JP2012164939A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electronic apparatus which prevents damage to a circuit module due to dust and the like contained in cooling air while sufficiently securing cooling performance of the circuit module.SOLUTION: An electronic apparatus has a housing (2) where air intake ports (9a, 9b) and exhaust ports (10a, 10b) are provided. A circuit module (3) generating heat is housed in the housing (2). The circuit module (3) is covered by a cover (28) and is thermally connected with a heat sink (20). The heat sink (20) is exposed in the housing (2). A first ventilation passage (25) and a second ventilation passage (26) are provided in the housing (2). The first ventilation passage (25) and the second ventilation passage (26) are separated from each other in the housing (2). The heat sink (20) is positioned in the first ventilation passage (25) and the cover (28) is exposed in the second ventilation passage (26). Further, a fan (4) is provided in the housing (2). The fan (4) flows cooling air in the first and second ventilation passages (25, 26).

Description

  Embodiments described herein relate generally to an electronic device that houses a circuit module that generates heat inside a housing.

  For example, an electronic device such as a communication amplifier employs a so-called forced air cooling method in which a circuit module housed in a housing is forcibly cooled using a fan.

  The fan increases air permeability inside the casing by sucking air into the casing and discharging it out of the casing. As a result, a flow of cooling air is formed inside the housing, and the circuit module is cooled by this cooling air.

Japanese Patent Laid-Open No. 2004-119844

  Depending on how the electronic device is used, dust, moisture, or the like may be contained in the air sucked into the housing. If dust or moisture in the air adheres to circuit components or conductor patterns constituting the circuit module, it cannot be denied that the circuit module is damaged or causes a failure.

  For this reason, there is a demand for an electronic device that can sufficiently prevent the circuit module from being damaged by dust or the like contained in the cooling air while ensuring sufficient cooling performance of the circuit module.

  According to the embodiment, the electronic device has a housing provided with an air inlet and an air outlet. A circuit module that generates heat is housed inside the housing. The circuit module is covered with a cover and thermally connected to the heat sink. The heat sink is exposed in the housing. A first ventilation path and a second ventilation path are provided inside the housing. The first ventilation path and the second ventilation path are partitioned from each other within the housing. The heat sink is located in the first ventilation path. The cover is exposed to the second ventilation path. Further, a fan is provided in the housing. The fan causes cooling air to flow through the first ventilation path and the second ventilation path.

Sectional drawing of the electronic device which concerns on 1st Embodiment. Sectional drawing which follows the arrow F2-F2 of FIG. The front view of the electronic device seen from the direction of arrow F3 of FIG. Sectional drawing of the electronic device which concerns on 2nd Embodiment. Sectional drawing of the electronic device which concerns on 3rd Embodiment. Sectional drawing which follows the arrow F6-F6 of FIG.

[First Embodiment]
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 3.

  1 and 2 disclose an electronic apparatus 1 such as a communication amplifier. The electronic device 1 is accommodated in a box-shaped pedestal called a cabinet rack, for example. The gantry includes a shelf plate on which the electronic device 1 is installed, an opening for inserting and removing the electronic device 1, and a door for opening and closing the opening.

  For this reason, by opening the door of the gantry, the electronic device 1 placed on the shelf board is exposed from the opening to the outside of the gantry, and for example, maintenance inspection or replacement work of the electronic device 1 can be performed.

  The electronic device 1 is not limited to be used by being housed in a cabinet rack, and may be one that is attached to a utility pole or the like and used outdoors.

  As shown in FIGS. 1 and 2, the electronic device 1 includes a metal housing 2, a circuit module 3, and two electric fans 4.

  The housing 2 has a rectangular box shape, and is composed of, for example, a main body 5 and a top plate 6. The main body 5 includes a bottom plate 7a, a front plate 7b, a back plate 7c, a left side plate 7d, and a right side plate 7e. The front plate 7b, the back plate 7c, and the left and right side plates 7d and 7e are erected from the periphery of the bottom plate 7a and are continuous in the circumferential direction of the main body 5. The top plate 6 closes the openings defined by the upper edges of the front plate 7b, the back plate 7c, and the left and right side plates 7d and 7e.

  As shown in FIGS. 1 and 3, a first air inlet 9 a and a second air inlet 9 b are formed in the front plate 7 b of the housing 2. The first air inlet 9a and the second air inlet 9b have, for example, a slit shape extending in the width direction of the housing 2, and are arranged in parallel with a gap in the height direction of the housing 2.

  A first exhaust port 10 a and a second exhaust port 10 b are formed in the back wall 7 c of the main body 5. The first exhaust port 10a and the second exhaust port 10b are, for example, circular holes that are separated from each other in the width direction of the housing 2 and that the first intake port 9a and the second intake port 9b Located on the opposite side.

  A pair of metal brackets 11 a and 11 b are fixed to the inner surfaces of the side plates 7 d and 7 e of the housing 2. The brackets 11 a and 11 b extend over the entire length of the housing 2 along the depth direction. Each of the brackets 11 a and 11 b has a flange portion 12. The flange portion 12 projects horizontally from the inner surfaces of the side plates 7 d and 7 e toward the inside of the housing 2, and faces each other in the width direction of the housing 2.

  The circuit module 3 is accommodated in the housing 2. The circuit module 3 includes a printed wiring board 14 and a plurality of circuit components 15. The printed wiring board 14 has a first surface 14a on which a plurality of pads and conductive patterns are formed, and a second surface 14b located on the opposite side of the first surface 14a.

  Further, a through hole 16 is formed at the center of the printed wiring board 14. The through hole 16 is opened in the first surface 14 a and the second surface 14 b of the printed wiring board 14.

  The circuit component 15 is mounted on the first surface 14 a of the printed wiring board 14. The circuit component 15 includes a semiconductor package 17. The semiconductor package 17 enters the through hole 16 of the printed wiring board 14 and is soldered to a pad on the first surface 14a. The bottom of the semiconductor package 17 is exposed on the same surface as the second surface 14 b of the printed wiring board 14 through the through hole 16.

  For example, a specific circuit component 15 such as a resistor and the semiconductor package 17 are examples of a heating element that generates heat during operation. The circuit component 15 and the semiconductor package 17 that generate heat require cooling in order to maintain normal operation. Therefore, the circuit module 3 of this embodiment is supported by the housing 2 via the heat sink 20 as shown in FIGS.

  The heat sink 20 is made of, for example, an aluminum alloy having excellent thermal conductivity. The heat sink 20 has a base 21 and a plurality of heat radiating fins 22. The base 21 is a square plate and has a width dimension straddling between the flange portions 12 of the brackets 11a and 11b. The left and right side edge portions of the base 21 are fixed on the flange portion 12 via a plurality of screws, respectively.

  The base 21 has a first surface 23a and a second surface 23b. The first surface 23 a faces the bottom plate 7 a of the housing 2. The second surface 23 b is located on the opposite side of the first surface 23 a and faces the top plate 6 of the housing 2.

  The heat radiating fins 22 protrude from the first surface 23 a of the base 21 and are exposed inside the housing 2. The heat radiating fins 22 extend straight in the depth direction of the housing 2 and are arranged at intervals in the width direction of the housing 2.

  The circuit module 3 is supported on the second surface 23 b of the base 21. Specifically, the printed wiring board 14 of the circuit module 3 is fixed to the second surface 23b of the base 21 via a plurality of screws. By this fixing, the second surface 14 b of the printed wiring board 14 is in surface contact with the second surface 23 b of the base 21, and the printed wiring board 14 is thermally connected to the base 21.

  Further, the semiconductor package 17 accommodated in the through hole 16 of the printed wiring board 14 is fixed to the second surface 23b of the base 21 via a plurality of screws. By this fixing, the bottom of the semiconductor package 17 is in surface contact with the second surface 23 b of the base 21, and the semiconductor package 17 is thermally connected to the base 21.

  As shown in FIGS. 1 and 2, the brackets 11 a and 11 b and the base 21 of the heat sink 20 cooperate with each other to partition the inside of the housing 2 into a first ventilation path 25 and a second ventilation path 26. Yes. The first air passage 25 is located between the base 21 and the bottom plate 7a of the housing 2, and the first air inlet 9a and the first and second air outlets 10a and 10b of the housing 2 are connected to each other. Between. The first surface 23 a of the base 21 and the heat radiating fins 22 are located in the first ventilation path 25.

  The second ventilation path 26 is located between the base 21 and the top plate 6 of the housing 2. The second ventilation path 26 connects the second intake port 9b of the housing 2 and the first and second exhaust ports 10a and 10b. The downstream end of the first ventilation path 25 and the downstream end of the second ventilation path 26 are joined together inside the housing 2. A junction 27 between the first ventilation path 25 and the second ventilation path 26 is located immediately before the first and second exhaust ports 10a and 10b.

  As shown in FIGS. 1 and 2, the circuit module 3 on the base 21 is covered with a box-shaped cover 28. The cover 28 is made of a metal material having excellent thermal conductivity, such as an aluminum alloy. The cover 28 is supported by the base 21, and one end is abutted against the inner surface of the front plate 7 b of the housing 2. Therefore, the cover 28 forms a sealed space 29 that accommodates the circuit module 3 in cooperation with the base 21 and the front plate 7b.

  The cover 28 is exposed in the second ventilation path 26. In other words, the cover 28 isolates the sealed space 29 in which the circuit module 3 is accommodated from the second ventilation path 26 so that the circuit module 3 is not exposed in the second ventilation path 26.

  As shown in FIG. 1, the electric fan 4 is attached to the back plate 7c of the housing 2 so as to correspond to the first and second exhaust ports 10a and 10b.

  The electric fan 4 includes a fan casing 31 and an impeller 32. The fan casing 31 has a suction port 33 and a discharge port 34. The suction port 33 communicates with the first and second exhaust ports 10a and 10b. The discharge port 34 is opened outside the housing 2. The impeller 32 is supported by the fan casing 31 and is positioned between the suction port 33 and the discharge port 34.

  When the impeller 32 rotates, the air inside the housing 2 is sucked into the electric fan 4 from the first and second exhaust ports 10a and 10b. Thereby, the air outside the housing 2 is taken into the upstream end of the first ventilation path 25 from the first intake port 9a and taken into the upstream end of the second ventilation path 26 from the second intake port 9b. It is. The air taken into the first and second ventilation paths 25 and 26 becomes cooling air and flows through the first and second ventilation paths 25 and 26 toward the first and second exhaust ports 10 and 10b. .

  Most of the heat generated by the semiconductor package 17 is directly transferred to the base 21 of the heat sink 20. At the same time, most of the heat generated by the circuit component 15 is transferred to the base 21 via the printed wiring board 14. The heat transmitted to the base 21 is released to the first ventilation path 25 from the first surface 23 a of the base 21 and the outer peripheral surface of the radiating fin 22.

  Furthermore, the temperature of the sealed space 29 rises due to the radiant heat from the semiconductor package 17 and the circuit component 15. At the same time, the cover 28 becomes high temperature under the influence of the radiant heat of the semiconductor package 17 and the circuit component 15. The heat transferred to the cover 28 is released from the surface of the cover 28 to the second ventilation path 26.

  According to the first embodiment, air outside the housing 2 is individually taken into the first ventilation path 25 and the second ventilation path 26 as the electric fan 4 operates. The air taken into the first ventilation path 25 becomes cooling air as shown by an arrow A in FIG. 1 and flows through the first ventilation path 25 toward the first and second exhaust ports 10a and 10b. .

  That is, the cooling air flowing through the first ventilation path 25 passes between the heat radiation fins 22 of the heat sink 20. Thereby, heat exchange is performed between the radiating fins 22 and the cooling air, and the heat transmitted to the radiating fins 22 is carried away by the flow of the cooling air. As a result, heat dissipation from the heat sink 20 is promoted. The cooling air warmed by heat exchange with the heat radiating fins 22 is discharged out of the housing 2 through the electric fan 4 from the first and second exhaust ports 10 a and 10 b of the housing 2.

  On the other hand, the air taken into the second ventilation path 26 becomes cooling air as shown by an arrow B in FIG. 1, and directs the second ventilation path 26 toward the first and second exhaust ports 10a and 10b. Flowing.

  That is, the cooling air passes through the second ventilation path 26 along the surface of the cover 28. Thereby, heat exchange is performed between the cover 28 and the cooling air, heat dissipation from the cover 28 is promoted, and a temperature rise in the sealed space 29 is suppressed. The cooling air heated by heat exchange with the cover 28 is discharged out of the housing 2 through the electric fan 4 from the first and second exhaust ports 10a and 10b of the housing 2.

  According to such a first embodiment, the heat sink 20 thermally connected to the circuit module 3 is cooled by the cooling air flowing through the first ventilation path 25, and the cover 28 that receives the radiant heat of the circuit module 3 is The air is cooled by the cooling air flowing through the second ventilation path 26.

  In other words, the cold air outside the housing 2 is individually guided to both the heat sink 20 and the cover 28. As a result, the heat sink 20 is not affected by the heat of the cooling air heated by the heat exchange with the cover 28, and the cover 28 is not affected by the heat of the cooling air heated by the heat exchange with the heat sink 20. Absent.

  Therefore, the ambient temperature of the circuit module 3 covered with the cover 28 can be kept low while actively releasing the heat of the circuit module 3 from the heat sink 20. Therefore, sufficient cooling performance of the circuit module 3 can be ensured.

  Moreover, since the circuit module 3 is accommodated in the sealed space 29 isolated from the second ventilation path 26, the circuit module 3 is not directly exposed to the flow of the cooling air. For this reason, it is possible to avoid dust such as dust or moisture contained in the cooling air from adhering to the pads and the conductor pattern of the printed wiring board 14. Therefore, damage or failure of the circuit module 3 can be prevented, and the reliability of the operation of the electronic device 1 can be improved.

  In the first embodiment, the downstream end of the first ventilation path and the downstream end of the second ventilation path are joined together just before the exhaust port, but the downstream ends of both the ventilation paths remain separated from each other. You may make it communicate with an exhaust port in the state of.

  Furthermore, the cover that covers the circuit module is not limited to metal but may be made of resin, for example. In this case, when electromagnetic shielding performance is required for the cover, it is desirable to perform metal plating on the surface of the cover.

  In addition, the number of fans is not limited to the first embodiment, and for example, the air in the housing may be sucked by one fan.

[Second Embodiment]
FIG. 4 discloses a second embodiment.

  The second embodiment is different from the first embodiment in that the flow rate of the cooling air flowing through the first ventilation path is made larger than the amount of cooling air flowing through the second ventilation path. Other configurations of the electronic apparatus are the same as those in the first embodiment. Therefore, in the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 4, a control plate 41 is disposed at a junction 27 between the downstream end of the first ventilation path 25 and the downstream end of the second ventilation path 26. The control plate 41 is fixed to the rear surface of the cover 28 facing the back plate 7 c of the housing 2 and extends in the width direction of the housing 2.

  Further, the control plate 41 is arranged so that the flow of cooling air from the downstream end of the second ventilation path 26 toward the first and second exhaust ports 10a and 10b is restricted from the rear surface of the cover 28 to the back plate of the housing 2. It protrudes diagonally toward 7c. The front end of the control plate 41 crosses the upper portions of the first and second exhaust ports 10a and 10b immediately before the back plate 7c.

  For this reason, due to the presence of the control plate 41, the opening areas of the first and second exhaust ports 10 a and 10 b with respect to the downstream end of the second flow passage 26 are changed into the first and second openings with respect to the downstream end of the first flow passage 25. It is narrower than the opening area of the two exhaust ports 10a, 10b.

  According to the second embodiment, the control plate in which the flow of the cooling air from the downstream end of the second ventilation path 26 toward the first and second exhaust ports 10 a and 10 b is arranged in the merge portion 27. It is squeezed by 41.

  For this reason, the electric fan 4 sucks more air in the first ventilation path 25 than air in the second ventilation path 26, and the amount of cooling air flowing through the first ventilation path 25 is the second. The amount of cooling air flowing through the ventilation path 26 is increased. The ratio between the amount of cooling air flowing through the first ventilation path 25 and the amount of cooling air flowing through the second ventilation path 26 is preferably 7: 3, for example.

  As a result, the cooling air can be sufficiently guided to the heat sink 20 that directly receives the heat of the circuit module 3. Therefore, the heat dissipation performance of the heat sink 20 can be promoted, and the cooling performance of the circuit module 3 can be enhanced.

  Means for increasing the amount of cooling air flowing through the first ventilation path 25 more than the amount of cooling air flowing through the second ventilation path 26 is not limited to the control plate. For example, the discharge port of the electric fan is individually connected to the downstream end of the first ventilation path and the downstream end of the second ventilation path, and the suction performance of the electric fan corresponding to the first ventilation path is set to the second ventilation path. It is also possible to increase the suction performance of the electric fan corresponding to the above.

[Third Embodiment]
5 and 6 disclose a third embodiment.

  The third embodiment is different from the first embodiment in the configuration in which the heat sink is supported by the housing. Other configurations of the electronic apparatus are the same as those in the first embodiment. Therefore, in the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIGS. 5 and 6, a plurality of support columns 51 are fixed to the bottom plate 7 a of the housing 2. The column 51 is erected vertically from the bottom plate 7a. The base 21 of the heat sink 20 is superimposed on the upper end surface of the support column 51 and is fixed to the support column 51 via a plurality of screws 52. For this reason, the base 21 of the heat sink 20 is separated from the bottom plate 7 a of the housing 2 by an amount corresponding to the height of the column 51.

  As shown in FIG. 6, the base 21 and the cover 28 of the heat sink 20 are separated from the left side plate 7 d and the right side plate 7 e of the housing 2. Accordingly, a first gap 53a is formed between the base 21 and the cover 28 and the left side plate 7d of the housing 2, and a second gap 53b is formed between the base 21 and the cover 28 and the right side plate 7e of the housing 2. Is formed between.

  Therefore, in the third embodiment, the first ventilation path 25 and the second ventilation path 26 communicate with each other through the first and gaps 53a and 53b.

  According to the third embodiment, the heat sink 3 thermally connected to the circuit module 3 is cooled by the cooling air flowing through the first ventilation path 25, and the cover 28 that receives the radiant heat of the circuit module 3 is Cooled by the cooling air flowing through the second ventilation path 26.

  From this, the cold air outside the housing 2 is individually guided to the heat sink 3 and the cover 28. Therefore, the heat sink 3 is hardly affected by the cooling air heated by the heat exchange with the cover 28, and the cover 28 is hardly affected by the cooling air heated by the heat exchange with the heat sink 3. Therefore, the same effect as that of the first embodiment can be obtained.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 2 ... Housing, 3 ... Circuit module, 4 ... Fan (electric fan), 9a, 9b ... Intake port (1st inlet port, 2nd inlet port), 10a, 10b ... Exhaust port (1st exhaust port) , Second exhaust port), 15, 17 ... heating elements (circuit parts, semiconductor package), 20 ... heat sink, 25 ... first ventilation path, 26 ... second ventilation path, 28 ... cover, 41 ... means ( Control board).

Claims (12)

A housing having an air inlet and an air outlet;
A heat generating circuit module housed in the housing;
A cover that covers the circuit module in the housing;
A heat sink thermally connected to the circuit module and exposed in the housing;
A first ventilation path provided in the housing so as to connect the intake port and the exhaust port, and the heat sink is located;
A second ventilation path provided in the casing so as to connect between the intake port and the exhaust port, the cover is exposed, and the first ventilation path is partitioned from the first ventilation path in the casing;
A fan that is provided in the housing and causes cooling air to flow through the first ventilation path and the second ventilation path;
An electronic device comprising   2. The heat sink according to claim 1, wherein the heat sink includes a first surface and a base having a second surface positioned on the opposite side of the first surface, and the first ventilation path extending from the first surface of the base. A plurality of heat dissipating fins projecting toward the electronic device, wherein the circuit module is supported on the second surface of the base.   3. The electronic device according to claim 2, wherein the circuit module includes a wiring board and a heating element mounted on the wiring board, and the wiring board and the heating element are thermally connected to the base.   4. The electronic device according to claim 3, wherein the cover forms a sealed space that accommodates the circuit module in cooperation with the base, and the sealed space is isolated from the second ventilation path in the housing. machine.   5. The downstream end of the first ventilation path and the downstream end of the second ventilation path are joined together in the housing and communicated with the exhaust port, and the fan is An electronic device that sucks air in the first ventilation path and the second ventilation path through the exhaust port. A housing having an exhaust port;
A heat generating circuit module housed in the housing;
A cover that covers the circuit module in the housing;
A heat sink thermally connected to the circuit module and exposed in the housing;
A first ventilation path provided in the housing and in which the heat sink is located;
A second ventilation path provided in the housing and exposing the cover;
A fan that is provided in the housing and causes cooling air to flow through the first ventilation path and the second ventilation path;
Means for increasing the flow rate of the cooling air flowing through the first ventilation path more than the flow rate of the cooling air flowing through the second ventilation path;
An electronic device comprising   7. The apparatus according to claim 6, wherein the means includes a control plate that restricts the flow of air from the downstream end of the second ventilation path toward the exhaust port, and the control plate is a downstream end of the first ventilation path. And an electronic device provided at a junction between the second ventilation path and the downstream end of the second ventilation path. A housing,
A heating element housed in the housing;
A cover that covers the heating element in the housing;
A heat sink thermally connected to the heating element and exposed in the housing;
A first ventilation path provided in the housing and through which air for cooling the heat sink flows;
A second ventilation path provided in the housing and through which air for cooling the cover flows;
An electronic device comprising   9. The electronic device according to claim 8, wherein the heat sink is located in the first ventilation path.   10. The electronic device according to claim 9, wherein the cover receives heat from the heating element and is exposed to the second ventilation path.   The heat sink according to claim 10, wherein the heat sink includes a first surface and a base having a second surface positioned on the opposite side of the first surface, and the first air passage from the first surface of the base. A plurality of heat dissipating fins protruding toward the electronic device, wherein the heating element is thermally connected to the second surface of the base.   12. The cover according to claim 11, wherein the cover forms a sealed space that accommodates the heating element in cooperation with the base, and the sealed space is separated from the second ventilation path in the housing. machine.

Images