Wear of Involute Spur Gears With Asymmetric Teeth Under Dynamic Loading

Tribology ◽  
2006 ◽  
Author(s):  
F. Karpat ◽  
S. Ekwaro-Osire
Keyword(s):  
Aerospace Industry ◽  
Tooth Wear ◽  
Wear Depth ◽  
Spur Gears ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Wear Model ◽  
Extreme Performance ◽  
Gear Contact ◽  
The Relationship

Spur gears with asymmetric teeth have a significant potential for some applications requiring extreme performance like in the aerospace industry. In this study, the influence of tooth wear on the dynamic behavior of involute spur gears with asymmetric teeth is analyzed. The Archard's wear model was adopted in formulating and accounting for wear. Effects of gear parameters such as gear contact ratio, tooth height, mesh stiffness, and pressure angles on tooth wear are considered. These parameters are used to describe the relationship between dynamic tooth load and tooth wear. A comparison of symmetric and asymmetric teeth is also presented with respect to tooth wear. Sample simulation results, which were obtained by using an in-house developed computer program, are illustrated with numerical examples. The numerical results match well with the practical and analytical results which are available in literature. For asymmetric teeth, it was shown that the wear depth decreased with increasing pressure angle on drive side.

A Virtual Tool for Wear Simulation of Plastic Gear Pairs

2013 ◽  
Author(s):  
F. Karpat ◽  
S. Ekwaro-Osire ◽  
C. Yüce ◽  
E. Karpat
Keyword(s):  
Analytical Approach ◽  
Failure Modes ◽  
Wear Behavior ◽  
Load Capacity ◽  
Tooth Wear ◽  
Wear Depth ◽  
Spur Gears ◽  
Automotive Applications ◽  
Wear Model ◽  
Plastic Gears

Currently plastic gears are widely used in industry, and not only for lightly loaded applications like household appliances, tools, and toys, but also in the more demanding areas of machinery in automotive applications. However there is a need to investigate important properties such as load capacity, endurance, cost, life, stiffness and wear. Tooth wear is one of the major failure modes in plastic gears just like with steel gears. This paper focuses on the simulation of wear for standard and non-standard gears using an analytical approach. A numerical model for wear prediction of gear pairs is developed. A wear model based on Archard’s equation is employed to predict wear depth. The variation of the contact load generated by the cumulative tooth profile wear is simulated and examined. A MATLAB-based virtual tool is developed to analyze wear behavior of standard and non-standard spur gears depending on various gear parameters. In this paper, this virtual tool is introduced with numerical examples.

The Effect of Tooth Wear on the Dynamic Transmission Error of Helical Gears with Smaller Number of Pinion Teeth

2014 ◽  
Vol 657 ◽  
pp. 649-653 ◽  
Author(s):  
Virgil Atanasiu ◽  
Cezar Oprişan ◽  
Dumitru Leohchi
Keyword(s):  
Dynamic Contact ◽  
Tooth Wear ◽  
Transmission Error ◽  
Analytical Investigation ◽  
Helical Gear ◽  
Wear Depth ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Helical Gears ◽  
Dynamic Transmission Error

The paper presents an analytical investigation of the effect of the tooth wear on the dynamic transmission error of helical gear pairs with small number of pinion teeth. Firstly, the dynamic analysis is conducted to investigate only the effect of the time-varying mesh stiffness on the variation of dynamic transmission error along the line of action. Then, the tooth wear effect on the dynamics of helical gear with small number of pinion teeth is being researched. In the analysis, instantaneous dynamic contact analysis is used in wear depth calculations. A comparative study was performed to investigate the relation between total contact ratio, mesh stiffness and dynamic transmission error of helical gear pairs with small number of teeth.

Dynamic Analysis of High-Contact-Ratio Spur Gears With Asymmetric Teeth

2008 ◽  
Author(s):  
F. Karpat ◽  
S. Ekwaro-Osire
Keyword(s):  
Numerical Technique ◽  
Spur Gear ◽  
Dynamic Loads ◽  
Spur Gears ◽  
Load Carrying Capacity ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Gear Teeth ◽  
Load Carrying ◽  
Gear Contact

In this research, a numerical technique is used to study the performance of high-contact-ratio (HCR) spur gears with asymmetric teeth. Asymmetric teeth have been shown to minimize dynamic loads and to increase the load carrying capacity. This is due to the fact that these teeth have a larger pressure angle on the drive side compared to the coast side. In literature, symmetric gear teeth with HCR have been shown to also yield low dynamic loads and high load capacities. HCR gears have these positive attributes because for gears in a mesh, the number of tooth pairs sharing the transmitted load alternates between two and three. In this study, the separate benefits of an HCR gear and asymmetric teeth are unified into a spur gear with asymmetric teeth. In this case, the effect of the gear contact ratio, addendum factor, mesh stiffness, pressure angles, and operation speeds on dynamic tooth loads are considered. The influences of these parameters on dynamic response are presented and discussed. A comparison between standard and non standard gear pairs in literature is also presented, with respect to dynamic tooth loads. Sample simulation results, which were obtained by using an in-house computer program, are discussed. The results obtained are shown to match well with some related analytical and experimental results in literature. It is further demonstrated that HCR spur gears with asymmetric teeth do provide a marked advantage compared to the conventional spur gears with symmetric teeth.

Studies on the Dynamic Performance of a Spur Gear With Hollow Teeth

1992 ◽  
Author(s):  
A. Ramamohana Rao ◽  
B. Srinivasulu
Keyword(s):  
Damping Ratio ◽  
Dynamic Performance ◽  
Spur Gear ◽  
Dynamic Loads ◽  
Response Analysis ◽  
Spur Gears ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Direction Parallel ◽  
Gear Teeth

Abstract Performance of spur gears largely depends on the magnitude and nature of variation of dynamic loads occuring between mating teeth. Variable tooth mesh stiffness is one of the primary sources causing parametric excitations resulting in dynamic loads. The usual method of varying the mesh stiffness to reduce dynamic loads is to use high contact ratio and profile modified gears. In this paper, a new type of tooth design to improve the dynamic performance of spur gears is presented. In this, a through hole is drilled in each tooth in a direction parallel to the gear axis. The diameter of the hole and its position on the tooth centre line are variable. Such a gear is called a hollow gear. Dynamic analysis is carried out for the mesh of hollow pinions mating with solid gears. The results are compared with solid pinions (no holes in teeth) meshing with solid gears. Finite element method is used for the analysis. For estimation of the dynamic load variation in hollow-solid and solid-solid gear meshes, a model incorporating the varying mesh stiffness and damping of gear teeth is used. Governing differential equations are solved using unconditionally stable Newmark-beta algorithm. The dynamic loads obtained are used as an input time varying loads for the determination of dynamic fillet and hole stress response of solid and hollow gear teeth whichever is applicable. Modal superposition technique is used for transient response analysis. The study shows that for the same damping ratio, dynamic loads in hollow-solid meshes are nearly the same as in a solid-solid mesh. In reality, the dynamic loads in a hollow-solid mesh are less than a solid-solid mesh due to its inherent higher material damping.

scholarly journals Wear of Spur Gears Having a Dithering Motion and Lubricated With a Perfluorinated Polyether Grease

2007 ◽  
Author(s):  
Timothy Krantz ◽  
Fred Oswald ◽  
Robert Handschuh
Keyword(s):  
Wear Rate ◽  
High Speed ◽  
Failure Modes ◽  
Load Level ◽  
Wear Depth ◽  
Spur Gears ◽  
Test Load ◽  
Total Wear ◽  
Gear Contact ◽  
Perfluorinated Polyether

Gear contact surface wear is one of the important failure modes for gear systems. Dedicated experiments are required to enable precise evaluations of gear wear for a particular application. The application of interest for this study required evaluation of wear of gears lubricated with a grade 2 perfluorinated polyether grease and having a dithering (rotation reversal) motion. Experiments were conducted using spur gears made from AISI 9310 steel. Wear was measured using a profilometer at test intervals encompassing 10,000 to 80,000 cycles of dithering motion. The test load level was 1.1 GPa maximum Hertz contact stress at the pitch-line. The trend of total wear as a function of test cycles was linear, and the wear depth rate was approximately 1.2 nm maximum wear depth per gear dithering cycle. The observed wear rate was about 600 times greater than the wear rate for the same gears operated at high speed and lubricated with oil.

Parametric vibration of split gears induced by time-varying mesh stiffness

2014 ◽  
Vol 229 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Dongsheng Zhang ◽  
Shiyu Wang
Keyword(s):  
Parametric Vibration ◽  
Design Parameters ◽  
Time Varying ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Rotational Model ◽  
Helical Gears ◽  
Multi Scale ◽  
Rotational Vibration ◽  
The Relationship

Time-varying mesh stiffness is a significant excitation source within gear systems. Split gear (or laminated gear, phase gear) is an interesting design using equally phased gear-slices, which can remarkably reduce the mesh stiffness fluctuation like helical gears but completely avoid the axial force. This work examines a split gear pair to address the suppression of the mesh stiffness fluctuation and rotational vibration thereof, especially the relationship between the key design parameters including the number of slice, contact ratio, and damping, and the parametric vibration. For these aims, this work develops a purely rotational model, based on which the multi-scale method is employed to determine stability boundaries. The results imply that the unstable zones are related to the mesh phase determined by the number of slices and contact ratio, and these zones can be diminished by the damping. The analytical predictions are numerically verified by Floquet theory.

scholarly journals Geometry and design of spur gear drive associated with low sliding ratio

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110125
Author(s):  
Wei Sheng ◽  
Zhengminqing Li ◽  
Hong Zhang ◽  
Rupeng Zhu
Keyword(s):  
Gear Tooth ◽  
Tooth Wear ◽  
Spur Gear ◽  
Transmission Efficiency ◽  
Contact Ratio ◽  
Gear Drive ◽  
Solid Models ◽  
Tooth Surfaces ◽  
The Relationship ◽  
Cubic Function

The relative sliding between tooth surfaces is the main cause of tooth wear and power loss, which directly affects the transmission efficiency and durability of gear. The aim of this paper is to provide a method to design such spur gear with low sliding ratio (LSR). Based on kinematics, differential geometry and contact path, the general mathematical models of the generating rack, the pinion and the mating gear tooth profiles are established in turn. Then, according to the relationship between the contact path and sliding ratio, a contact path described by a cubic function is proposed to construct a spur gear drive with low sliding ratio. In order to ensure the continuity of action and non-interference, solid models of the mated gear pair are established, and the motion simulation is carried out by an example. Moreover, the effects of the contact path function coefficients on sliding ratio, tooth shape, and contact ratio are analyzed. Meshing efficiency and tooth wear of LSR gear drive are evaluated by comparing with those of the involute gear drive. The results show that, this LSR spur gear drive has higher transmission efficiency and better anti-wear performance.

Reduction of Vibration in Spur Gears by an Asymmetric Tooth Profile With High Contact Ratio

2017 ◽  
Author(s):  
Ryo Fujikawa ◽  
Kiyotaka Ikejo ◽  
Soichi Ibaraki ◽  
Kazuteru Nagamura
Keyword(s):  
Thrust Force ◽  
Spur Gear ◽  
Tooth Profile ◽  
Spur Gears ◽  
Gear Pair ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Gear Drive ◽  
Gear Drives ◽  
Helical Gear Pair

Gear drive is a mechanism transmitting a power and a motion through the teeth contact. The number of teeth in contact changes during a mesh cycle. That raises a discontinuity of the mesh stiffness, and causes a gear vibration. The discontinuity implies a direct relationship with the contact ratio of the gear pair. In general, the high contact ratio more than two decreases the discontinuity of the mesh stiffness. Therefore, the increase of the contact ratio is able to reduce the vibration and the noise in the gear drives. An adoption of a helical gear pair is a method to obtain two or more contact ratio. However, that provides a thrust force and a difficulty to machine and assemble. For a spur gear pair, though it is possible to increase the contact ratio by stretching the tooth depth, the tooth thickness may reduce or be excessively sharp at the tooth tip on the addendum circle. In this study, we designed and made a high contact ratio spur gear pair with an asymmetric tooth profile. The gear pair has a large tooth depth to increase the contact ratio, and the asymmetric tooth profile to prevent the sharpness of tooth at the tip circle. In the running test, the vibration and the noise were measured. Consequently, we succeeded in a reduction of vibration and noise in spur gear drives with the asymmetric tooth profile.

Mesh Stiffness Calculation of Spur Gears With Tooth Surface Crack

2019 ◽  
Author(s):  
Luke Zhang ◽  
Yimin Shao
Keyword(s):  
Surface Crack ◽  
Theoretical Basis ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Spur Gears ◽  
Mesh Stiffness ◽  
Early Failure ◽  
Proposed Model ◽  
Potential Energy Method ◽  
The Relationship

Abstract Tooth surface crack is an early fault before spalling, which has an important influence on mesh stiffness and vibration characteristics of the gear system. However, the researches on tooth surface crack are limited as scholars pay little attention to this early fault. In this study, an analytical model of spur gears with tooth surface crack is established. Using the potential energy method, the equations for mesh stiffness calculation of spur gears with tooth surface crack are derived. By adopting the proposed model, the influences of tooth surface crack fault on mesh stiffness of gear tooth are studied. The relationship between tooth surface crack and mesh stiffness of gear tooth under different lengths and depths can be further calculated. This study provides a theoretical basis for the diagnosis of early failure of spalling.

A Prediction Method of Wear on Tooth Surface for Spur Gears

2013 ◽  
Author(s):  
Shotaro Inoue ◽  
Kiyotaka Ikejo ◽  
Kazuteru Nagamura ◽  
Natsuhiko Seyama ◽  
Shinya Nakagawa
Keyword(s):  
Failure Modes ◽  
Gear Tooth ◽  
Testing Machine ◽  
Prediction Method ◽  
Tooth Wear ◽  
Spur Gear ◽  
Tooth Surface ◽  
Wear Depth ◽  
Spur Gears ◽  
Gear Drives

Gear drives are widely used in various mechanical systems. Therefore, the understanding for the failure mode of gear tooth provides the improvement of various machines. The wear on the tooth surface is one of the important failure modes for the gear drives. The tooth wear changes its profile, and frequently increases gear vibration and noise. However, there are many unclear phenomena about the wear on the tooth surface for the gear drive. In this study, we investigated wear of spur gear using a power circulating-type gear testing machine, and measured the change in tooth profile of the test gears. Furthermore, we developed a computer program to predict the amount of the wear on the tooth surface for the spur gears. The method employs two equations. One is based on the wear theory under lubricated condition that was deduced by Soda. The other is derived from the ploughing wear model. Using these equations, the wear depth on the tooth surface is calculated with the contact stress, the sliding velocity, the oil film thickness, etc. The calculated value of the wear agreed with the experimental data.

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