scholarly journals Wear of AlCrN and CrAlSiN Coatings Applied to Nonstandard Involute Gears

Lubricants ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 54
Author(s):  
Pavol Švec ◽  
Miroslav Bošanský ◽  
Ernest Gondár ◽  
František Toth ◽  
Roman Protasov
Keyword(s):  
Steel Substrate ◽  
Tooth Wear ◽  
Tooth Surface ◽  
Chemical Compositions ◽  
Frictional Stress ◽  
Critical Surface ◽  
Face Surface ◽  
Critical Weight ◽  
Involute Gears ◽  
Tooth Flank

Wear of nonstandard involute gears with two types of coatings, AlCrN and CrAlSiN, was studied. The coatings were applied by cathodic arc deposition. The gears were tested using a Niemann tester at a graduated load up to the 12th load stage and were compared to noncoated gears. Both Biogear S150 gear oil and PP90 universal hydraulic oil were applied during these tests. The thickness of deposited coatings and wear of gear teeth were studied by SEM and their chemical compositions were determined by EDS analysis. Maximal contact pressure of 1350 MPa was calculated in the region of the tooth flank at the 12th load stage. Maximal frictional stress was also calculated on the tooth flank. The resistance against wear of gears was evaluated based on the critical weight loss and mainly based on the critical surface roughness of gears. The critical roughness was exceeded at the 10th load stage for noncoated gears. For the gears with AlCrN and CrAlSiN coatings, the critical roughness was exceeded at the 11th load stage. Wear of AlCrN and CrAlSiN coatings was nonuniform along the height of tooth. Wear on the tooth flank was characterized by fragmentation of thin coatings and subsequent detaching of fragments from the steel substrate. The steel substrate was worn by microcutting, which caused the highest roughness on the tooth surface. On the tooth pitch, surface protrusions of coatings were smoothed, and coatings cracked and locally detached subsequently. On the tooth face, surface protrusions were also smoothed but coatings remained compact without crack initiations. Both experimental oils, Biogear S150 and PP90, proved to be suitable during Niemann tests as their temperatures did not exceed the limit value of 80 °C.

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.

scholarly journals Influence of tooth flank modification on tooth surface damage of conical involute gears

2015 ◽  
Vol 81 (829) ◽  
pp. 15-00311-15-00311 ◽  
Author(s):  
Kunihiko MORIKAWA ◽  
Kouji KUMAGAI ◽  
Mikio NAGAHARA ◽  
Masaharu KOMORI
Keyword(s):  
Surface Damage ◽  
Tooth Surface ◽  
Involute Gears ◽  
Tooth Flank

scholarly journals 2208 Influence of Tooth Flank Modification on Tooth Surface Damage of Conical Involute Gears

2013 ◽  
Vol 2013 (0) ◽  
pp. 293-297
Author(s):  
Kouji KUMAGAI ◽  
Kunihiko MORIKAWA ◽  
Mikio NAGAHARA ◽  
Masaharu KOMORI
Keyword(s):  
Surface Damage ◽  
Tooth Surface ◽  
Involute Gears ◽  
Tooth Flank

Influence of the backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set

2016 ◽  
Vol 231 (11) ◽  
pp. 2025-2041 ◽  
Author(s):  
Shijing Wu ◽  
Haibo Zhang ◽  
Xiaosun Wang ◽  
Zeming Peng ◽  
Kangkang Yang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Planetary Gear ◽  
Tooth Wear ◽  
Transmission Error ◽  
Gear Transmission ◽  
Tooth Surface ◽  
Contact Ratio ◽  
The Impact

Backlash is a key internal excitation on the dynamic response of planetary gear transmission. After the gear transmission running for a long time under load torque, due to tooth wear accumulation, the backlash between the tooth surface of two mating gears increases, which results in a larger and irregular backlash. However, the increasing backlash generated by tooth accumulated wear is generally neglected in lots of dynamics analysis for epicyclic gear trains. In order to investigate the impact of backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set, in this work, first a static tooth surface wear prediction model is incorporated with a dynamic iteration methodology to get the increasing backlash generated by tooth accumulated wear for one pair of mating teeth under the condition that contact ratio equals to one. Then in order to introduce the tooth accumulated wear into dynamic model of compound planetary gear set, the backlash excitation generated by tooth accumulated wear for each meshing pair in compound planetary gear set is given under the condition that contact ratio equals to one and does not equal to one. Last, in order to investigate the impact of the increasing backlash generated by tooth accumulated wear on dynamic response of compound planetary gear set, a nonlinear lumped-parameter dynamic model of compound planetary gear set is employed to describe the dynamic relationships of gear transmission under the internal excitations generated by worn profile, meshing stiffness, transmission error, and backlash. The results indicate that the introduction of the increasing backlash generated by tooth accumulated wear makes a significant influence on the bifurcation and chaotic characteristics, dynamic response in time domain, and load sharing behavior of compound planetary gear set.

On Satisfaction of the Fifth Necessary Condition of Proper Part Surface Generation in Design of Plunge Shaving Cutter for Finishing of Precision Involute Gears

2006 ◽  
Vol 129 (9) ◽  
pp. 969-980 ◽  
Author(s):  
Stephen P. Radzevich
Keyword(s):  
Gear Tooth ◽  
Numerical Control ◽  
Proper Part ◽  
Surface Generation ◽  
Tooth Surface ◽  
Necessary Condition ◽  
Analytical Mechanics ◽  
Part Surface ◽  
Involute Gears ◽  
Novel Design

In this paper, a novel modified scheme and effective computer representation for design of a plunge shaving cutter is presented. The paper aims to develop a novel design of shaving cutter for plunge shaving of precision involute gears. The study is carried out on the premise of satisfaction of the fifth necessary condition of proper part surface generation (PSG) when designing the plunge shaving cutter. In the current study, the author’s earlier developed DG/K method of surface generation is used together with the principal elements of analytical mechanics of gears. (The DG/K method is based on fundamental results obtained in differential geometry of surfaces, and on kinematics of multi-parametric motion of a rigid body in the E3 space. The interested reader may wish to go for details to the monograph: Radzevich, S.P., Fundamentals of Surface Generation, Monograph, Kiev, Rastan, 2001, 592 pp., and to: Radzevich, S.P., Sculptured Surface Machining on Multi-Axis NC Machine, Monograph, Kiev, Vishcha Schola, 1991, 192 pp.) In the particular case under consideration, the method employs (a) an analytical description of the gear tooth surface to be machined, (b) configuration of the plunge shaving cutter relative to the involute gear, (c) analytical representation of the coordinate systems transformations, and (d) the fifth condition of proper PSG that is adapted to finishing of precision involute gears. The fifth condition of proper PSG is investigated in the paper. On the premise of the obtained results of the investigation, a novel design of plunge shaving cutter for finishing of precision involute gears is proposed. The developed novel design of plunge shaving cutter can be used on shaving machines available on the market, e.g. on Gleason’s new Genesis™ 130SV computer numerical control (CNC) shaving machine.

A new geometry definition and generation method for a face gear meshed with a spur pinion

2021 ◽  
pp. 095440542110609
Author(s):  
Xian-Long Peng
Keyword(s):  
Ruled Surface ◽  
Tooth Surface ◽  
Face Gear ◽  
Absolute Deviation ◽  
Numerical Examples ◽  
Gear Teeth ◽  
The Face ◽  
Geometry Feature ◽  
Tooth Flank ◽  
Straight Lines

The conventional tooth surface of a face gear is difficult to manufacture, and the cutter for the face gear cutting is not uniform even though the parameters of the pinion mating with the face gear slightly change. Based on the analysis of the geometry features of the tooth surface, a new developable ruled surface is defined as the tooth flank of the face gear, for which the most important geometry feature is that the flank could be represented by a family of straight lines, hence it could be generated by a straight-edged cutter. The mathematical models of the new ruled tooth surface, the cutter and the generation method are presented, the deviation between the ruled surface and the conventional surface, the correction of the ruled surface to reduce the deviation are investigated through numerical examples. The manufacturing process is simulated by VERICUT software, and the results demonstrate that even when the principle deviation is added to the machined deviation, the absolute deviation is on the micro-scale. The meshing and contact simulation shows that the new surface could obtain good meshing performance when the number of face gear teeth is greater than three times the number of pinion teeth. This research provides a new method for manufacturing face gears.

scholarly journals A Critical Review of Modern Concepts for Teeth Whitening

2019 ◽  
Vol 7 (3) ◽  
pp. 79 ◽  
Author(s):  
Matthias Epple ◽  
Frederic Meyer ◽  
Joachim Enax
Keyword(s):  
Oral Care ◽  
Organic Matrix ◽  
Tooth Wear ◽  
Literature Survey ◽  
Tooth Surface ◽  
Controlled Clinical Trials ◽  
Organic Chromophores ◽  
Hydrophobic Compounds ◽  
Mechanical Removal

Besides prevention of caries and periodontitis, an increasing number of oral care products focus on teeth whitening. The aim of this review is to summarize and discuss frequently used whitening agents and their efficacy from a chemical viewpoint. Therefore, a comprehensive literature survey on teeth whitening agents and products was conducted. The current whitening methods are analyzed and discussed from a chemist’s viewpoint. Frequently used whitening agents are abrasives (mechanical removal of stains), antiredeposition agents (prevention of deposition of chromophores), colorants (intended to lead to a white color), proteases (degradation of proteins), peroxides (oxidation of organic chromophores), and surfactants (removal of hydrophobic compounds from tooth surface). In-office bleaching using peroxides is effective, but side effects like tooth sensitivity or a damage of the natural organic matrix of enamel and dentin may occur. The applicability of abrasives in teeth whitening is limited due to potential tooth wear, especially when toothpastes with high RDA values are used. The effect of other whitening agents in vivo is often unclear because of a shortage of placebo-controlled clinical trials.

Spiral involutes and their application in gear transmission

2011 ◽  
Vol 225 (12) ◽  
pp. 2981-2990 ◽  
Author(s):  
L Liu ◽  
Y H Huang
Keyword(s):  
Gear Transmission ◽  
Transmission Ratio ◽  
Tooth Surface ◽  
Helical Gears ◽  
Gear Drive ◽  
Uniform Velocity ◽  
Solid Models ◽  
Involute Gears ◽  
New Type ◽  
Cylindrical Spiral

Involute helical gears mesh based on the intersections of involute helicoids. However, spiral involutes on the tooth surface do not participate in meshing directly. A new type of gear drive, the spiral involute gear drive, is proposed that works on the contact of spiral involutes. The generation of tooth profile is introduced in detail. Through relative-stagnation method, spiral involutes prove to have conjugation characteristics. To testify whether the transmission ratio of cylindrical spiral involute gears is constant, simulation is implemented in commercial codes ADAMS based on solid models of a pair of spiral involute gears. The computed results show that this novel gear drive can achieve a constant transmission ratio. Due to transmission with uniform velocity, cylindrical spiral involute gears can be used in transmission between intersecting axes. Milling and grinding apply to manufacturing of spiral involute gears.

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