Geometry design and tooth contact analysis of crossed beveloid gears for marine transmissions

Beveloid gears,also known as conical gears,gain more and more importance in industry practice due to their abilities for power transmission between parallel,intersected and crossed axis.However,this ty...     

考虑轮齿修形的变厚齿轮啮合刚度数值计算

针对有限元法求解变厚齿轮时变啮合刚度的求解效率低、计算结果易不收敛等问题,基于切片法建立了一种考虑齿向修形的变厚齿轮时变啮合刚度求解模型,在综合考虑齿轮基圆与齿根圆之间关系的基础上,对现有的Weber能量法进行改进,并采用该方法计算了变厚齿轮的时变啮合刚度。通过建立变厚齿轮有限元分析模型,对其进行加载接触分析,计算其啮合刚度,并与所提方法进行比较,结果表明,所提方法可以有效提高计算精度,提升计算效率。在此基础上,采用集中参数法分析了变厚齿轮不同啮合参数和修形参数对时变啮合刚度的影响规律,为变厚齿轮的结构优化设计和系统动力学分析奠定了基础。     

Sliding friction effect on dynamics of crossed beveloid gears with small shaft angle

We propose a new method of incorporating the gear sliding friction model and loaded mesh model into an analytical nonlinear crossed beveloid geared vibration model to evaluate the mesh and dynamic characteristics. A 3-dimensional quasi-static loaded tooth contact analysis is employed and the derivation of distributed sliding friction forces and synthesis of frictions to the effective form is applied in the nonlinear dynamic analysis. Using the proposed method, the excitation effects of frictions on tooth mesh and dynamic responses at different load levels are found and investigated. The analysis results show that the existence of sliding frictions between the engaged teeth indeed tends to affect the contact pattern, normal load distribution and maximum contact pressure, but it is unsubstantial. The torque load effect of friction is found with greater degressive influence on mesh stiffness and transmission error at heavier load case. The magnitude and directionality of sliding friction on effective total engaged teeth exhibit less obvious variations than on each tooth due to the contributions from multiple teeth effect. Also, friction excitations tend to decrease the dynamic mesh force slightly for both light and heavy load cases.     

大高变位齿轮传动的动力学分析

针对大变位齿轮真实工况下的动态问题,通过建立齿轮副扭转振动模型研究了大高变位条件下单对齿轮的动力学性能,采用一种准线性的迭代解法求得此非线性方程的数值解,并讨论了变位系数对动载荷、重合度及节点所处位置等的影响.研究结果表明,变位系数大于1时,动载系数全面减小.     

某双离合变速器齿轮的接触应力分析

斜齿轮以传动时冲击噪音小、传动力矩大、传动平稳等特点在汽车变速器中得到广泛应用。利用CATIA软件建立汽车变速器一档齿轮三维实体模型,应用软件HYPERMESH和ABAQUS对变速器一档齿轮进行有限元接触强度分析,得到了一档齿轮在啮合传动过程中,齿面接触线和齿面接触应力的分布情况。结果表明,该款双离合变速器在一档工况下,一档齿轮所受的最大接触应力没有超过材料的许用应力,满足变速器齿轮强度设计的要求。     

直齿轮轮齿刚度的简化计算

直接从轮齿实际形状出发,以相似理论为基础,通过边界元采样计算和回归分析,建立轮齿挠度和啮合刚度计算 方法,全面分析各种轮齿刚度,提出轮齿刚度计算的简化公式,并与ISO6336刚度计算方法进行了对比。     

斜齿圆柱齿轮啮合刚度的一种简化计算

从直齿轮和斜齿轮数学模型的相似性方面入手,提出一种在已知直齿轮啮合刚度的基础上,确定相应斜齿轮啮合刚度的方法。     

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

Gear wear is one of the most common gear failures, which changes the mesh relationship of normal gear. A new mesh relationship caused by gear wear affects meshing excitations, such as mesh stiffness and transmission error, and further increases vibration and noise level. This paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear. A geometric model for a new mesh relationship with gear wear is proposed, which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error (USTE). Based on the mesh stiffness and USTE considering gear wear, a gear dynamic model is established, and the vibration characteristics of gear wear are numerically studied. Comparison with the experimental results verifies the proposed dynamic model based on the new mesh relationship. The numerical and experimental results indicate that gear wear does not change the structure of the spectrum, but it alters the amplitude of the meshing frequencies and their sidebands. Several condition indicators, such as root-mean-square, kurtosis, and first-order meshing frequency amplitude, can be regarded as important bases for judging gear wear state.     

汽车变速箱齿轮可靠性试验数据分布参数估计

采用威布尔分布和混合威布尔分布对影响齿轮传动疲劳寿命的各随机因素进行描述,用最大似然法进行分布参数的估计,并通过最优化方法求得分布参数的最大似然估计值,取得了正确结果.应用表明,这种方法简单实用.     

偏心渐开线齿轮传动的微分模型

偏心渐开线齿轮传动设计的纯滚动模型、等转角模型和等分模型存在模型误差。依据偏心渐开线齿轮传动 的几何关系,建立了偏心渐开线齿轮传动的微分方程,提出了偏心渐开线齿轮传动设计的微分模型。分析了偏心 率与最大传动比的关系,对一些设计和分析参数进行了多项式拟合。运用拟合公式可以快速准确地完成分析和设 计,简化了设计和计算过程。微分模型没有模型误差,微分方程的求解存在舍入误差。     

普通NGWN传动各轮齿数的选配

本文分析了普通ＷＧＷＮ型行星齿轮传动安装条件对各轮齿数的约束，导出新的装配条件表达式。由此提出了新的配齿计算公式和方法，给出了配齿电算程度框图和计算实例，并对机械设计手册中关于ＮＧＷＮ轮系的配齿简化条件进行了讨论。     

封闭齿轮传动效率的实验研究

从实验角度出发 ,且理论与实际相结合 ,指出影响封闭齿轮传动效率的因素     

圆弧齿轮磨损后非稳定传动分析

和相同尺寸的渐开线齿轮相比,圆弧齿轮的当量曲率半径比渐开线齿轮的当量曲率半径大数十倍,因此．圆弧点啮合齿轮副可大幅度提高共轭齿面的接触强度,具有广阔的发展前途。着重对齿轮磨损后的传动性能进行分析．齿面已不能再用原有理想方程表示,只能对磨损后得到的离散点位置坐标值进行双三次样条插值,模拟出磨损后的齿面方程。对变化的瞬时传动比进行分析。     

HXD1C型大功率机车传动系统齿轮的疲劳可靠性分析

基于标准和可靠性曲线,分析了HXD1C大功率机车传动系统齿轮的接触和齿根弯曲疲劳可靠性。结果表明,按照齿轮标准计算方法,齿轮的啮合接触疲劳强度和齿根抗弯强度合格。基于接触和齿根弯曲疲劳可靠性曲线的分析结果表明,在置信度95％及可靠度0．99下,齿轮的抗弯疲劳强度较弱,寿命321．32万公里;在置信度95％及期望寿命80万公里下,传动齿轮的抗弯疲劳强度仍然较弱,可靠度水平为0．9971。     

用AutoCAD绘制齿轮啮合近似轴测图的一种方法

介绍了一种利用AutoCAD绘图软件绘制齿轮啮合关系近似轴测图的方法,实现了简便快捷作图,具有一定的实际意义。     

弧齿锥齿轮几何传动误差的设计与分析

提出基于传动误差设计的概念和方法。通过TCA和LTCA对传动误差曲线的设计进行啮合仿真分析的结果表明 ,根据工作载荷合理地确定传动误差转换点处的幅值与总的幅值 ,可降低弧齿锥齿轮对误差的敏感性 ,可使工作载荷下传动误差波动幅值最小 ,同时可有效地避免或减轻边缘接触。     

圆弧针齿行星传动动力学的计算机仿真

本文建立了双内啮合圆弧针齿少齿差行星传动动力学仿真的数学模型，设计了仿真算法，在微机上完成了对该传动装置的瞬时输出扭矩及瞬时传动效率的模型试验。研究结果表明本文所采用的方法简便有效，结果可靠。为行星传动的计算机辅助设计（ＣＡＤ）提供了一种新方法。     

Upper bound analysis for forging of trochoidal gears

Forging of trochoidal gears has been investigated by means of upper-bound analysis. A kinematically admissible velocity field for forging of a trochoidal gear was proposed. A neutral surface has been used to represent the inward flow of material during forging operation by using a hollow billet with a flat punch. By using the suggested kinematically admissible velocity fields, the applied forces were successfully calculated and compared with experimental inspections. The experimental set-up was installed in a 200-ton hydraulic press for forging. The billets of A1 2218 aluminum alloys were slightly coated with phosphate. It was found that the theoretical solutions were useful to predict the forging load forforging of trochoidal gears.     

矢量原子磁力仪中旋转磁场产生装置的研制

阐述了利用抽运-检测型原子磁力仪研制的磁场旋转调制法矢量原子磁力仪的工作原理、系统组成以及对旋转磁场的技术要求,根据该矢量原子磁力仪对旋转磁场的技术要求,提出了一种高性能旋转磁场产生装置.该装置通过DDS相位同步技术实现了正弦信号间相位差的补偿和精密调控,相位调控精度的理论设计值为0.022°;建立相应的电路模型,通过...     

The design of a stepless transmission using non-circular gears

Non-circular gears can be combined in various ways to make an infinitely-variable transmission of high efficiency. This paper discusses several possible methods and reports results from tests of a prototype transmission.