RU2374792C1 - Radio electronic unit and cooling method thereof - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: radio electronic unit includes metal housing inside which radio elements are located. There is coating on the external housing side, which is made from heat conducting material and which has thermal conductivity which is higher than that of metal housing, and has anisotropic thermal conductivity. Heat loaded radio elements are located on external housing side. Cooling method of radio electronic unit involves arrangement of radio elements inside the housing; heat loaded radio elements are arranged on external housing side, and non heat loaded elements are located inside housing. To external housing side there applied is coating with anisotropic thermal conductivity; at that, cooling of radio electronic unit is performed together with heat transfer along external coating of the housing and heat dissipation of the whole external surface of radio electronic unit to environment. Heat energy distribution rate along external coating of the housing is higher than that inside the unit.

EFFECT: improving operating reliability by increasing cooling effectiveness, electromagnetic screening, namely in tight radio electronic units.

8 cl, 2 dwg

Description

FIELD OF THE INVENTION

The invention relates to electronics and can be used in electronic blocks to solve problems of increasing operational reliability by increasing the cooling efficiency, electromagnetic shielding and method of cooling, in particular, in sealed radio electronic blocks.

State of the art

A technical solution is known (Patent RU No. 2262815 "Heat-radiating radiator and method of heat radiation using it, publ. 2005.10.20), where the heat-radiating radiator contains a main body and a metal coating layer of a thickness not exceeding 5 microns made of elements of the group containing copper , nickel, cobalt, chromium, zinc, manganese or their alloys, while the heat capacity of the said layer of metal coating is less than the heat capacity of the main body. Heat-loaded elements are located inside the main body and have thermal contact on the inside of the body. The method of heat radiation using a heat-radiating radiator provides for supplying air fluid to the surface of the radiator using a fan mounted on it.

The disadvantage of this technical solution is that the heat-loaded elements produce heat transfer inside the device, violating the thermal regime, which leads to a decrease in cooling efficiency. The presence of a fan and air inlet and outlet openings impairs electromagnetic shielding.

The closest technical solution (prototype) is “Heat-emitting panel and method of cooling with its use” (Patent RU No. 2129246, publ. 1999.04.20).

The casing of the device in the form of a panel placed between the high-temperature and low-temperature zones consists of a metal plate and a layer forming a thermal gradient deposited on the surface of the plate facing the low-temperature zone. The layer forming the thermal gradient is made of a heat-conducting material having a heat capacity and the ability to absorb thermal radiation less than that of a metal plate. The heat capacity of the layer forming the thermal gradient does not exceed 10% of the heat capacity of the metal plate, and the ability to absorb thermal radiation does not exceed 60% of the similar ability of the metal plate, which will prevent overheating of the device inside which heat generation occurs.

The disadvantage of this technical solution is that the heat-loaded elements produce heat transfer inside the housing, violating the heat regime, the heat flow directed from the inside through the metal plate leads to heating of the plate itself, which further exacerbates the thermal regime of the internal volume of the device and, as a result, reduces the operational reliability; cooling performance drops. The thermal gradient layer does not provide electromagnetic protection.

A technical solution is known (Application RU No. 2001113266 “Method and system for cooling the housing with heat-generating elements located therein”, publ. 2003.06.10), where an inlet is made in the housing through which air, an outlet, enters from the outside through which air exits from the casing to the outside and a radiator with a heat-dissipating fin is installed in it, a radiator with a heat-dissipating fin is partially or completely placed inside the casing near the inlet and air is passed into the casing through the inlet hardening, first through a radiator with a heat-dissipating fin, while taking heat from it emitted by a working, heat-generating element, after which a heat passing through a radiator with a heat-dissipating fin and heated air in it is released through the outlet of the case, cooling the case itself . To pump air through the housing, a fan is used, which is installed next to the outlet of the housing. This method is an analog of the cooling method.

This method of cooling the housing reduces operational reliability due to the fact that the heat-loaded and non-heat-loaded elements are located inside the housing. A radiator with a heat-dissipating fin is partially or completely located inside the unit, which contributes to the additional heating of non-heat-loaded elements. The presence of a fan, inlet and outlet openings complicates the design and reduces the effectiveness of electromagnetic shielding.

Known technical solution (Patent RU No. 2268439 "Method of thermal and mechanical protection of the object", publ. 2006.01.20), which is the prototype of the cooling method. A method of thermal and mechanical protection of an object, including its placement inside a protective laminate, consisting of successively arranged layers: an external shock-resistant layer made of heat-resistant metals, an intermediate heat-protective layer made of refractory dry porous material, and an internal heat-protective layer formed of a water-containing material enclosed between the outer and inner heat-reflecting gaskets on the outer surface of the outer shock-resistant layer additionally form a bimorph heat-insulating coating of a heat-insulating composite material having adhesion to the surface of the outer shock-resistant layer and the ability to increase its volume by at least 10 times when exposed to a flame by heat, for which the outer surface of the outer shock-resistant layer is coated with a heat-insulating composite material in a fluid state and perform the operation of hardening the material by heating it to a hardening temperature, while the external shock and heat -term layer is perforated with through drainage holes.

The above method allows you to protect the internal elements from thermal heating, but does not solve the problem of cooling the heat-loaded elements of this device. The provision of thermal insulation occurs by increasing the volume of the outer layer by at least 10 times, which affects the operational reliability of both nearby devices and the device itself. The presence of perforated through holes reduces the effectiveness of electromagnetic protection.

Disclosure of invention

The technical result of the present invention is to increase operational reliability by increasing the cooling efficiency, electromagnetic shielding, in particular in sealed radio electronic units.

The technical result is achieved by the fact that the electronic unit contains a metal casing, inside of which there are radio elements. On the outside of the casing there is a coating of heat-conducting material, which has greater thermal conductivity than the metal casing and has anisotropic thermal conductivity. Heat-loaded radio elements are placed on the outside of the case.

Thermal energy is distributed along the outer surface of the housing, preventing the spread of heat inside the electronic unit.

Moreover, the coating with anisotropic thermal conductivity is multilayer.

Moreover, the coating with anisotropic thermal conductivity has conductive properties.

Moreover, the metal case on the inside is coated with nickel and copper.

Moreover, the metal case on the outside has cooling fins.

Moreover, the metal case on the outside has recesses for accommodating heat-loaded elements.

Moreover, the recesses for accommodating the heat-loaded elements are provided with covers.

A method of cooling a radio-electronic unit, in which radioelements are placed inside the housing, heat-loaded radioelements are placed on the outside of the housing, and non-heat-loaded elements are placed inside the housing. An anisotropic thermal conductivity coating is applied to the outer side of the casing, and the radio-electronic unit is cooled simultaneously with heat transfer along the external casing and heat dissipation by the entire outer surface of the radio-electronic block into the surrounding space. The rate of propagation of thermal energy over the outer coating of the housing is higher than the rate of propagation of thermal energy into the unit.

Brief Description of the Drawings

The invention, its feasibility and the possibility of industrial application are illustrated by the drawings, presented in figures 1, 2.

Figure 1 shows the electronic block in cross section (recesses for installing heat-loaded elements are located in the side parts of the block).

Figure 2 shows an isometric electronic block in a general view (recesses for installing heat-loaded elements are located in the rear of the block).

The inventive electronic block contains:

1 - metal case;

2 - radioelements;

3 - the outer side (surface) of the housing;

4 - coating forming anisotropic thermal conductivity;

5 - the inner side of the housing;

6 - cooling fin;

7 - a recess for accommodating heat-loaded elements;

8 - heat-loaded element;

9 - a cover;

10 - non-loaded electronic unit;

11 - output heat-loaded element;

12 - dielectric sealant;

13 - wire;

14 - hole.

The implementation of the invention

The electronic block contains a metal casing 1 (Figs. 1, 2), inside of which there are radioelements 2. On the outer side 3 of the metal casing 1, an anisotropic thermal conductivity coating 4 of heat-conducting material is applied, heat-loaded elements 8 are placed on the outer side 3 of the metal casing 1, with side forming anisotropic thermal conductivity of the coating 4 of a heat-conducting material, and said coating 4 has a higher thermal conductivity than the metal housing 1, and has a direction of the spread of thermal energy on the outer surface 3 (figure 2) of the housing 1, preventing the spread of heat inside the electronic unit. The heat-conducting coating is made, for example, of a graphite film (Sergey Ozerov, article "Hygienic pads". Computerra magazine, No. 14 of April 14, 2005). The thermal conductivity of crystalline graphite is anisotropic and in the plane of the layers it is much larger than perpendicular to the layers. A film made of graphite spreads heat remarkably over its area. Thus, graphite does not give local overheating, and the heat goes away faster than penetrates through. The industrial technology for producing highly efficient heat-conducting graphite films (Pyrolitic Graphite Sheet, PGS) is developed and used by Matsushita Electronics for flexible heat dissipation in several laptops. The Russian company "ARMO-Graphite" industrially uses domestic graphite films. Thus, for the external side of the housing of the electronic block, you can use both PGS foreign gasket and ARMO-Graphite domestic gasket with gluing, for example, heat-conducting adhesive OUTPUT 384 manufactured by Loctite or graphite adhesive LEIT-C.

Moreover, the inner side 5 of the metal housing 1 of the electronic unit has a metal coating of nickel, copper, for example nickel-copper-nickel (H3.M9.H6). The metal case 1 on the outer side 3 has cooling ribs 6 and recesses 7 for accommodating the heat-loaded elements 8. Moreover, the recesses 7 for accommodating the heat-loaded elements 8 are provided with covers 9. The heat-loaded elements 8 with their leads 11 exit into the internal volume of the radio electronic unit, and the place the output of the terminals 11 of the heat-loaded elements 8 is filled in with a dielectric sealant 12, for example, a Vixint U 4-21 sealant. The findings of the heat-loaded elements 11 are electrically connected to non-heat-loaded electronic nodes 10 using wire 13.

Moreover, the coating with anisotropic thermal conductivity 4 is multilayer.

Moreover, the coating with anisotropic thermal conductivity 4 has conductive properties.

In the method of cooling a radio electronic unit, radio elements 2 are placed inside the housing 1, and a coating is applied to the outer side 3 of the housing 1. Heat-loaded radio elements 8 are placed on the outer side 3 of the housing 1, and non-heat-loaded elements 10 are placed on the inside of the housing 1. The outer side 3 of the housing 1 is coated with anisotropic thermal conductivity, while the electronic unit is cooled simultaneously with the heat transfer along the outer coating 4 of the housing 1 and heat dissipation the entire outer surface 3 of the electronic unit into the surrounding space. The rate of propagation of thermal energy over the outer coating of the housing is higher than the rate of propagation of thermal energy into the unit.

The essence of the invention lies in the fact that the separation of the heat-loaded elements 8 and non-heat-loaded electronic components 10 with the corresponding elements so that the non-heat-loaded elements 10 remain inside the metal casing 1 of the electronic unit, and the heat-loaded elements 8 are outside; heat from the heat-loaded elements 8 cannot be transferred by convection into the inside of the unit and the radiating effect inside the radio-electronic unit is minimized by the fact that the heat-loaded element 8 is installed on the outer side of the metal casing 1 of the electronic block, and an anisotropic thermal conductivity 4 is applied to the outer side 3 of the metal casing 1 having conductive properties.

The method of cooling the electronic block is that the rate of distribution of thermal energy on the outer side of the metal casing is higher than the rate of distribution of thermal energy inside the electronic block, which contributes to more efficient heat transfer to the environment.

The cooling method is based on a new principle that allows highly efficient heat dissipation into the external environment, minimizing the penetration of heat inside the electronic unit, which ensures high operational reliability.

From the above it follows that the claimed invention is technically feasible, industrially feasible and solves the technical problem.

Claims (8)

1. A radio electronic unit comprising a metal casing, inside of which there are radioelements, moreover, on the outside of the casing there is a coating of thermally conductive material, characterized in that the heat-loaded radioelements are placed on the outside of the casing, said coating having a higher thermal conductivity than the metal casing, and has anisotropic thermal conductivity. 2. The electronic unit according to claim 1, characterized in that the coating with anisotropic thermal conductivity is multilayer. 3. The electronic unit according to claim 2, characterized in that the coating forming anisotropic thermal conductivity has conductive properties. 4. The electronic unit according to claim 3, characterized in that the metal housing is coated with nickel and copper from the inside. 5. The electronic unit according to claim 4, characterized in that the metal housing on the outside has cooling fins. 6. The electronic unit according to claim 5, characterized in that the metal case on the outside has recesses for accommodating heat-loaded elements. 7. The electronic unit according to claim 6, characterized in that the recesses for accommodating the heat-loaded elements are provided with covers. 8. A method of cooling a radio-electronic unit, according to which radioelements are placed inside the housing, and a coating is applied to the outer side of the housing, characterized in that heat-loaded radioelements are placed on the external side of the housing, and non-loaded elements are placed inside the housing, and anisotropic coating is applied to the external side of the housing thermal conductivity, while the cooling of the electronic unit occurs simultaneously with heat transfer along the outer coating of the housing and heat dissipation of the entire outer surface Stu avionics unit into the surrounding space.

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