JPH09277331A - Clamping equipment of precision injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress torsional deformation of a fixed die plate on the occasion when tie bars are fastened and fixed to the fixed die plate by nuts. SOLUTION: External thread parts 29a in the end parts on the fixed die plate 15 side of four tie bars connecting a fixed die plate 15 retaining a cavity side part with a clamping cylinder retaining a force side part are fastened and fixed by nuts 31. Fastening directions of the nuts 31 at separate fastening parts LU, RU, RD and LD are different from each other between the ones being adjacent along the peripheral edge part of the fixed die plate 15. Moments MLU, MRU, MRD AND MLD, made to act on the fixed die plate 15 by the fastening are also different between the adjacent ones and these moments MLU, MRU, MRD, AND MLD cancel each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed die plate for holding a fixed mold and a cylinder body of a mold clamping cylinder for performing a mold clamping operation by moving a movable mold close to the fixed mold during mold clamping. The present invention relates to a mold clamping device of a precision injection molding machine connected by a tie bar that receives a mold clamping reaction force.

[0002]

2. Description of the Related Art Generally, a mold clamping device of a precision injection molding machine is
A fixed die plate that holds a fixed die, a moving die plate that holds a moving die, and a die clamping cylinder that presses the moving die against the fixed die to perform a die clamping operation on the apparatus body frame. Each is installed. The mold clamping cylinder is equipped with a mold clamping ram, the tip of which is fixed to the moving die plate. The cylinder body and the fixed die plate, in which the mold clamping ram is slidably accommodated, are arranged at the four corners of the fixed die plate. The moving die is pressed against the fixed die by the four tie bars that are connected and the moving die is in close contact with the fixed die, so that the moving die is pressed against the fixed die, and as a reaction force, tension is applied to the tie bar. It will be given and the mold clamping operation will be performed.

FIG. 3 is a side view of the mold clamping device as seen from the fixed die plate 1 side.
Is a support leg 5a of the pedestal 5 installed on the molding machine main body frame 3 at substantially the center in the vertical direction on both sides thereof.
Is supported at the upper end of. The fixed die plate 1 is formed in a rectangular shape, and the tie bars 7 arranged at the four corners of this rectangular portion are fastened and fixed by nuts 9. The fastening directions of the four nuts 9 are all clockwise in the figure by arrows A in the same direction.

[0004]

By the way, as described above, when the fastening directions of the four nuts 9 are all the same as indicated by the arrow A, the fixed die plate 1 is indicated by the broken arrow B in FIG. As shown, a clockwise moment is received as a whole, and a clockwise twisting deformation occurs,
Assembling accuracy tends to deteriorate, such as difficulty in obtaining parallelism of the fixed die plate 1. Such deterioration of assembly accuracy
The precision injection molding machine that manufactures optical discs such as compact discs and digital video discs, for which high precision is required, also affects defective dies and causes defective products.

Therefore, an object of the present invention is to suppress torsional deformation of the fixed die plate when the tie bar is fastened to the fixed die plate by a fastener.

[0006]

In order to achieve the above object, the present invention is, firstly, to fix a fixed die plate for holding a fixed die and a movable die close to the fixed die to perform mold clamping. In a mold clamping device of a precision injection molding machine, in which a cylinder body of a mold clamping cylinder that operates is connected by a tie bar that receives a mold clamping reaction force at the time of mold clamping, the tie bar includes a fixed mold and a movable mold. A plurality of them are arranged on the outer peripheral side, and the ends of the tie bars on the fixed die plate side are
It becomes a screw part, penetrates the fixed die plate, and is fastened and fixed by a fastener, and a plurality of fastening parts by the screw part and the fastener have different fastening rotation directions.

Secondly, in the first construction, the fixed die plate is formed in a rectangular shape, and tie bars are connected to the four corners of the rectangular shape, and the fastening rotation direction at each fastening portion of the four corners is the same as that of the fixed die plate. Those adjacent to each other along the peripheral edge are different from each other.

Thirdly, in the first configuration or the second configuration, the fastening portion is composed of a male screw portion formed at the end of the tie bar and a nut screwed to the male screw portion.

According to the mold clamping device of the precision injection molding machine having such a configuration, the fastening rotation directions at the fastening portions when fixing the plurality of tie bars to the fixed die plate are different from each other. The fixed die plate as a whole does not receive a moment in the same direction due to the fastening of the respective fasteners, and the twisting deformation of the fixed die plate is suppressed.

The fixed die plate is formed in a rectangular shape, and the fastening rotation directions of the fastening portions at the four corners are made different from each other along the peripheral edge portion of the fixed die plate so that the fixed die plate is twisted and deformed. Is further suppressed.

[0011]

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

FIG. 1 is a front view of a mold clamping device of a precision injection molding machine according to an embodiment of the present invention, and FIG. 2 is a right side view of FIG. This mold clamping device is a molding machine body frame 1
A pedestal 13 is installed on the base 1, and a fixed die plate 15 formed in a rectangular shape, a movable die plate 17, and a mold clamping cylinder 19 are provided on the pedestal 13. The mold clamping cylinder 19 is housed so as to be movable in the left-right direction in FIG.
7 is fixed to the die clamping ram 23, and the fixed dies 25 and the movable dies 27 are respectively held by the die plates 15 and 17 so as to face each other.

The cylinder body 21 of the mold clamping cylinder 19 and the fixed die plate 15 are composed of four pieces arranged at positions corresponding to the four corners of the fixed die plate 15 on the outer peripheral sides of the fixed die 25 and the movable die 27. It is connected and fixed by a tie bar 29. Fixed die plate 15 for each tie bar 29
The side end has a small diameter and is inserted into the insertion hole 15a,
A male screw portion 29a at the tip projects to the opposite side, and a nut 31 as a fastener is fastened to this projecting end.

The four nuts 31 are, as shown in FIG.
The fastening rotation directions are such that those adjacent to each other along the peripheral edge of the fixed die plate 15 are different from each other. That is, in the rectangular fixed die plate 5 in FIG. 2, the fastening rotation directions of the nuts 31 that are diagonally opposed to each other are the same, and here, the lower right one and the upper left one in FIG. , Which constitute the right-handed fastening portions RD, LU shown by the arrow R, and the upper-right and left-handed fastening portions RU, LD, shown by the arrow L, show the left-handed fastening with the left-hand thread. Are configured.

On the other hand, similarly, the end of the diver 29 on the side of the mold clamping cylinder 19 has a small diameter and is inserted into an insertion hole (not shown), and a male screw portion 29b formed at the tip protrudes to the opposite side. A nut 33 is fastened to the end portion. The fastening rotation direction of the nut 33 fastened to the mold clamping cylinder 19 side is the fastening portion in the same direction as the corresponding male screw portion 29a. That is, for the tie bar 29 in which the male screw portion 29a has a right-hand thread, the male screw portion 29b also has a right-hand thread, and
For a tie bar 29 having a left-hand thread 9a, a male thread portion 29b is provided.
Is also as a left-hand thread.

The pedestal 13 has a bottom surface portion 35 and the bottom surface portion 3
5, the fixed die plate 1 is erected at the right end in FIG.
5, a pair of fixed die supporting legs 37 for supporting both left and right sides in FIG. 2 and a bottom portion 35 standing upright at the left end in FIG.
The mold clamping cylinder 19 is provided with a pair of cylinder support legs 39 that support both left and right sides.

As shown in FIG. 2, sliding protrusions 15b are formed on both sides of the fixed die plate 15 at a substantially central position in the vertical direction, while upper ends of a pair of fixed die support legs 37 are opposed to each other. A sliding groove 37a extending in the left-right direction in FIG. 1 and into which the sliding protrusion 15b slidably enters is formed in the portion. The sliding groove 37a is formed by an L-shaped holding bracket 43 fixed to the upper end of the fixed die support leg 37 with a bolt 41. Sliding protrusion 1
5b, a sliding plate 45 made of a sintered material impregnated with oil is attached to the lower surface, and is placed on the fixed die supporting leg 37 via this sliding plate 45 to provide sliding resistance to the fixed die supporting leg 37. Is decreasing. A joint surface 47 between the lower surface of the sliding plate 45 and the upper surface of the fixed die support leg 37 is aligned with the vertical center position of the fixed die plate 15.

On the other hand, the mold clamping cylinder 19 has a cylinder support 21a in a cylinder body 21, and fixing projections 21b are formed on both side portions of the cylinder support 21a at a substantially central position in the vertical direction, and the lower surface of the fixing projection 21b. The upper end of the cylinder supporting leg 39 is fixed to the cylinder by a bolt 49. The lower surface of the fixed protrusion 21b and the cylinder support leg 39
The joint surface 51 with the upper surface of the mold is aligned with the vertical center position of the mold clamping cylinder 19.

That is, the fixed die plate 15 and the mold clamping cylinder 19 are both supported by the pedestal 13 on the side of the molding machine body frame 1 at the central position in the vertical direction.

The movable die plate 17 has a pedestal 13 at the lower end.
It moves via the linear guide mechanism 53 with respect to. The linear guide mechanism 53 is provided on the bottom surface portion 35 of the pedestal 13 and is provided at the lower center of the moving die plate 17 by inserting the guide rail 55 extended in the moving direction of the moving die plate 17 and the guide rail 55. Support protrusion 17
a Linear bearings 57 at the lower end are provided. A roller (not shown) is provided on the side of the linear bearing 57, and this roller rotates on the guide rail 55 as the movable die plate 17 moves. That is, the load of the movable die plate 17 is received by the linear guide mechanism 53.

The movable die plate 17 has mounting bracket portions 17b and 17c projecting upward and downward, respectively, at the upper left and lower right in FIG. On the other hand, the cylinder body 59a of the mold opening / closing cylinder 59 is attached to the upper end surface and the lower end surface of the cylinder support 21a of the cylinder body 21 of the mold clamping cylinder 19 at the positions corresponding to the mounting bracket portions 17b and 17c, respectively. . The rod 59b housed so as to be movable in the left-right direction in FIG. 1 from the cylinder body 59a has its tip at the mounting bracket portion 17b of the movable die plate 17.
And 17c, respectively. That is, the movable die plate 1 is moved by the operation of the two mold opening / closing cylinders 59.
7 moves toward and away from the fixed die plate 15.

In the mold clamping device of the precision injection molding machine as described above, first, by the operation of the mold opening / closing cylinder 59,
The movable die plate 17 moves toward the fixed die plate 15 together with the mold clamping ram 23, and the movable die 27 comes into close contact with the fixed die 25. By operating the mold clamping cylinder 19 in this state, the movable mold 27 is pressed against the fixed mold 25 and the mold clamping operation is completed.

The reaction force of the mold clamping force generated during the mold clamping operation described above is stretched and deformed by the four tie bars 29 supporting it.
With the extension deformation of the tie bar 29, the fixed die plate 15 follows the extension deformation operation of the tie bar 29 by the sliding protrusion 15b sliding on the sliding groove 37a of the fixed die support leg 37.

In the mold clamping device for performing such a mold clamping operation, the fastening portion of the tie bar 29 on the fixed die plate 15 side is, as shown in FIG. 2, a nut that is adjacent along the peripheral edge of the fixed die plate 15. 31 The fastening rotation directions are different from each other, and the moments M _LU , M _RU , M _RD and M _LD indicated by broken line arrows corresponding to the fastening portions LU, RU, RD and LD exerted on the fixed die plate 15 by this fastening. Similarly, the adjacent ones are also different from each other, and these moments M _LU , M _RU , M _RD , and M _LD cancel each other out. Also, regarding the nut 33 of the cylinder main body 21 that corresponds to the nut 31 and has the same fastening rotation direction,
Similar moments cancel each other out in the cylinder body 21.

As described above, the moments M _LU , M _RU , M _RD , and M exerted on the fixed die plate 15 and the cylinder body 21 by fastening the four nuts 31 and the nuts 33.
_{Since the LDs} cancel each other out, the torsional deformation of the fixed die plate 15 and the entire cylinder body 21 due to the fastening of the nuts 31 and 33 is suppressed. Therefore, the parallelism between the fixed die plate 15 and the cylinder body 21, and the perpendicularity between the diver 29 and the fixed die plate 15 are likely to be obtained, and as a result, the parallelism between the fixed die plate 15 and the movable die plate 17 is easily obtained. , Which is effective in precision injection molding machines that manufacture optical discs such as compact discs and digital video discs, in which the assembly precision is improved and adverse effects on the mold are avoided, and particularly high precision is required. Becomes

[0026]

As described above, according to the present invention, the fastening rotation directions at the fastening portions when fastening a plurality of tie bars to the fixed die plate are different from each other. The fixed die plate does not receive a moment in the same direction as a whole when the tools are fastened, and the twisting deformation of the fixed die plate can be suppressed.

The fixed die plate is twisted by making the fixed die plate rectangular so that the fastening rotation directions at the fastening portions at its four corners are different from each other along the peripheral edge of the fixed die plate. The deformation can be further suppressed.

[Brief description of drawings]

FIG. 1 is a front view of a mold clamping device of a precision injection molding machine according to an embodiment of the present invention.

FIG. 2 is a right side view of FIG.

FIG. 3 is an operation explanatory view showing a generation state of a moment exerted on a fixed die plate by fastening a nut in a die clamping device of a conventional precision injection molding machine.

[Explanation of symbols]

 11 Device Main Body Frame 19 Clamping Cylinder 21 Cylinder Main Body 25 Fixed Mold 27 Moving Mold 29 Tie Bar 29a Male Thread Part 31 Nut (Fastening Tool) LU, RU, RD, LD Fastening Part

Claims (3)

[Claims] 1. A fixed die plate for holding a fixed mold and a cylinder body of a mold clamping cylinder for performing a mold clamping operation by bringing a movable mold close to the fixed mold, and a mold clamping anti-clamping process at the time of mold clamping. In a mold clamping device of a precision injection molding machine connected by a tie bar that receives a force, a plurality of the tie bars are arranged on the outer peripheral side of the fixed mold and the moving mold, and the end of each tie bar on the fixed die plate side. The portion becomes a threaded portion, penetrates the fixed die plate, and is fastened and fixed by a fastener, and the plurality of fastening portions by the screw portion and the fastener are:
A mold clamping device for a precision injection molding machine, characterized in that it is provided with different fastening rotation directions. 2. The fixed die plate is formed in a rectangular shape, and tie bars are connected to the four corners of the rectangular shape, and the fastening rotation directions of the fastening portions at the four corners are adjacent to each other along the peripheral edge portion of the fixed die plate. The mold clamping device of the precision injection molding machine according to claim 1, wherein the molds are different from each other. 3. The precision injection molding machine according to claim 1, wherein the fastening portion is composed of a male screw portion formed at an end portion of the tie bar and a nut screwed to the male screw portion. Mold clamping device.