JP4220643B2 - Clamping device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold clamping device.
[0002]
[Prior art]
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 cooled and solidified. As a result, a molded product is formed.
[0003]
For this purpose, the mold apparatus is composed of a fixed mold and a movable mold, and the mold is closed, clamped and opened by moving the movable mold forward and backward and bringing it into and out of contact with the fixed mold. Be able to.
[0004]
FIG. 2 is a view showing a conventional fixed platen attached state, and FIG. 3 is a view showing a state of the conventional fixed platen during mold clamping.
[0005]
In the figure, 11 is a base, 12 is a fixed platen attached to the base 11 with bolts b1 and b2, and 13 is a bridge between the fixed platen 12 and a base plate (not shown) (2 of them are shown in the figure). Only a book is shown), and a movable platen (not shown) is disposed along the tie bar 13 so as to freely advance and retract. A fixed mold 16 and a movable mold 17 are attached to the fixed platen 12 and the movable platen so as to face each other. The fixed mold 16 and the movable mold 17 constitute a mold apparatus. Further, the base plate is not fixed to the base 11 but is movably disposed with respect to the base 11.
[0006]
A mold clamping cylinder (not shown) is disposed between the base plate and the movable platen, and the movable platen is advanced and retracted 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 clamping cylinder constitute a mold clamping device.
[0007]
When the movable platen and the movable mold 17 are moved forward (moved to the right in FIGS. 2 and 3) and the mold is closed, a cavity space (not shown) is formed between the fixed mold 16 and the movable mold 17. It is formed. Subsequently, a mold clamping force is generated by the mold clamping cylinder, the mold clamping is performed, and the fixed mold 16 and the movable mold 17 are pressed with the mold clamping force. At this time, when the 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, a molded product is formed.
[0008]
Subsequently, the movable platen and the movable mold 17 are retracted (moved to the left in FIGS. 2 and 3), and the mold opening is performed. 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 dropped.
[0009]
[Problems to be solved by the invention]
However, in the conventional mold clamping device, the mold clamping force cannot be generated uniformly. That is, when the mold is clamped, the mold clamping cylinder generates a force to pull the fixed platen 12 toward the base plate via the tie bar 13 in order to press the fixed mold 16 and the movable mold 17. At this time, as shown in FIG. 3, the lower end of the fixed platen 12 is fixed to the base 11, so that 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. Accordingly, the fixed platen 12 is not deformed at the lower end, and is deformed to the movable platen side as it is separated from the lower end, so that the deformation amount is different between the upper side and the lower side of the fixed platen 12. Further, the amount of elongation 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 accuracy of the molded product is lowered.
[0011]
It is an object of the present invention to provide a mold clamping device that solves the problems of the conventional mold clamping device, can generate a mold clamping force uniformly, and can increase the accuracy of a molded product. To do.
[0012]
[Means for Solving the Problems]
For this purpose, in the mold clamping device of the present invention, the base, the fixed platen that is movably disposed with respect to the base, and to which the fixed mold is attached, are movably disposed with respect to the base. A base plate, a tie bar laid between the fixed platen and the base plate, a movable platen disposed so as to be movable forward and backward along the tie bar, and having a movable mold attached thereto; the movable mold and the fixed mold; And clamping means for clamping the mold, and mounting means for attaching the fixed platen to the base and allowing the lower end of the fixed platen to move toward the base plate during clamping.
The attaching means is disposed between the fixing member attached to the base and the fixing member and the fixed platen, and allows the movement of the lower end of the fixed platen when the mold is clamped. And a buffer means for returning the lower end of the fixed platen to the return position by an urging force when the mold is opened.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
FIG. 1 is a schematic view of a main part of a mold clamping device according to the first embodiment of the present invention, FIG. 4 is a schematic diagram of the mold clamping device according to the first embodiment of the present invention, and FIG. FIG. 6 is a diagram showing a state during mold clamping of the mold clamping device according to the first embodiment of the present invention, and FIG. 7 is a diagram illustrating the first embodiment of the present invention. It is a figure which shows the state at the time of the mold clamping of the stationary platen in embodiment.
[0018]
In the figure, 11 is a base, 12 is a stationary platen arranged to be movable with respect to the base 11, and 14 is a base plate arranged to be movable with respect to the base 11. Four tie bars 13 are installed between the fixed platen 12 and the base plate 14, and a movable platen 15 is disposed along the tie bar 13 so as to be movable back and forth (moved in the left-right direction 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. The fixed mold 16 and the movable mold 17 constitute a mold apparatus.
[0019]
Between the base plate 14 and the movable platen 15, a mold clamping cylinder 21 is disposed as mold clamping means for clamping the mold by pressing the fixed mold 16 and the movable mold 17, and drives the mold clamping cylinder 21. By doing so, the movable platen 15 is advanced and retracted along the tie bar 13. The mold clamping cylinder 21 is provided with a cylinder main body 22 having one end attached to the base plate 14 and a rod 23 having one end attached to the movable platen 15 and is slidably movable with respect to the cylinder main body 22. The mold clamping cylinder 21 can be driven by selectively supplying hydraulic pressure to the oil chamber in the cylinder body 22. The base 11, the fixed platen 12, the tie bar 13, the base plate 14, the movable platen 15, the fixed mold 16, the movable mold 17, and the mold clamping cylinder 21 constitute a mold clamping device.
[0020]
When the movable platen 15 and the movable mold 17 are moved forward (moved to the right in FIGS. 4 and 6) and the mold is closed, a cavity (not shown) is formed between the fixed mold 16 and the movable mold 17. A space 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 with the mold clamping force. At this time, when the 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, a molded product is formed.
[0021]
Subsequently, the movable platen 15 and the movable mold 17 are moved backward (moved to the left in FIGS. 4 and 6), and the mold opening is performed. 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 dropped. In place of the mold clamping cylinder 21, a toggle mechanism and an actuator such as a hydraulic motor or an electric motor can be used.
[0022]
By the way, at the time of mold clamping, 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 moved to the base plate 14 side by the tie bar 13. Become. In this case, the fixed platen 12 is not deformed at the lower end, and is deformed toward the movable platen 15 as it is separated from the lower end. Further, the amount of elongation differs between the upper tie bar 13 and the lower tie bar 13.
[0023]
Therefore, the fixed platen 12 is movably disposed with respect to the base 11 and is attached to the base 11 via the attachment means 30. The attachment means 30 is a cylindrical fixing block 31 as a fixing member attached to the base 11 by a bolt (not shown), a bolt as a connecting member attached to the lower end of the fixing platen 12 and having a head 32 at the tip. 33, and a spring 34 as a biasing member disposed between the fixed block 31 and the bolt 33 and biasing the fixed platen 12 toward the fixed block 31 with a predetermined biasing force. Configure. The bolts 33 and springs 34 allow the lower end of the fixed platen 12 to move toward the movable platen 15 when the mold is clamped, and fix the lower end of the fixed platen 12 by the urging force when closing the mold and opening the mold. It returns to the return position which contacts 31. Therefore, the spring constant of the spring 34 is set to such a value that the fixed platen 12 does not move away from the fixed block 31 with the mold closing operation and mold opening operation of the mold clamping device and the injection operation of the injection device. . The bolt 33 and the spring 34 constitute return means.
[0024]
As described above, the fixed platen 12 is movably disposed with respect to the base 11, and therefore is moved to the base plate 14 side by the tie bar 13 at the lower end and the upper end during mold clamping. Therefore, the fixed platen 12 is deformed toward the movable platen 15 as it is away from the center, and the deformation amount is equal above and below the center of the fixed platen 12. Further, the amount of elongation is equal between the upper tie bar 13 and the lower tie bar 13.
[0025]
As a result, the mold clamping force can be generated uniformly and the accuracy of the molded product can be increased.
[0026]
Next, a second embodiment of the present invention will be described.
[0027]
FIG. 8 is a schematic view of a main part of a mold clamping device according to a second embodiment of the present invention.
[0028]
In this case, the fixed platen 12 is disposed so as to be movable with respect to the base 11 and is attached to the base 11 via the attachment means 40. The attachment means 40 is attached to a cylinder body 41 of a hydraulic cylinder as a fixing member attached to the base 11 by a bolt (not shown) and a lower end portion of the fixed platen 12, and serves as a connecting member having a piston 42 at the tip. The rod 43 is provided and constitutes a hydraulic shock absorber. The cylinder 42 is partitioned by the piston 42 to form a header side oil chamber 44 as a first oil chamber and a rod side oil chamber 45 as a second oil chamber. Then, hydraulic pressure is selectively supplied to the rod-side oil chamber 45 from a hydraulic supply / discharge means of a hydraulic circuit (not shown), for example, a switching valve via a pressure adjustment valve. Reference numeral 13 denotes a tie bar, 16 denotes a fixed mold, and 17 denotes a movable mold.
[0029]
The switching valve supplies hydraulic pressure to the rod-side oil chamber 45 via a pressure regulating valve during mold clamping, so that the lower end of the fixed platen 12 moves to the movable platen 15 (FIG. 4) side with a predetermined buffering force. When the mold is closed and the mold is opened, the lower end of the fixed platen 12 is returned to a return position where the lower end of the fixed platen 12 comes into contact with the cylinder body 41 by a preset hydraulic pressure. In this case, the piston 42 and the rod-side oil chamber 45 constitute return means.
[0030]
In the hydraulic circuit, an accumulator can be provided in place of the switching valve, the pressure adjusting valve, or the like.
[0031]
In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.
[0032]
【The invention's effect】
As described above in detail, according to the present invention, in the mold clamping device, a base, a fixed platen that is movably disposed with respect to the base, and to which a fixed mold is attached, and the base A movable base plate, a tie bar installed between the fixed platen and the base plate, a movable platen disposed along the tie bar so as to be movable back and forth, and having a movable mold attached thereto, A mold clamping unit that presses the movable mold and the fixed mold to perform clamping, and an attachment unit that attaches the fixed platen to the base and allows the lower end of the fixed platen to move toward the base plate during mold clamping. And have.
The attaching means is disposed between the fixing member attached to the base and the fixing member and the fixed platen, and allows the movement of the lower end of the fixed platen when the mold is clamped. And a buffer means for returning the lower end of the fixed platen to the return position by an urging force when the mold is opened.
[0033]
In this case, since the fixed platen is movably disposed with respect to the base, the fixed platen is moved to the base plate side by the tie bars at the lower end and the upper end during mold clamping. Therefore, the fixed platen is deformed toward the movable platen as it is away from the center, and the amount of deformation is equal above and below the center of the fixed platen. Further, the amount of elongation is equal between the upper tie bar and the lower tie bar.
[0034]
As a result, the mold clamping force can be generated uniformly and the accuracy 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 mounting state of a conventional fixed platen.
FIG. 3 is a diagram illustrating a state of a conventional fixed platen during mold clamping.
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 an essential part of the mold clamping device according to the first embodiment of the present invention.
FIG. 6 is a diagram showing a state during mold clamping of the mold clamping device according to the first embodiment of the present invention.
FIG. 7 is a diagram showing a state during mold clamping of the fixed platen according to the first embodiment of the present invention.
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]
11 Base 12 Fixed platen 13 Tie bar 14 Base plate 15 Movable platen 16 Fixed mold 17 Movable mold 21 Clamping cylinders 30 and 40 Mounting means 31 Fixed block 33 Bolt 34 Spring 41 Hydraulic cylinder 42 Piston 43 Rod 45 Rod side oil chamber

Claims (3)

(A) a base;
(B) a stationary platen that is movably disposed with respect to the base and has a stationary mold attached thereto;
(C) a base plate disposed movably with respect to the base;
(D) a tie bar constructed between the fixed platen and the base plate;
(E) a movable platen disposed so as to be movable back and forth along the tie bar and having a movable mold attached thereto;
(F) mold clamping means for clamping by pressing the movable mold and the fixed mold;
(G) Attaching the fixed platen to the base and mounting means for allowing the lower end of the fixed platen to move toward the base plate when clamping.
(H) mounting means includes a fixed member attached to said base, and is disposed between the fixed platen and the fixed member, during clamping, to permit the movement of the lower end of the stationary platen, the mold closing A mold clamping device comprising a buffering means for returning the lower end of the fixed platen to a return position by an urging force at the time and when the mold is opened .   The mold clamping apparatus according to claim 1, wherein the buffer means is a mechanical type. The mold clamping apparatus according to claim 1, wherein the buffer means is hydraulic .

Images