Construction machine

Abstract

An efficient and quiet construction machine has a heat exchanger in which the air flowing out from an axial flow fan avoids collision with the engine. The axial flow fan includes a plurality of blade pieces, a fan ring which guides a flow of air to the axial flow fan, a heat exchanger which is disposed on an upstream side or a downstream side of the flow of air with respect to the axial flow fan, and a structure which is disposed on the downstream side of the flow of air with respect to the axial flow fan. The fan ring includes a suction-side rounded part which reduces a flow channel on a suction side and a discharge-side rounded part which expands the flow channel on a discharge side, and each of the blade pieces is inclined at a sweep forward angle from an axial center toward a rotation direction.

1 . A construction machine comprising: an axial flow fan which includes a plurality of blade pieces and rotates around an axis; a fan ring which is disposed around the axial flow fan and guides a flow of air to the axial flow fan; a heat exchanger which is disposed on an upstream side or a downstream side of the flow of air with respect to the axial flow fan; and a structure which is disposed on the downstream side of the flow of air with respect to the axial flow fan; wherein:
 the fan ring includes a suction-side rounded part which reduces a flow channel on a suction side and a discharge-side rounded part which expands the flow channel on a discharge side;   each of the blade pieces is formed with a leading edge, a trailing edge and a tip, inclined at a sweep forward angle θ from an axial center toward a rotation direction, and attached in a posture in which the blade piece slants forward on the suction side; and   in a state in which the axial flow fan is attached to an inner side of the fan ring, a first intersection where the trailing edge of each of the blade pieces intersects the tip of the same is located within a width range of the discharge-side rounded part;   the sweep forward angle θ is within a range not smaller than 5° and not larger than 25°; and   a second intersection where the leading edge of each of the blade pieces intersects the tip of the same is located to protrude from the suction-side rounded part toward the upstream side of the flow or air, so that;   the air forms a centripetal flow on the upstream side of the axial flow fan, and forms a centrifugal flow on the downstream side of the same to thereby avoid collision with the structure.   
     
     
         2 . A construction machine according to  claim 1 , wherein:
 the plurality of blade pieces are disposed around a columnar hub attached to a rotary shaft of the axial flow fan;   the sweep forward angle θ is defined as an internal angle A of a triangle AOP formed by connecting points A, O and P, where the point A designates a center point of the rotary shaft of the axial flow fan, the point O designates a third intersection where the trailing edge of the blade piece intersects the hub, and the point P designates the first intersection; and   the internal angle A is within a range not smaller than 5° and not larger than 25°.   
     
     
         3 . (canceled)