Oil seal cooling device applied to vent hole of gearbox

The invention discloses an oil seal cooling device applied to a vent hole of a gearbox. The oil seal cooling device comprises a installing column internally provided with a through hole, the through hole of the installation column communicates with the vent hole of the gearbox, the through hole of the installation column is a variable-diameter type pore passage, a caliber of the upper part of the through hole is large, an insert is arranged in the through hole of the installing column from the hole opening at the upper part, and the insert is clamped in the middle of the through hole of the installing column; and the insert is of a cover-shaped structure, the top surface of the insert is sealed, exhaust holes are formed in the periphery of the bottom of the insert, an exhaust gap is reserved between the insert and the hole wall of the installing column, the installing column is used for connecting the interior of the gearbox with external atmosphere, the high-temperature oil steam inside the gearbox is discha