FOAMED SOLID LUBRICANT, UNIVERSAL JOINT, PROCESSES FOR PRODUCING THESE, BEARING PRELUBRICATED WITH FOAMED SOLID LUBRICANT, MACHINE ELEMENT PART, AND LUBRICATION SYSTEM

摘要

A foamed solid lubricant which can be used even in places where an external stress such as a compressive or flexing stress is applied and use of a solid lubricant has been difficult; a universal joint; processes for producing the lubricant and joint; a bearing prelubricated with a foamed solid lubricant; a machine element part; and a lubrication system. The foamed solid lubricant is obtained by foaming and curing a mixture comprising a lubricating ingredient, a urethane prepolymer having an isocyanate group in the molecule, a hardener, and a blowing agent. The lubricating ingredient is at least one lubricating ingredient selected among lubricating oils and/or greases. The urethane prepolymer has an isocyanate group content of 2-6 wt.%, excluding 6 wt.%. The blowing agent is water. The mixture contains the lubricating ingredient in an amount of 30-70 wt.% based on the whole mixture. The mixture after foaming has a permeable-void content of 50% or higher.An embodiment of the universal joint is a constant-velocity joint (1), which includes a torque transmission member (ball) (6) and the foamed solid lubricant (10) enclosed in the joint so as to surround the member (6).