Wear and Mechanical Contact Behavior of Polymer Gears

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Khalid Abdulkhaliq M. Alharbi
Keyword(s):  
Wear Rate ◽  
Wear Mechanisms ◽  
Surface Profile ◽  
Mechanical Contact ◽  
Test Rig ◽  
Injection Molded ◽  
Polymer Fatigue ◽  
Manufacturing Techniques ◽  
Tooth Flank ◽  
Flank Surface

Extensive investigations have been carried out in the present paper to understand polymer gear performance, i.e., wear and contact behaviors. The experimental results and possible wear mechanisms for polymer gears run against themselves have been presented, especially the wear rate of the polymer gears under different running speeds and loads. The tested samples were made of three different materials (acetal, nylon, and polycarbonate (PC)) and the effects of two different manufacturing techniques were also investigated (i.e., machine-cut and injection-molded polymer gears). The polymer gear performances (wear and life) were recorded using a uniquely designed and built test rig for this purpose. The testing results have been compared with the existing literature for polymer fatigue and wear theory. Further extensive investigations have been carried out to understand the wear phenomena on tooth flank surface profile of these gears and the data obtained have been discussed.

Cutter Interchangeability for Spiral-Bevel and Hypoid Gear Manufacturing

2003 ◽  
Author(s):  
Claude Gosselin ◽  
Jack Masseth ◽  
Wei Liang
Keyword(s):  
Test Case ◽  
Hypoid Gear ◽  
Hypoid Gears ◽  
Manufacturing Operations ◽  
Before And After ◽  
Gear Manufacturing ◽  
Spiral Bevel ◽  
Tooth Flank ◽  
Tooth Flank Surface Topography ◽  
Flank Surface

In the manufacturing of spiral-bevel and hypoid gears, circular cutter dimensions are usually based on the desired performance of a gear set. In large manufacturing operations, where several hundred gear geometries may have been cut over the years, the necessary cutter inventory may become quite large since the cutter diameters will differ from one geometry to another, which results in used storage space and associated costs in purchasing and maintaining the cutter parts. Interchangeability of cutters is therefore of significant interest to reduce cost while maintaining approved tooth geometries. An algorithm is presented which allows the use of a different cutter, either in diameter and/or pressure angle, to obtain the same tooth flank surface topography. A test case is presented to illustrate the usefulness of the method: the OB cutter diameter of an hypoid pinion is changed from 8.9500" to 9.1000". CMM results and the comparison of the bearing patterns before and after change show excellent correlation, and indicate that the new pinion can be used in place of the original pinion without performance or quality problems. Significant cost reductions may be obtained with the application of the method.

Tribological and thermomechanical analysis of CaO (quicklime) particulates filled ZA-27 alloy composites for bearing application

2015 ◽  
Vol 232 (1) ◽  
pp. 20-34 ◽  
Author(s):  
Swati Gangwar ◽  
Amar Patnaik ◽  
IK Bhat
Keyword(s):  
Wear Rate ◽  
Normal Load ◽  
Energy Dispersive Spectrometer ◽  
Thermo Gravimetric Analysis ◽  
Research Work ◽  
Surface Profile ◽  
Specific Wear Rate ◽  
Gravimetric Analysis ◽  
Load Range ◽  
Environment Temperature

This research work investigates friction and wears behaviour of CaO filler / particulate reinforced ZA-27 alloy composites. Pin-on-disk tribometer confining to ASTM G 99 standard with EN-31 hardened steel disc was used to simulate the tribological performance experimentally. The tribological parameters were evaluated over a normal load range of 5–45 N, sliding velocity of 1.047–5.235 m/s., sliding distance of 500–2500 m, environment temperature of 25–45℃ and filler content range of 0–10 wt%. The various alloy composites were fabricated under vacuum environment by high-temperature gravity casting technique. The steady-state specific wear rate and coefficient of friction were evaluated under different boundary conditions and thereafter Taguchi design of experiment methodology was adopted to compute the experimental specific wear rate of the proposed alloy composites. The dynamic mechanical analysis and thermo-gravimetric analysis study were also performed in order to observe the thermal characteristics of the composites at higher temperature. Finally, the surface morphology of the worn samples was performed using field-emission scanning electron microscope to understand the wear mechanism prevailed at rubbing surfaces and then atomic force microscopy analysis was studied to evaluate the surface profile of the worn sample. At the end, energy-dispersive spectrometer analysis was also performed to find out the elemental compositions of the worn alloy composites.

Performance of Injection-Molded Plastic Helical Gears Finished by Hot Rolling

2011 ◽  
Author(s):  
Morimasa Nakamura ◽  
Atsushi Katayama ◽  
Ichiro Moriwaki
Keyword(s):  
Injection Molding ◽  
Hot Rolling ◽  
Load Capacity ◽  
Transmission Error ◽  
Tooth Profile ◽  
Test Rig ◽  
Helical Gears ◽  
Injection Molded ◽  
Injection Molded Plastic ◽  
Plastic Gears

A hot-roll finishing was proposed as a simple finishing method for plastic gears. In the hot-roll finishing, plastic work gears are finished by meshing with a heated copper die wheel. In the previous study, a hot-roll finishing rig for plastic gears was developed, and it was confirmed that tooth profiles of hobbed plastic gears are improved by the finishing. Thus, the hot-roll finishing could also be effective for injection-molded plastic gears. In the present paper, appropriate hot-roll finishing procedures for injection-molded polyoxymethylene (POM) helical gears were pursued. In the injection molding, an inadequate mold easily allows large slope deviations on a tooth profile and trace. The hot-roll finishing can reduce the slope deviations, but induces form deviations especially on the profile. Tests of injection-molded and hot-roll-finished plastic gears were performed on a self-produced gear roller test rig and a self-produced fatigue rig, and a transmission error and load capacity were estimated. Compared with injection-molded gears, hot-roll-finished plastic gears showed small transmission error, while a load capacity was at the almost same level. As a result, the hot-roll finishing is effective for improving a transmission error of injection-molded plastic gears.

Sliding Wear Behavior of a Duplex Stainless Steel

2009 ◽  
Vol 423 ◽  
pp. 125-130 ◽  
Author(s):  
Alvaro Mestra ◽  
Gemma Fargas ◽  
Marc Anglada ◽  
Antonio Mateo
Keyword(s):  
Stainless Steel ◽  
Wear Rate ◽  
Duplex Stainless Steel ◽  
Wear Mechanisms ◽  
Sliding Wear ◽  
Wear Behavior ◽  
Wear Behaviour ◽  
Sliding Velocity ◽  
Fatigue Wear ◽  
Sliding Distance

Duplex stainless steels contain similar amounts of austenite  and ferrite α. This two-phase microstructure leads to an excellent combination of mechanical properties and corrosion resistance. However, there are few works dealing with the wear behaviour of these steels. This paper aims to determine the sliding wear mechanisms of a duplex stainless steel type 2205. In order to do it, three different sliding velocities (0.2, 0.7 and 1.2 m/s) and six sliding distances (500, 1000, 2000, 3000, 4000 and 5000 m) were selected. The results show that wear rate depends on both sliding velocity and sliding distance. The wear mechanisms detected were plowing, microcracking and microcutting (typical mechanisms of fatigue wear). These mechanisms evolve according to sliding velocity and sliding distance, highlighting a transition zone in which wear rate is reduced.

Friction and Wear Behavior of Polypropylene/Montmorillonite Intercalated Nanocomposites

2011 ◽  
Vol 311-313 ◽  
pp. 92-95 ◽  
Author(s):  
Kui Chen ◽  
Tian Yun Zhang ◽  
Wei Wei
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Abrasive Wear ◽  
Wear Mechanisms ◽  
Mass Fraction ◽  
Friction And Wear ◽  
Adhesive Wear ◽  
Wear Behavior ◽  
Friction And Wear Behavior

Polypropylene/organo-montmorillonite (PP/OMMT) composites were investigated by XRD. Friction and wear behaviors of this composites sliding against GCr15 stainless steel were examined on M-2000 text rig in a ring-on-block configuration. Worn surfaces of PP and its composites were analyzed by SEM. The result shows that PP macromolecule chains have intercalated into OMMT layers and form intercalated nanocomposites. With the increase of mass fraction of OMMT, both wear rate and friction coefficient of composites first decrease then rise. With the increase of load, from 150 N, 200 N to 250 N, wear rate of composites increases, while friction coefficient reduces. The wear mechanisms of composites are connected with the content of OMMT. Composites were dominated by adhesive wear, abrasive wear and adhesive wear accompanied by abrasive wear respectively with the increase of OMMT content.

Tooth Flank Breakage: Influences on Subsurface Initiated Fatigue Failures of Case Hardened Gears

2013 ◽  
Author(s):  
Karsten Stahl ◽  
Bernd-Robert Höhn ◽  
Thomas Tobie
Keyword(s):  
Failure Mode ◽  
Fatigue Failure ◽  
Failure Modes ◽  
Calculation Model ◽  
Operating Conditions ◽  
Material Strength ◽  
Gear Design ◽  
Increased Risk ◽  
Tooth Flank ◽  
Flank Surface

Pitting and tooth root breakage are typical fatigue failure modes of case hardened gears. Both failure types are usually initiated at the surface or close to the surface. General trends in modern gear industry, such as improved gear design with adequate flank modifications, high-quality gear materials and high-performance lubricants, modern manufacturing processes with additional post-processes as shot peening and superfinishing as well as advanced calculation methods, have allowed an optimized utilization of the allowable pitting and bending stress numbers in recent years. As a result of the increased power density, however, the stresses below the surface rise with the consequence of an increased risk of fatigue failure initiation in the material below the surface. This paper describes main characteristics of a failure mode characterized by tooth breakages which start in the area of the active flank from cracks that are typically initiated at a considerable depth beneath the loaded flank surface. Based on theoretical and experimental investigations, relevant influence parameters related to gear design, operating conditions and material strength on the failure mode “Tooth Flank Breakage” will be discussed and basic principles of a developed calculation model to evaluate the risk of such failures presented. Finally, exemplarily experimental results from gear running tests, which failed due to flank breakage, are compared to the results of the new calculation model.

Effusion Cooled Combustor Liner Tiles With Modern Cooling Concepts: A Comparative Experimental Study

2016 ◽  
Author(s):  
Thomas Jackowski ◽  
Achmed Schulz ◽  
Hans-Jörg Bauer ◽  
Miklós Gerendás ◽  
Thomas Behrendt
Keyword(s):  
Pressure Difference ◽  
Open Loop ◽  
Test Rig ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Cooling Hole ◽  
Manufacturing Techniques ◽  
Aero Engines ◽  
Density Ratios ◽  
Combustor Liner

Advanced combustion techniques in aero engines require highly effective cooling schemes of combustor liners. One parameter affecting the cooling performance is the geometry of the cooling holes themselves. So far, the freedom in the design of cooling holes was limited due to the manufacturing techniques. With emerging additive manufacturing methods, e.g. Direct Metal Laser Sintering, however, the geometry of the cooling holes is virtually unlimited. Especially the entrance and the curvature of the cooling holes determines the through-flow of the hole and consequently the cooling performance of the ejected cooling film. In this study a set of combustor liner tiles with two innovative and four traditional cooling hole geometries will be analyzed and compared to each other in terms of cooling performance. The innovative geometries have bent cooling holes with a nearly horizontal outlet. All specimens have the same cooling hole pattern. The cooling performance is determined by comparing the total cooling effectiveness for a given pressure difference across the combustor liner tiles. The coolant mass flow rate is gained from experimentally determined discharge coefficients for the respective pressure difference. The first set of measurements is conducted in an atmospheric open-loop test rig at reduced temperatures but realistic density ratios between hot gas and coolant. The specimen with the best cooling performance has been selected for an investigation in a high pressure test rig at realistic combustor conditions (pressure, temperature) including fluctuations of the cooling air to simulate combustion instabilities. The cooling performance again is determined by the total cooling effectiveness for a given pressure difference across the combustor liner tiles.

Tribological Performance of PTFE Composites Filled with Spherical-Graphite

2011 ◽  
Vol 197-198 ◽  
pp. 1184-1187
Author(s):  
Jian Wei Sun ◽  
Li Qin Wang ◽  
Le Gu
Keyword(s):  
Friction Coefficient ◽  
Impact Strength ◽  
Wear Rate ◽  
Tribological Performance ◽  
Flake Graphite ◽  
Test Rig ◽  
Ring Configuration ◽  
Spherical Graphite ◽  
Ptfe Composites ◽  
Better Than

The tribologcial performance of PTFE composites filled with different contents of spherical-graphite and Flake-graphite were comparatively evaluated on MM-200 test rig in block-on-ring configuration under dry condition. The microstructures of worn surfaces of PTFE composites were examined with SEM, and wear mechanisms was also analyzed. The changes of notched impact strength with the content changed were also considered. The results show that the tribological performance of spherical-graphite was better than flake-graphite with same weight filled: The friction coefficient of spherical-graphite, about 0.10~0.15, was under flake-graphite, about 0.12~0.18; the wear rate of spherical-graphite was lower than flake-graphite at each content. Notched impact strength of spherical-graphite was from 7.0kJ/m2 to 8.7 kJ/m2 with the content increased, while flake-graphite was fall rapidly from 8.5kJ/m2 to 3.0kJ/m2 with the content added more than 5wt. %.

Characteristics of Fretting Wear in a Press-Fitted Shaft Subjected to Bending Load

2010 ◽  
Vol 97-101 ◽  
pp. 1269-1272 ◽  
Author(s):  
Dong Hyung Lee ◽  
Seok Jin Kwon ◽  
Won Hee You
Keyword(s):  
Fatigue Life ◽  
Wear Rate ◽  
Contact Surface ◽  
Early Stage ◽  
Load Condition ◽  
Surface Profile ◽  
Fretting Wear ◽  
Test Machine ◽  
Wear Coefficient ◽  
Bending Load

This paper presents the results of an experimental investigation of fretting wear characteristics on the contact surface of press-fitted shaft subjected to a cyclic bending load. A series of interrupted fretting wear tests with press-fitted specimens were carried out by using a rotating bending fatigue test machine. The evolution of contact surface profile of press-fitted shaft due to fretting wear were measured with a profilometer. The local wear coefficient during the running-in period is discussed from experimental results and FE analysis. It is found that the maximum depth of fretting wear by repeated slip between shaft and boss occurred at the close of contact edge at the early stage of fatigue life and the regions of worn surface are expanded to the inner side of contact edge as increasing number of fatigue cycles. The initial fretting wear rate at the early stage of fatigue life increased rapidly at all loading condition. After steep increasing, the increase of wear rate is nearly constant in the low bending load condition. The local wear coefficient in running-in period decrease dramatically at the early stage of fretting wear.

Experimental investigation into the effect of chatter on surface micro-topography of gears in grinding

2016 ◽  
Vol 231 (2) ◽  
pp. 294-308 ◽  
Author(s):  
Yao Liu ◽  
Xiufeng Wang ◽  
Jing Lin ◽  
Wei Zhao
Keyword(s):  
Surface Topography ◽  
Functional Performance ◽  
Low Frequency ◽  
Work Piece ◽  
Chatter Vibration ◽  
Multi Scale ◽  
3D Surface Topography ◽  
Tooth Flank ◽  
Flank Surface ◽  
Micro Topography

Chatter affects the surface topography and functional performance of work pieces significantly. The surface topography of work pieces is multi-scale, and the characteristics of different levels of the surface topography are closely connected to the different functional performance of the work piece. The relationship between chatter vibration and surface micro-topography is complicated and not specified. By investigating and understanding this relationship clearly, the manufacturing process can be directed to be controlled more actively and accurately, which helps complete the product with expected surface topography and functional performance. This paper aims to reveal the effect of chatter on the surface micro-topography of gears in grinding. Grinding processes considering different machining states and surface topographies of gears under each process were analyzed comprehensively. The following findings were observed. First, chatter causes significant increase of the tooth flank surface roughness in low frequency and increase of the profile roughness, whereas in a different manner in the different gear flank directions. Second, the influence of chatter mainly concentrates on certain frequency bands of the surface topography, and the effect of chatter on the 3D surface topography is within a frequency range. Third, chatter vibration with its multi-frequency-band characteristics shows a multi-scale influence on the work piece surface topography. The possible mechanisms for the formation of these effects were also discussed.

Sign in / Sign up

Export Citation Format

Share Document