JP7110599B2 - Electronics - Google Patents

Description

The present invention relates to electronic equipment.

In Patent Document 1, bimetals are arranged between a heat sink and a radiator plate and between a substrate and a radiator plate. It is described that the heat generated by the electronic components is dissipated to the outside of the housing through each heat sink.

JP 2009-193350 A

In the above-described prior art, since a thin bimetal is included in the heat dissipation path to be switched, there is a problem that heat resistance is increased and heat dissipation cannot be sufficiently ensured.

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-described problems of the prior art, and provides an electronic device capable of ensuring sufficient heat dissipation from internal electronic components and improving the low-temperature resistance of the electronic components. for the purpose.

An electronic device according to the present invention is an electronic device including a component carrier assembly that carries an electronic component, a support mechanism that supports the component carrier assembly, and a hollow housing surrounding the component carrier assembly and the support mechanism. hand,
A heat conductor disposed inside the housing facing the electronic component,
The support mechanism brings the electronic component into contact with the heat conductor at a temperature inside the housing that exceeds a predetermined temperature, and keeps the electronic component out of contact with the heat conductor at a temperature inside the housing that is equal to or lower than the predetermined temperature. and a temperature sensitive actuator for positioning the component carrier assembly so as to allow the component carrier assembly to be actuated.

According to the present invention, since the electronic device includes the temperature-sensitive actuator, it is possible to obtain the effect of ensuring sufficient heat dissipation and improving the low-temperature resistance of the electronic component.

1 is a schematic exploded perspective view showing an electronic device that is Embodiment 1 according to the present invention; FIG. FIG. 2 is a perspective view showing the appearance of the electronic device of Example 1 as viewed from the lid side; 3 is a schematic cross-sectional view of the electronic device taken along line xx in FIG. 2; FIG. 1 is a schematic cross-sectional view of an electronic device of Example 1 according to the present invention; FIG. 2 is a schematic cross-sectional view of an electronic device of Example 2 according to the present invention; FIG. 2 is a schematic cross-sectional view of an electronic device of Example 2 according to the present invention; FIG. 3 is a schematic cross-sectional view of an electronic device of Example 3 according to the present invention; FIG. 3 is a schematic cross-sectional view of an electronic device of Example 3 according to the present invention; FIG. It is a schematic sectional view of the electronic device of Example 4 by this invention. It is a schematic sectional view of the electronic device of Example 4 by this invention. It is a schematic sectional view of the electronic device of Example 5 by this invention. It is a schematic sectional view of the electronic device of Example 5 by this invention.

Electronic devices according to embodiments of the present invention will be described below with reference to the drawings. In addition, the present invention is not limited to the following examples. In addition, in the embodiments, components having substantially the same functions and configurations are denoted by the same reference numerals, thereby omitting redundant description.

(Description of configuration)
FIG. 1 is a schematic exploded perspective view showing an electronic device 11 that is Embodiment 1. FIG. FIG. 2 is a schematic perspective view (a part of the inside is indicated by a dashed line) showing the appearance of the housing 12 of the electronic device of Example 1, viewed from the lid side. FIG. 3 is a schematic cross-sectional view showing a cross section of the electronic device 11 taken along line xx in FIG.

As shown in FIGS. 1 to 3, the housing 12 of the electronic device 11 of Example 1 has a substantially rectangular parallelepiped appearance. As shown in the figure, an electronic circuit board 15 (component support assembly) is accommodated in a housing 12 (lid 13 and housing body 14). Various electronic components are mounted on the electronic circuit board 15 in the figure to form an electronic circuit. , other electronic components are omitted. A pair of cylindrical box-shaped lid 13 and housing body 14 are fitted together at their respective openings to form housing 12, and housing 12 supports and positions electronic circuit board 15 inside thereof. It houses the mechanism 17 (bias spring 18 and bimetallic strip 19). Although not shown, packing is sandwiched between the facing surfaces of the openings of the housing body 14 and the lid body 13, and the housing body 14 and the lid body 13 are fastened with screws or the like (not shown). is fixed.

A radiator plate 21 made of metal or the like is provided on the inner wall (bottom surface) of the housing body 14 so as to face the electronic components 16 of the electronic circuit board 15 . Thermal conductive sheets 22 having flexibility are provided so as to face each other. The heat sink 21 and the heat conductive sheet 22 form a heat conductor 23 for dissipating heat generated by the electronic component 16 to the housing body 14 when the electronic component 16 contacts the heat conductive sheet 22 (see FIG. 3). The heat-conducting sheet 22 is a thermal interface material member that fills small gaps and irregularities between the heat-generating element and the heat sink and efficiently transfers heat to the heat sink.

A bias spring 18 (an elastic member such as a coil spring) of the support mechanism 17 is provided on the inner wall (bottom surface) of the housing body 14 so as to support the edge of the lower surface of the electronic circuit board 15 . In order to align the bias springs 18 and the electronic circuit board 15, the bottom surface of the housing body 14 is provided with annular grooves (not shown) into which the lower ends of the respective bias springs 18 are fitted. An annular groove 15a into which the upper end of the bias spring 18 is fitted is provided (FIG. 1).

A bimetal strip 19 of the support mechanism 17 is provided on the side wall of the housing body 14 so as to support the edge of the upper surface of the electronic circuit board 15 . A set of four pairs of bias springs 18 and bimetal strips 19 facing each other is provided so as to surround the periphery of the electronic circuit board 15 , supporting and positioning the electronic circuit board 15 therebetween. The bimetal strip 19 is a strip-shaped plate body in which two metal plates having different coefficients of thermal expansion are pasted together on their main surfaces. As the plate expands more than the low thermal expansion metal plate, the whole bends toward the low thermal expansion metal plate. In order to utilize this curving characteristic, each of the bimetal strips 19 is fitted with a fan-tenon-shaped base 19a at one end thereof into a mortise hole 14a in the inner wall (side wall) of the housing body 14 and screwed (not shown). is fixed in a cantilever configuration (Fig. 1).

The bimetal strip 19 is arranged such that the other end (free end) of the bimetal strip 19 urges the electronic circuit board 15 downward (first direction) toward the thermally conductive sheet 22 as the temperature inside the housing 12 rises. be. On the other hand, the bias spring 18 is arranged between the electronic circuit board 15 and the bottom surface of the housing body 14 (preferably near the free end of the bimetallic strip 19), and is directed upwardly to separate the electronic component 16 from the thermally conductive sheet 22. (opposite direction of the first direction). That is, the support mechanism 17 (bimetal strip 19 and bias spring 18) supports the electronic circuit board 15 while sandwiching it from the front and back. Acts as an actuator.

A restraining portion ST for restraining movement of the electronic circuit board 15 is provided on the bottom surface of the housing body 14 facing the electronic circuit board 15 . The restraining portion ST regulates the amount of downward (first direction) movement of the electronic circuit board 15 urged by the free end of the bimetal strip 19 due to temperature rise, so that the electronic component 16 is strongly pressed against the heat conductive sheet 22 . to prevent it from being damaged. The height (thickness) of the restraining portion ST and the heat conductor 23 (the heat sink 21 and the heat conductive sheet 22) from the bottom surface of the housing body 14 is equal to the height of the electronic component 16 from the bottom surface of the electronic circuit board 15. In consideration of this, each setting is made so that the heat generated by the electronic component 16 is radiated to the housing main body 14 by contacting the heat conductive sheet 22 with appropriate pressure during the temperature raising operation. The material and shape of the bimetal strip 19 are set so that the free end of the bimetal strip 19 curves at a predetermined temperature so as to bring the electronic circuit board 15 into contact with the restraining portion ST. In this way, the support mechanism 17 keeps the electronic component 16 in contact with the heat conductive sheet 22 at a temperature exceeding a predetermined temperature, and keeps the electronic component 16 out of contact with the heat conductive sheet 22 at a temperature not higher than the predetermined temperature. Position the circuit board 15 .

Examples of housing resin materials for the lid 13 and housing body 14 include engineering plastics such as ABS (acrylonitrile-butadiene-styrene), ASA (acrylate-styrene-acrylonitrile), and AES (acrylonitrile-ethylene-propylene-diene-styrene). . Moreover, the lid 13 and the housing main body 14 may be formed using a metal material.

Although not shown, the housing 12 is provided with a connection hole in a part of the side wall for passing an external power supply cable, an input/output cable, etc. for operating an electronic circuit via an external connection terminal. there is

(Description of operation)
FIG. 4 shows a state in which the electronic component 16 and the thermally conductive sheet 22 are out of contact before the bimetal strip 19 supporting the electronic circuit board 15 is deformed at low temperature. 3 shows a state in which the electronic component 16 is in contact with the heat conductive sheet 22 after the bimetal strip 19 is deformed at a high temperature for urging the electronic circuit board 15. As shown in FIG.

As shown in FIG. 4, when the outside air temperature and the inside temperature of the housing are low and the bimetal strip 19 is not deformed, a gap is opened between the electronic component 16 and the heat conductive sheet 22 due to the reaction force of the bias spring 18. Both are thermally isolated. Therefore, even if the temperature of the housing 12 becomes low due to the influence of the outside air temperature, it is possible to prevent the temperature of the electronic components 16 from excessively decreasing due to the self-heating of the electronic components 16 . When the outside air temperature rises, the bimetal strip 19 deforms and pushes the electronic circuit board 15 into the state shown in FIG. The restraining portion ST on the bottom surface of the housing body 14 determines the amount of movement of the electronic circuit board 15 so that excessive stress is not applied when the electronic component 16 is pressed against the heat conductive sheet 22 . Since the electronic component 16 is in contact with the heat conductive sheet 22 when the temperature is high, the heat generated by the electronic component 16 is transferred to the heat dissipation plate 21 through the heat conductive sheet 22 . Therefore, the temperature rise of the electronic component 16 can be prevented.

As described above, according to the first embodiment, when the outside air temperature is low, the electronic component 16 and the housing 12 are thermally isolated to alleviate the temperature drop of the electronic component 16, and when the outside temperature is high, , the electronic component 16 and the housing 12 are thermally connected to reduce the temperature rise of the electronic component 16 . In addition, when the temperature is high, the heat conductive sheet 22 can be brought into contact with the entire surface of the electronic component 16, and only the heat conductive sheet 22 is sandwiched between the heat sink 21 and the electronic component 16. resistance can be very small.

(Description of configuration)
In this embodiment, instead of the pair of bimetal strips 19 provided on the opposing side walls of the housing body 14 of the first embodiment, as shown in FIG. A cantilever beam portion CLT is provided on the side wall, and one bimetal strip 19A extending from the end portion to above the pair of bias springs 18 is fixed at its center portion, and both ends of the bimetal strip 19A heat the electronic circuit board 15. It is the same as Example 1 except that it is configured to bias downward (first direction) toward the conductive sheet 22 .

(Description of operation)
FIG. 6 shows a state in which the electronic component 16 and the heat conductive sheet 22 are out of contact before the bimetal strip 19A supporting the electronic circuit board 15 is deformed at low temperatures. 5 shows a state in which the electronic component 16 is in contact with the heat conductive sheet 22 after the bimetal strip 19A is deformed at a high temperature for urging the electronic circuit board 15. FIG.

As described above, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and a longer bimetal strip 19A than that of the first embodiment can be used. one direction) can be increased. In addition, since one set of two bimetal strips is replaced with one bimetal strip, the effect of increasing the effectively usable space volume of the electronic circuit board 15 in the housing can be obtained.

(Description of configuration)
In this embodiment, in place of the pair of bimetal strips 19 and the corresponding pair of bias springs 18 provided on the opposite side walls of the housing body 14 of the first embodiment, as shown in FIG. The center of the bimetal strip 19B extends over the side walls of the housing 12 and is fixed to the opposite side walls of the housing 12. 1 direction) and one bias spring 18B is arranged below the center of the bimetal strip 19B.

(Description of operation)
FIG. 8 shows a state in which the electronic component 16 and the heat conductive sheet 22 are out of contact before the bimetal strip 19B supporting the electronic circuit board 15 is deformed at low temperatures. 7 shows a state in which the electronic component 16 is in contact with the heat conductive sheet 22 after the bimetal strip 19B is deformed at a high temperature for urging the electronic circuit board 15. FIG.

As described above, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and a longer bimetal strip 19B than that of the first embodiment can be used. one direction) can be increased. In addition, since one set of two bimetal strips is replaced with one bimetal strip, the effect of increasing the effectively usable space volume of the electronic circuit board 15 in the housing can be obtained.

(Description of configuration)
In this embodiment, instead of the pair of bimetal strips 19 provided on the opposite side walls of the housing body 14 of the first embodiment, one end of the bimetal strip 19 is provided on the bottom surface of the housing 12 as shown in FIG. The other end of the shape memory alloy coil spring 25 moves the electronic circuit board 15 downward toward the heat conductive sheet 22 (first It is the same as the first embodiment except that it is configured to urge in the direction ).

In this embodiment, shape memory alloys such as Ni--Ti alloys and Cu--Zn--Al alloys are soft at low temperatures below a predetermined temperature and hard at high temperatures above a predetermined temperature. In the support mechanism 17 shown in FIG. 9, the electronic circuit board 15 is set so that the shape memory alloy coil spring 25 and the opposing bias spring 18 (such as SUS) press each other.

(Description of operation)
When the temperature is low (FIG. 10), the shape memory alloy coil spring 25 is soft and biased by the bias spring 18 to move upward, so that the electronic component 16 and the heat conductive sheet 22 are out of contact. Then, when the temperature rises (FIG. 9), the shape memory alloy coil spring 25 recovers its original shape with a strong force and expands, pushing back the bias spring 18 to move the electronic circuit board 15 downward, and the electronic component 16 heats up. It will be in contact with the conductive sheet 22 . The support mechanism 17 moves the electronic circuit board 15 upward again when the temperature drops (FIG. 10), and the overall bi-directional movement depends on the temperature.

As described above, according to this embodiment, the same effects as those of the first embodiment can be obtained. In addition, since the bimetal strip is a plate made of different metals laminated together, the movement is limited to the direction perpendicular to the laminated surface, but since the shape memory alloy is a single material, the material itself has no direction dependency, and the wire is formed into a coil spring shape. With the shape memory alloy coil spring 25, the spring length operation stroke can be greatly increased. Therefore, the amount of movement of the electronic circuit board 15 in the downward direction (first direction) can be increased by the shape memory alloy coil spring 25 having a small volume, and the effect of increasing the effectively usable space volume of the electronic circuit board 15 in the housing is obtained. can get.

(Description of configuration)
In this embodiment, in place of the holding portion 25a and the shape memory alloy coil spring 25 held by the holding portion 25a of the fourth embodiment, a shape memory alloy coil spring 25A is mounted on the electronic circuit board 15 coaxially with the bias spring 18 as shown in FIG. , one end of which is directly fixed to the bottom surface of the housing 12 and the other end of which is directly fixed to the electronic circuit board 15 in the same manner as the bias spring 18 .

In this embodiment, the shape memory alloy coil spring 25A is set so as to recover its original shape (when the temperature is high) to the shrunk shape as shown in FIG. It stretches softly on the low temperature side below a predetermined temperature, and recovers its hard property to a shrunk shape on the high temperature side above the predetermined temperature. In the support mechanism 17 shown in FIG. 11, each of the shape memory alloy coil springs 25A is coaxial with each of the bias springs 18 and is set to carry the electronic circuit board 15. As shown in FIG.

(Description of operation)
When the temperature is low (FIG. 12), the shape memory alloy coil spring 25A is soft and is stretched by the bias spring 18 so that the electronic component 16 and the heat conductive sheet 22 are out of contact. Then, when the temperature rises (FIG. 11), the shape memory alloy coil spring 25A recovers its shape with a strong force and contracts, compressing the bias spring 18 to move the electronic circuit board 15 downward, and the electronic component 16 becomes a thermal conductive sheet. 22 is brought into contact. The support mechanism 17 moves the electronic circuit board 15 upward again when the temperature drops (FIG. 12), and the overall bi-directional movement depends on the temperature.

As described above, according to the present embodiment, the same effect as in the fourth embodiment can be obtained, and the support mechanism 17 including the shape memory alloy coil spring 25A coaxial with the bias spring 18 makes the support mechanism 17 compact. It is possible to obtain the effect of increasing the effective use space volume of the electronic circuit board 15 in the housing with a small volume.

In all of the above-described embodiments, examples of application to electronic components mounted on a substrate have been described, but the present invention can also be applied to all heat generating elements housed in a housing such as a power supply unit. Also, the electronic equipment in any of the above embodiments is suitable for electronic equipment installed outdoors.

Further, although the coil spring-shaped bias spring 18 is used in the first to third embodiments, the bending elasticity of a leaf spring formed in a cantilever shape on the side wall of the housing is used as the bias spring instead. It may be something to do.

DESCRIPTION OF SYMBOLS 11... Electronic equipment 12... Case 13... Lid body 14... Case main body 15... Electronic circuit board 16... Electronic component 17... Support mechanism 18... Bias spring 19... Bimetal strip 21... Radiation plate 22... Thermal conductive sheet 23... Heat Conductor ST... Deterrence part

Claims (5)

An electronic device including a component carrying assembly that carries an electronic component, a support mechanism that supports the component carrying assembly, and a hollow housing that surrounds the component carrying assembly and the support mechanism,
A heat conductor disposed inside the housing facing the electronic component,
The support mechanism brings the electronic component into contact with the heat conductor at a temperature inside the housing that exceeds a predetermined temperature, and keeps the electronic component out of contact with the heat conductor at a temperature inside the housing that is equal to or lower than the predetermined temperature. a temperature sensitive actuator for positioning the component carrier assembly to allow
The temperature sensitive actuator comprises a bimetallic strip having a center or both ends fixed to the inner wall of the housing, the ends or the center biasing the component carrier assembly in a first direction toward the thermal conductor. and electronic devices. The support mechanism is positioned proximate the temperature sensitive actuator between the component carrier assembly and the inner wall of the housing, and moves the component carrier assembly away from the thermal conductor to move the component carrier assembly away from the thermal conductor. 2. The electronic device according to claim 1 , further comprising a bias spring that biases the device in one opposite direction. 3. The electronic device according to claim 1, wherein the support mechanism includes a restraining portion that restrains movement of the component support assembly between the component support assembly and the inner wall of the housing. 3. The thermal conductor includes a heat sink provided on the inner wall of the housing so as to face the electronic component, and a heat conductive sheet provided on the heat sink. The electronic device according to any one of 1. 5. The electronic device according to claim 1 , wherein a plurality of said temperature-sensitive actuators are provided so as to surround the periphery of said component support assembly.

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