scholarly journals A Novel Tooth Tip Relief Method for Reducing Micro-Pitting of Spur Gears

2021 ◽  
Author(s):  
Xiangyang Xu ◽  
Yinghua Liang ◽  
Shumiao Zuo ◽  
Peng Dong ◽  
Yanfang Liu ◽  
...  
Keyword(s):  
Contact Stress ◽  
Smooth Transition ◽  
Curvature Radius ◽  
Spur Gears ◽  
The Novel ◽  
Hertz Contact ◽  
Bench Tests ◽  
Novel Method ◽  
Tooth Flank ◽  
Transition Areas

Abstract Micro-pitting is a common fatigue failure mode of spur gears. To reduce it, this paper proposes a novel tooth tip relief method. Gear meshing simulation is firstly performed considering the actual contact path, showing that there are four Hertz contact stress peaks in the transition areas of the tooth flank. Equations are then developed for the novel tooth tip relief method: one focuses on the smooth transition between the involute profile and the tip relief region, the other on the smooth transition between the tip relief region and the tooth tip. The results of curvature radius and Hertz contact stress show that the proposed novel method can effectively reduce the Hertz contact stress peaks, which indicates this tip relief method could benefit for reducing the micro-pitting. Finally, both wear simulations and bench tests are conducted, verifying the effectiveness of the proposed method for reducing the micro-pitting of spur gears.

scholarly journals A novel tooth tip relief method for reducing micro-pitting of spur gears

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110446
Author(s):  
Xiangyang Xu ◽  
Yinghua Liang ◽  
Shumiao Zuo ◽  
Peter Tenberge ◽  
Peng Dong ◽  
...  
Keyword(s):  
Contact Stress ◽  
Smooth Transition ◽  
Curvature Radius ◽  
Spur Gears ◽  
The Novel ◽  
Hertz Contact ◽  
Bench Tests ◽  
Novel Method ◽  
Tooth Flank ◽  
Transition Areas

Micro-pitting is a common fatigue failure mode of spur gears. To reduce it, this paper proposes a novel tooth tip relief method. Gear meshing simulation is firstly performed considering the actual contact path, showing that there are four Hertz contact stress peaks in the transition areas of the tooth flank. Equations are then developed for the novel tooth tip relief method: one focuses on the smooth transition between the involute profile and the tip relief region, the other on the smooth transition between the tip relief region and the tooth tip. The results of curvature radius and Hertz contact stress show that the proposed novel method can effectively reduce the Hertz contact stress peaks, which indicates this tip relief method could benefit for reducing the micro-pitting. Finally, both wear simulations and bench tests are conducted, verifying the effectiveness of the proposed method for reducing the micro-pitting of spur gears.

Simplified Spur Gear Design

2016 ◽  
Author(s):  
Edward E. Osakue
Keyword(s):  
Contact Stress ◽  
Design Method ◽  
Spur Gear ◽  
Load Factor ◽  
Spur Gears ◽  
Bending Stress ◽  
Hertz Contact ◽  
Gear Design ◽  
Simplified Method ◽  
The Difference

A simplified design method (SDM) for spur gears is presented. The Hertz contact stress and Lewis root bending stress capacity models for spur gears have been reformulated and formatted into simplified forms. A scheme is suggested for estimating the AGMA J-factor in Lewis root bending stress for spur gears from a single curve for both pinion and gear instead of the conventional two curves. A service load factor is introduced in gear design that accounts for different conventional rated load modifier factors. It represents a magnification factor for the rated load in a gear design problem. Two design examples are considered for applications of the stress capacity models. In Example 1, the Hertz contact stress of the SDM deviates from AGMA value by 1.95%. The variance in Example 2 between the contact stress of the SDM and FEM is 1.184% while that between SDM and AGMA is 0.09%. The root bending stress of AGMA and SDM for the pinion in Example 1 differs by 1.44% and that for the gear by 6.59%. The difference between the root bending stress of AGMA and SDM for pinion and gear in Example 2 is 0.18%. These examples suggest that the new simplified method gives results that compare very favorably with both AGMA and FEM solutions. The simplified method developed is recommended mainly for preliminary design when quick but reliable solutions are sought.

scholarly journals Experimental and Analytical Load-Life Relation for AISI 9310 Steel Spur Gears

1978 ◽  
Vol 100 (1) ◽  
pp. 54-60 ◽  
Author(s):  
D. P. Townsend ◽  
J. J. Coy ◽  
E. V. Zaretsky
Keyword(s):  
Test Data ◽  
Contact Stress ◽  
Vacuum Arc ◽  
Spur Gears ◽  
Hertz Contact ◽  
Average Value ◽  
Life Tests

Life tests were conducted at three different loads with three groups of 8.9 cm (3.5 in.) pitch diameter spur gears made of vacuum arc remelted (VAR) AISI 9310 steel. Life was found to vary inversely with load to the 4.3 and 5.1 power at the L10 and L50 life levels, respectively. The Weibull slope varied linearly with maximum Hertz contact stress, having an average value of 2.5. The test data when compared to AGMA standards showed a steeper slope for the load-life diagram.

Theoretical research on the wear characteristics of rotors in a twin-screw compressor

2021 ◽  
pp. 095440892110436
Author(s):  
Chuang Wang ◽  
Ziwen Xing ◽  
Shizhong Sun ◽  
Wenqing Chen ◽  
Zhilong He
Keyword(s):  
Wear Resistance ◽  
Film Thickness ◽  
Contact Stress ◽  
Contact Analysis ◽  
Theoretical Research ◽  
Curvature Radius ◽  
Hertz Contact ◽  
Minimum Film Thickness ◽  
Twin Screw ◽  
Sliding Distance

Thanks to the development and application of coating technology and polymer rotor material, it is an inevitable trend to eliminate synchronous gear for water-injected and dry twin-screw compressors, especially running at a high speed, due to much power consumed by synchronous gears. However, it is not economical and reliable to rely only on coating or rotor material to enhance the wear resistance of rotor. This paper attempts to lighten the rotor wear in twin-screw compressors from the angle of setting driving belt. To achieve this goal, the contact analysis is carried out in this paper, taking the rotor profile of a developed water-lubricated twin-screw air compressor as an example. By the contact analysis, equivalent curvature radius, Hertz contact stress, sliding distance, the value of PH S, and the minimum film thickness of each mesh point on different tooth curve are calculated and discussed. The product of the Hertz contact stress and total sliding distance, PH S, and minimum film thickness are chosen as the evaluation indexes to estimate the wear resistance of all tooth curves. By comparing these indexes of each tooth curve, some suggestions about setting the driving belt are proposed.

A novel method for the determination of linting propensity of paper

TAPPI Journal ◽  
2012 ◽  
Vol 11 (10) ◽  
pp. 9-17
Author(s):  
ALESSANDRA GERLI ◽  
LEENDERT C. EIGENBROOD
Keyword(s):  
Ash Content ◽  
The Novel ◽  
Offset Printing ◽  
Excellent Correlation ◽  
End Conditions ◽  
Bottom Side ◽  
Novel Method ◽  
Total Fraction

A novel method was developed for the determination of linting propensity of paper based on printing with an IGT printability tester and image analysis of the printed strips. On average, the total fraction of the surface removed as lint during printing is 0.01%-0.1%. This value is lower than those reported in most laboratory printing tests, and more representative of commercial offset printing applications. Newsprint paper produced on a roll/blade former machine was evaluated for linting propensity using the novel method and also printed on a commercial coldset offset press. Laboratory and commercial printing results matched well, showing that linting was higher for the bottom side of paper than for the top side, and that linting could be reduced on both sides by application of a dry-strength additive. In a second case study, varying wet-end conditions were used on a hybrid former machine to produce four paper reels, with the goal of matching the low linting propensity of the paper produced on a machine with gap former configuration. We found that the retention program, by improving fiber fines retention, substantially reduced the linting propensity of the paper produced on the hybrid former machine. The papers were also printed on a commercial coldset offset press. An excellent correlation was found between the total lint area removed from the bottom side of the paper samples during laboratory printing and lint collected on halftone areas of the first upper printing unit after 45000 copies. Finally, the method was applied to determine the linting propensity of highly filled supercalendered paper produced on a hybrid former machine. In this case, the linting propensity of the bottom side of paper correlated with its ash content.

Meshing and Bearing Analysis of Nutation Drive with Face Gear

2020 ◽  
Vol 13 (4) ◽  
pp. 352-365
Author(s):  
Guangxin Wang ◽  
Lili Zhu ◽  
Peng Wang ◽  
Jia Deng
Keyword(s):  
Contact Stress ◽  
High Efficiency ◽  
Transmission Ratio ◽  
Contact Strength ◽  
Hertz Contact ◽  
Face Gear ◽  
Compact Structure ◽  
Gear Teeth ◽  
Gear Drive ◽  
Number Of Teeth

Background: Nutation drive is being extensively investigated due to its ability to achieve a high reduction ratio with a compact structure and the potential for low vibration, high efficiency and design flexibility. However, many problems including the difficulty to process the inner bevel gear, less number of teeth in engagement and not being suitable for high-power transmission have restricted its development. Objective: The purpose of this paper is to analyze the contact strength of a patent about a new nutation drive developed based on meshing between two face gears, which has the advantages of both face gear and nutation drive, including large transmission ratio, large coincidence, small size, compact structure and strong bearing capacity. Methods: Based on the meshing principle and basic structure of the nutation face gear drive, the contact strength of nutation face gear transmission is analyzed by the Hertz contact analysis method and FEM method. Results: The maximum stress values of nutation face gear teeth are compared by two methods, which verify the accuracy of Hertz contact analytical method in calculating the contact strength of nutation face gear teeth. Furthermore, nine groups of three-dimensional models for the nutation face gear drive with a transmission ratio of 52 and different cutter parameters are established. Conclusion: The study analyzes the contact stress of fixed and rotary face gears in meshing with planetary face gears, and obtains the distribution law of contact stress and the influence of the number of teeth and parameters of the cutter on the load-carrying capacity.

scholarly journals REMAXINT: a two-mode clustering-based method for statistical inference on two-way interaction

2021 ◽  
Author(s):  
Zaheer Ahmed ◽  
Alberto Cassese ◽  
Gerard van Breukelen ◽  
Jan Schepers
Keyword(s):  
Null Hypothesis ◽  
Type I Error ◽  
Type I ◽  
The Novel ◽  
Simulation Studies ◽  
Test Statistic ◽  
Clustering Model ◽  
Novel Method ◽  
Main Effects ◽  
Empirical Case Studies

AbstractWe present a novel method, REMAXINT, that captures the gist of two-way interaction in row by column (i.e., two-mode) data, with one observation per cell. REMAXINT is a probabilistic two-mode clustering model that yields two-mode partitions with maximal interaction between row and column clusters. For estimation of the parameters of REMAXINT, we maximize a conditional classification likelihood in which the random row (or column) main effects are conditioned out. For testing the null hypothesis of no interaction between row and column clusters, we propose a $$max-F$$ m a x - F test statistic and discuss its properties. We develop a Monte Carlo approach to obtain its sampling distribution under the null hypothesis. We evaluate the performance of the method through simulation studies. Specifically, for selected values of data size and (true) numbers of clusters, we obtain critical values of the $$max-F$$ m a x - F statistic, determine empirical Type I error rate of the proposed inferential procedure and study its power to reject the null hypothesis. Next, we show that the novel method is useful in a variety of applications by presenting two empirical case studies and end with some concluding remarks.

scholarly journals Interrogating the Egypto-Sudanic Arabic Connection

Languages ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 123
Author(s):  
Thomas A. Leddy-Cecere
Keyword(s):  
The Novel ◽  
Present Contribution ◽  
Phonological Processes ◽  
Verbal Inflection ◽  
Segmental Phonology ◽  
Language Data ◽  
History Of ◽  
Novel Method ◽  
Dialect Classification ◽  
Arabic Speaking

The Arabic dialectology literature repeatedly asserts the existence of a macro-level classificatory relationship binding the Arabic speech varieties of the combined Egypto-Sudanic area. This proposal, though oft-encountered, has not previously been formulated in reference to extensive linguistic criteria, but is instead framed primarily on the nonlinguistic premise of historical demographic and genealogical relationships joining the Arabic-speaking communities of the region. The present contribution provides a linguistically based evaluation of this proposed dialectal grouping, to assess whether the postulated dialectal unity is meaningfully borne out by available language data. Isoglosses from the domains of segmental phonology, phonological processes, pronominal morphology, verbal inflection, and syntax are analyzed across six dialects representing Arabic speech in the region. These are shown to offer minimal support for a unified Egypto-Sudanic dialect classification, but instead to indicate a significant north–south differentiation within the sample—a finding further qualified via application of the novel method of Historical Glottometry developed by François and Kalyan. The investigation concludes with reflection on the implications of these results on the understandings of the correspondence between linguistic and human genealogical relationships in the history of Arabic and in dialectological practice more broadly.

scholarly journals Suspended Sediment Modeling Using a Heuristic Regression Method Hybridized with Kmeans Clustering

2021 ◽  
Vol 13 (9) ◽  
pp. 4648
Author(s):  
Rana Muhammad Adnan ◽  
Kulwinder Singh Parmar ◽  
Salim Heddam ◽  
Shamsuddin Shahid ◽  
Ozgur Kisi
Keyword(s):  
Clustering Algorithm ◽  
Suspended Sediments ◽  
Ecological Impacts ◽  
Accurate Estimation ◽  
Data Sets ◽  
The Novel ◽  
Neuro Fuzzy ◽  
Adaptive Regression ◽  
Novel Method ◽  
Model Training

The accurate estimation of suspended sediments (SSs) carries significance in determining the volume of dam storage, river carrying capacity, pollution susceptibility, soil erosion potential, aquatic ecological impacts, and the design and operation of hydraulic structures. The presented study proposes a new method for accurately estimating daily SSs using antecedent discharge and sediment information. The novel method is developed by hybridizing the multivariate adaptive regression spline (MARS) and the Kmeans clustering algorithm (MARS–KM). The proposed method’s efficacy is established by comparing its performance with the adaptive neuro-fuzzy system (ANFIS), MARS, and M5 tree (M5Tree) models in predicting SSs at two stations situated on the Yangtze River of China, according to the three assessment measurements, RMSE, MAE, and NSE. Two modeling scenarios are employed; data are divided into 50–50% for model training and testing in the first scenario, and the training and test data sets are swapped in the second scenario. In Guangyuan Station, the MARS–KM showed a performance improvement compared to ANFIS, MARS, and M5Tree methods in term of RMSE by 39%, 30%, and 18% in the first scenario and by 24%, 22%, and 8% in the second scenario, respectively, while the improvement in RMSE of ANFIS, MARS, and M5Tree was 34%, 26%, and 27% in the first scenario and 7%, 16%, and 6% in the second scenario, respectively, at Beibei Station. Additionally, the MARS–KM models provided much more satisfactory estimates using only discharge values as inputs.

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