scholarly journals A Review on Micropitting Studies of Steel Gears

Coatings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 42 ◽  
Author(s):  
Huaiju Liu ◽  
Heli Liu ◽  
Caichao Zhu ◽  
Ye Zhou
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Gear Tooth ◽  
Influence Factors ◽  
Contact Fatigue ◽  
Tooth Surface ◽  
Case Hardening ◽  
Heavy Load ◽  
Surface Topographies ◽  
Gear Manufacturing

With the mounting application of carburized or case-hardening gears and higher requirements of heavy-load, high-speed in mechanical systems such as wind turbines, helicopters, ships, etc., contact fatigue issues of gears are becoming more preponderant. Recently, significant improvements have been made on the gear manufacturing process to control subsurface-initiated failures, hence, gear surface-initiated damages, such as micropitting, should be given more attention. The diversity of the influence factors, including gear materials, surface topographies, lubrication properties, working conditions, etc., are necessary to be taken into account when analyzing gear micropitting behaviors. Although remarkable developments in micropitting studies have been achieved recently by many researchers and engineers on both theoretical and experimental fields, large amounts of investigations are yet to be further launched to thoroughly understand the micropitting mechanism. This work reviews recent relevant studies on the micropitting of steel gears, especially the competitive phenomenon that occurs among several contact fatigue failure modes when considering gear tooth surface wear evolution. Meanwhile, the corresponding recent research results about gear micropitting issues obtained by the authors are also displayed for more detailed explanations.

A parameterized numerical method for generating discrete helical gear tooth surface allowing non-standard geometry

2008 ◽  
Vol 222 (6) ◽  
pp. 1033-1038 ◽  
Author(s):  
J Hedlund ◽  
A Lehtovaara
Keyword(s):  
Gear Tooth ◽  
Numerical Approach ◽  
Helical Gear ◽  
Tooth Surface ◽  
Tool Profile ◽  
Standard Geometry ◽  
Gear Manufacturing ◽  
Involute Gears ◽  
Gear Geometry ◽  
Tooth Flank

Gear analysis is typically performed using calculation based on gear standards. Standards provide a good basis in gear geometry calculation for involute gears, but these are unsatisfactory for handling geometry deviations such as tooth flank modifications. The efficient utilization of finite-element calculation also requires the geometry generation to be parameterized. A parameterized numerical approach was developed to create discrete helical gear geometry and contact line by simulating the gear manufacturing, i.e. the hobbing process. This method is based on coordinate transformations and a wide set of numerical calculation points and their synchronization, which permits deviations from common involute geometry. As an example, the model is applied to protuberance tool profile and grinding with tip relief. A fairly low number of calculation points are needed to create tooth flank profiles where error is <1 μm.

Basic Understanding of Gears

2005 ◽  
pp. 1-18
Keyword(s):  
Gear Tooth ◽  
Heat Treating ◽  
Case Hardening ◽  
Basic Understanding ◽  
Gear Manufacturing ◽  
Manufacturing Methods ◽  
Processing Steps ◽  
Selection Of

Abstract This chapter begins with a review of some of the terms used in the gear industry to describe the design of gears and gear geometries. It then discusses the types of gears that operate on parallel shafts, intersecting shafts, and nonparallel and nonintersecting shafts. Next, the processes involved in the selection of gear are discussed, followed by information on the basic stresses applied to a gear tooth, the strength of a gear tooth, and the most widely used gear materials. Further, the chapter briefly reviews gear manufacturing methods and the heat treating processing steps including prehardening processes, through hardening, and case hardening processes.

A General Method for Computing Worm Gear Conjugate Mesh Property: Part 2—The Mathematic Model of Worm Gear Manufacturing and Working Processes

1989 ◽  
Vol 111 (1) ◽  
pp. 148-152 ◽  
Author(s):  
Changqi Zheng ◽  
Jirong Lei
Keyword(s):  
Contact Line ◽  
Relative Velocity ◽  
Velocity Vector ◽  
Gear Tooth ◽  
Mathematic Model ◽  
Worm Gear ◽  
Tooth Surface ◽  
Gear Manufacturing ◽  
General Method ◽  
Working Processes

Part 2 of this article is devoted to building a generalized mathematic model of worm gear manufacturing and working processes which can be used for calculating the contact line, the profile, the normal curvature, the conjugate boundary and the angle between the directions of contact line and relative velocity vector for any kind of worm gear tooth surface.

F-0323 Countermeasures of Inclusion of Chips on Gear Tooth Surface during : High-speed Dry Hobbing

2001 ◽  
Vol III.01.1 (0) ◽  
pp. 147-148
Author(s):  
Isao SAKURAGI ◽  
Yasuhiro OCHI ◽  
Masao KAWATA ◽  
Masaaki NISHIOKA ◽  
Masataka YONEKURA ◽  
...  
Keyword(s):  
High Speed ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Dry Hobbing

Quality Control Method Based on Gear Tooth Contact Evaluation Using Near-Infrared Ray Imagery

2010 ◽  
Vol 447-448 ◽  
pp. 569-573
Author(s):  
Masaki Nagata ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Takahiro Iida ◽  
Yasuhiro Uenishi ◽  
...  
Keyword(s):  
Contact Area ◽  
Near Infrared ◽  
Control Method ◽  
Gear Tooth ◽  
Scattered Light ◽  
Infrared Image ◽  
Tooth Surface ◽  
Image Method ◽  
Tooth Contact ◽  
Gear Manufacturing

Conventionally, tooth contact evaluation has been performed visually by machine operators in gear manufacturing fields when finishing a gear or during assembly. With automation, the contact area’s boundary is unclear due to scattered light when visible light is used to obtain an image for tooth contact evaluation. We therefore focused on using near-infrared to prevent scattered light. First, we confirmed that the tooth contact image obtained by image binarization is hardly affected by the image threshold. Second, we propose a new method to extract the boundary part of the tooth contact by differential calculation of the fine near-infrared image. These methods allow automatic division of near-infrared images into the contact area, the boundary, and the non-contact area. Finally, the obtained result is compared with the tooth contact calculated from the measured tooth surface. We demonstrated that the near-infrared image method is effective for automatic tooth contact evaluation.

scholarly journals Elastohydrodynamic Lubrication Characteristics of Spiral Bevel Gear Subjected to Shot Peening Treatment

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Shuai Mo ◽  
Ting Zhang ◽  
Guoguang Jin ◽  
Shengping Zhu ◽  
Jiabei Gong ◽  
...  
Keyword(s):  
Shot Peening ◽  
High Speed ◽  
Bending Strength ◽  
Elastohydrodynamic Lubrication ◽  
Bevel Gear ◽  
Tooth Surface ◽  
Spiral Bevel Gear ◽  
Heavy Load ◽  
Spiral Bevel ◽  
Lubrication Characteristics

High speed and heavy load put forward demanding requirements for the bending strength of spiral bevel gear. Shot peening, as a technological method, can greatly improve the bending strength of gear. During shot peening, a large number of subtle projectiles bombard the tooth surface of spiral bevel gear at an extremely high speed, which makes the latter produce plastic deformation and strengthened layer. Serving as the bombarded target, spiral bevel gear inevitably leads to the change of tooth surfaces microstructure. This paper aims at revealing the coupling law between microstructure and lubrication characteristics and establishing a reasonable model that can describe the tooth surface microstructure of shot peened spiral bevel gear. Besides, this paper brings insight into the lubrication characteristics of shot peened spiral bevel gears. Based on the elastohydrodynamic lubrication (EHL) theory, a comparative research on tooth surface lubrication characteristics has been conducted by various microscopic morphologies in this study.

A Virtual Tool for Wear Simulation of Standard and Non-Standard Spur Gears

2012 ◽  
Author(s):  
F. Karpat ◽  
S. Ekwaro-Osire ◽  
E. Karpat
Keyword(s):  
High Speed ◽  
High Performance ◽  
Failure Modes ◽  
Power Transmission ◽  
Wear Behavior ◽  
Gear Tooth ◽  
Load Capacity ◽  
High Load ◽  
Wear Depth ◽  
Spur Gears

There is an industrial demand for the increased performance of mechanical power transmission devices. This need in high performance is driven by high load capacity, high endurance, low cost, long life, and high speed. New designs and modifications in gears have been investigated to obtain high load carrying capacity and increased life with less volume and weight. Tooth wear is one of the major failure modes in gears. Although there are different classifications of wear mechanisms, wear on gears can be simply classified as mild wear, pitting, and severe wear, depending on the wear rate. These types of wear may lead to power transmission losses, decreased efficiency, increased vibration and noise, and gear tooth failure. This paper deals with the simulation of wear for standard and non-standard gears using an analytical approach. A numerical model for wear prediction of gear pair is developed. A wear model based on Archard’s equation is employed to predict wear depth. A MATLAB-based virtual tool is developed to analyze wear behavior of standard and non-standard spur gears with various gear parameters. In this paper, this virtual tool is introduced by using many numerical examples.

Development of a Dynamometer to Study the Performance of Plastic Gears

2007 ◽  
Author(s):  
Mike Cassata ◽  
Martin Morris ◽  
Jorge Abanto-Bueno
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Gear Tooth ◽  
Digital Camera ◽  
Operating Conditions ◽  
Spur Gears ◽  
Camera System ◽  
Dupont Company ◽  
Plastic Gears ◽  
Flank Surface

A testing facility has been developed to explore the failure modes of plastic gears. The overall goal is the prediction of gear tooth failure for a given set of operating conditions and to classify failure modes of plastic gears. The initial investigation is centered on the testing of plastic spur gears placed on a parallel-shaft drive train between a variable-speed, reversible DC motor and an eddy current dynamometer. The testing apparatus has been designed, fabricated, and refined to deliver consistent results. The dynamometer places two plastic spur gears in mesh, one being the drive gear and the other the driven. Most of the test gear pairs were injection molded, 40-tooth, 0.8 module gears. These gears were molded using Delrin™ 311DP, a polyoxymethylene polymer which is made by the DuPont Company. Optical encoders were attached to the input and output shafts to sense the shaft position providing a measurement of the deflection and wear of the gear teeth. In addition, an infrared temperature sensor was retrofitted to the dynamometer apparatus to measure the tooth-flank surface temperature. All of the tests where the gear flank temperature reached 250°F resulted in a catastrophic failure. The apparatus was also fitted with a high-speed digital camera system capable of sampling 1000 frames per second. The camera recorded the failure of the plastic gears.

Analysis of Micro-Elastohydrodynamic Lubrication and Prediction of Surface Fatigue Damage in Micropitting Tests on Helical Gears

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
H. P. Evans ◽  
R. W. Snidle ◽  
K. J. Sharif ◽  
B. A. Shaw ◽  
J. Zhang
Keyword(s):  
Damage Accumulation ◽  
Gear Tooth ◽  
Contact Fatigue ◽  
Elastohydrodynamic Lubrication ◽  
Tooth Surface ◽  
Asperity Contact ◽  
Surface Fatigue ◽  
Tooth Surfaces ◽  
Surface Profiles ◽  
Alternative Processes

The paper describes results obtained from the micro-elastohydrodynamic lubrication (micro-EHL) modeling of the gear tooth contacts used in micropitting tests together with a contact fatigue and damage accumulation analysis of the surfaces involved. Tooth surface profiles were acquired from pairs of helical test gears and micro-EHL simulations were performed corresponding to surfaces that actually came into contact during the meshing cycle. Plane strain fatigue and damage accumulation analysis shows that the predicted damage is concentrated close to the tooth surfaces and this supports the view that micropitting arises from fatigue at the asperity contact level. A comparison of the micropitting performance of gears finish-ground by two alternative processes (generation-grinding and form-grinding) suggests that 3D “waviness” may be an important factor in explaining their different micropitting behavior.

209 Possibility of High Speed Finishing of Hard Gear Tooth Surface with cBN-Tipped Hob

2007 ◽  
Vol 2007 (0) ◽  
pp. 145-148
Author(s):  
Yoji UMEZAKI ◽  
Yasutsune ARIURA ◽  
Toshio SUZUKI ◽  
Ryohei ISHIMARU
Keyword(s):  
High Speed ◽  
Gear Tooth ◽  
Tooth Surface
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