人字齿轮星型传动系统优化修形设计

齿轮修形是改善齿轮传动动态特性的一种重要手段。应用人字齿轮于星型轮系构成人字齿轮星型传动系统,研究了修形齿面建模和承载传动误差计算方法。以承载传动误差幅值最小为目标,分别进行了太阳轮与星轮啮合副和星轮与内齿圈啮合副修形优化设计。将优化设计得到的修形量重新分配,并通过TCA和LTCA技术验证了分配方法合理性。该研究成果为星型轮系修形设计提供了理论依据。     

直齿轮传动多工况多目标修形优化设计

针对直齿轮多工况使用情况,研究了小轮修形齿面理论建模方法和直齿轮传动多工况多目标修形优化方法,进行了两种工况下直齿轮传动多工况多目标修形优化设计,并进行了修形和不修形齿轮的齿面啮合仿真,通过对比分析,验证了齿面优化修形后达到了较好的综合性能,两种工况下的承载传动误差波动幅值和最大闪温均明显下降.研究成果为提高直齿轮综合性能的修形设计奠定了基础.     

平动齿轮传动啮合效率的理论研究

基于效率的定义研究了平动齿轮传动啮合效率.针对平动齿轮的运动特点,分别对啮合点位于节点前与节点后时内、外平动齿轮增速与减速传动的啮合效率函数进行了推导,并证明了其在整个啮合区间上的连续性.利用连续函数的积分中值定理,分别推导出了节点内啮合与节点外啮合的内、外平动齿轮增速与减速传动啮合效率计算公式,并证明了其正确性,为平动齿轮传动装置的效率设计与预测提供了依据.通过实例得出平动齿轮增速及减速传动具有很高啮合效率的结论.     

摆线针轮传动啮合力计算及有限元分析

计算了修形前后摆线齿轮与针齿的啮合作用力,通过初始间隙的分布曲线判定了修形摆线齿轮与针齿的同时啮合齿数。建立了摆线齿轮及针齿的参数化模型,并导入到ANSYS软件当中,建立了以"接触单元密分和非接触单元粗分"为原则的有限元模型,分别对标准齿形摆线齿轮及修形摆线齿轮的啮合作用力进行了有限元接触应力分析,得到了考虑摩擦因数的最大啮合作用力,并与通过理论公式计算出的最大啮合作用力进行对比分析。研究结果可为工程上摆线针轮传动的受力分析提供理论依据和技术支持。     

双圆弧齿轮传动的边界效应和齿向修形

根据双圆弧齿轮传动的啮合特性,在Pro/E参数化建模的基础上,应用有限元方法研究了某双圆弧齿轮传动在啮合周期和啮合过程中等效应力沿齿向的分布规律,指出双圆弧齿轮传动啮合过程出现端面边界效应的啮合状态与位置,并针对端面边界效应进行齿向修形。有限元分析证明了齿向修形可有效避免双圆弧齿轮传动的边界效应及其所产生的应力集中,为提高双圆弧齿轮疲劳寿命提供了一种有效的措施.     

高变位齿轮的修形研究

针对海洋钻井平台减速器高变位齿轮在低速重载工况中存在啮合冲击大、齿面容易胶合、传动噪音大的问题,选取了减速箱高速级一对齿轮副进行了分析建模,通过改变齿形参数对齿轮在抗胶合安全系数、轮齿啮合质量和传递误差进行了研究,提高了齿轮的传动质量,采用合理的修形参数和修形方法对齿轮各方面参数进行了研究和测试,最后对修形前、后齿轮强度等参数进行了对比分析。研究结果表明,通过合理的修形设计,能够改善齿轮啮合质量,提高齿轮的抗胶合能力,降低齿轮传动误差和噪声,这对低速重载齿轮修形在实际工程上的应用提供了参考依据。     

风电增速齿轮系统接触动力学建模与分析

用参数化设计方法精确地建立风电增速齿轮模型,并根据风电增速齿轮副的承载和结构特点,建立了风电增速齿轮三维有限元模型,对风电增速齿轮啮合传动进行接触动力学分析,由瞬态动力学模拟计算得到了齿轮副在啮合过程中不同时刻的齿面接触应力、齿根弯曲应力等变化情况,并对增速齿轮在啮合传动过程中齿根应力、轮齿啮合应力和齿宽方向应力的变化趋势进行了较为详细的分析,进而为风电增速齿轮的优化设计和分析提供了有效的理论依据。     

弧线齿圆柱齿轮四阶传动误差设计与分析

为了改善弧线齿圆柱齿轮传动的平稳性和轮齿强度,采用四阶传动误差曲线设计齿轮副。首先确定四阶传动误差曲线的系数,用有具有刀倾的刀盘形成的弧线产形齿条和假想小轮的方法,根据坐标变换和啮合方程,分别推导大轮和小轮的齿面方程。由两齿面在啮合中的连续相切条件,建立了考虑安装误差的轮齿接触分析(TCA)模型。齿轮副啮合仿真的结果表明,该方法可实现四阶传动误差,增大啮合转换点处夹角可使齿轮副平稳过渡,减小齿根的修形量可提高轮齿强度,可降低传动误差曲线对安装误差的敏感性。     

小角度相交轴渐开线圆柱与变厚齿轮传动修形啮合特性分析

推导了考虑齿向修形与齿廓修形条件下的渐开线变厚齿轮齿面数学方程,采用有限元法建立了相交轴渐开线圆柱与变厚齿轮副有限元啮合模型,研究了单独齿向修形,单独齿廓修形与组合修形等不同的修形方式和修形量对接触印痕、齿根应力与传动误差的影响规律。结果表明:与修形前相比,变厚齿轮和圆柱齿轮单独齿向鼓形修形使得齿面接触区域减小,齿面接触应力与齿根弯曲应力增大,传动误差峰峰值增加;圆柱齿轮齿向边坡修形可以使得接触印痕从小端移动至轮齿中部,解决偏载现象;齿廓鼓形修形使得接触印痕呈现增大趋势,可以消除边缘接触现象;接触印痕对齿廓边坡修形最为敏感;变厚齿轮齿廓鼓形修形和圆柱齿轮齿向边坡修形的组合修形方式明显增加接触印痕面积,降低接触应力和传动误差。     

内啮合短齿高直齿轮承载传动误差研究

齿轮承载传动误差是评价齿轮动态啮合性能的一个重要指标,承载传动误差波动幅值越小,齿轮副动态啮合性能越好。针对目前直齿内啮合齿轮承载传动误差研究不充分的问题,以Romax软件为工具,建立内啮合短齿高直齿轮副模型,研究了内啮合短齿高直齿轮齿廓修形参数和螺旋线修形参数对承载传动误差波动幅值的影响,获得了修形参数对承载传动误差波动幅值的影响规律,并采用粒子群算法研究了内啮合短齿高直齿轮修形优化设计方法。研究成果为提高内啮合短齿高直齿轮的动态啮合性能提供了依据。     

不同重合度非圆齿轮设计及弯曲应力分析

非圆齿轮传动具有广泛的应用场景。针对非圆齿轮传动,采用齿轮啮合原理和材料力学等原理及方法,提出了大重合度非圆齿轮设计方法。探讨了非圆齿轮传动原理和节曲线构建方法,计算了其节曲线曲率半径和重合度方程。建立了不同重合度非圆齿轮轮齿时变啮合刚度与载荷分配率计算模型,推导了不同重合度非圆齿轮齿根弯曲应力方程。探讨了不同结构参数下非圆齿轮副重合度、时变啮合刚度、时变载荷分配率及齿根弯曲应力变化规律,确定了轮齿所受最大载荷位置。开展了不同重合度非圆齿轮齿根弯曲应力仿真分析和实验测量,与理论计算结果进行了对比分析,最大误差分别约为4.8%和5.9%,验证了理论方法的合理性与正确性,为大重合度非圆齿轮传动的工程应用奠定了基础。     

Dynamic analysis of involute spur gears with asymmetric teeth

New gear designs are needed because of the increasing performance requirements, such as high load capacity, high endurance, low cost, long life, and high speed. In some applications, such as in wind turbines, the gears experience only uni-directional loading. In these instances, the geometry of the drive side does not have to be symmetric to the coast side. This allows for the designing of gears with asymmetric teeth. In previous studies related to bending stress and load capacity, high performance has been achieved for gears with asymmetric teeth. These gears provide flexibility to designers due to their non-standard design. If they are correctly designed, they can make important contributions to the improvement of designs in aerospace industry, automobile industry, and wind turbine industry. At high operation speeds, there is always a concern of dynamic loads and vibrations of equipment. Therefore, there is a need to fully understand the dynamic behavior of gears with asymmetric teeth. Thus, the primary objective of this paper is to use dynamic analysis to compare conventional spur gears with symmetric teeth and spur gears with asymmetric teeth. The secondary objective is to optimize the asymmetric tooth design in order to minimize dynamic loads. This study offers preliminary results to designers for understanding dynamic behavior of spur gears with asymmetric teeth. For this study, a dynamic model was developed, using MATLAB, and used for the prediction of the instantaneous dynamic loads of spur gears with symmetric and asymmetric teeth. Furthermore, a 2-D three-tooth model was developed for finite element analysis. Fast Fourier transform was used for the frequency analysis of the static transmission errors. It is shown that generally, the dynamic factor, for spur gears with asymmetric teeth, increases with increasing pressure angles on the drive side. For asymmetric teeth, increasing the addendum leads to a significant decrease in the dynamic factor. The static transmission error, at the center of the single tooth contact zone, decreases with increasing pressure angle. The first two harmonics slightly increase with increasing pressure angle. It is further shown that the amplitudes of harmonics of the static transmission errors are significantly reduced when asymmetric teeth with long addendum providing high gear contact ratio close to 2.0 are used.     

多齿差摆线齿轮泵设计计算探讨

针对多齿差摆线泵设计中参数计算和选择中存在的问题,认为啮合界限点并不直接影响圆弧齿轮齿根圆半径和摆线轮齿顶圆半径的取值;重合度的计算应以圆弧齿轮和摆线轮的齿顶圆半径作为计算的依据,圆弧齿轮的齿根圆上的齿廓不一定进入啮合;摆线轮齿顶圆半径可以大于交叉点,这时有可能产生齿廓干涉,必须进行检验。以奇异点作为摆线齿顶圆的界限点不能保证齿廓不产生齿廓干涉。     

Integrated wear prediction model for cylindrical gear with variable hyperbolic circular arc tooth trace under mixed elastohydrodynamic lubrication

Cylindrical gear with variable hyperbolic circular arc tooth trace (VH-CATT) is a new type of gear. Sliding wear is the main mode of the surface failure of multiple mechanical parts. Both the lubrication state and contact temperature considerably influence wear characteristics, which may aggravate the transmission performance of gear pairs. Wear, contact temperature, as well as lubrication states are jointly explored. Therefore, an integrated wear prediction model was proposed through taking into account flash contact temperature and surface roughness of VH-CATT cylindrical gears in mixed elastohydrodynamic lubrication. According to the equivalent ellipse contact model of VH-CATT cylindrical gears and tooth surface equation, normal curvature and velocity relations for VH-CATT cylindrical gears were observed, and the normal meshing force was obtained through the consideration of load sharing coefficients and quality grades. Flash contact temperature was estimated by using the literature. This study proposes analytical solutions for investigating how various surface roughness, operation, and geometric parameters affect asperity contact ratio (ACR), asperity contact pressure (ACP), flash contact temperature (FCT), as well as wear depth (WD) related to driving gears. ACR, ACP, FCT, as well as WD initially decrease and then increase from engaging-in to engaging-out processes. The minimum occurs at the pitch point. The WD declines as module, cutter radius, and rotational velocity increase while augmenting when surface roughness and torques increase. The maximum and minimum wear depths in driving gears occur at the dedendum and pitch point, respectively. Its overall wear is reduced by 23.16 % compared to the wear of spur gears. The results are valuable for the studies of tooth pitting, wear resistance, and fatigue life improvement for VH-CATT cylindrical gear. These studies can provide verification data and references required for engineering designs and VH-CATT cylindrical gear operations.

     

高速动车组斜齿轮的齿根裂纹萌生寿命数值计算

为分析高速动车组斜齿轮的齿根裂纹萌生寿命,采用UG建模软件建立了斜齿轮副的三维模型,并通过ABAQUS软件确定了裂纹萌生位置。基于疲劳损伤累积理论,对试验齿轮分别采用名义应力法和局部应力应变法模拟计算出裂纹萌生寿命;进行了高频疲劳试验,得到了裂纹萌生寿命,通过对比模拟结果与试验结果,确定了最佳损伤模型,计算得出了斜齿轮齿根的裂纹萌生寿命。分析了载荷、表面粗糙度、残余应力、齿顶修缘等因素对裂纹萌生寿命的影响规律。研究结果表明,载荷及表面粗糙度对裂纹萌生寿命的影响比较显著;裂纹萌生寿命随着残余压应力的增大而延长;适当的修形可延长斜齿轮裂纹萌生寿命。     

涡轮起动机传动系统的齿轮副三维啮合分析

针对某涡轮起动机传动系统中的故障齿轮副,在对齿面进行精确描述的基础上,建立了三维有限元模型;基于接触非线性分析理论,计算了在一个啮合周期内,对应不同啮合位置时载荷在啮合轮齿间的分配规律,以及啮合刚度随啮合位置的变化关系,为传动系统动载荷计算奠定了基础;计算了啮合周期内齿面的最大接触应力与齿根最大弯曲应力,这不仅为齿轮副的故障分析提供了依据,而且为进一步的寿命预估与可靠性计算提供了应力数据.     

准双曲面齿轮准静态接触分析和试验研究

建立了精确的准双曲面齿轮的轮齿面和过渡曲面数学模型;选择用平均接触椭圆长半轴、接触线方向角和传动误差曲线交点来评价齿面接触斑点和传动误差;以一个准双曲面齿轮副为计算实例,建立了适合准静态齿面接触分析的准双曲面齿轮传动系统有限元分析模型;通过准静态加载齿面接触特性分析,得到齿根弯曲应力、接触应力和传动误差的变化规律,分析载荷的影响情况,并比较了有限元结果与经验公式计算结果。开发了准双曲面齿轮试验台,进行齿面接触斑点和齿根弯曲应力检测,试验结果与仿真结果的一致性较好。     

齿轮弯曲强度与沉切量关系研究

滚—磨工艺加工的齿轮,由于磨前滚刀有凸台,齿轮根部就有沉切。沉切量与磨前滚刀结构参数和变位系数及留磨量等参数有关。在磨前滚刀参数一定的条件下,对不同沉切量的齿轮分别用有限元方法计算了齿根拉应力和压应力,结果表明：沉切量与弯曲强度之间存在最佳的对应关系。     

Performance improvement method for Nylon 6 spur gears

Plastic gears made of Nylon 6 are especially susceptible to failure due to extreme heat accumulation in the single tooth mesh area, which results in damage that consequently shortens gear teeth life and causes transmission errors. In this experimental study, the teeth width of plastic spur gears made of Nylon 6 were modified and investigated. The values of load sharing, F/b, in single and double tooth meshing areas were leveled by widening the single tooth zone along the meshing area, and the performances of both modified and unmodified gears were studied experimentally under three different loadings. It was observed that modified Nylon 6 gears exhibit lower tooth temperatures, which results in a decrease in wear rate as compared to unmodified gears. Consequently, teeth width modification helps to increase Nylon 6 gear performance.