沟槽结构对水润滑轴承润滑特性影响机制

为了研究沟槽结构对船用水润滑轴承润滑特性的影响机制，采用有限元法，通过对简化后的椭圆形沟槽的二维模型进行流体动力学CFD分析，从迹线以及涡流等方面分析沟槽结构参数对沟槽内部流体特征的影响，得到不同状态下沟槽内部的压力轮廓，并分析沟槽结构参数对水润滑轴承摩擦因数的影响和轴承的润滑机制。结果表明：沟槽的大小影响轴承间隙内流体的流通面积，沟槽的结构特征影响沟槽内的流体黏度。研究结果可为水润滑轴承优化设计提供参考。     

基于正交实验法的水润滑轴承结构参数优化设计

建立了8直槽水润滑轴承的数值模型，以偏心率、半径间隙、沟槽数量为影响因素，以摩擦因数、承载力为目标函数，进行正交试验，对水润滑轴承进行优化设计分析，结果表明：增大偏心率、减小轴承间隙、减少沟槽数量有助于降低摩擦因数与提高承载力。     

凹槽缺陷对径向轴承润滑影响的模拟研究

径向轴承在运行过程中由于磨损、疲劳裂纹、烧蚀、开有油槽等,可能会出现沟槽缺陷而影响轴承的润滑状态。基于Reynolds方程对表面有沟槽的径向轴承进行理论建模并进行数值模拟,得到表面有凹槽缺陷的径向轴承在润滑过程中油膜厚度、压力的分布,研究不同形状、周向宽度、深度和周向间距的凹槽对轴承润滑状态的影响。研究结果表明,矩形凹槽对轴承润滑的影响最大;凹槽参数对轴承润滑的影响在润滑油入口区和出口区各不相同,在润滑油入口区,随着凹槽周向宽度、周向间距的增加,承载力减小、摩擦因数增大;在润滑油出口区,随着凹槽周向宽度、周向间距的增加,承载力增大、摩擦因数减小;在润滑油出口区,凹槽深度对轴承润滑影响不大,而在润滑油入口区,凹槽深度增加将导致承载力减小、摩擦因数增大。     

水润滑橡胶轴承特性仿真与试验研究

为研究水润滑橡胶轴承特性,采用软件仿真与试验相结合的方法对轴承偏心率、摩擦因数、橡胶变形量、最小水膜厚度、长径比和水膜压力等参数及其与轴转速和载荷之间的关系进行深入探讨。应用Pro/E软件分别建立了轴承及其间隙的3D模型,并采用流固耦合方法及气穴模型在ANSYS和Fluent软件中对轴承动态特性进行模拟。为获得实际工况下的橡胶轴承径向截面全周连续水膜压力分布,研究轴承润滑状态,采用特殊的转轴设计,将压力传感器安装在轴端,并应用无线测试技术对水膜压力信号进行采集与传输。给出水润滑轴承试验台、转轴设计与传感器布置方案,最后应用无线测试系统对八纵向沟槽水润滑凹面橡胶轴承的水膜压力进行测试,并与仿真结果比较分析。研究结果表明,多沟槽凹面橡胶轴承不存在全周完全连续水膜,处于混合润滑状态;沟槽对水膜压力分布的影响较大;轴承某些板条上会出现水囊,形成明显的压力双峰;降低转速或者增加载荷都会增大橡胶变形量与轴承摩擦因数,引起轴与轴承接触。长径比越大,轴承越不容易与轴发生接触。     

进水温度对水润滑轴承润滑特性的影响

为研究进水温度变化对水润滑轴承润滑特性的影响,采用有限差分法建立水润滑轴承弹流润滑模型,分析不同进水温度和载荷条件下水润滑轴承润滑特性的差异,并且通过试验验证摩擦因数的变化规律。研究发现：随着进水温度升高,轴承的水膜压力下降,但在水膜压力峰区域最大水膜压力升高、最小水膜厚度减小、偏心率增大,表明进水温度升高对润滑性能有着负面影响;在相同的载荷和转速下,轴承摩擦因数随着进水温度升高而下降,且高载荷下进水温度对摩擦因数的影响更大。通过试验发现进水温度越高对摩擦因数变化的影响越大,不同进水温度下载荷越低,载荷的变化对摩擦因数变化量的影响越大。     

水润滑橡胶轴承的制备及摩擦磨损性能研究

以丁腈橡胶(NBR)为基体,制备水滑润橡胶轴承;研究填料、载荷、转速、润滑介质、NBR品种等因素对橡胶轴承在水润滑介质中的摩擦磨损性能的影响,并分析其摩擦和磨损机制。结果表明,炭黑量和二硫化钼添加量明显影响橡胶轴承的摩擦因数和磨损量;随着载荷的增大,橡胶轴承的摩擦因数和磨损量均呈现先增大后减小再明显增大的趋势;随着转速的增大,橡胶轴承的摩擦因数和磨损量均明显减小,并且在海水中的摩擦因数和磨损量均大于在淡水中的摩擦因数和磨损量。     

水润滑橡胶轴承摩擦磨损性能的研究

以丁腈橡胶（ＮＢＲ） 为基体,制备水滑润橡胶轴承;研究填料、载荷、转速、润滑介质、ＮＢＲ品种等因素 对橡胶轴承在水润滑介质中的摩擦磨损性能的影响,并分析其摩擦和磨损机制。结果表明,炭黑量和二硫化钼添加量明 显影响橡胶轴承的摩擦因数和磨损量;随着载荷的增大,橡胶轴承的摩擦因数和磨损量均呈现先增大后减小再明显增大 的趋势;随着转速的增大,橡胶轴承的摩擦因数和磨损量均明显减小,并且在海水中的摩擦因数和磨损量均大于在淡水 中的摩擦因数和磨损量。     

轴颈表面粗糙度对橡胶材料干摩擦特性的影响

当船舶艉轴承供水系统出现故障或轴承过载时,金属轴颈与橡胶轴承之间会发生局部接触而处于干摩擦状态下。为研究金属轴颈表面粗糙度对水润滑橡胶轴承干摩擦特性的影响,采用TIME3230表面粗糙度测量仪对金属轴颈表面微凸体进行测量,得到金属轴颈表面微凸体的位置参数分布曲线,并对其进行去噪处理;利用傅立叶变换重新构造去噪后的金属轴颈表面粗糙度分布,并依据理论计算金属轴颈-橡胶轴承摩擦副的摩擦因数。金属轴颈-橡胶轴承摩擦副的摩擦因数计算结果与实际情况吻合,说明建立的轴颈表面粗糙度分布模型合理。分析结果表明:在干摩擦状态下,金属轴颈-橡胶轴承摩擦副的摩擦因数随着表面粗糙度函数波幅的增大呈线性增大趋势,随着粗糙度分布函数的特征波长系数的增大呈非线性增大;润滑流动方向顺着加工纹理方向时,摩擦因数比垂直加工纹理方向和与加工纹理呈45°时的摩擦因数都小。因此,选择合理的轴承表面粗糙度的幅值和波长可以提高金属轴颈-橡胶轴承摩擦副的摩擦润滑性能;沿加工纹理加工、装配金属轴颈-橡胶轴承摩擦副,可降低摩擦因数。     

复合材料水润滑艉轴承结构设计研究

基于ANSYS CFX流固耦合数值计算方法,对水润滑复合材料艉轴承的润滑性能及结构设计开展研究,阐述了不同水槽结构、间隙比、长径比、直径等对轴承承载力以及水膜压力、轴承变形量、最小水膜厚度、轴承摩擦因数的影响规律。并利用水润滑轴承试验台研究了不同水槽结构对轴承启动摩擦转矩、转变速度以及摩擦因数的影响。研究表明,轴承摩擦因数、水膜最大压强、轴承最大变形随水槽数增多而增大;轴承承载力、最小水膜厚度随间隙比增大而减小,随长径比增大而增大。总结了直径为100~500 mm、长径比为2~3、间隙比为0.1%~0.2%的水润滑艉轴承承载力的变化规律,为水润滑艉轴承设计提供一定的理论依据。     

ANCO水润滑高分子轴承摩擦性能的研究

采用MPV-50试验台架对ANCO水润滑轴承系统地研究了载荷、线速度、水温、润滑介质等因素,对ANCO水润滑轴承的摩擦磨损性能的影响。研究结果表明,ANCO水润滑轴承具有较低的水润滑摩擦因数和较高的耐磨性能,完全适合作为船舶艉/舵轴承使用。     

A study on the effect of surface topography on rough friction in roller contact

The friction behaviour of gear teeth in the context of tribology can have a strong effect on housing vibration, noise and efficiency. One of the parameters that greatly influences the friction under certain running conditions is surface roughness. In this work, rough friction was studied in lubricated sliding of roller surfaces, which were manufactured to simulate the real gear surfaces. By examining 3D surface topography of two mating bodies, both surface roughness and its effect on friction behaviour can be studied. In a previous study, a rough-friction test rig has been designed, constructed and initially verified. The types of surfaces involved in this study are ground, shot-peened, phosphated and electrochemically deburred. These rollers were subjected to the same friction testing procedures. Roller surfaces were then examined, and correlation between the topography and the frictional behaviour was analysed. Friction behaviour was interpreted in terms of Stribeck curves (friction coefficient as the function of Hersey parameter (ην/p)). The results showed that electrochemically deburred and certain phosphated surfaces provide lower friction coefficient values which are competitive to fine-ground surfaces in lubricated rolling/sliding contact.     

Frictional resistance of new and explanted artificial hip joints

The frictional resistance of 54 explanted Charnley joints and 32 new joints (various types) has been measured in a hip function simulator in dry and lubricated environments.

The friction factors (torque/(normal load × radius) ) for new prostheses were remarkably similar no matter what material or head size was used provided the acetabular component was made of ultra high molecular weight polyethylene (UHMWPE).

Charnley joints, implanted for up to 17 years, were removed from the patients at revision operations and showed that most had a friction factor similar to that of new joints. However, 30% had a friction factor greater than 0.16 when dry and 39% showed friction factors in excess of 0.07 when lubricated (cf 0.1 and 0.04 respectively when new).

All the joints operated under a mixed lubrication regimen.

When the acetabular component was made from UHMWPE, the friction factors were hardly affected by the material of the femoral component. 30% of explanted joints had friction almost twice as great as new joints, but loosening of the prostheses also occurred in some joints whose friction remained low.     

Film‐forming additives ‐ direct and indirect ways to reduce friction

This paper reviews the current understanding of lubricated contacts and the origins of friction in terms of the Stribeck curve. It discusses the various ways that lubricant additives can modify friction in thin‐film lubricated contacts, examining both the nature and properties of the films formed by these additives, as revealed by film thickness measurements, and their consequent effect on the Stribeck friction curve.     

An exploratory investigation of the wear of ski soles on artificial ski slopes

Using a simple service simulation test an exploratory investigation of the wear of ski soles on an artificial ski slope is reported. From the results of dry running tests, lubricated tests, wear measurements and friction and temperature measurements it appears that frictional heating and its control is the dominant factor in ski sole wear.     

Influence of testing method on the contact pressure distribution and its effect on coefficient of friction in polymeric bearings

Influence of contact pressure distribution on the coefficient of friction was investigated for some polymeric bearings in dry and lubricated conditions. Reciprocal pin on plate sliding test and Soda pendulum type sliding tests were carried out. It was found that the contact pressure distribution had a significant effect on the coefficient of friction in lubricated condition. The coefficient of friction became smaller when the pin was sliding with the lower contact pressure side ahead. The coefficient of friction in dry condition does not depend on sliding direction regardless of contact pressure distribution. Furthermore a parametric equation was derived to calculate contact pressure in polymeric journal bearings. The accuracy of the equation was confirmed by Finite Element Method (FEM).     

[成形过程仿真优化与集成计算材料工程]塑性加工摩擦定律的研究进展

塑性加工一般采用润滑油或固体润滑膜对工件进行润滑处理,干摩擦定律作为理解润滑条件下的摩擦行为的基础,可通过类金刚石镀膜镀层模具与板材进行侧拉摩擦试验和高面压摩擦试验来确定。对固体润滑膜下的摩擦定律进行了研究,最后基于干摩擦定律与侧拉摩擦试验,提出了油润滑条件下的摩擦定律。     

Analytical model of sliding friction in an overrunning clutch

The overrunning clutch for pulse-continuously variable speed transmissions (Pulse-CVT) is a roller type of mechanism whose working condition is different from the conventional overrunning clutch. This paper studies the sliding friction of this clutch with the consideration of the dynamic effect of its operation. Both try and lubricated frictions are numerically analyzed. Distributions of the friction among the clutch components are numerically investigated and power loss is estimated.     

Lubrication performance of multialkylatedcyclopentane oils for sliding friction of steel under vacuum condition

Sliding friction experiments under vacuum lubricated with additive-free multialkylatedcyclopentane (MAC) were carried out using a ball-on-disc tribometer with 440C stainless steel as the material of the specimen. Antiwear characteristics of additive-free MAC during the steady friction region under vacuum were shown to be better than those of perfluoropolyether (PFPE). However, it was found that the friction coefficient lubricated with the additive-free MAC under vacuum showed an initial seizure-like high friction of approximately 0.2 at the beginning of the test, followed by a steady low friction of approximately 0.1. It was also found in contrast that PFPE did not show the initial seizure-like high friction but maintained a lower friction coefficient than 0.1 throughout the experiment. The initial high wear volume lubricated with the additive-free MAC was found to be related to the initial seizure-like high friction. The tricresylphosphate formulation prevented the initial seizure-like high friction. Copyright © 2007 John Wiley & Sons, Ltd.     

A new theory of hysteretic sliding friction

This paper supports the concept that the damping properties of rubber contribute the greater proportion of frictional resistance when rubber slides on an irregular lubricated surface. The author presents and largely validates his rigorous mathematical mechano-lattice analogy analysis for calculating the hysteretic sliding friction of, and stresses in rubber sliding on, variously shaped asperities. The analysis allows large deformations and any Poisson's ratio, rigidity or damping factor of the rubber. A method of applying the results of this analysis to the problem of predicting the coefficient of lubricated friction of rubber sliding on roadstones is shown to be reasonably accurate.     

水润滑引起摩擦噪声的机制及实验研究

水润滑摩擦噪声是一种较为常见的现象,会影响产品性能和环境舒适性.分析水润滑引起的摩擦因数一速度特性与摩擦振动系统稳定性的关系,对橡胶块与玻璃片的水润滑摩擦噪声进行实验研究.结果表明:水润滑引起的摩擦特性对系统具有负阻尼作用,当系统等效阻尼为负时,系统失稳,形成摩擦自激振动,是产生水润滑摩擦噪声的根源;摩擦元件的固有频率决定摩擦噪声频率,不同的支撑方式会改变系统模态频率,从而影响摩擦噪声频率.