Influence of Planet Pin Stiffness on Load Sharing in Planetary Gear Drives

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Alfred N. Montestruc
Keyword(s):  
Planetary Gear ◽  
Load Sharing ◽  
Spring Constant ◽  
Spur Gears ◽  
The Finite Element Method ◽  
Specific Design ◽  
The Subject ◽  
Gear Drives ◽  
Gear Meshes ◽  
Spring Constants

Others have done significant work on the subject of load sharing among the planets of planetary gear drives; a brief review of that work is presented. Little work has been done, however, to evaluate the utility of the Hicks type flexible planet pins in improvement of load sharing in a planetary gear stage. This work shows the potential value of the three variations of the Hicks type flexible planet pin used on cantilever carriers, and a new design of a low spring constant planet pin that can be used on straddle type carriers. This is done by the calculation of the spring constants of gear meshes, bearings, and various designs of planet pins using the finite element method for a specific design of a planetary gear stage with spur gears and eight planets. The result showed significant differences. Low spring constant flexible pins are shown to have significantly superior load sharing characteristics.

A Numerical Approach to Calculation of Load Sharing in Planetary Gear Drives

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Alfred N. Montestruc
Keyword(s):  
Planetary Gear ◽  
Load Sharing ◽  
Numerical Approach ◽  
Design Tolerance ◽  
Epicyclic Gear ◽  
The Subject ◽  
Gear Drives ◽  
Relationship Of ◽  
Floating Systems ◽  
Exact Relationship

In AGMA 6123-B06 [2006, “Design Manual for Enclosed Epicyclic Gear Drives,” ANSI/AGMA Paper No. 6123-B06], a specific table is given for estimation of the planet load share factor Kγ, as it is termed in that publication; that table is vague as to the exact relationship of tolerance and load to the value of Kγ. Others have done significant works on the subject of load sharing among planets; a brief review of that work is presented. This work calculates a useful value of Kγ directly from design tolerance values and the torque applied to the carrier, and other factors showing how this can be done. This formulation is designed explicitly for nonfloating systems, but may be adaptable to floating systems. The use of flexible planet pins to improve load sharing is discussed. In addition, treating Kγ as a constant with respect to torque for a given planetary design is shown to be inaccurate.

Load Distribution in Timing Belts

1978 ◽  
Vol 100 (2) ◽  
pp. 208-215 ◽  
Author(s):  
G. Gerbert ◽  
H. Jo¨nsson ◽  
U. Persson ◽  
G. Stensson
Keyword(s):  
Load Distribution ◽  
Test Procedure ◽  
Spring Constant ◽  
The Finite Element Method ◽  
Belt Drives ◽  
Exponential Character ◽  
Timing Belt ◽  
Steel Cord ◽  
The Subject ◽  
Theory And Experiment

A theory is presented for determining the distribution of the belt tension and the tooth load in timing belts. It appears that the distribution of both loads is of exponential character and one important parameter is the ratio between the spring constant of the tooth and the spring constant of the cord (a nondimensional number). Friction between the belt and the top of the pulley is also considered. This mostly influences the tooth load distribution. A criterion is presented for maximum tension ratio with respect to correct tooth action. Two belts are examined experimentally (steel cord-urethane and glass fiber cord-neoprene rubber). The spring constant of the tooth is determined both experimentally (a test procedure is presented) and theoretically (using the finite element method) and the agreement is good. The distribution of the belt tension in timing belt drives has been measured. The agreement between theory and experiment for the belts examined is satisfactory. Some discrepancies were observed. These will be the subject for further research.

Use of the Integrated Flexpin Bearing for Improving the Performance of Epicyclical Gear Systems

2003 ◽  
Author(s):  
Gerald P. Fox ◽  
Eric Jallat
Keyword(s):  
Power Density ◽  
Planetary Gear ◽  
Load Sharing ◽  
Contact Patterns ◽  
Length Direction ◽  
Gear Systems ◽  
Planetary Gear System ◽  
Gear Contact ◽  
Gear Drives ◽  
Deflected State

Epicyclical gear systems have typically been equipped with straddle-mounted planetary idlers having pins supported on the input and output sides of the carrier. Torsional wind-up of the carrier, position accuracy of the pins, machining tolerances of the planetary gear system components and bearings clearances can all contribute to a poor load sharing among the planetary idlers as well as misaligned gear contacts in the deflected state. Use of the double-cantilevered flexible pin concept to achieve better load sharing and gear contact patterns among a multiplicity of planetary idlers, has been used to improve reliability in advanced gear drives for many years. The consequence of this practice is to build a compliant epicyclical system that improves power density in the gear length direction because the probability of achieving a properly centered gear contact is increased. The Integrated Flexpin Bearing, the subject of this paper, is capable of achieving additional power density in the gear diameter direction through integration of bearing components, gearing and shafting. This paper presents one designer’s approach to optimizing an Integrated Flexpin Bearing to improve the reliability of an epicyclical gearbox.

An Approach for Analysis of Load Sharing in Planetary Gear Drives With a Floating Sun Gear

2011 ◽  
Author(s):  
Shyi-Jeng Tsai ◽  
Siang-Yu Ye ◽  
Guan-Lin Huang
Keyword(s):  
Planetary Gear ◽  
Load Sharing ◽  
The Sun ◽  
Mesh Stiffness ◽  
Stiffness Model ◽  
Manufacturing Errors ◽  
Tooth Stiffness ◽  
Gear Geometry ◽  
Gear Drives ◽  
Acceptable Agreement

The goal of the paper is to propose an approach for analysis of load sharing in the planetary gear drives with a floating sun gear based on a stiffness model for multiple gear-pair contact under consideration of the mesh stiffness of the engaged teeth, as well as the tooth gaps due to manufacturing errors and deviated position of the sun gear. The tooth stiffness of gears is expressed analytically considering the bending deflection and the contact deformation. The relations for tooth gaps due to various errors are derived from the mesh relations of gears based on the exact involute gear geometry. The balanced position of the floating sun gear is solved iteratively by using the load equilibrium conditions and the shared loads at the corresponding position of the sun gear. Finally some numerical examples are illustrated. The results calculated by the proposed approach have, an acceptable agreement with those by using FEM.

Load Sharing Based Fillet Stress Analysis of Involute Helical Gears

2013 ◽  
Vol 465-466 ◽  
pp. 1234-1238
Author(s):  
R. Prabhu Sekar ◽  
G. Muthuveerappan
Keyword(s):  
Load Sharing ◽  
Accurate Estimation ◽  
The Finite Element Method ◽  
Helical Gears ◽  
Critical Loading ◽  
Face Width ◽  
Tooth Fracture ◽  
The Face ◽  
Gear Drives ◽  
Tip Radius

The tooth fracture occurs due to high fillet stress developed at the root fillet region along the face width, when the tooth is normally loaded. Hence, an accurate estimation of critical loading position on the tooth along the line of contact for maximum fillet stress and its location along the face width become important to reduce the tooth fracture. In the present work, the maximum fillet stress is evaluated based on load sharing ratio using the finite element method through the multi pair loaded model and using the results, the influence of cutter tip radius and addendum height on the load sharing ratio and respective maximum fillet stress is evaluated. The maximum fillet stress is lesser in the gear drives which is generated by the full round cutter and it increases due to increase the addendum height. The location at which the maximum fillet stress occurs along the face width is determined, when the load is applied at the critical loading position in the helical gear drive.

scholarly journals Design of Electrically Powered Morphing Winglet

2021 ◽  
Author(s):  
Kunj Mistry
Keyword(s):  
Material Selection ◽  
Gear Tooth ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Stepper Motor ◽  
Spur Gears ◽  
Input Shaft ◽  
Gear Drive ◽  
Electrical Actuator ◽  
Gear Drives

Cycloidal and planetary gear drives are considered for the actuation of an electrically powered morphing winglet. A torque of 6723 N*m is required at the winglet hinge. The stepper motor selected as the electrical actuator is the HT34-487 stepper motor. This motor can provide a torque of approximately 6 N*m. The cycloidal drive consists of the selected stepper motor, a bevel gearbox, and a two-stage cycloidal gearbox. The bevel gearbox is used to change the axis of rotation of the stepper motor from span-wise direction to chord-wise direction. Stage one of the cycloidal gearbox contains an input shaft, two cycloidal disks with 180 degrees offset rotation, an eccentric cam and an output shaft. The cycloidal disks in stage one have 35 lobes, providing a gear ratio of 35:1. The second stage of the cycloidal gearbox consists of only one cycloidal disk with 34 lobes, providing a gear ratio of 34:1. The total gear ratio of the cycloidal drive is 1190:1. Material selection and FEA simulations are performed on the components in the cycloidal drive to ensure the selected materials can withstand the applied loads. A differential planetary gear drive is also considered to actuate an electrically powered morphing winglet. Spur gears are selected to be used as the sun and planet gears. A ratio of 180:1 is achieved in the planetary gear drive. Using gear tooth bending calculators, it is found that designing spur gears to withstand the loads of the electrically powered morphing winglet and to fit inside the dimensions of the wingbox is not feasible.

scholarly journals Design of Electrically Powered Morphing Winglet

2021 ◽  
Author(s):  
Kunj Mistry
Keyword(s):  
Material Selection ◽  
Gear Tooth ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Stepper Motor ◽  
Spur Gears ◽  
Input Shaft ◽  
Gear Drive ◽  
Electrical Actuator ◽  
Gear Drives

Cycloidal and planetary gear drives are considered for the actuation of an electrically powered morphing winglet. A torque of 6723 N*m is required at the winglet hinge. The stepper motor selected as the electrical actuator is the HT34-487 stepper motor. This motor can provide a torque of approximately 6 N*m. The cycloidal drive consists of the selected stepper motor, a bevel gearbox, and a two-stage cycloidal gearbox. The bevel gearbox is used to change the axis of rotation of the stepper motor from span-wise direction to chord-wise direction. Stage one of the cycloidal gearbox contains an input shaft, two cycloidal disks with 180 degrees offset rotation, an eccentric cam and an output shaft. The cycloidal disks in stage one have 35 lobes, providing a gear ratio of 35:1. The second stage of the cycloidal gearbox consists of only one cycloidal disk with 34 lobes, providing a gear ratio of 34:1. The total gear ratio of the cycloidal drive is 1190:1. Material selection and FEA simulations are performed on the components in the cycloidal drive to ensure the selected materials can withstand the applied loads. A differential planetary gear drive is also considered to actuate an electrically powered morphing winglet. Spur gears are selected to be used as the sun and planet gears. A ratio of 180:1 is achieved in the planetary gear drive. Using gear tooth bending calculators, it is found that designing spur gears to withstand the loads of the electrically powered morphing winglet and to fit inside the dimensions of the wingbox is not feasible.

Numerical and Experimental Analysis of Flexible Pin Mechanisms for Load Balancing in Planetary Gear Drives

2013 ◽  
Author(s):  
Hsiang-Yu Yeh ◽  
Shyi-Jeng Tsai ◽  
Yuan-Yi Yu
Keyword(s):  
Numerical Analysis ◽  
Load Balancing ◽  
Experimental Analysis ◽  
Planetary Gear ◽  
Load Sharing ◽  
Design Parameters ◽  
Sufficient Information ◽  
Gear Drives ◽  
Important Design ◽  
Novel Design

Load balancing mechanism is an important design for planetary gear drives. Among the well-known designs the flexible pin mechanism has advantage for even load sharing among more than three planet gears. However, there is no sufficient information about how to design such mechanisms. The goal of the paper is to propose an analysis approach of flexible pin mechanisms for planetary gear drives numerically and experimentally. Two types of flexible pin mechanisms are analyzed in the study, a conventional design and a novel design. Numerical analysis is carried out by software KISSsoft and FEM to evaluate the influence of the design parameters of flexible pin mechanism on the deformation performance. An experiment was finally conducted to verify the analysis results.

scholarly journals Simulative investigation of ring creep on a planetary bearing of a wind turbine gearbox

2021 ◽  
Author(s):  
Jonas Gnauert ◽  
Felix Schlüter ◽  
Georg Jacobs ◽  
Dennis Bosse ◽  
Stefan Witter
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Sensitivity Analysis ◽  
Planetary Gear ◽  
The Finite Element Method ◽  
Relative Movement ◽  
Wind Turbine Gearbox ◽  
Interference Fit ◽  
Planetary Gears ◽  
Module Coefficient

AbstractWind turbines (WT) must be further optimized concerning availability and reliability. One of the major reasons of WT downtime is the failure of gearbox bearings. Some of these failures occur, due to the ring creep phenomenon, which is mostly detected in the planetary bearings. The ring creep phenomenon describes a relative movement of the outer ring to the planetary gear. In order to improve the understanding of ring creep, the finite element method (FEM) is used to simulate ring creep in planetary gears. First, a sensitivity analysis is carried out on a small bearing size (NU205), to characterize relevant influence parameters for ring creep—considered parameters are teeth module, coefficient of friction, interference fit and normal tooth forces. Secondly, a full-scale planetary bearing (SL185030) of a 1MW WT is simulated and verified with experimental data.

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