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.

scholarly journals A calculation method of transmission efficiency for RV reducer

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Cheng Wang ◽  
Keyword(s):  
Calculation Method ◽  
Industrial Robot ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Gear Train ◽  
Graph Representation ◽  
Design Parameters ◽  
Virtual Power ◽  
Power Theory ◽  
Rv Reducer

RV reducer is the core component of industrial robot. It is of great significance to raise the transmission efficiency of RV reducer for improving the transmission performance of industrial robot. RV reducer belongs to the 2K-V type planetary gear train and consists of an equal speed ratio mechanism. Therefore, according to the structural characteristics of RV reducer, the virtual power theory and split power theory are adopted, and a calculation method of transmission efficiency for RV reducer is proposed. Firstly, the structure of a common RV reducer is introduced. Related structural analysis, kinematic analysis, and loaded analysis are given. Secondly, RV reducer is represented by the method of graph theory. By the virtual power theory and split power theory, the power flow direction is determined, and the values of split powers are calculated. Finally, according to the graph representation for RV reducer and the calculation principle of meshing power loss of planetary gear, the power losses of meshing gear pairs are calculated, respectively. According to the input and output values described in graph representation of RV reducer, the formula of transmission efficiency for RV reducer is derived. The calculation of transmission efficiency for RV-40E reducer is considered as an example. The result is compared with previous work on the subject, and the relations between design parameters and transmission efficiency of RV reducer are discussed.

A New Technique Based on Loops to Investigate Displacement Isomorphism in Planetary Gear Trains

2002 ◽  
Vol 124 (4) ◽  
pp. 662-675 ◽  
Author(s):  
V. V. N. R. Prasad Raju Pathapati ◽  
A. C. Rao
Keyword(s):  
Graph Isomorphism ◽  
Planetary Gear ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Graph Representation ◽  
Kinematic Structure ◽  
Graph Representations ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
A New Technique

The most important step in the structural synthesis of planetary gear trains (PGTs) requires the identification of isomorphism (rotational as well as displacement) between the graphs which represent the kinematic structure of planetary gear train. Previously used methods for identifying graph isomorphism yielded incorrect results. Literature review in this area shows there is inconsistency in results from six link, one degree-of-freedom onwards. The purpose of this paper is to present an efficient methodology through the use of Loop concept and Hamming number concept to detect displacement and rotational isomorphism in PGTs in an unambiguous way. New invariants for rotational graphs and displacement graphs called geared chain hamming strings and geared chain loop hamming strings are developed respectively to identify rotational and displacement isomorphism. This paper also presents a procedure to redraw conventional graph representation that not only clarifies the kinematic structure of a PGT but also averts the problem of pseudo isomorphism. Finally a thorough analysis of existing methods is carried out using the proposed technique and the results in the category of six links one degree-of-freedom are established and an Atlas comprises of graph representations in conventional form as well as in new form is presented.

Meshing Efficiency Analysis of Two Degree-of-Freedom Epicyclic Gear Trains

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Essam Lauibi Esmail
Keyword(s):  
Reference Frame ◽  
Power Efficiency ◽  
Power Flow ◽  
Flow Direction ◽  
Efficiency Analysis ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
Two Degree Of Freedom

The concept of potential power efficiency is introduced as the efficiency of an epicyclic gear train (EGT) measured in any moving reference frame. The conventional efficiency can be computed in a carrier-moving reference frame in which the gear carrier appears relatively fixed. In principle, by attaching the reference frame to an appropriate link, torques can be calculated with respect to each input, output, or (relatively) fixed link in the EGT. Once the power flow direction is obtained from the potential power ratio, the torque ratios are obtained from the potential power efficiencies, the particular expression of the efficiency of the EGT is found in a simple manner. A systematic methodology for the efficiency analysis of one and two degree-of-freedom (DOF) EGTs is described, and 14 ready-to-use efficiency formulas are derived for 2DOF gear pair entities (GPEs). This paper includes also a discussion on the redundancy of the efficiency formulas used for 1DOF GPEs. An incomplete in the efficiency formulas in previous literature, which make them susceptible to wrong application, is brought to light.

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 Research on Transmission Characteristics of Hydromechanical Continuously Variable Transmission of Tractor

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Junyan Wang ◽  
Changgao Xia ◽  
Xin Fan ◽  
Junyu Cai
Keyword(s):  
Power Flow ◽  
Flow Direction ◽  
Transmission Efficiency ◽  
Continuously Variable Transmission ◽  
Simulation Software ◽  
Transmission Scheme ◽  
Compact Structure ◽  
Theoretical Derivation ◽  
Speed Regulation ◽  
Variable Transmission

This paper proposes a new transmission scheme of hydromechanical continuously variable transmission (HMCVT) for tractors. The HMCVT has 4 working ranges in each of the front and rear directions. The speed characteristic and the torque characteristic of HMCVT are theoretically derived. On the basis of HMCVT power flow direction, the Крейнeс formula is used to calculate the transmission efficiency. Then, the image analysis method is used to study the influence of parameters on the transmission efficiency of HMCVT, and the main influencing factors are found. The results of theoretical derivation demonstrate that, by coordinating control of the HST displacement ratio and the engagement conditions of shifting clutches, the stepless speed regulation of HMCVT at the tractor speed of 0–50 km/h can be realized. The proposed HMCVT has the ability to continuously transmit and change torque over all working ranges. The overall transmission efficiency of HMCVT is at a high level. To verify the theoretical derivation, Amesim simulation software is used for the modeling and simulation of HMCVT. The simulation results are consistent with the theoretical analysis results. Therefore, the HMCVT proposed in this paper has the advantages of compact structure and high transmission efficiency, and it is suitable for matching tractors.

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.

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.

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.

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