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.

Research on Dynamic Model of Double Helical Gear Pair Based on TCA and LTCA

2019 ◽  
Vol 24 (3) ◽  
pp. 476-484 ◽  
Author(s):  
Cheng Wang ◽  
Shouren Wang ◽  
Gaoqi Wang
Keyword(s):  
Friction Coefficient ◽  
Dynamic Model ◽  
Dynamic Models ◽  
Sliding Friction ◽  
Helical Gear ◽  
Tooth Surface ◽  
Gear Pair ◽  
Axial Vibration ◽  
Sliding Friction Coefficient ◽  
Helical Gear Pair

Numerous dynamic models of spur gears, helical gears, bevel gears, and face gears can be found in various studies. However, studies that focus on the dynamic model of a double helical gear pair are quite limited. The author proposed a model of a double helical gear pair by only considering the axial vibration. The author did not consider the friction and multiple backlashes in the proposed model. The friction force of the tooth surface and backlash are important factors that can cause complex non-linear phenomena in gear pairs. Therefore, a dynamic model of a double helical gear pair that takes into consideration the axial vibration, friction and multiple backlashes is proposed. Firstly, based on the tooth contact analysis (TCA) of a double helical gear pair, the path of contact and meshing time from engagement to disengagement are obtained. The formula for determining the sliding friction coefficient is introduced. Based on TCA and the dynamic meshing force provided by the subsequent dynamics model of double helical gear pair, the sliding friction coefficient of the tooth surface is calculated. Secondly, the stiffness excitation, gear-into impact excitation and error excitation (including the axial displacement caused by the errors of manufacture and installation under low speed) are calculated according to the existing research results. Following this, a dynamic model of a double helical gear pair that takes into consideration the axial vibration, friction and multiple backlashes is both built and solved. Finally, an example is presented to verify the corresponding results.

Dynamic model of a helical gear pair considering tooth surface friction

2020 ◽  
Vol 26 (15-16) ◽  
pp. 1356-1366 ◽  
Author(s):  
Cheng Wang
Keyword(s):  
Friction Coefficient ◽  
Dynamic Model ◽  
Sliding Friction ◽  
Surface Friction ◽  
Helical Gear ◽  
Tooth Surface ◽  
Gear Pair ◽  
Tooth Contact Analysis ◽  
Sliding Friction Coefficient ◽  
Helical Gear Pair

The tooth surface friction is one of the main sources of gear vibration and noise. The current challenging problems in research of a helical gear pair dynamics considering tooth surface friction include the following: (1) Calculation accuracy of the tooth surface friction factor needs to be improved. (2) The meshing process of a helical gear pair has not been fully taken into account in a dynamic model. To solve these problems, a dynamic model of a helical gear pair considering tooth surface friction is proposed in this article. First, based on the tooth contact analysis and loaded tooth contact analysis of a helical gear pair, excitation of time-varying meshing stiffness, the sliding friction coefficient on tooth surface, and the arm of friction force are preliminarily calculated. Second, the dynamic model of a helical gear pair considering tooth surface friction is built and solved, in which the dynamic meshing force/speed/displacement is calculated. The sliding friction coefficient on tooth surface, arm of friction force, and dynamic equations form a coupled system. By decoupling calculation, the model system equations are solved. Finally, an example is presented to verify the proposed model.

scholarly journals Efficiency Estimation of Roller Chain Power Transmission System

2020 ◽  
Vol 10 (21) ◽  
pp. 7729
Author(s):  
Sheng-Peng Zhang ◽  
Tae-Oh Tak
Keyword(s):  
Sliding Friction ◽  
Power Transmission ◽  
Transmission Efficiency ◽  
Transmission System ◽  
Damping Coefficient ◽  
Damping Force ◽  
Roller Chain ◽  
Power Transmission System ◽  
Novel Approach ◽  
Efficiency Estimation

In the present study, a novel approach to estimating the efficiency of roller chain power transmission systems is proposed based on sliding friction losses and damping force. The dynamics model is taken into account between chain links with lateral offset owing to the derailleur system. Frictional losses were calculated according to Coulomb’s law of friction, and the damping force was dependent on the damping coefficient. The effects of rotational speed, load, derailleur system, and damping coefficient on transmission efficiency were analyzed. The test stand of the roller chain power transmission system was set up to verify the estimated efficiency, and the results showed a good correlation, demonstrating the validity of the chain power transmission efficiency estimation.

A calculation method of sliding friction coefficient on tooth surface for helical gear pair based on loaded tooth contact analysis and elastohydrodynamic lubrication theory

2020 ◽  
pp. 135065012096689
Author(s):  
Cheng Wang ◽  
Mao Ken
Keyword(s):  
Friction Coefficient ◽  
Sliding Friction ◽  
Elastohydrodynamic Lubrication ◽  
Helical Gear ◽  
Tooth Surface ◽  
Gear Pair ◽  
Tooth Contact Analysis ◽  
Sliding Friction Coefficient ◽  
Loaded Tooth Contact Analysis ◽  
Helical Gear Pair

The sliding friction coefficient on tooth surface is related to power loss, carry capacity and transmission performance of gear. Reasonable transmission analysis of gear pair is the premise of accurate calculation of sliding friction coefficient on tooth surface. However, for helical gear pair, the line contact without considering machining error/installation error/modification of gear is usually adopted to replace the major axis of ellipse caused by contact load. Therefore, in this paper, contact path on tooth surface, length of contact line, load distribution on tooth surface and loaded transmission errors are accurately calculated by loaded tooth contact analysis (LTCA). Combing with elastohydrodynamic lubrication (EHL) theory, a calculation method of sliding friction coefficient on tooth surface for helical gear pair is proposed.

High-efficiency and compact WPT receiving antenna design using simulation optimization method

2021 ◽  
pp. 002072092198901
Author(s):  
Yanghyun Kim ◽  
Chulhun Seo
Keyword(s):  
Machine Learning ◽  
High Efficiency ◽  
Optimization Method ◽  
Transmission Efficiency ◽  
Learning Technology ◽  
Q Factor ◽  
Power Transfer ◽  
Wireless Power ◽  
High Q ◽  
Receiving Antenna

In this paper, a high-efficiency and compact wireless power transfer (WPT) receiving antenna using an flexible printed circuits board (FPCB) with high-Q factor is proposed. The proposed high-efficiency and compact WPT receiving antenna consists of a spiral structure, a lumped element and via through the ground structure. In this paper, in order to design a miniaturized high-efficiency WPT receiving antenna, machine learning technology was used to optimally design the antenna pattern that affects the Q factor. The designed receiving antenna has improved wireless power transmission efficiency with high Q characteristics. The power transfer efficiency is above 88% from distance 10 mm and the resonant frequency is 110 MHz. The sizes of the receiving antenna and the NFC antenna are 30 × 40 mm and 20 × 30 mm, respectively. Machine learning was used to design and fabricate the composite module of a WPT receiving antenna and NFC antenna. Comparison of the experimental results of the proposed receiving antenna with a general receiving antenna confirms the improvement in transmission efficiency.

Mechanical Power Losses of Ball Bearings: Model and Experimental Validation

2021 ◽  
pp. 1-29
Author(s):  
Ahmet Dindar ◽  
Amit Chimanpure ◽  
Ahmet Kahraman
Keyword(s):  
Dynamic Model ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Mechanical Power ◽  
Ball Bearings ◽  
Power Losses ◽  
Euler Parameters ◽  
Surface Shear ◽  
Axial Forces ◽  
Set Up

Abstract A tribo-dynamic model of ball bearings is proposed to predict their load-dependent (mechanical) power losses. The model combines (i) a transient, point contact mixed elastohydrodynamic lubrication (EHL) formulation to simulate the mechanics of the load carrying lubricated ball-race interfaces, and (ii) a singularity-free dynamics model, and establishes the two-way coupling between them that dictates power losses. The dynamic model employs a vectoral formulation with Euler parameters. The EHL model is capable of capturing two-dimensional contact kinematics, velocity variations across the contact as well as asperity interactions of rough contact surfaces. Resultant contact surface shear distributions are processed to predict mechanical power losses of example ball bearings operating under combined radial and axial forces. An experimental set-up is introduced for measurement of the power losses of rolling-element bearings. Sets of measurements taken by using the same example ball bearings are compared to those predicted by the model to assess its accuracy in predicting mechanical power loss of a ball bearing within wide ranges of axial and radial forces.

scholarly journals Improved Experimental Procedures for Achieving Efficient Germ Line Transmission of Nonobese Diabetic (NOD)-Derived Embryonic Stem Cells

2004 ◽  
Vol 5 (3) ◽  
pp. 219-226 ◽  
Author(s):  
Satoko Arai ◽  
Christina Minjares ◽  
Seiho Nagafuchi ◽  
Toru Miyazaki
Keyword(s):  
High Efficiency ◽  
Germ Line ◽  
Gene Knockout ◽  
Es Cells ◽  
Embryonic Stem ◽  
Nod Mice ◽  
Insulin Dependent Diabetes Mellitus ◽  
Transmission Efficiency ◽  
Dependent Diabetes Mellitus ◽  
Specific Gene

The manipulation of a specific gene in NOD mice, the best animal model for insulin-dependent diabetes mellitus (IDDM), must allow for the precise characterization of the functional involvement of its encoded molecule in the pathogenesis of the disease. Although this has been attempted by the cross-breeding of NOD mice with many gene knockout mice originally created on the 129 or C57BL/6 strain background, the interpretation of the resulting phenotype(s) has often been confusing due to the possibility of a known or unknown disease susceptibility locus (e.g.,Iddlocus) cosegregating with the targeted gene from the diabetes-resistant strain. Therefore, it is important to generate mutant mice on a pure NOD background by using NOD-derived embryonic stem (ES) cells. By using the NOD ES cell line established by Nagafuchi and colleagues in 1999 (FEBSLett., 455, 101–104), the authors reexamined various conditions in the context of cell culture, DNA transfection, and blastocyst injection, and achieved a markedly improved transmission efficiency of these NOD ES cells into the mouse germ line. These modifications will enable gene targeting on a “pure” NOD background with high efficiency, and contribute to clarifying the physiological roles of a variety of genes in the disease course of IDDM.

scholarly journals Operating Performance of Power Systems Integrated HVDC Solution: KonTum-GiaLai Transmission System Case Considering Penetration of Renewable Energy

2020 ◽  
Vol 18 (4.2) ◽  
pp. 32
Author(s):  
Kim Hung Le ◽  
Ngoc Thien Nam Tran ◽  
Viet Tri Nguyen ◽  
The Khanh Truong ◽  
Minh Quan Duong
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
High Voltage ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Transmission Efficiency ◽  
Transmission System ◽  
Large Power ◽  
Hvdc System ◽  
Hvdc Transmission

The increasing demand for electricity along with the development of distributed generators showed that improving transmission efficiency and reliability is an indispensable requirement in the operation of the power system. Advanced technologies need to be applied to modern power systems for purposes of conveying large power flows, mitigating the risk of faults. High-voltage direct current (HVDC) transmission is now considered an effective solution for investment in large-length power lines, replacing the conventional high-voltage alternative current (HVAC) transmission system, especially in period of increasing generation capacity due to the penetration of renewable energy sources. This study assesses the performance of the HVDC system on an actual power grid based on planning and improvement demands. The calculation results of power flows, power losses and short-circuit faults were investigated using ETAP software X  

Sign in / Sign up

Export Citation Format

Share Document