圆柱斜齿轮锻造成形技术

介绍了圆柱斜齿轮塑性成形的2种方法,滚轧成形与浮动凹模成形。针对2种成形工艺,分别以不同型号的圆柱斜齿轮为对象进行了数值模拟与试验研究,探索了齿轮在不同工艺下,金属流动规律、成形缺陷及成形力等。结果表明：圆柱斜齿轮采用滚轧成形可有效避免脱模困难,且整个过程属于局部加栽,对设备要求简单。浮动凹模成形可有效降低成形载荷,较传统工艺载荷下降近30个百分点,脱模时,锻件齿形在模腔内沿螺旋方向做刚性平移运动,一定程度上保证了锻件的精度。     

齿轮的滚压塑性成形技术的研究现状

运用滚压成形技术进行齿轮塑性加工具有设备简单、刀具寿命长及效率高的特点,尤其对斜齿轮的成形加工,没有拔模问题。近年来,在国外该技术的研究与运用得到极大的重视。文章对这些研究成果进行介绍,主要内容为滚压成形方法、冷和热挤滚压成形时出现的问题及解决措施。期望能对认识滚压成形的内在规律有所帮助。     

汽车中小模数齿轮冷滚轧技术研究

阐述了中小模数齿轮零件冷滚轧技术的工艺、模具、坯料和工装夹具的设计方法和要点。分析了汽车转向器转向齿轮零件的结构特点及采用冷滚轧成形工艺加工的技术要点;并设计出了转向齿轮的冷滚轧工艺和滚轧轮;进行了滚轧轮与工装的安装、调试和冷滚轧工艺的试验研究。滚轧出了符合用户要求的转向齿轮零件。     

Deformation model of a thermomechanical gear finishing process

A low temperature thermomechanical precision finishing process is being developed in which ausforming and gear rolling are being combined to result in lower processing costs and improvements in final properties compared to conventional gear finishing processes. Since the ability to predict the deformations and loads is an important key to the success of the process, a numerical model is being developed to study the effect of forming operations on strains and displacements. This paper describes the current status of the program. The finite element program has been verified by solving a cylinder upsetting problem for which both experimental and numerical solutions are well documented. Nonlinear formulations due to material, geometry, and contact conditions have been modeled in the program and their application to the gear finishing processes has been demonstrated. The final tooth contour on both the approach and trailing sides of an 8.5 diametral pitch spur gear have been predicted.     

Development of a warm cross wedge rolling process using FEA and downsized experimental trials

Cross wedge rolling is a forming technology that offers a lot of advantages: No flash occurs, cycle times are low, lubricants are not necessary and the machines are easy to automate. Currently, cross wedge rolling is applied at hot temperatures only. An adaption of this technology to warm temperatures (about 500?C950?°C) can increase the geometrical spectrum of warm forgings. The advantages of warm forged parts in comparison to hot forged parts are closer tolerances, reduced surface roughness, no scale and reduced decarburization. To apply cross wedge rolling at warm temperatures, the possibilities of defects e. g. internal voids and improper formed work pieces must be analysed. This paper describes the development of a warm cross wedge rolling process with one area reduction. The paper also includes results of finite element analysis (FEA), experimental trials with a downsized work piece and the adaption to the industrial work piece in original size. In the FEA simulations tools with serrations on the side have been used. The downsizing method is explained and the difference between FEA, downsized and originally sized work piece with the focus on forming forces, temperature distribution and defects are presented.     

Investigation of work hardening of flat-rolled helical-involute gears through grain-flow analysis, FE-modeling, and strain signature

Net-shape forming of gears is under investigation by a number of researchers. The proposed new methods would reduce waste through chip elimination. Flat rolling of external-precision involute-helical gears is discussed in the current paper. This method is expected to have the additional advantage of producing stronger gears. The work-hardening effect on the critical regions of gear is investigated through the use of three-dimensional DEFORM finite element models (FEM). The simulation models were calibrated against designed experiments with a specific gear design. Also, current production gears were compared with gears manufactured through the new process. Samples were destructively tested to obtain metallurgical data. Hardness maps and grain-flow photographs were produced for the two groups of gears. Validation of FE modeling has opened the way for optimization of gear-rolling process through virtual design of experiments (DEX). It would be possible to vary FEM inputs such as blank material, gear specification, or die geometry and study the predicted impact on gear tooth strength.     

Description of the interactions during gear rolling as a basis for a method for the prognosis of the attainable quality parameters

Gear rolling develops increasingly to an economic alternative for the production of highly exact gears. Crucial criterion for broad industrial application of gear rolling is thereby the attainable gear quality. This depends at present still on a process and machine design, which is based on empirical expert knowledge. In order to finally develop a method, which makes a sufficiently safe prognosis for the attainable gear quality possible on the basis of real process data, in the context of a interdisciplinary research project the relevant interactions of the system machine-tool-process are determined, described and modeled in suitable form. Apart from the fundamental aspects of this problem the contribution argues in particular with the problem of the influence of the interactions of the machine system on the pitch accuracy of gear teeth.     

An assessment of finite element software for application to the roll-forming process

The roll forming industry has many difficulties in product development and process set-up. The design and development of rolls and processes are mainly based on trial-and-error and past experiences. Recent industrial trends demand products having high quality and tight tolerances. This requires more precise and cost-effective roll-forming processes than the ones employed in the traditional product development methods.

SHAPE is a reliable FE based solution provider, which covers a wide range of roll forming and rotary forming simulations including ring rolling, tube spinning, flow forming, and thread rolling. It also provides powerful analysis tools for heat transfer, roll stress and microstructure analyses. In this chapter the technical capability of SHAPE for roll forming is assessed by studying an industrial problem. The accuracy and robustness of the software is evaluated using machine shop results.     

Rotary straightening of curved shape near both ends of seamless pipe

A new straightening method is proposed for the curved shape near both ends of seamless pipe by using a rotary forming process with three rollers. A helical rolling mill with three rollers was used in the experiment. The prebend aluminum seamless pipes were straightened under various working conditions. It was found that the pitch and the nominal reduction in radius can determine an attainable straightening ratio of the product, and there exists a minimum length of rollers to guarantee the selected straightening ratio of the product. The curved shape of pipe specimen can be straightened up to 90% under optimum working conditions. It was also found that there exists a maximum pitch to guarantee a certain straitening ratio of the product, and the axial feed rate can be selected arbitrarily in practice.     

圆弧齿轮加工中的对中问题探讨

通过对圆弧齿轮对中方法、加工实例等几个方面的详细分析,论述了圆弧齿轮(包括双圆弧齿轮)滚切加工时滚刀对中对齿轮啮合精度的影响,认为滚刀对中是保证齿轮啮合精度必不可少的手段之一。并对双圆弧齿轮的成形过程提出了自己的见解。     

汽油机曲柄的轧、锻联合成形工艺

对于汽油机曲柄这样的锻件，有较大的圆盘形头部，而杆部细长，从常用的锻件制坯和成形工艺的比较，采用楔横轧制坯，然后预锻、终锻成形是比较理想的工艺方案。本文从生产的实际需要出发，提出了在汽油机曲柄成形中采用轧、锻联合成形工艺，在楔横轧制坯中又引入了组合式楔横轧模具的设计思路。探讨了组合式楔横轧模具的设计方法，使汽油机曲柄的轧、锻联合成形工艺更具实用价值。     

A study on the cold ironing process for the drum clutch with inner gear shapes

This paper describes a 3D FE simulation of the cold ironing process for forming the drum clutch, the main part component of the automatic transmission. The process of the drum clutch with inner gears that was employed in this study consists of 12 steps associated with nine deep drawing processes and three ironing processes to form the inner gear shape. The ironing processes were focused on this study in order to estimate the dimensional accuracy of the inner gear shape according to the process variables such as the punch shape, the approach angle of the punch, and the thickness reduction ratio. A rigid-plastic finite element simulation was applied to analyze the deformation characteristics of the ironing processes and to determine the optimum parameter for selected conditions. Finally, an experiment on the whole drum clutch forming process was carried out to examine the validity of the analytical results and the chosen parameters.     

人字齿轮减速机的安装特性

针对安阳钢铁股份有限公司第四轧钢厂Φ90mm轧管机组主减速机的使用状况,分析了人字齿轮减速机的装配特性。为消除加工、安装误差,根据人字齿轮在正确啮合传动的情况下,由齿轮左右螺旋角产生的轴向力可以抵消这一特点,对其不合理处作了整改,以达到两啮合人字齿轮在传动时自动对中,轴向力趋于零的目的。     

Deformation Machining - A New Hybrid Process

This paper describes a novel hybrid process, Deformation Machining, that combines two emerging manufacturing processes - machining of thin structures and single point incremental forming. This hybrid process enables the creation of structures that have geometries that would be difficult or impossible to create using any other processes. A feasibility study has been conducted exploring the toolpath planning and deformation force data was collected. Because the forming operations occur on sheet-like material made by machining rather than rolling, we have conducted experiments testing the formability of machined sheet. Preliminary results are encouraging, and point to a broad range of industrial applications for this process.     

Investigation of the coating thickness of plasma-transferred arc deposition welded and cross wedge rolled hybrid parts

Most of today’s technical parts and components are made of monolithic materials. These mono-material components produced in established production processes reach their limits due to their respective material characteristics. Thus, a significant increase in production quality and efficiency can only be achieved by combining different materials in one part. Bulk forming of previously joined semi-finished products to net shape hybrid components that consist of two different materials is a promising method to produce parts with locally optimized characteristics. This new production process chain offers a number of advantages compared to conventional manufacturing technologies. Examples are the production of specific load-adapted forged parts with a high level of material utilization, an improvement of the joining zone caused by the following forming process and an easy to implement joining process due to the simple geometries of the semi-finished products. This paper describes the production process of hybrid steel parts, produced by combining a plasma-transferred arc deposition welding process with a subsequent cross wedge rolling process. This innovative process chain enables the production of hybrid parts. To evaluate the developed process chain, coating thickness of the billet is analysed before and after cross wedge rolling. It could be shown, that the forming process leads to an improvement of the coating, meaning a more homogeneous distribution along the main axis.     

Production of integral serrated outside finned tube using a combined method of rolling and wedging/extruding

Most recently, energy and materials savings considerations have stimulated the demand for high efficient and compact heat exchangers. Finned tube is a well-known technology that promotes heat transfer efficiency. This paper proposes a new method of manufacturing integral serrated outside finned tube—rolling and wedging/extruding method. In this method, surface material of workpiece is only split from workpiece body, but not removed. The split and inseparate “chips” can be used to integral outside fins. The wedging/extruding tool is designed. Comparing to conventional cutting tool, the secondary cutting edge is transformed into curve face and only primary cutting edge is remained in wedging/extruding tool. The forming process of integral serrated outside finned tube by rolling and wedging/extruding is analyzed. In addition, the main technical parameters which affect the fins height and pitch are also discussed.     

齿轮精密锻造技术的发展

研究和试验了圆柱直齿轮、圆柱斜齿轮和同步齿轮等 3种汽车用齿轮。制造工艺采用温锻加冷处理 ,用有限元模拟来分析锻造过程和设计模具 ,从而保证齿轮的精度。经过 3年的研究 ,已掌握其基本技术 ,下一步将进行工厂现场试验     

Implementing a high accuracy Multi-Mesh Method for incremental Bulk Metal Forming

The demand for the simulation of incremental bulk forming processes is high. However, the computation times for such simulations are still unsatisfactorily long and thus, their application is deterred. To accelerate the simulations, a multi-mesh algorithm was implemented in the Finite-Element simulation package PEP&LARSTRAN/Shape. This method uses a FE mesh which is fine in the deformation zone and coarse in the remaining areas. A second mesh, fine over the entire volume, is used to store computed values and to minimize the loss of accuracy. The method was tested on an open die forging process and adapted for ring rolling. This paper describes the latest further developments of the method in [1], for instance tool kinematics, remeshing and data transfer and compares its results to conventional models, thereby showing its performance and accuracy.     

基于MATLAB和Pro/E的非圆齿轮设计

针对当前非圆齿轮设计和建模过程繁琐,齿廓特征点提取过程复杂,非圆齿轮设计完成后验证不严谨,以非圆齿轮为研究对象,依据齿轮啮合原理,提出一种简单的非圆齿轮设计方法,并以一个数值算例对该方法进行了验证.此外对非圆齿轮节曲线根切、封闭性和凹凸性进行判断,对弧长进行计算,对非圆齿轮的焦点进行精确的求解.最后,以Pro/E为建模...     

槽的连续局部塑性成形与劈挤

介绍了用于加工槽的各种连续局部塑性成形方法,包括螺纹轧制、横轧与斜轧、分劈、花键轴滚轧、劈分轧制、花键轴/齿轮开模挤压、花键套挤压、槽型换向器整体冷锻、外翅片管挤压—犁削、内/外螺纹管拉拔等。在总结归纳各种方法变形特征的基础上,根据模具工作部分与坯料之间的运动关系,提出槽的连续局部塑性成形可划分为滚轧与劈挤两种基本变形方式。初步给出了劈挤定义,并对几种常见结构槽进行了物理模拟实验验证。初步介绍了劈挤所用模具、变形特征、应用范围。