JPH0785903B2 - Mudguard molding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for molding a mudguard sandwich-molded with a core layer and a skin layer, and more particularly to the location of a small flow path for a tab in a molding die thereof.

[Prior art]

For example, as shown in FIGS. 7 to 10, a mudguard 9 attached to the rear of a vehicle wheel includes a main body 930 that comes into contact with an outer plate of a vehicle body, a lower piece 940 provided below the main body 930, and a main body 930.
It is composed of a rear piece 943 protruding in an inverted L shape from the substantially central portion. The rear piece 943 has a rear mounting hole 91, the side portion has a side mounting hole 92, and the upper portion has an upper mounting hole 93.
A substantially u-shaped recess is provided between the main body 930 and the rear piece 943.
Have 945. Reference numeral 95 is a gate portion at the time of injection molding.

In addition, the mudguard 9 is formed by sandwich molding.
As shown in FIG. 8, it comprises a core layer 7 and a skin layer 6 covering the surface of the core layer 7. That is, the main body 93
Around the 0, the rear mounting hole 91, the side mounting hole 92, and the upper mounting hole 93, a hard core layer 7 is provided inside to provide rigidity, and the outer periphery is covered with a soft skin layer 6. is doing. Further, since the lower piece 940 comes into contact with a division block or the like of a parking lot, it is configured only by the skin layer 6 to give flexibility.

Further, in manufacturing the sandwich molding mudguard 9, as shown in FIG. 9, a molding die 8 having a cavity 80 having the outer shape of the mudguard is used. The mold 8 includes a gate 82, a rear core 83 for forming a rear mounting hole 91 and a draining core 84 for forming a drainage hole 90, and an excess of the skin layer material 60 and the core layer material 70. It has a tab 87 and a small flow path 86 for flowing out. Further, the small flow path 86 is provided on the center line L of the rear core 83.
The description of the rear piece 943, the side mounting hole 92, the cavity of the upper mounting hole 93, and the core is omitted.

When sandwich-molding the mudguard 9, the skin layer material 60 for forming the skin layer 6 is first injected into the cavity 80, and then the skin layer material 60 is formed.
A core layer material 70 for forming the core layer 7 is injected into the inside. Then, the surplus skin layer material 60 and the core layer material 70 are replaced with the small flow path 86.
Through tab 87.

In this way, the mudguard 9 shown in FIGS. 7 and 8 is obtained. Immediately after the molding, the mudguard 9 is provided near the rear mounting hole 91 near the tab 87 and the small passage 86.
It has a small flow path product 861 and a tab product 871 formed by. Therefore, this small flow path product is cut and removed at the root portion with the rear piece 943. Further, a small flow path product 861 and a tab product 871 are also formed in the vicinity of the side mounting hole 92, and are similarly removed. As a result, the mudguard 9 shown in FIGS. 7 and 8 is obtained. Further, a small flow path product 861 and a tab product 871 are also formed in the vicinity of the side mounting hole 92, and are similarly removed.

[Problems to be solved]

The conventional mudguard 9 has the following problems.

That is, the mudguard 9 formed by the conventional molding method is
As shown in FIG. 10, the periphery of the rear mounting hole 91 in the upper part is surrounded by the skin layer 6, and the core layer 7 is almost absent. Therefore, the periphery of the rear mounting hole 91 is flexible and has insufficient rigidity for fastening by bolts.

The cause is that, as shown by the arrow F in FIG. 9, the core layer material 70 for forming the core layer 7 has a rear mounting hole 91.
It only flows to one side around the rear core 83 for forming.

Therefore, it is necessary to adopt a method of forming the core layer 7 also around the rear mounting hole 91.

By the way, for the purpose of only forming the core layer 7 around the rear mounting hole 91, the skin layer material 60 and the core layer material 60 are formed.
The position of the gate 82 for injecting 70 may be changed to the position 89 directly below the rear core 83.

However, if the position of the gate 82 is set in this way, the core layer material 70 does not flow sufficiently behind the draining core 84 in the mudguard 9, and the desired sandwich-shaped mudguard cannot be obtained.

Therefore, the inventors have made various studies and have completed the present invention.

In view of such conventional problems, the present invention aims to provide a method for forming a mudguard, which can manufacture a mudguard in which a core layer is sufficiently formed around the upper mounting hole.

[Means for solving problems]

The present invention comprises a substantially L-shaped main body, a lower piece provided at a lower portion of the main body, and a rear piece disposed on the lower piece so as to face the main body, and the rear piece is attached to the rear piece. There is a hole, and a drain hole is provided in the lower part of the main body facing the lower piece,
When sandwich-molding a mudguard composed of a core layer and a skin layer, a draining core for forming the draining hole and a rear core for forming the rear mounting hole are formed in a cavity having a shape of a molded product. A molding die is provided which is provided with a tab near the rear core through a small passage. Then, the small flow path is orthogonal to the front end surface of the molded product positioned in the mainstream direction of the core layer material, and on the draining core side within an angle range of 10 to 90 degrees with respect to the perpendicular passing through the center of the rear core. It is provided unevenly. Then, the skin layer material is injected from the gate into the cavity, and then the core layer material is injected into the skin layer material, and the core layer material fills the inside of the cavity and around the rear core. Then, the core layer material is injected until it reaches the inside of the tub through the small flow path.

What is most noticeable in the present invention is that when the mudguard is sandwich-molded, the small passages for the tabs are provided unevenly on the draining core side within an angle range of 10 to 90 degrees with respect to the perpendicular line. It is to use a mold.

With respect to the small flow path forming position, the front end surface of the molded product located in the mainstream direction of the core layer material is the front end surface (reference numeral 308 in FIG. 2) in the vicinity of the tab. The small channels are provided on the draining core side in an angle range of 10 to 90 degrees with respect to a perpendicular line which is orthogonal to the tip end surface of the molded product and passes through the center of the side core. Outside this angular range, the core layer material does not flow around the rear core and the core layer cannot be formed around the rear mounting hole.

The small channel preferably has a channel height of 0.3 to 1 mm. If it is less than 0.3 mm, it is difficult for the surface layer material and the core layer material to flow into the tab, and if it exceeds 1 mm, the skin layer material flows in from the beginning and the core layer material does not flow in. Moreover, it is preferable that the length of the small channel is 2 to 10 mm. Further, the width of the small flow path is preferably 10 to 20% of the width of the draining core.

In addition, the tab has a volume into which the core layer material can flow after the skin layer material.

Examples of the material for the skin layer include polypropylene blended with EPDM, EVA resin, SEBS resin, SBS resin, and soft PVC resin.

Also, as the core layer material, there are ABS resin, hard PVC resin, polypropylene resin containing a filler such as talc. In addition, some of these are mixed with glass fiber.

When injecting the core layer material into the skin layer material,
The skin layer material can also be injected together around the core layer material.

[Action and effect]

In the present invention, the sandwich molding of the mudguard is performed using the molding die in which the small passage for the tab is arranged within the above angle range.

Then, in molding, first, the skin layer material is injected into the cavity. Then, the core layer material is injected into the skin layer material. After the inside of the cavity is filled with both of them, the skin layer material small channel first enters, then the core layer material enters the small channel, and both of them form a sandwich shape and enter the tab. After that, the mold is cooled. By this,
A mudguard molded product is obtained.

In the mudguard thus obtained, the core layer is formed in the skin layer around the rear mounting hole (fourth layer).
See figure).

The reason why the core layer is formed around the rear mounting hole as described above is not clear, but by setting the small channel at the above position, the flow of the skin layer material and the core layer in the cavity can be improved. It is thought that this is due to a change from the conventional flow.

As described above, according to the present invention, it is possible to provide a mudguard molding method capable of manufacturing a mudguard in which the core layer is sufficiently formed around the rear mounting hole.

〔Example〕

First Embodiment A mudguard forming method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. The outer shape of the mudguard to be obtained in this example is the same as that of the conventional example.

The molding die 3 used in this molding method is shown in FIGS.
As shown in the figure, a cavity 30 having the shape of a mudguard 9 as a molded product has a rear core 33 for forming a rear mounting hole and a drain core 34 for forming a drain hole. Then, a tab 37 is provided in the vicinity of the rear core 33 via a small flow path 36. Further, the gate 32 is provided on the upstream side of the draining core 34, as in the above-mentioned conventional technique.

Further, the small flow path 36 is, as shown in FIGS. 1 and 2,
A position P that is orthogonal to the front end surface 308 of the molded product for forming the front end surface 137 (FIG. 5) of the rear piece 143 of the mudguard and is at an angle α with respect to the perpendicular M passing through the center O of the rear core 33.
It is provided in. In this example, the angle α is about 40 degrees.

Next, in the sandwich molding of the mudguard, as shown in FIG. 3, the skin layer material 60 is injected from the gate 32 into the cavity 30, and then the core layer material 70 is injected into the skin layer material 60. . The core layer material 70 reaches the periphery of the rear core 33 through the periphery of the draining core 34 while filling the inside of the gavity 3 as shown by the arrow in FIG. The core layer material 70 is an extra skin layer material from the small channel 36.
While pushing 60 onto the tab 37, slightly fill the tab 37 with liquid.
As a result, the inside of the cavity is filled with the skin layer material 60 and the core layer material 70.

After that, the skin layer material 60 and the core layer material 7 in the cavity 30
Cool and solidify 0 and take out the mudguard molded product.

As shown in FIG. 4, the mudguard 1 thus obtained has the same outer shape as that of the conventional mudguard 9 except that the positions of the small flow path product 18 and the tab product 19 are different.

That is, the mudguard 1 has a main body 13 as shown in FIG.
0, a lower piece 140, a rear piece 143, and a U-shaped upper inner side portion 141, and a rear mounting hole formed by the rear core 33.
11 and a drain hole 10 formed by the drain core 34. The tip surface 137 has a small passage 36, a small passage product 18 formed by the tab 37, and a tab product 19. Further, the small flow path product 18 and the tab product 19 are cut and removed from the tip surface 137. Also, in the vicinity of the side hole 12, similar small flow path products 171,
The tab product 172 is formed, but these are also cut and removed. Further, in the figure, reference numeral 15 is a gate portion and 145 is a concave portion.

As shown in FIG. 4, the inner structure of the mudguard 1 near the rear mounting hole 11 has a sufficient core layer 7 formed around the rear mounting hole 11, and the rear mounting hole 11 has high rigidity. There is.

Also, as shown in FIG. 5, the rear mounting hole 11, the side mounting hole 1
The core layer 7 is sufficiently formed around the 2 and the upper mounting hole 13. Further, the small flow channel product and the tab product also include an inner core layer 7 and an outer skin layer 6. The other internal structure is the same as that of the conventional example.

As shown in FIGS. 3 and 4, a thin skin layer 6 is formed on the inner wall surfaces of the rear mounting hole 11, the side mounting hole 12, and the upper mounting hole 13.

As described above, according to this example, the rear mounting hole 11, the side mounting hole 12, and the upper mounting hole 13 are all surrounded by the core layer 7, and the mudguard 1 having high rigidity can be obtained.

Second Embodiment In this embodiment, in the first embodiment, the rear piece 143 is provided with a mounting piece projecting rearward, and the rear mounting hole 11 is formed in the mounting piece.

Therefore, in this example, as shown in FIG. 6, in the molding die 4, at a position projecting from the end surface 408 of the molded product,
The cavity 40 provided with the protruding tip portion 431 for forming the above-mentioned mounting piece is used. Then, a small flow path 411 is provided in the vicinity of the rear core 43 provided in the protruding tip portion 431.

That is, in this example, a perpendicular line M which is orthogonal to the front end surface 408 of the molded product of the cavity 40 and which passes through the center O of the rear core 43,
A small flow path 411 is provided between a line T orthogonal to the perpendicular M. The small flow path 411 has an angle β of 30 degrees with respect to the perpendicular M and is provided at a position unevenly distributed on the draining core 44 side. The small channel 411 is communicated with the tab 42. Others are the same as those in the first embodiment.

In this example, the core layer material 70 injected into the skin layer material 60 flows as shown by the arrow in FIG.
It flows into the tab 42 via 1.

Further, according to this example, similarly to the first example, it is possible to obtain a mud ghat in which the core layer 7 is formed around the side mounting holes.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 5 show a first embodiment, FIG. 1 is a plan view of a molding die, FIG. 2 is an arrangement view of small channels and tabs, and FIG. Explanatory drawing showing the flow of the core layer material in the cavity, FIG. 4 is a cross-sectional view around the rear mounting hole, FIG. 5 is a perspective view of the mudguard, and FIG. 6 is the arrangement of the small channels and tabs in the second embodiment. Drawings, Figs. 7 to 10 show a conventional example, Fig. 7 is a perspective view of a mudguard, Fig. 8 is a sectional view taken along the line YY of Fig. 7,
FIG. 9 is an explanatory diagram showing the flow of the core layer material in the cavity, and FIG. 10 is a sectional view around the rear mounting hole. 1 …… Mudguard, 11 …… Rear mounting hole, 12 …… Side mounting hole, 13 …… Upper mounting hole, 18 …… Small channel product, 19 …… Tab product, 3,4 …… Molding die, 30 , 40 …… cavity, 308,408 …… Molded product tip surface, 33,43 …… Rear core, 34,44 …… Draining core, 36,411 …… Small channel, 37,42 …… Tab, 6 …… Skin Layer, 60 …… Skin layer material, 7 …… Core layer, 70 …… Core layer material,

Claims (1)

[Claims] 1. An L-shaped main body, a lower piece provided at a lower portion of the main body, and a rear piece disposed above the lower piece so as to face the main body. The rear piece has a rear portion. There is a mounting hole, a drainage hole is provided in the lower part of the main body facing the lower piece, and when a mudguard composed of a core layer and a skin layer is sandwich-molded, the inside of the cavity having the shape of the molded product is formed. A mold having a draining core for forming the drainage hole and a rear core for forming the rear mounting hole, and a tab provided near the rear core through a small channel. And the small flow path is perpendicular to the front end surface of the molded product located in the mainstream direction of the core layer material and an angle of 10 ° is formed with respect to a perpendicular line passing through the center of the rear core.
It is provided unevenly on the draining core side in the range of up to 90 degrees, and the skin layer material is injected into the cavity, and then the core layer material is injected into the skin layer material. A method for molding a mudguard, characterized in that the core layer material is injected while filling the inside, reaching the periphery of the rear core, and further flowing out into the tub through the small flow path.