JP2013239675A - Cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate positioning of columnar fins where the pitch of the fins is narrowed.SOLUTION: A cooler is formed by housing a fin unit 31 in a base substance formed by joining a first base substance formation member forming a square box shape to a flat plate like second base substance formation member having a square shape in a plane view. The fin unit 31 is formed by forming columnar fins 33 on both surfaces of a flat plate like substrate 32. An apical surface of each fin 33 is joined to an inner surface of the base substance.

Description

  The present invention relates to a cooler that cools a heating element joined to a base by circulating a heat medium in an internal region of the base.

  As a cooler for cooling a heating element such as an electronic component, a cooler in which a flow path is formed inside a base is known. In this type of cooler, it is desired to improve the cooling efficiency with respect to the heating element. In Patent Document 1, the fin-to-fin pitch is narrowed to increase the surface area of the fins. .

  The cooler of patent document 1 opposes the 1st convex board | substrate with which several 1st convex parts were formed in the 1st board | substrate, and the 2nd convex board | substrate in which several 2nd convex parts were formed in the 2nd board | substrate. It is comprised by joining so that. By configuring the cooler in this way, the front end surface of the first convex portion comes into contact with the second convex substrate, and the front end surface of the second convex portion comes into contact with the first convex substrate.

JP 2008-294196 A

  By the way, even if the cooler of patent document 1 can narrow the pitch between fins, the manufacture was not easy. Since the pitch between the fins is narrowed, there are a plurality of first and second convex portions. In this case, if the first convex substrate and the second convex substrate are arranged so that the first convex portion and the second convex portion face each other, it is difficult to align the second convex portion with respect to the first convex portion. In this case, if the front end surface of the first convex substrate and the front end surface of the second convex substrate are disposed at a predetermined location, the first convex substrate and the second convex substrate need to be disposed again.

  The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide a cooler that can facilitate alignment of columnar fins with a narrow pitch. is there.

  In order to solve the above problems, the invention according to claim 1 is a cooler that cools the heating element bonded to the substrate by circulating a heat medium in an internal region of the substrate to which the heating element is bonded. In the internal area, a fin unit in which a plurality of columnar fins are formed at a narrow pitch on both surfaces of the substrate is disposed, and an end surface of the fin is bonded to an inner surface of the base. To do.

  According to this, the fin is formed on both surfaces of the substrate, and the fin formed on both surfaces of the substrate can be handled as one fin unit. For this reason, if the fin unit is positioned, it is not necessary to position the fins individually, and alignment of the columnar fins with a narrow pitch can be facilitated. The “narrow pitch” refers to a pitch between fins in which the shortest separation distance between adjacent fins is 1/6 to 2 times the fin diameter.

Invention of Claim 2 is a cooler of Claim 1, Comprising: The said fin is integrally formed on both surfaces of the said board | substrate.
According to this, both surfaces of the substrate and the fin are integrally formed. Therefore, fins can be easily formed on both surfaces of the substrate.

The invention according to claim 3 is the cooler according to claim 1 or 2, wherein the fin unit is integrally formed.
According to this, the board | substrate thickness is formed thinly compared with the case where the surface in which the fin is not formed in a pair of member in which the fin was formed on one surface of the board | substrate is joined, and a fin unit is formed. Therefore, the fins can be formed thicker as the board thickness is reduced, so that the contact area between the fin unit and the heat medium is increased, and the cooling efficiency for the heating element is improved.

  Invention of Claim 4 is a cooler of Claim 1 or Claim 2, Comprising: The surface in which the fin of the 1st fin unit formation member by which the fin was integrally formed by one surface of the base part is not formed, The gist is that the fin unit is formed by joining a surface of the second fin unit forming member in which the fin is integrally formed on one surface of the base portion to which the fin is not joined.

  According to this, the cooling efficiency with respect to the 1st surface and the cooling efficiency with respect to the 2nd surface can be easily changed by changing the combination of the 1st fin unit formation member and the 2nd fin unit formation member. For example, when the heat generation amount of the heating element bonded to the first surface is larger than the heat generation amount of the heating element bonded to the second surface, the amount of fins formed at the base of the first fin unit forming member May be made larger than the amount of fins formed at the base of the second fin unit forming member.

A fifth aspect of the present invention is the cooler according to any one of the first to fourth aspects, wherein the fin unit is formed by forging.
According to this, fins can be easily formed on both surfaces of the substrate.

  According to the present invention, alignment of columnar fins with a narrow pitch can be facilitated.

The disassembled perspective view which shows the cooler in 1st Embodiment. Sectional drawing which shows the cooler in 1st Embodiment. The perspective view which shows the fin unit in 1st Embodiment. Sectional drawing which shows the cooler in 2nd Embodiment. The disassembled perspective view which shows the fin unit in 2nd Embodiment.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, the cooler 10 is formed by housing a fin unit 31 inside a base body 20 composed of a first base body forming member 21 and a second base body forming member 22. The first base body forming member 21 is formed of side walls 20c erected from four sides of a bottom portion 20b having a rectangular shape in plan view. The side facing the bottom 20b of the first base body forming member 21 is open. The second substrate forming member 22 is a flat plate-like member having a rectangular shape in plan view, and is sized so as to close the opening of the first substrate forming member 21. And the base | substrate 20 is formed by joining the 2nd base | substrate formation member 22 so that the opening part of the 1st base | substrate formation member 21 may be plugged up.

  As shown in FIG. 2, an internal region S in which the heat medium flows is formed inside the base body 20. A supply pipe 23 that supplies a heat medium to the internal region S and a discharge pipe 24 that discharges the heat medium from the internal region S are provided on both side walls 20c erected from the short side of the bottom 20b in the first base member 21. An opening 20a to be fitted is formed. The supply pipe 23 and the discharge pipe 24 are joined to the opening 20a. The surface opposite to the inner region S in the first base body forming member 21 is a first surface 25 to which the power module P as a heating element is joined. Further, the surface opposite to the inner region S in the second base body forming member 22 is a second surface 26 to which the power module P is joined. On the first surface 25, a convex portion 25 a that protrudes toward the internal region S is formed at a substantially center in the short direction of the first base body forming member 21. The convex portions 25 a are formed at regular intervals along the longitudinal direction of the first base body forming member 21 from the supply pipe 23 side toward the discharge pipe 24 side. In addition, a depression is formed at the place where the convex portion 25 a is formed on the first surface 25. In addition, the convex part 25a is formed so that the protrusion amount toward the internal region S does not hinder the flow of the heat medium flowing through the internal region S.

  In the internal region S, a fin unit 31 is disposed. Each fin unit 31 is disposed so as to be positioned between the convex portions 25a, that is, so as to sandwich the convex portion 25a between adjacent fin units 31. Therefore, the convex portion 25 a functions as a positioning portion for the fin unit 31.

Next, the fin unit 31 will be described in detail.
As shown in FIG. 3, the fin unit 31 is configured by forming cylindrical fins 33 on both surfaces of a flat substrate 32. The same number of fins 33 having the same shape are formed on both surfaces of the substrate 32. The diameter of the fin 33 is set to 2.1 mm. The diameter of the fin 33 can be set within a range of 1 mm to 3 mm.

  Further, the fins 33 are arranged alternately. By arranging the fins 33 in a staggered manner, more fins 33 can be arranged in the same region than in the case where the fins 33 having the same shape are arranged in the same region at regular intervals. That is, the contact area between the heat medium and the fins 33 is increased.

  The pitch between adjacent fins 33 is narrowed. The “narrow pitch” refers to a pitch between fins in which the shortest separation distance between adjacent fins 33 is 1/6 to 2 times the diameter of the fin 33. In the present embodiment, the shortest separation distance between the alternately adjacent fins 33 is set to 0.9 mm. The shortest separation distance between adjacent fins 33 can be set between 0.5 mm and 2 mm.

  As shown in FIG. 2, both surfaces of the substrate 32 of the fin unit 31 face the first surface 25 and the second surface 26 in a state where the fin unit 31 is disposed in the internal region S. Therefore, it can be understood that the fins 33 are extended from both surfaces of the substrate 32 toward the first surface 25 and the second surface 26. Further, the fin unit 31 is disposed corresponding to the power module P joined to the base body 20. That is, the wall portions (the first substrate forming member 21 and the second substrate forming member 22) of the base 20 are arranged so that heat exchange with the power module P is appropriately performed when the heat medium flows through the internal region S. The power module P and the fin unit 31 are disposed so as to face each other.

  Further, assuming that the end of the fin 33 on the side of the substrate 32 is the base end and the end on the opposite side of the substrate 32 is the front end, the front end surface is bonded to the inner surface of the base body 20. More specifically, the entire end surface of the fin 33 formed on the first base forming member 21 side in the fin unit 31 is bonded to the inner surface of the first base forming member 21. Similarly, the entire end surface of the fin 33 formed on the second substrate forming member 22 side in the fin unit 31 is bonded to the inner surface of the second substrate forming member 22. Each fin 33 is formed so that the cross-sectional area in the direction orthogonal to the flow direction of the heat medium is substantially the same from the base end to the tip end. And the flow path area between each fin 33 is substantially the same.

  The fin unit 31 is configured by integrally forming the substrate 32 and the fins 33. Specifically, the fin unit 31 is formed by hot forging an aluminum plate or a copper plate with a forging die formed in accordance with the shape of the fin unit 31. Therefore, the plate thickness t1 of the substrate 32 of the present embodiment is thinner than a fin unit formed by joining the surfaces on which fins are not formed in a pair of fin unit forming members in which fins are formed on one surface of the substrate. It has become. Accordingly, the length of the fin 33 in the extending direction is increased by the amount that the plate thickness t1 is reduced. That is, the contact area between the heat medium flowing through the internal region S and the fins 33 is increased.

  In the cooler 10 of the present embodiment, a brazing material is applied to the surface on the inner region S side of the first substrate forming member 21 and the second substrate forming member 22, and the tip surfaces of the fins 33 in the fin unit 31 are the first substrate. The forming member 21 and the second substrate forming member 22 are formed by being collectively brazed while being in contact with the brazing material applied. At the time of brazing, the base body 20 is pressurized and brazed. For this reason, even if the brazing material is melted, the tip surfaces of the fins 33 are not separated from the inner surface of the substrate 20, and the bonding is performed in a state where the inner surfaces of the substrate 20 and the tip surfaces of the fins 33 are in close contact.

Next, the effect | action of the cooler 10 in this embodiment is demonstrated.
The cooler 10 in the present embodiment is suitably used for cooling a power device (heating element) such as an IGBT (Insulated Gate Bipolar Transistor) used in a power conversion device mounted on an electric vehicle, a hybrid vehicle, a train, or the like. It is done.

  When the power module P generates heat by being driven, the power module P is cooled by exchanging heat with the heat medium flowing through the internal region S. At this time, since the power module P is bonded to both sides of the first surface 25 and the second surface 26 of the base body 20, the cooler 10 is heated from both sides of the first surface 25 and the second surface 26.

  Since the fin unit 31 of the present embodiment forms the fins 33 on both surfaces of the substrate 32, the power module P joined to the first surface 25 is appropriately heat-exchanged by the fins 33 on the first surface 25 side. Then, the power module P joined to the second surface 26 is appropriately heat-exchanged by the fins 33 on the second surface 26 side.

  Particularly, by forming a plurality of columnar fins 33 as the shape of the fins 33, the surface area is increased compared to the case of forming straight fins on both surfaces of the substrate 32. For this reason, heat exchange between the heat medium and the fin unit 31 is promoted.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) Cylindrical fins 33 are formed on both surfaces of the substrate 32 disposed so as to face the first surface 25 and the second surface 26. Therefore, by positioning the fin unit 31 in the internal region S, the positioning of all the fins 33 is performed. Therefore, if the fin unit 31 is positioned, it is not necessary to position the fins 33 individually, and the alignment of the columnar fins 33 with a narrow pitch can be facilitated.

  (2) Cylindrical fins 33 extending toward the first surface 25 and the second surface 26 are formed on both surfaces of the substrate 32 disposed so as to face the first surface 25 and the second surface 26. ing. For this reason, the power module P joined to the first surface 25 is appropriately heat-exchanged by the fins 33 formed on the first surface 25 side, and the power module P joined to the second surface 26 has the second surface Heat is appropriately exchanged by the fins 33 formed on the 26th side. Therefore, the power module P joined to the first surface 25 and the second surface 26 of the base body 20 can be efficiently cooled.

  (3) As the shape of the fins 33, columnar fins 33 are formed on the substrate 32. For this reason, the surface area is increased compared with the case where straight fins are formed on both surfaces of the substrate 32. Therefore, the cooling efficiency for the power module P is improved.

  (4) Further, by forming the columnar fins 33 on the substrate 32, the tip surfaces of the fins 33 and the substrate 20 can be brought into surface contact. Therefore, the contact area between the base 20 and the fin unit 31 is increased. For this reason, the heat generated by the power module P is easily conducted to the fin unit 31 and the cooling efficiency for the power module P is improved.

(5) Further, by forming the columnar fins 33 on the substrate 32, turbulent flow of the heat medium flowing through the internal region S is likely to occur, and the cooling efficiency for the power module P is improved.
(6) In addition, the base 20 is supported by the fin unit 31 by the surface contact between the base 20 and the tip surfaces of the fins 33, and the strength of the base 20 in the thickness direction is improved.

  (7) Fins 33 are integrally formed on both surfaces of the substrate 32. For this reason, it is easy to form the fins 33 on the substrate 32. Further, the bonding failure between the substrate 32 and the fin 33 is eliminated, and the life of the cooler 10 is extended.

  (8) The fin unit 31 is integrally formed. For this reason, the plate thickness t1 is a fin unit formed by joining the surfaces where fins are not formed in a pair of fin unit forming members in which the fins 33 are formed on one surface of the substrate having the same plate thickness t1 as the substrate 32. It is thinner than Therefore, the length of the fin 33 in the extending direction can be increased, and the cooling efficiency for the power module P is improved. Moreover, since the plate | board thickness becomes thin, the cooler 10 whole can be made thin.

  (9) The fins 33 are formed alternately. For this reason, many fins 33 can be arrange | positioned in the same area | region compared with the case where the fin 33 of the same shape is arranged in the same area | region. Therefore, the contact area between the heat medium and the fins 33 is increased, and the cooling efficiency for the power module P is improved.

  (10) The length of each fin 33 in the extending direction is shorter than when straight fins are formed in the same region. For this reason, the expansion / contraction of the fin 33 when the cooler 10 is heated / cooled during brazing is less than that of the straight fin. Therefore, the amount of deformation of the fin 33 during brazing is small, and the deformation of the first surface 25 and the second surface 26 is suppressed as the fin 33 is deformed. For this reason, it is suppressed that an unevenness | corrugation is formed in the 1st surface 25 and the 2nd surface 26, and the joining reliability of the base | substrate 20 and the power module P is improved.

  (11) The entire front end surface of the fin 33 formed on the substrate 32 is bonded to the inner surface of the base body 20. For this reason, the pressing force applied to the fins 33 is dispersed when the base body 20 is pressed when the cooler 10 is brazed. For this reason, the fins 33 are not easily damaged.

(12) By forming the fins 33 alternately, turbulent flow of the heat medium flowing through the internal region S is likely to occur, and the cooling efficiency for the power module P is improved.
(13) The fin unit 31 is formed by forging. Therefore, the fins 33 can be easily formed on both surfaces of the substrate 32.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In the embodiments described below, the same components as those already described are denoted by the same reference numerals, and redundant description thereof is omitted or simplified.

As shown in FIG. 4, the cooler 40 of the present embodiment is configured by disposing a fin unit 51 in the internal region S of the base body 20, as in the first embodiment.
As shown in FIG. 5, the fin unit 51 is the same as the first fin unit forming member 53 and the surface of the first fin unit forming member 53 in which the fins 33 are formed on one surface of the base 52 and the fin 33 is not formed. The second fin unit forming member 54 having the structure is formed by joining the surfaces on which the fins 33 are not formed. In the present embodiment, the substrate 55 is formed by the base 52 of the first fin unit forming member 53 and the base 52 of the second fin unit forming member 54. The fins 33 are integrally formed on one surface of the base 52. And since both surfaces of the board | substrate 55 become the surface in which the fin 33 was formed in the base 52, the fin 33 is integrally molded by the both surfaces of the board | substrate 55. FIG.

  As shown in FIG. 4, the plate thickness t2 of the substrate 55 of the present embodiment is twice t1 when the thickness of the base 52 is the same as the thickness of the substrate 32 of the first embodiment. That is, if the inner region S of the base 20 has the same dimensions as the inner region S of the base 20 of the first embodiment, the length of each fin 33 in the extending direction is shortened by t1 / 2.

Therefore, according to the above embodiment, the same effects as the effects (1) to (6) and (9) to (13) of the first embodiment can be obtained.
In addition, you may change embodiment as follows.

In each embodiment, the shape of the fin 33 may be a polygonal columnar fin 33 such as a triangular columnar fin 33 or a quadrangular columnar fin 33.
In each embodiment, the number of fins 33 may be increased or decreased.

In each embodiment, the number of fins 33 formed on the first surface 25 side may be different from the number of fins 33 formed on the second surface 26 side.
In each embodiment, a capacitor, a transistor, or the like may be employed as the heating element.

  (Circle) in each embodiment, the board | substrate 32 and the fin 33 do not need to be integrally molded. For example, the fins 33 may be formed on both surfaces of the substrate 32 by brazing the fins 33 on both surfaces of the substrate 32. Similarly, the base 52 and the fins 33 may not be integrally formed. For example, the fins 33 may be brazed to one surface of the base 52.

In each embodiment, a single fin unit 31 may be disposed in the inner region S.
In each embodiment, the fins 33 formed on the substrates 32 and 55 may be arranged at regular intervals.

In the first embodiment, the substrate 32 and the fins 33 may be integrally formed by cold forging or molten metal forging.
In each embodiment, the power module P may be joined to either the first surface 25 or the second surface 26.

  In the second embodiment, the first fin unit forming member 53 and the second fin unit forming member 54 may be configured differently. By changing the combination of the 1st fin unit formation member 53 and the 2nd fin unit formation member 54, the cooling efficiency with respect to the 1st surface 25 and the cooling efficiency with respect to the 2nd surface 26 can be changed easily. For example, when the heat generation amount of the power module P bonded to the first surface 25 is larger than the heat generation amount of the power module P bonded to the second surface 26, the base 52 of the first fin unit forming member 53 The amount of the fins 33 formed may be larger than the amount of the fins 33 formed on the base 52 of the second fin unit forming member 54.

In each embodiment, the fins 33 may be formed so that the cross-sectional area in the direction orthogonal to the flow direction of the heat medium is the same from the base end to the tip.
(Circle) in each embodiment, the convex part 25a which functions as a positioning part may be formed in the 2nd surface 26. FIG. Further, it may be formed on both the first surface 25 and the second surface 26.

In each embodiment, the shortest separation distance between adjacent fins 33 may be longer or shorter as long as it is within a range of 1/6 to 2 times the diameter of fin 33.
In each embodiment, the fin pitch between some of the fins 33 among all the fins 33 may not be a narrow pitch.

  DESCRIPTION OF SYMBOLS 10,40 ... Cooler, 20 ... Base | substrate, 25 ... 1st surface, 26 ... 2nd surface, 31, 51 ... Fin unit, 32, 55 ... Board | substrate, 33 ... Fin, 52 ... Base part, 53 ... 1st fin unit Forming member, 54 ... second fin unit forming member.

Claims (5)

A cooler that cools the heating element bonded to the substrate by circulating a heat medium in an inner region of the substrate to which the heating element is bonded;
In the internal region, a fin unit in which a plurality of columnar fins are formed at a narrow pitch on both surfaces of a substrate is disposed, and an end surface of the fin is joined to an inner surface of the base body. vessel.   The cooler according to claim 1, wherein the fin is integrally formed on both surfaces of the substrate.   The cooler according to claim 1 or 2, wherein the fin unit is integrally formed.   The surface of the first fin unit forming member in which the fin is integrally formed on one surface of the base and the surface of the second fin unit forming member in which the fin is integrally formed on the one surface of the base are not joined. The fin unit is formed by joining together. The cooler according to claim 1, wherein the fin unit is formed.   The cooler according to any one of claims 1 to 4, wherein the fin unit is formed by forging.