JPS5816639B2 - High cooling performance mounting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a high cooling performance mounting method, more specifically, heat flow generated from electronic circuit elements in three states of heat (radiation, conduction,
The invention relates to a mechanism for efficiently dissipating heat through an effective combination of convection.

Conventionally, with regard to heat dissipation of electronic devices consisting of a group of packages on which electronic circuit components are mounted, since the packages are generally made of a substrate such as epoxy or paper phenol, that is, a high heat resistance base material, the heat generated by the electronic circuit elements is limited. Heat is radiated by conduction to the outside of the package through the internal wiring pattern, but most of the heat is conducted to the space between the packages, raising the temperature of the space. exhaust to the front or back side.

2 However, in order to achieve higher densities due to higher performance of electronic devices, it is difficult to realize a heat dissipation mechanism that fully satisfies the performance of electronic devices using the conventional limited convection heat dissipation method described above. It is possible.

The present invention has been made in order to cope with the conventional situation, and therefore, an object of the present invention is to significantly improve the heat dissipation characteristics described above, and to make it possible to keep up with the increasing density of electronic device packaging. The purpose of this invention is to provide a new high cooling performance heat dissipation method.

The main structure of the present invention is that in order to increase the efficiency of heat dissipation from the electronic elements to the wide heat dissipation surface in contact with the outside world via heat transfer route 1, the board on which the electronic components are mounted is made of a material with low thermal resistance such as ceramic or metal. A low thermal resistance package realized by the body, and a heat transfer highway that conducts the heat flow generated within the low thermal resistance package to a wide heat dissipation surface on the frame's 4th circumference by conduction.
It consists of a side convection guide plate for exhausting the heat flow transferred to the space occupied by the low thermal resistance package, and a frame duct for promoting the convection exhaust.

Next, a detailed description will be given with reference to the drawings.

1. Figures 1a, b, and c are diagrams showing heat dissipation mounting forms of electronic devices that have been conventionally used.Among them, a is a partial front view showing the inside with the frame side cover removed, and b is a partial front view showing the inside of the electronic device. FIG. 3 is a schematic sectional view taken along line bb in FIG. a, and C is a schematic sectional view taken along line cc in FIG.

The configuration of a so-called general electronic device includes a unit in which a group of printed circuit boards 5 on which electronic components 6 are mounted and pladines connected to connectors 7 is stored in a storage shelf 4, and a unit for discharging heat convection generated from the electronic components 6. It has a structure in which it is attached to the frames 11, 1r in combination with the convection guide plate 8, and the four circumferences of the frame are further surrounded by frame side covers 21, 2r, 3f3b.

The heat dissipation method in this configuration is such that since the board 5 is made of a high heat resistance material such as epoxy paper phenol, the heat resistance of the electronic components 6 is also high, and the surface temperature of the components is high.
Laterally adjacent, for example, 5b, 5c, 5d with respect to the substrate 5a
The temperature rise in the space of the substrate 5a is determined by adding the amount of heat generated within the substrate 5a and the amount of heat due to the radiation effect.

The airflow warmed by convection generated by this amount of heat moves upward, but in order to block the influence on the electronic components on the upper stage, the rising airflow is moved by the convection guide plate 8 on the rack side 3f (or 3f).
b).

When the exhaust area is shown in FIG. 1 a and b, it is Xo x y x ho, and heat radiation is performed using this volume space.

Next, the basic heat dissipation principle of the present invention will be explained.

Referring to Figure 1 a and b, the region S8 where the heat source exists
is a volume space of 55=Xoxyoxho, and the conventional convection-based heat dissipation utilization area Sc mentioned above is S C−X o
A volume space of X y X h o is used.

In general, good heat dissipation performance can be defined as reducing the temperature rise depending on the amount of heat generated per unit volume.

Therefore, the objective here is to utilize the volume occupied by the rack with the best performance.

For that purpose, the existing volume Sn of the heat source should be virtually S n
It is necessary to approach = x x y x h.

An example of the space volume ratio of an actual electronic device is So:Sc:5n
=0.4:0.8:1.0.

As can be seen from this example, actual devices do not exhibit sufficient heat dissipation performance.

Means for improving this heat dissipation performance will be explained using FIG. 2.

FIG. 2 is a sectional view similar to FIG. 1 for explaining the basic principle of the present invention.

The heat flow generated by electronic components ultimately takes the process of heat radiation from solid surfaces.

Therefore, the enlargement of the solid surface means an increase in the amount of heat dissipation, and as a result, the temperature rise of the heat source is reduced.

That is, cooling performance is improved.

The present invention focuses on the large heat dissipation surfaces such as the four-side covers 2', 2r, 3f, and 3b, which have not been used for heat dissipation in the past, and uses these large heat dissipation surfaces as solid heat dissipation surfaces, and further expands the heat dissipation surface. For this purpose, additionally provided radiation fins 101, 10r, 101', 10r', etc. are used.

However, in order to expect this heat dissipation effect, the following considerations must be taken into consideration as factors that are not acceptable.

In order for the heat flow generated within the board 5' to be efficiently dissipated on the heat dissipation surface on the four circumferential sides of the rack, the board itself should have a low thermal resistance (e.g., made of ceramic, metal base material, etc.) and be made of a good thermal conductor. By passing through 9b and 9f, heat radiation from the four circumferential sides of the frame is realized.

The good thermal conductor 9b. 9F has a configuration in which the thermal resistance value is as close to zero as possible, so that the board as a heat generation source and the heat dissipation surface on the four sides of the large frame can be virtually considered as one body. Dissipation becomes possible.

The heat dissipation method according to the present invention has four circumferential heat dissipation surfaces 101°10r.
, 101', 10r', both the inner surface and the outer surface of the rack serve as radiation surfaces, so it is possible to obtain a virtual occupied volume (heat dissipation volume: Sn') larger than the physical occupied volume Sn. .

Therefore, due to the relationship of Sn<Sn', high cooling performance that has not been achieved in the past can be achieved.

In addition, the use of the low thermal resistance substrate described above has the effect of alleviating the effects of radiation transmission between the substrates, contributing to improved heat dissipation performance.

On the other hand, in addition to the conventional means mentioned above, the convection airflow that is heat-transferred to the space between the boards at the electronic component mounting board part can be
By connecting them using a convection guide plate 8' (see FIG. 3) that guides convection to 1 and 1r, effective heat dissipation becomes possible.

This is because the frame rod 11.1r functions as a duct for promoting ventilation, so that it is possible to reduce the temperature rise in the space.

Further, as a combined effect, the wind speed between the substrates is increased, and the thermal resistance value of the substrates is further reduced, so that the cooling capacity can be increased.

Next, a preferred embodiment of the present invention will be explained in more detail with reference to FIG.

FIG. 3 is a partial perspective view showing one embodiment of the present invention.

Although this embodiment is an example of a natural air cooling type configuration, the cooling capacity can be further increased if forced convection is implemented using a fan above the ventilation duct 1r and the radiation fin 10r according to the power density of the heat generating board. can.

This forced air cooling type heat dissipation method can be realized by adding a fan to the above-mentioned natural air cooling type, so although it is not particularly given as an example here, it goes without saying that forced air cooling type may be used.

By arbitrarily providing the good heat conductors 9f and 9b shown in this embodiment, the substrate 5', the good heat conductors 9f, and the heat radiation surfaces 2r and 10r are connected, and high heat conduction is achieved throughout the frame. A heat conduction path is formed.

In the present invention, a heat conduction path with high heat conductivity formed of a material with low thermal resistance is defined as a "heat flow highway".

As the good thermal conductors 9b and 9f, for example, a low thermal resistance metal or a heat pipe can be used.

As explained above, if the heat dissipation method according to the present invention is performed,
Compared to conventional methods, cooling capacity can be improved several times in both natural air cooling and forced air cooling.

Therefore, it is possible to have a high-density device configuration, and furthermore, because the temperature of the entire device is made uniform by the heat flow highway configuration described above, it is possible to realize a device with good overall performance in which the operating characteristics of the elements are good. advantage.

has.

It goes without saying that the heat generating elements mentioned here include all of the can type, dual in-line type, and hybrid type.

Although the present invention has been described above with respect to one preferred embodiment thereof, this is merely an example, and it goes without saying that the present invention is not limited to the embodiment described herein.

[Brief explanation of the drawing]

Figures 1a to 1c are diagrams showing heat dissipation of the device configuration in the conventional method, Figure 1a is a partial front view with the side cover of the frame removed, A sectional view taken along line -b and seen in the direction of the arrow, Figure 1C is c- of Figure 1a.
FIG. 2 is a cross-sectional view taken along line c and viewed in the direction of the arrow, FIG. 2 is a diagram illustrating the principle of the present invention, and FIG. 3 is a perspective view showing an embodiment of the present invention. 1 l, 1 r --- frame, 21.2 r, 3 f
, 3b... Frame side cover, 4... Package storage shelf, 5at5b, 5c, 5d, 5'...
...Electronic parts mounting board, 6...Electronic parts,
7... Connector, 8. &'... Convection induction plate, 9b, 9f... Good thermal conductor, 101
゜10 r, 10 l', 10 r'・-・-
Heat dissipation fin, 11-... Connector, mounting plate for package storage shelf, 12-... Frame duct configuration plate.

Claims (1)

[Claims] 1. A plurality of substrates on which electronic components are mounted are formed of low thermal resistance materials, and a part of the heat flow transferred from the surface of the low thermal resistance packages to the space between the low thermal resistance packages is transferred to a side frame using a convection guide plate. The frame rod functions as a duct to promote ventilation, and the heated convective airflow is exhausted, and the radiation heat transmission and reception between the low thermal resistance packages and the heat flow generated within the low thermal resistance package are An air-cooled high-cooling performance mounting method characterized by connecting to the four sides of the rack and connecting it to a heat flow highway that induces heat transfer, and ultimately performing heat dissipation and exhaust treatment using the metal surfaces on the four sides of the rack. .