Grease for high-speed bearing

Abstract

A grease for a high-speed bearing which can sufficiently accommodate high-speed rotation with a dmN value of 1,700,000 or above and which enables compactification of machine tools and operating cost reduction, more specifically, a grease for high-speed bearings which comprises both a urea grease containing a urea compound as the thickening agent and a non-urea grease containing a composite amide lithium soap having an amide linkage in the molecule as the thickening agent, wherein the urea compound is a compound prepared by reacting a polyisocyanate component with a monoamine component, with the monoamine component containing an aliphatic monoamine in an amount of 46% by mole or above of the whole monoamine component.

Description

technical field [0001] The present invention relates to a grease for high-speed bearings used in rolling bearings that support high-speed rotating shafts such as machine tool spindles. Background technique [0002] For the main shaft of the machine tool, in order to improve the processing efficiency, the main shaft rotating at high speed is preferred, and various lubrication technologies are used in the bearing. As a lubrication method suitable for a high-speed rotating spindle, for example, methods such as oil mist lubrication, air oil mist lubrication, and jet lubrication are known. However, these lubrication methods must have ancillary equipment such as compressed air or an oil supply device, which is one of the reasons for the increase in the initial cost and operating cost of the working machine. On the contrary, grease lubrication can be said to be the preferred lubrication method due to the low necessity of maintenance. For example, examples of high-speed rolling be...

AI Technical Summary

Problems solved by technology

[0010] (b) With regard to low torque performance (inhibition of temperature rise), the existing grease for high-speed bearings, as mentioned above, should suppress the viscosity of the base oil to a low value, but there is a problem that when the bearing rotates at high speed, Viscosity decreases significantly due to temperature rise, and an oil film with the thickness necessary for lubrication cannot be formed

With the increase in the rotational speed of such bearings, it is difficult to fully satisfy the performance required by the bearings with existing greases.

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