JPH09213849A - Cooler of liquid-cooled heat sink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform heat radiation effective for cooling a semiconductor element large in generation loss, by self cooling method of natural cooling, without using a rotor short in life such as a cooling fan, etc., but using liquid good in heat conductivity such as oil, etc., by arranging the vanes of a vane part in radial form in circumferential direction. SOLUTION: The vanes 41 of a vane part are arranged in radial form all around the periphery, and the contact faces are united by brazing to an element mounting plate 42 by vane mounting plates 43. Moreover, though the vanes 41 are made of plates the same in height, thickness, and length, they are arranged alternately to have longitudinal differences ΔL in circumference. This way, oil cooled all around the case flows in the fin vane part by arranging the vane structure of the heat sink in radial form, so the cooling efficiency is remarkably improved. Moreover, the action of the guide of cooling oil flowing into the vane part of the fin can be expected by providing a difference ΔL in level in longitudinal direction, and the heat radiation effect of the heat sink can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling fin cooling device that radiates heat generated by a semiconductor element through a liquid having a good heat transfer coefficient.

[0002]

2. Description of the Related Art A power converter using a semiconductor element is
With the development of high-performance elements and the development of PWM control technology, there is a tendency for high-frequency switching due to the need for higher performance of devices and lower noise due to the trend toward inverters.
When this converter is used for high frequency switching,
The loss of a semiconductor element used as a switching element such as an IGBT increases in proportion to the switching frequency, and an effective cooling method is required.

Conventionally, in a heat sink for cooling these semiconductor elements, generally, the blades are arranged in a balanced manner, and cooling air is taken in by a cooling fan from the front or rear of the heat sink, and cooling is performed by a so-called forced ventilation system. Is going. In this case, the ventilation cooling blows air through the cooling fan motor that rotates at high speed, so there are parts such as bearings that wear, and the heat generated by the heat sink reduces the life of the cooling system. Conducts regular inspections and replaces the cooling fan motor once every 4 to 5 years.

FIG. 3 is a plan view showing the arrangement of the heat sink blade portion 41 when the inside of the conventional oil case is viewed from above, and the oil cooled by the heat radiation from the side surface of the oil case 1 to the outside air is arranged in parallel. Although it enters the blade, in this embodiment, it enters the blade portion 41 from both side surfaces of the case, but the cooling oil in the vertical direction is not effectively utilized.

FIG. 4 is a plan view showing another conventional example. In this case, the oil cooled from the side surface of the case can flow into the vane portion 41 of the heat sink from four directions of the case,
A certain degree of cooling effect can be expected. However, in the case of such a circular case, the cooling oil taken in by the blade part partially radiates the heat radiation area of the case to the outside air (about 1/3 in this example).
It is only used for.

[0006]

SUMMARY OF THE INVENTION The present invention was devised in view of the above-mentioned points, and an object of the present invention is not to use a rotating body having a short life such as a cooling fan or a pump.
(EN) A cooling device for a heat sink for cooling, which radiates heat effectively to cool a semiconductor element with a large loss generated by a natural cooling self-cooling method using a liquid having a good heat transfer coefficient such as oil.

[0007]

[Means for Solving the Problems] That is, the means for achieving the object is a heat sink for cooling heat generated from a semiconductor element with a liquid such as oil in a heat radiating fin. The blades are arranged in a radial pattern in the circumferential direction. Then, a plurality of blades radially arranged in the circumferential direction may be arranged with a step in the circumferential length direction. That is,
In order to effectively guide the oil cooled by the outside air to the blade portion of the heat sink, it is effective to orient the blade toward the case surface that cools the oil.

In the case of applying a fin having the blades arranged in parallel to each other, which has been conventionally used for ventilation cooling, to the heat radiating portion of the heat sink, as a cooling liquid, a transformer, a reactor and a resistor are generally used in a converter using a semiconductor. Since high-frequency current also flows to other main motor circuit devices that make up the device and generates a large amount of heat, it also serves as a cooling liquid for these conductive parts.Therefore, insulating oil such as transformer oil is used as the cooling liquid. It

Further, the heat radiated into the oil is radiated from the surface of the oil case by natural convection or heat radiation from the surface of the case to the outside air by using a radiating fin having a high radiating efficiency.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a blade structure of a heat sink according to the present invention. FIG. 1 (a) is a plan view of the heat sink as seen from above the blade portion, and FIG. 1 (b) is a side view thereof.
In FIG. 1, the blades 41 of the blade portion are arranged radially over the entire circumference, and the element attachment plate 42 is integrated with the blade attachment plate 43 by contacting the contact surface. The blade 41 is provided with a step difference ΔL in the length direction for every other flat plate having the same height, the same thickness, and the same length with respect to the outer peripheral direction.

FIG. 2 is a block diagram showing a case where these blades are housed in an electronic device, which is an electronic device incorporating a power conversion device composed of an oil case 1 and a device case 2, in which a heat sink is attached to a bottom surface 12 of the oil case 1. 4, the semiconductor element 5 such as an IGBT constituting the power converter is mounted on the element mounting plate 42 on the lower surface of the heat sink, and the heat generated by the loss generated by the semiconductor element 5 is applied to the blade portion of the heat sink 4 in the oil case 1. Then, the semiconductor element 5 is cooled by radiating heat from the surface of the blade 41 into the cooling oil 3.

In this case, a transformer,
Other accessories that normally generate heat, such as the reactor 8 and the resistor 6, are also accommodated, so the cooling oil 3 is
Use highly insulating oil such as transformer oil.

Since the heat generated from these devices has a heat transfer coefficient of oil that is 5 times higher than that of air, the oil that has become hot due to heat dissipation is natural convection and moves to the upper part of the case as shown in (a) in the figure. After that, as shown in (b), it moves to the case side, and heat is dissipated to the outside air from the case side, so the oil cooled on the case side circulates along the side to the lower part of the case as shown in (c). The heat radiated to the heat sink 4 is cooled. Reference numerals 13 and 14 are mounting metal fittings for mounting the reactor 5 and the resistor 6 to the lid 11, and 7 is an electronic component such as a gate circuit for driving a semiconductor element.

[0014]

As described above, according to the present invention, by making the blade structure of the heat sink radial, the cooled oil flows into the fin blade portion over the entire circumference of the case, so that the cooling efficiency is remarkably improved. To be done. Further, by providing a step in the length of the blade of the heat sink over the entire circumferential direction, the action of the guide of the cooling oil flowing into the blade portion of the fin can be expected, and the heat dissipation effect of the heat sink can be improved.

[Brief description of drawings]

FIG. 1 is a blade configuration diagram showing an embodiment of a heat sink of the present invention.

FIG. 2 is a schematic diagram of an electronic structure having a heat sink cooled by a liquid such as oil according to the present invention.

FIG. 3 is a plan view showing an example of a conventional heat sink.

FIG. 4 is a plan view showing another example of a conventional heat sink.

[Explanation of symbols]

 1 Oil Case 2 Equipment Case 3 Oil 4 Heat Sink 41 Vane 42 Mounting Plate 43 Vane Mounting Plate 5 Semiconductor Element 6 Electronic Component 7 Electronic Component 8 Transformer, Reactor 11 Lid 12 Key Bottom Plate 13 Mounting Bracket 14 Mounting Bracket

Claims (2)

[Claims] 1. In a heat sink for cooling heat generated from a semiconductor element with a liquid such as oil to cool the blades of a fin for heat radiation, the blades of the blades are radially arranged in the circumferential direction. A cooling device for a liquid cooling heat sink, which is characterized in that: 2. The cooling device for a liquid cooling heat sink according to claim 1, wherein the plurality of blades radially arranged in the circumferential direction are arranged with a step in the length direction of the circumferential direction.