JP3979564B2 - Mold for molding molded resin - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold for molding a resin molded body having an undercut portion, and in particular, there is no problem such as deformation of the terminal portion and whitening, and the resin molded body can be smoothly demolded. The present invention relates to a molding die.
[0002]
[Prior art]
FIG. 8 and FIG. 9 show a door trim 1 installed in a door panel on the driver's seat side of a passenger car. An undercut inner seal flange 2 is formed along the upper edge at the waist of the automobile door trim 1. The inner seal flange 2 is slidably sealed with an elevating door window glass and a door inner seal (not shown) is attached.
[0003]
Further, a corner cover 3 is formed on the front waist portion of the door trim 1 so as to face upward, and this corner cover 3 has an ornament function for preventing the door mirror mounting portion from being exposed to the indoor side.
[0004]
And since the door trim 1 is a mass-production part and a large-sized part, the stamping mold method is frequently used. At this time, when the wood trimming groove portion 1a is formed in the door trim 1, the slide core for forming the inner seal flange 2 to be undercut cannot be set in space, and as shown in FIG. A mold structure with a raised core is used.
[0005]
That is, the molding die 4 includes upper and lower molding molds 4a and 4b that can be mutually opened and clamped, and an ejector mechanism 5 of the door trim 1 that is a resin molded body.
[0006]
In the conventional ejector mechanism 5, the ejector pin 7 is connected to the vertically moving ejector plate 6, and the door trim 1 is pushed up. The undercut inner seal flange 2 and the corner cover 3 are formed on the door trim 1. Therefore, a straight-up core 8 is attached to the tip of the ejector pin 7 in order to mold the inner seal flange 2.
[0007]
Then, after molding the door trim 1 by clamping the molding upper and lower molds 4a and 4b, the ejector pin 7 rises simultaneously with the mold opening of the molding upper mold 4a, and the door trim 1 is removed from the molding lower mold 4b. The
[0008]
[Problems to be solved by the invention]
In this way, when the automotive door trim 1 is formed by using the stamping mold method, particularly when the inner seal flange 2 having an undercut shape is formed by the straight-up core 8, when the door trim 1 is removed, the direction a in FIG. When the door trim 1 is pivoted and the undercut inner seal flange 2 is lifted from the core 8, the ejector pins 7a protruding the corner cover 3 interfere with the corner cover 3, and the corner Problems such as deformation of the cover 3 or surface defects such as whitening at the base of the corner cover 3 have been pointed out.
[0009]
If the ejector pin 7a is not set on the corner cover 3 in order to simply avoid interference, there is a problem (deformation) due to a demolding failure with the lower mold 4b.
[0010]
In addition, it is conceivable to set the straight-up core 8 to a two-stage stroke to avoid the interference between the ejector pin 7a and the corner cover 3. However, in such a case, there is a problem that the structure becomes complicated and the mold cost increases. .
[0011]
The present invention has been made in view of such circumstances. For example, the present invention is a molding die suitable for molding a door trim having a corner cover for a door mirror, and causes problems such as deformation and whitening of the corner cover. In addition, an object of the present invention is to provide a molding die for a resin molded body that can realize a smooth demolding operation.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a molding die for a resin molded body having an undercut portion, and a molding upper and lower mold capable of mutual clamping and mold opening, and a molding upper and lower mold. It is composed of an ejector mechanism that pushes up the resin molded body when opened, and the ejector mechanism is lifted by the vertical drive of the ejector plate and pushes up the portion including the undercut portion of the resin molded body, and the spring force of the spring The ejector pin is a two-system drive type ejector pin that rises due to the undercut part and pushes up the part located on the product terminal side from the undercut part . The ejector of the spring drive type with respect to the lift stroke amount of the ejector pin of the ejector plate drive type by increasing the stroke of the pin is smaller, the resin molded body Kicking during demolding of the undercut portion, characterized in that to avoid interference between the ejector pin terminal portion and the spring drive method of a resin molded body.
[0013]
Here, the molding die can be applied to a mold press molding die or an injection molding die. For example, in a mold press mold, the upper mold can be moved up and down by a predetermined stroke by the operation of the lifting cylinder, and when the upper mold is lowered to the bottom dead center, The supplied molten resin spreads in the product cavity, and a resin molded body having a desired shape can be molded. The lower mold for molding supplies molten resin supplied from an injection molding machine to a predetermined portion of the lower mold for molding through a manifold and a gate.
[0014]
On the other hand, in the injection mold, the molten resin is injected and filled into the product cavity after the upper and lower molds are clamped.
[0015]
Further, the ejector mechanism built in the lower mold for molding is provided with two types of ejector pins: an ejector pin driving type ejector pin and a spring driving type ejector pin.
[0016]
As an ejector pin of the ejector plate driving system, a plurality of ejector pins are connected to the ejector plate in order to push the resin molded body upward, and among these, a straight-up core is attached to the tip of the ejector pin corresponding to the undercut portion. ing.
[0017]
Moreover, the spring drive type ejector pin is set at a portion located outside the straight-up core, such as a corner cover in a door trim, for example.
[0018]
As is apparent from the above configuration, the molding die according to the present invention is provided with two ejector pins as the ejector mechanism, and the portion outside the straight-up core driven by the ejector plate is a spring drive type ejector. A pin is set, and the upward stroke of the spring-driven ejector pin is smaller than that of the ejector plate-driven ejector pin (including the straight-up core), and the stroke amount is adjusted.
[0019]
Therefore, after molding, as the upper mold for molding rises, the ejector plate rises, and the resin molded body is pushed upward by the ejector pins and the straight-up core. At this time, the ejector pin located outside the straight-up core also rises due to the spring force of the spring, but the lift stroke of the ejector pin due to the spring force of the spring is small, so when the push-up is completed, resin molding There is a space between the body and the spring-driven ejector pin, and the resin-molded body and the spring-driven ejector pin interfere when the resin-molded body is rotated and removed from the straight-up core. Therefore, the resin molded body can be smoothly demolded without deformation or whitening of the terminal portion of the resin molded body.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a molding die for a resin molded body according to the present invention will be described according to a specific example applied to molding a door trim 1 for an automobile integrally provided with a corner cover 3 for a door mirror shown in the conventional example.
[0021]
FIG. 1 is an overall configuration diagram of an embodiment of a molding die according to the present invention, FIG. 2 is a configuration explanatory diagram showing a main part of an ejector mechanism in the molding die, and FIG. 3 is an operation explanatory diagram of the ejector mechanism. FIGS. 4 to 7 are explanatory views showing a door trim molding process and a demolding process. FIG. 4 is a molten resin supply process, FIG. 5 is a mold press molding process, and FIG. 7 is an explanatory view showing the state when the push-up is completed.
[0022]
In FIG. 1, a molding die 10 according to the present invention includes a molding upper and lower mold (forming upper mold 20 and molding lower mold 30) and a molding lower mold 30 that can be clamped and opened. It is generally composed of an ejector mechanism 40 that is built in.
[0023]
More specifically, the molding upper mold 20 can be moved up and down by a predetermined stroke by the operation of the lifting cylinder 21. When the molding upper mold 20 reaches the bottom dead center, the molding upper mold 20 is in contact with the molding lower mold 30. The molten resin is cooled and solidified and press-molded into a required shape, and the door trim 1 is molded.
[0024]
On the other hand, the molding lower mold 30 is connected to an injection molding machine that is not shown, but the molten resin supplied from the injection molding machine is placed on the mold surface of the molding lower mold 30 through the manifold 31 and the gate 32. To be distributed.
[0025]
Next, the ejector mechanism 40 that pushes up the door trim 1 formed into a required shape by clamping the upper and lower molds 20 and 30 is characterized in that the present invention employs a two-system drive system.
[0026]
That is, a plurality of ejector pins 43 are attached to an ejector plate 42 that is moved up and down by a predetermined stroke by an ejector rod 41, and the ejector pins 43 that are connected to the ejector plate 42 are in a normal state (the ejector plate 42 is in a lower position). When the tip is located on the mold surface of the molding lower mold 30 and the ejector plate 42 is raised, the door trim 1 is pushed upward.
[0027]
In order to mold the undercut inner seal flange 2 formed on the door trim 1, a straight core 44 is attached to the tip of a part of the ejector pin 43 (indicated by 43a). The inner seal flange 2 is integrally formed by the raised core 44.
[0028]
As described above, the ejector plate 42 is driven by the vertical movement of the ejector plate 42. The ejector pin 43 that pushes up the body portion of the door trim 1 and the ejector pin 43a of the straight-up core 44 that pushes up the undercut inner seal flange 2 are driven. It is.
[0029]
On the other hand, the ejector pins 45 used for releasing the corner cover 3 protruding upward from the front edge of the door trim 1 from the mold surface of the lower mold 30 are not driven by the ejector plate 42. Instead, it moves upward by the spring force of the dedicated spring 46.
[0030]
Further, the ejector pin 45 of the spring 46 drive system is configured so that the spring force of the spring 46 is applied by the ejector plate 42 so that the tip 45a coincides with the mold surface of the molding lower mold 30 before and during molding of the door trim 1. It is pressed so as not to work. When the ejector plate 42 is raised, the ejector pin 45 is raised by the spring force of the spring 46 as shown in FIG.
[0031]
The operation of the two-system ejector mechanism 40 will be described with reference to FIG. 3. First, as shown in FIG. 3A, when the ejector plate 42 is in the lower position at the time of molding and before molding, Both the ejector pin 43 attached to 42 and the ejector pin 45 spring-biased upward by the spring 46 are positioned at the lower position.
[0032]
Next, after the molding, if the ejector rod 41 operates and the ejector plate 42 rises as the molding upper mold 20 moves up, the ejector pin 43 connected to the ejector plate 42 rises. However, as shown in (b), the ejector pin 45 that is spring-biased by the spring 46 also acts by the spring force of the spring 46, and the ejector pin 45 also rises.
[0033]
Then, the spring 46 drive type ejector pin 45 stops rising when the spring 46 is fully extended.
[0034]
Next, as shown in (c), when the ejector plate 42 is further raised with respect to the ejector pin 45 that has stopped extending due to the extension of the spring 46, and the ejector plate 42 comes to the uppermost position, the tip of the ejector pin 43 And the tip of the spring-driven ejector pin 45 has a stroke difference corresponding to the dimension indicated by symbol d in the figure. A feature is that the space resulting from the difference in stroke is effectively utilized during the mold removal operation of the door trim 1.
[0035]
That is, a procedure for molding and removing the door trim 1 using the molding die 10 will be described. First, as shown in FIG. 4, when the molding upper mold 20 starts to move down by the operation of the lifting cylinder 21 and the mold clearance between the molding upper and lower molds 20 and 30 reaches 10 to 30 mm, an injection (not shown) is performed. Molten resin M such as PP (polypropylene) resin mixed with talc is supplied onto the mold surface of the molding lower mold 30 through the manifold 31 and the gate 32 from the molding machine.
[0036]
After that, as shown in FIG. 5, the molding upper mold 20 is lowered to the bottom dead center, and the molten resin M is filled into the mold clearance (about 2 to 3 mm) between the molding upper and lower molds 20 and 30, and desired. The door trim 1 is formed into a curved shape.
[0037]
At this time, the undercut inner seal flange 2 is formed integrally with the door trim 1 by the straight-up core 44, and the substantially triangular corner cover 3 protruding upward from the front edge of the door trim 1 is also integrally formed. Is done.
[0038]
When the molding of the door trim 1 is completed, the molding upper mold 20 starts to rise due to the operation of the lifting cylinder 21, and the ejector rod 41 operates in the ejector mechanism 40 and the ejector plate 42 rises accordingly. As a result, the ejector pin 43 and the straight raising core 44 connected to the ejector pin 43a are raised, and the main body of the door trim 1 is pushed upward.
[0039]
Similarly, when the ejector plate 42 moves upward, the restraint of the spring 46 is released, the spring force of the spring 46 acts, and the ejector pin 45 corresponding to the corner cover 3 is lifted, and the corner cover 3 Is removed from the lower mold 30 by the ejector pins 45 (see FIG. 6). The ejector pin 45 that pushes up the corner cover 3 stops when the spring 46 is fully extended.
[0040]
Next, as shown in FIG. 7, even if the ejector pin 45 that pushes up the corner cover 3 stops, the ejector plate 42 continues to rise due to the operation of the ejector rod 41, so that the ejector pin 43 and the straight raising core 44 are raised. Since the ejector pin 43 a further rises, the door trim 1 protrudes upward by the ejector pin 43 and the straight raising core 44.
[0041]
Then, in a state where the raising of the ejector plate 42 is stopped and the pushing up is completed, a difference is set in the stroke amount between the ejector pin 43 of the ejector plate 42 driving method and the ejector pin 45 of the spring 46 driving method. As shown in the figure, a space S is set between the corner cover 3 and the tip 45a of the ejector pin 45, so that when the inner seal flange 2 of the door trim 1 is peeled off from the straight core 44, it is directed in the direction P1 in the figure. If the door trim 1 is rotated and then peeled off in the P2 direction, the door trim 1 can be removed easily. However, at this time, a space S for rotating the corner cover 3 in the P3 direction is secured. The door trim 1 can be smoothly removed from the mold.
[0042]
At this time, since the corner cover 3 does not interfere with the ejector pin 45, the corner cover 3 is not deformed and the surface of the corner cover 3 is not defective such as whitening, and the appearance design is not impaired. Smooth demolding operation can be expected.
[0043]
In the above-described embodiment, the molding die 10 according to the present invention is applied to mold press molding. However, when applied to injection molding, the molding upper mold 20 is a cavity mold (fixed side), molding. After clamping the cavity mold and the core mold using the lower mold 30 as the core mold (movable side), the molten resin M may be injected and filled into the product cavity from the sprue of the cavity mold. It is the same as the construction method.
[0044]
Therefore, it can be applied to an injection mold and the resin molded body is not limited to the door trim 1.
[0045]
【The invention's effect】
As described above, the molding die according to the present invention employs two ejector pins, that is, an eject plate drive type ejector pin and a spring drive type ejector pin as a push-up mechanism, and an ejector pin drive type ejector pin. By setting the spring-driven stroke amount to be smaller than the stroke amount, it is possible to avoid interference between the molded body and the ejector pin when the resin molded body having an undercut-shaped portion is rotated and peeled off. In addition, since there is no problem of interference with the ejector pin even if the resin molded body is rotated, there is an effect that a smooth demolding operation can be expected without impairing the appearance performance.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing an embodiment of a molding die according to the present invention.
2 is a cross-sectional view showing a main part of an ejector mechanism in the molding die shown in FIG. 1. FIG.
FIG. 3 is an explanatory view showing the operation of the ejector mechanism in the molding die according to the present invention.
FIG. 4 is an explanatory view showing a molten resin supply process using a molding die according to the present invention.
FIG. 5 is an explanatory view showing a mold press molding process using the molding die according to the present invention.
FIG. 6 is an explanatory view showing a state in the middle of pushing up using the molding die according to the present invention.
FIG. 7 is an explanatory view showing a state at the completion of pushing up of a molded body using the molding die according to the present invention.
FIG. 8 is a front view showing an automobile door trim provided with a corner cover.
9 is a cross-sectional view taken along line IX-IX in FIG.
FIG. 10 is a structural explanatory view showing a molding die for a conventional automobile door trim.
FIG. 11 is an explanatory view showing a defect at the time of demolding of a resin molded body using a conventional molding die.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Automotive door trim 2 Inner seal flange 3 Corner cover 10 Molding mold 20 Molding upper mold 21 Drive cylinder 30 Molding lower mold 31 Manifold 32 Gate 40 Ejector mechanism 41 Ejector rod 42 Ejector plate 43, 43a Ejector pin ( Ejector plate drive system)
44 Straight-up core 45 Ejector pin (spring drive system)
46 Spring

Claims (1)

A molding die (10) for a resin molded body (1) having an undercut portion (2), which is capable of mutual clamping and mold opening (20, 30), and molding upper and lower molds (20, 30) when the mold is opened, the ejector mechanism (40) pushes up the resin molded body (1), and the ejector mechanism (40) is lifted by the vertical drive of the ejector plate (42) . Ejector pin (43) that pushes up the portion including the undercut portion (2) of the resin molded body (1) and the portion that is raised by the spring force of the spring (46) and is located on the product terminal side from the undercut portion (2) consists ejector pin two systems drive system of the ejector pin (45) pushing up the (43, 45), rising strike the ejector plate (42) driving system of the ejector pin (43) By increasing stroke of the spring (46) ejector pin drive system (45) is set smaller than the over-click amount, upon demolding the undercut portion of the resin molded body (1) (2), the resin A mold for molding a resin molded body characterized by avoiding interference between a terminal portion of the molded body (1) and an ejector pin (45 ) driven by a spring (46) .

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