JP5233590B2 - Vehicle headlamp - Google Patents

Description

  The present invention relates to a vehicular headlamp when a semiconductor light emitting element is used as a light source, and particularly focuses on cooling when stopped.

In general, a vehicle headlamp that uses a semiconductor light-emitting element such as a light-emitting diode (LED) as a light source has low luminous efficiency due to temperature rise. For this reason, in lamps using LEDs, measures are taken to prevent temperature rise, and the plate-shaped fins in the horizontal direction are installed in the lamp housing to increase heat dissipation by increasing the surface area of the housing. The temperature rise of the LED is suppressed. (For example, Patent Document 1)
JP 2007-207528 (page 7, FIG. 1)

  The technique of the above-mentioned Patent Document 1 is to integrally form fins on the outer surface of an aluminum die-cast metal lamp body to efficiently dissipate heat generated from the LED. However, since the lamp body is housed in a state of being covered by a housing for mounting on the vehicle side, the fins obstruct the air flow when the vehicle stops simply by forming the fins on the lamp body. There is a problem that the heat dissipation effect is low, the temperature inside the lamp body does not drop, the luminous efficiency is lowered, and the lifetime of the LED is shortened.

  An object of the present invention is to provide a vehicular headlamp that uses a semiconductor light-emitting element with improved heat dissipation effect as a light source by adopting a fin shape that has a heat dissipation effect due to natural convection even when the vehicle stops. It is in.

In order to solve the above-described problems, a vehicle headlamp according to the present invention includes a cylindrical lamp body in which a semiconductor light emitting element is disposed, and at least an opening is formed on the irradiation side of the light emitting element. A plurality of fins formed on the outer peripheral surface of the lamp body in a rotational direction with respect to a horizontal axis, a housing for attaching the lamp body to a vehicle together with the fins, and the fin sandwiching the fins And vents formed on the upper and lower sides of the casing, respectively.

  According to the present invention, even when fins are used for cooling a vehicle headlamp that uses a semiconductor light emitting element as a light source, it is possible to cause smooth natural convection when the vehicle is stopped and to achieve efficient heat dissipation. Become.

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

  FIG. 1 is a conceptual perspective view for explaining an embodiment of a vehicle headlamp according to the present invention, FIG. 2 is a perspective view for explaining members to be attached to the vehicle of FIG. 1, and FIG. FIG. 4 is a side view of FIG. 3, FIG. 5 is a sectional view of FIG. 4, and FIG. 6 is an explanatory diagram for explaining the LED and the projection lens of FIG.

  First, in FIGS. 1 and 2, reference numeral 11 denotes a lamp body having a cylindrical irradiation opening 111 made of, for example, an aluminum alloy having high heat dissipation. A transparent cover 13 made of, for example, glass for irradiation is attached to the opening 111 of the lamp body 11. Reference numeral 14 denotes a housing made of a heat-resistant resin having a bottomed portion 141 for mounting on the vehicle side. The housing 14 includes a holding portion 112 that holds and accommodates the lamp body 11 in a positioned state. Positioning means such as a plurality of ribs (not shown) are integrally formed on the inner peripheral surface of the holding portion 112 in order to hold the lamp body 11 without loosening.

  Ventilation holes 143 and 144 are formed in the bottom surface portion 142 which is the lower side of the housing 14 when attached to the vehicle, and the ventilation holes 146 are formed in the upper surface portion 145 which is the upper side of the housing 14. The air taken in from the vents 143 and 144 can be released from the vent 146. The vent holes 143 and 144 serve as intake air, and the vent holes 146 serve as exhaust air.

  Next, the lamp body 11 will be described with reference to FIGS. FIG. 3 is a perspective view of the lamp body 11, but also shows a partial cross section of the housing 14 as viewed from the vent 146 side in a state of being accommodated in the housing 14.

  A back cover 15 is attached to the opposite side of the cylindrical lamp body 11 to which the transparent cover 13 is attached, and the inside of the lamp body 11 is sealed with the transparent cover 13 and the back cover 15 waterproofed. Is done. A plurality of plate-shaped cooling fins 113 are integrally formed on the outer periphery of the lamp body 11.

  As shown in FIG. 4, the fins 113 are shaped so that they are parallel to the outer periphery of the lamp body 11 and perpendicular to the outer periphery of the lamp body 11 while being mounted on the vehicle. Formed with. Accordingly, the space 114 between the fins 113 is in a state of passing through in the vertical direction indicated by the arrow in FIG. 4 from the lower surface to the upper surface of the lamp body 11. The space 114 forms a duct 16 that extends from the bottom to the top by the inner surface of the housing 14.

  In FIG. 5, at a position facing the transparent cover 13 in the lamp body, a heat-resistant circuit board 19 made of, for example, glass epoxy, in which a plurality of LEDs 17 are linearly arranged and configured as a light source 18 is arranged. . The circuit board 19 is attached to an attachment portion 115 integrally formed in the lamp body 11 by, for example, fixing means such as screws (not shown).

  Further, in the lamp body 11, a circuit board 20 made of, for example, the same material as the circuit board 19 is disposed with a space 116 from the circuit board 19 on the opposite side on which the LEDs 17 are mounted. A drive circuit for driving the light source 18 is configured on the circuit board 20, and although not shown, the circuit board 19 and the circuit board 20 are electrically connected.

  The LED 17 is configured as a package, and the light source 18 is configured by, for example, four LEDs 17. A prism lens 21 that introduces light from the light source 18 and emits it forward is disposed on the irradiation side of the light source 18.

  The prism lens 21 can be applied to a vehicle lamp having an alignment characteristic required as a traveling beam for a vehicle, that is, an alignment pattern that is substantially parallel in the vertical direction and diffuses in the horizontal direction.

  6 and 7 are explanatory views for explaining the prism lens 21 suitable for the alignment pattern of the traveling beam for the vehicle. FIG. 6 is a perspective view, and FIG. 7A shows the prism lens 21 on the exit surface side. 7B and 7C are sectional views taken along lines bb and cc of FIG. 7A.

  The prism lens 21 is provided on a main body 213 having an incident surface 211 and an output surface 212, a light receiving unit 214 provided on the incident surface 211, a direct light incident unit 215 provided on the light receiving unit 214, and an output surface 212. The direct light emitting part 216 and the reflected light emitting part 217 provided on the emission surface 212 are configured to be integrally injection-molded with, for example, a transparent acrylic resin. The main body 213 is set with the length direction as the horizontal axis.

  The direct light incident portion 215 of the light receiving portion 214 has a planar shape, and is formed in a concave portion having a substantially U-shaped cross section along the length direction at the center portion in the width direction of the incident surface 211. In the light receiving portion 214, both side surfaces 214a and 214b also constitute a light incident portion.

  The direct light emitting part 216 is formed as a convex line having a tip surface with a convex cross section along the length direction of the central part of the emitting surface 212, and the reflected light emitting part 217 is a direct light of the emitting surface 212. It is formed on the upper side and the lower side of the emission part 216, respectively.

  Further, the linear light source 18 is configured by assembling four LEDs 17 with their light emitting portions fitted into the light receiving portions 214. That is, the four LEDs 17 are attached to the circuit board 19 at the base end side, and the light emitting part is set to the circuit board 19 with the incident surface 211 facing the main body part set with the length direction as the horizontal axis. 213 is fitted into the light receiving portion 214 and assembled. At this time, each LED 17 is attached in a state in which the light emission center of the light emitting part is substantially matched with the focal position of the parabola that is the outer peripheral shape of the main body part 213.

  In the vehicular lamp 10 configured as described above, the light emitted from the four LEDs 17 is transmitted to the main body 213 via the both side surfaces 214a and 214b of the light receiving unit 214 and the direct light incident unit 215 of the light receiving unit 214. Let it be introduced. The light introduced into the main body part 213 from both side surfaces 214a and 214b of the light receiving part 214 mainly reaches the parabolic outer peripheral surfaces 218a and 218b constituting the upper and lower side surfaces of the main body part 213, respectively. After total reflection at 218a and 218b, the light is emitted outward from the reflected light emitting portion 217. That is, when the reflected light is emitted from the reflected light emitting portion 217, a horizontally-long belt-like light distribution pattern that is long in the length direction of the main body portion 213 is obtained.

  When the vehicle stops, as shown in FIG. 8, it is configured between the fin 113 formed in the vertical direction and the casing 14 from the lower vents 143 and 144 to the upper vent 146. Due to the chimney effect of the duct 16, an air flow by natural convection is generated from the vent holes 143 and 144 to the vent hole 146 as indicated by the wavy arrows x and y. Thereby, the temperature rise of the lamp body 11 when the vehicle is stopped can be suppressed, and as a result, the temperature rise of the internal LEDs 17 and the like can be suppressed.

  As a result of comparison between the present invention and the conventional heat dissipation state between the housing 14 and the fins formed on the lamp body 11, the housing temperature in the vicinity of the LED in the conventional case was about 65 ° C. The housing temperature in the vicinity of the LED became about 55 ° C., and it was confirmed that the temperature rise of the LED in the configuration of the present invention was suppressed.

  In this embodiment, the lamp body 11 attached to the vehicle is formed with plate-shaped cooling fins 113 in the rotational direction with respect to the horizontal axis on the outer peripheral surface of the cylindrical outer shape. The lamp body 11 is configured such that the fins 113 of the lamp body 11 are positioned in the vent holes 143 and 144 and the vent hole 146 of the casing 14 in which the vent holes 143 and 144 and the vent hole 146 of the casing 14 attached to the vehicle side are respectively formed. It is made to accommodate in the housing | casing 14 in the state.

  As a result, even when the vehicle is stopped, the fin 113 can be cooled by the action of natural convection by the duct 16 formed between the space 114 of the fin 113 and the inner surface of the housing 14. As a result, the temperature rise in the lamp body 11 can be suppressed, and the temperature of the LED 17 can be suppressed.

  The present invention is not limited to the above-described embodiment. For example, the back cover 15 attached to the back side of the lamp body 11 may be integrally formed with the lamp body 11. The circuit board 20 in this case may be inserted and attached through the opening 111 like the circuit board 19. Further, although the four light-emitting LEDs 17 are used for the light source 18, it is increased or decreased as necessary.

  Further, although an alloy of aluminum is used for the lamp body 11, a metal other than the aluminum alloy may be used, and ceramics having high thermal conductivity or high emissivity may be used. Although the lamp body 11 has a cylindrical shape, it may have a rectangular parallelepiped structure. If the plate-like fins 7 are formed on at least a part of the outer surface in the rotational direction with respect to the horizontal axis. Good.

The conceptual perspective view for demonstrating one Embodiment regarding the vehicle headlamp of this invention. The perspective view of the principal part of FIG. The perspective view of the principal part of FIG. FIG. 4 is a side view of FIG. 3. Sectional drawing of FIG. The perspective view for demonstrating a prism lens. 6A is a plan view seen from the exit surface side, FIG. 6B is a cross-sectional view taken along the line bb in FIG. 6A, and FIG. Sectional drawing which follows the -c line. Explanatory drawing for demonstrating the effect of this invention.

Explanation of symbols

11 Lamp body 111 Opening 112 Holding portion 113 Fin 114 Space portion 115 Mounting portion 116 Space 13 Transparent cover 14 Housing 141 Bottom 142 Bottom surface portion 143, 144, 146 Vent 145 Upper surface portion 15 Back cover 16 Duct 17 LED
18 Light source 19, 20 Circuit board 21 Prism lens 211 Entrance surface 212 Exit surface

Claims (2)

A cylindrical lamp body in which a semiconductor light emitting element is disposed, and at least an opening is formed on the irradiation side of the light emitting element;
A plurality of fins formed in a rotation direction with respect to a horizontal axis on an outer peripheral surface of the lamp body in a state of being attached to a vehicle;
A housing for attaching the lamp body to the vehicle together with the fins;
Vehicular headlamps comprising vents formed on the upper and lower sides of the casing sandwiching the fins, respectively.   The vehicle headlamp according to claim 1, wherein a duct extending from below to above is formed between the space between the fins and the housing.

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