Optical axis adjustment screw and vehicle lamp including the same

Abstract

To provide an optical axis adjustment screw, that achieves weight reduction while maintaining a necessary mechanical strength, and a vehicular lamp including the same.SOLUTION: There is provided a resin optical axis adjustment screw 100 for adjusting a light emission direction of a vehicle lamp. The optical axis adjustment screw 100 includes a skin layer 110 formed on a surface of the optical axis adjustment screw 100, and a foam layer 120 formed inside the skin layer 110 and containing a plurality of cells 121. An average diameter of the cells 121 in the foam layer 120 is 10 to 100 μm.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an optical axis adjusting screw and a vehicle lamp including the same. [Background technology]

[0002] Vehicle lighting fixtures such as headlamps are provided with an optical axis adjustment screw as one component of an aiming mechanism for adjusting the optical axis direction, which serves as a reference for the light irradiation direction. For example, Patent Document 1 discloses an optical axis adjustment screw having a hollow portion extending over at least a part of the intermediate portion between a first end and a second end. Patent Document 1 also discloses that the optical axis adjustment screw is made of resin and formed by injection molding.

[0003] Generally, resin parts are manufactured by various methods depending on the shape and material. For example, Patent Document 2 discloses a method for manufacturing a resin product having foam inside by introducing a polymer material mixed with a supercritical fluid into a mold and then solidifying the polymer material in the mold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-130712 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-15398 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, vehicle lighting fixtures have become larger and heavier as they have become more functional, such as by incorporating ADB (Adaptive Driving Beam) technology. Against this backdrop, there is a demand for some of the components that make up vehicle lighting fixtures to be lighter while maintaining the necessary mechanical strength. The optical axis adjustment screw described in Patent Document 1 is lighter while maintaining the necessary mechanical strength by providing a hollow portion in a portion of the screw. However, in today's world where both mechanical strength and light weight are required, it is also important to consider other methods.

[0006] Patent Document 2 describes how to reduce the weight of a resin product by foaming the inside of the resin product, but does not describe applying this to an optical axis adjustment screw. Naturally, it does not disclose anything about how to achieve both the necessary mechanical strength and weight reduction in an optical axis adjustment screw.

[0007] An object of the present disclosure is to provide a screw for adjusting an optical axis that is lightweight while maintaining necessary mechanical strength, and a vehicle lamp including the screw. [Means for solving the problem]

[0008] An optical axis adjustment screw according to one aspect of the present disclosure includes: A resin optical axis adjustment screw for adjusting the light emission direction of a vehicle lamp, a skin layer formed on the surface of the optical axis adjusting screw; a foam layer formed inside the skin layer and containing a plurality of bubbles; The average diameter of the bubbles in the foamed layer is 10 to 100 μm.

[0009] A vehicle lamp according to one aspect of the present disclosure includes the optical axis adjustment screw. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a screw for adjusting an optical axis that is lightweight while maintaining the necessary mechanical strength, and a vehicle lamp including the screw. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing a vehicle lamp according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram illustrating an optical axis adjustment screw according to an embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram illustrating an internal structure of an optical axis adjustment screw according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described below based on embodiments with reference to the drawings. Identical or equivalent components, members, and processes shown in each drawing are designated by the same reference numerals, and redundant description will be omitted where appropriate. Furthermore, the dimensions of each member shown in the drawings may differ from the actual dimensions of each member for the sake of convenience. Furthermore, the "front," "rear," "up," and "down" directions shown in the drawings are relative directions set for the sake of convenience. In this specification, the "front-rear direction" includes the front and rear directions, and the "up-down direction" includes the up and down directions.

[0013] (vehicle lighting fixtures) First, a vehicle lamp according to an embodiment of the present disclosure will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view (longitudinal cross-sectional view) showing a vehicle lamp 1 according to this embodiment. The vehicle lamp 1 shown in FIG. 1 is, for example, a headlamp of a vehicle, and is disposed on the left and right sides of the front of the vehicle. The left and right vehicle lamps 1 have substantially the same configuration except that they have symmetrical structures. Note that each direction shown in FIG. 1 may be a direction relative to the vehicle when the vehicle lamp 1 is attached to the vehicle.

[0014] The vehicle lamp 1 includes a lamp body 2 having an opening on the front side of the vehicle, and a light-transmitting cover 3 that covers the opening of the lamp body 2. A lighting unit 4 is housed in a lamp chamber 7 formed by the lamp body 2 and the light-transmitting cover 3.

[0015] The lighting unit 4 is configured to form a light distribution pattern by emitting light toward the outside (forward) of the vehicle. Although not shown, the lighting unit 4 includes a light source that emits light and an optical system. The light source may include a light-emitting element such as an LED (Light Emitting Diode), an LD (Laser Diode), or an organic EL (Electro Luminescence). The optical system may include at least one of a reflector configured to reflect light emitted from the light source toward the front of the lighting unit 4, and a lens configured to refract light directly emitted from the light source or light reflected by the reflector.

[0016] The lighting unit 4 is attached to the vehicle lamp 1 via a first bracket portion 5a extending above the lighting unit 4 and a second bracket portion 5b extending below the lighting unit 4. The first bracket portion 5a has a screw hole at a predetermined position. The lamp body 2 also has a screw support portion 21 at a position overlapping the screw hole in the front-rear direction. The screw support portion 21 is, for example, a cylindrical member extending in the front-rear direction, and is provided so as to communicate between the inside and outside of the lamp body 2.

[0017] An optical axis adjustment screw 100 is inserted into the screw support portion 21 from the outside of the lamp body 2. The optical axis adjustment screw 100 is rotatably supported by the screw support portion 21. The optical axis adjustment screw 100 is threaded into a screw hole in the first bracket portion 5a. The structure of the optical axis adjustment screw 100 will be described in detail in a later paragraph.

[0018] A pivot portion 6 is provided at a predetermined position on the second bracket portion 5b. The pivot portion 6 is a member that protrudes rearward from the second bracket portion 5b. A ball for a ball joint is provided at the rear end of the pivot portion 6. The lamp body 2 also has a joint receiving portion 23 at a position that overlaps with the pivot portion 6 in the front-to-rear direction. The joint receiving portion 23 is a member that protrudes forward from the lamp body 2 and has a ball receiving portion at its end. The ball of the pivot portion 6 is rotatably connected to the ball receiving portion of the joint receiving portion 23.

[0019] The first bracket portion 5a, the second bracket portion 5b, the optical axis adjustment screw 100, the pivot portion 6, and the joint receiving portion 23 are part of an aiming mechanism for adjusting the optical axis direction of the lighting unit 4. By rotating the optical axis adjustment screw 100, the lighting unit 4 is tilted with the ball of the pivot portion 6 as a fulcrum, and the optical axis of the lighting unit 4 can be adjusted in the up-down direction (vertical direction). Although not shown in the figures, the lighting unit 4 is connected to two optical axis adjustment screws 100 lined up horizontally via bracket portions. Therefore, the optical axis of the lighting unit 4 can also be adjusted in the horizontal direction.

[0020] The vehicle lamp 1 is not limited to the above example in other configurations as long as it is provided with at least the optical axis adjustment screw 100. Conventionally known configurations may be adopted for the other configurations except for the optical axis adjustment screw 100.

[0021] (Optical axis adjustment screw) The optical axis adjustment screw 100 is a member for adjusting the light emission direction of the vehicle lamp 1, i.e., the optical axis of the lighting unit 4. The optical axis adjustment screw 100 is made of resin, but may contain metal in part. The structure of the optical axis adjustment screw 100 will be described in detail below with reference to Figs. 2 and 3.

[0022] 2 is a schematic diagram (side view) showing an optical axis adjustment screw 100 according to an embodiment of the present disclosure. As shown in FIG. 2, the optical axis adjustment screw 100 includes a threaded portion 103, a connecting portion 104, a support shaft portion 105, and an engagement portion 106 between a front end portion 101 and a rear end portion 102.

[0023] The screw portion 103 is formed on the front end portion 101 side. The screw portion 103 is provided with a screw groove that screws into the screw hole of the first bracket portion 5a. The support shaft portion 105 is formed on the rear end portion 102 side. The support shaft portion 105 is supported by the screw support portion 21. The support shaft portion 105 may be provided with a seal member (e.g., an O-ring) to prevent moisture from entering the lamp chamber 7. The connecting portion 104 is formed between the screw portion 103 and the support shaft portion 105.

[0024] The engaging portion 106 protrudes from the connecting portion 104 so as to extend from the screw portion 103 side toward the support shaft portion 105 side. The engaging portion 106 is formed so as to be able to come into contact with the front end portion of the screw support portion 21 when the support shaft portion 105 is supported by the screw support portion 21.

[0025] The engaging portion 106 can elastically deform in a direction toward and away from the connecting portion 104. When the optical axis adjustment screw 100 is inserted into the screw support portion 21, the engaging portion 106 is pressed against the inner wall of the screw support portion 21 and elastically deforms in a direction toward the connecting portion 104. Then, when the entire engaging portion 106 has passed through the screw support portion 21, the engaging portion 106 elastically returns to its original position in a direction away from the connecting portion 104. As a result, the rear end of the engaging portion 106 abuts against the front end of the screw support portion 21. This mechanism prevents the optical axis adjustment screw 100 from coming off the lamp body 2. Note that the number of engaging portions 106 is not particularly limited, but from the viewpoint of reducing the load applied to each engaging portion 106, it is preferable to provide a plurality of engaging portions 106 in pairs at positions facing each other across the connecting portion 104.

[0026] Fig. 3 is a schematic diagram showing the internal structure of the optical axis adjustment screw 100 according to an embodiment of the present disclosure. Region X shown in Fig. 3 shows the internal structure of the support shaft portion 105. As shown in region X, the support shaft portion 105 includes a skin layer 110 and a foam layer 120. Note that other portions of the optical axis adjustment screw 100, such as the threaded portion 103 and the connecting portion 104, may also include a skin layer 110 formed on the surface thereof and a foam layer 120 formed inside the skin layer 110.

[0027] The optical axis adjustment screw 100 including the skin layer 110 and the foam layer 120 can be manufactured by, for example, micro-injection foam molding using a supercritical fluid. Specifically, it can be manufactured by injecting a single-layer melt obtained by uniformly mixing and dispersing a supercritical fluid (e.g., nitrogen or carbon dioxide) into a plasticized resin into a mold cavity while controlling the pressure and temperature. The resin is not particularly limited, but thermoplastic resins such as polycarbonate resin, polypropylene resin, acrylic resin, ASA (Acrylate Styrene Acrylonitrile) resin, and ABS (Acrylonitrile Butadiene Styrene) resin can be used. Note that the manufacturing method of the optical axis adjustment screw 100 is not limited to micro-injection foam molding, and other conventionally known manufacturing methods may also be used.

[0028] The skin layer 110 is formed on the surface of the support shaft portion 110. The skin layer 110 is a layer that is substantially free of air bubbles. Note that "substantially free of air bubbles" means, for example, that the skin layer 110 does not contain air bubbles of a size and amount that would significantly affect the weight and mechanical strength of the skin layer 110. The thickness of the skin layer 110 is not particularly limited, but is preferably, for example, 10 μm or more and 1000 μm or less.

[0029] The foam layer 120 is a layer formed inside the skin layer 110. The foam layer 120 contains a plurality of bubbles 121. By including a plurality of bubbles 121 in the foam layer 120, the lightness of the optical axis adjustment screw 100 is improved.

[0030] The average diameter of the bubbles 121 in the foam layer 120 is 10 μm or more and 100 μm or less from the viewpoint of achieving both the necessary mechanical strength and light weight. From the same viewpoint, the average diameter of the bubbles 121 is, for example, preferably 20 μm or more and 90 μm or less, and more preferably 30 μm or more and 80 μm or less. Note that the "average diameter of bubbles" refers to the average value of the diameters of any 20 bubbles when a cross section is observed using a scanning electron microscope (SEM).

[0031] From the viewpoint of suppressing a decrease in mechanical strength, the maximum diameter of the bubbles 121 in the foamed layer 120 is, for example, preferably 100 μm or less, more preferably 60 μm or less, and even more preferably 40 μm or less.

[0032] The average diameter and maximum diameter of the bubbles 121 can be controlled, for example, by adjusting the injection speed. Usually, a fast injection speed reduces the average diameter and maximum diameter of the bubbles 121, and a slow injection speed increases the average diameter and maximum diameter of the bubbles 121. The average diameter and maximum diameter of the bubbles 121 can also be controlled by adjusting the temperature and pressure inside the mold.

[0033] From the viewpoint of reducing weight and suppressing the occurrence of sink marks, the foaming ratio of the foam layer 120 is preferably, for example, 1.0% or more, more preferably 1.5% or more, and even more preferably 2.0% or more. From the viewpoint of ensuring mechanical strength, the foaming ratio of the foam layer 120 is, for example, preferably 10.0% or less, more preferably 5.0% or less, and even more preferably 4.0% or less. The "foaming ratio" (%) is a value indicating the weight loss due to foaming, and is calculated, for example, by the formula "{(weight before foaming - weight after foaming) / (weight before foaming)}×100".

[0034] Region Y in Figure 3 shows the internal structure of the engagement portion 106 and part of the internal structure of the connecting portion 104. As shown in region Y, the vicinity of the end of the engagement portion 106 on the threaded portion 103 side, i.e., the vicinity of the base of the engagement portion 106, is formed only by the skin layer 110 and does not include the foam layer 120. The vicinity of the base of the engagement portion 106 is prone to damage because a load is concentrated thereon when preventing the optical axis adjustment screw 100 from coming off from the lamp body 2. In the optical axis adjustment screw 100 according to this embodiment, the vicinity of the base of the engagement portion 106 is formed only by the skin layer 110, thereby increasing the mechanical strength compared to when the foam layer 120 is included, and making the vicinity of the base of the engagement portion 106 less susceptible to damage.

[0035] To form the base vicinity of the engaging portion 106 using only the skin layer 110, it is necessary to appropriately set the injection conditions, such as the injection speed, temperature, or pressure, and the thickness of the base vicinity of the engaging portion 106. The thickness d of the base vicinity of the engaging portion 106 is, for example, preferably 0.8 mm or more and 2.4 mm or less, more preferably 1.0 mm or more and 2.0 mm or less, and even more preferably 1.1 mm or more and 1.8 mm or less.

[0036] The mold used for injection molding has vent holes in multiple locations, but it is preferable to provide a vent hole that is larger than other locations in the mold in the portion of the mold that corresponds to the end on the rear end 102 side of engaging portion 106. With this configuration, even if the thickness d near the base is made small, it becomes easy to fill the mold with resin up to the tip.

[0037] The internal structure of the connecting portion 104, like the support shaft portion 105, has a skin layer 110 on the surface and a foam layer 120 inside the skin layer 110. Since the connecting portion 104 is thinner than the support shaft portion 105 and is more likely to be subjected to load, from the perspective of ensuring mechanical strength, it is preferable to make the average diameter and maximum diameter of the bubbles 121 in the foam layer 120 smaller than those of the support shaft portion 105. In general, the later a portion is filled into the mold, the larger the size of the bubbles tends to be. Therefore, for example, by filling the connecting portion 104 after the support shaft portion 105 during injection, the average diameter and maximum diameter of the bubbles 121 in the foam layer 120 of the connecting portion 104 can be made smaller than those of the support shaft portion 105.

[0038] The present invention is not limited to the above-described embodiments, and can be freely modified, improved, etc. The material, shape, dimensions, numerical values, form, number, location, etc. of each component in the above-described embodiments are arbitrary and not limited as long as the present invention can be achieved. [Explanation of symbols]

[0039] 1: Vehicle lighting fixtures 2: Lamp body 3:Translucent cover 4: Lighting unit 5a: First bracket part 5b: Second bracket part 6: Pivot part 7: Lamp room 21: Screw support part 23: Joint support 100: Optical axis adjustment screw 101: Front end 102: Rear end 103: Threaded part 104:Connection part 105: Support shaft part 106: Engagement part 110: Skin layer 120: Foam layer 121: Bubbles d: thickness

Claims

1. A resin optical axis adjustment screw for adjusting the light emission direction of a vehicle lamp, a skin layer formed on the surface of the optical axis adjusting screw; a foam layer formed inside the skin layer and containing a plurality of bubbles; the average diameter of the bubbles in the foamed layer is 10 to 100 μm; The optical axis adjustment screw further includes: A threaded portion formed on the front end side; a support shaft portion formed on a rear end side and supported by a screw support portion of the vehicle lamp; a connecting portion formed between the threaded portion and the support shaft portion; an engaging portion that protrudes from the connecting portion so as to extend from the threaded portion side to the support shaft portion side, and that can come into contact with the screw support portion when the support shaft portion is supported by the screw support portion, an end portion of the engagement portion on the side of the threaded portion is formed only by the skin layer and does not include the foam layer; Optical axis adjustment screw.

2. The foaming rate of the foam layer is 1 to 10%. The optical axis adjusting screw according to claim 1 .

3. A vehicle lamp comprising the optical axis adjusting screw according to claim 1 or 2.

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