高频焊管机辊轮寿命研究

目前高频焊管机运行不稳定，主要是辊轮寿命较低。本文通过分析和实验，提出了提高辊轮寿命的途径和措施。     

辊轮的失效分析

本文介绍了轧管机上辊轮的失效分析过程。分析了辊轮开裂和磨损的原因，并提出了提高辊轮寿命的措施。     

一种圆弧锥辊的全向轮结构及其分析

介绍了一种新型圆弧锥辊全向轮的结构及其设计方法,该全向轮轮缘采用单一的圆弧锥辊排列,圆弧锥辊的大小头相互嵌套,是一种单排连续切换的全向轮。分析了几种典型的全向轮结构及圆弧锥辊全向轮的结构及其设计特点,给出了圆弧锥辊全向轮的锥辊曲面参数方程,根据其结构特点,推导给出了该全向轮结构参数计算公式,并从几何关系和强度两方面分析给出了此种全向轮最佳的锥辊数。      

短类零件滚压成形机设计

详细介绍了短类零件滚压成形中,辊间距大小,辊轮的设计和斜辊技术,并通过链传动实现下辊轮主动,上辊轮被动,上下辊轮节圆不等的成形方法,该技术不仅适用于短类零件的滚压成形,对其它滚压成形设备的设计也具有很大的参考价值。     

造粒机辊轮密封失效原因的分析

分析了密封结构、工作介质、粉体静压力对辊轮组合密封的影响,讨论了组合密封中迷宫密封与唇型密封的失效原因,给出了改进的措施及方法.静压力使得粉体物料进入阶梯型迷宫密封形成堆积,并堆积到唇型密封圈的"唇口"而形成内外压力差,当压力差超过设计压力差时,唇型密封圈失效;工作介质的腐蚀性使密封面、静轴和环型螺旋弹簧严重锈蚀,导致辊轮的密封失效.通过改变阶梯型迷宫密封的结构,增大密封压力,提高密封面、静轴和环型螺旋弹簧的耐蚀性能以及改进布料器的设计等可延长辊轮组合密封的寿命.     

挤压-弯曲一体化成型铝合金弯曲型材的质量与性能

通过改造传统挤压机,增加弯曲装置,对铝合金型材进行挤压-弯曲一体化成型,研究了辊轮半径和辊轮移动速度对成型质量的影响,基于有限元模拟获得了辊轮半径和辊轮移动速度等最佳工艺参数。结果表明:当型材挤出速度与辊轮移动速度相同时,铝合金型材的成型性较好;挤压-弯曲一体化成型工艺避免了传统拉弯工艺存在的回弹、表面划伤和截面变形等缺陷,提高了弯曲型材力学性能的均匀性。     

辊压机煤粉成型力学分析

基于理论与实验相结合的方法,针对实际工况下辊压机辊压区内的力学状态进行研究分析。对煤粉受力与压缩状态进行标定实验,得到煤粉受力与受压后密度之间的公式。基于散体力学相关理论对辊轮进行力学分析,建立辊轮承受扭矩的数学模型并计算辊轮承受扭矩,再进行扭矩实验验证与辊轮电机优选。验证结果表明:辊轮承受扭矩的理论计算值与实验验证值的相对误差为0.45%～3.69%,验证了理论计算的正确性;并且辊轮电机选取15 KW即可满足要求,在降低辊压机生产成本的同时,也为辊压机之后的工作节省了运行成本。     

W6Mo5Cr4V2钢轴承环冷轧芯辊的疲劳断裂与寿命分析

检测W6Mo5Cr4V2钢冷轧芯辊断口的宏观与微观形貌以及芯辊的表面质量与显微组织,并对芯辊的疲劳寿命进行理论分析.结果表明,低寿命冷轧芯辊的疲劳断裂源主要是表面缺陷,高寿命冷轧芯辊的疲劳断裂源主要是亚表层缺陷.冷轧芯辊的表面缺陷减少了疲劳裂纹萌生阶段的寿命,是导致芯辊过早疲劳断裂的主要原因,其对芯辊疲劳寿命的影响程度超过显微组织的影响程度,延长冷轧芯辊疲劳裂纹的萌生寿命是增加芯辊总寿命的主要方向.冷轧芯辊疲劳寿命的分布集中在两个不同的区域.     

基于滚轧技术螺旋锥齿轮的加工方法研究

针对螺旋锥齿轮传统铣削加工材料利用率低、金属纤维流线被切断的缺点,开展滚轧近成形技术研究,提高其抗弯曲疲劳寿命,提升企业加工螺旋锥齿轮的效益。运用共轭曲面原理得到辊轮模型,基于等体原理得到轮坯模型,确立辊轮与坯料之间的运动关系。在DEFORM软件中进行数值模拟,计算成形载荷、最大表面积、所受扭矩、等效应变等物理量。对螺旋锥齿轮的滚轧过程做了试验研究,试验发现滚轧过程中容易出现突耳、折叠、齿形充不满等缺陷,试验表明滚轧近成形是可行的,但滚轧工艺有待改进。     

汽车车窗密封条辊压辊轮的数控加工

通过分析汽车密封条辊压辊轮的加工特点 ,提出采用PCBN刀具以车带磨实现辊轮复杂型面数控加工的工艺方案 ,介绍了辊轮数控加工的程序编制及加工模拟     

矿用牙轮钻头的径向游隙对轴承寿命的影响

建立了适合于牙轮钻头轴承寿命计算的数学模型 ,从理论上阐述了非标准轴承设计径向游隙控制对轴承寿命影响的重要性 ,轴承的径向游隙越大 ,寿命越短。钻头设计要优化轴承结构参数和径向游隙 ,以提高国产牙轮钻头的寿命     

圆锥滚子轴承半凸滚子的优化研究

众所周知,滚子轮廓对圆锥滚子轴承的总体性能有着非常大的影响.在传统的滚子轴承外形尺寸的设计中,常常从轴承的疲劳寿命等方面对其进行分析,但很少同时考虑和分析滚子的动态刚度及疲劳寿命.从轴承的疲劳寿命和刚度特性来看,在现有的滚子类型中,半凸面滚子被认为是最佳的滚子轮廓之一.在对半凸面滚子进行优化设计过程中,重点研究了两个基...     

Effect of Roller Geometry on Roller Bearing Load–Life Relation

Cylindrical roller bearings typically employ roller profile modification to equalize the load distribution, minimize the stress concentration at roller ends, and allow for a small amount of misalignment. The 1947 Lundberg-Palmgren analysis reported an inverse fourth-power relation between load and life for roller bearings with line contact. In 1952, Lundberg and Palmgren changed their load–life exponent to 10/3 for roller bearings, assuming mixed line and point contacts. The effect of the roller–crown profile was reanalyzed in this article to determine the actual load–life relation for modified roller profiles. For uncrowned rollers (line contact), the load–life exponent is p = 4, in agreement with the 1947 Lundberg-Palmgren value, but crowning reduces the value of the exponent, p. The lives of modern roller bearings made from vacuum-processed steels significantly exceed those predicted by the Lundberg-Palmgren theory. The Zaretsky rolling-element bearing life model of 1996 produces a load–life exponent of p = 5 for flat rollers, which is more consistent with test data. For the Zaretsky model with fully crowned rollers, p = 4.3. For an aerospace profile and chamfered rollers, p = 4.6. Using the 1952 Lundberg-Palmgren value p = 10/3, the value incorporated in ANSI/ABMA and ISO bearing standards, can create significant life calculation errors for roller bearings.     

滚动直线导轨副寿命试验方法

针对滚动直线导轨副的寿命问题,对其寿命试验方法进行了研究。介绍了滚动直线导轨副寿命试验装置的组成结构和功能,根据试验装置提出了滚动直线导轨副的恒定应力加速寿命试验方法。在此基础上采用最优线性无偏估计法对试验数据进行了处理。对形状参数和特征寿命的估计值进行了计算和分析。对具体型号的滚动直线导轨副,给出其加速寿命试验方法示例。     

Statistical investigation into the effects of distributed roller diameter error on the fatigue life of tapered roller bearings

This study examined the effect of distributed roller diameter error on the fatigue life of a Tapered roller bearing (TRB). To this end, a comprehensive analysis procedure to perform a statistical analysis of the fatigue life with respect to dimensional error was presented. The roller diameter error was assumed as normally distributed, with a designated mean value and a varying standard deviation. Simulations were conducted to investigate the effects of roller diameter deviation on the fatigue life of the TRB. The numerical results showed that the normally distributed roller diameter error did not necessarily result in a normally distributed bearing fatigue life. The adequate distribution function for the bearing fatigue life with respect to the roller diameter error was explored and found to be dependent on the amount of standard deviation of roller diameter error. The Weibull distribution is appropriate for a small standard deviation, while the gamma distribution and normal distributions are appropriate for large and in-between standard deviations, respectively.

     

滚子修形对轴承性能影响的研究

为了提高滚子轴承的工作寿命和承载能力，普遍采用滚子修形。本文研究了直线滚子、全凸滚子、凸弧－直线滚子和对数滚子的母线方程及修形参数，在相同的工况条件下，分析计算了这四种滚子的接触应力沿接触线的变化情况，得出了对数滚子具有最佳受载状态的结论。并以提高轴承工作寿命为目标，建立了确定最佳修形量的数学模型，分析了修形量对轴承受载特性的影响，得出了滚子合理修形可以显著改善高速滚子轴承受载状态的结论     

滚动直线导轨寿命影响因素研究

通过对影响疲劳寿命诸多因素的分析,建议在以后的计算中可采用修正后的寿命计算公式。并针对各因素,提出了延长寿命的措施。     

Optimization of partially crowned roller profiles for tapered roller bearings

The roller profile plays a key role in the overall performance of roller bearings. In traditional profile design for roller bearings, the roller profile was often analyzed in terms of the bearing performance, particularly the fatigue life. However, the bearing dynamic stiffness and fatigue life were seldom considered simultaneously in the design of Tapered roller bearings (TRBs). Among the available roller profiles, the partially crowned roller profile has been acknowledged as one of the best from the viewpoint of the bearing fatigue life and stiffness characteristics. This paper presented a design optimization for the partially crowned roller profile to improve the performance of TRBs. Two profile parameters of rollers employed for TRBs including the central flat length and crown radius were investigated. The optimal design parameters for the roller profile were obtained in consideration of both bearing fatigue life and stiffness. The proposed design approach was useful and applicable for further geometrical optimization, manufacturing, and engineering application of rolling bearings.     

成型辊装置与受力机理分析

介绍了成型辊装置的结构设计，并对其辊头受力机理进行了分析。揭示了辊形设计的基本思路，为延长成型辊使用寿命给予了参考依据。成型辊的结构和辊形的确定在实际应用中证明简单、合理、可靠、使用寿命长。