齿轮强化喷丸在岸边集装箱起重机齿轮箱中的应用

以岸桥集装箱起重机齿轮箱中各级齿轮为研究对象,介绍了一种利用高频疲劳试验机,对喷丸和未喷丸渗碳淬火齿轮做脉动试验的方法,得出各试验齿轮的弯曲疲劳强度及存活率、应力、寿命曲线,通过弯曲疲劳强度试验对比,以验证实施强化喷丸处理。     

Effect of surface treatments on the strength of carburized gears

This paper deals with effects of surface treatment on the bending fatigue strength of SCM415 carburized spur gears. The test gears are treated by the combination of shot peening, chemical polishing and electropolishing after carburization. The fatigue tests demonstrate that the strength is sensitive to the surface condition of tooth fillet and the removal of the nonmartensitic layer caused by decarburization is considerably effective in enhancing the strength. In the first part of this paper, the influence of surface treatments such as shot peening, chemical polishing and electropolishing on the strength enbancement for carburized gears are summarized and discussed. In the second part, the crack lengths are calculated from the fatigue test results for the carburized and surface-treated gears, and the effect of surface treatments is discussed from the view point of fracture mechanics.     

强力喷丸对提高碳氮共渗齿轮接触疲劳强度的研究

通过对碳氮共渗齿轮试片进行了多次强力喷丸试验．研究了不同喷丸参数下的强力喷丸的效果及喷丸后的低温回火处理对提高齿轮试片表面接触疲劳强度的影响。为强力喷丸工艺更好地应用于工业生产提供了一些参考。     

喷丸处理对汽车变速箱齿轮疲劳强度影响的研究

分析了汽车变速箱齿轮经喷丸处理后对疲劳强度的影响，通过喷丸强度试验，表面覆盖率试验确定了合理的喷丸处理工艺，通过疲劳试验，得出了喷丸处理对弯曲疲劳强度和接触疲劳强度的影响程度。结果表明：喷丸处理能极大地提高齿轮的疲劳强度，从而提高齿轮的使用寿命。     

残余应力对齿轮弯曲疲劳的量化影响研究

随着风电、高铁、掘进等高端装备对齿轮功率密度、服役寿命等要求的提高,齿轮的弯曲疲劳问题日益显著。为提升齿轮弯曲疲劳性能,通过渗碳热处理、喷丸强化等工艺为齿轮引入较高的残余压应力已逐渐成为工业界的标配。为揭示残余应力对齿轮弯曲疲劳性能的量化影响,在最大主应变寿命预测准则中引入残余应力影响项,通过弯曲疲劳试验确定最优残余应力影响系数,进而采用新的试验数据验证模型的准确性。基于工程应用出发,引入修正应力的概念统一不同残余应力状态下的齿轮弯曲应力-寿命(S-N)曲线,研究结果显示,最大主应变准则中,残余应力影响系数取值为0.15时,可实现较高的寿命预测精度,而修正的S-N曲线中,最佳残余应力影响系数为0.25。研究成果可用于工程实际中齿轮弯曲疲劳快速评估。     

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。     

Evaluation of surface fatigue performance of gear oils

The effect of additive chemistry on the surface fatigue of gears was investigated using an FZG gear tester and fluids based on an API GL-5 grade gear oil. Surface fatigue lives were determined as a function of load and additive chemistry. At 1.52 GPa, the removal of the primary extreme pressure (EP) additive from the fully formulated gear oil decreased the fatigue life of gears slightly (4%). However, the removal of the primary antiwear (AW) additive decreased the fatigue life of gears significantly (83%). At 1.86 GPa, the removal of the EP additive from the fully formulated gear oil decreased the gear fatigue life by 27%. However, the removal of the primary AW additive decreased the fatigue life of gears significantly (75%). Micro-pitting was the dominant surface morphology in the dedendum of the gears tested with two oils at load stage eleven: one using the complete additive package, and a second where the EP additive had been removed. However, spalling was the primary failure mode of gears tested without an AW additive, independent of whether an EP agent was present. Surface analysis of the pinion gears showed the formation of a mixed phosphate/phosphite—oxide layer on the surface of gears tested with fluids containing an AW additive. Formation of this layer seems to be the key to a long fatigue life.     

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。     

激光淬火齿轮的疲劳寿命和耐磨性机理分析

激光淬火齿轮的疲劳寿命试验研究结果表明，激光淬火齿轮疲劳寿命大大高于常规淬火齿轮，同时还具有很高的耐磨性、抗疲劳折断以及抗剥落性能。本文在试验研究的基础上，分析了激光淬火齿轮具有高疲劳寿命和耐磨性的机理，以及激光淬火齿轮疲劳寿命大大高于常规淬火的原因。     

考虑残余应力的螺旋锥齿轮接触疲劳裂纹萌生-扩展寿命计算方法研究

考虑渗碳、磨齿、喷丸等工艺产生的齿面残余应力,建立齿面接触应力与残余应力的复合应力场,提出一种螺旋锥齿轮接触疲劳裂纹萌生-扩展寿命计算方法。构建齿轮有限元接触分析模型,计算多轴交变接触应力场。考虑空间螺旋曲面残余应力分布的复杂性,将变曲率齿面离散为网状节点;测量各节点表面与次表面的残余应力,建立齿面残余应力场。基于Dang Van多轴疲劳准则,构建齿面裂纹萌生模型;计及残余应力与裂纹闭合效应,构建齿面裂纹扩展模型。计算复合应力场下齿轮接触疲劳寿命,研究残余应力对齿面裂纹萌生-扩展寿命的影响规律。结果发现：复杂齿面空间变曲率会影响喷丸等工艺产生的残余应力分布,中心区域的残余压应力高出齿面边缘区域约20%;复合应力场下齿面裂纹萌生位置与寿命主要取决于接触应力,残余应力会改变齿面节点平均应力进而影响疲劳寿命;齿面裂纹扩展寿命约占全寿命的10%,表征齿轮接触疲劳快速失效至迅速断裂。上述研究对于高性能齿轮传动的长寿命、高可靠性设计具有一定的参考价值。     

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.     

喷丸强化残余应力对疲劳性能和变形控制影响研究进展

作为机械表面强化技术之一,喷丸强化使工件表层发生形变硬化,引入较高的残余压应力,减少了疲劳应力作用下微裂纹的萌生并抑制其扩展,从而显著提高零件的抗疲劳断裂和抗应力腐蚀开裂的能力。基于喷丸残余应力解析计算模型,从余弦函数模型、接触应力模型和球腔膨胀模型三个方面介绍喷丸强化残余应力的产生,进而对喷丸残余应力的仿真预测及影响规律进行论述。为了提高试件疲劳强度而引入的残余压应力会带来影响形位精度的变形,基于此阐述了喷丸残余应力对疲劳性能的影响及其在疲劳过程中的演化,同时论述了喷丸残余应力变形预测及控制的研究现状,最后对喷丸残余应力未来的研究内容与发展方向进行展望。     

轿车变速箱齿轮磨合次数对疲劳寿命影响的试验研究

为了使相同尺寸规格的变速箱满足不同型号车辆对变速箱强度的不同要求，也为了合理设置变速箱齿轮的磨合次数，以达到最佳强化效果，对某型轿车变速齿轮的磨合次数进行初步研究。在试验的基础上，给出该变速箱齿轮低载强化的最佳磨合次数，并总结出该齿轮在交变载荷下不同磨合次数的疲劳寿命增长规律。有助于提高轿车变速箱齿轮的疲劳寿命，也为进一步制定轿车变速箱齿轮的磨合规范提供技术依据。     

高速动车组斜齿轮的齿根裂纹萌生寿命数值计算

为分析高速动车组斜齿轮的齿根裂纹萌生寿命,采用UG建模软件建立了斜齿轮副的三维模型,并通过ABAQUS软件确定了裂纹萌生位置。基于疲劳损伤累积理论,对试验齿轮分别采用名义应力法和局部应力应变法模拟计算出裂纹萌生寿命;进行了高频疲劳试验,得到了裂纹萌生寿命,通过对比模拟结果与试验结果,确定了最佳损伤模型,计算得出了斜齿轮齿根的裂纹萌生寿命。分析了载荷、表面粗糙度、残余应力、齿顶修缘等因素对裂纹萌生寿命的影响规律。研究结果表明,载荷及表面粗糙度对裂纹萌生寿命的影响比较显著;裂纹萌生寿命随着残余压应力的增大而延长;适当的修形可延长斜齿轮裂纹萌生寿命。     

Surface durability of powder-forged roller treated by shot peening

To investigate the influence of shot peening on the surface durability of powder-forged rollers, the case-hardened powder-forged rollers with a forging density of 7.5 g/cm³ treated by the single shot peening and the double shot peening were fatigue-tested under a sliding-rolling contact condition. The surface roughness, the surface hardness and the surface compressive residual stress of the rollers were increased by the shot peening. In addition, the pores near the roller surface were deformed by the shot peening. The failure mode of all the test rollers was spalling due to subsurface cracking. The fatigue lives of all the test rollers were improved by the shot peening, and that of the test roller S08, which was shot-peened with the hardest steel shots in this experimental range, was especially improved. The surface durability of the test roller S08 was also most improved by the shot peening. Cracks became difficult to occur and propagate under the roller surface since the pores near the roller surface were deformed by the stronger shot peening. In this study, double shot peening, which generally restrains the increase in surface roughness, was not particularly effective for the improvement in the surface durability of the powder-forged rollers, because the influence of tangential force on fatigue was not always great in a case of subsurface cracking.     

Influence of lubricants on the pitting fatigue of gears

Using the FZG gear tester with heat-treated and case-hardened gears the effect of lubricants and additives on the incidence of pitting fatigue was investigated. The influence of base oil type and additives requires further investigation before general conclusions can be derived. From the results now available extreme pressure additives which increase the scuffing load carrying capacity of case-hardened gears allow increased load testing without surface pitting failure. Additives have a direct beneficial influence on retarding the pitting of heat-treated gears. Of the additives tested, the most effective in reducing pitting fatigue failure was MoS₂, but with a high concentration of about 1.5%.     

装配参数对附件机匣锥齿轮破裂故障的影响

针对航空发动机附件机匣锥齿轮由装配偏差引起的破裂故障,采用行波共振原理和有限元法,对锥齿轮进行模态分析和静应力计算,分析了啮合锥齿轮的齿轮间隙和主动锥齿轮垂直安装角度对主动锥齿轮齿根应力的影响。仿真与试验结果分析表明：主动锥齿轮结构具有一节径和二节径振型,模态频率与试验误差小于2.5%;齿轮装配间隙对齿根应力影响较小,装配工艺的要求相对合理;主动锥齿轮安装角度偏差对齿根应力影响较大,因此需要严格控制角度偏差。主动锥齿轮断齿金相组织形态及其破裂特征分析表明,锥齿轮的破裂类型为疲劳断裂,断口具有节径型振动疲劳断裂特征。     

减速机齿轮断裂失效分析

某搅拌器减速机齿轮轴和齿轮在服役1 a后发生了断裂失效;通过显微组织分析、断口分析、力学性能测试等方法对其失效原因进行了分析。结果表明:轴和齿轮的断裂均为疲劳断裂,轴的断裂先于齿轮的断裂;搅拌轴装配不当造成的过载是导致轴首先产生疲劳断裂的原因。     

弹丸束喷丸有限元模型数值模拟及试验研究

喷丸工艺是一种有效提高工件表面疲劳抗力的表面处理工艺,被广泛应用在航空、汽车、动力机械等重要领域。喷丸数值模拟是制订喷丸工艺方案、评估喷丸后工件表面疲劳抗力的主要理论工具。目前,现有的喷丸数值模型主要有单弹丸模型、阵列弹丸模型等形式,在这些模型中,弹丸的撞击位置是固定的,忽略了真实的喷丸过程中弹丸位置的随机性。采用有限元计算软件ABAQUS提供的python语言开发一种弹丸在空间位置随机分布的弹丸束喷丸模型,在此模型基础上研究喷丸工艺参数与残余应力间的分布规律,进一步讨论喷丸工艺对工件表面粗糙度的影响,模拟喷丸强度的饱和过程,并通过Q235钢喷丸试验对弹丸束喷丸模型进行验证,为喷丸工艺的精确控制提供了科学依据和理论基础。     

Ferrography as a Health Monitor and a Design Aid for the Development of Helicopter Gearboxes

The use of ferrography to monitor the health of helicopter gearboxes undergoing fatigue substantiation trials is described. The results illustrate the sensitivity of ferrography in detecting the onset of gear fatigue and indicate that the fatigue was initiated by micropitting. This suggests that the gears were not properly lubricated under the fatigue loads.