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假设在一个表面上存在单个粗糙峰或粗糙谷,采用数值分析方法研究大滑滚比下粗糙表面对线接触热弹流润滑接触的影响。研究发现:粗糙峰和粗糙谷造成油膜压力、膜厚和温升曲线的局部波动,其中压力的波动最为明显;在滑滚比较小时,粗糙峰和粗糙谷对压力、膜厚和温升曲线的影响较大, 随着滑滚比的增加,影响逐渐降低; 随着滑滚比的增加,粗糙峰幅值增加对压力、膜厚和温升曲线造成的波动也逐渐减弱。研究结果对于揭示滚珠丝杠或无保持架轴承等的润滑油膜形成和失效有重要意义。 相似文献
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表面粗糙纹理对非牛顿热弹流润滑性能的影响 总被引:1,自引:0,他引:1
建立了考虑表面粗糙度的点接触热弹流润滑模型,假设滚滑工况下慢速运动的固体表面是粗糙的,而快速运动的固体表面绝对光滑.卷吸速度沿接触区短半轴方向,表面粗糙纹理以正弦函数来表征,润滑剂符合Ree-Eyring非牛顿流体粘性定律.通过完全数值求解,讨论了3种不同构成的粗糙纹理对弹流润滑性能的影响.其中2种是周期性时变问题,求解是从一个准稳态解开始逐个瞬时迭代来实现的.结果表明,粗糙纹理会使得接触区里对应处产生明显的局部高压,局部温升,油膜厚度也相应减小.而纵向粗糙度时润滑效果最差,因为具有更危险的最小膜厚值. 相似文献
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单粗糙峰通过接触区全过程的时变热弹流数值仿真 总被引:1,自引:0,他引:1
建立了带单粗糙峰的表面滚滑工况的点接触时变热弹流模型,数值模拟了钢与钢接触、快速表面带单粗糙峰通过接触区的全过程。结果表明,接触区内的粗糙峰会引起局部高压,当粗糙峰较高时,润滑膜会变得极薄,这对润滑的可靠性是不利的,而局部压力高峰也会严重降低材料的表面疲劳寿命。 相似文献
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为了提高巴氏合金在油润滑条件下的摩擦学性能,在巴氏合金表面加工凹坑微织构并利用光固化填充方法填充六方氮化硼(h-BN)固体润滑剂,制备出h-BN与表面微织构相结合的复合润滑结构。研究复合润滑结构在油润滑条件下的摩擦学性能及其减摩润滑机制。结果表明:复合润滑结构的摩擦学性能远高于未织构面和纯织构面;当凹坑微织构直径较小时,织构密度为10%~20%时,复合润滑结构摩擦因数较小,而凹坑直径较大时,随着织构密度的增加,复合润滑结构摩擦因数逐渐减小;当织构密度小于20%时,凹坑直径较小的复合润滑结构摩擦因数小,当织构密度达到30%时,随着凹坑直径的增加,复合润滑结构摩擦因数减小。复合润滑结构能够改善巴氏合金表面摩擦学性能,是因为h-BN固体润滑剂的释放在巴氏合金表面形成了固体润滑薄膜,避免了润滑油膜较薄处的巴氏合金表面直接与45钢表面接触,且释放h-BN固体润滑剂后的微织构凹坑可以起到收集磨粒,储存润滑油的作用。 相似文献
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为提高核主泵屏蔽电机用水润滑石墨轴承的摩擦润滑性能,采用高速雕铣机在石墨试样表面加工不同形状、深度和面积占有率的凹坑织构,通过水润滑条件下的销盘摩擦试验,测试分析凹坑织构结构参数对石墨材料水润滑性能的影响。结果表明:在水润滑条件下凹坑织构具有一定的减摩效果,随着转速的增加,凹坑织构的动压效应增强,石墨试样摩擦因数减小;随着载荷的增加,石墨试样摩擦因数减小;随着凹坑深径比、面积占有率的增加,石墨试样摩擦因数均呈现先减小后增大的变化趋势,当凹坑深径比为0.5、凹坑面积占有率为3%左右时,石墨试样摩擦因数最小;相较三角形凹坑织构,正方形凹坑和圆形凹坑织构的减摩效果更好。 相似文献
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M. Debicki 《Wear》1979,52(1):13-26
Lubricating phenomena are described thermodynamically. Tribological parameters, in particular pressure and relative sliding speed, are related to thermodynamic properties of the tribological system such as thermodynamic potential, enthalpy and entropy. On this basis tribological thermodynamic models of the viscosity, flow properties and lubricating performance of materials are deduced. Changes of lubricating performance in a tribological system are determined by considering such tribological thermodynamic parameters. A tribological thermodynamic model of lubricating phenomena is therefore obtained which with the use of suitable thermodynamic data for optimum tribological parameters allows the prediction of the lubricating performance of tribological systems. 相似文献
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采用分子动力学模拟方法建立光滑和粗糙2种固体壁面结构,研究季戊四醇四酯润滑剂在不同压力、薄膜厚度下,在恒定剪切速度和温度下的薄膜润滑行为。分析壁面间润滑薄膜的密度分布,以及剪切过程中润滑剂的速度分布。输出固体壁面在x向和z向的力学响应,并计算摩擦因数。结果表明:表面纳米结构降低了润滑薄膜的厚度,减弱了润滑薄膜分层现象;当润滑薄膜厚度较大时,V形纳米沟槽有助于减小薄膜润滑系统的摩擦因数;润滑薄膜厚度较小时,V形纳米沟槽表面润滑状态容易从流体润滑转变到边界润滑状态,摩擦因数增大。 相似文献
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为探究齿面沟槽织构参数对渐开线圆柱直齿轮润滑性能的影响,简化齿轮啮合模型选取并建立单元沟槽CFD仿真模型,通过分别求解未考虑和考虑空化效应的2种仿真模型,获得不同沟槽尺寸参数对模型润滑性能的影响规律。结果表明:沟槽织构的存在改变了流体域油膜压力分布状态,具有更高的油膜承载力和更好的动压性能;不考虑空化效应时,油膜承载力大小与沟槽宽度的变化密切相关,而受沟槽深度变化的影响较小,沟槽织构浅且宽时齿面具有更好的润滑性能;考虑空化效应后,表面润滑性能随沟槽宽度与深度的变化而动态变化,相较于不考虑空化效应,沟槽宽度更窄、深度更深时齿面具有更好的润滑性能;在沟槽深度与宽度均较小时,空化效应对动压性能的影响不是很大,在沟槽深度较小而沟槽宽度较大时,空化效应对动压性能的影响较大;而在沟槽深度较大时,空化效应对动压性能的影响始终较大,且不受沟槽宽度变化的影响。 相似文献
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W. Tuszynski 《Tribology Letters》2006,24(3):207-215
An effect of the type and concentration of lubricating additives (antiwear and extreme-pressure) on the rolling contact fatigue was investigated and discussed in the chemomechanical way. To this end complementary elemental and chemical surface analyses of the worn surface were performed, accompanied by calculation of the EHL film thickness. It is shown that if the lubricating film is thin and the surface of test specimens has numerous defects, fatigue failures are initiated on the surface, which strengthens an impact of surface related tribochemical phenomena on the rolling contact fatigue. 相似文献
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Shigeru Yonemura Susumu Isono Masashi Yamaguchi Yoshiaki Kawagoe Takanori Takeno Hiroyuki Miki Toshiyuki Takagi 《Tribology Letters》2014,55(3):437-454
It has been previously reported that the friction between a partially polished diamond-coated surface and a metal surface was drastically reduced to zero in the atmosphere as relative speed was increased (Nakamori et al. in Diam Relat Mater 14:2122–2126, 2005). On the other hand, it has also been reported that laser-textured surfaces have good tribological performance in the case of gas lubrication (Kligerman and Etsion in Tribol Trans 44:472–478, 2001). The surfaces in the aforementioned two cases have a micro/nanoscale structure. It is expected that both surfaces are levitated by a high-pressure gas film between sliding surfaces by the same mechanism. In the present work, the mechanism of high gas pressure generation is clarified by the performance of numerical simulations and by theoretical analysis. The following two features of pressure distributions on textured surfaces were found to induce high gas pressure. First, gas pressure increases in the direction of the counter surface’s motion over the dimple region. Second, the pressure distribution over the flat region is convex upward, and hence, the high pressure obtained at the outlet of the dimple is maintained for a long distance in the flat region. The causes of such pressure distributions are herein explained analytically. The governing factor of pressure distributions and the optimal dimple location in the period of the repeated surface pattern are also discussed. Furthermore, the knowledge obtained here is utilized to design the surface structure to obtain high gas pressure. 相似文献
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针对VMUC100轴承滚道超精研机振荡头架滑移拖板机构存在的润滑效果差易产生干摩擦的问题,对该机构相对运动表面增加润滑油沟,消除了干摩擦现象,提高了运行精度和稳定性。 相似文献
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In this paper, we discuss the developments of a novel dimples journal bearing and the experimental results on friction performance. Based on the phyllotaxis theory of biology, the lubricating dimples were positioned in the internal circle surface of the journal bearing. The effects of phyllotactic pattern parameters on the distribution of these dimples were discussed in detail and simulated. A series of experimental results was presented to examine the effect of phyllotactic coefficients and dimple diameters on the friction characteristics. It was shown that the friction performance of journal bearings can be evidently improved under the proper tested parameters. Meanwhile, the friction coefficients, which are obtained in the dimples journal bearings with phyllotactic pattern and linear pattern, were presented to reveal their differences, and lower values of friction coefficients were achieved for the proposed dimples journal bearing under the tested radial load and rotational speed. 相似文献