scholarly journals Genetic Approach for Multiobjective Optimization of Epicyclical Gear Train

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Kaoutar Daoudi ◽  
El Mosthapha Boudi ◽  
Mohsine Abdellah
Keyword(s):  
Multiobjective Optimization ◽  
High Efficiency ◽  
Bending Strength ◽  
Power Transmission ◽  
Planetary Gear ◽  
Operating Mode ◽  
Optimization Methods ◽  
Gear Train ◽  
Tooth Width ◽  
Power Transmission Systems

The determination of optimal design of the planetary gear train with a lightweight, a short center distance, and a high efficiency is an important issue in the preliminary design of power transmission systems. Conventional and traditional methods have been widely used in optimization. They are deterministic and limited to solve some mechanical problems with several variables and constraints. Therefore, some optimization methods have been developed, such as the nonconventional method, the genetic algorithm (GA). This paper describes a multiobjective optimization for the epicyclical gear train system using the GA. It is aimed to obtain the optimal dimensions for epicyclical gear components like a module, number of teeth, the tooth width, the shaft diameter of the gears, and a performed efficiency under the variation of operating mode of PGT system. The problem is formulated under the satisfaction of assembly and balance constraints, bending strength, contact strength of teeth, and other dimension conditions. The mathematical model and all steps of the GA are presented in detail.

scholarly journals Design and Analysis of a Novel Speed-Changing Wheel Hub with an Integrated Electric Motor for Electric Bicycles

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yi-Chang Wu ◽  
Zi-Heng Sun
Keyword(s):  
High Speed ◽  
Power Transmission ◽  
Permanent Magnet Synchronous Motor ◽  
Planetary Gear ◽  
Rear Wheel ◽  
Gear Train ◽  
Direct Drive ◽  
Element Analysis ◽  
Embodiment Design ◽  
Electric Bicycles

The aim of this paper is to present an innovative electromechanical device which integrates a brushless DC (BLDC) hub motor with a speed-changing wheel hub stored on the rear wheel of an electric bicycle. It combines a power source and a speed-changing mechanism to simultaneously provide functions of power generation and transmission for electric bicycles. As part of the proposed integrated device, the wheel hub consists of a basic planetary gear train providing three forward speeds including a low-speed gear, a direct drive, and a high-speed gear. Each gear is manually controlled by the shift control sleeve to selectively engage or disengage four pawl-and-ratchet clutches based on its clutching sequence table. The number of gear teeth of each gear element of the wheel hub is synthesized. The BLDC hub motor is an exterior-rotor-type permanent-magnet synchronous motor. Two-dimensional finite-element analysis (FEA) software is employed to facilitate the motor design and performance analysis. An analysis of the power transmission path at each gear is provided to verify the validity of the proposed design. The results of this work are beneficial to the embodiment, design, and development of novel electromechanical devices for the power and transmission systems of electric bicycles.

scholarly journals AHP Decision Making Algorithm for Development of HVDC and EHVAC in Developing Countries

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Ali Aranizadeh ◽  
Mehrzad Kazemi ◽  
Homayoun Barahmandpour ◽  
Hamidreza Ahady Dolatsara
Keyword(s):  
Decision Making ◽  
Developing Countries ◽  
Urban Areas ◽  
Power Transmission ◽  
Cost Effective ◽  
Optimization Methods ◽  
Final Decision ◽  
Transmission Systems ◽  
Power Transmission Systems ◽  
Bulk Power

Nowadays, as the population of urban areas increases, the need for consumption increases as well. This amount of consumption requires power generation centers with large volumes exploiting that it needs to be big enough, which guides technology towards bulk power transmission systems. In doing so, two types of power transmission systems, including HVDC and EHVAC, can be studied. However, since none of the above technologies has been used in developing countries, a decision should be made to introduce and develop any of these technologies. Applying both technologies together would not be cost-effective. A decision-making development needs the principles of conflicting purposes for alternatives and the selection of the best choice based on the needs of decision-makers. Multi-objective optimization methods may well provide a solution for this selection. Thus, this paper studies deciding on the introduction and Development of HVDC and EHVAC in a developing country, Iran. To this end, measures of this selection are described in detail, and then, AHP, one of the well-known MCDM method, is used to make the final decision.                                                                                                               

Recent Progress and Prospect on Tooth Modification of Involute Cylindrical Gear

2021 ◽  
Vol 14 ◽  
Author(s):  
Lin Han ◽  
Yang Qi
Keyword(s):  
Load Distribution ◽  
Power Transmission ◽  
Gear Tooth ◽  
Transmission Error ◽  
Gear Pair ◽  
Cylindrical Gear ◽  
Tooth Width ◽  
Modification Method ◽  
Power Transmission Systems ◽  
Tooth Modification

Background: Recent reviews on tooth modification of involute cylindrical gear are presented. Gear pairs are widely employed in motion and power transmission systems. Manufacturing and assembling errors of gear parts, time-varying mesh stiffness and transmission error of gear pair, usually induce vibration, noise, non-uniformly load distribution and stress concentration, resulting in earlier failure of gear. Tooth modification is regarded as one of the most popular ways to suppress vibration, reduce noise level, and improve load distribution of gear pairs. Objective: To provide an overview of recent research and patents on tooth modification method and technology. Methods: This article reviews related research and patents on tooth modification. The modification method, evaluation, optimization and machining technology are introduced. Results: Three types of modifications are compared and analyzed, and influences of each on both static and dynamic performances of gear pair are concluded. By summarizing a number of patents and research about tooth modification of cylindrical gears, the current and future development of research and patent are also discussed. Conclusion: Tooth modification is classified into tip or root relief along tooth profile, lead crown modification along tooth width and compound modification. Each could be applied in different ways. In view of design, optimization under given working condition to get optimal modification parameters is more practical. Machining technology and device for modified gear is a key to get high quality performance of geared transmission. More patents on tooth modification should be invented in future.

Selection and Design of Planetary Gear Trains Based on Power Flow Maps

2005 ◽  
Vol 127 (1) ◽  
pp. 120-134 ◽  
Author(s):  
David R. Salgado ◽  
J. M. Del Castillo
Keyword(s):  
Power Flow ◽  
High Efficiency ◽  
Functional Dependence ◽  
Planetary Gear ◽  
Gear Train ◽  
Transmission Ratio ◽  
Flow Maps ◽  
Family Of Curves ◽  
Power Maps ◽  
Flow Map

It is shown that for any planetary gear train (PGT) it is possible to find the relationship existing between the transmission ratio of the train and the power transmitted through each gear pair (gearing power). Specifically, for trains of five and six members, this functional dependence generates a family of curves parameterized by the transmission ratio. A plot of this family of curves is called a power flow map. It allows one to identify those trains that have a potentially high efficiency. In particular, it identifies the transmissions which present power recirculation, a condition that is generally undesirable. Also, an analysis of the power flow maps for the six-member trains leads to the conclusion that, for most of these trains, there is a single expression for the efficiency. The interest of the proposed method is that it is only necessary to know the expression for the PGT’s transmission ratio in order to obtain its power flow map. Also, the map is independent of the constructional solution that is adopted for the train. Finally, the power maps that are obtained are used to find alternatives to the designs of a train consisting of several stages of a basic four-member PGT.

Analysis System of Marine Planetary Gear Trains

2011 ◽  
Vol 86 ◽  
pp. 55-58 ◽  
Author(s):  
Geng Liu ◽  
Shan Chang ◽  
Li Yan Wu ◽  
Ying Sheng Li
Keyword(s):  
Dynamic Characteristics ◽  
Power Transmission ◽  
Planetary Gear ◽  
Gear Train ◽  
Static And Dynamic Characteristics ◽  
The Past ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
Analysis System ◽  
Herringbone Gear

Planetary gear train (PGT) with herringbone gears is one of typical transmission styles used in marine power transmission. How to effectively design a PGT with lighter structures and lower vibration and noise is a fatal task for heavily loaded marine gearing. An analysis system which was developed in the past decades is introduced in this paper to simulate the performance of planetary herringbone gear trains. The effects of main crucial parameters on the static and dynamic characteristics of planetary herringbone gear trains are studied by using the analysis system. The results are discussed and show that the presented system is effective and can be used in design of planetary herringbone gear trains.

The effect of planetary gear/star gear on the transmission efficiency of closed differential double helical gear train

2020 ◽  
Vol 234 (21) ◽  
pp. 4215-4223
Author(s):  
Cheng Wang
Keyword(s):  
Power Flow ◽  
Power Transmission ◽  
Flow Direction ◽  
Load Capacity ◽  
Research Work ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Helical Gear ◽  
Gear Train ◽  
Graph Representation

The research of transmission efficiency is of great significance for reducing energy consumption and improving the performance of the device. Researchers have done a lot of work on the calculation of transmission efficiency. However, in the present research work, the quantity of planetary gear/star gear is usually not considered and only a planetary gear/star gear is adopted in the gear transmission efficiency. In practice, in order to increase the stiffness and load capacity of gear train, a plurality of planetary gear/star gears is adopted. The closed differential double helical gear train has been widely used in many fields, such as the main reducer of aircraft engine, lifting mechanism, and the power transmission system of marine ships. Therefore, in this paper, the closed differential double helical gear train is taken as the research object and the effect of planetary gear/star gear on the transmission efficiency is analyzed. Firstly, according to the structure of closed differential double helical gear train, related kinematic analysis is given. Secondly, a graph representation is used to characterize the closed differential double helical gear train. According to the theory of virtual power, the power flow direction of closed differential double helical gear train is determined and the value of split power is obtained. According to the input and output values described in graph representation of closed differential double helical gear train, the formula of transmission efficiency is derived and the effects of planetary gear/star gear on transmission efficiency are analyzed. Finally, an illustrative example shows that compared with the theoretical value, the difference considering the effect of planetary gear/star gear on the transmission efficiency of closed differential double helical gear train is two percentage points.

Conceptual Design of a 16-Speed Bicycle Drive Hub

2011 ◽  
Vol 52-54 ◽  
pp. 279-284 ◽  
Author(s):  
Yi Chang Wu ◽  
Shi Liang Lin
Keyword(s):  
Conceptual Design ◽  
Kinematic Analysis ◽  
Power Transmission ◽  
Velocity Ratio ◽  
Planetary Gear ◽  
Transmission Mechanism ◽  
Gear Train ◽  
Design Approach ◽  
Schematic Diagram ◽  
Gear Mechanism

This paper presents a design approach for the conceptual design of a novel 16-speed bicycle drive hub. First, a distributed-flow type planetary gear train, which consists of two parallel- connected transmission units and one differential unit, for the power transmission mechanism of a bicycle drive hub is proposed. Based on the kinematic analysis of the presented gear mechanism, a feasible clutching sequence is synthesized to provide 16 forward speeds. Then, the numbers of teeth of all gears are determined according to the desired velocity ratio of each speed. As a result, a schematic diagram of the embodiment of the proposed 16-speed drive hub is presented.

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