JP7569718B2 - Injection Molding - Google Patents

Description

This invention relates to injection molded products, particularly injection molded products with ribs.

In injection molded products, ribs are sometimes provided at the folded portion to prevent deformation during molding. For example, in Patent Document 1, a mounting leg is formed to protrude from the end of the opening of the lamp body, and a reinforcing rib is provided in the narrow space between the lamp body and the mounting leg.

Japanese Patent Application Publication No. 10-241408

However, in Patent Document 1, the reinforcing ribs that connect the lamp body and the mounting legs are formed over the entire narrow space up to the extended end of the mounting legs, which causes a problem of a large amount of thermal shrinkage during injection molding. This is not limited to lamp bodies; for example, when the area where the ribs are provided constitutes a specific design or function, such as a design surface with a detailed emblem or an optical component that forms a light distribution, the molding dimensions are required to be more strict, so deformation due to thermal shrinkage during molding is a serious problem.

The present invention was made in consideration of this, and provides an injection-molded product with ribs that can suppress deformation during molding while ensuring reinforcing function.

In order to solve the above problems, in one aspect of the configuration of the present disclosure, an injection molded product is configured to include a design part that is recessed on the back surface and has a predetermined shape that provides a required appearance or function, and a non-design part that is adjacent to the design part across a narrow space by being folded back continuously from the periphery of the design part, and a rib is provided in the narrow space, and the rib includes a first rib that crosses the adjacent direction and connects the design part and the non-design part, and a second rib that is integrally formed with the first rib and formed in a vertical wall shape on the non-design part up to the extended end of the non-design part. According to this aspect, the slightly protruding vertical wall rib provided up to the extended end has the effect of sticking to the mold during cooling during injection molding and suppressing deformation, so that the first rib improves the rigidity of the injection molded product, and the second rib suppresses deformation during molding. A good balance between improved rigidity and suppression of deformation during molding can be ensured.

In one embodiment, the second rib is configured to be formed with a height not exceeding 3 mm. Even a slightly protruding vertical rib can stick to the mold and suppress deformation during molding, so by making the height 3 mm or less, the deformation suppression effect during molding is ensured while also suppressing the amount of heat required for molding.

In one embodiment, the second rib is configured to be formed at a substantially constant height up to the extended end of the non-design portion.

In one embodiment, the second rib is configured to decrease in height toward the extending end of the non-design portion. Either way, the effect of suppressing deformation during molding is ensured.

In one embodiment, the maximum height of the second rib is configured to be equal to or less than the maximum height of the first rib.

In addition, in one embodiment, the components are made of polycarbonate resin. Since polycarbonate resin is a resin material that has a large amount of deformation due to cooling, the configuration of the present disclosure is highly effective.

In one embodiment, the extended end of the non-design portion is configured to extend further toward the rear surface than the rear end of the design portion.

In one embodiment, the extension distance of the non-design portion is 100 mm or more. If the extension distance is long, the deformation during molding is also large, and the configuration of the present disclosure is therefore highly effective.

As is clear from the above explanation, we provide an injection molded product with ribs that can suppress deformation during molding while ensuring reinforcing function.

1 is a front view of a vehicle lamp equipped with an injection-molded product (reflector unit) according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view of the vehicular lamp taken along line II-II in FIG. 1 . FIG. 2 is a front perspective view of the reflector unit. FIG. 2 is a rear perspective view of the reflector unit. 1 is a graph of test data showing the relationship between the vertical wall rib and the amount of deformation during molding. This is a modified example.

Specific embodiments of the present invention will be described below with reference to the drawings. The embodiments are illustrative and do not limit the invention, and all of the features and combinations thereof described in the embodiments are not necessarily essential to the invention.

(Vehicle lighting fixtures)
Fig. 1 is a front view of a vehicle lamp 1 including a reflector unit 40 which is an injection molded product according to a preferred embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1.

As shown in Figures 1 and 2, the vehicle lamp 1 comprises a lamp body 2 and a lamp cover 4 as a housing. The lamp body 2 has an opening at the front. The lamp cover 4 is made of a translucent resin, glass, or the like, and is attached to the opening of the lamp body 2 to define a lamp chamber S inside.

In the defined lamp chamber S, a low beam unit LU and a high beam unit HU are arranged vertically side by side when viewed from the front. The high beam unit HU is fixed to the low beam unit LU by a fixing member (not shown) with its position and orientation adjusted in the left-right direction.

(High beam unit)
First, there will be described the high beam unit HU disposed at the lower part within the lamp chamber S. The high beam unit HU is a lamp unit that forms a high beam light distribution, and includes a first light source 10 which is a light-emitting element, and a high beam reflector 20.

The high beam reflector 20 is a stepped reflector divided into multiple reflective elements, and is curved from the bottom toward the front and upward. The first light source 10 is attached to the flat bottom surface 21 provided below, with the light-emitting surface facing vertically upward.

The first light source 10 is a white LED (Light Emitting Diode), but is not limited to this, and may be a semiconductor light emitting element such as an LD (Laser Diode) or an EL (Electro Luminescence) element, a light bulb, an incandescent lamp (halogen lamp), a discharge lamp, etc.

The high beam reflector 20 has a reflective surface 22 on its inner surface that reflects light, and is configured to reflect the light emitted from the first light source 10 and project a high beam light distribution pattern toward the front of the vehicle.

The high beam reflector 20 is formed with an extension section 23 that extends upward from the front end. The high beam reflector 20 is positioned below and in front of the low beam unit, and the entire high beam unit HU, including the extension section 23, conceals non-optical parts (non-design parts) such as the support section of the low beam unit LU from the outside.

(Low beam unit)
Next, a description will be given of the low beam unit LU disposed at an upper portion within the lamp chamber S. The low beam unit LU is a lamp unit that forms a low beam light distribution, and includes a second light source 30 that is a light-emitting element, and a reflector unit 40.

The reflector unit 40 has a reflector portion 60 that functions as a reflector for low beams, and an upper bracket portion 50 and a lower bracket portion 70 that function as support members (brackets) for supporting the reflector unit 40. In other words, the reflector unit 40 has the functions of both a reflector and a bracket.

The reflector unit 40 is mainly composed of, from the top, an upper bracket part 50, a reflector part 60, and a lower bracket part 70, all of which are integrally molded as an injection molded product. By providing a single multifunctional part, the number of parts can be reduced, and manufacturing and assembly costs can be kept down.

The reflector section 60 is a stepped reflector divided into multiple reflective elements, and is curved generally downward and forward. The second light source 30 is attached to the flat eaves section 61 provided above, with the light-emitting surface facing vertically downward. In this way, the reflector section 60 is symmetrical in the up-down direction to the high beam reflector 20.

The second light source 30 is a white LED, the same as the first light source 10. The reflector unit 60 has an inner surface that is a reflective surface 62 that reflects light, and is configured to reflect the light emitted from the second light source 30 and project a low-beam light distribution pattern toward the front of the vehicle.

The extension reflector 90 is a concealing material that conceals unnecessary parts. Non-optical parts (non-design parts) such as the mechanical parts and fixed parts of the low beam unit LU and high beam unit HU are concealed from the outside by the extension reflector 90.

(Reflector unit 40)
The reflector unit 40 will now be described in detail. Fig. 3 is a front perspective view of the reflector unit 40. Fig. 4 is a rear perspective view of the reflector unit 40.

As mentioned above, the upper bracket portion 50 and the lower bracket portion 70 are support members for supporting the reflector unit 40 itself.

The upper bracket portion 50 is a thin plate whose thickness direction is the front-to-rear direction, and is formed at the center of the rear side of the eaves portion 61, protruding upward. A through hole 51 is formed at the center of the upper bracket portion 50, penetrating it in the front-to-rear direction.

The lower bracket portion 70 is provided adjacent to the lower side of the reflector portion 60, and has an extension surface 71 that continues from the lower end of the reflector portion 60 and folds back onto the rear surface. The extension surface 71 is made up of a first extension portion 71a that extends onto the rear surface a predetermined distance across the entire width in the left-right direction, and a second extension portion 71b that continues from the first extension portion 71a and extends further onto the rear surface with a narrower predetermined width. The second extension portion 71b is provided in two places, on the left and right, and the lower bracket portion 70 has a shape that is symmetrical in the left-right direction.

The extension end of each second extension portion 71b is provided with an engagement surface 72 that extends continuously vertically downward. The engagement surface 72 has approximately the same shape as the upper bracket portion 50, is a plate shape with its thickness direction in the front-to-rear direction, and has a through hole 73 formed in the center. The engagement surface 72 and the upper bracket portion 50 are provided in parallel.

The through hole 51 of the upper bracket part 50 and the through hole 73 of the lower bracket part 70 are formed for mounting the mount M. The mount M is mounted in the upper through hole 51 and the two through holes 73 on the left and right of the lower part, respectively, and the aiming screw E screwed into the mounted mount M is attached to the lamp body 2 (see Figure 2).

The low beam unit LU is supported by three aiming screws E, and by rotating the aiming screws E, the optical axis of the low beam unit LU is adjusted horizontally and vertically. The optical axis of the high beam unit HU is adjusted relative to the low beam unit LU when it is attached to the low beam unit LU, and the high beam unit HU is directly supported by the low beam unit LU and tilts together with it as a single unit.

The left and right side surfaces 74 of the engagement surface 72 are connected to the side edges of the second extension portion 71b. They are also connected to a vertical surface 75 that extends downward from the extension end of the first extension portion 71a, forming a box-like configuration in which each component surface is continuous and integrated. For this reason, the lower bracket portion 70 is shaped to be resistant to static and dynamic loads as a retaining member.

(rib)
Returning to Figure 2, the lower bracket portion 70 is adjacent to the reflector portion 60 in the vertical direction and is configured to be continuous with the lower part of the reflector portion 60, which has a recessed shape on the rear side, and folded back to the rear side. As a result, a narrow space SP is formed on the rear side of the reflector unit 40 between the reflector portion 60 and the lower bracket portion 70 (more specifically, the extension surface 71).

A rib 80 is provided in the narrow space SP to firmly connect the reflector part 60 and the lower bracket part 70 and improve the rigidity of the reflector unit 40.

As shown in FIG. 4, the ribs 80 extend in the vertical direction, have a thin plate shape with the thickness direction being the left-right direction, and are provided in multiple numbers spaced apart in the left-right direction. The ribs 80 include a first rib 81 and a second rib 82.

The first rib 81 is provided on the first extension portion 71a and crosses in the vertical direction, connecting the first extension portion 71a and the front end of the reflector portion 60, thereby connecting the reflector portion 60 and the extension surface 71.

The second rib 82 is provided on the second extension portion 71b, is integrally formed with the first rib 81, and is provided in the form of a vertical wall that protrudes upward from the second extension portion 71b.

The first rib 81, which is connected in the vertical direction, mainly serves to increase the rigidity of the reflector unit 40. By connecting the reflector part 60 and the lower bracket part 70 across in the vertical direction, the strength is increased and deformation due to static loads or dynamic loads while the vehicle is moving is suppressed.

The second rib 82 mainly serves to suppress deformation during molding. The second rib 82 is provided along the long extending second extension portion 71b up to its extension end, so that the contact area with the mold increases, and the rib sticks to the mold when cooling after injection molding, reducing the amount of deformation due to thermal contraction.

If the only goal is to improve rigidity, the larger the rib, the greater the rigidity. However, as the volume of the rib increases, the amount of heat generated during molding and the amount of deformation during molding also increase, making it easier for silver streaks to occur, which can lead to molding defects. In particular, when the extension distance from the fold is long, ribs are essential to ensure rigidity, but because the volume of injection molded products is large, the amount of heat generated during injection molding is large and molding defects are likely to occur. Previously, only ribs connecting the top and bottom were provided, which led to large deformation during molding and caused molding defects.

In this embodiment, the first rib 81 is provided to improve the rigidity of the reflector unit 40, and the second rib 82 is provided to reduce the amount of deformation caused by thermal contraction during injection molding. This ensures a good balance between reinforcing performance and suppression of deformation during injection molding.

(Test Data)
A rib formed in a vertical wall shape, such as the second rib 82, has the effect of suppressing thermal deformation even if it is not connected vertically.

Figure 5 is a graph of test data, showing the relationship between the length (molding distance) of the upright rib when it is provided on the extension surface that is folded back and extended from the lower end of the reflector section, and the amount of deformation due to thermal contraction during injection molding. The upright rib is formed at a specified height from the folded back section. The horizontal axis shows the length of the upright rib, with the molding distance of the upright rib increasing as it moves to the right. The vertical axis shows the amount of deformation during injection molding, with the amount of deformation increasing as it moves upward. For comparison, the values for the conventional product are shown with a dotted line.

As shown in FIG. 5, even standing ribs protruding from the extending surface, i.e., ribs that are not connected to the reflector portion, have the effect of suppressing deformation during molding, and the longer the standing rib is provided, the smaller the amount of thermal deformation during molding becomes, and the greater the effect of suppressing deformation becomes. When the standing rib is provided up to the extending end, the amount of deformation during molding becomes the smallest, so in this embodiment, the second rib 82 is provided up to the extending end to suppress the amount of deformation during molding.

In addition, the vertical wall-shaped rib has the effect of suppressing deformation during molding even if its height (protruding height) is low. In order to suppress the amount of heat during molding and suppress molding defects, it is preferable that the height is equal to or less than a predetermined value. Specifically, it is preferable that the maximum height of the second rib 82 is greater than 0 mm and equal to or less than 5 mm, and it is even more preferable that the maximum height is equal to or less than 3 mm.

The same applies to the first rib 81. It is preferable that the maximum height of the first rib 81 is 3 mm or less, since this helps to suppress molding heat in the narrow space SP.

In this embodiment, the first rib 81 is provided vertically across the first extension portion 71a from the tip to the rear end, but this is not limited thereto. The first rib 81 may be provided partway up the first extension portion 71a, and the second rib 82 may be formed continuously from the partway up the first extension portion 71a. Also, although all the first ribs 81 have the same shape, the first rib 81 connected to the second rib 82 may be shorter, lower, and smaller than the other first ribs 81 in order to reduce the amount of heat during molding.

The first rib 81 and the second rib 82 may be connected in a curved or stepped manner, or an intermediate rib that gradually decreases in height may be provided between the first rib 81 and the second rib 82.

At the extension surface 71, which is the folded portion, the extension end of the extension surface 71 extends further toward the rear side than the rear end of the reflector section 60, and the extension distance is 100 mm or more. Because of its large volume, the amount of heat generated during injection molding is large, and the shape is prone to deformation during molding, but the second rib 82 keeps deformation during molding below the allowable amount, and also prevents the adverse effect of deformation on the light distribution of the reflector section 60. When the extension distance is long, the effect of the configuration disclosed herein is large and is preferable.

When a part that is integrally molded with a non-design part that is not visible from the outside, such as the lower bracket part 70, is a design part that constitutes a specific function or design, such as an optical component that forms the light distribution, such as the reflector part 60, or a design surface with an intricate emblem, the required molding dimensions are also strict, and are suitable for the configuration of this disclosure.

It is more preferable that the constituent members of the reflector unit 40 are made of a resin material that has a large amount of deformation due to cooling, such as polycarbonate resin, since this configuration has a large effect.

(Modification)
The configuration of the present disclosure is not limited to the above. Modifications will be described with reference to Fig. 6. Components having equivalent configurations are given the same reference numerals and descriptions thereof will be omitted.

As shown in FIG. 6(A), the reflector unit 140 has a second rib 182 on the rib 180. The second rib 182 has a generally triangular shape with a height that decreases toward the extended end. Even if the upright rib has a generally triangular shape, it can suppress molding deformation, improve the release characteristics from the mold, and reduce the overall weight and heat during molding more than a rectangular shape, just like the rectangular second rib 82. For this reason, the upright rib may be configured so that its height decreases toward the end. The decrease in height toward the end includes not only a linear decrease, but also a curved decrease and a step-like decrease.

As shown in FIG. 6B, the reflector unit 240 has a first rib 281 on the rib 280. The first rib 281 has a rectangular cutout 281a formed at its side end. The first rib 281 is connected to the lower bracket part 70 and the reflector part 60 in the vertical direction, and the second rib 82 is formed continuously from one end of the cutout lower part. The cutout 281a reduces the amount of heat during molding of the narrow space SP, suppresses the amount of deformation during molding, and improves the release characteristics from the mold. In this way, the first rib may have a shape with a cutout. The cutout shape is not limited to a rectangular shape, and may be a curved shape such as a triangular shape or a semicircular shape.

The above describes preferred embodiments of the present invention, but the above embodiments are merely examples of the present invention, and these can be combined based on the knowledge of those skilled in the art, and such combinations are also included in the scope of the present invention.

1: Vehicle lamp 40: Reflector unit 60: Reflector portion 70: Lower bracket portion 71: Extension surface 80: Rib 81: First rib 82: Second rib SP: Narrow space

Claims (8)

The device is provided with a design portion having a predetermined shape recessed on the back surface and constituting a required appearance or function, and a non-design portion that is folded back continuously from the periphery of the design portion and is adjacent to the design portion across a narrow space,
A rib is provided in the narrow space,
The rib includes a first rib that connects the design portion and the non-design portion in a crosswise direction;
a second rib formed integrally with the first rib and extending to an end of the non-design portion in a vertical wall shape on the non-design portion,
An injection molded article characterized by: The second rib is formed to a height not exceeding 3 mm.
2. The injection molded product according to claim 1 . The second rib is formed to have a substantially constant height up to the extending end of the non-design portion.
3. The injection molded product according to claim 1 or 2. The second rib is formed to decrease in height toward the extending end of the non-design portion.
3. The injection molded product according to claim 1 or 2. The maximum height of the second rib is equal to or less than the maximum height of the first rib.
The injection molded product according to any one of claims 1 to 4. The component is made of polycarbonate resin.
The injection molded product according to any one of claims 1 to 5. The extended end portion of the non-design portion is formed to extend further toward the rear surface than the rear surface side end portion of the design portion.
The injection molded product according to any one of claims 1 to 6. The extension distance of the non-design portion is 100 mm or more.
The injection molded product according to any one of claims 1 to 7.