JP2018098086A - Heat radiation structure for vehicular lighting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat radiation structure for vehicular lighting capable of assuring a required heat radiation performance even if a vehicle is stopped and capable of restricting against increasing in temperature of a light source by a simple constitution.SOLUTION: This invention relates to a heat radiation structure for vehicular lighting 1 provided with a semiconductor light-emitting element (a light source) 6 and with a heat sink (a radiator) 11 for radiating heat generated at the semiconductor light-emitting element 6. The heat radiation structure for vehicular lighting 1 is constituted in such a way that said heat sink 11 is internally installed at a heat radiation part 14B of a duct 14 including an intake part 14A opened as an intake port 14a at one end, said heat radiation part 14B extending in a vertical direction and an exhaust part 14C opened as an exhaust port 14b at one end. A heat radiation of said heat sink 11 is promoted by air flowing from said intake port 14a into said duct 14 and discharged from said exhaust port 14b to cool said semiconductor light-emitting element 6 and then heat insulation characteristics at wall surfaces of the intake part 14A, the heat radiation part 14B and the exhaust part 14C of said duct 14 are differentiated.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a heat dissipation structure for a vehicular lamp that cools a light source by promoting heat dissipation of a radiator installed in a duct by air flowing in the duct.

  2. Description of the Related Art In recent years, semiconductor light emitting devices such as LEDs (light emitting diodes) having high luminous efficiency, high brightness, and power saving have been used as light sources for vehicle lamps such as headlamps arranged on the left and right of the front part of a vehicle. It's getting on. Although this type of semiconductor light emitting device has the above-mentioned advantages, it has a problem that it tends to become high temperature due to heat generation, and the light emission efficiency and life are reduced when the temperature increases.

  Therefore, in a vehicular lamp that uses a semiconductor light emitting element as a light source, it is necessary to cool the semiconductor light emitting element by appropriate means. For this reason, for example, Patent Document 1 proposes a heat dissipation structure shown in FIG.

  7 is a longitudinal sectional view showing a heat dissipation structure for a vehicle lamp proposed in Patent Document 1. In the heat dissipation structure shown in the figure, a duct 103 is provided along a housing 102 of a vehicle lamp 101 such as a headlamp. A configuration is adopted in which a heat exchanging part 105 such as a heat sink for dissipating heat generated by the LED 104 as a light source is disposed in the duct 103.

  In such a heat dissipation structure, the heat generated by the LED 104 when the vehicular lamp 101 is turned on is generated in the process in which the traveling wind generated by the traveling of the vehicle flows into the air intake 103a of the duct 103 and is discharged from the air outlet 103b. Since heat is dissipated by heat exchange with the traveling wind in the exchanging unit 105, the LED 104 is cooled to prevent the light emission efficiency and the life from being lowered.

  However, in the above heat dissipation structure, when the traveling wind does not flow through the duct 103 because the vehicle is stopped, the heat exchanging unit 105 cannot exhibit the heat exchanging function, and the engine room 106 Since hot air flows back into the duct 103 from the exhaust port 103b and heats the heat exchange unit 105, there is a problem that the LED 104 cannot be effectively cooled.

  Therefore, Patent Document 2 proposes a heat dissipation structure shown in FIG.

  8 is a longitudinal sectional view showing a heat dissipation structure for a vehicle lamp proposed in Patent Document 2. In the heat dissipation structure shown in the figure, a duct 203 is provided along a housing 202 of a vehicle lamp 201 such as a headlamp. A heat sink 205 for dissipating heat generated by the two upper and lower LEDs 204 that are light sources is disposed in the duct 203, and each LED 204 and the heat sink 205 are connected by a heat conducting unit 206. In addition to the intake port 203a and the exhaust port 203b, a forced exhaust port 203c is opened in the duct 203, and an exhaust fan 207 as an exhaust means is disposed in the vicinity of the forced exhaust port 203c.

  Further, the exhaust port 203b of the duct 203 is provided with an opening / closing part 208 for opening and closing the exhaust port 203b, and this opening / closing part 208 is connected to the rod 209a of the cylinder 209. A control unit 210 is connected to the cylinder 209 and the exhaust fan 207, and a vehicle speed sensor 211 that detects the speed of the vehicle on which the vehicle lamp 201 is mounted is connected to the control unit 210.

  In such a heat dissipation structure, the flow rate of the air flowing through the duct 203 is calculated based on the vehicle speed detected by the vehicle speed sensor 211, and when this flow rate is slower than the fan average flow rate, the control unit 210 causes the cylinder 209 to Is driven to close the exhaust port 203b of the duct 203 as shown in the figure, and the exhaust fan 207 is driven to take in air from the intake port 203a of the duct 203 and draw air from the forced exhaust port 203c. By forcibly discharging, an air flow is induced in the duct 203.

  Therefore, even when the vehicle speed is low or the vehicle is stopped, the air flow is generated in the duct 203, so that the heat dissipation of the heat sink 205 is promoted, and the heat sink 205 is connected to the heat sink 205 via the heat conducting portion 206. Each connected LED 204 is cooled and the temperature rise is suppressed.

JP 2008-226843 A JP 2006-286395 A

  However, in the heat dissipation structure for a vehicular lamp proposed in Patent Document 2 shown in FIG. 8, the exhaust fan 207 installed in the severe environment of the engine room has high heat resistance, waterproofness, dustproofness, and vibration resistance. The control system for controlling the driving of the opening / closing unit 208 and the exhaust fan 207 in accordance with the vehicle speed (the flow rate of the air in the duct 203) is complicated, resulting in a significant increase in cost. There is.

  In addition, when the exhaust fan 207 fails, there is a problem that the cooling performance when the vehicle is traveling at low speed and when the vehicle is stopped is insufficient, and the temperature of the LED 204 is increased.

  The present invention has been made in view of the above problems, and the object of the present invention is to provide a vehicular lamp that can secure a required heat radiation performance and suppress an increase in the temperature of a light source with a simple configuration even when the vehicle is stopped. It is to provide a heat dissipation structure.

  In order to achieve the above object, an invention according to claim 1 is a heat dissipation structure for a vehicular lamp including a light source and a heat radiator that dissipates heat generated by the light source, and an air intake portion having one end opened as an air intake port. The radiator is installed in the heat dissipating part of the duct having a heat dissipating part extending in the vertical direction and an exhaust part having one end opened as an exhaust port, and flows into the duct from the intake port and is discharged from the exhaust port. In the heat dissipation structure for a vehicle lamp that cools the light source by promoting heat dissipation of the heatsink by using the air, a difference is provided in the heat insulating properties of the air intake portion of the duct, the heat dissipation portion, and the wall surface of the exhaust portion. It is characterized by.

  The invention according to claim 2 is the invention according to claim 1, wherein the exhaust part of the duct is disposed across the engine room side and the front grille side of the vehicle, and the air intake part and the wall surface of the heat radiating part of the duct are arranged. The heat insulation of the part located on the engine grill side of the exhaust part is set low, and the heat insulation of the wall part of the part located on the front grill side of the exhaust part is set high. It is characterized by.

  According to a third aspect of the present invention, in the first aspect of the invention, the duct is disposed on the front grille side of the vehicle, the heat insulating property of the wall surface of the air intake portion of the duct is set high, and the wall surface of the heat radiating portion is The heat insulating property is set low, and the heat insulating property of the wall surface of the exhaust part is set high.

  According to a fourth aspect of the present invention, there is provided a heat dissipation structure provided in a vehicle having a low engine room temperature in the first aspect of the invention, wherein the heat insulation of the wall surface of the air intake portion of the duct is set high, and the heat dissipation The heat insulation of the wall surface of the part is set low, and the heat insulation of the wall surface of the exhaust part is set high.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, characterized in that the exhaust port of the duct is opened between a front grille of a vehicle engine room, a condenser and a radiator. To do.

According to invention of Claims 1-4, since the heat insulation of the inlet part of a duct, the heat radiating part, and the wall surface of an exhaust part was provided, the average air temperature of the exhaust part of a duct, and the air temperature around an exhaust port, It is possible to increase the intake speed in the duct by increasing the difference between the two. For this reason, the convective heat transfer coefficient of the radiator is increased to improve the heat dissipation performance, and the temperature of the light source is kept low by the heat dissipation from the radiator, thereby preventing the light emission efficiency and the lifetime from being lowered. And since such an effect is acquired by simple structure, without requiring apparatus, such as a fan, according to invention of Claim 5, it does not cause a significant cost increase and the complexity of a structure. The exhaust vent of the duct was opened between the front grille in the engine room and the condenser and the radiator, where the temperature was relatively low even when the engine was stopped and the hot air did not wrap around the front of the vehicle. No flow back into the duct. For this reason, the heat dissipation performance of the radiator is not hindered by hot air, and the heat dissipation of the radiator is promoted by natural air cooling, and the temperature rise of the light source is effectively suppressed.

It is a half cut front view of a vehicle. It is a perspective view which shows the thermal radiation structure of the vehicle lamp which concerns on Embodiment 1 of this invention. It is a plane sectional view which shows the heat dissipation structure of the vehicle lamp which concerns on Embodiment 1 of this invention. It is a front view which shows the thermal radiation structure of the vehicle lamp which concerns on Embodiment 1 of this invention. It is a front view which shows the thermal radiation structure of the vehicle lamp which concerns on Embodiment 2 of this invention. It is a front view which shows the thermal radiation structure of the vehicle lamp which concerns on Embodiment 3 of this invention. It is a longitudinal cross-sectional view which shows the thermal radiation structure of the vehicle lamp proposed in patent document 1. It is a longitudinal cross-sectional view which shows the thermal radiation structure of the vehicle lamp proposed in patent document 2.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a half-cut front view of a vehicle, and a vehicle lamp 1 (only the left one is shown in FIG. 1) used as a headlamp is arranged on the front left and right of the illustrated vehicle 20. A louver-shaped front grille 21 for taking outside air (running wind) into an unillustrated engine room is disposed at the center of the front surface of the vehicular lamp 1, and a front bumper 22 is disposed below the front grille 21. Are arranged horizontally in the vehicle width direction. In FIG. 1, reference numeral 23 denotes a hood that covers the upper part of the engine room, 24 denotes a windshield, 25 denotes left and right front wheels (only one is shown in FIG. 1), and 26 denotes left and right side mirrors.

  Here, although not shown in the figure, an engine is mounted in the engine room of the vehicle 20, and a condenser of an air conditioner, a radiator, and a radiator fan are sequentially arranged in front of the engine from the front. A front grille 21 is disposed, and the left and right vehicle lamps 1 are disposed.

  By the way, when the outside air temperature is 40 ° C. when the vehicle 20 is stopped, the temperature in the engine room is about 70 ° C. to 100 ° C. The hot air generated by the heat generated by the engine and the driving of the radiator fan is discharged from the engine room mainly through the bottom of the vehicle body and the vicinity of the tire house to the outside of the vehicle.

  Next, an embodiment of a heat dissipation structure for the vehicular lamp 1 according to the present invention will be described.

<Embodiment 1>
2 is a perspective view showing the heat dissipation structure of the vehicular lamp according to Embodiment 1 of the present invention, FIG. 3 is a plan sectional view showing the heat dissipation structure, and FIG. 4 is a front view showing the heat dissipation structure. In the following, the heat dissipation structure of one (left side) vehicular lamp 1 is shown and described, but the heat dissipation structure of the other (right side) vehicular lamp is the same, so the illustration and description thereof are omitted. To do.

  As shown in FIG. 3, a vehicular lamp 1 used as a headlamp is juxtaposed in the left-right direction in a lamp chamber 4 defined by a housing 2 and a transparent outer lens 3 covering the front opening thereof. It comprises three lamp modules 5, three semiconductor light emitting elements 6 as light sources, extensions 7, and the like. Here, the three semiconductor light emitting elements 6 are arranged at appropriate intervals along the vehicle front-rear direction (vertical direction in FIG. 3) on the vehicle inner side (right side in FIG. 3) of the housing 2. Are connected to each lamp module 5 via a transmission fiber 8. Each lamp module 5 includes a phosphor 9 and a lens 10 for light distribution control. When the vehicular lamp 1 used as a headlamp emits white light, a blue LED is used for each semiconductor element 6 and a yellow phosphor is used for each phosphor 9.

  By the way, as shown in FIGS. 2-4, the heat sink 11 as a heat radiator arrange | positioned on the exterior of the housing 2 is incorporated in the side wall inside the vehicle of the housing 2. As shown in FIG. 3, the heat sink 11 is composed of a flat base 11a incorporated in the side wall of the housing 2 and a plurality of heat radiation fins 11b erected vertically from the base 11a toward the inside of the vehicle. Has been. Here, as shown in FIG. 5, the plurality of radiation fins 11b are thin plate-like members that are long in the vertical direction, and these are arranged at appropriate intervals along the vehicle longitudinal direction (the vertical direction in FIG. 3). The heat sink 11 is made of an aluminum alloy or magnesium alloy having high thermal conductivity.

  Here, as shown in FIG. 3, a total of three substrates 12 on which the respective semiconductor light emitting elements 6 are mounted are attached to a flat heat radiation base 13 having a high thermal conductivity. It is attached in close contact with the base 11a.

  In the engine room of the vehicle 20, a duct 14 that bends in a U-shape when viewed from the front is disposed. The duct 14 includes a substantially horizontal intake portion 14A and a housing 2 as shown in FIG. The heat dissipating part 14B stands up vertically along the inner wall of the air bag and the exhaust part 14C extends obliquely upward from the heat dissipating part 14B toward the vehicle inner side (right side in FIG. 4).

  Here, as shown in FIG. 1, one end of the intake portion 14A of the duct 14 opens to the front surface of the vehicle 20 (a part of the front grille 21) as an intake port 14a, and one end (upper end) of the exhaust portion 14C. Is opened as an exhaust port 14b between a front grille in an engine room (not shown), a condenser and a radiator. The heat sink 11 is provided in the heat dissipating part 14 </ b> B standing upright in the duct 14.

  Incidentally, in the present embodiment, as shown in FIG. 4, the intake portion 14 </ b> A and the exhaust portion 14 </ b> B of the duct 14 are disposed across the engine room side and the front grille side of the vehicle 20. A difference is provided in the heat insulation of each wall surface of 14A, the thermal radiation part 14B, and the exhaust part 14C. Specifically, the heat insulating properties of the wall surfaces of the intake portion 14A and the heat radiating portion 14B of the duct 14 are set higher than before, and the heat insulating properties of the wall portions of the exhaust portion 14C located on the engine room side are set lower than before. And the heat insulation of the wall surface of the site | part located in the front grille side of the exhaust part 14C is set higher than before. Incidentally, the heat insulation of the wall surface of the conventional duct was set to be constant regardless of the portion.

  Here, the duct 14 is made of a resin such as polypropylene (PP) like the housing 2, but as a method of changing the heat insulating property of the wall surface, a method of changing the thickness or material of the duct 14, A method of applying a surface treatment to the wall surface, adding another member, a method of changing the configuration of the duct 14, or the like can be considered.

  Specifically, in the method of changing the thickness of the duct 14, the heat insulation performance increases as the thickness of the duct 14 increases, and the heat insulation performance decreases as the thickness decreases. In the method of changing the material of the duct 14, for example, a heat conductive material such as a metal or a metal oxide is combined with a resin to use a heat conductive resin having a high thermal conductivity, or a part of the duct 14 is made of metal. It is made up of materials to reduce heat insulation.

  The duct 14 transfers heat by convection and radiation from a high-temperature environment of the engine room. However, since the heat insulation property can be changed by the emissivity of the surface of the duct 14, the duct 14 is heat-insulated by performing a surface treatment. In the method of changing the property, the heat insulating property can be improved by applying a low emissivity material using a ceramic material or the like to the surface. In addition, by applying a material having a high emissivity such as black body paint to the surface of the duct 14, the heat insulation is lowered, or the heat insulation of the duct 14 is increased by using a heat shielding paint such as a heat exchange paint. May be.

  Furthermore, in the method of changing the heat insulation by adding another member to the duct 14, a method of increasing the heat insulation by attaching a heat insulation member such as a glass fiber tape to the surface of the duct 14 is conceivable. In the method of changing the heat resistance, a method of increasing the heat insulation by conceiving the duct 14 as a double structure and sandwiching an air layer therebetween can be considered.

  Thus, in the present embodiment, the heat dissipation structure is configured by the heat sink 11, the heat dissipation base 13 and the duct 14. However, when the vehicle 20 travels at night, a current is supplied to each semiconductor light emitting element 4 of the vehicular lamp 1. When each is supplied, each semiconductor light emitting element 6 emits light, and the blue light is transmitted to each lamp module 5 through each transmission fiber 8 and passes through the yellow phosphor 9 to become white light. Converted. Since the white light passes through the lens 10 and the light distribution is controlled, and then passes through the transparent outer lens 3 and is irradiated to the front of the vehicle 20, the vehicular lamp 1 functions as a headlamp. Fulfill.

  When each semiconductor light emitting element 6 emits light as described above, each semiconductor light emitting element 6 generates heat. The heat is conducted to the heat sink 11 through the substrate 12 and the heat radiating base 13, and a plurality of heat sinks 11 are provided. The heat is radiated from the single heat radiation fin 11b. When the vehicle 20 is traveling, traveling wind flows into the duct 14 from the intake port 14a of the duct 14 and is drawn by the negative pressure generated by the operation of the radiator fan toward the exhaust port 14b. In the process, the air promotes heat dissipation of the heat sink 11 by heat exchange with the heat sink 11 provided in the heat radiating portion 14B of the duct 14, so that each semiconductor light emitting element 6 is forcibly cooled. The temperature rise is suppressed, and the light emission efficiency and life of each semiconductor light emitting element 6 are prevented from being lowered.

  Further, when the vehicle 20 is stopped, the air around the heat sink 11 having a high temperature provided in the heat radiating portion 14B of the duct 14 is heated and the density of the air is reduced. Ascending air flow is induced, and this air flow induces the outside air having a low temperature to be sucked into the duct 14 from the intake port 14a and discharged from the exhaust port 14b. The same air flow is generated as when traveling. And since the heat dissipation of the heat sink 11 is accelerated | stimulated by the natural air cooling by the air which flows through the inside of the duct 14, the temperature rise of each semiconductor light-emitting element 6 is suppressed.

  Further, when the radiator fan is operated when the vehicle 20 is stopped, the air flows in the duct 14 toward the exhaust port 14b due to the negative pressure generated by the operation of the radiator fan. Heat dissipation of the heat sink 11 is promoted by heat exchange with the heat sink 11 provided in the heat dissipation portion 14B of the duct 14.

  Here, in the present embodiment, as described above, the heat insulating properties of the wall surfaces of the intake portion 14A and the heat radiating portion 14B of the duct 14 are set higher than the conventional one, and the wall surface of the portion located on the engine room side of the exhaust portion 14C is set. The heat insulating property is set lower than before, and the heat insulating property of the wall surface of the portion located on the front grill side of the exhaust portion 14C is set higher than before.

  Thus, as described above, when the heat insulating properties of the wall surfaces of the air intake portion 14A and the heat radiating portion 14B of the duct 14 are set higher than those of the conventional art, the low-temperature outside air flowing into the duct 14 from the air intake port 14a. Since the temperature rise is suppressed, the heat sink 11 is cooled by air having a low temperature, and the heat dissipation performance is enhanced.

  By the way, the performance of the duct 14 is represented by an intake speed Q expressed by the following equation. The larger the intake speed Q, the higher the convective heat transfer coefficient of the heat sink 11 and the higher the heat dissipation performance.

ここに、Ｑ：吸気速度［ｍ^３／ｓ］
Ａ：通路断面積［ｍ^２］
Ｃ：流量係数［−］
ｇ：重力加速度［ｍ／ｓ^２］
ｈ：排気部高さ［ｍ］
Ｔex：排気部平均温度［Ｋ］
Ｔout：排気口付近温度［Ｋ］
上式[数１]においてダクト１４の通路断面積Ａ、流量係数Ｃ、排気部高さｈ及び排気口付近温度Ｔoutは一定であり、排気部平均温度Ｔexのみが変数となるため、吸気速度Ｑを上げるためには排気部平均温度Ｔexを高く設定する必要がある。

Where, Q: intake speed [m ³ / s]
A: Passage cross-sectional area [m ² ]
C: Flow coefficient [−]
g: Gravity acceleration [m / s ² ]
h: Exhaust height [m]
Tex: exhaust section average temperature [K]
Tout: Temperature near the exhaust port [K]
In the above equation [Equation 1], the passage cross-sectional area A, the flow coefficient C, the exhaust part height h, and the exhaust port vicinity temperature Tout are constant, and only the exhaust part average temperature Tex is a variable. In order to increase the exhaust temperature, it is necessary to set the exhaust section average temperature Tex high.

  Thus, in the present embodiment, since the heat insulation of the wall surface of the part located on the engine room side of the exhaust portion 14C of the duct 14 is set lower than the conventional one, the air flowing through this part is heated by the heat of the engine room. It becomes easy and the exhaust part average temperature Tex becomes high. For this reason, the intake speed Q is increased from the previous equation [Equation 1], and the heat dissipation performance is improved. In this case, since the heat insulation of the wall surface of the portion located on the front grill side of the exhaust portion 14C of the duct 14 is set higher than the conventional one, the air heated in the exhaust portion 14C is caused by the low temperature air on the front grill side. The exhaust part average temperature Tex is not lowered by being cooled.

  In the present embodiment, even when the vehicle 20 is stopped, the duct 14 is provided between the front grill 21 in the engine room where the temperature is relatively low and the hot air does not wrap around the front of the vehicle 20, and the condenser and the radiator. Since the exhaust port 14b is opened, hot air does not flow from the exhaust port 14b of the duct 14 and flow backward in the duct 14. For this reason, the heat dissipation performance of the heat sink 11 is not hindered by hot air, and the heat dissipation of the heat sink 11 is promoted by natural air cooling, and the temperature rise of each semiconductor light emitting element 6 is effectively suppressed.

  Thus, since the above effects can be obtained with a simple configuration without requiring a separate device such as a fan, the cost of the heat dissipation structure is not significantly increased and the structure is not complicated.

  In the present embodiment, the air inlet 14a of the duct 14 is opened on the front surface of the vehicle 20 (a part of the front grille 21). However, the opening position of the air inlet 14a is arbitrary, and the air inlet 14a is on the front surface of the vehicle 20. May not be opened, but may be opened forward or downward at the lower front end in the engine room.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIG.

  FIG. 5 is a front view showing a heat dissipation structure for a vehicular lamp according to a second embodiment of the present invention. In FIG. 5, the same elements as those shown in FIG. The re-explanation about them is omitted.

  In the present embodiment, the duct 14 is arranged on the front grille side of the vehicle 20, the heat insulation of the wall surface of the intake portion 14A of the duct 14 is set high, the heat insulation of the wall surface of the heat radiating portion 14B is set low, and the exhaust is exhausted. The heat insulating property of the wall surface of the part 14C is set high, and the other configuration is the same as that of the first embodiment.

  Thus, according to the present embodiment, since the heat insulating property of the wall surface of the intake portion 14A of the duct 14 is set higher than before, the temperature rise of the outside air having a low temperature flowing into the duct 14 from the intake port 14a is increased. Therefore, since the heat sink 11 is cooled by air having a low temperature, the heat dissipation performance of the heat sink 11 is improved.

  And since the heat insulation of the wall surface of the heat radiating part 14B of the duct 14 is set low, the heat sink 11 installed in the heat radiating part 14B is cooled by the air on the front grill side having a low temperature, and the heat radiating property of the heat sink 11 is enhanced. . Further, since the heat insulating property of the wall surface of the exhaust portion 14C of the duct 14 is set high, the heat of the air flowing through the exhaust portion 14C does not escape to the front grill side where the temperature is low, and accordingly, the exhaust portion average temperature Tex of the duct 14 Is kept high, and the difference (Tex−Tout) from the exhaust port vicinity temperature Tout increases, so that the intake speed Q obtained by the above equation [Equation 1] increases and the heat dissipation of the heat sink 11 is enhanced.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described below with reference to FIG.

  FIG. 6 is a front view showing a heat dissipation structure for a vehicle lamp according to Embodiment 3 of the present invention. In FIG. 6, the same elements as those shown in FIG. The re-explanation about them is omitted.

  The heat dissipation structure according to the present embodiment is applied to a vehicle such as an electric vehicle having a low engine room temperature. The air intake portion 14A and the exhaust portion 14C of the duct 14 are connected to the engine room side and the front grille side. And the heat dissipating part 14C is arranged on the engine room side. And the heat insulation of the wall surface of the intake part 14A of the duct 14 is set high, the heat insulation of the wall surface of the heat radiating part 14B is set low, and the heat insulation of the wall surface of the exhaust part 14C is set high. The configuration is the same as that of the first embodiment.

  Thus, according to the present embodiment, as in the first and second embodiments, since the heat insulating property of the wall surface of the intake portion 14A of the duct 14 is set higher than the conventional one, the intake port 14a enters the duct 14 from the intake port 14a. An increase in the temperature of the outside air flowing in is suppressed, and the heat sink 11 is cooled by air having a low temperature, so that the heat dissipation performance of the heat sink 11 is improved.

  And since the heat insulation of the wall surface of the heat radiating part 14B of the duct 14 is set low, the heat sink 11 installed in the heat radiating part 14B is cooled by the air at the low engine room side, and the heat radiating property of the heat sink 11 is enhanced. It is done. Further, since the heat insulation of the wall surface of the exhaust part 14C of the duct 14 is set high, the heat of the air flowing through the exhaust part 14C does not escape to the engine room side or the front grille side where the temperature is low. The average temperature Tex is kept high, and the difference (Tex−Tout) from the exhaust port vicinity temperature Tout increases, so the intake speed Q obtained by the above equation [Equation 1] increases and the heat dissipation of the heat sink 11 increases. It is done.

  In the above embodiment, the heat sink has a fin shape with a plate type. However, a pin type other than the plate type, a sword mountain shape, a bellows shape or the like having any fin shape should be used. Can do.

  Further, in the above embodiment, a semiconductor light emitting element that is a heat source and a lamp module connected via a transmission fiber is used. However, the semiconductor light emitting element and the lamp module are integrated into a heat pipe or the like. It is also possible to use a structure that is thermally connected to the heat sink base using a transportation means. Further, because of the aiming adjustment mechanism, the heat sink may be connected to the housing via a rubber gasket or the like so that the heat sink can move within a certain range.

  Further, although the above description has been given of a mode in which the present invention is applied to a heat dissipation structure for a vehicular lamp used as a headlamp, the present invention is limited to a gasoline vehicle equipped with an engine as vehicle driving energy. Needless to say, the present invention can be applied to a vehicle using electricity, hydrogen fuel, or the like, and can be similarly applied to a heat dissipation structure of any vehicle lamp other than the headlamp. Moreover, in this Embodiment, although blue LED was used as a semiconductor light-emitting device, other semiconductor light-emitting devices, such as LED other than blue LED, and a laser, can be used as a light source.

DESCRIPTION OF SYMBOLS 1 Vehicle lamp 2 Housing 3 Outer lens 4 Lamp chamber 5 Lamp module 6 Semiconductor light emitting element (light source)
7 Extension 8 Transmission fiber 9 Phosphor 10 Lens 11 Heat sink (heatsink)
11a Heat sink base 11b Heat sink fin 12 Substrate 13 Radiation base 14 Duct 14A Duct air intake 14B Duct heat sink (vertical part)
14C Duct Exhaust Portion 14a Duct Inlet Port 14b Duct Exhaust Port 20 Vehicle 21 Front Grill 22 Front Bumper 23 Bonnet 24 Windshield 25 Front Wheel h Duct Exhaust Height 26 Side Mirror Tex: Average Air Temperature Tout: Duct Exhaust Portion Tout : Temperature near the exhaust port of the duct

Claims (5)

A heat dissipation structure for a vehicular lamp including a light source and a heat radiator that dissipates heat generated by the light source, wherein an intake portion having one end opened as an intake port, a heat release portion extending in the vertical direction, and one end opened as an exhaust port The heat radiator is installed in the heat radiating portion of a duct including an exhaust portion, and heat radiation of the heat radiator is promoted by air that flows into the duct from the air inlet and is exhausted from the air outlet. In the heat dissipation structure of the vehicular lamp to be cooled,
A heat dissipating structure for a vehicular lamp, characterized in that a difference is provided in the heat insulating properties of the wall surfaces of the air intake part, the heat dissipating part and the exhaust part of the duct.   The exhaust part of the duct is disposed across the engine room side and the front grille side of the vehicle, and the heat insulation of the wall of the intake part and the heat radiating part of the duct is set high, on the engine room side of the exhaust part 2. The heat dissipation structure for a vehicular lamp according to claim 1, wherein the heat insulating property of the wall surface of the portion located is set low, and the heat insulating property of the wall surface of the portion located on the front grill side of the exhaust part is set high.   The duct is disposed on the front grille side of the vehicle, the heat insulating property of the wall surface of the air intake part of the duct is set high, the heat insulating property of the wall surface of the heat radiating part is set low, and the heat insulating property of the wall surface of the exhaust part is set. 2. The heat dissipation structure for a vehicular lamp according to claim 1, wherein the heat dissipation structure is set high.   A heat dissipating structure provided in a vehicle having a low engine room temperature, wherein heat insulation of the wall surface of the air intake part of the duct is set high, heat insulation of the wall surface of the heat dissipating part is set low, and the wall surface of the exhaust part The heat dissipation structure for a vehicular lamp according to claim 1, wherein the heat insulating property of the lamp is set high. The heat dissipation structure for a vehicular lamp according to any one of claims 1 to 4, wherein an exhaust port of the duct is opened between a front grill of a vehicle engine room, a condenser, and a radiator.

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