Industrial Gear Research Articles

The Effect of a Gear Oil on Abrasion, Scuffing, and Pitting of the DLC-Coated 18CrNiMo7-6 Steel

The transmissions of mining conveyors are exposed to very harsh conditions. These are primarily related to the contamination of the gear oil with hard particles coming from coal and lignite, which can cause intensive abrasive wear, scuffing, and even pitting, limiting the life of gears. One of the ways to prevent this problem is the deposition of a wear-resistant coating onto gear teeth. However, a proper choice of gear oil is an important issue. The abrasion, scuffing, and pitting tests were performed using simple, model specimens. A pin and vee block tester was employed for research on abrasion and scuffing. To test pitting, a modified four-ball pitting tester was used, where the top ball was replaced with a cone. The test pins, vee blocks, and cones were made of 18CrNiMo7-6 case-hardened steel. A new W-DLC/CrN coating was tested. It was deposited on the vee blocks and cones. For lubrication, three commercial industrial gear oils were used: A mineral oil, and two synthetic ones with polyalphaolefin (PAO) or polyalkylene glycol (PAG) bases. The results show that, to minimize the tendency forabrasion, scuffing, and pitting, the (W-DLC/CrN)-8CrNiMo7-6 tribosystems should be lubricated by the PAO gear oil.

Mechanism for improvement of friction/wear by using Al2O3 and SiO2/Gear oil nanolubricants

Gear oil of heavy mining machineries are designed to provide anti-wear and anti-friction protection under extreme load condition. In present study thermophysical and tribological properties of industrial gear oil with nanoparticles additives (Al2O3 and SiO2) has been experimentally evaluated. Morphology of dry nanoparticles under FE-SEM shows that both nanoparticles are spherical. DLS test shows the presence of mild-agglomeration of nanoparticles in the dispersion. Density and viscosity of nanolubricants is tested with varying temperature and particle volume fraction. Measured viscosity results for Al2O3/gear oil nanolubricants follow the existing empirical model and new model has been proposed for SiO2/gear oil nanolubricants. Anti-friction and anti-wear properties of nanolubricants are tested on pin-on-disc test apparatus. FE-SEM and energy dispersive spectroscopy (EDS) analysis of wear scar (pin SS-304), evident the occurrence of ball bearing and surface polishing effects, which may be responsible for advanced tribological properties of the oil. Test results reveals that ball bearing have dominating effect in enhancement of tribological performance.

Adipates of poly(propylene oxide-co-tetrahydrofuran) as a novel base stock for varied lube applications

Three biodegradable polyalkylene glycols containing 1:1, 1:2 and 1:4 mol% fraction of propylene oxide and tetrahydrofuran were synthesized and denoted as 1,1-PTH, 1,2-PTH and 1,4-PTH. The synthesized polyalkylene glycols were subsequently treated with adipic acid to get desired esters. At first, three different copolymers of propylene oxide and tetrahydrofuran, namely 1,1-PTH, 1,2-PTH and 1,4-PTH (polyglycol containing 1:1, 1:2 and 1:4 mol% fraction of PO and THF), with molecular weights 564.0, 838.6 and 1070.7 were synthesized. Then, the esterification of the synthesized polyglycols was carried out using p-toluenesulfonic acid as the catalyst and toluene as a solvent. The obtained esters 1,1-PTHAD, 1,2-PTHAD and 1,4-PTHAD were observed to have the molecular weights 1292.1, 1705.0 and 2201.1, respectively. After molecular and physicochemical characterizations, the tribological properties were also evaluated. A comparison of the properties of these esters was made, and it was found that 1,1-PTHAD, 1,2-PTHAD and 1,4-PTHAD are favorably used as metalworking fluid, industrial gear oil and compressor lubricant base oil, respectively.

Comparison of Accuracy in Cutting Dental Profiles Between Differential Methods Approach Upward with a Lower Approach to Making Straight Gear Wheels

In the world of industrial gear use, it cannot be denied, every machine in the industrial world uses a component, namely gears to move rotating power. For this reason, in making gears the precision of the gear profile must be considered. The purpose of this study is to compare the accuracy of cutting the dental profile between the approach differential method and the approach to the bottom. This research is an experimental research. Based on the results of data analysis on the comparison of the precision of cutting dental profiles between the approach differential methods and the approach to the bottom, the upward approach is more appropriate in terms of thickness and number of teeth. The number of samples used in the study of 12 gears consisting of 6 gears was carried out with the approach differential approach method, and 6 gears were carried out by the differential approach approach method. Each sample is measured in thickness and the number of teeth in a straight gear. After measurement, the data is processed using the t-test formula to see the significant difference in the accuracy of the dental profile. Based on the results of the t-test analysis that has been carried out there are differences in the gears produced. The approach to differential approach to getting better gear results.

The Possibility of Modifying the Lubricity of Transmission Oils in Industrial Gears

The Possibility of Modifying the Lubricity of Transmission Oils in Industrial Gears

Modular hybrid models to simulate the static and dynamic behaviour of high-speed thin-rimmed gears

Several modular hybrid gear dynamic models are presented which account for both the local phenomena associated with the instant contact conditions between the tooth flanks and the more global aspects related to shafts, bearings and particularly the contributions of light thin-rimmed/-webbed gear bodies. The proposed models combine sub-structures, lumped parameter and beam elements to simulate components with linear behaviour such as webs, rims, shafts, etc. while local mesh elasticity is simulated by time-varying, possibly non-linear Winkler foundations. A specific interface has been developed to connect discretised tooth contact lines with continuous finite element models and avoid singularities in tooth load distributions. A number of comparisons with numerical and experimental results show that the proposed modelling is sound and can capture most of the quasi-static and dynamic behaviour of single stage reduction units with thin-webbed gears and/or pinions. Finally, the modelling strategy is applied to the analysis of high–speed industrial gears and results are presented which illustrate the interest of the proposed methodology compared with the classic gear dynamic models.

Reconstructing global marine fishing gear use: Catches and landed values by gear type and sector

The interaction between fishing gears and the marine environment define ‘fisheries,’ and the effect of gears on marine ecosystems and fish stocks has been the source of much debate. Here, we present the first summary of globally reconstructed fisheries catches by major gear categories for 1950–2014. We used the Sea Around Us reconstructed global catch database that accounts for reported and unreported fisheries catches, and associated all catches to a fishing gear category. We assigned all industrial (i.e., large-scale) fisheries catches to industrial gear categories by fishing country, taxon, year and the area of fishing. Additionally, we derived catches by individual small-scale gear types for the most-important small-scale fishing countries in each of nine regions around the world, and applied their gear use to similar countries in each of the regions, to serve as a preliminary small-scale catch-by-gear assignment that can be improved upon over time. The combination of these account for gear use for all marine fisheries globally. We found that two industrial gear types, bottom trawling and purse seining, jointly account for over 53% of all catches, while bottom trawling alone dominated discarded catches. In the small-scale sector, over 60% of catches were caught by gillnets, various line gear, and encircling nets. Small-scale fisheries contributed most to the value of landed catches, while industrial bottom trawlers were responsible for discarding large amounts of potentially valuable catches. Catches by purse seines fluctuated over time, mainly due to variability of the underlying species, e.g., anchovies and sardines. The distribution and scale of use of different fishing gears, combined with knowledge of their divergent environmental impacts should allow a new wave of research into the global impacts of fisheries.

Industrial Gear Oils: Tribological Performance and Subsurface Changes

This study examined the tribological performance of three gear oils (Oils A, B and C), in relation to surface and microstructural changes. Oil A contains molybdenum dithiophosphate friction modifier, Oil B contains amine molybdate combined with zinc dialkyl dithiophosphate antiwear additive, while Oil C contains phosphonate and a commercial gear oil package. Following sliding tests of a hardened AISI 52100 steel ball on a spheroidized AISI 52100 steel disc, the worn surfaces were chemically studied using Raman and energy-dispersive X-ray spectroscopy. The tribological performance for each oil was different, likewise the nature of the tribofilm formed. After a 5 min sliding test, the hardness-depth profile of the worn surfaces was measured; also the cross-sectional microstructure was examined using scanning electron microscopy combined with focused ion beam preparation and transmission electron backscattered diffraction (t-EBSD) techniques. With Oil A, there was a relatively small increase in surface hardness (33% greater than that of the unworn surface), whereas with Oils B and C, the average hardness near the surface was 100% greater than that of the unworn surface. The cross-sectional microstructure using Oil A also differed from Oils B and C, which were quite similar. The result shows that with Oil A refinement of the ferrite grains spreads deeper into the material (> 10 µm), whilst with Oils B and C it was largely limited to 2–3 µm below the surface. It is concluded that the lubricant formulations and their associated tribofilms influenced the extent of deformation in the subsurface layers and consequently influenced the wear performance.

Optimization of Recycled Glass Fibre-Reinforced Plastics Gear via Integration of the Taguchi Method and Grey Relational Analysis

The increase in demand for industrial gears has resulted in the increase in usage of plastic-matrix composites particularly glass fibre-reinforced plastics as the gear materials. The usage of these synthetic fibers is to enhance the mechanical strength and the thermal resistance of the plastic gears. Nevertheless, the production of large quantities of these synthetic fibre-reinforced composites poses a serious threat to the ecosystem. Comprehending to this fact, the present work aimed at investigating the effects of incorporating recycled glass fibre-reinforced plastics in various compositions particularly on dimensional stability and mechanical properties of gear produced with diverse injection moulding processing parameters setting. The integration of Grey relational analysis (GRA) and Taguchi method was adopted to evaluate the influence of recycled glass fibre-reinforced plastics and variation in processing parameters on gear quality. From the experimental results, the blending ratio was found as the most influential parameter of 56.0% contribution in both improving tensile properties as well as in minimizing shrinkage, followed by mould temperature of 24.1% contribution and cooling time of 10.6% contribution. The results obtained from the aforementioned work are expected to contribute to accessing the feasibility of using recycled glass fibre-reinforced plastics especially for gear application.

Improved SPH simulation of spilled oil contained by flexible floating boom under wave–current coupling condition

A multi-phase Smoothed Particle Hydrodynamics (SPH) method is developed to model the failure process of a flexible oil boom. An algorithm is proposed based on the dynamic boundary particles (DBPs) for preventing particle disorders of multi-phase fluid particle movement around solid boundary. The improved multi-phase SPH model is firstly validated by the experimental data of a wedge falling into a two-layer oil–water fluid. Then a numerical wave–current flume is established with a piston-type active absorbing wave generator and a circulating current system. The model reliability is validated against the measured vertical profiles of velocity. Simulation of the flexible floating boom movement is implemented by introducing a Rigid Module and Flexible Connector (RMFC) multi-body system. The model is finally applied to the simulation of movement of a flexible floating boom in containing industrial gear oil under the action of combined waves and currents. Good agreements are obtained between the SPH modeling results and the experimental data in terms of the ambient wave–current field, hydrodynamic responses of the floating body and evolution process of the oil slick for the flexible boom. The hydrodynamic responses and containment performances of the flexible floating boom are also compared with those of the rigid one. It is found from both the experimental and numerical results that two vortices of the water phase exist in the front and rear of the boom skirt and the size of the front vortex decreases with increase of the current velocity while the wake vortex is reversed. It is also found that the skirt of the flexible boom has a larger magnitude of swaying and rolling than the rigid one and the maximum quantity of escaped oil of a flexible boom within one wave cycle is about 5% more than a rigid one under the present test conditions.

Evaluation on the feasibility of using bamboo fillers in plastic gear manufacturing via the Taguchi optimization method

An increase in demand for industrial gears has instigated the escalating uses of plastic-matrix composites, particularly carbon or glass fibre reinforced plastics as gear material to enhance the properties and limitation in plastic gears. However, the production of large quantity of these synthetic fibres reinforced composites has posed serious threat to ecosystem. Therefore, this work is conducted to study the applicability and practical ability of using bamboo fillers particularly in plastic gear manufacturing as opposed to synthetic fibres via the Taguchi optimization method. The results showed that no failure mechanism such as gear tooth root cracking and severe tooth wear were observed in gear tested made of 5-30 wt% of bamboo fillers in comparing with the unfilled PP gear. These results indicated that bamboo can be practically and economically used as an alternative filler in plastic material reinforcement as well as in minimizing the cost of raw material in general.

Premature Failure of an Industrial Mixer Timing Gears

A systematic and practical methodology was adopted to determine the root cause(s) of the premature failure of a pelletizer mixer timing gear. The investigation activities covered all possible causes of failure and included field examination, interview of engineers and operators, lubrication analysis, metallurgical examination. Fracture surfaces and microstructure of gear material were examined, and hardness profiles were developed. Analyses of shaft misalignment and teeth profiles were performed and found to be within acceptable limits. Results clearly indicate the surface hardness deficiencies in many locations specifically at center of the driven gear, area of severe pitting. The developed hardness profile for all locations is lower than that specified by the manufacturer. Fractographic analysis revealed that failure occurred by pitting followed by crack propagation. A number of cracks are seen to branch in different directions indicating the presence of high contact stresses combined with weak surface strength. Bending fatigue and pitting fatigue stress calculations revealed that the safety factor under contact is well below the desired value.

Direct acetylation of sunflower oil in the presence of boron trioxide catalyst and the adduct usage as the base stock and lubricant additive

Lubrication properties of sunflower oil have been modified by epoxidation in the first step and acetylation of the obtained epoxide in the second step. Epoxidation has been followed in dichloromethane solution in the presence of hydrogen peroxide and acetic acid as oxidizing agent and sulfuric acid as catalyst. The reaction has been monitored and optimized by measurement of iodine value, epoxy content, and recording the FTIR spectrum at different experimental conditions. Acetylation has been performed by enduring the optimized conditions of epoxidation reaction, in the presence of boron trioxide as catalyst and at elevated temperature. The recent reaction has been monitored and optimized by measurement of hydroxyl value, epoxy content, and recording the FTIR spectrum at different experimental conditions. The final product of both,epoxidation and acetylation reactions has been confirmed by FTIR and NMR data. Relative to sunflower oil, pour point and oxidation stability of the modified oil has considerably been improved. The modified oil has successfully been employed in the formulation of industrial gear oil. The investigation on the possibility of the additive application of the modified oil, as well as its miscibility with additives was considered. KEY WORDS : Sunflower oil, Lubrication, Epoxidation, Acetylation, Borontrioxide, Gear oil blending, Polyalphaolephin-100, Polyisobutene Bull. Chem. Soc. Ethiop. 2017 , 31(1), 39-49. DOI: http://dx.doi.org/10.4314/bcse.v31i1.4

Thermal and Rheological Properties of Industrial Mineral Gear Oil and Paraffinic Oil/CNTs Nanolubricants

Carbon nanotubes (CNTs) are used as a nanoadditive due to their unique properties and for improving the lubricant’s properties. In this research, the effect of CNTs in different concentrations (0.1, 0.5, 1 and 2 wt%) on kinematic viscosity, pour point, flash point and thermal conductivity coefficient as four quality parameters which are effective in the functionality of oil is evaluated and compared against the standard Mobil gear 627 and paraffinic mineral oils. The samples were tested according to ASTM D-445, ASTM D-97 and ASTM D-92 standards, respectively. The results indicated that the thermal conductivity, flash point, pour point and kinematic viscosity of nanolubricants with low concentration of CNTs improved with respect to the base oil. Dispersion of CNTs as additive has improved the lubricant properties and operational characteristics of Mobil gear 627 and paraffinic mineral oils.

Investigation on Wear Behavior of Bamboo Filler Reinforcement of Injection Moulded Plastic Gear

An increase in demand for industrial gears has instigated the escalating uses of plastic-matrix composite, particularly carbon or glass fibre reinforced plastics as gear materials to enhance the mechanical strength and thermal resistance of plastic gear. Nevertheless, the production of large quantity of these synthetic fibres reinforced composites has posed serious threat to ecosystem. This study is conducted to study the applicability and practical ability of using bamboo fillers particularly in plastic gear manufacturing as opposed to synthetic fibres. The Taguchi method is used to investigate the effects of gear test rig parameters and bambo filler reinforcement on wear behaviour of injection moulded plastic gear. The results revealed that the use of natural fillers such as bamboo in the plastic gear industry is practical and economically viable.

Viscosity Index Improver for Engine Oils: An Experimental Study

Engine oils are widely used for lubrication purposes in automobile and related industries. Viscosity Index (VI) improver has found its largest commercial applications as additives to engine oils. Examples are power steering fluid, aircraft piston engine oils, modern internal-combustion engines, turbine engine oils (stationary and aircraft), and industrial gear oils. Viscosity Index improvers are added in the lube oils to reach the desired Viscosity Index (VI). The enhancement of VI of lube oils (Servoneum 100, Servopress 68, Servomesh SP 220, and Servocut 335) by the addition of viscosity index improvers (Methylmethacrylate (MMA), Polybutadiene rubber (PBR), and Polyisoprene-cis) has been studied. VI of blended oils, made from the lube oils (Servoneum 100, Servopress 68, Servomesh SP 220, and Servocut 335) by the addition of MMA, PBR, and Polyisoprene-cis, has shown the potential to reach the maximum value. It has been found that the occurrence of maximum VI depends on the lube oil used and the type and concentration of viscosity index improver.

LMR-Based Optical Fiber Refractometers for Oil Degradation Sensing Applications in Synthetic Lubricant Oils

In this work, is presented the fabrication and characterization of optical fiber refractometer based on the lossy mode resonances (LMR). Indium-tin-oxide and tin dioxide thin films deposited on optical fibers are used as the LMR supporting coatings. These resonances shift to the red as a function of the external refractive index. The refractometer has been used to characterize the degradation of a synthetic industrial gear lubricant oil at working temperature.

Fault diagnosis of industrial robot gears based on discrete wavelet transform and artificial neural network

Fault diagnosis of industrial robot gears based on discrete wavelet transform and artificial neural network

Dry Broaching Using Carbon Free Steel as Tool Material

One major application of broaching is the production of internal gears for the automotive industry. Today, broaching with tools made of high speed steel is state of the art. However, because of the low hot hardness the cutting parameters are limited and process lubrication is mandatory. A promising alternative is the use of the carbon free cutting material MC 90 Intermet, which possesses a higher hot hardness and increased thermal conductivity compared to HSS. These properties offer dry broaching of gears with modules higher than mn = 1.5 mm. In this paper, the influence of different coatings and cutting parameters on the tool wear, cutting forces and tool temperatures are investigated.

Methods of Efficient Parameters Multifactorial Determination of Industrial Manipulators Gears and Electric Drives

The method of multifactorial determination of efficient parameters of springy gears and electric drives of load vertical traverse by the balanced manipulators is developed. The complex approach is offered in relation to the power circuit choice of the electromechanical force compensating systems taking into account minimization of mass, applicability of a nonreversible motor and work with low value of the maximum torques, active limitation of dynamic efforts in springy elements of mechanics using electric drive and other factors allowing to improve the design of electromechanical systems of special lifting devices, industrial manipulators and robots, simulator complexes and testing workbenches. The choice of the desired reduction radius value of the gear from the allowable value range is recommended to be made using two approaches: an optimum setting using minimization criterion of the total maximum motor torque and a compromise derivative of the efficient value of the reduction radius satisfying performance of all the considered conditions.