Power Analysis and Efficiency Calculation of the Complex and Closed Planetary Gears Transmission

Li, Jianying; Hu, Qingchun

doi:10.1016/j.egypro.2016.10.197

Cited by 18 publications

(8 citation statements)

References 10 publications

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“…in which W s−SP and W s−PR are calculated separately, by using Eqns. ( 1) to (8). e average power lost through friction will be equal to the total friction energy losses divided by the time corresponding to one meshing cycle:…”

Section: Analysis Of the Friction Power Lossesmentioning

confidence: 99%

“…Owing to the high gear ratio and power density required by a wind turbine, the gearbox is commonly based on planetary gear sets, primarily for the first stages [4]. Although power losses in planetary gears have recently become a topic of interest for some researchers [4][5][6][7][8][9], there is significantly more technical literature available related to power losses in parallel axis cylindrical gears [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. e study of the various different components of the power losses in gearboxes [4,11,12,[25][26][27] and the determination of the friction coefficient [13,24,[28][29][30][31] have also been of interest to researchers.…”

Section: Introductionmentioning

confidence: 99%

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Minimum Friction Losses in Planetary Stages of Wind Turbine Gearboxes

Pedrero

Sánchez

Guerra

et al. 2022

Mathematical Problems in Engineering

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Mechanical efficiency is not a critical design factor of wind turbine gearboxes since wind energy is abundant and costless. The design and sizing of the gears will be determined by the requirements of power density, gear ratio, fatigue safety, and allowable noise and vibration levels. However, reducing power losses results in lower lubricant heating, and therefore, a smaller cooling system is required with lower induced thermal stresses. Reducing friction losses will therefore be beneficial for the mechanical behavior of the gearbox. This paper provides a new method for the calculation of the optimal values of the outside radii and rack shift coefficients of planetary gear stages to minimize the friction power losses, maintaining unalterable geometrical and operating parameters that ensure the preestablished values of the aforementioned critical design factors.

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Section: Analysis Of the Friction Power Lossesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Minimum Friction Losses in Planetary Stages of Wind Turbine Gearboxes

Pedrero

Sánchez

Guerra

et al. 2022

Mathematical Problems in Engineering

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“…But owing to the specific operating conditions of the wind turbine gearboxes it is not appropriate to improve the mechanical efficiency at expense of worsen the teeth strengths or load carrying capacities. In consequence, results of the mentioned studies [11][12][13][14][15] are not entirely applicable to win turbines. In this paper, a new optimization method of the mechanical losses in wind turbine gearboxes, regarding the design parameters to ensure the desired operating conditions, is presented.…”

Section: Introductionmentioning

confidence: 98%

“…But due to the high gear ratio and high power-density required by the wind turbine, gearboxes based on planetary gear sets are commonly used [11]. Literature on power loss of planetary gears are scarcer, although it has been of interest to some researchers [11][12][13][14][15]. The work of Nutakor et al [11] is specifically focused on the power loss modelling of windturbines two stage planetary gear sets, and includes a parametric study on the influence of various design parameters, as the carriers speed, face width, module, pressure angle, and helix angle.…”

Section: Introductionmentioning

confidence: 99%

Minimum friction losses in wind turbine gearboxes

Pedrero

Martínez-López

Calvo-Irisarri

et al. 2021

Forsch Ingenieurwes

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Improving the mechanical efficiency is not the most important objective in the design of wind turbine gearboxes since the available wind energy is abundant and costless. The most important criteria for dimensioning the gearbox are the fatigue strength—bending and pitting—, noise emission, vibrations, and maintenance requirements. Nevertheless, mechanical losses increase the lubricant temperature and induce thermal stresses, which increases wear and cracking risk. This means that friction losses should be reduced as much as possible, but always regarding the contact and tooth-root stress levels, as well as the other operating parameters which should be kept for ensuring the required operating conditions.In this paper, a study on the variation of the friction losses with the tooth shift coefficients is presented. All the other geometrical parameters—number of teeth, tooth height, pressure angle, helix angle, face width, and center distance—are unalterable, since all of them have been chosen according to more important design requirements. In addition, to keep the contact and tooth-root stress levels, the shift coefficients of the sun, planets and ring are calculated in such a way that the transverse contact ratios are kept, and therefore the critical load points for bending and pitting are also unchanged. The radial clearance is also kept in order to allow the proper evacuation of the lubricant. Finally, all the geometrical constraints (undercut, pointing, root interference, secondary interference, backlash) are also imposed. With all these restrictions, the optimal shift coefficients for all the gears are calculated to minimize the friction losses.

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“…Its capability of managing power flows from different sources is of paramount importance for energy saving. For these reasons, the mechanical efficiency of planetary multi degrees-offreedom planetary gear trains is a topic that received many contributions in recent times (e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14]).…”

Section: Introductionmentioning

confidence: 99%

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

2021

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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.

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Power Analysis and Efficiency Calculation of the Complex and Closed Planetary Gears Transmission

Cited by 18 publications

References 10 publications

Minimum Friction Losses in Planetary Stages of Wind Turbine Gearboxes

Minimum Friction Losses in Planetary Stages of Wind Turbine Gearboxes

Minimum friction losses in wind turbine gearboxes

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

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