海顿《G大调钢琴奏鸣曲》(Hob.ⅩⅥ:6)中的结构布局探究

18世纪中叶,海顿创作了大量钢琴奏鸣曲,为古典主义时期奏鸣曲体裁的迅速发展做出了重要贡献。其中以《G大调钢琴奏鸣曲》(Hob.ⅩⅥ:6)为代表的19首早期钢琴奏鸣曲对奏鸣曲结构布局的确立与奏鸣曲式结构的完善产生了重要影响。

Cutting Force Fluctuation Suppression and Error Homogenization of Noncircular Gear Hobbing Based on the Tool Shifting Method

The current research on noncircular hobbing mainly focuses on the linkage model and motion realization.However,the intermittent cutting characteristics of hobbing would increase uncertainties in the manufacturing process.In this paper,a hobbing machining model with tool-shifting characteristics was proposed to solve the problems of cutting force fluctuation and inconsistency of tooth profile envelope accuracy at different positions of the pitch curve in noncircular gear hobbing.Based on the unit cutting force coefficient method,the undeformed chip volume generated by interrupted cutting was used to characterize the fluctuation trend of the hobbing force.The fluctuation characteristics of the cutting force generated by different hobbing models were compared and analyzed.Using the equivalent gear tooth and hob slotting numbers,an analysis model of the tooth profile envelope error of the noncircular gear was constructed.Subsequently,the tooth profile envelope errors at different positions of the pitch curve were compared and analyzed based on the constructed model.The transmission structure of the electronic gearbox was constructed based on the proposed hobbing model,and the hobbing experiment was conducted based on the selfdeveloped noncircular gear CNC hobbing system.This paper proposes a hobbing method that can effectively suppress the fluctuation of the peak and whole circumference cutting force and reduce the maximum envelope error of the whole circumference gear teeth.

利用ЛЯПУHOB函数研究某些振动的稳定性

在工程技术中,振动是一种常见的运动形式,研究它的稳定性具有重要的实际意义。本文利用第二方法,先从单摆振动入手,进而研究几种阻力是位移或者是速度的非线性关系情况下系统的稳定性。 1.单摆的无阻尼振动它所满足的微分方程为 d^2θ/dt^2+g/l sinθ=0 (1)

STUDY ON WEAR AND DESTRUCTION OF HOB IN GEAR HOBBING

The wear and destruction appearances of hobs are researched. The reasons ofthe wear and destruction of hob are analyzed. And the influence of the change of the hobbing forceand the hobbing temperature on the wear and destruction of hob in gear hobbing is also analyzed. Ingear hobbing, the main wear mechanisms are adhesion and ploughing when cutting the 20CrMnTi gearusing W18Cr4V high-speed steel hob.

牛骨胶原蛋白肽促进HOB增殖

目的研究牛骨胶原蛋白肽(Bovine Collagen peptides,BCP)对人成骨细胞(Human Oseoblast,HOB)增殖的影响。方法分离培养HOB,茜素红染色鉴定HOB的成骨特性,利用MTT实验检测胶原蛋白肽对HOB的增殖,流式细胞仪测定胶原蛋白肽对HOB细胞周期。结果茜素红矿化染色结果表明,HOB具有成骨能力。MTT实验表明0.3 mg/ml胶原蛋白肽能显著促进细胞的增殖,并能增加G2+S期的百分含量。结论牛骨胶原蛋白肽能够促进HOB增殖,为骨质疏松的预防和治疗提供理论依据。

Mathematical Model and Machining Method for Spiral Flute Rake Faces of Hourglass Worm Gear Hob

To improve the cutting performance of an hourglass worm gear hob and the accuracy of the resulting worm gear,the rake angles of the teeth on the pitch circle should be reduced.A method of forming the spiral flutes by using a variable transmission ratio was developed.This method ensures that the rake angles on the indexing torus of each tooth are approximately 0°.Based on the gear meshing theory and the hourglass worm forming method,the discretization mathematical model of the rake face of a planar double enveloping worm gear hob was established by using cylindrical generating surface,and the feed parameters for machining the rake face for a variable transmission ratio were obtained.The spiral flute was simulated and the hob was machined on a four axis CNC milling machine.A contourgraph was used to measure the rake angle.The measurement results showed that the proposed method can reduce the absolute value of the rake angle on both sides of the cutting teeth,which can be used for machining the spiral flute rake face of an hourglass worm gear hob.

VARIABLE INERTIAL DAMPER AND ITS APPLICATION IN ZERO-DRIVE GEAR HOBBING MACHINE

A variable inertial damper, whose viscous damping coefficient can be adjusted by changing the gap between inertia wheel and motor spindle, is designed in servomechanism of zero-drive hobbing machine and is directly attached on the motor spindle. The mathematical model of servo system with inertial damper is built. By using theoretical analysis and system simulation, it is demonstrated that the variable inertial damper with optimal damping coefficient and moment of inertia should lead to no resonance point in wider frequency range of exciting force. Therefore, its application in zero-drive hobbing machine makes this system not only achieve higher system stiffness to overcome load torque fluctuation, but also gain better stability.

Improved Relief Grinding Method of Gear Hob with Equal Relief Angle

The regrinding error is the main factor affecting the eligible length of hob tooth,how to decrease the regrinding error is a hot issue in the research area of hob grinding.At present,researches focus on changing the trajectory of relief moving,because of no unified relief grinding path planning method,the research result is restricted in the practical application.For solving the problem,the calculation model of the hob relief angle is established with the Archimedes relieving motion to analyze the interaction between the increasing relief angle of the hob and the accelerating tooth profile errors.Based on it,the improved relief grinding method of gear hob is proposed with equal relief angle（ERA）.Furthermore,the relief grinding method with ERA is developed with the following two steps.Firstly,the convergence numerical solution algorithm of the tooth top curve is designed to form the wheel motion path which is compared with that of traditional grinding.The second step is to establish the solution model of ERA grinding wheel.In order to verify the effect of the method,hob grinding simulation system of 3D solid was built under the AutoCAD environment.The regrinding errors is analyzed by intercepting the hob axial profiles of the various regrinding angles with Boolean operations and further converting it to basic rack tooth,then the simulation example of zero rake straight flute hob is used to compare the regrinding errors between ERA grinding and traditional grinding.Finally,the experiments were implemented on the five-axis CNC relief grinder with the relief motion of ERA grinding driven by cam.The results of experiments show that the method can effectively reduce the regrinding errors of hob and grind expediently gear hob of AA rank and over.This research provide an effective model of relief moving path plan reducing regrinding error,and have practicable value in CNC relief grinder.

HOB-A助剂在催化裂化装置的工业应用

介绍了汽油辛烷值桶助剂HOB-A在某公司1.05 Mt/a MIP-CGP(多产异构烷烃和丙烯)催化裂化装置上的工业应用情况。结果表明:在HOB-A助剂占系统藏量质量分数达到9.3%的情况下,与空白标定相比,汽油收率从38.32%提高到38.57%,研究法辛烷值从93.5提高到94.5,汽油辛烷值桶相对提高1.73%,丙烯质量收率从9.23%提高到9.77%,总液体收率提高了0.86百分点。对使用HOB-A助剂前后的经济效益进行测算,使用辛烷值桶助剂后,催化裂化装置的经济效益得到了较大的提升。

Design and Machining of Combination Gear Cutter Hob

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Research on Applying Nano Cutting Oils in Spur Gear Hobbing Process

Nanolubricant mixing the normal lubricant with nanoparticles, gradually becomes a new trend study for metal cutting enhancement. An addition of the nanoparticles improves lubricating properties and convective heat transfer coefficient (cooling properties) of nanolubricants. In the present work, nanolubricant is formulated by using dispersions of 0.3% Al2O3 nanoparticles in normal industrial oil VG46 for enhancement of gear machining performance of SCM420 steel. Comparative study of flank wear, crater wear and gear profile error in gear hobbing with normal oils in the existing production line as well as nanolubricant is studied. This study clearly reveals that tool wear, and gear profile error are reduced by the use of nanolubricant compared to that of normal oils. The paper results not only contribute the deeper understanding of the novel performance of nanoparticles in conventional cutting fluids, but also show a very promising solution to achieve the engineering economy effectiveness in gear machining.

THEORY OF HELICOID OF SPHERICAL HOB

The mechanism of spherical hob's cutting internal gear is explained and the new coneeptof generating gear of spherical hob is presented. The reason why there is theoretical error and thenew method of decreasing the error are also analysed. Some new equations about the mainparameters, the equations of helicoids, the equations of cutting edges and the flank angles of spheri-cal hob are given.

YKJ3180H Economy NC Gear Hobbing Machine

The YKJ3180H Economy NC GearHobbing Machine is a new variety,developed recently by the ChongqingMachine Tools Works to meet clients’demands. Its most prominent feature is its highproduction efficiency ( able to complete awork cycle automatically), high processingprecision (Grade 7 or higher according to theGB 10095) and its cost competitiveness. This product is used in the machinetool and machinery industries at automobiles,tractors, gears and gear box factories. It canbe used for processing spur gears and helicalgears, automatic radial feed wormwheels,tapered gears and crowning gears; so it isespecially applicable in factories usingcrowning gear couplings, such as metallurgy,mining, lifting transport and the chemicalmachinery.

Research and Development on NC System of Gear-hobbing Machine based on Zero-programming Technology

By the analysis of roller gear processing technology, combining with gear meshing mechanism and motion relationship, models for rolling gear machining parameter and zero-programming are established. In this paper, the automatic generation technology of NC program for CNC gear machining process has been studied and the zero-programming system architecture of open CNC gear-hobbing machine has been presented. In the design and development of the system, human computer interaction, programming algorithm and the design of each function module have bean done. Application test shows that the expected design requirements have been achieved.

STUDY ON THE CUTTING TEMPERATURE IN GEAR HOBBING

According to work tool thermocouple principle,the equipment for measuring hobbing temperature is developed.The changing character of cutting temperature in gear hobbing,the relation between cutting conditions and hobbing temperature,and the influence of cutting conditions on hobbing temperature are discussed by means of experiments.All these have provided the reference standards for the equitably selecting cutting conditions and geometrical parameter of hob,prolonging the life of gear hobs,and predicting processes of gear hobbing.

ЛЯПУHOB——Lichtenstein型算子的固有函数

关于ЛЯПУHOB——Lichtenstein型算子(?)的非负连续固有函数及其正固有值的存在性已有不少结果(见(1-3))

Numerically investigating the crushing of sandstone by a tooth hob

To investigate the mechanical process that occurs between rocks and tooth hobs,the crushing of sandstone with a tooth hob was simulated using reconstructed multi-mineral mesoscopic numerical models of various grain-sized sandstone samples.When a piece of sandstone is crushed by the tooth of a hob rolling at a constant speed,the resultant reaction forces of the sandstone on the tooth first hinder and then contribute to the rolling of the hob.The absolute value of the longitudinal reaction force is significantly higher than that of the lateral reaction force.Because the tooth was subjected to reaction forces from the sandstone,forces and moments were applied to the hob in order to keep the hob rolling.The applied forces were equal in value and opposite in direction to the reaction forces of the sandstone on the tooth.Three typical curves of the work done by the applied forces and moment were obtained,and the contribution of the applied lateral force and moment to the total work done for crushing sandstones was variable;however,no work was done by the applied longitudinal force.Moreover,the applied longitudinal force and total work were positively correlated with the strength of sandstone samples.The total work,applied forces,and moment increased with the maximum penetration depth of the tooth in the sandstone.

非圆齿轮滚齿切削力波动特性及抑制研究

滚齿是非圆齿轮加工实现的重要方法,用于节曲线外凸直或斜齿非圆齿轮的高效高精制造,节曲线非圆特性导致滚切力呈现较大幅度波动,影响制造过程稳定性及加工精度,是非圆齿轮滚齿领域需要研究的重要课题。文章基于单位切削力计算原理及圆柱齿轮滚切力的研究成果,采用单次断续切削产生的未变形切屑体积表征滚切力波动态势,构建非圆齿轮滚切未变形切屑模型的获取方法。选取大偏心率卵形齿轮为研究对象,分析滚刀恒速不窜刀联动加工模型所产生的滚切力波动特性,得出该联动加工模型所对应峰值切削力的波动规律。提出一种滚刀恒速并附加窜刀的联动加工模型,该模型具有恒定弧长增量加工特性,对抑制整周滚切力波动具有重要意义,并开展不同滚切深度所对应滚切力波动规律研究,研究结果为非圆齿轮滚切方案的优化制定提供一定的理论依据。

水射流构造自由面下滚刀线性切割破岩特性研究

为了分析水射流构造自由面情况下的滚刀切割破岩特性,本文采用有限元模拟分析方法,建立自由面工况下滚刀破岩模型,模拟不同切宽下滚刀切割岩石动态过程,得到水射流构造自由面工况下滚刀破岩载荷、破岩状态等变化规律,并利用线性切割实验进行验证。研究结果表明:水射流构造自由面后滚刀切割过程中,岩石会产生表面和内部拉伸裂纹,且当切宽小于临界值50 mm时,滚刀临近自由面侧的拉伸裂纹可以延伸到自由面,促进岩石破碎;水射流构造自由面情况下的滚刀破岩垂直载荷最大,侧向载荷最小,且合适的切宽可以显著改善滚刀受载;当滚刀能有效利用水射流构造的自由面破岩时,其破岩比能耗远低于无自由面效应下的滚刀破岩比能耗,前者仅约为后者的30%,破岩效率得到显著提高。研究结果可为水射流辅助滚刀破岩参数设计提供依据。