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This paper presents significant advancements in the design and manufacture of gear systems, particularly focusing on adaptive gear variators. It discusses methodologies for force analysis, dynamic behavior, and design principles of gear variators, supported by experimental research. The exploration includes a comprehensive summary of theoretical developments in gearing and concludes with reflections on future directions in gear design, encapsulating key historical contributions to the field.
Mechanism and Machine Theory, 2005
In this paper the theory of gearing is presented by means of a new approach that does not need reference systems. All equations are written in terms of vectors and therefore are valid regardless of the reference system actually employed. The overall formulation becomes more compact and clearer. As an example, the proposed approach is applied to the generation of spiral bevel gears. To actually perform all calculations, only one reference system is required, thus avoiding the chain of reference systems typical of the traditional approach.
American Journal of Engineering and Applied Sciences, 2017
The gears are today the most widespread and most frequently used mechanical transmissions, all over the world. They must be the factory on an industrial scale, everywhere and have a variety of uses, being extremely important for both the heavy machines of industrial buildings, as well as for domestic appliances, electronics, etc. meet the excessive size normal, big or even huge (used from ships, heavy machines or in energy), but also for the tools watches, or for devices of sizes micro. The work of front wishes to make an overview of the tools and then an introduction to the study of their general and a study customized for gears with fixed. The methods listed for the gears with fixed, can then be customized and used and the gears Planetary Drive (with axis elements). The work of the front and the original components, very much, such as: Geometry, forces, velocities, powers, outputs (gears), which form part of the actual dynamics of the mechanisms and also the most important criterion in respect of the performance of a mechanism.
Acta Mechatronica, 2020
The gearing with changing transmission gear ratio are used as synchronization component and for specific parameters. The gearing with changing transmission gear ratio is used in the practice, even though the "standard" gearing with constant transmission gear ratio are used more often. This article describes how to optimize the design of pitch curves of non-circular gear for given parameters. The non-circular gearing is consisting of two identical gear wheels. For a nonstandard gearing was applied eccentric elliptical gear drive with continuously changing transmission gear ratio. The kinematic properties of this gearing are different from the properties of standard circular gears-spur gear. Thus, the gear ratio changes over the time of one revolution. The article is devoted to problems determining of the stress in a dangerous section of tooth foot using FEM.
Gear Geometry and Applied Theory, 2019
Gear Geometry and Applied Theory
American Journal of Engineering and Applied Sciences
The paper presents an original method for the determination of the yield of the gearbox, gears forces, gearbox and power. It analyzes the influence of certain parameters which affects the efficiency of the gearbox. Also an original method for the determination of the yield of the drive shafts oriented on the basis of the ratio of contact is presented the brief. The relations submitted, can be dynamic synthesis of the drive shafts oriented, in order to enhance the effectiveness of the mechanisms of mesh.
MATEC Web of Conferences
Search for an improved gear tooth flank shape arose from heavy industry problems rolling mills. Original involute gears suffered severe flank damages. So, better gear teeth flanks should improve contact circumstances, decrease the flank pressure, and enhance a lubrication film. This was achieved by a curved, pole symmetric path of contact by purely graphical methods. And the developed gears, proven in heavy industry applications, showed highly improved properties. Specimens of both gear geometries, which were made of tempered and nitrided alloy steel, were tested on an FZG testing machine, and results confirmed the theoretical foundations of S-gears. Then it was necessary to replace the graphical method by a numerical one and to define the tool. So, the rack profile was defined by a pole symmetric parabolic-type function, which in turn defined the path of contact and finally gears with an arbitrary number of teeth. Many applications were developed with S-gear shape, e.g., helical, c...
2019
In this current Research explores the impacts of modifying the tooth profile on the vibration of multiple gear sets. The nonlinear analytical model takes into account the dynamic load distribution between the individual gear teeth and the impact of variable mesh stiffness, profile changes and loss of frictional contact. Compared to nonlinear gear dynamics, the model proposed in this research provides better agreement than two current models. The noise mechanism can therefore be precisely uncovered to noise source, transmission path, and response. The Benchmark contact mechanics in gear mechanisms had compared with various loads, changes to the profile and circumstances of bearing stiffness. This model depicts the complete and partial loss of contact. Based on the suggested model, perturbation analysis discovers approximate frequency response alternatives in the event of no complete contact loss due to optimization. In this work, to increase the speed as well as the torque of the mot...
This paper presents a global optimization method focused on gear vibration reduction by means of profile modifications. A nonlinear dynamic model is used to study the vibration behavior; such model is validated using data available in literature. The optimization method considers different regimes and torque levels; the objective function can be the static transmission error or the maximum amplitude of the gear vibration in terms of dynamic transmission error. The procedure finds the optimal profile modification that reduces the vibrations over a wide range of operating conditions. In order to reduce the computational cost, a Random-Simplex optimization algorithm is developed; the optimum reliability is estimated using a Monte Carlo simulation. The approach shows good performances for the computational efficiency as well as the reliability of results. Finally, an application to High Contact Ratio (HCR) gears is presented and an extremely good performance is obtained by combining optimization procedures and HCR properties.
Journal of Sound and Vibration, 1996
A comprehensive mathematical model is introduced for analyzing the influence of shape deviations and mounting errors on gear dynamics. Contact conditions for both rigid and deformable solids are used for characterizing the gear set excitation sources. The deformed state is modeled by a lumped parameter non-linear system with six degrees-of-freedom on pinion and gear. Each potential contact line on the base plane is discretized in independent elementary cells of constant stiffness and an original procedure is proposed for simultaneously solving the normal contact problem between active flanks and the equations of motion. Comparisons with several results from the literature prove the versatility of the model as static and dynamic load distributions, transmission errors and mesh stiffnesses can be evaluated from a unified approach. Finally, the interest of the methodology is illustrated by some practical problems in gear dynamics: i.e., the influence of some geometrical errors and the role of linear profile modifications on spur and helical gears.
Gears are one of the most critical components in industrial rotating machinery. There is a vast amount of literature on gear modelling. The objectives in dynamic modelling of gears has varied from vibration analysis and noise control, to transmissions errors and stability analysis over at least the past five decades. The ultimate goals in gear modelling may be summarized as the study of the following:
One of the most important and unavoidable part of each and every rolling machinery is the gears. Gears are of many types and kinds, they are used in watches to colliders. As in the era of mass production and fast movement gears are inevitable, so analysis of gears should be carried out to find the merits and demerits, to correct them and to design new. In this paper we used to review the analysis of gear both in analytic (Hertizian & Lewis) as well as using software(ANSYS) and their comparison. Also the important findings about the properties of gear
Recent Advances in Gearing, 2021
The chapter starts with the theory defining S-gears and their properties and compares S- and involute gears. Most of the text deals with cylindric spur gears. S-gears are defined with the half-symmetric rack profile, which then uniquely defines the path of contact and gears. Reshaping of the gear flanks for external and internal gear pairs is presented here and thermal behavior discussed and compared with the involute gears. Experimental verification of S-gears theory, especially durability and thermal behavior of importance for plastic gears is presented. So, in this chapter a material combination of interest was alloy steel and POM (which was only heat stabilized). The chapter presents some specific information about this. And finally, the planocentric gearbox focused on high-tech industry (e.g., robotics) is presented. The problem is how to achieve required properties. So, all possible analytical tools should be used to minimize backlash and many other parameters which is also pr...
Mechanism and Machine Theory, 2008
A novel cosine gear drive is presented in this paper. The pinion of the drive utilizes a cosine curve as the tooth profile. It takes the zero line of the cosine curve as the pitch circle, a period of the curve as a tooth space, and the amplitude of the curve as the tooth addendum. The generation principle of the cosine gear is described. The mathematical models, including the equation of the cosine tooth profile, the equation of the conjugate tooth profile and the equation of the line of action, are established based on the meshing theory. An example drive in solid model is presented and its computerized simulation is carried out. A few characteristics, such as the contact and bending stresses, the sliding coefficient and the contact ratio, of this new drive are analyzed. A comparison study of these characteristics with the involute gear drive was also carried out in this work. The results confirm that the cosine gear drive has lower sliding coefficients and the contact and bending stresses of the cosine gear are reduced in comparison with the involute gear. application of a spur pinion. The first version was a spur involute pinion and the other version was a pinion that is conjugated to a parabolic rack-cutter. The following advantages of the new design were reported: (i) existence of a longitudinal bearing contact, (ii) avoidance of edge contact, and (iii) reduction of contact stresses. Tsay and Fong studied a helical gear drive whose profiles consist of involute and circulararc. The tooth surfaces of this gearing contact with each other at every instant at one point instead of one line. The bearing contact of the gear tooth surface is localized and the centre of the bearing contact moves along the tooth surface. Thus, this helical gear drive is insensitive to centre distance variation and gear axes misalignment. Komori et al.
2019
In modern industry, the design process of most mechanical components is aimed at reducing their mass and increasing the performance, especially in weight-critical applications like aero-space engines. This approach often results in components that can have resonances in the operative range that could cause excessive vibrations and a consequential reduction of the life of the component itself. For this reason, a modal analysis check is always performed and the design process is iterated until also the dynamic behavior is acceptable. However, this approach is non-optimal, as not all resonances are excited during operation. Hence a design process that aims also to reduce the real dynamic response is proposed in this paper. By changing the geometry of thin-webbed high speed helical gears the dynamic response is altered to modify the mode shapes to obtain ones that are non-excitable by the external forces in the operative range, thus greatly improving its dynamic response. The original c...
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Current and continuous increase in high performance aerospace transmission requirements need to be systematically approached from a dual point of view; deeper modelling capabilities of gear meshes and more reliable stress prediction analyses have to cope with finer gear materials strength characterisation.
IRJET, 2021
Gears are one of the most critical components in power transmission systems. It may be used in a variety of industrial machinery. The bending strength of the gear tooth is main contributors for the failure of the gear. In design of gear system the calculation of bending strength is an important part. The complicated dynamic forces at the gear meshes are the source of vibration and result from parametric excitation and tooth contact nonlinearity. The primary goal of this work is to develop mathematical models for gear with nonlinear and analytical studies of nonlinear and dynamic behaviors.
A Gearbox is a mechanical device that is used to provide Speed and Torque conversions from a rotating power source to output shaft. As the speed of the shaft increases, the torque transmitted decreases and vice versa. Gears are an integral and necessary component in our day to day lives. The field of gear design is an extremely broad and complex area, and a complete coverage in any research work is not possible. They are present in the satellites we communicate with, automobiles and bicycles we travel with. This paper presents the designing of the different gear on geometric conditions and finding the effect of tooth load. The present work describes the development of such a design methodology and diagnostic tool for determining the modes of failure for spur gear
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