Investigation of Effects of Additive for ATF and Test Condition on Pitting Life of Gear Tooth in the FZG Pitting Test

2011 ◽  
Author(s):  
Toshihiko Ichihashi ◽  
Yutaka Takakura ◽  
Susumu Matsumoto
Keyword(s):  
Fuel Economy ◽  
Gear Tooth ◽  
Automatic Transmission ◽  
Tooth Surface ◽  
Severe Condition ◽  
Gear Teeth ◽  
Tooth Width ◽  
Sulfur Containing ◽  
Transmission Gear ◽  
Transmission Test

The reduction in viscosity of Automatic Transmission Fluids (ATFs) for improving fuel economy results in a reduction in transmission gear fatigue life due to occurring pitting. The aim of this study is to establish a suitable test condition for evaluating differentiation in the gear pitting life between ATFs by using a Forschungsstelle fur Zahnrader und Getriebebau (FZG). In this study FZG gear sets were modified so that gear teeth were misaligned and the contact tooth width was shortened by offset in the direction of the shaft. The fatigue pitting life in response to ATFs under this modified FZG test condition was of the same order as that obtained in the actual transmission test under a severely offset condition. A sulfur-containing additive could play a role on the gear tooth life under severe condition, which was most likely attributed to tribofilm for motion on the gear tooth surface.

Analytical Reconstruction of the Running Surfaces of Gear Teeth Using Standard Profile and Lead Measurements

1983 ◽  
Vol 105 (4) ◽  
pp. 725-735 ◽  
Author(s):  
W. D. Mark
Keyword(s):  
Gear Tooth ◽  
Tooth Surface ◽  
Spur Gears ◽  
Gear Teeth ◽  
Tooth Width ◽  
Least Squares Fit ◽  
Geometric Deviations ◽  
Standard Profile ◽  
Involute Surface ◽  
Class Of Functions

A method is developed for analytically reconstructing the geometric deviations of the running surface of a gear tooth from a perfect involute surface. The method uses standard profile and lead deviation measurements and is applicable to both helical and spur gears. The reconstruction is carried out by using normalized Legendre polynomials. For this class of functions, it is shown that the optimum locations of the profile and lead deviation measurements are the locations of the zeros of the Legendre polynomial of degree equal to the number of profile or lead deviation measurements taken–after appropriate normalization of the tooth width or depth, as appropriate. A least squares fit procedure for establishing a common origin of ordinates for sets of profile and lead deviation measurements is formulated, and its solution is carried out in closed form. Account is taken of the noninsignificant errors that typically arise in profile and lead deviation measurements so that the final analytically reconstructed tooth surface is free of inconsistencies.

scholarly journals An Analysis of the Surface Geometric Structure and Geometric Accuracy of Cylindrical Gear Teeth Manufactured with the Direct Metal Laser Sintering (DMLS) Method

2019 ◽  
Author(s):  
Jadwiga Małgorzata Pisula ◽  
Grzegorz Budzik ◽  
Łukasz Przeszłowski
Keyword(s):  
Surface Roughness ◽  
Geometric Structure ◽  
Gear Tooth ◽  
Spur Gear ◽  
Laser Sintering ◽  
Tooth Surface ◽  
Direct Metal Laser Sintering ◽  
Cylindrical Gear ◽  
Sand Blasting ◽  
Gear Teeth

This paper presents findings concerning the accuracy of the geometry of cylindrical spur gear teeth manufactured with the direct metal laser sintering (DMLS) method. In addition, the results of the evaluation of the tooth surface geometric structure are presented in the form of selected two-dimensional and three-dimensional surface roughness parameters. An analysis of the accuracy of the fabricated gear teeth was performed after gear sand-blasting and gear tooth milling processes. Surface roughness was measured before and after sand-blasting and gear tooth milling. The test gear wheel was manufactured from GP1 high-chromium stainless steel on an EOS M270 machine.

scholarly journals Study on Wear Characteristics Evolution of Helical Gear With Linear Initial Defect

2021 ◽  
Author(s):  
Yuqi Zhu ◽  
Wei Yuan ◽  
Qianjian Guo ◽  
Liguo Zhang ◽  
Wenhua Wang ◽  
...  
Keyword(s):  
Oil Pollution ◽  
Gear Tooth ◽  
Lubricating Oil ◽  
Tooth Surface ◽  
Wear Characteristics ◽  
Wear Process ◽  
Initial Defect ◽  
Hard Particles ◽  
Wear Life ◽  
Tooth Width

Abstract The initial defects have greatly affected the gear transmission under harsh working conditions in the fields of wind power and ships. The influence of linear initial defects on the evolution of wear characteristics of helical gears was studied. The laser marking device was used to process the linear initial defect along the tooth width direction, and the gear without initial defect was used for comparison. It can be concluded that the linear initial defect changed the meshing state of the gear tooth, and greatly shortened the normal wear life of the gear, the normal wear life of the gear is shortened by about 45%, and the wear rate in the stable wear stage is increased by about 56%, a great deal of pitting corrosion and plastic flow on the tooth surface occurred in the pitch circle position of the defective gear. In addition, the lubrication condition deteriorated in the later period caused by lubricating oil pollution and the hard particles falling off the gearbox bearings entered the meshing surface and the emerged crack, which further accelerated the wear process of gear.

Contact between Logarithmic Crowned Teeth of Spur Gear Transmission

2015 ◽  
Vol 740 ◽  
pp. 69-78 ◽  
Author(s):  
Ting Ting Jin ◽  
Jiu Gen Wang ◽  
Shou Song Jin ◽  
Zhen Rong Wang
Keyword(s):  
Stress Concentration ◽  
Gear Tooth ◽  
Subsurface Layer ◽  
Spur Gear ◽  
Gear Transmission ◽  
Von Mises Stress ◽  
Tooth Surface ◽  
Gear Teeth ◽  
Deformation Equation ◽  
Von Mises

Gear tooth modification such as lead crowning can reduce stress concentration at the edges of the gear teeth; therefore prolong the fatigue life of gears. A logarithmical lead profile was applied on spur gears and the surface coordinate equation of logarithmic crowned tooth for manufacturing was established. On the basis of the contact mechanics model, the deformation equation of compatibility and load equilibrium equation were solved with an iterative numerical algorithm, and the corresponding programs were developed in Matlab to calculate the distributions of contact stress and von Mises stress field inside the subsurface layer at any meshing position. The numerical results of some typical examples show that the level of stress concentration before modification changes with the engaging locations of the gear teeth, and so does the amount of logarithmic modification along the line of contact, which can completely eliminate the edge effects of tooth surface at every meshing position during the spur gear transmission process, and thus improves the fatigue resistance of gear teeth surfaces.

Theoretical Analysis of the Strength of Internal Gear Drive With Zero-Tooth-Difference

2001 ◽  
Author(s):  
Shijie Wang ◽  
Guang Hong
Keyword(s):  
Theoretical Basis ◽  
Gear Tooth ◽  
Tangential Direction ◽  
Tooth Surface ◽  
Coupling Mechanism ◽  
Bending Stress ◽  
Gear Teeth ◽  
Gear Drive ◽  
Pumping System ◽  
Internal Gear

Abstract In this paper we apply internal gear drive pair, with zero-tooth-difference, in the coupling mechanism to connect the output shaft of reducer and the rotor of pump in the submerged-motor-driven PC pumping system for oil production. Because there are dual modifications along radial and tangential direction for the cut of gear teeth, the gear-tooth thickness will be reduced and thus the strength of the teeth will be weakened evidently. At present, there is no theoretical criteria for the strength verification suitable for such mechanism design. The new calculating formulae for contacting stress of tooth surface and bending stress of tooth-root were established in this paper just for this reason, which not only provide the strength verifying criteria for gear-tooth but can also be regarded as the theoretical basis for the design of internal gear drive mechanism with zero-tooth-difference.

A Generalized Kinematics and Power Flow Analysis Methodology for Automatic Transmission Gear Trains

2003 ◽  
Author(s):  
A. Kahraman ◽  
K. Kienzle ◽  
D. M. Zini
Keyword(s):  
Power Flow ◽  
Search Algorithm ◽  
Gear Tooth ◽  
Automatic Transmission ◽  
Flow Analysis ◽  
Planetary Gear ◽  
Gear Train ◽  
Power Flow Analysis ◽  
Planetary Gear Sets ◽  
Transmission Gear

A generalized formulation for analyzing speeds and forces of the gear components of planetary automatic transmissions is proposed. The formulation is capable of analyzing any typical one-degree-of-freedom automatic transmission gear train containing any number of simple, compound or complex-compound planetary gear sets. It consists of three components: a kinematic analysis formulation, a gear ratio and kinematic configuration search algorithm, and a power flow analysis formulation. The kinematics module computes rotational speeds of gears and carriers. Given the type and number of planetary gear sets, the search module determines all possible kinematic configurations and gear tooth count combinations that result in a required set of gear ratios while eliminating all kinematic redundancies and unfavorable clutching sequences. The third component, the power-flow analysis formulation, performs a complete static force (power flow) analysis to determine all gear and bearing forces, and clutch and connection torque values. A five-speed transmission example is considered to highlight the capabilities of the proposed formulation.

scholarly journals Experimental Analysis of Residual Stress and Bending Strength of Gear Tooth Surface after Shot Peening Treatment

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Dong Liang ◽  
Sheng Meng ◽  
Yi Chen ◽  
Chengli Hua
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Shot Peening ◽  
Bending Strength ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Bending Fatigue ◽  
Gear Teeth ◽  
Tooth Surfaces ◽  
Bending Fatigue Strength

The fatigue strength of a gear tooth surface is affected by various factors, which subsequently impacts the transmission performance of gears. Usually, shot peening treatment is carried out during processing to improve the performance of gears. Most current studies focus on theoretical descriptions and simulation analyses of shot peening treatment. However, in this paper, the relationships among shot peening treatment, residual stress, and bending fatigue strength of a gear tooth surface are discussed, through experimental methods. Based on X-ray stress analysis, at select locations on the test samples, the residual stresses on gear tooth surfaces with and without shot peening treatment are determined and contrasted. The results show that shot peening treatment can effectively increase the residual stress on gear tooth surfaces. In addition, an electromagnetic resonance fatigue tester is used to analyze the bending fatigue strength of gear tooth surfaces. The test results indicate that the bending fatigue strength of the gear teeth with shot peening is higher than that of the gear teeth without shot peening. The obtained conclusions lay the foundation for further practical engineering applications of gears.

Characteristics of a Modified Double Enveloping Worm Gear Drive

1992 ◽  
Author(s):  
Vilmos Simon
Keyword(s):  
Gear Tooth ◽  
Worm Gear ◽  
Performance Characteristics ◽  
Tooth Surface ◽  
Gear Teeth ◽  
Gear Drive ◽  
Load Distributions ◽  
Worm Gearing ◽  
Axial Profile ◽  
New Type

Abstract A modified new type of double enveloping worm gearing is developed. The gear tooth surface is generated by a flying tool whose cutting edge has the modified profile of the entering edge of the worm, and the worm surface has a straight-lined axial profile and circular lead changed to the established rule. The same rule governs the motion of the flying tool in processing the gear teeth. To compare the performance characteristics of the classical and the modified new type of double enveloping worm gearings, the load distributions are calculated and the elastohydrodynamic analysis of lubrication is carried out for both types of worm gearings. The obtained results show the advantages of the new type of double enveloping worm gear drive.

Identification of the Machine Settings of Real Hypoid Gear Tooth Surfaces

1998 ◽  
Vol 120 (3) ◽  
pp. 429-440 ◽  
Author(s):  
C. Gosselin ◽  
T. Nonaka ◽  
Y. Shiono ◽  
A. Kubo ◽  
T. Tatsuno
Keyword(s):  
Manufacturing Industry ◽  
Gear Tooth ◽  
Computer Software ◽  
Tooth Surface ◽  
Hypoid Gear ◽  
Gear Teeth ◽  
Tooth Surfaces ◽  
Gear Manufacturing ◽  
Pattern Development ◽  
Cutting Processes

In the spiral bevel and hypoid gear manufacturing industry, master gear sets are usually developed from initial machine settings obtained from computer software or instruction sheets. These initial machine settings are then modified until a satisfactory bearing pattern is obtained, a process called bearing pattern development. Once a satisfactory bearing pattern is obtained, manufacturing errors and heat treatment distorsions can be accounted for by proportionally changing the machine settings according to the results of a V-H test in which the pinion vertical and horizontal positions are modified until the bearing pattern is acceptable. Once a satisfactory combination of master pinion and gear is obtained, their actual tooth surfaces usually do not correspond to those of the initial theoretical model, and the theoretical pinion and gear surface definitions are unknown. This paper presents a computer algorithm used to identify the machine settings producing a theoretical tooth surface closest to that of a measured surface, what the authors call Surface Match, in order to effectively simulate the kinematical behavior of real gear teeth. The approach is applicable to both 1st and 2nd order surface errors, including profile deviation, for any cutting process. However, given the availability of experimental data for the Fixed Setting™, Formate™ and Helixform™ cutting processes, the examples presented in the paper are related to these cutting processes.

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