Nomographs for Kinematics, Statics and Power Flow Analysis of Epicyclic Gear Trains

2009 ◽  
Author(s):  
Essam L. Esmail ◽  
Hamed A. Hussen
Keyword(s):  
Electric Motor ◽  
Power Flow ◽  
Automatic Transmission ◽  
Flow Analysis ◽  
Gear Train ◽  
Innovative Design ◽  
Epicyclic Gear ◽  
Power Split ◽  
Gear Trains ◽  
Flow Through

A new methodology for constructing multi-axes nomographs is developed. Using this methodology, a unified general formulation for computing velocities and torques of any epicyclic-type transmission train is presented. To demonstrate and apply the new technique, Ravigneaux automatic transmission is used to show how the velocities, the torques and the power flow through the train can be simultaneously visualized on a single nomograph. The present methodology is judged to be more efficient than other methods and than the three-ax nomograph methodology. Using this methodology an innovative design of two-input transmission with only one electric motor/generator (MG) and without any rotating clutches is presented. The proposed design provides some of the benefits and flexibility of a power-split design by using the conventionally available Ravigneaux gear train in a simpler mechanical layout which makes the design compact, mechanically simple, and operationally flexible.

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.

A Simplified Approach for Force and Power-Flow Analysis of Compound Epicyclic Spur-Gear Trains

1992 ◽  
Author(s):  
L. Saggere ◽  
D. G. Olson
Keyword(s):  
Graph Theory ◽  
Kinematic Analysis ◽  
Power Flow ◽  
Flow Analysis ◽  
Spur Gear ◽  
Gear Train ◽  
Force Analysis ◽  
Power Flow Analysis ◽  
Torque Analysis ◽  
Gear Trains

Abstract After conceptual design and dimensional synthesis of a compound epicyclic gear train (EGT), its performance evaluation involves kinematic analysis, force analysis, torque analysis, and power-flow analysis. In recent years, graph theory has proven to be a powerful symbolic representation for design of mechanisms. Application of graph theory for the topological representation and kinematic analysis of EGTs is quite well established. However, graph theory based methods for power-flow and force analysis lack certain features, making them unsuitable or difficult to implement in a general purpose program for automatic design of EGTs. The traditional approach has been to perform force and torque analysis first, and then use the results to perform power-flow analysis. This paper presents a novel, systematic approach in which power-flow analysis is performed first, and then the results are used to determine the inter-link forces in epicyclic spur-gear trains. This method is based only on the graph of the gear-train and the angular velocities of the elements, and hence, is more suitable for automatic computation, simpler to implement in a program, and also avoids requiring the formulation of tedious torque equilibrium equations. A numerical example is presented to illustrate the simplicity and generality of the method.

Torque and Power-Flow Analyses of Two Input Epicyclic-Type Transmission Trains

2008 ◽  
Author(s):  
Essam L. Esmail ◽  
Shaker S. Hassan
Keyword(s):  
Power Flow ◽  
Flow Analysis ◽  
Gear Train ◽  
Root Cause ◽  
Transmission Design ◽  
Epicyclic Gear ◽  
Systematic Methodology ◽  
Hybrid Transmission ◽  
The Given ◽  
Input Torque

This study contributes to the development of a systematic methodology for the torque and power flow analyses of two-input epicyclic gear mechanisms (EGMs) with or without reaction link, based upon the concept of fundamental circuit. The studies on power flow analysis of EGMs are mostly done in the context of efficiency formulations. In the opinion of the authors, the design process of two-input mechanism involves not only finding the configuration that provides the correct velocity ratios, but also meets other dynamic and kinematic requirements and ensures that the two inputs have a mutually constructive nature. To demonstrate the analysis, a new motor/generator integrated hybrid transmission design is used to show how the torque acting on each link of an epicyclic gear train (EGT) can be systematically solved in terms of input torque(s) and/or controlled output torque. This paper presents a unification of kinematic and torque balance approaches for the analysis of two-input epicyclic-type transmission trains. The results presented are meant to deepen the knowledge as to how and why a two-input epicyclic-type transmission should operate in a certain way under the given conditions. In the process, this paper explores the theoretical bases of operation of the Toyota Hybrid System (THS) and the root cause of some confusion in the field of EGTs.

Complete Efficiency Analysis of Epicyclic Gear Train With Two Degrees of Freedom

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Kieran Davies ◽  
Chao Chen ◽  
Bernard K. Chen
Keyword(s):  
Optimal Design ◽  
Power Flow ◽  
Degrees Of Freedom ◽  
Efficiency Analysis ◽  
Operating Conditions ◽  
Gear Train ◽  
Virtual Power ◽  
Two Degrees Of Freedom ◽  
Epicyclic Gear ◽  
Gear Trains

Epicyclic gear trains (EGTs) are important mechanical transmissions with many applications. For optimal design and operation of these gear trains, it is necessary to obtain complete efficiency maps of such transmissions. The efficiency of a two degrees of freedom (two-dof) EGT is derived based on the internal power flow and virtual power flow patterns. Expressions for the efficiencies in different operating conditions are obtained and verified by three special conditions.

Virtual-Power Flow and Mechanical Gear-Mesh Power Losses of Epicyclic Gear Trains

2006 ◽  
Vol 129 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Chao Chen ◽  
Jorge Angeles
Keyword(s):  
Power Loss ◽  
Power Flow ◽  
Gear Train ◽  
Power Losses ◽  
Virtual Power ◽  
Noninertial Frame ◽  
Gear Mesh ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
The Subject

The concept of virtual power is first defined as the power measured, in a noninertial frame, in an epicyclic gear train. We then introduce the concept of virtual-power ratio, an invariant related to the power loss in an epicyclic system. It is shown that virtual-power flow and balance exist in an epicyclic gear train, based on which a novel algorithm to compute the gear-mesh powerloss and the train efficiency is formulated. This algorithm is general enough to be applied to any given epicyclic gear train. Our results are compared with previous work on the subject.

An Approach to Power-Flow and Static Force Analysis in Multi-Input Multi-Output Epicyclic-Type Transmission Trains

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Essam L. Esmail ◽  
Shaker S. Hassan
Keyword(s):  
Power Flow ◽  
Flow Analysis ◽  
Gear Train ◽  
Root Cause ◽  
Transmission Design ◽  
Epicyclic Gear ◽  
Systematic Methodology ◽  
Hybrid Transmission ◽  
The Given ◽  
Input Torque

This study contributes to the development of a systematic methodology for the torque and power-flow analyses of multi-input multi-output (MIMO) epicyclic gear mechanisms (EGMs) with or without reaction link based on the concept of fundamental circuit. The studies on power-flow analysis of EGMs are mostly done in the context of efficiency formulations. In the opinion of the authors, the design process of the MIMO mechanism involves not only finding the configuration that provides the correct velocity ratios but also meeting other kinematic requirements and ensuring that the two inputs have a mutually constructive nature. To demonstrate the analysis, a new motor/generator integrated hybrid transmission design is used to show how the torque acting on each link of an epicyclic gear train (EGT) can be systematically solved in terms of input torque(s) and/or controlled output torque. This paper presents a unification of kinematic and torque balance approaches for the analysis of MIMO epicyclic-type transmission trains. The results presented are meant to deepen the knowledge as to how and why a MIMO epicyclic-type transmission should operate in a certain way under the given conditions. In the process, this paper explores the theoretical bases of operation of the Toyota Hybrid System and the root cause of some confusion in the field of EGTs.

Power Flow Analysis of Compound Epicyclic Gear Transmission: Simpson Gear Train

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Chao Chen
Keyword(s):  
Power Flow ◽  
Flow Analysis ◽  
Gear Transmission ◽  
Gear Train ◽  
Total Efficiency ◽  
Virtual Power ◽  
Speed Reduction ◽  
Power Flow Analysis ◽  
Epicyclic Gear ◽  
The Individual

An analytical expression for the total efficiency of the Simpson gear train is derived using virtual power analysis. This expression is consistent with intuition when the total efficiency is 100%. Power flow analysis shows that there are no internal power circulation and amplification in the Simpson gear train. Analysis based on the derived efficiency formula shows that the total efficiency of the Simpson gear transmission is more sensitive to the individual gear efficiencies when the speed reduction is higher.

A Generalized Kinematics and Power Flow Analysis Methodology for Automatic Transmission Gear Trains

2003 ◽  
Author(s):  
A. Kahraman ◽  
K. Kienzle ◽  
D. M. Zini
Keyword(s):  
Power Flow ◽  
Search Algorithm ◽  
Gear Tooth ◽  
Automatic Transmission ◽  
Flow Analysis ◽  
Planetary Gear ◽  
Gear Train ◽  
Power Flow Analysis ◽  
Planetary Gear Sets ◽  
Transmission Gear

A generalized formulation for analyzing speeds and forces of the gear components of planetary automatic transmissions is proposed. The formulation is capable of analyzing any typical one-degree-of-freedom automatic transmission gear train containing any number of simple, compound or complex-compound planetary gear sets. It consists of three components: a kinematic analysis formulation, a gear ratio and kinematic configuration search algorithm, and a power flow analysis formulation. The kinematics module computes rotational speeds of gears and carriers. Given the type and number of planetary gear sets, the search module determines all possible kinematic configurations and gear tooth count combinations that result in a required set of gear ratios while eliminating all kinematic redundancies and unfavorable clutching sequences. The third component, the power-flow analysis formulation, performs a complete static force (power flow) analysis to determine all gear and bearing forces, and clutch and connection torque values. A five-speed transmission example is considered to highlight the capabilities of the proposed formulation.

scholarly journals Power Flow Simulation for Two-Degree-of-Freedom Planetary Gear Transmissions with Experimental Validation

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Hamed Ali Hussen ◽  
Essam Lauibi Esmail ◽  
Rahman A. Hussen
Keyword(s):  
Power Flow ◽  
Flow Simulation ◽  
Planetary Gear ◽  
Gear Train ◽  
Total Power ◽  
Power Amplification ◽  
Gear Trains ◽  
Study Power ◽  
Flow Through ◽  
Insight Into

The basic relationships among gear ratios, velocity succession, torque directions, power ratios, energy losses, and efficiency are derived from first principles. The techniques presented here can be applied to ordinary, planetary, or mixed gear trains. Also, these techniques provide more insight into how power is flowing through the different parts of the mechanism. Power flow relationships are a helpful tool to study power amplification and power circulation in multipath transmissions. They also provide more insight into how the gear pair entities (GPEs) or gear train entities (GTEs) affect total power losses and allow immediate derivation of the overall efficiency. A representative two-input mechanism is analyzed to demonstrate the effectiveness of improved techniques. The theoretical results are compared with experimental data of previous work. The theoretical and experimental curves exhibit identical trends with a distinct jump in friction loss. The jump is explained by a change in the way of the power flow through the mechanism. The conditions under which power circulation occurs are determined. The results have important implications for understanding how to improve the efficiency of multipath power flow systems.

Sign in / Sign up

Export Citation Format

Share Document