Abstract: A refrigerant channel of a heatsink includes an upwardly inclined channel formed by a side wall for downstream side of a first protruding portion and a side wall for upstream side of a second protruding portion. The upwardly inclined channel directs a flow of the refrigerant toward a base portion of the fin and causes the refrigerant to flow into the fin region, because of which more refrigerant flows to the base portion than to a leading end portion of the fin, and a high heat dissipating performance is obtained. Also, the fin is a columnar body whose sectional form perpendicular to a central axis is a regular hexagon, has rounded portions in corner portions, and has tapers on side faces. Six fins are disposed neighboring one fin, and a distance between fins is constant. Because of this, the heat dissipating performance further improves, and pressure loss can be reduced.

Abstract: A refrigerant channel of a heatsink includes an upwardly inclined channel formed by a side wall for downstream side of a first protruding portion and a side wall for upstream side of a second protruding portion. The upwardly inclined channel directs a flow of the refrigerant toward a base portion of the fin and causes the refrigerant to flow into the fin region, because of which more refrigerant flows to the base portion than to a leading end portion of the fin, and a high heat dissipating performance is obtained. Also, the fin is a columnar body whose sectional form perpendicular to a central axis is a regular hexagon, has rounded portions in corner portions, and has tapers on side faces. Six fins are disposed neighboring one fin, and a distance between fins is constant. Because of this, the heat dissipating performance further improves, and pressure loss can be reduced.