Fan driven heat sink

• US 5,494,098 A
• Filed: 06/17/1994
• Issued: 02/27/1996
• Est. Priority Date: 06/17/1994
• Status: Expired due to Term

• Current Assignee: Thermal Form and Function, LLC
• Original Assignee: Wakefield Engineering, Inc.
• Inventors: Morosas, Christopher G.
• Primary Examiner(s): Flanigan, Allen J.
• Application Number:
  US08/261,678
• Time in Patent Office: 620 Days
• Field of Search: 165/80.3, 165/122, 165/121, 165/185, 361/697, 361/709, 29/890.035
• US Class Current: 165/121
• CPC Class Codes: H01L 23/467 by flowing gases, e.g. air H01L23/473 takes precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 29/49359 Cooling apparatus making, e.g., air conditioner, refrigerator

Abstract

A fan driven heat sink assembly which includes a fan assembly mounted on a heat sink for mounting on a microprocessor unit. The heat sink has a solid flat base, a plurality of spaced cooling fins and a housing which is fixed to the base. The cooling fins are fixed to the base and extend from one flat surface of the base to a top wall of the housing. The top wall of the housing has an aperture which is aligned with an outlet opening of the fan assembly. The fins extend from a first end opening at one end of the housing to a second end opening at the opposite end of the housing. Airflow from the fan assembly extends from the opening in the top wall of the housing along the spaces between the fins and out through both end openings of the housing.

Claims

1. A heat sink assembly for use in removal of heat from a heat generating electronic device, said heat sink assembly comprising:

(a) a solid flat base;

(b) a housing which is fixed relative to said base, said housing having a top wall which is spaced from said base, and side walls which extend from said base to said top wall, a first end opening at a first end of said base which is defined by said base, side walls and top wall, a second end opening which is defined by said base, side walls and top wall at a second end of said base which is opposite said first end opening, and an aperture in said top wall which is spaced from said first and second end openings;

(c) a plurality of parallel spaced fins which are fixed to said base, said fins extending from said base to said top wall, said fins defining with said base and said top wall a plurality of channels which extends from said first end opening to said second end opening, the portions of said channels which lie beneath said aperture being open to said aperture; and

(d) a fan assembly which is fixed to said top wall above said aperture for blowing air through said aperture and creating an airflow through said channels from said aperture to each of said first and second end openings.

2. A heat sink assembly as recited in claim 1, wherein said fan assembly comprises:

(a) a fan housing which is fixed to said top wall, said fan housing having a bottom opening at said aperture and a top opening; and

(b) a rotor which has at least one fan blade, said rotor being rotatably mounted within said fan housing between said bottom and top openings.

3. A method of forming a fan driven heat sink assembly comprising the following steps:

(a) folding a length of sheet metal into a continuous serpentine configuration to define a fin assembly which has a plurality of spaced parallel fins, each of said fins being connected to a first adjacent fin by a first end loop at a first end of said fins and connected to a second adjacent fin by a second end loop at a second end of said fins which is opposite said first end;

(b) positioning said fin assembly on the upper surface of a flat metal base so that the first end loops rest on said upper surface and said fins extend vertically from said base;

(c) positioning an inverted U-shaped metal housing on top of the second loops of said fin assembly, said housing having a flat horizontal top wall which rests on said second loop and a pair of vertical legs which lie outside of said pin assembly and which abut said base;

(d) fixing the fin assembly to the top wall of the housing and to the base and fixing the legs of the housing to the base;

(e) forming an aperture in the top wall of the housing to expose portions of said second loops;

(f) severing the exposed portions of said second loops which are below said apertures to expose the spaces between the fins which are below the severed portions of said second loops to said aperture; and

(g) attaching a fan assembly to said top wall above said aperture for blowing air through said aperture against said fins and creating an airflow in the spaces between said fins.

4. A method of forming a fan driven heat sink assembly as recited in claim 3, wherein said fins are fixed to said top wall and to said base by brazing and the legs of said housing are fixed to said base by brazing.

5. A method of forming a fan driven heat sink assembly as recited in claim 3, wherein said housing, said fin assembly and said base are formed essentially of aluminum.

6. A method of forming a fan driven heat sink assembly as recited in claim 3, wherein the upper end portions of said fins are severed are located in a horizontal plane which is spaced from the top wall of said housing to define a plenum chamber below said aperture.

7. A heat sink assembly for use in removal of heat from a heat generating electronic device, said heat sink assembly comprising:

(a) a flat base wall;

(b) a housing which is fixed relative to said base wall, said housing having a top wall which is spaced from said base wall, and side walls which extend from said base wall to said top wall, a first end opening at a first end of said base wall which is defined by said base wall, said side walls and said top wall, a second end opening which is defined by said base wall, said side walls and said top wall at a second end of said base wall which is opposite said first end, and an aperture in said top wall which is spaced from said first and second end openings;

(c) a plurality of parallel spaced fins which are fixed to said base wall, said fins extending from said base wall to said top wall, said fins defining with said base and said top wall a plurality of channels which extends from said first end opening to said second end opening, the portions of said channels which lie beneath said aperture being open to said aperture; and

(d) a fan assembly which is fixed to said top wall above said aperture for blowing air through said aperture and creating an airflow through said channels from said aperture to each of said first and second end openings, said fan assembly comprising;

(1) a fan housing which is fixed to said top wall, said fan housing having a bottom opening at said aperture and a top opening; and

(2) a rotor which has at least one fan blade, said rotor being rotatably mounted within said fan housing between said bottom and top openings, said fan blade being spaced from the fins so as to define a plenum chamber between said blade and said fins.

8. A heat sink assembly as recited in claim 7, wherein the portions of said fins which are directly below said aperture are below the level of said top wall and are vertically spaced from said aperture.

9. A heat sink assembly for use in removal of heat from a heat generating electronic device, said heat sink assembly comprising:

(a) a flat base wall;

(b) a housing which is fixed relative to said base wall, said housing having a top wall which is spaced from said base wall, and side walls which extend from said base wall to said top wall, a first end opening at a first end of said base wall which is defined by said base wall, said side walls and said top wall, a second end opening which is defined by said base wall, said side walls and said top wall at a second end of said base which is opposite said first end, and an aperture in said top wall which is spaced from said first and second end openings;

(c) a plurality of parallel spaced fins which are fixed to said base wall, said fins extending from said base wall to said top wall, said fins defining with said base wall and said top wall a plurality of channels which extends from said first end opening to said second end opening, the portions of said channels which lie beneath said aperture being open to said aperture, said fins being a single continuous length of material which extends transversely of said channels, each of said fins having an upper end which is connected to the upper end of an adjacent fin and a lower end which is connected to the lower end of a different adjacent fin, the portions of said fins which are vertically aligned with said aperture being unconnected at their upper ends so that all of said channels are operatively connected to said aperture; and

(d) a fan assembly which is fixed to said top wall above said aperture for blowing air through said aperture and creating an airflow through said channels from said aperture to each of said first and second end openings.

10. A method of forming a fan driven heat sink assembly comprising the following steps:

(a) forming a heat sink body having a solid base which has a flat horizontal upper surface, said heat sink body having a plurality of spaced parallel fins which are fixed to the base and which extend vertically from said upper surface to upper free ends;

(b) fixing a flat plate to the upper free ends of said fins to form airflow channels which extend from a first end of said plate to a second end of said plate;

(c) forming an aperture in said plate which is spaced from said first and second ends to expose portions of the upper ends of said fins so that portions of said airflow channels are open to said aperture;

(d) reducing the height of the portions of said fins which are vertically aligned with said aperture relative to the remaining portions of said fins to form a plenum chamber below said aperture; and

(e) attaching a fan assembly to said plate, said fan assembly having an outlet opening for airflow which is created by said fan assembly, said outlet opening being operatively connected to said aperture so that air flow from said fan assembly enters said airflow channels from said aperture and proceeds along said airflow channels to each of said first and second ends.

11. A heat sink assembly for use in removal of heat from a heat generating electronic device, said heat sink assembly comprising:

(a) a solid flat base;

(b) a plurality of spared substantially parallel fins which extends vertically from said base to define a plurality of channels between said fins, each of said fins having a lower end which is fixed to said base and an upper end, each of said fins extending horizontally from a first end to a second end, each of said channels having a first end opening at said first end and a second end opening at said second end;

(c) a flat top wall which is fixed relative to said fins and said flat base and abuts the upper ends of said fins, said top wall being parallel to the base and extending from said first end opening to said second end opening, said top wall having an aperture for providing an inlet opening to each of said channels, mid aperture being spaced substantially from each of said first and second end openings so that the portions of each of said channels which extends from each of said first and second end openings to said aperture is a tubular duct which is defined by two adjacent fins, said bottom wall and said top wall; and

(d) a fan assembly which is operatively connected to said aperture for blowing air through said aperture and for creating an airflow within said channels from said aperture to each of said first and second openings.

12. A heat sink as recited in claim 11, wherein each of said first and second outlet openings is defined by said first and last of said plurality of fins, said base and said top wall.