JP3745940B2 - Resin molded body and molding die thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded body having a punching portion in which a large number of holes are intensively provided, such as a speaker grill, and a molding die thereof, and more particularly to a resin molded body having an improved appearance of the punching portion and a molding die thereof About.
[0002]
[Prior art]
FIG. 7 is a front view showing a door trim 1 for an automobile mounted on a door panel. The door trim 1 for an automobile has a door trim upper 1a and a door trim lower 1b for the purpose of comparing the appearance and simplifying a molding die. The door trim upper 1a and the door trim lower 1b are molded into a desired curved surface shape by molding press molding a general-purpose synthetic resin such as PP (polypropylene) resin. After inserting the ultrasonic boss provided on one side into the mounting hole on the other side, the end of the ultrasonic boss is crimped to join the door trim upper 1a and the door trim lower 1b along both the joining lines. Is doing.
[0003]
The door trim lower 1b is molded into a required shape by a mold press molding method having excellent moldability. However, the speaker grill 2 formed integrally with the lower part on the front side is not attached with a separate object, but is molded into the door trim lower 1b. At the same time, it is integrally formed as a punching part.
[0004]
The conventional method for integrally forming the speaker grill 2 on the door trim lower 1b will be described with reference to FIG. 8. The molding die 3 includes a cavity die 4 capable of moving up and down by a predetermined stroke, a core die 5 on the fixed side, It is composed of an injection molding machine 6 connected to the core mold 5, and immediately before the cavity mold 4 and the core mold 5 are clamped, the molten resin enters the product cavity from the injection molding machine 6 through the manifold 5a and the gate 5b. M is distributed and supplied onto the mold surface of the core mold 5, and then the cavity mold 4 is lowered to the bottom dead center and a predetermined press pressure is applied, so that the door trim lower 1 b is molded into a desired curved shape. .
[0005]
Punching blocks 7 and 8 are provided in the cavity mold 4 and the core mold 5, respectively, as a mold structure for integrally molding the speaker grill 2 when molding the door trim lower 1b.
[0006]
The mold surface of the cavity mold 4 which is the product surface of the door trim lower 1b is provided with a drawing pattern for transfer onto the product surface. Similarly, the mold surface of the punching block 7 attached to the cavity mold 4 is used. As for, the drawing pattern is engraved.
[0007]
Therefore, when the mold press molding is completed, the door trim lower 1b is molded into a required shape, the speaker grill 2 is integrally molded, and the surface of the general part of the door trim lower 1b and the surface of the speaker grill 2 are beautifully squeezed. A pattern is formed.
[0008]
[Problems to be solved by the invention]
As described above, in the door trim lower 1b integrally formed with the speaker grill 2, the diaphragm pattern engraved on the mold surface of the punching block 7 is transferred to the surface of the speaker grill 2. As shown in FIG. The opening corner portion of the punching hole 9 is rounded, and the punching hole 9 is set in an under shape that slightly inclines inward as the molded product is removed. The diaphragm pattern 2a formed on the surface has a configuration in which the diaphragm pattern 2a is cut off at the R-processed under part. However, the burr a is likely to occur at the diaphragm part and the appearance of the speaker grill 2 is deteriorated. Has been pointed out.
[0009]
Therefore, as the final product, there is a problem that an operation for removing the burr a is required, which increases the cost and causes an increase in the cost of the product.
[0010]
The present invention has been made in order to solve such problems. In a resin molded body in which a punching portion is integrally formed by intensively drilling a large number of punching holes, a drawn pattern in the punching portion is provided. An object of the present invention is to provide a resin molded body and a molding die thereof which can finish the parting of the sheet.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a resin molded body having a punching portion in which a large number of holes are intensively drilled, and a plurality of stepped punching holes are formed in the punching portion. The drawn pattern provided on the surface of the part is formed up to the surface of the step part in the stepped punching hole.
[0012]
Furthermore, the molding die according to the present invention is a molding die of a resin molded body having a punching portion in which a large number of holes are intensively drilled, and includes a movable cavity mold, a fixed core mold, The cavity mold corresponding to the punching part, and a punching block provided in the core mold. The cavity side punching block has a large number of stepped punching holes intensively. A stepped projection for forming is formed, and the drawn pattern formed on the mold surface of the punching block is extended to the stepped portion of the stepped projection.
[0013]
As is clear from the above configuration, the drawn pattern formed on the punching portion surface is configured to be cut off at the end of the stepped portion in the stepped punching hole, so that the drawn pattern at the punched portion can be easily cut off. .
[0014]
In addition, burr is likely to occur at the parting line if it is configured so that the stop pattern can be cut off at the R stop as in the past, but if a configuration where the stop is cut off at the stepped end is used, the occurrence of burr can be reliably prevented. , No deburring work is required.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a resin molded body and a molding die thereof according to the present invention will be described in detail with reference to the accompanying drawings.
[0016]
FIG. 1 is a front view showing an automobile door trim according to the present invention, FIGS. 2 and 3 are sectional views showing the structure of the automobile door trim, and FIG. 4 is an overall view showing a molding die according to the present invention. FIG. 6 is an explanatory view showing a process of forming a punching portion using the molding die according to the present invention.
[0017]
A specific example in which the present invention is applied to an automobile door trim will be described with reference to FIGS. 1 to 3. The automobile door trim 10 includes a door trim upper 20 and a door trim lower 30. A flange 21 is formed along the front end side of the waist portion, and a door inner seal 22 is supported and fixed to the waist flange 21, and the door trim upper 20 is formed by press-molding PP resin mixed with talc. By molding, it is formed into a desired curved surface shape.
[0018]
Similarly, the door trim lower 30 is molded into a desired curved shape by molding press molding of PP resin mixed with talc, and a door pocket opening 31 is formed in a substantially central portion. 32 (a punching portion in the present invention) is integrally formed. In addition, as a joining structure of the door trim upper 20 and the door trim lower 30, a mounting boss 33 formed so as to protrude from the back side along the upper edge of the door trim lower 30 is provided corresponding to the door trim upper 20. After being inserted into the door trim, the door trim upper 20 and the door trim lower 30 are firmly joined and fixed by applying an ultrasonic caulking process, a thermal caulking process, or a push nut stop to the tip of the mounting boss 33.
[0019]
By the way, the door trim 10 for automobiles according to the present invention has a diaphragm pattern 30a formed on the surface of the general part and a diaphragm pattern 32a formed on the speaker grill 32. The structure of the speaker grille 32 can be easily cut off at the punching holes 34 of the drawn pattern 32a formed on the surface of the speaker grille 32, and the burr removal operation can be omitted, thereby improving the productivity of the speaker grille 32. In addition, it is a problem to provide a molding die thereof.
[0020]
As shown in FIG. 3, in order to constitute the speaker grille 32, a number of stepped punching holes 34 are formed, and the ends of the stepped portions 35 on the surface side of the stepped punching holes 34 are drawn patterns 32a. The feature is that it was closed.
[0021]
Therefore, by eliminating the conventional R portion, burrs are not generated, and it becomes easy to close the drawn pattern 32a.
[0022]
The molding die used for molding the door trim lower 30 in the door trim 10 and the molding process will be described in detail with reference to FIGS. First, the overall configuration of the molding die 40 will be described with reference to FIG. 4. The molding die 40 includes a cavity die 50 that can move up and down by a predetermined stroke, a core die 60 on the fixed side, and an injection molding connected to the core die 60. The machine 70 is generally configured.
[0023]
More specifically, the cavity mold 50 can be moved up and down by a predetermined stroke by an elevating cylinder 51, and a drawn pattern 52 is engraved along the mold surface of the cavity portion 50a of the cavity mold 50.
[0024]
On the other hand, the core mold 60 is provided with a manifold 61 and a gate 62 that serve as a resin passage for the molten resin from the injection molding machine 70, and distributes the molten resin to predetermined locations on the mold surface of the core mold 60 through the manifold 61 and the gate 62. Resin supply means for supplying is provided.
[0025]
The door trim lower 30 is formed into a desired curved shape by clamping the cavity mold 50 and the core mold 60. In order to integrally form the speaker grill 32 at this molding, as shown in FIG. Punching blocks 53 and 63 are embedded in 50 and the core mold 60, respectively. Further, the mold surface of the cavity-side punching block 53 has a large number of irregularities, and the convex surface 54 comes into contact with the mold surface of the core-side punching block 63 so that the molten resin M spreads in the concave portion 55. 55 are in communication with each other. Further, a diaphragm pattern 56 is engraved on the bottom surface of the recess 55 so that the diaphragm pattern 32 a can be transferred to the product surface of the speaker grill 32.
[0026]
Furthermore, in order to form the stepped punching hole 34 of the speaker grille 32 as the uneven structure of the punching block 53 embedded and fixed in the cavity mold 50, a large number of stepped protrusions 57 protrude toward the product cavity. The drawn pattern 56 formed on the mold surface of the punching block 53 is cut off at the base portion (step portion) 57 a of the stepped protrusion 57.
[0027]
Accordingly, the mold state of the door trim lower 30 during mold press molding is such that the molten resin M is supplied from the injection molding machine 70 through the manifold 61 and the gate 62 into the product cavity, and the cavity mold 50 and the core mold 60 are clamped to obtain a desired shape. The door trim lower 30 is formed.
[0028]
As shown in FIG. 6, a plurality of stepped punching holes 34 are formed in the door trim lower 30 by the stepped protrusions 57 provided in the punching block 53 embedded and fixed in the cavity mold 50, and The drawing pattern 52 provided on the mold surface and the drawing pattern 56 provided on the mold surface of the punching block 53 are transferred to the surface of the door trim lower 30. In particular, the drawing pattern 56 formed on the punching block 53 is stepped. Since it is cut off at the end of the base 57 a of the protrusion 57, the drawn pattern 32 a of the speaker grill 32 to be molded is cut off at the step 35 of the stepped punching hole 34.
[0029]
In the embodiment described above, the punching block 53 is embedded and fixed at a predetermined position of the cavity mold 50, and the door trim lower 30 is formed by clamping the cavity mold 50 and the core mold 60. The stepped punching hole 34 is integrally formed, and the drawn pattern 32 a is cut off at the end of the stepped portion 35 of the stepped punching hole 34.
[0030]
On the other hand, when forming the speaker grille 32 by providing a concavo-convex portion on the mold surface of the punching block 63 of the core mold 60 and making the structure movable up and down, the core punching block 63 is pushed up before mold press molding. Then, the projecting surfaces of the cavity side punching block 53 and the core side punching block 63 are brought into contact with each other to form a stepped punching hole 34. After molding, the core side punching block 63 is drawn into the core mold 60, thereby forming. The present invention can also be applied to a molding die having a structure that promotes demolding of the product.
[0031]
Further, instead of the upper and lower divided structure of the door trim upper 20 and the door trim lower 30, a punching portion such as the speaker grill 32 described above can be formed on a door trim in which the door trim 10 is formed as a single body.
[0032]
【The invention's effect】
As described above, according to the resin molded body and its molding die according to the present invention, a plurality of stepped punching holes are formed to form the punching portion, and at the same time, a drawn pattern terminal formed on the surface of the punching portion. By cutting out at the stepped end of the stepped punching hole, the drawing pattern in the punching part can be cut off beautifully and easily, and the generation of burrs can be prevented, thus eliminating the need for burrs removal and production. It has the effect of improving the properties.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment in which the present invention is applied to an automobile door trim.
2 is a cross-sectional view taken along line II-II in FIG.
3 is a cross-sectional view showing a configuration of a punching portion in the automobile door trim shown in FIG. 1. FIG.
FIG. 4 is an explanatory view showing an overall configuration of a molding die for a resin molded body according to the present invention.
5 is an explanatory view showing a state before molding in the molding die shown in FIG. 4; FIG.
FIG. 6 is an explanatory view showing a state when the punching block is abutted in the molding die according to the present invention.
FIG. 7 is a front view showing a conventional automobile door trim.
FIG. 8 is an overall view showing a molding process of a conventional automobile door trim.
FIG. 9 is an explanatory view showing a punching portion in a conventional resin molded body.
[Explanation of symbols]
10 Automotive Door Trim 20 Door Trim Upper 30 Door Trim Lower 32 Speaker Grill (Punching Part)
34 Stepped punching hole 35 Stepped portion 40 Molding die 50 Cavity die 51 Lifting cylinder 52 Drawing pattern 53 Punching block (cavity side)
56 Drawing pattern 57 Stepped protrusion 57a Step portion 60 Core type 61 Manifold 62 Gate 63 Punching block (core side)
70 Injection molding machine

Claims (2)

A resin molded body (30) having a punching portion (32) in which a large number of holes are punctured and drilled, and a plurality of stepped punching holes (34) are formed in the punching portion (32). The drawn pattern (32a) provided on the surface of the portion (32) is formed up to the step (35) end in the stepped punching hole (34). A molding die (40) of a resin molded body (30) having a punching portion (32) in which a large number of holes are punctured, and includes a movable cavity mold (50) and a fixed core mold (60), an injection molding machine (70) connected to the core mold (60), and a punching block (53, 53) provided in the cavity mold (50) and the core mold (60) corresponding to the punching portion (32). 63), and the cavity side punching block (53) is formed with stepped protrusions (57) for intensively forming a number of stepped punching holes (34), and the punching block (53) A molding die for a resin molded body, wherein the drawn pattern (56) formed on the mold surface is extended to the step portion (57a) of the stepped protrusion (57).

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