JP3197926B2 - Injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine, and more particularly to an injection molding machine capable of sequentially performing injection and filling operations on a plurality of injection molding dies.

[0002]

2. Description of the Related Art A so-called rotary molding machine is conventionally known as this type of injection molding machine. This injection molding machine
It has an annular mold mounting part to which a plurality of injection molding dies can be attached, and the upper part of the injection molding die,
By fixing one of the lower mold, the core side, and the cavity side, and rotating the mold mounting portion to inject and fill the resin into the injection mold that has reached a predetermined position, a plurality of injection molds are provided. Is filled with resin.

Incidentally, the pressure in the cavity of the injection mold is 1300 kg / cm 2 immediately after filling the molten resin.
However, after the elapse of about 3 minutes, the resin temperature decreases until it becomes equal to the mold temperature, and the pressure in the cavity also decreases to about 300 kg / cm 2. With such a pressure, the mold can be separated from the injection unit only by clamping the mold so that the parting surface does not separate. Therefore, recently, after injection into the mold unit,
Attempts have been made to improve the molding efficiency by providing a self-holding mechanism and a gate seal mechanism for holding a required mold clamping force after 3 minutes have elapsed so that the mold is separated from the injection unit during cooling.

[0004]

However, in such a conventional injection molding machine, a mold clamping mechanism is provided only at the predetermined position where the injection and filling operations are performed.
If a gate seal mechanism is added to the injection mold, the injection unit can be separated from the mold early and the next injection operation can be performed, but the pressure in the cavity drops to a predetermined pressure after the completion of resin injection. Until the injection unit could be used for a long time, the efficiency of the injection / filling operation was poor.

Accordingly, the present invention improves the working efficiency of the injection unit by separating the injection unit from the mold while maintaining the mold clamping force at the time of injection so that the next injection operation can be performed during mold clamping. The purpose is to:

[0006]

In order to achieve the above object, according to the present invention, a plurality of injection molds each forming a cavity, and the injection molds are connected to a predetermined heating station, an injection station, The injection molding system is provided with an injection molding system having a conveying means for conveying the cooling unit in the order of a slow cooling station and a molded product taking out station, and a plurality of injection molds conveyed to the injection station are mounted on a predetermined mounting plate. a injection molding machine for injecting and filling the molten resin by the injection unit to the molding die cavity, each to all attachment points of the mounting plate, wherein the plurality of injection mold is attached the injection mold A mold clamping mechanism is provided.

[0007]

[0008]

According to the first aspect of the present invention, a mold clamping mechanism is provided at each of the mounting positions of the mounting plate on which a plurality of injection molding dies are mounted, and the molten resin is placed in the cavity of the die mounted on the mounting plate. When injection and filling are performed, the mold clamping and the timing of the injection and filling operation can be controlled independently. Therefore, the injection unit can be separated from the mold while maintaining the mold clamping force at the time of injection, and the operation can be shifted to the next injection operation during cooling, thereby improving work efficiency.

[0009]

[0010]

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 6 are views showing an embodiment of an injection molding machine according to the present invention. First, the configuration will be described. 1 to 4
In the figure, reference numeral 10 denotes four gate-sealable injection molding dies (described later) in each of which a cavity 10a is formed by a pair of mold members 11 and 12, and these injection molding dies 10 are rotary mounting plates. Installed at equal angular intervals to 20.
A well-known injection unit 30 and a mold carrying-in / discharge path 40 are provided near the rotary mounting plate 20, and the injection unit 30 is injected into the injection molding die 10 moved to a predetermined position with the rotation of the rotary mounting plate 20. The unit 30 is configured to inject and fill the molten resin. That is, in this embodiment, a plurality of injection molds 10
The molten resin is injected and filled into the cavity 10a of the injection molding die 10 in a state where is mounted on a predetermined mounting plate 20. Also,
The mold loading / unloading path 40 is provided at a predetermined heating station, injection station (not shown) for the injection molding die 10 (not shown).
Above), a part of the conveying means for sequentially conveying the cooling station and the molded product taking-out station in this order, and a gate seal injection molding system capable of performing a continuous molding operation by this conveying means and the respective stations. It is configured.

Although not shown in detail, in this molding system, a plurality of injection molding dies 10 are conveyed by conveying means such as a chain, first heated in a heating station, and then sent to an injection station. The molten resin is injected and filled into the cavity 10a, and the gate is sealed.The temperature and pressure of the cavity 10a are reduced, and then the cavities 10a are conveyed to a slow cooling station where they are gradually cooled to a heat deformation temperature or lower. It is designed to be opened.

The rotary mounting board 20 is provided with a mold clamping mechanism 50 at each of all mounting locations where a plurality of injection molds 10 are mounted. As shown in FIG. 2, the mold clamping mechanism 50 includes mold plates 51 and 52 and a mold clamping member 53 driven by a hydraulic cylinder or the like to bring the mold plate 52 close to the mold plate 51.
It is a known hydraulic system that clamps 11 and 12 in the mold clamping direction, and can exert a sufficient mold clamping force against the pressure in the cavity immediately after the injection of the injection unit 30 (at the time of gate sealing described later). . In addition, the plurality of mold clamping mechanisms 50
Is a rotary type which is supported by the rotary mounting plate 20 and rotates integrally therewith.

The plurality of mold clamping mechanisms 50 include an injection unit
When the rotary mounting plate 20 is rotated in accordance with the operation timing of 30, the rotary mounting plate 20 is operated at a predetermined timing different for each mounting position (described later), and the resin pressure in the cavity 10 a has been approximately 300 kgf / cm 2 or more since the injection. The injection molding die 10 is clamped until a lapse of two to three minutes after the completion of the injection and filling. After two to three minutes have passed since the injection and filling of the molten resin into the cavity 10a by the injection unit 30, the injection molding die 10 whose mold clamping force has been released is transferred to the carry-in / discharge path 40 by a transfer means (not shown). Transferred and discharged.

The injection mold 10 has a self-holding mechanism 60.
Immediately after the release of the mold clamping force by the mold clamping mechanism 50, a predetermined mold clamping force (approximately 3
A mold clamping force for maintaining the mold clamping state with respect to the pressure in the cavity of about 00 kgf / cm 2 can be maintained. Specifically, as shown in FIGS.
60 has a plurality of (for example, four) self-holding bolts 61 for connecting the mold members 11 and 12 by tightening them in the mold-clamping direction in the vicinity of the cavity 10a. And screwed to the mold member 12. By using the self-holding mechanism 60, the gate portion 10b of the injection mold 10 is moved to the gate portion 10 after the resin is filled by the injection unit 30.
When the gate is sealed by a bolt 70 having a hole intersecting with b, the injection unit 30 is separated from the injection molding die 10 and a predetermined pressure-holding state is maintained. In addition,
As shown in FIG. 3, at the time of injection and filling, the bolt 70 with the hole is loosened so that the hole 70a of the bolt 70 with the hole is communicated with the front and rear gate portions 10b.

Next, the operation will be described. First, the mold members 11, 12 of the injection mold 10 are closed in advance, and then
A plurality of self-holding bolts 61 are tightened by the mold opening / closing device 52 of the molded product take-out station 50, and bolts 70 with holes for gate sealing are attached as shown in FIG. The mold is clamped so that it can be held.

Next, after the injection molding die 10 is uniformly heated to a predetermined temperature in a heating station, the injection molding die 10 is carried onto a rotary mounting plate 20 which is an injection station, and the injection molding die 10 at a predetermined position is clamped. The mold is clamped by the mechanism 50. In this state, the injection unit 30 injects and fills the molten resin into the cavity 10a in the injection mold 10 through the gate 10b. When the injection is completed, the bolt 70 with the hole is rotated in the tightening direction, and as shown in FIG.
The gate seal of b is performed.

A predetermined time after the completion of the gate sealing operation,
For example, after elapse of 30 seconds, the injection unit 30 is separated from the injection mold 10 while the mold clamping by the mold clamping mechanism 50 and the gate sealing are performed, that is, in a state where a required cavity pressure is secured. When the rotary mounting plate 20 is retracted and rotated by a predetermined angle, the injection molding die 10 to be injected / filled next reaches the predetermined position (injection / filling position). Therefore, injection and filling operations can be performed several times in a short time, and the operation rate of the injection unit 30 can be increased. As a result, the work efficiency is greatly improved as compared with the conventional method, in which the main mold clamping is performed only at the injection / filling position, and the mold clamping state is maintained until the pressure in the cavity that can be self-retained is reached (2 to 3 minutes). Can be improved.

On the other hand, during this time, the injection mold 10 is moved downstream from the predetermined position after the injection / filling operation is completed.
Means that the resin pressure in the cavity 10a is approximately 300 kgf / cm
Since it is 2 or more and the internal resin has a high temperature and a low viscosity, burrs are generated if the mold clamping force is insufficient. However, the mold clamping mechanism 50 exerts a sufficient mold clamping force against the pressure in the cavity immediately after the gate seal (instantaneously reaches about 1300 kgf / cm 2), so that generation of burrs is ensured. Injection unit 30
There is no sudden pressure change when disconnecting from Therefore, in this clamped state, the predetermined temperature equal to or higher than the glass transition point is maintained for a necessary time, and the pressure of the resin in the injection molding die 10
The uneven distribution of temperature can be sufficiently reduced.

In addition, the injection / filling operation and the rotary mounting plate 20
When the rotation is repeated, the injection-molded mold 10 that has been injected and filled moves downstream, and finally reaches a position facing the mold carry-in / discharge path 40. At this time, the injection mold 10
The resin pressure inside has decreased to about 300 kgf / cm 2 or less. Next, the mold clamping force of the mold clamping mechanism 50 at that position is released, and the mold clamping force of the self-holding mechanism 60 acts on the injection molding die 10. As described above, each mold clamping mechanism 50 moves the corresponding injection molding die 10 to the predetermined position (injection / filling position).
It operates only after reaching the position and before reaching the position facing the mold loading / unloading path 40. That is, each mold clamping mechanism 50 operates at a predetermined timing that differs for each mounting location where the injection mold 10 is mounted.

Next, the injection mold 10 at a position facing the mold carry-in / discharge path 40 is moved by the transfer means to the mold carry-in / discharge path.
It is transferred to 40, discharged to the slow cooling station, and slow cooled independently. At this time, since the injection-molding mold 10 to be gradually cooled can be tightened by the self-holding bolt 61 to maintain a predetermined mold clamping force, it can be gradually cooled in a desired pressure state. Therefore, the transfer surface shape (the surface forming the cavity 10a) formed on the mold members 11, 12 of the injection mold 10 is transferred with high precision. In the slow cooling station, for example, while performing pneumatic slow cooling, the injection molding die 10 is moved by a set number of counts at a constant speed by a part of the conveying means, or is stopped for a set stop time.

When the resin inside the injection mold 10 is solidified by the slow cooling (cooled to a temperature lower than the thermal deformation temperature), and the injection mold 10 is transported to the molded product take-out station, the self-holding bolt 61 is loosened. Then, the mold opening of the injection mold 10 is performed. Then, the solidified molded product is taken out of the injection molding die 10 by, for example, the take-out type take-out device.

As described above, in the present embodiment, by employing the rotary-type mold clamping mechanism 50, the injection unit 30 and the injection molding metal are kept in the mold-clamped state by the mold clamping mechanism 50 within a short time after the gate seal is completed. Since the mold 10 is separated and the mold injection mechanism 30 and the rotary mounting plate 20 are rotated together to perform the next injection and filling work, the operation rate of the injection unit 30 can be increased and the work efficiency can be greatly improved. can do.

In this embodiment, the self-holding and the gate sealing are performed by using bolts. However, such a mechanism can be replaced with, for example, one shown in FIGS. In both figures, reference numeral 81 denotes a U-shaped self-holding mold-clamping member. The self-holding mold-clamping member 81 is an engaging portion 81 inserted into a hole 91a of a mold member 91 of an injection mold 90.
a and an engaging portion 81b inserted into the hole 92a of the mold member 92. The inner wall portion of the engaging portion 81a of the self-holding mold clamping member 81 is tapered so that the engaging portion 81a becomes thinner toward the distal end, and the two insertion portions 81a and 81b are connected to the injection molding die 90.
When inserting the mold, the mold is clamped by a so-called wedge effect. When the self-holding mold clamping member 81 is inserted, the cavity 90a of the injection mold 90 is engaged with the engaging portion 81b.
The gate portion 90b communicating with the port is closed (sealed).

7 to 12 show another embodiment of the injection molding machine according to the present invention. Note that in the present embodiment, the same reference numerals are used for the configurations of members that are the same as or correspond to those in the above-described example, and redundant description is omitted. 7 and 8, two injection molding dies 110 are mounted on a rotary mounting plate 120, and a mold clamping mechanism 50 is provided at each die mounting portion of the rotary mounting plate 20. Also, 2
A pressing mechanism 150 that presses the injection mold 110 in a direction orthogonal to the mold clamping direction is provided at each of the two mold mounting locations. The pressing mechanism 150 includes, for example, a first block body 151 supported by a pair of tie bars 55 and 56 of the mold clamping mechanism 50,
It has a second block body 152 supported by a pair of tie bars 57, 58 of the mold clamping mechanism 50, and pressing bolts 153, 154 screwed to the block bodies 151, 152, respectively.
By pressing the tips of 153 and 154 against the side wall surface of the mold 110 near the contact surfaces of the mold members 111 and 112, the injection molding mold 110 is pressed from a direction orthogonal to the mold clamping mechanism 50. Has become.

The pressing mechanism 150 is driven by a known rotary driving means (not shown) so as to press the injection mold 10 only during the mold clamping by the mold clamping mechanism 50, for example. It operates at a different timing for each of the mounting locations where the molding die 10 is mounted. Mold clamping mechanism 50 for injection time for each mold
The operation timing of the pressing mechanism 150 is as shown in the timing chart of FIG. 9, and the time for applying the side clamping force by the pressing mechanism 150 is during mold clamping and shorter than the mold clamping time.

As described above, in the present embodiment, the pressing mechanism 150 is provided, and when the resin is injected and filled into the injection mold 110,
The injection molding die 110 is pressed in a direction orthogonal to the direction of clamping. Therefore, the cavity 110 of the injection mold 110 is
Although the shape of a is strip-shaped and the projection area of the pressing bolts 153 and 154 projected in the axial direction is large, the deformation of the mold members 111 and 112 to the side at the time of injection and filling is suppressed. It can be made hard to occur, and the molding accuracy can be improved.

As another mode of the pressing mechanism, FIG.
The one shown in FIG. In the figure, 250
Is a pressing mechanism, and this pressing mechanism 250
Has four pressing blocks 251 that abut against each side wall surface. A hydraulic cylinder 252 is mounted on each pressing block 251, and by extending the hydraulic cylinder 252, a reaction force is generated on the tie bars 55 to 58 to press the mold 110 in a direction orthogonal to the mold clamping direction. It has become.

FIGS. 11 and 12 show still another embodiment.
The following can be considered. In both figures, 350 is provided between the mold plates 51 and 52 of the mold clamping mechanism 50 and the injection mold 31 is provided.
0 is a pair of pressing mechanisms opposing each other with one mold member 311 interposed therebetween (only one of the pressing mechanisms is shown in the drawing), and each pressing mechanism 350 is a third pressing mechanism fixed to the template 51 or 52. One support member 351, a second support member 352 that contacts and separates from the template 52 or 51, and one end is pivotally connected to the support members 351 and 352, and the other end is freely rotatable with each other. It has a pair of linked link members 353 and 354. The mold member 311 has a concave portion 311a for forming a cavity, and has a shape that is easily deformed. When the mold plates 51, 52 move in the mold clamping direction, the link members 353, 354 of the pair of pressing mechanisms 350 press against the pair of side wall surfaces of the mold 310 at the other end portions, thereby orthogonally to the mold clamping direction. The mold 310 is pressed in the direction to be pressed.

In this way, a simple pressing mechanism that generates a pressing force in conjunction with mold clamping can be realized.

[0031]

According to the first aspect of the present invention, a mold clamping mechanism is provided at each of all the mounting locations of the mounting plate on which a plurality of injection molding dies are mounted. Can be controlled independently of timing,
The injection unit can be separated from the mold while maintaining the mold clamping force during injection. As a result, the injection unit that has completed the injection can be transferred to the next injection operation while the injected mold is being cooled, and the efficiency of the molding operation can be significantly improved.

[0032]

[0033]

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of an injection molding machine according to the present invention.

FIG. 2 is a front sectional view of a mold clamping mechanism and a mold according to one embodiment.

FIG. 3 is an enlarged cross-sectional view of the vicinity of a gate portion of a mold, showing a state where the gate is opened.

FIG. 4 is an enlarged cross-sectional view of the vicinity of a gate portion of a mold, showing a state where the gate is sealed.

FIG. 5 is a front sectional view showing another embodiment of the mold and the self-holding mechanism.

FIG. 6 is a perspective view showing another embodiment of the mold and the self-holding mechanism.

FIG. 7 is a perspective view showing a schematic configuration of another embodiment of the injection molding machine according to the present invention.

FIG. 8 is a diagram showing the configuration of the mold clamping mechanism and the pressing mechanism,
(A) is a partial cross-sectional front view, (b) is XX of (a)
It is sectional drawing.

FIG. 9 is a timing chart showing timings of mold clamping by a mold clamping mechanism and side clamps by a pressing mechanism with respect to an injection timing operation.

FIG. 10 is a sectional view showing another mode of the pressing mechanism.

FIG. 11 is a front view showing still another mode of the pressing mechanism.

FIG. 12 is a cross-sectional view of an example of a mold to which the pressing mechanism is applied.

[Explanation of symbols]

 10, 90, 110, 310 Injection molds 11, 12, 91, 92, 111, 112, 311 A pair of mold members 20, 120 Rotary mounting plate 30 Injection unit 40 Mold loading / discharging passage 10a, 90a, 110a Cavity 50 Mold clamping mechanism 60 Self-holding mechanism 10b, 90b Gate 70 Bolt with hole 81 Self-holding mold clamping member 150, 250, 350 Pressing mechanism

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Fukushima 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Toshiharu Hatakeyama 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Kinichi Oikawa, Inventor, Ricoh Optical Co., Ltd., 109, Ohata 10th Land, Hanamaki City, Iwate Prefecture (56) References 39222 (JP, A) JP-A-3-34831 (JP, A) JP-A 2-22018 (JP, A) JP-A-3-126515 (JP, A) JP-A 5-162166 (JP, A) Japanese Patent Publication 3-65772 (JP, B2) Japanese Patent Publication 6-28886 (JP, B2) Japanese Patent Publication 4-19010 (JP, B2) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84 B29C 33/00-33/76

Claims (1)

(57) [Claims] A plurality of injection molds each forming a cavity, and a conveying means for conveying the injection molds in the order of a predetermined heating station, an injection station, a slow cooling station, and a molded product removal station. A plurality of injection molds conveyed to the injection station are mounted on a predetermined mounting board, and a molten resin is injected and filled into a cavity of the injection mold by an injection unit. An injection molding machine, wherein the injection molding dies are clamped at all of the mounting positions of the mounting plate on which the plurality of injection molding dies are mounted .
Injection molding machine, characterized in that a that clamping mechanism.