共查询到19条相似文献,搜索用时 156 毫秒
1.
航空发动机主轴轴承失效模式分析 总被引:2,自引:0,他引:2
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。 相似文献
2.
基于高速滚动轴承试验机对滚动轴承打滑蹭伤展开试验研究,获得不同工况参数下滚动轴承打滑蹭伤的临界转速;研究滚动轴承在打滑蹭伤临界转速下不同运行时间对滚动轴承磨损程度的影响,以及滚动轴承打滑蹭伤后,继续以更高转速运行对滚动轴承磨损程度的影响。结果表明:滚动轴承发生打滑蹭伤瞬间伴随着摩擦扭矩、温度及振动加速度的同步突增,且其在润滑不充分及轻载工况下出现打滑蹭伤时的临界转速更低;滚动轴承在打滑蹭伤临界转速下运转时间越长,磨损越严重,这可能是由于打滑蹭伤破坏滚动轴承表面光洁度,使摩擦因数增大从而导致磨损速度加快;滚动轴承打滑蹭伤后,继续以更高转速运转时易出现二次淬火烧伤,大大降低轴承使用寿命。 相似文献
3.
4.
5.
6.
7.
三点接触球轴承是航空发动机中的关键基础件。目前对三点接触球轴承的仿真分析多基于拟静力学模型,对于打滑、擦伤等特殊行为缺乏解释,而滚球打滑易引起滚道磨损、蹭伤等故障。在对轴承元件进行受力分析的基础上,引入滚球与左右半内圈的接触状态判断条件,采用动力学方法对三点接触球轴承进行了打滑分析。然后,分析了设计接触角及运行参数对轴承打滑率的影响。最后,通过实验研究了滚球通过内圈频率及滚球公转转速随轴向载荷及内圈转速的变化规律,并与动力学模型仿真值进行对比验证了方法的有效性。研究结果表明:轴向载荷越小或转速越高,打滑率越大;在转速和载荷工况条件相同的情况下,轴承打滑率随着设计接触角的增加而增加;而在不同转速工况下,轴承发生打滑的轴向载荷临界值不同,其数值随转速的升高而增加。 相似文献
8.
本文建立了考虑轴承游隙、摩擦力和打滑的非线性滚动轴承动力学模型,并将动力学模型与Archard磨损理论结合,对轴承滚道磨损特性进行研究。首先通过动力学方程,计算出滚动轴承运行过程中的非线性接触力与接触表面滑移速度;然后将计算结果带入磨损模型中,获得滚动轴承外滚道磨损分布;根据磨损后的滚动轴承径向游隙,更新动力学模型,研究轴承磨损特性以及轴承振动响应,并研究不同表面粗糙度下轴承磨损分布的变化趋势,结果表明:表面粗糙度对轴承磨损性能有较大影响,轴承表面粗糙度σ=0.42μm时外圈磨损速度是σ=0.2μm的6.9倍。本文研究成果为滚动轴承系统运行状态评估与寿命预测提供了理论基础。 相似文献
9.
10.
考虑涡动工况的高速滚动轴承打滑失效分析 总被引:7,自引:0,他引:7
打滑蹭伤是高速轻载滚动轴承经常发生的故障。在滚动轴承支承的高速转子系统中,常采用挤压油膜阻尼器(Squeeze film damper,SFD)来降低转子在超过临界转速时所产生的振动和噪声。挤压油膜阻尼器的存在对滚动轴承的打滑蹭伤必会产生影响,需要深入分析其影响机理以保障系统工作的可靠性。SFD通常是利用轴承在SFD结构中涡动来衰减振动。在基于轴承涡动轨迹假设基础上,建立涡动工况下的轴承滚动体运动学及动力学模型,分析不同外载荷、涡动半径、涡动频率等因素对轴承打滑的影响机理,完成挤压油膜阻尼器轴承的打滑失效分析。结果表明,在挤压油膜阻尼器轴承中,涡动的存在会对轴承的打滑产生不利影响;涡动的存在使得轴承的最小膜厚随时间振荡;增大外载荷、减小涡动频率和涡动半径都能改善轴承的运行工况。 相似文献
11.
12.
13.
The effects of steel and ceramic rolling elements on protrusions from the raceway of a bearing were experimentally investigated.
Such protrusions, which are normally caused by solid contaminants in the lubricating oil, create stress concentrations and
lead to a reduction in the rolling contact fatigue life of the bearing. To compare the over-rolling effects of steel and ceramic
rollers, experiments with steel discs with artificial dents on the surfaces were performed using a modified twin-disc machine.
The results show that ceramic rollers can reduce the height of the protruded edge of an artificial dent more than steel rollers,
which means that they are more effective in smoothing a damaged surface. The stresses at the contact were calculated by finite
element analysis based on the deformed profile of the dented surface. The reduction in the stress level due to the smoothing
effect of ceramic rollers is greater than that of steel rollers. According to the Lundberg–Palmgren bearing fatigue model,
that smoothing ensures a significantly longer rolling contact fatigue life for a bearing. To put the idea into practice, a
rolling ball bearing with two of its nine steel balls replaced with silicon nitride balls (referred to as a “partial hybrid
bearing”) was run, together with a full steel bearing of the same model, on a bearing tester in a highly contaminated lubrication
condition. The results show that the partial hybrid bearing suffers from less damage in terms of wear. The post-experiment
examination of the damaged surface of the bearing raceway found that the surface of the partial hybrid bearing was smoother
than that of the full steel bearing. This reveals the smoothing effect of the rolling ceramic element on the contaminant-damaged
bearing surface. 相似文献
14.
高速角接触球轴承中,球与保持架的碰撞会导致球与滚道的冲击滑动,从而引起滚道划伤和轴承早期失效。为探究球与保持架的冲击碰撞导致的瞬时滑动,以某高速角接触球轴承为研究对象,通过对联合载荷下角接触球轴承的动力学仿真,分析了变速工况及保持架结构参数对球与保持架的冲击碰撞、球与滚道的冲击滑动以及零件磨损率的影响。结果发现,加减速及恒定转速下,球与保持架的运动呈现周期性变化;由于球进入和离开径向载荷区域时公转角速度的变化,球与保持架碰撞并导致球相对内、外圈滚道发生冲击滑动;为适应球公转角速度的变化,适当增大兜孔间隙,可以减小球与保持架兜孔碰撞力的大小和频率,从而减小球与滚道的冲击滑动以及保持架的磨损率。 相似文献
15.
角接触球轴承在运行过程中的润滑状况至关重要,润滑油直接影响滚动轴承的接触状态。为分析角接触球轴承的润滑状况以及考虑润滑时轴承的机械特性,基于有限元和晶格玻尔兹曼方法,建立了双向流固耦合轴承仿真模型,对角接触球轴承进行动力学有限元仿真和润滑流体仿真,并与轴承拟静力学理论计算结果进行对比,验证模型的准确性。分析结果表明,保持架与滚珠接触并撞击,在轴承腔内油膜压力最大,滚珠与内圈、外圈滚道接触区分别为第二、第三大油膜压力区。润滑油受滚珠公转影响,沿着滚珠转动方向流动,实现对滚珠与内圈、外圈和保持架之间的润滑。滚珠运动和最大接触应力仿真结果与轴承拟静力学理论求解结果一致,即流固耦合仿真模型计算轴承机械特性具有较高的准确性。 相似文献
16.
A new form of rolling contact damage was discovered in the fatigue tests of series 6206 deep groove ball bearings under pure radial load with grease lubrication. The appearance of the damage reveals a few cracks at right angles to the rolling direction of the ball, along with the formation of a dent about 20 μ m deep in the raceway surface. This is found to occur only on the stationary outer ring raceway and the ball surface and is distributed widely within the load zone. Furthermore, under the raceway surface several cracks propagating into the substrate at an angle of about 60-80 degrees relative to the raceway surface are observed not only under the damage site but also in other nearby locations. Only the cracks at the damage position open up to the surface. The grease used for the test contained a lithium complex thickener with mineral oil as the base oil with a kinematic viscosity of 141 mm2/s at 40°C. On the test bearings two pure radial load levels of 9.14 and 12.13 kN were applied. In order to prevent the occurrence of seizure at each load, the speed of the inner ring of the test bearing was maintained at 1800-2500 min? 1 and 600-800 min? 1, respectively, to keep the outer ring circumference temperature below 65°C. It is suggested that the damage is caused by metal-to-metal contacts due to lubricant starvation under grease lubrication and to a decrease in oil film thickness due to local increases in temperature. 相似文献
17.
采用内滚道、外滚道和弹性环组成滚动载流摩擦副,通过载流摩擦试验研究了其在不同转速下的载流摩擦学性能和材料损伤。结果表明:随着转速从240 r/min增加到600 r/min,摩擦副稳态运行期间的摩擦力升高,接触电阻下降;摩擦前期材料损伤形式主要以接触表面金属塑性变形为主,摩擦平稳期以材料剥落为主;在相同的初始接触条件下,高转速促进表面疲劳和材料磨损,试验后弹性环磨痕宽度明显变宽,磨损量逐渐增大,表面氧化程度下降,O和Cu原子个数比降低;磨痕宽度增幅相近的条件下,同等转速下的摩擦力增幅小于变速条件下的摩擦力增幅;转速增加引起的摩擦力增大与高转速下弹性环滑滚增加也有关系。 相似文献
18.
An analytical model to investigate skidding in rolling element bearings during acceleration 总被引:1,自引:0,他引:1
Wenbing Tu Yimin Shao Chris K. Mechefske 《Journal of Mechanical Science and Technology》2012,26(8):2451-2458
Skidding, which occurs in rolling element bearings during shaft rotational acceleration, causes wear and incipient failure. This paper presents an analytical model to investigate skidding during rolling element bearing acceleration, taking account of the contact force and friction force between the rolling elements and the races and the cage, gravity, and the centrifugal force of the rolling elements. The Hertzian contact theory is applied to calculate the non-linear contact force. The Coulomb friction law is used to calculate the friction force. All forces above are included in force equilibrium equations to derive the non-linear governing equations of the bearing during acceleration, and are solved using a fourth-order Runge-Kutta algorithm with fixed time step. The proposed model is verified by comparison to other published results and with experimental results. The proposed model can be used to investigate skidding in rolling element bearings during acceleration and the transient motion behavior of rolling elements, and it will lay the theoretical foundations for eliminating skidding in rolling element bearings. 相似文献
19.
转速波动工况滚动轴承打滑动力学特性分析 总被引:1,自引:0,他引:1
滚动轴承实际运转过程中经常存在的转速波动现象,对滚动轴承的运行状态产生重要影响。基于Hertz接触理论和变形-位移相容条件建立滚动体与套圈的相互作用模型,采用非线性弹簧模拟滚动体与保持架间的相互作用,建立了转速波动工况下滚动轴承打滑动力学模型。通过与实验测试结果的对比,验证了所提出的动力学模型的正确性,并在此基础上分析了转速波动对滚动轴承打滑的影响及不同转速波动幅值、频率下滚动轴承的打滑特性。结果表明:轴承转速波动会造成保持架转速出现波动,导致轴承出现打滑,且滑动主要出现在滚动体与内圈之间;转速波动幅值对轴承打滑影响较大而频率影响较小。 相似文献