JP4583082B2 - Boiling cooler - Google Patents

Description

  The present invention relates to a boiling cooler and relates to a cooler for forcibly air-cooling a heat generating portion with a cooling fluid such as air flowing by a fan or the like.

Conventionally, various methods have been used to cool a large-capacity heating element. For example, a boiling cooling system as shown in FIG. 7 is mainly used in order to process a large capacity heat generation such as an IGBT (Insulated Gate Bipolar Transistor) used in power electronics.
In this boiling cooling system, there is a substrate part 70 to which a heat generating element is attached below, a condensing part 71 is provided above the substrate part 70, and a header part 72 is provided above the condensing part. An evaporation unit 73 is provided inside the substrate unit at a portion of the substrate unit 70 corresponding to the bottom surface of the condensing unit 71. Normally, perfluorocarbon (hereinafter referred to as PFC) is sealed in the evaporation section as the working refrigerant. Reference numeral 74 denotes a PFC injection sealing portion.

Perfluorocarbon is an odorless and harmless refrigerant and has an ozone depletion coefficient of zero, so there is no restriction on its use. FIG. 2 shows the characteristics of C ₆ F ₁₄ as an example of PFC. In the figure, the horizontal axis represents temperature, and the vertical axis represents saturated vapor pressure. As can be seen from this, it can be used as a refrigerant working fluid from about -20 ° C. to about 80 ° C. and is widely used as a refrigerant working fluid for a boiling cooler.
The greatest advantage of the boiling cooling system using this hydraulic fluid is the high performance of heat dissipation performance, and it is often used especially for power inverter system semiconductor element cooling applications for railway vehicles.

  As an example, there is a cooler described in Patent Document 1. This part is a container part (evaporation part) that encloses the above-mentioned PFC called an evaporation part, and an aluminum fin inside which PFC vapor rises by receiving heat from a heating element called a condensation part. And the container part communicate with each other by a hole arranged in the evaporation part) and an external aluminum fin as a heat dissipation means by a cooling method with an external fan or the like (this is an evaporation part and a container part) No communication). Further, the uppermost part of the upper container part is connected by a plate member made of aluminum, also called a header. By attaching this aluminum plate material, it has become unnecessary to provide a large liquid reservoir in this portion.

However, as described above, the boiling-type cooler of Patent Document 1 has a large number of constituent members, and a large portion that encloses the PFC is indispensable to be kept airtight at the vapor level. It is required to clear an airtight test of 10 ⁻⁷ acc / sec. Therefore, it is important to reduce the number of joints involved in airtightness as much as possible. However, it has been difficult to reduce the number of joints without degrading the heat dissipation performance and without increasing the size.
JP 2002-134670 A

  An object of the present invention is to provide a boiling cooler with improved cooling performance, and to provide a boiling cooler with improved reliability without enlarging conventional dimensions.

The above object of the present invention has been achieved by the following means.
(1) an evaporation section formed on a substrate for mounting a heating element on the lower surface, provided on the upper surface of the evaporation portion communicates with the evaporator unit, erected a plurality of container member having a fin therein at predetermined intervals And a condensing part in which corrugated fins are provided in the entire width between the container members outside the container members, and the substrate is formed on a lower plate on which a refrigerant flow path is formed, and an upper surface of the lower plate. Provided with a vertical partition frame that forms an evaporation rising space of the refrigerant from the refrigerant flow path, and an upper plate on which a plurality of horizontal partition frames provided on the side of the vertical partition frame are formed, A boiling cooler characterized in that a notch is provided in the vertical partition frame.
(2) the refrigerant between the fin top end provided inside the container member and the container member is characterized in that spaced a predetermined gap height can move in the horizontal direction (1) boiling cooling according vessel.
(3) The refrigerant in the refrigerant evaporating section flows through a flow path having a groove structure formed by a plurality of three-dimensional walls provided at parallel predetermined heights and provided with intermittent cutouts (1) or (2) The boiling cooler as described.
(4) boiling cooler according to any one of the fine groove on a bottom surface of the refrigerant flow path formed in the lower plate is characterized by being facilities (1) or (2).
(5) surface of the lower plate is characterized in that etching is facilities (1) to the boiling cooler of any one of (4).

According to the present invention, it is possible to further improve the reliability without deteriorating the performance of the boiling cooler used for conventional vehicles. Also, by eliminating the joining of the header part, the ease of assembly is improved, and the connection of all the joining parts is completed by one brazing operation, and then the product is completed by degassing and sealing the PFC. As a result, the manufacturing cost can be greatly reduced.
As described above, the present invention makes it possible to provide a radiator capable of reducing the size and greatly improving the manufacturing cost while making the heat dissipation performance equal to or higher than that of the conventional product.

The specific contents of the present invention will be described an embodiment based.
FIG. 1 is an overall view of the product of the present invention. As shown in FIG. 1, component roughly comprises a substrate 2 having evaporation portion 1 which is disposed in correspondence with the bottom of the condensing unit 3, the condenser portion 3 mounted on the evaporating section 1, consisting of city . The condensing unit 3 is assembled by alternately arranging a plurality of container members 4 and corrugated fins 5 standing at predetermined intervals.
The condensing unit 3 is shown in a perspective view in FIG. The container member 4 has fins 60 (see FIG. 6) inside , and the upper surface and both side portions of the container member 4 are sealed with a substantially U-shaped side frame. The upper surface and the bottom surface of the corrugated fin 5 are closed by the upper surface plate 6a and the lower surface plate 6b, respectively. Thus, the condensing part 3 has the container member 4 standingly arranged by the predetermined space | interval. Although not shown in the drawing, a heating element is attached to the back surface (lower surface) of the substrate and has a PFC injection sealing portion as in the conventional case.
Thus, in the embodiment of the present invention, there is no header portion that allows communication between the uppermost portions of the condensing portion. Instead of the header function for communicating between the uppermost parts of the condensing part, a split member made of an aluminum extrusion molded product inside the evaporation part is provided with a notch in the joint part to communicate therewith.

FIG. 4 is an enlarged perspective view of the substrate 2 from which the condenser 3 has been removed from the cooler of FIG. As shown in the drawings, the evaporation section 1 is composed of a lower plate 8 having a refrigerant flow path and an upper plate 9 combined therewith. In this embodiment, the upper plate 9 is an upper plate left plate 9a, upper plate 9a. The right plate 9b is joined. The lower plate 8 has Mizotai 10 to form the channel 11, at regular intervals, are arrayed in parallel to the lower plate 8. The surface of the lower plate 8 may be increased in surface area by etching.
The upper plate 9 is formed with a vertical partition frame 9c and a horizontal partition frame 9d. A hole formed between the vertical partition frame 9c and the horizontal partition frame 9d is a space where the refrigerant evaporates from the refrigerant flow path, and the container member 4 evaporated from the flow path 11 through this portion. The refrigerant rises into the interior. A notch 12 is provided in the vertical partition frame 9 c of the upper plate 9 .

Since the boiling cooler used for vehicles has a large number of IGBTs (Insulated Gate Bipolar Transistors) used for inverters and the like to be mounted thereon, the substrate 2 needs to have a size of about 1 m square. The aluminum material usually used as the member has a vertically divided structure, and although not limited to this, an aluminum member manufactured by extrusion in which the flat part is usually divided into right and left is also used. A method of joining by means of brazing is used. This is as described above. In this case, in the present invention, as shown in FIG. 4, the frame portion of the evaporation portion 1 composed of the lower plate 8 and the upper plate 9 is cut out at the center portion of both members to provide the notch portion 12 and the left and right evaporations are provided in this portion. Communicate the space.
As shown in FIG. 4, at least one notch 12 is provided, but two or more notches 12 may be provided so that the evaporation rising spaces of the left and right plates are continuous.
In the present invention, the lower part of the container member 4 of the condensing unit 3 and the horizontal partition frame 9d of the evaporating unit are configured to be orthogonal to each other.

Further, a preferred example of the lower plate 8 serving as the refrigerant flow path is enlarged and shown as a perspective view from above in FIG. As shown in the drawing, the groove structure wall 10 is preferably provided with notches 13 periodically.
The ratio of the width (length) between the groove structure wall 10 and the notch 13 is not particularly limited, but a ratio of 3: 1 to 3: 2, particularly 2: 1 is good. As an effect of the notch, if the extruded material is not used, the lateral refrigerant (PFC liquid) cannot be communicated and the liquid flow is hindered. On the other hand, since this product repeats evaporation and condensation inside the PFC liquid, a certain pressure resistance is required. As a result of comprehensively examining these, the ratio of the notches in the base portion of the evaporation portion is good. This ratio is determined by the relationship between the straight advanceability of the PFC liquid in the longitudinal direction and the movement in the lateral direction. The bottom surface of the coolant channel 11 may further deeper cut in narrower than provided slot. The reason for providing this is to provide an action of holding the necessary refrigerant in the flow path even when the cooler is inclined due to capillary action.

Although not shown in the drawings, in the present invention, in order to enhance the distribution effect of the evaporative refrigerant, the width of the horizontal partition frame 9d in the upper plate 9 is made narrower toward the end portion away from the center. It is preferable that the space (refrigerant evaporation space) formed by is expanded as the distance from the vertical partition frame 9c increases in the horizontal direction.
That is, a pattern is provided in which the joining surface between the evaporation part and the condensing part has a larger evaporation rising space at the end part and a smaller part at the central part. The effect of this is that for the size of the flat part of the evaporation part, the condensation part is attached to the outside, and due to the influence of the allowable pressure loss of the external aluminum fins, The size dimension is smaller than the surface. For this reason, the closer to the end of the evaporation section, the larger the notch, and the liquid can circulate around it, improving the liquid flow as a whole.
By doing in this way, the header for communication of the condensation part uppermost part can be made unnecessary. As an effect, a portion for connecting the header portion and the uppermost surface portion of the condensing portion becomes unnecessary, and the risk of imperfect airtightness is greatly reduced. Further, since the header portion is eliminated, the uppermost portion of the condensing portion becomes a flat surface, and the height dimension can be reduced.

Next, in the present invention, as shown in FIG. 1, the container member 4 in which the corrugated fins 5 used in the condensing unit 3 are sandwiched on both sides is formed with aluminum fins inside as shown in FIG. It has 60 (offset fin) . FIG. 6 shows a state in which the container member is partially cut away. It is preferable that the fin 60 is not extended to the uppermost end, and preferably a space 61 having a height of 5 mm to 10 mm is provided, and the lid is placed on the upper portion as it is, and then sealed and joined. The function of this part is that the vapor of the PFC in the evaporation part rises, and the vapor condenses at the uppermost part to return to the liquid state. Furthermore, the PFC that has returned to the liquid state returns to the lower evaporation section through the same flow path. Therefore, the space for returning from the vapor to the liquid is important. Therefore, according to this embodiment, the length of the fin 60 itself is shortened, and the recirculation of the refrigerant liquid is promoted more than the deterioration of the thermal characteristics of the condensing part, and the heat transport characteristics can be improved more than before.

In FIG. 6 , the internal fin 60 is inserted into a structure in which an aluminum fin called an offset fin is sandwiched between aluminum plates on both sides (this is called a container member). Inside the container member, the steam that has risen from the lower evaporation section rises as if it is sewn between the fins 60 . In this process, heat is exchanged with the external corrugated fin 5 to dissipate heat. Those prior extends to the top of the inside of the fin inside the container member, the steam communicates by only the header portion provided thereon has been taken.
However, the interior fins 60, called offset fins, and in structurally intricate structure, the movement of the plane direction vapor has a hard structure. That is, in the communication of the header portion only, it is difficult to from turning uniform vapor in individual the container member. An important function of the header portion, since part inside of the fin 60 is not, PFC vapor in this section is returned to the PFC liquid, it goes back to the evaporator portion through the individual containers member.

  For this reason, the performance of the conventional cooler is as follows. The steam efficiently rises from the evaporation section to the top of the condensing section, condenses quickly at the header section, and the PFC liquid is supplied to the evaporation section in the PFC liquid state. It depends on the succession of the return sequence.

On the other hand, in the present invention shown in the above embodiment, a method of providing a gap of 5 mm to 10 mm at the uppermost portion for each individual container member and promoting the liquefaction of steam at this portion is adopted. As a result, even if the fin 60 inside the container member is shortened by 5 mm to 10 mm at the top, the liquefaction of the steam can be promoted in the conventional header portion, and conversely the heat dissipation performance is improved. . The reason for the narrow header part in promoting hard prior art liquefaction of unless the vapor aggregation progress of the steam width, in the above embodiment the liquefaction of the vapor is accelerated to each individual container member, which internal The heat transfer area reduction effect by shortening the fins 60 may be exceeded.

  In addition, the conventional header section must be installed last, and it is difficult to connect by brazing in consideration of strength. Therefore, only this connection point must be welded. However, in the present invention, since all the joints can be brazed, all the members are connected by one brazing operation, and then the PFC is deaerated and sealed to complete the product. An efficient manufacturing process is now possible.

The boiling cooler of the present invention can be assembled by brazing and joining each member clad with a brazing material. For example the interior of the fin 60 of the container member 4, the brazing material has been clad, joined with both sides of the plate of the container member 4. Further, the bottom end face of the condensing unit 3 is brazed onto the substrate 2.
As described above, according to the present invention, it is possible to delete the header portion without causing performance deterioration by adopting a method for improving the flow of the PFC liquid between the evaporation portion and the condensation portion. As a result, the number of connection points can be reduced, the reliability of hermetic retention is improved, and the height dimension of the boiling cooler can be reduced.

It is a perspective view of an example of the boiling cooler of this invention. It is a saturated evaporation pressure curve of PFC. It is a perspective view which shows one preferable embodiment of the condensation part of the boiling cooler of this invention. It is a perspective view which shows one preferable embodiment of the evaporation part of the boiling cooler of this invention. It is a perspective view from the top which shows one preferable embodiment of the lower surface part of the evaporation part of the boiling cooler of this invention. It is a perspective view which notches some container members used for this invention, and shows an internal state. It is a perspective view of the typical example of the conventional boiling cooler.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Evaporating part 2 Substrate 3 Condensing part 4 Container member 5 Corrugated fin 6a Upper surface board 6b Lower surface board 8 Lower board 9 Upper board 9a Upper board left board 9b Upper board right board 9c Vertical partition frame 9d Horizontal partition frame 10 Groove structure wall 11 Refrigerant flow path 12 Notch 13 Notch

Claims (5)

An evaporation section formed on a substrate on which a heating element is attached to the lower surface;
Provided on the upper surface of the evaporation portion communicates with the evaporator unit, with erected a plurality of container member having fins at predetermined intervals therein, corrugated across the width between the outside the container member of the respective container member Consists of a condensing part with fins,
The substrate is provided with a lower plate on which a refrigerant flow path is formed, a vertical partition frame provided on an upper surface of the lower plate, and forming a space where the refrigerant evaporates from the refrigerant flow path, and a side of the vertical partition frame It is composed of an upper plate on which a plurality of horizontal partition frames provided in the part are formed,
A boiling cooler characterized in that a notch is provided in the vertical partition frame. Boiling cooler according to claim 1, wherein the refrigerant has a predetermined gap height can move in the horizontal direction between the container member and the fin top end provided inside of the container member.   The refrigerant of the refrigerant evaporating section flows through a flow path having a groove structure formed by a plurality of three-dimensional walls provided at parallel predetermined heights and intermittently provided with cutouts. Boiling cooler. Boiling cooler according to any one of claims 1 or claim 2 bottom fine grooving of the refrigerant flow path formed in the lower plate is characterized by being facilities. Boiling cooler according to any one of claims 1 to 4 the surface of the lower plate, characterized in that the etching is facilities.