Blower unit

Abstract

A blower unit has a first axial fan and a second axial fan for generating a flow of cooling air passing through a heat exchanger disposed under an intake duct through which an intake air to be introduced to an engine flows. The first axial fan and the second axial fan are aligned in a substantially horizontal direction downstream of the heat exchanger with respect to the flow of air. A first rotation axis of the first axial fan and a second rotation axis of the second axial fan are perpendicular to the heat exchanger and located lower than a center of the heat exchanger. The first axial fan, which is disposed on a right side of the second axial fan, rotates in a clockwise direction and the second axial fan rotates in a counterclockwise direction when viewed from a downstream position with respect to the flow of air.

1 . A blower unit for generating cooling air passing through a heat exchanger that is disposed under an intake duct through which intake air to be introduced to an internal combustion engine flows, the blower unit comprising:
 a first axial fan having a first rotation axis substantially perpendicular to the heat exchanger; and   a second axial fan having a second rotation axis substantially perpendicular to the heat exchanger, wherein   the first axial fan and the second axial fan are aligned in a substantially horizontal direction downstream of the heat exchanger with respect to a flow of cooling air such that the first axial fan is on a right side of the second axial fan when viewed from a downstream position with respect to the flow of cooling air,   the first axial fan and the second axial fan are disposed such that the first rotation axis and the second rotation axis are lower than a center of the heat exchanger, and   the first axial fan is configured to rotate in a clockwise direction and the second axial fan is configured to rotate in a counterclockwise direction when viewed from the downstream position.   
   
   
       2 . The blower unit according to  claim 1 , further comprising:
 a shroud including a first ring portion, a second ring portion and an air introducing portion, wherein   the first ring portion has a substantially cylindrical shape defining a first fan opening therein, the first axial fan is disposed in the first fan opening,   the second ring portion has a substantially cylindrical shape defining a second fan opening therein, the second axial fan is disposed in the second fan opening,   the air introducing portion extends from the first ring portion and the second ring portion toward an upstream position with respect to the flow of cooling air and defines an air passage introducing the cooling air passing through the heat exchanger toward the first fan opening and the second fan opening, a cross-sectional area of the air passage increasing toward the upstream position, and   the first ring portion and the second ring portion are disposed such that upper ends thereof are located lower than an upper end of the heat exchanger.   
   
   
       3 . The blower unit according to  claim 2 , wherein
 the shroud includes an air guide portion extending from the first ring portion and the second ring portion toward the downstream position with respect to the flow of cooling air,   the air guide portion is configured to lead the cooling air passing through the first and second ring portions in a downward direction.   
   
   
       4 . The blower unit according to  claim 3 , wherein the air guide portion has a diffuser shape. 
   
   
       5 . The blower unit according to  claim 3 , wherein the air guide portion has a bell-mouth shape. 
   
   
       6 . The blower unit according to  claim 2 , wherein
 the air introducing portion is configured such that an axis of the air passage defined in the air introducing portion is inclined downward with respect to the flow of cooling air.   
   
   
       7 . The blower unit according to  claim 6 , wherein
 the air introducing portion has an upper wall and a lower wall,   the upper wall extending between an upper portion of the heat exchanger and upper portions of the first and second ring portions,   the lower wall extending between a lower portion of the heat exchanger and lower portions of the first and second ring portions,   the upper wall is inclined downward toward the upper portions of the first and second ring portions, and   the lower wall extends substantially horizontally.   
   
   
       8 . The blower unit according to  claim 1 , wherein
 the first axial fan and the second axial fan are disposed such that a middle point between the first rotation axis and the second rotation axis is located under the intake path with respect to an up and down direction.   
   
   
       9 . The blower unit according to  claim 1 , wherein
 each of the first axial fan and the second axial fan includes a boss part and a plurality of blades extending from the boss part in a radially outward direction, and   each of the blades has a sweepforward shape inclined in a direction of rotation.   
   
   
       10 . An arrangement structure of a blower unit comprising:
 an intake duct defining an intake air passage through which intake air to be introduced to an internal combustion engine flows;   a heat exchanger oriented in an up and down direction, the heat exchanger including a core performing heat exchange between cooling air flowing outside of the heat exchanger and an internal fluid flowing inside of the heat exchanger; and   a first axial fan disposed behind the heat exchanger and having a first rotation axis perpendicular to the heat exchanger; and   a second axial fan disposed behind the heat exchanger and having a second rotation axis perpendicular to the heat exchanger, wherein   the first axial fan is located on a right side of the second axial fan when viewed along a direction perpendicular to the heat exchanger,   the intake duct is disposed to extend above the first and second axial fans,   the first axial fan and the second axial fan are arranged such that the first rotation axis and the second rotation axis are lower than a center of the core of the heat exchanger,   the first axial fan is configured to rotate in a clockwise direction, and   the second axial fan is configured to rotated in a counterclockwise direction.   
   
   
       11 . The arrangement structure according to  claim 10 , wherein
 a gap Δh between the center of the core and the first and second rotation axes in the up and down direction and a vertical dimension H of the core satisfy a relationship of Δh≧10/H.   
   
   
       12 . The arrangement structure according to  claim 10 , further comprising:
 a shroud including a first ring portion, a second ring portion, an air introducing portion and an air guide portion, wherein   the first axial fan is disposed in the first ring portion,   the second axial fan is disposed in the second ring portion,   the air introducing portion extends from the heat exchanger to the first and second ring portions, and defines an air passage space therein for leading the cooling air from the heat exchanger toward the first and second ring portions,   the air introducing portion includes an upper wall extending from an upper portion of the heat exchanger to upper portions of the first and second ring portions and inclining downward toward the first and second ring portions,   the air guide portion extends from the first and second ring portions toward a downstream position with respect to a flow of cooling air, and   the air guide portion is inclined downward toward the downstream position.