Vehicle lighting

Abstract

The present invention provides a vehicle light fixture having an extension made of polypropylene resin. [Solution] The vehicle lighting fixture 10 has a light source unit 40 and an extension body 50 surrounding the light source unit 40 arranged in a light chamber space 11 formed by a lamp cover 20 and a lamp body 30. The extension body 50 is molded from a light-opaque polypropylene resin material and has a heat dissipation part 51 on its back surface.

Description

Technical Field

[0001] The present disclosure relates to an extension provided inside a vehicle lamp.

Background Art

[0002] In recent years, from the perspective of carbon neutrality, aiming to improve fuel efficiency by reducing the weight of automobiles, even in vehicle lamps as vehicle parts, weight reduction using resin materials with low CO2 emissions is required. In particular, the extension arranged as a decorative member inside the vehicle lamp is required to achieve both weight reduction and high design quality as a design part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, vehicle lamp extensions are known to be made of polycarbonate resin or polybutylene terephthalate resin with metal vapor deposition on the surface, as shown in Patent Document 1, from the viewpoints of dimensional stability and reflectivity during molding.

[0005] By arranging such an extension inside a vehicle lamp, the structures inside the lamp can be effectively concealed, and at the same time, due to the pattern of the metal vapor deposition, it is visually recognized as a highly designed extension from the outside of the lamp. However, since the specific gravity of the resin is heavy, the weight of the lamp parts increases.

[0006] Therefore, if lightweight polypropylene resin is used as an extension material, there is a risk of deformation due to heat from sunlight or when the light fixture is turned on, because its heat distortion temperature is lower compared to polycarbonate resin or polybutylene terephthalate resin.

[0007] This disclosure is made in consideration of the circumstances described above, and aims to provide an extension that does not undergo thermal deformation even when made of polypropylene resin, in order to further reduce the weight of vehicle lighting fixtures. [Means for solving the problem]

[0008] The vehicle lighting fixture of this disclosure comprises a light source unit and an extension surrounding the light source unit, arranged in a lamp chamber formed by a lamp cover and a lamp body, wherein the extension is molded from an opaque polypropylene resin material and has a heat dissipation portion on its back surface.

[0009] Furthermore, the heat dissipation portion is defined as an uneven portion that protrudes from the back surface of the extension.

[0010] Furthermore, the aforementioned uneven portion is a honeycomb-shaped or grid-shaped rib that protrudes planarly from the back surface of the extension.

[0011] Furthermore, the heat dissipation portion is defined as a heat-dissipating coating formed on the back surface of the extension.

[0012] According to this disclosure, by using opaque polypropylene resin material for the extension, it is lightweight and reduces CO2 emissions during molding, contributing to carbon neutrality.

[0013] Furthermore, when the resin used in the extension is recycled, the inside of the light fixture can be concealed without applying a metal film such as aluminum vapor deposition to the surface, as in conventional methods, thus eliminating the need to separate the extension body from the metal film.

[0014] Furthermore, the extension according to this disclosure has a heat dissipation section on its back surface, which enhances heat dissipation for polypropylene resin, which is prone to thermal deformation, and suppresses heat generated inside the light fixture and thermal deformation of the extension member due to sunlight irradiation.

[0015] Furthermore, the extension according to this disclosure has a protruding recessed portion that extends from the back surface of the extension as a heat dissipation portion, thereby increasing the surface area of ​​the extension member to improve heat dissipation, as well as increasing the strength of the extension member and suppressing thermal deformation.

[0016] Furthermore, the extension according to this disclosure increases the surface area of ​​the extension and enhances heat dissipation by forming the heat dissipation portion, which is the uneven portion, with honeycomb-shaped or lattice-shaped ribs that protrude planarly from the back surface of the extension, while also increasing the strength of the extension member and suppressing thermal deformation.

[0017] Furthermore, the extension according to this disclosure has a heat dissipation section configured as a heat-dissipating coating formed on the back surface of the extension member. This makes it possible to form a flat heat dissipation surface on the back surface of the extension without changing the basic thickness of the extension body, thereby reducing the cost of molds required to integrally mold the heat dissipation section. [Effects of the Invention]

[0018] In summary, this disclosure provides an extension that is lightweight, highly rigid, and easily recyclable. [Brief explanation of the drawing]

[0019] [Figure 1] This is a front view of a vehicle light fixture illustrating an embodiment of the present disclosure. [Figure 2] This is a cross-sectional view along line AA in Figure 1. [Figure 3] This is a cross-sectional view showing a first embodiment of the extension of the present disclosure. [Figure 4] It is a cross-sectional view showing a second embodiment of the extension of the present disclosure. [Figure 5] It is a cross-sectional view showing a third embodiment of the extension of the present disclosure.

Embodiments for Carrying out the Invention

[0020] Hereinafter, an explanation will be given based on the drawings of embodiments in which the extension in the vehicle lamp of the present disclosure is embodied.

Examples

[0021] Fig. 1 is a front view showing an example of the configuration of a vehicle lamp according to an embodiment of the present disclosure, and Fig. 2 shows a cross-sectional view taken along the line A-A in Fig. 1.

[0022] As shown in Figs. 1 and 2, a vehicle lamp 10 showing an embodiment of the present disclosure includes a Hi-beam unit and a Lo-beam unit each composed of an LED light source substrate, a reflector, a heat sink, etc. in a lamp chamber space 11 formed by a lamp cover 20 attached to a lamp body 30, and an extension body 50 disposed in the lamp chamber space 11 surrounding the outer peripheral region of the inner lens 41 of each light source unit 40.

[0023] This extension body 50 is formed by appropriately selecting and blending carbon black, titanium oxide, iron oxide, graphite, etc. as pigments based on polypropylene, and adding an organic crystal nucleating agent such as an aromatic carboxylic acid metal salt or a phosphoric acid metal salt, thereby adjusting the surface roughness to 20 nm or less and injection molding a dark-colored resin material with a low light transmittance, for example, black.

[0024] In addition, on the back surface of the extension body 50, which is the non-design surface side, a plurality of rib-shaped heat dissipation parts 51 protruding rearward are integrally formed, and a fixing part (not shown) for fixing the extension body 50 to the lamp body 30 is provided at the outer end thereof.

[0025] An opening is provided in a part of the black extension body 50, and by arranging it inside the vehicle lamp 10 so as to surround each light source unit 40 through this opening, other lamp components (not shown) arranged inside the lamp chamber space 11 are prevented from being visible from outside the lamp.

[0026] Furthermore, the polypropylene extension body 50 has a lower specific gravity and lower water absorption rate compared to polycarbonate, which contributes to reducing the weight of the light fixture. In addition, less moisture is released from the extension body 50, preventing fogging inside the light fixture.

[0027] Next, an embodiment of the heat dissipation section formed on the back surface of the extension will be described using Figures 3 to 5.

[0028] As shown in Figures 3(A) and (B), the extension body 50 has a plurality of pin-shaped heat dissipation parts 51 that protrude rearward from the main body portion which has a basic wall thickness t. The height H, which indicates the amount of protrusion of each of these pin-shaped heat dissipation parts, is set to 10 mm or less, taking into account the effect of sink marks during molding, for a basic wall thickness t in the range of 1.0 to 2.5 mm. In addition, the width d of the upper part of the pin is set in the range of 0.1 to 1.25 mm, and the width D of the lower part has a width of d or more and is set in the range of 0.1 to 1.25 mm.

[0029] In this way, by adjusting the basic wall thickness of the extension body 50 and the height of the pins, the surface area of ​​the back of the extension is increased in an uneven manner, and by dissipating heat received from sunlight or the light source unit from the rear of the light fixture, the risk of thermal deformation of the polypropylene material can be reduced.

[0030] Furthermore, while the pins molded integrally with the extension body 50 carry the risk of sink marks occurring on the surface side of the extension body 50, limiting the height of the pins and using a dark-colored material such as black for the extension body 50 makes the sink marks on the surface side of the extension less noticeable, and also increases the surface area, thereby providing a heat dissipation effect.

[0031] Next, a modified example of the rib-shaped heat dissipation section will be explained using Figures 4(A) and (B).

[0032] The rib-shaped heat dissipation section 51 may have a shape in which multiple ribs are connected in a honeycomb or grid pattern, as shown in Figures 4(A) and (B). By using this connected shape, each rib is firmly fixed to the other relative to a single, protruding pin-shaped rib, which further enhances the deformation prevention effect of the extension body 50 and reduces the risk of damaging the ribs when assembling the extension body 50 to the vehicle lighting fixture.

[0033] When integrally molding such rib-shaped heat dissipation sections 51 with the extension body 50, there is a risk of sink marks occurring on the surface (design surface) of the extension. However, as mentioned above, since the extension 50 is made of a black material, the sink marks on the surface are not very noticeable.

[0034] Next, other modified examples of the heat dissipation section, besides the rib-shaped design, will be explained using Figure 5.

[0035] As shown in Figure 5, a heat-dissipating sheet can be attached to the back surface of the extension 50 as a heat-dissipating coating 61, or a heat-dissipating paint can be applied.

[0036] When a heat-dissipating sheet is attached, for example, a thermally conductive acrylic resin with a thickness of 50 to 500 μm and a thermal conductivity of 5 W / mK or higher is integrated with the back surface of the extension body 50 by adhesive or insert molding.

[0037] When applying a heat-dissipating coating 61, for example, a silicone-based coating with a thickness of 0.5 to 20 μm and a thermal conductivity of 5 W / mK or higher is applied to the entire back surface of the extension body 50. With such a heat-dissipating coating 61, no unevenness is formed on the back surface of the extension body 50, eliminating the risk of sink marks during molding, and also eliminating the risk of rib damage due to contact with other parts when assembling the extension body 50 to a vehicle lighting fixture.

[0038] Based on the above, by adopting polypropylene, which has a lower specific gravity and lower water absorption rate than polycarbonate, as the resin material for the extension used in vehicle lighting fixtures, it is possible to reduce the weight of the extension component and suppress fogging problems inside the lighting fixture.

[0039] Furthermore, in order to eliminate the risk of thermal deformation due to the use of polypropylene, which has a low thermal deformation temperature, the extension of this disclosure has a heat dissipation section formed on its back surface. This increases the heat dissipation and strength of the extension, and effectively prevents thermal deformation of the extension due to heat generated inside the light fixture or sunlight irradiation. [Explanation of Symbols]

[0040] 10 Vehicle lighting fixtures 20 Lamp Cover 30 Lamp Body 40 light source units 41 Inner Lens 50 Extension Body 51 Heat radiation part 61 Heat-dissipating coating

Claims

1. In a vehicle lighting fixture in which a light source unit and an extension surrounding the outer periphery of the light source unit are arranged within a lighting chamber defined by a lamp cover and a lamp body, The aforementioned extension is made of opaque polypropylene resin and has a heat dissipation section on its back surface, and is a vehicle light fixture.

2. The vehicle lamp according to claim 1, wherein the heat dissipation portion is an uneven portion that protrudes from the back surface of the extension.

3. The vehicle light fixture according to claim 2, wherein the aforementioned uneven portion is a honeycomb-shaped or grid-shaped rib that protrudes planarly from the back surface of the extension.

4. The vehicle lamp according to claim 1, wherein the heat dissipation portion is a heat-dissipating coating formed on the back surface of the extension.

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