Cooling structure of belt transmission for vehicle

A cooling structure of a belt transmission for vehicles comprising:

• a transmission mechanism including a drive pulley which is driven by a drive shaft of an engine and has a variable pitch diameter, and a driven pulley which is driven by the drive pulley through a drive belt and has a variable pitch diameter;
• a substantially elliptic housing accommodating the belt transmission mechanism and having round walls on its opposite ends to surround the drive pulley and the driven pulley;
• a cooling fan formed on the drive pulley;
• an intake port formed in the vicinity of a suction part of the cooling fan of the housing for forcedly introducing air from an outside into the housing;
• an exhaust port formed in the vicinity of the driven pulley of the housing for exhausting the air cooling an inside of the housing to the outside,
• wherein the exhaust port is provided on the housing in a direction normal to a longitudinal axis of the driven pulley at the rearward of a center of rotation of the driven pulley as seen from a side;
• and
• a guide portion having a guide wall portion and a weir portion is formed on a connecting portion of the exhaust port to the housing so that it may introduce a mainstream of cooling air, which is forcedly supplied into the housing by the cooling fan, into the exhaust port and;
• the guide wall portion originating in a lower end of an inlet end of the exhaust port extends toward the outlet of the exhaust port in a direction tangent to an internal wall of the housing,
• the weir portion is formed in succession to a terminal end of the guide wall portion and extends in a direction normal to the guide wall portion to come into the internal wall of the housing.