共查询到18条相似文献,搜索用时 454 毫秒
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通过对某车型在起步过程中出现“咔哒”异响现象进行分析,最终确定起步异响是由于变速器输出轴内端面与联轴器接触端面粘滑振动诱发产生。根据接触结构特点理论计算了粘滑发生可能性并建立简化物理模型分析粘滑运动模式。同时也分析了与异响问题相关结构特点对异响的影响因素并提出多种工程化控制因素,最终采用在接触面间添加特制减摩垫圈改变接触结合界面动态摩擦特性的方法有效解决了该车型起步异响问题。目前,国内外对传动系统中的粘滑问题研究较少,本文研究成果对后续车型开发设计中类似问题的规避具有重要指导意义。 相似文献
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通过对某前驱SUV车型起步前进、倒车过程中前底盘的“咔嗒”异响解析,最终锁定异响由轮毂轴承与驱动轴配合端面处产生Stick-slip 效应(粘滑摩擦)导致,通过理论校核配合结构设计参数进一步确认配合端面存在相对粘滑摩擦风险。借助建立端面粘滑摩擦物理模型的方式,分析粘滑摩擦过程中法向载荷、摩擦系数等因素的影响。利用一种双面涂抹减摩剂的圆环垫圈,装配在轮毂轴承与驱动轴配合端面处,用以改变原始状态下的摩擦特性,有效解决了车辆前进、倒车过程中的异响问题。目前,行业内对端面粘滑摩擦异响研究较少,此研究成果在新车型研发初期对预控类似问题具有重要工程指导意义。 相似文献
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针对摆线针轮行星传动啮合过程中啮合齿面摩擦行为影响系统动态特性、传动效率及接触疲劳特性等问题,基于牛顿流体及指数率、Ree-Eyring模型建立摆线针轮线接触时变热弹流润滑数值分析模型,获得理想安装的摆线针轮副完整啮合周期内摩擦力、摩擦系数及摩擦损失功率变动。结果表明,基于牛顿流体及指数率流体模型所得摩擦系数与工程实际不符;基于Ree-Eyring模型纯滚动啮合产生的热效应在重载下对啮合过程中膜厚、摩擦损失功率影响较大,对压力、摩擦系数影响较小。研究非牛顿流体特征参数与摆线针轮传动设计参数对啮合中摩擦系数、摩擦损失功率影响规律表明,流体特征应力增加摩擦系数及损失功率均减小;短幅系数取较大值时大部分啮合区间摩擦系数增加、摩擦损失功率减小。 相似文献
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《振动工程学报》2016,(3)
建立了摩擦离合器接合过程中传动系统动力学特性分析的模型。建模中,考虑到离合器接合过程中存在的粘滑现象,对离合器黏着和滑动状态下的摩擦力矩进行分析,得到了离合器接合过程中的摩擦力矩的计算模型。在进行模型的计算分析时,引入了Karnopp摩擦模型,实现了黏着和滑移状态下,动力学方程的一致性。在已知发动机转速时,计算分析了离合器过程中从动盘的角速度的与摩擦系数随接合面相对滑移变化的关系。研究了离合器从动盘总成的扭转刚度和波形片的轴向刚度对起步抖动的影响。针对两款车存在的起步抖动问题,根据理论计算的结果,对这两款车的离合器从动盘扭转刚度和波形片轴向刚度进行了优化,试验结果表明:利用优化的离合器从动盘的性能参数,两款车的起步抖动问题有了较大的改善。 相似文献
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建立了含齿面摩擦的平行轴斜齿圆柱齿轮传动变速过程动力学模型,在建立模型时,接触线的位置和滑动速度是由主动轮转角确定,使用齿轮线位移和角位移作为广义坐标,因此这样的模型可适用于斜齿轮传动系统的变速过程分析,而且在该模型中,齿面摩擦力是用变摩擦系数获得的。选择一对斜齿轮对其加速过程进行数值计算,并与采用定摩擦系数和不考虑摩擦的计算结果在时域和魏格纳分布上进行对比分析,结果发现:摩擦会降低斜齿轮传动系统出现脱啮现象的临界转速,且具有阻尼和激励的双重作用,能改变斜齿轮传动的动力学响应,而且采用变摩擦系数或定摩擦系数所获得的动力学响应也有所不同。 相似文献
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针对所提出的芯轴式摩擦支撑的构造特点,建立了滑动摩擦动热转换的滞回能量耗散模型,研究了摩擦生热对芯轴式摩擦支撑性能的影响,分析了初始摩擦力、摩擦片厚度、摩擦芯轴比热容和摩擦系数等因素对芯轴式摩擦支撑的力学性能和温度场的影响规律,给出了摩擦支撑在摩擦生热影响下的摩擦力增长值理论计算公式,并通过数值分析结果进行了验证。分析结果表明芯轴式摩擦支撑在摩擦过程中温度不断上升,高温区主要集中在摩擦芯轴和摩擦片的摩擦接触面上,并且随着摩擦片厚度、初始摩擦力和摩擦系数的增加,摩擦热效应越明显,随着材料比热容的增加,摩擦热效应下降。 相似文献
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核岛安全壳-吊车耦合体系在强震下的可维持性是影响核安全的关键因素之一。为揭示粘滑效应对体系抗震性能的影响,采用修正的LuGre模型描述驱动轮与轨道之间stick-slip行为;引入线性互补问题描述各叠放部件的非光滑接触,建立考虑多点摩擦接触的环行起重机刚柔耦合动力学模型;选取代表性的强震记录作为基岩地震动,对多工况下的地震瞬态响应进行分析,揭示耦合体系地震响应机理。研究结果表明:制动轮与轨道之间的摩擦力是将体系维持在既定位置的关键,动力学模型必须考虑粘滑效应;跳轨行为受三向地震共同影响,水平强震和竖向弱震亦可诱发跳轨;瞬时跳轨诱发瞬时冲击,峰值轮压可达静轮压的10倍,主钩峰值拉力达静拉力的2.5倍,须安装隔震装置避免钢丝绳破断。 相似文献
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The validity and reliability of a portable slip meter for determining floor slipperiness during simulated heel strike 总被引:2,自引:0,他引:2
A previously developed test rig was used as starting point for designing a portable slip meter with two new features. First, an inflatable pneumatic test wheel, consisting of six slider units, was introduced as the impacting contact element relative to floor surface. Second, an inductive trigger was built into the system to facilitate a precise timing of the slider-floor contact during the test. This new test rig was designed to measure transitional friction properties of contaminated floor surfaces during simulated heel strike, which is considered the most critical phase of gait from the slip and fall point of view. Another objective was to quantify the validity and reliability of this test method in the laboratory, but not yet in the field. The measurement process was evaluated on eight wet and oily floor surfaces (vinyl and ceramic tile floorings) using two slider materials (plain, profiled), two normal loads (100, 200 N), and two sliding velocities (0.15, 0.30 m/s) as independent variables. The outputs of the portable slip meter, in terms of transitional friction coefficients, were compared to force platform-based friction values and to slip resistance values obtained with a slip simulator apparatus for laboratory testing of shoes and floor surfaces. The outputs were also evaluated against slipperiness ratings made by three male subjects in paired comparison trials, in which the subjects walked over eight wet floor surfaces wearing shoes with the plain soling material. The results showed that test option 200 N and 0.15m/s led to optimum validity despite its tendency to promote frictional vibrations (stick-slip) in the contact surface. Compared to the lower sliding speed, the higher speed reduced both stick-slip and measurement bias. Test option 200 N and 0.30 m/s was the most reliable one in this experiment. It yielded lower friction coefficients than any other test option and reduced the likelihood of underestimating slip and fall hazards. The results implied that the minimum friction coefficient was 0.25 for preventing a fall on wet floor surfaces, whereas the limit for preventing a slip was in the range 0.30-0.35. Transitional friction measurement was found to be a valid and reliable indicator for slip resistance. A more accurate control of the normal force during testing is needed for actual field use of the test method. 相似文献
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基于本实验室制备的一种炭纤维增强纸基摩擦材料, 研究了固化压力对材料孔隙率, 动摩擦系数, 静动摩擦系数之比, 摩擦力矩曲线的影响。研究结果表明: 孔隙率随固化压力增加而下降; 动摩擦系数随制动压力的增加均呈下降趋势; 静动摩擦系数比值随制动压力的增加分布趋势较为复杂: 较低的固化压力条件下, 静动摩擦系数之比略有上升, 而较高的固化压力条件下静动摩擦系数之比则略有下降趋势; 摩擦力矩曲线随固化压力升高有轻微翘曲出现。综合考虑固化压力对动摩擦系数、 静动摩擦系数比值以及摩擦力矩曲线的影响, 在这种纸基摩擦材料成分不变的条件下, 其对应较为合适的固化压力约为3.4MPa。 相似文献
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Niclas Strmberg 《International journal for numerical methods in engineering》2003,58(15):2371-2385
A method for structural dynamic contact problems with friction and wear is suggested. The method is obtained by including wear in the non‐smooth contact dynamics method of Moreau. A comparison of the method to the discrete energy‐momentum method of Simo and Tarnow is also outlined briefly. The fully discrete equations are treated using the augmented Lagrangian approach, where a non‐smooth Newton method is used as the equation solver. Two two‐dimensional examples are solved by the method. It is investigated how solutions of contact, friction and wear are influenced by inertia. It is shown that the quasi‐static assumption might be questionable for solving contact problems with friction and wear. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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Taking advantage of the magnetic field inside transmission electron microscope(TEM),a unique Lorentz-force-actuated method for quantitative friction tests was developed via a commercial electromechanical holder.With this approach,a submicron-sized silver asperity sliding on a tungsten flat punch was actu-ated by Lorentz force due to electrical current through the punch,with the normal force imposed by the built-in transducer of the holder.The friction force was determined by tracking the elastic deflec-tion of the fabricated cantilever from in situ video.Through correlating the friction behavior with the microstructural evolution near the silver-tungsten interface,we revealed that even when the relative motion commenced with the plastic deformation of the silver asperity,the interface can still sustain the further increasing static friction force.Exactly following the arrival of the maximum static friction force,the sliding occurred at the interface,indicating the transition from static to dynamic friction.This work enriches our understanding of the underlying physics of the dynamic friction process for metallic friction behavior. 相似文献