Gear Research Articles

Development of a diesel engine balancing drive with improved maintenance and regulation capabilities

The design of the balancing mechanism of the 8ЧН26/26 diesel engine is analyzed. A balancing drive with a detachable housing part is developed for maintenance of the mechanism without disconnecting the generator clutch. Keywords diesel, balancing drive, counterweight, bearing, gear wheel, housing

Optimization of energy efficiency and NVH behaviour of a helical gear unit

The goal of this study is to perform a multi-objective optimization of a gear unit in order to improve its performance in terms of mechanical power losses, gear dynamics and equivalent sound power radiated by the housing. All these key performance indicators are closely related to the gear macro- and micro-geometry parameters. Decision variables chosen are the helix and pressure angles as macro-geometry parameters, and the amount and dimensionless roll length of tip relief as micro-geometry parameters corresponding to gear profile modifications. The multi-objective optimization is carried out under geometric and load capacity constraints using the evolutionary NSGA-II algorithm. Various results, observed in the form of 3D Pareto front confirm that improvements in energy efficiency and vibroacoustic performance are antagonistic. Nevertheless, a significant decrease of mechanical power losses is possible without degrading the vibroacoustic performance much. Otherwise, the correlation between the gear dynamic response and the equivalent radiated sound power (ERP) is partial. The minimization of the equivalent sound power radiated by the housing is not equivalent to the minimization of the gear transmission error fluctuation. These results underline the interest of modelling the whole gear unit to optimize its efficiency and NVH behaviour.

Parameter-free parallel fast measurement of fine-pitch spur gears

Parameter-free parallel fast measurement of fine-pitch spur gears

Experimental investigation on abrasive flow finishing of FDM printed polymeric spur gear

Experimental investigation on abrasive flow finishing of FDM printed polymeric spur gear

Investigation of Time-Varying Backlash of Spur Gears in Thermoelastic Coupling Conditions

Investigation of Time-Varying Backlash of Spur Gears in Thermoelastic Coupling Conditions

Crushing of abrasive particles in gearbox oil of tractors operating in dusty environmental conditions

This paper investigates the factors affecting the strength of abrasive particles in tractor gearbox oil operating in dusty conditions. The study focuses on gearboxes with constant mesh gears, categorized into two types based on torque transmission. The research aims to determine the degree of activity of abrasive particles influencing gear teeth wear resistance. A methodology for calculating the possibility of crushing abrasive particles based on their concentration, size, and strength is proposed. The influence of normal force arising from friction torque, rolling bearings, and oil agitation on abrasive particles is also examined. The findings indicate that when gear transmission does not transmit torque, the normal force does not lead to abrasive particle crushing, resulting in high wear capacity in the gearbox oil. However, under the influence of normal force from the torque transmitted by the internal combustion engine, abrasive particles in the tooth contact zone are crushed, reducing their wear capacity. The study’s results contribute to understanding the factors affecting abrasive particle strength in tractor gearboxes operating in dusty conditions, providing insights into improving system design and operation for enhanced durability and efficiency.

Automatic Gear Tooth Alignment in Vision Based Preventive Maintenance

Thorough maintenance of industrial equipment is crucial for the finances of companies. Whereas the purchase of new tools can be an expensive business, reconditioning special gear often costs just a fraction. In this paper, preliminary steps for an accurate visual based preventive maintenance of hobbing wheels are investigated. To perform robust and reliable decisions about the wheel's condition, tool department specialists require precise taken captures of it. For this reason, a visual control cell is built, which depends on correctly aligned hobbing wheels in its image acquisition construction. The tool needs to be placed on a turn-table and rotated, so that a single tooth is centered in the field-of-view of the camera mounted on a robot arm. For this alignment task, three different main approaches with various preprocessing steps are investigated, a brute-force algorithm, an orb-feature approach and an image regression model. The results show that even a brute-force algorithm can be outperformed by a moderate deep neural network.

Research on simplification of face gear tooth surface design

Research on simplification of face gear tooth surface design

Research on the deformation characteristics of small module tooth during current-assisted splitting spinning of small module tooth-shaped part

Aiming at the problems such as low material utilization, poor strength and toughness of workpiece during manufacturing of small module tooth-shaped parts (SMTSPs) by traditional gear hobbing and shaping method, a current-assisted splitting spinning forming (CASSF) method was proposed to form SMTSPs with high performance requirements. A coupled electrical-thermal-mechanical finite element (FE) model was established based on the ABAQUS software, and the distribution of equivalent stress and equivalent strain, and deformation characteristics of small module tooth were investigated. The results show that the equivalent stress and equivalent strain decrease from tooth groove arc to the tooth crest arc and centre of the tooth groove at tooth profile surface. The distribution of equivalent stress and equivalent strain in the internal deformation region follows the same trend as the tooth profile surface from the centre of the tooth groove to the tooth groove arc, but increases from the tooth groove arc to the tooth crest. The material of small module tooth experiences three-directional stress state. The material in the gear tooth undergoes radial and axial elongation, and tangential compression, while in the tooth groove it undergoes radial compression, tangential and axial elongation.

Hardening of gear teeth depending on the concentration of abrasive particles in the transmission oil

The article deals with the issues of determining the life and limiting concentration of abrasive particles in the oil of transmission units, depending on the type of hardening of gear teeth. Resource was determined after volume hardening, hardening by current of high frequency and cementation by hardness of gears materials, on the friction machine on the samples which have been made of gears material, working in oil with abrasive particles, considering coefficient of acceleration at test. Maximum allowable concentration of abrasive particles in machine oil, were estimated on the basis of expression for calculation of wear rate, providing the set life, maximum allowable wear depending on modulus of gearing, hardness of gearing material, size of abrasive particles, geometrical and kinematic parameters of gearing.

Gear Tooth Fault Detection in Servo Motor Transmission Chain Using the Built-In Encoder of Servo Motors

Gear Tooth Fault Detection in Servo Motor Transmission Chain Using the Built-In Encoder of Servo Motors

Analysis of arbitrary tooth profiles of cylindrical gears using normal polar coordinates (Application to the generation of a gear tooth profile by a given tooth profile of rack cutter and its interference problem)

Analysis of arbitrary tooth profiles of cylindrical gears using normal polar coordinates (Application to the generation of a gear tooth profile by a given tooth profile of rack cutter and its interference problem)

Viabilidade do concreto permeável como material delineado como sistema de detenção para áreas de segurança de pistas de aeroportos

Abstract From the late 1960’s airport engineers developed special paving material for arresting aircraft gears in event of overrun as a partial extension of a runway end safety area. Such pavement surface material, inverting a general concept, should be crushed over the first pass of gear wheels resulting the aircraft to sink and being promptly arrested resulting in abrupt loss of velocity, preferability avoiding loss of lives and injuries as well as with minimum risks for the airplane structural integrity. Herein is analyzed and discussed the possible application of pervious concrete for such a task by simulating an actual situation (Congonhas airport) and understanding the structural effects on the crushable concrete surface layer, pointing out stresses, deflections and required strengths for the material. Simulations regarded the critical aircraft A 320-200 as well as fire-fighters cars over the pavements. Analysis complied to Federal Aviation Administration requirements for non-standard pavement structures as well simulation of stresses trough the finite element method for medium-thickened plates. Compressive stresses along with flexural excessive stresses, besides predictable punching shear stresses allowed to conclude by the feasibility of using low strength pervious concrete as alternative for engineered material to be built as arresting system.

Calculation of dynamic characteristics of elastic self-aligning gear wheel of the locomotive

The article presents the procedure for calculating the dynamic characteristics of the elastic self-aligning gear of the locomotive. The authors have developed a numerical-analytical method for dynamic calculation strength of the elastic self-aligning gear of the locomotive, an algorithm and a program for the MATHCAD 15 programming environment were developed.

Features of the Choice of Knurl Material for Cold Calibration of Cylindrical Mid-Module Gear Wheels

Features of the Choice of Knurl Material for Cold Calibration of Cylindrical Mid-Module Gear Wheels

Dynamics model and vibrational response analysis of helical gear-rotor-bearing transmission system

As a core component of wind turbines, wind power gear speed increasers often work in harsh environments, so it is necessary to study the vibration characteristics of gear transmission systems. Taking a wind turbine gearbox high-speed stage helical gear transmission system as the research object, the dynamics model of multi-degree-of-freedom helical gear-rotor-bearing transmission system is established by the lumped parameter method and solved by Runge-Kutta method, taking into account the tooth side clearance of the gear, transmission error, eccentricity and support force of the nonlinear bearing. The effects of input torque, transmission error and tooth side clearance on the vibration characteristic response of the helical gear train were analyzed. The relationship between the trend of amplitude change in each direction of the gear and the trend of change in the major frequency components was analyzed under the conditions of changing internal and external excitation. The results show that torsional vibration dominates in the system. As the input torque increases, the vibration amplitude of the driving and driven gears decreases, and the frequency amplitude decreases significantly at multiple locations. Gear transmission errors and changes in tooth side clearance have significant effects on gear vibration amplitudes, but are sensitive only to the meshing frequency. The trend of gear vibration amplitude caused by the change of external excitation of the gear set is synchronized with the trend of main frequency amplitude in the corresponding direction, while the change of vibration amplitude caused by internal excitation is consistent with the trend of mesh frequency amplitude in the corresponding direction. The results of this paper can pave a certain foundation for the design and fault diagnosis of wind power gearbox transmission system.

Mathematic modeling of vibration transmission path with discontinuous contact interfaces for gear dynamics in the gear-shaft-bearing-housing system

A twelve-DOF model of gear-shaft-bearing-housing system is developed to study the vibration transmission path characteristics under different internal excitations considering effect of discontinuous contact interfaces. Gear meshing generates vibrations to propagate through the transmission path consisting of gear, shaft, bearing, housing and multiple contact interfaces to reach the external transducer. Effect of contact interfaces between different transmitting components, including that between gear and shaft, inner race and outer race, outer race and housing are characterized using parallel contact stiffness and damping elements. Dynamic responses of transmitting components are analyzed for three internal excitations of single frequency sinusoidal force, dynamic meshing force of both normal and spalled gear tooth. An explicit mathematic model of transmission path function is constructed, which considers effect of transmission path on both amplitude attenuation and frequency structure shift for gear with/without fault. The transmission path function is verified with model predictions, finite element simulation and experiments.

Static transmission error measurement of various gear-shaft systems by finite element analysis

Transmission error (TE) is a significant parameter related to gears vibration widely investigated by many authors using different approaches. However, in previous studies, spur and helical gears were mainly examined. There is a lack of studies addressed to double helical and herringbone gears and a comparison among several types of gearing with parallel axes. In this paper, spur, helical, double helical, and herringbone gears are analyzed in terms of static transmission error (STE), contact pressure and tooth root stress. Static contact analyses were conducted using the finite element method (FEM) which is often considered a tool for validating other methods and approaches. Moreover, three variants of boundary conditions of each gear type are introduced, including flexible shafts and the effect of a tip relief modification at sole gears, without shafts, was analyzed. In addition, a concept of a compact test rig intended for STE measurements at low loads was presented. The results have shown, among other things, significant influence of the shaft stiffness and boundary conditions on meshing characteristics.

Model of the turboprop engine reduction gear tooth harmonic spectral component

The width of spectral components in rotary machines is determined by the frequency modulation of the carrier from the rotor speed deviation in the stationary operation mode. It was shown that, for the tooth spectral component, it is not enough to take into account this factor only. The analysis of publications and the studies performed show that it is also determined by the effect of many other factors: process-related ones (errors in manufacturing and assembly of gear wheels), operation mode parameters (rpm, temperature, transmitted load); design-related factors (flexibility of drive parts; modification of the tooth face), as well as uneven wear of tooth flanks. Using the planetary gearbox of a turboprop engine as an example, the structure of the tooth spectral component width in function of the analyzed influencing factors was considered. Based on the vibration statistics for eighteen gearboxes in overhauled engines, the choice of a ratio for the spectral component width of a frequency modulated process was justified. This choice showed readings closest to the corresponding experimental data. For the vibration of ten gearboxes with different degrees of tooth flank wear, the corresponding dependence of the width on the wear is presented. A mathematical model for the tooth spectral component width in overhauled and newly manufactured gearboxes as the product of the constant coefficient with the deviation dispersion sum from the considered factors was proposed. The same dependence was also given for gearboxes with wear when adding the dispersion from wear to the dispersion sum. It was demonstrated that, for the presented case of the maximum wear, its fraction in the total width was about 50%, whereas the fraction of the frequency modulation from the operating system of adjusting relative rotor speed constancy in the stationary engine operation mode was equal to half of all the other factors.

ОЦЕНКА ЭНЕРГЕТИЧЕСКИХ ПОКАЗАТЕЛЕЙ УСОВЕРШЕНСТВОВАННОГО ПРИВОДА МНОГООПОРНЫХ ДОЖДЕВАЛЬНЫХ МАШИН, ТИПА «КУБАНЬ-ЛК1»

The issues of assessing the energy performance of the improved drive of a multi-support irrigation machine (DM) operating in motion in the Kuban-LK1 circle are described. It is noted that in order to increase the efficiency of DM cart drives and increase the speed of their movement, it is necessary to develop geared motors with a high gear ratio. The most promising option seems to be the use of energy-intensive gearmotors equipped with wave transmission. The rationale for the use of highly efficient gearing is given through theoretical studies. It is indicated that today, in the design of machines of this type, wheel gears with ineffective worm gears are used, as a result of which a blocked connection and uneven peripheral wheel speeds are formed in the transmission of running systems, which leads to a decrease in efficiency. operation of gear motors. It is possible to eliminate such negative qualities of the operation of the Kuban-LK DM by equipping it with gearmotors with wave transmission. Experimental studies of the machine were carried out at Ozery JSC, Kolomensky district, Moscow region, on a prototype of an 8-bogie electrified multi-support DM “Kuban-LK1”. On four trolleys (No. 2, No. 3, No. 7 and No. 8), gear motors with wave transmission were installed on each wheel. Potatoes were watered. Agricultural background is a field planted with potatoes. The slope of the field along the water supply pipeline and in the direction of movement of the carts did not exceed ± 0.01. As a result of the research, operational indicators were obtained, presented in Table 1, which allowed us to draw the following conclusions: power consumption of the support trolley with a modernized drive when operating; two electric motors, is 300 - 370 W. Under the same conditions, a serial drive consumes 630 – 670 W. Thus, power savings occur due to increased efficiency. drive (η) from 0.5 to 0.8 and its unlocking, on average, by approximately 1.8 times.