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.

EMBODIMENT DESIGN OF NOVEL 5-SPEED REAR DRIVE HUBS FOR BICYCLES

2015 ◽  
Vol 39 (3) ◽  
pp. 431-441 ◽  
Author(s):  
Yi-Chang Wu ◽  
Tze-Cheng Wu
Keyword(s):  
Power Flow ◽  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Gear Train ◽  
Main Body ◽  
Direct Drive ◽  
Drive Gear ◽  
Planetary Gear Train ◽  
Embodiment Design ◽  
The Relationship

This paper presents embodiment design of 5-speed rear drive hubs for bicycles. A 7-link, 2-degrees of freedom (DOF) compound planetary gear train as the main body of a rear drive hub is introduced. The relationship between the number of coaxial links of a planetary gear train and the number of gear stages that a drive hub can provide with is discussed. By means of kinematic analysis, four speed ratios of the planetary gear train are derived, which represents four forward gears of the rear drive hub. By adding a direct-drive gear, five forward gears can be provided and two feasible clutching sequence tables are synthesized. Manual translational-type gear-shifting mechanisms are further designed to incorporate with the planetary gear train for appropriately controlling the gear stage. The power-flow path at each gear stage is checked to verify the feasibility of the proposed design. Finally, two novel 5-speed bicycle rear drive hubs are presented.

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.

Novel Configurations for Hybrid Transmissions Using a Simple Planetary Gear Train

2015 ◽  
Author(s):  
Huu-Tich Ngo ◽  
Hong-Sen Yan
Keyword(s):  
Hybrid Systems ◽  
Power Flow ◽  
Planetary Gear ◽  
Gear Train ◽  
Design Approach ◽  
Synthesis Process ◽  
Design Constraints ◽  
Planetary Gear Train ◽  
Operation Modes ◽  
Parallel Hybrid

This paper presents a design approach to systematically synthesize feasible configurations for series-parallel and parallel hybrid transmissions subject to design constraints and required operation modes using a simple planetary gear train (PGT). The configuration synthesis process includes two main steps: 1) assign inputs and output powers to the PGT subject to power constraints by the power arrangement process; and 2) assign clutches and brakes to the obtained systems subject to desired operation modes by the clutch arrangement process. By applying the proposed design approach, nine clutchless and 31 clutched configurations for series-parallel and parallel hybrid systems are synthesized, respectively. For each type of the hybrid systems, we analyzed kinematic and power flow of a new configuration to demonstrate the feasibility of the synthesized systems. The design approach can be used to systematically synthesize future hybrid transmissions with different mechanisms, design constraints, and desired operation modes.

Analysis of power flow in a counter-rotating epicyclic gearing for electrical propulsion system

2011 ◽  
Vol 225 (12) ◽  
pp. 2973-2980
Author(s):  
W K Shi ◽  
L J Li ◽  
D T Qin ◽  
T C Lim
Keyword(s):  
Power Distribution ◽  
Power Flow ◽  
Planetary Gear ◽  
Unmanned Vehicles ◽  
Propulsion System ◽  
Gear Train ◽  
Planetary Gear Train ◽  
Differential Gear ◽  
Electrical Propulsion ◽  
Single Input

A novel compound epicyclic gearing that combines a planetary gear train with a differential gear train is designed for an electrical propulsion system of underwater unmanned vehicles. This epicyclic gearing can transform a single input into two counter-rotating outputs with equal torque amplitudes and speeds. Based on the analysis method of power flow in the differential gear train, the character of the power flow of the compound epicyclic gearing was determined. After comparing with the power distribution of input flow, the condition of this mechanism without power recirculation was investigated. Because the reactive torque of the motor stator is balanced by the torque on ring gear of planetary gear train, no net torque acts on the vessel being propelled.

Novel Gear Transmission Mechanism With Twice Unequal Amplitude Transmission Ratio

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Gaohong Yu ◽  
Zhipeng Tong ◽  
Liang Sun ◽  
Junhua Tong ◽  
Xiong Zhao
Keyword(s):  
Structural Characteristics ◽  
Angular Displacement ◽  
Planetary Gear ◽  
Gear Transmission ◽  
Transmission Mechanism ◽  
Gear Train ◽  
Transmission Ratio ◽  
Gear Pair ◽  
Pitch Curve ◽  
Gear Rack

The operation effectiveness of multi-bar transplanting mechanisms is low, and the specific changing law of the transmission ratio (the curve of the transmission ratio has twice unequal amplitude [TUA] fluctuation.), which is needed in vegetable pot seedling transplanting, is difficult to fulfill using a planetary gear train with noncircular gears and a single-planet carrier. To address this problem, we propose a noncircular gear pair that comprises an incomplete noncircular gear, rack, partial noncircular gear, and elliptical gear. The structural characteristics and the working principle of the TUA gear pair were analyzed. The pitch curve equation of the noncircular TUA gears was derived from the relationship of the angular displacement of the corresponding pitch curves. The influence of central angle α and eccentricity k on the shape of the pitch curve, angular displacement, and transmission ratio of the TUA gear pair was analyzed. The TUA gear pair was applied to a proposed vegetable seedling pickup mechanism (SPM) considering the design requirements. Finally, the feasibility of the new noncircular TUA gear transmission mechanism was verified by an SPM test.

scholarly journals Configuration Synthesis of Novel Hybrid Transmission Systems Using a Combination of a Ravigneaux Gear Train and a Simple Planetary Gear Train

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2333 ◽  
Author(s):  
Thanh-Tho Ho ◽  
Sheng-Jye Hwang
Keyword(s):  
Design Methodology ◽  
Power Flow ◽  
Planetary Gear ◽  
Gear Train ◽  
Design Constraints ◽  
Planetary Gear Train ◽  
Operation Modes ◽  
Hybrid Transmission ◽  
Design Requirements ◽  
Configuration Synthesis

Thirty-two novel hybrid transmissions consisting of a Ravigneaux gear train and a single planetary gear train are synthesized using a creative design methodology based on graph-theory and the lever analogy method. The design process commences by identifying an existing transmission configuration which meets all of the design requirements. The chosen design is then used to synthesize all possible mechanism permutations which satisfy the design constraints. The feasible mechanisms which satisfy both the design requirements and the design constraints are converted into analogous levers. The levers which fail to provide the required operation modes of the hybrid transmission are eliminated and the remaining levers are assigned brakes and clutches in order to realize the final designs. The responsiveness of the new hybrid transmissions and the feasibility of the proposed design methodology are confirmed by analyzing the power flow and kinematics of one of the designs in all of the operation modes.

Influence of the Operating Conditions of Two-Degree-of-Freedom Planetary Gear Trains on Tooth Friction Losses

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Essam Lauibi Esmail
Keyword(s):  
Power Loss ◽  
Power Flow ◽  
Planetary Gear ◽  
Operating Conditions ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Friction Loss ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
Two Degree Of Freedom

In a planetary gear train (PGT), the power loss by tooth friction is a function of the potential power developed within the gear train elements rather than that being transmitted through it. In the present work, we focus on the operating conditions of two-degree-of-freedom (two-DOF) PGTs. Any operating condition induces its own internal power flow pattern; this implies that tooth friction loss depends on the mechanism of power loss developed in the gearing that differs from one case to another over the entire range of operating conditions. The approach adopted in this paper stems from a unification of the kinematics and tooth friction losses of PGTs and is based on potential powers and power ratios. The range of applicability of the power relations is investigated and clearly defined, and tooth friction loss formulas obtained by their use are tabulated. A short comparison with formulas currently available in the literature is also made. The simplicity of the proposed method for analyzing two-input or two-output planetary gear trains is helpful in the design, optimization, and control of hybrid transmissions. It assists particularly in choosing correctly the appropriate operating conditions to the involved application.

Design of a non circular gear Mechanism with Twice Unequal Amplitude Transmission Ratio

2022 ◽  
pp. 1-13
Author(s):  
Jiangang Liu ◽  
Zhipeng Tong ◽  
Yu Gao-hong ◽  
Xiong Zhao ◽  
Haili Zhou
Keyword(s):  
High Speed ◽  
Planetary Gear ◽  
Tooth Profile ◽  
Gear Transmission ◽  
Gear Train ◽  
Transmission Ratio ◽  
High Speed Camera ◽  
Contact Ratio ◽  
Ratio Curve ◽  
Amplitude Transmission

Abstract This study proposes a new non–circular gear transmission mechanism with an involute–cycloid composite tooth profile to realize the twice unequal amplitude transmission (In a complete rotation cycle of gear transmission, instantaneous transmission ratio has twice fluctuations obvious with unequal amplitude) of non–circular gears. The twice unequal amplitude transmission ratio curve was designed based on Fourier and polynomial functions, the change law of the Fourier coefficient on the instantaneous transmission ratio(In non-circular gear transmission, the transmission ratio changes with time, and the transmission ratio of non-circular gear should be instantaneous transmission ratio) was analyzed, and the pressure angle and contact ratio of the involute–cycloid composite tooth profile was calculated. The involute–cycloid composite tooth profile non–circular gear was machined by WEDM technology, while its meshing experiment was performed using high-speed camera technology. The results demonstrate that the instantaneous transmission ratio curve value obtained via the high-speed camera experiment was consistent with the simulation value of virtual software. Furthermore, the involute–cycloid composite tooth profile was applied in the seedling pickup mechanism of non–circular gear planetary gear train. The possibility of the application of the involute–cycloid composite tooth profile in the seedling pickup mechanism was verified by comparing the consistency of the theoretical and simulated seedling picking trajectory.

Multi-Objective Optimization for the Efficiency and Weight of Helicopter Transmission Planetary Gear Train

2014 ◽  
Vol 635-637 ◽  
pp. 177-180
Author(s):  
Kang Huang ◽  
Xiao Hui Zhu ◽  
Xiang Chen ◽  
Gong Chuan Xia
Keyword(s):  
Planetary Gear ◽  
Optimization Method ◽  
Gear Train ◽  
Transmission Ratio ◽  
Design Parameters ◽  
Multi Objective Optimization ◽  
Planetary Gear Train ◽  
Multi Objective ◽  
Critical Design ◽  
Helicopter Transmission

A multi-objective optimization method for the optimization of the efficiency and weight of helicopter transmission planetary gear train was established. Taking the transmission ratio, efficiency weight, and reliability as critical design parameters, taking the conditions of the planetary gear train itself and the strength check constraint for the gear train as constraint functions, making the weight and efficiency of the planetary gear train asoptimization targets and using the Matlab function fgoalattain, a multi-objective optimization has been made. Comparison between the initial and the optimized results showed the success of the optimized planetary gear train in reducing the weight and increasing the efficiency.

Mechanical Efficiency Analysis of a 16-Speed Bicycle Transmission Hub

2013 ◽  
Vol 284-287 ◽  
pp. 810-814 ◽  
Author(s):  
Yi Chang Wu ◽  
Pei Wun Ren
Keyword(s):  
Analytical Method ◽  
Power Flow ◽  
Planetary Gear ◽  
Mechanical Efficiency ◽  
Angular Speed ◽  
Efficiency Analysis ◽  
Gear Train ◽  
Flow Diagram ◽  
Gear Mesh ◽  
Analysis Process

This paper proposes an analytical method to evaluate the mechanical efficiency of the bicycle transmission hub. A 16-speed transmission hub, which consists of two transmission units and one differential unit, is presented first. By applying the concept of fundamental circuits, a step by step analysis process is then described to numerically calculate the angular speed, ideal torque and power flow, and actual torque and power flow by considering the gear-mesh loss of each link of the planetary gear train. Based on the power flow diagram, the mechanical efficiency at each speed of the transmission hub can be estimated.

Sign in / Sign up

Export Citation Format

Share Document