Gear Parameters Research Articles

Design and Fatigue Analysis of an E-Drive Transmission System of Single-Speed Gear for Electric Vehicle

Design an e-drive transmi ssion gear , it is very crucial, to understand the failure modes since gears should be sized correctly to withstand loads that will expect to act on the gear teeth and make sure that still be within reasonable load-carrying capacity, compact and light weight. Fatigue failure can happen on gears under repeated loading due to fatigue such as tooth root bend ing and contact stress of gear. M aterials used in this study were two candidate alloy steels of Cr-Mo and Cr-Mo-Ni and methods employed to design the e-drive transmission gear were by iteration through KISSsoft gear simulation software as well as AGMA of Matlab script, it approaches various parameters such as helix angle, face- width , and input torque . Investigations on safety factors of root bending and contact , stresses of contact and bending , weight, compactness, qui e t and smooth functioning have been done by altering the variable design parameters . To conclude that by increasing face width and helix angle both safety factors were increased uniformly regardless of the in put torque as we calculated by both approaches. Similarly , the results showed that by increasing the helix angle and face width it brings to reduce the contact and bending stress es of transmission gear . As we comparing the results , the KISSsoft values are a little higher than the analytical (AGMA) values as proven in all fatigue of safety factors versus variable gear design parameter. Based on the sa fety factor, compactness, light weight and quiet for smooth function of the designed e-drive mating gears are proven as the face width is 24.5 mm and the helix angle is 25 o .

Loading of satellite bearing of planetary cycloid gear by forces acting in meshing

The main feature of planetary cycloid gears is the multi-pair contact of the pin-rollers and teeth of the cycloidal disk. To establish liaisons in the gear, mathematical models of the satellite’s force interaction with pin-rollers are used. The dependences of the total forces in meshing, which occur under the action of a torque applied to the output shaft, from the gear parameters, clearances in gear and the relative position of gear elements are given. The results of calculations performed in Mathcad using the proposed model show how the forces change in the direction of the inter-axis line of gear with increasing clearances at a constant torque on the output shaft. This solution allows estimating the forces acting on the satellite bearings at the specified manufacturing accuracy at the design stage of the gear.

Complex design of multi-machine electromechanical system of wind generators


 
 
 The direction of modernization of the wind power plant is substantiated, which is aimed at a comprehensive increase in energy efficiency and resource conservation. Taking into account the reasons for the destruction of the teeth of the gear, a constructive scheme of a single-stage gearbox with several output shafts is proposed. This scheme allows you to distribute the output power to several electric machines, which, in turn, reduces the mechanical stress in the area of contact of the teeth of the gears and gears of the output shafts. Due to the division of the output power into several machines, the mass and dimensions of the gearbox are also reduced. The uniformity of power distribution on the shafts can be violated by the discrepancy between the parameters of gears, electromagnetic and mechanical parameters of electric machines. In the proposed design scheme, the uniformity of energy flows along the shafts is ensured by a sequential connection of the phases of the stator windings of electric generators.
 
 

A method for selecting parameters of the electromechanical transmission of an industrial tractor

The article describes a method for selecting the torque — speed characteristics of the drive motors and parameters of the electromechanical transmission of an industrial tractor. In order to provide the maximum performance of the tractor the transmission developed in the research has two gears:transportation range and technological range. The distinctive feature of the transmission is the use ofthe ZK tank steering systemdeveloped by the researchers of BMSTU (G.I. Zaychik, M.A. Kreynes, M.K. Kristi).The authors have studied the impact ofthe design parameter of the planetary gear sets of the ZK mechanism on the tractor performance. The torques and drive motor rotor speeds providing required performance in a turn as a functions of the planetary gear design parameter have been calculated. Also the time of the tractor full turn around its center of mass and around one braked track when the transmission operates in the transport and technological ranges has been found. An finaly, the impact of the tractor transmission parameters on the maximum tractor speed at manoeuvring has been analysed. The results of the analysis were used for selection of the electric motor output power providing a comfortable work for the tractor operator.

Simulation analysis of the tooth modification about wind power gearbox based on Romax software

At present, the gearboxes are faced with the problems of high failure rate, large vibration and noise, short service life etc. Gear modification is an effective means to reduce vibration and noise, extend life, which has been proved by practical experience at home and abroad for many years. With the introduction of some professional gear software or wind turbine analysis software from abroad, the work efficiency has been improved greatly and the extra cost due to experimental verification has also been reduced. With the use of Romax WIND excellent load distribution analysis function on the basis of the theory of gear modification, the static simulation analysis of the gearbox through the Romax WIND software was carried out under the equivalent loads. According to the load distribution on the tooth surface of gear, transmission errors and other parameters, the length, amount and curve of axial modification and the tooth profile of the high-speed pinion gear were analyzed and determined in the end. Conclusions can provide reference for gear modification.

A Detailed Investigation of Gear Body-Induced Tooth Deflections and Development of an Improved Analytical Solution

Many researchers have developed analytical methods to evaluate gear meshing stiffness. Some of these methods ignored the effect of the gear body while others used a simplified model to consider its effect. Until now, a detailed investigation of gear body-induced tooth deflections has been rare, especially for the double-tooth-pair meshing period. In this study, we present a detailed investigation of gear body-induced tooth deflections. To be specific, we will discuss how to accurately evaluate gear body-induced tooth deflections using the finite element analysis, and what are the effect of parameters such as loading and gear parameters on gear body-induced tooth deflections. Then, an improved solution is developed for evaluating the body-induced tooth deflection. In the single-tooth-pair meshing period, the improved formula is developed based on a popular formula proposed by Sainsot and Velex. This is achieved by optimizing the coefficients used in their formula to make the formula more accurate to evaluate gear body-induced tooth deflections. Meanwhile, we introduce a new term called affiliated body stiffness to evaluate the body-induced tooth deflections in the double-tooth-pair meshing period. The improved method can give higher accuracy in evaluating gear body-induced tooth deflections of spur gears with a pressure angle of 20°.

A validation procedure to identify joint friction, reductor self-locking and gear backlash parameters

The paper presents a new method for the identification of joint friction, reductor self-locking and gear backlash parameters. The method was developed using an existing hexapod robot. During the process, the motor driving currents given by the model and measured on the real device were observed and compared. Initially, the current curves showed specific differences. After the analysis of these deviations, their causes were identified as joint friction, reductor self-locking and gear backlash. The parameters of these phenomena were determined using swarm optimization. As a result of this process, a validated model was obtained. The mentioned mechanical properties were identified using a step-by-step method, in which one property aided in the discovery of another. The robot model was created in a MATLAB/Simulink environment, using the Simscape Multibody Toolbox.

An increase of the loading capacity and reliability of gears by methods of optimizing involute gearing parameters

A large volume of rocks containing valuable minerals is treated at mining and processing plants in Kazakhstan. Ball mills and rod mills are used for their grinding and further processing in Balkhash, Zhezkazgan. Ball mills with gear drive rings in the drums suffer from intense wear of the teeth due to the heavy mode of the mill operation. It thus necessitates their frequent replacement and long mill downtime. The gears of the ball mill drive experience an intense impact stress, which reduces the resource of their operation and the mill as a whole due to wear. The article presents research on developing rational parameters of involute gearing, aimed at increasing the loading capacity of the gear as well as reducing the overall dimensions, noise, and vibration. In order to solve the set tasks, dynamic processes are simulated, modification of the teeth is proposed, and the task of designing the initial meshing contour is solved when the line of the tooth profile is slightly deviated from the involute curve of the tooth surface. The kinematic and dynamic parameters of a tooth transmission influencing the wear resistance of teeth are found out, and also the influence of the loading capacity under conditions of stable lubrication is determined. Because of the complexity of modifying a large diameter of the driven gear wheel, it is proposed to modify only the teeth of the driving wheel, both at their tops and legs

Mathematical model and tooth contact analysis of convexo-concave helical bevel Novikov gear mesh

This paper presents a mathematical model of convexo-concave helical bevel Novikov gear mesh. The usefulness of the designed mathematical model for tooth contact analysis was demonstrated. Moreover, a number of simulations were carried out aiming at evaluation of the influence of gear position errors as well as gear parameters on contact pattern and transmission error. Obtained results were compared with a conventional spiral bevel gear pair generated by duplex helical method. For the example provided, the Novikov one was shown to have greater instantaneous contact area and therefore reduced contact stress value.

"Analytic description of teeth profile of gears with rollers ab and justification of precessional gear parameters selection a"

The engineering complex study of the triad “gear-technology-transmission” has permitted to elaborate a new type of mechanical transmission – planetary precessional transmissions with multicouple gear. In this paper, the authors present the mathematic model of the multicouple gear. A computer program for doing this it is also elaborated. It is shown the calculus modalities and some teeth profile diagrams.

Model-based transmission acoustic analysis and improvement

A model-based transmission acoustic performance has been studied. Both excitation source and structure-borne noise transfer are investigated. For excitation source, transmission error is the main cause. To reduce transmission error, the most effective method is gear micro-geometry modification. However, there is no direct mathematical model that could reveal the relationship between transmission error and gear micro-geometry parameters, especially in the context of transmission system with shafts, bearings and housings included. By using multiple variable linear regression method, the relationship between transmission error and gear micro-geometry parameters is connected. The optimised transmission error decreases from 9.34 to 5.65 μm at a typical working condition. For structure-borne noise transfer, the housing modal and transmission system modal have been analysed. Based on the simulation results, housing thickness around bearing assembly area is increased, and strengthen ribs are added at weak areas. As a result, the amplitude of housing vibration acceleration is reduced. Finally, the transmission noise sound pressure level at 0.3-m distance has decreased by 4.63 dB on average. The presented model-based transmission acoustic analysis work flow is demonstrated workable and effective.

Microstress cycle and contact fatigue of spiral bevel gears by rolling-sliding of asperity contact

The rolling contact fatigue (RCF) model is commonly used to predict the contact fatigue life when the sliding is insignificant in contact surfaces. However, many studies reveal that the sliding, compared to the rolling state, can lead to a considerable reduction of the fatigue life and an excessive increase of the pitting area, which result from the microscopic stress cycle growth caused by the sliding of the asperity contact. This suggests that fatigue life in the rolling-sliding condition can be overestimated based only on the RCF model. The rubbing surfaces of spiral bevel gears are subject to typical rolling-sliding motion. This paper aims to study the mechanism of the micro stress cycle along the meshing path and provide a reasonable method for predicting the fatigue life in spiral bevel gears. The microscopic stress cycle equation is derived with the consideration of gear meshing parameters. The combination of the RCF model and asperity stress cycle is developed to calculate the fatigue life in spiral bevel gears. We find that the contact fatigue life decreases significantly compared with that obtained from the RCF model. There is strong evidence that the microscopic stress cycle is remarkably increased by the rolling-sliding motion of the asperity contact, which is consistent with the experimental data in previous literature. In addition, the fatigue life under different assembling misalignments are investigated and the results demonstrate the important role of misalignments on fatigue life.

Optimal Design of Traction Gear Modification of High-Speed EMU Based on Radial Basis Function Neural Network

The dynamic characteristics of the traction gear transmission system have a great influence on the safety, comfort, and reliability of EMU (electric multiple units). Combining the methods of theoretical analysis, numerical simulation, and optimization design theory, establishing a parameterized gear modification model. Meanwhile, designing reasonable shape modification schemes and parameters. The dynamic characteristics, vibration response characteristics, and acoustic response characteristics of gear meshing of CRH380A high-speed EMU under continuous traction conditions are analyzed. The corresponding relationship between gear modification parameters and gear transmission radiation noise is approximated by finite element simulation data and RBF (radial basis function) neural network. Using a multi-island genetic algorithm to optimize gear modification parameters to minimize gear transmission noise, further seeking to meet the low-noise modification design of high-speed train traction helical gear transmission system under continuous operating conditions method.

Dynamics and strength of planetary gear with elements of increased flexibility at transient modes

The increased flexibility of links and details of planetary gear allows to reduce unevenness of load in gear meshing. On the other hand, the probability of emergence of vibrations increases. For the analysis of dynamics and strength of planetary gear during running-up the system of nine differential equations received earlier is used. For lowering of degree of a system a number of assumptions is accepted. The most part of deformations, in view of smallness, and the related elastic forces, are not considered. In the generalized forces the following power factors are left: torques of the engine and forces of useful resistance; elastic forces in axles of satellites. The system is reduced to two equations: vibrations of a satellite axle and rotation of a sun gearwheel. Dependences of natural frequencies of vibrations of satellite axle on gear parameters are received. It is considered the constant and variable torques of driving forces. Proceeding from satellite axle strength of bending, dependences between extreme value of the driving torque and rotary speed of a sun gearwheel and mass and dimensional characteristics of planetary gear are set.

Analysis of the geometry and contact density of globoid gearing

Globoid worm gears have been widely applied in a range of technological branches in which other types of worm gears are less effective. The main functional indicators which facilitated their popularity include high load capacity and durability, low vibroactivity and small energy losses. As the experience of application and the results of the study of globoid worm gears showed, the level of operational properties of globoid gears is higher than that of the others only if the gearing and technological parameters of their manufacturing are optimally chosen during the design stage. This paper describes a method for estimating the gearing parameters of a globoid gear with an account of the geometry of the elements (the geometry of the teeth of the wheel and the worm thread), namely the calculation of the gap fields in the globoid gearing by means of numerical methods.

Drivetrain modelling and parameter calculation for an electric bus with fixed or 2-speed gearbox

This paper presents drivetrain calculations for an electric bus. Parameters of motor, gears and motor efficiency map are used. The goal is to select the suitable motor and gearbox. Driving cycle SORT2 and real life driving cycles measured on bus lines are used. Based on the bus manufacturer assignment, only permanent magnet synchronous machines are considered. The motor output power is considered in the range of 120-160 kW. The selection of axle gear ratios was limited to 6.19, 6.5 and 7.35, as those are readily available. The gearbox was either a fixed one, with gear ratio of 1.8, or a 2-speed gearbox with a gear ratio of 1 and 1.8. The calculations have shown, that a 2-speed gearbox can decrease the energy consumption. The improvement is in the range of 1-3% dependent on the motor option and driving cycle.

Dynamic research of elementary differential gear with elastic links

Many research works are devoted for study of static and dynamic parameters of planetary gears of various designs. A number of dynamic problems can be solve accurately enough without taking into account the elasticity of loaded elements. In calculations of mining machines transmissions dynamic processes must be considered gear flexibility as is much more than flexibility of large diameter and small length shafts. In this article are considered possibilities and features of research of dynamic phenomena that take a place in planetary mechanisms of mining machine transmissions. For this purpose planetary mechanisms are presented as elastic mechanical systems. For research the dynamic model of elementary differential mechanism with taking into account the link elasticity is used. For this purpose the differential gear presented as equivalent planetary row with inertialess planetary carrier. Main links of such mechanism have inertia moments determined by known formulas. The equivalent dynamic model of elementary differential gear is presented as three-mass branched system. Moments of elasticity, occurring in mechanical constraints of system, are determined. Equations of movement for each of the masses give the linear homogeneous differential equation system or free oscillations equation system of mechanism. This system is representable as linear algebraic equation system. Particular solutions of inhomogeneous differential equation system are of practical interest, as they permit to make the analysis of the effect of external loads, acting on the mechanism. Operator solution method application will give particular solutions of linear inhomogeneous differential equations. Received systems will allow solving many dynamic tasks of elastic mechanical systems: character change and maximum values of mechanism links dynamic loads, periods and frequencies of oscillations, conditions of the resonant state of the mechanical system.

Adjusting of polar crane running gear at the corporate customer site

The article discusses the issues of adjustment of polar cranes at the customer site. It shows that the defining characteristics when adjusting the movement of the crane around the circumference are the geometric parameters of the running gear. It is noted that the repair-fit geometry of the bridge and the running gear of the crane corresponds to its non-stressed state. The non-stressed state of the crane characterizes the condition under which the deformations in its structural elements are absent or minimal. This crane position is achieved by installing it on the track in the middle between the two limiting states that are predetermined. It is emphasized that defects are eliminated exclusively in the running gear of the crane in the process of adjustment. Errors made in the process of manufacturing and installation are compensated during the crane adjustment. It is noted it refers to all errors made in the manufacture of structural elements as well as those made directly during their installation, and non-standard gaps in the moving parts of the crane determining their backlash.

Dynamics Modeling and Tension Control of Composites Winding System Based on ASMC

Tension is a key processing parameter in the process of composite fiber tape winding. The fluctuation of tension will affect the accuracy of winding and the performance of winding products, such as stress uniformity, fatigue resistance, strength, compactness and resin content. In view of the winding tension is time-varying and the application of tension needs to be more accurate, a tension calculation model is established. Due to the influence of dynamic performance of tension control system by cogging torque, inverter dead zone, ring gear clearance, friction torque, parameter drift, and measurement noise, an adaptive sliding mode control (ASMC) based on extended state observer (ESO) is proposed. The stability of the closed-loop system is proven by Lyapunov theory, the system state variables is estimated by ESO, and the input dead-zone is compensated by the designed adaptive law. Simulation and experimental results show that ESO-based ASMC improves the robustness and dynamic response performance of the tension control system, and can effectively suppress the chattering of the sliding mode control system. The void content and residual stress of composite products have been improved obviously.

Solving the problem of optimal design for a two-stage reducer by using a modified evolutionary algorithm

The work is devoted to solving the problem of selecting optimal geometric parameters of gears of a two-stage cylindrical reducer using a modified evolutionary algorithm (EA). The statement of the problem is considered, design parameters, objective functions, limitations on design parameters are determined. This allowed us to propose a modification of EA. To generate the initial test points, it was proposed to use the LP-τ sequence, this allowed us to reduce the initial population of test points and bring EA closer to a truly “random” process. The scheme of the proposed algorithm is considered, which gives an idea of the sequence of operations that are carried out with populations of test points at each stage of the evolutionary process. The solution of the specific problem of selecting optimal parameters for a serial reducer is given. The input data, numerical and functional limitations are determined, the objective functions are formed. The results of the solution are shown in several presentation formats: tabular and graphical, which allows to qualitatively interpret and analyze the results. Conclusions are made about testing the proposed algorithm for solving a specific problem of optimal design. Further ways of improving this methodology are proposed.