Gear lubrication pdf

Lubrication of Gears

Introduction This review of elastohydrodynamic lubrication EHL was derived from many excellent sources Refs. An excellent general reference on all aspects of tribology is the Encyclopedia of Tribology Ref. Gear teeth, rolling element bearings, cams, and other non-conforming Hertzian contacts are lubricated by the EHL mechanism. Figure 1 is an enlarged view of a lubricated Hertzian contact. It shows the distribution of film pressure and film thickness between two steel cylinders in rolling contact.

Note that Figure 1 exaggerates the vertical distance and shrinks the horizontal distance for purposes of illustration. An actual EHL contact is typically 1, times wider than the film thickness.

The EHL contact starts with a slowly converging inlet region where the lubricant is entrained and hydrodynamic pressure is generated. The film pressure gradually increases in the inlet region until it reaches the leading edge of the Hertzian region where the pressure quickly builds to values that are essentially equal to the Hertzian contact stress. Under high pressure, the lubricant viscosity increases exponentially to the extent that the lubricant cannot escape because its viscosity is too high.

Within the Hertzian region, the bodies are separated by a constant film thickness. At the end of the Hertzian region there is a constriction near the outlet that forms the minimum film thickness. Within the Hertzian region the film pressure follows the Hertzian pressure, except for a sharp spike in pressure just upstream from the constriction at the outlet.

Within the constriction, the film pressure drops rapidly to atmospheric pressure. The inlet region. The lubricant that is adsorbed on the surfaces of the contacting bodies is entrained into the EHL contact by the rolling motion of the bodies. Entrainment of the lubricant is greatly facilitated by its viscosity increase because the high viscosity resists flow, makes it more difficult to squeeze the lubricant out, and viscous drag forces cause it to move with the surfaces into the Hertzian region.

As a result, the inlet pumps the film up to a thickness that is sufficient to separate the opposing bodies. EHL film thickness is determined by the viscosity and pressure-viscosity coefficient of the lubricant in the inlet region. For gears, the lubricant that is entrained into the inlet is molecularly attached to the surfaces of the pinion and wheel teeth and consists of thin boundary layers that immediately take on the bulk surface temperatures of the pinion and wheel teeth.

Consequently, EHL film thickness is determined by the equilibrium bulk surface temperatures of the pinion and wheel teeth in the inlet region before the lubricant reaches the Hertzian region. Bulk surface temperature. When the pinion and wheel are running under a given load, the surfaces of the pinion and wheel teeth are heated by the sliding friction between the gear teeth and gradually increase in temperature until finally reaching the equilibrium bulk surface temperatures after many revolutions.

Inlet shear heating. In a fully flooded EHL contact, only a fraction of the lubricant can pass through the contact.

gear lubrication pdf

Therefore, some of the lubricant is rejected and reverse flow occurs in the inlet.Our expert team provides the best advice and products when it comes to high-quality oils and greases, contamination and lubrication storage systems along with lubrication transfer systems. We also provide our customers with further support through training, consulting, equipment servicing and equipment hire to keep their operations running smoothly.

Clean, organised lube rooms with proper storage, colour-coding and identification prevent contamination and enhance safety. The use of Lubrication Engineers enhanced lubricants far significantly reducing downtime and maintenance costs, LE lubricants are also cost-effective, returning the initial price of the lubricant many times over. Equipment that enables effective lubrication in the right quantity, at the right time and at the right point.

Empower staff to be proactive in lubrication management, increase productivity while reducing maintenance costs.

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Last Name. Trusted By. Brands We Trust.Lubrication is essentially required in motor vehicle maintenance. Lubrication must be done properly and the right type of lubrication should be used.

In these types of the lubrication systemit is commonly used in the two-stroke petrol engines such as scooters and motorcycles. It is the simplest form of the lubricating system.

For lubrication purpose, it does not have any separate part like an oil pump. But the lubricating oil is added to the petrol itself during filling in the petrol tank of the vehicle in a specified ratio. When fuel enters the crank chamber during engine operation, oil particles go down into the bearing surfaces and lubricate them.

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The piston rings, cylinder walls, piston pins, etc. If the engine is allowed to remain unused for a considerable time, the lubricating oil separates off from petrol and starts to clogging of passages in the carburettoroccurring in engine start problems. Thus is the main disadvantages of this system. In these types of lubrication systemthe lubricating oil accumulates in an oil trough or sump. A scoop or dipper is made in the lowest part of the connecting rod.

When the engine runs, the dipper dips in the oil once in every revolution of the crankshaft and cause the oil to splash on the cylinder walls. This action affects engine walls, piston rings, crankshaft bearings, and large end bearings. Splash system mostly works in connection with the pressure system in an engine, some parts being lubricated by splash system and the other by a pressure system.

In these types of lubrication systemengine parts are lubricated under pressure feed. The oil from the main gallery goes to the main bearings, after lubricating the main bearing, some of it goes back to the sump, some is splattered to lubricate the cylinder walls and the rest goes from a hole into the crank pin. From the crankpin, it goes through a hole in the connecting rod web to the piston pin, where it lubricates the piston rings.

To lubricate the timing gears and camshaft, the oil is led through a separate oil line from the oil gallery. The valve tape is lubricated by attaching the main oil gallery to the tappet guide surfaces through drilled holes.

An oil pressure gauge on the instrument panel shows the oil pressure in the system. The oil filters and strainers in the system clear off the oil from dust, metal particles and other dangerous particles. It is the combination of a splash system and pressure system of the lubrication system. Some parts are lubricated by splash system and some parts by a pressure system.

Almost all four-stroke engines are oiled or lubricated by this semi-pressure system. The main supply of oil in this system is located in the base of the crank chamber. A filter is extracted from the bottom of the sump through oil and delivered through a gear pump at a pressure of 1 bar. Larger bearing ends are lubricated through a nozzle spray. Consequently, the oil also oils or lubricates crankshaft bearings, cams, cylinder walls and timing gears.

The oil supply is measured with the help of oil pressure gauges. This system is less costly to install. This enables high bearing loads and engine speed to be applied than the splash system. The system in which lubricating of oil collects in the oil sump is known as a wet sump system as a pressure system. But the system in which the lubricating oil is not located in the oil sump is known as the dry pump system. In this system, the vanes sweep the oil from the inlet to the outlet side.

As the drum is applied in an eccentric manner, the volume between the drum and the casting continuously decreases and the oil pressure at the outlet increases. In this system, oil is transported to various engine parts with a sump strainer.

After lubrication, the oil is carried back to the oil sump. In this case, the oil is present in the sump. Therefore, it is called a wet sump lubrication system.SKF uses cookies on our web site to align the information shown as closely as possible to the visitors' preferences and to tailor our web site user experience in general.

See information about Cookies. The basic grease selection chart provides you with quick suggestions on the most commonly used greases in typical applications.

The chart includes the main selection parameters, such as temperature, speed and load, as well as additional performance information. LubeSelect for SKF Greases provides you a user friendly online tool to select the right grease and suggest lubrication frequency and quantity, while taking the particular conditions of your application into account. General guidelines for typical greases for different applications are also available. Cookies information SKF uses cookies on our web site to align the information shown as closely as possible to the visitors' preferences and to tailor our web site user experience in general.

Location Login. Back to top. Home Products Lubrication management Lubricants Lubricant selection. Lubricant selection. Selecting a grease can be a delicate process. SKF has developed several tools in order to facilitate the selection of the most suitable lubricant.

The wide range of tools available includes those from easy-to-use application driven tables to advanced software allowing for grease selection based upon detailed working conditions. Basic grease selection The basic grease selection chart provides you with quick suggestions on the most commonly used greases in typical applications. LubeSelect for SKF Greases LubeSelect for SKF Greases provides you a user friendly online tool to select the right grease and suggest lubrication frequency and quantity, while taking the particular conditions of your application into account.

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Grease selection chart They are open gear systems driven by one or two pinions. They are generally used in the material conversion industries, as well as in the mining industry, steelmaking, cement works, fertilizer plants, waste incineration and composting plants, etc. They are used on various types of machines converting large quantities of materials: tubular mills ball, bar or free fall millscooling, washing and drying drums, rotary ovens and incinerators. Lafarge Group photo This system, which has demonstrated its efficiency on numerous occasions, sprays the lubricant directly onto the gear teeth.

This lubrication system includes a pneumatic pump fitted on the user's drum of lubricant. The pump supplies distribution units positioned above the gears to be lubricated. The progressive distributors fitted on these units direct the lubricant towards the sprayers.

It includes a control cabinet with an air regulation unit, a pneumatic pump on drum and a spraying unit with five nozzles for The drum of lubricant is also fitted with a heating belt to keep the lubricant at optimum temperature.

The pipes can also be fitted with The following hydropneumatic diagram shows the operating principle of this installation. Function principle. The transition to service lubrication must be carried out progressively after the running-in lubrication. The aim is to use as little lubricant as possible to guarantee correct operation of the gear drive.

If cyclic spray lubrication is used, the operator can modify the volume of lubricant consumed by changing the spray duration and pause time parameters. Resources Process control system Pneumatic energy Dry air Network pressure [bar]: Air flow rate available: Filtered air filtration class: Electrical Every care has been taken to ensure the accuracy of the information contained in this publication but no liability can be accepted for any loss or damage whether direct, The Online Industrial Exhibition.

Open the catalog to page 2. Open the catalog to page 3. Open the catalog to page 5. Open the catalog to page 6. Open the catalog to page 7. Open the catalog to page 8. Multiline pump unit for oil and grease FB? Multiline pump unit for oil and grease FF For reliable machining processes? SKF Electro-pneumatic barrel pump? SKF lubrication solutions for the graphics industry help ensure consistently high quality and can be upgraded. Related Searches Pump with electric motor Mechanical pressure switch Screw-in fitting Compact pump SKF oil pump Pressure switch Threaded level switch Hydraulic directional control valve Compressed air filter Relative humidity sensor Electronic pressure switch Pumping unit In-line flow switch SKF grease lubrication unit Pressure switch with display Oil level switch Minimal quantity lubrication unit Electromechanical lubricator Hydraulically-operated hydraulic directional control valve Multi-point lubricator.

They exclude delivery charges and customs duties and do not include additional charges for installation or activation options. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates. Contact us. Remove all. Compare up to 10 products.To browse Academia. Skip to main content. Log In Sign Up. Properties of Lubricants and Lubrication. Hanif Dewan. Lubrication Composition of lubricating oils: Lubricating oil fractions extracted from crude oil are a widely varying mixture of straight and branched chain paraffinic, napthenic aromatic hydrocarbons having boiling points ranging from about o to oC.

Some specialty lubricants may have gp boiling point extremes of and oC. The choice of g grade of lubricating oil base is determined by the expected use.

When we look at the solid surface it appears smooth to naked eyebut this smooth surface shows irregularities of projections and cavities when viewed under high power microscope. Due Due to this interlockingthere is resistance to the relative motion of the surfaces. This is called the frictional forces or frictional resistance of friction. In due course of motion, the old projections get broken and deformities arise.

The friction between the moving parts of machines also produces heat which causes damage to the machinery. Thus friction causes wear and tear of the moving parts of machinery in contact and due to this cause, the machines lose their efficiency and become useless. Lubricants avoid the damage of the moving parts of machines by minimizing the production of heat.

II Lubricants reduce the wear and tear of machinery by keeping the moving parts of machines apart.

gear lubrication pdf

Lubricants reduce the maintenance and running cost of machine. Lubricants act as the coolant because it reduces the production of heat between the moving parts of machine in contact. Lubricants increases the efficiency of machine by reducing the loss of energy.

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How Engine Lubrication System Works

B using By i ththe llubricants, bi t ththe relative l ti motion ti off th the moving i parts t of machine becomes smooth and noise level of running machine reduces. L bi Lubricants t also l actt as ththe corrosion i preventers. Lubricants also act as a seal as in piston. Lubricant used between piston and walls of the container cylinder prevents the leakage of hot gases produced by the internal combustion i.

Mineral Oil, Eg.

gear lubrication pdf

Graphite, Eg.Technical Editor at Maker Media. Sometimes Scientist.

Solutions for all Lubrication Related Challenges

Builder of things. Maker of stuff. Is your robot grinding to a halt? In general, the most common application of a lubricant is to reduce friction between surfaces, but not all lubricants are equal. Read articles from the magazine right here on Make:.

Get one today. Oils are thin liquids made of long polymer chains, with additives for various extra properties. Common additives include antioxidants to keep the oil from oxidizing, corrosion inhibitors to prevent parts from corroding, and detergents to keep deposits from forming.

These long chains are hard to squeeze out from between surfaces, making oils useful as a slippery barrier between them. The lower the number, the thinner the oil, and the more easily it will flow. While oil can help make things water resistant, it can also absorb water over time.

The more water that absorbs into the oil, the lower its adhesion will be, causing it to wash off of the very parts that need lubrication.

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Greases are made by using oil typically mineral oil and mixing it with thickeners such as lithium-based soaps. They may also contain additional lubricating particles, such as graphite, molybdenum disulfide, or polytetrafluoroethylene PTFE, aka teflon. Greases combine the lubricating properties of oils with added stickiness, allowing the lubricant to adhere to the surfaces better. Greases can even act as a barrier, protecting the surfaces from contaminants that can corrode or damage them.

Like oils, greases come in a range of consistencies, from ketchup-thin to thick like cheddar cheese. When parts move, they can fling grease all around, so it may not be the best option for keeping things clean.

Any shade-tree mechanic would agree that these types of lubricants deserve their own special section. Penetrating lubricants are the saviors of many stuck-bolt combatants, loosening years of rust and debris in minutes. Contrary to the other substances covered here, penetrating oils are not designed for long-lasting lubrication.

Instead, they are low-viscosity oils with additives that are specifically designed for one purpose: to infiltrate the tiny cracks between surfaces such as screw threadsadd lubrication, and break up rust. There are a lot of different penetrating oils out there, but did you know that you can make your own low-cost penetrating oil that outperforms almost all of them?

In an experiment conducted by Drexel University engineering students, they found that a mixture of vegetable oil and acetone works as well or better than WD at loosening stuck bolts.


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