JP2014128896A - Tie bar fixing structure in mold clamping device of injection machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure allowing the whole device to be simplified and small-sized, with a half nut having a shorter traveling stroke compared with a conventional one.SOLUTION: A tie bar fixing structure in the mold clamping device of an injection machine has a tie bar fixing body (50) attached to a movable platen (5), including a holding plate (30) attached to the movable platen (5), a ring-shaped supporter (33) rotatably attached to the holding plate (30), a ring-shaped sprocket (20) fixed to the ring-shaped supporter (33), a link (21) disposed between the ring-shaped supporter (33) and a half nut (6), and only one driving force (24) for rotating each of the ring-shaped sprockets (20) through an endless chain (22).

Description

  The present invention relates to a tie bar fixing structure in an injection molding machine mold clamping device, and more particularly, a novel tie bar fixing mechanism using four split nuts and moving four split nuts by a sprocket, a chain and a drive source. Regarding improvement.

First, the general configuration of the injection molding machine mold clamping device will be described.
FIG. 7 shows the mold open state. On the base 1, a fixed plate 4 having a mold clamping cylinder 2A, a mold opening / closing cylinder 3 and a fixed mold 4A of the tie bar 2 is fixedly provided. A movable mold 5 having a movable mold 5 </ b> A is movably provided at a position on the rail 1 </ b> A that is spaced apart from the fixed platen 4.

  A half nut 6 and a piston 7 are provided on the outer surface 5 a of the movable platen 5, and the tie bar 2 penetrates the insertion hole 5 a of the movable platen 5 and is a tie bar insertion hole 8 formed by a gap between the half nuts 6. It is configured so that it can be inserted into.

  As described above, in the two-platen mold in which the mold clamping device of the injection molding machine is composed of the movable platen 5 and the fixed platen 4, as shown in FIG. The movable platen 5 is brought close to the fixed platen 4 by the mold opening / closing cylinder 3 having a large stroke, and the molds 4A and 5A attached to both the movable platen 5 and the fixed platen 4 are closed. At this time, the threaded portion 2a at the tip of the four tie bars 2 protruding from the fixed platen 4 is engaged with a half nut that is divided into two parts fixed to the movable platen 5, and the movable platen 5 is restrained. A mold clamping cylinder 2A having a large diameter and a small stroke applies tension to the tie bar 2 to generate a mold clamping force, and the resin is injected from the nozzle 10a of the injection apparatus 10 into the cavity 11 between the molds 4A and 5A. In this series of operations, the present invention relates to a tie bar fixing structure that joins a tie bar 2 and a nut for restraining the movable platen 5 when the mold is closed. Has been.

The configuration of the mold clamping device of the injection molding machine of Patent Document 1 shown in FIGS. 9 to 11 will be described.
In addition, the same code | symbol is attached | subjected to the same or equivalent part as the mold clamping apparatus demonstrated in above-mentioned FIG.7 and FIG.8, the description is abbreviate | omitted and only a different part is demonstrated.
That is, the half nut 6 in FIGS. 9 and 10 is configured such that the half nut 6 in FIGS. 7 and 8 operates in the vertical direction on the base 1 to open and close, whereas the half nut 6 in the horizontal direction. 6 is opened and closed by operating.

  Further, the configuration shown in FIG. 11 is a configuration disclosed in Patent Document 1 as another form, and the half nut 6 is moved in the vertical direction, that is, in the vertical direction as in the conventional configuration shown in FIGS. 7 and 8 described above. The screw part 2a is configured to mesh or disengage.

12 and 13 show the configuration of the electric split nut opening / closing device in the mold clamping device disclosed in Patent Document 2. FIG.
In the following description, the same or equivalent parts as those in FIGS.
That is, the configuration of FIGS. 12 and 13 is a mold clamping device that is driven by an electric motor, unambiguously restrains the operation, linearly moves the half nut, and simultaneously opens and closes the two left and right tie bars with one device. This is an electric split nut opening and closing device in FIG.
In FIGS. 13 and 14, reference numeral 1 denotes a base of a mold clamping device, and a fixed platen 4 is fixed to one end of the base 1. A movable platen 5 faces the fixed platen 4 and is slidably disposed on the base 1. A fixed mold 4A is attached to the fixed platen 4, and a movable mold 5A is attached to the movable platen 5 so as to face the fixed mold 4A. Four tie bars 2 are provided between the fixed platen 4 and the movable platen 5 so as to be connected to and separated from each other. At the tips of these tie bars 2, there are provided screw portions or groove portions (hereinafter referred to as screw portions) 2a. A mold clamping cylinder 2A having a piston for generating a mold clamping force is provided at one end of the tie bar 2 on the side opposite to the screw portion 2a. The base 1 is provided with electric movable platen moving means 3. FIG. 13 shows a state in which the movable platen 5 is moved in the direction of the fixed platen 4 by the movable platen moving means 3 and the movable die 5A is brought into contact with the fixed die 4A, so-called mold closing is completed.
The movable platen moving means 3 is composed of a pair as shown in FIG.

Japanese Patent No. 3524621 Japanese Patent No. 3881850

Since the tie bar fixing structure in the conventional injection molding machine mold clamping apparatus is configured as described above, the following problems exist.
That is, as the driving means for the movable plate in the mold clamping device described above, the tie bar and the movable plate are restrained by a half nut installed on the movable plate regardless of the hydraulic drive method or the electric drive method. A method of engaging and joining the grooves is used. When the movable plate is opened and closed, the half nut has a long moving distance to escape (15 mm is required as shown in FIG. 14) in order to avoid interference with the tie bar, and requires a lot of operation time. The hydraulic drive system requires four hydraulic cylinders to drive the half nuts installed on each tie bar, and the electric drive system shown in FIG. 14 also requires two motors. It was complicated.

  The present invention has been made to solve the above-described problems, and in particular, by moving four split nuts (quarter nuts) by a sprocket and a link, the moving distance and time of the split nut are shortened. The overall configuration can be simplified and downsized.

  A tie bar fixing structure in a mold clamping device according to the present invention includes a fixed plate provided on a base and having a fixed mold and a plurality of tie bars, and a movable plate movable on the base with respect to the fixed plate. A tie bar fixing body provided on the movable plate and into which a screw portion at the tip of each tie bar is inserted, and a split nut provided on each tie bar fixing body, the bit nut being engaged with the screw portion. In the tie bar fixing structure in an injection molding machine mold clamping device in which the screw portion is fixed to the movable plate by matching, the split nut includes four pieces and is provided rotatably with respect to the movable plate side. The split nut is suspended with respect to the tie bar shaft center of the tie bar via the link by rotation of the ring sprocket. Each of the split nuts is engaged or disengaged with the threaded portion, and the annular sprockets are connected by an endless chain, and the endless chain is The tie bar fixing body is configured to be driven by only one driving source, and the tie bar fixing body is rotatably attached to the holding plate, and the annular sprocket is fixed to the holding plate. A ring-shaped holding body, a first link pin for rotatably connecting the outer end of the link to the ring-shaped sprocket, and a second link for rotatably connecting the inner end of the link to the split nut A pin and a key groove provided on the split nut for guiding the straight movement of the split nut, and provided on the holding plate and projecting toward the split nut. And a ring-shaped recess formed on an outer peripheral surface of the ring-shaped holding body, the protrusion engages with the ring-shaped recess, and the ring-shaped holding body and the ring-shaped sprocket are rotatable with respect to the holding plate. Further, the movable platen is provided with the four holding plates and the annular sprocket.

Since the tie bar fixing structure of the injection molding machine mold clamping apparatus according to the present invention is configured as described above, the following effects can be obtained.
That is, a fixed platen provided on a base and having a fixed mold and a plurality of tie bars, a movable plate movable on the base with respect to the fixed plate, and a tip of each tie bar provided on the movable platen A tie bar fixing body into which the screw portion is inserted, and a split nut provided on each tie bar fixing body, and the screw portion is fixed to the movable platen by meshing the split nut with the screw portion. In the tie bar fixing structure in the injection molding machine mold clamping apparatus, the split nut is composed of four pieces and is connected to a ring-shaped sprocket provided rotatably with respect to the movable platen side through a link, The split nuts move linearly with respect to the tie bar axis of the tie bar through the link by the rotation of the ring-shaped sprocket, and the split nuts move with respect to the threaded portion. By constituting the that was made to fit or non-meshing state, it is restrained in all the tie bars through the endless chain and links. Moreover, the movement distance accompanying opening and closing of the split nut can be shortened, and the movement time can be shortened.
In addition, since each of the ring-shaped sprockets is connected by an endless chain, and the endless chain is driven by only one driving source, all the tie bars can be fixed by one driving source.
The tie bar fixing body includes a holding plate attached to the movable platen, a ring-like holding body rotatably attached to the holding plate to which the ring-shaped sprocket is fixed, and an outer end of the link to the ring-shaped sprocket. A first link pin for pivotally connecting, a second link pin for rotatably connecting the inner end of the link to the split nut, and a linear link of the split nut provided on the split nut Therefore, the split nut moved by the link can be smoothly moved in the radial direction of the tie bar.
A protrusion provided on the holding plate that protrudes toward the split nut; and a ring-shaped recess formed on an outer peripheral surface of the ring-shaped holding body; the protrusion engages with the ring-shaped recess; Since the body and the ring-shaped sprocket are configured to be rotatable with respect to the holding plate, the sprocket can be smoothly rotated.
Further, since the movable platen is provided with the four holding plates and the annular sprocket, the four sprockets can be driven simultaneously.

It is a side view which shows the whole structure (unlocked state) of the tie bar fixing structure in the injection molding machine mold clamping apparatus by this invention. It is an enlarged view which shows the unlocking state of the principal part of FIG. It is an enlarged view which shows the locked state of the principal part of FIG. It is an enlarged view which shows the unlocking and locked state of the principal part of FIG. FIG. 5 is a cross-sectional view taken along the line AA of FIG. 4 for illustrating the relationship between the sprocket of FIG. 4 and the movable platen. It is explanatory drawing which shows the distance moved perpendicular | vertical with respect to the axial center of the tie bar of the split nut (quarter nut) of FIG. It is front sectional drawing which shows the mold open state of the conventional mold clamping apparatus. It is front sectional drawing which shows the mold closing state of FIG. It is front sectional drawing of another conventional structure. FIG. 10 is a left side view of FIG. 9. It is a front cross-sectional enlarged view which shows the other conventional example of the principal part of FIG. It is front sectional drawing which shows another conventional structure. FIG. 13 is a left side view of FIG. 12. It is explanatory drawing which shows the unlocked and locked state of the conventional tie bar.

  In the present invention, four split nuts are used, and the four split nuts are moved by a sprocket, a chain, and a drive source, and the tie bar is fixed by meshing (locking) and non-meshing (unlocking) of the tie bar. It is an object of the present invention to provide a tie bar fixing structure in an injection molding machine mold clamping device.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a tie bar fixing structure in an injection molding machine mold clamping apparatus according to the present invention will be described with reference to the drawings.
The same reference numerals are used for the same or equivalent parts as in the conventional example, and the configuration of the mold clamping device shown in FIGS. 7 and 8 is basically the same except for the configuration of tie bar fixing. The description and illustration in the present invention will be omitted by using the mold clamping device of the injection molding machine.

1 is a movable platen, and four ring-shaped sprockets 20 are rotatably provided at the four corners 5a of the movable platen 5. Are provided with four split nuts (quarter nuts) 6 obtained by dividing a ring-shaped nut into four parts every 90 degrees.
The split nuts 6 and the sprocket 20 are connected to each other by links 21 so as to be operable.

Each of the annular sprockets 20 is connected by a single endless chain 22, and this endless chain 22 is connected to a rotating shaft 25 of one motor (drive source) 24 through a pair of guide rollers 23. The sprockets 20 can be rotated simultaneously through the endless chain 22 by driving the motor 24.
The motor 24 is constituted by a known servo motor having a rotation detector such as an encoder or a resolver, and the rotation of the motor 24 allows the annular sprocket 20 to rotate slightly forward and backward through the endless chain 22. It is configured. Further, the thread portion 2 a of the tie bar 2 is inserted and positioned in the tie bar insertion hole 8 inside each split nut 6.

  FIG. 2 shows the unlocking relationship between the ring-shaped sprocket 20 of FIG. 1 and each split nut 6 and link 21. Each link 21 provided between each split nut 6 and sprocket 20 is connected to the tie bar 2. Are not aligned in the same direction as the radial direction R from the tie bar shaft center P, so that the split nuts 6 are pulled up to the sprocket 20 side. As a result, the tie bar insertion holes 8 on the inner side of the split nuts 6 Is an unlocked state in which the threaded portion 2a of the tie bar 2 is inserted and can freely enter and exit.

  Further, in the state of FIG. 3, when the endless chain 22 is slightly rotated in the CCW direction via the motor 24 in the state of FIG. 2, the sprocket 20 is also rotated by the same angle, and the link 21 is moved from the inclined state of FIG. 2, each split nut 6 linearly moves along the radial direction R on the tie bar 2 side, that is, perpendicular to the tie bar axis P of the tie bar 2. The threaded portion (not shown) of the inner end of the split nut 6 meshes with the threaded portion 2a of the tie bar 2, and the tie bar 2 is fixed to the movable platen (5) by each split nut 6, that is, locked.

FIG. 4 shows a state in which the unlocked state and the locked state shown in FIGS. 2 and 3 are overlapped. In actuality, the link 21 and the split nut 6 are positioned on the back side of the annular sprocket 20 in FIG. Therefore, it is indicated by a dotted line.
The structure of the tie bar fixing body 50 for attaching the ring-shaped sprocket 20 and the link 21 to the movable platen 5 is shown in FIG. FIG. 5 shows the case of one annular sprocket 20 in FIG. 1, and the other annular sprockets 20 have the same structure.
That is, the holding plate 30 is fixed to the movable platen 5 by the mounting screws 31, and the projections 32 are provided on the outer edge of the holding plate 30 so as to be held by the plurality of mounting screws 31 a and protrude toward the split nut side. Yes.

  An annular holding body 33 having an annular shape as a whole is disposed inside the protrusion 32, and the protrusion 32 engages with an annular recess 34 formed on the outer peripheral surface 33 a of the annular holding body 33, so that the annular shape is The holding body 33 is configured to be rotatable through the protrusion 32 and the annular recess 34.

The annular holding body 33 is configured to be fixed to the back surface 20 a of the annular sprocket 20 via an attachment screw 35 and to rotate integrally with the annular sprocket 20.
An outer end 21 a of the link 21 is pivotally supported on the ring-shaped holding body 33 via a first link pin 36, and an inner end 21 b of the link 21 is split inside the ring-shaped holding body 33. Are pivotally supported via second link pins 37.

The split nut 6 is formed with a key groove 40 facing the holding plate 30 side and extending along the radial direction of the tie bar 2, that is, along a direction perpendicular to the tie bar axis P of the tie bar 2. Since the key groove 40 is engaged with a key (not shown) provided on the holding plate 30, the split nut 6 reciprocates (linearly moves) in a direction perpendicular to the tie bar axis P. It is configured to be able to.
The threaded portion 6a at the inner end of the split nut 6 is configured to engage or disengage with the threaded portion 2a on the outer periphery of the tie bar 2.
Therefore, the tie bar fixing body 50 is mainly constituted by the holding plate 30, the ring-shaped sprocket 20, the ring-shaped holding body 33, the link 21, the first and second link pins 36 and 37, and the key groove 40.

Next, the case where the tie bar 2 is fixed and released in the tie bar fixing structure in the injection molding machine mold clamping apparatus of the present invention having the above-described configuration will be described.
First, in the state of FIG. 1, each ring sprocket 20 is rotated by only one endless chain 22 with respect to the four tie bars 2 in the movable platen 5, and each link 21 coincides with the radial direction R of the tie bar 2. In the non-radial direction, that is, in the non-fixed state in which each split nut 6 of each annular sprocket 20 is pulled up along the radial direction R, and the tie bar 2 is fixed by each split nut 6. is there.

In the above-described non-fixed state of the tie bar 2, the tie bar 2 is pulled out from the movable platen 5 as shown in FIG.
In the above-described state, when the mold opening / closing cylinder 3 in FIG. 7 is operated and the movable platen 5 is moved again to the fixed platen 4 side by a predetermined distance, the screw portion 2a at the tip of each tie bar 2 becomes the screw portion 6a of each split nut 6. Are in a state corresponding to each other.

In the above-described state, each link 21 is in the state shown in FIGS. 1 and 2, but in this state, the motor 24, which is only one drive source, is driven to slightly rotate the endless chain 22 in the CCW direction. 1 and 2, each link 21 assumes a posture along the radial direction R of the tie bar 6 as shown in FIG. 3, and the second link pin 37 of the link 21 disengages the split nut 6. By pushing inward, each split nut 6 is guided by the key groove 40 perpendicular to the tie bar axis P of the tie bar 2 and moves linearly, and the threaded portion 6a of each split nut 6 and the threaded portion 2a of the tie bar 2 are moved. Are engaged with each other, whereby each tie bar 2 is fixed to the movable platen 5. Thereafter, the mold opening / closing cylinder 3 draws the movable platen 5 toward the fixed platen 4 side, thereby bringing the mold into a closed state as shown in FIG.
In this state, when the mold clamping cylinder 2A is driven, the movable platen 5 is further drawn toward the fixed platen 4 side to perform mold clamping.

  Like the above-mentioned present invention, the structure which fixes the tie bar 2 using the endless chain 22, the ring-shaped sprocket 20, and each split nut 6 and the split nut 6 consisting of a half nut shown in FIGS. 10 to 13 are used. Compared with the conventional structure, as shown in FIGS. 6 and 14, the split nut 6 releases the mesh with the threaded portion 6 a of the tie bar 2, or along the radial direction R from the release to the mesh, that is, The moving stroke S in the direction perpendicular to the tie bar axis P of the tie bar 2 is 5 mm in the structure of the present invention shown in FIG. 6, whereas it is 15 mm in the conventional structure shown in FIG. S can be significantly shortened, and only one drive source 24 can be used to significantly shorten the moving distance and time associated with the opening and closing of each split nut 6 as compared with the prior art.

  The tie bar fixing structure of the injection molding machine mold clamping device according to the present invention uses an endless chain, a sprocket and four split nuts to fix and release the tie bar, thereby reducing the movement distance and time associated with opening and closing the split nut. The tie bar fixing structure itself can be reduced in size and simplified.

The summary of the tie bar fixing structure in the injection molding machine mold clamping apparatus according to the present invention is summarized as follows.
A fixed plate 4 having a fixed mold 4A and a plurality of tie bars 2 provided on the base 1, a movable plate 5 movable on the base 1 with respect to the fixed plate 4, and provided on the movable plate 5. A tie bar fixing body 50 into which the screw portion 2a at the tip of each tie bar 2 is inserted, and a split nut 6 provided on each tie bar fixing body 50, and the split nut 6 is engaged with the screw portion 2a. In the tie bar fixing structure in the injection molding machine mold clamping apparatus in which the screw portion 2a is fixed to the movable plate 5 by matching, the split nut 6 is composed of four pieces and is connected to the movable plate 5 side. The ring-shaped sprocket 20 is rotatably connected to a ring sprocket 20 through a link 21, and the split nut 6 is connected to the tie bar shaft of the tie bar 2 through the link 21 by the rotation of the ring-shaped sprocket 20. Each split nut 6 is configured to move in a perpendicular direction with respect to P and engage or disengage with the threaded portion 2a. Each annular sprocket 20 includes an endless chain. 22, the endless chain 22 is configured to be driven by only one driving source 24, and the tie bar fixing body 50 includes a holding plate 30 attached to the movable platen 5, A ring-shaped holding body 33 that is rotatably attached to the holding plate 30 and to which the ring-shaped sprocket 20 is fixed, and a first link pin 36 for rotatably connecting the outer end 21 a of the link 21 to the ring-shaped sprocket 20. A second link pin 37 for rotatably connecting the inner end 21b of the link 21 to the split nut 6, and the split nut 6 A key groove 40 for guiding the movement, a protrusion 32 provided on the holding plate 30 and projecting toward the split nut 6, and an outer peripheral surface 33 a of the ring-shaped holding body 33. A ring-shaped recess 34, the protrusion 32 engages with the ring-shaped recess 34, and the ring-shaped holding body 33 and the ring-shaped sprocket 20 are rotatable with respect to the holding plate 30. The movable platen 5 is provided with four holding plates 30 and the ring-shaped sprocket 20.

DESCRIPTION OF SYMBOLS 1 Base 2 Tie bar 2a Thread part 3 Type | mold opening / closing cylinder 4 Fixed board 4A Fixed mold 5 Movable board 5a Corner | angular part 5A Movable mold 6 Split nut 20 Ring-shaped sprocket 21 Link 21a Outer end 21b Inner end 22 Endless chain 23 Guide roller 24 Motor (drive source)
30 holding plate 31 mounting screw 32 protrusion 33 ring-shaped holding body 33a outer peripheral surface 34 ring-shaped recess 35 mounting screw 36 first link pin 37 second link pin 40 keyway S moving stroke R radial direction P tie bar axis

Claims (5)

A stationary platen (4) provided on a base (1) and having a fixed mold (4A) and a plurality of tie bars (2), and movable relative to the stationary platen (4) on the base (1) Movable platen (5), a tie bar fixing body (50) provided on the movable platen (5), into which a screw portion (2a) at the tip of each tie bar (2) is inserted, and each tie bar fixing body (50 A split nut (6) provided in
In the tie bar fixing structure in an injection molding machine mold clamping apparatus configured to fix the screw part (2a) to the movable platen (5) by meshing the split nut (6) with the screw part (2a),
The split nut (6) is composed of four pieces and is connected to a ring-shaped sprocket (20) provided rotatably with respect to the movable platen (5) side via a link (21), and the ring-shaped sprocket (20 ) Rotation causes the split nut (6) to move perpendicularly to the tie bar axis (P) of the tie bar (2) via the link (21), and the split nut (6) A tie bar fixing structure in a mold clamping device of an injection molding machine, characterized in that the part (2a) is engaged or disengaged.   The ring-shaped sprockets (20) are connected by an endless chain (22), and the endless chain (22) is driven by only one drive source (24). The tie bar fixing structure in the injection molding machine mold clamping apparatus described.   The tie bar fixing body (50) includes a holding plate (30) attached to the movable platen (5), and a ring-shaped holding member that is rotatably attached to the holding plate (30) and to which the ring-shaped sprocket (20) is fixed. A body (33), a first link pin (36) for rotatably connecting the outer end (21a) of the link (21) to the annular sprocket (20), and an inner end of the link (21) A second link pin (37) for rotatably connecting (21b) to the split nut (6), and for guiding the straight movement of the split nut (6) provided on the split nut (6); The tie bar fixing structure in an injection molding machine mold clamping apparatus according to claim 1 or 2, further comprising a key groove (40).   A protrusion (32) provided on the holding plate (30) and projecting toward the split nut (6), and an annular recess (34) formed on the outer peripheral surface (33a) of the annular holder (33). The protrusion (32) engages with the annular recess (34), and the annular holder (33) and the annular sprocket (20) are configured to be rotatable with respect to the holding plate (30). A tie bar fixing structure in an injection molding machine mold clamping apparatus according to claim 3.   The tie bar in an injection molding machine mold clamping apparatus according to claim 3 or 4, wherein the movable plate (5) is provided with four holding plates (30) and an annular sprocket (20). Fixed structure.

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