制冷线性压缩机盘簧研究

弹簧是实现线性压缩机活塞共振控制和影响压缩机寿命的关键零件,针对现有压缩机用板弹簧刚度小、使用数量多等问题,设计了一种多臂阿基米德螺线盘簧,采用有限元法分析了阿基米德螺线的基圆半径r、略角θ、螺距常数b等参数对弹簧臂刚度的影响规律,针对盘簧臂刚度的多因素影响特性,采用有限元响应面优化法,对圆柱盘簧臂的刚度性能进行了优化,优化后的圆柱盘簧臂的轴向刚度提高了42.5%,径向刚度提高了26.8%,且疲劳强度满足使用要求;对两臂和三臂盘簧进行了刚度测试实验,并对两者的性能进行分析和对比,得出了在同等轴向刚度条件下,三臂盘簧径向刚度和质量特性要优于两臂盘簧,将三臂盘簧应用于线性压缩机中,可以替代6个板弹簧,轴向刚度可达到25.6N/mm,且具有较好的径向支撑效果,能够满足线性压缩机所需要的轴向刚度以及径向刚度需求,研究结果对线性压缩机弹簧的设计和应用具有理论和实际意义。     

制冷线性压缩机弹簧组件的设计与研究

为减小弹簧组件体积并满足制冷线性压缩机的刚度需求,设计出一种基于阿基米德螺线的圆柱臂盘簧.采用有限元分析方法对涡旋臂板弹簧和新型圆柱臂盘簧的径向与轴向的刚度变化、应力变化特性和等效质量进行了分析对比,对两种弹簧的轴向刚度特性进行了实验验证,并将新型圆柱臂盘簧用于弹簧组件.研究结果表明,圆柱臂盘簧具有较大的径向刚度和轴向...     

自由活塞斯特林制冷机中静压气体轴承的探讨

现代长寿命特林制冷机几乎都采用间隙密封、直线电机驱动和柔性板弹簧支撑技术,特别是还采用静压气体轴承以弥补柔性板弹簧刚度不足的缺点,消除摩擦,提高其寿命。本文分析了长寿命自由活塞斯特林制冷机中静压气体轴承的结构和性能影响因素以及其对制冷机性能的影响,为以后的研究提供帮助。最后,提出了以后的研究方向和重点。     

几何参数对微型压缩机柔性板弹簧性能影响

板弹簧技术是线性压缩机驱动的微型斯特林制冷机长寿命、高可靠运行的关键技术之一.本文中设计了3款不同形式的微型压缩机用柔性板弹簧,并基于有限元法展开了不同板簧厚度、涡旋槽宽度、涡旋臂数目这3个几何参数对板弹簧性能的影响分析,最后总结出几何参数对板弹簧性能影响规律.     

干涉式大气垂直探测仪中面弹簧的有限元分析

面弹簧是干涉式大气垂直探测仪中的精密部件,系统要求其在工作过程中具有较大刚度比和足够的轴向行程。利用有限元分析方法对面弹簧进行了优化设计。通过对比不同缝形面弹簧在轴向拉伸过程中的轴向刚度、径向刚度、刚度比,确定了螺旋缝形是相对最优缝形。进一步对螺旋缝形面弹簧做了系统分析,得到了螺旋缝形面弹簧中的基圆半径 、螺距 、旋转角度 、指数 、直径 、开缝数 、簧片厚度 、材料的杨氏模量等参数在面弹簧轴向拉伸过程中,对其轴向刚度、径向刚度、刚度比的影响规律。根据有限元分析结果最终确定一组最优参数值 r₀=20mm,a=20／π²mm/rad,θ₁=πrad,b=2,=200mm,n=3,t=0.2mm,E=1.3 e11Pa,并据此加工成实物。对实物的实测结果表明,螺旋缝形面弹簧具有的轴向行程和较大的刚度比达到了设计目标,验证了有限元分析结果的准确性和合理性。     

基于刚度性能的机器人臂长优化

基于机器人静刚度模型,分析如何通过机器人臂长及位形优化提高机器人刚度。首先,在机器人典型传动部件刚度计算的基础上,分析刚度矩阵的最小奇异值,将之作为评价机器人静刚度性能的指标。然后,为了衡量机器人在整个工作空间中刚度性能的平均水平,提出采用刚度全域性能指标,并以之作为目标函数对机器人臂杆长度进行优化。最后,以本实验室开发的SCARA机器人为例,展示了优化方法的应用及其效果。     

O形线性缓冲器有限元分析与应用

针对一类无法使用液压或橡胶缓冲器的机械冲击场合,提出采用一种线性特性好、体积小、刚度高并且结构简单的O形弹簧代替普通机械弹簧做缓冲器.分析缓冲器机构的动力学模型,并就O形弹簧与普通圆柱螺旋弹簧、碟形弹簧的性能进行对比分析.结果表明,O形弹簧具有体积小刚度大的特点.建立O形缓冲器有限元力学分析模型,对不同几何尺寸的缓冲器的静载强度和屈服极限进行数值分析,并使用TableCurve 3D软件对结果做数值分析,得出缓冲器几何尺寸与弹簧刚度之间的关系.结果表明,增加O形线性缓冲器刚度的最有效方法是增加缓冲器壁厚,而不是增加缓冲器宽度或减少缓冲器外直径.对比有限元仿真结果与试验结果,两者吻合较好,证明了有限元方法的有效性.     

基于有限元和响应面法的U形弹簧结构参数分析

液压作动器内部密封件的蓄能性能是衡量其可靠性的关键,而U形弹簧作为蓄能密封圈的弹性元件,其压缩刚度和弹性压缩极限是决定其蓄能性能的主要因素。建立基于材料参数的U形弹簧弹塑性有限元模型,计算U形弹簧的压缩刚度、弹性压缩极限和线性压缩临界值,分析典型结构参数对蓄能特性的影响;基于响应面法构建多因素数学模型,比较各结构参数对弹簧压缩刚度和弹性压缩极限的影响程度;通过多次弹簧压缩试验验证了计算模型的准确性。结果表明：弹簧厚度、截面总长、开槽宽度、周期宽度和根部圆弧半径为压缩刚度的主要影响因素,其影响依次减小;弹簧厚度、截面总长和根部弧半径为弹性压缩极限的主要影响因素,其影响依次减小。重复压缩试验证明,弹簧屈服产生的塑性变形会随着压缩次数累加,导致弹簧开口宽度减小,导致密封圈动态密封性能降低;当蓄能密封圈用于动密封时其压缩量不宜超过弹性压缩极限。     

一种基于电磁弹簧的智能减振器设计与研究

针对现有参数可调式减振器结构的不足之处,设计了一种基于电磁弹簧的智能减振器,该减振器采用动力吸振器原理,可通过自主调节自身频率以适应多种工况.首先,设计了一种新型的电磁弹簧结构,通过仿真优化了电磁弹簧的结构,确定了电磁弹簧模型;然后,基于该电磁弹簧模型,设计了一种刚度可调的智能减振器装置,并对该智能减振器装置的减振性能...     

汽车悬架控制臂多目标拓扑优化设计

为了实现悬架控制臂的轻量化,利用动力学分析软件对控制臂三种典型工况进行模拟路试,提取关键硬点的载荷作为边界条件,采用折衷规划法建立综合目标函数,运用灰色关联分析法分配各工况权重系数,对悬架控制臂进行拓扑优化;根据拓扑优化的结果对控制臂进行二次设计.分析结果表明,改进后的控制臂的刚度和强度性能均能满足要求,控制臂减重16.5％,实现了轻量化的目的.     

Dynamic optimization of robot arm based on flexible multi-body model

This paper examines the effect mechanism of torsional stiffness on flexible joints and the dynamic optimization of a six Degree-of-freedom industrial robot arm. The design optimization of the robot arm is investigated based on the rotor-torsional spring model and finite element method. The flexible multi-body dynamic model of the robot arm are established by considering the flexible characteristics of arms and joints, and the natural frequencies of a robot arm are calculated to obtain the torsional stiffness of the flexible joints. Natural frequency results gradually increased with joint stiffness improvement. Using the established dynamic model, the topology optimization on the robot arm is carried out by regarding lightweight as design goal and total displacement as constraints. The tare-load ratio and dynamic performance of the optimized robot arm are significantly enhanced compared with the original design model. This research can provide the theoretical basis for the dynamic optimization and upgrade of lightweight robot arm.     

基于柔性多体动力学的机械臂结构优化设计

针对柔性关节对工业机器人动力学特性的影响,基于“转子-扭簧”模型和有限元法,研究关节刚度对机械臂固有动力学特性的影响规律;考虑臂杆柔性和关节柔性,建立了机械臂多柔体动力学有限元模型,以机械臂轻量化为设计目标,以末端总位移量为约束条件对机械臂结构进行优化。研究结果表明,不同关节刚度对机械臂各阶固有频率的影响不同,优化后的机械臂载重/自重比增大,刚度和强度均得到提高,整体动力学性能明显提高。     

火箭炮平衡悬架钢板弹簧三连杆模型研究

以远程多管火箭炮平衡悬架钢板弹簧为研究对象,利用ABAQUS软件建立了有限元模型,得到了钢板弹簧刚度特性。为便于研究远程多管火箭炮的平顺性能,将钢板弹簧简化为三连杆模型,通过Isight集成优化法与逆向仿真法对三连杆模型参数进行辨识,建立了准确的三连杆模型。利用ADAMS对三连杆模型进行仿真计算,并与有限元结果对比,验证了模型的准确性。     

扭杆弹簧计算与优化

扭杆弹簧是车辆悬架装置中常用的弹性元件。文中利用有限元方法对扭杆弹簧进行了建模和优化计算。给出了扭杆弹簧的优化参数和结构应力分布规律，并对优化结果进行了实验测试与比较。分析结果表明，扭杆弹簧过渡区的结构对其应力分布具有较大影响，通过优化设计改进扭杆弹簧结构，有利于提高其性能。     

渐变刚度钢板弹簧的非线性有限元分析

针对传统的钢板弹簧设计计算方法难以考虑钢板弹簧实际的工作状况,综合考虑钢板弹簧实际工作过程中的大变形、各簧片及垫片之间的接触和摩擦等非线性因素,基于有限元分析方法对某汽车后悬架渐变刚度钢板弹簧的刚度及强度特性进行分析。其刚度及强度试验结果表明,考虑非线性因素后建立的钢板弹簧有限元模型精度比较高。在模型验证精确的基础上,利用瞬态动力学分析方法求解钢板弹簧在简谐载荷激励下的动态响应,获得其动态特性随激励载荷频率与幅值的变化规律。该建模方法能有效地模拟钢板弹簧实际工作状态,可为钢板弹簧结构进一步的优化提供前提。     

New nonlinear stiffness actuator with predefined torque‒deflection profile

A nonlinear stiffness actuator (NSA) could achieve high torque/force resolution in low stiffness range and high bandwidth in high stiffness range, both of which are beneficial for physical interaction between a robot and the environment. Currently, most of NSAs are complex and hardly used for engineering. In this paper, oriented to engineering applications, a new simple NSA was proposed, mainly including leaf springs and especially designed cams, which could perform a predefined relationship between torque and deflection. The new NSA has a compact structure, and it is lightweight, both of which are also beneficial for its practical application. An analytical methodology that maps the predefined relationship between torque and deflection to the profile of the cam was developed. The optimal parameters of the structure were given by analyzing the weight of the NSA and the mechanic characteristic of the leaf spring. Though sliding friction force is inevitable because no rollers were used in the cam-based mechanism, the sliding displacement between the cam and the leaf spring is very small, and consumption of sliding friction force is very low. Simulations of different torque‒deflection profiles were carried out to verify the accuracy and applicability of performing predefined torque‒deflection profiles. Three kinds of prototype experiments, including verification experiment of the predefined torque‒deflection profile, torque tracking experiment, and position tracking experiment under different loads, were conducted. The results prove the accuracy of performing the predefined torque‒deflection profile, the tracking performance, and the interactive performance of the new NSA.     

An assumed mode method and finite element method investigation of the coupled vibration in a flexible-disk rotor system with lacing wires

The Assumed mode method (AMM) and Finite element method (FEM) were used. Their results were compared to investigate the coupled shaft-torsion, disk-transverse, and blade-bending vibrations in a flexible-disk rotor system. The blades were grouped with a spring. The flexible-disk rotor system was divided into three modes of coupled vibrations: Shaft-disk-blade, disk-blade, and blade-blade. Two new modes of coupled vibrations were introduced, namely, lacing wires-blade and lacing wires-disk-blade. The patterns of change of the natural frequencies and mode shapes of the system were discussed. The results showed the following: first, mode shapes and natural frequencies varied, and the results of the AMM and FEM differed; second, numerical calculation results showed three influencing factors on natural frequencies, namely, the lacing wire constant, the lacing wire location, and the flexible disk; lastly, the flexible disk could affect the stability of the system as reflected in the effect of the rotational speed.     

基于粒子群算法的汽车悬架弹簧的优化设计

粒子群算法容易理解、易于实现、编程简单。利用粒子群优化算法对汽车悬架弹簧进行优化设计,其速度要比用其他的方法快得多,仅迭代很少的次数就能得出比较优的结果。有利于提高设计的速度,使设计易于实现,更大程度地提高设计的质量,为钢板弹簧系统、汽车悬架和整车的分析计算奠定坚实的基础。同时为少片弹簧和多片弹簧的优化设计提供了一种新的方法。     

Design of an adjustable-stiffness spring: Mathematical modeling and simulation, fabrication and experimental validation

An adjustable-stiffness actuator composed of two antagonistic non-linear springs is proposed in this paper. The elastic device consists of two pairs of leaf springs working in bending conditions under large displacements. Owing to this geometric non-linearity, the global stiffness of the actuator can be adjusted by modifying the shape of the leaf springs. A mathematical model has been developed in order to predict the mechanical behavior of our proposal. The non-linear differential equation derived from the model is solved, obtaining large stiffness variations. A prototype of the actuator was fabricated and tested for different load cases. Experimental results were compared with numerical simulations for model verification, showing excellent agreement for a wide range of work.