中信重工制成国内最大模数硬质合金滚刀

目前国内模数最大（M36）、用于精加工大型、特大型齿轮的硬质合金滚刀4月在中信重工制造完成。经各方面的精密检测，该滚刀完全达到设计要求。     

刃磨螺旋齿蜗轮滾刀靠模型面的计算(上)

《机械工艺师》83年第3期“刃磨滚刀砂轮曲线的修整”一文,介绍了在M6420B及3A642滚刀磨床上磨削螺旋齿滚刀前刃面用的靠模装置及靠模型面的设计方法。我们在制造模数M8、M16两种AA级螺旋齿蜗轮滚刀中仿制了该装置,结构稍有改变。该装置充分利用了原机床修整器机构,具有结构简单,使用方便,制造容易等优点。但该文提供的靠模型面设计方法需要改进,因为用该文介绍的方法设计     

采用跃进滚刀的体会

跃进滚刀是根据西道连柯所提出的进步滚刀,经过我厂在实际使用中,结合正前角滚刀结构加以修改后,定名为跃进滚刀(图1)。这种滚刀的设计与计算已有许多文章介绍过,因此不再重述,现仅据我厂的使用作会作个简单介绍。 经本厂试验证明: 1.采用跃进滚刀的效果是良好的,能使生产效率提高四倍以上 2:采用跃进滚刀的首要条件是需有刚性较好的轨床。如在532 机床上试验时,振动较大,使加工物表面光洁度不佳,但用532-7及5330机床时,则刚性足够。 .3.汾力D工小模袭齿轮(模发小于3)采用趺玟汶刀的效果并不易落,国力儿刀树的负荷来看,用省通度刀走3—4公…     

我国汽车齿轮加工刀具的水平

我国汽车齿轮刀具和拉削刀具与日本、西德齿轮刀具和拉削刀具,在设计和结构上有不小的差距,现分述如下: 一、齿轮滚刀日本的滚刀大部分是圆磨法镶片滚刀,滚刀刀片的材料是钴基高速钢,如SKH55、KCM4、HS53M、M35等。以2头3头为主。由于刀片毛坯尺寸小,锻造比可以很大,因此内部金属组织均匀,淬透性好,直到心部都可见到均匀的热处理组织。其次,圆磨镶片滚刀在螺纹磨床上磨出刀齿,刀齿后面均能磨出,所以有效齿背宽大,只要刀齿强度允许,可以尽量刃磨,因此它的有效刃磨长度几乎比整体铲齿滚刀高一倍。另外,圆磨镶片滚刀刀齿采用大     

刃磨滚刀砂轮曲线的修整

在 M6420B 及3A642滚刀磨上磨削螺旋滚刀前刀面时,由于螺旋干涉,用直面砂轮磨削会在前刃面上形成中凸现象。滚刀螺旋角越大,凸出量越大,如图1所示。要使滚刀前刃面保持平直,砂轮必须按某种曲线修整。而这种滚刀磨没有修肇砂轮曲线的装置。     

加长小直径剃前滚刀

近年来，欧洲和日本在汽车齿轮生产中越来越多地采用加长、小直径、多头数、PVD涂层的剃前齿轮滚刀。据资料介绍，这种滚刀的滚切效率和刀具寿命较标准滚刀均有大幅度提高。我厂为上海汽车齿轮厂试制的加长小直径剃前滚刀经现场切削试验也取得了很好的效果。通过实践，加长小直径滚刀优于传统的大直径滚刀的观念正逐步在齿轮行业（首先是汽车齿轮行业）被认识和接受。1．加长小直径滚刀的优点（1）由于切削长度较标准滚刀增加2～3倍，增加了串刀次数，使滚刀寿命成倍增加；（2）由于其外径较装配式圆磨滚刀减小30％，缩短了滚齿加工中的进…     

硬质合金滚刀的钎焊试验

近年用硬质合金滚刀进行硬齿面的滚齿加工有了很大成效。M2-40的硬质合金滚刀为钎焊式结构,可加工淬硬的直齿、斜齿和圆柱齿轮,纠正齿轮预加工时的各项误差,在精密、高精密的齿轮加工中应用很广泛。但在使用过程中存在掉片、裂片、断齿等现象。对钎焊式硬质合金滚刀不同的钎焊工艺方法、钎料等进行试验对比,并采取措施,可提高硬质合金滚刀的钎焊质量,有效降低钎焊成本。     

用钴高速钢刀具滚铣中硬齿面花键

本文介绍了40CrMnMo合金钢经调质处理至HRC40～45后的切齿工艺.由试验得出,在V=25m/min,s=1.25mm/r的条件下,采用正前角M42涂层滚刀(前角为10°)可获得最佳的切削效果.该项成果不仅解决了汽车后桥半轴花键的加工与装配质量问题,而且扩大了经TiN涂层M42钴高速钢的应用范围。     

直槽小模数滚刀的制造工艺

<正> 难加工和经淬火的钢和合金以及石墨青铜的圆柱形小模数齿轮(原始齿廓按9587-68规定)系采用BK10M(3882—74)和BK15M(技术条件48—19—24—72)硬质合金制成的A、B、C 三种精度等级的滚刀加工。A、B 级滚刀的尺寸极限偏差符合10331—63规定,C 级滚刀符合2—035—391—75技术条件规定。其余的技术要求符合2—035—392—75技术条件规定。     

多线滚刀铣削变位齿轮时的磨损

在变位齿轮的铣齿加工中,特别是在用多线滚刀高速铣削变位齿轮时,铣齿方式直接影响着滚刀的磨损和寿命,下面是一组多线滚刀以不同的铣齿方式铣削变位齿轮时滚刀的磨损状况比较图表。 (1)外径为110mm、3线右旋、N(刀槽数)=12、材质M34 TiN(氮化钛)的涂层滚刀,以f(进给量)=3mm/r、(铣削速度)v=40和70m/min,采用顺铣法铣     

涂层滚刀加工喷焊齿轮的试验研究

本文研究了用涂层滚刀加工镍基喷焊齿轮的试验结果。结果表明涂层滚刀的耐磨性和抗粘结能力有所提高,但刀具的磨损,特别是边界犁沟形式的磨损比较严重,复会涂层滚刀的磨损相对要小些。     

基于心形孔的Hy-Vo齿形链的啮合分析及其设计方法

基于Hy-Vo齿形链与链轮刚柔传动的啮合原理及其链轮滚刀与链轮的滚切原理,以Hy-Vo齿形链工作链板齿形视作滚刀法向齿形的设计理念,建立基于心形孔的Hy-Vo齿形链—链轮—刀具齿条的啮合设计体系;根据Hy-Vo齿形链链轮与刀具齿条的共轭啮合条件,提出当工作链板齿形角不等于渐开线齿形链轮压力角时的参数变换的啮合设计方法,并进行实例设计计算。通过171 h台架磨损试验,研究该新型Hy-Vo齿形链的耐磨特性,由于该新型Hy-Vo齿形链链板孔形状类似心形,组成异型销轴截面的各段圆弧均为外凸曲线,因而异型销轴与链板心形孔外侧曲线定位时,比圆形基准孔和长腰形基准孔更稳定,接触面积更大,该新型Hy-Vo齿形链具有较高的耐磨性,试验研究表明,这种新的啮合设计体系和设计方法是科学的,是切实可行的。     

齿轮高速干切滚刀寿命预估模型与优化方法

由于齿轮高速干式滚切工艺切削速度高且缺少切削油的冷却润滑,为满足高速干切滚刀的抗磨损、耐高温等性能要求,高速干切滚刀基体材料和涂层的制备工艺均较为复杂,且价格昂贵,因而需要优化高速干切工艺以延长高速干切滚刀使用寿命,进而降低工件制造成本,提高效益。结合生产实践和理论分析,研究了齿轮高速干切滚刀的失效形式和失效原理,提出了以单个刀齿切削长度为高速干切滚刀寿命评价指标并建立相应计算模型的方法,基于此开展了高速干切滚刀寿命试验,建立了高速干切滚刀寿命多元线性回归模型,采用MATLAB求解得到该试验条件下的高速干切滚刀寿命经验公式。最后基于此提出了通过优化滚切工艺参数以及采用新型窜刀方式等来延长高速干切滚刀寿命的方法。     

STUDY ON WEAR AND DESTRUCTION OF HOB IN GEAR HOBBING

The wear and destruction appearances of hobs are researched. The reasons of the wear and destruction of hobare analyzed. And the influence of the change of the bobbing force and the bobbing temperature on the wear and destruction of hob in gear bobbing is also analyzed. In gear bobbing, the main wear mechanisms are adhesion and ploughingwhen cutting the 20CrMnTi gear using W18Cr4V high-speed steel hob.     

Effect of hob wear on the surface layer properties of hobbed gear teeth

Results of investigations of the effect of hob wear on the surface layer properties of hobbed gear teeth are presented in this paper. The influence of hob wear on the microhardness, surface roughness, residual stresses and surface layer thickness were investigated. On the basis of the experimental results it was found that hob wear has a significant influence on the surface layer properties of the gear teeth. This influence is most noticeable on the dedendum and root fillet where the gear tooth space is shaped by the bluntest part of the hob cutting edges.     

A method for predicting hobbing tool wear based on CNC real-time monitoring data and deep learning

Intelligent monitoring and diagnosis of tool status are of great significance for improving the manufacturing efficiency and accuracy of the workpiece. It is difficult to quickly and accurately predict the wear state of worm gear hob under different working conditions. This paper proposes a novel approach to predict hob wear status based on CNC real-time monitoring data. Based on the open platform communication unified architecture (OPC UA) technology and orthogonal test, the machine data of motor power, current, etc. related to tool wear are collected online in the worm gear machining process. And then, an improved deep belief network (DBN) is used to generate a tool wear model by training data. A growing DBN with transfer learning is introduced to automatically decide its best model structure, which can accelerate its learning process, improve training efficiency and model performance. The experiment results show that the proposed method can effectively predict hob wear status under multi-cutting conditions. To show the advantages of the proposed approach, the performance of the DBN is compared with the traditional back propagation neural network (BP) method in terms of the mean-squared error (MSE). The compared results show that this tool wear prediction method has better prediction accuracy than the traditional BP method during worm gear hobbing.     

Effect of hob wear on the sounds emitted in the gear hobbing process

Increasing demand for precision and economy in gear manufacture necessitates control of the essential parameters in the hobbing process. Recognizing this necessity, research was undertaken to develop a hob wear detector. Using an empirical procedure, the acoustic signal emitted in hobbing was assessed with respect to its capacity to provide information about the extent of hobbing cutter wear. It was shown that signals from measurement of acoustic pressure in full bandwidths are unsuitable for the purpose. Frequency analysis of the acoustic signal enabled a third-octave frequency range with a centre frequency of 160 Hz to be singled out, wherein the acoustic signal level showed a close correlation with hob wear. The suitability of the signal is independent of most of the basic machine and process parameters and, for the purposes of hob wear detection, is reduced with higher values of module pitch of the hobbed gear     

Investigation of the effects of alumina nanoparticles on spur gear surface roughness and hob tool wear in hobbing process

Hobbing process is one of the machining methods in manufacturing spur gears. In machining processes, selecting a suitable lubricant is one of the significant factors in enhancing machining productivity and improving the characteristics of manufactured workpieces. This study has used the nanolubricant including alumina nanoparticles dispersed in mineral-based oil 25W-50 in hobbing process. Then, hobbing process using the lubricant including both nanoparticles, and none has been done utilizing with the similar hob tools. Two spur gears with DIN1.7131 material have been manufactured using each of two lubricants. Then, the hob tool wear and surface roughness values of manufactured spur gears were investigated. Comparing the results show that using lubricant including alumina nanoparticles in hobbing process causes an expressive decrease in the hob tool crater and flank wear. Also, arithmetic surface roughness value in spur gears manufactured with nanolubricant has decreased.     

A 3D chip geometry driven predictive method for heat-loading performance of hob tooth in high-speed dry hobbing

High-speed dry hobbing is an emerging green technique for gear hobbing owing to its high productivity and environmental friendliness. However, severe friction occurs and heat instantaneously accumulates in the cutting region due to the adoption of high cutting speed and the lack of metalworking fluids, which causes serious hob wear. This investigation is concerned with the thermal performance and heat-loading quantitative method of hob cutter in high-speed dry hobbing. According to the multiple-edge and intermittent cutting behavior, the temporal dynamic characteristics of hob cutter are analyzed. Based on the complex 3D chip geometry produced in high-speed dry hobbing, the calculation method for heat-production (the amount of generated cutting heat) of hob tooth is proposed. Considering the coupling effects of heat conduction, heat convection, and heat radiation, the prediction model for heat-loading quantity (the bearing capacity of cutting heat) of hob tooth is developed. With the help of the developed method, the interrelation between the thermal performance of hob cutter and material removal volume, cutting conditions, coating material, respectively, are investigated. The predictive method developed in this work provides a methodology for process parameter optimization and hob cutter manufacturing of high-speed dry hobbing.     

Reproducing wear mechanisms in gear hobbing—Evaluation of a single insert milling test

Gear hobbing is a widely used method in industrial gear manufacturing. The most common type of hob is made of homogenous HSS and protected by a PVD coating. In order to increase the reliability and tool life of these milling tools, further developments of the tool surfaces and cutting edges are necessary.A single tooth milling test, using a HSS insert in a conventional milling machine, has been developed with the aim to reproduce the wear mechanisms seen on real HSS gear hobbing teeth. The benefits of such a test, compared to actual gear hobbing tests, are primarily accessibility and reduced costs for both design and production of test specimens (inserts).The main goal of this study was to verify that the wear mechanisms in the developed test correspond with the wear mechanisms obtained in real gear hobbing. Once this was verified, the influence of surfaces roughness on the performance of TiAlN coated HSS inserts was evaluated by using the tool as delivered or after polishing the tool surfaces. Parameters considered were tool wear, cutting forces and the quality of machined surfaces. The polished inserts, yielded less adhered work material and reduced flank wear but no significant difference in cutting forces as compared to the unpolished inserts.