Lubrication mechanism

Fig. 10. A model of PVC lubrication mechanism showing (a) PVC adhesion to metal without lubricant (b) surface activity of calcium stearate (c) nonmetal releasing character of paraffin only and (d) synergy between calcium stearate and paraffin (62).

One-shot metered lubrication is eminently suited to oiling systems and can be employed either in an all-loss arrangement or as part of a circulatory system. Sight-glasses or other indicators should be incorporated since such lubricating mechanisms are nowadays so reliable that a blockage or other failure might not be suspected until too late. 

Mechanical-flexing couplings It is important to follow the manufacturer s instructions for lubricating mechanical-flexing couplings, which must be lubricated internally. 

Lubricants. A model for the lubrication mechanism has been developed lliat explains synergy between certain lubricants. Tins model neats lubricants as surface-active agents. Some lubricants have polar ends that arc attracted to other polar ends and to polar PVC flow units and to polar metal surfaces. These also have nonpolar ends that are repelled by the polar groups. Synergy happens when nonpolar Lubricants are added, which are attracted to the nonpolar ends and act as a slip layer. 

Liquid lubrication mechanism. There are four defined regimes of liquid lubrication hydrodynamic (thickness of lubricant film (h), h > 0.25 pm), elastohydrodynamic (h 0.025 to 2.5 pm), boundary (h 0.0025 pm), and mixed. These regimes are dependent on oil viscosity (Z) and relative velocity (V) and are inversely proportional to the load (L), (ZV/L). Fig. 5.1, known as the Stribeck-Hersey curve, depicts these regimes in terms of friction coefficient versus viscosity, velocity, and load (ZV/L) (Fusaro, 1995). 

Lubrication mechanism How do you expect each of the following regimes to change in going from thickness of lubricating film h to a coefficient of friction, p in the Stribeck-Hersey curve Fig.5.1 There are three defined regimes of liquid lubrication (a) hydrodynamic, h 25 pm, (b) elastohydrodynamic, h = 0.025 to... 

Nascent surface Explain the difference in the concept of liquid lubrication mechanism in (a) hydrodynamic, (b) elastohydrodynamic and (c) boundary lubrication. Which of the following characterize (a), (b), and (c) lubrication regime continuous fluid film, negligible deformation, complete separation of the surfaces, elastic and plastic deformation, no wear takes place, no contact between the sliding surfaces, involving surface topography, physical and chemical adsorption, catalysis and reaction kinetics, and tribochemical film formation ... 

Due to these properties, oligoorganosiloxane oils are especially usable for lubricating mechanisms which operate in veiy low or high (sometimes sharply changing) temperatures, e.g. for ball bearings, automatic distribution valves and stuffing boxes, for lubricating pressure molds in the production of plastic masses, rubber technical articles, metalware, etc. 

Kanakia, M.D. and Peterson, M.B., Literature Review of Solid Lubrication Mechanisms, Interim Report BFLRF No. 213, US Army Belvoir Research Development and Engineering Center, November, 1986. (AD A185010). 

Haltner, A.J., An Evaluation of the Role of Vapour Lubrication Mechanisms in MoSj, Wear, 7, 102, (1964). 

Fusaro, R.L., A Comparison of the Lubricating Mechanisms of Graphite Fluoride and Molybdenum Disulfide Films, Proc. 2nd Inti. Conf. on Solid Lubrication, (15 -18 August 1978), ASLE SP-6, p. 59. 

Holinski, R., Lubrication Mechanism of Solid Lubricants in Oils, ASLE Trans., 18, 263, (1975). 

Delacourte, A. Guyot, J.C. Colombo, P. Castellani, P.L. Effectiveness of lubricants and lubrication mechanism in tablet technology. Drug Dev. Ind. Pharm. 1995,2i, 2187-2199. 

Gates, R.S. Hsu, S.M. Silicon-nitride boundary lubrication-lubrication mechanism alcohols. Trib. Trans. 1995, 38 (3), 645. 

Although the frictional sttess increases monotonously with an increase in velocity, the relationship between cr and v is far more complicated than can be expected from the simple lubrication mechanism, which predicts a This... 

Liu XQ, Zhou F, Liang YM (2006) Tribological performance of phosphonium based ionic liquids for an aluminum-on-steel system and opinions on lubrication mechanism. Wear 261 1174-1179... 

Zhang L, Feng DP, Xu B et al (2009) The friction and wear characteristics and lubrication mechanism of imidazole phosphate ionic liquid. Sci China Ser E-Tech Sci 52 1191-1194... 

Apparent viscosity also is used to provide an indication of the directional value of starting and running torques of grease-lubricated mechanisms. Specifications may include limiting values of apparent viscosity for grease to be used at low temperature. 

Kajdas, C. (1987) About an anionic-radical concept of the lubrication mechanism of alcohols. Wear 116 167-180. 

Kench RD. (1999) Helicopter Lubrication. Mechanical Research Department, GKN Westland Hehcopters Ltd. Presented at SAE E-34 Technical Symposium, September 1999. 

Metallic particulates enter the lubricant as a consequence of the breakdown of oil-wetted surfaces due to ineffective lubrication, mechanical working, abrasion. 

The problem with thin fluid film lubrication occurs when the relative motion of the solid surfaces either stops completely, stops at reversal in reciprocating motion or the dynamic loading of a cam on its follower, one gear tooth on another or on a journal within a bearing such that this lubrication mechanism fails and the surfaces make contact. Under boundary lubrication conditions the role of adsorbed molecular films of protective additives is crucial in protecting against wear. 

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