Aufbau und Validierung eines Prozesskraftmodells für das kontinuierliche Wälzschleifen von Stirnradverzahnungen

Case hardened gears usually are hard finished to improve the load carrying capacity and the noise behavior. Generating gear grinding is one possible process for the hard finishing of gears and has replaced other grinding processes in batch production of small and middle size gears due to the high process efficiency. Despite the wide industrial application of this process only a few scientific analysis exist. The science-based analysis of generating gear grinding needs a high amount of time and effort. One reason are the complex contact conditions between tool and gear flank, which change continuously during the grinding process. This complicates the application of the existing knowledge of other grinding processes on generating gear grinding. The complex contact conditions lead to a high process dynamic which is a challenge for the design of machine tools, the control engineering and the process design. The knowledge of the cutting forces and their time dependent behaviour is necessary to describe and optimize the process dynamic. But the determination of the cutting forces in generating gear grinding process is not facilely possible at this time.     

Ermittlung des Verformungs- und Steifigkeitsverhaltens von bombierten Profilwellenverbindungen mit Evolventenverzahnung

Crowned shaft couplings with involute splines are an important transmission element in mechanical engineering and offer a wide variety of applications in the field of gears and transmissions. The advantages are the simple mount methods and the possibility to transmit large and impulsive torques. Especially the straight cylindrical involute splines are one of the most effective and powerful shaft-hub joints. One of the significant parameters for the design of shaft-hub joint is the knowledge of the deformation and stiffness behaviour. This exciting topic has filled a multitude of publications in the past decades. In the current technical literature exists no acceptable reference of contemporary dimensioning for specific gear tooth shapes. This includes crowned gear tooth shapes with involute splines which are for example applied in gear couplings. The following pages will show that the deformation and stiffness behaviour of gear tooth profiles according to DIN 3960 and DIN 5480 can be calculated simple and sufficient with current analytical methods.     

Potenzial von freien Flankenmodifikationen für Beveloidverzahnungen

In recent years the beveloid gear, also known as conical involute gear, is shifting more and more into the spotlight. The beveloid gear has been an important part of marine transmissions for years and is nowadays used to transmit the torque of the output shaft of the gearbox onto the front axle in a four wheel drive vehicle. The small need of design space and the reduced amount of design parts necessary in comparison to conventional transfer gearboxes, distinguish the beveloid gear. The conjugate flank of beveloid gears promises the best operational behavior. However because of its geometry the conjugate flank cannot be manufactured with standard manufacturing processes. Standard modification such as crowning offer a possibility to enhance the operational behavior of involute beveloid gears but cannot reach the whole potential given by conjugated beveloid gears. Therefore, the objective of the following report is to investigate the potential of free flank modifications of beveloid gears regarding the operational behavior. After a brief overview on existing geometry optimization methods for beveloid gears, the method for free flank modifications by means of a weighted objective function is defined and applied to an example gear. The results of the investigation show that free flank modifications offer a high level of improvement of the operational behavior. The comparison with a non-modified gear, a gear with standard modifications and a gear with free flank modifications for three different load steps proves that free flank modifications offer a higher durability and lower noise excitation.     

Einfluss einer gezielt aufgeprägten Mikrogeometriestreuung auf das Anregungsverhalten von Kegelradverzahnungen

In the design process of transmissions, one major criterion is the resulting noise emission of the powertrain due to the gear excitation. Within the past years, a lot of investigations have shown that the noise emission can be correlated to the quasi-static transmission error. Therefore, the transmission error can be used as a characteristic value for quality assurance by experimental inspections as well as for a tooth contact analysis in the design process.The noise behavior of gearboxes is mainly caused by the excitation in the tooth mesh. The standardized design and calculation methods for gears concentrate on the reduction of the excitation level. But often the physical sound characteristics do not fit in with the human noise perception. Thus gear design rules are required that are able to rate the excitation according to the perception.The effect of the targeted topography scatter generally described is the reduction of the gear mesh amplitudes with an increase of the background noise. The objective of the report is to develop an understanding of the influence of different micro geometry scatters on the excitation behavior.Finally, it is the aim to design an aurally-accurate micro geometry scattering for the optimization of ground bevel gears in terms of tonality reduction and increased background noise. By means of a variant calculation and weighted target variables, psychoacoustic optimized micro geometry scattering is designed. At the same time, attention is also focused on a simple production of mixed topographies.     

Möglichkeiten und Grenzen der Miniaturisierung von Ionisationsvakuummetern

The current mainstream trend in the modern vacuum measuring technique is significantly characterised by the development and the production of miniaturised vacuum gauges. By the help of modern techniques of micromachining, in the past years the most important basic operation principles of pressure measurement were already utilised in micromachined vacuum sensors. But solely the miniaturisation of ionisation gauges, the only practical gauge type for the use in the high and ultra high vacuum range, was without success (up to now). The arising difficulty results from their basic operation principle which limits the miniaturisation of this vacuum gauge type. Within the scope of this work, the reasons for the limitation of the miniaturisation of ionisation gauges will be explained and discussed.     

Evaluation of gear noise behaviour with application force level

Reducing excessive vibration and undesired noise is one of the most important goals throughout the whole development phases of gearboxes. Among different development stages, different technical measurements are available to estimate the excitation behaviour of gear meshes.However, the comparison of the result of these measurement types among the development stages may be inconsistent due to different dimensions. In order to ensure the best comparability as well as comprehensive interpretation of the vibration characteristics of gear meshes, an application force level was developed. This characteristic value allows noise behaviour evaluation by means of different measurement types. Moreover, the evaluation boundary of this characteristic value is customizable to encourage the flexibility for further specific evaluations.In this article, the formulation of application force level is derived and its usage is shown. Although the application force level was intentionally developed for the gear design, it can also be applied to other kinds of application fields. The application force level is the result of the research project funded by the German research association for drive technology (FVA).     

压花艺术在现代家具设计中的应用

目的 压花艺术源于自然,回归自然,具有独特的魅力,也具有极高的实用价值和艺术价值。研究压花艺术在现代家具设计中的应用,不仅是对压花艺术的探索,而且为家具设计提供了新思路。方法 以压花艺术为研究对象,分析了压花艺术的设计应用现状及压花创作的方法和制作过程,深入剖析了压花艺术系列产品视觉语言,探讨了压花艺术在现代家具中的创新思路和设计方法。结论 压花艺术作为内涵丰富的花卉艺术中的一个门类,其潜在内涵、生命力和艺术表现力,可为现代家具设计研究提供参考思路和实践指导。基于压花艺术进行家具设计案例的探讨及实践论证,旨在为传统艺术运用于现代设计提供借鉴。     

Auslegung und Fertigung von UHV‐Kammern

Design and manufacturing of UHV chambers The selection of materials, the finish of the surfaces, the design of the construction: What influence do these factors have in the area of ultra‐high vacuum? Which pumping power is actually required for the respective application? Why can it be difficult to achieve a suitable end pressure? The author gives an overview of the key points to be considered when designing and manufacturing chambers for the UHV. The article is not just about manufacturing, it also touches product safety and risk assessment issues.     

饕餮纹在现代包装设计中的美学探究

通过分析包装设计中传统图案在设计理念及制作过程中的作用和影响,并结合几个典型实例论述了饕餮纹饰在包装设计中的形式美法则的体现,以及民族性与时代感的象征意义,从而阐述了饕餮纹饰在现代包装设计中的重要作用及意义。并说明了应将饕餮纹进行提炼、变形、再次组合,将其作为一种艺术符号与现代艺术设计紧密联系起来,巧妙地应用在各类产品包装设计中。这样,既可以弘扬发展民族传统文化,也能顺应现代包装设计思潮。     

Schmelzen und Behandeln von Metallen und Legierungen im Vakuum

The growing demands for better quality of metallic materials can only be met by the application of vacuum during the production of these metals and alloys and their field of application.     

Grundlagen,Herstellung und Anwendungsaspekte des Supersolidus Flüssigphasensinterns von hochlegierten Werkzeugstählen und Metallmatrix‐Verbundwerkstoffen

Principles, manufacturing and application aspects of super solidus liquid phase sintering of high‐alloyed tool steels and metal matrix composites Iron‐based metal matrix composites (MMC) are applied for abrasive wear resistant applications. A common production route uses hot isostatic pressing (HIP) of metal and carbide powders, a comparatively cost intensive process. Using high‐alloyed tool steels as matrix materials it is possible to obtain dense materials by liquid phase sintering with an internally formed liquid phase. This contribution describes the basic principles of densification of the matrix materials taking thermodynamic calculations into consideration. It points out a production route for processing particulate reinforced, high wear resistant composite materials by sintering. Beside the sintering behaviour concepts for heat treatment as well as the abrasive wear resistance are discussed.     

Chemie gegen Reibung und Verschleiß: Untersuchung molekularer Wirkungsmechanismen von Schmierstoffadditiven

Chemistry against friction and wear: Examining surface reactions of lubricant additives Although greases and oils are able to reduce friction without other substances being added, blending with additives is essential for todays high‐performance lubricants. Only these synthetic additives yield the desired characteristics of the final product, which is often designed specially for a particular application. In most cases, however, the underlying chemical mechanism is not exactly understood. For anti‐wear additives it will be shown how modern surface chemistry can help to understand the effectiveness of those substances and thus contribute to a systematic additive optimization.     

刨齿刀的三维可视化设计

三维参数化、可视化设计是现代机械设计的发展趋势之一。在AutoCAD软件的二次开发工具VBA(visual basic for application)中,开发了刨齿刀三维参数化和可视化设计软件。在AutoCAD软件中进行刨齿刀三维参数化建模,利用生成的刨齿刀三维实体模型,在Pro/Engineer,ANSYS软件中进行刨齿刀有限元分析。制造了硬齿面圆锥直齿轮刨齿刀,对刀具的磨损进行分析,为刀具的快速开发提供条件。     

Systeme von elektronischen Kurvenscheiben

Electronic cam systems are modern means for flexible industrial automation and are used to implement the motion functions of working links of production and handling mechanisms. One of the several high-end drive systems is used to investigate the general dynamics properties of electronic cams. It is called an electronic cam system because the application is an integration of servomotor control (controller, servo-inverter, regulation, displacement law), input and output drives, communication and the own software of the control system, including the combination of the servo drives with conventional gearboxes.     

平衡式外啮合余弦齿轮泵结构和性能研究

基于普通齿轮泵存在流量品质差、径向力不平衡等缺陷,提出一种新型平衡式外啮合余弦齿轮泵设计方案.这种新型余弦齿轮泵,既保留了普通齿轮泵的结构特点,又具有流量品质较好、功率密度较高、中心轮所受径向力平衡和排量大等优点.研究了中心轮齿数对泵流量脉动率的影响,研究结果表明：新型余弦齿轮泵的流量脉动率只有普通余弦齿轮的1/3,提高了齿轮泵的流量品质.因此这种新型齿轮泵可拓展齿轮泵的应用领域,有一定的研究和应用价值.     

An automatic design optimization procedure to minimize fillet bending stresses in involute spur gears

This paper presents the development of an automatic design algorithm for gears. The criterion on which the design performance is assessed is the maximum tensile stress induced in the gear tooth fillet under service conditions. Starting from an initial set of design parameters the stresses in the gear tooth fillet are calculated. The maximum value of the stress is then expressed as a function of the design variables. By minimizing this function, the objective function, subject to both equality and inequality constraints a new set of design parameters, is produced. Iterative application of the analysis and minimization stages forms a sequence of non-linear optimization problems which converges to yield the optimal design. Finite element techniques employed to calculate accurately the stresses in the gear tooth are again used to compute the design derivatives. This process is very economical, owing to its efficient reuse of the factorized stiffness matrix. The algorithm is illustrated by its application to a spur gear tooth of involute profile. Both linear and non-linear forms of the objective function are used and a comparison made between the solutions obtained.     

基于力耦合的非谐振单元组成的超声变幅器设计

传统的超声振动系统全谐振设计方法要求组成超声振动系统的各个单元有相同的谐振频率,各个组成单元的结构尺寸由谐振频率确定,而超声珩齿系统中的齿轮结构尺寸是由它的使用要求决定,是非谐振单元,不能用全谐振理论设计,本文采用力耦合方法,将齿轮简化为环盘,将它和变幅杆组合并联合建立动力学方程,实现了非谐振单元组成的超声变幅器的设计。     

明式风格在现代家具设计中的应用研究

目的探究明式风格在现代家具设计中的应用。方法从现代家具设计的不足谈起,分析明式家具的雅致含蓄、不落俗套、天人合一,三大风格特征及其对现代家具设计的理论支持,最后以现代橱柜设计为例,从造型、材料两方面对明式风格的借鉴进行详细论述。结论明式家具典型的风格特征是现代家居设计的灵感源泉。在进行现代家居设计时,设计师要对明式传统家具造型及其整体的风格特征进行提炼,汲取明式家具的精华,使其与现代家具工业化大批量生产的特点完美融合,如此才能创造出既有中国特色,又能面向世界的现代家具产品。     

Influence of surface layer properties on tooth root bending strength of cylindrical gears

The trend of resource-efficient machine elements confronts design engineers with new challenges. Reduced component weight and ever increasing power densities require a gear design that enters the border area of material capacity. To embrace the potential offered by modern construction materials, calculation methods for component strength must rely on a deeper understanding of fracture and material mechanics in contrast to empirical-analytical approaches.The aim of lightweight designs in drive technology – particularly in relation to E?mobility – can lead conventional design methods towards larger dimensioned and therefore heavier gears. Calculation methods that empower an accurate depiction of local load and material properties are able to safely push the boundary of gear design into areas that are closer to the ultimate fatigue limit of the material and help to conserve resources that way. For this reason, the aim of the report is to prove a general applicability of the higher-order calculation approach developed by Henser for all gear geometries and material properties. This method will make for more cost- and weight-effective gear design in the future.A two step approach shows the accuracy of the Inclusion-Based Weakest Link Model by validation on a small module helical gear and a parameter study proves the effectiveness of the Inclusion-Based Weakest Link Model by showing the influences of different sized gear geometries and material properties on calculated bending strength. In addition, the main influence parameters on the model and material properties that have different effects depending on gear size are identified.     

Determining the load distribution by measuring the tooth root stresses

Forschung im Ingenieurwesen - A main goal in the design of modern gearboxes is to achieve an equal load distribution within the gear meshes for a certain nominal load....