高速角接触球轴承系列产品的设计改进

高速角接触球轴承在高速运转设备中的运用越来越广泛。为提升自主创新能力,针对当前使用中存在的相关问题,对高速角接触球轴承进行了设计改进(指接触角为15°或25°的轴承),取得了良好的效果。     

某深沟球轴承保持架断裂分析

某深沟球轴承在使用后出现保持架断裂故障。经对轴承的故障特征、理化分析和尺寸测量后发现,该轴承的钢球直径组差超差,引起接触应力增大以及附加振动载荷,导致滚道疲劳剥落和保持架断裂。     

圆弧砂轮的修整和金刚笔的调整方法

介绍了磨削球轴承沟道用砂轮的修整方法及修整砂轮圆弧所用金刚笔的不同调整方法,对保证和提高球轴承沟道磨削质量和加工效率具有借鉴作用。     

MC6025-MP型断屑槽对车削力影响的试验研究

选用MC6025、UE6020、US735共3种牌号的不同断屑槽型:MP,MA,MS型刀片,采用正交实验法断续干式车削45#钢,通过三向测力仪测定了相同切削用量下不同槽型刀片的切削力。采用回归分析法推导出切削力与切削速度、背吃刀量、进给量的关系表达式,并获得不同槽型刀片对切削力的影响规律,通过极差分析进一步验证了上述结果。同时,试验结果得到了新型刀片MC6025的MP型槽的最适切削参数。分析结果表明:背吃刀量对MC6025-MP型刀片的切削力影响最大,对US735-MS影响最小;切削3要素对切削力影响的一般性结论对不同槽型刀片也是成立的。该实验范围内,新型刀片MC6025-MP的最适切削参数为:ap=0.05 mm,f=0.1 mm/r,v=56.9 m/min。     

目次

为充分了解HFW焊管焊缝沟槽腐蚀机理,及其对高频电阻焊管力学性能的影响,从而探索出有效降低HFW焊管沟槽腐蚀敏感性的方法,从沟槽腐蚀影响规律、测试方法等方面对国内外现阶段沟槽腐蚀研究成果进行分析汇总,着重分析了几种主要的沟槽腐蚀敏感性测试方法,对其优劣性进行了对比。同时,根据沟槽腐蚀研究现状以及相关知识产权的情况,发现目前国内外尚无统一标准的焊缝沟槽腐蚀深度的测量设备或装置,对沟槽腐蚀敏感系数临界值也缺乏工程依据,其失效判定的有效性有待进一步探讨。     

含沟槽缺陷铜镍合金管爆裂压力计算

为了准确评价铜镍合金管存在沟槽缺陷时的爆裂压力,建立了爆裂压力预测公式,进行了爆裂过程的数值模拟,确定了修正函数,进行了静水压爆破试验。数值模拟与试验结果均表明:DNV标准与数值模拟结果误差随腐蚀深度增加先减小后增大,依靠含缺陷深度参数的修正函数建立的预测公式可以有效预测铜镍合金管爆裂压力,试验证明公式准确性较高;对比爆破试验裂口形貌,管道在仅受内压状况下爆裂过程的数值模拟效果较好;管道在剩余壁厚较薄时表现为塑性断裂,剩余壁厚较厚时表现为脆性断裂。爆裂压力的研究可为科学维修舰船管路提供理论依据,对指导管路状态评估有重要意义。     

基于ADAMS大型节筒坡口数控等离子束加工专机仿真

在分析大型节筒坡口数控等离子束加工机床的工作原理的基础上,运用UG软件对大型节筒坡口数控等离子束加工机床进行三维实体建模及装配,并将模型导入虚拟样机分析软件ADAMS中。利用多体系统动力学理论,在ADAMS中给模型施加约束和驱动,对其进行运动学仿真分析,验证了设计的合理性,确保所设计的机械结构能够达到使用要求。     

Non-equilibrium evolution and characteristics of the serrated microchannel hydrogen knudsen compressor

The hydrogen Knudsen compressor has great potential to transport hydrogen and provide the required pressure in MEMS and microfluidic systems. The microchannel composed of cold and hot serrated surfaces is beneficial to the temperature control of the multistage Knudsen compressor. In the present study, a serrated hydrogen Knudsen compressor model is established initially, and the non-equilibrium evolution is numerically studied by using the method of N–S equations with the slip boundary. The key factors affecting the non-equilibrium evolution are comprehensively analyzed. The flow behaviors and performance of the serrated hydrogen Knudsen compressor in different times are studied. It is found that the main factors affecting the non-equilibrium evolution are the thermal expansion flow, thermal transpiration flow, and Poiseuille flow. Meanwhile, the serrated structure affects the local flow in the serrated microchannel at different times. Under the interaction of the thermal transpiration flow and the Poiseuille flow, the pressure difference between the two containers first increases rapidly and then decreases slowly, and finally approaches 1886 Pa. The research reveals the flow mechanisms of the hydrogen Knudsen compressor in the non-equilibrium evolution, which provides theoretical support for the safety and reliability of the hydrogen Knudsen compressor.     

Study of cutting deformation in machining nickel-based alloy Inconel 718

During the process of high-speed machining nickel-based alloy the material presents serrated chips. An experiment involving quick-stop device was conducted. The chip root obtained in the experiment was presented in a metallographic graph. Through the analysis of metallographic graph, the physical features showed that shear angle is reduced and shear plane is converted into shear body when serrated chips formed were analyzed. Conditions under which a crack appeared and adiabatic shear that occurred were also analyzed. Based on the research, shear strain, shear strain rate and shear stress model in the adiabatic shear band were established. The effects of cutting parameters on character of the serrated chip were studied through observing chip metallographic graph.     

义棠煤业巷道底鼓切槽控制技术研究

针对100505工作面回采巷道底鼓的问题,通过建立力学模型,分析了底鼓的成因并提出了切槽卸压防治底鼓的措施,计算出了卸压槽的具体尺寸.利用FLAC3D数值模拟试验,得出了切槽宽度越宽,底鼓控制效果越好的结论,但巷道两帮及顶板变形量增加的特征,结合理论计算及数值模拟结果,确定了巷道切槽最佳尺寸;并在现场进行了工业试验,切槽切槽后150 d巷道最大底鼓量仅为73 mm,底鼓防治效果显著.