Gear Module Research Articles

Assessment of the Uniform Wear Bending Strength of Large Modulus Rack and Pinion Pair: Theoretical vs. Experimental Results

Due to long-term operation under low-speed and heavy-load conditions, large module gears and racks are inevitably subject to tooth surface wear. To investigate the changes in gear tooth bending strength, the Three Gorges ship lift was taken as the research object and a simulation test bench was established. An analytical method, a finite element method, and an experimental method were utilized to analyze the bending stress of gears under normal and various uniform wear conditions. The obtained results revealed that with the increase in wear degree and load, the bending stress of single-tooth meshing was significantly higher than that of double-tooth meshing, and the single-tooth meshing time also increased, which indicates that gear wear accelerated the process of performance degradation. Furthermore, the relative errors obtained by the three calculation methods were all at a low level. This investigation aims to provide a solid theoretical and experimental basis for the dynamic analysis of large module gear and rack transmission.

Performance improvement of set of worm gears used in soot blower through profile modification

The present design of a set of worm gears used in a soot blower produced by a certain manufacturer has an efficiency of 68.8%. A soot blower is one of the most critical components in industrial applications for removing the large amounts of soot generated by boilers and is required to be operational 24×7. The energy consumption of the soot blower depends on its working efficiency and ultimately the design of its set of worm gears. This paper focuses mainly on the design and analysis of available industrial worm-gear sets used in soot blowers. The theoretical, experimental, and finite-element analysis approaches are validated for the stability of the worm gear set under typical input conditions. This paper also describes an analytical design of experiments (DOE) approach to identify the most significant factor for performance (efficiency) improvement and suggests some design improvements for the worm gear set using the profile modification approach. These ensure the efficiency improvement of the current industrial design of the set of worm gears used in a soot blower. The analytical DOE approach helped identify that the number of worm wheel teeth (Z2) and gear module (m) are the two most significant factors affecting performance. Accordingly, based on the improved design, the final efficiency increased from 68.8% to 74.6% (∼8.5% increment), resulting in lower power consumption during industrial application.

A multidirectional pendulum kinetic energy harvester system for low-power appliances in new energy buses

Wireless sensors play a crucial role in vehicle operations. The effective energy harvesting for self-powering these sensors has emerged as a critical area of interest in recent years. This paper presents a multidirectional pendulum kinetic energy harvester system (MP-KEHS) designed to power low-power sensors in vehicles. The MP-KEHS consists of four main components: an energy capture module, a motion transfer module, an energy conversion module, and an electric energy storage module. The energy capture module, comprising a mass ball and a turntable, captures omnidirectional inertial kinetic energy during vehicle acceleration, deceleration, and turning. In the motion transfer module, a one-way gear module converts the multidirectional rotations of the energy capture module into unidirectional rotations, while the planetary gear train enables speed coupling during simultaneous vehicle acceleration and turning. The energy conversion module utilizes a generator to transform rotational kinetic energy into electric energy. The electric energy storage module stores the electric energy in a supercapacitor after passing through a voltage regulator circuit, providing power to low-power devices. Using of multi-body dynamics software and Simulink, the swing angle of the mass ball was determined under four real driving cycles. Experimental results demonstrated that the average output power of the MP-KEHS reached 116.8 mW. Charging the capacitors of 220 μF, 470 μF, and 1000 μF from 0 V to 1 V takes 8 s, 24 s, and 93 s, respectively. Finally, the MP-KEHS was applied to a bus on the Liaocheng University campus, achieving an average output power of approximately 176 mW, which satisfied the power requirements of the sensors. These findings indicate that the MP-KEHS effectively harnesses the vehicle's otherwise wasted inertial energy, enabling wireless sensor self-powering.

STUDY OF THE GEAR CUTTING PROCESS BY THE RADIAL-CIRCULAR METHOD

The results of the study of the radial-circular method of gear cutting are presented. The cutting and shaping of teeth is carried out by a thin disc cutter under conditions of continuous generating, with a combination of axial feed of the cutter and its constructive radial movement due to eccentric installation on the spindle axis. The value of the eccentricity is determined by the gear module. A graph-analytical model was used to calculate the parameters of the cuts, and the cutting force and torque on the cutter axis were modeled using these data. It was found that the cutting process is characterized by significant load variations. The areas of maximum tool wear were predicted. It is shown that for under the same initial conditions, the cutting time using this method is two times less than the time of hobbing. Since a disc cutter can cut gears in a wide range of modules, this process is one of the most versatile. This method opens up great possibilities for the restoration and repair of gears and drives manufactured to standards other than those adopted in Europe.

Transmission error compensation method for small module gears of CNC machine tools based on discretization decoupling calculation

Transmission error compensation method for small module gears of CNC machine tools based on discretization decoupling calculation

Wear analysis and simulation of small module gear based on Archard model

With the development of micro machining technology, small module gears are widely used in the field of high precision technology. In view of the failure problems such as tooth fracture and fatigue pitting caused by dynamic wear in the process of small module gear transmission, this paper takes a micro planetary gear reducer as the research object and establishes the analysis framework of small module gear wear calculation model based on Archard wear model and Hertz contact theory. Considering the influence of installation error and position tolerance, tooth contact analysis (TCA) model of small module gear is established based on the theory of small displacement torsor (SDT) and space coordinate transformation, and the impact of these errors on the dynamic contact trajectory, contact stress, and tooth surface wear is analyzed based on the numerical simulation. The numerical simulation results show that with the increase of the installation error, the contact trajectory will deviate significantly, which will finally result in increased contact stress and wear. Moreover, with the decrease of tolerance level, the service life of the device increases under the same reliability level. The above analysis of tooth surface wear can provide references for the design and installation of a small module gear transmission.

Duplex Scheme of the Technological Impact of the Provision of Operational Properties of a Hardened Large Module Gears

The two-level circuit of technological influence of providing of operating properties of hard-tempered large module gears is offered on basis division of tasks of technologist and designer with regulation of complex parameters on each of these stages and subsequent decision of task of choice of optimum value of operating properties.

Effect of the Number of Teeth on the Structural Integrity of Gear Shaft base on Finite Element Method

Gear shaft is an indispensable component in many dynamic mechanical systems including automotive drive systems, turbine systems, and industrial manufacturing machines. Precise control of the structural integrity of gear shaft with different number of teeth is crucial to the safety and reliability of its application in mechanical systems. In this paper, finite element method (FEM) is adopted to instigative the effect of changing the number of teeth on the strain and deformation of a series of spur gear shafts. Firstly, a mesh type dependence simulation is conducted to determine the appropriate mesh type for finite element analysis (FEA) of gear shaft. Secondly, a mesh size sensitivity test is performed, which determines the suitable mesh size. After the precise FEM is determined, strain and deformation simulations are carried out based on a gear shaft series with gear module 1.5 and number of teeth ranging from 10 to 13. The simulation results demonstrated that increasing the teeth number increases the maximum strain of the gear shafts while decreases the maximum deformation. The results are coherent with the change in gear shaft geometry with the change in teeth number.

Theoretical transmission analysis to optimize Gearbox for a 2.6 kW automatic pepper transplanter

A gearbox is an essential component of an automatic transplanter to transmit engine power to the transplanter components. It is necessary to find the appropriate gearbox dimensions and materials for the pepper transplanter to minimize transmission losses. Therefore, the objectives of this research were to simulate the power transmission efficiency of the gearbox, and to determine a suitable number of stages, and materials and the dimensions of the spur gears. A 2.6 kW gasoline engine was considered as the prime source to power the entire transplanter. The available maximum length between the engine and transplanter subsystem was 422 mm. By considering design issues, a simulation model was created to determine the efficiency of the pepper transplanter gearbox, including various types of mechanical losses in the gearing system. Three different modules (1, 2, and 3 mm) and two materials were used to evaluate the effects on transmission. The analysis results indicated that the gearbox transmission efficiency levels of seven to twelve stages were in the range of 93.0–98.7%, whereas the eight-stage gearbox yielded the maximum efficiency of 98.7%, greater than our target efficiency of 98.0%. Therefore, an eight-stage gearbox was selected for power transmission to the components. The power transmission simulation results showed that the overall efficiency from engine to transplanting mechanism shaft varied in range of 95.2–95.9% owing to contact of the gear meshes. The analysis results also indicated that the 25CrMo4 carbon steel material with a 2-mm module gear was appropriate for the pepper transplanter. The analysis in this paper can be used as reference in the design of pepper transplanter gears and gearboxes with suitable material properties to provide the desired efficiency.

Uncertainty determination of a novel single flank rolling test facility for micro spur gears

Micro gears are particularly complex to manufacture in many respects, as their deviations are relatively high concerning their component size. In addition, tolerance specifications of common gear standards are currently not defined for small gear modules. To make a quantitative statement about the rolling behavior of a micro gear, the single flank rolling test is considered, since this method can provide information about the functional behavior of a gear. This novel approach investigates a single flank rolling test facility for micro spur gears specifically developed for this application and evaluates measurement uncertainties of single flank rolling deviation parameters. After a detailed description of the test facility, a task-specific measurement uncertainty budget is developed based on the experimental structure of the measuring instrument. Intensive experiments revealed expanded uncertainties of less than 1.5 µm. In addition, a process suitability analysis of the measurement system was carried out, which was proven for all investigated gear deviation parameters by extrapolated standard tolerances. This demonstrates that single flank rolling tests on micro gears with low measurement uncertainties are technically possible and forms a basis for further investigations in quantifying uncertainties of micro test facilities.

Lightweight design of the planetary gear reducer of reduction drive hub motors

Hub motor is the development direction of new energy vehicles in the future. Usually, the reduction drive hub motor is directly arranged in the narrow rim space, so there are strict restrictions on the volume and weight of its reducer. This paper presents a highly integrated transmission scheme which can improve the working life of the reducer. For the planetary gear reducer integrated by the reduction drive hub motor, a multi-objective optimization function with minimum volume and large coincidence degree is constructed. In terms of constraints, the necessary conditions of planetary gear transmission are fully considered, the gear module meets the requirements of national standards, and the strength conditions of gear transmission. Using genetic optimization algorithm, the optimal solution satisfying the constraints is obtained. The optimization results show that the coincidence degree of the engagement between the sun gear and the planetary gear increases by 67% and the equivalent volume decreases by 31%, which can reduce the volume and reduce the transmission noise at the same time.

Analysis of Planetary Gear Transmission Characteristics Based on ANSYS

Planetary gear transmission is widely used in roadhead, crane and other transmission equipment, its reliability and stability are related to the service life and work efficiency of equipment, but the current research on planetary gear transmission device is not comprehensive, lack of accurate analysis of gear meshing process load. Therefore, in this paper, ANSYS software as a platform, through the construction of dynamics module, to solve the gear teeth surface, gear teeth root and gear teeth tip stress analysis and deformation and displacement, the finite element analysis. The research results provide necessary technical support for the design and production of planetary gear transmission.
 Aims: Through finite element analysis of planetary gear transmission, the dynamic parameters of planetary gear transmission are solved, and the reliability and stability of planetary gear transmission equipment are improved.
 Study Design: By constructing the dynamics module of planetary gear, the stress analysis, deformation and displacement of gear tooth surface, gear tooth root and gear tooth top are solved, and the finite element analysis is carried out.
 Place and Duration of Study: North China University of Water Resources and Electric Power, from March to July 2022.
 Methodology: The finite element analysis was carried out on the model of planetary gear transmission mechanism, and the model was established and simplified by using SolidWorks software. The modal analysis and dynamic analysis were carried out by using ANSYS software, and the meshes were divided and constraints were added. Finally, the parameters such as stress, strain and displacement of the meshing position were solved.
 Results: The result of model meshes is 357575 units and 204871 nodes. The algorithm has 219 iterations and 15 convergence points. The experimental results show that there is a meshing position with the worst contact fatigue strength in the contact area between the outer ring gear and the planetary gear tooth surface. At this position, the contact stress value of the tooth surface is 22626Pa.
 Conclusion: In this paper, the planetary gear device is modeled by SolidWorks software, and the finite element analysis is carried out by ANSYS software to obtain the stress and strain parameters in the transmission process of the device, as well as the worst meshing point of the gear, the most vulnerable point of fatigue and other dangerous points. It lays a certain technical foundation for the optimization and improvement of gear and the design and production of planetary gear transmission device.

Evaluation of the degree of abrasive particles activity in oil of machine units involved in the wear process of toothed wheels

This article discusses the regularities of changes in the activity of abrasive particles in the oil of machine units participating in the process of gear-wheel wear at constant and increasing concentrations. They vary depending on the number of loading cycles of gear teeth, considering the share of crushed abrasive particles in one loading cycle of the gear teeth. This makes it possible to obtain regularities in the change of concentrations of active abrasive particles in the oil depending on the gear modules and the number of loading cycles, taking into the account the fraction of crushed abrasive particles per cycle of loading the gear. This technique can be used to determine the duration of the test of the gear wheel material on samples at a constant total concentration of abrasive particles in the oil change for the units of machines with gear drives operating in the presence of abrasive particles in the working environment. The case under consideration corresponds to the operating conditions of the gear transmission in the unit, which allows calculating the oil change period in the units of machines operating in an abrasive environment.

An experimental investigation of windage and oil churning power losses of gears and discs

This study presents comparable sets of churning and windage power loss measurements of a gear. Measurements are performed under windage (air only) and churning (immersion in oil up to a certain level) to quantify load-independent power losses of a family of spur and helical gears along with representative discs. Aiming at quantifying the impact of gear geometry on churning or windage losses to establish a baseline for the case of no enclosures around the gear, the test matrix is designed to investigate three key items: (a) contribution of losses along the periphery and faces, (b) the influences of gear teeth versus a toothless replacement disc as well as key design parameters (gear module and helix angle), and (c) a comparison of churning and windage power losses measured from the same exact set-up. The churning power losses are shown to increase with the static oil levels due to increased solid-fluid interactions. The impact of oil bath temperature (oil viscosity) on churning loss is observed to be more pronounced for higher oil levels. The presence of gear teeth on the rotating specimen (spur or helical) cause churning loss to increase modestly in comparison to the disc specimens. Furthermore, a larger tooth size results in higher churning power losses. The influence of gear teeth (gear vs. disc) on windage loss is shown to be significant, indicating that modeling a gear in a high-speed windage condition as a cylindrical disc might not be an acceptable practice.

CFD-vibration coupled model for predicting cavitation in gear transmissions

Cavitation occurs in gears during transmissions at high speeds, making it a major obstacle in the development of high speed and high accuracy gear trains. However, there has been limited research to study the cavitation mechanism. This paper reports on a computational fluid dynamics (CFD) model coupled with gear vibration developed to investigate the vibration-cavitation mechanism. First, a finite element model is employed to obtain the characteristics of gear vibration, which are imposed on the CFD model boundary during the dynamic flow analysis. For the cavitation simulation, the Zwart–Gerber–Belamri model is employed in conjunction with the k-ε turbulence governing equations. Subsequently, the CFD-vibration coupled model is validated by comparing with experiments. Finally, the distributions of vapour and pressure in the meshing region are presented, and the effects of rotational speed, torque, gear module, and lubricant viscosity are discussed. Moreover, the evolutions of vapour and pressure on the tooth meshing face are analysed. The results show that cavitation is aggravated at high speeds, low loads, high gear modules, and low viscosities, and extreme pressure fluctuations occur at the pitch point. Therefore, this study provides a valuable tool for optimizing high-speed gear transmission systems.

기어시스템에서 설계변수에 따른 전달오차와 물림강성 해석

The gear has a wide range of transmitted force as various gear ratios are possible using a combination of teeth. It can transmit power reliably and cause relatively little vibration and noise. For this reason, the application of reducers of electric vehicles is being expanded. Vibration noise generated from gears is propagated into the quiet interior of a vehicle, causing various claims. In most gear studies, transmission error has been pointed out as the main cause of vibration noise of gears. Transmission errors have various causes, including design factors, manufacturing factors, and assembly factors. In general, when predicting transmission error through finite element analysis, design factors play an important role without considering manufacturing factors or assembly factors. In this study, relationships among important design variables (gear module, compensation rate, load torque, and transmission error) in gear design were investigated using analytical and experimental methods. In addition, a method of predicting gear meshing stiffness through the predicted gear transmission error was proposed to obtain variation of meshing stiffness due to changes of gear design parameters.

Prediction of machining deformation and reasonable design of gear blank for split straight bevel gear

The deformation of gear blank is serious in the machining process of the split straight bevel gear, considering the material and the design of gear blank, the relationship between the change of additional stress and bending deformation of gear blank is studied, and the calculation model of the internal additional stress and additional torque during the gear cutting is established. According to the moment-area method, the calculation formula of the bending deformation of gear blank is derived, and combined with the time-varying stiffness, the mathematical model of the gear blank deformation is obtained. The theoretical calculation, finite element analysis, and experimental results are highly consistent. Based on the above research, the internal relationships between the machining deformation and the geometric parameters such as the thickness, diameter, and gear module of the split gear blank are analyzed, and the reasonable design of the geometric parameters of the split gear blank and the reasonable dividing law of the gear blank are explored.

Model and Characteristic Simulation Analysis of a Two-Speed Transmission System

One of the main tasks in the research of a helicopter two-speed transmission system was to improve its dynamic characteristics. For the low gear mode of the system, a dynamic model was established by using the lumped parameter method, the method of Runge-Kutta was used to solve the nonlinear dynamic system equations. The effect of the gear module on the dynamic transmission error, dynamic load of the gear pair and the dynamic windup angle of a one-way clutch were studied. And the effect of the one-way clutch torsional stiffness on the dynamic transmission error and dynamic load of the gear pair was also studied. The results show that: 1)~the dynamic transmission error of the gear pair decreases and the dynamic load of the gear pair increases with the increase of the gear module at the lower range of excitation frequencies; 2)~the dynamic windup angle of the one-way clutch increases with an increase of the gear module. 3)~the dynamic transmission error of the gear pair and the maximum dynamic load increases with an increase of the one-way clutch torsional stiffness at the lower and medium range of excitation frequencies. The above results can provide reference for the subsequent upgrade and improvement of the two-speed transmission system.

Effect of gear design on the power transmission unit of a small-sized multipurpose agricultural utility vehicle

In this study, various gears were designed and evaluated to analyze the power transmission efficiency of a multipurpose agricultural utility vehicle. A computational simulation method was used to evaluate the effect of different models of power transmission systems before developing the vehicle. The 3D models of 15, 18, 21, 24, 27, and 30 teeth spur gears were generated using SM45C steel using commercial software. The power transmission efficiency was analyzed by varying the gear teeth number, face width of the gear teeth, and estimated torque values. The gear modules of 3.2, 2.7, and 2.2 mm were used to model the spur gear train using the 1:1 gear ratio. The power transmission efficiency of the proposed utility vehicle was simulated using 5, 10, and 15 Nm of torque. The simulated results of the 3.2 mm gear module with 30 teeth spur gear showed better performance with maximum power loss compared to other gears. The maximum power transmission efficiency was recorded to be 99.94% when adjusted for 15 Nm torque. The designed gears with 25 mm and 15 mm face width achieved 99.90% and 99.92% transmission efficiency, respectively. It was observed that gears with smaller face width achieved better efficiency with minimal power loss. The simulation results presented in this study is suitable to design and develop a utility vehicle for multipurpose agricultural use.

РАЗРАБОТКА МИНИМАЛЬНО ЛЕГИРОВАННОЙ КОНСТРУКЦИОННОЙ СТАЛИ ДЛЯ КРУПНОМОДУЛЬНЫХ ЗУБЧАТЫХ КОЛЕС ТРАНСМИССИЙ

In the world practice of manufacturing gears for automotive equipment, a search is being made for new, more effective steel grades and ways to realize their advantages, achieved both during smelting and during further thermal, deformation and chemical-thermal treatment. There is a tendency to reduce the nickel content in structural steel grades and replace them with sparingly alloyed, microalloyed with strong carbide-forming elements. The condition for using sparingly alloyed structural steels is the ability to find a compromise between increasing the reliability and durability of machine parts and saving deficient alloying materials. Based on this, the article formulates the main provisions that should be taken into account when developing minimally alloyed structural steel compositions for manufacturing highly stressed gears of mobile machine transmissions. It is shown that the introduction of new sparingly alloyed steel grades leads to the need to develop new technologies with the solution in each case of the problem of assessing the impact of alloying elements and microadditives on the hardenability of steel. The method of minimum doping of steel for gears with a module of 10 mm is given. Based on the application of a new approach, a new minimally alloyed structural steel has been developed that provides high strength, fatigue and technological characteristics of large module gears. The hardenability of the core and cemented layers of the developed steel is determined, which provides the life of the gears for at least 1,000 hours in operating conditions at contact stresses in the engagement pole σН = 1,800 MPa.