JP2001212857A - Mold clamping apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly generate mold clamping force while enhancing the accuracy of a molded article. SOLUTION: A mold clamping apparatus has a base 11, a fixed platen 12 arranged to the base 11 in a freely movable manner, the base plate arranged to the base 11 in a freely movable manner, the tie 13 provided across the fixed platen 12 and the base plate, the movable platen arranged so as to freely advance and retreat along the tie bars 13, a mold clamping means and an attaching means 30 for attaching the fixed platen 12 to the base 11 and permitting the lower end of the fixed platen 12 to move toward the base plate at a time of mold clamping. The fixed platen 12 is moved toward the base plate at the lower and upper ends thereof by the tie bars 13.

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.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin heated and melted in a heating cylinder of an injection device is filled in a cavity space of a mold device, and the resin in the cavity space is filled. The molded article is formed by cooling and solidifying.

For this purpose, the mold apparatus comprises a fixed mold and a movable mold. The movable mold is moved forward and backward, and is brought into and out of contact with the fixed mold to close, close, and close the mold. It can be opened.

FIG. 2 is a diagram showing a state of attachment of a conventional fixed platen, and FIG. 3 is a diagram showing a state of a conventional fixed platen at the time of mold clamping.

In the drawing, reference numeral 11 denotes a base, 12 denotes a fixed platen attached to the base 11 by bolts b1 and b2, and 13 denotes four bridges (in FIG. 1) provided between the fixed platen 12 and a base plate (not shown). Only two of them are shown.) A movable platen (not shown) is provided along the tie bar 13 so as to be able to advance and retreat. Then, the fixed mold 16 and the movable mold 1 are respectively attached to the fixed platen 12 and the movable platen.
7 are mounted facing each other. In addition, a mold device is constituted by the fixed mold 16 and the movable mold 17. Further, the base plate is not fixed to the base 11 but is movably disposed with respect to the base 11.

A mold clamping cylinder (not shown) is provided between the base plate and the movable platen, and the movable platen advances and retreats along the tie bar 13 by driving the mold clamping cylinder. The base 11, the fixed platen 12, the tie bar 13, the fixed mold 16, the movable mold 17, the base plate, the movable platen, and the mold cylinder constitute a mold clamping device.

When the movable platen and the movable mold 17 are advanced (moved to the right in FIGS. 2 and 3) and the mold is closed, not shown between the fixed mold 16 and the movable mold 17. A cavity space is formed. Subsequently, a mold clamping force is generated by the mold clamping cylinder, the mold is clamped, and the fixed mold 16 and the movable mold 17 are pressed by the mold clamping force. At this time, a resin injected by an injection device (not shown) is filled in the cavity space, and the resin in the cavity space is cooled and solidified to form a molded product.

Subsequently, the movable platen and the movable mold 1
7 is retracted (moved to the left in FIGS. 2 and 3),
The mold is opened. At this time, an ejector pin (not shown) is protruded from the movable mold 17 and the molded product attached to the movable mold 17 is pushed down.

[0009]

However, in the above-mentioned conventional mold clamping device, the mold clamping force cannot be generated uniformly. That is, the mold clamping cylinder is
In order to press the fixed mold 16 and the movable mold 17, a force is generated to pull the fixed platen 12 toward the base plate via the tie bar 13. At this time, as shown in FIG. 3, since the lower end of the fixed platen 12 is fixed to the base 11, it is not moved by the tie bar 13, and the upper end of the fixed platen 12 is moved to the base plate side by the tie bar 13. Therefore, the fixed platen 12 is not deformed at the lower end, but is deformed toward the movable platen as the distance from the lower end is increased. Therefore, the amount of deformation differs between the upper part and the lower part of the center of the fixed platen 12. In addition, the extension amount differs between the upper tie bar 13 and the lower tie bar 13.

[0010] As a result, the mold clamping force cannot be generated uniformly, and the precision of the molded product decreases.

The present invention solves the above-mentioned problems of the conventional mold clamping device, and provides a mold clamping device capable of uniformly generating a mold clamping force and increasing the precision of a molded product. With the goal.

[0012]

For this purpose, in the mold clamping apparatus of the present invention, a base, a fixed platen movably disposed with respect to the base and having a fixed mold attached thereto, and A base plate movably disposed with respect to the tie bar, a tie bar provided between the fixed platen and the base plate, a movable platen movably disposed along the tie bar, and having a movable mold attached thereto;
Mold clamping means for pressing the movable mold and the fixed mold to clamp the mold, and attaching means for attaching the fixed platen to a base and allowing the lower end of the fixed platen to move toward the base plate during mold clamping. And

In another embodiment of the present invention, the mounting means is a mechanical shock absorbing means.

In still another mold clamping device according to the present invention, the mounting means is a hydraulic shock absorbing means.

In still another mold clamping apparatus according to the present invention, the attaching means further includes a return means for returning the lower end of the fixed platen to a return position when the mold is closed and the mold is opened.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic view of a main part of a mold clamping device according to a first embodiment of the present invention, FIG. 4 is a schematic diagram of a mold clamping device according to the first embodiment of the present invention, and FIG. FIG. 6 is a right side view of a main part of the mold clamping device according to the first embodiment of the present invention, FIG. 6 is a diagram showing a state of the mold clamping device at the time of mold clamping according to the first embodiment of the present invention, and FIG. FIG. 4 is a diagram illustrating a state of the fixed platen at the time of mold clamping according to the first embodiment.

In the drawing, reference numeral 11 denotes a base, 12 denotes a fixed platen movably disposed with respect to the base 11, 1
Reference numeral 4 denotes a base plate movably disposed with respect to the base 11. Four tie bars 13 are provided between the fixed platen 12 and the base plate 14, and a movable platen 15 is provided along the tie bars 13 so as to be able to advance and retreat (move in the left and right directions in FIGS. 4 and 6). A fixed mold 16 and a movable mold 17 are attached to the fixed platen 12 and the movable platen 15 so as to face each other. In addition, a mold device is constituted by the fixed mold 16 and the movable mold 17.

The base plate 14 and the movable platen 1
5, a mold clamping cylinder 21 is disposed as mold clamping means for pressing the fixed mold 16 and the movable mold 17 to clamp the mold, and by driving the mold clamping cylinder 21,
The movable platen 15 is moved forward and backward along the tie bar 13. One end of the mold clamping cylinder 21 has the base plate 1.
4, a cylinder body 22, and a rod 23 slidably mounted on the cylinder body 22, one end of which is attached to the movable platen 15, and an oil chamber in the cylinder body 22. , The mold clamping cylinder 21 can be driven. The base 11 and the fixed platen 1
2, tie bar 13, base plate 14, movable platen 15, fixed mold 16, movable mold 17, and clamping cylinder 2
1 forms a mold clamping device.

When the movable platen 15 and the movable mold 17 are advanced (moved to the right in FIGS. 4 and 6) and the mold is closed, the fixed mold 16 and the movable mold 17 are moved.
, A cavity space (not shown) is formed. Subsequently, a mold clamping force is generated by the mold clamping cylinder 21, the mold is clamped, and the fixed mold 16 and the movable mold 17 are pressed by the mold clamping force. At this time, a resin injected by an injection device (not shown) is filled in the cavity space, and the resin in the cavity space is cooled and solidified to form a molded product.

Subsequently, the movable platen 15 and the movable mold 17 are retracted (moved to the left in FIGS. 4 and 6), and the mold is opened. At this time, an ejector pin (not shown) protrudes from the movable mold 17 and the movable mold 1
The molded product adhering to 7 is pushed down. Note that, instead of the mold clamping cylinder 21, a toggle mechanism, a hydraulic motor,
An actuator such as a motor can also be used.

By the way, the mold clamping cylinder 21
Generates a force to pull the fixed platen 12 toward the base plate 14 via the tie bar 13 in order to press the fixed mold 16 and the movable mold 17. At this time,
If the fixed platen 12 is fixed to the base 11, the lower end of the fixed platen 12 is not moved by the tie bar 13, and the upper end of the fixed platen 12 is
Is moved to the base plate 14 side. In this case, the fixed platen 12 is not deformed at the lower end, but is deformed toward the movable platen 15 as the distance from the lower end is increased. In addition, the upper tie bar 13
And the lower tie bar 13 have different elongation amounts.

Therefore, the fixed platen 12 is disposed movably with respect to the base 11, and
And is attached to the base 11 via. The mounting means 3
Reference numeral 0 denotes a cylindrical fixing block 31 as a fixing member attached to the base 11 by bolts (not shown), a bolt 33 as a connecting member attached to the lower end of the fixed platen 12 and having a head 32 at the tip, and A spring 34 is provided between the fixed block 31 and the bolt 33 and serves as an urging member for urging the fixed platen 12 toward the fixed block 31 with a predetermined urging force. . The bolt 33 and the spring 34
When closing the mold, the lower end of the fixed platen 12 is
5 to move to the side, when closing the mold and opening the mold,
The lower end of the fixed platen 12 is returned to the return position where it comes into contact with the fixed block 31 by the urging force. Therefore, the spring constant of the spring 34 is determined by the mold closing operation and the mold opening operation of the mold clamping device, and the injection operation of the injection device.
The value is set so that the fixed platen 12 does not separate from the fixed block 31. The bolt 33 and the spring 34
The return means is constituted by.

As described above, since the fixed platen 12 is provided so as to be movable with respect to the base 11, when the mold is clamped,
The lower and upper ends are moved toward the base plate 14 by the tie bars 13. Therefore,
The fixed platen 12 is deformed toward the movable platen 15 as it moves away from the center, and the amount of deformation is equal above and below the center of the fixed platen 12. Further, the elongation amounts of the upper tie bar 13 and the lower tie bar 13 are equal.

As a result, the mold clamping force can be generated uniformly, and the precision of the molded product can be increased.

Next, a second embodiment of the present invention will be described.

FIG. 8 is a schematic view of a main part of a mold clamping device according to a second embodiment of the present invention.

In this case, the fixed platen 12 is
1, and is attached to the base 11 via the attaching means 40. The mounting means 40
Is a cylinder body 4 of a hydraulic cylinder as a fixing member attached to the base 11 by bolts (not shown).
1, and a rod 43, which is attached to the lower end of the fixed platen 12 and has a piston 42 at its tip, as a connecting member, constitutes a hydraulic shock absorbing means. Further, the inside of the cylinder body 41 is partitioned by the piston 42, and a header-side oil chamber 44 as a first oil chamber and a rod-side oil chamber 45 as a second oil chamber are formed. And
A hydraulic pressure is selectively supplied to the rod-side oil chamber 45 from a hydraulic supply / discharge unit of a hydraulic circuit (not shown), for example, a switching valve via a pressure adjusting valve. In addition, 13 is a tie bar, 16 is a fixed mold, and 17 is a movable mold.

The switching valve supplies a hydraulic pressure to the rod-side oil chamber 45 via a pressure regulating valve at the time of closing the mold, so that the lower end of the fixed platen 12 moves toward the movable platen 15 (FIG. 4) with a predetermined buffering force. With the hydraulic pressure set beforehand when closing and opening the mold.
The lower end of the fixed platen 12 is returned to the return position where it comes into contact with the cylinder body 41. In this case, return means is constituted by the piston 42 and the rod-side oil chamber 45.

[0030] In the hydraulic circuit, an accumulator can be provided in place of the switching valve, the pressure regulating valve, and the like.

The present invention is not limited to the above embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0032]

As described above in detail, according to the present invention, in a mold clamping device, a base, a fixed platen movably disposed with respect to the base, and having a fixed mold attached thereto. A base plate movably disposed with respect to the base, a tie bar erected between the fixed platen and the base plate, and a movable die mounted on the tie bar so as to advance and retreat along the tie bar. A movable platen, a mold clamping unit that presses the movable mold and the fixed mold to perform mold clamping, and attaches the fixed platen to the base, and moves the lower end of the fixed platen to the base plate side during mold clamping. Mounting means to allow.

In this case, since the fixed platen is movably disposed with respect to the base, the fixed platen is moved toward the base plate by the tie bars at the lower end and the upper end when the mold is clamped. Therefore, the fixed platen deforms toward the movable platen as it moves away from the center, and
The amount of deformation is equal above and below the center of the fixed platen. In addition, the amount of elongation is equal between the upper tie bar and the lower tie bar.

As a result, the mold clamping force can be generated uniformly, and the precision of the molded product can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a mold clamping device according to a first embodiment of the present invention.

FIG. 2 is a view showing a state of attachment of a conventional fixed platen.

FIG. 3 is a view showing a state in which a conventional fixed platen is clamped.

FIG. 4 is a schematic view of a mold clamping device according to the first embodiment of the present invention.

FIG. 5 is a right side view of a main part of the mold clamping device according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a state at the time of mold clamping of the mold clamping device according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a state of the fixed platen according to the first embodiment of the present invention when the mold is clamped.

FIG. 8 is a schematic view of a main part of a mold clamping device according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 11 base 12 fixed platen 13 tie bar 14 base plate 15 movable platen 16 fixed mold 17 movable mold 21 mold clamping cylinder 30, 40 mounting means 31 fixed block 33 bolt 34 spring 41 hydraulic cylinder 42 piston 43 rod 45 rod side oil chamber

Claims (4)

[Claims] 1. A base, (b) a fixed platen which is movably disposed with respect to the base, and to which a fixed mold is attached, and (c) which is movably disposed with respect to the base. (D) a tie bar erected between the fixed platen and the base plate, (e) a movable platen which is disposed along the tie bar so as to be able to advance and retreat, and to which a movable mold is attached. f) mold clamping means for clamping the movable mold and the fixed mold by pressing the movable mold and the fixed mold; and (g) attaching the fixed platen to the base, and moving the lower end of the fixed platen toward the base plate during mold clamping. And a mounting means for permitting the clamping. 2. The mold clamping device according to claim 1, wherein said attaching means is a mechanical shock absorbing means. 3. The mold clamping device according to claim 1, wherein said attaching means is a hydraulic shock absorbing means. 4. The mold clamping apparatus according to claim 1, wherein said attaching means includes a return means for returning a lower end of said fixed platen to a return position when said mold is closed and said mold is opened.