Heat sink and heat sink fan

Patent metadata

Field	Value
Publication number	US-9252073-B2
Application number	US-201313783469-A
Country	US
Kind code	B2
Filing date	Mar 4, 2013
Priority date	Nov 19, 2012
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Each fin of a heat sink includes a main fin connected to a core and extending radially outwards, and a pair of branch fins extending radially outwards from a branch point at a radially outer end of the main fin. Among a plurality of fins, in each of three fins which are adjacent in the circumferential direction, a width of an end portion of the main fin viewed along the center axis expands radially outwards at an angle which is larger than an expanding angle of the pair of branch fins. A difference between a distance from the center axis to the branch point in the center one of the fins and a distance from the center axis to the branch point in each of the other two fins is equal to or larger than a width of a root of the main fin in the center radiating fin.

First claim

What is claimed is:

1. A heat sink comprising:
a plurality of fins arranged radially about a center axis and spaced away from one another, the plurality of fins extending outward in a radial direction perpendicular or substantially perpendicular to the center axis; and
a core arranged to couple and to support inner sides of the plurality of fins; wherein
each of the plurality of fins includes:
a main fin connected to the core and extending radially outwards; and
a pair of branch fins which are branched in a circumferential direction from a branch point as a radially outer end of the main fin, and which extend radially outwards;

among the plurality of fins, in each of three fins which are adjacent in the circumferential direction, a width of an end portion including the end of the main fin viewed along the center axis expands radially outwards at an angle which is larger than an expanding angle of the pair of branch fins;
among the three fins, a difference between a distance from the center axis to the branch point in the center one of the fins and a distance from the center axis to the branch point in each of the other two fins is equal to or larger than a width of a root of the main fin in the center one of the fins; and
in an innermost branch radiating fin of which the branch point is positioned on an innermost side among the three fins, a value obtained by dividing a distance between ends of the air of branch fins by a length of the branch fin is smaller than a value obtained in the same way in a radiating fin which is adjacent to the innermost branch radiating fin anon the three fins.

2. A heat sink according to claim 1 , wherein in the innermost branch radiating fin, a value obtained by dividing a distance between the pair of branch fins in an arbitrary radial position with the center axis as the center by a length of the branch fin along the radial direction from the branch point to the arbitrary radial position is smaller than a value obtained in the same way in the radiating fin which is adjacent to the innermost branch radiating fin among the three fins.

3. A heat sink according to claim 1 , wherein in an innermost branch radiating fin of which the branch point is positioned on the innermost side among the three fins, an angle defined by two line segments which connect the branch point and two intersection points with a circle having an arbitrary radius with the center axis as the center in two surfaces of the pair of branch fins which are opposed to each other is smaller than an angle obtained in the same way in a radiating fin which is adjacent to the innermost branch radiating fin among the three fins.

4. A heat sink according to claim 1 , wherein
in each of the plurality of fins, a width of the end of the main fin viewed along the center axis expands radially outwards at an angle larger than an expanding angle of the pair of branch fins; and
among the plurality of fins, in each combination of two fins which are adjacent to each other, a difference between a distance from the center axis to the branch point in one of the fins and a distance from the center axis to the branch point in another one of the fins is equal to or larger than the width of the root of the main fin in the one of the fins.

5. A heat sink according to claim 1 , wherein a distance between ends of branch fins in the center one of the fins and each of the other two fins is larger than a distance between ends of the pair of branch fins in each of the three fins.

6. A heat sink according to claim 1 , wherein
in the plurality of fins, a region on the inner side from a predetermined radius with the center axis as the center protrudes downwards; and
the branch point of an innermost branch radiating fin of which the branch point is positioned on the innermost side of the three fins is positioned farther on the inner side than the predetermined radius.

7. A heat sink according to claim 1 , wherein a width of each branch fin viewed along the center axis is constant or substantially constant over a full length in the radial direction.

8. A heat sink according to claim 1 , wherein the plurality of fins extend radially outwards in a straight manner.

9. A heat sink according to claim 1 , wherein a center portion of the core contains a copper alloy, and an outer edge portion of the core and the plurality of fins contain an aluminum alloy.

10. A heat sink according to claim 1 , wherein the heat sink is produced by extrusion molding or pultrusion molding which utilizes a dividing die and a heat sink fabricating die.

11. A heat sink fan, comprising:
a heat sink of claim 1 ; and
a fan arranged to send an air to the heat sink.

Assignees

• Nidec Corp

Inventors

• Yamashita Takamasa
• Nakae Nobuya

Classifications

• H10W40/226

  characterised by projecting parts, e.g. fins to increase surface area (leadframes for cooling H10W70/461) · CPC title

• H10W40/43 Primary

  by flowing gases, e.g. forced air cooling · CPC title

• H01L23/467 Primary

  Electricity · mapped topic

• H01L2924/00

  Electricity · mapped topic

• H01L23/3672

  Electricity · mapped topic