共查询到19条相似文献,搜索用时 140 毫秒
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《机械传动》2016,(11):16-19
曲线张紧是汽车发动机正时链系统的常见约束方式,其布局设计直接关系到正时链系统的振动特性、噪声特性、平顺特性。通过某款发动机正时齿形链系统设计实例,解析了三轴系统的链条张力特点,并进行了张紧器的张紧力与松边张力的定量描述。通过缸盖反拖系统试验台测试了不同转速条件下的张紧力,以及特定转速的曲轴转矩,得到了正时链系统的载荷循环特性。结果表明,在保证正时链系统动力性能的基础上,张紧约束应综合考虑吸纳正时链的磨损伸长,以及张紧力的施力方向,还要兼顾正时链的静强度安全裕度。研究结论对链条在汽车发动机中的应用具有重要意义,同时对多轴系的链传动系统设计也具有一定的借鉴作用。 相似文献
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张紧器是发动机正时链系统的关键部件,安装在链条的松边,起到张紧链条的作用。张紧器是一个典型的弹簧阻尼系统,阻尼油腔依赖于发动机润滑系统供油,如果供油不足,油腔中吸入空气,张紧器就会发软。发软的张紧器不仅会产生敲击噪音,而且会引起系统振动冲击从而损伤相关部件。因此张紧器机油供应量必须根据具体的应用进行设计。本文通过正时系统的受力分析得到张紧器柱塞波动幅值和机油需求量。分析发现张紧器柱塞波动幅值与转速成反比,因此低速时柱塞波动幅值最大。在本例中,发动机转速越低,张紧器需要的机油流量越大。低转速时润滑油供应设计应该特别关注张紧器的机油需求量。 相似文献
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为测试滚子链的耐久性、使用寿命等性能,基于功率流封闭原理,为滚子链条磨损跑合试验设计了一套自动试验台。采用链轮错齿法,通过计算机控制张紧及夹持装置,对被试链条和陪试链条进行转矩加载,实现试验系统功率流封闭。为实现该试验台自动张紧和夹持功能,设计了液压及计算机测控系统,为满足不同型号链条的试验条件,对所需张紧油缸和夹持油缸进行了设计选型。通过零件加工和购买所需元件,搭建了试验台样机,并利用其对滚子链进行磨损跑合试验,结果表明,其能满足不同型号的滚子链试验条件,且能耗低,运行可靠。 相似文献
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This paper presents the design of a novel kinematic tensioning system to remedy the situation where the input-output relation in the cable transmission for a remotely operated multi-link end-effector is compromised due to the onset of slack. The actuation of multi-link end-effectors in remote manipulators via cable transmission exhibits loss of tension and slack generation on the non-driving side of the cable transmission. This paper outlines an analytical formulation of the kinematic component of slack resulting from the geometry of the end-effector links that are serially connected. If left unaddressed, cable slack adversely impacts transmission stiffness and produces backlash at the end-effector wherein for a fixed input, the output can move freely over a range of motion (i.e. dead-band). In case of articulating instruments for minimally invasive surgery, this limits the ability to position and orient the end-effector precisely, the ability to effectively transmit forces via the end-effectors to the surrounding tissues, and the tactile feedback to the user operating the instrument. To overcome these limitations, this paper presents a simple solution that effectively mitigates slack on the non-driving side of a cable transmission between a driving pulley and a multi-link end-effector with minimal cost or complexity. The proposed design uses a driving pulley modified with tensioner extensions to alter the transmission path, which provides a kinematic or geometric solution in contrast to the various spring based solutions that have several drawbacks. Based on a derivation of slack in the system, a design optimization is performed to generate the key dimensions of the tensioning system that minimizes slack without causing over-constraint. An experimental setup is designed and fabricated to validate the slack predictions in the cable transmission system for a multi-link end-effector, without and with the proposed tensioner. The experimental measurements demonstrate the efficacy of the proposed solution. 相似文献
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Dynamic Modeling of a Roller Chain Drive System Considering the Flexibility of Input Shaft 总被引:1,自引:0,他引:1
Roller chain drives are widely used in various high-speed, high-load and power transmission applications, but their complex dynamic behavior is not well researched. Most studies were only focused on the analysis of the vibration of chain tight span, and in these models, many factors are neglected. In this paper, a mathematical model is developed to calculate the dynamic response of a roller chain drive working at constant or variable speed condition. In the model, the complete chain transmission with two sprockets and the necessary tight and slack spans is used. The effect of the flexibility of input shaft on dynamic response of the chain system is taken into account, as well as the elastic deformation in the chain, the inertial forces, the gravity and the torque on driven shaft. The nonlinear equations of movement are derived from using Lagrange equations and solved numerically. Given the center distance and the two initial position angles of teeth on driving and driven sprockets corresponding to the first seating roller on each side of the tight span, dynamics of any roller chain drive with two sprockets and two spans can be analyzed by the procedure. Finally, a numerical example is given and the validity of the procedure developed is demonstrated by analyzing the dynamic behavior of a typical roller chain drive. The model can well simulate the transverse and longitudinal vibration of the chain spans and the torsional vibration of the sprockets. This study can provide an effective method for the analysis of the dynamic characteristics of all the chain drive systems. 相似文献
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阐述了正时链系统在汽车发动机上应用的特点,介绍了汽车发动机正时链的分类及其服役工况,预测了汽车发动机正时链系统的国内外市场需求,分析了国内汽车发动机正时链系统的研发状况及其发展趋势,展望了全面实现我国汽车链传动国产化的前景. 相似文献
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探讨了非圆链轮传动中,具有最小理论松弛量时,链轮节曲线的综合,建立了相应的数学模型,并通过C语言编程进行了实例分析,得出了基于最小理论松弛量时的最佳非圆链轮节曲线。 相似文献
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网络化制造资源集成共享与优化配置主要包括协同制造总任务的分解、单任务驱动的制造资源的评价选择、时序约束关联单任务链驱动制造资源链的构建三个阶段。首先根据协同制造总任务分解的特点,提出了跨组织协同制造任务分解过程模型和相应的分解算法。然后提出了单任务约束驱动网络化制造资源评价指标体系与评价算法,在此基础上对单任务驱动检索的候选资源集,提出了基于改进蚁群算法的时序约束关联单任务链驱动网络化制造资源服务链构建模型与算法。最后通过仿真算例说明了研究成果的有效性。 相似文献
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提出了正时系统设计时所要考虑的边界条件,给出了正时链条的伸长量与活动导板转角变化关系的解析表达式、张紧器柱塞行程与安装位置的计算、活动导板轮廓及安装位置的优化设计等正时链系统总体优化设计计算方法。实验结果表明,这种方法是科学的,是切实可行的。 相似文献