小模数齿轮单面啮合测量机的研制

小模数齿轮因几何与机械性能的限制,传统的单向驱动式单面啮合测量技术一直未能在其测量中得到应用.针对此问题,提出了"双向驱动"式单面啮合测量新原理,基于该原理研制了小模数齿轮单面啮合测量机.重点介绍齿轮单面啮合测量新原理、测量机的组成及关键技术.在结构设计方面,采用两轴系平行但不在同一端的结构布局,利用两伺服电机同步驱动实现两轴系的主动回转,通过微角度测量装置获取测量齿轮相对其轴系的微转角差,开发无线传输技术进行信号采集.在软件设计方面,基于Microsoft Visual C++6.0开发了小模数齿轮单面啮合测控软件.实际测试表明,该测量机能实现小模数齿轮的快速测量.     

基于系统辨识算法的齿轮传动动态性能研究

将系统辨识方法正确地应用于实际工况下齿轮传动动态性能的研究,通过研究齿轮箱中直齿圆柱齿轮传动周向振动和噪声之间的关系,建立了系统辨识差分方程模型。此模型能够比较准确地描述齿轮传动系统的动态特性,为齿轮传动系统的修形、减振、降噪和优化设计提供了一种新的建模方法,有利于将齿轮传动动态性能的研究成果在实践中推广应用。     

Performance improvement method for Nylon 6 spur gears

Plastic gears made of Nylon 6 are especially susceptible to failure due to extreme heat accumulation in the single tooth mesh area, which results in damage that consequently shortens gear teeth life and causes transmission errors. In this experimental study, the teeth width of plastic spur gears made of Nylon 6 were modified and investigated. The values of load sharing, F/b, in single and double tooth meshing areas were leveled by widening the single tooth zone along the meshing area, and the performances of both modified and unmodified gears were studied experimentally under three different loadings. It was observed that modified Nylon 6 gears exhibit lower tooth temperatures, which results in a decrease in wear rate as compared to unmodified gears. Consequently, teeth width modification helps to increase Nylon 6 gear performance.     

Influence of shot peening on the surface durability of thermomechanically treated En 24 steel spur gears

En steel, in untreated and thermal treated conditions, with and without shot peening, were tested in a back-to-back gear test rig. Their contact fatigue characteristics were studied and S–N curves have been established. Contact fatigue strength of shot peened gears for a given life showed an improvement in relation to unpeened gears.     

考虑齿间载荷分布的齿轮弯曲疲劳寿命估算

考虑齿轮啮合过程中齿间栽荷分布的因素,通过对齿轮原始栽荷历程进行插值修正和雨流计数,运用三维有限元分析方法,探究了齿间栽荷分布对齿轮弯曲疲劳寿命预测的影响。研究结果表明,考虑齿间栽荷分布对齿轮栽荷谱的统计特征有较大影响,并降低了齿轮的弯曲疲劳寿命预测结果。     

HXD1C型大功率机车传动系统齿轮的疲劳可靠性分析

基于标准和可靠性曲线,分析了HXD1C大功率机车传动系统齿轮的接触和齿根弯曲疲劳可靠性。结果表明,按照齿轮标准计算方法,齿轮的啮合接触疲劳强度和齿根抗弯强度合格。基于接触和齿根弯曲疲劳可靠性曲线的分析结果表明,在置信度95％及可靠度0．99下,齿轮的抗弯疲劳强度较弱,寿命321．32万公里;在置信度95％及期望寿命80万公里下,传动齿轮的抗弯疲劳强度仍然较弱,可靠度水平为0．9971。     

多齿轮式齿轮泵的齿轮变位设计

迄今为止,齿轮泵的寿命还远远达不到设计要求,这主要是齿轮泵存在较大的径向不平衡力所致,通过在一个齿轮周围对称布置若干个齿轮构成多齿轮式齿轮泵,就可以实现径向力的平衡,大大延长齿轮泵的服役时间,本文综合运用行星传动机构及齿轮泵的有关知识,分析了多齿轮式齿轮泵的齿轮变位问题,为泵的研究和开发提供了一种创新思路。     

Analysis of micropitting of prototype surface fatigue test gears

The early stages of micropitting were examined on experimental gears designed for surface fatigue studies by the Helical Gear Rating Committee of the American Gear Manufacturers Association. Optical profilometry, scanning electron microscopy, and metallographic examinations were conducted on the first prototype gearset tested. The gearset was tested in an FZG test rig. To evaluate tooth bending fatigue strength, the gears were loaded to load stage 12. A tooth broke from bending fatigue in 0.88 h (the expected time). This short runtime allowed for the examination of micropitting at an early stage of development. The distribution and morphology of micropitting over the tooth face and associated relationships with surface micro‐ and macrogeometry features and traction have been examined. Micropitting was primarily associated with finish geometry. A few pits were associated with sulphide inclusions and one pit was possibly initiated by a small non‐metallic inclusion. Metallographic examinations revealed asperity‐related lines of dark etching alterations caused by high asperity contact and traction stresses.     

双面受载齿轮弯曲疲劳设计方法研究

对现行的齿轮弯曲疲劳设计方法进行了研究，发现现行的方法如果采用按GB／T3480-1983齿轮弯曲疲劳实验方法，得出的数据进行齿轮的弯曲疲劳设计，只适用于齿轮单面受栽的情况。为了解决这一问题，从疲劳损伤的基本理论出发，结合GB／T3480—1983齿轮弯曲疲劳实验方法，推导出了求解齿轮双面受栽弯曲疲劳应力的修正方法和相应的计算公式，对原有的方法进行了补充。     

减速齿轮传动中主动轮齿根弯曲疲劳的计算

传动齿轮强度理论认为,齿间滑动摩擦对齿轮齿根弯曲疲劳的影响可忽略不计。针对此说法,本文作者对带惰轮的起重减速齿轮传动中主动轮受国情况展开全面的分析研究,推导出包括齿间滑动摩擦力在内的,实际外载荷作用下的主动轮齿根弯曲疲劳应力计算公式。结果表明,齿间摩擦力对含惰轮的减速齿轮传动中主动轮齿根弯曲疲劳强度的影响不可忽视。     

Scuffing resistance of salt bath nitrocarburized medium carbon steel

The usefulness of the ferritic nitrocarburizing treatment for improving the tribological properties of ferrous components is well established. However, the thin compound layer of beneficial epsilon carbonitride that develops at the surface lacks the ability to bear high Hertzian stresses. Nitrocarburizing in the austenite phase field of the Fe---N---C system overcomes this disadvantage since the formation of a hard zone of martensite-bainite below the compound layer provides the back-up to withstand point loads. Results of the Falex scuffing test indicate that the failure load increases on account of the thicker compound layer at the surface. The results indicate further that the frictional heat generated during the test coupled with working by the jaws convert the retained austenite present in the sub-compound layer to harder microconstituents. The study suggests that the austenitic treatment could be useful for applications involving simultaneous heat and work such as hot working dies.     

Fatigue strength improvement of gears using cavitation shotless peening

Peening, using cavitation impacts induced by bubble collapse, represents a novel surface enhancement technique for machine parts without involving conventional shot peening blasting. This is known as cavitation shotless peening, CSP. The improvement in the fatigue strength of a spur gear after CSP has been demonstrated. The fatigue strength of a gear treated with CSP was improved by about 60%, compared with that of a non-peened gear.     

Surface integrity studies on shot-peened thermal-treated En 24 steel spur gears

En 24 steel spur gears in untreated and thermal-treated conditions with and without shot peening were tested in a back-to-back gear test rig. Surface finish at the pitch region and wear loss were monitored. Surface integrity studies and ferrographic analysis of wear debris enabled the interpretation of failure. The surface deterioration was less pronounced in the case of shot-peened gears and further they exhibited good steady-state wear characteristics compared to unpeened gears.     

Performance studies of deep cryogenic treated tungsten carbide cutting tool inserts on machining steel

Abstract

Machining studies were conducted on a carbon steel workpiece using both untreated and deep cryogenic treated P-20 tungsten carbide cutting tool inserts. The flank wear of deep cryogenic treated carbide tools is lower than that of untreated carbide tools on machining of C45 steel. The cutting force during machining of C45 steel is lower with the deep cryogenic treated carbide tools when compared with the untreated carbide tools. The surface finish produced on machining the C45 steel workpiece is better with the deep cryogenic treated carbide tools when compared with the untreated carbide tools.     

W18Cr4V钢钛催渗盐浴氮碳共渗工艺研究

试验研究了钛催渗对W18Cr4V钢盐浴氮碳共渗的影响,分别就盐浴处理温度和时间等工艺参数对试样表面性能影响进行了研究。试验结果表明,钛催渗剂的多少对提高共渗层表面硬度具有显著作用,钛催渗可显著缩短盐浴处理时间,有效提高渗层厚度和硬度,能得到质量良好的渗层。     

封闭齿轮传动效率的实验研究

从实验角度出发 ,且理论与实际相结合 ,指出影响封闭齿轮传动效率的因素     

基于ANSYS的锥齿齿轮强度分析

介绍利用ANSYS对锥齿齿轮精确建模的方法和有关程序,并尝试将轮齿通过ANSYS转化成由节点及元素组成的有限元模型.计算分析锥齿齿轮啮合过程中的接触应力,并与赫兹公式计算结果进行比较.结论说明了新的接触单元法的精确性、有效性和可靠性.     

基于设计知识的齿轮参数化模型

将设计知识或规则融入到产品的建模过程中,实现了产品设计的参数和知识驱动。研究了设计知识在建模过程中的表达方式,并在齿轮的建模过程中加以应用。建立了直齿圆柱齿轮、斜齿圆柱齿轮、直齿圆锥齿轮、斜齿圆锥齿轮的统一模型。     

齿轮三维建模方法的误差分析

对齿轮的各种建模方法进行了对比分析,提出一种较为精确、可行的建模方法,对各种建模方法的误差及其对齿轮运动精度的影响进行了探索和对比分析,并就如何在虚拟环境中对虚拟的齿轮进行精度检测,提出一种尝试。     

控制渗碳齿轮磨齿裂纹的工艺措施

以广泛应用的20CrMnTi齿轮钢为研究对象,针对在生产实际中经常出现的磨齿裂纹问题,从磨齿加工、热处理方面探讨了各种因素对产生磨齿裂纹的影响,并提出了控制磨齿裂纹的工艺措施。