JPH1094864A - Method and device for clamping injection forming die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a smooth straightening work with an optimum hydraulic oil by changing the hydraulic oil to be fed into plural closed bags according to the gap value between bent dies. SOLUTION: The bending between a movable die 15 and a fixed die 16 is straightened and controlled so that the both dies are made perpendicular and the gap between both dies 15, 16 is eliminated. Firstly, a gap sensors 82 are arranged at the position having the same surface as the parting surface of the fixed die 16. The closed bags 73 and the gap sensors 82 are integrally arranged at the front surface and the back surface and the gaps S obtd. with the gap sensors 82 are transferred as the information of the gap S to each closed bag 73 positioned at the back surface part corresponding to the gap sensor 82. The straightening force according to the gap S is applied to the back surface of the fixed die 16, and the bent fixed die 16 is straightened so as to become the vertical state. By this method, the constitution of the hydraulic oil supplying device can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding mold clamping method and apparatus which is attached to an injection molding machine such as a die casting machine or an injection molding machine and moves a movable mold to and from a fixed mold to perform mold clamping. Things.

[0002]

2. Description of the Related Art For example, injection molding machines such as a die casting machine and an injection molding machine are classified into a vertical mold and a horizontal mold according to a mold clamping direction, and a vertical injection mold according to an injection direction of a molten material or a plastic material. The die-casting machine is classified into a die and a horizontal injection die. Among them, for example, a vertical die-casting die-casting machine is generally configured as follows. That is, tie rods are erected at the four corners of the fixed platen fixed on the machine base, and a cylinder platen whose plane is opposed to the plane of the fixed platen is supported on the upper step of these tie rods. The cylinder platen is fixed by a nut screwed into a thread portion of a tie rod. Also 4
A movable platen is slidably fitted in the hole of the tie rod, and the movable platen has a working end of a main ram which advances and retreats by hydraulic pressure in a ram hole provided in the center of the cylinder platen. Fixed.

[0003] On the opposing surfaces of the fixed platen and the movable platen, a fixed mold and a movable mold whose planes are opposed to each other are mounted. Further, a plunge tip on the injection cylinder side disposed below the fixed platen is fitted to the injection sleeve supported on the injection cylinder side so as to be able to advance and retreat, and the injection sleeve is fixed on the fixed platen side. The inner hole of the fixed sleeve is connected to the cavity of the mold via the runner of the fixed mold.

[0004] With this configuration, when the main ram advances by hydraulic pressure, the movable platen integrated with the main ram moves with the movable mold and is clamped to the fixed mold. Then, when the molten metal is injected into the injection sleeve and joined to the fixed sleeve, and the plunger tip is advanced by the hydraulic pressure of the injection cylinder, the molten metal in the injection sleeve is injected into the mold cavity through the fixed sleeve and the runner. You. Then, after the molten metal in the cavity is solidified, when the piston rod of the mold clamping cylinder is retracted, the movable mold is retracted and the mold is opened, so that the product which is the molten metal solidified product held in the movable mold is removed. Withdrawal completes one molding cycle.

[0005]

However, in such a conventional mold clamping apparatus for injection molding, when the movable platen is moved by the mold clamping cylinder and the mold is clamped, the movable platen and the fixed metal which hold the movable mold are provided. Since the fixed platen holding the mold is pressed more strongly at the center than at the four peripheral parts, the movable platen and the fixed platen are moved to the center by four.
It will bend so as to be larger than the peripheral part. In particular, the fixed platen on which the fixed mold having a lower rigidity than the movable mold is mounted will bend more than the movable platen.
In the case of a large injection molding device such as 4000 tons,
The center of the upper surface of the fixed platen is curved so as to be deformed by 1 to 2 mm.

As a result, the fixed mold also bends and the shape of the mold cavity changes, so that a molded product having an accurate shape and dimensions cannot be obtained. Will erupt. In particular, if small foreign matter adheres or is damaged near the outer periphery of the mating surface of the mold, the molten material leaks vigorously from the gap of the mold, which is dangerous. There is a problem that the work efficiency after taking out the product is reduced due to bleeding.

In order to solve such a problem, for example, Japanese Unexamined Patent Application Publication No. 04-262848 discloses a method in which both the fixed platen 2 and the movable platen or only the fixed platen 2 is moved toward the mold as shown in FIG. Opening cylinder hole 2
b was provided. A ram cylinder 2 having a ram 29 protruding from the cylinder hole 2b by fluid pressure in the cylinder hole 2b.
4 discloses that the surface of the movable mold and the fixed mold that are to be bent at the time of mold clamping by operating the ram cylinder 24 by the operation of the ram cylinder 24 are horizontal. However, in Japanese Unexamined Patent Publication No. H04-262848, a gap is formed between the cylinder hole 2b and the ram 29 when the fixed mold having a lower rigidity than the movable mold is bent during mold clamping.
A new problem arises that the hydraulic pressure for pressing 9 leaks from this gap.

Japanese Patent Application Laid-Open No. 04-262848 discloses that when the nut member 64 is rotated by the AC servomotor 70 and the male screw member 57 is moved in the direction of arrow R as shown in FIG. Movable board 59 together with operation board 58
Are moved in the same direction, and the fixed mold 61 and the movable mold 6 are moved.
The molding die 60 composed of 2 is closed. The hydraulic operating panel 58 is fixed to the tie bar 64 by the split clamp 63, the male screw member 57 is moved in the direction of the arrow R, and the filled liquid pressing portion 65 is projected into the closed chamber 66. Filled liquid pressing part 65
The sealing liquid 67 is pressed by the large-diameter portion 68 due to the protrusion. The filling liquid 67 is slightly compressed, and a pressure corresponding to the pressing force of the large diameter portion 68 is generated. This pressure is applied to the piston 6
A structure that acts as a mold clamping force on a molding die 60 via a movable plate 9 and a movable plate 59 is disclosed.

However, the filled liquid pressing portion 65 repeatedly protrudes into the closed chamber 66 to press the filled liquid 67 in the sealed bag 70, and the repetitive operation on the sealed bag 70 causes the filled liquid pressing portion 65. There is a problem that the pressed local portion of the sealing bag 70 becomes brittle and breaks, and the sealed liquid 67 of the sealing bag 70 easily leaks to the outside.

Further, Japanese Utility Model Laid-Open No. 04-104258 discloses that a hollow die connected to a pressurized air source is provided near a central axis of a mold holding platen having tie rods at a plurality of corners. It is described that the inflation bag was buried in contact with the plate-facing surface of the platen, and when pressurized air was supplied to the inflation bag to press the inflated inflation bag against the mold, the mold was closed. Even if the platen is bent by force, the center of the rear surface of the mold can be pressed so as not to bend, and a molded product with an accurate shape and dimensions can be obtained reliably and easily. .

However, the gap value when the mold is curved is largest at the center portion and gradually decreases toward both ends, and in order to correct such a gap value,
A disk-shaped or donut-shaped inflatable bag is disposed on the back of the fixed mold, and pressurized air is supplied to the inflatable bag. However, the inflatable bag has a flat and large diameter (approximately slightly smaller than the size of the fixed mold). When the inflatable bag is inflated by supplying pressurized air to it, it curves according to the principle of Pascal. A uniform correction force acts on the entire fixed mold back surface. Originally, the largest straightening force acts on the central part of the fixed mold with the largest gap value, and the gap value becomes smaller toward the end of the mold, so it is desirable to reduce the straightening force accordingly. Since the correction force corresponding to the gap at the center is applied, the same correction force acts on the end of the mold with a small gap value as at the center with a large gap value, and there is a problem that there is much waste.

The present invention has been made in view of the above-described points, and the size of the gap value between the dies is adjusted so that the dies do not bend even if the platen slightly curves during the clamping and injection. It is an object of the present invention to provide a mold clamping method and apparatus for injection molding in which a pressurized oil supplied to an inflatable bag is correspondingly fed to correct a curved mold.

[0013]

In order to achieve the above object, according to a first aspect of the present invention, a plurality of hermetically sealed bags for correcting a fixed mold bent by mold clamping are provided in a fixed platen. A gap between both curved dies is disposed so as to be in contact with the mold facing surface, and a gap sensor is arranged at a position having the same surface as the fixed mold parting surface between the fixed mold and the movable mold. The pressure oil to be sent to the plurality of sealed bags is changed according to the size of the gap value. In the second invention mainly based on the first invention, the sealed bag is When the pressurized oil is introduced into a plurality of peripheral sealed bags which are arranged at a constant pitch circle spaced from the central portion while being located at the central portion of the mold, the sealed bag located at the central portion At the same time as introducing high-pressure oil into The introduced low pressure oil stationary platen curved to cooperate with the central sealing bags and peripheral sealed bag was to correct. In the third aspect of the invention, which is mainly based on the second aspect, after arranging the central sealed bag so that the diameter of the central sealed bag is larger than the diameter of the peripheral sealed bag, the same hydraulic pressure is introduced into the sealed bag and the central sealed bag is introduced. The bag and the surrounding closed bag cooperated to correct the curved fixed platen. In the fourth invention, a mold mounting plate is superposed on and supported by a fixed platen having tie rods provided at a plurality of corners, and a cylinder hole opened to the mold mounting plate side is provided in the fixed platen. Further, a ram that slidably fits into the cylinder hole is provided, a hermetically sealed bag filled with hydraulic pressure is incorporated, and the mold mounting plate is fixed to the fixed die via the ram by increasing the hydraulic pressure in the sealed bag. According to a fifth aspect of the invention, which is mainly based on the fourth aspect, the bottom of the sealed bag has a flat flat plate shape, the ceiling has an arch shape, and the bottom and the ceiling have the same shape. Were joined with a straight cylindrical portion, and an inlet tube was formed integrally with the closed bag at the bottom, and the inlet tube was connected to a hydraulic pressure source. Further, the sixth invention mainly based on the fourth invention.
In the invention, the bottom part and the ceiling part of the sealed bag are formed into a flat plate shape, and the bottom part and the ceiling part are joined by a straight cylindrical part, and the bottom part has an inlet pipe formed integrally with the sealed bag. Then, the introduction pipe was connected to a hydraulic pressure source. In a seventh invention mainly based on the fourth invention, the closed bag is formed of a stretchable flexible material, and in an eighth invention mainly based on the sixth invention, the closed bag and the introduction pipe are integrally formed. The flexible material which can be extended and contracted is used.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the injection molding die clamping method and apparatus according to the present invention will be described below with reference to FIGS.
This will be described in detail with reference to FIG.

This embodiment shows an example in which the present invention is applied to a horizontal-clamping vertical injection type die-casting machine. FIG. 1 is a partially cutaway front view of the die-casting machine in which the present invention is applied, and FIG. 2 is a plan view of the same die-casting machine. FIG. 3 is a side view of A side in FIG.
FIG. 5 is an explanatory view for correcting a curved fixed mold, FIG. 6 is a front view as viewed from C to C in FIG. 5, and FIG. 7 is another closed bag similar to FIG. FIG. 8 is a front view showing an arrangement state, FIG. 8 is an explanatory diagram for detecting a gap between dies by a sensor, FIG. 9 is a detailed diagram of a hydraulic pipe joint, FIG. 10 is a flowchart for explaining a method for controlling a sealed bag, and FIG. Is a sectional view of a mold clamping cylinder, FIG. 12 is an enlarged view of a main part of a closed bag of the mold clamping cylinder,
FIG. 13 is a sectional view of a mold clamping cylinder similar to the present invention, and FIG.
FIG. 15 is an enlarged view of a main part of the closed bag of the mold clamping cylinder of FIG.
FIG. 16 is an explanatory view for explaining deformation deformation of a ram formed in a semicircular concave shape in accordance with a closed bag having a substantially semispherical shape. FIG. 16 shows a ram formed in a concave shape in conformity with a closed bag having an upper arch shape. FIG. 17 is an explanatory diagram for explaining deformation distortion, and FIG. 17 is an enlarged cross-sectional view taken along line D-D in FIG.

An embodiment of the present invention will be described in detail below with reference to a horizontal clamping vertical injection type injection molding apparatus. In the figure, a fixed platen 2 erected with its base fixed to a machine base 1
At four corners, stepped rod holes 2a shown in FIG. 15 are formed, and one end of a tie rod 3 is inserted into these rod holes 2a. The nut 4 inserted into the hole 2a is screwed. Further, the holding plate 6 fixed to the tip end of the tie rod 3 by a wedge-shaped spanning ring 5 is fixed to the end surface of the tie rod 3 by a bolt 7, whereby the rotation of the tie rod 3 is restricted. It is firmly fixed to the fixed platen 2.

On the other hand, the anti-fixed platen 2 of the machine base 1
A connection plate 8 formed in a substantially square frame shape is provided on the side end.
The legs are slidably fitted to a plate-like rail 1a provided on the machine base 1 and are erected. Each of the rod holes 2a drilled at the four corners of the frame of the connecting plate 8 is provided. The other ends of the tie rods 3 at the four corners extending in the horizontal direction from the fixed platen 2 are inserted via the spanning ring 9, whereby the rotation of the tie rods 3 is restricted, and the tie rods 3 are firmly attached to the connecting plate 8. It is configured to be fixed to.

Reference numeral 10 denotes a movable platen which is located between the fixed platen 2 and the connecting plate 8 and has an upright vertical surface opposed to the vertical surface of the fixed platen 2,
A horizontal member 10a is integrally formed at the lower end thereof, and a guide shoe 11 slidably mounted on the rail 1a is bolted below the horizontal member 10a. By doing so, the movable platen 10 is formed integrally with the guide shoe 11 so as to be able to advance and retreat in the direction toward and away from the fixed platen 2, and the horizontal member 10
The movable platen 10 and the guide bush 11 are adjusted by adjusting the horizontal bolts for fixing the guide plate 11 and the guide bush 11.
The height of the movable platen 10 is finely adjusted by the action of the inclined surfaces 10b and 11a provided in the above.

Further, each of the four tie rods 3 is engaged with a concave hole 10c provided at each of the four corners of the movable platen 10.
A ball screw nut 12 formed in a cylindrical shape is interposed between the concave hole 10 c and the tie rod 3 so as to be rotatable and movable in the axial direction via a needle bearing 13. Movable platen 10 of tie rod 3
A screw groove 3b having a semicircular cross section is provided in substantially half of the side, and a plurality of balls 14 held in a hemispherical concave hole of the ball screw nut 12 are rolled in the screw groove 3b. Is engaged. With this configuration, when the ball screw nut 12 is rotated by a driving device described later, the movable platen 10 advances and retreats along the tie rod 3 by a screw action.

The inner wall surface 13 of the mounting member 13a of the needle bearing 13 which is integrally fixed to the movable platen 10 at the inner end surface in the mold matching direction in the concave hole 10c.
b and tip end 1 of ball screw nut 12 on the mold-matching direction side
Usually, a gap of, for example, about 0.5 mm is provided between the ball screw 2a and the hole 2a so that the ball screw nut 12 can easily rotate.

A movable mold 15 is removably mounted on a vertical plane of the movable platen 10 thus constructed, and a mold mounting plate 45 (to be described later) supported on the fixed platen 2 by being overlapped therewith. In the vertical plane of FIG.
Are detachably attached. By doing this,
When the movable platen 10 is moved forward and backward along the tie rod 3, the movable mold 15 is configured to be matched with the fixed mold 16 or closed.

Therefore, a rotation driving device for the ball screw nut 12 will be described. 3 and FIG.
A substantially square frame-shaped bearing plate 17 having an upright edge is bolted to the vertical end surface of the movable platen 10 on the side of the connecting plate 8. One end of each of the four ball screw nuts 12 is connected to the bearing plate 17 by a bolt. Bearing 18 fitted in a bearing hole of bearing plate 17
Is rotatably supported. Reference numeral 19 denotes a bearing retainer fixed to the bearing 18 by being bolted to the bearing plate 17, and reference numeral 20 denotes a seal member for preventing oil stored in the oil reservoir 21 from leaking.

On the end face of each ball screw nut 12,
Three sprockets 22, 23, 24, 25 are respectively fixed to the center holes by penetrating the respective tie rods 3, and two sprockets 27 having an electromagnetic brake 26 are provided between the upper sprockets 22, 23. But the bearing plate 17
And is fixedly provided on a shaft 28 which is rotatably supported. Further, between the sprockets 22 and 27 and between the sprockets 23 and 27, idle sprockets 29 and 3 are provided.
0 are pivotally mounted on the bearing plate 17, respectively.
A chain 31 is stretched between these sprockets 22, 23, 30, 27, 29.

Further, between the lower sprockets 24 and 25, two sprockets 32 are provided rotatably supported by the bearing plate 17. Also, sprocket 2
Idle sprockets 33 and 34 are pivotally mounted on the bearing plate 17, respectively, between the sprockets 4 and 32 and between the sprockets 25 and 32.
A chain 35 is stretched between 25, 34, 32, and 33.

Further, between the upper and lower sprockets 22, 24, an idle sprocket 36 and a sprocket 37 with an electromagnetic brake are provided supported by the bearing plate 17, and these sprockets 22, 24, 36, 37 are provided.
A single chain 38 is stretched between them. Also,
An idle sprocket 39 and a sprocket 41 with an electromagnetic brake 40 are provided between the upper and lower sprockets 23 and 25.
Are supported by the bearing plate 17, and a single chain 42 is stretched between the sprockets 23, 25, 41, and 39. Thus, when the movable platen 10 is moved by the movable cylinder 43 to be described later to open and close the mold, the ball screw nut 12 rotates while moving in the mold opening and closing direction.
Since 2, 23, 24, and 25 rotate simultaneously, the movable platen 10 moves smoothly. By stopping the operation of the moving cylinder 43, the electromagnetic brakes 26, 40
By operating the same, the four ball screw nuts 12 are suddenly stopped at the same time.

A movable cylinder 43 for the movable platen 10 is fixed to the upper end of one side of the fixed platen 2 and the lower end of the other side, respectively. The working end of the piston rod 44 is connected to the bearing plate. 17 are fixed to both side surfaces. By doing so, the bearing plate 17 and the movable platen 10 advance and retreat by the action of the piston rod 44 when the mold is set and the mold is opened, and are provided between the bearing plate 17 and the movable platen 10 by the retreat of the piston rod 44 when the mold is clamped. The bearing plate 17 is configured to be brought into pressure contact with the movable platen 10 by eliminating a slight gap.

In this apparatus, a mold clamping cylinder for correcting the curvature of the fixed mold 16 during mold clamping is provided on the fixed platen 2 side. That is, on the vertical plane of the fixed platen 2, a square plate-shaped mold mounting plate 45 in which rod holes at four corners are slidably fitted to the tie rods 3 is overlapped. In the surface facing the plate 45, there are provided three cylinder recesses 46, each of which is a circular hole centered at a point at which a circle around the center of this facing surface is equally divided into three in the circumferential direction.
Are provided to open to the mold mounting plate 45 side.

As shown in FIGS. 11 and 12, a mold clamping cylinder device generally designated by reference numeral 50 is embedded in each of the cylinder holes 46. As shown in FIG. 11, the mold clamping cylinder device 50 includes a cylindrical ram cylinder 47 fitted into a cylinder hole 46 and bolted, a bottom plate 49 at a lower end of an inner hole of the ram cylinder 47, and a ram cylinder 47. And a ram 48 slidably fitted in the inner hole of 47.
The lower part of the ram 48 has an arch-shaped concave portion 48a so as to be in contact with the sealing bag 73.

The closed bag 73 has a flat bottom 73a.
And an arched ceiling portion 73b, and the bottom portion 73a and the ceiling portion 73b are joined by a straight cylindrical portion 73c. Pressurized oil is introduced into the inside of the closed bag 73 through a hydraulic pressure inlet 76 formed at the center of the bottom 73a of the closed bag 73 to inflate the closed bag 73 and to apply a pressing force F to the ram 48.
And the curvature of the fixed mold 16 is corrected so that the fixed mold 1
The correction force is applied so that 6 is straightened.

The outer peripheral surface of the sealed bag 73 and the ram 48
A high-viscosity oil, such as grease, can be applied between the inner peripheral surfaces by means (not shown).
The pressure oil F is introduced into the inside of the ram 3 and the sealing bag 73 is inflated to transmit the pressing force F to the ram 48 smoothly. In addition, as the sealed bag 73 used in this example, for example, nitrile rubber, acrylic rubber, silicone rubber,
A flexible material having excellent oil resistance, such as fluoro rubber, is preferable. The thickness varies depending on the diameter of the ram 48, but is preferably, for example, 1 to 5 mm. In this embodiment, since the pressurized oil is sealed in the sealed bag 73, the hydraulic pressure does not leak even if the fixed mold 16 is bent at the time of mold clamping. There is no need to provide a plurality of O-rings or labyrinth grooves between the rams 29 for preventing oil leakage.

FIGS. 13 and 14 show another embodiment similar to the mold clamping cylinder shown in FIG. 11. Similar to the sealing bag 73 shown in FIG. 11, the sealing bag 73 has a cylindrical portion having a cylindrical body. 73c, a flat bottom 73a and a flat ceiling 73b. On the other hand, the bottom plate 49 is formed in a flat plate shape so as to be in contact with the closed bag 73. Further, a hydraulic pressure inlet 76 is provided at the bottom 73a of the sealed bag 73, and the same effect as that of the mold clamping cylinder device 50 of FIG. 11 can be obtained.

In the present invention, the desirable shape of the ram 48 will be described with reference to FIG. 16. The ceiling 73 b of the sealing bag 73 has a convex arch shape. Since the lower end of the contacting ram 48 has a concave arch shape, the periphery of the lower end of the ram 48 has a shape having a slight protrusion 70B. That is, the ceiling portion 73b of the sealing bag 73 has a ratio r / r between the radius of curvature R of the arch shape and the radius r of the bottom portion 73a of the sealing bag 73.
R is set to 1/2, and 21
When a hydraulic pressure of 0 kg / cm2 is introduced, the lower peripheral portion 7 of the ram 48
0B causes a radial amount of deflection Δr as shown by a two-dot chain line in FIG. However, the ratio of the amount of flexure Δr to the radius r as the basic dimension, that is, Δr / r, is negligibly small. This means that the expansion of the sealing bag 73 causes the lower end peripheral portion 70B of the ram 48 to flex, Practical studies have shown that when the ram 48 moves inside the ram cylinder 47 toward the fixed platen 2, it does not move while sliding on the inner wall surface of the ram cylinder 47.

However, in the process of examining the problem, a sealed bag 73 having a shape closer to a semi-spherical shape is easy to mold, and even if high-pressure oil is further introduced into the sealed bag 73 and expansion is repeated. Since the sealing bag 73 is less likely to be damaged by rupture and the like, and the safety factor in strength is increased,
For example, it is naturally conceivable to use a sealed bag 73 having a structure as shown in FIG. A verification test was performed using the ram 48 and the sealed bag 73 having such a structure.

However, when the shape of the sealed bag 73 is made substantially semicircular, the ceiling 73b of the sealed bag 73 has a radius of curvature R (= r) smaller than the arch shape shown in FIG.
The ratio r / R with respect to the radius r (inner dimension) of the bottom 73a of the No. 3 is set to 1/1, and 210 kg
/ cm2 hydraulic pressure, the lower part of the ram 48
Since 0A protrudes largely toward the closed bag 73, a large amount of bending Δ in the radial direction as shown by a two-dot chain line in FIG.
r. The ratio of the amount of flexure Δr to the radius r as the basic dimension, that is, the value of Δr / r is too large to be neglected. Practical investigations have shown that when moving to the fixed platen 2 side, the movement is achieved in a state of being in strong sliding contact with the inner wall surface of the ram cylinder 47. As a result, the pressing force on the ram 48 due to the oil pressure is greatly reduced, and a sufficient pressing effect cannot be exerted.

In view of the above, the ram 48 having an allowable shape is different from the ram 48 having the shape shown in FIG.
6, it is considered to be located between the ram 48 having the shape shown in FIG. 6. Therefore, when the experiment was repeated, the curvature radius R of the arch shape of the ceiling 73 b of the sealed bag 73 and the bottom 73 a of the bottom 73 a of the sealed bag 73 were changed. The ratio r / R to the radius r is 1 /
It has been found from practical investigations that it is permissible up to around 1.5.

Next, using the sealed bag 73 of the present invention, FIG.
The curvature between the movable mold 15 and the fixed mold 16 as shown in FIG.
The control for eliminating the gap between 16 will be described. First, a gap sensor 82 is provided at a position having the same surface as the parting surface of the fixed mold 16. The sealing bag 73 and the gap sensor 82 are disposed integrally on the front and back, and the gap S obtained by the gap sensor 82 is transmitted to the sealing bag 73 located on the back of the gap sensor 82 to transmit information on the gap S. Gap S
Is applied to the back surface of the fixed die 16 to correct the curved fixed die 16 so as to be in a vertical state.

As shown in FIG. 8, on the front surface of the gap sensor 82, a flat heat-resistant insulator 84 made of ceramics or silicone rubber is provided. Using an overcurrent sensor as the gap sensor 82, the two dies 15, 1
The principle is to measure the gap S between the six, but this principle is to pass a high frequency overcurrent to the coil in the overcurrent sensor,
The amount of change in the reactance caused by the contact of the conductor of the movable mold 15 is changed to the gap S, and then displayed on the indicator 86 shown in FIG. Of course, by detecting the amount of curvature of the surface of the fixed mold 16 using, for example, an ultrasonic wave, a photoelectric tube, a piezoelectric element, or the like, and controlling the amount of protrusion or the like due to the expansion of the sealed bag 73 according to the detected amount, The fixed mold 16 may not be changed.

Further, the hydraulic pressure of the hydraulic supply pump 88 can be changed according to the amount of change in the gap S. The pressure oil from the hydraulic feed pump 88 is supplied to the sealed bag 73 and
Due to the expansion of 3, the back surface of the fixed mold 16 is pressed toward the movable mold 15 to correct the curved fixed mold 16 to be vertical. Reference numeral 100 indicates an oil tank.

In particular, in the present invention, the largest pressure is applied to the curved fixed mold 16 so that the pressure oil supplied to the closed bag 73 can be changed according to the gap between the two molds 15 and 16 ( In step S1), a high oil pressure is supplied to the central hermetic bag 73A located at the center of the
Is further expanded, and the fixed mold 16 having a gap (S2) between the fixed molds 16 at a position slightly apart from the center.
Are arranged at equal pitches, for example. By doing so, the most gap (curvature)
The hydraulic feed pump 88 is located at the center of the large fixed die 16.
From the central sealed bag 73
Since the clearance value is smaller than the central portion of the fixed mold 16, the peripheral sealing bag 73 </ b> B located at a position away from A is supplied with a slightly smaller hydraulic pressure than the central sealing bag 73 </ b> A. It has been found that the hydraulic pressure of the fixed mold 16 can be efficiently corrected according to the gap value.

In FIG. 6, a plurality of closed bags 73 having the same diameter are arranged, and a large number of hydraulic pressures corresponding to the gaps are provided so that the hydraulic pressure can be changed according to the gaps between the curved molds 15 and 16. Although the feed pump 88 is provided, the present invention is not limited to this. For example, as shown in FIG. You may make it send to the bag 73B simultaneously. In this case, the correction force for correcting the curved stationary mold 16 is increased by increasing the diameter of the central sealing bag 73A so that the largest correcting force acts on the central sealing bag 73A, thereby increasing the pressure receiving area. The force can be increased, and the peripheral sealing bag 73B is made smaller than the central sealing bag 73A, so that the pressure receiving area is reduced to reduce the correction force.

FIG. 9 shows a closed bag 7 at the end of the fixed platen 2.
3 is an enlarged cross-sectional view of the hydraulic pressure introducing section of FIG.
A hydraulic introduction flange 90 having a hydraulic introduction port 76 on the end face of the stationary mold 16 opposite to the stationary platen 2 is
Are mounted by bolts so as to fit into recesses formed in the end surfaces of the rims. A truncated conical portion 91 is provided on the sealing bag 73 side of the hydraulic pressure introducing flange 90. Even if high-pressure oil leaks, the hydraulic pressure gradually loses energy due to pressure loss while passing through the plurality of labyrinth grooves 92. The pressure is low so that no oil leaks to the outside.

A bottom portion 73a of the sealed bag 73 is extended and attached to the inner wall surface of the hydraulic pressure inlet 76 to form a tube portion 73d forming a part of the sealed bag 73. The hydraulic introduction side end of the fixed platen 2 has an enlarged diameter along with the truncated conical portion 91 of the hydraulic introduction flange 90, and when the hydraulic introduction flange 90 is attached to the fixed platen 2, the labyrinth The groove 92 is in contact with or close to the tube portion 73d. The hydraulic pressure introducing flange 90 is provided with a conduit connecting portion 94 so that a conduit for supplying hydraulic pressure from the hydraulic supply pump 88 to the closed bag 73 is connected thereto. Reference numeral 96 indicates a packing.

In FIG. 4, the reference numeral 53 designates both molds 15,
16. A vertical casting type injection device which is disposed on the outside of the injection sleeve 16 so as to be tiltable, and has a plunger tip which moves up and down in an injection sleeve (not shown) by hydraulic pressure, and melts the metal supplied into the injection sleeve by the plunger tip. It is configured that the molten metal is injected into the cavities formed in the dies 15 and 16 by being pushed forward. An extruding cylinder 54 is embedded in the movable platen 10 in FIG.
The product is extruded from the cavity of the opened movable mold 15 by solidification of the molten metal. In this embodiment, the horizontal clamping vertical injection type injection molding apparatus has been described as a representative example. However, the present invention is not limited thereto, and the horizontal clamping horizontal injection type injection molding apparatus and the vertical clamping vertical injection type injection molding apparatus are not limited thereto. It can also be applied to molding equipment.

The operation of the die casting machine configured as described above will be described.

From the mold open state shown in FIG.
When the bearing plate 17 and the movable platen 10 are moved by operating the moving cylinder 43 for use, the ball screw nut 12 rotates. At this time, the four ball screw nuts 12 on which the chains 31, 35, 38, and 42 are stretched rotate synchronously. When the ball screw nut 12 rotates, the ball screw nut 12 moves on the stationary tie rod 3 with the bearing plate 17 by the screw action, and the movable die 1
When 5 contacts the fixed mold 16, the operation of the moving cylinder 43 is stopped, and the electromagnetic brake 26 is operated.
The movable mold 15 stops suddenly, and mold matching is performed. At this time, since the oil has been drained from the head end chamber of the movable cylinder 43, the piston rod 44 moves backward with the movement of the movable platen 10.

Thus, the movable mold 15 is fixed to the fixed mold 1.
6, the piston rod 44
The movable platen 10 incorporating the ball screw nut 12 slightly moves rearward with respect to the bearing plate 17 to which the working end is fixed. The movable platen 10 is pressed relatively rearward by strong mold matching, and the inner wall surface 1 of the mounting member 13a to which the needle bearing 13 is mounted is mounted.
3b is pressed against the tip end surface 12a of the ball screw nut 12 whose rotation is restricted by the action of the electromagnetic brake 26,
Tip surface 12a of ball screw nut 12 and mounting member 13a
A slight gap formed between the movable die 15 and the movable platen 10 is eliminated by the ball screw device, and the movement of the movable platen 10 is braked without play. Further, since the tie rod 3 is fixed at both ends via the spanning rings 5 and 9, the tie rod 3 is not twisted.

With reference to FIG. 10, a description will be given of a control method for introducing pressurized oil from the hydraulic pressure introduction port 76 into the closed bag 73 after the molds are matched. First, FIG.
In the case of (1), the central sealed bag 73A and the peripheral sealed bag 73B
This shows the case where the diameter of is changed. Moving mold 15 and fixed mold 1
When the mold 6 is matched or when the molten metal is injected into the cavity, the gap between the two dies 15 and 16 is detected by the gap sensor 8.
If the measured gap S is within the allowable range, the hydraulic pressure introduced from the hydraulic pressure supply pump 88 into the sealed bag 73 presses the back surface of the fixed mold 16 to a level that maintains the current state. Only things are supplied.

However, when the fixed mold 16 is greatly curved and the measured gap S deviates from an allowable value, the hydraulic pressure increased so that the curved fixed mold 16 becomes vertical is applied to the central sealed bag. 73A and the peripheral sealed bag 73B are simultaneously introduced,
The airtight bag 73 further expands, and the lower portion and the side surface of the airtight bag 73 are restricted from expanding by the ram cylinder 47 and the bottom plate 49, respectively, so that the degree of freedom by expansion only above the airtight bag 73 is secured. The sealing bag 73 is provided in the recess 4 of the ram 48.
8a, the pressing force F by the increased hydraulic pressure is transmitted to the ram 48 side to advance the ram 48 and straighten the curved fixed mold 16 via the mold mounting plate 45. The correction is performed in this manner, and the mold is slightly moved with the fixed mold 16 against the correcting force due to the movement of the ram 47 to perform mold clamping.

At this time, the correcting force W corresponding to the pressing force according to the area ratio is applied to the central sealing bag 73A having a large diameter, and the correcting force W1 smaller than the central sealing bag 73A is applied to the peripheral sealing bag 73B.
Is added. In this case, the correcting forces W and W1 correspond to the curved gap between the fixed mold 16 and the movable mold 15, respectively. Then, when the clearance is returned to the original state by the correcting forces W and W1 applied from the outside by the clearance sensor 82, the hydraulic pressure is held.

At the time of this mold clamping, since the back side of the mold mounting plate 45 curved in an O-shape is pressed by the movement of the ram 48, the movable platen 10 is strongly braked by both the electromagnetic brake 26 and the ball screw device. As a result, the movable mold 15 and the fixed mold 16 do not bend, and there is no gap in the joint surface between the movable mold 15 and the fixed mold 16.

After the mold has been clamped in this way, the molten metal is injected into the injection sleeve and the plunger tip is advanced in the injection sleeve by hydraulic pressure, whereby the molten metal is injected into the mold cavity. At the time of this injection, no gap is formed in the joining surface between the movable mold 15 and the fixed mold 16 as described above, and even when the molten metal is injected into the cavity, both molds 15 and
Since the molten metal does not erupt from the joint surface of No. 16, the safety is improved and a cast product having an accurate shape and dimensions can be obtained reliably and easily.

After the molten metal injected into the mold cavity is solidified, the oil in the cylinder hole 46 is drained, the braking by the electromagnetic brake 26 is released, and the movable cylinder 43 is operated to open the mold. At this time, the mold is opened smoothly by the operation of the ball screw device. Since the product obtained by solidification of the molten metal is held and moved by the movable mold 15, the product is extruded from the mold cavity by the extrusion cylinder 54, and is taken out of the machine by the product take-out device. The casting cycle is completed.

Next, FIG. 10B shows an embodiment in which the diameter of the central sealed bag 73A and the diameter of the peripheral sealed bag 73B are the same. In this case, it is desirable to introduce hydraulic pressures having different pressures from a hydraulic supply pump 88 as shown in FIG. 5 so that a large correction force W acts on the above-mentioned central sealed bag 73A. That is, a hydraulic pressure higher than that of the peripheral sealing bag 73B is introduced. At the same time, a slightly lower hydraulic pressure is introduced from the hydraulic supply pump 88 so that a correction force W1 smaller than the central sealed bag 73A is applied to the peripheral sealed bag 73B. As described above, the correction forces W and W1 for pressing the back surface of the fixed mold 16 are in accordance with the gap value obtained by the gap sensor 82. The hydraulic pressure is maintained when the gap returns to the original state by the correction forces W and W1 applied from the outside.

In this embodiment, the case where five mold clamping cylinders 50 are provided is illustrated in FIGS. 4, 6 and 7, but the number is not limited, and the gap value and the size of the mold are not limited. It is desirable to arrange five or more pieces so that the curvature of the mold can be corrected according to the degree. Further, in this embodiment, an example is shown in which the airtight bag 73 is incorporated in a die casting machine. However, the present invention can be similarly applied to an injection molding machine for plastics, and the same effects can be obtained.

[0055]

As apparent from the above description, the present invention has the following advantages. In other words, pressure oil is introduced into the corresponding sealed bag according to the degree of curvature of the mold, that is, the gap value between the molds, so that smoothness can be corrected with optimal pressure oil, and smooth correction is easy. Can be. Since the pressure receiving area is made different by changing the diameter of the central sealed bag and the peripheral sealed bag, and the same pressure is supplied to the sealed bag, the configuration of the hydraulic pressure supply device is simplified. Since the sealing bag is formed in an arch shape, the propagation of the pressing force by the hydraulic pressure is smooth, so that the sealing bag is not locally damaged and can be used for a long time.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a die casting machine embodying the present invention.

FIG. 2 is a plan view of a die casting machine embodying the present invention.

FIG. 3 is a side view of A side in FIG. 1;

FIG. 4 is a side view on the B side of FIG. 1;

FIG. 5 is an explanatory diagram for correcting a curved fixed mold.

FIG. 6 is a front view as seen from DD in FIG. 5;

FIG. 7 is a front view showing an arrangement state of another sealed bag similar to FIG. 6;

FIG. 8 is an explanatory diagram for detecting a gap between molds by a sensor.

FIG. 9 is a detailed view of a hydraulic pipe joint.

FIG. 10 is a flowchart illustrating a method for controlling a sealed bag.

FIG. 11 is a sectional view of a mold clamping cylinder.

FIG. 12 is an enlarged view of a main part of a sealed bag of a mold clamping cylinder.

FIG. 13 is a sectional view of a mold clamping cylinder similar to the present invention.

FIG. 14 is an enlarged view of a main part of a closed bag of the mold closing cylinder of FIG. 7;

FIG. 15 is an explanatory diagram for explaining the amount of bending exerted on the ram shape when the closed bag is inflated when the closed bag is formed into a semi-spherical shape.

FIG. 16 is an explanatory diagram for explaining the amount of deflection exerted on the ram shape when the airtight bag is inflated when the airtight bag is formed into a dome shape.

17 is an enlarged cross-sectional view taken along the line CC in FIG. 3;

FIG. 18 is a sectional view of a conventional mold clamping cylinder.

FIG. 19 is a sectional view of a conventional sealed bag.

[Explanation of symbols]

 2 Fixed Platen 3 Tie Rod 10 Movable Platen 15 Movable Die 16 Fixed Die 26 Electromagnetic Brake 40 Electromagnetic Brake 43 Moving Cylinder 45 Die Mounting Plate 46 Cylinder Hole 47 Ram Cylinder 48 Ram 48 a Recess 49 Bottom Plate 50 Mold Clamping Cylinder 53 Vertical Casting Built-in injection device 54 Pressing cylinders 70A, 70B Projecting portion 73 Sealing bag 73a Bottom portion 73b Ceiling portion 73c Cylindrical portion 73d Tube portion 73A Central sealing bag 73B Peripheral sealing bag 74 Sealing bag pressing member 75 Edge bottom portion 76 Hydraulic inlet 80 Parting Surface 82 Gap sensor 84 Heat resistant insulator 86 Indicator 88 Hydraulic feed pump 90 Hydraulic introduction flange 91 Truncated cone 92 Labyrinth groove 94 Conduit joint

Claims (8)

[Claims] A plurality of hermetic bags for correcting a fixed mold curved by mold clamping are provided so as to be in contact with a mold facing surface in a fixed platen, and a plurality of closed bags are provided between the fixed mold and the movable mold. A gap sensor is arranged at a position having the same surface as the fixed mold parting surface to measure a gap value between both curved molds, and is supplied to a plurality of the sealed bags according to the magnitude of the gap value. A pressure oil to be applied is changed. 2. The sealing bag according to claim 1, wherein said sealing bag is located at a central portion of a fixed mold, and a plurality of peripheral sealing bags which are spaced apart from each other on a fixed pitch circle separated from said central portion. At the time of introducing the oil, at the same time as introducing high-pressure oil to the sealing bag located in the central portion, the central sealing bag and the peripheral sealing bag by introducing a slightly lower pressure oil than the central sealing bag to the peripheral sealing bag. A mold clamping method for injection molding, wherein the curved fixed platen is corrected by cooperating with the above. 3. The airtight bag according to claim 2, wherein the diameter of the central airtight bag is larger than the diameter of the peripheral airtight bag, and then the same oil pressure is introduced into the airtight bag so that the central airtight bag and the peripheral airtight bag are arranged. A mold clamping method for injection molding, wherein a curved fixed platen is corrected in cooperation with a sealed bag. 4. A fixed platen having tie rods provided at a plurality of corners, a mold mounting plate is superimposed and supported, and a cylinder hole opened to the mold mounting plate side is provided in the fixed platen. Further, a ram that slidably fits into the cylinder hole is provided, a sealed bag filled with hydraulic pressure is incorporated, and the mold mounting plate is fixed to the fixed mold side via the ram by increasing the hydraulic pressure in the sealed bag. A mold clamping device for injection molding, characterized in that a pressing force for pressing the mold can be added. 5. The closed bag according to claim 4, wherein the bottom portion has a flat plate shape, the ceiling portion has an arch shape, and the bottom portion and the ceiling portion are joined by a straight cylindrical portion to be sealed to the bottom portion. An injection-molding mold clamping device, comprising an inlet tube formed integrally with a bag, wherein the inlet tube communicates with a hydraulic source. 6. The closed bag according to claim 4, wherein the bottom and the ceiling are flat and flat, and the bottom and the ceiling are joined by a straight cylindrical portion, and formed integrally with the closed bag at the bottom. An injection-molding mold clamping device, comprising: 7. A mold clamping device for injection molding, characterized in that the sealed bag according to claim 4 is formed of a flexible material that can expand and contract. 8. A mold clamping device for injection molding, characterized by using a stretchable flexible material integrally formed with the sealed bag and the introduction tube according to claim 6.