Theoretic Study of Efficiency of Two-DOFs of Epicyclic Gear Transmission via Virtual Power

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Chao Chen ◽  
Teck Teh Liang
Keyword(s):  
Design Optimization ◽  
Fundamental Form ◽  
Degrees Of Freedom ◽  
Gear Transmission ◽  
Gear Train ◽  
Mechanical Transmission ◽  
Virtual Power ◽  
Two Degrees Of Freedom ◽  
Analytical Expression ◽  
Epicyclic Gear

Epicyclic gear train is a fundamental form of mechanical transmission with broad applications. Efficiency study of these trains is critical to design, optimization, and operation. It is known that the efficiencies of these systems are highly related to the internal power flows. We apply the concept of virtual power to find analytical expression of the efficiency of a two degrees of freedom train, with associated applicable ranges. The results are verified by an example.

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.

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.

Conceptual Design of Gear Differentials for Automotive Vehicles

1994 ◽  
Vol 116 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Hong-Sen Yan ◽  
Long-Chang Hsieh
Keyword(s):  
Conceptual Design ◽  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Gear Train ◽  
Design Constraints ◽  
Two Degrees Of Freedom ◽  
Design Concepts ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
Gear Differential

An automotive gear differential is a joint-fractionated planetary gear train with two degrees-of-freedom. We summarize the characteristics of planetary gear trains and the design constraints of noncoupled automotive gear differentials to synthesize their corresponding kinematic graphs. Based on these graphs and the proposed respecializing process, we generate the atlas of design concepts for automotive gear differentials with any types of gear pairs. As a result, there are 4, 25, and 156 design concepts for five-, six-, and seven-bar automotive gear differentials, respectively.

Conceptual Design and Optimal Torque Sharing Strategy for Hybrid Vehicles with Epicyclic Gear Trains

2012 ◽  
Vol 152-154 ◽  
pp. 759-764
Author(s):  
Nazim Mir-Nasiri
Keyword(s):  
Degrees Of Freedom ◽  
Combustion Engine ◽  
Power Sharing ◽  
Gear Train ◽  
Ic Engine ◽  
Power Sources ◽  
Epicyclic Gear ◽  
Exhaust Gas Emission ◽  
Wide Range ◽  
Sharing Strategy

The paper presents a novel approach in torque sharing between an internal combustion engine (IC engine) and two electrical motors for optimal drive of a hybrid vehicle. The concept of the system is realized by employing the three degrees of freedom (DOF) twin epicyclic gear train with specially selected gear ratios to satisfy an optimal power sharing strategy. The first stage of the train provides high torque from the IC engine and moderate torque from the motor M1. The second stage provides lower torque but higher speed from the motor M2. Such arrangement of power sources is achieved by carefully selecting of all the gear ratios in the train. The designed system is able to minimize the power usage of the IC engine and thus to minimize the exhaust gas emission, save cost of petrol as compared to normal petrol vehicle. It also provides a quite wide range of torque and speed values to drive the vehicle.

scholarly journals Power-Flow and Mechanical Efficiency Computation in Two-Degrees-of-Freedom Planetary Gear Units: New Compact Formulas

2021 ◽  
Vol 11 (13) ◽  
pp. 5991
Author(s):  
Essam Lauibi Esmail ◽  
Ettore Pennestrì ◽  
Marco Cirelli
Keyword(s):  
Power Flow ◽  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Mechanical Efficiency ◽  
Hybrid Vehicles ◽  
Structural Elements ◽  
Virtual Power ◽  
Two Degrees Of Freedom ◽  
Gear Trains ◽  
The Subject

The mechanical efficiency is a computed value for comparing the performance of the multi degrees-of-freedom geared transmissions of hybrid vehicles. Most of the current methods for estimating gear trains mechanical efficiency require the decomposition of gear transmissions in basic structural elements or planetary gear units (PGU). These are two degrees-of-freedom components whose mechanical efficiency has a deep influence on the overall device. The authors (E.L.E., E.P.) already evidenced that, under certain kinematic conditions, the classic Radzimovsky’s formulas, widely accepted for computing the mechanical efficiency of PGUs, are not adequate. In this paper, more general and reliable formulas for computing the mechanical efficiency are deduced. The proposed formulas herein, exploiting the concept of potential or virtual power, evidence the dependency between kinematics and efficiency. A numerical example compares our results with previous work on the subject.

A Review of Formulas for the Mechanical Efficiency Analysis of Two Degrees-of-Freedom Epicyclic Gear Trains

2003 ◽  
Vol 125 (3) ◽  
pp. 602-608 ◽  
Author(s):  
Ettore Pennestrı` ◽  
Pier Paolo Valentini
Keyword(s):  
Degrees Of Freedom ◽  
Mechanical Efficiency ◽  
Efficiency Analysis ◽  
Rigorous Proof ◽  
Two Degrees Of Freedom ◽  
Epicyclic Gear ◽  
Numerical Equivalence ◽  
Gear Trains

This paper, after a rigorous proof of the formulas originally proposed by Radzimovsky, demonstrates the numerical equivalence of the different approaches available for computing the mechanical efficiency of two degrees-of-freedom (d.o.f.) epicyclic gear trains. The paper includes also a discussion on the redundancy of data required by some formulas.

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.

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