JP5604915B2 - Clamping device - Google Patents

Description

  The present invention relates to a mold clamping device used for die casting machines and injection molding machines for molding aluminum products and plastic products.

  In die-casting machines and injection molding machines, high-temperature molten aluminum and resin are filled into the cavity (molded product shape), which is the space of the closed mold, at high speed and high pressure by an injection device, and then cooled and solidified. Later, the mold is opened and the molded product is taken out for production. For this reason, the mold clamping device requires a function that can open and close the mold at high speed and can apply a large mold clamping force to the mold so that the mold does not open and burr due to high pressure during filling. Is done. So far, many types of mold clamping devices, such as a toggle type, a direct pressure type, and a composite type have been devised and used. In these mold clamping apparatuses, a fixed mold and a movable mold of a movable plate are attached to a fixed plate, and four tie bars are passed through the four corners of each plate, and are connected to the respective plates via tie bar nuts or the like. The mold clamping force generator applies a large mold clamping force to the mold, and the reaction force generated at that time is received by the tie bar.

However, if a mold is directly attached to the fixed plate or movable plate and a clamping force is applied, each plate will be deformed (flexed), and the center part of the mold parting surface where the melt pressure is high In this case, it is difficult to generate a high surface pressure, and burrs are generated when the pressure of the melt is lost.
In recent years, in order to cope with these problems, in the toggle type mold clamping device described in Patent Document 1, the staple connected to the link mechanism is tapered, and by connecting only to the center of the moving platen holding the movable mold, A high surface pressure is generated at the center of the mold.
Further, in Patent Document 2, a taper frustum-like or columnar connecting portion is provided on the opposite side of the die mounting plate toward the force receiving plate so that the clamping force is concentrated on the central portion of the die. Yes.

Japanese Patent No. 3591908 JP 2008-100504 A

  However, in the mechanisms disclosed in Patent Document 1 and Patent Document 2, the angle of the tapered portion is not defined. If the angle between the gradient portion and the plane portion is large, the contact portion (the gradient surface and the plane intersect each other). In this structure, a large contact surface pressure (pressing force) is generated at the corners, and the moving platen and the force receiving plate are plastically deformed and may be damaged.

In order to solve the above problems, the invention of the present application
A machine base, a fixed plate that is fixedly mounted on the machine base and holds a fixed mold, a fixed platen that is mounted on the side opposite to the mold of the fixed plate, and can slide on the machine base in the mold opening / closing direction A movable plate that is placed on the movable plate and holds the movable mold, a movable platen that is slidably mounted in the mold opening and closing direction on the opposite mold side of the movable plate, four tie bars that receive a clamping force, and a fixed platen The tie bar and piston are integrated into a mold clamping cylinder that generates a clamping force, the movable platen is equipped with a half nut that can be disengaged from the tie bar, and the movable plate and the movable platen are driven to open and close. A mold opening and closing device, and a mold clamping device comprising: a fixed platen that is in contact with the fixed plate; and a movable platen that is in contact with the movable plate. The surface, the central portion is the peripheral portion in plan has become a conical or pyramidal slope surface shape,
When the fixed platen and the movable platen are bent and deformed by receiving the maximum clamping force, the corners of the boundary line between the flat surface and the gradient surface shape become contact portions that contact the fixed plate and the movable plate, and the fixed plate and the movable platen are movable. The angle on both sides of the contact portion with the plate is substantially equal to the angle θ in the diagonal direction of the tie bar,
When the mold clamping force is not received, the mold clamping device is formed so that the angle between the inclined surface portion and the plane portion of the fixed plate and the movable plate is 2θ ° in the diagonal direction of the tie bar .

The mold clamping device of the present invention exhibits the following effects.
(1) Since the peak surface pressure at the contact portion is reduced, it is possible to eliminate damage to the molding machine due to the depression and deformation of the contact portion.
(2) Since the surface pressure can be widely dispersed in the contact portion, the surface pressure acting on the mold parting surface can be widely equalized.
(3) The thickness of the fixed plate and the movable plate can be reduced, and the weight of the machine can be reduced and the cost can be reduced.

It is an Example of the mold-clamping apparatus which concerns on this invention, and shows the state which the metal mold | die is open. In the embodiment of FIG. 1, the mold is closed and a clamping force is applied. It is a figure when it sees from the arrow A in FIG. 1, and shows the Example whose surrounding part of a stationary platen is cone shape. It is a figure when it sees from the arrow A in FIG. 1, and shows the Example whose surrounding part of a stationary platen is a quadrangular pyramid shape. It is a figure when it sees from the arrow A in FIG. 1, and shows the Example whose surrounding part of a stationary platen is octagonal pyramid shape. The contact state and the contact pressure distribution of the contact portion (corner portion) in the present invention are shown. The contact state and surface pressure distribution of a contact part in a prior art are shown.

  Embodiments according to the present invention will be described below with reference to the drawings.

  An embodiment of a mold clamping device will be described with reference to FIGS.

  FIG. 1 shows a state in which the mold clamping device is open. On the machine base 15, the fixed plate 7 is fixedly placed via a fixed key 16, and the fixed mold 1 is attached. The stationary platen 4 is placed on the lower part of the stationary plate 7 or on the machine base 15 in an unconstrained state. Further, the surface of the fixed platen 4 that comes into contact with the fixed plate 7 is flattened at the central portion, and the peripheral portion thereof is subjected to a gradient processing with an angle of 2θ °, thus forming a conical or pyramidal shape. . Further, the fixing plate 7 is not separated from the fixing platen 4 by the fixing bolt 20. By mounting in this way, even when the mold clamping force is applied to the fixed platen 4 and deformed, the deformation does not affect the fixed plate 7. On the other hand, the surface of the fixed plate 7 on the side in contact with the fixed platen 4 is a flat surface. The stationary platen 4 has a built-in clamping cylinder, and the tie bar 9 and the piston 10 are integrally coupled. Further, a rod 11 is coupled to the piston 10, and a mold clamping oil chamber 10 a and a mold release oil chamber 10 b are formed by an inner portion of the fixed platen 4. When a high pressure hydraulic oil is supplied to the clamping oil chamber 10a of the clamping cylinder by a hydraulic device and piping (not shown), a clamping force is generated, and when hydraulic pressure is supplied to the releasing oil chamber 10b, the releasing force (strong type) Open force). An injection hole 13 is provided in the center of the fixed platen 4 and the fixed plate 7. An injection device (not shown) is arranged on the right side of the mold clamping device, and a tip portion of the injection device can be inserted into the injection hole 13 and can be connected to an inflow port communicating with a cavity in the mold.

A slide rail 25 is attached on the machine base 15, and the movable plate 8 is placed integrally with the movable table 24 via the slide block 26. The movable mold 2 is attached to the movable plate 8. Since the slide block 26 is connected to the slide rail 25 via balls or rollers, the slide block 26 can be slid with little frictional resistance. The movable platen 5 is placed on the movable table 24 without being constrained, and is attached by a fixing bolt 20 so as not to be separated from the movable platen 8. Further, the surface of the movable platen 5 on the side in contact with the movable plate 8 is processed with a flat surface at the center and a gradient of 2θ ° at the peripheral portion, like the fixed platen 4. Further, the movable platen 5 has a tie bar 9 passing therethrough and a half nut 12 that is divided into two. The half plate 12 is attached to the movable platen 5 so that the movable platen 5 is engaged with the engaging portion 9a of the tie bar 9 by being opened and closed. Joining and leaving is possible. The tie bar engaging portion 9a is provided with a ring-shaped or screw-shaped groove, and meshing teeth are formed. By engaging with the teeth formed inside the half nut 12, the tie bar 9 and the half nut 12 are Can be engaged. The half nut 12 can be opened and closed by a hydraulic cylinder or a combination of a motor and a ball screw.
Further, the movable platen 5 is provided with an unillustrated extrusion device, and the molded product can be detached from the movable mold 2.

  Since the mold opening / closing device is connected between the movable base 24 and the machine base 15, the movable plate 8, the movable platen 5 and the like can be slidably driven in the mold opening / closing direction. A nut mounting block 33 is fixed to the lower side of the movable base 24, and a mold opening / closing ball screw nut 32 is mounted. The mold opening / closing ball screw shaft 31 screwed with the mold opening / closing ball screw nut 32 is supported by the screw shaft support base 38 in a state in which it is rotatable through a bearing but is restrained in the axial direction. The screw shaft support base 38 is fixed to the machine base 16. One end of the mold opening / closing ball screw shaft 31 is connected to the rotating shaft of the mold opening / closing servomotor 30 by a coupling 37, and the other end is rotatably supported by a screw shaft support base 34. In addition, the brake 35 is connected. The brake 35 is attached to the screw shaft support 34, and is provided to prevent the movable part from moving when an emergency stop is caused during an emergency or when the machine is stopped.

  FIG. 2 shows a state in which the mold is closed and a clamping force is applied, and the half nut 9 a is closed and engaged with the tie bar 9. Further, the platen and the tie bar 9 are bent (deformed) by the mold clamping force. At this time, the fixed platen gradient surface 4b around the fixed platen 4 has an angle of θ ° with the fixed plate 7 due to the deformation, and the fixed platen flat surface portion 4a is also bent due to the deformation. Is also θ °. The same applies to the movable platen 5 side. The 2θ ° of the gradient processing applied to the fixed platen 4 and the movable platen 5 can be calculated by previously analyzing the deformation angle of each platen using CAE such as a finite element method at the design stage. It is preferable to calculate 2θ ° in a state where the maximum mold clamping force that can be exhibited by the mold clamping device is generated.

3 to 5 are views when the fixed platen 4 is viewed from the arrow A in FIG. 1, and shows the state of the surface on the fixed plate 7 side.
The stationary platen 4 is placed on the machine base 15 without being restrained via the lower part of the stationary plate 7 or the like. Four tie bars 9 are attached to the four corners via a clamping cylinder. An injection hole 13 is opened at the center, and the periphery thereof is a flat fixed platen plane 4a. When not receiving the clamping force, the fixing platen plane 4a and the fixing plate 7 are in light contact with each other by the fixing bolt 20. Further, the periphery of the fixed platen plane 4a is a conical fixed platen gradient surface 4b. A boundary line (a crossing portion of the surfaces) between the fixed platen plane 4a and the fixed platen gradient surface 4b is a corner, and becomes a contact portion that comes into contact with the fixed plate 7 when deformed by receiving a clamping force. The fixed plate 7 receives a clamping force from a narrow range of the contact portion, but the force spreads and is transmitted to the fixed mold 1 depending on the thickness of the fixed plate 7, and the surface pressure becomes uniform on the mold parting surface. In consideration of the fact that the mold clamping force is applied from the four tie bars 9, the gradient angle of 2θ ° is desirably an angle when the diagonal line with the largest deformation is viewed from the side.
The surface of the movable platen 5 on the movable side that is in contact with the movable plate 8 is also processed into the same shape, and a uniform surface pressure is applied to the mold parting surface by the same action and effect.

  FIG. 6 is an enlarged view of a contact portion between the fixed platen 4 and the fixed plate 7 (corner portion of the fixed platen 4). The angle between the fixed platen gradient surface 4b and the flat portion of the fixed plate 7 is 2θ °. Since the deformation amount of the fixed platen 4 due to the mold clamping force is small, the angle is as small as 2θ °. Therefore, the apex angle of the corner of the fixed platen 4 is an obtuse angle close to 180 °. When the clamping force is received, the fixed platen 4 is deformed as shown in the right figure. The angle between the surfaces generated on the upper side and the lower side of the contact portion is substantially the same θ °, and the surface pressure of the contact portion is generated in a vertically symmetrical manner. The fixed plate 7 is elastically deformed by the corners of the fixed platen 4 and the surface pressure is generated in a wide range. As the surface pressure portion becomes wider, the peak surface pressure decreases, so that a large surface pressure that causes plastic deformation does not occur in the peak surface pressure portion, and the contact portion does not collapse. Moreover, since the mold clamping force can be widely diffused, the mold clamping force can be uniformly transmitted to the mold even if the fixing plate 7 is thin.

  On the other hand, FIG. 7 is a diagram of the contact portion in the prior art, and since the apex angle between the gradient portion and the flat portion is small, the contact range (surface pressure distribution range) at the time of mold clamping is narrow, and a large peak surface pressure is present. You can see that it has occurred. This causes plastic deformation and damages the platen and the like, leading to a failure of the molding machine.

FIG. 4 shows another embodiment, in which the fixed platen gradient surface 4b is processed on a quadrangular pyramid, and the same effects as those of the embodiment of FIG. 3 are achieved.
FIG. 5 is still another embodiment, and the fixed platen gradient surface 4b is processed on an octagonal pyramid.

Next, the molding operation by the mold clamping device of the present embodiment will be described.
First, in the mold open state of FIG. 1, the half nut 12 is open and in a detached state from the tie bar 9. After a release signal is sent from the control device (not shown) to the brake 35, a rotation command signal is sent to the mold opening / closing servo motor 30, and the mold opening / closing ball screw shaft 31 is rotated. The ball screw nut 32, the nut mounting block 33, the movable base 24, the movable platen 5, the movable plate 8, and the movable mold 2 move in the closing direction (right direction in the figure). When the movable mold 2 touches the fixed mold 1, the mold opening / closing servomotor 30 stops and enters a free state. Next, the position of the movable platen 5 is detected from the encoder of the servo motor 30 for opening and closing the mold, and if there is no positional relationship in which the teeth of the tie bar engaging portion 9a and the teeth of the engaging portion of the half nut 12 are engaged, Hydraulic oil is appropriately supplied to the tightening cylinder, and the tie bar 9 is moved to adjust the teeth to mesh with each other. When the thickness of the mold is known in advance, the position of the tie bar 9 may be adjusted before the mold closing operation.

  Subsequently, the half nut 12 is closed and the half nut 12 is engaged with the tie bar 9. Then, high pressure hydraulic oil is supplied to the mold clamping oil chamber 10a of the mold clamping cylinder to generate a large mold clamping force (FIG. 2). At this time, a uniform surface pressure is generated on the entire mold parting surface due to the effect of the gradient processing of the fixed platen 4 and the movable platen 5 described above.

  When the mold clamping force rises to a desired value, molten aluminum or resin is injected and filled into the mold cavity from the injection device at high pressure. Since the surface pressure for aligning the parting surfaces is uniformly generated, there is no portion where the parting surface opens and burrs are generated under the pressure of the melt.

  When the cooling and solidification is completed, the pressure in the mold clamping oil chamber 10a is dropped, the hydraulic oil is supplied to the mold release oil chamber 10b, the mold is slightly opened with a large force, and the molded product is separated from the fixed mold 1. After the half nut 12 is opened and separated from the tie bar 9, the mold opening / closing servo motor 30 is driven to move the movable mold 2 and the movable platen 5 backward (open). Further, the molded product is detached from the movable mold 2 by an unillustrated extrusion device and carried out of the machine by a take-out device. Subsequently, the next molding cycle is started.

  The above-described embodiment is an example of the present invention, and the present invention is not limited by the embodiment, and is defined only by matters described in the claims, and other embodiments are also possible. It can be implemented.

  It can be used for mold clamping devices of molding machines that produce aluminum products and plastic products, and can contribute to improving the quality of molded products and reducing failures in molding machines.

1 fixed type 2 movable type 4 fixed platen 4a fixed platen plane 4b fixed platen gradient surface 5 movable platen 5a movable platen plane 5b movable platen gradient surface 7 fixed plate 8 movable plate 9 tie bar 9a engaging portion 10 piston 10a mold oil chamber 10b Release oil chamber 11 Rod 12 Half nut 13 Injection hole 15 Machine base 16 Fixed key 20 Fixed bolt 24 Movable base 25 Slide rail 26 Slide block 30 Mold opening / closing servo motor 31 Mold opening / closing ball screw shaft 32 Mold opening / closing ball screw nut 33 Nut mounting block 34 Screw shaft support base 35 Brake 37 Coupling 38 Screw shaft support base

Claims (1)

Machine base,
A fixed plate that is fixedly placed on the machine base and holds a fixed mold;
A stationary platen placed on the anti-mold side of the stationary plate;
A movable plate that is slidably mounted in the mold opening and closing direction on the machine base and holds a movable mold;
A movable platen slidably mounted in the mold opening and closing direction on the opposite mold side of the movable plate;
4 tie bars that receive clamping force,
A clamping cylinder provided in the fixed platen, wherein the tie bar and the piston are integrated to generate a clamping force;
A half nut provided in the movable platen and capable of disengaging from the tie bar;
In a mold clamping device comprising a movable plate and a mold opening and closing device capable of driving the movable platen to open and close,
The surface of the fixed platen that comes into contact with the fixed plate and the surface of the movable platen that comes into contact with the movable plate have a flat surface at the center and a conical or pyramidal inclined surface. And
When the fixed platen and the movable platen are bent and deformed by receiving the maximum clamping force, the corners of the boundary line between the plane and the sloped surface form contact portions that come into contact with the fixed plate and the movable plate. In addition, the angle on both sides of the contact portion with respect to the fixed plate and the movable plate is substantially equal to the angle θ in the diagonal direction of the tie bar,
When not receiving a mold clamping force, it said inclined surface portion, the angle between the planar portion of the fixed plate and the movable plate is formed to be 2 [Theta] ° in a diagonal direction of the tie bar,
A mold clamping device characterized by that.

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