计入表面吸附膜的热弹流润滑体系建模及分析

目的 研究表面吸附膜在热弹流润滑中的作用机理.方法 构建考虑表面吸附膜的非牛顿流体点接触热弹流润滑模型,分析润滑剂的非牛顿性、吸附膜及钢的热传导系数对热弹流润滑性能的影响.结果 润滑剂的非牛顿性及吸附膜的计入对油膜压力和厚度的影响很小.与牛顿流体相比,非牛顿流体可以得到较低的温升和摩擦系数.同时,随着非牛顿流体特征剪应...     

线接触热弹流润滑的数值分析

基于Ree-Eyring流变模型,建立线接触热弹流润滑方程,通过数值计算得出了载荷参数、速度参数、材料参数和滑滚比对于二次压力峰、最小油膜厚度和最大油膜温度的重要影响.     

冲击载荷下不同载液磁流体直齿圆柱齿轮的弹流润滑数值分析

建立磁流体润滑渐开线直齿轮的弹流润滑模型,应用多重网格法和多重网格积分法,求得直齿轮非稳态弹流润滑问题的完全数值解,分析冲击载荷对不同载液磁流体弹流润滑的影响。冲击载荷作用下,探究两直齿轮接触点压力和膜厚的变化规律。结果表明:二酯基D01磁流体的膜厚最大,压力最小;酯基H02磁流体的膜厚最小,压力最大;二酯基D01磁流体润滑膜在冲击载荷作用下,传动比越大,压力越小,膜厚越大;二酯基D01磁流体润滑膜在冲击载荷作用下,传递功率越大则轮齿上的载荷越大,压力越大,膜厚越小。     

低流量脉动润滑脂泵在流变实验中的应用

简单介绍了低流量脉动泵的结构特点。在高精度输送实验台上，选择多种直径的管路进行了润滑脂流变实验，测得在不同管壁和管径中流动曲线不重合。分析其主要影响因素是壁滑移；本文建立了扣除壁滑移的真实流变模型和流动方程，得出了不同管径和管壁中的真实流动曲线基本重合的结论。为研究润滑脂集中润滑管道输送系统的流动阻力特性和壁滑移对润滑脂弹流润滑的影响打下了基础。     

新型金属热模锻用非石墨型润滑剂的研究

针对目前广泛用在金属热模锻中的石墨型润滑剂存在的污染环境和难以清理等问题,以无机层状氮化物和硬脂酸盐为主要固体润滑材料,得到系列非石墨型润滑剂,并对其润滑性能和润滑机理进行了研究。结果表明,4种系列润滑剂中,以无机层状氮化物配以复合硬脂酸盐类为主要成分的热模锻润滑剂具备最优良的悬浮性、成膜性,并且润滑性能与石墨型润滑剂相当,清理容易。目前,该新型非石墨型润滑剂可以在一定范围内替代石墨型润滑剂,是一种环保型润滑剂。     

接触表面性质对圆柱滚子轴承混合润滑的影响

目的为了提高圆柱滚子轴承的润滑性能,研究滚子与外圈表面纹理及硬弹比对圆柱滚子轴承混合润滑的影响。方法基于平均流量模型、非牛顿效应、热效应和粗糙峰的弹塑性变形,建立了圆柱滚子轴承有限长线接触热混合润滑模型。研究了表面纹理及硬弹比对膜厚、膜厚比、载荷比、平均摩擦系数及最高温度的影响。结果随着表面纹理参数的增大,油膜厚度逐渐减小,粗糙峰接触压力、平均摩擦系数和载荷比逐渐增,最高温度先减小后增大,最小膜厚先增大后减小。但表面纹理参数小于1/3时,对最小膜厚的影响非常小。表面硬度引起的完全塑性变形、弹塑性和塑性变形、完全弹塑性变形对润滑状态的影响不同。在硬弹比处于0.01～0.03时,粗糙峰同时发生弹塑性和塑性变形,油膜厚度、最小膜厚、载荷比、平均摩擦系数、粗糙峰接触压力及最高温度不随表面硬度而变化。当硬弹比小于0.01时,粗糙峰产生完全塑性变形;当硬弹比大于0.03时,粗糙峰发生完全弹塑性变形。这两种情况的载荷比、平均摩擦系数、粗糙峰接触压力及最高温度均随着表面硬弹比的增大而增大。在不同工况下,表面硬度与表面纹理参数对圆柱滚子轴承润滑状态的影响存在差异。在表面纹理参数小于1/3时,表面硬度的影响占主导地位;在表面纹理参数大于1.0时,表面纹理参数的影响占据主导地位。结论表面纹理参数等于1.0时,润滑状态最好;硬弹比处于0.01～0.03时,综合润滑性能最好。在不同条件下,表面纹理参数与表面硬度对润滑影响的程度不同。因此,圆柱滚子轴承混合润滑中,存在最佳的表面纹理参数和表面硬弹比。     

环境温度变化对水润滑动静压轴承的热弹流影响

目的研究不同季节或地域以及外部降温对水润滑动静压轴承热弹流的影响。方法选取小孔式水润滑动静压滑动轴承为研究对象,采用考虑了热效应的Reynolds方程对水润滑动静压滑动轴承进行热弹流润滑分析,研究了不同温度边界条件下三种轴瓦材料的水润滑动静压滑动轴承润滑膜的温度变化及其压力膜厚的变化。结果当轴瓦、轴颈的温度相同且异于润滑剂初始温度(313 K)时,轴瓦、轴颈温度越低,润滑膜的温度越低,在入口区和出口区出现明显的温度变化,轴瓦、轴颈温度越低,润滑膜的膜厚越大,第二压力峰越明显。轴承外部降温,使轴瓦温度(297.35、281.7 K)保持低于润滑膜以及轴颈的初始温度(313K),轴瓦温度越低,润滑膜的温度越低,入口区以及出口区的温度也发生变化,润滑膜的膜厚增大,第二压力峰增大。对比轴瓦、轴颈温度同时降低和轴瓦温度降低这两种工况,润滑剂温度的变化趋势与压力膜厚的变化趋势相同,但变化幅度不同。结论由于轴承所处季节或地域不同,轴瓦、轴颈的温度异于润滑剂初始温度,外部环境温度越低,润滑膜的膜厚越大,有利于润滑。通过外部降温的形式使轴瓦保持低温状态,同样可以使润滑膜的膜厚增大,有利于润滑。     

铜套的液氮冷装工艺

在机床的制造与维修中，经常会遇到滑动轴承铜套过盈装配的问题。铜套的过盈装配要依据轴承的润滑、载荷、转速等条件来确定过盈量的大小，对于机械压力机，很多滑动轴承均工作在低速、重载的条件下，尤其是一些老式压力机，润滑一般为间歇式油脂润滑，工作中，润滑很不充...     

结构参数对转盘轴承承载与润滑性能的影响

转盘轴承的承载和润滑性能是判断其能否满足主机需求的关键指标。以低速重载交叉滚柱式转盘轴承为研究对象,综合ADAMS动力学仿真与弹流润滑理论研究了接触角、滚动体直径和数量等结构参数对转盘轴承承载和润滑性能的影响。结果表明:随着接触角的增大,最大接触载荷和膜压逐渐减小,而膜厚逐渐增大,因此适当增大接触角可以提高转盘轴承的承载和润滑性能。随着滚动体直径的增大与数量的减少,最大接触载荷逐渐增大而最大接触应力逐渐减小,膜厚逐渐增大,膜压逐渐减小,因此在转盘轴承设计中,应综合考虑承载和润滑性能两方面的因素确定合适滚动体直径和数量。     

基于热混合润滑的钢/橡胶接触表面水润滑增强调控

目的 增强钢/橡胶摩擦副的润滑性能,为提高混合润滑状态下水润滑轴承的性能提供参考。方法 建立水润滑条件下钢/橡胶摩擦副的热混合润滑模型,讨论热效应对润滑性能的影响,并在此基础上进一步研究表面粗糙度、水基润滑剂黏度和供水压力对水润滑增强调控的作用。结果 与等温解相比,热效应使Stribeck曲线发生了右移,摩擦因数和载荷比增大,膜厚比降低。最高水膜温度随着转速的增加而升高,热效应对混合润滑性能的影响显著。减小摩擦副表面粗糙度,Stribeck曲线向左移动。在相同转速下,载荷比随着表面粗糙度的减小而降低,膜厚比反之。表面粗糙度越大,水膜温度越高,最高温度位于出口区,且钢的表面温度低于水膜和橡胶的表面温度。当水基润滑剂的黏度增大时,膜厚比增大,载荷比和最高水膜温度降低,Stribeck曲线发生左移。增加供水压力可以改善水膜压力分布,使水膜承载区增大、压力减小,粗糙峰接触压力和承载区减小,导致载荷比减小、膜厚比增加,Stribeck曲线向左偏移,水膜最高温度降低。当接触区由边界润滑向混合润滑过渡时,水膜最高温度出现拐点,且水膜最高温度拐点随着供水压力的增加而左移。结论 热效应会降低摩擦副的混合润滑性能,因此在混合润滑中不能忽略。考虑热效应时,通过减小表面粗糙度,或增加水基润滑剂黏度和供水压力,均有利于增强钢/橡胶接触表面水润滑的混合润滑性能。     

DEVELOPMENT AND APPLICATION OF WATER-IN-OIL EMULSIONS FOR ZINC HOT ROLLING

ＤＥＶＥＬＯＰＭＥＮＴＡＮＤＡＰＰＬＩＣＡＴＩＯＮＯＦＷＡＴＥＲ－ＩＮ－ＯＩＬ　ＥＭＵＬＳＩＯＮＳＦＯＲＺＩＮＣＨＯＴＲＯＬＬＩＮＧＪｉａｎｇ；ＪｉａｎｃｈｕｎＭａｏ；Ｄａｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｃｈｉｎｅＥｎｇｉｎｅｅｒｉｎｇ，Ｃｅｎ...     

重载变速冲击工况下MoDDP/CaB复合润滑油添加剂的润滑性能

为解决机械设备在恶劣工况下由润滑失效而导致的设备故障甚至安全生产事故问题,进一步提升机械设备的运行稳定性和安全性,研究纳米硼酸钙（CaB）和二烷基二硫代磷酸钼（MoDDP）单一润滑油添加剂和复合润滑油添加剂的减摩抗磨效果,并探究其润滑作用机制。研究结果表明,重载、变速、冲击工况条件下 1.5 wt.% MoDDP / 3.0 wt.% CaB 复合润滑油添加剂具有良好的减摩抗磨效果,与基础油相比,在不同转速下可最大降低 65.1%的摩擦因数和 80%的磨痕深度,施加 50 N 冲击载荷时,可分别降低66.7%的摩擦因数和76.5%的磨痕深度。MoDDP / CaB复合润滑油添加剂在润滑过程中能生成包含C-C、 Fe₂O₃、FeB 和 MoS₂的金属化合物层,添加剂中的 CaB 和 MoDDP 能够相互促进彼此反应,增加 FeB / MoS₂润滑膜的生成量, 对比单一的添加剂和基础油,复合添加剂具有更好的自修复性能和协同功效,形成具有高承载力的润滑油膜,提高了复合润滑油的抗磨减摩性能。MoDDP / CaB 复合润滑油添加剂的制备可以充分综合利用抗氧化剂与极压耐磨剂的稳定、优异润滑特性,研究结果可为复合添加剂的广泛应用提供数据支持和理论支撑。     

高线轧机辊箱油膜轴承润滑特性分析

高线轧机油膜轴承工况条件极为恶劣,为了保证轧机油膜轴承在多种工况下的安全性,采用有限元方法耦合求解润滑方程和温黏方程,分析了不同工况下轧机油膜轴承的关键静动特性润滑性能参数,并对多种工况条件下轴承的润滑特性进行了校核。在高速重载工况下,轴承的温升偏高,可以通过增加冷却润滑油的流量或采用具有高热导率的轴承材料来加强散热;在低速重载工况下,轴承的比压较高,油膜厚度较小,可以通过增大轴承宽度来提高轴承的安全性。同时,应当减小轧机在恶劣工况条件下的连续运行时间,降低对轴承的损伤,延长其使用寿命。     

Orthogonal experiment investigation on wear resistance of MoSi2

The influence of lubricant conditions, wear loads, and counterparts on the friction and wear characteristics of an MoSi2 material was investigated by means of orthogonal analysis. Orthogonal experiment results show that the order of influencing degree of the factors is lubricant condition > load > counterpart. MoSi2 has excellent friction-wear comprehensive properties against higher-hardness counterparts on the higher load and 20 oil lubricant conditions.     

Sliding Wear Response of a Bronze Bushing: Influence of Applied Load and Test Environment

This investigation pertains to the examination of the sliding wear behavior of a leaded-tin bronze bushing under the conditions of varying applied loads and test environments against a steel shaft. The test environment was changed by adding 5% of solid lubricants like talc and lead to an oil lubricant separately as well as in combination; the fraction of the two (solid) lubricants within the solid lubricant mixture was varied in the range of 25-75% in the latter case. The wear performance of the bushing was characterized in terms of the wear rate, frictional heating, and friction coefficient. The increasing load led to deterioration in the wear response, while the addition of the solid lubricant particles produced a reverse effect. Further, an appreciable difference in the wear behavior was not observed when the tests were conducted in the oil plus talc and oil plus lead lubricant mixtures. However, the oil containing lead and talc together brought about a significant improvement in the wear response; best results were obtained in the case of the lubricant mixture consisting of lead and talc together in the ratio of 3:1 in the oil. The observed wear behavior of the samples has been discussed in terms of specific characteristics of various microconstituents. The features of the wear surfaces and subsurface regions further substantiated the wear response and enabled us to understand the operating material removal mechanisms.     

铝板带冷轧水基乳化液润滑膜形成特点研究

探讨了不同浓度的水基乳化液形成润滑膜的特点。低速轧制时,随着轧制速度的提高,润滑膜厚度增大。当轧制速度超过临界值时,随着轧制速度的提高,润滑膜厚度降低。考虑速度对乳化液黏度的影响,用4阶多项解函数拟合乳化液黏度随轧制速度变化曲线,对Reynold方程进行修正,使非牛顿流体水基乳化液润滑膜厚度的计算更准确。     

ANALYSIS OF DRAWING UNDER LUBRICATION OF NON-NEWTONIAN LUBRICATING MATERIALS

ＡＮＡＬＹＳＩＳＯＦＤＲＡＷＩＮＧＵＮＤＥＲＬＵＢＲＩＣＡＴＩＯＮＯＦＮＯＮ－ＮＥＷＴＯＮＩＡＮＬＵＢＲＩＣＡＴＩＮＧＭＡＴＥＲＩＡＬＳＬｅｉＺｈａｎｂｏ；ＷａｎｇＺｈａｎｘｕｅ；ＧａｏＹｏｕｚｈｉ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇ...     

Sliding Wear Behavior of Cast Iron: Influence of MoS<Subscript>2</Subscript> and Graphite Addition to the Oil Lubricant

The present study discusses sliding wear characteristics of a gray cast iron over a range of applied loads in oil lubricated condition. Effects of MoS₂ and graphite addition to the oil lubricant in governing the wear behavior have also been studied. The wear rate increased with load in general with a few exceptions in the case of oil plus 5% MoS₂ wherein it had a tendency to show a reverse trend in the intermediate load range. Addition of 5% graphite to the oil brought about a decrease in the wear rate without affecting seizure resistance. Increasing quantity of graphite in the oil from 5 to 10% practically did not affect the wear rate at lower loads. However, it led to significantly lower wear rates at higher loads and also offered higher seizure resistance. In the case of oil plus 5% MoS₂ lubricant mixture, the wear rate of the samples was higher than that of the lubricant with 5% graphite when tests were conducted at lower loads while identical response was observed at higher loads in both cases. Seizure resistance of the samples was not affected by the addition of 5% graphite and MoS₂ to the oil. The frictional heating also increased with load in general, except in the case of oil containing 5% MoS₂ and 10% graphite wherein it remained practically unaffected in the intermediate load range. The presence of 5% graphite and MoS₂ in the oil lubricant brought about reduced frictional heating, except in the case of oil plus 5% graphite mixture wherein the trend reversed, and oil plus 5% MoS₂ leading to comparable frictional heating during specimen seizure. Increasing test duration caused higher frictional heating. Adhesion was observed to be the principal wear mechanism while microcracking assisted delamination and abrasion also contributed to material loss.     

Research on experiments and action mechanism with water vapor as coolant and lubricant in Green cutting

Green cutting has become focus of attention in ecological and environmental protection. Water vapor is cheap, pollution-free and eco-friendly. Therefore water vapor is a good and economical coolant and lubricant. Water vapor generator and vapor feeding system were developed to generate and feed water vapor. Comparative experiments were carried out in witch YT15 (P type in ISO) tool was used in cutting C45 steel under the conditions of compress air, oil water emulsion, water vapor as coolant and lubricant and dry cutting, respectively. The experimental results showed that with water vapor as coolant and lubricant the cutting force is further reduced, the friction coefficient, the chip deformation coefficient and the surface roughness value decreased and the cutting temperature lowered. Kinetic model of penetration capillary in tool–chip interface of cutting fluid revealed that the lubricity effect is much better with water vapor as coolant and lubricant because of its excellent penetration performance and forming of low shearing strength lubrication layer. Therefore, the use of water steam as coolant and lubricant proves to be a green cutting technique.