JP2009266573A - Lamp tool for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent temperature rise of a lamp unit using LEDs, even if heat dissipation capacity of a heat sink is temporarily decreased. <P>SOLUTION: A lamp unit 17 with light-emitting diodes 19 as a light source is mounted on a thermally conductive base material 18, and a lamp room 14 housing the lamp unit 17 is structured of a housing 12. At least part of the heat sink 26 is arranged outside the housing 12, and running wind is blown at the heat sink 26 through a ventilating channel 27 at running of a vehicle. Further, phase changing materials 281, 282 are provided in a state in contact with the base material 18 and the heat sink 26 for easing temperature changes outside. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicular lamp equipped with a lamp unit using LEDs.

A vehicular lamp using a conventional LED has a heat radiation portion of the LED lamp unit provided in the air passage. The part equipped with the vehicle lamp is provided with an intake port for taking in the running wind during driving and an exhaust port for discharging the air flowing through the ventilation path, and a heat radiating part is located between the intake port and the exhaust port I am letting. As a result, outside air is introduced from the suction port into the ventilation path while the vehicle is running, and the heat generated by the LEDs is dissipated by the air flowing through the ventilation path from the heat radiating section and is discharged outside the vehicle. (For example, Patent Document 1)
JP 2006-286395 A

  In the technique of Patent Document 1 described above, when the vehicle stops due to a red signal or the like, air is not introduced into the ventilation path, the heat dissipation capability of the heat sink decreases, and the temperature of the LED temporarily rises. Due to this temperature rise, there has been a problem that the light amount of the LED is decreased, the chromaticity is changed, and the excessive temperature rise also causes the failure of the LED itself or shortens its life.

  An object of the present invention is to provide a vehicular lamp that can suppress an increase in the temperature of an LED even when the heat dissipation capability of a heat sink is temporarily reduced.

  In order to solve the above-described problems, a vehicular lamp according to the present invention includes a thermally conductive base material to which a lamp unit having a light emitting element as a light source is attached, a lamp chamber that houses the lamp unit, and the lamp chamber. A heat sink disposed at least partly outside the housing, a ventilation path that applies running air to the heat sink during traveling, and an external device attached in contact with the base material and the heat sink. And a heat storage member for relaxing temperature change.

  According to this invention, even when the heat dissipation capability of the heat sink of the lamp unit is temporarily reduced, the temperature rise of the LED can be suppressed.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

1 to 4 are diagrams for explaining one embodiment of the vehicular lamp according to the present invention. FIG. 1 is a cross-sectional view, FIG. 2 is a cross-sectional view taken along line II 'in FIG. 1, and FIG. 'A cross-sectional view showing only the main part, FIG. 4 is an explanatory view for explaining the effect of this embodiment.
1 and 2, reference numeral 11 denotes a headlamp, and the headlamp 11 has a housing 12 made of, for example, a resin injection molded product. An outer lens 13 made of, for example, a transparent resin molded product is watertightly attached to the front opening 121 of the housing 12, and a lamp chamber 14 is formed between the housing 12 and the outer lens 13. .

  A work opening 122 communicating with the inside of the lamp chamber 14 is opened at the rear of the housing 12, and the work opening 122 is closed by the back cover 15. Specifically, an inward flange 123 is provided in the vicinity of the work opening 122 inside the housing 12. On the other hand, a claw portion 151 that is detachably engaged with the inward flange 123 is provided on the edge portion of the back cover 15. The back cover 15 is held by the housing 12 by the claw portions 151 being locked to the inward flange 123. At this time, for example, the seal ring 16 is interposed between the inward flange 123 and the back cover 15, so that the back cover 15 closes the work opening 122 in a watertight manner.

  Here, the housing 12 and the back cover 15 may be made of a metal material such as aluminum, but are made of a heat-resistant synthetic resin rich in workability.

  A lamp unit 17 is disposed inside the lamp chamber 14. The lamp unit 17 includes, for example, a base 18 having a substantially rectangular shape in plan view and high heat conductivity. A plurality of light emitting diodes (LEDs) 19 that are light emitting elements are attached as light sources on the surface of the substrate 18 facing the outer lens 13. In this embodiment, each LED 19 is configured by a plane-mounting type LED chip in which a single convex lens 20 is fixed on an emission plane.

  Further, a cylindrical member 21 surrounding the periphery of each LED 19 is fixed to the base material 18, and a projection lens 22 held at the tip of the cylindrical member 21 is opposed to the emission plane of the LED 19. In addition, in order to obtain a light beam having a desired shape by the light emitted from each LED 19, it is possible to arrange a light shielding mask or the like that cuts off the incidence of light on a predetermined area on the incident side of each projection lens 22. The base material 18 is fixed to the back cover 15 via, for example, a mounting means 23 using nuts and screws.

  Here, an inner panel 25 is interposed between the outer lens 13 and the lamp unit 17 for the purpose of improving the appearance design. The inner panel 25 is provided with a cylindrical opening 251 at a position corresponding to each LED 19, and each projection lens 22 loosely inserted into the cylindrical opening 251 faces the outer lens 13.

  Further, on the surface of the base material 18 opposite to the surface on which the LED 19 is mounted, a heat sink 26 and a heat sink 26 integrally formed with heat dissipation fins 261 made of, for example, aluminum having high thermal conductivity for dissipating heat generated by the LED 19 are provided. Surface bonded. The heat radiating fins 261 are arranged so as to protrude from the back cover 15.

  A ventilation path 27 is formed on the outer surface side of the back cover 15. The ventilation path 27 is provided with an inlet 271 for taking in the traveling wind in the direction of the arrow Wi during traveling of the vehicle and an exhaust outlet 272 for discharging the air flowing in the ventilation path 27 in the direction of the arrow Wo.

  As shown in FIG. 3, 281 and 282 are a kind of heat storage members that are attached to the upper and lower sides of the heat sink 26 on the base 18 side using, for example, an adhesive and arranged in contact with the base 18. It is a phase change material and is also called PCM = Phase Change Material. The phase change materials 281 and 282 are temperature adjustment materials for relaxing temperature changes in the external environment.

  Examples of the phase change materials 281 and 282 include sodium thiosulfate hydrate having a melting point of 48 ° C., sodium acetate hydrate having a melting point of 58 ° C., n-tetradecane having a melting point of 5 ° C., and n-octadecane having a melting point of 28 ° C. An appropriate material may be selected depending on the temperature to be suppressed. An additive may be added to adjust the melting point.

  Furthermore, the phase change material changes its state according to the phase change due to the solid, gel, liquid, and temperature, and the volume changes accordingly, so it is enclosed in a container. The container is made of, for example, aluminum having good thermal conductivity, and the amount of the phase change material to be enclosed needs to be set to such an extent that the container is not damaged by the phase change. For example, it is preferable to provide a flat surface on at least one surface of the container so that the container can be attached in close contact with the substrate 18. It is also effective to use pellets, slurries, sheets and the like formed using microcapsules in which a phase change material is encapsulated in a water-insoluble resin film.

  Consider the case where the vehicle is running. While the vehicle is running, outside air is introduced into the ventilation path 27 from the suction port 271, and the air in the ventilation path 271 is discharged from the exhaust port 272. During this time, the heat generated in the LED 19 is radiated from the heat sink 26 by the air flowing in the ventilation path 27, and the temperature rise of the LED 19 can be suppressed.

  Next, when the vehicle is stopped, the phase change materials 281 and 282 absorb heat and change the phase from the solid phase to the gel and liquid phase to store heat, so that the temperature rise of the LED 19 can be suppressed. The heat stored in the phase change materials 281 and 282 is dissipated from the heat sink 26 by the air flowing in the ventilation path 27 when the vehicle travels, and the phase change materials 281 and 282 return from the liquid phase to the gel and solid phase.

  FIG. 4 shows the temperature change of the base material 18 at the point P indicated by the arrow in FIG. 1 after the vehicle stops. When the vehicle stops at a position of 0.0 minutes on the time axis, the temperature at the point P becomes a characteristic of a broken line when the phase change materials 281 and 282 are not present, but when the phase change material 28 is present. Although it rises slightly, it maintains a constant temperature for the subsequent t period. This is because the phase change materials 281 and 282 make use of the characteristics that have a time difference with respect to temperature changes in the external environment.

  As a result, when the heat dissipation capability of the heat sink 26 temporarily decreases due to a vehicle stoppage or the like, the temperature change of the LED 19 can be suppressed by the action of the phase change materials 281 and 282, and the failure of the LED itself can be prevented and long. It can also contribute to life extension.

  By the way, the arrangement positions of the phase change materials 281 and 282 may be anywhere as long as they are in contact with the base material 18, but the LED 19 to be suppressed from the relationship between the temperature of the LED 19 and the base material temperature of the part where the phase change material 28 is arranged. Grasping the substrate temperature of the part where the phase change material 28 is arranged at a temperature, and arranging the phase change materials 281 and 282 having a melting point equal to or lower than the substrate temperature and a melting point equal to or higher than the substrate temperature at the time of traveling Is preferred.

  FIG. 5 is a cross-sectional view corresponding to FIG. 3 for explaining a modification of the embodiment of the present invention. In this modification, a phase change material 283 formed in a ring shape is inserted into the base 18 side of the heat sink 26 and arranged in contact with the base 18. In this case, the phase change material 283 has a wide contact area between the heat sink 26 and the base material 18, and a large amount of the phase change material 283 can be disposed, so that the relaxation time with respect to the temperature change can be extended.

  6 to 8 are cross-sectional views showing only the main part, and FIG. 7 is a left side of the heat sink in FIG. 6 as viewed from the heat sink side. FIG. 8 is an explanatory view for explaining the effect of this embodiment.

  Here, if a large amount of phase change material is used, the suppression time of the temperature of the LED 19 can be lengthened, but the relationship between the LED temperature to be suppressed and the temperature of the substrate 18 differs depending on the portion of the base material 18 to be arranged. It is preferable to place a phase change material having a suitable melting point. In this embodiment, a plurality of phase change materials are used, and phase change materials having melting points suitable for the parts are arranged.

  In FIG. 6, the cooling parts 411 and 412 are formed by bending the upper and lower surfaces of the base material 18 to which the lamp unit 17 is attached to the heat sink 26 side at substantially right angles. Between the cooling part 411 and the heat sink 26, for example, a phase change material 283 of A having a melting point of 57 ° C. is disposed so as to be in contact with the substrate 18. Similarly, for example, a phase change material 284 having a melting point of 57 ° C. is disposed between the cooling unit 412 and the heat sink 26 so as to be in contact with the base material 18.

  For example, a B phase change material 285 having a melting point of 47 ° C. is disposed between the cooling unit 411 and the heat sink 26 so as to be in contact with the A phase change material 283. Similarly, a phase change material 286 of B having a melting point of 47 ° C. is disposed between the cooling unit 412 and the heat sink 26 so as to be in contact with the phase change material 284 of A, for example.

  Further, the phase change material 287 of B, the phase change material 284 of B, and the phase change material 286 of B are arranged on the opposite surface of the cooling unit 411 on which the phase change material 283 of A and the phase change material 285 of B are arranged. The B phase change material 288 is attached to the opposite surface of the cooled portion 412 using an adhesive.

  The vehicle travels at a temperature indicated by a point P1 indicated by an arrow at 50 ° C. and at a temperature indicated by a point P2 indicated by an arrow at 40 ° C. If the heat dissipation capability of the heat sink 26 temporarily decreases due to a vehicle stop or the like, the temperature to be suppressed at the point P1 is 60 ° C., and the temperature to be suppressed at the point P2 is 50 ° C. The phase change materials 283 and 284 of A to be controlled at the P1 site have a melting point of 57 ° C., and the phase change materials 285 to 288 of B to be controlled at the site of the point P2 are 47 ° C.

  As described above, the temperature increase for a long time can be suppressed by appropriately disposing the phase change material having a melting point that is lower than the temperature to be suppressed and higher than the temperature at the time of traveling at each point.

  FIG. 8 is an explanatory diagram for explaining an effect related to another embodiment of the present invention. In FIG. 8, when the heat dissipation capability of the heat sink temporarily decreases due to a vehicle stoppage or the like, the temperature rises with time when the phase change material is not added, but when the phase change material is added, The rise temperature of the part can be suppressed to a desired temperature or less, and as a result, the temperature rise of the LED can be prevented.

  FIG. 9 is a side view corresponding to FIG. 7 for explaining a modified example of another embodiment of the present invention.

  In this modification, a cylindrical cooling part 413 that is continuous with the base material 18 is formed, and a B phase change material 289 formed in a ring shape and a phase change material A (not shown) formed in a ring shape are heat sinks. 26, respectively. Further, a ring-shaped B phase change material 301 is arranged on the outer periphery of the cooling unit 413.

  In this case, since the phase change material has a wider contact area with respect to the heat sink 26 and the base material 18 and can be disposed in a large amount, it is possible to extend the suppression time for the temperature rise.

Sectional drawing for demonstrating one Embodiment regarding the vehicle lamp of this invention. I-I 'sectional drawing of FIG. II-II 'sectional drawing of FIG. Explanatory drawing for demonstrating the effect of one Embodiment of this invention. Sectional drawing equivalent to FIG. 3 for demonstrating the modification regarding one Embodiment of this invention. Sectional drawing of the principal part for demonstrating other embodiment regarding the vehicle lamp of this invention. The left view of FIG. Explanatory drawing for demonstrating the effect of other embodiment of this invention. The side view equivalent to FIG. 5 for demonstrating the modification regarding other embodiment of this invention.

Explanation of symbols

11 Head lamp 12 Housing 14 Lamp chamber 15 Back cover 17 Lamp unit 18 Base material 19 LED
26 Heat sink 261 Radiation fin 27 Ventilation path 281-301 Phase change material 411-413 Cooling part

Claims (3)

A thermally conductive base material to which a lamp unit having a light emitting element as a light source is attached;
A lamp chamber for housing the lamp unit;
A housing constituting the lamp chamber;
A heat sink at least partially disposed outside the housing;
A ventilation path that applies traveling airflow to the heat sink during traveling;
A vehicular lamp, comprising: a heat storage member for relaxing external temperature changes attached in contact with the base material and the heat sink.   The vehicular lamp according to claim 1, wherein the heat storage member is formed of a phase change material whose phase change is between a solid, a gel, and a liquid.   A plurality of the phase change materials having different melting point temperatures are used, and the melting point temperature of the phase change material disposed near the light emitting element is higher than the melting point temperature of the phase change material disposed at a far position. The vehicular lamp according to claim 2.

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