Vehicle light fixture

Abstract

To provide a vehicle light fixture which can secure shock resistance even when a lens main body is made of acrylic resin.SOLUTION: The present invention is directed to a vehicle light fixture having a lamp body, and an outer lens forming a light chamber together with the lamp body. The outer lens has a lens main body, and a fastening part provided at an outer peripheral part of the lens main body and fastened to the lamp body. The lens main body is formed of acrylic resin. The fastening part is made of a material that includes a thermoplastic polyurethane elastomer and has a coefficient of elasticity of 2000 MPa to 3200 MPa.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle lamp. [Background technology]

[0002] In response to the global movement toward carbon neutrality, recycling has been drawing increasing attention. In vehicle lighting, a structure is known in which a foam gasket material is used to bond the lamp body and outer lens together (see, for example, Patent Document 1). Since the foam gasket material can be peeled off more easily than hot melt adhesives, it is being considered to peel off the foam gasket material to disassemble the lamp body and outer lens, and recover and recycle the respective resin materials.

[0003] Polycarbonate, which is often used for outer lenses, has excellent impact resistance and transparency. In order to improve scratch resistance and weather resistance, the surface of polycarbonate is sometimes subjected to a hard coat treatment (for example, see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-064329 [Patent Document 2] JP 2023-035413 A Summary of the Invention [Problem to be solved by the invention]

[0005] It is difficult to peel off the hard coat from polycarbonate that has been subjected to a hard coat treatment. When polycarbonate is mixed with other resins such as hard coats, there is a problem that recycled resin of sufficient quality cannot be obtained by chemical recycling.

[0006] On the other hand, acrylic resin is easily chemically recycled because it is decomposed into methyl methacrylate monomer by thermal decomposition. For this reason, the use of acrylic resin for the outer lens has been considered. However, acrylic resin has lower impact resistance than polycarbonate. Also, acrylic resin is more easily broken than polycarbonate, so if the outer lens is molded from acrylic resin, there is a risk that the fastening portion of the outer lens to the lamp body may break when the fastening portion is fastened to the lamp body with a fastening member such as a screw.

[0007] An object of the present invention is to provide a vehicle lamp that can ensure impact resistance even when an acrylic resin is used. [Means for solving the problem]

[0008] In order to solve the above problems, the vehicle lamp of the present invention comprises a lamp body and an outer lens which forms a lamp chamber together with the lamp body, the outer lens having a lens body and a fastening portion which is provided on the outer edge of the lens body and is fastened to the lamp body, the lens body being made of acrylic resin, and the fastening portion being made of a material which contains a thermoplastic polyurethane elastomer and has a flexural modulus of elasticity of 2000 MPa to 3200 MPa. Effect of the Invention

[0009] According to the present invention, at least the main body of the outer lens is made of acrylic resin, which contributes to chemical recycling. Furthermore, even if acrylic resin is used, the fastening portion can absorb the impact received by the outer lens, thereby improving impact resistance. Furthermore, since the fastening portion has a suitable impact resistance, the outer lens can be fastened to the lamp body with a fastening member such as a screw. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a side cross-sectional view of a vehicle headlamp. [Diagram 2] FIG. 2 is a front view of the housing 30 as seen from the front. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0012] A vehicle headlamp will be described as a vehicle lamp according to the present invention. Fig. 1 is a side cross-sectional view of the vehicle headlamp. As shown in Fig. 1, the vehicle headlamp has an outer lens 1, a lamp unit 10, an aiming mechanism 20, and a housing 30 (lamp body). In Fig. 1, an arrow F indicates the forward direction, and an arrow B indicates the rearward direction. In Figs. 1 and 2, an arrow U indicates the vertically upward direction, and an arrow D indicates the vertically downward direction.

[0013] The outer lens 1 and the housing 30 form a lamp chamber. The lamp unit 10 is disposed inside the lamp chamber. The outer lens 1 is made of a transparent resin. The outer lens 1 transmits light emitted from the lamp unit 10.

[0014] The outer lens 1 has a lens body 2 and a fastening portion 3. The fastening portion 3 is provided on the outer edge of the lens body 2, and is fastened to a housing 30 by a fastener 6. 1, the fastening part 3 has an insertion part 4 and a flange 5. The insertion part 4 is the rear edge of the fastening part 3, and is inserted into a mounting groove 32 (described later) of the housing 30. The insertion part 4 is adhered to the mounting groove 32 with a hot melt adhesive 40 (described later), whereby the outer lens 1 and the housing 30 are integrally formed.

[0015] A flange 5 is provided on the outer peripheral edge of the fastening portion 3. The flange 5 is provided so as to protrude further outward than an outer lens mounting portion 31, which will be described later. By providing the flange 5, when attaching the outer lens 1 to the housing 30, the flange 5 can be abutted against the outer lens mounting portion 31 of the housing 30, and the insertion portion 4 can be positioned at a predetermined location within the mounting groove 32. Furthermore, the flange portion 5 is fastened to the outer lens mounting portion 31 by a fastener 6. Furthermore, the flange portion 5 and the outer lens mounting portion 31 may be fastened to each other by a screw or the like (not shown).

[0016] The lamp unit 10 includes a light source 11, a reflector 12, an inner lens 13, a cable 14, and a light source stand 15. Light emitted from the light source 11 is reflected by the reflector 12 and enters the inner lens 13. Light transmitted through the inner lens 13 passes through the outer lens 1 and is emitted forward of the vehicle headlamp. The light source 11 and the reflector 12 are attached to the light source stand 15. The inner lens 13 is attached to the light source stand 15 via a lens holder (not shown). The lamp unit 10 may include a shade (not shown) that blocks a portion of the light emitted from the light source 11 to form a specific light distribution pattern. The extension 16 is provided around the inner lens 13 inside the lamp chamber. The extension 16 is a member that hides the inner surface of the housing 30 inside the lamp chamber and the aiming mechanism 20 from the outside of the outer lens 1, and enhances the appearance design of the lamp. The design surface of the extension 16 may be subjected to a mirror finish or a texture finish.

[0017] The aiming mechanism 20 has a rectangular, plate-like holder 21, an adjuster screw 22, and an aiming actuator 23. Two upper corners of the rectangular holder 21 are attached to the housing 30 via support shafts (not shown) and the adjuster screws 22. One lower corner of the rectangular holder 21 is attached to the housing 30 via the aiming actuator 23.

[0018] The adjuster screw 22 is screwed into the upper part of the holder 21. The head of the adjuster screw 22 passes through the adjuster screw attachment portion 36 of the housing 30 and is exposed to the outside. The adjuster screw 22 can be rotated by rotating the head of the adjuster screw 22. When the adjuster screw 22 rotates, the upper part of the holder 21 can be moved in the front-rear direction. After the lamp unit 10 is mounted, the direction of the optical axis of the lamp unit 10 can be adjusted by operating the adjuster screw 22 before shipping or during vehicle inspection.

[0019] The aiming actuator 23 has a motor 24 and an aiming screw 25. The aiming screw 25 is screwed into the lower part of the holder 21. The motor 24 is attached to a motor attachment portion 37 of the housing 30. When the motor 24 is operated, the aiming screw 25 rotates, moving the lower part of the holder 21 in the front-rear direction. When the vehicle is traveling, if the center of gravity of the vehicle moves in the longitudinal direction and it becomes necessary to adjust the optical axis of the lamp unit 10, the aiming actuator 23 is operated to adjust the optical axis of the lamp unit 10.

[0020] Fig. 2 is a front view of the housing 30. As shown in Fig. 2, the housing 30 has an outer lens attachment portion 31, a cable insertion portion 33, a vehicle body attachment portion 35, an adjuster screw attachment portion 36, a motor attachment portion 37, and a support shaft attachment portion 38.

[0021] The outer lens mounting part 31 is provided on the front edge of the housing 30. The outer lens mounting part 31 is provided with a mounting groove 32 that opens forward. A hot melt adhesive 40 is applied in a molten state to the mounting groove 32. The outer lens 1 is fixed to the housing 30 by inserting the insertion part 4 of the fastening part 3 into the molten hot melt adhesive 40 in the mounting groove 32 and cooling it. In this state, the outer lens 1 may be fixed to the housing 30 by fastening the flange part 5 to the mounting groove 32 with a fastener 6, a screw (not shown), or the like.

[0022] It should be noted that the foamed gasket material described in Patent Document 1 may be used instead of the hot melt adhesive 40. As described in Patent Document 1, the foamed gasket material can be peeled off more easily than the hot melt adhesive.

[0023] The cable insertion portion 33 has an insertion hole 34 through which the cable 14 is inserted. The insertion hole 34 allows electric wires extending from electronic devices such as the lamp unit 10 and the aiming actuator 23 arranged in the lamp chamber to pass through to the outside. The vehicle body mounting portion 35 is a portion for mounting the housing 30 to the vehicle body. The adjuster screw attachment portion 36 is a portion where the adjuster screw 22 is attached to the housing 30 . The motor attachment portion 37 is a portion where the motor 24 is attached to the housing 30 . The support shaft attachment portion 38 is a portion where the support shaft is attached.

[0024] In this embodiment, the lens body 2 of the outer lens 1 is made of acrylic resin. On the other hand, the fastening portion 3 is made of a material containing a thermoplastic polyurethane elastomer and having a flexural modulus of 2000 MPa to 3200 MPa. Here, the flexural modulus is the flexural modulus defined in JIS K7171.

[0025] Thermoplastic polyurethane elastomers (hereinafter referred to as "TPU") are urethane-based thermoplastic elastomers (TPEs). TPUs are block copolymers consisting of hard segments and soft segments, both of which have urethane bonds. The hard segments are formed by urethane bonds between diisocyanates and short-chain diols. The soft segments are formed by urethane bonds between long-chain polyols such as polyester polyols, polyether polyols, and polycarbonate polyols and diisocyanates.

[0026] TPUs are further classified as follows (JIS K6418:2007, ISO18064:2003) according to the type of hydrocarbon residue between the urethane bonds of the hard segments (aromatic or aliphatic) and the bonding style of the soft segments (ester, ether and / or carbonate).

[0027] TPU-ARES: hard segments are aromatic, soft segments are polyester. TPU-ARET: The hard segment is aromatic and the soft segment is polyether. TPU-AREE: The hard segment has aromatic rings and the soft segment has ester and ether bonds. TPU-ARCE: The hard segment is aromatic and the soft segment is polycarbonate. TPU-ARCL: hard segment is aromatic, soft segment is polycaprolactone. TPU-ALES: The hard segment is aliphatic and the soft segment is polyester. TPU-ALET: The hard segment is aliphatic and the soft segment is polyether.

[0028] The flexural modulus can be adjusted by selecting the hard and soft segments of the TPU and adjusting the ratio of the hard and soft segments. Alternatively, a material having a flexural modulus of 2000 MPa to 3200 MPa may be obtained by mixing other resins with the above TPU. For example, the material constituting the fastening portion may be a mixture of the above-mentioned TPU and acrylic.

[0029] For example, the material constituting the fastening portion may contain 70 to 80 mass% acrylic resin and 20 to 30 mass% TPU. By containing 20 to 30 mass% TPU, the flexural modulus of the material constituting the fastening portion can be set to 2000 MPa to 3200 MPa.

[0030] Alternatively, acrylic and TPU may be copolymerized to form the material for the fastening part. In this case, the fastening part can be formed using a block copolymer containing 70 to 80 mass % of acrylic blocks and 20 to 30 mass % of TPU blocks.

[0031] According to the present invention, at least the lens body 2 of the outer lens 1 is made of acrylic resin, which contributes to chemical recycling. Additionally, the fastening portion 3 of the outer lens 1 is made of a material containing a thermoplastic polyurethane elastomer and having a flexural modulus of 2000 MPa to 3200 MPa. Therefore, the fastening portion 3 can absorb any impact received by the outer lens 1. Since the lens body 2 is less susceptible to impact, it is less likely that the lens body 2 will break and shatter when, for example, another object collides with the vehicle lamp, thereby improving impact resistance. Furthermore, since the fastening portion 3 has a suitable shock resistance, the outer lens 2 can be attached to the lamp body 1 via the fastening portion 3 using a fastening member such as a screw.

[0032] The outer lens 1, in which the lens body 2 and the fastening portion 3 are integrally molded, can be manufactured by two-color molding. For example, the lens body 2 may be molded first, and then the fastening portion 3 may be molded. Specifically, first, acrylic resin is heated to approximately 250°C and injected into a lens body mold for molding the lens body 2 to form the lens body 2. Next, the lens body 2 is placed in an outer lens mold for molding the outer lens 1. Next, a material constituting the fastening portion is heated to 200 to 220°C and injected into the outer lens mold. As a result, the lens body 2 and the fastening portion 3 are molded integrally.

[0033] In this case, because the melting temperature of the TPU contained in the fastening portion 3 is lower than the melting temperature of the acrylic resin that constitutes the lens body 2, the surface of the lens body 2 does not melt when the fastening portion 3 is molded. Therefore, the degree of adhesion between the lens body 2 and the fastening portion 3 is low, and the lens body 2 and the fastening portion 3 can be easily separated when the outer lens 1 is recycled.

[0034] Alternatively, the fastening portion 3 may be formed first, and then the lens body 2 may be molded. Specifically, first, the material constituting the fastening portion is heated to 200-220°C and injected into a fastening portion mold for molding the fastening portion. Next, the fastening portion 3 is placed in an outer lens mold for molding the outer lens 1. Next, acrylic resin is heated to approximately 250°C and injected into the outer lens mold. As a result, the lens body 2 and the fastening portion 3 are molded integrally.

[0035] In this case, since the melting temperature of the acrylic resin constituting the lens body 2 is higher than the melting temperature of the TPU contained in the fastening portion 3, the surface of the fastening portion 3 melts during molding of the lens body 2, fusing the lens body 2 and the fastening portion 3. This makes it possible to strengthen the adhesion between the lens body 2 and the fastening portion 3.

[0036] In an environment in which the vehicle headlamp is used, the lens body 2 and the fastening portion 3 are maintained in close contact with each other. When disassembling the vehicle headlamp, first, the hot melt adhesive 40 or the foam gasket material is softened by heating, and the outer lens 1 is removed from the housing 30. After that, the fastening portion 3 is peeled off from the lens body 2, and the lens body 2 and the fastening portion 3 can be recycled separately. EXAMPLES

[0037] The following materials (1) to (5) were prepared as materials for forming the fastening portion. In addition, the feasibility of injection molding, bending modulus, and Charpy impact test were performed using the methods described below.

[0038] (1) TPU The TPU used was a highly weather-resistant, non-yellowing TPU.

[0039] (2) A mixture of TPU and acrylic (20% TPU) Polymethyl methacrylate resin (PMMA) was mixed at 80 mass % and TPU (1) was mixed at 20 mass % to obtain a mixture of TPU and acrylic.

[0040] (3) A mixture of TPU and acrylic (30% TPU) Polymethyl methacrylate resin (PMMA) was mixed at 70 mass % and TPU (1) was mixed at 30 mass % to obtain a mixture of TPU and acrylic.

[0041] (4) General-purpose acrylic resin Polymethyl methacrylate resin (PMMA) was used.

[0042] [Flexural modulus] A dumbbell-shaped test piece conforming to JIS K7139 was injection molded. This test piece was placed between supporting points with a distance L of 64 mm, and the load P and deflection w were measured when the center of the test piece was pressed with an indenter at a test speed of 5 mm / min in an environment of 25°C, and the stress σ and strain ε were calculated. where σ=3PL / 2bh 2 and ε=6hw / L 2 It is. When the deflection w1 is such that the strain ε1 = 0.05%, the load P1 applied to the measuring device gives the stress σ1 = 3P1L / 2bh 2 Calculate the stress σ2 = 3P2L / 2bh from the load P2 applied to the measuring device at the deflection w2 where the strain ε2 = 0.25%. 2 was calculated. The flexural modulus E was calculated from the obtained value as follows. E = (σ2-σ1) / (ε2-ε1)

[0043] The test piece made from material (1) was too soft to measure the flexural modulus (evaluation: N / A). The flexural modulus of the test pieces made of material (2) was 2500-3200 MPa. (3) The flexural modulus of the test pieces made of the material was 2000-2300 MPa. The flexural modulus of the test piece made of material (4) was 3400 MPa. The results are shown in Table 1.

[0044] [Charpy impact test] An unnotched test piece having a width b=10 mm, a thickness h=4 mm, and a length l=80 mm was cut out from the material constituting the above-mentioned fastening portion formed into a plate shape. The unnotched Charpy impact strength was measured in accordance with JIS K7111-1:2021. Both ends of the test specimen were supported horizontally on a pair of test specimen supports. A constant high-speed bending impact was applied to the test specimen by a single downward swing of a pendulum passing through the center between the test specimen supports. The impact energy absorbed at the time of the test specimen's destruction was calculated by dividing it by the initial cross-sectional area of ​​the test specimen.

[0045] The test piece made from material (1) did not break (NB: No Break). (2) The unnotched Charpy impact strength of the test piece made of the material is 30-74 J / cm 2 It was. The test piece made of material (3) did not break (NB: No Break). (4) The unnotched Charpy impact strength of the test piece made of the material is 21 J / cm 2 It was. The results are shown in Table 1.

[0046] [Possibility of injection molding] The lens body was molded using the general-purpose acrylic resin (4) above, and the fastening portion was molded in two colors using the materials (1) to (5) above. When material (1) was used in the fastening part, the shape of the fastening part could not be maintained (rating: Fail). When materials (2) to (4) were used for the fastening parts, the fastening parts could be molded (evaluation: acceptable). The evaluation results are shown in Table 1.

[0047] [Table 1]

[0048] In this manner, by using a material containing a thermoplastic polyurethane elastomer and having a flexural modulus of elasticity of 2000 MPa to 3200 MPa for the fastening portion, the lens body and the fastening portion can be molded integrally.

[0049] When the outer lens 1 having such a structure is used, if something collides with the lens body 2, the fastening portion 3 absorbs the impact, making the lens body 2 less likely to break.

[0050] In the above embodiment, a vehicle headlamp has been described as a vehicle lamp, but the present invention is not limited to this. The present invention can be applied to a rear combination lamp, a turn signal lamp, a fog lamp, etc. as a vehicle lamp. [Explanation of symbols]

[0051] 1 Outer lens 2 Lens body 3 Fastening Part 4 Insertion section 5 Flange 6 Fasteners 10 Lamp unit 11 Light source 12 Reflector 13 Inner Lens 14 Cable 15 Light source stand 16 Extension 20 Aiming mechanism 21 Holder 22 Adjuster screw 23 Aiming Actuator 24 Motor 25 Aiming Screw 30 Housing (lamp body) 31 Outer lens attachment part 32 Mounting groove 33 Cable insertion part 35 Vehicle mounting part 36 Adjuster screw mounting part 37 Motor mounting part 38 Support shaft attachment part 40 Hot melt adhesives

Claims

1. The lamp body and an outer lens forming a lamp chamber together with the lamp body; The outer lens is The lens body, a fastening portion provided on an outer edge of the lens body and fastened to the lamp body; having The lens body is made of acrylic resin, The fastening portion is made of a material containing a thermoplastic polyurethane elastomer and having a flexural modulus of 2000 MPa to 3200 MPa. Vehicle lighting fixtures.

2. The vehicular lamp according to claim 1 , wherein the lens body and the fastening portion are fused together.

3. 2. The vehicular lamp according to claim 1, wherein the fastening portion and the lamp body are joined together by a hot melt adhesive.

4. 2. The vehicular lamp according to claim 1, wherein the fastening portion is made of a mixture of a thermoplastic polyurethane elastomer and an acrylic resin.

5. 5. The vehicular lamp according to claim 4, wherein the fastening portion contains 20 to 30 mass % of a thermoplastic polyurethane elastomer.

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