Base oil provides the lubricity and foundation consistency of grease while thickener constitutes the major structure of the grease, giving it a solid to semi-fluid consistency. Additives enhance its performance.
Greases perform their lubrication function over time by staying in place and gradually releasing oil into the working areas of the contact components. This function, performed by a thickener, can be compared to a sponge gradually releasing its liquid when squeezed. Mechanical shear and heat induce the release of its hold of oil.
Although the base oil and additives used to formulate greases are important, the thickener system has its own impact on the performance characteristics of the final product. The fiber structure provided by the thickener determines the mechanical stability and physical properties of the finished product.
Simple thickeners typically provide adequate protection in moderate-temperature applications, while a complex thickener can withstand high operating temperatures and heavier loads. Grease is typically defined as a dispersion of a thickening agent in a liquid lubricant.
Many traditional grease thickeners are formed by reacting an acid with a base to form a soap. This reaction is commonly referred to as saponification and the thickeners formed in this manner are known as soaps, or soap thickeners. A series of intertwined fibers forms a matrix that holds the oil, much in the same manner that a sponge absorbs water. Some non-soap greases trap the oil in a different type of Skip to main content Skip to table of contents.
This service is more advanced with JavaScript available. In our paper we contributed to the understanding of grease lubrication by studying the effect of rheology, thickener particle geometry and thickener concentration on grease EHL films under fully flooded conditions by using commonly available rolling bearing greases varying the thickener — oil systems.
As the complexity of the grease and the internal bearing geometry makes it difficult to study the mechanisms of grease lubrication in full rolling bearings, the research was done using the ball on flat disc configurations with optical interferometry.
The grease film thickness using the single point contact configuration was found to be larger than corresponding bled oil suggesting the presence of thickener in the contact. The film thickness of the greases were found to be independent of rheological properties characterized by steady and dynamic shear.
Therefore, the contribution of the thickener to the film thickness is largest for a high concentration of small particles. Therefore, it is now possible to predict the fully flooded film thickness based on the microstructure of the grease.
Grease seals out harmful contaminants, keeping your equipment protected for maximum performance and minimum downtime. Always keep a close eye on your bearings and apply grease more frequently in extreme wet or heavily loaded conditions. Because of its significant role in keeping equipment protected, it is important to use a high-quality grease product. According to our diesel expert, water contamination comes with common warning signs.
Learn More. Our propane safety expert dives into best practices that can help avoid accidents or setbacks on your operation.
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