一种蜗杆─行星轮自动定位机构的设计

分析了采用蜗杆─行星轮机构实现包装过程中自动定位的基本原理，给出了传动机构的设计方法和结构简图，为自动定位机构的设计提供了参考实例。

蜗杆轮注射模的设计

图1为仪表示数装置中的一个蜗杆轮,材料为聚甲醛。模具使用15克立式注射机。注塑件一模出二,机动脱模。

硬齿面蜗杆珩磨轮珩齿工艺及其装备

蜗杆珩磨轮珩齿工艺是八十年代中末期在国内兴起的热处理后精加工齿面工艺。对于中硬齿面的珩磨,已有几家工厂成功应用,但对于硬齿面的珩磨,特别是外径定心花键孔硬齿面齿轮的珩磨加工。还未曾见过介绍。我厂针对用户对齿轮精度要求日益提高的趋势,为寻求稳定加工,按GB10095—88规定的8级精度齿轮的高效、经济加工途径,选择蜗杆珩齿工艺对热处理后硬齿面加工。经过几年的实践,取得良好成效。 一、工艺流程 硬齿面齿轮材料多为20CrMnTi,渗碳淬火达到表面硬度HRC58～64。对于外径定心花键孔齿轮,且有拨叉槽的,如图1所示。由于其截面的变化较大,使孔变形也较大。虽采用稀土碳共渗、碳氮共渗、微氮中温渗碳及栏具定置保护等热处理手段,变形仍不可避免。

发动机拆装翻转架的设计与传动部位分析

为方便研究发动机故障诊断问题,发动机拆装翻转架的设计进行了整体架构设计。对拆装翻转架关键结构:涡轮轴和蜗轮蜗杆传动部位分别进行设计计算和校核,并结合ANSYS—workbench进行了有限元分析模拟,结果表明,所涉及的发动机拆装翻转架关键部位性能便捷可靠,满足设计要求。

Efficient and accurate worm grinding of spur face gears according to an advanced geometrical analysis and a closed-loop manufacturing process

Worm grinding has been applied to manufacture gears to pursue high accuracy and fine surface finish.When the worm used to grind face gears is manufactured with multi-axis computer numerical control(CNC)machining,the machining accuracy is usually improved by increasing the number of tool paths with more time cost.Differently,this work proposes a generated method to improve the efficiency by dressing the worm surface with only one path,and a closed-loop manufacturing process is applied to ensure the machining accuracy.According to an advanced geometric analysis,the worm surface is practically approximated as a swept surface generated by a planar curve.Meanwhile,this curve is applied as the profile of a dressing wheel,which is used to dress the worm surface.The practical machining is carried out in a CNC machine tool,which was originally used to grind helical gears.Finally,a closed-loop manufacturing process including machining,measurement,and modification is proposed to compensate the machining errors.The proposed method is validated with simulations and practical experiments.

New method for calculating face gear tooth surface involving worm wheel installation errors

The machining principle and realization method for the continuous generative grinding face gear by a worm wheel are introduced. Based on a five-axis linked CNC grinding machine, a new method is presented to deprive the equation of face gear error tooth surface by assuming the tool surface as the error surface, where actual tool installation position error is introduced into the equation of virtual shaper cutter. Surface equations and 3-D models for the face gear and the worm wheel involving four kinds of tool installation errors are established. When compared, the face gear tooth surface machined in VERICUT software for simulation based on this new method and the one obtained based on real process(grinding face gear by using a theoretical worm wheel with actual position errors) are found to be coincident, which proves the validity and feasibility of this new method. By using mesh planning for the rotating projection plane of the face gear work tooth surface, the deviation values of the tooth surface and the difference surface are acquired, and the influence of four kinds of errors on the face gear tooth surface is analyzed. Accordingly, this work provides a theoretical reference for assembly craft of worm wheel, improvement of face gear machining accuracy and modification of error tooth surface.

Integrity of grinding face-gear with worm wheel

Aiming at the issue of the grinding integrity of face-gear with worm wheel, the envelope mathematical model of shaper, worm wheel and face-gear is established based on theories of differential geometry and gear mesh. The judgment of completely grinding the face-gear with the avoidance of singularities is established, and the mathematical expression to show the reason why singularities appear is derived, through the research on the surface contact area and singularity rules of the worm thread surface. The disadvantage of current face-gear grinding method that only part of the working surface of the face-gear can be covered is analyzed and the influence of coefficient of judgment is studied through changing the design parameters.

A precision generating hobbing method for face gear with assembly spherical hob

In order to improve the processing precision and shorten the hob manufacturing cycle of the face gear,a precision generating hobbing method for face gear with the assembly spherical hob is proposed.Firstly,the evolution of the cylindrical gear to spherical hob basic worm is analyzed,then the spherical hob basic worm is designed,thus the basic worm and spiral angle equation of spherical hob are obtained.Secondly,based on the design method of the existing hob,the development method of the assembly spherical hob is analyzed,the cutter tooth and the cutter substrate of the assembly hob are designed,and the whole assembly is finished.Thirdly,based on the need of face gear hobbing,a numerical control machine for gear hobbing is developed,and the equation of the face gear is obtained.Fourth,for reducing the face gear processing errors induced by equivalent installation errors,the error analysis model is established and the impacts of each error on the gear tooth surface are analyzed.Finally,the assembly spherical hob is manufactured and the gear hobbing test is completed.According to the measurement results,the processing parameters of face gear hobbing are modified,and the deviation of tooth surface is significantly reduced.