Tooth Gear Research Articles

The Concept of Technological Support of Operational Properties Based on Stabilization of Mechanical Properties of Gear Materials in a Gas Turbine Engine Drive System

Modern production of gears for gas turbine engines for aviation, marine and land use is inherently related to the calculation of the stress state of the working surfaces of the mating teeth. To create conditions for the operability of the gear train and the drive system as a whole, an engineering analysis of the contact endurance of the mating surfaces is a necessary criterion. The contact strength determines the life of the gear mechanism. The value of the contact strength, taking into account its distribution in the contact zone of the working mating surfaces of the gears, is determined by the processing technology and operation, but the mechanical properties and texture of the material have the greatest influence. This determines the requirements for the stability of the mechanical properties of the materials used for the manufacture of gears, making a topical question on their study. The technology of manufacturing the gears in the gas turbine engine drives forms the layer structure of the toothed crown because of the use of chemical-thermal treatment. The surface hardened layer of the gear tooth after chemical-thermal treatment is saturated with carbon and nitrogen, and as a result of thermal action acquires mechanical properties and structure different from the material in the supply. The paper presents the results of practical research of evolution of mechanical properties of structural steels 20H3MVF-Sh, 18H2N4MA, 16H3NVFM-Sh and 12H2N4A-Sh based on various types of chemical-thermal treatment, as well as microstructure of toughened layer and core of the part. The steel mechanical properties stabilization evaluation in the process of gear technology was performed. The presented results of experimental studies of mechanical properties of the material prove stabilization of mechanical and structural indicators, which are responsible for the contact strength of the mating surfaces of toothed gears.

Evaluation of Scuffing Load Capacity of Helical Gear Based on the Tribo‐Dynamic Model

ABSTRACTThe scuffing load capacity of gear is closely related to the meshing temperature rise of tooth surface. The key to predict the temperature rise is to establish an accurate meshing temperature rise model. In the paper, a tribo‐dynamic model of helical gear is established through coupling of tooth surface lubrication parameters, and the influence of temperature rise on ambient temperature during meshing process is considered. Then, the effects of oil supply temperature, input speed and torque on tooth surface temperature rise, film thickness, friction excitation and gear dynamic characteristics are discussed. The results show that the temperature rise of the gear is higher during the engaging‐in and engaging‐out regions. Meanwhile, there is local high temperature at the end of the contact line due to the end effect. The vibration of gear along the off‐line‐of‐action direction is mainly determined by friction excitation. With the increase of oil supply temperature, input speed and torque, the risk of scuffing failure increases and the influence of oil supply temperature and input load is more significant. The conclusions of this paper may provide some valuable suggestions for the anti‐gluing failure design of gear in engineering.

Manufacturing design of plain milling technology of spline shaft by formed disc-type milling cutter

Abstract The spline fittings are widely used in different mechanical constructions where high load transmission is required from a shaft to a spline plate or a tooth gear or other internal cylindrical element. In many cases a key joint connection can not bear the load that we want to transform. In this case the application of double key could give solution. But sometimes it does not give solution due to the high load that is why spline fitting should be used. This publication focuses for the manufacturing of the spline shaft with plain milling technology. The type of the tool is a formed disc type milling cutter. Since more splines are around the perimeter of the shaft the repetition of the milling process is needed in the function of the number of the splines. All of the manufacturing parameters will be determined that are needed for a complex technological analysis such as cutting forces, machining times, speeds, etc. The chip volume will be approximated by volume constancy since the separated chip volume is a quite complex geometric body. I will prescribe initial technological parameters and define existing shaft geometries for which I will determine the technological parameters to show and analyze the correlations between the technological parameters and the variable for each shaft.

Modeling and Simulation of the Induction Hardening Process: Evaluation of Gear Deformations and Parameter Optimization

This study aimed to analyze and optimize the thermal induction hardening process applied to toothed transmission gears, focusing on thermal aspects, structural deformation, and topology optimization, while exploring the feasibility of various materials and operating conditions. The research simulated thermal and deformation behavior using a computer model, comparing results with experimental data through the Ansys® platform 2022 R1. The methodology encompassed thermal and deformation analyses, topology optimization to identify removable regions without compromising part integrity, and a sensitivity study to evaluate the different materials and operating conditions. This study validates the precision of computational models in predicting thermal and deformation behavior in toothed gears under thermal induction hardening, introducing topology optimizations and alternative materials, and providing novel perspectives for the more efficient and cost-effective manufacturing of these components. Comparative thermal analysis revealed a maximum relative error of less than 6% between temperatures from the computer model and experimental results, while deformation comparisons exhibited a maximum relative error of less than 7%, affirming the simulation model’s accuracy in predicting and managing deformations within acceptable thresholds. Topology optimization successfully pinpointed removable regions without compromising structural integrity, enabling the production of lighter and more economical devices. Future endeavors should concentrate on additional tests to verify the feasibility of reducing power and cooling temperature without compromising product specifications. Furthermore, it is advisable to explore alternative materials and apply the developed methodology in diverse industrial settings to generalize the findings and amplify the impact of the proposed optimizations.

Gear Fault Detection Method Based on Convex Hull Clustering of Autoencoder’s Latent Space

This paper presents a method of pitting failure detection in toothed gears based on the reconstruction of the gear case vibrational signal. The effectiveness of the proposed method was tested in an experiment on a power circulation test stand. The autoencoder deep neural network architecture, semi-supervised training, and validation, along with the latent data convex hull-based clustering, are presented. The proposed method offers high efficiency (0.99 F1-measure) in gear state prediction (100% in failure detection, 98.9% in normal state prediction) and provides more capabilities in terms of generalization in comparison with linear machine learning techniques such as principal component analysis and nonlinear like the generative adversarial network. Moreover, it is distinguished by high sensitivity while also being able to detect even slight surface damage (initial pitting). These findings will be of particular relevance to a range of scientists and practitioners working with gear drives who are willing to implement machine learning in signal processing and diagnosis.

Research of the influence of element deformation and manufacturing errors of planetary gears on the load distribution among satellites

A technologically advanced multi-satellite design of a toothed planetary gear is studied, in which the carrier is made in the form of two cheeks, which are connected to each other by the axes of the satellites, which act as jumpers. The problem of the stress-strain state of mating elements is solved using differential equations of the curved axis of the satellite, represented by a beam on an elastic foundation. The distribution of the load across the satellites is determined taking into account the deformation of the gear segments and the non-adherence of the gear teeth caused by errors in its manufacture. Keywords:planetary gear, non-rigid carrier, compliance of segments, load distribution Alexandrsun4009@gmail.com

Research on Noise Reduction Modification Design of High Speed EMU Traction Arc Toothed Cylindrical Gears

Aiming at the deficiencies of the traction helical gear transmission system when the EMU is running at high speed, this paper proposes and designs a kind of arc toothed cylindrical gear adapted to the traction of higher speed EMU. A parametric arc toothed cylindrical gear model was constructed using CREO, and its dynamic contact characteristics and acoustic response characteristics were analyzed under sustained operating conditions using the finite element boundary element method. The design of a tooth profile combined with the radius of the arc toothed line of the comprehensive trimming program put forward a virtual trimming prototype method through MATLAB and CREO reconstruction gear, and trimming before and after the gear transmission simulation experiments occurred for comparison and analysis. This study shows that the traction arc toothed cylindrical gear comprehensive modification method proposed in this study achieves better dynamic performance optimization, effectively reduces the contact stress and radiation noise of the gear transmission, and provides a theoretical basis for the development of a new generation of high-speed EMU stock traction drive systems.

DETERMINATION OF POWER LOSSES DUE TO PERIODIC COMPRESSION-EXPANSION OF THE OIL-AIR MIXTURE BETWEEN THE TEETH OF GEARS. PART 1. MATHEMATICAL MODEL

The simultaneous contact of two pairs of teeth between their active profiles creates a closed volume of the oil-air mixture. Reducing this volume leads to the occurrence of such a negative phenomenon as periodic compression and expansion of the oil-air mixture in volume. At high gear rotation speeds, a significant increase in the pressure of the oil-air mixture is observed and, as a result, additional vibration of the gearing occurs. The oil-air mixture outflow rate can reach the speed of sound, which causes additional noise during gear operation, and at high rotational speeds, a hydraulic shock occurs in the space closed between the pinion and gear teeth, resulting in cavitation. By representing the helical gear as a set of spur gears displaced relative to each other in the tangential direction, it simplified the mathematical model to describe thermodynamic processes in a series of isolated cavities. The following variants are considered: a) the first cavity in the direction of engagement is connected to the environment on one side and to the next second cavity on the other side; b) some i-th cavity is connected to the cavities i - 1 and i + 1, respectively; c) the edge cavity N is connected to the previous cavity N - 1 and the environment. Thus, a mathematical model of the periodic compression-expansion of the oil-air mixture in the space closed between the teeth is presented, which considers the cross-sectional areas of the axial and radial flows of the oil-air mixture, the ambient pressure of the space closed between the teeth, the velocity of the radial flow of the oil-air mixture, the instantaneous volume of the elementary cavity closed between the teeth, and the current pressure in the cavity. Keywords: power losses, oil-air mixture, periodic compression-expansion, toothed gears, mathematical model, hydrodynamic model

Wear characteristics analysis of variable hyperbolic circular-arc-tooth-trace cylindrical gear transmission considering assembly error theory

Wear is the main failure form of the gear transmission interface, runs through the whole life cycle of gear service, and the distributed error of the tooth surface due to the introduced assembly error will make the actual meshing state of the tooth surface different from the ideal meshing state, thus affecting the tooth surface wear trajectory and state. Therefore, considering the coupling relationship between assembly error and tooth surface contact analysis, the variation laws of the wear amount of the gear transmission interface of the variable hyperbolic circular-arc-tooth-trace cylindrical gear were studied under the consideration of assembly error in this article. Based on the tooth surface contact analysis method and Hertz contact theory, the transient linear load, the combined radius of curvature, the length axis and short axis of the contact ellipse, and the instantaneous sliding velocity were calculated. Through revising the calculation method of adhesive wear of variable hyperbolic circular-arc-tooth-trace cylindrical gears, the correlations between the tooth surface wear amount and gear parameters of variable hyperbolic circular-arc-tooth-trace cylindrical gears under different assembly errors were analyzed. The results show that the maximum wear occurs at the root of the tooth, and the wear at the indexing circle approaches zero, whether it is standard installation or non-standard installation. The vertical axial error and horizontal axial error have little effect on the wear, while the center distance error will aggravate the wear. The proposed method comprehensively considers the influence of assembly error and gear parameters on tooth surface wear, and this method can provide a theoretical reference for the design and analysis of anti-wear, wear reduction, and life extension of variable hyperbolic circular-arc-tooth-trace cylindrical gear tooth surface.

Calculation of a roller bearing with tooth gearing

A non-standard roller bearing with tooth gearing is investigated. An analytical method is used to determine the load on the roller, which will lead to frictional-thermal failure of the bearing. The stress-strain state of the loaded bearing is obtained by strength calculation in the ANSYS software. The applicability of a bearing of this design is considered. Keywords: rolling bearing, sliding bearing, satellite, planetary gear, frictional interaction, fatigue failure, durability, strength, ANSYS. epashkov@tpu.ru, ddd6@tpu.ru

Research on the Strength Calculation Method and Effects of Gear Parameters for High-Coincidence High-Tooth Gears

This article studies the calculation method for the tooth root bending stress of a high-tooth gear pair with a high contact ratio. The boundary point of the double-tooth meshing zone of the high-tooth gear pair is used as the loading point for the load, and the calculation formula for the bending stress at the dangerous section of the tooth root is obtained. By using ANSYS finite element simulation, the effect of the addendum coefficient, pressure angle, and other gear parameters on the bending stress of the tooth root is studied. The analysis shows that increasing the pressure angle will reduce the bending strength of the tooth root. Increasing the coefficient of a tooth’s top height will lead to an increase in the bending strength of the tooth root. Comparing the finite element analysis (FEA) results with the theoretical calculation results, the analysis shows that under low loads, the maximum error of the theoretical calculation values of the driving toothed gear and driven gear shall not exceed 13.53% and 15.42%, respectively. Under high loads, the maximum theoretical errors of the driving toothed gear and driven gear shall not exceed 8.78% and 10.91%, respectively. This verifies the correctness of the calculation method, which is of great significance for improving the load-bearing capacity of high-tooth gears and for guiding tooth shape design.

Modelling and Experimental Study of Power Losses in Toothed Wheels

In recent decades, the request for more efficient performances in the aeronautical sector moved researchers to pay particular attention to all the related mechanisms and systems, especially with respect to the saving of power. In this context, the bearing modeling and design, as well as gear coupling, play a fundamental role. Moreover, the need for low power losses also concerns the study and the implementation of advanced lubrication systems, especially for high peripheral speed. With the previous aims, this paper presents a new validated model for toothed gears, added to a bearing model; with the link of these different submodels, the whole model describes the system’s dynamic behavior, taking into account the different kinds of power losses (windage losses, fluid dynamic losses, etc.) generated by the mechanical system parts (especially rolling bearings and gears). As the bearing model, the proposed model is characterized by high numerical efficiency and allows the investigation of different rolling bearings and gears with different lubrication conditions and frictions. A comparison between the experimental and simulated results is also presented in this paper. The analysis of the results is encouraging and shows a good agreement between experiments and model simulations, with particular attention to the power losses in the bearing and gears.

Structural health dynamic monitoring for gear transmission based on guided waves

The rotating machinery has a wide range of applications in many fields. The gear transmission system is one of the key structures of rotating machinery. Once the failure occurs to the gear system, it will destroy the equipment itself and lead the whole industrial production to break. Thus, it is necessary to directly monitor the health condition of the gear system under static and running working conditions. Guided waves method is a technology which has been widely used in the field of structural health monitoring. In this paper, guided waves technology is innovatively applied to the condition monitoring of gear system, which realizes the gear structure direct monitoring for low speed rotating machinery. The piezoelectric transducers integrated with the SMART Layer were placed near the gear mesh region for the direct health monitoring. The feasibility was verified by the guided waves monitoring experiments in a fixed-axis spur gear transmission system. The tooth wear and gear crack were monitored by guided waves under a single working condition. In addition, the stability verification experiment of guided waves was also performed under various low-speed working conditions. To characterize the propagation of gear faults, considering the characteristics of guided waves, a modified health indicator extraction methodology is proposed based on permutation entropy. The results indicated that the guided waves technology has fantastic potential applications in gear transmission system dynamic direct health monitoring.

Restoration of a tractor part by the method of electric arc metallization

Relevance. Tractors are distinguished by long inter-service ranges and easy maintenance. But if the tractor components are not serviced in a timely manner (oil change, filters, and so on), the resulting contamination will begin to damage the parts, and increased friction will contribute to their wear and overheating. Since there is currently an acute shortage of original spare parts and their prices are quite high, the development of technological solutions for the restoration of worn-out seats of tractor parts is relevant. One of the coating methods, namely electric arc spraying, can solve this problem. The purpose of the study: using the example of the drive axis of a cylindrical straight tooth gear of a “John Deere” tractor, develop a technology for restoring a worn-out seat by electric arc spraying for the installation of a bearing or an oil seal. Methods. The brand of the axis material corresponding to the Russian analogue has been determined. The hardness of the axis base was measured with a TK-2M hardness tester. Preliminary mechanical treatment of the restored surface has been carried out. Additionally, jet-corundum treatment of the worn surface was carried out. The technology of electric arc spraying has been applied to obtain the necessary coating. Turning of the restored surface was performed until the nominal diameter of the axle seat was obtained. Results. The technology of restoration of the axle seat by supersonic electric arc spraying has been developed. The expediency and necessity of preliminary mechanical action on the seat, consisting in threading and jet-corundum processing, before the process of supersonic electric arc spraying are established. The results of the study showed the effectiveness of the electric arc spraying method for restoring the worn-out seat of the drive axis of a cylindrical straight tooth gear in tractors. The cost of restoring one worn-out axle seat was 3,000 rubles, which is more than 10 times cheaper than the original spare part. At the same time, all the mechanical properties of the part have been preserved. It is recommended to use the method of electric arc spraying to restore the worn-out seat of the axles of all imported agricultural machines.

Probability estimate of the strength reliability of toothed wheel gear

An improved calculation method for the strength reliability of surface-hardened cylindrical gears, based on determining the probability of safe operation of the gear is presented in the paper. The calculation of probability of fault-free operation according to the criterion of depth contact endurance is implemented and the tools of non-parametric statistics are applied. When calculating contact stresses, the twist angle caused by deformations of the shafts gear is taken into account. The reliability of the toothed wheel gear was evaluated using the developed technique.

Влияние геометрических параметров на качество зацепления тяговой зубчатой передачи грузового электровоза 2ЭС6

The article presents comparison of the quality of coupling the 2ES6 electric locomotive toothed traction gear when the tilt angle of the teeth on the dividing cylinder changes. Recommendations are given on the possible increase in the tilt angle of the teeth in order to increase the load capacity of the transmission. The influence of displacement coefficients on the quality of coupling is estimated. Models of gears of the 2ES6 freight electric locomotive were created. The comparison of the shape of the teeth for the original and optimized gears is shown.

Формирование упрочненного поверхностного слоя при лазерной резке шестерен зубчатых передач из конструкционной легированной стали марки 40X

Формирование упрочненного поверхностного слоя при лазерной резке шестерен зубчатых передач из конструкционной легированной стали марки 40X

Research on Vibroactivity of Toothed Gears with Highly Flexible Metal Clutch under Variable Load Conditions

The article provides a discussion on a methodology intended for testing of power transmission systems featuring an innovative highly torsionally flexible metal clutch patented by the co-authors of this paper. What this methodology takes into account is the amplitude and frequency analyses discussed in the article, as well as a sensing system based on diverse piezoelectric and magnetic phenomena, the Doppler effect, etc. Both contact and non-contact (laser measurement) methods were used during the tests. The purpose of the tests conducted at the stand, originally designed by the authors in accordance with the methodology proposed, was to evidence that using the innovative and patented, highly torsionally flexible metal clutch makes it possible to reduce the vibrations of multi-stage toothed gears, consequently reducing the forces affecting the gear bearings and those acting at the tooth space, which is to enable the service life of individual components of the power transmission systems intended for mining scraper conveyors to be significantly extended. Based on the studies and analyses performed by the authors, one can observe and conclude that the methodology proposed in the paper makes it possible to use an example of a relatively complex power transmission system in order to examine the relationships between the processes at work, i.e., the decline of the linear vibrations of the gear housing (which is undoubtedly positive in power transmission systems) at the expense of increasing torsional vibrations of the innovative clutch, the latter not to be considered unfavourable to users in the case analysed.

Measurement Method of Temperature of the Face Gear Rim of a Spiroid Gear.

Spiroid gears are used to transfer heavy loads with a significant reduction in input speed. Like most toothed gears, they are lubricated with oil whose physical properties change with temperature fluctuations, affecting the durability and reliability of the gear. Bearing this in mind, gear designers plan systems for measuring oil temperature during gear operation at the design stage. The authors of this paper are of the opinion that, in the case of spiroid gears, it may be insufficient to measure only oil temperature during gear operation. It seems that the working temperature of a pair of mating wheels has a decisive impact on the durability and reliability of the gear. The measurement of oil temperature in a tested gear should be treated as a supplementary measurement with the measurement of temperature on the toothed wheels as the basic measurement. Taking into consideration the above, an innovative test bench was designed and built, making it possible to observe how working parameters of the gear (torque and rotational speed) affect the temperature of the lubricating oil, but most of all, the working temperature of the pair of mating wheels. This paper presents, among others, the results of research on the impact of the rotational speed of the input shaft and load on the distribution of temperature on the toothed rim of the face gear.

Design and Control of a Pneumatic Muscle Servo Drive Containing Its Own Pneumatic Muscles

This article presents static and dynamic characteristics of artificial pneumatic muscles. The research stance and the methodology for their determination are described. A mathematical model of a pneumatic muscle has been proposed, having two inputs—the force generated by the muscle and the displacement of the muscle tip, and one output—the valve control voltage. The quality of object mapping was verified by a mathematical model for various trajectories. Then, the control system for the moment servo drive force was composed of two pneumatic muscles working in opposite directions connected by a toothed belt gear. The servo drive was verified and evaluated.