Discussion on the Free Quenching Heat Treatment Process of Automotive Leaf Springs

Free quenching of automotive leaf springs is a new technology that has gradually started to be applied in the industry in China in recent years.Only a few manufacturers are applying it in the industry.Through more than half a year of on-site practice,the changes in the hot forming of spring plates before free quenching have been explored,and finally a heat treatment process that meets the production requirements of our company has been developed,achieving normal production.

基于Adams的Leaf Spring建模方法及刚度特性仿真测试

文章基于多点离散梁法,通过编写钢板弹簧属性文件,利用Adams/Car模块建立多片钢板弹簧模型,并在Adams/View中对所建多片钢板弹簧作静/动刚度特性仿真测试分析。又分别采用了两种方法对其静/动刚度进行仿真,将仿真结果与实际对比分析,结果表明通过Adams建立的多片钢板弹簧模型与实际钢板弹簧刚度特性基本吻合。

Numerical simulation and optimization of shell mould casting process for leaf spring bracket

Although the shell mould casting process has a wide range of application in many fields,the prediction of casting defects is still a problem.In the present work,a typical leaf spring bracket casting of ZG310-570 was fabricated by shell mold casting.The finite element model and ProCAST software were utilized for simulating the filling and solidification processes of the casting;and the formation mechanism of the gas pore,and shrinkage porosity defects were analyzed.The results indicate that the gas pore and shrinkage porosity defects are formed due to air entrapment,insufficient feeding and non-sequential solidification.Subsequently,through changing the position of risers,adding a connecting channel between the risers,and setting blind risers at the U-shaped brackets,an optimized gating and feeding system was established to improve the quality of the casting.After optimization,the gas pore and shrinkage porosity defects of the leaf spring bracket casting are effectively eliminated.The experiment results with the optimized casting process are in good agreement with the numerical simulation,which verifies the validity of the finite element model in the shell mould casting.

Design and experiment of an adaptive dynamic vibration absorber with smart leaf springs

An adaptive dynamic vibration absorber(ADVA)is designed for lowfrequency vibration suppression.The leaf springs are applied as the tuning stiffness elements.The principle of variable stiffness is analyzed to obtain the effective range of the first natural frequency variation.A classic simply supported manipulator is selected as the controlled system.The coupled dynamic model of the manipulator-ADVA system is built to obtain the maximum damping efficiency and the vibration absorption capacity of the designed ADVA.An experimental platform is set up to verify the theoretical results.It is revealed that the ADVA can adjust the first natural frequency on a large scale by changing the curvature of the leaf springs.The amplitude of the manipulator is reduced obviously with the installation of the designed ADVA.Finally,based on the short-time Fourier transformation(STFT),a stepwise optimization algorithm is proposed to achieve a quick tuning of the natural frequency of the ADVA so that it can always coincide with the frequency of the prime structure.Through the above steps,the intelligent frequency tuning of the ADVA is realized with high vibration absorption performance in a wide frequency range.

Finite element analysis on the static and fatigue characteristics of composite multi-leaf spring

This paper investigated the static and fatigue behaviors of steel and composite multi-leaf spring using the ANSYS V I 2 software. The dimensions of an existing conventional leaf spring of a light commercial vehicle were used. The same dimensions were used to design composite multi-leaf spring for the two materials, E-glass fiber/epoxy and E-glass fiber/vinyl ester, which are of great interest to the transportation industry. Main consideration was given to the effects of material composition and its fiber orientation on the static and fatigue behaviors of leaf spring. The design constraints were bending stresses, deflection and fatigue life. Compared to the steel leaf spring, the designed composite spring has much lower bending stresses and deflections and higher fatigue life cycles.

钢板弹簧建模模块LeafSpring的研究及其应用

LeafSpring是ADAMS中的一个专用模块,应用其可以快速建立钢板弹簧多体动力学模型。为更好应用LeafSpring,总结了其主要特点,分析了其建模基本原理,说明了其建模步骤。应用LeafSpring,在ADAMS/Car中建立了2片簧钢板弹簧多体动力学模型。通过对模型的必要修改,实现了钢板弹簧垂向刚度特性的仿真测试。通过与实际钢板弹簧刚度特性比较,验证了所建模型的有效性。

New ANCF solid-beam element:relationship with Bézier volume and application on leaf spring modeling

An eight-node solid-beam element based on absolute nodal coordinate formulation(ANCF)which uses cubic interpolation at the longitudinal direction and linear at the transverse direction is proposed.The element can accurately discretize the geometry represented by the Bézier volume with the same basis function order.The continuity property of the proposed beam element is verified.Advantages of the proposed element can be found in the application of leaf spring modeling.The parabolically varying thickness of the leaf can be accurately described.Components in leaf spring such as the spring eye and the rubber bushing can be assembled efficiently since the proposed element can be connected at any direction.The ANCF reference node is used to represent the rigid components and the revolute joints in the vehicle suspension system.Static I-shaped cross-section cantilever beam and flexible pendulum model are used to test the accuracy and dynamic performance of the proposed solid-beam element.The leaf spring model shows the flexibility of the element in modeling the complex mechanical system and the balance between the accuracy and the efficiency.

Analytical modeling and simulation on lateral mechanical characteristics of high-speed train traction motor hanging leaf spring

In this paper,using the theoretical analysis method,according to the actual structure of the hanging leaf spring of the traction motor mounted on the frame,the lateral force model of the hanging leaf spring of the traction motor was established.Then,through theoretical deduction,the deformation analytical calculation formula and the stress analytical calculation formula of the hanging leaf spring were established.The correctness of the leaf spring’s lateral force model was established and its deformation and stress analytical formulae were verified using ANSYS finite element analysis software.Based on this,according to the deformation analytical formula and the stress analytical formula of the leaf spring established,the influence of the main structural parameters on the mechanical characteristics of the leaf spring was discussed,and the reliability of the analytical analysis method of the lateral mechanical characteristics of the traction motor hanging leaf spring was verified by the loading–unloading test.The results show that the deformation and the load of the leaf spring change linearly.The changes of leaf spring’s stress at different positions can be considered as being composed of three sections:a linear change section in the root,a nonlinear change section in the middle,and a nonlinear change section in the end.In the structural parameters,the end thickness h2 has the greatest influence on the stiffness and the stress of the leaf spring,and the maximum thickness of the leaf spring eye h1 has the least influence on the stiffness and the stress of the leaf spring.The influence degree of other parameters on the stiffness of the leaf spring is h_(3),L_(1),L_(3),L_(2) in order,and the influence degree on the stress of the leaf spring is h_(3),L_(1),L_(2),L_(3) in order.In addition,when the root thickness h_(3) is greater than a certain value,the maximum stress point of the leaf spring appears at the end position L_(2).This study can provide a useful reference for the intelligent forward design and the rapid analysis of the mechanical characteristics of high-speed train traction motor hanging leaf spring.

A Design Method of Bending Deflection on Hyper-Static Leaf Spring

A group of leaf springs which provides the flexible support of stator is designed to satisfy the requirement of low vibration motor at megawatt （MW） level. Spring steel 65Mn is chosen as the material of the leaf spring. The size of the leaf spring is obtained by calculation and load analysis according to a deflection formula. The deflection and stiffness of the single leaf spring is calculated with both theoretical method and finite element analysis （FEA）. A deflection test platform is established based on actual force and boundary condition to verify the deflection and stiffness of the leaf spring. The results show that the maximal deflection of the three pieces of 1.2 mm leaf spring group is 0.71 mm and the stiffness of the leaf spring group is 364 N/mm, which satisfies the requirements of the motor. The design method is also applicable for other MW power level motors.

Design and Analysis of a 2-DOF Actuator with Variable Stiffness Based on Leaf Springs

Variable Stiffness Actuator(VSA)is the core mechanism to achieve physical human–robot interaction,which is an inevitable development trend in robotic.The existing variable stiffness actuators are basically single degree-of-freedom(DOF)rotating joints,which are achieving multi-DOF motion by cascades and resulting in complex robot body structures.In this paper,an integrated 2-DOF actuator with variable stiffness is proposed,which could be used for bionic wrist joints or shoulder joints.The 2-DOF motion is coupling in one universal joint,which is different from the way of single DOF actuators cascade.Based on the 2-DOF orthogonal motion generated by the spherical wrist parallel mechanism,the stiffness could be adjusted by varying the effective length of the springs,which is uniformly distributed in the variable stiffness unit.The variable stiffness principle,the model design,and theoretical analysis of the VSA are discussed in this work.The independence of adjusting the equilibrium position and stiffness of the actuator is validated by experiments.The results show that the measured actuator characteristics are sufficiently matched the theoretical values.In the future,VSA could be used in biped robot or robotic arm,ensuring the safety of human–robot interaction.

圆弧叶形弹簧的大变形分析

目的通过对圆弧叶形弹簧缓冲器非线性大变形特性的研究,为其缓冲设计与应用提供理论参考。方法基于Euler-Bernoulli梁理论,以叶形弹簧的初始圆弧半径及截面角为基本参数推导弹簧的大变形控制方程,考虑压板作用下弹簧的多种变形情况给出圆弧叶形弹簧变形的边界条件,进而利用两点边值问题的数值解法计算不同顶角的叶形弹簧在外力作用下的变形情况。结果理论计算结果与数值解高度吻合,表明了计算方法的可靠性,计算得到了不同压力下叶形弹簧变形后的位形图及弹簧的非线性力-变形曲线。结论所讨论的叶形弹簧具有明显的非线性大变形特性和良好的减震及缓冲吸能特性,能够较好地替代传统缓冲材料用于运输系统的缓冲设计。

不同剪梢程度对农桑14号春季经济性状及产叶量构成的影响

[目的]分析不同剪梢程度对农桑14号春季经济性状和桑叶产量及其构成的影响,为农桑14号的春季剪梢提供技术参考。[方法]对桑树枝条进行1/4、1/3、1/2剪梢处理,调查不同处理的发育历期、止芯芽性状、生长芽性状、枝条长度及桑叶产量表现。[结果]在发育时间上,剪梢1/4、1/3与剪梢1/2的处理从膨芽期到雀口期,发育历期呈增大趋势;在开叶阶段,发育历期呈缩短趋势;到桑叶成熟期,发育历期呈增大趋势。在桑叶产量及其构成上,剪梢1/4处理平均产量2.413 kg/株,其中生长芽叶重2.068 kg/株,占85.70%,止芯芽叶重0.345 kg/株,占14.30%;剪梢1/3处理平均产量3.042 kg/株,其中生长芽叶重2.612 kg/株,占85.86%,止芯芽叶重0.345 kg/株,占11.34%;剪梢1/2处理平均产量2.172 kg/株,其中生长芽叶重1.875 kg/株,占86.33%,止芯芽叶重0.297 kg/株,占13.67%。[结论]采用1/4或1/3剪梢处理,大蚕用叶可提前到4月28日,且桑叶产量高于1/2剪梢处理,对全年多批次养蚕的时间调控和桑叶保障更加有利。

汽车钢板弹簧悬架装配工艺研究

悬架系统是汽车的重要组成部分,其性能对汽车行驶平顺性,操纵稳定性和安全性都有着重要的影响。悬架承受和传递载荷,工况复杂,正确的装配是悬架系统工作的前提。文章以商用车钢板弹簧悬架为对象,结合企业生产实践,探讨悬架装配工序划分、装配工装、装配工艺过程、装配质量管理等内容。

某轻型客车钢板弹簧断裂失效原因分析

某轻型客车钢板弹簧在整车耐久试验过程中频繁出现断裂问题。文章通过断口宏观和微观分析、化学成分分析、硬度测试、金相组织检测分析,以及铣削台阶位置和板簧受力特征分析,确定了钢板弹簧断裂的根本原因并制定了改进措施,结合台架试验及整车道路试验进行了验证。结果显示,钢板弹簧卷耳两侧铣削范围过长,导致板簧簧片R角处存铣削台阶,使得此处应力集中进一步提高,导致钢板弹簧在此处断裂。减小钢板弹簧卷耳两侧铣削长度,问题得以解决。

新型弧形板簧支撑非充气轮胎的有限元分析

设计一种以弧形等厚板簧为主要承载部件的新型非充气轮胎,建立其有限元模型,仿真模拟静态径向加载与稳态纯滚动工况,得出轮胎径向刚度和径向力,对接地压力参数进行评价,计算出轮胎有效滚动半径。结果表明:在静态径向加载条件下,轮胎径向力与径向位移近似线性正相关,径向刚度和径向力随板簧厚度增大而增大;轮胎接地印痕中心出现应力集中现象,板簧越厚则平均接地压力越大,胎面不均匀磨损程度越高;轮胎有效滚动半径随径向负荷增大线性减小。本研究可为非充气轮胎性能分析或者结构优化提供参考。

矿用宽体车互联式油气悬架系统平顺性分析

采用钢板弹簧悬架的矿用宽体车难以获得良好的行驶平顺性,为此,提出了一种刚度阻尼可调的互联式油气悬架系统。首先,阐述了互联式油气悬架系统的工作原理,建立了油气悬架系统的数学模型;其次,运用AMESim软件搭建了互联式油气悬架系统和钢板弹簧悬架的仿真模型,确定了仿真模型中的主要参数;最后,在D级随机路面激励下进行了匀速和加速-制动运行工况的车辆行驶平顺性仿真研究,并对仿真结果进行了分析。研究结果表明:与钢板弹簧悬架相比,匀速和加速-制动的空载工况下,互联式油气悬架系统的车身加速度均方根值分别下降了38.7%和38.8%,车轮动载荷均方根值分别增加了3.1%和0.5%,不影响车轮的接地性,悬架动挠度均方根值分别增加了41.6%和39.7%,悬架撞击限位块的概率小于0.1%,满足设计要求;匀速和加速-制动的满载工况下,互联式油气悬架系统的车身加速度、车轮动载荷、悬架动挠度三项平顺性评价指标均得到改善。该结果证明互联式油气悬架系统可提升车辆的行驶平顺性,为矿用宽体车油气悬架系统设计提供参考。

某房车用少片簧断裂原因

在对某房车进行可靠性路试过程中,其少片簧发生断裂现象。采用宏观观察、化学成分分析、硬度测试、金相检验、扫描电镜分析等方法对少片簧断裂的原因进行分析。结果表明:少片簧表面存在局部折叠,在路试过程中,其表面产生了应力集中,使裂纹萌生并扩展,最终导致少片簧断裂。

磁机械振荡器模型的弹簧片运动参数探究

针对磁机械振荡器模型中弹簧片在磁场中不断振荡的现象,利用Hook定律和电磁学基本相互作用关系式,对弹簧片建立二维动力学理论模型、构建二阶常微分方程,得到弹簧片振幅和能量的影响因素。通过控制单一变量法进行实验探究,以及利用Tracker软件对实验视频逐帧追踪分析,结合Matlab仿真,将实验结果与理论进行对比分析,五组实验的平均相对误差分别为3.21、1.83、2.67、1.98和2.36%,为磁机械振荡器的相关研究提供了理论支撑和实验方法。

某商用车钢板弹簧失效分析与结构优化

为解决某商用车钢板弹簧断裂问题,分别从板簧材质、成型工艺、结构设计强度多方面进行失效分析,考虑不同工况场景的载荷特点,建立板簧的非线性仿真模型。根据整车冲击工况加载标准,提取各工况下的板簧应力。建立板簧总成的详细模型,以提取的板簧应力为载荷,考察板簧及桥壳底板的可靠性,从而确定薄弱部位与断裂原因。以主簧的簧片厚度为设计变量,以板簧的结构应力为约束条件,以总质量最小为约束目标,对板簧进行尺寸优化,寻找满足应力要求的簧片最小厚度。对优化后的主、副簧进行疲劳耐久试验,验证仿真结果的准确性。

工程车平衡悬架钢板弹簧座疲劳断裂机理研究

为解决某工程车平衡悬架钢板弹簧座失效断裂问题,利用工艺分析、断口分析、金相检验、强度检测、硬度检测以及材料疲劳极限检测等方法,对平衡悬架钢板弹簧座进行分析。结果表明:平衡悬架钢板弹簧座所用材料满足标准要求,平衡悬架钢板弹簧座的失效形式为多源高应力、低周次弯曲疲劳开裂,裂纹源处于平衡悬架钢板弹簧座与U型螺栓配合的圆角根部位置,该位置较厚大在生产工艺上易产生缩孔缩松等缺陷,在结构上是平衡悬架钢板弹簧座承受应力最大的位置,为零件的危险截面。