scholarly journals Effect of mesh phasing on the transmission efficiency and dynamic performance of wheel hub planetary gear sets

2017 ◽  
Vol 232 (19) ◽  
pp. 3469-3481 ◽  
Author(s):  
Ehsan Fatourehchi ◽  
Mahdi Mohammadpour ◽  
Paul D King ◽  
Homer Rahnejat ◽  
Gareth Trimmer ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Gear Teeth ◽  
Design Attributes ◽  
Frictional Performance ◽  
Planetary Gear Sets ◽  
Noise Vibration ◽  
New Generation ◽  
Mesh Phasing

Transmission efficiency and refinement of planetary wheel hub gearing system are key design attributes for heavy and off-highway vehicles. Reduction of power loss, directly leading to the development of new generation ECO-axles requires analysis of gear contacting conditions for lubricated conjunctions to determine frictional performance. This is also affected by gear dynamics, which is a prerequisite for assessment of noise, vibration and harshness performance. Therefore, a combined tribo-dynamic analysis is essential. There is a dearth of such holistic analysis, particularly for the case of wheel hub planetary systems. The paper presents such an analysis, which has not hitherto been reported in literature. The inexorable interplay of transmission efficiency and noise, vibration and harshness refinement is demonstrated. The key attributes of noise, vibration and harshness refinement and transmission efficiency can pose contrary requirements and near-optimal conditions can be highlighted by mesh phasing of gearing contacts, thus alleviating the need for more complex gear teeth modifications entailing prohibitive manufacturing costs.

scholarly journals Dynamics and efficiency of planetary gear sets for hybrid powertrains

2015 ◽  
Vol 230 (7-8) ◽  
pp. 1359-1368 ◽  
Author(s):  
M Mohammadpour ◽  
S Theodossiades ◽  
H Rahnejat
Keyword(s):  
Electric Motor ◽  
Hybrid Electric Vehicle ◽  
Combustion Engine ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Drive Mode ◽  
Planetary Gear Sets ◽  
Hybrid Electric ◽  
Noise Vibration ◽  
Six Degree Of Freedom

The paper presents a tribo-dynamic model for planetary gear sets of hybrid-electric-vehicle configurations. The model comprises a six degree-of-freedom torsional multi-body dynamic system, as well as a tribological contact model in order to evaluate the lubricant film thickness, friction and efficiency of the meshing gear teeth contacts. The tribological model takes into account the non-Newtonian, thermal-mixed elastohydrodynamic regime of lubrication. Analysis is performed for a hybrid electric C-segment vehicle. The simulated conditions correspond to cases of power supplied by either the engine or the electric motor. The results illustrate that in the electric motor drive mode, improved noise, vibration and harshness refinement would be expected, whereas better transmission efficiency is achieved in the internal combustion engine drive mode.

An Analytical and Numerical Investigation of Modulation Sidebands of a Planetary Gear Under Fluctuated External Torque

2018 ◽  
Author(s):  
Yunbo Yuan ◽  
Wei Liu ◽  
Yahui Chen ◽  
Donghua Wang
Keyword(s):  
Planetary Gear ◽  
Transmission Error ◽  
Operating Conditions ◽  
Radial Acceleration ◽  
External Torque ◽  
Gear Mesh ◽  
Planetary Gear Sets ◽  
Static Transmission Error ◽  
Frequency Modulations ◽  
Mesh Phasing

Certain operating conditions such as fluctuation of the external torque to planetary gear sets can cause additional sidebands. In this paper, a mathematical model is proposed to investigate the modulation mechanisms due to a fluctuated external torque (FET), and the combined influence of such an external torque and manufacturing errors (ME) on modulation sidebands. Gear mesh interface excitations, namely gear static transmission error excitations and time-varying gear mesh stiffness, are defined in Fourier series forms. Amplitude and frequency modulations are demonstrated separately. The predicted dynamic gear mesh force spectra and radial acceleration spectra at a fixed position on ring gear are both shown to exhibit well-defined modulation sidebands. Comparing with sidebands caused by ME, more complex sidebands appear when taking both FET and ME into account. An obvious intermodulation is found around the fundamental gear mesh frequency between the FET and ME in the form of frequency modulations, however, no intermodulation in the form of amplitude modulations. Additionally, the results indicate that some of the sidebands are cancelled out in radial acceleration spectra mainly due to the effect of planet mesh phasing, especially when only amplitude modulations are present.

Investigation on the influence of spalling defects on the dynamic performance of planetary gear sets with sliding friction

2021 ◽  
Vol 154 ◽  
pp. 106639
Author(s):  
Wei Luo ◽  
Baijie Qiao ◽  
Zhixian Shen ◽  
Zhibo Yang ◽  
Hongrui Cao ◽  
...  
Keyword(s):  
Sliding Friction ◽  
Dynamic Performance ◽  
Planetary Gear ◽  
Planetary Gear Sets

Fuzzy Reliablity Optimization Design of Two Stage Planetary Gear System by Genetic Algorithm Based on Predatory Search Strategy

2011 ◽  
Vol 403-408 ◽  
pp. 743-747 ◽  
Author(s):  
Chun Guang Wang
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Model ◽  
Reliability Analysis ◽  
Optimization Design ◽  
Search Strategy ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Fuzzy Reliability ◽  
Two Stage ◽  
Planetary Gear Sets

Fuzzy reliability analysis is regared as the theoretical basis. It takes the minimum volume and the maximum transmission efficiency as objective function．Then the mathematical model of fuzzy reliability optimal design on two stage planetary gear sets is set up. Genetic algorithm based on predatory search strategy is used to solve the fuzzy reliability mathematical model. Examples of calculation shows that the volume is decrease by 15%. The results imply the fuzzy reliability analysis is more scientific and reasonable in designing two stage planetary gear sets by using fuzzy reliability analysis.

scholarly journals Multiphysics Investigations on the Dynamics of Differential Hypoid Gears

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
M. Mohammadpour ◽  
S. Theodossiades ◽  
H. Rahnejat
Keyword(s):  
Multiscale Analysis ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Transmission Efficiency ◽  
Operating Conditions ◽  
Hypoid Gear ◽  
Tooth Contact Analysis ◽  
Hypoid Gears ◽  
Gear Teeth ◽  
Noise Vibration

Vehicular differential hypoid gears play an important role on the noise, vibration, and harshness (NVH) signature of the drivetrain system. Additionally, the generated friction between their mating teeth flanks under varying load-speed conditions is a source of power loss in a drivetrain while absorbing some of the vibration energy. This paper deals with the coupling between system dynamics and analytical tribology in multiphysics, multiscale analysis. Elastohydrodynamic lubrication (EHL) of elliptical point contact of partially conforming hypoid gear teeth pairs with non-Newtonian thermal shear of a thin lubricant film is considered, including boundary friction as the result of asperity interactions on the contiguous surfaces. Tooth contact analysis (TCA) has been used to obtain the input data required for such an analysis. The dynamic behavior and frictional losses of a differential hypoid gear pair under realistic operating conditions are therefore determined. The detailed analysis shows a strong link between NVH refinement and transmission efficiency, a finding not hitherto reported in literature.

scholarly journals Vibration Based Diagnosis for Planetary Gearboxes Using an Analytical Model

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Liu Hong ◽  
Yongzhi Qu ◽  
Yuegang Tan ◽  
Mingyao Liu ◽  
Zude Zhou
Keyword(s):  
Analytical Model ◽  
Planetary Gear ◽  
Diagnostic Techniques ◽  
Dynamic Simulations ◽  
Diagnostic Efficacy ◽  
Planetary Gearbox ◽  
Gear Teeth ◽  
Detection And Identification ◽  
Planetary Gear Sets ◽  
Frequency Components

The application of conventional vibration based diagnostic techniques to planetary gearboxes is a challenge because of the complexity of frequency components in the measured spectrum, which is the result of relative motions between the rotary planets and the fixed accelerometer. In practice, since the fault signatures are usually contaminated by noises and vibrations from other mechanical components of gearboxes, the diagnostic efficacy may further deteriorate. Thus, it is essential to develop a novel vibration based scheme to diagnose gear failures for planetary gearboxes. Following a brief literature review, the paper begins with the introduction of an analytical model of planetary gear-sets developed by the authors in previous works, which can predict the distinct behaviors of fault introduced sidebands. This analytical model is easy to implement because the only prerequisite information is the basic geometry of the planetary gear-set. Afterwards, an automated diagnostic scheme is proposed to cope with the challenges associated with the characteristic configuration of planetary gearboxes. The proposed vibration based scheme integrates the analytical model, a denoising algorithm, and frequency domain indicators into one synergistic system for the detection and identification of damaged gear teeth in planetary gearboxes. Its performance is validated with the dynamic simulations and the experimental data from a planetary gearbox test rig.

A Load Distribution Model for Planetary Gear Sets

2017 ◽  
Author(s):  
Yong Hu ◽  
David Talbot ◽  
Ahmet Kahraman
Keyword(s):  
Load Distribution ◽  
Planetary Gear ◽  
Distribution Model ◽  
Component Level ◽  
Gear Mesh ◽  
Position Errors ◽  
Unequally Spaced ◽  
Planetary Gear Sets ◽  
Mesh Phasing ◽  
Gear Meshes

Here, a load distribution model of planetary gear sets is presented capable of dealing with planetary gear sets with any component level and gear set level design variations such as component supporting conditions, different kinds of gear modifications and planetary gear sets with different numbers of equally or unequally spaced planets as well as different gear set kinematic configurations while considering gear mesh phasing. It also accounts for classes of planetary gear set manufacturing and assembly related errors associated with the carrier or gears, i.e. pinhole position errors, run-out errors and tooth thickness errors. Example analyses are provided to indicate the need for a model of this type when studying load distribution of planetary gear sets due to unique loading of the gear meshes associated with planetary gear sets. Comparisons to measurements existing in the literature are provided.

scholarly journals Quasi-Static Load Sharing Characteristics of a Planetary Gear Set with Planet Journal Bearings

2020 ◽  
Vol 10 (3) ◽  
pp. 1113
Author(s):  
Zhiqiang Guo ◽  
Shenlong Li ◽  
Wei Wu ◽  
Liuyang Zhang
Keyword(s):  
Static Load ◽  
Dynamic Performance ◽  
Planetary Gear ◽  
Load Sharing ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Computation Method ◽  
Analysis Method ◽  
Planetary Gear Sets ◽  
Bearing Stiffness

The quasi-static load sharing characteristics of a planetary gear set with planet journal bearings are numerically investigated. The application of journal bearings instead of rolling bearings in planetary gear sets is an alternative to increase the rotation speed. Therefore, an effective analysis method is needed to estimate the dynamic performance of a planetary gear set with planet journal bearings. Here, an available load sharing factor computation method is developed considering the effect of the variable journal bearing stiffness. Results of an experiment are used to validate the effectiveness of the computation method. Furthermore, the load sharing characteristics of a planetary gear set with planet journal bearings are influenced by bearing parameters and operating conditions significantly due to the changing bearing stiffness of journal bearings. The effects on the load sharing factor and the bearing stiffness are studied in detail simultaneously based on the proposed analysis method. The load sharing factor of a planetary gear set with planet journal bearings has a similar variation with the bearing support stiffness under the same load. These researches provide a theoretical basis for the application of journal bearings in planetary gear sets.

Planetary Gear Train Dynamics

1994 ◽  
Vol 116 (3) ◽  
pp. 713-720 ◽  
Author(s):  
A. Kahraman
Keyword(s):  
Dynamic Behavior ◽  
Linear Time ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Planetary Gear ◽  
Gear Train ◽  
Planetary Gear Train ◽  
Gear Teeth ◽  
Linear Time Invariant ◽  
Mesh Phasing

A model to simulate the dynamic behavior of a single-stage planetary gear train with helical gears is developed. The three-dimensional dynamic model includes all six rigid body motions of the gears and the carrier. The generic nature of the formulation allows the analysis of a planetary gear set with any number of planets. Planets can be arbitrarily spaced (equally or unequally) around the sun gear. The model is also capable of handling different planet meshing conditions which are functions of number of gear teeth and planet positions. The linear time-invariant equations of motion are solved to obtain the natural modes and the forced vibration response due to static transmission errors. The proposed model is employed to describe the effects of the planet mesh phasing conditions on the dynamic behavior of a four-planet system.

A study on the development and application of program for planetary gear design considering planetary gear noise and efficiency

2021 ◽  
Vol 263 (5) ◽  
pp. 1516-1526
Author(s):  
Hyun Ku Lee ◽  
Moo Suk Kim ◽  
Sa Man Hong ◽  
Dong Kyu Yoo ◽  
Ahmet Kahraman ◽  
...  
Keyword(s):  
Input Parameter ◽  
Automatic Transmission ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Design Stage ◽  
Concept Design ◽  
Mechanical Loss ◽  
Gear Noise ◽  
Gear Design ◽  
Planetary Gear Sets

In general, gear mechanical loss is associated with the friction of the lubricating contact surface of the gear and bearing that transmit the power, and a no-load spin loss which is load independent occurs due to gear rotation and the interaction of the bearing component with the lubricating element. In order to minimize planetary gear loss, it is desirable to design by checking the efficiency at the concept design stage. However, a design technique that considers the noise and efficiency of a planetary gear set simultaneously has not been achieved so far. In this paper, a program called 'pRMC with EHL' to check together the efficiency and noise that affected by gear specifications has been developed. By using developed program, planetary gear sets specifications have been designed. And through the experimental evaluation, automatic transmission efficiency could be reduced by 0.3% in combination fuel consumption mode and the planetary gear vibration could be also reduced by 10 dB than former design. Through this designing verification and input parameter correlation, a new planetary gear set designing process has been come up with successfully at the concept design stage.

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