JPS63268619A - Method and apparatus for mold clamping - Google Patents

Abstract

PURPOSE:To make it possible to reduce largely the weight of a machine without spoiling molding capability and mold clamping force, by moving mold clamping members having slopes on their inner faces in their inner direction being perpendicular to the opening and closing direction of split molds, and inserting them on slopes formed on the side walls of the split molds to press and hold them. CONSTITUTION:Slopes 28 for mold clamping are formed on side parts of split molds 10 and 18 and they constitute projected inserting parts 30 when both split molds are joined together. Mold clamping members 34 having recessed inserting parts 32 to be fitted with the projected inserting parts 30 are positioned in facing each other and moved in the lateral direction by means of a working device 36 fixed on a mold clamping box 13. Mold clamping is thereby carried out from four directions. Major part of the force generated by the split mold 10 and 18 being opening is held by these mold clamping members 34, and a divided force corresponding to a slope 28 acts on the working device 36. Therefore, a force resisting to the divided force is given by the working device 36 to hold strongly both split molds 10 and 18 in a closed state. As the result, it is possible to make largely the size of an apparatus small and to realize largely the weight-saving.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a mold clamping method and apparatus used when press-fitting a plastic material such as a synthetic resin into a molding mold and molding it. A slope is formed on the side of the split mold, and a mold clamping member having a shape that matches the slope is pressed from a direction perpendicular to the opening/closing direction of the split mold, and the split mold is closed with a small force using a wedge effect. This relates to technology that allows the device to be held in such a way that it does not open.

[Prior Art] A mold clamping device in a press-fit molding machine has a function of strongly clamping the split mold so that the split mold is not pushed open by the high-pressure plastic material press-fitted into the split mold.

Typical mold clamping mechanisms include a direct pressure type and a toggle type.

These mold clamping devices consist of a mold clamping cylinder, a fixed platen, a movable platen,
The movable platen slides using the hydraulic pressure of a mold clamping cylinder and clamps the split molds attached to the movable platen and the fixed platen respectively.

The direct pressure type applies hydraulic pressure to a reciprocating piston to move it forward and backward, thereby directly opening and closing the mold.

On the other hand, the toggle type has a structure in which the toggle link is driven by a mold clamping cylinder, and the tie bar is extended by the tension of the toggle link, and its elastic recovery force generates mold clamping force to hold the split mold.

[Problems to be solved by the invention] In any case, since the viscous plastic material is press-fitted into a split mold under high pressure and molded, the larger the molding surface area, the larger and stronger the mold clamping device will be required. It becomes necessary.

The capacity of a molding machine is generally expressed in clamped tonnage6.For example, the capacity of a synthetic resin injection molding machine is 400 kg/cm, which is required when molding a large molded product with a molding surface area of 1 m8 with high precision.
When an injection pressure of 1.5 mm is applied, the internal pressure to open the split mold reaches 4000 tons. Therefore, an extremely large injection molding machine with a mold clamping capacity of 4000 mm or more is required.

Comparing the weight and mold clamping capacity of such a super large molding machine, the molding machine weight is approximately IL in proportion to the mold clamping force of 20 t on average. In addition, the weight ratio of the mold clamping device when the molding machines are stacked reaches 65% or more. If such an average value is applied to the above-mentioned ultra-large injection molding machine, the weight of the molding machine will be approximately 200 mm or more, and of this, the weight required for the mold clamping device will be 130 mm or more.

In this way, the cost of equipment for injection molding large molded products is enormous, requiring a large installation space, and when considering machine depreciation costs and power costs, the price of molded products becomes extremely high. The number of molded pieces is 1 per ront.
In the case of small-scale production of about 1,000 pieces or less, the unit price becomes even higher, making manufacturing difficult from a cost standpoint. In other words, it is difficult to supply large injection molded products to the market at low cost, and there are significant economic constraints on the development of large products that can be made of resin.

However, in recent years, there has been an extremely strong demand in various industrial fields to economically produce large molded products from the viewpoint of streamlining manufacturing processes and sophisticated design.

The purpose of the present invention is to provide a mold clamping method that can significantly reduce machine weight without impairing molding ability or mold clamping force, and that can perform molding economically, energy-savingly, and space-savingly, in response to the above-mentioned demands. The goal is to provide equipment.

[Means for Solving the Problems] The present invention, which can achieve the above objects, consists of two inventions: a mold clamping method and a device thereof.

The first invention is to move a mold clamping member having a slope on its inner surface in an inward direction perpendicular to the opening/closing direction of the molding mold, and to apply the clamping member to the mold clamping slope formed on the side of the molding mold. This is a mold clamping method in which the molds are fitted and held under pressure, and the mold is clamped by counteracting the molding pressure applied in the opening/closing direction of the split mold with a component force in a direction substantially perpendicular to the molding pressure.

The second invention also includes a molding split mold that is attached to a fixed platen and a movable platen and can be opened and closed, and a convex fitting portion having a slope for mold clamping provided on the side of the split mold. , a mold clamping member having a concave fitting portion having a shape that matches the convex fitting portion;
The mold clamping member is provided with an actuation means for movable in a direction perpendicular to the opening/closing direction ratio of the split mold and capable of holding the mold clamping member in a mold clamping position fitted to the convex fitting portion. It is a mold clamping device.

More preferably, each of the four sides of the split mold is provided with a slope,
It is preferable that mold clamping members each having a concave fitting portion and their actuating means be arranged to face them, so that the clamping members can be clamped in a well-balanced manner in two directions.

This mold clamping device can be applied not only to horizontal molding machines but also to vertical molding machines.

[Function] The molding mold can be opened and closed by a moving means or the like. This means of transportation is only needed to open and close the split molds, so
There is no need to apply mold clamping force, and a drinking cup type is sufficient.

The mold halves have beveled sides and form a convex fitting when assembled. Mold clamping is performed by driving a mold clamping member having a concave fitting portion that exactly matches this convex fitting portion in a direction perpendicular to the opening/closing direction of the split mold. During molding, a large force acts to open the split mold, but depending on the slope, this force can be divided into a component in a direction perpendicular to the slope and a component in a direction parallel to the slope. The component in the direction perpendicular to the slope is held by its own strength by using a strong mold clamping member, and only the component force in the parallel direction appears as a force that tries to move the mold clamping member. . Therefore, if an actuation means for the mold clamping member is provided so as to be able to resist this relatively small force, the two split molds can be firmly held even with a relatively small actuation means.

As a result, the device can be significantly reduced in size and weight.

[Example] Figures 1 to 4 show an example of a mold clamping device according to the present invention, and Figure 1 is a front sectional view of the split mold in an open state;
FIG. 2 is a plan view thereof, FIG. 3 is a front sectional view of the split mold in a closed state, and FIG. 4 is a plan view thereof.

One split mold 10 is attached to a fixed platen 12, and the fixed platen 12 is installed in a mold clamping box 13. The mold clamping box 13 is supported on a support 16 erected from a pedestal 15 on the foundation 14. The other split mold 18 is the movable platen 2
o and supported by a stay 22. Stay 2
2 is fitted with a sliding table 25, and can be raised and lowered by means of a vertical movement means 24 consisting of a hydraulic cylinder or the like. Note that the fixed side split mold 10 has a zero split mold 1 in which a plastic injection port 26 is formed.
The inner surface 10a of the mold 0 and the upper surface 18a of the other split mold 18 serve as molding surfaces.

Now, one feature of the present invention is that such molding molds 10,
A mold clamping slope 28 is formed on the side of 1B, and when the two split molds are matched, a convex fitting portion 3° is formed (see FIG. 3). In this embodiment, a convex portion is provided on each of the four sides of each molding split mold 10, 18, and the outer surface of the convex portion, that is, the upper surface of the fixed side split mold lO, is on the movable side. Each of the lower surfaces of the split mold 18 has a slope 28.

The cross section of the concave fitting part 32 having a shape that matches the convex fitting part 3o is such that a substantially U-shaped mold clamping member 34 is located opposite to the mold clamping member 34, and is attached to the mold clamping box 13 in the lateral direction. It is constructed so that it can be moved laterally by means of actuating means 36 which are movable.

The operation of the mold clamping device configured as described above is as follows.

The split mold 18 attached to the movable platen 20 is moved up and down by the vertical moving means 24 to open and close the split mold. This movable platen 20 slides only up and down without lateral wobbling due to the guide in the sliding table 25, and the required stroke is covered by the pedestal 15. It's down to the bottom.

When clamping the mold during molding, as shown in FIGS. 3 and 4, the movable platen 20 is raised by the moving means 24 to close the fixed-side split mold 10 and the movable-side split mold 18. As a result, convex fitting portions 30 are formed on the four side surfaces. A concave fitting part 32 of a mold clamping member 34 faces this convex fitting part 30, and is driven horizontally by an actuating means 36 to perform mold clamping from four directions. After B4 like this,
The plastic material is press-fitted from the press inlet 26 under high pressure.

Due to this high-pressure press-fitting, force is applied in the direction in which the split molds 10 and 18 try to open, but the mold clamping member 34 having the concave fitting portion 32 is made of a thick steel material with sufficient mechanical strength. Most of the force which tends to open both mold halves 10.18 is held by this mold clamping member 34, and a component of the force corresponding to the slope 28 is applied to the actuating means 36. Therefore, by applying a force capable of counteracting this force by the actuating means 36, the split molds 10, 18 can be firmly held in the closed state.

When the high-pressure press-fitting of the plastic material is completed and the plastic material is cooled, the filled resin and the like contract, so the vertical force disappears, and the mold can be easily opened and the molded product taken out. To do this, the actuating means 36 is moved to open the mold clamping member 34 outward and the movable platen 20 is lowered.

In this way, mold clamping is performed exclusively by the mold clamping member 34 and its operating means 36.
Since the support has a support, the moving means 24 for moving the movable platen 20 up and down applies enough pressure to close and press the movable split mold 18 against the fixed split mold lO fixed to the mold clamp box 13. Since it is only necessary to be able to apply the pressure and move the stroke required for opening and closing, a relatively small drive mechanism (such as a hydraulic cylinder) is sufficient and power consumption is low.

For example, considering the case of a mold clamping force of 4000 t, the fitting depth of the concave fitting part 32 is about 12 cm,
A slope 28 of about 1,720 degrees is provided to serve as a mold clamping slope and a mold removal slope. If such a slope 28 is provided, the force that spreads the mold clamping member 34 in the vertical direction is applied to the sloped surfaces on both sides of the fitting surface, so the lateral component force is approximately 1/40 of IO.
It becomes 0t. If this component force of 400 t is divided into the actuating means 36 for the mold clamping member at four locations, the pressure of 100 t will be less than or equal to 100 t, respectively, and the molding pressure of 4000 t can be resisted by these components. In addition, the movement distance of the actuating means is only about 15 cm, and a relatively small hydraulic cylinder can suffice, and the power used therein is also extremely small.

Therefore, in the case of an injection molding machine with a mold clamping capacity of 4,000 tons, the weight of the machine was approximately 200 tons or more as described above in the conventional technology, but according to the present invention, it is possible to manufacture a machine with a weight of about 1/4 of that, about 50 tons. Moreover, the required power is about 173 times lower than that of the conventional technology.
It's enough.

FIGS. 5 and 6 are a front view and a plan view showing the structure of a vertical injection molding machine for synthetic resin using the present invention. The parts of the mold clamping device 50 may be the same as those in the previous embodiment, so a description thereof will be omitted. The resin thermoplasticized by the extruder 51 is filled and stored in the extrusion chamber 52, and the resin stored in the extrusion chamber is press-fitted at high pressure into a split mold having a press inlet as shown in FIG. 3 in the mold clamping box. and form it.

7 to 9 show the case where the present invention is applied to a horizontal injection molding machine. The basic idea is the same as that described in FIGS. 1 to 4.

Therefore, to simplify the explanation, corresponding parts are given the same reference numerals. An extruder 62 having an injection means is disposed on one side of a laterally long lower frame 60, and a mold clamping device 64 is placed horizontally.

In this embodiment, the movable mold split 18 moves horizontally. As is clear from FIGS. 7 and 9, the movable platen 2
0 is driven by the moving means 24 in the right-hand direction in the drawing, and is clamped by the mold clamping member 34 that moves toward the center in a vertical plane. The moving means 24' that moves the movable platen 20 to open and close the split molds 10 and 1B has the main role of simply crimping the movable split mold 18 to the fixed split mold lO of the mold clamping box 13 and opening the mold. Therefore, a hydraulic cylinder with a long stroke and a small outer diameter may be used.

The enormous molding pressure applied to the mold split molds 10 and 18 is due to the own strength of the mold clamping member 34, which clamps the mold from a direction perpendicular to the opening/closing direction of the split molds, and the actuating means 36 provided behind it. I can compete well.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to only such a configuration. Although the actuating means 36 is disposed, in some cases, the mold clamping members and their actuating means may be provided only in one direction facing each other, or both mold clamping members disposed facing each other may be operated respectively. It is desirable to have a structure that allows movement by a means, but in some cases, one may be fixed and only the other may be moved by an actuating means.

Furthermore, the split mold used in the present invention has the function of itself as a mold, but in some cases it may be a combination of a mold clamping holder and a mold body, so that only the mold body can be replaced. It is also effective to have a structure. In other words, in that case, the mold clamping holder and the mold body constitute a split mold as referred to in the present invention. By doing so, it becomes possible to easily handle various molded bodies having different shapes.

[Effects of the Invention] As described above, the present invention provides a mold clamping member formed on the side of a mold split mold by moving the mold clamp member having a slope on the inner surface in a direction perpendicular to the opening/closing direction of the mold split mold. The mold clamping member holds most of the molding pressure in the opening/closing direction of the split mold by its own strength, and the remaining component force is applied in the direction almost perpendicular to the opening/closing direction of the split mold. Since the mold is configured to be clamped by pressure, the weight ratio of the mold clamping mechanism to the weight of the molding machine can be significantly reduced, unlike the conventional direct pressure type or toggle type mold clamping mechanism.

Therefore, the present invention is particularly effective when molding plastic materials such as synthetic resins and ceramics using split molds with a large molding area. Since the mold opening is prevented by the strength of the members and the movement of the mold clamping member is regulated by means of actuating a relatively small pressing force, it is possible to obtain a compact, lightweight and highly economical mold clamping device. , it is possible to sufficiently handle large-sized molded bodies produced in high-mix, low-volume production, which was previously not economically viable. In particular, by using a split mold as a clamping holder, molded bodies of various shapes can be easily manufactured.

Furthermore, in the present invention, the moving means for opening and closing the molding molds only needs to have the function of opening and closing the molding molds, and as mentioned above, the force of the actuating means used for mold clamping can be small, so the required installation space is reduced. The mold clamping technology is also smaller and requires significantly less power than conventional mold clamping technology.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the mold clamping device according to the present invention in a split mold open state, FIG. 2 is a plan view thereof, and FIG. 3 is a front view showing the split mold in a closed state. 4 is a plan view thereof, FIG. 5 is a front view showing an example of the application of the device according to the present invention to a vertical injection molding machine, FIG. 6 is a plan view thereof, and FIG. 7 is a main view. FIG. 8 is a front view showing an example of a horizontal injection molding machine to which the apparatus according to the invention is applied, FIG. 8 is a side view thereof, and FIG. 9 is a plan view thereof. 10... Fixed side split mold, 12... Fixed plate, 14...
・Foundation, 18... Movable side split mold, 2o... Movable plate,
24... Moving means, 28... Slope, 3o... Convex fitting part, 32... Concave fitting part, 34... Mold clamping member,
36... Actuation means. Patent Applicant: 1) Yumei Patent Applicant: 1) Sei Yuka Rinto Shigeru Miyoshi Figure 1 Figure 3yJ Figure 2 Figure 14

Claims (1)

[Claims] 1. A mold clamping slope formed on the side of the mold split mold by moving a mold clamping member having a slope on the inner surface in an inward direction perpendicular to the opening/closing direction of the mold split mold. A mold clamping method characterized by fitting and holding the mold under pressure, and clamping the mold by counteracting the molding pressure applied in the opening/closing direction of the split mold with a component force in a direction substantially perpendicular to the molding pressure. 2. A molding split mold that is attached to a fixed platen and a movable platen and can be opened and closed, a convex fitting part having a mold clamping slope provided on the side of the split mold, and the convex fitting part. a mold clamping member having a concave fitting portion having a shape that matches the mold portion; and a mold clamping member that is movable in a direction orthogonal to the opening/closing direction of the split mold and that is fitted in the convex fitting portion. A mold clamping device, characterized in that it is equipped with an actuating means for a mold clamping member that can be held in position.