Patent attributes
A boot for a universal joint is constructed by a boot body and a boot adapter. The one end of the boot is fitted on a propeller inner shaft via its one-end fitting portion and the other end of the boot is fitted on the outer race of the universal joint via its other-end fitting portion, thereby substantially covering the universal joint. The foregoing one-end fitting portion has an annular lip portion at its end portion. Passages for flowing air between the inside of the boot and the outside of the boot are formed on the one-end fitting portion and the annular lip portion. The passages are closed by the annular lip portion being expanded in diameter outward by a centrifugal force caused by the high rotation of the propeller inner shaft, thereby preventing splashed water or muddy water from intruding into the boot when air is sucked into the boot.
