摘要 |
The invention provides a ball-and-socket-joint having a ball (18), in which, in order to effectively lubricate the mating surfaces of the ball and socket, a multiplicity of minute depressions (48) are formed on the ball surface for receiving a lubricant during use of the joint, and the boundary between the ball surface and each depression therein is rounded, instead of being sharp-edged, so that the lubricant readily flows into and out of the depressions with the relative angular displacement of the ball. The depression can be effectively formed by barreling or shot blasting. For barreling round or prismatic chips or a mixture may be used. <IMAGE> |