JPH085089B2 - Alternate 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 alternate injection molding machine capable of performing injection molding by alternately moving two sets of molds together with a sub-clamping mechanism having a mold opening / closing means.

[0002]

2. Description of the Related Art A pair of die sets (sub mold clamping mechanism) having mold opening / closing means at the top and bottom, guide means for moving the die sets laterally, and both of the sub mold clamping mechanisms are at stop positions. The vertical main mold clamping mechanism arranged in the central part, moving means for moving both sub mold clamping devices to alternately move the sub mold clamping mechanism into and out of the main mold clamping mechanism, and vertically in the die set. An alternating injection molding machine consisting of two sets of dies which are divided and attached is described in Japanese Patent Publication No. 63-67455.

The vertical type main mold clamping mechanism provided in this conventional one is provided with a mold clamping cylinder on an upper plate which is connected by a tie bar and is located above, and a movable plate which guides the tie bar by the mold clamping cylinder. It is configured to pressurize and clamp the die fed together with the die set between the movable platen and the lower platen.

[0004]

One of the problems in such a case is that the mold clamping force acts on the guide means and the moving means interposed between the lower die mounting plate and the lower board of the die set, and the mold clamping force is prolonged. In use, the guide means and the moving means are easily damaged by the mold clamping force repeatedly received.

Further, since the mold clamping cylinder having a load is located above, there is a problem in the stability of the molding machine. Further, the injection device is laterally arranged on the side of the vertical main mold clamping mechanism. Due to this, the ejection force acts at a right angle to the clamping force in the vertical direction, so a larger clamping force is required than when the ejection force is opposed to the clamping force, and as a result, it is adopted there. The main mold clamping mechanism of 1 also has a problem that it tends to be large.

The present invention was conceived in order to solve the above-mentioned conventional problems, and its purpose is to lower the mold clamping direction of the main mold clamping mechanism from the lower side to the upper side and vice versa. The main mold clamping mechanism is configured so that the influence of the mold clamping force on the guide means and the moving means can be reduced, and the stability and the simplification of the molding machine can be improved.

[0007]

According to the features of the present invention according to the above object, an upper pressure receiving plate above the machine base and a lower pressure receiving plate inside the machine base are integrally connected by a tie bar fixed to the machine base, and the lower portion thereof is connected. A main mold clamping mechanism is configured by providing a mold clamping ram on the pressure receiving plate.
The upper pressure receiving plate is provided with the injection device facing downward.

[0008]

[Operation] In the above configuration, the pressure from the mold clamping ram is transmitted to the lower mold mounting plate of the sub mold clamping mechanism that is in contact with the mold clamping ram due to the rise, whereby the sub mold clamping mechanism ascends together with the mold,
The upper die mounting plate contacts the upper pressure receiving plate of the main die clamping mechanism, and strong die clamping of the die occurs there. In addition, since the injection pressure acts vertically from above with respect to the upward mold clamping force, the mold clamping force can be smaller than when the ejection force acts at right angles to the vertical mold clamping force. It will be.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, 1A and 1B are a pair of sub-clamping mechanisms for each mold 11, and a plurality of hydraulic cylinders 13 for opening and closing are provided below a lower mold mounting plate 12 and are connected to pistons 14 of the plurality of cylinders. An upper die mounting plate 16 having a nozzle insertion hole at the center is joined to the upper end of the tie bar 15. Also, the upper die mounting plate 16
From the lower die mounting plate 12, a plurality of guide shafts 17
(See FIG. 2) is inserted, and the guide shaft 17 causes the upper die mounting plate 16 to vertically open and close by the hydraulic cylinder 13.

In the lower center of the lower die mounting plate 12, a die clamping ram contact portion 1 which also serves as a hydraulic cylinder of the ejector 18 is formed.
9 is projectingly provided, and a positioning hole 20 (see FIG. 2) is provided at a required position of the upper die mounting plate 16.

Reference numeral 2 denotes a machine base which is long in the lateral direction, and which is an upper base plate 21.
The pair of auxiliary mold clamping mechanisms 1A and 1B are mounted on the upper side of the lower mold mounting plate 12 so as to be movable laterally by fitting the stepped portions formed on the outer sides of the lower mold mounting plate 12 to the guide members 21a and 21a on both sides. I am doing it. A vertical main mold clamping mechanism 3 is provided at the center of the machine base 2, that is, at the center of the machine base where both the auxiliary mold clamping mechanisms 1A and 1B are stopped.
Is provided.

Inside the base plate 21 on one side of the machine base 2,
Driving means for moving the sub mold clamping mechanisms 1A and 1B at the same time to alternately move the sub mold clamping mechanisms 1A and 1B into and out of the main mold clamping mechanism 3 is installed in the longitudinal direction. A hydraulic device, a link mechanism, or the like can be adopted as this drive means, but in this embodiment, as shown in FIG. 3, an electric motor 22 such as a servomotor is used as a drive source, and the rotational force thereof is used for the ball screw shaft 2.
3 and the ball screw shaft 23 and the guide case 24
The lower die mounting plate 12 of both the sub die clamping mechanisms 1A and 1B is partially movable on both ends of the feed piece member 25 so as to be vertically movable. Fitted and connected.

The main mold clamping mechanism 3 has an upper pressure receiving plate 30 horizontally positioned above the machine base 2 and a lower pressure receiving plate 31 horizontally positioned inside the machine base 2 on a base plate 21 of the machine base 2. A plurality of tie bars 32, 32, which are inserted and fixed, are integrally coupled to each other, and a mold clamping cylinder having a mold clamping ram 33 is provided in the central portion of the lower pressure receiving plate 31 thereof.

Further, the upper pressure receiving plate 30 is provided with a hydraulically operated positioning device 35 having a positioning pin 34 which fits into the positioning hole 20 of the upper mold mounting plate 16 of the sub-mold clamping mechanism 1A, 1B. At the center upper part, the injection device 4 is mounted on the pistons 37, 37 of the pair of lifting cylinders 36, 36 and the support plate 3
8 are connected and provided so as to be vertically movable so as to face downward.

In the injection molding machine having such a structure, the lower mold mounting plate 12 and the upper mold mounting plate 1 of each sub-mold clamping mechanism 1A, 1B are mounted.
6, the mold 11 is divided and attached, and one of the molds 11 is sent into the main mold clamping mechanism 3 together with the sub mold clamping mechanism 1B by the driving means, and the sub mold clamping mechanism 33 is driven by the mold clamping ram 33. After the mold 11 is clamped together with 1B, the injection device 4 is lowered and the nozzle is touched, so that the resin can be injected into the mold 11.

The pressure generated by the mold clamping ram 33 is first transmitted to the lower mold mounting plate 12 via the mold clamping ram abutment portion 19 which is in contact with the mold clamping ram 33 due to the rise, whereby the mold 1
4, the sub mold clamping mechanism 1B rises as shown in FIG. 4, and the upper mold mounting plate 16 moves the upper mold pressure plate 30 of the main mold clamping mechanism 3.
And the mold is strongly clamped there. Further, in this case, since the injection pressure acts perpendicularly on the upward mold clamping force, the mold clamping force exerts the ejection force at a right angle to the vertical mold clamping force. It will be smaller than the case.

When the gate seal after injection is completed,
When the injection device 4 is pulled up and the upper mold mounting plate 16 is maintained in the mold clamping state by the hydraulic cylinder 13 of the sub mold clamping mechanism 1B, the mold clamping ram 33 is returned to its original position to remove the mold clamping force. Since the mechanism 1B can move on the base plate 21, when the electric motor 22 is rotated in the reverse direction, the feed piece member 25 moves so that the sub mold clamping mechanism 1B goes out of the main mold clamping mechanism 3 and instead the adjacent mold clamping mechanism 3 moves. The sub mold clamping mechanism 1A is fed into the main mold clamping mechanism 3.

Then, after the mold is clamped in the same manner as described above, injection molding is carried out by the injection device 4, and in the sub-mold clamping mechanism 1B, the mold clamping state is maintained until the resin in the mold is cooled and solidified, and thereafter. The mold is opened by the hydraulic cylinder 13 and the molded product is taken out. After the molded product is taken out, the sub mold clamping mechanism 1B is clamped again for the next injection molding.

Although the above steps are for ordinary injection molding, injection compression molding can also be performed. In this case, first, the gap between the upper pressure receiving plate 30 and the upper die mounting plate 16 is adjusted so as to serve as a compression allowance, and after being sent to the main die clamping mechanism 3, the upper die attaching plate 16 is moved by the hydraulic cylinder 13. The mold is opened until it hits the upper pressure receiving plate 30 to expand the cavity volume in the mold. In this state, after the resin is injected and filled from the injection device 4 into the mold, the mold opening by the hydraulic cylinder 13 is used as the mold clamping. At the same time as switching, the mold clamping force of the main mold clamping mechanism 3 is increased to reduce the cavity volume and compress the resin in the cavity.

It is desirable that this compressive force be gradually reduced in accordance with the degree of cooling of the resin. As means for this, the hydraulic cylinder 13 and the cylinder of the mold clamping ram 33 are sequentially released or the main pressure is released. It is possible to employ a method in which the mold clamping force is controlled by the hydraulic cylinder 13 after being fed from the mold clamping mechanism 3.

In the above embodiment, the positioning hole 20 and the positioning pin 34 are used to position the main mold clamping mechanism and the sub mold clamping mechanism at the time of injection molding. Since positioning can be performed by providing a stopper or controlling the movement position, the present invention is not limited to the positioning described in the embodiment.

[0022]

As described above, according to the present invention, the upper pressure receiving plate 30 above the machine base 2 and the lower pressure receiving plate 31 inside the machine base 2 are
The tie bar 32 fixed to the machine base 2 is integrally connected, and the lower pressure receiving plate 31 is provided with the mold clamping ram 33 to configure the main mold clamping mechanism 3 in the alternating injection molding machine, and the upper pressure receiving plate 30 is provided with the injection device 4. Is provided in the downward direction, the following effects are obtained.

Since the sub mold clamping mechanism is pressed against the upper pressure receiving plate fixed above the machine base by the mold clamping ram of the lower pressure receiving plate to perform strong mold clamping of the mold, the mold clamping force is the same as that of the sub mold clamping mechanism. It does not act on the moving means, the guide member, etc. Therefore, it is not necessary to make the moving means, the guide member, etc. particularly robust, unlike the conventional alternating injection molding machines.

Since the mold clamping force is applied upward with respect to the downward ejection force, the mold clamping force is smaller than that when the ejection force acts at right angles to the mold clamping direction. Therefore, the main mold clamping mechanism can be downsized, and the rigidity can be reduced to simplify the structure.

-The mold clamping ram having a load is placed on the lower side,
Since the upper pressure receiving plate is equipped with an injection device that is lighter than the mold clamping ram, etc., the stability of the molding machine is improved compared to the conventional one, and the tie bar etc. can be rigid enough to withstand those loads, so there is also a mounting space. The molding machine can be compactly integrated and downsized as a whole without requiring a wide space, and the installation area of the molding machine can be small because the injection device is vertically accommodated in the machine base.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional front view of an alternating injection molding machine according to the present invention.

FIG. 2 is a schematic vertical sectional side view of the main mold clamping mechanism.

FIG. 3 is a schematic vertical sectional front view of a drive means portion of the sub mold clamping mechanism.

FIG. 4 is a schematic vertical cross-sectional front view of a portion of a driving unit showing a mold clamping state of a mold by a mold clamping ram.

[Explanation of symbols]

 1A, 1B Sub mold clamping mechanism 2 Machine base 3 Main mold clamping mechanism 4 Injection device 11 Mold 12 Lower mold mounting plate 13 Hydraulic cylinder 15 Tie bar 16 Upper mold mounting plate 19 Mold clamping ram abutment member 21 Base plate 21a Guide member 22 Electric motor 23 Ball screw shaft 24 Guide case 25 Feeding piece member 30 Upper pressure receiving plate 31 Lower pressure receiving plate 32 Tie bar 33 Mold clamping ram

Claims (1)

[Claims] 1. A pair of sub mold clamping mechanisms provided with mold opening / closing means at the top and bottom, a machine stand on which the sub mold clamping mechanisms are movably mounted in the lateral direction, and both of the sub mold clamping mechanisms are at stop positions. A vertical main mold clamping mechanism arranged in the center of the machine base and drive means on the machine side for moving the sub mold clamping devices at the same time to alternately move the sub mold clamping mechanism in and out of the main mold clamping mechanism. , Consists of two sets of dies attached to each sub-clamping mechanism divided into upper and lower parts, and the main mold-clamping mechanism has an upper pressure receiving plate above the machine base and a lower pressure receiving plate inside the machine base. An alternating injection molding machine characterized in that it is integrally connected by a tie bar fixed to the lower pressure receiving plate, a mold clamping ram is provided on its lower pressure receiving plate, and an injection device is provided downward on the upper pressure receiving plate.