电火花线切割加工机理有更深刻的认识,了解加工参数对加工精度的影响规律,介绍了一个电火花线切割加工粗加工的仿真系统。仿真系统通过对放电点的探索、工件的去除以及对线电极丝振动的分析,将实际的加工现象形象地再现于计算机上。为证实仿真系统的正确性,将仿真结果与试验结果进行了比较。在试验结果的获取中,为能够得到很难测量的线电极周围的放电间隙和工件形状数据,提出一种新的三维形状测量方法。通过对仿真结果和试验结果的比较,定性地证明了仿真方法的正确性。研究结果表明:改变线电极张力及伺服电压值时,从仿真过程得到的加工形状结果与试验得到的加工形状结果其倾向基本一致;加工缝端部的形状呈凸形还是呈凹形,取决于加工过程中放电爆发力和静电引力的相对大小。     

Multi response optimization of wire EDM operations using robust design of experiments

In this present study a multi response optimization method using Taguchi’s robust design approach is proposed for wire electrical discharge machining (WEDM) operations. Experimentation was planned as per Taguchi’s L16 orthogonal array. Each experiment has been performed under different cutting conditions of pulse on time, wire tension, delay time, wire feed speed, and ignition current intensity. Three responses namely material removal rate, surface roughness, and wire wear ratio have been considered for each experiment. The machining parameters are optimized with the multi response characteristics of the material removal rate, surface roughness, and wire wear ratio. Multi response S/N (MRSN) ratio was applied to measure the performance characteristics deviating from the actual value. Analysis of variance (ANOVA) is employed to identify the level of importance of the machining parameters on the multiple performance characteristics considered. Finally experimental confirmation was carried out to identify the effectiveness of this proposed method. A good improvement was obtained.     

Numerical evaluation of transient thermal loads on a WEDM wire electrode under spatially random multiple discharge conditions with and without clustering of sparks

Thermal load on wire electrode under randomly located multiple discharge condition is the most important consideration for predicting wire breakage in wire electrical discharge machining process. Sometimes the discharges form clusters as observed experimentally by different researchers and may occur because of inadequate evacuation of the debris generated during each discharge. Formation of clusters is more likely in thick work pieces. Clusters are spread randomly along the wire while sparks in each cluster too are random. Such clustering of sparks enhances the intensity of thermal load on the wire. In the present investigation, a one-dimensional explicit finite-difference thermal model is proposed for estimating the transient temperature distribution along the length of the wire under the conditions of randomly located spatial sparks with and without the formation of clusters. While each of the electric discharges is simulated as a volumetric heat source present within the wire over the discharge channel width, which in turn is calculated from the available literature, the successive sparks and cluster of sparks are located on the wire by means of a random function. The predicted values of maximum wire temperatures indicate the degree of wire rupture risk, which has been found to be different for short and long elapsed times. Accordingly, random pulse and clusters models are suggested for predicting thermal loads while machining thin or thick work pieces, respectively. The effects of work-piece height, power input, pulse frequency, duty factor, wire velocity, wire diameter, and the convective heat transfer coefficient have been reported. The one-dimensional thermal models may be used for setting rules of selection for an expert system for the safe operating conditions of wire electro-discharge machining.     

超声电火花复合加工速度工艺试验研究

电火花加工的最大缺点是加工速度低，为了解决这个问题，人们进行了各种试验研究。其中超声电火花复合在加工小孔中可一定程度地提高加工速度，但就其作用机理和适用范围仍存在许多争论。本次试验在D703F高速电火花小孔加工机床上附加陶瓷换能器和变幅杆，通过夹紧装置将变幅杆与工具电极相连，实现电极超声振动的电火花小孔加工。在不同的电参数（电流强度和脉冲宽度）和电极参数（电极直径）下，进行了2种加工方法下的加工速度对比试验。找到了在加工小孔时，是否采用超声电火花复合加工工艺的分界点，对其增加加工速度的现象提出了新的解释。