JP7313399B2 - Mold and molding method of molded product - Google Patents

Description

The present invention relates to a mold for molding a molded article having an undercut portion and a molding method for the molded article .

For example, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-100031, there is known a slide core advancing/retreating mechanism having an angular pin for sliding a slide core and a guide portion for guiding the angular pin. In this slide core advance/retreat mechanism, the guide portion has an inner member formed with a pin insertion hole through which the angular pin is passed, and an outer member formed with an inner insertion hole through which the inner member is inserted. The axial direction of the hole substantially coincides with the axial direction of the outer member.

Japanese Patent Application Laid-Open No. 2020-82450

Conventionally, the core is divided into a piece structure, and after molding, the piece is manually taken out by an operator and disassembled.

However, if the operator performs these operations each time molding is performed, it takes time before the next molding is performed. Moreover, if it takes a long time to reach the next step, the core will cool down, so the temperature of the core must be raised before the next step is started, and it takes time to raise the temperature.

Moreover, the core is often heated to 100° C. or more, and it is difficult for workers to touch it with bare hands.

Furthermore, in the case of a large-sized molding die, the core may weigh more than 10 kg, and the work of disassembling the core is hard work.

The volume of the divided core is not constant, and there is a difference in the easiness of cooling for each core component. Attempting to assemble core component parts with different temperatures may result in damage to the core due to thermal expansion or the like, resulting in improper assembly.

On the other hand, with the slide core structure as in Patent Document 1, although continuous molding is possible, there is a parting line in the mold opening direction.

The present invention has been made in view of such a point, and its object is to make it possible to easily disassemble the core and take out the molded product even if it has an undercut part, while suppressing the occurrence of parting lines.

In order to achieve the above object, the present invention provides a core retainer plate that retains the core fixing pin at the locked position and can be opened at the open position.

Specifically, in the first invention, a mold for molding a molded product having an undercut portion includes an upper mold, a lower mold, and a core facing the cavity between the upper mold and the lower mold and composed of a plurality of core component parts,
The above mold is
a core fixing pin for fixing each of the plurality of core components;
a core retainer plate that has a plurality of slits for inserting the core fixing pins, locks the core fixing pins at a locked position, and can be opened at an open position that is rotationally or horizontally moved from the locked position;
and a plate driving mechanism for rotating or horizontally moving the core retainer plate.

According to the above configuration, when the plate driving mechanism rotates or horizontally moves the core retainer plate to an open position where the core fixing pin can be released, the plurality of core components can be disassembled and the molded product can be taken out without disassembling the entire mold.

In the second invention, in the first invention,
The fixing pin insertion slit of the core retainer plate has a width narrower than the maximum diameter of the core fixing pin at the locked position and a width larger than the maximum diameter of the core fixing pin at the open position.

According to the above configuration, it is possible to release the core fixing pin at the open position and retain the core fixing pin at the lock position with a simple configuration.

In a third invention, in the second invention,
The plate drive mechanism has a rotary drive unit that rotates the core retainer plate,
The rotary drive unit has a drive plate that is connected to the core retainer plate by a shaft, and has a mechanism that rotates the core retainer plate by moving in the direction of the rotation axis.

According to the above configuration, the core retainer plate rotates when the mold is opened and closed. Thereby, the core fixing pin is moved to the open position to enable disassembly of the core components.

In a fourth invention, in any one of the first to third inventions,
The above core is
an upper core component having an outer diameter at its upper end greater than an outer diameter at its lower end;
a lower core component having a central through hole through which the lower side of the upper core component is inserted, the outer diameter of the upper end being larger than the outer diameter of the lower end;
A cavity between the upper core component and the lower core component forms an undercut of the molded product.

According to the above configuration, it is possible to take out the molded product after molding without disassembling the entire mold, even if the molded product has ribs that serve as undercut portions on the inner peripheral surface.

The molded article of the fifth invention is molded by the mold according to any one of the first to fourth inventions, having an undercut portion on at least one of the inner surface and the outer surface and no intersecting parting line on the surface.

According to the above configuration, it is possible to obtain a molded product that has an undercut portion and no intersecting parting lines and has a good appearance and high marketability. In the method of producing an undercut portion using a slide core, intersecting parting lines are generated, but in the present invention, two or more intersecting parting lines are not generated.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, even a molded product having an undercut portion can be easily disassembled and taken out while suppressing the occurrence of a parting line.

1 is a cross-sectional view showing a mold in a clamped state according to Embodiment 1 of the present invention; FIG. FIG. 2 is a cross-sectional view corresponding to FIG. 1 in a state where the force of the first push rod to push the core retainer plate is reduced; FIG. 2 is a cross-sectional view corresponding to FIG. 1 in a state in which the force with which the second push rod pushes the drive plate is reduced; FIG. 2 is a sectional view equivalent to FIG. 1 showing how a first biasing member pushes up a drive plate; FIG. 4 is a plan view showing the core retainer plate and its surroundings in a state where the first biasing member pushes up the drive plate; It is a perspective view which expands and shows a drive plate. FIG. 2 is a cross-sectional view corresponding to FIG. 1 showing how a core retainer plate is rotated by a driving plate; 4C is a plan view equivalent to FIG. 4B showing how the drive plate rotates the core retaining plate and the core fixing pin rotates. FIG. FIG. 2 is a cross-sectional view corresponding to FIG. 1 showing a state in which the upper mold is largely separated from the lower mold; FIG. 2 is a cross-sectional view equivalent to FIG. 1 showing how the core and the product are separated from the lower mold; FIG. 2 is a sectional view equivalent to FIG. 1 showing how the third core component is separated from the first core component, the second core component and the product; FIG. 2 is a sectional view equivalent to FIG. 1 showing how the second core component is separated from the first core component and the product; FIG. 7 is a cross-sectional view showing the mold in a clamped state according to Embodiment 2 of the present invention. FIG. 10 is a cross-sectional view showing a mold in a clamped state according to a modified example of Embodiment 2 of the present invention; 4(a) to 4(c) are cross-sectional views respectively showing modified examples of molds according to other embodiments.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a mold 1 according to Embodiment 1 of the present invention. This mold 1 is, for example, a mold for molding a molded product 5 having an undercut portion 5a, including a rectangular parallelepiped upper mold 2, a box-shaped lower mold 3, and a core 4 facing a cavity 50 between the upper mold 2 and the lower mold 3. Note that the number of core components may be two or four or more.

As shown in FIG. 4B, the mold 1 includes a total of six core fixing pins 6 for fixing the three core components 4a, 4b, and 4c, and a core retainer plate 7 having six fixing pin insertion slits 8 for inserting the six core fixing pins 6 and capable of rotating to release the core fixing pins 6 at the open position. The core retainer plate 7 is disc-shaped and has a central hole 7a formed in the center.

The fixing pin insertion slit 8 of the core retaining plate 7 has a width WA narrower than the maximum diameter Dmax of the core fixing pin 6 at the locked position A (WA<Dmax), and a width WB at the open position B larger than the maximum diameter Dmax of the core fixing pin 6 (WB>Dmax). For example, in the range of the locked position A, the fixing pin insertion slit 8 is formed with a retainer portion 8a that is narrower than the open position B. As shown in FIG. As described above, in this embodiment, the core fixing pin 6 can be released at the open position B and the core fixing pin 6 can be retained at the lock position A with a simple configuration. Further, the core retainer plate 7 is formed with an arc-shaped second push rod insertion slit 7c through which the second push rod 22 is inserted.

The mold 1 also includes a plate drive mechanism 10 that rotates the core retainer plate 7 . The plate drive mechanism may be a motor or an angular pin.

The plate drive mechanism 10 includes a drive plate 11 provided below the core retainer plate 7 for rotating the core retainer plate 7 . As shown in FIG. 4C, the drive plate 11 has a disk shape and a cylindrical shaft 11a extending vertically from the center.

The mold 1 further includes a core fixing pin lock mechanism 20 that is pushed down by the upper mold 2 so that the core retaining plate 7 locks the core fixing pin 6 .

The core fixing pin lock mechanism 20 includes, for example, a cylindrical first push rod 21 that is pushed down by the upper mold 2 to lock the core fixing pin 6 with the core retaining plate 7, and a second push rod 22 that is pushed down by the upper mold 2 to drive the drive plate 11, for example a cylindrical push rod.

The core fixing pin lock mechanism 20 also includes a first biasing member 23, for example, a compression coil spring, which is provided on the lower surface side of the drive plate 11 and biases the drive plate 11 toward the upper die 2, and a second biasing member 24, which is provided on the upper surface side of the drive plate 11 and consists of, for example, a compression coil spring and pushes up the second push rod 22. In this embodiment, the first push rod 21 is pressed by the mold clamping force of the molding machine without providing an urging member. The first biasing member 23 and the second biasing member 24 may not be compression coil springs, and may be plate springs, disc springs, air cylinders, or the like.

The first timing at which the first push rod 21 unlocks the core fixing pin 6 of the core retainer plate 7 is set to be simultaneous with or earlier than the second timing at which the second push rod 22 starts driving the drive plate 11.例文帳に追加

The plate drive mechanism 10 further has a rotation drive section 12 that rotates the core retainer plate 7 when the lock by the core fixing pin lock mechanism 20 is released.

For example, as shown in FIG. 1A or FIG. 4A, the rotation drive portion 12 is a ball member 13 provided between the shaft 11a of the drive plate 11 and the center hole 7a of the core retainer plate 7 through which the shaft 11a of the drive plate 11 is inserted. As shown in FIG. 1, the center hole 7a of the core retainer plate 7 is formed with a ball member accommodating recess 7b in which the ball member 13 is accommodated.

On the other hand, as shown in FIG. 4C, the shaft 11a of the drive plate 11 is spirally formed with a drive groove 11b in which the ball member 13 can move.

As shown in FIG. 1A or FIG. 4A, the core 4 has an upper core component 4a whose upper end has an outer diameter larger than that of its lower end, and a lower core component 4b which has a central through-hole through which the lower side of the upper core component 4a is inserted and whose upper end has an outer diameter larger than its lower end. In this embodiment, a ring-shaped outer core component 4c covers the lower outer periphery of the lower core component 4b. An undercut portion 5a of the molded product 5 is formed in a cavity 50 between the upper core component 4a, the lower core component 4b, and the outer core component 4c.

Next, the operation of the mold 1 according to this embodiment will be described in order using the drawings.

In the clamped state shown in FIG. 1, for example, a rubber product as the molded product 5 is formed from the silicone rubber in the cavity 50. As shown in FIG.

Then, as shown in FIG. 2, the mold opening process is started. First, when the upper die 2 is slowly raised, the upper die 2 is slightly separated from the lower die 3 and the force of the first push rod 21 pushing against the core retainer plate 7 is weakened. As a result, the locking of the core fixing pin is released at the first timing.

Next, as shown in FIG. 3, when the upper die 2 is further raised, the force with which the second push rod 22 presses the drive plate 11 via the second biasing member 24 is weakened. As a result, the drive plate 11 starts rotating at the second timing. Note that the second timing may be the same as the first timing.

Next, as shown in FIGS. 4A and 4B, the first biasing member 23 pushes the drive plate 11 up. As the drive plate 11 moves upward, the core retainer plate 7 rotates while the ball member 13 moves within the drive groove 11b. Specifically, the ball member 13 rotates the core retainer plate 7 in the direction of the arrow shown in FIG. 4B by moving the drive groove 11b shown in FIG. 4C from the lower side to the upper side. At this stage, each core fixing pin 6 is in the range of the lock position A, so that it is retained by the narrow retaining portion 8a of the fixing pin insertion slit 8. As shown in FIG. By providing the second push rod insertion slit 7c, the rotation of the core retainer plate 7 is not hindered.

Further, as shown in FIGS. 5A and 5B , the drive plate 11 is pushed up by the first biasing member 23 to further rotate the core retainer plate 7 and move the core fixing pin 6 to the open position B. As shown in FIGS. At this open position B, the core fixing pin 6 can be pulled out upward. Although not shown in detail, an ejector plate having an ejector rod erected vertically may be provided below the lower die 3 and operated in the direction of the upper die 2 to push up the core fixing pin 6 and remove the product from the core 4.

Next, as shown in FIG. 6, by moving the upper mold 2 away from the lower mold 3, the core 4 can be accessed from above.

Next, as shown in FIG. 7, the core 4 as a whole is separated from the lower mold 3 together with the molded product 5 . The core fixing pin 6 is lifted with each core component.

Then, as shown in FIG. 8, the outer core component 4c is removed from below. The molded product is a rubber product such as silicon rubber, and the undercut portion 5a is deformable, so that the molded product 5 is not damaged even if it is removed.

Next, as shown in FIG. 9, the lower core component 4b is removed from below.

Finally, the molded product 5 is removed from the upper core component 4a. In this way, when the drive plate 11 is pushed up by the first biasing member 23 in a state in which the lock by the core fixing pin lock mechanism 20 is released, the ball member 13 moves along the spiral drive groove 11b, so that the core retainer plate 7 rotates accordingly. Thereby, the core fixing pin 6 is moved to the open position B, and the core components 4a, 4b, 4c can be disassembled.

Conversely, in order to reassemble the mold 1 that has been disassembled, the operations described above may be performed in reverse order. At the time of assembly, when the core retaining plate 7 is set so that the core fixing pin 6 comes to the open position B and the upper die 2 is placed and pushed in, the core retaining plate 7 is pushed by the first push rod 21 and rotated, so that the mold 1 is assembled in a state in which the core fixing pin 6 is relatively moved to the lock position A and retained.

After assembly, it is preferable to use a communication passage (not shown) that communicates with the cavity 50 to fill the molded product 5 with a molding material. Since the mold 1 can be easily disassembled without taking much time, the core components are difficult to cool down and the difference in thermal expansion is small, so that the cores can be assembled normally.

Thus, in the present embodiment, by sequentially releasing the first push rod 21 and the second push rod 22 that have been pushed down by the upper die 2, the lock of the core fixing pin 6 of the core retainer plate 7 is released, and then the drive plate 11 is driven to rotate the core retainer plate 7 to the open position B. Then, when the core fixing pin 6 is moved to an open position where it can be opened, the plurality of core components 4a, 4b, 4c can be disassembled and the molded product 5 can be taken out without disassembling the entire mold.

In the present embodiment, even if the molded product 5 has ribs on the inner peripheral surface that will serve as the undercut portions 5a, the molded product 5 can be removed after molding without disassembling the mold 1 as a whole. Therefore, according to the mold 1 according to the present embodiment, even if the molded product 5 has the undercut portion 5a, the core can be easily disassembled and the molded product 5 can be taken out while suppressing the occurrence of the parting line.

-Modification-
Although not shown in detail, the configuration of the plate driving mechanism 10 is not limited to that of the first embodiment. For example, the rotation drive portion 12 may be a protrusion provided on the shaft 11a of the drive plate 11, and the core retainer plate 7 may have a central hole 7a through which the shaft 11a of the drive plate 11 is inserted and a drive groove 11b formed spirally on the inner peripheral surface thereof, into which the protrusion is inserted. In short, the concave-convex relationship is opposite to that of the above-described embodiment.

In this case as well, when the drive plate 11 is pushed up by the first biasing member 23 in a state in which the locking by the core fixing pin lock mechanism 20 is released, the protrusion of the shaft 11a of the drive plate 11 moves relatively along the spiral groove and pushes up the core retaining plate 7, so that the core retaining plate 7 rotates accordingly. Thereby, the core fixing pin 6 is moved to the open position B, and the core components 4a, 4b, 4c can be disassembled.

(Embodiment 2)
FIG. 10 shows Embodiment 2 of the present invention, which differs from Embodiment 1 in that the core retainer plate does not rotate but moves horizontally. In the following embodiment 2 and its modification, the same parts as those in FIGS. 1 to 9 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the mold of this embodiment (only the lower mold 103 portion is shown), the plate driving mechanism 10 has a horizontal driving portion that horizontally moves the core retainer plate 107 when the locking by the core fixing pin locking mechanism 20 is released. Although not shown in detail, the horizontal driving portion includes an inclined surface provided on one of the drive plate and the core retaining plate 107, and a protrusion provided on the other of the driving plate and the core retaining plate 107 and abutting on the inclined surface.

Also in this embodiment, the core retainer plate 107 can be moved horizontally from the locked position to the open position with a simple structure, and the core fixing pin 6 can be locked and unlocked.

-Modification-
FIG. 11 shows a mold according to a modification of Embodiment 2 of the present invention (only the lower mold 103' portion is shown), which differs from Embodiment 2 in that the core retainer plate 107' is divided into four parts.

In this case, it is preferable to move the core fixing pin 6 from the locked position to the open position by moving the two pairs of core retaining plates 107' away from each other. For example, two pairs of inclined surfaces and two pairs of protrusions may be provided.

(Other embodiments)
Embodiments of the present invention may be configured as follows.

That is, in the embodiment, the undercut portion 5a of the molded product 5 has a rib shape provided on the inner peripheral surface side, but it may be a rib shape provided on the outer peripheral surface side. In this case, the shape and arrangement of the core components may be changed according to the shape of the undercut portion. The core fixing pins may also be provided according to the shape and arrangement of the core components.

For example, modifications simply shown in FIGS. 12(a) to 12(c) can be considered. That is, as shown in FIG. 12(a), the inner peripheral surface of the undercut portion 205a of the molded product 205 may be formed by the projecting portions of the upper core component 204a and the lower core component 204b. As shown in FIG. 12B, the inner peripheral surface of the undercut portion 205a of the molded product 205 may be formed by the projecting portion of the lower core component 204b, or as shown in FIG.

In each of the above-described embodiments, the molded product 5 is a rubber product such as silicon rubber, but may be an elastomer having elasticity, or may be a thermoplastic resin material or a thermosetting resin material.

The above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its applications, or uses.

1 mold
2 upper die
3 lower die
4 core
4a upper core component
4b lower core component
4c outer core component
5 molded product
5a Undercut part
6 Core fixing pin
7 Core retainer plate
7a central hole
7b ball member housing recess
7c Second push rod insertion slit
8 Slit for fixing pin insertion
8a retaining part
10 plate drive mechanism
11 drive plate
11a axis
11b drive groove
12 rotary drive
13 ball member
20 Core fixing pin lock mechanism
21 first push rod
22 second push rod
23 first biasing member
24 second biasing member
50 cavity 103, 103' lower mold 107, 107' plate 204a upper core component 204b lower core component 205 molded product 205a undercut

Claims (5)

A mold for molding a molded product having an undercut portion, comprising an upper mold, a lower mold, and a core facing a cavity between the upper mold and the lower mold and composed of a plurality of core components,
a core fixing pin for fixing each of the plurality of core components;
a core retainer plate that has a plurality of slits for inserting the core fixing pins, locks the core fixing pins at a locked position, and can be opened at an open position that is rotationally or horizontally moved from the locked position;
a plate drive mechanism for rotating or horizontally moving the core retainer plate ,
A mold , wherein the plurality of core components are detachable via the core fixing pin . A mold for molding a molded product having an undercut portion, comprising an upper mold, a lower mold, and a core facing a cavity between the upper mold and the lower mold and composed of a plurality of core components,
a core fixing pin for fixing each of the plurality of core components;
a core retainer plate that has a plurality of slits for inserting the core fixing pins, locks the core fixing pins at a locked position, and can be opened at an open position that is rotationally or horizontally moved from the locked position;
a plate drive mechanism for rotating or horizontally moving the core retainer plate,
A mold, wherein the width of the fixing pin insertion slit of the core retaining plate is narrower than the maximum diameter of the core fixing pin at the locked position and wider than the maximum diameter of the core fixing pin at the open position. A mold for molding a molded product having an undercut portion, comprising an upper mold, a lower mold, and a core facing a cavity between the upper mold and the lower mold and composed of a plurality of core components,
a core fixing pin for fixing each of the plurality of core components;
a core retainer plate that has a plurality of slits for inserting the core fixing pins, locks the core fixing pins at a locked position, and can be opened at an open position rotated from the locked position;
a plate drive mechanism for rotating the core retainer plate,
The plate drive mechanism has a rotary drive unit that rotates the core retainer plate,
A mold characterized in that the rotary driving part has a mechanism in which a driving plate is connected to a core retainer plate by a shaft, and the core retainer plate is rotated by moving in the direction of the rotation axis. A mold for molding a molded product having an undercut portion, comprising an upper mold, a lower mold, and a core facing a cavity between the upper mold and the lower mold and composed of a plurality of core components,
a core fixing pin for fixing each of the plurality of core components;
a core retainer plate that has a plurality of slits for inserting the core fixing pins, locks the core fixing pins at a locked position, and can be opened at an open position that is rotationally or horizontally moved from the locked position;
a plate drive mechanism for rotating or horizontally moving the core retainer plate,
The above core is
an upper core component having an outer diameter at its upper end greater than an outer diameter at its lower end;
a lower core component having a central through hole through which the lower side of the upper core component is inserted, the outer diameter of the upper end being larger than the outer diameter of the lower end;
A mold, wherein an undercut portion of the molded article is formed in a cavity between the upper core component and the lower core component. upper mold;
lower mold;
a core facing the cavity between the upper and lower molds and comprising a plurality of core components;
a core fixing pin for fixing each of the plurality of core components;
a core retainer plate that has a plurality of slits for inserting the core fixing pins, locks the core fixing pins at a locked position, and can be opened at an open position that is rotationally or horizontally moved from the locked position;
a plate driving mechanism for rotating or horizontally moving the core retainer plate,
Prepare a mold for molding a molded product having an undercut,
After closing the upper mold and lower mold and forming the molded product inside the cavity formed by the upper mold, the lower mold and the core with the core fixing pin in the fixed position,
Open the upper die, unlock the core retainer plate, and at the same time or after that,
starting rotational movement or horizontal movement of the core retainer plate;
moving the core fixing pin to the open position of the core retaining plate to open the core retaining plate;
Separating the core from the lower mold together with the molded product,
Taking out the molded product while sequentially removing the plurality of core components
A molding method for a molded product having an undercut portion, characterized in that:

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