Influence of Design Parameters on Mechanical Power Losses of Planetary Gear Sets

2015 ◽  
Author(s):  
H. S. Kwon ◽  
A. Kahraman
Keyword(s):  
Mechanical Load ◽  
Search Algorithm ◽  
Film Formation ◽  
Planetary Gear ◽  
Design Parameters ◽  
Power Losses ◽  
Gear Design ◽  
Gear Mesh ◽  
Profile Correction ◽  
Planetary Gear Sets

Mechanical (load-dependent) power losses of a planetary gear set occurs primarily along its lubricated rolling-sliding interfaces at the external and internal gear meshes, and planet bearings. The gear mesh originated portion of these losses are influenced by all key gear parameter, tooth profile correction and other parameters dictating the fluid film formation. In this study, a systematic planetary gear design search algorithm is combined with an efficiency formulation to (i) quantify the sensitivity of gear mesh mechanical losses of planetary gear sets to the basic gear design parameters and (ii) investigate the compromise that must take place between the mechanical efficiency and other functional attributes associated with durability and noise performance of the gear set. An example design study is presented at the end to demonstrate both of these points.

An Automated Design Search for Single and Double-Planet Planetary Gear Sets

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
H. S. Kwon ◽  
A. Kahraman ◽  
H. K. Lee ◽  
H. S. Suh
Keyword(s):  
Performance Metrics ◽  
Gear Tooth ◽  
Planetary Gear ◽  
Automated Design ◽  
Geometric Design ◽  
System Level ◽  
Design Parameters ◽  
Tooth Contact Analysis ◽  
Gear Mesh ◽  
Planetary Gear Sets

Design of planetary gear sets is more involved than the design of their counter-shaft counterparts as it involves simultaneous design of a set of internal and external gear meshes while complying with a large number of systems and gear mesh related requirements for assembly, durability, noise, and efficiency. A manual iterative design process often results in suboptimal designs that fail to meet all these requirements simultaneously. In this paper, a methodology for an automated design search of single and double-planet planetary gear sets is proposed. With the input of a number of system-level constraints associated with the spacing and phasing of the planets, and acceptable ranges of basic geometric design parameters, this methodology defines a large design space in that a large number of geometric design concepts are identified and checked for any interferences. The external and internal meshes of these concepts are evaluated by using computationally efficient loaded gear tooth contact analysis model to predict their performance metrics such as transmission error amplitudes and contact and root stresses. They are then rank-ordered based on their performance metrics to identify balanced planetary gear set designs meeting all requirements equally well. At the end, results of an example design search were presented to demonstrate the effectiveness of the proposed methodology in defining a balanced solution that is acceptable in terms of all of its requirements.

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.

A Three-Dimensional Load Sharing Model of Planetary Gear Sets Having Manufacturing Errors

2015 ◽  
Author(s):  
Nicholas D. Leque ◽  
Ahmet Kahraman
Keyword(s):  
Three Dimensional ◽  
Planetary Gear ◽  
Load Sharing ◽  
Distribution Model ◽  
Gear Mesh ◽  
Position Errors ◽  
Proposed Model ◽  
Manufacturing Errors ◽  
Manufacturing Tolerancing ◽  
Planetary Gear Sets

Planet-to-planet load sharing is a major design and manufacturing tolerancing issue in planetary gear sets. Planetary gear sets are advantageous over their countershaft alternatives in many aspects, provided that each planet branch carries a reasonable, preferably equal, share of the torque transmitted. In practice, the load shared among the planets is typically not equal due to the presence of various manufacturing errors. This study aims at enhancing the models for planet load sharing through a three-dimensional formulation of N-planet helical planetary gear sets. Apart from previous models, the proposed model employs a gear mesh load distribution model to capture load and time dependency of the gear meshes iteratively. It includes all three types of manufacturing errors, namely constant errors such as planet pinhole position errors and pinhole diameter errors, constant but assembly dependent errors such as nominal planet tooth thickness errors, planet bore diameter errors, and rotation and assembly dependent errors such as gear eccentricities and run-outs. At the end, the model is used to show combined influence of these errors on planet load sharing to aid designers on how to account for manufacturing tolerances in the design of the gears of a planetary gear set.

Development of High-Loaded, Low-Speed Spiroid Gearboxes

2000 ◽  
Author(s):  
V. I. Goldfarb ◽  
V. M. Spiridonov ◽  
N. S. Golubkov
Keyword(s):  
High Reliability ◽  
Operating Conditions ◽  
Design Parameters ◽  
Angular Range ◽  
Operating Modes ◽  
Gear Design ◽  
Gear Mesh ◽  
Numerical Studies ◽  
High Durability ◽  
Spiroid Gear

Abstract Actuator rotation sometimes is required to transmit considerable torques at low speeds in a limited angular range. Such operating conditions are typical, for example, for the rotational drives of gas pipeline stop valves. These conditions are made worse by increased torques requried at the initial instant of motion when the torque is 1.3 to 1.5 times greater than the nominal torque, and by the range of operating temperatures of −60°C to +50°C. A number of gearboxes with a spiroid gear mesh were developed to satisfy these conditions for different torques (i.e. for different standard stop valves), with the steel spiroid pair case-hardened to 60–62 hardness Rc. A set of numerical studies had been conducted in order to choose gear design parameters and other elements of the gearbox. Experimental research performed using special testing rigs for definite operating modes showed high reliability and wear resistance of the drives developed and their high durability compared to known ones which is of great importance for given application domain.

Oil Churning Power Losses of a Gear Pair: Experiments and Model Validation

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
S. Seetharaman ◽  
A. Kahraman ◽  
M. D. Moorhead ◽  
T. T. Petry-Johnson
Keyword(s):  
Power Loss ◽  
Spur Gear ◽  
Companion Paper ◽  
Design Parameters ◽  
Measured Parameter ◽  
Gear Pair ◽  
Power Losses ◽  
Gear Design ◽  
Face Width ◽  
Wide Range

This paper presents the results of an experimental study on load-independent (spin) power losses of spur gear pairs operating under dip-lubricated conditions. The experiments were performed over a wide range of operating speed, temperature, oil levels, and key gear design parameters to quantify their influence on spin power losses. The measurements indicate that the static oil level, rotational speed, and face width of gears have a significant impact on spin power losses compared with other parameters such as oil temperature, gear module, and the direction of gear rotation. A physics-based gear pair spin power loss formulation that was proposed in a companion paper (Seetharaman and Kahraman, 2009, “Load-Independent Spin Power Losses of a Spur Gear Pair: Model Formulation,” ASME J. Tribol., 131, p. 022201) was used to simulate these experiments. Direct comparisons between the model predictions and measurements are provided at the end to demonstrate that the model is capable of predicting the measured spin power loss values as well as the measured parameter sensitivities reasonably well.

A Load Distribution Model for Double-Planet Planetary Gear Sets

2019 ◽  
Author(s):  
Yong Hu ◽  
David Talbot ◽  
Ahmet Kahraman
Keyword(s):  
Load Distribution ◽  
Gear Tooth ◽  
Planetary Gear ◽  
System Level ◽  
Distribution Model ◽  
Ring Gear ◽  
Gear Mesh ◽  
Manufacturing Errors ◽  
Planetary Gear Sets ◽  
Bearing Stiffness

Abstract In this paper, a load distribution model for a double-planet planetary gear set is developed by modifying an existing single-planet planetary gear set model [1] to account for an additional planet to planet gear mesh and their impact on phasing relationship among different sun-planet, planet-planet and planet-ring gear meshes. Similar to the single-planet planetary gear set model, the double-planet planetary gear set model accounts for effects of various component and system level variations such as supporting conditions, gear tooth modifications, manufacturing errors and kinematic configurations. The double-planet planetary gear load distribution model is derived for both rigid and flexible ring gear rim, while only parametric studies for a rigid ring gear rim is presented in this paper to demonstrate load distribution characteristics of double-planet planetary gear sets with different planet bearing stiffness and combination of various types of manufacturing errors, including pin hole position error and runout errors.

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.

Analysis of flow regimes and associated sources of dissipation in splash lubricated planetary gear sets

2021 ◽  
pp. 1-22
Author(s):  
Jean-Baptiste Boni ◽  
Christophe Changenet ◽  
Fabrice Ville
Keyword(s):  
Planetary Gear ◽  
Operating Conditions ◽  
Centrifugal Forces ◽  
Power Losses ◽  
Planetary Gears ◽  
Compact Size ◽  
Depth Analysis ◽  
Planetary Gear Sets ◽  
High Reduction ◽  
Oil Characteristics

Abstract Planetary gears are used in several applications given that they provide high reduction ratio in a compact size. Two kind of lubrication are used in this applications: injection or splash lubrication. In case of splash lubrication, the authors already highlighted the importance of the centrifugal effects leading to the formation of an oil ring inside the reducer, therefore giving a method to compute churning power losses. In this paper, another flow regime is underlined when centrifugal forces are not sufficient to turn the oil sump into a ring. In addition to this observation, an in-depth analysis is given regarding the dependence of the churning power losses with operating conditions and oil characteristics.

Rapid optimal design of a multimode power split hybrid electric vehicle transmission

2018 ◽  
Vol 233 (3) ◽  
pp. 740-762 ◽  
Author(s):  
Pier Giuseppe Anselma ◽  
Yi Huo ◽  
Joel Roeleveld ◽  
Ali Emadi ◽  
Giovanni Belingardi
Keyword(s):  
Electric Vehicle ◽  
Fuel Economy ◽  
Hybrid Electric Vehicle ◽  
Design Methodology ◽  
Planetary Gear ◽  
Optimal Designs ◽  
Design Parameters ◽  
Power Split ◽  
Planetary Gear Sets ◽  
Hybrid Electric

This work aims at presenting a design methodology capable of modeling, generating, and testing a large number of multimode power split hybrid electric vehicle transmission designs in a relatively short period of time. Design parameters include the planetary gear ratios, the final drive ratio, the configuration of hookups to link the hybrid powertrain components to the planetary gear sets and the locations of clutch connections between different nodes of the planetary gear sets. The system modeling approach is first presented, including formulations for each component (the vehicle and road load, the engine, the motor/generators and the battery). A rapid and automated modeling procedure is proposed for hybrid electric vehicle transmissions including multiple planetary gear sets and clutch connections. Two algorithms are subsequently presented that enable fast evaluation of fuel economy and acceleration performance of hybrid electric vehicle transmission designs, namely the enhanced Power-Weighted Efficiency Analysis for Rapid Sizing and the Rapid Efficiency-based Launching Performance Analysis algorithms. The developed design methodology is tested by first modeling and evaluating three hybrid electric vehicle designs from the state-of-art. Later, an investigation for optimal designs that can ameliorate the examined benchmarks is performed. Several millions of design options are rapidly generated and tested using the proposed procedure. The methodology is proved effective by quickly coming up with two sub-optimal designs. Fuel economy and acceleration performance are improved by 5.56% and 40.56%, respectively, compared to the corresponding best benchmarks.

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