What is Grease?

Definition of Grease By JIS (Japanese Industrial Standards)

A solid or semi-solid product of dispersion of a thickening agent in lubricating oil. Other ingredients imparting special properties may be included.

Definition of Grease By JIS(Japanese Industrial Standards)

Classification of Lubricants

On the basis of its physical state, grease is classified as semi-solid lubricant.

Grease vs. Oil Lubrication - Advantages and Disadvantages

Item Grease Lubrication Oil Lubrication
Feeding device Grease sealed bearing does not require relubrication for an extended period. Requires a device that continuously feeds oil (drip-feed, splash feed, recirculation system).
Consumption Can be kept to the minimum necessary. Significant amount required.
Lubrication system Simple. Complex.
Leakage Unlikely because of its seal forming characteristics. Possible if sealing system is adequate.
Use for high-speed application Limited. Yes.
Contaminant removal No. Continual removal by filtration or centrifuge.
Cooling efficiency No cooling capacity. High cooling capacity.
Friction loss Generally high, but torque reduction can be achieved by channeling in roller bearings. Generally low.