Download or read book An Experimental Study on the Effects of Debris Damage on Scuffing Performance of Spur Gear Pairs written by Tiffany Wen Roe Lim and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, a test methodology was developed to induce debris to the gear tooth profiles during the operation of a gear pair. This methodology was applied to a number of spur gear specimens for different types, quantities and sizes of debris particles. The extent of surface damage due to application of debris was documented and related to the sizes, types and quantities of debris applied. A high-speed and high-temperature test machine was used to put gears with varying severity of debris damage through a staged scuffing test to investigate the influence of such damage on scuffing outcome. While selected damage sites monitored during staged scuffing tests did not exhibit any progression to be identified as initiation sites for scuffing failure, gears with no or little debris damage were shown to pass the scuffing test while gears with heavier debris damage scuffed consistently. As such, the results of this study show conclusively that there is a direct correlation between severity of the debris damage and resultant scuffing performance of the gears.
Download or read book An Experimental Study on the Scuffing Performance of High power Spur Gears at Elevated Oil Temperatures written by James Walter Brenneman and published by . This book was released on 2013 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In this study, a number of spur gear tests were performed under high-power and high-temperature conditions representative of certain aerospace gearing applications. As the first type of tests, long cycle tests of 100 million cycles were performed at set operating speed, load, and temperature conditions. The second type of tests, load-staged scuffing tests, implemented an incrementally increased torque schedule under constant speed and oil temperature conditions. Two different gear tooth surfaces were considered in these tests: hard ground surfaces representative of rough, as machined gear surfaces and chemically polished gear surfaces that were an order of magnitude smoother than the ground surfaces. The primary failure mode of concern was scuffing of the contact surfaces due to temperature build up. The impact of surface roughness amplitudes, contact stress, and oil inlet temperature on scuffing failures were investigated. Effects of ramp up procedures for the speed and torque, as well as the introduction of a break-in test stage were also investigated to show that they are critical to the scuffing performance of gears.
Download or read book The Influence of a Class of Surface Defects on the High speed Scuffing Performance of Spur Gears written by Gunther Shepard Beall and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gear teeth experience contact conditions that vary continuously as they pass through the meshing zone. Thus, not only the sizes but also the positions of surface defects become critical to their scuffing survivability. High-speed gearbox cost and reliability can be improved by quantifying these features and determining their impact on scuffing performance. Pursuant to this, representative defects in the form of scratches are applied in two batches to the contacting surfaces of high-quality spur gear specimens. These, along with an undamaged baseline gear pair, are then tested through a staged scuffing matrix incrementally increasing the operating load, speed, and lubricant temperature. Metrological procedures developed to quantify scratch parameters and track surface damage are used initially and throughout testing to document evolvement of the surfaces. It is concluded that (i) larger scratches generally decrease scuffing performance, (ii) the location of scratches is critical to scuffing performance; scuffing was never observed in areas where sliding velocities were low, (iii) increased wear and heat generation are observed on defects in high-sliding regions, and (iv) wear and tribo-film formation improve the scuffing performance of scratched gears. In addition, thermal elastohydrodynamic lubrication simulations are performed to confirm that increasing scratch width and surface sliding velocities have the most influence on increasing the lubricant flash temperatures.
Download or read book Gear Damage Detection Using Oil Debris Analysis written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this paper was to verify, when using an oil debris sensor, that accumulated mass predicts gear pitting damage and to identify a method to set threshold limits for damaged gears. Oil debris data was collected from 8 experiments with no damage and 8 with pitting damage in the NASA Glenn Spur Gear Fatigue Rig. Oil debris feature analysis was performed on this data. Video images of damage progression were also collected from 6 of the experiments with pitting damage. During each test, data from an oil debris sensor was monitored and recorded for the occurrence of pitting damage. The data measured from the oil debris sensor during experiments with damage and with no damage was used to identify membership functions to build a simple fuzzy logic model. Using fuzzy logic techniques and the oil debris data, threshold limits were defined that discriminate between stages of pitting wear. Results indicate accumulated mass combined with fuzzy logic analysis techniques is a good predictor of pitting damage on spur gears. Dempsey, Paula J. Glenn Research Center NASA/TM-2001-210936, E-12789, NAS 1.15:210936
Download or read book Integrating Oil Debris and Vibration Gear Damage Detection Technologies Using Fuzzy Logic written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: A diagnostic tool for detecting damage to spur gears was developed. Two different measurement technologies, wear debris analysis and vibration, were integrated into a health monitoring system for detecting surface fatigue pitting damage on gears. This integrated system showed improved detection and decision-making capabilities as compared to using individual measurement technologies. This diagnostic tool was developed and evaluated experimentally by collecting vibration and oil debris data from fatigue tests performed in the NASA Glenn Spur Gear Fatigue Test Rig. Experimental data were collected during experiments performed in this test rig with and without pitting. Results show combining the two measurement technologies improves the detection of pitting damage on spur gears. Dempsey, Paula J. and Afjeh, Abdollah A. Glenn Research Center NASA/TM-2002-211126, NAS 1.15:211126, E-12976
Download or read book An Experimental Study of the Impact of Various Tooth Surface Treatments on Spur Gear Pitting Life written by Jeremy Micah Bluestein and published by . This book was released on 2007 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In this study, the influence of various engineered surface treatments on the contact fatigue behavior of spur gear pairs was investigated, focusing on pitting life. A number of standard gear durability test machines were furbished and sets of specially designed spur gear test specimens were procured to execute a test matrix that includes gears having various surface treatments. Typical hobbed-shaved surfaces were considered to represent the baseline surface treatment and their pitting lives were compared to lives of gears having (i) chemically polished, (ii) shot-peened and plastic honed, and (iii) chemically polished and CrN coated surfaces. Pitting life of each variation was quantified at several stress levels by using a set of predetermined failure criteria, and test and inspection procedures. The data for each variation was processed statistically and compared to data from other surface variations. The results indicate that chemically polishing increases the pitting life of spur gears nearly three times over the life of the baseline hobbed-shaved gears. It was also observed that the shot-peened and plastic honed gears did not deliver any tangible pitting life improvements over the baseline conditions. Finally, a slight increase in pitting life was observed over chemically polished gears with the application of the CrN coating.
Download or read book An Experimental Investigation of the Impact of Engineered Surface Processes on Efficiency of Spur Gears written by Kreteeka Chaudhury and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was conducted to evaluate the effect of surface finish on spur gear power losses under jet lubrication. Four different surface finish combinations were tested: (i) hard ground surface pair, (ii) chemically polished surface pair, (iii) super honed surface pair and (iv) hard ground against chemically polished surface pair. The test was conducted at 432 different operating condition combinations of speed, torque, lubricant type and inlet temperature. An FZG back-to-back set up was used to conduct the test. Surface roughness inspections were carried out at regular intervals to monitor any changes in surface roughness characteristics. The measured power losses were resolved into spin (load independent) and mechanical (load dependent) power losses. The relation between both losses and various operating conditions were explored. As expected, spin power loss did not vary with variation in surface finish. Mechanical power loss increased with increase in speed and torque. Various surface roughness and operating parameters such as BAC curves and lambda ratio were calculated for each surface finish combination to study their correlation to power losses measured. For smoother surfaces, an increase in temperature decreased power loss as the viscosity of the lubricant decreased and hence rolling friction losses dominating the mechanical power loss decreased. However, for rougher surfaces sliding friction losses seemed to be dominant due to high amounts of asperity contact. Thus, more cases of higher power loss at high temperatures were observed for rougher surfaces.
Download or read book An Experimental Investigation of the Effect of Spacing Errors on the Loaded Transmission Error of Spur Gear Pairs written by Brian Anichowski (Jr.) and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper complements recent investigations [Handschuh et al. (2014), Talbot et al. (2016)] of the influences of tooth indexing errors on dynamic factors of spur gears by presenting data on changes to the dynamic transmission error. An experimental study is performed using an accelerometer-based dynamic transmission error measurement system incorporated into a high-speed gear tester to establish baseline dynamic behavior of gears having negligible indexing errors, and to characterize changes to this baseline due to application of tightly-controlled intentional indexing errors. Spur gears having different forms of indexing errors are paired with a gear having negligible indexing error. Dynamic transmission error of gear pairs under these error conditions is measured and examined in both time and frequency domains to quantify the transient effects induced by these indexing errors. These measurements are then compared against the baseline, no error condition, as a means to quantify the dynamic vibratory behavior induced due to the tooth indexing errors. These comparisons between measurements indicate clearly that the baseline dynamic response, dominated by well-defined resonance peaks and mesh harmonics, are complemented by non-mesh orders of transmission error due the transient behavior induced by indexing errors. In addition, the tooth (or teeth) having indexing error imparts transient effects which dominate the vibratory response of the system for significantly more mesh cycles than the teeth having errors are in contact. For this reason, along with the results presented in Talbot et al. (2016), it was concluded that spur gears containing indexing errors exhibit significant deviations from nominal behavior, at both a system and time-domain level.
Download or read book An Experimental Study of the Dynamic Response of Spur Gears Having Tooth Index Errors written by Allen Y. Sun and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While there are numerous theoretical and experimental investigations of dynamic behavior of gear pairs of higher quality grades, very little is known about the same when certain classes of manufacturing errors are present. This study aims at investigating the effects of tooth index errors, one of the most common types of manufacturing errors. Using the changes in stresses along the tooth root regions as the metric, an experimental study is executed here to (i) establish a baseline dynamic behavior under no tangible index error and (ii) characterize the changes caused by tightly-controlled intentional index errors to this baseline dynamic behavior. For this, various gears having different forms of index errors are paired with an instrumented gear having no such errors. For each gear pair, tests are performed within wide ranges of torque and speed. A data processing scheme is proposed to normalize the measured stress signals to multiplication factor. It is shown that the baseline dynamic response represented solely by the dynamic stress factor is altered significantly by transient vibrations induced by the indexing errors, in some cases fully altering the baseline dynamic behavior and increasing the stress multiplication factors significantly. The experimental database formed in this study is expected to guide much needed theoretical studies on this topic.
Download or read book Experimental Investigation of Spur Gear Efficiency and the Development of a Helical Gear Efficiency Test Machine written by Michael Daniel Moorhead and published by . This book was released on 2007 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Gear and transmission efficiency is one of the major issues in the automotive and aerospace industries. Both fuel economy and emission characteristics of vehicles are influenced by the efficiency of the drive trains and transmissions. The literature on gear efficiency is limited to few models. Accuracy of these models was not demonstrated, mainly due to the lack of experimental data, especially under high-speed conditions. Recent experiments by Chase [1] and Petry-Johnson [2] provided an extensive set of experimental data on efficiency for unity-ratio, precision spur gears operating at high- power conditions, representing racing applications. This experimental database was instrumental in validating the efficiency model of Xu, et al [3] for spur gears. This study presents experiments with the aim of extending this jet-lubricated spur gear efficiency database to non-unity ratio, production quality gear pairs having various surface treatments and operating with different lubricants under typical passenger vehicle conditions. As a separate study, it also provides a complete spin loss database for unity-ratio gears operating under dip-lubricated conditions. Direct comparisons between the two lubrication methods are also presented. Lastly, details of a design study for development of a test machine for efficiency measurements for helical gears is presented.
Download or read book Investigation of Gear and Bearing Fatigue Damage Using Debris Particle Distributions written by Paula J. Dempsey and published by BiblioGov. This book was released on 2013-07 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: A diagnostic tool was developed for detecting fatigue damage to spur gears, spiral bevel gears, and rolling element bearings. This diagnostic tool was developed and evaluated experimentally by collecting oil debris data from fatigue tests performed in the NASA Glenn Spur Gear Fatigue Rig, Spiral Bevel Gear Test Facility, and the 500hp Helicopter Transmission Test Stand. During each test, data from an online, in-line, inductance type oil debris sensor was monitored and recorded for the occurrence of pitting damage. Results indicate oil debris alone cannot discriminate between bearing and gear fatigue damage.
Download or read book Investigation of Gear and Bearing Fatigue Damage Using Debris Particle Distributions written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A diagnostic tool was developed for detecting fatigue damage to spur gears, spiral bevel gears, and rolling element bearings. This diagnostic tool was developed and evaluated experimentally by collecting oil debris data from fatigue tests performed in the NASA Glenn Spur Gear Fatigue Rig, Spiral Bevel Gear Test Facility, and the 500hp Helicopter Transmission Test Stand. During each test, data from an online, in-line, inductance type oil debris sensor was monitored and recorded for the occurrence of pitting damage. Results indicate oil debris alone cannot discriminate between bearing and gear fatigue damage. Dempsey, Paula J. and Lewicki, David G. and Decker, Harry J. Glenn Research Center NASA/TM-2004-212883, ARL-TR-3133, E-14297
Download or read book An Experimental Investigation of the Impact of Random Spacing Errors on the Transmission Error of Spur and Helical Gear Pairs written by Muhammad Nevin Anandika and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise and vibration performance of a gear system is critical in any industry. Vibrations caused by the excitations at the gear meshes propagate to the transmission housing to cause noise, while also increasing gear tooth stresses to degrade durability. As such, gear engineers must seek gear designs that are nominally quiet with low vibration amplitudes. tudes. They must also ensure that this nominal performance is robust in the presence of various manufacturing errors. This thesis research aims at an experimental investigation of the influence of one type of manufacturing error, namely random tooth spacing errors, on the vibratory responses of spur and helical gear pairs. For this purpose, families of spur and helical gear test specimens having intentionally induced, tightly controlled random spacing error sequences are fabricated. These specimens are paired and assembled in various ways to achieve different sequences of composite spacing errors. Static and dynamic motion transmission error measurements from these tests are compared to the baseline case of “no error” gear to quantify the impact of random spacing errors on the dynamic response. These comparisons show that there is a significant, quantifiable impact of random spacing errors on both spur and helical gear dynamics. In general, vibration amplitudes of gear pairs having random spacing errors are higher than those of the corresponding no-error gear pairs. In the frequency domain, gears having random spacing errors exhibit broad-band spectra with significant non-mesh harmonics, pointing to potential noise quality issues.
Download or read book A Comparative Study of the Impact of Dip and Jet Lubrication Methods on Spur Gear Contact Fatigue and Efficiency written by Jeremy C. Moss and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of spur gear efficiency is conducted under various jet-lubricated and dip-lubricated conditions. A test methodology is developed to measure load-independent (spin) and load-dependent (mechanical) losses to a gearbox containing a single spur gear pair. An experimental test matrix is defined to study the influence that the lubrication method has on these losses. The test matrix includes two dip-lubricated conditions that vary in submersion level of the gear pair, and four jet-lubricated conditions that vary in the gear mesh target location and velocity of the oil. Results indicate that the spin power losses are impacted by the lubrication method significantly while the mechanical losses are not influenced. An investigation of spur gear contact fatigue is conducted under several lubrication schemes from the efficiency study. A test methodology is developed to evaluate variations in tooth geometry due to surface wear, roughness, and pitting life. Pitting lives under each lubrication method are analyzed statistically to quantify any meaningful differences in gear pitting life. Results indicate that contact fatigue lives from jet-lubricated tests are as high as dip-lubricated ones as long as jet velocities are sufficient.
Download or read book An Experimental Methodology for Evaluating Root Stresses of Rattling Gear Pairs written by Colton W. Thomas and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gear rattle is a major noise problem in certain powertrains where an internal combustion engine drives a timing gear drive or a manual transmission. It is primarily a result of gear teeth losing contact intermittently and committing impacts along the drive and coast sides of the gear pair having a certain amount of backlash. Most of the studies on gear rattle focused on the noise and vibration aspects of the problem, with a very little attention given to adverse durability consequences. In this study, an experimental investigation is performed to measure root stresses while a pair of spur gears are in various types of rattling motions. A test setup is employed to operate a pair of high-accuracy spur gears under the influence of a periodically time varying input torque to produce periodic and non-periodic rattling motions. A multi-channel strain measurement system is incorporated in a methodology to measure root stresses in the instances of impact events. Changes to root stress time histories due to drive and coast-side impacts are documented to show that impacts significantly increase the root stress amplitudes and frequencies. The resultant experimental database generated under tightly-controlled conditions is suitable for validating future modeling studies that are required to predict statistical distributions for root stress duty cycles of gear teeth.
Download or read book Experimental Investigation of Spur Gear Efficiency written by Travis T. Petry-Johnson and published by . This book was released on 2007 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: An experimental investigation of high-speed spur gear efficiency was conducted for both jet-lubricated, dry sump conditions and dip-lubricated conditions. Inspection methodologies were developed for the documentation of gear surface roughness and wear after each test. An experimental test matrix including gears of two different modules and surface roughness levels operating under jet-lubrication conditions with four different gear lubricants was developed to quantify the influence of these parameters on load- dependent (mechanical) and load-independent (spin) power losses. The spur gear efficiency test machine was modified for dip-lubricated load independent power loss measurements, allowing direct comparison to jet-lubricated conditions using the same test fixtures. An experimental test matrix including unity ratio gears of different module and face width operating in an oil bath of four different levels for a range of rotational speed and oil viscosity was developed. The influence of rotational speed, oil viscosity, oil bath level, and rotational direction on load independent power loss was quantified.
Download or read book An Investigation of the Influence of Micropitting on the Progression of Gear Surface Pitting written by Eunsung Kim and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the progression of micropitting and its effect on the fatigue life of a spur gear is investigated through an experimental study. Standard contact durability testing is performed on two test gears and an inspection is done throughout the gear's life cycle. Operating conditions for the test are closely controlled to minimize the effect of applied load, lubrication conditions, shaft rotation speed, and temperature on the micropitting behavior. Gear tooth topography is captured using a gear specific CMM and roughness measurement is obtained using a profilometer. Macroscopic images are also taken to have a record of the physical appearance of the gear flank. Using the experimental data, the severity of surface degradation due to micropitting is quantified by measuring the maximum profile deviation from the initial state. Gear tooth surface topography is used in a load distribution prediction. The change in contact stress distribution and maximum contact stress location are compared to the gear tooth surface topography over the life of the gear to study the effect of micropitting. Contact stress data is then applied to a multi-axial fatigue damage model using the critical plane approach to calculate the fatigue damage parameter. The critical plane is determined by testing which candidate plane produces the maximum shear strain amplitude. Stress and strain components on this critical plane are then applied to the fatigue damage model to calculate the predicted number of cycles to failure, and a damage accumulation rule is employed to predict crack initiation. The maximum accumulated damage location closely aligned with the maximum contact stress location as well as the maximum critical-plane shear strain location. Most importantly, these locations corresponded to the pitting location. Based on the experimental and modelled results, micropitting significantly influences the contact stress distribution that leads to stress concentration, potentially leading to contact fatigue failure such as pitting. The fatigue damage prediction model is somewhat validated through the minimal experimental data further experimental data is needed to develop a method of predicting pitting initiation accurately.
