Evaluation of the strength,wear, and durability of a corrected cylindrical involute gearing,with due regard for the tooth engagement conditions

A method for calculating the wear and durability of helical gearings is used to investigate the effect of double–single–double tooth engagement on the maximum contact pressures, tooth wear, and durability of a corrected cylindrical involute gearing under constant tooth contact conditions. A technique is presented for determination of the angles of transition from the doubleto the single-tooth contact and vice versa. Gear tooth profile correction is found to reduce the maximum contact pressures by up to 20%. The teeth of the gear wheel reach their wear allowance faster than those of the pinion do. Depending on the degree of correction, the maximum wear occurs at different characteristic contact points: at the entry to the double-tooth mesh, at the entry to the single-tooth mesh, or at the exit out of the mesh. The durability of the gearing is found to be at its maximum at certain overlap ratios, its magnitude being observed to increase substantially (by up to 50%). The results obtained are presented in graphic form, which enables one to reveal the laws governing the effect of the engagement conditions.     

齿轮齿根应力轮齿挠度啮合刚度和端面载荷系数的研究

抛弃把轮齿形状视为悬臂梁的假设,直接从实际齿形出发,以相似理论为基础,通过边界元采样计算和回归分析,建立了齿根应力、轮齿挠度和啮合刚度计算的新方法。分别提出了弯曲与接触强度端面载荷系数的定义式和新的计算式。提出了实际双齿啮合必要和充分条件及实际重合度的概念及公式。提出了一种新的重合度系数公式。比较分析了ISO6336的一些问题。所给齿根应力计算新方法不需种种假设、理论基础先进、实际准确性好、计算大为简化,可以取代W．Lewis的悬臂梁方法。其余所给公式亦较明确合理。     

润滑和载荷状态对聚甲醛齿轮服役性能的影响

基于齿轮耐久性能试验台开展了一系列干接触/油润滑下POM(聚甲醛)-POM齿轮副承载能力试验,并测量了服役过程中的轮齿温度、磨损量、齿廓精度和齿面形貌。试验发现,POM齿轮失效形式与载荷和润滑方式有关。通过对齿面微观形貌和磨屑表征,确认干接触下POM齿轮主要磨损模式为黏着磨损与磨粒磨损,而油润滑下POM齿轮失效形式为接触疲劳失效。由于润滑油减少了齿面摩擦,降低了运行温度,延缓了齿面劣化程度,因此POM齿轮在油润滑下的承载能力明显提高。     

RV减速器摆线轮磨损量的数值计算与分析

基于Archard磨损模型和Hertz接触理论为理论基础,将摆线轮齿廓啮合区域离散化,建立了摆线轮磨损的计算模型;根据该计算模型分析了各啮合点处滑动系数、磨损率、磨损量与啮合相位角之间的关系,并进行曲线拟合.结果表明,建立的数值计算方法可以实现对不同修形方法、不同尺寸、不同工况条件下摆线针轮齿廓磨损量的定量计算.     

Durability improvement method for plastic spur gears

An experimental investigation of power-transmission plastic spur gears was performed by inspecting both the characteristics of wear and durability, and a durability improvement method is proposed that either drills an internal hole or inserts a steel-pin in the internal hole of the gear tooth, and this proposed method was verified. In the case of acetal gears, the amount of wear was observed to increase with the development of plastic deformation, and an increase in tooth stiffness occurred due to the brittle material property of acetal. On the other hand, in the case of nylon gears, the proposed method was shown to reduce the tooth temperature compared to the original gear, thus reducing the amount of wear and prolonging service life. Hence, the proposed method was proven to be practically applicable to plastic gears made from soft polymers that show visco-elastic properties such as nylon.     

双曲柄双摆线行星传动的力分析与效率计算

双曲柄双摆线行星传动舍二级减速，即渐开线齿轮定轴传动和双摆线齿轮平动式行星传动，中间环节为双．曲柄。探讨了该型传动的作用力分析与效率计算。     

一种新型齿轮综合偏差测量齿轮及测量原理

传统渐开线齿轮综合偏差的检测常采用齿轮单面啮合法和齿轮双面啮合法。由于2种方法的测量原理及测量参数等不同,需采用齿轮单啮仪和齿轮双啮仪2种仪器分别进行测量,从而分别获得被测齿轮的切向综合偏差和径向综合偏差,2种偏差无法通过一次啮合检测得到。针对传统齿轮综合检测的不足,设计了一种由2个特殊半齿测量齿轮组成的新型测量齿轮,提出了一种新的齿轮综合偏差测量原理,并给出了其综合偏差结果的评定方法。该测量齿轮与被测齿轮通过一次类单面啮合测量,获得产品齿轮两侧齿面的切向综合偏差和径向综合偏差,明显提高了渐开线齿轮综合偏差的检测效率,降低了在测量设备上的投资。     

Wear simulation of spur gears

This paper deals with prediction of wear in spur gears, which has been calculated using an approach in which the wear depth on a tooth surface is integrated over time using the Euler integration method. Variations in pressure distribution over the surface have been considered, as well as changes in curvature and surface profile of the teeth as they wear. The paper focuses on the use of an appropriate wear model for simulating wear using calculated conditions between high-performance slow-running lubricated spur gears. A numerical model for prediction of surface interaction of spur gears developed earlier by the authors has been applied as the basis for the simulation of wear using different wear models. Owing to the nature of the wear models, methods of calculating the contact temperature have been investigated for the specific case of interacting gear teeth. It was found that a linear wear model, when compared with a more complex oxidation model and with a model based on adsorption of lubricant molecules, satisfactorily predicts wear. It was also found that it is the geometry of the gears that causes sliding velocity to be the dominant wear-inducing factor, and so determines the general nature of the wear behaviour.     

矿用减速器斜齿轮副动态啮合仿真分析

利用大型有限元分析软件ANSYS建立了某矿用减速器变位斜齿轮副多齿对啮合的有限元非缌性接触分析模型.基于该模型,对齿轮副进行了在一定工况下的动态啮合仿真分析,得出瞬态啮合时轮齿的接触状态、接触应力、齿根弯曲应力以及主从动齿轮的转矩、转速随啮合位置变化的规律符合实际啮合规律,同时得到最恶接触位置,并在此位置进行了静态接触强度分析.分析结果表明,动态啮合仿真能够真实反映轮齿的接触状态、接触应力以及齿根弯曲应力的动态变化,静态接触分析进一步验证动态啮合分析的可靠性,也为疲劳寿命分析提供了依据.     

齿轮故障信号多重分形维数的形态学计算方法

针对传统的多重分形维数计算方法的缺陷,提出基于数学形态学操作的多重分形维数计算方法,并证明了与盒计数法计算多重分形维数的一致性.对实际的齿轮正常、齿面磨损故障和断齿故障信号进行了分析,结果表明,与盒计数法相比,基于数学形态学计算的多重分形维数能够准确区分齿轮的工作状态,并且数学形态学只涉及简单的加减和取大、取小运算,计算更加简单、快速.     

An Experimental Investigation of the Influence of the Lubricant Viscosity and Additives on Gear Wear

The influence of lubricant viscosity and additives on the average wear rate of spur gear pairs was investigated experimentally. The gear specimens of a comprehensive gear durability test program that made use of seven lubricants covering a range of viscosities were examined to measure gear tooth wear. The measured wear was related to the as-manufactured surface roughness, the elastohydrodynamic film thickness, and the experimentally determined contact fatigue lives of the same specimens. In general, the wear rate was found to be inversely proportional to the viscosity of the lubricant and to the lambda ratio (also sometimes called the specific film thickness). The data also show an exponential trend between the average wear rates and the surface fatigue lives. Lubricants with similar viscosities but differing additives and compositions had somewhat differing gear surface fatigue lives and wear rates.     

硬齿面双圆弧齿轮滚刀的齿面方程及二次刀具廓形设计

论述了硬齿面双圆弧齿轮滚刀的结构特点，从双圆弧齿轮滚刀的基本蜗杆齿轮面方程出发，利用啮合原理推导出具有直沟负前角的滚刀的前刀面齿形计算公式和铲齿齿背的曲面方程，再利用齿背曲面和铲磨运动的关系求出铲磨滚刀的砂轮轴向载面廓形，并给出了负前角双圆弧滚刀铲磨砂轮截面的具体算例。     

齿轮参数化精确建模及其有限元分析

在CATIA中使用fog、f(x)函数设计功能，根据机械零件中有关齿轮的设计原理对标准渐开线直齿圆柱齿轮精确建模。在此基础上对齿轮模型在ANSYS中进行单齿面和双齿面2种工况的接触啮合有限元分析。充分显示了集CAD／CAE为一体的工程设计思想。     

Study on development of polyamide gears for improvement of load-carrying capacity

In polyamide based gears, thermal damage of the gear tooth surfaces occurs during gear meshing due to accumulated heat in the tooth body. In the experimental study reported in this paper, polyamide gear teeth have been modified in order to distribute the generated heat on the tooth surface by means of drilled cooling holes at different locations on the gear tooth body. The main aims of this paper were to study the effect of cooling holes on the accumulated heat on the tooth surface and on the measured wear. It was shown that the drilled cooling holes on the tooth body decreased the tooth surface temperature and led to an increase in the load carry capacity and improved wear resistance. Geometrically modified gears have showed an improved service life and a decreased surface temperature.     

Experimental studies on the effects of reduction in gear tooth stiffness and lubricant film thickness in a spur geared system

Gears are one of the most common mechanisms for transmitting power and motion and their usage can be found in numerous applications. Studies on gear teeth contacts have been considered as one of the most complicated applications in tribology. Depending on the application, the speed and load conditions of teeth may change triggering several types of failures on teeth surface such as wear, scuffing, micro-pitting and pitting. The above-mentioned faults influence changes in vibration and acoustic signals, due to changes in operating conditions such as increase in temperature and decrease in lubricant film thickness and specific film thickness. These abnormal changes result in cumulative effects on localised or distributed faults on load bearing surfaces of gears. Such damages cause reduction in tooth stiffness and severity of damage can be assessed by evaluating the same using vibration-based signals.This paper presents the results of experimental investigations carried out to assess wear in spur gears of back-to-back gearbox under accelerated test conditions. The studies considered the estimation of operating conditions such as film thickness and their effects on the fault growth on teeth surface. Modal testing experiments have been carried out on the same gear starting from healthy to worn out conditions to quantify wear damage. The results provide a good understanding of dependent roles of gearbox operating conditions and vibration parameters as measures for effective assessment of wear in spur gears.     

Failure analysis and wear mechanism study of a heavily loaded gear

Failure analysis and a study of the wear mechanism were performed on a heavily loaded carburized gear with some unusual features. The analysis showed that the different failure forms on the tooth surface of the gear were dependent on the sub-surface shearing stress, the lubrication conditions and the surface roughness. Delaminations formed on the addendum surface were the main reason for the gear failure. A suggestion for improvement has been tried, and a desirable result has been obtained.     

The influence of misalignments on mesh performances of hypoid gears

A new method for tooth contact analysis in mismatched hypoid gears is applied for the investigation of the influence of misalignments of the mating members on mesh performances. By using the corresponding computer program, the influence of running offset error, pinion’s axial adjustment error, and angular position errors of the pinion axis on the shape and position of path of contact and of potential contact lines under load, on separations along these contact lines, on angular displacements of the gear member, and on the variation of the angular velocity ratio through a mesh cycle, have been determined. The results obtained have shown that the position errors of the mating members cause edge contact on the tip of the pinion or gear tooth, worsen the conjugation of the contacting tooth surfaces, and considerably increase the angular displacements of the gear member and the angular velocity ratio variation through the whole mesh cycle, that considerably worsens the mesh performances.     

渗碳硬齿面双圆弧齿轮超硬加工技术

为了拓展圆弧齿轮的应用范围 ,本文介绍了渗碳硬化双圆弧齿轮超硬加工技术。应用这项技术加工的硬齿面双圆弧齿轮 ,其承载能力与相同规格的硬齿面渐开线齿轮相当     

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...     

Performance evaluation of multilayer thin film coatings under mixed rolling–sliding dry contact conditions

This paper focuses on the application of advanced finite element analysis to simulate the response of complex multilayer coatings when subjected to mixed rolling–sliding dry contact conditions, typical of those experienced by heavily loaded gear tooth flanks. In this study, a versatile model is developed to investigate the response of a variety of complex coatings. Through the investigation of three advanced surface coatings the developed model is shown to offer detailed subsurface stress and strain information, quantifying the benefits provided by the application of each coating.A number of rolling contact fatigue tests were also conducted to complement the computational simulations. An adapted twin disc testing machine was used to investigate the progressive wear rates of the three advanced surface coatings when subjected to mixed rolling–sliding contact at high load and in dry conditions. The result is a clear indication that advanced surface coating techniques can provide significant improvements in wear resistance and surface durability. From the rolling contact fatigue experiments conducted in this study, a multilayer tungsten carbide/carbon coating was shown to provide the most significant increase in surface durability with a 16-fold reduction in measured weight loss compared to the uncoated substrate over the 145,000 cycle test duration investigated.