低焦油滤嘴烟支总通风率稳定性的研究与应用

在卷烟生产中,接装纸预打孔易堵塞、胶水易渗透到无胶区,导致通风面积缩小,滤嘴烟支总通风率下降,总通风率SD值较高。新型带缓冲有胶区控胶轮的设计与应用,解决了接装纸预打孔受堵,无胶区通风面积减小的问题,提高了低焦油卷烟总通风率的均值,降低总通风率SD值,减少焦油吸入量。     

三叉杆-球笼式万向联轴器组合传动轴系统的动力学仿真研究

为了解三叉杆-球笼式万向联轴器组合传动轴系统的动态特性,为以后的设计工作提供理论依据,对三叉杆-球笼式万向联轴器组合传动轴系统的滑移销、叉杆臂和钢球等关键部件进行了研究。运用ADAMS软件对三叉杆-球笼式万向联轴器组合传动轴系统建立了动力学仿真模型,并对其分别进行了无摩擦和有摩擦条件下的动力学仿真,得到了关键部件的受力曲线图和摩擦力曲线图。研究结果表明,在三叉杆-球笼式万向联轴器组合传动轴系统中,钢球受力曲线的波动和突变最大,说明钢球属于易磨损部件;相比无摩擦时的受力曲线,有摩擦时作用在各个部件上的受力曲线波动变强,更能反映出该三叉杆-球笼式万向联轴器组合传动轴系统的真实受力情况。     

ZJ17生产预打孔卷烟通风率影响因素研究

预打孔卷烟的烟支通风率直接影响到烟支焦油的大小,在卷烟打孔接装纸规格及标准一定的情况下,影响烟支通风率大小的主要原因有打孔接装纸的无胶区宽度、接装纸与胶辊的包角角度、上胶辊与控胶辊之间的间隙、接装纸卷曲器角度等设备因素,综合各影响因素定义了烟支成型尺寸差,通过烟支成型尺寸差可以将设备部件调整对通风率影响规律应用在实际生产过程中,并且具有直观、方便、节省时间等优点。     

外激波摆动活齿变速传动轴承的设计与分析

针对推杆变速传动轴承啮合副易磨损的问题，提出一种用摆动活齿代替移动活齿(推杆)并通过销轴与保持架形成转动副的外激波摆动活齿变速传动轴承。介绍了其结构和传动原理，推导了其内齿圈的齿形方程并分析了外激波器偏心距、外激波器与摆动活齿的中心距、内齿圈齿数对内齿圈齿形的影响，初步确定设计参数。基于SolidWorks建立轴承三维模型，运用Adams对其进行运动学仿真，实现了对该类轴承的优化并验证了设计的正确性。     

YJ29接装机供胶装置控胶辊的改进

YJ29接装机在正常生产过程中,由于所使用的水松纸和乳胶质量差异,影响胶辊对水松纸的涂胶效果,导致接装机烟支搓接异常,致使成品烟支出现漏气、掉嘴、翘边等质量现象。我们在认真分析论证的基础上,将控胶辊的涂胶区加宽,并在涂胶区的两端各设一加深区,来增加胶辊对烟嘴接合部的供胶量,提高了设备对原辅材料的适应性,大大改善烟支的搓接质量,保证了产品质量,降低了材料消耗,提高了设备效率。     

高速动车组轴箱轴承保持架磨损原因分析

针对某高速动车组轴箱轴承易发生温升预警的问题,分析了轴承温度对保持架磨损的影响及保持架磨损对轴承温度的影响。确定保持架磨损原因为轴承温升异常使保持架膨胀,引起保持架和外圈挡边发生全接触,从而导致保持架产生异常磨损。分析认为:在保证轴承使用性能的前提下可适当增大保持架的引导间隙,以减少保持架磨损。     

溶胶站主轴磨损维修及改进措施

针对GMT-600型液压升降式明胶配制罐在生产中出现的主轴传动轴承破损、主轴轴承位短期性磨损等故障,通过分析在操作、维修该设备时所发现的问题,提出了维修方案及改进措施。     

组合钻床主轴及传动轴轴承支承部件的便捷设计

文章在分析组合钻床主轴和传动轴支承结构及力学模型的基础上，给出了一种快速设计轴承部件的方法。     

变速传动轴承结构设计的优化

针对变速传动轴承存在的主要问题,通过研究变速传动轴承的内部结构和传动原理,根据磨损工况,给出了高效低磨的整体结构优化设计原则,不仅对于变速传动轴承,对于采用了推杆活齿机构的各种活齿传动形式的结构设计,均具有一定的指导意义。     

某起重机传动轴匹配及优化设计

为提高十字轴万向节传动轴系布置的准确性和合理性,基于ADAMS虚拟样机技术研究了某起重机传动轴夹角对输入轴轴承的载荷影响,通过ROMAX软件和台架试验对该轴承寿命进行了优化设计及分析验证.结果表明:传动轴夹角会引起附加弯矩,造成轴承偏载,间接增大径向载荷,显著降低轴承寿命;通过轴承宽度加宽、 轴承材料渗碳强化等方式可有...     

On the wear and failure of high speed roller bearings

A laboratory bearing test rig was constructed to study wear and failure mechanisms in high speed roller bearings under different conditions of loading and lubrication. The design of the rig permitted three bearings to be tested simultaneously. A test run of 720 h duration was performed during which wear of the bearings was monitored using ferrography and atomic absorption oil analysis. Wear debris particles collected from the bearings by ferrography were studied with scanning electron microscopy using energy-dispersive X-ray analysis. The results of ferrography were correlated with the metallographic observations made on the worn bearings.It was found that for lightly loaded high speed roller bearings rolling contact fatigue including surface pitting is not a significant wear or failure mechanism. However, misalignment due to shaft deflection above a critical point cannot be tolerated. Wear of high speed engine bearings can successfully be monitored by ferrography but, as the wear condition accelerates, frequent oil sample collections are beneficial.     

变速箱圆柱滚子轴承的设计改进

针对变速箱内第二根轴后端圆柱滚子轴承在使用过程中滚子靠平挡圈外径处的端面磨损严重,造成轴承抱死的现象,分析了轴承过早失效的原因。通过减少滚子的数量,减小平挡圈与垫圈的高度,加大轴向游隙,并对轴承的局部进行了优化,有效地解决了此故障。     

航空发动机主轴轴承失效模式分析

航空发动机圆柱滚子主轴承常常因为工作条件恶劣,发生失效。采用光学显微镜、扫描电镜、能谱仪、X射线光电子能谱等对服役后的圆柱滚子轴承进行失效分析。结果表明:根据失效机制与微观形貌对失效模式,可以将圆柱滚子轴承的失效模式分为8种不同的失效模式,包括划伤和擦伤、打滑蹭伤、压坑凹坑、疲劳剥落、振纹、受热变色、内圈烧伤、保持架镀银层磨损。对打滑蹭伤、烧伤和保持架镀银层磨损等失效模式的轴承进行分析,结果表明:在打滑蹭伤的轴承表面发现O元素,表明打滑蹭伤过程中发生了氧化磨损;在烧伤轴承表面发现了Fe的氧化物FeO和Fe₂O₃,表明轴承在烧伤时温度较高,润滑油膜被破坏,滚子和内圈互相接触发生剧烈磨损;保持架表面银层脱落,部分磨损区域露出铜表面,表明保持架在服役过程中发生了摩擦磨损。     

Relating contact conditions to abrasive wear

Damage caused by particles within rolling/sliding contacts can severely reduce the operational life of machinery such as roller bearings, gears and pumps.Abrasive wear of spherical roller thrust bearings has been studied using a stylus apparatus and scanning electron microscopy (SEM). Both a standard bearing and a bearing with rollers coated with metal mixed amorphous carbon (Me-C:H) were studied. The SEM measurements were performed systematically across the contact surfaces so that surfaces with gradually different contact situations could be examined. These measurements were compared to the measured wear depth of the components of the roller bearing. Also, the calculated contact conditions in terms of creep, contact size and surface separation have been related to the observed wear pattern at various locations.To attempt to understand the wear behaviour of the bearing with coated rollers, the coating as well as the material content of the surfaces were examined using both SEM and energy dispersive X-ray spectrometry (EDS). This revealed that the coating did not flake off but rather was scratched off.It is possible to link the abrasive wear behaviour to the contact conditions. It is crucial to understand this relationship when building a simulation model of abrasive wear.     

Adaptive finite element simulation of wear evolution in radial sliding bearings

This article employs an adaptive wear modeling method to study the wear progress in radial sliding bearings contacting with a rotary shaft. Mixed Lagrangian–Eulerian formulation has been used to simulate the contact condition between the bearing and the shaft, and the local wear evolution is modeled using the Archard equation. In the developed wear processor algorithm, not only remeshing is performed on the contact elements, but also is executed for their proximity elements. In this way the wear simulation becomes independent of the size of the contact elements. Validation was done for a laminated polymeric composite bearing. The composite has been modeled as a linear orthotropic material. The wear coefficients were obtained from flat-on-flat experiments and were applied as pressure and velocity dependent parameters in the wear processor. Finally, the effect of the clearance on the wear of the radial bearings has been studied numerically. The simulations also demonstrate how the contact pressure evolves during the wear process, and how the clearance influences this evolution.     

滚动轴承保持器磨损对轴承失效的影响

针对滚动轴承运行特点,采用XRF技术调查和分析铜、铁及尼龙为主体材料的保持器在脂润滑条件下的磨损,研究保持器磨损与轴承滚动体磨损之间的相关性及对轴承磨损失效过程的影响,并对不同材料保持器所产生的磨损颗粒对轴承及润滑脂的影响进行初步分析和探讨。统计数据分析结果表明,不同结构或材料构成的保持器在脂润滑轴承运转过程中始终存在着一定程度的磨损,且与轴承滚动体的磨损在磨损相对数量上显著相关;高聚物尼龙保持器所形成的磨损颗粒的影响,更多地反映为保持器材料中硬质填料的机械作用,而钢制保持器因其磨损颗粒具有金属活性和催化性,磨损颗粒同时还加速润滑脂的化学氧化过程及对脂稠化剂网状结构的破坏。     

An Analytical Method to Predict Skidding in High Speed Roller Bearings

Skidding which occurs in high speed roller bearings frequently causes wear and incipient failure of bearing inner ring and roller surfaces. To eliminate skidding, aircraft gas turbine designers, historically, have employed out-of-round outer rings and other preloading devices. Prior to testing of the full-scale bearings at engine speeds, however, the designers have not, heretofore, been able to determine (a) the extent of skidding which occurs and (b) the effectiveness of means employed to eliminate skidding. The analytical method which is presented by this discussion is based upon recently developed elastohydrodynamic lubrication theory and can be used in lieu of expensive testing procedures to adequately predict bearing cage speed, and therefore the extent of skidding, under any condition of radial load and shaft speed. Moreover, the analysis can be used to determine how much radial preloading or outer ring out-of-roundness is necessary to minimize skidding.

The analytical data of this study are compared against experimental data to establish the adequacy of the analysis.     

双列圆锥滚子轴承支承的车辆驱动桥主减速器轴系固有特性分析

车辆驱动桥主动轴采用双列圆锥滚子轴承的支承结构将引起轴系固有特性发生变化,基于赫兹接触及有限元理论建立了双列圆锥滚子轴承刚度模型及支承轴系动力学模型,对比分析了支承结构改变前后的轴系固有特性及轴向载荷对轴系固有特性的影响.分析结果表明:采用双列圆锥滚子轴承支承结构后,减速器主动轴的轴系固有频率较原支承结构有所减小;随着...     

Tribological study of elastomeric bearings for marine propeller shaft system

Elastomeric compounds, due to their favourable properties like sufficient hardness, toughness and natural resistance to abrasion and corrosion, are commonly used as bearing material for propeller shaft system of Indian Coast Guard Ships. Recently unequal and non-uniform wear of these bearings has resulted in unscheduled lay off of the Coast Guard Ships. To solve this problem of bearing wear, a mixed lubrication analysis of sea-water lubricated journal bearing has been attempted in the present study. A computer code was written to estimate lubricating film thickness for a given set of load and speed condition, and to predict the lubrication regime for the specified surface roughness parameters. To validate the theoretical analysis performed in the present study, the results obtained from the computer simulation have been compared with the established studies on the water lubricated bearing.To understand the uneven wear of marine bearings, actual geometric clearances of new and worn out bearings recorded by the ship maintenance team, and the operational data (load, speed and operating hours), obtained from the log books of ICGS Sangram (AOPV) of Indian Coast Guard, are listed in the present paper. The dynamic viscosity of sea water, surface roughness of propeller shaft and bearings, and particulate contamination has been measured. Finally, the suggestions have been enlisted for proper operation of shaft-bearing system so as to maintain the wear within the permissible limits during ship's operational cycle.     

水泵轴连轴承的常见失效形式与改进

水泵轴连轴承失效形式主要为:心轴断裂,心轴滚动表面、外圈沟(滚)道表面、滚动体表面的磨损和疲劳剥落及密封失效。针对其主要失效形式,对轴承的内部几何形状及保持架和密封结构进行了改进。