NVH Reduction Lubricants for Transmission Systems

A housing base arrangement for reducing structure-borne sound radiation in drive trains, comprising a support plate with slots that absorb weight forces from the housing and a base plate connected to the support plate for fastening and supporting the base. The slots are designed to dampen audible structure-borne sound in the frequency range of 20 Hz to 20 kHz, while allowing mechanical oscillations to be transmitted to the base. The arrangement enables a cost-effective and low-noise drive train, particularly suitable for industrial wind turbines.

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A grease composition for reducing noise and vibration in sliding members, comprising a copolymer of an aromatic vinyl compound and a conjugated diene compound, a soap-based thickener, and a lubricating oil. The copolymer contains a polymer block derived from an aromatic vinyl compound, such as styrene, and a polymer block derived from a conjugated diene compound, such as butadiene. The copolymer exhibits improved vibration damping properties and thermal stability.

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Purpose The purpose of this study is to investigate the effects of nanoadditive lubricants on the vibration and noise characteristics of helical gears compared with conventional lubricants. The experiment aims to analyze whether nanoadditive lubricants can effectively reduce gear vibration and noise under different speeds and loads. It also analyzes the sensitivity of the vibration reduction to load and speed changes. In addition, it compares the axial and radial vibration reduction effects. The goal is to explore the application of nanolubricants for vibration damping and noise reduction in gear transmissions. The results provide a basis for further research on nanolubricant effects under high-speed conditions. Design/methodology/approach Helical gears of 20CrMnTi were lubricated with conventional oil and nanoadditive oils. An open helical gearbox with spray lubrication was tested under different speeds (200500 rpm) and loads (20100 Nm). Gear noise was measured by a sound level meter. Axial and radial vibrations were detected using an M+P VibRunner system and fast Fourier transfo... Read More

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Electric vehicles (EVs) have gained increased attention in recent years owing to their excellent performance and emission of less hazardous products to the surroundings. The varied design of EVs compared to the internal combustion engine vehicles has created new requirements in lubricants and fluids for their operation. The increasing electrification of vehicle drivetrains has led to lubricants being in contact with more electrical components, such as motors, sensors, battery modules, and power electronics. This has led to different operating conditions, such as being subjected to an electric field, higher rpm, and higher thermal stress, affecting the electrical properties of lubricants, especially for electrified transmission fluid. The electrical properties of lubricants play a vital role in preventing corona discharge and arc absorbance, which can cause premature failure and electromagnetic interference problems in motors, leading to bearing instability, excessive vibrations, and noise. Understanding the interactions of lubricants with the electric field is crucial for optimizing ... Read More

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Transmission mechanism with a lubricating member that contains lubricant and comes into contact with a rotating member while applying a preload based on an elastic force, thereby efficiently lubricating the rotating member with a small amount of lubricant. The lubricating member can be an elastic material or an absorbent member impregnated with lubricant, and can be designed to circulate lubricant, absorb heat, and capture dust particles. The mechanism can be used in applications such as cam mechanisms, gearboxes, and other rotating systems.

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Abstract Vibro-impacts are common in various automotive power transmission applications. They lead to noise issues known as rattling. Input or output toque fluctuations cause gear teeth to separate and commit to complex sequences of drive and coast-side impacts spanning the entire backlash zone. Several recent experimental and theoretical studies characterized the underlying nonlinear structure of the rattling behavior of gear systems, ignoring any influences of lubrication conditions. Those rattle models with no lubricant provisions were shown to compare well with the dry contact measurements. This experimental study aims at complementing these earlier studies providing acoustics and torsional vibration measurements from a single gear pair excited by input torque fluctuations as it operates dry, jet-lubricated and dip-lubricated conditions. A rattle test machine equipped with a lubrication system is presented. Corresponding vibro-impact and sound pressure measurements are provided for a wide range of operating and lubrication conditions. Noise and torsional vibration data under diff... Read More

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The wheel reducer has a compact structure and high transmission power, and is widely used in new energy vehicles. However, it has a narrow space which limits lubrication. This also causes insufficient gear lubrication and poor heat dissipation, which influences the performance and service life of the wheel reducer. Therefore, it is important to find a way for the gear lubrication effectively. In this study, using computer simulation, the influencing factors of gear lubrication of an automobile wheel reducer were explored. The effect of gear speed and the degree of oil immersion on gear lubrication were also analyzed to lubricate the gear efficiently and improve the performance of the wheel reducer.

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<div>Lubrication has been a major area of interest in engineering. Especially in vehicle transmissions, lubrication plays a very crucial role because gears and bearings are constantly subjected to heavy loads. Proper lubrication is essential for maintaining system performance and ensuring endurance life. Insufficient lubrication can lead to excessive wear, increased friction, and eventually, failures in the transmission components. However, excess lubrication can result in power losses due to the resistance offered by the excessive lubricant. Therefore, achieving effective lubrication using optimized lubrication system design is vital for ensuring the longevity and efficiency of the transmission system.</div> <div>Majorly, two types of lubrication methods are used in transmissions: splash lubrication and forced lubrication. This article focuses on forced lubrication, where the lubrication system actively delivers the required flow of lubricant to specific locations within the transmission. Pump outflow, orifice diameters, and channel dimensions are a few of the crit... Read More

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This reprint features 12 research articles that contribute to the research on lubricated bearings. The articles focus on the latest steps in understanding bearing operating behavior, its interaction with lubricants, and its role as a component in the drive train. In addition to the description of novel modeling approaches, a variety of experimental data are presented to provide interesting identification results as well as validation data for the research and engineering community.

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A lubricating oil composition for transmissions, particularly those with wet clutches, that balances fuel efficiency, bearing life, and shift shock prevention. The composition comprises a lubricant base oil blend of mineral and synthetic oils, a calcium sulfonate detergent, a polyalkyl methacrylate polymer, and an amine friction modifier. The base oil blend is formulated to maintain optimal viscosity and film thickness while the additives enhance bearing life, shift performance, and wear protection.

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In recent years, the demand for friction reduction in oil lubrication systems has become increasingly important due to the need to improve fuel economy and achieve carbon neutrality. Ester-based lubricants are known to show low friction and environmentally friendly, and they have high viscosity indexes. In the present paper, first, in situ reflectance spectroscopy was used to clarify the behavior of the oil-film thickness increase during sliding. The results showed that as the number of ester bonds increased from 1 to 4, the ester oil film thickened and the friction coefficient decreased from 0.10 to 0.06. In addition, oleic-acid-type lubricants were found to have superior ability to form a thicker oil film than the isostearic acid type.

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The paper carries out a detailed summary of water-lubricated bearings from five typical aspects: the lubrication regime, the fluid-solid interaction(FSI), the thermal effect, the tribological behaviors and vibration-noise performances. For the lubrication regime, the influencing factors of lubrication regime transition, the judgement criteria and the lubrication mechanism are extracted and acquired. The methodology and the parameters that influencing the temperature rise are summarized. The generation mechanism of tribological behaviors and vibration & noise are obtained. The method of friction reduction, wear decrease, vibration alleviation and noise suppression, the judgement criteria of tribological behaviors and vibration & noise are gained. The paper systematically combs and summarizes the theories and methods of water-lubricated bearings, and points out the existing problems and technologies that need to be solved urgently. The findings can provide a distinct theoretical and methodological reference for further investigation on water-lubricated bearings.

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A lubricating oil composition for reducing noise and vibration in rotating machinery, comprising high phenyl silicone oil, PTFE micropowder, and a polyether-modified silicone oil defoamer. The composition provides improved shock absorption and noise reduction while maintaining low viscosity and convenient refill characteristics.

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Lubricant for ball screw devices and electric power steering systems that exhibits high dynamic viscoelasticity at operating conditions, characterized by a loss tangent (tan δ) of greater than 0.11 at 25°C, 10 rad/s, and 0.01% strain. The lubricant enables improved performance and reliability in ball screw devices and electric power steering systems by maintaining optimal friction and wear characteristics under dynamic loading conditions.

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According to the design requirements of load equalization and vibration reduction for the stern bearing, a water-lubricated stern bearing with self-adaptation capacity is proposed. The bearing is mainly composed of three parts: the bearing bush, the elastic element, and the damping alloy. The elastic element is used to realize static and dynamic load sharing of the stern bearing, reduce the edge effect of the stern bearing, and make the contact pressure evenly distributed in the axial direction, thereby improving the service life of the bearing and reducing the frictional excitation of the bearing. Damping alloy is used to attenuate the shaft vibration transmission from the bearing to the foundation to optimize the vibration transmission characteristics. The revised lubrication models for such bearings are put forward. By analyzing the vibration characteristics of the stern bearing, the results show that the vibration transmission characteristics of the thruster excited to the bearing node are optimized, and the vibration response at the first-order fixed frequency is significantly r... Read More

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A lubricating oil composition for transmissions with improved fatigue life and reduced viscosity, comprising a base oil and an olefin copolymer with a specific molecular weight and hydrodynamic radius range. The composition satisfies a numerical formula relating the olefin copolymer content to the base oil viscosity, and can be produced by blending the base oil and olefin copolymer within specified ranges. The composition is suitable for automatic and continuously variable transmissions, and can be used in a lubricating method that enhances fuel efficiency while maintaining transmission durability.

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A lubricating composition for automatic transmissions that provides improved fuel economy, anti-wear durability, and pump durability while maintaining friction control and anti-shudder performance. The composition comprises an oil of lubricating viscosity, a borated dispersant with sulphur or phosphorus functionality, a calcium-containing detergent, and a combination of phosphorus-containing compounds, along with a linear polymer viscosity modifier and optional additives such as friction modifiers, antioxidants, and corrosion inhibitors.

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This paper proposes a novel double-liner bearing in order to overcome the disadvantages of traditional water-lubricated single-liner bearings. It is expected to achieve a new breakthrough in the performances of high-load, low-resistance, vibration-attenuation and noise-reduction. The fluid-structure interaction dynamic model of sandwich liner bearing is established. Turbulent effect is taken into account. The influences of eccentricity ratios and liner thickness on the lubrication performance are studied. The evolution mechanisms of liner thickness on lubrication performances are revealed. The results show that there are superior lubrication behaviors in sandwich liner bearing. The present study enriches the theoretical systems of the lubrication. It provides new ideas and ways for the design and R&D of the bearing, which is of great significance.

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Lubrication is vital to improve performance, efficiency and durability in transmissions; it serves to minimize wear, noise, vibration and friction. The proper functioning of lubricated transmissions relies on interactions amongst a wide range of physical phenomena (contact dynamics, fluid-structure interaction and heat transfer) operating at different spatial and temporal scales. A lubricated transmission model is proposed in this work to obtain accurate information regarding all physical domains and the coupling thereof to quantify performance, efficiency and durability. The model consists of a thermo-elastically coupled flexible multibody model for the gear pair and a Thermo-Elasto-Hydrodynamic Lubrication (TEHL) model for the lubricant, both based on first principle modelling to ensure high fidelity.

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The article analyzes the vibrations of rolling bearings and their influence on the operation of bearings. An increase in the speed of operation and a boost in power and forces cause an increase in the intensity of vibration fields. The impact of vibrations leads to a change in the characteristics of the contacting surfaces, an increase in friction at the joints and heating of the conjugations. The article describes the factors disturbing vibrations in the joints of machine parts. Ways to reduce vibrations are formulated, including as a result of the use of various lubricants. The analysis of the operability of the rolling bearings of the machine components before and after the use of repair and recovery compounds in lubricants is carried out. The use of repair and restoration compounds based on mineral additives and its addition to the lubricant makes it possible to evaluate the effectiveness of repair and restoration compounds on the processes of friction and wear in rolling bearings. The use of liquid lubricants with mineral additives with a particle dispersion of up to 10 microns ... Read More

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Abstract Noise, vibration, and harshness (NVH) issues pose considerable challenges for electric vehicle powertrain engineers. Gear vibrations generate an intrusive gear whine noise, with significant impact on the sound quality of electric powertrains. Dynamic transmission error (DTE) is the most quantitative indicator for gear NVH. Backlash, time variable meshing stiffness and damping contribute to DTE. Hence, a better understanding of these excitation sources is essential. A gear tribodynamics model is developed using potential energy method to estimate time variable meshing stiffness (TVMS). A fully analytical time-efficient model is proposed for lubricated contact stiffness based on transitions in the regimes of lubrication. The model accounts for the combined effects of surface elasticity and lubricant stiffness. Film thickness and damping coefficients are transiently updated at each instant during meshing cycle. The predictions from this model are compared with measured results from the literature and predicted results from Hertz contact model. The lubricated contact model succe... Read More

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1. Jakubek B, Barczewski R. The influence of kinematic viscosity of a lubricant on broadband rolling bearing vibrations in amplitude terms. Diagnostyka. 2019; 20(1):93102 https://doi.org/10.29354/diag/.... CrossRef Google Scholar

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Lubrication is the sole need of any mechanical system. This makes the mechanical system function as desired with efficiency. A number of lubricants are available to meet these lubrication requirements. As progress is being made, more efficient lubricants are being produced. In this way, nanoparticles in the lubricating oil perform very efficiently and are able to reduce the coefficient of friction (COF) and wear. Several nanoparticles are added to lubricants and evaluated for their performance. There is an improvement in the performance of lubricating oil that has been cited by different researchers. This chapter summarizes the effect of nanoparticles on the performance of lubricating oil. Also provided is a guideline as to what level COF can be reduced, along with the morphological parameters of nanoparticles and base oil.

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With the increasing demand for sustainable technologies, a lot of focus has been directed towards the development of better lubrication methodologies. The widespread use of automobiles has led to environmental degradation, and to deal with this, sustainable lubrication plays a vital role. The current chapter is focused on various basic concepts involved in lubrication for engine and transmission. The various types of lubricants such as synthetic and vegetable oils are included. A section on the basic concepts related to semisolid lubricants has also been added. The categorization has been presented based on the contacting materials such as aluminium, iron, magnesium and copper alloys. Apart from the state of the art in the aforementioned topics, challenges in each type of lubrication have also been discussed.

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During research work, three series of studies were performed to support the importance of using rail lubrication at tramway tracks in Budapest. The first task was to determine the noise reduction efficiency of automated rail lubrication: noise measurements were performed in case of lubricated rails with corrugations, non-lubricated rails with corrugations, grinded rails as well as grinded and lubricated rails. Once the conformity was determined, an additional task was to find the right lubricant. After the noise and braking effect tests of various lubricants, it was a legitimate need to determine the optimum lubricant application because the setting of the devices is based only on the experience of the Operator. Finally, the noise mitigation effect and the friction coefficient affecting the wheel/rail contact with different lubricant application settings were investigated simultaneously. It is important that the lubricant be applied in appropriate amount such that even the safe movement of the trams is guaranteed, but at the same time the noise reduction is satisfactory too. Based on... Read More

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A lubricating oil composition for automatic transmissions that balances performance and durability. The composition comprises a blend of low-viscosity base oils, including Fischer-Tropsch synthetic oils and other low-viscosity oils, and a high-viscosity base oil, typically an olefin copolymer. The blend is formulated to achieve a specific viscosity range, viscosity index, and flashpoint, while maintaining stability and friction characteristics. The composition is particularly suited for use in automatic transmissions, including torque converters, wet clutches, and gear bearing mechanisms.

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A motor housing with built-in damping features to reduce noise and vibration. The housing features axial grooves along its circumference that can be empty or filled with a damping medium, which increases the housing's damping coefficient and reduces rigid connections between components. This design effectively mitigates electromagnetic noise generated by motor vibrations, particularly in applications requiring high NVH performance.

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This paper analyses the vibrations emitted by a set of grease lubricated ball bearings run under load, when lubrication conditions alternate between good and insufficient. Conditions are varied by adjusting the operational parameters rotational speed and temperature. The dependency of the vibration signature on the lubrication ratio is considered. The results show a good correlation between and spectral kurtosis for a given frequency band, a: when the bearing is new, and b: when is below 0.6.

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The rapid growth of electrified vehicles and increased electrical componentry in the powertrain has resulted in a requirement for new, tailored lubricating fluid technologies

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This article aims to research the generation of a vibration and noise by reduction gear to find opoportunities to reduce vibration, calculate noise levels, and develop engineering practices for the calculation of noise levels.

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The influence of changes in the physical properties of lubricants on thermal elastohydrodynamic lubrication solutions is examined numerically at the nominal line contact for both Newtonian and non-Newtonian fluids. Specific heat, thermal conductivity, density, and viscosity were considered as functions of temperature and pressure for polyalphaolefin, polyglycol, and mineral oils. It was found that, when considering the physical and rheological properties of lubricants individually, the solutions were over- or under-estimated. The thermal conductivity formula mostly corresponds to solutions for both fluids. The effects of changes in the physical properties of non-Newtonian lubricants were shown to be less than those of Newtonian lubricants. Near-identical qualitative behaviors occurred regardless of oil type under these lubricant models.

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A lubricating oil composition for push-belt continuously variable transmissions that improves fuel efficiency while maintaining anti-seizure, anti-wear, and anti-fatigue performance. The composition comprises a lubricant base oil with a specific viscosity profile, a poly(meth)acrylate viscosity index improver, a boron-containing succinimide compound, a borate ester compound, and a calcium detergent. The composition also includes a phosphorus-containing anti-wear agent and an ashless friction modifier to enhance friction coefficients and torque transmission capacity.

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A transmission lubricating oil composition that enhances high temperature stability and shear stability while maintaining low temperature fluidity over long-term use. The composition comprises a base oil with a kinematic viscosity of 1.5-3.2 mm^2/s at 100°C, a poly(meth)acrylate viscosity index improver in the range of 0.001-0.2% by mass, and a NOACK evaporation loss of 10% or less. The product of the NOACK evaporation loss and Brookfield viscosity at -40°C is 10,000 mPa·s or less.

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Lubricating compositions for driveline applications, such as transmissions, gearboxes, and axles, that provide enhanced antiwear and extreme pressure performance while meeting stringent sulfur and phosphorus content requirements. The compositions comprise a base oil and a specific additive package that includes a novel monohydrocarbyl-substituted dimercaptothiadiazole derivative, which provides improved gear scuffing resistance and load-carrying capacity. The additive package also includes conventional components such as dispersants, detergents, and friction modifiers, and the overall composition has a sulfur content of less than 2,500 ppm.

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A centrifugal pendulum assembly for damping rotational irregularities in a vehicle engine drive shaft, comprising a centrifugal force spring coupled to the drive shaft to generate a restoring torque counter to rotational nonuniformity, and a lubricating medium that at least partially wets the centrifugal pendulum to dampen impact noises. The lubricating medium is contained within a housing that prevents migration and maintains a predefined level during operation, and the housing serves as a burst protection for the centrifugal pendulum.

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A lubricating oil composition for automatic transmissions comprising 55-85% Fischer-Tropsch synthetic oil (2-4 mm2/s at 100°C), 1-10% olefin copolymer (150-1000 mm2/s at 100°C), and a polymethacrylate (10,000-50,000 Mw) to achieve a viscosity index of at least 190, a Brookfield viscosity of ≤6000 mPa·s at -40°C, a 100°C kinematic viscosity of 6-7 mm2/s, and a KRL shear stability of ≤3% reduction.

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Lubricant composition for gearboxes and differentials that reduces friction vibrations and noise. The composition comprises a base oil and a specific diamine monosodium salt, such as N-(oleylalkyl)-1,3-propanediamine oleate, which is added in a concentration of 0.3-0.5 wt%. The lubricant composition is particularly effective in reducing stick-slip phenomena in differential gears, thereby improving ride comfort.

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The lubricant properties have a significant influence on the static and dynamic performance characteristics of journal bearing such as load-carrying capability, minimum fluid film thickness, maximum pressure, lubricant flow rate, damping coefficients, stiffness coefficients, etc. The present document reviews the behaviour of various lubricants such as power-law lubricants, couple stress lubricants, micropolar lubricants, ionic liquid lubricants and space lubricants. The influence of these lubricants on the performance of hydrostatic, hydrodynamic and hybrid journal bearings is discussed. An effort is made to develop the understanding to choose the suitable lubricant for journal bearings for different journal bearing configurations. Journal bearings operated with non-Newtonian lubricants have shown better performance compared to Newtonian lubricants. Ionic liquid lubricants have shown high potential in vacuum applications and extreme temperature environment such as in bearings of spacecraft moving mechanical assemblies.

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This chapter aims to provide a general overview of modern transmission lubricants; how they are specifically tailored to the variety of transmissions in the marketplace, and how they are expected to evolve to meet future transmission requirements. It provides a basic description of the different chemical constituents used to create a lubricant. The chapter discusses a basic overview of transmission hardware. Transmission lubricants, which enable the transfer of power from the engine to the vehicle's wheels via a combination of gears, hydraulics, and clutch friction typically have a performance additive treat rate of 5 to 15% and 2 to 20% viscosity modifiers. Basestocks used to formulate transmission fluids are normally mineral and/or synthetic oils. The low-temperature viscometric requirements for the transmission will influence the type of basestock used. Various elastomeric materials such as nitrile, silicone, polyacrylate rubbers, and fluoroelastomers are used in transmission seals that prevent both internal and external leakage of fluid.

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Gear oils are the unseen workhorses of the automotive lubricants. Lacking the advertising clout and consumer attention that engine oils command, they are the lubricants for the remainder of the automotive power train. The equipment utilizing automotive gear lubricants include manual transmissions, drive axles, power take-offs, and nondrive applications. Other automotive applications using gear lubricants are front steer axles in rear-drive vehicles, trailer axles being pulled or articulated with the drive tractor, power take-off assemblies for transferring engine power to drive auxiliary equipment, and the rear bearing axle assemblies on front-wheel-drive vehicles. The first defining category for the design and formulation of an automotive gear lubricant is the viscosity. The American Petroleum Institute designates service categories for automotive gear oils based on the level of antiwear or Extreme Pressure protection required. Similar to the compatibility properties, synthetic gear lubricants are fully miscible with petroleum-based gear lubes.

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Lubricants are an important part of any tribological system [...]

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The serviceability and durability of mechanisms substantially depends on a correctness of the choice of lubricants and a way of greasing. As lubricants for gears of reducers and their bearings use liquid hydrocarbon and synthetic oils and also ductile lubricants. Influence of lubricant on a vibration activity of mechanisms is considered. The criterion of quality determined the minimum power of a vibration signal here. As a measuring device the analyzer of vibration Vibro Vision-2 is used. At the beginning of article the studied object a four-stage reducer is described. Further results of measurements of power of a vibration signal in the given frequency range for each of the considered lubricants are shown. At the same time the frequency range is divided into strips. The root-mean-square value (RMS) of vibration speed which determines vibration signal power was measured in each strip. RMS observed data in each frequency band is presented as a tables and schedules. Further on the basis of the obtained data the histogram of distribution of RMS on frequency stripes where each of the c... Read More

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The rapid growth of electrified vehicles and increased electrical componentry in the powertrain has resulted in a requirement for new, tailored lubricating fluid technologies

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Abstract In this paper, an elastohydrodynamic impact model is proposed, and the prediction of lubricating film performance considering squeeze effect and thermal effect is presented. Effects of sinusoidal impulse load, sinusoidal impulse entrainment velocity, multifrequency vibration, and acoustic noise on thermomechanical characteristics of gear lube are numerically investigated. Results show that both sinusoidal impulse load and sinusoidal impulse entrainment velocity can cause remarkable increases in central film thickness and minimum film thickness and induce small reduction in friction coefficient. The sinusoidal impulse load causes considerable increase in central film pressure; however, the sinusoidal impulse entrainment velocity induces significant decrease in central film pressure. The multiple high constant frequency vibration causes considerable increment in film pressure, but maintains small fluctuation in film thickness. Additionally, the consequence of multiple high constant frequency vibration induces evident reduction in friction coefficient.

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The article deals with the basics of technology for improving the performance of friction units of machines and their diagnostics by acoustic emission method. It is shown that it is important to create a lubricant film on the friction surfaces before they are mechanically loaded, which ensures "soft" starting conditions during their start-up. After the creation of the lubricant film, the friction unit is mechanically loaded with the regulation of friction heat generation, which, together with the filtration of the lubricant and timely cleaning of the filter elements from pollutants, lengthens the life of the lubricant film and increases the service life of the friction unit.

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A grease composition for reducing low-frequency noise in sliding components, comprising a polyalphaolefin (PAO) base oil, lithium soap thickener, and a combination of two styrene-based block copolymers with different glass transition temperatures (Tg), one below -20°C and the other at -20°C or higher. The composition is applied to sliding surfaces of rotating components, such as motor shafts and gears, to reduce noise in the 100-500 Hz frequency range.

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