JP7604106B2 - Extension member - Google Patents

Description

This invention relates to an extension member made of PBT resin.

In vehicle lamps, the extension members that conceal the internal structure are becoming more complex in shape due to design needs. For example, Patent Document 1 discloses a vehicle lamp equipped with multiple optical units, and such a combination lamp uses a large extension member with multiple openings through which the light emitted by each optical unit passes.

In recent years, extension components have increasingly been made of PBT (polybrylene terephthalate) resin, which is highly heat-resistant, highly abrasion-resistant, and inexpensive.

JP 2014-165130 A

However, because PBT resin has high vacuum adhesion, it tends to stick to the mold. An opening is formed in the extension member to allow the light emitted from the optical unit to pass through, but if there are multiple openings with different opening areas, when molding with PBT resin, the openings with larger opening areas tend to stick to the cavity side mold, and the openings with smaller opening areas tend to stick to the core side mold. This causes an imbalance of stress on the molded product when the mold is opened, and the stress concentrates on the smallest cross-sectional area points, such as the piers, in the smallest openings, causing breakage.

The present invention was made in consideration of this, and provides an extension member made of PBT resin that suppresses the occurrence of breakage during molding.

In order to achieve the above object, in one aspect of the configuration of the present disclosure, a vehicle lamp having a plurality of optical units that emit light is provided with an extension member that shields at least a portion of the optical units from the outside, the extension member being an injection molded product made of PBT resin,
The extension member is configured to have one or more pier sections that divide the opening through which the light emitted from the optical unit passes into multiple sections with different opening areas, and the minimum cross-sectional area section of the pier section has a parting line mark formed on its side surface, in the front-to-back surface direction, closer to the front surface.

PBT resin has a high degree of vacuum adhesion and therefore tends to stick to the mold. In extension members with two or more openings with different opening areas, the larger openings stick to the mold on the cavity side and the smaller openings stick to the mold on the core side, resulting in an unbalanced stress on the molded product when the mold is opened. The piers are formed thin to separate the openings, so when the mold is opened, the smallest cross-sectional area of the pier is subjected to a large amount of stress and breaks. In response to this, the mold boundary of the smallest cross-sectional area is moved closer to the core side, the core side molding surface is increased compared to the cavity side molding surface, and the configuration is such that it comes into contact with the core side more, allowing the pier to firmly stick to the core side mold and preventing breakage of the smallest cross-sectional area when the mold is opened. The mold boundary remains on the molded product as a parting line mark.

In one embodiment, the cross-sectional area of the minimum cross-sectional portion is set to be 0.2 ^cm2 or more and less than 0.4 ^cm2 . Conventionally, the minimum cross-sectional area was required to be 0.4 ^cm2 or more to prevent breakage. By configuring as described above, the minimum cross-sectional area can be made smaller, which increases the freedom of design and also allows for weight reduction.

In one embodiment, the back side of the pier portion, including the minimum cross-sectional area portion, is configured to have a pressing mark. Because the core-side molding surface is increased, the minimum cross-sectional area portion, which tends to stick to the core-side mold, tends to remain in the core-side mold during ejection. For this reason, a protrusion is provided on the core-side mold of the minimum cross-sectional area to prevent breakage during the ejection process. The mark created by the protrusion remains as a pressing mark on the bottom surface of the minimum cross-sectional area of the molded product.

In one embodiment, the pressure mark on the minimum cross-sectional area portion is formed only in approximately half of the thickness direction of the pier portion. If a fillet is provided at the bottom corner of the minimum cross-sectional area portion, a very small protrusion corresponding to the fillet will be formed on the protruding member. To avoid this, the protruding member is configured so that only half of the thickness direction extends over the minimum cross-sectional area. This prevents breakage during protrusion, and allows the molded product to be removed from the mold reliably.

As is clear from the above explanation, the present invention provides an extension member made of PBT resin that suppresses the occurrence of breakage during molding.

1 is a front view showing a schematic structure of a vehicle lamp including an extension member according to an embodiment; 2(B) is a cross-sectional view taken along line II(B)-II(B) of FIG. 2(A) showing an extension member. 1A and 1B are perspective views of an extension member, in which FIG. 1A is a perspective view from the front side, and FIG. FIG. This is a cross-sectional view of the mold for the pier section taken along line II(B)-II(B) in FIG. 2. 1A and 1B are schematic diagrams showing the arrangement of protruding members relative to the extension member, in which (A) shows the arrangement of the protruding members of this embodiment and (B) shows the arrangement of a conventional protruding member for comparison. This is an example of 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.

(Embodiment)
1 is a front view of a vehicle lamp 1 including an extension member 10 according to an embodiment of the present invention. The vehicle lamp 1 is a right headlamp and is mounted on the front right side of a vehicle.

As shown in FIG. 1, the vehicle lamp 1 comprises a lamp body 2 and a front cover 3. The lamp body 2 is formed in a box shape with an opening. The front cover 3 is made of a translucent resin, glass, or the like, and is attached to the opening of the lamp body 2 to form a lamp chamber. Three optical units LU1 to LU3 and an extension member 10 are arranged in the lamp chamber.

Optical units LU1 to LU3 are equipped with light sources that are light-emitting elements, and emit light emitted from the light sources forward of the vehicle. In this embodiment, optical unit LU1 is a variable light distribution unit that forms a light distribution pattern adapted to the driving conditions of the vehicle and the surrounding conditions, and irradiates the light forward of the vehicle. Optical units LU2 and LU3 are turn signal lamp units and positioning lamp units, respectively, and emit amber light and white light, respectively, forward of the vehicle. Hereinafter, except when a specific optical unit is specified, the three optical units LU1 to LU3 will be collectively referred to as optical unit LU.

The optical unit LU may be of any known type, such as a scanning mechanism device, a reflector type device, or a projector type device. The configuration of the present disclosure is not limited to an extension member used in the headlamp of the above-mentioned combination lamp. It may be widely applied as an extension member that conceals the internal configuration in various vehicle lighting fixtures in which a combination lamp using multiple optical units is arranged, such as tail lamps, turn signal lamps, stop lamps, clearance lamps, daytime running lamps, cornering lamps, hazard lamps, positioning lamps, back lamps, and fog lamps.

(Extension member)
2 and 3 show the extension member 10, with Fig. 2(A) being a front view, Fig. 2(B) being a cross-sectional view taken along line II(B)-II(B) in Fig. 2(A), Fig. 3(A) being a front perspective view (oblique view from the front side), and Fig. 3(B) being a rear perspective view (oblique view from the rear side). In Fig. 2 and Fig. 3, the extension member 10 is colored with light ink to clearly show the opening.

The extension member 10 is disposed in front of the optical unit LU and covers the gap between the optical unit LU and the lamp body 2, as well as the gap between adjacent optical units LU, to prevent the internal structure of the optical unit LU from being seen from the outside. It is a thin-walled injection-molded product made of PBT (polybrylene terephthalate) resin.

The extension member 10 is composed of a frame portion 11 that forms the peripheral wall, a first pier portion 20 that is attached to the inside of the frame portion 11 and extends horizontally, and a second pier portion 30 that is attached to the frame portion 11 and the first pier portion 20 and extends vertically.

The two piers 20, 30 on the frame 11 form openings OP1 to OP3 for passing the light emitted from the optical unit LU at positions corresponding to the optical units LU1 to LU3, respectively.

First, the first pier 20 that extends horizontally from the frame 11 divides the opening inside the frame 11 into two large openings in the vertical direction: opening OP1 and openings OP2 and OP3. The first pier 20 is located higher up than the center in the vertical direction, and the opening OP1 formed at the bottom is wider than the openings OP2 and OP3 formed at the top. The optical unit LU1 uses a large optical device as the device to emit high-intensity light at a wide angle to form a light distribution and ensure the driver's visibility in the dark, and the corresponding opening OP1 also has a very large opening area.

The second pier 30 spans the upper opening divided by the first pier 20, and is located to the right of the center in the left-right direction. Therefore, the opening OP2 formed on the left is wider than the opening OP3 formed on the right. The second pier 30 further divides the opening inside the frame 11 divided by the first pier 20.

With the above configuration, the opening areas of the openings OP1 to OP3 are all different, and the opening area of the opening OP1 is larger than the combined opening area of the openings OP2 and OP3.

As shown in Fig. 2(B), the cross-sectional shape of the first pier 20 and the frame 11 is an inverted U-shape. Therefore, as shown in Fig. 3(B), a peripheral wall 14 is formed extending vertically from the outer periphery of the opening OP1. In addition, a peripheral wall 15 extending vertically is formed on the outer periphery shared by the openings OP2 and OP3.

The cross-sectional shape of the second pier portion 30 is an inverted J-shape, and the second pier portion 30 separating the relatively small openings OP2 and OP3 is formed shorter in the vertical direction than the first pier portion 20, has a narrower width, and is thin-walled, making it the minimum cross-sectional area portion having a smaller cross-sectional area than any other portion of the extension member 10.

(Mold for bridge pier)
Here, the second pier 30 and its molding method will be described. FIG. 4 is an enlarged perspective view of the second pier 30, and is a downward perspective view to show the characteristics of the back side of the second pier 30. In FIG. 4, the dimensions of the depth of the pressing mark and the protruding length of the parting line mark do not reflect the actual dimensions, but show the configurations typically. FIG. 5 is a schematic diagram showing the schematic configuration of the pier mold 40 of the second pier 30, and is a cross-sectional view at a position corresponding to the line II(B)-II(B) in FIG. 2(A). The pier mold 40 constitutes a part of the mold of the extension member 10.

Before describing the features of the second pier 30, we will first explain the molding die and molding method shown in Figure 5.

As shown in FIG. 5, the pier mold 40 is composed of a cavity side mold 41 and a core side mold 42 having an ejection member 43.

The protruding member 43 is held in a hole 42b provided in the core side mold 42 so that it can slide up and down. The protruding member 43 is provided so that it engages only half of the bottom surface of the second pier portion 30 to be molded in the thickness direction.

The opposing surfaces of the cavity side mold 41 and the core side mold 42 including the ejection member 43 are formed with a cavity side molding surface 41a and a core side molding surface 42a, respectively. When the cavity side mold 41 and the core side mold 42 are arranged facing each other and clamped, the two molding surfaces 41a, 42a define a molding space S1 inside that corresponds to the shape of the second pier portion 30.

The boundary 44 between the cavity side mold 41 and the core side mold 42 is configured to be flush with the surface of the second pier 30 to be molded. For this reason, the cavity side molding surface 41a is substantially flat and configured to mold only the surface 31 of the second pier 30. On the other hand, the core side molding surface 42a is formed by digging down from the surface of the core side mold 42 by the height of the second pier 30 in order to form the surface other than the surface 31 of the second pier 30.

As described above, by configuring the pier mold 40 so that the boundary 44 between the cavity side mold 41 and the core side mold 42 is flush with the surface 31 of the second pier 30, the area of the core side molding surface 42a is made much larger than the area of the cavity side molding surface 41a. Therefore, the molded product molded with the pier mold 40 adheres closely to the core side mold 42.

(Action and Effect)
Among the openings OP1 to OP3 provided in the extension member 10, the opening OP1 has a larger opening area than the openings OP2 and OP3. The opening OP3 has a smaller opening area than the opening OP2. In addition, the PBT resin constituting the extension member 10 is generally and widely used in injection molding because it has high heat resistance, excellent abrasion resistance, and is inexpensive, and has a higher degree of vacuum adhesion than, for example, polypropylene resin, polyester resin, etc.

Conventionally, in injection molded products made of polyester resin, the parting line (boundary) is located at the bottom of the molded product. The front side of the molded product is formed by the cavity side mold, and the back side is formed by the core side mold with an extrusion member. If there is an opening, the peripheral wall surface of the opening is formed by the molding surface on the cavity side. When molding with PBT resin using a mold configured so that the parting line is the bottom surface, the opening of the molded product adheres closely to the cavity side mold with the molding surface because the vacuum adhesion of PBT resin is high. When a molded product has multiple openings with different opening areas, the opening with a large opening area is likely to stick to the cavity side mold because the surface area in contact with the cavity side mold is large. However, since the surface area in contact with the cavity side mold of the opening with a small opening area is relatively small, it is likely to remain on the core side mold when the mold is opened, and the balance of stress applied to the molded product when the mold is opened is poor. For this reason, when the mold is opened, stress is concentrated on the smallest cross-sectional area of the molded product, and the molded product easily breaks at the smallest cross-sectional area.

In the extension member 10 of this embodiment, the opening area of the opening OP1 is large, and the inner surface (opening side) of the peripheral wall 14 adheres closely to the cavity side mold. Since the opening areas of the openings OP2 and OP3 are small in comparison, the inner side of the peripheral wall 15 adheres closely to the cavity side mold, but the area in contact with the cavity side mold is smaller than that of the peripheral wall 14, and the peripheral wall 15 tends to remain in the core side mold when the mold is opened. In the mold opening process of the extension member 10, the frame part 11, which has the largest volume and surface area, tends to remain in the core side mold, so that the entire part remains in the core side mold. However, when the peripheral wall 14 is pulled by the cavity mold, the periphery of the openings OP2 and OP3 is also pulled by the cavity side mold, and the most stress is applied to the second pier part 30, which is the smallest cross-sectional area part.

In this embodiment, the pier mold 40 is configured so that the boundary portion 44 is flush with the surface 31 of the molded product, so that the core side molding surface 42a is much larger than the cavity side molding surface 41a. Because the area in contact with the core side mold 42 is large, the second pier 30 adheres firmly to the core side mold 42. This adhesion force can counter the pulling force applied to the cavity side mold on the second pier 30, which is the smallest cross-sectional area, when the mold is opened, and the molded product including the second pier 30 remains in the core side mold. This suppresses the occurrence of breakage at the smallest cross-sectional area when the mold is opened for molded products with different openings. As with the pier mold 40, the effect of suppressing breakage in the molded product can be achieved by simply increasing the core side molding surface only to the smallest cross-sectional area where the most stress is applied.

(Arrangement of protruding members)
After the mold is opened, the molded product attached to the core side mold is ejected upward by the ejection member 43 and removed as an ejection process. Here, the arrangement of the ejection members of the entire extension member 10 will be described with reference to FIG. 6. FIG. 6 shows a schematic arrangement of the ejection members relative to the rear view (rear view) of the extension member. FIG. 6(A) shows the arrangement of the ejection members relative to the extension member 10 in this embodiment, and FIG. 6(B) shows the arrangement of the conventional ejection members. The extension member 110 in FIG. 6(B), shown for comparison, has the same shape as the extension member 10 and has a pier portion 130. In order to clearly show each opening, the extension members 10 and 110 are colored with light ink, and the ejection members P and 43 are hatched.

As shown in FIG. 6(A), in this embodiment, the extension member 10 is provided with four protruding members P on each of the four sides, three protruding members P at the opening OP1, and a protruding member 43 that extends over the second pier portion 30.

In contrast, in the conventional embodiment, as shown in FIG. 6(B), the arrangement of the ejection member P is the same, but the ejection member 43 is not provided. This is because, in the conventional embodiment, the molded product is released from the core side mold by being ejected by the other ejection members, even if an ejection member is not provided in the opening with a small opening area.

However, as mentioned above, PBT resin tends to stick to the mold. The pier 130 in FIG. 6(B) is the smallest cross-sectional area, so stress tends to concentrate on it during ejection. This can cause breakage as it tries to remain in the core-side mold during the ejection process. Furthermore, in this embodiment, to prevent the molded product from breaking during the mold opening process, the pier mold 40 for the second pier 30 is configured so that the boundary 44 is flush with the surface 31 of the molded product. This allows the second pier 30 to adhere firmly to the core-side mold 42 in the small opening area.

For this reason, as shown in Figures 5 and 6 (A), a protruding member 43 is provided to reliably push out the second pier section 30, which is the section with the smallest cross-sectional area and where stress is likely to concentrate, and to remove the extension member 10.

(Second pier)
The second pier 30 formed by the pier mold 40 having the above-mentioned configuration will now be described in detail with reference to FIG.

As shown in FIG. 4, parting line marks 34 are formed along the longitudinal direction at the corners of the surface 31 of the second pier. The parting line marks 34 are formed as burrs at the boundary 44 between the cavity side mold 41 and the core side mold 42 that mold the second pier 30, protruding laterally. The parting line marks are formed in a line shape during injection molding, and when the protruding portion is polished in a later process, they remain on the pier as polishing marks. Such parting line marks are also included in the scope of the present invention.

In addition, a pressing mark 35 is formed on a part of the bottom surface of the second pier 30. The pressing mark 35 is formed as a small rectangular depression on the bottom surface of one leg of the second pier 30, approximately at the center in the longitudinal direction, and approximately on only the outer half in the thickness direction.

The impression is left in the part where the ejection member provided on the mold pushes up the molded product that is stuck to the mold during ejection in order to remove the molded product from the mold during injection molding. In this embodiment, the impression is formed on the molded product by the ejection member 43 provided on the pier mold 40 ejecting the molded product remaining in the core side mold 42. Since the impression is formed by protruding at least a part of the protruding surface into the molded product, not only does the shape of the protruding surface, such as a circle or rectangle, remain as it is as the impression, but sometimes only a part of the protruding surface, such as a semicircle, remains, and such impression is also included in the scope of the present invention.

The protruding member 43 is arranged so that it only engages half of the bottom surface of the second pier 30 in the thickness direction to be molded. To prevent non-rounded corners from injuring the hands, the corners of the molded product, including the bottom corners, are provided with a fillet with an extremely small radius of curvature (not shown in this embodiment). When the protruding member is configured to fit the bottom surface of the molded product, it is necessary to form a very small protrusion to form this small fillet. In order to avoid the formation of a very small protrusion, it is configured so that it only engages half of the thickness direction in this way. It is not limited to this, and it is also possible to provide a nest and configure the protruding member so that it engages entirely in the thickness direction.

Conventionally, in order to prevent breakage during molding, the minimum cross-sectional area was required to be 0.4 cm2 or ^more . Extension members have become more complex, and design and weight reduction needs have led to a demand for a smaller minimum cross-sectional area. With the above configuration, breakage at the minimum cross-sectional area of the molded product during injection molding is suppressed, so the minimum cross-sectional area can be made smaller than before. Specifically, even if the cross-sectional area of the second pier portion 30, which is the minimum cross-sectional area of the extension member 10, is 0.2 ^cm2 or more and less than 0.4 ^cm2 , it can be molded without breakage. The configuration of the present disclosure allows for a more flexible design of the extension member.

The cross-sectional shape of the minimum cross-sectional area portion may be either an inverted U-shape or an inverted J-shape , so long as the cross-sectional area is equal to or greater than 0.2 ^cm2 and less than 0.4 ^cm2 .

(Modification)
Fig. 7 shows modified examples, and Fig. 7(A) shows the second pier 30' as a modified example. Fig. 7(B) shows a pier mold 40' which is a mold for forming the second pier 30'. The same reference numerals are used to designate components having the same configuration as the above embodiment, and the description thereof is omitted. Note that the protruding member 43 is omitted.

As shown in FIG. 7B, parting line marks 34 are formed on the side surface 36 of the pier portion 30' in the vertical direction (surface-to-back surface direction), slightly closer to the surface 31 than the center.

As shown in FIG. 7B, the pier mold 40' is configured so that the boundary 44 is not flush with the surface of the second pier 30', but is located approximately in the center of the side surface 36. Since PBT resin is relatively soft, the mold does not have a draft angle to make it easier to remove the molded product.

In the above embodiment, the pier mold 40 is configured so that the boundary 44 is flush with the surface 31 of the second pier 30, but at least the effect of suppressing breakage during molding can be obtained by simply moving the boundary, which was conventionally configured to be flush with the bottom surface of the molded product, closer to the surface. By increasing the area of the core side mold molding surface and decreasing the area of the cavity side molding surface, the force of adhesion to the core side mold can be increased, and the resistance can be increased. As shown in Figure 7 (B), it is preferable to configure the mold so that the boundary 44 is formed slightly closer to the surface than the center in the surface-rear surface direction of the molded product, as this provides a high degree of suppression of breakage.

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 10: Extension member 20: First pier portion 30: Second pier portion 31: Surface 34: Parting line mark 35: Press mark LU: Optical units OP1 to OP3: Opening

Claims (4)

An extension member is provided in a vehicle lamp having a plurality of optical units that emit light, the extension member is disposed in front of the optical units, has a plurality of openings formed therein for passing light emitted from the plurality of optical units, and covers gaps between the optical units to conceal an internal structure of the optical units from being seen from the outside,
It is an injection molded product made of PBT resin.
A frame-shaped frame portion with a large opening on the inside ,
At least one pier portion that is attached to the inside of the frame portion and is formed thinner than the frame portion,
A plurality of openings having different opening areas are formed inside the frame by the pier portion ,
the frame portion has a parting line mark formed on a bottom surface portion, which is a back surface that is a non-design portion of the injection molded product, in a front-back direction;
At least one of the piers has a parting line formed near the surface, which is a design portion of the injection molded product, in the front-back direction;
The cross-sectional shape of the pier having the parting line mark formed near the surface is an inverted U-shape or an inverted J-shape.
An extension member characterized by: At least one of the piers has a cross-sectional area of 0.2 ^cm2 or more and less than 0.4 ^cm2 ;
2. The extension member according to claim 1 . At least one of the piers has a pressing mark formed on the back side thereof.
2. The extension member according to claim 1 . The pressure mark of at least one of the piers is formed only in half of the thickness direction of the pier.
4. The extension member according to claim 3.