JP3915009B2 - Clamping device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold clamping device such as an injection molding machine, and more particularly to a mold clamping device including a guide mechanism that reliably guides movement of a mold when the mold is opened and closed.
[0002]
[Prior art]
The mold clamping device of the injection molding machine moves the movable side mold plate back and forth with respect to the fixed side mold plate, maintains these mold plates in a closed state when injecting molding raw materials, and takes them out when taking out the molded product. A mechanism is provided in which the mold plates are separated to make the mold open. In order to perform reliable molding, the positional relationship between these mold plates in the mold closed state must be constant. For this reason, a guide mechanism for guiding the advance and retreat of the movable side template is provided.
[0003]
3 to 5 are schematic views for explaining a mold clamping device provided with a conventional guide mechanism. An upper mold plate 2 that is a fixed-side mold plate is provided above the mold clamping device 1, and an upper mold 3 is fixed to the upper mold plate 2. A lower mold plate 5 that is a movable mold plate that can be moved up and down by a driving device 4 is disposed below the upper mold plate 2, and a lower mold 6 is fixed to the lower mold plate 5. The upper mold plate 2 is supported at its four corners by a main stay 8 fixed upright on a gantry 7 of the mold clamping device 1, and the main stay 8 passes through each of the four corners of the lower mold plate 5. The lower mold plate 5 is guided up and down. A guide pin 3a is projected from the upper mold 3, and a guide bush 6a is formed in the lower mold 6 by a hole through which the guide pin 3a can be inserted and removed. That is, the guide pin 3a is inserted into the guide bush 6a when the mold is closed, and the upper mold 3 and the lower mold 6 are positioned at predetermined positions and maintained in a predetermined mold closed state. 3a is extracted from the guide bush 6a.
[0004]
By the way, in order to maintain the molding raw material supplied into the molds 3 and 6 at an appropriate temperature at the time of molding, the molds 3 and 6 are maintained at an appropriate temperature by a temperature adjusting device (not shown).
[0005]
[Problems to be solved by the invention]
The temperature of the mold is also transmitted to the upper and lower mold plates 2 and 5. In particular, when the molds 3 and 6 are maintained at a high temperature and the heat is transferred to the mold plates 2 and 5, the mold plates 2 and 5 expand greatly. In addition, when the templates 2 and 5 are expanded, they expand substantially in the diagonal direction. FIG. 4 is a schematic plan view showing a state when the upper mold plate 2 is expanded, and shows a case where the upper mold plate 2 is expanded in a diagonal direction. A support hole 2a through which the main stay 8 is penetrated is shown in FIG. What was in the position indicated by the broken line before the expansion moves to the position indicated by the solid line. In addition, the upper mold plate 2 and the lower mold plate 5 do not have the same expansion rate, and therefore the expansion amount is different. For this reason, as shown in FIG. 5, the upper part of the lower mold plate 5 of the main stay 8 may be inclined. In such a state, even if the lower mold plate 5 is raised for mold closing, the guide pin 3a and the guide bush 6a do not coincide with each other, and the upper and lower molds 3, 6 at the time of mold closing are not matched. There is a possibility that the accuracy of the molded product will be lowered due to the position of the shift of the position, or that the mold cannot be closed.
[0006]
Further, the upper mold plate 2 bends due to secular change or the like, and this may cause a decrease in alignment accuracy when the upper and lower mold plates 2 and 5 are closed.
[0007]
Therefore, the present invention reduces the alignment accuracy of the mold when the mold is closed even when heat is transferred from the mold and the upper and lower mold plates are deformed or when the mold plates are deformed due to aging. It is an object of the present invention to provide a mold clamping device that prevents this from happening.
[0008]
[Means for Solving the Problems]
As a technical means for achieving the above object, the mold clamping device according to the present invention is configured to move the movable side mold plate forward and backward with respect to the fixed side mold plate, thereby In the mold clamping device that opens and closes, a fixed mold is attached with a sub plate interposed in the fixed mold plate, a movable mold is attached with a sub plate interposed in the movable mold plate , The inner cylinder and the outer cylinder of the cylindrical guide device each composed of a double cylinder are fixed to each other, and the main stay that supports the fixed side mold plate and penetrates the movable side mold plate is attached to the cylindrical guide device. The sub-plate is guided by the cylindrical guide device when the movable side mold plate is advanced and retracted.
[0009]
When moving the movable side mold plate relative to the fixed side mold plate, the sub-plate is guided by the cylindrical guide device. Therefore, regardless of the positional relationship between the fixed side mold plate and the movable side mold plate, The sub-plate attached to the template approaches and separates while maintaining a predetermined positional relationship. Since the molds are attached to these sub-plates, the fixed side mold and the movable side mold also advance and retreat with a predetermined positional relationship maintained. For this reason, the positional relationship of these dies does not shift when the mold is opened and closed. Therefore, the mold can be reliably opened and closed even when the template expands or deforms due to aging.
[0011]
Further, since using the cylinder type guide device, can Rukoto is loosely inserted to the main stay inside the cylinder, installation space can be reduced for the cylindrical type guide device, is not the size of the mold clamping device .
[0012]
Further, the mold clamping device according to the invention of claim 2 is provided with attachment holes for attaching the sub-plates to the fixed-side mold plate and the movable-side mold plate with fixing bolts, respectively, and for inserting the fixing bolts formed in the sub-plate. The sub-plate is formed by a long hole whose longitudinal direction is the extension direction when the sub-plate is thermally expanded .
[0013]
When the subplate thermally expands due to heat transfer from the mold, the mounting hole formed by the elongated hole shifts its insertion position with respect to the fixing bolt and absorbs deformation due to expansion. Deformation is allowed.
[0014]
According to a third aspect of the present invention, the mold clamping device is characterized in that a bending absorbing gap is formed between the peripheral edge portion of the sub-plate attached to the fixed-side mold plate and the fixed-side mold plate.
[0015]
When the fixed side template is bent due to secular change, the bending absorbing gap absorbs the bent portion. For this reason, it can prevent that the deformation | transformation by bending of a stationary side template influences the alignment precision of a metal mold | die. Further, if the edge of the gap for absorbing bending is positioned on the inner side of the edge of the mold, the bending moment generated by the reaction force at the time of closing the mold is not transmitted to the sub-plate, and the sub-plate is not transmitted. The load is not.
[0016]
According to a fourth aspect of the present invention, the mold clamping device is characterized in that a temperature adjusting means is provided on the sub plate to adjust the temperature of the sub plate.
[0017]
Since the heat of the mold is transmitted to the sub-plate, there is a risk of expansion and deformation due to this heat. For this reason, temperature adjusting means is provided so that the deformation amounts of the sub-plates are made substantially equal by making the temperatures of the sub-plates attached to the fixed-side mold plate and the movable-side die plate substantially equal. As the temperature adjusting means, for example, a pipe line is provided inside the sub plate so that the temperature adjusting medium flows.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The mold clamping device according to the present invention will be specifically described below based on the preferred embodiments shown in FIGS. The mold clamping device 10 is appropriate for use in an injection molding machine, and a vertical mold clamping device 10 is illustrated.
[0021]
A substantially rectangular frame 11 is arranged at the lower part of the mold clamping device 10, and main stays 12 are installed upright at the four corners of the frame 11. An upper mold plate 13 as a fixed-side mold plate is supported and fixed to the upper end portion of the main stay 12. The main stay 12 passes through insertion holes 14a formed at the four corners of the lower mold plate 14 as a movable mold plate, and the movable mold plate 14 is slidable with respect to the main stay 12. . The movable side template 14 is moved up and down by the operation of the driving device 20 including a piston and a cylinder.
[0022]
An upper sub-plate 15 is attached to the lower surface of the upper mold plate 13 with fixing bolts 16. A mounting hole 15a formed in the upper sub-plate 15 for allowing the fixing bolt 16 to pass therethrough is formed as a long hole whose longitudinal direction is the extension direction when the upper sub-plate 15 is thermally expanded. In addition, a deflection absorbing gap 17 of an appropriate distance is formed between the peripheral edge portion of the upper sub-plate 15 and the upper mold plate 13. As shown in FIG. 1, the edge portion of the deflection absorbing gap 17 is positioned on the inner side of a peripheral portion of a mold, which will be described later, fixed to the upper sub-plate 15. Further, a pipe line is formed on the upper sub-plate 15 through an appropriate path, and a temperature adjusting medium is introduced into the pipe line. An inlet hole 15b for communicating the pipe line with the outside is formed on the side surface of the upper sub-plate 15, and a temperature adjusting medium is supplied from the inlet hole 15b by a medium supply device (not shown).
[0023]
A lower sub-plate 18 is attached to the upper surface of the lower mold plate 14 with fixing bolts 19. The mounting hole 18a formed in the lower sub-plate 18 for allowing the fixing bolt 19 to pass therethrough is a length having the extension direction when the lower sub-plate 18 is thermally expanded as the longitudinal direction, like the mounting hole 15a. It is formed with holes. Further, a pipe line is formed on the lower sub-plate 18 through an appropriate path, and a temperature adjusting medium is introduced into the pipe line. Further, an introduction hole 18b for communicating the pipe line with the outside is formed on the side surface of the lower sub-plate 18, and a temperature adjusting medium is supplied from the introduction hole 18b by a medium supply device (not shown).
[0024]
A slight gap is formed between the upper mold plate 13 and the upper subplate 15 and between the lower mold plate 14 and the lower subplate 18. FIG. 2 is a cross-sectional view showing how the upper mold plate 13 and the upper sub-plate 15 are attached. A counterbore is formed in a screw hole in which the fixing bolt 16 of the upper mold plate 13 is screwed, and the tip of the bush 16a is inserted into this counterbore. The length of the bush 16a excluding the portion inserted into the counterbore is larger than the thickness of the mounting hole 15a. The fixing bolt 16 fixes the upper sub-plate 15 with a washer plate 16b appropriately larger than the mounting hole 15a. Therefore, as shown in the figure, a slight gap 13a is formed between the upper mold plate 13 and the upper sub-plate 15. Similarly, a gap (not shown) is also formed between the lower mold plate 14 and the lower sub-plate 18.
[0025]
On the other hand, a fixed mold 21 is fixed to the upper subplate 15, and a movable mold 22 is fixed to the lower subplate 18. A guide pin 21a that protrudes downward is provided at an appropriate position of the fixed mold 21. The guide pin 21a is inserted and removed at a position where the guide pin 21a of the movable mold 22 faces. A guide bush 22a is formed by a hole that is freely inserted. When the lower mold plate 14 is raised, the guide bush 22a is fitted into the guide pin 21a, and the fixed side mold 21 and the movable side mold 22 are in a predetermined positional relationship to close the mold. .
[0026]
Then, the upper and lower sub-plates 15 and 18, are allowed to interlocking cylindrical type guide device 24. This cylindrical guide device 24 is constituted by a cylindrical device in which an inner cylinder 25 and an outer cylinder 26 are combined so as to be in an appropriate clearance fit, and the inner cylinder 25 and the outer cylinder 26 are composed of By sliding against each other, it contracts and guides the direction of movement. Flange portions 25a and 26a are formed at the end portions of the inner cylinder 25 and the outer tube 26, and the flange portions 25a and 26a are fixed to the upper subplate 15 and the lower subplate 18 with set screws 27, respectively. Thus, the sub-plates 15 and 18 are connected to the cylindrical guide device 24 . The main stay 12 is loosely inserted into the inner cylinder 25 and the outer cylinder 26.
[0027]
Note that a heating cylinder 30 of an injection device is connected to the upper mold plate 13, and molding raw materials are supplied to the molds 21 and 22 through the upper mold plate 13 and the upper sub-plate 15.
[0028]
The operation of the mold clamping apparatus 10 according to the embodiment of the present invention configured as described above will be described below.
[0029]
When closing the mold, the driving device 20 is operated to raise the lower mold plate 14 and advance or raise the movable mold 22 toward the fixed mold 21. At this time, the lower mold plate 14 is raised by being guided by the main stay 12. As the lower mold plate 14 is raised, the lower sub-plate 18 is also raised, and the outer cylinder 26 fixed to the lower sub-plate 18 is pushed up. Since the outer cylinder 26 is fitted to the inner cylinder 25, the outer cylinder 26 is guided by the inner cylinder 25 and rises.
[0030]
On the other hand, since the inner cylinder 25 is fixed to the upper subplate 15, the outer cylinder 26 moves upward while maintaining a fixed position with respect to the upper subplate 15. Accordingly, the lower sub-plate 18 to which the outer cylinder 26 is fixed moves while maintaining a fixed position with respect to the upper sub-plate 15, so that the movable mold 22 is fixed with respect to the fixed mold 21. It will rise due to the positional relationship. When the movable mold 22 is moved up to an appropriate position, the guide bush 22a is inserted into the guide pin 21a of the fixed mold 21, and the molds 21 and 22 are guided by the engagement between the guide bush 22a and the guide pin 21a. And closed in a predetermined positional relationship.
[0031]
With the molds 21 and 22 closed, the molding raw material is supplied into the mold and molding is performed.
[0032]
When the molding is completed, the driving device 20 is operated to lower the lower mold plate 14, and the movable side mold 22 is separated from the fixed side mold 21 to perform mold opening. At this time, the retraction, that is, the lowering of the movable side mold 22 with respect to the fixed side mold 21 is also guided by the cylindrical guide device 24.
[0033]
When molding the molding raw material, the molds 21 and 22 are heated so that the molding material supplied into the molds 21 and 22 flows appropriately and is reliably filled in the molds 21 and 22. Thus, the fluidity of the forming raw material is maintained at a high temperature. When the heat applied to the molds 21 and 22 is transmitted to the sub plates 15 and 18, the sub plates 15 and 18 may expand and deform. On the other hand, since the temperature adjusting medium is supplied to the pipe lines formed in the sub-plates 15 and 18 through the introduction holes 15b and 18b, the temperature of the temperature adjusting medium is adjusted respectively. Thus, the sub-plates 15 and 18 are always maintained at substantially the same temperature. For this reason, the deformation amounts due to the thermal expansion of these sub-plates 15 and 18 are substantially equal. Then, with respect to the fixing bolt 16 that fixes the sub-plates 15 and 18 to the upper mold plate 13 and the lower mold plate 14, the mounting holes 15a that pass through the fixing bolts 16 are displaced in the longitudinal direction, whereby the sub-plate 15, 18 expansions are allowed. In addition, a gap 13a is formed between the upper mold plate 13 and the upper subplate 15, and the upper mold plate 13 and the upper subplate 15 are configured to move relative to each other. Since the lower sub-plate 18 is also configured to move relative to each other, the sub-plates 15 and 18 can expand without receiving resistance from the template plates 13 and 14.
[0034]
The cylindrical guide device 24 that is connected and fixed to the sub-plates 15 and 18 that are deformed by substantially the same amount always guides the movement of the sub-plates 15 and 18 that maintain a fixed positional relationship. Therefore, the fixed side mold 21 and the movable side mold 22 can be reliably opened and closed by reliably guiding.
[0035]
Further, since the upper mold plate 13 is provided on the upper part of the main stay 12, its own weight is constantly applied, and when the mold is closed, a reaction force of the clamping force is applied to the peripheral edge of the upper mold plate 13. Although it is repeatedly applied and may be bent due to aging, this bending is absorbed by the bending absorbing gap 17 and does not affect the sub-plate 15. In particular, since the bending absorbing gap 17 is formed so as to reach the inner side of the peripheral portion of the mold 21, a bending moment due to the deformation of the peripheral portion of the upper mold plate 13 is not applied to the sub-plate 15.
[0036]
【The invention's effect】
As described above, according to the mold clamping device according to the present invention, since the mold is opened and closed by moving the sub plate to which the mold is attached by the cylindrical guide device, the mold plate is thermally expanded and others. Even if it is deformed by the above, as long as the sub-plates are maintained in a predetermined positional relationship, the mold does not shift when the mold is closed. For this reason, the opening / closing operation | movement of a metal mold | die can be performed reliably.
[0037]
Moreover, since the sub-plates provided on the template plate are fixedly connected to the inner cylinder and the outer cylinder of the cylindrical guide device, the structure can be simplified and the existing mold can be used. The fastening device can be easily modified to this structure.
[0038]
Furthermore, the space for installing the cylindrical guide device is minimized, and the mold clamping device is not enlarged.
[0039]
According to the mold clamping device of the second aspect of the present invention, the deformation of the sub plate due to thermal expansion or the like is absorbed by the mounting hole of the sub plate, and the connection relationship between the cylindrical guide device and the sub plate is a predetermined relationship. Can be easily maintained.
[0040]
According to the mold clamping device of the invention of claim 3 , since the deformation of the template due to the repeated load due to opening and closing of the mold and the bending caused by the secular change is absorbed by the bending absorbing gap, the amount of deformation of the template is reduced. It can be made as small as possible.
[0041]
Further, according to the mold clamping device according to the invention of claim 4, since the upper and lower subplates are held at substantially the same temperature by the temperature adjusting means, when these subplates are deformed by heat or the like, any of the subplates The deformation amounts are substantially equal, the positional relationship with the cylindrical guide device can be maintained constant, and the opening and closing of the mold can be reliably guided.
[Brief description of the drawings]
FIG. 1 is a schematic front view for explaining the structure of a mold clamping device according to the present invention.
FIG. 2 is a partial cross-sectional view for explaining a mounting relationship between an upper mold plate and a sub plate of the mold clamping device according to the present invention.
FIG. 3 is a schematic front view for explaining the structure of a conventional mold clamping device.
FIG. 4 is a schematic plan view for explaining problems of a conventional mold clamping device.
FIG. 5 is a front view of a mold clamping device for explaining problems of the conventional mold clamping device.
[Explanation of symbols]
10 Clamping device
12 Main stay
13 Upper template (fixed side template)
14 Lower mold plate (movable side plate)
14a Insertion hole
15 Upper sub-plate
15a Mounting hole
15b Introduction hole
16 Fixing bolt
17 Bending absorption gap
18 Lower sub-plate
18a Mounting hole
19 Fixing bolt
20 Drive unit
21 Fixed side mold
22 Movable mold
24 cylindrical guide device
25 inner cylinder
26 outer cylinder
27 Set screw

Claims (4)

In the mold clamping device that opens and closes the mold attached to each of these mold plates by moving the movable mold plate back and forth with respect to the fixed mold plate,
Attach a fixed mold with a sub-plate interposed in the fixed mold plate,
A movable side mold is attached with a sub plate interposed in the movable side mold plate,
The inner cylinder and the outer cylinder of the cylindrical guide device made of a double cylinder are respectively fixed to each of the sub plates ,
The main stay that supports the fixed side mold plate and penetrates the movable side mold plate is loosely inserted into the cylindrical guide device,
A mold clamping device, wherein the sub-plate is guided by the cylindrical guide device when the movable side mold plate advances and retreats. The sub plate is attached to the fixed side mold plate and the movable side mold plate with fixing bolts, respectively.
2. The mold clamping device according to claim 1, wherein the attachment hole into which the fixing bolt formed in the sub plate is inserted is formed as a long hole with an extension direction when the sub plate is thermally expanded as a longitudinal direction . 3. The mold clamping device according to claim 1, wherein a bending absorbing gap is formed between a peripheral edge portion of a sub-plate attached to the fixed side mold plate and the fixed side mold plate. The mold clamping device according to any one of claims 1 to 3 , wherein a temperature adjusting means is provided on the sub plate to adjust the temperature of the sub plate.

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