JP5276953B2 - Clamping device and injection molding machine - Google Patents

Abstract

A fixed template (22) and a rear plate (44) are connected together with four tie bars (60). A movable template (26) is movably arranged between the fixed template (22) and the rear plate (44). An elbow-bar mechanism (46) is connected with the movable template (26). A fixed metal mould (32) and a movable metal mould (34) are fastened together between the fixed template (22) and the movable template (26) so as to form a metal mould. Then, a planar pressure adjusting part (74) is arranged and can reduce the pressure difference of the interfaces between the fixed metal mould (32) and the movable metal mould (34). Therefore, a mould fastener for fastening the metal mould (32) and the movable metal mould (34) by the homogeneous planar pressure is provided.

Description

  The present invention relates to a mold clamping device that reduces a pressure difference generated along a joint surface between a fixed mold and a movable mold when mold clamping is performed.

  The mold clamping device needs to securely clamp the fixed mold and the movable mold against the pressure of the resin injected into the mold cavity. If the pressure of the resin cannot be countered and a gap is formed on the joint surface between the fixed mold and the movable mold, burrs are generated in the product. On the other hand, when excessively high pressure acts on the mold, the mold may be deformed or the mold itself may be damaged.

Therefore, for example, an invention is known in which a distortion generation preventing portion is provided between a fulcrum of a toggle arm of a movable platen and a mold mounting surface to prevent distortion from occurring on the mold mounting surface.
JP-A-11-170322

  However, in a mold clamping device that clamps a mold by connecting a rear plate and a fixed platen with a tie bar and pressing the movable platen against the fixed platen side with a toggle mechanism, the pressing force in the vicinity of the fixed platen's tie bar is usually applied. It becomes higher than the pressing force of other parts.

  Accordingly, even if a distortion preventing portion is provided on the mold mounting surface of the movable platen as in the above-described conventional example to prevent the distortion of the mold mounting surface of the movable platen, the difference in pressing force between the fixed platen and the stationary platen is prevented. Therefore, when the mold is clamped, the fixed mold and the movable mold may not be joined with a uniform surface pressure.

  The present invention solves the above-mentioned problems, and when the mold is clamped, the pressure difference along the joint surface between the fixed mold and the movable mold is reduced, and the fixed mold and the movable mold are joined at a uniform surface pressure. It is an object of the present invention to provide a mold clamping device that can be made to operate.

  In the present invention, in order to solve the above problem, the mold clamping device is configured as follows.

A fixed die plate, a fixed die mounting board that is assembled to the fixed die plate and to which a fixed die is attached, four tie bars having one end connected to the four corners of the fixed die plate, and four tie bars at the four corners. A rear plate having the other end connected thereto, a movable die plate movably provided between the fixed die plate and the rear plate, a movable die mounting plate attached to the movable die plate, to which a movable die is attached, Two sets of toggle mechanisms provided between the rear plate and the movable die plate and moving the movable die plate forward and backward , a pair of toggle arms attached to the rear plate side of the movable die plate, and a movable die A mounting surface provided on the plate and in contact with the movable mold mounting plate; and provided continuously from the mounting surface toward the outside of the mounting surface. The pair of toggle arms that reduce a pressure difference caused by clamping along the joint surface between the stationary mold and the movable mold, which occurs when the stationary mold and the movable mold are clamped by a mechanism. And an extending portion extending between the two and the mold clamping device is configured.

  Further, an injection molding machine was configured with the mold clamping device described above.

According to the mold clamping device of the present invention, by providing the extending portion on the movable die plate, the pressure difference generated along the joint surface between the fixed mold and the movable mold is reduced, and the fixed mold and the movable mold are reduced. Can be joined at a uniform surface pressure.

  By configuring an injection molding machine using such a mold clamping device, the fixed mold and the movable mold can be joined with a substantially uniform surface pressure, so that there is little occurrence of defective products due to burrs and due to excessive pressure. It is possible to provide an injection molding machine that prevents deformation and damage of the mold.

  An embodiment of a mold clamping device according to the present invention will be described with reference to the drawings. FIG. 7 shows an injection molding machine 10 provided with a mold clamping device 14.

  The injection molding machine 10 includes a base 50, an injection device 12 and a mold clamping device 14 provided on the base 50, and the like. Further, the display means 16 and the input means 18 of the injection molding machine 10 are provided in the substantially central portion of the injection molding machine 10.

  The base 50 is a substantially rectangular parallelepiped, and a rail 52 is provided on the upper surface of the base 50. The rail 52 is provided along the longitudinal direction of the base 50, and the injection device 12 is movably mounted on the rail 52.

  The injection device 12 includes a cylinder 20 having a screw therein, a drive mechanism (both not shown) that rotates the screw around an axis and moves back and forth in the axial direction, a hopper 56, and the like. ing. The injection device 12 injects molten resin from a cylinder 20 into a cavity of a mold 36 to be described later by advancing a screw by a drive mechanism. On the left side portion of the base 50, a mold clamping device 14 having a mold 36 is provided so as to face the injection device 12. The injection device 12 and the mold clamping device 14 each have a cover on the outside, and FIG. 7 shows a state covered with the cover.

  The mold clamping device 14 is shown in FIG. Hereinafter, the mold clamping device 14 will be described assuming that the injection device 12 side of the mold clamping device 14 is the front, the front, rear, right and left are defined as a reference, the direction of gravity is downward, and vice versa.

  The mold clamping device 14 includes a fixed die plate 22, a fixed mold attachment board 24 attached to the fixed die plate 22, a movable die plate 26, and a movable mold attachment board 28 attached to the movable die plate 26. And a drive mechanism 30 and the like. A mold 36 composed of a fixed mold 32 and a movable mold 34 is assembled between the fixed mold mounting board 24 and the movable mold mounting board 28.

  The drive mechanism 30 includes a drive motor 42, a rear plate 44, a toggle mechanism 46, a tie bar 60, and the like. The drive motor 42 is attached above the rear plate 44, and the drive shaft of the drive motor 42 is coupled to the screw shaft 45 of the ball screw mechanism via the transmission belt 43. The rear plate 44 is movably provided on the base 50 and is disposed at a predetermined position on the base 50 determined by the thickness of the mold 36.

  Ends on the rear side of the tie bar 60 are attached to the four corners of the rear plate 44. A total of four tie bars 60 are provided, and the front ends of the tie bars 60 are attached to the four corners of the fixed die plate 22.

  The toggle mechanism 46 includes a toggle lever 48, a cross head 62, a toggle arm 64, and the like. A pair of toggle levers 48 are provided on the top and bottom, and a pair of toggle levers 48 are also provided side by side. One end of the toggle lever 48 is rotatably attached to the support portion 47 of the rear plate 44. The left and right toggle levers 48 are connected to each other by a connecting shaft 66 on the upper and lower sides.

  The cross head 62 has a threaded portion (not shown) of a ball screw mechanism at the center. The screw portion is screwed onto the screw shaft 45 and is screwed back and forth by the rotation of the screw shaft 45 to move the cross head 62 forward and backward. One end of a connecting piece 68 is attached to the upper and lower ends of the cross head 62. The other end of the connecting piece 68 is connected to the connecting shaft 66, and the upper and lower ends of the cross head 62 are connected to the toggle lever 48 via the connecting piece 68.

  One end of the toggle arm 64 is rotatably connected to the toggle lever 48, and the other end is rotatably attached to the support portion 27 of the movable die plate 26. As shown in FIG. 4, the toggle arm 64 is provided with a pair of upper and lower toggle arms 64 arranged side by side in the same manner as the toggle lever 48. The support portions 27 are provided at the four corners of the movable die plate 26 and at the centers of the upper edge portion and the lower edge portion, respectively.

  Here, the pair of toggle means is a so-called double toggle means, and is configured by combining a mechanism having a toggle action including a toggle lever 48, a toggle arm 64, a cross head 62, and the like in a pair of upper and lower sides. The two sets of toggle means means that two identical one set of toggle means are arranged side by side. It should be noted that the combination of the pair of toggle means may be reversed upside down, left and right with respect to the above example.

  The fixed die plate 22 is fixed on the base 50. The fixed die plate 22 has the same structure as that of the prior art, and a fixed mold mounting board 24 is attached to the surface (on the rear side) of the fixed die plate 22. A mold 32 is attached.

  The movable die plate 26 is disposed between the fixed die plate 22 and the rear plate 44 so as to be movable back and forth. The movable die plate 26 is shown in FIGS. The movable die plate 26 has tie bar insertion holes 70 at four corners thereof, and the tie bar 60 is slidably inserted into the tie bar insertion holes 70. The support portion 27 described above is provided on the rear side of the movable die plate 26, and a toggle arm 64 is rotatably connected as shown in FIGS.

  The movable die plate 26 has a mounting surface 72 on the front side. The front surface side of the movable die plate 26 is a surface to which the movable mold mounting plate 28 is attached. When the movable die mounting plate 28 is attached to the movable die plate 26, the mounting surface 72 is provided on the back side of the movable die mounting plate 28. Direct contact.

  The mounting surface 72 is formed narrower than the back surface of the movable mold mounting plate 28 so as to be positioned inside the back surface of the movable mold mounting plate 28 when the movable mold mounting plate 28 is mounted on the movable die plate 26. (In FIG. 1, the outer shape of the movable mold mounting plate 28 is shown by a two-dot chain line.) And, an extending portion 74 as a surface pressure adjusting portion is provided at the center of the upper edge and the lower edge of the mounting surface 72, respectively. ing. Note that the shape of the mounting surface 72 may be rectangular or square, and may be appropriately changed according to the size and shape of the mold 36, the shape of the product to be molded, and the like. It may be square.

  Next, the extension part 74 will be described. The extending portion 74 provided on the upper edge of the mounting surface 72 extends upward so as to pass between the left and right tie bar insertion holes 70 provided on the upper portion of the movable die plate 26 and the tie bar insertion holes 70. The extending portion 74 provided at the lower edge of the mounting surface 72 extends downward so as to pass between the tie bar insertion holes 70 adjacent to the left and right provided at the lower portion of the movable die plate 26. . Each of the upper and lower extending portions 74 has the same height as the mounting surface 72, and the length of each of the extended portions 74 is changed from the movable mold 34 to the movable die plate 26 via the movable mold mounting plate 28. When attached, the upper edge and the lower edge of the extending portion 74 are formed so as to reach the vicinity of the upper edge and the lower edge of the movable mold 34.

  The movable mold mounting plate 28 is a flat plate member as shown in FIGS. 3 and 4 and has a hole through which an extrusion pin (not shown) is passed, a mounting hole for mounting the movable mold 34, and the like appropriately formed. ing. The surface A of the movable mold mounting board 28 is a surface to which the movable mold 34 is attached and is formed flat.

  The back surface B of the movable mold mounting board 28 is a surface to be attached to the movable die plate 26, and a stepped portion 29 is formed on the back surface B as shown in FIG. The high portion of the stepped portion 29, that is, the portion protruding to the rear side of the movable mold mounting plate 28 is formed substantially equal to the shape of the mounting surface 72 including the extending portion 74, and the movable mold mounting plate 28 is movable. When attached to the die plate 26, the attachment surface 72 is formed so as to be in contact with it. In addition, the back surface B of the movable mold mounting board 28 does not have the stepped portion 29, and the entire surface may be formed flat like the surface A.

  Next, the operation and effect of the mold clamping device 14 will be described. First, a fixed mold mounting board 24 is attached to the back side of the fixed die plate 22, and a movable mold mounting board 28 is attached to the front side of the movable die plate 26. Further, the fixed mold 32 is mounted on the fixed mold mounting board 24, and the movable mold 34 is mounted on the movable mold mounting board 28. Moreover, the attachment position of the tie bar 60 and the rear plate 44, the operation range of the toggle mechanism 46, etc. are adjusted as needed.

  When the drive motor 42 is operated and the toggle mechanism 46 advances the movable die plate 26, the movable die 34 is advanced via the movable die mounting plate 28 and the die 36 is closed. When the mold 36 is clamped with a predetermined pressure by the toggle mechanism 46, the injection device 12 injects resin into the cavity of the mold 36, and a product is molded.

  In a state where the mold 36 is clamped, the movable die plate 26 comes into contact with the movable mold mounting plate 28 at the mounting surface 72 having the extending portion 74 as a pressure adjusting portion, and the movable die plate 26 passes through the mounting surface 72. The back surface B of the mold mounting board 28 is pressed. Then, a portion with a high pressure corresponding to the extending portion 74 provided on the movable die plate 26 is generated at substantially the central portion of the upper and lower portions of the movable mold mounting plate 28.

  When the mold 36 is clamped by the toggle mechanism 46, the fixed die plate 22 is pulled to the left (rear side) in FIG. Then, a high pressure is generated in the vicinity of the four corners of the fixed die plate 22 to which the four tie bars 60 are fixed, and the high pressure is transmitted to the fixed mold mounting plate 24, and a high pressure is applied to the four corners of the fixed mold mounting plate 24. Part occurs.

  As described above, in the mold clamping device 14, when the mold 36 is clamped by the toggle mechanism 46, high pressure portions are generated at the four corners of the fixed mold mounting plate 24, and the upper and lower centers of the movable mold mounting plate 28 are formed. A portion having a high pressure is generated by the extended portion 74. Therefore, a pressure distribution is generated on the fixed mold mounting plate 24 and the movable mold mounting plate 28 so as to complement the strength of the pressure. That is, as shown in FIG. 4, the movable mold mounting plate 28 is urged in a direction in which it is deformed forward as indicated by a two-dot chain line X, and the fixed mold mounting plate 24 is moved by a two-dot chain line Y. As shown, it is biased in the direction of deforming backwards into a concave shape. That is, the portion that generates high pressure on one side becomes a low pressure portion on the opposite side, and the low pressure portion on one side becomes a high pressure portion on the opposite side. As a result, the movable mold 34 and the fixed mold 32 attached between the movable mold mounting board 28 and the fixed mold mounting board 24 have a pressure difference along the joint surface between the movable mold 34 and the fixed mold 32. Can be relaxed and the pressure difference is small, that is, bonding can be performed with uniform pressure along the bonding surface.

  Therefore, the mold clamping device 14 can clamp the mold 36 with an appropriate pressure with little variation along the joint surface, and in injection molding, the product is less likely to generate burrs and the mold Generation of deformation or damage can be prevented.

  In the above example, the extending portion 74 as the pressure adjusting portion is provided on the mounting surface 72 of the movable die plate 26. However, the mounting surface 72 of the movable die plate 26 is formed flat, and the movable die mounting plate 28 You may provide the level | step-difference part 29 etc. which function as a pressure adjustment part in the back surface B. FIG. In the above example, the extended portion 74 is formed only in the vertical direction of the mounting surface 72. However, the extended portion may be provided in the horizontal direction of the mounting surface 72 or in the cross shape of the vertical and horizontal directions. Furthermore, the extended portion only needs to correspond to a portion of high pressure generated in the fixed mold mounting plate 24, and may be provided not only at the center of the mounting surface 72 but also at other positions.

  Further, the pressure adjusting portion does not need to be continuous with the mounting surface 72, and may be formed by providing one or a plurality of protruding portions 75 at positions apart from the mounting surface 72 as shown in FIG.

  In the above example, the toggle mechanism 46 is a type in which the four arms are paired up and down, and these are arranged on the left and right. However, the present invention does not limit the toggle mechanism to such a type. However, as shown in the above example, when the toggle mechanism 46 of the type in which the two upper and lower toggle arms 64 are paired and arranged on the left and right sides is used, the movable die plate 26 is also connected from the toggle mechanism 46. Pressure may be applied to the four corners via the toggle arm 64. If the surface pressure adjusting part such as the extending part 74 according to the above embodiment is not provided, if the toggle mechanism 46 is configured as described above, the movable mold mounting plate 28 also has high pressure portions at the four corners. May occur. Therefore, in the mold clamping apparatus in which the pressure distribution as described above is generated on the movable mold mounting plate via the toggle arm, the mold clamping apparatus 14 of the present invention including the above-described surface pressure adjusting unit has a greater effect. It can be said that.

It is a front view which shows one Embodiment of the movable die plate concerning this invention. It is a perspective view which shows the movable die plate shown in FIG. It is a side view which shows a movable die plate and a movable mold mounting board. It is a perspective view which shows a movable die plate and a movable mold attachment board. It is a perspective view which shows a movable mold mounting board. It is a front view which shows a mold clamping apparatus. It is a perspective view which shows an injection molding machine. It is a front view which shows the state of other embodiment of a movable die plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Injection molding machine 14 ... Clamping device 22 ... Fixed die plate 24 ... Fixed mold mounting board 26 ... Movable die plate 28 ... Movable mold mounting board 30 ... Drive mechanism 36 ... Mold 46 ... Toggle mechanism 48 ... Toggle lever 60 ... Tie bar 62 ... Cross head 64 ... Toggle arm 66 ... Connection shaft 68 ... Connection piece 72 ... Mounting surface 74 ... Extension part 75 ... Projection

Claims (3)

A fixed die plate;
A fixed mold mounting board that is assembled to the fixed die plate and to which a fixed mold is attached;
Four tie bars having one end connected to the four corners of the fixed die plate;
A rear plate in which the other ends of the four tie bars are connected to four corners;
A movable die plate movably provided between the fixed die plate and the rear plate;
A movable mold mounting board assembled to the movable die plate and to which a movable mold is attached;
A toggle mechanism provided between the rear plate and the movable die plate and having two sets of toggle means for moving the movable die plate forward and backward;
A pair of toggle arms of the toggle mechanism attached to the rear plate side of the movable die plate;
A mounting surface provided on the movable die plate and in contact with the movable mold mounting plate;
The fixed mold and the movable mold, which are provided continuously from the mounting surface toward the outside of the mounting surface, and are generated when the fixed mold and the movable mold are clamped by the toggle mechanism. Extending between the pair of toggle arms to reduce the pressure difference due to the clamping along the joint surface of
A mold clamping apparatus characterized by comprising a. The mold clamping device according to claim 1, wherein the extending portion extends between the pair of toggle arms and between the adjacent tie bars . An injection molding machine comprising the mold clamping device according to claim 1.

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