Tooth Profile Modification Research Articles

Analysis of Spur Gear with Tooth Circular Discontinuity for Weight Reduction

The design of gears and gear drives are becoming challenging in automobile applications in which low contact ratio gears are required to transmit higher loads and be lighter in weight. There are various methods available for optimizing the design. Some researches have been taken place in the areas of gear tooth profile modifications for providing internal stress relief and weight reduction. In most cases, the maximum loads are assumed to be acting on the tip of the tooth. In this study, investigations are carried out on the effect of circular discontinuity on the weight reduction without affecting the root stress. The maximum tangential load is applied on the highest point of single tooth contact. The results show that with the modified gear tooth having a combination of two circular discontinuities of size 0.4 times the module not only provides weight reduction but also gives stress relief at the root.

Effect of tooth profile modification on wear in internal gears

Internal gears are often used in the automotive industry when two gears are required to rotate in the same direction. Tooth shapes, slippage speeds at the beginning and end of meshing are different according to the external gears. Manufacturing of internal gears is more difficult than external gears. Thus, it is necessary to determine the working conditions and wear behavior of internal gears carefully. The profile modification method in terms of strength and surface tension of the gear mechanism are performed in order to increase the load-carrying capability. In this study, profile modification method was performed in the internal gears to reduce the wear on the teeth. For this purpose, the wear of the internal gears was theoretically investigated by adapting the Archard wear equation to the internal gears. Closed circuit power circulation system was designed and manufactured to experimentally investigate the wear in internal gears. With this system, wear tests of gears made of St 50 material without profile modification and different profile modifications were made and the results were compared. Experimental study was performed in the same loading and cycle time conditions to validate the theoretical results and it was seen that the results are compatible. According to the experimental results, it is seen that in the internal gears, when profile modification done the wear is decreased in the teeth tip region.

Contact Strength Analysis of a Cycloidal Gear Reducer with Tooth Profile Modification

Contact Strength Analysis of a Cycloidal Gear Reducer with Tooth Profile Modification

Mesh stiffness modeling considering actual tooth profile geometry for a spur gear pair

Some tooth profile geometric features, such as root fillet area, flank modification and wear are of nonnegligible importance for gear mesh stiffness. However, due to complexity of analytical description, their influence on mesh stiffness was always ignored by existing research works. The present work derives analytical formulations for time-varying gear mesh stiffness by using parametric equations of flank profile. Tooth geometry formulas based upon a rack-type tool are derived following Litvin's vector approach. The root fillet area and tooth profile deviations can therefore be fully considered for spur gear tooth stiffness evaluation. The influence of gear fillet determined by tip fillet radius of the rack-type tool is quantified parametrically. The proposed model is validated to be effective by comparing with a finite element model. Further, the model is applied to investigate the stiffness variations produced by tooth addendum modification, tooth profile nonuniform wear and modification.

Microgeometrical tooth profile modification influencing efficiency of planetary hub gears

Microgeometrical tooth profile modification influencing efficiency of planetary hub gears

Microgeometrical tooth profile modification influencing efficiency of planetary hub gears

Planetary hub systems offer desired speed and torque variation with a lighter, compact and coaxial construction than the traditional gear trains. Generated friction between the mating teeth flanks of vehicular planetary hubs under varying load-speed conditions is one of the main sources of power loss. Modification of gear tooth geometry as well as controlling the contacting surface topography is the remedial action. The paper studies the effect of tooth crowning and tip relief upon system efficiency. It includes an analytical elastohydrodynamic analysis of elliptical point contact of crowned spur gear teeth. The analysis also includes the effect of direct contact of asperities on the opposing meshing surfaces. Tooth contact analysis (TCA) is used to obtain the contact footprint shape as well as contact kinematics and load distribution. A parametric study is carried out to observe the effect of gear teeth crowning and tip relief with different levels of surface finish upon the planetary hubs' power loss.

Geometry Modification of Helical Gear for Reduction of Static Transmission Error

Gear systems are extensively employed in mechanical systems since they allow the transfer of power with a variety of gear ratios. So gears cause the inherent deflections and deformations due to the high pressure which occurs between the meshing teeth when transmit power and results in the transmission error. It is usually assumed that the transmission error and variation of the gear mesh stiffness are the dominant excitation mechanisms. Predicting the static transmission error is a necessary condition to reduce noise radiated from the gear systems. This paper aims to investigate the effect of tooth profile modifications on the transmission error of helical gear. The contact stress analysis was implemented for different roll positions to find out the most critical roll angle in view point of root flank stress. The PPTE (peak-to-peak of transmission error) is estimated at the roll angles by different loading conditions with two dimensional FEM. The optimal profile modification from the root to the tip is proposed.

Sliding ratio for novel cycloidal gear drive

In this paper, for a novel spur cycloidal gear drive with a modified tooth profile, the equations of the sliding ratio are deduced from those of its tooth profile. Using the sliding ratio equations, the sliding ratio of the novel cycloidal gear drive is investigated and effects of the drive parameters on the sliding ratio are analysed. The sliding ratio of the novel cycloidal gear drive is then compared with that of an involute gear drive. The results show that the sliding ratio of the novel cycloidal gear drive is small and distributed evenly along its rotating angles, which makes the drive operate smoothly and have a long wear life.

Spur gears with longitudinal tooth profile modification mesh creating which is suitable for stress analysis

Spur gears with longitudinal tooth profile modification mesh creating which is suitable for stress analysis

Effects of random tooth profile errors on the dynamic behaviors of planetary gears

In this paper, a nonlinear random model is built to describe the dynamics of planetary gear trains (PGTs), in which the time-varying mesh stiffness, tooth profile modification (TPM), tooth contact loss, and random tooth profile error are considered. A stochastic method based on the method of multiple scales (MMS) is extended to analyze the statistical property of the dynamic performance of PGTs. By the proposed multiple-scales based stochastic method, the distributions of the dynamic transmission errors (DTEs) are investigated, and the lower and upper bounds are determined based on the 3σ principle. Monte Carlo method is employed to verify the proposed method. Results indicate that the proposed method can be used to determine the distribution of the DTE of PGTs high efficiently and allow a link between the manufacturing precision and the dynamical response. In addition, the effects of tooth profile modification on the distributions of vibration amplitudes and the probability of tooth contact loss with different manufacturing tooth profile errors are studied. The results show that the manufacturing precision affects the distribution of dynamic transmission errors dramatically and appropriate TPMs are helpful to decrease the nominal value and the deviation of the vibration amplitudes.

Research of thermal deformation of a kinematic wave reducerwith a modified tooth profile during the work in low temperature conditions

In the conditions of the Extreme North working resource of mechanicaltools and machineelements is reduced because of bad weather conditions in this region. At a low temperature materials are exposed to deformation which is capable to break operability of the mechanism. In connection with the high requirements to the accuracy of a kinematic wave reducer, it is necessary to conduct a research for the purpose of comparison of value of thermal deformation and the appointed admission on a reducer detail. If value of thermal deformation is more admission, then it can lead to jamming of the mechanism. The research was conducted for a collected reducer and separately for not loaded driver gear.

Analysis of a Cycloid Speed Reducer Considering Tooth Profile Modification and Clearance-Fit Output Mechanism

The load distribution analysis plays a significant role in the performance evaluation of cycloid speed reducer. However, current analytical models usually ignore elastic deformation, clearances, or assembly errors. These factors must be considered for realistic performance evaluation of cycloid speed reducer. This paper proposes an analytical model for cycloid speed reducer based on unloaded tooth contact and load distribution analyses. The proposed model can predict the loads on various components of the speed reducer in the presence of clearances and eccentricity errors. The results are compared with those predicted by the cycloid speed reducer model based on theoretical geometry. The effect of radial and pin-hole clearances as well as eccentricity errors, on some key design factors, such as contact stress, transmission error, gear ratio, and load on bearing, is investigated. This study can be used to assist the optimal design of cycloid speed reducers.

Gear Clutch with Modified Tooth Profiles

The article presents the results of research of modification design for tooth clutch with low sensitivity to elastic deformation of shafts and assembly errors. The implementation of these conditions by the use of circular tooth profiles is carried out. Based on the given boundary conditions by the limit values of radii of curvature in the longitudinal direction (barrel modification) and the teeth height (profile modification) are defined. According to the results of comparative calculations, recommendations on the selection the parameters of the longitudinal and profile modifications teeth are given. Using the proposed development will enhance the ability of compensating tooth clutch in comparison with a standard analogue.

Research of the load distribution in the wave kinematic reducer with a modified tooth profile and dependence of the load abilities in proportion to its gear ratio and overall dimensions

Nowadays, there are many types of reducers based on work of gear trains, which transfer torque. The most popular reducers are with such type of gearing as an involute gear, a worm drive and an eccentrically cycloid gear. A new type of the reducer will be represented in this work. It is a wave reducer with the modified profile of the tooth close to the profile of the tooth of Novikov gearing. So such reducers can be widely used in drives of difficult technical mechanisms, for example, in mechatronics, robotics and in drives of exact positioning. In addition, the distribution of loading in gearing of teeth of a reducer was analyzed in this paper. It proves that the modified profile of the tooth allows distributing loading to several teeth in gearing. As a result, an admissible loading ability of a reducer becomes higher. The aim of the research is to define a possibility to reduce overall dimensions of a reducer without changing the gear ratio or to increase the gear ratio without changing overall dimensions. So, the result of this work will be used in further research.

Зубчатая муфта с модифицированными профилями зубьев

Зубчатая муфта с модифицированными профилями зубьев

Tooth Profile Modification and Simulation Analysis of Involute Spur Gear

Tooth Profile Modification and Simulation Analysis of Involute Spur Gear

Influence factors on bulk temperature field of gear

The convective heat transfer coefficient of different tooth surfaces and the friction heat flux were identified based on the theory of tribology, heat transfer, and gear meshing theory. A more accurate parametric model of finite element thermal analysis of a single tooth was established by using APDL and the more accurate bulk temperature field of the gear was obtained. The factors that affect the bulk temperature field of gears were also analyzed, and the influence mechanism of each factor was carried out. The results show that high-pressure angle and tooth profile modification cannot only effectively reduce the bulk temperature of the gear, but also benefits the distribution of the bulk temperature. Long-addendum gear is beneficial to the distribution of the bulk temperature. The bulk temperature is proportional to the initial temperature of the lubricating oil. The variations of the equivalent curvature radius, the stiffness and the load sharing ratio of the meshing point are the ultimate cause of the change of the bulk temperature. The results of this paper can provide a more accurate and practical method for obtaining the bulk temperature of the gear, and it also can provide a theoretical basis and method to improve the thermal behavior of gears.

Finite Element Analysis and Tooth Profile Modification Study on Traction Gear of High Speed and Heavy Load Locomotive

Finite Element Analysis and Tooth Profile Modification Study on Traction Gear of High Speed and Heavy Load Locomotive

Influence comparisons of two version tooth profile modifications on face gear dynamic behaviors

Face gear drives in first-stage gear drives of helicopter main gearboxes occupy several strong points versus traditional spiral bevel gear drives, and are addressed by many scholars. However, face gear vibration suppressions, such as calculation solutions of face gear dynamics associated with tooth profile modifications and influences of tooth profile modifications on face gear dynamic behaviors, are not to be investigated, according to the limited published issues. Thus, in the study, influence mechanisms of two version tooth profile modifications, namely, linear addendum modifications of face gears and arcuate dedendum modifications of pinions, on face gear dynamic base parameters, such as mesh stiffness and static transmission errors, are discussed, and calculation solutions of two version tooth profile modifications are constructed. Meanwhile, an equivalent evaluation solution between linear addendum modifications of face gears and arcuate dedendum modifications of pinions is proposed, and a four degree-of-freedom dynamic model of face gear drives is established. Furthermore, dynamic behaviors of an example case of face gear drives associated with two version tooth profile modifications are simulated. The results indicate dynamic behavior crises of face gear drives would not to be caused by two version tooth profile modifications, and when two version tooth profile modifications are equivalent, the effect of linear addendum modifications of face gears on dynamic mesh force suppressions at whole frequencies is better than that caused by arcuate dedendum modifications of pinions, while, as for mesh frequency, the dynamic mesh force suppression effect caused by arcuate dedendum modifications of pinions is better, and considered dynamic mesh force suppression average values associated with two version tooth profile modifications, arcuate dedendum modifications of pinions are recommended. These contributions would improve modification developments and engineering applications of face gear drives in the future.

An efficient honing method for face gear with tooth profile modification

To improve the production efficiency of the face gear, this paper studies a honing method for face gear with tooth profile modification and proposes a face gear honing principle. Based on the honing principle, a mathematical model of the face gear honing cutter is derived. The tooth profile of the honing cutter is modified by controlling the longitudinal modification coefficient of the generating rack cutter. Then, the tooth flank equation of the honed face gear is derived according to the machine structure. To ensure the face gear accuracy, an error analysis model including the axial, tangential, and radial tool setting errors is presented, and the effects of tool setting errors on the face gear geometry errors are analyzed. The honing cutter is manufactured, and the face gear honing experiments are performed. The measurement results of the tooth surface deviations indicate that the maximum deviation decreases from 39.4 to 15.1 μm by amending the processing parameters. The experimental results prove that the honing method is an effective approach to improve the production efficiency of the face gear.