Motorcycle headlight

Abstract

To provide a motorcycle headlight comprising a novel air cooling structure having an excellent heat dissipation function.SOLUTION: In a motorcycle headlight, a light source unit 105 is arranged in a lighting chamber 103 closed by an outer lens 101 and a housing 102, and light emitted from the light source unit 105 is used for illumination. At least one through hole 108 penetrating the outer lens 101 and the housing 102 in a front-rear direction of a vehicle is formed, and outside air can move in the through hole 108 from a front side to a rear side in association with movement of the vehicle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motorcycle headlamp, and more particularly to a motorcycle headlamp that uses a semiconductor light-emitting element such as a light-emitting diode as a light source and can suppress a decrease in light-emitting efficiency by suppressing a temperature rise of the semiconductor light-emitting element through air cooling. [Background technology]

[0002] A motorcycle headlamp needs to distribute illumination light ahead of the motorcycle as it moves. For this reason, as shown in Fig. 5A, the front surface of the headlamp is made of an outer lens 101 made of a light-transmitting material such as glass. A light source unit 105 including electrical components such as wiring is supported by a housing with excellent mechanical strength.

[0003] As shown in Figure 5B, which is a cross-sectional view of Figure 5A taken along line BB, a transparent outer lens 101 is combined with a housing 102 which is not translucent but has high support function to form a sealed lamp chamber 103, and a light source unit 105 is arranged in the lamp chamber 103.

[0004] Semiconductor light-emitting elements have the characteristic that their light-emitting efficiency decreases with an increase in temperature. When the semiconductor light-emitting element is turned on, the semiconductor light-emitting element generates heat due to its resistance component, and the temperature of the semiconductor light-emitting element increases. The lamp chamber 103 is a closed space, and the air inside the lamp chamber 103 increases in temperature due to the heat generated by the semiconductor light-emitting element, which can cause a decrease in light-emitting efficiency. The outer wall of the lamp chamber 103 is in contact with the outside air and is air-cooled. In order to suppress the decrease in light-emitting efficiency, it is desirable to efficiently cool the air around the semiconductor light-emitting element.

[0005] FIG. 6A shows a front view of a motorcycle equipped with a dual headlamp. The motorcycle headlamp 1 attached to the front cowl 17 has two LED lamps, which are semiconductor light emitting devices, arranged side by side in the horizontal direction. When a drive current is passed through the LED to cause it to emit light, the LED generates heat based on the drive current, causing the temperature of the LED to rise. The LED's light emitting efficiency decreases as the temperature rises, and the amount of light emitted decreases. To prevent a decrease in light emitting efficiency, it is desirable to prevent the temperature rise of the LED.

[0006] 6B, which shows a cross-sectional view taken along line CC of FIG. 6A, light generated from the LED 6 is projected forward via a reflector 9, an optical system 5 including a projection lens 12, and a front lens 2. A configuration has been proposed in which heat generated from the LED 6 is guided from an LED mounting board 7 on which the LED 6 is mounted, via a mount plate 8, to heat dissipation fins 13 arranged outside the lamp chamber, and the heat is removed from the heat dissipation fins 13 by outside air introduced from an outside air intake 14 via an air duct 16, thereby increasing the amount of heat dissipation (see Patent Document 1).

[0007] In this configuration, heat generated from the light source is conducted to the heat dissipation fins 13 by the heat transfer mechanism, raising the temperature of the heat dissipation fins 13, and outside air taken in from the outside air intake 14 cools the heat dissipation fins 13, moving the heat conducted from the light source to the outside air and dissipating it. The outside air flowing through the air supply duct 16 removes heat from the heat dissipation fins 13, preventing the light source from overheating. However, heat travels only by conduction from the LED mounting board 7 to the heat dissipation fins 13 via the mounting plate 8. It can be said that an air-cooling mechanism that removes heat at a position closer to the light source, which is the heat source, is more preferable. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2008-123756 A Summary of the Invention [Problem to be solved by the invention]

[0009] A primary object of the present invention is to provide a motorcycle headlamp having an excellent heat dissipation function by improving the air-cooling structure. [Means for solving the problem]

[0010] According to a main aspect of the present invention, there is provided a motorcycle headlight in which a light source unit is disposed within a lamp chamber sealed by an outer lens and a housing, and light emitted from the light source unit is used for illumination, in which at least one through hole is formed penetrating the outer lens and the housing in the fore-and-aft direction of the vehicle, and outside air can move from the front to the rear within the through hole as the vehicle moves. Effect of the Invention

[0011] A motorcycle headlamp having a novel structure with excellent heat dissipation function is provided. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1A is a front view of a motorcycle headlamp according to an embodiment, and FIG. 1B is a cross-sectional view taken along line AA in the front-rear direction of the motorcycle headlamp shown in FIG. 1A. [Diagram 2] FIG. 2 is an exploded perspective view of the motorcycle headlamp shown in FIG. 1A. [Diagram 3] 3A to 3E are front views of modified motorcycle headlights. [Figure 4] FIG. 4 is a front view of a through hole portion according to a modified example. [Diagram 5] 5A and 5B are a front view and a BB cross-sectional view taken along the front-rear direction of a conventional motorcycle headlamp. [Figure 6] FIG. 6A is a front view of a typical motorcycle according to the prior art, and FIG. 6B is a cross-sectional view showing an example of an air-cooling system for a headlamp mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Fig. 1A is a front view of a motorcycle headlamp according to an embodiment, Fig. 1B is a cross-sectional view taken along line AA along the front-rear direction of the motorcycle headlamp shown in Fig. 1A, and Fig. 2 is an exploded perspective view of the motorcycle headlamp shown in Fig. 1A. When the motorcycle headlamp is viewed from the front, a light source unit 105 is disposed approximately in the center, and a transparent outer lens 101 is disposed in front of the light source unit 105. The outer lens 101 is formed with through-holes 108 at symmetrical positions above, below, left, and right of the light source unit 105, through which outside air can move in the front-rear direction.

[0014] FIG. 1B is an AA cross-sectional view of the headlamp of FIG. 1A cut along the front-rear direction, and FIG. 2 is an exploded perspective view of the headlamp. The outer lens 101 and the housing 102 are connected to form a lamp chamber 103 that houses a light source unit 105. The lamp chamber 103 forms a closed space surrounded by the outer lens 101 and the housing 102, and houses the light source unit 105 including a light source consisting of a semiconductor light-emitting element 106 such as an LED in the approximate center. The outer lens 101 is formed of a transparent resin such as acrylic or polycarbonate, and is attached in a state of covering the opening of the housing 102. The light source unit 105 has the semiconductor light-emitting element 106 provided on a mounting board, and a heat sink that transfers heat generated by the semiconductor light-emitting element 106 and dissipates heat is provided behind the mounting board in close contact with the mounting board. An inner lens is provided at a position facing the light-emitting surface of the semiconductor light-emitting element 106.

[0015] The through-hole portion 108 forms a hole portion through which outside air can pass by penetrating the top, bottom, left and right of the light source unit 105 in Fig. 1A, and penetrating the outer lens 101 and the housing 102 in Fig. 1B. As shown in Fig. 2, the through-hole portion 108 is formed by being surrounded by a wall formed by the extension of the outer lens 101 and the housing 102. Therefore, the through-hole portion 108 is shielded from the lamp chamber 103, and no air flows in or out of the lamp chamber 103. Depending on the weather, such as rain, moisture may get into the outside air, but even if moisture passes through the through-hole portion 108, the moisture does not enter the lamp chamber 103.

[0016] The through-holes 108 function as an air-cooling path that exhausts heat from the semiconductor light-emitting element 106, which is the light source of the light source unit 105, to the outside air by the outside air passing through the through-holes. The heat exhaust function can be adjusted by adjusting the number and area of ​​the through-holes arranged around the light source unit.

[0017] The flow of heat discharged from the light source of the light source unit 105 through the through-hole portion 108 will be described below. When the headlight is turned on, the air inside the lamp chamber 103 is heated by the semiconductor light-emitting element 106 and the heat sink in the light source unit 105, and the heated air rises. The heated and rising air eventually reaches the wall of the outer lens 101 and the housing 102 that form the lower side of the through-hole portion 108 located above the light source unit 105. The wall that forms the through-hole portion 108 is cooled by heat being removed by outside air passing through the through-hole portion 108. The air in the lamp chamber 103 that reaches the wall that forms the through-hole portion 108 has heat removed from the wall. The removed heat is discharged by the outside air from the surface of the wall that forms the through-hole portion 108. The cooled air descends toward the light source unit 105. When the descending air reaches the vicinity of the light source unit 105, it is warmed again by heat from the semiconductor light-emitting element 106 and the heat sink. The warmed air rises again and reaches the wall that defines the through-hole portion 108, and the heat is absorbed by the outside air through the wall.

[0018] By repeating this process, air convection occurs within the lamp chamber 103, and the heat exhaust effect within the lamp chamber 103 can be improved. The air-cooling path formed by the through-hole portion 108 is provided penetrating the lamp chamber 103 from front to back. Therefore, the air convecting within the lamp chamber 103 is cooled over a long distance. Furthermore, since outside air passes through the through-hole portion 108 in the front to back direction, the wall forming the through-hole portion 108 is constantly cooled by the outside air passing through, removing heat from it. As a result, the presence of the air-cooling path formed by the through-hole portion 108 causes the warmed air to be cooled rapidly, increasing the air convection speed.

[0019] In addition, by forming the through-hole portion 108, the gap between the light source unit 105 and the wall forming the through-hole portion 108 is narrowed. The narrowed gap also increases the convection speed of the air. In FIG. 1B, the through-hole portion 108 is provided not only above the light source unit 105 but also below it. In this case, the air in the lamp chamber 103 is cooled by the wall forming the lower side of the through-hole portion 108, but the narrowed gap between the light source unit 105 and the wall forming the through-hole portion 108 causes air convection to occur, thereby enhancing the heat exhaust effect in the lamp chamber 103. In FIG. 1A, the through-hole portion 108 is also formed on the left and right sides of the light source unit 105. The air warmed by the semiconductor light emitting element 106 and the heat sink is cooled by passing through the gap between the light source unit 105 and the wall forming the through-hole portion 108, and similarly enhances the heat exhaust effect in the lamp chamber 103.

[0020] The thickness of the wall around the through hole 108 may be formed thinner than the thickness of the portion where the outer lens 101 and the housing 102 form the outer periphery of the headlamp. A certain degree of thickness is required for the outer periphery to maintain the strength of the headlamp, but the wall around the through hole 108 does not need to be as thick. Therefore, by making the thickness of the wall around the through hole 108 thinner than the thickness of the outer periphery, it becomes easier to transfer heat inside the lamp chamber 103 to the outside air passing through the through hole 108, and the heat exhaust effect can be further improved.

[0021] The air cooling path provided by the through-holes 108 allows the warm air to be cooled rapidly, increasing the air convection speed and improving the heat dissipation performance of the heat sink. The improved heat dissipation performance of the heat sink allows the heat sink to be made smaller, which in turn allows for lower costs.

[0022] 3A to 3E show modified examples. In Fig. 3A, only one through-hole 108 is disposed above the light source unit 105. Since high temperatures have the tendency to move upward, if only one heat exhaust mechanism is provided, it would be preferable to dispose it above the heat source. However, after considering various factors, only one through-hole 108 may be disposed below the light source unit 105 as shown by the dashed line.

[0023] In Fig. 3B, two light source units 105A and 105B are arranged above and below the through hole 108. In Fig. 3C, through holes 108A and 108B are arranged above and below the light source unit 105, and through holes 108C and 108D are arranged on the left and right of the light source unit 105. Furthermore, 108E, 108F, 108G, and 108H are arranged between the through holes 108A and 108C, between 108A and 108D, between 108B and 108C, and between 108B and 108D, respectively. By arranging a large number of through holes 108 around the light source unit 105, the heat exhaust effect can be further improved.

[0024] In Fig. 3D, through-holes 108A, 108B, 108C, and 108D are arranged above, below, to the left and right of light source unit 105, and position lamps 112 are arranged outside of them. In Fig. 3E, light source unit 105 is arranged below through-hole 108, and camera unit 114 is arranged above through-hole 108. By arranging through-hole 108 in a position close to and facing above light source unit 105, the heat dissipation effect from light source unit 105 is improved, and it becomes possible to arrange other devices in the empty space.

[0025] FIG. 4 shows a configuration in which fins 109 are provided within the through-hole. In the figure, one through-hole 108x is divided into five parts by four fins 109. The fins 109 serve as walls that separate the divided through-holes. The surface area of ​​the through-hole is increased, improving heat dissipation. Although vertical fins are shown, the direction of the fins is not limited. The fins may extend from the outer lens or from the housing.

[0026] In addition, regarding the outer lens 101 and the housing 102 that form the wall around the through hole portion 108, the outer lens 101 needs to be a light-transmitting material, but the housing 102 does not necessarily need to be a light-transmitting material, and is usually formed of a non-transmitting material. Here, the housing, which is a non-transmitting material, is more likely to contain a thermally conductive filler. Therefore, by using a material containing a thermally conductive filler, such as carbon or ceramic, as the housing material, the heat dissipation by the housing 102 can be improved. This makes it easier to transfer the heat in the lamp chamber 103 to the outside air passing through the through hole portion 108, and the heat exhaust effect can be further improved. In this case, the heat exhaust effect can be further improved by increasing the proportion of the wall formed by the housing 102. However, if the housing 102 is located forward of the emission surface of the light source unit 105, it will partially block the light emitted from the light source, which may affect the light distribution characteristics. Therefore, by positioning the housing 102 forward to an extent that does not affect the light distribution characteristics and increasing the proportion of the wall formed by the housing 102, the heat dissipation effect can be further improved.

[0027] Furthermore, by increasing the thermal conductivity of the housing 102, a difference in thermal conductivity occurs compared to the outer lens 101. Therefore, the air passing through the wall portion formed by the housing 102 is cooled more than the air passing through the wall portion formed by the outer lens 101, and air convection occurs, making it possible to further increase the convection speed.

[0028] It will be obvious to those skilled in the art that various other modifications, improvements, combinations, etc. are possible. [Explanation of symbols]

[0029] 101 outer lens, 102 housing, 103 lamp chamber, 105 light source unit, 108 through hole portion, 109 fin

Claims

1. A motorcycle headlamp, comprising: a light source unit disposed in a lamp chamber sealed by an outer lens and a housing; and light emitted from the light source unit is used for illumination; A motorcycle headlamp having at least one through hole formed through an outer lens and a housing in the fore-and-aft direction of the vehicle, wherein outside air can move from the front to the rear within the through hole as the vehicle moves.

2. The motorcycle headlamp according to claim 1 , wherein the light source unit includes a light source including a semiconductor light emitting element and an optical system having a function of concentrating the emitted light.

3. The motorcycle headlamp according to claim 1 or 2, wherein the through hole includes a portion that is disposed at a position higher than the light source unit.

4. The motorcycle headlamp according to claim 1 or 2, wherein the through hole is surrounded by the outer lens or the housing.

5. The motorcycle headlamp according to claim 1 or 2, wherein the through holes are arranged at symmetrical positions above and below and to the left and right of the light source unit.

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