Valve unit for internal combustion engine

A valve unit for an internal combustion engine, comprising:

• a duct including an inner tube defining a gas passage therein and an outer tube disposed radially outside of the inner tube, the duct providing an annular liquid storage groove between the inner tube and the outer tube, the duct having a bearing portion, the inner tube defining an axis in an up and down direction;
• a valve disposed in the inner tube, the valve being operable to control the gas passage;
• and
• a shaft supporting the valve and held through the bearing portion of the duct, wherein
• the inner tube includes an overflow portion and an overflow-restricting portion at an upper end thereof,
• the overflow portion being configured to regulate a level of liquid stored in the liquid storage groove and allow excess liquid to overflow from the liquid storage groove,
• the overflow-restricting portion being provided in a predetermined area above the bearing portion and located higher than the overflow portion with respect to an axial direction of the inner tube to restrict the liquid stored in the liquid storage groove from overflowing from the predetermined area above the bearing portion.