scholarly journals Influence of Different Modified Gears on the Vibration and Noise of Electric Vehicle Reducer

2021 ◽  
Vol 26 (4) ◽  
pp. 325-336
Author(s):  
Bo Xu ◽  
Yu Qiu ◽  
Bifeng Yin ◽  
Xijun Hua ◽  
Hang Du
Keyword(s):  
Electric Vehicle ◽  
Great Influence ◽  
Coupling Model ◽  
Contact Spot ◽  
Tooth Profile ◽  
Time Varying ◽  
Meshing Stiffness ◽  
Simulating Calculation ◽  
Before And After ◽  
Gear Contact

The tooth profile crowning modification was applied onto paired gears for reducing the noise of an electric vehicle reducer. The simulated gear contact spots are compared before and after modification, and are validated by a contact spot experiment. Based on the rigid-flexible coupling model of the gear transmission system, the time-varying meshing stiffness, time-varying meshing force, and the vibration and noise of the gear pairs with different modified gears obtained by simulating calculation are analyzed. The results showed that the selection of modified gear has a great influence on the modification effect. In the way of tooth profile crowning, it is not advisable to modify the pinion independently, as it may increase the frequency and degree of meshing impact between the helical gear pair, making the transmission become less smooth; while modifying the wheel and pinion at the same time can effectively reduce the time-varying meshing stiffness and force, and the vibration and noise. Also, the optimized gear modification scheme is verified by the noise test.

Dynamic Simulation of 2K-H Differential Gear Train with Time-Varying Meshing Stiffness

2011 ◽  
Vol 314-316 ◽  
pp. 1603-1606
Author(s):  
Ying Chen Ma ◽  
Yan Wang ◽  
Ji Sheng Ma ◽  
Hai Ping Liu
Keyword(s):  
Life Prediction ◽  
Theoretical Data ◽  
Gear System ◽  
Gear Train ◽  
Time Varying ◽  
Meshing Stiffness ◽  
Torsion Vibration ◽  
Differential Gear ◽  
Gear Contact ◽  
Object Dynamic

Taking 2K-H differential gear train as study object, dynamic equation of torsion vibration was established with influence of time-varying meshing stiffness. The virtual-prototype with nonlinear meshing force was modeled using Virtual.Lab Motion software. Gear contact force was simulated, and it was verified by theoretical data. The reason of meshing vibration is analyzed. The results show that time-varying meshing stiffness is the main excitation of gear system, and gear system is vibratory although the input and output are stable, and the basic frequency is meshing frequency. This research lays foundation for strength checking, optimum design and fatigue life prediction.

scholarly journals Analysis of the characteristics of electromechanical-hydraulic model of multi-source drive/transmission system based on periodic excitation

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401881712
Author(s):  
Yang Yang ◽  
Yuquan Mi ◽  
Datong Qin ◽  
Aihui Yuan ◽  
Guowei Li
Keyword(s):  
Dynamic Characteristics ◽  
Coupling Model ◽  
Flow Speed ◽  
Transmission System ◽  
Drive System ◽  
Lumped Parameter Model ◽  
Time Varying ◽  
Flow Pulsation ◽  
Meshing Stiffness ◽  
Internal Excitation

Multi-source drive system with the feature of compact, small size and other advantages is widely used in large engineering machinery, such as shield machine, wind turbines, and shearer. In this article, a reasonable power transmission form is designed and the electromechanical-hydraulic coupling model of the multi-source drive system including the hydraulic pump-motor lumped parameter model and gear system dynamics model is established based on the co-simulation of MATLAB and AMEsim. Taking the pump flow pulsation and the time-varying meshing stiffness as the external and internal excitation of the multi-source drive system, respectively, the vibration and the dynamic characteristics of the multi-source drive system and the transfer characteristics of the dynamic excitation are analyzed. Results show that the flow-speed pulsation and the pressure-torque pulsation are gradually reduced along the direction of the transmission chain. As the external and internal excitation, the flow pulsation and the time-varying meshing stiffness will cause complex influences on the vibration and the dynamic characteristics of the multi-source transmission system. The findings provide a reference basis for the design of the multi-source drive system.

Research on dynamic characteristics of gear system considering the influence of temperature on material performance

2021 ◽  
pp. 107754632110026
Author(s):  
Zhou Sun ◽  
Siyu Chen ◽  
Xuan Tao ◽  
Zehua Hu
Keyword(s):  
Elastic Modulus ◽  
Dynamic Characteristics ◽  
Poisson’S Ratio ◽  
Gear System ◽  
Poisson's Ratio ◽  
Effect Of Temperature ◽  
Time Varying ◽  
Influence Of Temperature ◽  
Meshing Stiffness ◽  
Influence Of Temperature On

Under high-speed and heavy-load conditions, the influence of temperature on the gear system is extremely important. Basically, the current work on the effect of temperature mostly considers the flash temperature or the overall temperature field to cause expansion at the meshing point and then affects nonlinear factors such as time-varying meshing stiffness, which lead to the deterioration of the dynamic transmission. This work considers the effect of temperature on the material’s elastic modulus and Poisson’s ratio and relates the temperature to the time-varying meshing stiffness. The effects of temperature on the elastic modulus and Poisson’s ratio are expressed as functions and brought into the improved energy method stiffness calculation formula. Then, the dynamic characteristics of the gear system are analyzed. With the bifurcation diagram, phase, Poincaré, and fast Fourier transform plots of the gear system, the influence of temperature on the nonlinear dynamics of the gear system is discussed. The numerical analysis results show that as the temperature increases, the dynamic response of the system in the middle-speed region gradually changes from periodic motion to chaos.

Research on S-gear design, manufacturing and measuring based on NC machining center

2020 ◽  
pp. 095440542098134
Author(s):  
Shao-ying Ren ◽  
Yan-zhong Wang ◽  
Yuan Li
Keyword(s):  
Convex Surface ◽  
Coordinate Measuring Machine ◽  
Nc Machining ◽  
Tooth Profile ◽  
Numerical Control ◽  
Machining Center ◽  
Involute Gear ◽  
Measuring Machine ◽  
Gear Contact ◽  
Nc Machining Center

This article presents a method of design, manufacturing, and measuring S-gear. S-gear is a kind of gear whose tooth profile is an S-shaped curve. The sine (cosine) gear, cycloid gear, polynomial gear, and circular arc gear are all S-gears in essence. In the S-gear transmission, the concave surface of one gear and the convex surface of the other gear contact each other. Therefore, the power transmitted by S-gear is much larger than that of the convex-convex-contact involute gear. Some scholars have studied the characteristics of S-gear, but few have explored its manufacturing. In this article, the Numerical Control (NC) machining technology of S-gear is studied in detail for its industrial application. The polynomial curve is used to construct the tooth profile of the S-gear based on the Gear Meshing Theory. The mathematical model of polynomial S-gear is established, by which involute gear can be represented as a special S-gear. The steps of generating NC codes are described. Then, the S-gear sample is processed with an NC machining center. Finally, the sample is measured with a Coordinate Measuring Machine (CMM), and the measurement results show that the accuracy of the S-gear processed by the NC machining center reaches ISO6. This research provides a feasible approach for the design, manufacturing, and measuring of S-gear.

scholarly journals Dynamic Characteristics and Experimental Research of a Two-Span Rotor-Bearing System with Rub-Impact Fault

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Rui Zhu ◽  
Guang-chao Wang ◽  
Qing-peng Han ◽  
An-lei Zhao ◽  
Jian-xing Ren ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Critical Speed ◽  
Great Influence ◽  
Experimental Platform ◽  
Rotating Machine ◽  
Rotor Bearing ◽  
Before And After ◽  
Analysis System ◽  
The Stability ◽  
Bearing System

Rotor rub-impact has a great influence on the stability and safety of a rotating machine. This study develops a dynamic model of a two-span rotor-bearing system with rubbing faults, and numerical simulation is carried out. Moreover, frictional screws are used to simulate a rubbing state by establishing a set of experimental devices that can simulate rotor-stator friction in the rotor system. Through the experimental platform and its analysis system, the rubbing experiment was conducted, and the vibration of the rotor-bearing system before and after the critical speed is observed. Rotors running under normal condition, local slight rubbing, and severe rubbing throughout the entire cycle are simulated. Dynamic trajectories, frequency spectrum diagrams, chart of axis track, and Poincare maps are used to analyze the features of the rotor-bearing system with rub-impact faults under various parameters. The vibration characteristics of rub impact are obtained. Results show that the dynamic characteristics of the rotor-bearing system are affected by the change in velocity and degree of impact friction. The findings are helpful in further understanding the dynamic characteristics of the rub-impact fault of the two-span rotor-bearing system and provide reference for fault diagnosis.

scholarly journals Frequency and Vibration Characteristics of High-Speed Gear-Rotor-Bearing System with Tooth Root Crack considering Compound Dynamic Backlash

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Jie Liu ◽  
Weiqiang Zhao ◽  
Weiwei Liu
Keyword(s):  
Time Domain ◽  
Crack Depth ◽  
Transmission System ◽  
Gear System ◽  
Time Varying ◽  
Tooth Root ◽  
Meshing Stiffness ◽  
The Time Domain ◽  
Center Distance ◽  
Root Crack

Considering the microstructure of tooth surface and the dynamic characteristics of the vibration responses, a compound dynamic backlash model is employed for the gear transmission system. Based on the fractal theory and dynamic center distance, respectively, the dynamic backlash is presented, and the potential energy method is applied to compute the time-varying meshing stiffness, including the healthy gear system and the crack fault gear system. Then, a 16-DOF coupled lateral-torsional gear-rotor-bearing transmission system with the crack fault is established. The fault characteristics in the time-domain waveform and frequency response and statistics data are described. The effect of crack on the time-varying meshing stiffness is analyzed. The vibration response of three backlash models is compared. The dynamic response of the system is explored with the increase in crack depth in detail. The results show that the fault features of countershaft are more obvious. Obvious fluctuations are presented in the time-domain waveform, and sidebands can be found in the frequency domain responses when the tooth root crack appears. The effect of compound dynamic backlash on the system is more obvious than fixed backlash and backlash with changing center distance. The vibration displacement along meshing direction and dynamic meshing force increases with the increase in crack depth. Backlash and variation of center distance show different tendencies with increasing crack depth under different rotational speeds. Amplitude of the sidebands increases with crack depth increasing. The amplitude of multiplication frequency of rotational frequency has an obvious variation with growing crack depth. The sidebands of the multiplication frequency of meshing frequency show more details on the system with complex backlash and crack fault.

scholarly journals Mesh Phase Analysis of Encased Differential Gear Train for Coaxial Twin-Rotor Helicopter

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Donglin Zhang ◽  
Rupeng Zhu ◽  
Bibo Fu ◽  
Wuzhong Tan
Keyword(s):  
Phase Difference ◽  
Gear Tooth ◽  
Phase Relations ◽  
Gear Train ◽  
Time Varying ◽  
Gear Pair ◽  
Meshing Stiffness ◽  
Differential Gear ◽  
Starting Point ◽  
Twin Rotor

Dynamic excitation caused by time-varying meshing stiffness is one of the most important excitation forms in gear meshing process. The mesh phase relations between each gear pair are an important factor affecting the meshing stiffness. In this paper, the mesh phase relations between gear pairs in an encased differential gear train widely used in coaxial twin-rotor helicopters are discussed. Taking the meshing starting point where the gear tooth enters contact as the reference point, the mesh phase difference between adjacent gear pairs is analyzed and calculated, the system reference gear pair is selected, and the mesh phase difference of each gear pair relative to the system reference gear pair is obtained. The derivation process takes into account the modification of the teeth, the processing, and assembly of the duplicate gears, which makes the calculation method and conclusion more versatile. This work lays a foundation for considering the time-varying meshing stiffness in the study of system dynamics, load distribution, and fault diagnosis of compound planetary gears.

Impact Study of Mass Eccentricity of Sniper Rifle Bullet on Initial Disturbance

2014 ◽  
Vol 1006-1007 ◽  
pp. 275-279
Author(s):  
Guo Qing Liu ◽  
Cheng Xu
Keyword(s):  
Angular Displacement ◽  
Great Influence ◽  
Coupling Model ◽  
Initial Position ◽  
Initial Disturbance ◽  
Mass Center ◽  
Nonlinear Finite Element Method ◽  
Mass Eccentricity ◽  
Calculation Results ◽  
The Impact

The bullet-rifle coupling model of sniper rifle has established to study the impact of bullet mass eccentricity on initial disturbance. This coupling model was established based on nonlinear finite element method and used to simulate the launch process of sniper rifle under the condition of gravity static equilibrium in the method of the mixing calculation which had advantages of both dynamic explicit algorithm and static implicit algorithm. The impact of different initial position of mass center on bullet swing angular displacement and centroid displacement was considered. Numerical calculation results shows that bullet mass eccentricity has a great influence on initial disturbance, the bullet swing angular displacement and centroid displacement is closely related to initial position of mass center. In addition, there is proportionality between bullet swing angular displacement and axial velocity before it reaches limit. That is helpful to carry out further study of how to control the influence of mass eccentricity on initial disturbance.

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