CORRUGATED-FIN TYPE RADIATOR

Abstract

Disclosed is a corrugated-fin type radiator (1), which comprises corrugated fins (10), and a support substrate (20) having a plurality of fixing grooves (23) defined by side walls (24) and a bottom (25). The bottom (25) has a ridge (26) at least in its portion, and the side walls (24) are formed of a vertical wall (24a), a tapered wall (24b) and a corner (24c). A fin fixing portion (14) is fixed along the side walls (24) and the bottom (25) of the fixing grooves (23). Also disclosed is a method for manufacturing the corrugated-fin type radiator (1), which comprises a substrate manufacturing step, a fin shaping step and a fixing step. Thus, it is possible to provide the corrugated-fin type radiator capable of improving a radiation efficiency, and a method for manufacturing the radiator.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radiator for cooling, for example, a semiconductor element such as a transistor, an LSI, and a microprocessor, that generates heat during operation, and in particular to a corrugated-fin type radiator including corrugated fins.

2. Description of the Related Art

There are various types of radiators in general for cooling a semiconductor element. A corrugated-fin type radiator is known, in which corrugated fins are disposed on the support substrate on which a semiconductor element is mounted, thereby expanding the radiation area and improving the cooling effect.

A conventional corrugated-fin type radiator is, for example, disclosed in JP3602806. Hereinafter such a conventional corrugated-fin type radiator will be explained with reference to FIGS. 4A to 4B. FIG. 4A shows a structure in which a conventional corrugated-fin type radiator having a fin fixing portion of the corrugated-fin is fixed on a fixing groove. FIG. 4B is a partially enlarged sectional view of the fixing groove and its vicinity on which the fin fixing portion is fixed. As shown in FIG. 4A, a conventional corrugated-fin type radiator 100 is mainly formed of a corrugated fin 110 and a support substrate 120 with a plurality of fin-fixing grooves 123. The fin-fixing groove 123 includes a flat bottom 125, tapered walls 124 spreading from an opening side, and corners 127 with a curved surface between the tapered wall 124 and the bottom 125. A corrugated fin fixing portion 114 of the corrugated fin 110 includes a projecting portion 111 which is a lower end part of 114 projecting toward the fin-fixing groove 123, and is so formed as to have the width smaller than the minimum width of the opening side of the fin-fixing groove 123.

By pressing the corrugated fin fixing portion 114 toward the fin-fixing groove 123 with a press fitting blade 132 which has a flat lower end, the projecting portion 111 is deformed and is pressure-bonded along the shape of the fin-fixing groove 123, thereby the corrugated fin fixing portion 114 being fixed in the fin-fixing groove 123.

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

However, the corrugated-fin type radiator 100 described above still have a room for improvement. In the technical field of radiators, it is required to improve radiation efficiencies. For this purpose, an important issue is to increase the contact area and adhesion force between corrugated fins and a support substrate.

In light of this background, a conventional corrugated-fin type radiator 100, as shown in FIG. 4B, gaps S may be formed because the corrugated fin fixing portion 114 cannot be expanded to corners 127 of the fin-fixing groove 123 with poor contact along with the corners 127.

In addition, in the conventional corrugated-fin type radiator 100, when the projecting portion 111 of the corrugated fin fixing portion 114 is pressed with the press fitting blade 132 of which lower end is flat, the projecting portion 111 is deformed and spreads in a width direction of the fin-fixing groove 123, and when it reaches the corner 127, then it is pressed up in a height direction and deformed. Due to this deformation, a central part of the corrugated fin fixing portion 114 might rise and gaps S might be formed between the projecting portion 111 and the bottom 125 of the fin-fixing groove 123.

Accordingly, it is desirable to provide a corrugated-fin type radiator that can increase the contact area and adhesion force between the corrugated fins and the support substrate, and thereby improving the radiation efficiency.

Means for Solving the Problems

The present invention is a corrugated-fin type radiator including: corrugated fins that radiate heat; and a support substrate having a plurality of fixing grooves including side walls and a bottom for fixing a part of the corrugated fins; wherein the bottom has a ridge on at least a part thereof, which is higher than the bottom and is formed in parallel to the bottom, and the side walls have vertical walls extending downward from the support substrate in a vertical direction, tapered walls extending from the vertical walls toward the bottom with increase in a distance between the tapered walls, and corners having a curved surface formed contiguously from the tapered walls to the bottom, and wherein a part of the corrugated fin is fixed along the shape of the side wall and the bottom of the fixing groove.

According to the present invention, as the corrugated-fin type radiator has a ridge at least in one part of the bottom, a part of the corrugated fin is pressed by the ridge and is expanded first along the shape of the ridge. Then it is expanded along the shape of the bottom, and expanded to the side walls of the fixing groove. Thus owing to the ridge, the contact area between the corrugated fin and the support substrate can be increased. In addition, due to the ridge, the deformation quantity of the corrugated fin can be increased, thereby the pressing force applied on the corrugated fin toward the corner and the side wall located on both sides of the fixing groove are also increased. As a result, a part of the corrugated fin can be fixed on the fixing groove appropriately. Further, since the side wall of the fixing groove has a vertical wall and a tapered wall, apart of the corrugated fin can be fit and fixed into the fixing groove and a part of the corrugated fin is appropriately attached to the side wall according to the lateral-directional force between the adjacent corrugated fins. In this way, fixing a part of the corrugated fin according to the shape of the side wall and bottom of the fixing groove, the contact area between the corrugated fin and the support substrate is increased. Further, since the side wall has a corner with a curved surface, a part of the corrugated fin, which is expanded toward the corner, presses the corner, and the fixing strength of the corrugated fin to the support substrate is improved.

Preferably, but not necessarily, the length of the vertical wall is made greater than or equal to one sixth and smaller than or equal to a half of the length of the side wall, the height of the ridge is made greater than or equal to one tenth and smaller than or equal to two thirds of the height of the fixing groove, the width of the lower end part of the ridge is made greater than or equal to one tenth and smaller than or equal to five sixths of the width of the fixing groove, the width of the upper part of the ridge is made greater than or equal to one eighth and smaller than or equal to four fifths of the width of the lower end part of the ridge, and the width of the upper end part is made smaller than or equal to the width of the lower end part.

In this structure, a part of the corrugated fin can be appropriately fixed in a shape in accordance with the side wall, the bottom and corner, without applying an excessive force.

The radius of the corner is preferably, but not necessarily, made to be greater than or equal to one sixteenth and smaller than or equal to one third of the width of the fixing groove.

In this structure, a part of the corrugated fin can be fixed on the corner more appropriately.

A manufacturing method according to an aspect of the present invention is a method for manufacturing a corrugated-fin type radiator described in claim 1, including a substrate manufacturing step, a fin shaping step and a fixing step.

The method of producing a corrugated-fin type radiator according to the present invention includes: a substrate manufacturing step of extruding or cutting the support substrate, forming the plurality of fixing grooves which is formed of, the side wall having the tapered wall and the corner, and of the bottom, and forming the ridge on the bottom; a fin shaping step of producing a corrugated fin by folding a metal plate to form a plurality of fin bottoms which form a lower end of the corrugated fin and are substantially parallel to the support substrate, a plurality of fin top portions which form an upper end of the corrugated fin and are substantially parallel to the support substrate, and a plurality of jointing portions which joint the fin bottom and the fin top portion and which are substantially perpendicular to the support substrate, so that the fin bottoms and the fin top portions are arranged one after the other, and so that the distance between external walls of the neighboring jointing portions is approximately equal or somewhat smaller than the opening width of the fixing groove; and a fixing step of fixing the corrugated fin on the support substrate by, inserting the fin fixing portion, which is formed of the fin bottom and a lower end of the jointing portion, into the fixing groove from the opening, fitting the fin fixing portion onto the ridge, and pressing the fin bottom toward the ridge from the gap of the jointing portion using the top of a press tool having a concave portion on top thereof, and deforming the fin fixing portion along the shape of the fixing groove, thereby the corrugated fin being fixed on the support substrate.

Effect of the Invention

According to the present invention, the following effects can be obtained. The corrugated-fin type radiator according to the invention is capable of increasing the contact area between the corrugated fin and the support substrate, and improving the heat conduction efficiency between the support substrate and the corrugated fin. Herewith the radiation efficiency of the corrugated-fin type radiator is improved, and the fixing strength of the corrugated fin to the support substrate is also improved.

In addition, according to the method for manufacturing a corrugated-fin type radiator of the present invention, the fin fixing portion is deformed along the shape of the fixing groove, thereby the contact area and the adhesion force between the corrugated fin and the support substrate are increased, and therefore the radiation characteristics of the corrugated-fin type radiator can be improved. Further, the fixing strength of the corrugated fin to the support substrate is also improved. In addition, fitting and fixing the corrugated fin on the support substrate can be performed without any special tools and the component count of a radiator can be reduced which leads to the cost reduction of the radiator.

The various aspects, other advantages and further features of the present invention described above will become more apparent by describing in detail illustrative, non-limiting embodiments thereof with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an entire block diagram of a corrugated-fin type radiator in accordance with an embodiment of the present invention;

FIG. 1B shows a partially enlarged perspective view of the fixing groove shown in FIG. 1A;

FIG. 2 shows a partially enlarged sectional view of the vicinity of the fixing groove shown in FIG. 1;

FIGS. 3A to 3C show explanatory diagrams for explaining how corrugated fins are fixed to the fixing grooves;

FIG. 4A shows a conventional corrugated-fin type radiator having the fin fixing portion of the corrugated fin fixed on the fixing groove; and

FIG. 4B shows a partially enlarged sectional view of the vicinity of the fixing groove with the fin fixing portion thereof being fixed.

DESCRIPTION OF THE SYMBOLS

• • 1 corrugated-fin type radiator
  • 10 corrugated fin
  • 11 fin bottom
  • 12 fin top portion
  • 13 jointing portion
  • 14 fin fixing portion
  • 15 outermost fin bottom
  • 20 support substrate
  • 21 upper surface
  • 22 lower surface
  • 23 fixing groove
  • 24 side wall
  • 24a vertical wall
  • 24b tapered wall
  • 24c corner
  • 25 bottom
  • 26 ridge
  • 28 engaging portion
  • 28a engaging side wall
  • 28b engaging bottom
  • 29 clamping portion
  • 31, 32 press tool
  • 31a concave portion

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of a corrugated-fin type radiator 1 according to the present invention will be described with reference to the drawings.

As shown in FIG. 1A, a corrugated-fin type radiator 1 includes corrugated fins 10 for radiating heat, and a support substrate 20 having a plurality of fixing grooves 23 thereon which is formed of a side wall 24 and a bottom 25 for fixing a part of the corrugated fin 10. The corrugated fin 10 and the support substrate 20 are made of high thermal conductive materials such as copper, copper alloy, Al alloy and the like.

The corrugated fin 10 includes, a fin bottom 11 which is nearly parallel to the support substrate 20 and forms the lower end of the corrugated fin, a fin top portion 12 which is nearly parallel to the support substrate 20 and forms the upper end of the corrugated fin 10, and a jointing portion 13 which is substantially vertical to the support substrate 20 and couples the fin bottom 11 and the fin top portion 12. The fin bottoms 11 and the fin top portions 12 are arranged one after the other.

The corrugated fin 10 can be shaped by folding a long metal plate trough press forming. Meanwhile, in this embodiment, as shown in FIG. 1A and FIG. 2, the corrugated fin 10 does not have a jointing portion 13 at the outermost part thereof, and the outermost fin bottom 15 is made shorter than other fin bottoms 11 (see FIG. 2).

In addition, there is no restriction in the height of the jointing portion 13 of the corrugated fin 10 from the support substrate 20 as long as it is high enough for obtaining the radiation effect. Further, a width W1 of the corrugated fin 10 may be smaller or greater than the width of support substrate 20, and not restricted specifically. Still further, the thickness of the corrugated fin 10 may be determined as appropriate in light of the strength and so on.

According to this embodiment, in the corrugated fin 10, the fin bottom 11 and the lower end of the jointing portion 13, 13, which are contiguously formed from both ends of the fin bottom 11 in the longitudinal direction, are fixed along the shape of the fixing groove 23. Hereinafter, this portion may be referred to as “fin fixing portion” for convenience in the explanation. The fin fixing portion 14 is formed so that the width of the fin fixing portion 14 (see FIG. 2), that is the width between the external walls of the jointing portion 13, is nearly equal to or slightly smaller than the width of the opening of the fixing groove 23, that is the width between the side walls 24, 24. Herewith, the fin fixing portion 14 can be inserted smoothly into the fixing groove 23.

As shown in FIGS. 1A and 1B, the support substrate 20 acts as a base of the corrugated-fin type radiator 1, and has a plurality of fixing grooves 23 having a width and depth prescribed for fixing the corrugated fin 10 on the upper surface 21. In addition, the support substrate 20 abuts to a heat source such as a semiconductor element (not shown), and conducts the heat from the heating element to the corrugated fin 10.

As shown in FIG. 1B, the plurality of fixing grooves 23 having the side wall 24 and the bottom 25 are formed from the upper surface 21 to the lower surface 22 on the support substrate 20.

The side wall 24 is formed of, a vertical wall 24a which extends downward perpendicularly to the upper surface 21 of the support substrate 20, a tapered wall 24b formed from the vertical wall 24a toward the bottom 25 increasing in diameter, and a corner 24c having a curved surface formed contiguously from the lower end portion of the tapered wall 24b.

It is preferable for a length L1 of the vertical wall 24a to be greater than or equal to one sixth and smaller than or equal to one half of a length L2 of the side wall 24. If the length L1 of the vertical wall 24a is smaller than or equal to one sixth of a length L2 of the side wall 24, it is not preferable because the length L1 of the vertical wall 24a is too short and the fin fixing portion 14 may not be closely contacted properly. Meanwhile, if the length L1 of the vertical wall 24a is greater than or equal to one half of a length L2 of the side wall 24, the angle made by the tapered wall 24b and the corner 24c becomes too steep and the fin fixing portion 14 may not be closely contacted properly, which is not preferable either. Therefore, it is more preferable to set the length L1 of the vertical wall 24a to be greater than or equal to one fourth and smaller than or equal to one third of a length L2 of the side wall 24.

It is preferable to form the corner 24c with a radius to be greater than or equal to one sixteenth and smaller than or equal to one third of the width of the fixing groove 23. If the radius of the corner 24c is smaller than or equal to one sixteenth of the width of the fixing groove 23, the angle of the corner 24c becomes too steep and the fin fixing portion 14 may not be closely contacted properly along the shape of the corner 24c. Meanwhile, if a radius of the corner 24c is greater than or equal to one third of the width W2 of the fixing groove 23, the angle of the corner 24c becomes too large and the fixing strength may not be enough, which is not preferable either. Therefore, it is more preferable to form the vertical wall 24a with a radius to be greater than or equal to one eighth and smaller than or equal to one fourth of the width W2 of the fixing groove 23.

The bottom 25 is formed as a flat surface nearly parallel to the upper surface 21 of the support substrate 20, having a ridge 26 at least in one portion which is higher than the bottom 25 and is parallel to the bottom 25.

In this embodiment, the ridge 26 is formed nearly in the central region of the bottom 25. The ridge 26 is formed so that, the height H2 from the fixing groove 23 is greater than or equal to one tenth and smaller than or equal to two thirds of the height of the fixing groove 23, the width W3 of the lower end portion is greater than or equal to one tenth and smaller than or equal to five sixths of the width W2 of the fixing groove 23, the width W4 of the upper end portion is greater than or equal to one eighth and smaller than or equal to four fifths of the width W4 of the width W3 of the lower end portion of the ridge 26, and the width W4 of the upper end portion of the ridge 26 is smaller than or equal to the width W3 of the lower end portion of the ridge 26. Herewith the contact area between the fin fixing portion 14 and the fixing groove 13 can be increased. Further, it is more preferable to set the height H2 of the ridge 26 from the fixing groove 23 to be greater than or equal to one fourth and smaller than or equal to one half of the height of the fixing groove 23, the width W3 of the lower end portion of the ridge 26 to be greater than or equal to one fifth and smaller than or equal to one third of the width W2 of the fixing groove 23, and the width W4 of the ridge 26 to be greater than or equal to one third and smaller than or equal to one half of the width W3 of the ridge 26.

The support substrate 20 is produced, for example, by extruding or cutting one surface of a metal plate (the upper surface 21 in the embodiment) and forming a plurality of fixing groove 23.

In addition, an engaging portion 28 is formed on both ends of the support substrate 20 for engaging an outermost fin bottom 15, which is located at outermost part of the corrugated fin 10, with a jointing portion 13, which is formed contiguously to the outermost fin bottom 15. The engaging portion 28 includes an engaging side wall 28a which extends downward from the upper surface 21 in a vertical direction, and an engaging bottom 28b which is formed contiguously from the engaging side wall 28a and is parallel to the support substrate 20. The width of the engaging portion 28 is determined to be nearly equal to the distance between the outer end of the outermost fin bottom 15 and the external wall of the jointing portion 13.

Further, a clamping portion 29 is formed outside the engaging portion 28. The clamping portion 29 is used for clamping and fixing the outermost fin bottom 15 onto the engaging portion 28 by being crushed, and in this embodiment the clamping portion 29 is formed to be a protrusion along the outer end portion of the engaging bottom 28b of the engaging portion 28. It is preferable that the height H3 of the clamping portion 29 is made lower than the height of the engaging side wall 28a, that is the height H1 of the fixing groove 23, so that, when clamping portion 29 is crushed flatly, the top thereof may not get stuck on the engaging side wall 28a.

Next, a process in which the fin fixing portion 14 is fixed onto the fixing groove 23 will be explained referring to FIGS. 3A to 3C, and FIGS. 1 to 2 as appropriate. As shown in FIG. 3A, the fin fixing portion 14 of the corrugated fin 10 is inserted from the opening of the fixing groove 23 and fit and fixed onto the ridge 26. Then, as shown in FIG. 3B, the fin bottom 11 is pressed toward the ridge 26 of the fixing groove 23 with the tip of a press tool 31 having a concave portion 31a. Thus, the fin bottom 11 is closely contacted along the shape of the ridge 26, and spread widthwise in the bottom 25 of the fixing groove 23 from the ridge 26, and finally closely contacted along the shape of the corner 24c.

Owing to the side wall 24 of the fixing groove 23, having the vertical wall 24a and the tapered wall 24b, when the fin fixing portion 14 is fit and fixed onto the fixing groove 23, the fin fixing portion 14, especially the jointing portion 13, 13 thereof is in close contact with the side wall 24 according to the lateral force between adjacent corrugated fins 20. In addition, the side wall 24 having the corner 24c with a curve, can contact the fin fixing portion 14 closely onto the corner 24c. Thus, as shown in FIG. 3C, the fin fixing portion 14 is closely contacted and fixed along the shape of the fixing groove 23.

At the same time, by fitting the outermost jointing portion 13 and the outermost fin bottom 15 into the engaging portion 28 (see FIG. 1B), and by pressing the clamping portion 29 with a press tool 32 having a flat top toward an engaging bottom 28b (see FIG. 1B), the clamping portion 29 is crushed flatly according to the shape of the press tool 32 and spreads over the outermost fin bottom 15, and presses the outermost fin bottom 15 toward the engaging bottom 28b (see FIG. 1B). Herewith, as shown in FIG. 3C, the outermost fin bottom 15 and the jointing portion 13 are fixed onto the engaging portion 28 (see FIG. 1B).

Thus, the corrugated fin 20 is fixed to the support substrate 10. Meanwhile, it is preferable to make the concave portion 31a of the press tool 31 have a width and depth suitable for contacting the fin bottom 11 according to the shape of the ridge 26, considering the width and height of the lower end portion of the ridge 26 and the thickness of the fin bottom 11.

According to the corrugated-fin type radiator 1 in the embodiment, by contacting the fin fixing portion 14 of the corrugated fin 10 along the shape of the fixing groove 23 of the support substrate 20, the contact area between the corrugated fin 10 and the support substrate 20 can be increased, and the heat conduction effect from the support substrate 20 to the corrugated fin 10 can be improved. As a result, the radiation efficiency of the corrugated-fin type radiator 1 is improved. In addition, the fixing strength of the corrugated fin 10 to the support substrate 20 is improved as well.

While the foregoing has described a corrugated-fin type radiator according to the embodiment, a corrugated-fin type radiator according to the present invention is not limited to the embodiment, and various modifications thereto can be made without departing from the spirit and scope of the invention

Claims

1. A corrugated-fin type radiator, comprising:

corrugated fins that radiate heat; and

a support substrate having a plurality of fixing grooves including side walls and a bottom for fixing a part of the corrugated fins;

wherein the bottom has a ridge on at least a part thereof, which is higher than the bottom and is formed in parallel to the bottom,

and the side walls have vertical walls extending downward from the support substrate in a vertical direction, tapered walls extending from the vertical walls toward the bottom with increase in a distance between the tapered walls, and corners having a curved surface formed contiguously from the tapered walls to the bottom,

and wherein a part of the corrugated fin is fixed along the shape of the side wall and the bottom of the fixing groove.

2. The corrugated-fin type radiator according to claim 1, wherein:

a length of the vertical wall is greater than or equal to one sixth and smaller than or equal to one half of a length of the side wall.

3. The corrugated-fin type radiator according to claim 1, wherein:

a height of the ridge is greater than or equal to one tenth and smaller than or equal to two thirds of a height of the fixing groove, a width of a lower end portion of the ridge is greater than or equal to one tenth and smaller than or equal to five sixths of a width of the fixing groove, a width of a upper end portion of the ridge is greater than or equal to one eighth and smaller than or equal to four fifths of a width of the lower end portion of the ridge, and a width of the upper end portion is smaller than or equal to the width of the lower end portion.

4. The corrugated-fin type radiator according to claim 1, wherein:

a radius of the corner is greater than or equal to one sixteenth and smaller than or equal to one third of a width of the fixing groove.

5. The corrugated-fin type radiator according to claim 3, wherein:

a radius of the corner is greater than or equal to one sixteenth and smaller than or equal to one third of a width of the fixing groove.

6. A method of producing the corrugated-fin type radiator of claim 1, comprising:

a substrate manufacturing step of extruding or cutting the support substrate, forming the plurality of fixing grooves which is formed of, the side wall having the tapered wall and the corner, and of the bottom, and forming the ridge on the bottom;

a fin shaping step of producing a corrugated fin by folding a metal plate to form a plurality of fin bottoms which form a lower end of the corrugated fin and are substantially parallel to the support substrate, a plurality of fin top portions which form an upper end of the corrugated fin and are substantially parallel to the support substrate, and a plurality of jointing portions which joint the fin bottom and the fin top portion and which are substantially perpendicular to the support substrate, so that the fin bottoms and the fin top portions are arranged one after the other, and so that the distance between external walls of the neighboring jointing portions is approximately equal or somewhat smaller than the opening width of the fixing groove; and

a fixing step of fixing the corrugated fin on the support substrate by, inserting the fin fixing portion, which is formed of the fin bottom and a lower end of the jointing portion, into the fixing groove from the opening, fitting the fin fixing portion onto the ridge, and pressing the fin bottom toward the ridge from the gap of the jointing portion using the top of a press tool having a concave portion on top thereof, and deforming the fin fixing portion along the shape of the fixing groove, thereby the corrugated fin being fixed on the support substrate.