JP5827559B2 - Cooler - Google Patents

Description

  The present invention relates to a heat pipe type cooler, and relates to a structural improvement of a heat receiving portion.

When water is used as a refrigerant in an aluminum cooler, hydrogen is generated by a chemical reaction and stays in a sealed container, so that the cooling performance deteriorates. For this reason, alternative chlorofluorocarbon is used as a refrigerant, but it has an effect on ozone destruction and global warming. Accordingly, there is a strong demand to use water that does not affect ozone destruction and global warming as a refrigerant.
As a cooler using water as a refrigerant, a single pipe heat pipe is generally used, but there is also a heat pipe unit type cooler as described in Patent Document 1. The heat pipe has a simple structure, is easy to make, and has good thermal efficiency. However, since it does not reach the performance of an aluminum cooler using an alternative chlorofluorocarbon, it is desired to improve its performance.

As what improved the performance of this heat pipe type cooler, there are some which are shown in patent documents 2-4, for example.
In the cooler described in Patent Document 2, a plurality of protrusions that promote nucleate boiling are provided at equal intervals in the circumferential direction on the inner surface of the heat absorbing portion (heat receiving portion) of the heat pipe.
In the cooler described in Patent Document 3, an inner fin that promotes nucleate boiling is fitted to the inner surface of the heat absorbing portion of the heat pipe. As the inner fins, those having a cross-sectional shape extending radially from the radial center of the heat pipe are illustrated.
In the cooler described in Patent Document 4, a plurality of flat plate heat radiation promoting fins are erected in parallel on the inner bottom portion of the heat receiving portion.

JP 2004-125381 A Japanese Utility Model Publication No. 61-161554 Japanese Utility Model Publication No. 61-161560 International Publication No. 2010/058520

  The coolers described in Patent Documents 2 to 4 are said to be able to increase the heat transfer efficiency of the heat receiving part by increasing the contact area with the refrigerant by the protrusions or fins, There is a need for further improvement in cooling performance.

  This invention is made | formed in view of the said situation, and aims at improving the heat transfer efficiency of a heat receiving part, and improving a cooling performance.

In the coolers described in Patent Documents 2 and 3, since the protruding portions and the inner fins are joined by fitting or the like, contact thermal resistance is generated. Further, in the cooler described in Patent Document 4, since the fin height is lower than the liquid level, the enlargement of the surface area is not utilized to the maximum extent.
In order to solve these problems, the present invention employs the following solutions.

That is, in the cooler of the present invention, a plurality of pipes extending in the vertical direction are arranged side by side in the length direction of the tank on the upper side of the tank that is disposed sideways and closed at both ends . The upper end portion is closed, the lower end portion of the pipe is in communication with the tank, and a plate-like rib along the vertical direction is formed along the length direction on the surface of the concave arc wall on the inner bottom surface of the tank. Standing up, the refrigerant is sealed so as to form a liquid level below the upper end of the plate-like rib, the outer bottom surface of the tank is a heat receiving surface, and the tank has its peripheral wall and the plate The ribs are integrally formed.

This cooler is used by embedding an outer bottom surface of a tank in a block or the like and attaching a semiconductor element through the block. The heat of the semiconductor element is transmitted from the outer bottom surface of the tank to the internal refrigerant and heats the refrigerant. The refrigerant boils by heating, the vapor rises into each pipe via the upper space of the tank, condenses by dissipating heat from these pipes, and the condensate descends inside the pipe again to the tank. Returned.
In this case, the plate-like ribs erected in the tank can increase the contact area with the refrigerant and promote heat transfer to the refrigerant. Further, since a corner is formed between the lower end surface of the plate-like rib and the inner peripheral surface of the tank, heat concentrates on the corner, and the boiling nuclei are easily generated due to the concentration of the heat. Therefore, nucleate boiling occurs around this corner. Since this plate-like rib is disposed so that its upper end protrudes upward from the liquid level of the refrigerant, a temperature gradient is generated upward from this corner, and the temperature is highest at the corner. For this reason, the state where the nucleate boiling generated in the corner portion is concentrated in the corner portion is continued without spreading in the surface direction of the tank or the plate-like rib.
Moreover, the peripheral wall of the tank and the plate-like rib are integrally formed, and heat transfer between them can be performed smoothly.

In the cooler of the present invention, a plurality of the plate-like ribs may be provided in parallel with a space between each other.
Since corners are formed between the lower end of each plate-like rib and the inner peripheral surface of the tank, these corners become the core of boiling and can cause nucleate boiling at multiple locations, improving the heat transfer efficiency. It can be further increased.

In the cooler of the present invention, the tank and the plate-like rib may be made of copper or a copper alloy.
Water can be used as a refrigerant, and the influence on the environment can be reduced. Moreover, since the heat transfer efficiency is high due to local nucleate boiling, high cooling performance can be exhibited even when water is used.

  According to the cooler of the present invention, since the plate-like rib protrudes upward from the liquid surface, the contact area with the refrigerant is large, and the peripheral wall of the tank and the plate-like rib are integrally molded, The heat transfer can be performed smoothly, the heat transfer efficiency can be improved, and the cooling performance can be improved.

It is a whole perspective view showing one embodiment of a cooler of the present invention. It is sectional drawing which shows the internal structure of the tank in 1st Embodiment of this invention used for the cooler of FIG. It is sectional drawing similar to FIG. 2 which shows the internal structure of the tank in 2nd Embodiment of this invention. It is sectional drawing similar to FIG. 2 which shows the internal structure of the tank in 3rd Embodiment of this invention.

Hereinafter, embodiments of the cooler of the present invention will be described.
FIG. 1 shows the overall structure of a cooler to which the present invention is applied. The cooler 1 includes a horizontally disposed tank 2, a plurality of pipes 3 erected vertically on the upper side of the tank 2, a base block 4 in which an outer bottom surface of the tank 2 is embedded, and a pipe 3 A plurality of fins 5 provided at the upper end of the base block 4 are provided, and the semiconductor element 6 is fixed to the surface of the base block 4 opposite to the mounting portion of the tank 2.

Both ends of the tank 2 are closed, and the lower end of each pipe 3 is fixed to the upper wall. These pipes 3 are closed at the upper end, but the lower end is opened and the wall of the tank 2 is fixed in a penetrating state so that the inside of the tank 2 and the inside of the pipe 3 are connected to each other. Has been. In the example of the first embodiment of the present invention shown in FIG. 2, a pipe is inserted inside the through hole of the tank 2 and joined by brazing. Further, these pipes 3 are erected vertically so as to be orthogonal to the tank 2, so that they are arranged in a row in the length direction of the tank 2.
The fins 5 are formed in a thin plate shape, and a plurality of fins 5 are stacked with a slight gap therebetween, and attached to the upper end of each pipe 3 in a skewered state.

In the tank 2, vertical plate-like ribs 8 are provided along the length direction of the tank 2 so as to divide the internal space into two left and right spaces. The plate-like rib 8 has its upper end and lower end fixed to the inner peripheral surface of the tank 2, and the two spaces partitioned by the plate-like rib 8 are pipes connected to the tank 2. The three openings 3a communicate with each other. In this case, the tank 2 is manufactured by extrusion molding or continuous casting, and the peripheral wall of the tank 2 and the plate-like rib 8 are integrally formed.
And water is enclosed as a refrigerant to the middle of the height direction so that the upper part of this plate-like rib 8 protrudes from the liquid level. Reference symbol L indicates the liquid level of the refrigerant.
The base block 4 is embedded so as to cover more than half of the lower side of the tank 2. In the illustrated example, the back surface is the semiconductor mounting surface 9, and the outer bottom surface of the tank 2 embedded in the base block 4 is the heat receiving surface. S.
The tank 2 and each pipe 3 are made of copper or a copper alloy, and the base block 4 is made of aluminum or an aluminum alloy. In FIG. 1, reference numeral 10 indicates a refrigerant injection pipe connected to one end of the tank 2.

  The cooler 1 configured as described above is used with the semiconductor element 6 fixed to the semiconductor mounting surface 9 of the base block 4. The heat of the semiconductor element 6 is transferred from the heat receiving surface S on the outer bottom surface of the tank 2 to the internal refrigerant, and when the semiconductor element 6 reaches a high temperature, the heat is transferred to the base block 4 as schematically shown by arrows in FIG. It is transmitted to the wall of tank 2 via. The heat transmitted to the wall of the tank 2 is conducted in the circumferential direction and the length direction along the wall, and the plate-like rib 8 is provided inside the tank 2 so that the plate-like rib 8 Heat is transmitted to the plate rib 8 and is conducted in the plane direction, and the refrigerant is heated by the wall of the tank 2 and the surface of the plate rib 8 during that time. The refrigerant is boiled by heating, and the vapor rises into each pipe 3 via the upper space of the tank 2, and is condensed by being radiated from the fins 5 at the upper end of these pipes 3. Is lowered again in the pipe 3 and returned to the tank 2.

  At this time, since the wall of the tank 2 is a gentle concave arc wall and the plate-like rib 8 is flat, the heat transmitted from the base block 4 is promptly along the wall of the tank 2 and the surface of the plate-like rib 8. Conduct to. On the other hand, in the vicinity of the joint portion 11 between the plate-like rib 8 and the wall of the tank 2, heat transmitted through the wall of the tank 2 gathers from both sides of the joint portion 11 of the plate-like rib 8 and the wall of the tank 2. The heat conducted in the circumferential direction changes its direction and is transmitted to the plate-like rib 8. For this reason, heat concentrates on the joint 11, the vicinity of the joint 11 becomes particularly high, and boiling starts from corners A on both sides of the joint 11.

Since the plate-shaped rib 8 and the wall of the tank 2 extend above the liquid level L of the refrigerant, most of the surface of the plate-shaped rib 8 can be used widely as a heat transfer area, and from the liquid level L upward. A temperature gradient is generated between the upper end portion which protrudes and has a relatively low temperature and the joint portion 11 where heat concentrates and becomes high temperature. For this reason, the whole of the tank 2 and the plate-like rib 8 does not rise at a uniform temperature, but the whole rises in a state where the connecting portion 11 is hotter than the other portions. Therefore, it is possible to continue the nucleate boiling state starting from the corners A on both sides of the coupling portion 11 that is always in a high temperature state. In addition, since the peripheral wall of the tank 2 and the plate-like rib 8 are integrally formed, heat transfer at these connecting portions 11 can be performed smoothly. Therefore, high heat transfer efficiency can be maintained and cooling performance can be improved.
When the upper end of the plate-like rib 8 is lower than the liquid level L, the heat transfer area is reduced and the heat transfer efficiency is lowered.

FIG. 3 shows a second embodiment of the present invention. In this second embodiment, the height of the plate-like rib 15 is smaller than the diameter of the tank 2, and its upper end is separated from the inner peripheral surface of the tank 2. Are arranged. However, the upper end portion of the plate-like rib 15 protrudes above the coolant level L. Other configurations are the same as those of the first embodiment, and common portions are denoted by the same reference numerals and description thereof is omitted.
Also in the second embodiment, since the plate-like rib 15 protrudes above the liquid level L of the refrigerant, the plate-like rib 15 is caused by the temperature gradient generated in the plate-like rib 15 as in the case of the first embodiment. At the joint 11 between the lower end of the tank and the tank wall, the temperature becomes highest, and the nucleate boiling state can be continued at the corners A on both sides.

  FIG. 4 shows a third embodiment of the present invention. In the third embodiment, the height of the plate-like ribs 16A to 16C is smaller than the diameter of the tank 2 as in the second embodiment, and the upper end is disposed away from the inner peripheral surface of the tank 2. The plate-like ribs 16A to 16C are provided in parallel. In the illustrated example, three plate-like ribs 16 </ b> A to 16 </ b> C are provided at substantially equal intervals so as to partition most of the space except for the upper part in the tank 2 into four groove-like spaces having substantially the same width. Also in this case, the upper ends of the plate-like ribs 16A to 16C protrude above the liquid level L of the refrigerant.

In this 3rd Embodiment, since the corner | angular part A is formed in the both sides of the coupling | bond part 11 of each plate-shaped rib 16A-16C and the wall of the tank 2, nucleate boiling will arise from this corner | angular part A as the starting point. Since there are a plurality of nucleate boiling starting points A, in this case, six locations, the cooling performance can be further improved.
The number of plate-like ribs is not limited to these three.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the said embodiment, although the tank, the plate-shaped rib, and the pipe were formed with copper or a copper alloy, forming with aluminum or an aluminum alloy is not prevented. Moreover, although water was used as the refrigerant, a refrigerant other than water may be used.
Further, the tank may be arranged in a horizontal direction even if it is not arranged strictly horizontally, and the pipe is allowed to be arranged slightly inclined with respect to the vertical. In addition, although this tank has a pipe shape with a round cross section, it may have another shape such as a square cross section.

DESCRIPTION OF SYMBOLS 1 Cooler 2 Tank 3 Pipe 4 Base block 5 Fin 6 Semiconductor element 8 Plate-like rib 9 Semiconductor mounting surface 10 Refrigerant injection pipe 11 Coupling part 15,16A-16C Plate-like rib A Corner | angular part (starting point of nucleate boiling)
L Liquid surface S Heat receiving surface

Claims (3)

A plurality of pipes extending in the vertical direction are arranged side by side in the length direction of the tank, and the upper ends of these pipes are closed, on the upper side of the tank that is disposed sideways and closed at both ends. The lower end portion of the pipe is in communication with the tank, plate-like ribs extending in the vertical direction are provided on the surface of the concave arc wall on the inner bottom surface of the tank, and the refrigerant is disposed on the plate. The tank is sealed so as to form a liquid level below the upper end of the rib, the outer bottom surface of the tank is a heat receiving surface, and the peripheral wall of the tank and the plate rib are integrally formed. A cooler characterized by that.   The cooler according to claim 1, wherein a plurality of the plate-like ribs are provided in parallel with a space between each other. The cooler according to claim 1 or 2, wherein the tank and the plate-like rib are made of copper or a copper alloy.

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