JPH09207183A - Mold clamping apparatus for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts and to enable the miniaturization of an apparatus as a whole including the curtailment of total length of the apparatus. SOLUTION: The mold clamping ram 4 of a mold clamping cylinder 2 is whirl-stopped by a guide mechanism 14 which guides transfer in the axial direction to be installed, a movable mold 8 which is mold-clamped to a fixed mold 7 held by a fixed die plate 5 is held by the ram 4, and mold closing, mold clamping, and mold opening can be made directly by the cylinder 2 without using a movable die plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device, and more particularly to a mold clamping device for injection molding, which has a small moving stroke of a mold clamping ram and is applied to optical disc molding such as compact disc and digital video disc.

[0002]

2. Description of the Related Art In this type of injection molding machine, a movable die plate for holding a movable die is advanced with respect to a fixed die plate for holding a fixed die, and after closing and clamping the die, a nozzle is attached to the die. Molten resin is injected into the mold from the nozzle by touching to mold, and then the injection side is retracted and the mold clamping side is opened to take out the molded product. During optical disc molding, a stamper is held on a fixed mold and / or a movable mold.

In the mold clamping device at this time, the mold clamping cylinder and the fixed die plate are connected via a tie bar, and the mold clamping cylinder applies tension to the tie bar to perform the mold clamping. In addition, it is configured to have a moving die plate and a mold opening / closing cylinder as a moving means of the moving die plate.

[0004]

However, the conventional mold clamping device for an injection molding machine requires a mold opening / closing cylinder attached to the moving die plate due to the presence of the moving die plate, which increases the number of parts and increases the size of the entire device. There is a problem of inducing

Further, in the conventional mold clamping device, in order to secure the moving space of the moving die plate, it is not possible to sufficiently reduce the total length although the moving stroke of the moving die (moving die plate) is small. It also has challenges.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to make it possible to reduce the number of parts and to reduce the size of the entire apparatus including the shortening of the overall length of the apparatus. An object is to provide a mold clamping device for injection molding.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that a mold clamping cylinder and a fixed die plate are connected to each other through a tie bar, and the mold clamping cylinder is connected to the tie bar. In a mold clamping device for injection molding that applies tension to mold clamping, the mold clamping ram of the mold clamping cylinder is attached to the stationary die plate while being stopped by a guide mechanism that guides axial movement. It is characterized in that a movable mold, which is clamped to the fixed mold, is held by the mold clamping ram.

Therefore, according to the first aspect of the invention, the movable mold is held by the mold clamping ram, and the mold clamping ram is prevented from rotating by the guide mechanism and is moved back and forth while maintaining parallelism with the fixed die plate. To do. Therefore, the mold closing, the mold clamping and the mold opening are directly performed by the mold clamping cylinder without using the moving die plate.

The invention according to claim 2 is the mold clamping apparatus for injection molding according to claim 1, in which the guide mechanism comprises:
A guide pin axially protruding from the rear of the mold clamping cylinder, and a guide hole fixed to the end of the mold clamping ram protruding outward from the mold clamping cylinder and slidably inserted into the guide pin. It is characterized in that it is composed of a guide plate having a hole.

Therefore, in the invention according to claim 2, the mold clamping ram moves forward and backward together with the guide plate in which the guide hole is inserted in the guide pin, and the rotation is prevented and the parallelism is maintained through the guide plate. .

Further, the invention according to claim 3 is the mold clamping apparatus for injection molding according to claim 1 or 2, wherein a bush for guiding the sliding of the mold clamping ram is mounted in the mold clamping cylinder. Is characterized by.

Therefore, according to the third aspect of the invention, the parallelism of the mold clamping ram is maintained with high accuracy by the bush mounted in the mold clamping cylinder.

[0013]

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

1 to 4 show a mold clamping device 1 as an embodiment of the present invention. In this mold clamping device 1, a mold clamping cylinder 2 and a fixed die plate 5 are connected via a tie bar 6, and the mold clamping cylinder 2 applies tension to the tie bar 6 to perform mold clamping. The mold clamping ram 4 of the cylinder 2 is fixed by a guide mechanism 14 that guides the axial movement so as not to rotate, and the movable mold 8 is clamped to the fixed mold 7 held by the fixed die plate 5. It is held by the ram 4 and is generally configured.

The mold clamping cylinder 2 is composed of a cylinder block 3 whose lower part is fixed to a frame 12, and a mold clamping ram 4 which is slidably mounted through the cylinder block 3 so as to be parallel to the frame 12. It is configured. The mold clamping ram 4 includes a piston portion 41 formed in a large diameter in a substantially central portion,
The piston portion 41 is formed with a front rod portion 42 and a rear rod portion 43 each having a small diameter on both sides,
A seal member 10 is interposed between the front and rear rod portions 42 and 43 and the cylinder block 3 so as to be slidable in the axial direction. By mounting the mold clamping ram 4, a front pressure chamber 31 and a rear pressure chamber 32 are formed on both sides of the piston portion 41 in the cylinder block 3.

Preferably, as shown in FIG. 1, the bush 9 for guiding the slide of the mold clamping ram 4 is attached to the cylinder block 3.
It can be provided in. In this embodiment, two bushes 9 are provided so as to guide the front and rear rod parts 42 and 43, and the mold clamping ram 4 is provided with these two bushes 9, 9.
It is supported at two points and can slide with a high degree of parallelism.

The guide mechanism 14 includes a guide pin 15 axially protruding from the rear portion of the cylinder block 3 and a mold clamping ram 4.
Guide hole 1 fixed to the end protruding from the cylinder block 3 to the rear outward and slidably inserted in the guide pin 15.
The guide plate 16 is provided with 6a.

Four guide pins 15 are provided at equal intervals along the circumferential direction of the rear end surface of the cylinder block 3 (see FIG. 4). The number of guide pins 15 installed on the diagonal line is 2 within a range that does not hinder the anti-rotation function of the mold clamping ram 4.
It is possible to reduce the number to 4 or less by providing one or the like.

The guide plate 16 is made of a disk member, and a guide hole 16a is formed in the outer peripheral portion thereof so as to match the installation interval of the guide pins 15. This guide plate 16
The guide hole 16a is externally inserted into the guide pin 15, and the inner peripheral side portion thereof is fixed to the rear end surface of the rear rod portion 43 of the mold clamping ram 4 protruding outward from the rear portion of the cylinder block 3 with a screw 19. It is attached (see Figure 4). Furthermore, a bush for guiding the sliding of the guide pin 15 can be provided in the guide hole 16a.

The fixed die plate 5 is connected to the cylinder block 3 fixed on the frame 12 via four tie bars 6, and the lower part of the fixed die plate 5 is provided on the frame 12 in parallel linear guides 13, 13. (See FIG. 3), the mold is opened and closed so that it can move in the mold opening and closing direction. When the mold is clamped, the tie bar 6 is allowed to move and is fixed so that the tie bar 6 can move in the injection direction. At this time, one end 6a of the tie bar 6 is fitted into the fixed die plate 5 and connected by the nut 17, and the other end 6b is connected to the tie bar locking means 1.
It is connected to the cylinder block 3 by 8 (see FIGS. 2 and 3).

Further, a cylinder rod 20 of a nozzle touch cylinder (not shown) on the injection side is connected to the fixed die plate 5 (see FIG. 3).

As shown in FIG. 4, the tie bar locking means 18 are provided at the four corners of the cylinder block 3 corresponding to each of the four tie bars 6, and a ring member rotatably provided on the cylinder block 3. 22 and the bracket 23 of the ring member 22 with the one end side through the cylinder rod 21.
And a cylinder 20 connected to a bracket 24 projecting laterally from the cylinder block 3 at the other end. As shown in FIG. 5, the ring member 22 has a plurality of inwardly-opening recesses 22a provided at equal intervals along the inner circumference and a threaded portion 22b engraved along the inner circumference.
And is configured.

On the other hand, on the other end 6b of the tie bar 6, projections 6c corresponding to the recesses 22a of the ring member 22 are formed at equal intervals along the outer circumference, and the projections 6c should be inserted corresponding to the recesses 22a. The other end 6b of the tie bar 6 can be inserted into the ring member 22 (see FIG. 5A) by rotating the ring member 22 in the a direction by the cylinder 20 in this state so that the projection 6c is screwed. 22b
The movement of the tie bar 6 in the axial direction is locked by being screwed in (see FIG. 5B), and the other end 6b can be connected to the cylinder block 3. Further, in order to release this locked state, the ring member 22 is moved by the cylinder 20 as shown in FIG.
This can be carried out by rotating the tie bar 6 in the b direction of (b) so that the concave portion 22a and the projection 6c are aligned with each other, whereby the axial movement of the tie bar 6 becomes possible.

The movable die 8 clamped to the fixed die 7 held by the fixed die plate 5 is directly held on the front end surface of the front rod portion 42 of the die clamping ram 4 as shown in FIG. . Reference numeral 11 in the drawing is a stopper of the seal member 10 fitted in the front and rear openings of the cylinder block 3, and reference numeral 21 is a nozzle insertion hole of an injection side nozzle (not shown).

The mold clamping device 1 assembled as described above operates as follows.

In normal operation during injection molding, the tie bar lock means 18 is kept in the locked state, and the front and rear pressure chambers 31,
This can be done by alternately supplying hydraulic pressure to 32.

That is, by supplying pressure oil to the rear pressure chamber 32, the mold clamping ram 4 advances, mold closing and mold clamping are performed, and the injection side nozzle inserted into the nozzle insertion hole 21 in this mold clamping state. Injection molding is performed by injecting a molten resin into the cavity between the two molds 7, 8. After injection molding, by supplying pressure oil to the front pressure chamber 31, the mold clamping ram 4 is retracted, the mold is opened, and the molded product is taken out in this mold opened state.

In this way, the normal operation is performed by repeating the forward / backward movement of the mold clamping ram 4 with respect to the fixed die plate 5. The mold clamping ram 4 during the normal operation moves back and forth with a moving stroke S ₁ as shown in FIG.

The mold clamping ram 4 during normal operation moves forward and backward together with the guide plate 16 in which the guide hole 16a is inserted in the guide pin 15, and the rotation of the mold can be prevented through the guide plate 16 and the mold clamping cylinder. The parallelism with the bushes 9 and 9 mounted in 2 is maintained with high precision.

When maintenance work is required, it is carried out as follows.

That is, when the mold opening is completed by retreating the mold clamping ram 4 and the injection side reaches the retreat limit, the tie bar locking means 18 is made lock-free. As a result, the connection between the other end 6b of the tie bar 6 and the cylinder block 3 is released.

In this state, when the nozzle touch cylinder (not shown) on the injection side is driven to retract the cylinder rod 20, the fixed die plate 5 is guided by the linear guide 13 and moves toward the injection side, A gap required for maintenance work can be secured between the tightening cylinder 2.

After the maintenance work is completed, when the nozzle touch cylinder is driven to advance the cylinder rod 20, the fixed die plate 5 is guided by the linear guide 13 to return to the molding position during the normal operation, and in this state. By locking the tie bar locking means 18, the other end 6b of the tie bar 6 and the cylinder block 3 can be connected and a normal operation posture can be taken. During the maintenance, the fixed die plate 5 has a stroke S _{2 as} shown in FIG.
To reciprocate.

As described above, in the mold clamping device 1, the movement stroke S ₁ (mold opening / closing stroke) of the mold clamping ram 4 is small, but a sufficient gap is secured during maintenance to facilitate the maintenance work. You can do it.

In this mold clamping apparatus 1, the mold closing, mold clamping and mold opening are performed directly by the mold clamping cylinder 2 without the intermediary of the movable die plate. Therefore, the movable die plate and the mold opening / closing cylinder conventionally required. Not only is it unnecessary, but it is not necessary to secure a moving space for the moving die plate within the entire length of the device, and as a result, it is possible to reduce the number of parts and to downsize the entire device including shortening the overall length of the device. Can also be achieved.

[0036]

As described above in detail, the present invention has the following effects.

That is, according to the first aspect of the present invention,
Since the mold closing, mold clamping and mold opening are performed directly by the mold clamping cylinder without passing through the moving die plate, not only the moving die plate and the mold opening / closing cylinder become unnecessary, but also the moving space of the moving die plate within the entire length of the apparatus. Since it is not necessary to incorporate the device, it is possible to reduce the number of parts, and it is also possible to reduce the size of the entire device including shortening the overall length of the device.

According to the second aspect of the invention, the mold clamping ram moves forward and backward together with the guide plate in which the guide hole is inserted in the guide pin to prevent rotation and maintain parallelism through the guide plate. Therefore, the molding precision in precision injection molding is maintained.

Further, according to the third aspect of the invention, since the parallelism of the mold clamping ram is maintained with high precision by the bush mounted in the mold clamping cylinder, the molding precision in precision injection molding is maintained.

[Brief description of drawings]

FIG. 1 is a side view showing a partial cross section of a mold clamping device for injection molding according to an embodiment.

FIG. 2 is a partial cross-sectional plan view of the mold clamping device for injection molding of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a view on arrow Z in FIG.

5A and 5B are operation explanatory views of the tie bar locking means used in the injection molding mold clamping device of FIG. 1, in which FIG. 5A shows a released state and FIG. 5B shows a locked state.

[Explanation of symbols]

 1 Molding device for injection molding 2 Molding cylinder 4 Molding ram 5 Fixed die plate 6 Tie bar 7 Fixed mold 8 Moving mold 9 Bushing 14 Guide mechanism 15 Guide pin 16 Guide plate 16a Guide hole

Claims (3)

[Claims] 1. A mold clamping apparatus for injection molding, wherein a mold clamping cylinder and a fixed die plate are connected via a tie bar, and tension is applied to the tie bar by the mold clamping cylinder to perform mold clamping. The mold clamping ram of the clamping cylinder is fixed by a guide mechanism that guides the movement in the axial direction, and is mounted so that the movable mold that is clamped to the fixed mold held by the fixed die plate is fixed to the mold clamping ram. A mold clamping device for injection molding, which is held. 2. The mold clamping device for injection molding according to claim 1, wherein the guide mechanism includes a guide pin axially protruding from a rear portion of the mold clamping cylinder, and the mold clamping cylinder of the mold clamping ram. A mold clamping device for injection molding, comprising: a guide plate that is fixed to an end portion that projects outward from the guide plate and that has a guide hole that is slidably inserted into the guide pin. 3. The mold clamping device for injection molding according to claim 1 or 2, wherein a bush for guiding the sliding of the mold clamping ram is mounted in the mold clamping cylinder. Mold clamping device.