JPH08174605A - Molding apparatus - Google Patents

Abstract

PURPOSE: To synchronize surely the motion of each nozzle by a simple constitution, to suppress restriction of mold-working region to be caused a nozzle switching apparatus and to make the operation for exchanging a step convenient in a molding apparatus with a plurality of nozzles. CONSTITUTION: A molding apparatus 10 is provided with a hot runner block 3 for feeding a molten resin to be filled in a cavity formed by a pair of molds 1 and 2, a plurality of nozzles 11 installed in the communicating part of the hot runner block 3 and the cavity C to feed/shut-off the molten resin into the cavity C, a valve switching apparatus 13 for switching the nozzles 11 by reciprocating valve pins 11b constituting the nozzles 11, and a clamping mechanism for switching the molds 1 and 2. The valve switching apparatus 13 consists of a movable member 14 connected with each valve pin 11b and a driving means 15 provided on a fixed stage 9 of the clamping mechanism and for moving the movable member 14 in the switching direction of the nozzles 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve opening / closing type molding apparatus.

[0002]

2. Description of the Related Art A valve opening / closing type injection molding apparatus having a cylinder accommodating a piston to which one end of a valve pin is connected reciprocally has been widely put into practical use, and a cylinder is arranged for each mold forming a cavity. The configured one is
It is disclosed in Japanese Patent Publication No. 3-54611. Further, there is also a molding apparatus including a plurality of cavities and configured to mold a plurality of products in one molding cycle.

A conventional molding apparatus of this type has been proposed, for example, in Japanese Utility Model Publication No. 50-10465. As shown in FIG. 2, this molding apparatus includes a mold 1 and a mold 2 having a plurality of cavities C, and a hot runner block 3 for supplying a molten resin filled in each of the cavities C, C. A plurality of nozzles 4 and 4 for supplying and blocking the molten resin from the hot runner block 3 to the cavities C and C, and a plurality of valve opening and closing devices 5 and 5 for opening and closing the nozzles 4 and 4. The plasticizer 6 is provided to plasticize the raw material and send the melted resin to the hot runner block 3.

Further, the nozzle 4 is integrated with the hot runner block 3 to form a hot runner device, and a nozzle main body 4a which is brought into contact with the die 2 and a slidably mounted inside the nozzle main body 4a. , And a valve pin 4b that opens and closes the tip of the nozzle body 4a (contact portion with the mold) from the inside. Further, the valve opening / closing device 5 is composed of a hydraulic cylinder and is fixed to the hot runner block 3, and the piston 5a thereof is fixed to the valve pin 4b which penetrates the hot runner block 3 and projects to the outside. ing.

In the conventional molding device thus constructed, the resin plasticized by the plasticizing device 6 is inserted into the hot runner block 3 and the cavities C in the molds 1 and 2 which are clamped. It is filled through the resin passages 7 in the nozzle bodies 4a, 4a, but before the filling, the valve opening / closing devices 5, 5 are actuated and the valve pins 4b, 4b open the tips of the nozzle bodies 4a, 4a. To retreat,
The resin passage 7 is opened. After filling, the nozzles 4 and 4 are closed again by the valve opening and closing devices 5 and 5, respectively.
To prevent resin from flowing out. In the figure, 8 is a fixed plate of a mold clamping mechanism (not shown) that opens and closes the molds 1 and 2, and the fixed plate 8 has holes 8a, 8a for passing the nozzles 4, 4 respectively. Has been formed.

[0006]

By the way, in such a conventional molding apparatus, there are the following problems to be improved. That is, since one hydraulic cylinder has to be installed for one nozzle 4, the installation position of the nozzle 4 is limited by the pitch at which the nozzle opening / closing device 5 can be installed.
In a so-called multi-cavity mold in which one cavity C is formed for one nozzle 4, the cavity C
The processing position of is limited. In particular, when the product dimension is smaller than the pitch at which the nozzles 4 can be installed, the cavity C cannot be formed even though there is a space for forming the cavity C, and the moldable region cannot be effectively used. Becomes

Further, the plurality of nozzles 4 and 4 are opened and closed by the valve opening and closing devices 5 and 5 provided respectively, but the operating oil supplied to these valve opening and closing devices 5 and 5 is a single. Since the oil pressure is generated and supplied by the oil pressure generation source, there is a problem that the supply of the hydraulic oil to the valve opening / closing devices 5 and 5 tends to be uneven. When such a problem occurs, the opening and closing timings of the nozzles 4 and 4 deviate from each other, which causes variations in the filling amount of the molten resin in the cavities C and C and the pressure of the filled resin. Variation occurs, resulting in deterioration of molding accuracy. Further, since the valve opening / closing device 5 has to be provided for each nozzle 4, this causes a rise in the die manufacturing cost including the installation of the device main body, piping, signal lines, and the like.
Moreover, due to the installation of these many pipes and signal lines, it is necessary to replace them when replacing the mold, which is a cause of making the setup replacement complicated.

Therefore, it is an object of the present invention, in particular, to enable the operations of a plurality of nozzles to be reliably synchronized with each other by a simple structure, to suppress the restriction of the die machining area by the opening / closing device of the nozzles, and It is an object of the present invention to provide a molding device that can be easily replaced.

[0009]

In order to solve the above problems, the invention according to claim 1 provides a hot runner block for supplying a molten resin filled in a cavity formed by a pair of molds, and a hot runner block for this hot runner block. A nozzle that is provided in a communicating portion between the runner block and the cavity and that supplies and blocks molten resin to the cavity and a valve pin that constitutes this nozzle reciprocates to open and close the valve. A molding device comprising a device and a mold clamping mechanism for opening and closing the mold, wherein the valve opening and closing device is provided on a movable member to which the valve pins are connected, and on a fixed plate of the mold clamping mechanism. , A drive means for moving the movable member in the opening / closing direction of the nozzle.

Further, the invention according to claim 2 is the same as claim 1.
In the invention described above, a plurality of the nozzles are provided, and a plurality of the valve pins are connected to the movable member.

[0011]

According to the first aspect of the invention, the movable member is moved by the driving means provided on the fixed plate of the mold clamping mechanism, so that the valve pin connected to this movable member is opened and closed.

According to the second aspect of the invention, since each valve pin is rigidly connected through the movable member, each valve pin is moved as a unit, whereby all valve pins are synchronized. Is surely taken.
In addition, since the driving means is connected to each valve pin via the movable member, the driving means can be installed regardless of the installation position of the valve pin, thereby eliminating the restriction on the working area of the die. Further, since the driving means only moves the movable member, the number of installations can be suppressed to a minimum, and it can be installed on a fixed plate outside the mold, which facilitates maintenance and setup changes. Becomes

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the molding apparatus according to the present invention will be described below with reference to FIG. First, as shown in FIG. 1, the molding apparatus 10 includes a pair of molds 1 and 2, and the molds 1 and 1.
Hot runner block 3 for supplying molten resin filled in a plurality of cavities C formed between two, and a plurality of nozzles 11 provided in this hot runner block 3.
And a valve opening / closing device 13 that reciprocates the valve pin 11b. The valve opening / closing device 13 is provided on the movable member 14 including the plurality of valve pins 11b and the fixed plate 9 of the mold clamping mechanism, and the movable member 1 is provided.
4 and a drive means 15 for moving the same. In the figure, P. L is a parting line of the molds 1 and 2.

That is, the hot runner block 3 is a fixed platen 9 of a mold clamping mechanism (not shown) that opens and closes the molds 1 and 2.
Are fixed to the hot runner block 3 at predetermined intervals via a connecting block 12. The hot runner block 3 is provided corresponding to each cavity C, and the valve pin 11b.
Together with the plurality of nozzle bodies 11a forming the nozzle 11
Has been fixed. And each of these nozzle bodies 11
a and the hot runner block 3 have plasticizing means 6
A resin passage 7 that communicates with the resin and serves as a supply passage for the molten resin is continuously formed. The hot runner block 3 and the nozzle 11 are heated by a heater (not shown) or the like to prevent the molten resin from solidifying. The stationary platen 9 is formed with a hole 9a for connecting the nozzle portion at the tip of the plasticizing device 6 to the resin passage 7 of the hot runner block 3.

The connecting block 12 is for fixing the mold 2 and the hot runner block 3 to the fixed platen 9. The connecting block 12 has a space 12a in which the hot runner block 3 and the nozzle 11 are arranged, and the hot runner is formed. A gap 12b is formed between the block 3 and the fixed platen 9 to hold them at a position separated by a predetermined distance as described above. The gap 12b is adapted to communicate outward from the side of the fixed platen 9. And this gap 12
In b, while joining the plate 16 to the fixed plate 9,
The plate 17 is also joined to the connecting block 12 and the hot runner block 3 with the heat shield plate 18 interposed therebetween. further,
A heat shield plate 19 is interposed between the hot runner block 3 and the connection block 12 on the side opposite to the gap 12b.

On the other hand, the movable member 14 is formed in a plate shape in the embodiment and is arranged between the plates 16 and 17 in the gap 12b between the fixed platen 9 and the hot runner block 3, and a part of the gap is formed in the gap 12b. , And is opposed to the plate 16 joined to the fixed plate 9 outside the hot runner block 3. Further, each valve pin 11b fixed to this movable member 14 penetrates the hot runner block 3, the heat shield plate 18 and the plate 17 and projects toward the plate 16 side of the fixed platen 9. The radial end portion is fixed to the movable member 14 by an appropriate connecting means such as screwing or engagement using a collet. The movable member 14 may be two plates, and the large diameter end of the valve pin 11b may be sandwiched and fixed between them.

As the driving means 15, a fluid pressure cylinder is used in the embodiment, and the cylinder body 15a thereof is used.
Is fixed to the fixed platen 9, and one end portion of the piston rod 15b is fixed to a portion of the movable platen 14 which protrudes laterally from the gap 12b through the hole 9b of the fixed platen 9. . Since the driving means 15 should be moved in parallel with the fixed platen 9 when the movable member 14 is moved, it is preferable to provide the driving means 15 at both ends of the movable member 14, but the movable member 14 is moved in parallel by another method. If it can be moved, it may be one.

Further, the piston rod 1 of the driving means 15
The other end of 5b projects from the cylinder body 15a, and a pair of limit switches 20 and 21 is installed at a position facing the other end of the piston rod 15b. These limit switches 20 and 21 are composed of proximity switches and the like, and the fixed board 9
Is fixed via a bracket to the piston rod 15b.
By detecting the position of the piston rod 15b in cooperation with the other end of the movable member 14, the most advanced position and the most retracted position, that is, the most advanced position and the most retracted position of the movable member 14 are detected. There is.

Next, the operation of the molding apparatus 10 of the embodiment constructed as above will be described. By moving the movable member 14 toward the fixed platen 9 side by the driving means 15, each valve pin 11b is retracted and the nozzle body 1 is moved.
Open the tip of 1a. Prior to the main molding, blanking is performed several times to fill the resin passage 7 with the molten resin.
Next, after the molds 1 and 2 are clamped, the nozzle body 1
The respective cavities C are filled from the tip of 1a and molded. After the filling, the movable member 14 is moved to the hot runner block 3 side by the driving unit 15 to move the valve pins 11b forward so that the nozzle body 1
The tip of 1a is closed to prevent the resin from flowing out of the nozzle 11.

In such a molding operation, since all the valve pins 11b are rigidly connected through the movable member 14, all the valve pins 11b can be moved integrally. Moreover, since the movement of each valve pin 11b is guided by the nozzle body 11a and the movement in the oblique direction with respect to the center line thereof is restricted, each valve pin 11b is restrained.
The movement of b is almost a linear movement to prevent steadying. Therefore, the movement of each valve pin 11b is performed in synchronization, the opening / closing timing of each nozzle 11 is prevented from being shifted, and accordingly, the variation in the filling amount of the resin for each of the plurality of cavities C is suppressed. As a result, the molding accuracy can be improved.

Further, the movable member 14 to which the valve pins 11b are fixed has only the function of connecting the valve pins 11b to each other, and does not limit the distance between the valve pins 11b. 1
Driving means 15 for opening and closing 1b is connected to each of these valve pins 11b through a movable member 14,
Moreover, since it is installed at a position largely separated from the side parts of the molds 1 and 2, the valve opening / closing device 13 does not interfere with the installation position of the valve pin 11b. Therefore, the restriction on the formation pitch of the cavities C is reduced, and the workable region of the mold is effectively used. Further, the driving means 1
5 is positioned at the position of the fixing plate 9 exposed from the molding apparatus 10, and the number of installations is suppressed to a minimum, so that maintenance is easy and setup change work is simplified.

The shapes, dimensions, etc. of the respective constituent members shown in the above-described embodiment are merely examples, and can be variously changed based on design requirements. For example, in the embodiment, an example in which the limit switches 20 and 21 are used to control the operating position of the valve pin 11b has been shown, but instead of this, the surface of the hot runner block 3 or the fixed plate 9 facing the movable member 14 is replaced. The position regulating members are arranged on the movable member 14 and the movable member 14 is brought into contact with the position regulating members so as to regulate the forward and backward positions of the movable member 14, that is, the forward and backward positions of the valve pin 11b. It's okay. Further, in the embodiment, the molding apparatus provided with one cavity C for one nozzle 11 is illustrated, but the same applies to a molding apparatus in which a plurality of nozzles 11 are installed for one cavity C. Applicable. Furthermore, it goes without saying that the present invention can also be applied to a molding apparatus having one nozzle.

[0023]

As described above, according to the molding apparatus of the first aspect of the present invention, the movable member is moved by the driving means provided on the fixed plate of the mold clamping mechanism, and the valve pin connected to the movable member. Can be opened and closed. Therefore,
In the case of a molding apparatus having a plurality of nozzles, the operations of the plurality of nozzles can be surely synchronized with a simple configuration.

According to the molding apparatus of the second aspect of the present invention, by rigidly connecting the plurality of valve pins through the movable member, the movements of the respective valve pins during the molding operation are integrated, whereby all of them are integrated. The operation of the valve pins can be completely synchronized. As a result, it is possible to eliminate the time lag of the operation of each nozzle, perform molding closer to the planned value, and improve the molding accuracy. Further, by connecting the drive means and each valve pin via the movable member, the drive means can be installed regardless of the installation position of each valve pin, thereby reducing the workable area of the die. It is possible to suppress this and to effectively utilize this processable region. further,
In combination with the fact that the function of the driving means is integrated into the moving operation of the movable member, the number of installations can be suppressed to a minimum, and the above-mentioned restriction on the installation position can be eliminated, the molding device Not only can the structure be simplified, but the maintenance and setup work can be simplified.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part showing an embodiment of a molding apparatus of the present invention.

FIG. 2 is a vertical cross-sectional view of a main part showing a conventional molding device.

[Explanation of symbols]

 1, 2 Mold 3 Hot runner block 6 Plasticizing device 7 Resin passage 9 Fixing plate 10 Molding device 11 Nozzle 11a Nozzle body 11b Valve pin 12 Connecting block 13 Valve opening / closing device 14 Movable member 15 Driving means 16, 17 Plates 18, 19 Blocking Hot plate 20,21 Limit switch

Claims (2)

[Claims] 1. A hot runner block for supplying a molten resin to be filled in a cavity formed by a pair of molds, and a molten resin which is provided in a communicating portion between the hot runner block and the cavity and is provided in the cavity. And a valve for opening and closing the nozzle by reciprocating a valve pin forming the nozzle, and a mold clamping mechanism for opening and closing the mold. Wherein the valve opening / closing device includes a movable member to which the valve pin is connected, and a drive unit provided on a fixed plate of the mold clamping mechanism and configured to move the movable member in the opening / closing direction of the nozzle. Molding device characterized by being 2. The molding apparatus according to claim 1, wherein a plurality of the nozzles are provided and a plurality of the valve pins are connected to the movable member.