Idle roller and waterproof bearing seat thereof

The utility model discloses a waterproof bearing seat which comprises a transparent cover sleeved on a roll shaft and a rotary joint connected with the transparent cover, the rotary joint is provided with a connecting end, and the connecting end is installed in an installation hole of the transparent cover in a pluggable mode. The outer edge of the connecting end is sleeved with a first sealing piece used for being pressed on the end face of the transparent cover so that a gap between the connecting end and the mounting hole can be sealed. Thus, under the action of the first sealing piece, a gap at the joint of the rotary joint and the transparent cover is sealed; besides, through the action of a second sealing piece, a third sealing piece and a waterproof edge, a gap at the joint of the transparent cover and the end cover is sealed, cooling water in the idler roller cavity can be prevented from flowing out from the joint of the transparent cover and the rotary joint and the joint of the transparent cover and