Gear Transmission Density Maximization

2011 ◽  
Author(s):  
Alexander L. Kapelevich ◽  
Viacheslav M. Ananiev
Keyword(s):  
Gear Tooth ◽  
Load Capacity ◽  
Gear Ratio ◽  
Gear Transmission ◽  
Gear Trains ◽  
Reduced Costs ◽  
Gear Drives ◽  
Internal Gear ◽  
Ratio Optimization ◽  
Volume Functions

Maximization of the gear transmission density presents an important task. It allows to increase the output torque within given dimensional constrains that is critical, for instance, in racing gearboxes, or to reduce size and weight of aerospace gear drives. It can also lead to reduced costs for automotive and consumer product gear trains, etc. There are several ways to increase gear drive load capacity, including advanced design, materials, and technologies. This paper presents an approach that allows optimizing gearbox kinematic arrangement and gear tooth geometry to achieve high gear transmission density. It introduces dimensionless gearbox volume functions, which can be minimized by the internal gear ratio optimization. Different gearbox arrangements are analyzed to define a minimum of the volume functions. Application of the asymmetric gear tooth profiles power density maximization is also considered.

Improved Genetic Optimization of Electric Motorcycle Planetary Transmission

2012 ◽  
Vol 246-247 ◽  
pp. 164-168
Author(s):  
Pei Lin Yu ◽  
Wang Yong
Keyword(s):  
Planetary Gear ◽  
Optimization Method ◽  
Gray Code ◽  
Gear Transmission ◽  
Design Parameters ◽  
Preliminary Design ◽  
Genetic Optimization ◽  
Gear Trains ◽  
Planetary Transmission ◽  
Gear Drives

Determination of dedendum circle diameter of ring gear in planetary gear drives is an important issue in preliminary design of electric motorcycle transmission. Genetic optimization is used to automate preliminary design of gears by minimizing volume of gear trains. An improved genetic optimization method was applied to a planetary gear transmission of electric motorcycle. Gray code way was applied in variable binary strings for improve research efficiency. Dynamic penalty functions were introduced to the objective function for handing the design constraints. The results were compared with a enumeration method usually applied. Improved GA produced quite well results promptly supplying design parameters of a planetary gear transmission.

Determination of Addendum Modification Coefficients for Spur Gears Operating at Non-Standard Center Distances

2003 ◽  
Author(s):  
M. A. Sahir Arikan
Keyword(s):  
Gear Tooth ◽  
Gear Ratio ◽  
Spur Gears ◽  
Contact Ratio ◽  
Performance Variables ◽  
Practical Design ◽  
Gear Drives ◽  
Maximum Contact ◽  
Center Distance

Although it is possible to find some recommended conventional values both for the sum of the addendum modification coefficients and for the allocation of the sum of the addendum modification coefficients (e.g. ISO/TR 4467), a detailed analysis is necessary to determine the addendum modification coefficient values for the desired optimization criteria and the performance since the main objective of the above mentioned sources is to facilitate practical design of non-standard gear drives which will not have problems while operating. They give practical average values within a safe range. In this study, by considering the required gear ratio, center distance and the desired backlash, alternative gear pairs are determined and corresponding gear performance variables are calculated in order to allocate the addendum modification coefficients for the pinion and the gear by using criteria such as: not having undercut or pointed (or excessively-thinned-tip) tooth, having desired proportions for the lengths of the dedendum and addendum portions of the line of action, having maximum contact ratio, having sufficient bottom clearance, having minimum contact stresses, having balanced pinion and gear tooth root stresses, having equal pinion and gear lives, etc.

scholarly journals Design of Electrically Powered Morphing Winglet

2021 ◽  
Author(s):  
Kunj Mistry
Keyword(s):  
Material Selection ◽  
Gear Tooth ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Stepper Motor ◽  
Spur Gears ◽  
Input Shaft ◽  
Gear Drive ◽  
Electrical Actuator ◽  
Gear Drives

Cycloidal and planetary gear drives are considered for the actuation of an electrically powered morphing winglet. A torque of 6723 N*m is required at the winglet hinge. The stepper motor selected as the electrical actuator is the HT34-487 stepper motor. This motor can provide a torque of approximately 6 N*m. The cycloidal drive consists of the selected stepper motor, a bevel gearbox, and a two-stage cycloidal gearbox. The bevel gearbox is used to change the axis of rotation of the stepper motor from span-wise direction to chord-wise direction. Stage one of the cycloidal gearbox contains an input shaft, two cycloidal disks with 180 degrees offset rotation, an eccentric cam and an output shaft. The cycloidal disks in stage one have 35 lobes, providing a gear ratio of 35:1. The second stage of the cycloidal gearbox consists of only one cycloidal disk with 34 lobes, providing a gear ratio of 34:1. The total gear ratio of the cycloidal drive is 1190:1. Material selection and FEA simulations are performed on the components in the cycloidal drive to ensure the selected materials can withstand the applied loads. A differential planetary gear drive is also considered to actuate an electrically powered morphing winglet. Spur gears are selected to be used as the sun and planet gears. A ratio of 180:1 is achieved in the planetary gear drive. Using gear tooth bending calculators, it is found that designing spur gears to withstand the loads of the electrically powered morphing winglet and to fit inside the dimensions of the wingbox is not feasible.

scholarly journals The Influence of the Bearing Lifetime on the Performance of Universal Gear Drives with High Gear Ratio Values

2019 ◽  
Vol 287 ◽  
pp. 01022
Author(s):  
Milan Rackov ◽  
Siniša Kuzmanović ◽  
Ivan Knežević ◽  
Maja Čavić ◽  
Marko Penčić ◽  
...  
Keyword(s):  
Load Capacity ◽  
Gear Ratio ◽  
Output Shaft ◽  
Operating Life ◽  
Gear Drive ◽  
High Speeds ◽  
Low Speeds ◽  
Gear Drives

The problem of defining the load (nominal torque on the output shaft - T2N) of universal gear drives depending on the size of the gear ratio is analysed in this paper. It is logical that the load capacity of gear drive depends on the weakest gear component. Since the gears are the most expensive components of gear unit, it tends to maximize their performance. However, for low gear ratio, i.e. for high speeds, the bearings often limit their load capacity since the same bearings are used in all transmission ratios because it is not practiced to oversize the bearings at low speeds. Nowadays, when high values of gear ratio are used, it is interesting to consider the dependence of the nominal torque at the output regarding to gear ratio and operating life of the unit.

scholarly journals Design of Electrically Powered Morphing Winglet

2021 ◽  
Author(s):  
Kunj Mistry
Keyword(s):  
Material Selection ◽  
Gear Tooth ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Stepper Motor ◽  
Spur Gears ◽  
Input Shaft ◽  
Gear Drive ◽  
Electrical Actuator ◽  
Gear Drives

Cycloidal and planetary gear drives are considered for the actuation of an electrically powered morphing winglet. A torque of 6723 N*m is required at the winglet hinge. The stepper motor selected as the electrical actuator is the HT34-487 stepper motor. This motor can provide a torque of approximately 6 N*m. The cycloidal drive consists of the selected stepper motor, a bevel gearbox, and a two-stage cycloidal gearbox. The bevel gearbox is used to change the axis of rotation of the stepper motor from span-wise direction to chord-wise direction. Stage one of the cycloidal gearbox contains an input shaft, two cycloidal disks with 180 degrees offset rotation, an eccentric cam and an output shaft. The cycloidal disks in stage one have 35 lobes, providing a gear ratio of 35:1. The second stage of the cycloidal gearbox consists of only one cycloidal disk with 34 lobes, providing a gear ratio of 34:1. The total gear ratio of the cycloidal drive is 1190:1. Material selection and FEA simulations are performed on the components in the cycloidal drive to ensure the selected materials can withstand the applied loads. A differential planetary gear drive is also considered to actuate an electrically powered morphing winglet. Spur gears are selected to be used as the sun and planet gears. A ratio of 180:1 is achieved in the planetary gear drive. Using gear tooth bending calculators, it is found that designing spur gears to withstand the loads of the electrically powered morphing winglet and to fit inside the dimensions of the wingbox is not feasible.

Analysis on the Selection of Tooth Number for Closed Differential Planetary Gear Transmission Mechanism and Software Development

2014 ◽  
Vol 670-671 ◽  
pp. 809-813
Author(s):  
Jin Feng Sun ◽  
Hai Feng Zhu ◽  
Jun Wang ◽  
Quan Wang
Keyword(s):  
Design Method ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Gear Transmission ◽  
Transmission Mechanism ◽  
Theoretical Research ◽  
Ratio Condition ◽  
Tooth Number ◽  
Gear Trains ◽  
Selection Of

With the popularization of computer, the design of planetary gear trains is headed in the automatic direction. Based on the theoretical research of closed differential planetary gear transmission mechanism, a kind of software was developed to automatically calculate the tooth number with computer technology applied to the design of gear trains. Some research and analysis were done to the transmission mode of closed differential planetary gear transmission mechanism with the help of universal design method on gear trains. Five constraint conditions were summarized, which are gear ratio condition, adjacency condition, assembly condition, concentricity condition, and other conditions, and a optimum condition. With windows 7 as the platform, MyEclipse 8.5 as a tool, translating these conditional formulae into Java language, the software of the selection of tooth number for closed differential planetary gear transmission mechanism was developed. Multi-group datum of tooth number and also a set of optimal data can be obtained after running the software, which reduces the workload of manual calculation.

Probabilistic Analysis of MEMS Asymmetric Gear Tooth

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Fatih Karpat ◽  
Stephen Ekwaro-Osire ◽  
Morshed P. H. Khandaker
Keyword(s):  
Gear Tooth ◽  
Load Capacity ◽  
Probability Of Failure ◽  
Mems Devices ◽  
Contact Ratio ◽  
Microelectromechanical System ◽  
Gear Teeth ◽  
Failure Theory ◽  
Gear Drives ◽  
Root Stress

Currently, there is an increased interest in the application of microelectromechanical system (MEMS) gear drives. Additionally, requirements for transmitted power and related reliability issues have increased. Reliability issues often occur due to uncertainties of material, geometry, and loading conditions of the MEMS gears. Asymmetric gear teeth are used to improve the performance of gears by increasing the load capacity or by reducing vibrations. In this paper, asymmetric gear teeth are proposed for MEMS applications. The objective of this research is to investigate the feasibility of applying asymmetric gears for MEMS devices while accounting for uncertainty. The Weibull failure theory was applied to four different MEMS gear configurations. The following analyses were carried out in this research: (i) for the calculation of root stress, four different asymmetric gears were used; (ii) for the calculation of the probability of failure, the Weibull failure theory formulization was used, and (iii) the efficacy of the various asymmetric tooth configurations was discussed. Specifically, the probability of failure of the asymmetric gear was extracted for various parameters. The parameters considered included pressure angle, tooth height, and contact ratio. The efficacy of using asymmetric gear teeth was shown in this study.

The Generation Principle and Mathematical Models of Double-Enveloping Internal Gear Pairs

2015 ◽  
Author(s):  
Xuan Li ◽  
Bingkui Chen ◽  
Yawen Wang ◽  
Guohua Sun ◽  
Teik C. Lim
Keyword(s):  
Mathematical Model ◽  
Load Capacity ◽  
Geometrical Shape ◽  
Gear Pair ◽  
Numerical Examples ◽  
Proposed Model ◽  
General Mathematical Model ◽  
Meshing Characteristics ◽  
Internal Gear ◽  
Tooth Pair

In this paper, the planar double-enveloping method is presented for the generation of tooth profiles of the internal gear pair for various applications, such as gerotors and gear reducers. The main characteristic of this method is the existence of double contact between one tooth pair such that the sealing property, the load capacity and the transmission precision can be significantly improved as compared to the conventional configuration by the single-enveloping theory. Firstly, the generation principle of the planar double-enveloping method is introduced. Based on the coordinate transformation and the envelope theory, the general mathematical model of the double-enveloping internal gear pair is presented. By using this model, users can directly design different geometrical shape profiles to obtain a double-enveloping internal gear pair with better meshing characteristics. Secondly, to validate the effectiveness of the proposed model, specific mathematical formulations of three double-enveloping internal gear pairs which apply circular, parabolic and elliptical curves as the generating curves are given. The equations of tooth profiles and meshing are derived and the composition of tooth profiles is analyzed. Finally, numerical examples are provided for an illustration.

Investigation of Noise Features of Planetary Gear Trains Based on Human Aural Characteristic

2017 ◽  
Author(s):  
Masao Nakagawa ◽  
Dai Nishida ◽  
Deepak Sah ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama
Keyword(s):  
Gear Tooth ◽  
Structural Complexity ◽  
Planetary Gear ◽  
Transmission Error ◽  
Sound Level ◽  
Tooth Surface ◽  
Surface Error ◽  
Planetary Gear Trains ◽  
Tooth Stiffness ◽  
Gear Trains

Planetary gear trains (PGTs) are widely used in various machines owing to their many advantages. However, they suffer from problems of noise and vibration due to the structural complexity and giving rise to substantial noise, vibration, and harshness with respect to both structures and human users. In this report, the sound level from PGTs is measured in an anechoic chamber based on human aural characteristic, and basic features of sound are investigated. Gear noise is generated by the vibration force due to varying gear tooth stiffness and the vibration force due to tooth surface error, or transmission error (TE). Dynamic TE is considered to be increased because of internal and external meshing. The vibration force due to tooth surface error can be ignored owing to almost perfect tooth surface. A vibration force due to varying tooth stiffness could be a major factor.

Calculation of Cylindrical Worm Gear Drives of Different Tooth Profiles

1981 ◽  
Vol 103 (1) ◽  
pp. 73-82 ◽  
Author(s):  
H. Winter ◽  
H. Wilkesmann
Keyword(s):  
Coefficient Of Friction ◽  
Theoretical Basis ◽  
Power Loss ◽  
Influence Factor ◽  
Load Capacity ◽  
Worm Gear ◽  
Important Influence ◽  
Test Results ◽  
The Coefficient Of Friction ◽  
Gear Drives

The formulae of classical hydrodynamics are not suitable for the calculation of load capacity and power loss of worm gear drives. Thus a theoretical basis had to be developed for the comparison of different tooth profiles, materials of worm and worm wheel and lubricants. The data obtained were compared with test results. It proved that the coefficient of friction is an important influence factor.

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