Cooling device

Abstract

A cooling device to which a heating element is joinable includes a base, a plurality of first groups of pin fins and a plurality of second groups of pin fins. The second groups and the first groups are arranged alternately in a flow direction in which a cooling medium flows through a passage of the base. A second outermost pin fin of each second group is more distant from a side surface of the base than a first outermost pin fin of each first group. Width between a side surface of the second outermost pin fin of each second group and the side surface of the base is the same as or larger than width between a side surface of the pin fin of each first group that is adjacent to the first outermost pin fin of the first group and the side surface of the second outermost pin fin.

What is claimed is: 
     
         1 . A cooling device to which a heating element is joinable, comprising:
 a base having a passage through which a cooling medium flows;   a plurality of first groups of pin fins located in the passage and adjacent to the heating element, wherein the pin fins of each first group are arranged in a width direction that is perpendicular to a flow direction in which the cooling medium flows through the passage, wherein one of the pin fins of each first group that is located closest to a side surface of the base in the first group is a first outermost pin fin; and   a plurality of second groups of pin fins located in the passage and adjacent to the heating element, wherein the pin fins of each second group are arranged in the width direction that is perpendicular to the flow direction in which the cooling medium flows through the passage, wherein one of the pin fins of each second group that is located closest to the side surface of the base in the second group is a second outermost pin fin, wherein the second groups and the first groups are arranged alternately in the flow direction, wherein the pin fins of the second groups and the first groups are provided in a staggered arrangement, wherein the second outermost pin fin of each second group is more distant from the side surface of the base than the first outermost pin fin of each first group, wherein width between a side surface of the second outermost pin fin of each second group and the side surface of the base is the same as or larger than width between a side surface of the pin fin of each first group that is adjacent to the first outermost pin fin of the first group and the side surface of the second outermost pin fin.   
     
     
         2 . The cooling device according to  claim 1 , wherein width between a side surface of the first outermost pin fin and the side surface of the second outermost pin fin is the same as the width between the side surface of the pin fin of each first group that is adjacent to the first outermost pin fin of the first group and the side surface of the second outermost pin fin. 
     
     
         3 . The cooling device according to  claim 1 , wherein the first outermost pin fin is a projection that is formed projecting from the side surface of the base. 
     
     
         4 . The cooling device according to  claim 3 , wherein the projection is formed so that a cross section thereof is reduced gradually toward an end thereof. 
     
     
         5 . The cooling device according to  claim 1 , wherein the heating element is a semiconductor device that is joined to the base via an insulating base plate.