JP6738217B2 - Method for manufacturing outer lens for vehicle lamp and vehicle lamp - Google Patents

Description

The present invention relates to a method for manufacturing an outer lens used for a vehicle lamp and a vehicle lamp.

Conventionally, an outer lens that is located on the outermost side of a vehicular lamp and constitutes a transmission optical path of emitted light is generally formed of polycarbonate that has excellent impact resistance while ensuring transparency. However, polycarbonate is inferior in weather resistance and is likely to be scratched, and in particular, it undergoes discoloration (yellowing) upon receiving ultraviolet rays of sunlight, resulting in a decrease in transmittance and a change in color tone of transmitted light.

In order to solve this problem, the base material of the outer lens is formed of polycarbonate, which has various properties such as impact resistance, heat resistance and transparency, and the outer surface of the base material (the surface exposed to sunlight) has weather resistance, A layer of PMMA (polymethylmethacrylate:acrylic) having good properties such as impact resistance, water resistance and transparency is provided, and SiO having good properties such as scratch resistance and abrasion resistance is provided on the outer surface of the PMMA layer. _{There is one in which two} layers are provided to form an outer lens having a three-layer structure (see Patent Document 1).

In addition, the body of the lens (outer lens) is made of hard acrylic, which has higher transmittance and higher heat resistance than polycarbonate, and a protective film made of soft acrylic, which has excellent chemical cracking and impact resistance, is formed on the lens body. There is (see Patent Document 2).

JP-A-2009-26646 Japanese Patent Laid-Open No. 11-345503

By the way, each of the outer lenses having the above structure has a multi-layer structure, so that the number of steps in the manufacturing process increases, which causes an increase in manufacturing cost.

In addition, the material cost of the material forming each layer increases due to the multi-layer structure, which also increases the manufacturing cost.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing an outer lens for a vehicle lamp, which has extremely high transmittance and extremely low manufacturing cost. Another object of the present invention is to provide a vehicular lamp using an outer lens for vehicular lamps, which has an extremely high transmittance and an extremely low manufacturing cost.

In order to solve the above-mentioned problem, the invention described in claim 1 of the present invention is formed by a housing having an opening, an outer lens made of a transparent resin covering the opening, and the housing and the outer lens. A vehicular lamp including a light source unit arranged in a lamp chamber, wherein the outer lens is located in front of an irradiation direction of the vehicular lamp, a design portion covering the opening, and a peripheral portion of the design portion. An annular peripheral side portion that extends in a plate shape toward the housing side substantially perpendicularly to the plate surface direction of the design portion along a peripheral edge, and the design along the peripheral end portion from the peripheral end portion of the peripheral side portion. An annular flange portion that extends in a plate shape in the plate surface direction of the portion, and an annular seal rib portion that extends in a plate shape in the plate surface direction of the peripheral side portion from the peripheral end portion of the flange portion along the peripheral end portion. The design portion, the peripheral side portion, the flange portion and the seal rib portion are made of the same material layer made of a transparent acrylic resin, and the design portion, the peripheral side portion, the flange portion and the seal rib portion are , Integral, of the annular flange portion, while the gate trace remains on the outer periphery of the flange portion extending in the longitudinal direction of the design portion, the gate trace does not remain in the design portion, the average of the design portion The wall thickness is 3 mm or more, and the minimum distance is 3.0 mm to 4.0 mm, and the average thickness of the peripheral side portion and the flange portion is 70% or less of the average thickness of the design portion, A skin layer having a thickness of 1 mm or more and mechanically strong with respect to the core layer inside the design portion is formed on the surface of the design portion .

Moreover, the invention described in claim 2 of the present invention is characterized in that, in claim 1, the light source unit is a fog lamp using a light emitting diode as a light source .

In addition, the invention described in claim 3 of the present invention is characterized in that, in claim 2, the invention is installed at a position lower than a headlamp of a vehicle .

According to the present invention, the outer lens comprises a plate-shaped design portion, an annular peripheral side portion extending from the peripheral edge of the design portion along the peripheral edge in a plate shape substantially perpendicular to the plate surface direction of the design portion, and the peripheral side. An annular flange portion extending in a plate shape from the peripheral end portion of the flange portion in the plate surface direction of the design portion, and a plate surface of a peripheral side portion from the peripheral end portion of the flange portion to the peripheral end portion Direction has a plate-like annular seal rib portion, and the molding die has a gate connected to the cavity forming the seal rib portion forming the seal rib portion, and the gate forms the flange portion forming the flange portion. An acrylic resin was used as the injection molding material, with the structure in which the seal rib was formed in a direction perpendicular to the surface direction of the molding region on the extension line of the region.

As a result, the outer lens molded by injection molding has a mechanically strong skin layer formed on the surface during injection molding. It can be used as an outer lens that is affected by the natural environment such as heat and heat, and is subjected to vibrations and intermittent impacts and hits flying objects such as stones and sand that have flew away.

As a result, it is possible to provide an outer lens for a vehicle lamp and a vehicle lamp having an extremely high transmittance and an extremely low manufacturing cost.

It is a longitudinal cross-sectional view of a vehicular lamp using an outer lens. It is the perspective view which looked at the outer lens from the front slanting upper part. It is a front view of an outer lens. FIG. 4 is a sectional view taken along line AA of FIG. 3. FIG. 4 is a sectional view taken along line BB of FIG. 3. It is a sectional view of an injection mold. It is a fragmentary sectional view of an injection mold. Similarly, it is a partial cross-sectional view of an injection molding die. It is a sectional view of an injection-molded article (outer lens). It is a table of the test result of a spray test.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 10 (the same portions are denoted by the same reference numerals). Since the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are attached, but the scope of the present invention particularly limits the present invention in the following description. The present invention is not limited to these embodiments, unless otherwise stated.

FIG. 1 is a vertical cross-sectional view of a vehicular lamp using the outer lens of the present invention, FIG. 2 is a perspective view of the outer lens as seen obliquely from the front upper side, FIG. 3 is a front view of the outer lens, and FIG. 4 is A of FIG. -A sectional view, FIG. 5 is a BB sectional view of FIG. In the present embodiment, a front fog lamp will be described as an example of a vehicle lamp.

In a vehicle lamp (hereinafter, simply referred to as “lamp”) 1, a housing 2 having an opening and an outer lens 10 provided so as to cover the opening of the housing 2 form a lamp chamber 3 which is a closed space. A light source unit 6 having an optical system including a light source 4 and a projection lens 5 is housed in the chamber 3. The light source 4 uses a light emitting diode and is attached to a heat sink 7 for radiating heat generated when the light source is turned on. The vehicular lamp 1 is installed at a position below a headlamp, such as in a bumper on the front side of the vehicle (not shown).

Then, the light emitted from the light source 4 is condensed by the projection lens 5 and emitted through the outer lens 10 to the outside of the lamp chamber 3. That is, the outer lens 10 is located in front of the vehicular lamp in the irradiation direction.

Next, the outer lens 10 will be described.

The outer lens 10 includes a horizontally long plate-shaped design portion 11 that is long in one direction, and an annular peripheral side portion that extends from the peripheral edge of the design portion 11 along the peripheral edge in a plate shape substantially perpendicular to the plate surface direction of the design portion 11. 12, an annular flange portion 13 extending in a plate shape from the peripheral end portion of the peripheral side portion 12 to the outer side in the plate surface direction of the design portion 11 along the peripheral end portion, and the peripheral end portion of the flange portion 13 from the peripheral end portion. It has an annular seal rib portion 14 that extends in a plate shape along the end portion in the plate surface direction of the peripheral side portion 12.

The outer lens 10 has an optical function of transmitting the light emitted from the light source unit housed in the lamp chamber and emitting the light to the outside of the lamp chamber. Therefore, in order to minimize the transmission loss of light when transmitting through the outer lens 10 and improve the light utilization efficiency, it is required to have a high transmittance. In particular, the design portion 11 serving as a light transmission path is required to have high transmittance.

At the same time, the outer lens 10 is directly exposed to the environment outside the vehicle when the lamp is mounted on the vehicle, and thus is affected by the natural environment such as ultraviolet rays and heat of sunlight, and when the vehicle is traveling, continuous vibration and intermittent vibrations occur. There is a concern that stones, sand, and other flying objects that have flew away may be hit and damaged due to impact.

Therefore, the outer lens 10 is also required to have various mechanically excellent properties such as impact resistance, scratch resistance, and abrasion resistance.

In the present invention, the outer lens 10 which is optically and mechanically excellent is realized by giving priority to the transmittance with respect to the outer lens 10 and further improving mechanical characteristics.

Specifically, by injection molding using an acrylic resin, which has a higher transmissivity than polycarbonate resin, as a molding material, it is possible to realize an outer lens that is mechanically superior to the outer lens formed of a conventional acrylic resin.

Next, a method of molding the outer lens will be described. FIG. 6 is a diagram showing a mold clamping state of a molding die for injection molding the outer lens.

In the mold, a fixed mold 30 and a movable mold 35 are arranged to face each other with a parting surface 40 in between. The cavity formed by the fixed mold 30 and the movable mold 35 is a region (design part molding region) 50 for molding the design part of the molded product (outer lens), and a region (peripheral side part molding) for molding the peripheral side part. Region 51, a region for forming a flange portion (flange portion forming region) 52, and a region for forming a seal rib portion (seal rib portion forming region) 53.

The gate 41 extends in a direction perpendicular to the surface direction of the seal rib portion molding region 53 on the extension line of the flange portion molding region 52 of the seal rib portion molding region 53. The gate 41 is located in the seal rib portion forming region 53 corresponding to the center position in the longitudinal direction of the horizontally long design portion forming region 50. The injection position from the gate 41 in the outer lens 10 is located at the center in the left-right direction of the paper surface in FIG. 3 and above the design portion. No gate is provided in the design portion molding region 50. Therefore, in the outer lens 10, a gate mark (not shown) is left outside the flange portion 13.

Further, the gate 41 is connected to a concave nozzle touch portion (molten resin injection port) 44 via the runner 42 and the sprue 43. The nozzle touch portion 44 is brought into contact with the tip of a nozzle 46 of a cylinder 45 of a molding machine during injection molding, and molten resin supplied from the molding machine is injected into the molds 30 and 35 through the nozzle 46.

At the time of injection molding, acrylic resin (Telpet Asahi Kasei Corp.) was used as a molding material, and it was put into the cylinder 45 after being pre-dried for 2 to 6 hours. The set temperature of the molten acrylic resin in the cylinder was set to a temperature near the upper limit of the recommended molding conditions. By setting the temperature of the molten resin, especially the temperature on the nozzle side, to be high (a temperature near the upper limit of the recommended molding conditions), the fluidity was increased and the time for filling the resin in the cavity was shortened. If the temperature exceeds the temperature of the recommended molding conditions, there is a high possibility that the material will be denatured and burned, which is not preferable.

Then, the molten resin injected from the nozzle 45 of the molding machine and injected into the sprue 43 of the fixed mold 30 is sent to the gate 41 through the sprue 43 and the runner 42.

As shown in FIG. 7, the molten resin 47 sent to the gate 41 is injected at a predetermined flow rate from the gate 41 to the seal rib portion molding region 53 of the cavity connected to the gate 41. At this time, the temperature on the nozzle side is set high (a temperature near the upper limit of the recommended molding condition) to enhance the fluidity, so that the resin injected into the cavity via the gate 41 also has a low temperature on the nozzle side (recommended molding). The flow velocity will be faster than when the temperature is near the lower limit of the condition).

The molten resin 47 injected from the gate 41 into the seal rib portion molding region 53 at a predetermined flow velocity directly hits the surface 51a on the movable mold 35 side that forms the peripheral side portion molding region 51 located on the front surface, and thereafter, As shown in FIG. 8, the flow is arranged in the circumferential side molding region 51 while spreading in the longitudinal direction to direct the flow toward the design portion molding region 50, and flows in the design portion molding region 50 with a uniform flow in the longitudinal direction. Then, it flows sequentially through the peripheral side portion forming region 51 and the flange portion forming region 52, and reaches the seal rib portion forming region 53. As a result, the molten resin 47 is filled in the entire cavity.

At this time, in the process in which the molten resin 47 flows in the cavity, the so-called skin layer 48 is formed by instantaneously solidifying the layer that is at a lower temperature than the molten resin 47 and is in contact with the cavity forming surface. The skin layer 48 is a layer having a high resin density and a mechanically strong layer with respect to the inner core layer 49 by being made amorphous.

As a result, the molded product (outer lens 10) taken out from the molds 30 and 35 has a mechanically strong skin layer 48 having an appropriate thickness on the entire surface as shown in FIG.

As described above, by increasing the temperature of the molten resin and increasing the temperature difference from the molding die, the time until the core layer is solidified is lengthened to secure the thickness of the skin layer, and at the same time the gate is arranged. By setting the position to an appropriate position of the cavity, it is arranged so that the molten resin flowing in the design region molding region 50 flows uniformly, and a strong skin layer in which the uniformity of amorphization is improved. The outer lens having is realized.

When the vehicular lamp 1 is a front fog lamp, it is fixed to the front of the vehicle. When observing the front fog lamp from the front of the vehicle, the light emitted from the light source unit 6 is emitted toward the front of the vehicle through the design portion of the outer lens 10 which is the front. At this time, the outer lens 10 is formed by integrally molding the design portion molding region 50, the peripheral side portion molding region 51, the flange portion molding region 52, and the seal rib portion molding region 53 of the cavity, which are made of the same acrylic resin. In addition, the manufacturing cost can be reduced as compared with the case of laminating different materials or isomers of the same material. Therefore, it is possible to realize a vehicular lamp capable of performing bright illumination in which attenuation of light emitted through the design portion is suppressed.

Next, the wall thickness of the outer lens 10, that is, the distance between the dies of the cavity will be described.

The thickness of the design portion 11 of the outer lens 10 (distance between the dies in the design portion molding region 50 of the cavity) is 3.0 mm or more. As a conventional outer lens made of polycarbonate for a headlight or a front fog lamp, a lens having a wall thickness of about 2.0 mm (about 1.8 mm to 2.2 mm) is generally used. By making the design part thicker, it is possible to make the design part crack and to increase the damage, even if flying objects such as stones and sand that have flew during traveling of the vehicle are hit and damaged. Can be prevented. At the same time, the problem of weld, which will be described later, can be reduced. Particularly, not only the average thickness of the entire design portion 11 is set to 3.0 mm or more, but also the thickness of the thinnest portion in the design portion 11 is 3.0 mm or more, that is, both the average thickness and the minimum thickness are 3 mm. By setting the thickness to be 0.0 mm or more, the mechanical strength can be further improved.

The peripheral side portion 12 of the outer lens 10 (distance between the molds of the peripheral side portion molding region 51 of the cavity), the flange portion 13 (flange portion molding region 52) and the seal rib portion 14 (seal rib portion molding region 53) have the same thickness. Is thinner than 3.0 mm. Specifically, the peripheral side portion 12 and the flange portion 13 have a wall thickness of 2.0 mm. The thickness of the seal rib portion 14 is 2.0 mm on the flange portion 13 side and 1.9 mm on the tip end side, and is gradually reduced.

The gate 41 is located outside the flange portion molding region 52 as shown in FIGS. 6 and 7. As described above, the molten resin 47 is injected from the gate 41 into the cavity. The molten resin 47 injected from the gate 41 into the seal rib portion molding region 53 at a predetermined flow velocity directly hits the surface 51a on the movable mold 35 side that forms the peripheral side portion molding region 51 located on the front surface, and thereafter, As shown in FIG. 8, it is directed to the inside of the peripheral side molding region 51 and the design region molding region 50. At this time, since the distance between the molds of the peripheral side molding region 51 and the flange portion molding region 52 is formed thinner than the distance between the molds of the design portion molding region 50, the peripheral side molding that is formed thinly. The molten resin 47 filled in the thicker design portion molding region 50 advances earlier than the region 51 and the flange portion molding region 52. Specifically, the die-to-die distance between the peripheral side molding region 51 and the flange portion forming region 52 is 2.0 mm, and the die-to-die distance of the design portion forming region 50 is 3.5 mm.

The distance between the molds of the peripheral side molding region 51 and the flange molding region 52 is set between 50% and 70% based on the distance between the molds of the design portion molding region 50. The distance between the molds of the peripheral side molding region 51 and the flange molding region 52 is set to be thicker than 1.0 mm. When the thickness is less than 1.0 mm, the strength of the outer lens as a whole is lowered. If it is less than 50%, the difference in relative thickness of the peripheral side portion 12 and the flange portion 13 with respect to the design portion 11 becomes too large, and the impact of the peripheral side portion 12 and the flange portion 13 is concentrated, and the flange portion is destroyed. It will be easier. If it exceeds 70%, the molten resin 47 injected into the peripheral side molding region 51 and the flange molding region 52 wraps around the design portion molding region 50. Therefore, weld is likely to occur in the design portion 11, which is not preferable. If the ratio is between 50% and 70%, the molten resin 47 injected from the outside of the flange portion molding region 52 through the gate 41 will flow around the entire circumference of the peripheral side portion molding region 51 and the flange portion molding region 52. First, the entire design portion molding region 50 is filled. That is, the filling into the entire design portion molding region 50 having a small flow resistance proceeds first, and the circumferential side portion molding region 51 and the flange portion molding region 52 are entirely filled with the design portion molding region 50. Only after 50 injections. Therefore, although welds may occur in the peripheral side portion molding region 51 and the flange portion molding region 52, they are less likely to occur in the design portion molding region 50.

Further, the distance between the molds of the peripheral side molding region 51 and the flange portion molding region 52 is more preferably between 61% and 67% based on the distance between the molds of the design portion molding region 50, and The minimum distance of the partial molding region 50 is set to 3.0 mm to 4.0 mm. If the wall thickness of the design portion 11 of the outer lens, which is a molded product, is made thicker than 4.0 mm, the weight becomes heavy, which is not preferable. This is because if the thickness is less than 3.0 mm, the resistance to scratches becomes poorer, and at the same time, the thickness of the peripheral side portion 12 and the flange portion 13 becomes relatively thin and the overall strength decreases.

Further, in the design portion 11, the skin layer 48 of the acrylic resin is uniformly formed on the surface by finishing the filling of the peripheral side portion molding region 51 and the flange portion molding region 52 to the entire circumference. You can In other words, the molten resin 47 is injected so that welds do not occur in the design part 11, so that the skin layer formed in the design part 11 has a peripheral side forming region 51 or a flange forming region in which the weld is formed. Since the design portion 11 is formed more uniformly than the skin layer in 52 and the design portion 11 has a large thickness, the mechanical properties can be made excellent.

Next, for the test piece of the outer lens manufactured by the above method, in order to confirm the resistance to mechanical deterioration, a spray test using a spray gun was performed, and the change rate of transmission and the change rate of diffusion after the test were measured. I examined it, and I explain below.

The spray gun of the test equipment was equipped with a nozzle having a diameter of 1.3 mm, an operating pressure of 6.0 bar, and a liquid flow rate of 0.24 per minute. Under this operating condition, the fan-shaped pattern formed on the surface subject to deterioration at a distance of 380 mm ± from the nozzle has a diameter of 170 mm.

The composition of the test mixture used silica sand having a Mohs hardness of 7, a particle size of 0 to 0.2 mm, a substantially normal distribution, and an angular coefficient of 1.8 to 2. In the case of a mixture of 25 g of silica sand per liter of water, water having a hardness not exceeding 205 g/mm ³ was used for atomization.

In the test, the outer surface of the test piece is sprayed once or more with the silica sand produced as described above. The spray is applied almost at right angles to the test surface of the test piece.

Check for degradation by placing one or more glass samples as a reference near the test sample being tested. The mixture is sprayed until the variation in diffusion on the glass sample measured by the method described below is Δd=(T5-T4)/T2≦0.0250±0.0025.

The method of measuring a glass sample is to limit the beam of the collimator K with a half-diffusion β/2=17.4×10 ⁻⁴ rd with a diaphragm D _T having a 6 mm aperture and place the sample stage against it.
The diaphragm D _T and the light receiver R are connected by a converging achromatic lens L ₂ corrected for spherical aberration. The diameter of the lens L ₂ is set such that the light diffused by the glass sample in the cone having the half-vertical angle β/2=14° is not focused by the diaphragm.
An annular diaphragm D _D having angles a/2=1° and a _max /2=12° is placed in the lens L ₂ image focal plane.
An opaque central portion of the diaphragm is required to eliminate light coming directly from the light source. It shall be possible to move the central part of the diaphragm away from the beam of light and return it exactly to its original position.
The distance of L ₂ D _T and the focal length F ₂ ¹ of the lens L ₂ shall be chosen so that the image of D _T completely covers the light receiver R.
If the initial incident flux is 1000 units, then the absolute accuracy of each reading shall be greater than 1 unit.
The measurement shall measure the following values.

The test results are shown in the table of FIG.

Regarding the three test pieces, the test pieces were formed into a flat plate shape by using the acrylic resin described in the embodiment and setting the temperature of the molten resin, particularly the nozzle side temperature, to be high (a temperature near the upper limit of the recommended molding conditions). No test was performed on the surface of the test piece. The rate of change in transmission Δt=(T2−T3)/T2 after the test is 0.030 (3%), 0.027 (2.7%), and 0.028 (2.8%) after the test. Met. This result indicates that, for example, when the transmittance of acrylic is 93% and the transmittance of polycarbonate is 86%, the transmittance of acrylic after the spray test also exceeds the transmittance of polycarbonate.

That is, since the outer lens molded by injection molding has a mechanically strong skin layer formed on the surface during injection molding, it is possible to maintain a transmittance far exceeding that of polycarbonate even in a spray test. As a result, it flew away without being subjected to a strengthening treatment such as a hard coat on the surface as it was in the past, as it was affected by the natural environment such as ultraviolet rays and heat of sunlight, as well as subjected to vibration and intermittent impact. It can also be used as an outer lens for vehicles that hit flying objects such as stones and sand.

As a result, the outer lens of the vehicular lamp having an extremely high transmittance and an extremely low manufacturing cost is realized.

In addition, although the outer lens of the front fog lamp has been described as an example in the above embodiment, the present invention is not limited to this. It can also be applied to the outer lens of vehicle headlights.

DESCRIPTION OF SYMBOLS 1... Vehicle lamp 2... Housing 3... Lamp room 4... Light source 5... Projection lens 6... Light source unit 7... Heat sink 10... Outer lens 11... Design part 12... Circumferential side part 13... Flange part 14... Seal rib part 30... Fixed Mold 35... Movable mold 40... Parting surface 41... Gate 42... Runner 43... Sprue 44... Nozzle touch part 45... Cylinder 46... Nozzle 47... Molten resin 48... Skin layer 49... Core layer 50... Design part molding area 51... Peripheral side forming region 52... Flange forming region 53... Seal rib forming region

Claims (3)

A housing having an opening, and the outer lens made of a transparent resin for covering the opening, wherein a vehicle both lamp that includes a light source unit disposed in a lamp chamber formed by the outer lens and the housing,
The outer lens includes a design portion which is located in the irradiation direction front of the vehicle both lamp, cover the opening,
An annular peripheral side portion extending in a plate shape from the peripheral edge of the design portion toward the housing side substantially perpendicular to the plate surface direction of the design portion along the peripheral edge,
An annular flange portion extending in a plate shape in the plate surface direction of the design portion along the peripheral end portion from the peripheral end portion of the peripheral side portion,
A ring-shaped seal rib portion extending in a plate shape from the peripheral end portion of the flange portion along the peripheral end portion in the plate surface direction of the peripheral side portion,
The design portion, the peripheral side portion, the flange portion and the seal rib portion are made of the same material layer made of a transparent acrylic resin,
The design portion, the peripheral side portion, the flange portion and the seal rib portion are integral,
Of the annular flange portion, with a gate trace on the outer periphery of the flange portion extending in the longitudinal direction of the design portion, no gate trace remains on the design portion,
The average thickness of the design portion is 3 mm or more , and the minimum distance is 3.0 mm to 4.0 mm ,
The average thickness of the peripheral side portion and the flange portion is 70% or less of the average thickness of the design portion, and 1 mm or more ,
A vehicle lamp characterized in that a skin layer that is mechanically strong with respect to the core layer inside the design portion is formed on the surface of the design portion . The vehicle light according to claim 1, wherein the light source unit is a fog lamp using a light emitting diode as a light source . The vehicle lamp according to claim 2, wherein the vehicle lamp is installed at a position lower than a headlamp of the vehicle.