Maximum period of reliable service of lubricating greases

Krakhmalev, S. I.; Кузнецов, А. А.; Karusevich, R. S.; Moiseikina, N. N.

doi:10.1007/bf00727194

Cited by 2 publications

(2 citation statements)

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“…This degradation (or ageing) manifests itself in a mechanical destruction of grease molecules within the contact zone, and in temperatureaccelerated chemical changes that lead to the appearance of various deposits and oxidation products, to the alteration of viscosity and lubricity, and to oil bleeding, affecting both friction and wear [14−17]. Interestingly, though there were successful attempts to predict maximum period of reliable service of grease [18], due to a high complexity of the processes involved, the effects of ageing are determined today solely based on experimental techniques.…”

Section: Introductionmentioning

confidence: 99%

Assessing workability of greased bearings after long-term storage

et al. 2018

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Here, we developed a technique to assess the workability of sealed-for-life greased rolling bearings after a long-term storage. In this framework, we devised a model of equivalent transition between the conditions of natural ageing under daily and seasonally fluctuating temperature, and the conditions of accelerated thermal ageing at a constant high temperature. The tested bearings were thermally aged, and then their steady state friction and outer ring temperature were examined in a custom high-speed spindle. These results were compared to the performance of a reference new bearing tested under the same loading conditions. Our findings suggest that long-term storage can significantly degrade the performance of sealed-for-life greased rolling bearings. However, a proper running-in can substantially deter the ageing-driven degradation of the bearings.

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Section: Introductionmentioning

confidence: 99%

Assessing workability of greased bearings after long-term storage

et al. 2018

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“…In continuous multiyear (10 years and more) operation of machines and mechanisms and the impossibility of changing or replenishing the grease, it is necessary to not only estimate the operating life of a grease material but also its lifetime -the shelf life [17].…”

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confidence: 99%

Effect of a change in the properties of plastic grease in storage in a container and in an article on the reliability of operation of friction units

Krakhmalev

Shkol’nikov

Platonova

2010

Chem Technol Fuels Oils

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Structural formation of plastic greases, which are essentially colloidal systems, during their fabrication and the factors that affect aging of lubricants during storage in containers and use in friction units are examined. The results of an analysis of the quality of the greases after prolonged use in friction units in different types of engineering are reported.The permissible effective operating life of plastic grease (PG) in a friction unit without changing and replenishing it determines the economy and reliability of use of the technology. Without knowing this, it is impossible to establish the schedule for changing or replenishing grease material in the friction units of mechanisms.During storage of an article, grease materials age much more rapidly than the parts of the friction unit. The lifetimes of the individual kinds of equipment are due to the permissible calendar operating life of the grease material to a significant degree.The in-service time of grease, during which it remains effective and totally ensures the initially established greasing conditions, the friction coefficient, and also the intensity of wear, is a function of a combination of the type of friction, kinematics of movement of conjugated parts, their temperature, load, and speed, design, and the periodicity of operation of the unit. Prolonged use of grease materials is accompanied by worsening of their functional properties, called "aging." Aging of PG is a complex multifactor process of interrelated changes in their composition, ratio of components, and as a consequence, structure and properties of the colloidal system [1]. As aging progresses, products of friction, tribochemical transformation, reaction of the components of the grease with the metal surfaces of the unit, the surrounding gas medium, and moisture, as well as the ingredients that initially arise during formation of the plastic system, accumulate in the grease. In formation of even an insignificant amount of products of oxidation and tribodestruction of the initial components, the plastic grease can lose the initial volumetric mechanical properties and not satisfy the requirements for use.

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Maximum period of reliable service of lubricating greases

Cited by 2 publications

References 0 publications

Assessing workability of greased bearings after long-term storage

Assessing workability of greased bearings after long-term storage

Effect of a change in the properties of plastic grease in storage in a container and in an article on the reliability of operation of friction units

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