JP5354786B2 - Heat dissipation structure for vehicle meters - Google Patents

Description

  The present invention relates to a heat dissipation structure for a vehicle instrument, and more particularly to an improved technique for improving waterproof performance and heat dissipation efficiency.

  Some automobile meters are equipped with a display such as a fluorescent display tube or a liquid crystal, and this display is driven by an electronic circuit to perform digital display. In this type of automotive instrument, generally, an electronic circuit is covered with a metal cover having a heat radiating opening, and the electronic circuit radiates heat through the heat radiating opening (see, for example, FIG. 3 of Patent Document 1). ). The heat radiation opening according to this example has a plurality of circular through holes, so that heat generated inside the instrument can be radiated from the through hole to the outside of the instrument.

Japanese Utility Model Publication No. 60-37818

  However, in the heat dissipation structure having a plurality of through holes, a sufficient opening area cannot be secured, and high heat dissipation efficiency cannot be obtained. In addition, in the case of a heat dissipation structure in which the heat dissipation opening surface is erected only by forming a through hole in the heat dissipation opening surface, there is a possibility that water flowing down the outer surface of the heat dissipation opening surface may enter the inside of the instrument from the through hole. there were.

  The present invention has been made in view of the above situation, and an object thereof is to provide a heat dissipating structure for a vehicle instrument capable of improving the waterproof performance and heat dissipating efficiency of the instrument back cover having a heat dissipating opening. .

The above object of the present invention is achieved by the following configuration.
(1) A heat dissipating structure for a vehicle instrument comprising a wiring board, a heat sink fixed to the wiring board, and an instrument back cover that covers the wiring board and the heat sink from the back side,
The heat sink is provided with a plurality of horizontal fins spaced apart in the vertical direction in multiple stages,
The heat-dissipating section of the instrument back cover has a heat-dissipating opening, and the heat-dissipating opening is provided with a plurality of inclined pieces that are inclined downward toward the outside of the instrument. Each heat dissipation opening is formed,
The fins and the heat radiation openings are arranged on the same horizontal plane,
A heat dissipating structure for a vehicular instrument, wherein a position of a lower end of each of the inclined pieces is made to coincide with the heat dissipating opening surface .

  According to this heat dissipation structure for a vehicle instrument, a heat dissipation opening is formed in the instrument back cover along the fin shape, and heat from the fin is discharged outside the instrument without being blocked by the instrument back cover, thereby efficiently dissipating heat. Is possible. The distance from the fin to the heat radiation opening becomes the shortest, and efficient heat radiation becomes possible. The inclined piece forming the heat radiating opening is inclined downward toward the outside of the meter, and water flowing downward on the heat radiating opening surface outside the meter does not enter the inside of the meter.

(2) The vehicle instrument heat dissipating structure of (1),
A heat dissipating structure for a vehicle instrument, wherein an upper end of the inclined piece has a return portion bent in a vertical direction.

  According to the heat dissipating structure of the vehicle instrument, the water spray that tries to crawl up the inclined piece upward from the heat radiating opening hits the return portion extending vertically upward, and flows down along the inclined piece by gravity. The entrance to the inside of the instrument is prevented, and the waterproof performance at the heat radiation opening is further enhanced.

(3) (1) or (2) a vehicle instrument heat dissipation structure,
The height of the heat radiating openings, heat radiation structure of an instrument for a vehicle, wherein the same or a larger value der Rukoto the thickness of the fin.

  According to this heat dissipating structure for a vehicle instrument, the discharge space sandwiched between the fin front and back surfaces extends in a protruding direction toward the outside of the instrument of the fin, and is linearly secured to the outside of the instrument without being blocked by the instrument back cover. The Thereby, the opening for heat radiation which does not block the linear exhaust heat from the fin can be secured at the minimum height, and it is difficult for water from the outside to enter.

  According to the heat dissipating structure for a vehicle instrument according to the present invention, a heat dissipating opening corresponding to the tip of the horizontal fin of the heat sink is formed in the heat dissipating opening surface of the instrument back cover, and the lower end is formed on the heat dissipating opening surface below the heat dissipating opening. Since the downwardly inclined slope pieces that are matched with each other are provided, the heat radiation opening of the instrument back cover can be formed along the fin shape, and the waterproof performance and the heat radiation efficiency can be improved.

It is a perspective view of the instrument back surface cover which has the heat dissipation structure concerning the present invention. It is a front view of the instrument back surface cover shown in FIG. It is BB sectional drawing of FIG. It is a principal part expanded sectional view of the thermal radiation structure shown in FIG. It is operation | movement explanatory drawing of the thermal radiation structure by embodiment. It is a perspective view of the thermal radiation structure which concerns on the comparative example by which the opening for thermal radiation was formed in the instrument back surface cover. It is a front view of the instrument back surface cover shown in FIG. It is AA sectional drawing of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of an instrument back cover having a heat dissipation structure according to the present invention.
In the present embodiment, a case where the vehicle meter provided with the heat dissipation structure is a combination meter will be described as an example. In addition, if the heat dissipation structure which concerns on this invention is a vehicle instrument which incorporates the wiring board used as a heat source, it will be suitable also if it uses it for instruments other than a combination meter.

  The combination meter includes a speedometer, a tachometer, a fuel meter, a fluorescent display tube, a power transistor, and a wiring board. The fluorescent display tube receives power from the power transistor and displays the instrument image on the display surface. The fluorescent display tube is mounted on the mounting surface on the wiring board, and the display surface is positioned on the vehicle compartment side in this mounted state of the wiring board.

  Therefore, the wiring board becomes a heat source. The wiring board is arranged on the back side of the instrument of the combination meter, and this back side of the instrument is covered with a back cover 11 of the instrument. A rectangular heat radiating section 15 is provided on the outer surface 13 of the instrument back cover 11. The heat radiating section 15 has a heat radiating opening surface 17 that protrudes from the outer surface 13 and becomes a flat surface. The heat radiation opening surface 17 includes tip surfaces of a plurality of inclined pieces, which will be described later, and a heat radiation opening.

FIG. 2 is a front view of the instrument back cover shown in FIG.
A plurality of heat radiation openings 19 are formed in the heat radiation section 15, and the heat radiation openings 19 are formed in a horizontally long slit shape on the heat radiation opening surface 17 and are vertically separated (up and down in FIG. 2). The heat radiation opening 19 communicates the inside of the meter to the outside of the meter so that heat can be exhausted.

3 is a cross-sectional view taken along line BB in FIG.
In the combination meter, the above-mentioned wiring board 21 in which an electronic circuit is formed is fixed upright in the vertical direction (vertical direction in FIG. 3). The wiring board 21 is the above-mentioned fluorescent display tube, power transistor, etc., which are mounted electrical components. It becomes a heat source by conducting heat released from.

  A heat sink 23 is fixed to the surface of the wiring board 21 that faces the instrument back cover 11, and the heat sink 23 has a plurality of fins 25 that are horizontally spaced apart in a vertical direction. The tips of the fins 25 are arranged so as to coincide with the heat radiation openings 19 of the instrument back cover 11. That is, the wiring board 21 provided with the heat sink 23 is covered with the instrument back cover 11, and heat from the fins 25 is discharged from the heat radiation opening 19 to the outside.

  Below each heat radiation opening 19 is a downward slope toward the instrument exterior 27 (see FIG. 4), and the position of the lower end in the downward direction is a heat radiation opening surface (the extended surface is indicated by a two-dot chain line in FIG. 3) 17. An inclined piece 29 is provided so as to match the above. The inclined piece 29 is formed by bending an upper edge of a strip having a constant width and the same length into a square shape, and extends with the vertical direction in FIG. 3 as the longitudinal direction. Both ends of the inclined piece 29 are fixed to the side frames 31 and 31 (see FIG. 1) of the heat radiation section 15.

FIG. 4 is an enlarged cross-sectional view of a main part of the heat dissipation structure shown in FIG.
The inclined piece 29 is formed in a U-shape so that the upper end becomes a return portion 33 bent in the vertical direction. The heat radiation opening 19 is formed between the inclined pieces 29 spaced apart from each other in the vertical direction. In the present embodiment, the height h of the heat radiation opening 19 is set to be the same as the thickness t of the fin 25 (h = t). The height h of the heat radiation opening 19 may be larger (h> t) as long as the thickness t of the fin 25 is secured.

  Above the uppermost inclined piece 29, the upper frame 35 of the heat radiating section 15 is extended to the heat radiating opening surface 17 as a frame piece 37 having the same inclination angle as that of the inclined piece 29. A lower frame 39 of the heat radiating section 15 is disposed below the lowermost inclined piece 29, and a lower opening 41 (see FIG. 3) is formed.

Next, the operation of the heat dissipating structure of the vehicle instrument configured as described above will be described together with the operation of the heat dissipating opening according to the comparative example.
FIG. 5 is an explanatory diagram of the operation of the heat dissipation structure according to the present embodiment, FIG. 6 is a perspective view of a heat dissipation structure according to a comparative example in which an opening for heat dissipation is formed in the instrument back cover, and FIG. 7 is the instrument back cover shown in FIG. FIG. 8 is a cross-sectional view taken along the line AA of FIG.
Prior to describing the operation of the heat dissipation structure according to the present invention, the configuration and operation of the heat dissipation structure according to the comparative example will be described.
In the heat radiation structure according to the comparative example, a rectangular heat radiation partition portion 505 is provided on the outer surface 503 of the instrument back cover 501 shown in FIG. 6, and the heat radiation partition portion 505 protrudes from the outer surface 503 and becomes a flat heat radiation opening surface 507. Have As shown in FIG. 7, a plurality of heat radiation openings 509 are formed in the heat radiation section 505, and the heat radiation openings 509 are horizontally long slit-shaped through holes punched out from the heat radiation opening surface 507. ).

  As shown in FIG. 8, a wiring board 511 formed with an electronic circuit is erected and fixed in the vertical direction (vertical direction in FIG. 8) in the automobile meter, and the wiring board 511 is heat released from the mounted electrical components. It becomes a heat source by being conducted. A heat sink 513 is fixed to the surface of the wiring board 511 facing the instrument back cover 501, and the heat sink 513 has a plurality of fins 515 that are horizontally spaced apart in a vertical direction. The tips of the fins 515 are arranged so as to coincide with the heat radiation openings 509 of the instrument back cover 501. In the heat dissipation structure in this automobile instrument, heat from the fins 515 can be discharged to the outside from the heat dissipation opening 509, but the heat dissipation opening 509 becomes a horizontally long slit-shaped through hole punched out from the heat dissipation opening surface 507. High waterproof performance is difficult to obtain.

  On the other hand, in the heat radiation opening according to the present embodiment, the heat radiation opening 19 is formed in the instrument back cover 11 along the fin shape, and the heat Q (see FIG. 5A) from the fin 25 is generated by the instrument back cover. 11 is discharged to the outside 27 of the instrument without being obstructed by 11 and efficient heat dissipation becomes possible. In the configuration in which the heat radiation opening 19 does not coincide with the tip of the fin 25, as shown in FIG. 5B, the heat Q from the fin 25 is blocked by the inclined piece 29, for example, and the heat radiation efficiency is lowered.

  Further, since the heat radiation opening 19 coincides with the tip of the fin 25, the distance L1 from the fin 25 to the heat radiation opening 19 becomes the shortest, and efficient heat radiation is possible. In the configuration in which the heat radiation opening 19 does not coincide with the tip of the fin 25, the distance L2 from the fin 25 to the heat radiation opening 19 is longer than L1 (L1 <L2), as shown in FIG. descend.

  Further, as shown in FIG. 3, the inclined piece 29 forming the heat radiation opening 19 is inclined downward toward the instrument exterior 27, so that the water 43 flowing downward on the heat radiation opening surface 17 in the instrument exterior 27 is generated. It will not enter the inside 45 of the instrument.

  Furthermore, as shown in FIG. 4, a splash 49 that tries to scoop up the inclined piece 29 upward from the heat radiation opening 19 hits the return portion 33 that stands vertically upward, and flows down along the inclined piece 29 by gravity. Thus, entry into the instrument interior 45 is blocked. Thereby, the waterproof performance in the heat radiation opening 19 is further enhanced.

  Moreover, the discharge space 51 (see FIG. 4) sandwiched between the fin front and back surfaces extends in the protruding direction of the fin 25 toward the instrument exterior 27, and is linearly secured to the instrument exterior 27 without being blocked by the instrument back cover 11. Is done. As a result, the heat radiation opening 19 that does not block the linear exhaust heat from the fin 25 can be secured with the minimum height h, and the entry of water from the outside due to the heat radiation opening 19 becoming larger than necessary is prevented. Has been.

  Therefore, according to the heat dissipating structure of the vehicle instrument according to the present embodiment, the heat dissipating opening 19 that coincides with the tip of the horizontal fin of the heat sink 23 is formed in the heat dissipating opening surface 17 of the instrument back cover 11 and below the heat dissipating opening 19. Since the downwardly inclined sloped piece 29 having the lower end coincided with the heat radiation opening surface 17 is provided on the side, the heat radiation opening 19 of the instrument back cover 11 is formed along the fin shape to improve the waterproof performance and the heat radiation efficiency. Can do.

11 Instrument Back Cover 19 Heat Dissipation Opening 17 Heat Dissipation Opening Surface 21 Wiring Board 23 Heat Sink 25 Fin 27 Instrument External 29 Inclined Piece 33 Return Part h Heat Dissipation Opening Height t Fin Thickness

Claims (3)

A heat dissipating structure for a vehicle instrument comprising a wiring board, a heat sink fixed to the wiring board, and an instrument back cover that covers the wiring board and the heat sink from the back side,
The heat sink is provided with a plurality of horizontal fins spaced apart in the vertical direction in multiple stages,
The heat-dissipating section of the instrument back cover has a heat-dissipating opening, and the heat-dissipating opening is provided with a plurality of inclined pieces that are inclined downward toward the outside of the instrument. Each heat dissipation opening is formed,
The fins and the heat radiation openings are arranged on the same horizontal plane,
A heat dissipating structure for a vehicular instrument, wherein a position of a lower end of each of the inclined pieces is made to coincide with the heat dissipating opening surface . A heat dissipating structure for a vehicle instrument according to claim 1,
A heat dissipating structure for a vehicle instrument, wherein an upper end of the inclined piece has a return portion bent in a vertical direction. A heat dissipation structure for a vehicle instrument according to claim 1 or 2,
The height of the heat radiating openings, heat radiation structure of an instrument for a vehicle, wherein the same or a larger value der Rukoto the thickness of the fin.

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