scholarly journals Dynamic Characteristics of Spur Gear Pair with Dynamic Center Distance and Backlash

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Jie Liu ◽  
She Liu ◽  
Weiqiang Zhao ◽  
Lei Zhang
Keyword(s):  
Rotational Speed ◽  
Chaotic Behavior ◽  
Nonlinear Differential Equations ◽  
Spur Gear ◽  
Reference Source ◽  
Vibration Displacement ◽  
Frequency Components ◽  
Chaos Motion ◽  
Six Degree Of Freedom ◽  
Center Distance

Effect of dynamic backlash and rotational speed is investigated on the six-degree-of-freedom model of the gear-bearing system with the time-varying meshing stiffness. The relationship between dynamic backlash and center distance can be defined clearly. The nonlinear differential equations of the model are solved by the Newmark-β method. The results show that system amplitude increases in the wake of increasing rotational speed. After reaching a certain rotational speed, the system jumps from periodic motion to chaos motion, and the effective amplitude is changed violently. Comparing the dynamic backlash with fixed backlash, the amplitude of the dynamic backlash is augmented and the frequency components are diversified. The vibration displacement is enlarged by the dynamic backlash and the chaotic behavior of the system becomes complex with increasing rotational speed. The numerical results provide a useful reference source for engineers to select rotational speed section for steady running.

Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

1996 ◽  
Vol 118 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Chuen-Huei Liou ◽  
Hsiang Hsi Lin ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Spur Gear ◽  
Tooth Size ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Wide Range ◽  
Gear Contact ◽  
Center Distance ◽  
Selection Of ◽  
Better Than

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

scholarly journals 3D-Modeling and Motion Simulation of Composite Wheel Gears Transmission Based on UG

2018 ◽  
Vol 175 ◽  
pp. 03006
Author(s):  
Mingxia Zhao
Keyword(s):  
3D Modeling ◽  
Rotational Speed ◽  
Spur Gear ◽  
Transmission Mechanism ◽  
Gear Train ◽  
Gear Pair ◽  
Calculation Formula ◽  
Motion Simulation ◽  
Gear Trains ◽  
Simulation Parameters

Taking the compound gear trains as an example, the principle of the transmission mechanism was analyzed, and the rotational speed of the key gears in the compound gear trains was calculated by using the calculation formula of transmission ratio to obtain the simulation parameters of UG movement. The gear tool box in UG was applied to complete the modeling and meshing assembly of the bevel gear and spur gear, the rotation pair and gear pair was to motion simulation, the gear transmission state could have visually observed by motion simulation, and then the chart was analyzed to verify the design rationality of the gear train.

scholarly journals Optimal Tooth Numbers for Compact Standard Spur Gear Sets

1982 ◽  
Vol 104 (4) ◽  
pp. 749-757 ◽  
Author(s):  
M. Savage ◽  
J. J. Coy ◽  
D. P. Townsend
Keyword(s):  
Optimal Design ◽  
Objective Function ◽  
Design Space ◽  
Spur Gear ◽  
Gear Ratio ◽  
Contact Ratio ◽  
Bending Fatigue ◽  
Gear Mesh ◽  
Compact Design ◽  
Center Distance

The design of a standard gear mesh is treated with the objective of minimizing the gear size for a given ratio, pinion torque, and allowable tooth strength. Scoring, pitting fatigue, bending fatigue, and the kinematic limits of contact ratio and interference are considered. A design space is defined in terms of the number of teeth on the pinion and the diametral pitch. This space is then combined with the objective function of minimum center distance to obtain an optimal design region. This region defines the number of pinion teeth for the most compact design. The number is a function of the gear ratio only. A design example illustrating this procedure is also given.

A Theoretical Model for Self-Excited Vibrations in Hydraulic Gates, Valves and Seals

1980 ◽  
Vol 102 (2) ◽  
pp. 146-151 ◽  
Author(s):  
D. S. Weaver ◽  
S. Ziada
Keyword(s):  
Theoretical Model ◽  
Discharge Coefficient ◽  
Nonlinear Differential Equations ◽  
Check Valve ◽  
Structural Stiffness ◽  
Fluid Inertia ◽  
Vibration Displacement ◽  
Runge Kutta Method ◽  
Flow Control Devices ◽  
Control Devices

A general theoretical model is presented for the jet flow mechanism of self-excited vibrations of flow control devices operating at small openings. The coupled nonlinear differential equations are solved numerically using the Runge-Kutta method. The vibration displacement and discharge characteristics are given for a variety of parameters such as structural stiffness, fluid inertia and discharge coefficient. The predictions are shown to agree reasonably well with the experimental observations of swing check valve vibrations.

Dynamic Model of Gears with Trapped Oil and Coupled Analysis in External Spur-Gear Pump

2011 ◽  
Vol 130-134 ◽  
pp. 610-615 ◽  
Author(s):  
Yu Long Li ◽  
Kun Liu ◽  
Fu Chun Sun
Keyword(s):  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Contact Stiffness ◽  
Spur Gear ◽  
Vibration Characteristics ◽  
Coupled Analysis ◽  
Vibration Velocity ◽  
Gear Pump ◽  
Vibration Displacement ◽  
The Impact

In order to understand the vibration characteristics of gears based on trapped-oil in external spur-gear pump, from the calculations of trapped-oil pressure and hydraulic load and contact stiffness and trapped-oil stiffness, etc., a dynamic model coupled with trapped-oil pressure was derived for the gears, then an iterative operation based on Runge-Kutta method was used for analyzing the model, therefore the data related to trapped-oil pressure and the vibration displacement and the vibration velocity were obtained in a periodic of trapped oil, and the impact of different backlash value and different distance between two unloading grooves on trapped oil pressure and dynamic characteristics of gears was briefly analyzed. All results of simulation showed that trapped-oil pressure and trapped-oil stiffness had greater impact on vibration characteristics of gears in external spur-gear pump, trapped-oil stiffness could reduce the vibration of the gears; in simulation of trapped-oil pressure, dynamic trapped-oil model related to dynamic characteristics of gears more accurate than the static trapped-oil model irrelated to dynamic characteristics of gears; the trapped-oil pressures in two trapped-oil cavity were different, the vibration characteristics of gears was better that in larger backlash value, etc.. Finally, by the trapped-oil stiffness of the external gear pump is unique, the important conclusions are educed that the vibration of gears in external spur-gear pump is indeed different from conventional gears and so on.

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