JP2009248464A - Clamping device of injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the quality of an injection molding product by minimizing the amount of deformation of a mold attaching surface of a movable plate. <P>SOLUTION: This clamping device is provided with a connection rib 10 connecting a pair of toggle brackets 62A, 62B, and a rod-like connection member 20 extended along the advance/retreat direction of the movable plate 3, which is connected to the connection rib 10 at its rear end 20b and connected to the movable plate 3 at its front end 20a. The front end 20a of the connection member 20 connected to the movable plate 3 is positioned in the center between the pair of toggle brackets 62A, 62B in the movable plate 3. A male screw section 23 is formed in the end on the connection rib 10 side of the connection member 20, and a female screw section 14 screwed in the male screw section 23 is formed in the connection rib, thereby making an axial force acted on the axial direction of the connection member 20 adjustable. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mold clamping device of an injection molding machine including a movable plate that moves in a forward / backward direction with respect to a fixed platen.

Conventionally, the injection molding method has been used because it can efficiently produce a large number of molded products with complicated shapes. Generally, horizontal injection molding machines open and close the mold by moving the movable plate forward and backward with respect to the fixed platen by the mold clamping mechanism. And a mold clamping device configured to perform a mold clamping operation.
The mold clamping device is a fixed plate for fixing the fixed side mold, and is disposed at a position facing the fixed plate and moves in the forward and backward direction with respect to the fixed plate, and the fixed movable side mold is moved to the fixed side mold. A movable plate that is engaged with the mold and clamped, an end plate provided on the retreat side in the advancing and retreating direction of the movable plate, and one end to the fixed plate and the other end to the end plate while supporting the movable plate so as to be able to advance and retreat. The structure includes a fixed tie bar and a toggle mechanism for moving the movable plate in the forward and backward directions with respect to the fixed plate using the tie bar as a guide.

Such a horizontal injection molding machine has a structure in which toggle brackets constituting a link mechanism of a toggle link provided in a pair of upper and lower pairs with respect to the movable plate are connected by ribs, so that the mold is clamped to the movable plate. There is a structure for the purpose of preventing the pair of upper and lower toggle brackets from opening in the vertical direction when a force is generated and suppressing the deformation of the mold mounting surface of the movable platen (for example, see Patent Document 1). ).
No. 6-39959

  However, in recent years, in the mold clamping device of a horizontal injection molding machine, the accuracy required for plastic injection molded products has been increased, and the accuracy of the mold itself has been improved, which occurs during the mold clamping operation. It is desired to reduce the amount of deformation of the movable plate, and there is room for improvement in that respect.

  The present invention has been made in view of the above-described problems. The mold clamping of an injection molding machine capable of improving the quality of an injection molded product by suppressing the deformation amount of the mold mounting surface of the movable platen to be small. An object is to provide an apparatus.

  In order to achieve the above object, in a mold clamping device for an injection molding machine according to the present invention, a fixed plate, a movable plate for clamping a mold between the fixed plate, and a pair of toggle brackets fixed to the movable plate A mold clamping device of an injection molding machine having a toggle link connected to each of the two and a toggle mechanism for moving the movable plate forward and backward relative to the fixed platen, and connecting a pair of toggle brackets A connecting rib, and one end connected to the connecting rib, the other end connected to the movable platen, and a rod-like connecting member extending along the advancing and retreating direction of the movable platen. It is characterized by being located in the center between the toggle brackets.

  In the present invention, the center between the pair of toggle brackets in the movable plate is stretched from the rear end face side by the connecting member. And the clamping force which acts on a metal mold | die attachment surface acts on the connection rib which conventionally only suppressed the force which acts in the direction which toggle brackets leave | separate via a connection member. For this reason, the mold clamping force received by the mold mounting surface is borne by both the mold mounting surface and the connecting rib connected to the connecting member, and the deformation of the mold mounting surface can be reduced. In addition, the mold clamping force acting on the connecting rib acts in a direction substantially orthogonal to the axial direction of the connecting rib, and acts in a direction to suppress the force acting in the direction in which the pair of toggle brackets are separated from each other. The effect of reducing the amount of deformation of the movable plate can be obtained.

  In the mold clamping device for an injection molding machine according to the present invention, it is preferable that an axial force adjusting means for adjusting the axial force acting in the axial direction of the connecting member is provided.

  In the present invention, an axial force for preloading or pretensioning is applied to the connecting member in advance by the axial force adjusting means so that the movable plate is pressed in the mold clamping direction, or the direction opposite to the mold clamping direction (from the fixed plate side to the rear side). It is possible to pull in the direction toward the end side), and the amount of deformation of the mold mounting surface when the mold clamping force is generated can be appropriately adjusted. That is, when a preload is applied to the connecting member, the deformation of the mold mounting surface can be reduced, and conversely, when a pretension is applied, the deformation can be increased. Therefore, even when using a mold whose strength is adjusted according to the rigidity of the movable platen, it is possible to accurately mold by adjusting the amount of deformation of the mold mounting surface that matches the strength of the mold. it can.

Further, in the mold clamping device of the injection molding machine according to the present invention, the axial force adjusting means is screwed into the male screw portion formed at the end portion of the connecting member on the connecting rib side and the male screw portion formed on the connecting rib. It is preferable to consist of an internal thread part.
In the mold clamping device of the injection molding machine according to the present invention, the axial force adjusting means is screwed into a male screw portion formed at the end of the connecting member on the movable platen side and a male screw portion formed on the movable platen. It is preferable to consist of an internal thread part.

  In the present invention, the male threaded portion formed at one end of the coupling member is screwed into the female threaded portion formed on the coupling rib or the movable plate and tightened appropriately, so that a preload or pretension is preliminarily applied to the coupling member before mold clamping. This makes it possible to adjust the deformation amount of the mold mounting surface when the mold clamping force is generated.

  According to the mold clamping device of the injection molding machine according to the present invention, a part of the mold clamping force received by the mold mounting surface of the movable plate at the time of mold clamping can be borne by the coupling rib via the coupling member. The amount of deformation of the mold mounting surface of the movable plate can be kept small, and the quality of the injection molded product can be improved.

Hereinafter, a first embodiment of a mold clamping device of an injection molding machine according to the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 is a side view showing a schematic configuration of a mold clamping device of an injection molding machine according to a first embodiment of the present invention, and FIG. 2 is a partially broken side view showing a configuration of a connecting member connected to a movable platen. 3 is an AA arrow view shown in FIG. 2, FIG. 4 is an enlarged view of a joined state of the connecting rib and the connecting member shown in FIG. 2, and FIG. 5 is a diagram for explaining the operation of the connecting member.

Reference numeral 1 shown in FIG. 1 indicates a mold clamping device of a horizontal injection molding machine (injection molding machine) according to the first embodiment.
As shown in FIG. 1, the mold clamping device 1 includes a stationary platen 2 to which a stationary mold K1 is fixed, and one side surface that is disposed facing the stationary platen 2 and faces the stationary mold K1 ( The movable mold K2 is fixed to the mold mounting surface 3a) and moved in the advancing / retreating direction (the direction of arrow E shown in FIG. 1, the opening / closing direction of mold clamping) with respect to the fixed platen 2 to move the movable mold K2. A movable platen 3 that is engaged with the fixed side mold K1 to clamp the mold, an end plate 4 provided on the rear side in the advancing and retreating direction of the movable platen 3, and one end of the movable platen 3 that supports the movable platen 3 so as to advance and retreat. A plurality of (four, only two shown in FIG. 1) tie bars 5, 5,... With the other end fixed to the end plate 4, and the movable plate 3 are fixed by guiding these tie bars 5. Move in the advancing and retreating direction with respect to the board 2 to open / close and move the mold of the movable mold K2 with respect to the fixed mold K1 And a toggle mechanism 6 for performing.

The fixed platen 2 and the end plate 4 are fixed at predetermined positions on the machine base 7, and the movable platen 3 is supported by a linear guide 31 that slides along a guide rail 8 fixed on the machine base 7. It has become.
In the following description, the forward side in the advancing / retreating direction of the movable platen 3 is “front” and “front end”, and the backward side is “rear” and “rear end”.

  In the toggle mechanism 6, toggle links 61 (61A, 61B) linked to each other are arranged above and below the mold clamping device 1, and one end 61a on the front end side of each of the toggle links 61A, 61B is a rear surface 3b ( The other end 61 b on the rear end side is connected to the end plate 4, and is connected to a toggle bracket 62 (62 </ b> A, 62 </ b> B) fixed to the mold mounting surface 3 a. Then, by moving the cross head 63 between the movable platen 3 and the end plate 4 via the screw shaft 64 by a driving device such as an electric motor (not shown), the toggle links 61A and 61B supported by the cross head 63 are moved. The movable platen 3 is advanced and retracted along the tie bars 5, 5,..., And the pair of molds K1, K2 held by the fixed platen 2 and the movable platen 3 are clamped or opened.

  As shown in FIGS. 2 and 3, the mold clamping device 1 includes a connecting rib 10 that vertically connects the toggle brackets 62 </ b> A and 62 </ b> B fixed to the upper and lower ends of the rear surface 3 b of the movable platen 3. And a pair of connecting members 20 (20A, 20B) for connecting the connecting rib 10 and the movable platen 3 are provided.

  The connecting rib 10 includes a rib main body 11 having an insertion hole 12 through which the pair of connecting members 20A and 20B are inserted, and a ring-shaped nut that is fixed to the rib main body 11 coaxially with the insertion hole 12. It consists of the member 13. As shown in FIG. 4, the nut member 13 is formed with a female screw portion 14 that is screwed into a male screw portion 23 of a connecting member 20 described later on the inner surface thereof, and a plurality of bolts 15, 15,. It is fixed to the rear surface 11b, and the internal thread portion 14 of the nut member 13 and the insertion hole 12 communicate with each other.

  As shown in FIGS. 2 and 3, the connecting members 20A and 20B are rod-shaped and pass through the center of the movable plate 3 in the vertical direction (the center between the pair of toggle brackets 62A and 62B). It extends along the moving direction (the direction of arrow E shown in FIG. 1, the mold clamping direction) and is arranged at a symmetric position (left and right direction in FIG. 3) with respect to the center of the movable platen 3 at a predetermined interval. Thus, since the pair of connecting members 20A and 20B are arranged symmetrically with respect to the center of the movable platen 3, it is possible to eliminate variations in the supporting force with respect to the movable platen 3.

  Each connecting member 20 has a screw hole 21 formed at the front end 20a, and the front end 20a is inserted and engaged with the rear surface 3b of the movable platen 3, and the mold mounting surface 3a of the movable platen 3 is inserted into the screw hole 21. Screwed from the side by a bolt 22 and fixed to the movable platen 3. That is, a recess 32 is formed at the center of the rear surface 3 b of the movable plate 3, and the front end 20 a of the connecting member 20 is fitted in the recess 32. Then, in a state where the front end 20 a of the connecting member 20 is fitted in the recess 32 and the bolt 22 is screwed into the screw hole 21, the connecting member 20 is rotatable to the movable platen 3 around its central axis. It is supported. Further, the connecting member 20 has a male screw portion 23 formed on the peripheral surface of the rear end 20b, and is provided so as to be able to be screwed to the female screw portion 14 of the connecting rib 10 described above.

  And the connection member 20 becomes a structure which can adjust the axial force which acts on the axial direction (arrow E direction, the same direction as a mold clamping direction). And the connection member 20 has the mechanism (henceforth a rotation mechanism) which does not illustrate which rotates the connection member 20 centering on a center axis line in the rear end 20b. That is, by rotating each connecting member 20 in the forward and reverse directions using this rotating mechanism, the front end 20a rotates with respect to the movable platen 3 in the recess 32 together with the bolt 22, and the external thread portion 23 of the rear end 20b. Is threadably engaged with the female threaded portion 14, and is thus configured to move relative to the nut member 13 (the connecting rib 10) in the axial direction so that the axial force of the connecting member 20 can be adjusted. The male screw portion 23 of the connecting member 20 and the female screw portion 14 of the nut member 13 correspond to the axial force adjusting means of the present invention.

Next, the operation of the mold clamping apparatus 1 having the above configuration will be described with reference to FIG.
As shown in FIGS. 1 and 5, the crosshead 63 of the toggle mechanism 6 is moved to the fixed platen 2 side to move the movable platen 3 forward, and the fixed mold K1 and the movable mold K2 are clamped. The amount of deformation on the upper and lower end sides of the movable platen 3 becomes larger than the center position due to the mold clamping force, and accordingly, a force acts in a direction in which the pair of toggle brackets 62A and 62B are separated from each other (arrow F1 direction).

  On the other hand, in the mold clamping device 1 according to the present embodiment, a pair of toggle brackets 62A and 62B provided on the movable platen 3 are respectively connected by the connecting ribs 10, and the connecting rib 10 and the central portion of the movable platen 3 are connected. 3c is connected by the connecting member 20, and the center between the pair of toggle brackets 62A and 62B in the movable platen 3 is stretched by the connecting member 20 from the rear surface 3b side.

  Then, as shown in FIG. 5, in the conventional art, the connecting rib 10 that merely suppresses the force acting in the direction in which the toggle brackets are separated from each other (the direction of the arrow F1) acts on the mold mounting surface 3a of the movable platen 3. The clamping force to be applied acts via the connecting member 20. Therefore, the mold clamping force received by the mold mounting surface 3a is borne by both the mold mounting surface 3a and the connecting rib 10 connected to the connecting member 20, and the deformation of the mold mounting surface 3a can be reduced. it can. Further, the mold clamping force acting on the connecting rib 10 acts in a direction substantially orthogonal to the axial direction of the connecting rib 10, and a force acting in a direction (arrow F1 direction) in which the pair of toggle brackets 62A and 62B are separated from each other. Since it works in the direction of restraining (arrow F2 direction), the effect of reducing the deformation amount of the movable platen 3 is obtained.

  Further, in the mold clamping apparatus 1, an axial force for preloading or pretensioning is applied to the connecting member 20 in advance to press the movable plate 3 in the mold clamping direction (arrow E1 direction), or opposite to the mold clamping direction. It is possible to pull in the direction (direction from the fixed platen 2 side toward the rear side, arrow E2 direction), and the amount of deformation of the mold mounting surface 3a when the mold clamping force is generated can be adjusted as appropriate. That is, the deformation of the mold mounting surface 3a can be reduced when a preload is applied to the connecting member 20, and the deformation can be increased when a pretension is applied. Therefore, even when a mold whose strength is adjusted according to the rigidity of the movable platen 3 is used, the amount of deformation of the mold mounting surface 3a that matches the strength of the mold is adjusted and molded accurately. be able to.

  As described above, in the mold clamping device of the injection molding machine according to the first embodiment, a part of the mold clamping force received by the mold mounting surface 3a of the movable platen 3 is clamped via the connecting member 20 during mold clamping. Since the connecting rib 10 can be burdened, the amount of deformation of the mold mounting surface 3a of the movable platen 3 can be kept small, and the quality of the injection molded product can be improved.

Next, other embodiments will be described with reference to the accompanying drawings. However, the same or similar members and parts as those of the above-described first embodiment are denoted by the same reference numerals, and description thereof is omitted. A configuration different from the embodiment will be described.
FIG. 6 is a partially cutaway side view showing the mold clamping device according to the second embodiment and corresponds to FIG.
As shown in FIG. 6, the second embodiment has a configuration in which the male screw portion 23 of the connecting member 20 is formed at the front end 20 a. Here, since the connection structure of the toggle bracket 62 (62A, 62B) and the connection rib 10 is the same as that of the first embodiment, detailed description thereof is omitted. That is, the connecting member 20 has a male screw portion 23 formed at the front end 20a (end on the movable platen 3 side) and a screw hole 21 formed at the rear end 20b. The movable plate 3 is formed with a female screw portion 33 for screwing the male screw portion 23 of the connecting member 20. In the connecting rib 10, the nut member 13 (see FIG. 2) of the first embodiment described above is omitted, and a recess 16 is formed in the front surface 11 a of the rib body 11 to fit the rear end 20 b of the connecting member 20. ing. The connecting member 20 is screwed into the screw hole 21 with the bolt 22 from the rear surface 11b side of the rib main body 11 and fixed to the connecting rib 10 with the rear end 20b of the connecting member 20 fitted in the recess 16. Yes.

  In the second embodiment, a screw structure including a male screw portion 23 and a female screw portion 33 is provided on the movable platen 3. However, the mold mounting surface 3 a of the movable platen 3 is provided during mold clamping. Since a part of the clamping force to be received can be applied to the connecting rib 10 via the connecting member 20, the mold mounting surface of the movable platen 3 is the same as in the first embodiment described above. The amount of deformation of 3a can be kept small, and the quality of the injection molded product can be improved.

As mentioned above, although embodiment by the mold clamping apparatus of the injection molding machine by this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably. .
For example, in the present embodiment, the pair of connecting members 20A and 20B are arranged at symmetrical positions with respect to the center of the movable platen 3, but the number is not limited to this. In short, it is only necessary that the support force is arranged in a symmetrical position from the center of the movable platen 3 so that the support force does not vary. For example, four connecting members may be arranged.
In the first embodiment, the nut member 13 of the connecting rib 10 that is screwed into the male screw portion 23 of the connecting member 20 is fixed to the rib body 11 with the bolts 15. However, the present invention is not limited to this. A structure in which the member 13 is integrally formed with the rib main body 11 may be used.

Further, the shape, size, length, thickness, etc. of the connecting rib 10 and the connecting member 20 are not particularly limited, and conditions such as the size of the movable platen 3, the weight of the mold, the clamping force, etc. It can be arbitrarily set according to.
Further, the connecting member 20 may have a structure that also serves as a guide bar for an ejector device used in an injection molding machine. As a result, it is possible to greatly change the structure of the injection molding machine or suppress the increase in size of the injection molding machine by adding a new part to the conventional part.

It is a side view which shows schematic structure of the mold clamping apparatus of the injection molding machine by the 1st Embodiment of this invention. It is a partially broken side view which shows the structure of the connection member connected with a movable board. It is an AA arrow directional view shown in FIG. It is an enlarged view of the joining state of the connecting rib and connecting member shown in FIG. It is a figure explaining the effect | action of a connection member. It is a partially broken side view which shows the mold clamping apparatus by 2nd Embodiment, Comprising: It is a figure corresponding to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Clamping device 2 Fixed board 3 Movable board 3a Mold mounting surface 3b Rear surface 3c Center part 6 Toggle mechanism 10 Connecting rib 13 Nut member 14, 33 Female thread part 15 Bolt 20 Connecting member 21 Screw hole 22 Bolt 23 Male thread part 62, 62A 62B Toggle bracket

Claims (4)

A fixed plate, a movable plate for clamping the mold between the fixed plate and a toggle link connected to each of a pair of toggle brackets fixed to the movable plate, and the movable plate is fixed A mold clamping device of an injection molding machine provided with a toggle mechanism for moving forward and backward with respect to the board,
A connecting rib for connecting the pair of toggle brackets;
A rod-shaped connecting member that connects one end to the connecting rib and the other end to the movable plate, and extends along the advancing and retreating direction of the movable plate;
With
The mold clamping device of an injection molding machine, wherein the other end of the connecting member connected to the movable platen is located at the center between the pair of toggle brackets on the movable platen.   2. The mold clamping apparatus for an injection molding machine according to claim 1, further comprising an axial force adjusting means for adjusting an axial force acting in an axial direction of the connecting member.   The axial force adjusting means includes a male screw portion formed at an end portion of the connecting member on the connecting rib side, and a female screw portion screwed into the male screw portion formed in the connecting rib. A mold clamping device for an injection molding machine according to claim 2.   The axial force adjusting means includes a male screw portion formed at an end portion of the connecting member on the movable platen side, and a female screw portion screwed into the male screw portion formed on the movable platen. A mold clamping device for an injection molding machine according to claim 2.

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