Meshing Efficiency of Involute Helical Gears Based on Elastohydrodynamic Lubrication

2014 ◽  
Vol 597 ◽  
pp. 450-453
Author(s):  
Bin Wang ◽  
Xin Bo Chen
Keyword(s):  
Load Distribution ◽  
Integration Method ◽  
Elastohydrodynamic Lubrication ◽  
Helical Gear ◽  
Dynamic Efficiency ◽  
Unit Load ◽  
Helical Gears ◽  
Double Integration ◽  
Simulation Results ◽  
Meshing Process

To analyze the dynamic efficiency of helical gear during meshing process, a meshing efficiency model based on elastohydrodynamic lubrication (EHL) was established. The meshing plane between the pinion and gear was divided into seven parts in accordance to the regularity of unit load distribution. The total meshing power lose and average meshing power lose were calculated through a double integration method. The simulation results show that the method is feasible to calculate the meshing efficiency of gear pairs.

Solution of Load Distribution on the Contact Line of Helical Gears With EHL Theory

1994 ◽  
Author(s):  
Yu Tonghui ◽  
Chen Chenwen ◽  
Wang Liqin
Keyword(s):  
Contact Line ◽  
Load Distribution ◽  
Multigrid Method ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Helical Gear ◽  
Contact Lines ◽  
Helical Gears ◽  
Special Boundary Condition

Abstract On the base of analysis of the effects of each term in Renolds equaiton on the lubrication state of helical gears, the three dimensional elastohydrodynamic lubrication (EHL) problem is discomposed into two dimensional problems to deal with. A special boundary condition for helical gear EHL problem is led in and applying multigrid method (MGM), numerical solutions for the helical gear EHL problem are accomplished along the contact line. Film shapes and pressure ditributions with typical EHL features are obtained at discreted points on the contact line. The procedure presented here to calculate the load distribution on the contact line can also be used to calculate the load shares among different contact lines.

An Experimental and Theoretical Study of Quasi-Static Behavior of Double-Helical Gear Sets

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
M.R. Kang ◽  
A. Kahraman
Keyword(s):  
Load Distribution ◽  
Theoretical Study ◽  
Power Transmission ◽  
Transmission Error ◽  
Helical Gear ◽  
Static Behavior ◽  
World Congress ◽  
Helical Gears ◽  
Support Conditions ◽  
Stagger Angle

Abstract The quasi-static behaviors of a double-helical gear pair is investigated both experimentally and theoretically with the main focus on the influence of the key design and manufacturing parameters associated with double-helical gears, including nominal right-to-left stagger angle, the stagger angle deviation (error) from the nominal stagger angle, and axial gear supporting conditions. On the experimental side, a double-helical gear test setup proposed earlier (Kang, M. R., and Kahraman, A., 2015, “An Experimental and Theoretical Study of Dynamic Behavior of Double-Helical Gear Sets,” J. Sound Vib., 350, pp. 11–29). for studying dynamics of the same system is employed that allows adjustable right-to-left stagger angles, intentional stagger errors, and axial support conditions. Specific measurement systems are developed and implemented simultaneously to measure the static motion transmission error and axial motions of the gears under low-speed conditions, as well as gear root strains to determine right-to-left load-sharing factors. A test matrix that covers wide ranges of stagger angles, intentional stagger error, and axial support conditions is executed within a range of torque transmitted to establish an extensive database. On the modeling side, the measured quasi-static behavior of double-helical gear pairs is simulated by using an existing quasi-static double-helical load distribution model (Thomas, J., and Houser, D. R., 1992, “A Procedure for Predicting the Load Distribution and Transmission Error Characteristics of Double Helical Gears,” World Congress-Gear and Power Transmission, The 3rd World Congress—Gear and Power Transmission, Paris.). Direct comparison of the measurements and predictions of loaded static transmission error, axial play, root stresses, and right-to-left load-sharing factors are used to validate the quasi-static model as well as describing the measured behavior.

Analysis of Plastic Helical Gear

2006 ◽  
Author(s):  
Toni Jabbour ◽  
Ghazi Asmar ◽  
Chadi Ghaith
Keyword(s):  
Mathematical Model ◽  
Real Number ◽  
Modulus Of Elasticity ◽  
Load Distribution ◽  
Large Deformations ◽  
Tooth Wear ◽  
Helical Gear ◽  
Contact Ratio ◽  
Helical Gears ◽  
The Real

The objective of this work is to present a mathematical model which studies helical gears made of a material with a small modulus of elasticity, when one or more pairs of teeth mesh prematurely during engagement. This phenomenon may lead to the modification of the load distribution on the teeth which are initially in contact and to a kind of interference causing additional tooth wear of the gear. In this case, the calculation of the contact ratio must account for the real number of pairs of teeth in contact. This is especially important when large deformations occur as is confirmed in the results presented to confirm the validity of the proposed method.

Modeling of dynamic efficiency of curve–face gear pairs

2015 ◽  
Vol 230 (7-8) ◽  
pp. 1209-1221 ◽  
Author(s):  
Chao Lin ◽  
Zhiqin Cai
Keyword(s):  
Load Distribution ◽  
Elastohydrodynamic Lubrication ◽  
Dynamic Efficiency ◽  
Power Losses ◽  
Key Factors ◽  
Face Gear ◽  
Force Coefficient ◽  
Static Efficiency ◽  
Pitch Curve ◽  
Curve Face

The characteristics and the tooth distribution regularity of curve–face gear were analyzed based on the elastohydrodynamic lubrication. Then a model for the prediction of mechanical dynamic efficiency of curve–face gear was presented by the concentrated parameters, including dynamic-loading tooth force, coefficient, the oil film thickness, the space relative velocity and load distribution. The discretization method was introduced to solve the computational formulas of key factors above. A meshing period defined from trough (enter meshing point) to peak (outer meshing point) of the pitch curve and the tooth profile was discreted into some parts for calculation of the sliding and the rolling power losses. The dynamic and static efficiency of curve–face gear were analyzed, and the results of simulation and test were similar during the corresponding time, which verified the correctness of theoretical model.

scholarly journals Robustness of Cyber-Physical Supply Networks in Cascading Failures

Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 769
Author(s):  
Dong Mu ◽  
Xiongping Yue ◽  
Huanyu Ren
Keyword(s):  
Load Distribution ◽  
Cascading Failure ◽  
Cascading Failures ◽  
Supply Network ◽  
Supply Networks ◽  
Defense Strategies ◽  
Critical Thresholds ◽  
Network Load ◽  
Physical Node ◽  
Simulation Results

A cyber-physical supply network is composed of an undirected cyber supply network and a directed physical supply network. Such interdependence among firms increases efficiency but creates more vulnerabilities. The adverse effects of any failure can be amplified and propagated throughout the network. This paper aimed at investigating the robustness of the cyber-physical supply network against cascading failures. Considering that the cascading failure is triggered by overloading in the cyber supply network and is provoked by underload in the physical supply network, a realistic cascading model for cyber-physical supply networks is proposed. We conducted a numerical simulation under cyber node and physical node failure with varying parameters. The simulation results demonstrated that there are critical thresholds for both firm’s capacities, which can determine whether capacity expansion is helpful; there is also a cascade window for network load distribution, which can determine the cascading failures occurrence and scale. Our work may be beneficial for developing cascade control and defense strategies in cyber-physical supply networks.

Gear transmission error outside the normal path of contact due to corner and top contact

1999 ◽  
Vol 213 (4) ◽  
pp. 389-400 ◽  
Author(s):  
R. G. Munro ◽  
L Morrish ◽  
D Palmer
Keyword(s):  
Dynamic Test ◽  
Theoretical Models ◽  
Transmission Error ◽  
Helical Gear ◽  
Gear Transmission ◽  
The Novel ◽  
Transmission Systems ◽  
Helical Gears ◽  
Tooth Stiffness ◽  
Top Contact

This paper is devoted to a phenomenon known as corner contact, or contact outside the normal path of contact, which can occur in spur and helical gear transmission systems under certain conditions. In this case, a change in position of the driven gear with respect to its theoretical position takes place, thus inducing a transmission error referred to here as the transmission error outside the normal path of contact (TEo.p.c). The paper deals with spur gears only, but the results are directly applicable to helical gears. It systematizes previous knowledge on this subject, suggests some further developments of the theory and introduces the novel phenomenon of top contact. The theoretical results are compared with experimental measurements using a single flank tester and a back-to-back dynamic test rig for spur and helical gears, and they are in good agreement. Convenient approximate equations for calculation of TEo.p.c suggested here are important for analysis of experimental data collected in the form of Harris maps. This will make possible the calculation of tooth stiffness values needed for use in theoretical models for spur and helical gear transmission systems.

scholarly journals Optimal design of high efficiency double helical gear based on dynamics model

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Fengxia Lu ◽  
Xuechen Cao ◽  
Weiping Liu
Keyword(s):  
Dynamic Model ◽  
High Efficiency ◽  
Bending Strength ◽  
Sliding Friction ◽  
Elastohydrodynamic Lubrication ◽  
Optimization Method ◽  
Transmission Efficiency ◽  
Helical Gear ◽  
Transmission System ◽  
Vibration Displacement

AbstractA 16-degree-of-freedom dynamic model for the load contact analysis of a double helical gear considering sliding friction is established. The dynamic equation is solved by the Runge–Kutta method to obtain the vibration displacement. The method combines the friction coefficient model based on the elastohydrodynamic lubrication theory with the dynamic model, which provides a theoretical basis for the calculation of the power loss of the transmission system. Moreover, the sensitivity analysis of the parameters that affect the transmission efficiency is carried out, and an optimization method of meshing efficiency is proposed without reducing the bending strength of the gears. This method can directly guide the design of the double helical gear transmission system.

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