共查询到20条相似文献,搜索用时 15 毫秒
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Shyue-Cheng Yang 《The International Journal of Advanced Manufacturing Technology》2005,26(5-6):448-456
This paper describes a simple approach based on the gear theory for deriving a helical gear with asymmetric involute teeth. A helical gear with asymmetric involute teeth can be easily obtained through the envelope theory for the one-parameter family of surfaces. The mathematical models for asymmetric helical gears can be provided by the application of two imaginary rack cutters. The investigation on the undercutting analysis of the asymmetric helical gear is studied based on the developed mathematical model and the method of tooth-profile shifting. Here we provide geometric modeling of the designed asymmetric helical gear meshing when assembly errors are present. Stress analysis for the helical and the cylindrical forms are constructed. To illustrate the effectiveness of the approach, an analytical expression of helical gear with asymmetric involute teeth is given. 相似文献
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Dynamic analysis of involute spur gears with asymmetric teeth 总被引:1,自引:0,他引:1
Fatih Karpat Stephen Ekwaro-Osire Kadir Cavdar Fatih C. Babalik 《International Journal of Mechanical Sciences》2008,(12):1598-1610
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. 相似文献
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针对等分模型下配对齿工作齿廓出现实际啮合不会发生的齿廓交叉或者分离现象,根据渐开线齿廓啮合几何关系,提出一种不存在假设误差的偏心渐开线齿轮传动不等分模型,以奇数齿偏心齿轮传动为例,给出不等分模型数值求解的完整算法。根据内公切线与两轮配对齿工作齿廓的交点数不同,啮合点搜索算法能处理任意转角关系下连续转动的4种情形,能正确产生7种不同的配对结果。计算结果表明,几何中心连线与内公切线段的交点不相互等分两线段,啮合点不总是在内公切线上,和轴心距大小无关。当基准齿工作齿廓坐标点数为5 000点时,啮合点搜索的坐标控制精度可达到0.001 mm,转角误差精度可达到0.001°,计算方法可以得到非常精确的转角关系,可以为偏心齿轮传动的准确分析和优化设计提供依据。 相似文献
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TI 环面蜗杆砂轮磨齿原理 总被引:6,自引:1,他引:6
根据空间交错轴齿轮啮合理论,对TI环面蜗杆砂轮磨齿原理进行了理论研究,推导出了基本方程,分析了磨削渐开线直、斜齿圆柱齿轮时的接触线分布规律,并得到了齿面上不存在啮合界限线的判定条件,经微机模拟接触过程,表明此方法是一种高效的齿面磨削方法。 相似文献
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This paper describes a simple approach based on the gear theory for deriving a helical gear with asymmetric involute teeth. A helical gear with asymmetric involute teeth can be easily obtained through the envelope theory for the one-parameter family of surfaces. The mathematical models for asymmetric helical gears can be provided by the application of two imaginary rack cutters. The investigation on the undercutting analysis of the asymmetric helical gear is studied based on the developed mathematical model and the method of tooth-profile shifting. Here we provide geometric modeling of the designed asymmetric helical gear meshing when assembly errors are present. Stress analysis for the helical and the cylindrical forms are constructed. To illustrate the effectiveness of the approach, an analytical expression of helical gear with asymmetric involute teeth is given. 相似文献
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根据渐开线齿轮啮合原理,推导了基于某一坐标系统的非对称渐开线齿轮齿廓曲线方程。利用Autodesk Inventor软件的VBA二次开发技术,对非对称齿轮的三维实体模型进行了构建。通过对非对称齿轮动力学模型等价变换,利用ADAMS虚拟样机技术,对非对称齿轮动态啮合传动过程进行了仿真,并与对称齿轮仿真结果进行了对比研究。 相似文献
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针对各种齿轮传动提出端面重合度的统一定义,并且推导其计算表达式,进一步讨论了渐开线齿轮副、微线段齿轮副和正弦齿廓齿轮副的端面重合度的计算问题。齿轮副的端面重合度定义为齿轮作用角(即一对轮齿从进入啮合到脱离啮合过程中齿轮所转过的角度)与齿轮的齿距转角的比值。根据齿轮啮合原理,由基本齿条的轮廓曲线能够获得其啮合线方程。根据所获得的啮合线方程,以及给定的齿轮副齿顶线方程,就能够根据本文的计算式得到齿轮副的重舍度。对于渐开线齿轮副,该定义与众所周知的“啮合线长度与基节之比”的结果相同。该定义同样适用于非渐开线齿轮副,例如微线段齿轮副、正弦齿廓齿轮副等,而且计算结果更可靠。 相似文献
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含侧隙齿轮副的动载荷分析 总被引:1,自引:0,他引:1
以振动理论为基础,提出一种考虑齿轮拍击振动的齿轮动载荷的数值计算方法。建立计算动载荷的齿轮冲击模型,在模型中考虑了齿轮正、反冲击时实际的啮合刚度,并给出啮合柔度的计算方法。分析在考虑静态传递误差、啮合刚度、侧隙、摩擦力及外部扭矩变化等多种激励时,作用在轮齿上的动态载荷以及整个齿轮上的综合动态载荷的计算公式。最后通过实例分析作用在轮齿上的动态载荷、综合动态载荷变化规律以及相关激励参数对动态载荷的影响。 相似文献
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Tan WeimingDepartment of Mechanical Engineering Foshan University Foshan China 《机械工程学报(英文版)》2004,17(4):595-597
Common definition and calculating expressions of end-surface contact ratio for all type of gears are put forward, and with calculation expressions for involute gears, micro-segments profile gears, and sine-curved profile gears being discussed. The end-surface contact ratio of gears is defined as the ratio of the action angle (the rotation angle of gear from gear-in to gear-out for one pair of teeth) to the rotation angle per pitch (or central angle per tooth). According to the theory of gearing, equation of the meshing line can be deduced from the tooth profiles of basic rack. Having obtained the equation of the meshing line, and being given the addendum outline of the gears, the contact ratio can be calculated with the calculation expressions. For the involute gears, this definition has same effect as the well-known definition: ratio of the contact line to the base pitch. This definition of contact ratio is also suitable to other non-involute gears, such as micro-segments profile gears, sine-curved prof 相似文献
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The authors have proposed methods (lead crowning and profile modification) for modifying the geometry of spur gears and investigated the contact pattern as well as the transmission errors to recommend the appropriate amount of modification. Based on the investigation, dynamic load of the modified spur gear drive has been calculated, which is helpful to predict the life of the designed gear drive. Computer programs for simulation of meshing, contact and dynamics of the modified spur gears have been developed. The developed theory is illustrated with numerical examples. 相似文献
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In a given size of symmetric involute gear designed through conventional approach, as the load carrying capacity is restricted at the higher pressure angle due to tipping formation, the use of the asymmetric toothed gear to improve the fillet capacity in bending is examined in this study. Non-standard asymmetric rack cutters with required pressure angles and module are developed to generate the required pinion and gear of a drive with asymmetric involute surfaces and trochoidal fillet profiles. The respective profiles thus generated are optimized for balanced fillet stresses that are equal and possibly the lowest also. For this study of optimization, several non-standard asymmetric rack cutters are designed to accommodate different combinations in the values of pressure angle, top land thickness ratio, profile shift, speed ratio and the asymmetric factors. However for any drive with a given center distance and a speed ratio, only two non-standard asymmetric rack cutters, one for the pinion and other for the gear are used to generate a required numbers of pinion and gear with different cutter shift values for the purpose of optimization. The influence of these parameters on the maximum fillet stress has been analyzed to suggest the optimum values of these parameters that improve the fillet capacity in bending. The optimization of the asymmetric spur gear drive is carried out using an iterative procedure on the calculated maximum fillet stresses through FEM for different rack cutter shifts and finally the optimum values of rack cutter shifts are suggested for the given center distance and the speed ratio of an asymmetric gear drive. Comparisons have also been made successfully with the results of the AGMA and the ISO codes for symmetric gears to justify the results of the finite element method pertaining to this study. 相似文献
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This paper describes a curved‐face‐width spur gear, specially designed for manufacture from non‐metallic materials. The benefits of this gear are the higher contact ratio, bending and Hertzian contact resistance, and greater tooth stiffness compared to standard spur gears. A modified geometry is proposed for the gear tooth, the height of which varies along the gear face width. Due to the reduction in tooth height, in sections away from the gear centre, lower sliding friction is expected, with consequences for the gear's thermal behaviour. The complex gear geometry makes the design of a die difficult; therefore the gears were cut on a milling machine, using a special kinematic generation process and related equipment. The tooth flank profile, an involute or near involute in sections away from the gear half‐width plane, as well as the flank surface quality determined by the single‐cutter tool used for gear manufacture, influence the meshing condition, and can be detrimental to the thermal behaviour of the gear. Experimental tests were carried out to examine the influence of load and speed on the temperature of the curved‐face‐width spur gears with modified geometry. The measured temperature of the non‐standard gear is further compared with the predicted temperature of plastic standard spur gears of the same specification. 相似文献
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