JP2001079911A - Mold clamping device for injection molding machine and actuation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously realize high speed opening/closing and a high pressure clamping of a mold by obtaining a high drive speed and a large drive force for a movable platen by means of a ball screw mechanism. SOLUTION: A first ball screw nut 32 and a cylindrical body 12 for opening/ closing a mold are integrally moved in an axial direction by rotating to drive a first ball and thread shaft 20 by a first drive means 24 and, in turn, a movable platen 14 fixed to the cylindrical body 12 is actuated to open/close the mold. On the other hand, second ball and screw shafts 34, 34 are rotated to drive by a second drive means 48 under such a state that a mold clamping member 40 and the cylindrical body 12 are engaged with each other by engaging means 64, 66 at a position where the mold is clamped by the movable platen 14. Thus second ball screw nut 36, 36, the mold clamping member 40 and the cylindrical body 12 are integrally moved in the axial direction to make the movable platen 14 clamp the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device for an injection molding machine and an operation control method thereof, and more particularly, to opening and closing and clamping a mold by driving a movable platen using a ball screw mechanism. The present invention relates to a mold clamping device in an injection molding machine and an advantageous operation control method thereof.

[0002]

2. Description of the Related Art Conventionally, a mold clamping device used in an injection molding machine includes a direct pressure type in which a driving force such as opening and closing of a mold and mold clamping is applied directly to a movable platen by a hydraulic cylinder mechanism. In addition to a toggle type in which a motor is indirectly operated via a link mechanism, a ball screw mechanism that converts a rotational driving force of a motor into a reciprocating driving force to operate is known. ing.

[0003] A mold clamping device using this ball screw mechanism generally has a ball screw shaft which is immovably and rotatably arranged in the axial direction and is driven to rotate by a motor or the like. A ball screw nut fixedly mounted on a movable platen moving member having a movable platen attached to an axial end portion thereof is axially moved together with the movable platen moving member in the axial direction without rotating. Therefore, the movable plate approaches the fixed plate located in front of the moving direction /
It separates and opens and closes and molds the dies mounted on the movable platen and the fixed platen. Compared with a mold clamping device using a hydraulic cylinder mechanism or a link mechanism, the mold is closed. The mold opening / closing operation and the mold clamping operation of the mold can be easily performed with a relatively simple and compact structure.

However, in a conventional mold clamping device utilizing such a ball screw mechanism, in order to obtain an excellent molding cycle and a high molding accuracy, injection molding of a target molded product is required. It was difficult to balance the two functions performed.

That is, generally, in a mold clamping device of an injection molding machine, in order to shorten the molding cycle by opening and closing the mold at a high speed, a large driving speed for the movable platen is exhibited during the mold opening and closing operation. It is required that a large driving force be exerted on the movable plate during the mold clamping operation in order to ensure excellent molding accuracy due to the high pressure clamping of the mold. In the conventional mold clamping device as described above, which performs clamping and mold clamping, for example, when the lead of the ball screw shaft is reduced in order to increase the driving force on the movable plate, the mold closing operation In this case, the drive speed for the movable plate is inevitably reduced, and conversely, if the lead of the ball screw shaft is increased, the drive speed for the movable plate is increased. Becomes the driving force for the movable platen is reduced, therefore, to increase the driving speed and the driving force for the movable platen at the same time, is the been extremely difficult.

[0006]

Here, the present invention has been made in view of the above-mentioned circumstances, and a problem to be solved is to drive a movable platen using a ball screw mechanism. In a mold clamping device of an injection molding machine that performs mold opening and closing and mold clamping, it is possible to reliably obtain both a large driving speed and a large driving force for a movable platen. It is an object of the present invention to provide an improved structure so that both can be advantageously realized. Another object of the present invention is to provide an advantageous operation control method for such an improved mold clamping device.

[0007]

According to the present invention, in order to solve such a problem, (a) a first ball screw shaft having a fixed position rotatable around a central axis; and (b) the first ball screw shaft. A first driving means for driving the screw shaft to rotate; and (c) a movable plate attached to the first ball screw shaft so as to be externally mounted on the first ball screw shaft so as to be non-rotatable around the central axis. A mold opening / closing tubular body movable in the direction of the central axis;
While being screwed to the first ball screw shaft and fixed to the mold opening / closing tubular body, the mold opening / closing tubular body is rotated with the rotation of the first ball screw shaft. A first ball screw nut that moves in the direction of the central axis, and (e) rotatable about the central axis and immovable in the direction of the central axis in a state of extending parallel to the central axis of the first ball screw shaft. (F) second driving means for rotating and driving the second ball screw shaft;
(G) a mold-clamping member movably provided in the central axis direction of the mold opening / closing tubular body and capable of being locked to the mold opening / closing tubular body; By being screwed to the ball screw shaft and being fixed to the mold clamping member,
A second ball screw nut for moving the mold clamping member in the direction of the center axis of the mold opening / closing tubular body with the rotation of the second ball screw shaft; and (i) the mold clamping member. This is provided by interposing the mold clamping member and the mold opening / closing tubular body between the mold opening / closing tubular body and the mold opening / closing tubular body, thereby enabling integral movement thereof. The gist of the present invention is a mold clamping device for an injection molding machine, which has a locking means for causing the movement of the mold clamping member to be exerted as a mold clamping force by the mold opening / closing tubular body.

[0008] In short, in the mold clamping device of the injection molding machine according to the present invention, the first ball screw shaft is rotated by the first driving means, and the first ball screw nut and the mold opening / closing unit are opened and closed. By moving the cylindrical body integrally with the mold opening / closing cylindrical body in the central axis direction,
The forward / backward movement (drive) of the movable platen between the mold opening position and the mold closing position is performed. Further, at the mold closing position of the movable platen, the mold clamping member and the mold opening / closing tubular body are mutually locked by the locking means, so that the mold clamping member and the mold opening / closing tubular body are joined together. The second ball screw shaft is rotationally driven by the second driving means in a state in which the second ball screw nut can be integrally moved, and the second ball screw nut and the mold clamping member are integrally opened and closed. The mold opening / closing tubular body is moved in the central axis direction together with the mold clamping member by moving the mold opening / closing tubular body in the central axis direction. Driving) is performed.

Therefore, in such a mold clamping device, for example, the first ball screw shaft on which the first ball screw nut for performing the forward / backward operation of the movable plate is formed with a large lead. The second ball screw shaft on which the second ball screw nut for performing the operation of pressing / depressing the movable platen can be formed with a lead smaller than the first ball screw shaft. Accordingly, while effectively increasing the driving speed of the movable platen during the mold opening / closing operation, the movable platen is particularly subjected to the pressing / depressing operation, that is, the mold clamping / depressing operation. The driving force on the movable platen at the time can also be increased very advantageously.

Therefore, in the mold clamping device of the injection molding machine according to the present invention, high-speed opening and closing of the mold and high-pressure clamping can be simultaneously realized by a simple and compact ball screw mechanism. As a result, the molding cycle can be effectively shortened, and the molding accuracy can be extremely advantageously improved.

According to one preferred embodiment of the mold clamping device in the injection molding machine according to the present invention as described above, the locking means moves in the axial direction with respect to the outer peripheral surface of the mold opening / closing tubular body. A large number of locking teeth formed at regular intervals, each extending in the circumferential direction, and are supported so as not to be able to move in the axial direction with respect to the mold clamping member, and with respect to the outer peripheral surface of the cylindrical body for opening and closing the mold. A locking block provided with engaging teeth which are displaced in the approaching / separating direction so as to be locked / removed with respect to the locking teeth of the mold opening / closing tubular body. In the mold clamping device having such a configuration, the mold opening / closing tubular body and the mold clamping member are moved over a wide range of the axial relative position of the mold opening / closing tubular body with respect to the mold clamping member. Thus, they can be mutually locked, whereby the range of the mold thickness of the mold that can be mounted can be effectively widened. Also,
In such a mold clamping apparatus, the mold opening / closing tubular body and the mold clamping member can be reliably locked with a large locking strength, and the engagement between the mold opening / closing tubular body and the mold clamping member can be ensured. Suspension and release can also be performed quickly.

According to the present invention, there is provided a mold for an injection molding machine, which further has a configuration according to a preferred embodiment as described above, in order to solve the problem relating to the operation control method of the mold clamping device in the injection molding machine. When performing a mold clamping operation in the clamping device, the mold opening / closing tubular body at a mold closing completion position in a state where a model mold having a reference minimum mold thickness having a mold thickness smaller than at least a mold to be attached is attached. The axial position of is set as the mold position reference origin, and at this mold closing completion position,
Adjusting the axial position of the mold-clamping member in the center axis direction of the mold opening / closing cylinder so that the meshing teeth of the engagement block can be engaged with the engagement teeth of the mold opening / closing cylinder. Based on the mold position reference origin and the position data of the mold clamping member position reference point, based on the position data of the mold position reference point and the mold closing completion position when a mold having an arbitrary mold thickness is mounted, The axial position of the mold-clamping member in the center axis direction of the mold opening / closing cylinder so that the meshing teeth of the engagement block can be engaged with the engagement teeth formed on the mold opening / closing cylinder. An operation control method of a mold clamping device in an injection molding machine characterized by adjusting
This is the gist.

According to the operation control method of the mold clamping device in the injection molding machine according to the present invention, immediately and reliably at the time of completion of the mold closing operation regardless of the size of the mold thickness. Since the mold clamping member and the mold opening / closing tubular body can be mutually locked by the locking means, the molding cycle can be further shortened and the like can be more advantageously achieved. is there.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, in order to clarify the present invention more specifically, a configuration of a mold clamping device and an operation control method thereof in an injection molding machine according to the present invention will be described in detail with reference to the drawings. It will be explained.

First, FIGS. 1 to 3 schematically show an example of a mold clamping device in an injection molding machine having a structure according to the present invention. As is apparent from those figures, such a mold clamping device includes a mold opening / closing cylinder 12 supported by a base 10 and movable in an axial direction extending in a horizontal direction. A movable platen 14 is fixedly provided at the axial end of the cylindrical body 12. And
As the mold opening / closing cylinder 12 is reciprocated in the axial direction, the movable plate 14 is reciprocated in the approaching / separating direction with respect to a fixed plate (not shown) arranged opposite to the movable plate 14. The movable mold and the fixed mold (both not shown) attached to the board 14 and the fixed board are designed to be closed / opened. Further, as is well known, the movable platen 14 is structured to be guided in a moving direction by a plurality of guide rods (tie bars) 16 protruding from a fixed platen. In the following description, with reference to the moving direction of the movable platen 14, the left side in FIG. 1 is referred to as a retreating side, and the right side in FIG.

More specifically, the mold clamping device of the present embodiment comprises:
The first ball screw shaft 20 extending in the horizontal axis direction is supported by a bracket 18 erected on the base 10 at one end (the left end in FIG. 1) of the first ball screw shaft 20 via a bearing. Thereby, it is arranged so as to be rotatable around the central axis and immovable in the axial direction. The first ball screw shaft 20 has a sufficient length protruding from the position where it is supported by the bracket 18 toward one side in the axial direction (the right side in FIG. 1), while the ball screw shaft 20 The end of the shaft 20 on the bracket 18 support side is the bracket 18
From which the toothed pulley 22 is mounted. A first servomotor 24 as first driving means is fixed to the bracket 18. A toothed pulley 26 attached to an output shaft of the first servomotor 24 and a first servomotor 24 The first ball screw shaft 20 is rotated and controlled by a first servomotor 24 via a toothed belt 28 stretched between the pulley 22 and a toothed pulley 22 attached to the ball screw shaft 20. It is supposed to be.

In the first ball screw shaft 20, one side in the axial direction from the bracket 18 (in FIG. 1,
A mold opening / closing cylinder 12 as a mold opening / closing tubular body having a substantially cylindrical shape as a whole is externally inserted into and supported by the projecting portion (right side). That is, the mold opening / closing cylinder 12 is provided with the first ball screw shaft 2.
0, extending outwardly in the radial direction to cover the outer peripheral surface of the protruding portion of the ball screw shaft 20, and supporting the tip ends of a plurality of guide rods 16 extending from the fixed plate. Holder plate 3 fixed to base 10
In a state where the first ball screw shaft 20 is disposed so as to penetrate the center portion of the first ball screw shaft 20, the first ball screw shaft 20 is supported so as to be axially displaceable relative to the ball screw shaft 20. .

Further, in the mold opening / closing cylinder 12, the movable plate 14
Is fixed via a spacer block 15, and the first ball screw shaft 2
The first ball screw nut 32 screwed to 0 is screwed and fixed by a screw (not shown) or the like.
That is, the movable platen 14 is positioned so as to be able to move integrally with the mold opening / closing cylinder 12 between the holder plate 30 and a fixed plate (not shown), and the first ball screw nut 32 is attached to the mold opening / closing cylinder. By being fixed to the body 12,
It is movable in the axial direction together with the mold opening / closing cylinder 12, and is supported so as not to rotate around the central axis.

Thus, by rotating the first ball screw shaft 20 in the forward and reverse directions by the first servo motor 24, the first ball screw nut 32 screwed to the first ball screw shaft 20 is rotated. The mold opening / closing cylinder 12 can be moved forward / backward in the axial direction based on the screw feed action.
By the forward / backward movement of 2, the movable plate 14 attached to the forward-side end surface of the mold opening / closing cylinder 12 is driven forward / backward (moved), so that the mold opening / closing operation can be performed. -ing In addition, of the forward / backward movement of the mold opening / closing cylinder 12, the backward movement, that is,
The opening operation of the mold is performed by the guide housings 60, 60 of locking mechanisms 56, 56 of the spacer block 15 attached to the rear surface of the movable plate 14 (the surface on the retreat side of the mold opening / closing cylinder 12). Is regulated by the abutment.

As is clear from FIGS. 2 and 3,
With the mold opening / closing cylinder 12 in between, on both sides,
The second ball screw shafts 34 are provided one by one. The two second ball screw shafts 34, 34
As shown in FIG. 1, a thread having a lead smaller than the thread of the first ball screw shaft 20 is engraved on the outer peripheral surface of a substantially half portion on one side in the axial direction,
The outer peripheral surface of the remaining portion on the other side in the axial direction is a smooth surface. And each of these second ball screw shafts 3
4, 34, both sides of the mold opening / closing cylinder 12 extend in the horizontal axis direction, and the other end in the axial direction is supported by the holder plate 30 via a bearing. Accordingly, the first ball screw shaft 20 inserted in the mold opening / closing cylinder 12 is disposed so as to be rotatable about the central axis and immovable in the axial direction in a state extending in parallel with the central axis. It is being done.

The second ball screw shafts 34, 3
4, the second ball screw nuts 36, 36 are screwed one by one, and the second ball screw nuts 36, 36 are further connected to the second ball screw shafts 34, 3 respectively.
4 is fixed to the mold clamping plate 38 which is arranged opposite to the holder plate 30 which supports the screw 4 by screws or the like (not shown). The mold clamping plate 38 is inserted into the large-diameter hole provided in the center so that the mold opening / closing cylinder 12 does not contact the inner peripheral surface of the large-diameter hole. The two second ball screw shafts 34, 34 are respectively inserted into the small diameter holes formed on both sides of the diameter hole so as not to contact the inner peripheral surface of each small diameter hole. The second balls screwed to the respective second ball screw shafts 34, 34 are positioned so as not to rotate about the center axis of one ball screw shaft 20 and to be movable in the axial direction. The screw nuts 36, 36 are respectively made non-rotatable and the second ball screw shafts 34, 34
Is rotated along with the mold clamping plate 38 in the axial direction of the second ball screw shafts 34, 34.

On the other hand, between the second ball screw shafts 34, 34, a mold clamping cylinder 40 as a mold clamping member is disposed. The mold clamping cylinder 40 is a mold opening / closing cylinder 1.
2 and a cylindrical shape having an axial length shorter than the mold opening / closing cylinder 12 and a mold opening / closing cylinder between the second ball screw shafts 34, 34. 1
2, a guide bush 42 which is externally inserted so as not to contact the outer peripheral surface thereof and is fixedly mounted inside an insertion hole through which the mold opening / closing cylinder 12 of the holder plate 30 is inserted. It is slidably interpolated and fitted to it. Then, the mold clamping cylinder 4
0 is the mold clamping plate 38 under such an arrangement state.
The second ball screw nuts 36, 36 are fixed by screws to the surface opposite to the side to which the second ball screw nuts 36, 36 are fixed.

The outer peripheral surface of each of the second ball screw shafts 34, 34 has a smooth surface.
4, 44 are attached and fixed, respectively. A second servomotor 48 as a second driving means is fixed to the holder plate 30 via a bracket 46, and is attached to an output shaft of the second servomotor 48. Toothed pulley 50,
A tension pulley 52 provided on the opposite side of the second servomotor 44 with the toothed pulleys 44, 44 attached to the second ball screw shafts 34, 34 and the mold opening / closing cylinder 12 therebetween. The second ball screw shafts 34, 34 are rotationally driven and controlled by the second servomotor 48 via the toothed belt 54 stretched between them.

Therefore, here, the second ball screw shaft 3
The first and second servomotors 24 rotate and control the rotation of the first and second servomotors 24 in the forward and reverse directions, so that the second ball screw nut 3 screwed to the second ball screw shafts 34 and 34.
6 and 36, the clamping plate 38
The mold clamping cylinder 40 is moved forward / backward in the axial direction of the second ball screw shafts 34, 34, and the movement can be controlled. Here, the retracting movement of the mold clamping plate 38 and the mold clamping cylinder 40 is performed by the guide housings 60, 60 of locking mechanisms 56, 56, which will be described later, attached to the tip of the mold clamping cylinder 40. It is regulated by the contact with the holder plate 30. The forward movement of the mold clamping plate 38 and the mold clamping cylinder 40 moves the mold clamping plate 38 against a stopper projection (not shown) provided on the surface of the holder plate 30 facing the mold clamping plate 38.
Is regulated by the abutment.

Further, a locking mechanism 56 as locking means is mounted on a tip portion of the mold clamping cylinder 40 opposite to the side fixed to the mold clamping plate 38. The locking mechanism 56 includes a pair of semi-cylindrical half nuts 58 as locking blocks, which are disposed to face each other in the radial direction.
58, and their half nuts 58, 58
The guide housing 6 fixed to the mold clamping cylinder 40
By 0 and 60, the mold clamping cylinder 40 is supported so as not to move in the axial direction and to be displaceable in the radially opposite direction. Then, the pair of half nuts 58, 58 are driven by the drive cylinder mechanisms 62, 62 fixed to the guide housings 60, 60 to reciprocate in the approaching / separating direction with respect to the mold opening / closing cylinder 12. That can be done.

The pair of half nuts 58, 5
On the inner peripheral surface of 8 (the surface facing the outer peripheral surface of the mold opening / closing cylindrical body 12), a plurality of meshing teeth 64 continuously extending in the circumferential direction with a sawtooth cross section are provided at equal intervals in the axial direction. Is formed. Furthermore, the pair of half nuts 58,
On the outer peripheral surface of the mold opening / closing cylinder body 12 where the inner peripheral surface of the mold 58 is opposed, a sawtooth-shaped cross section having a cross-sectional shape corresponding to the meshing teeth 64 formed on the half nut 58 extends continuously in the circumferential direction. Numerous stop teeth 66 are formed at equal intervals in the axial direction. Note that the axial pitches (formation intervals) of the meshing teeth 64 and the locking teeth 66 are set to be the same as each other, and both are set at constant intervals in the axial direction.

Then, a pair of half nuts 58, 58
Are held at the retracted positions (positions radially outwardly separated from the mold opening / closing cylinder 12) by the drive cylinder mechanisms 62, 62, respectively.
0 is in a free state detached from the mold opening / closing cylinder 12, so that the mold opening / closing cylinder 12 can be freely moved in the axial direction without being limited by the mold clamping cylinder 40. It has become.

On the other hand, the mold opening / closing cylinder 12 is moved forward in the axial direction to a certain extent, and the locking teeth 66 formed on the outer peripheral surface of the mold opening / closing cylinder 12 are placed inside the half nut 58. After being positioned, a pair of half nuts 58,
By driving each of the half nuts 58 to a projecting position (a position close to the mold opening / closing cylinder 12) by the driving cylinder mechanisms 62, 62, the meshing teeth 64 formed on the inner peripheral surfaces of the half nuts 58, 58 are moved. The locking teeth 66 formed on the outer peripheral surface of the mold opening / closing cylinder 12 are engaged with each other. As a result, the mold clamping cylinder 40
Are locked via the locking mechanism 56 so as to be relatively immovable in the axial direction with respect to the mold opening / closing cylinder 12, so that they are integrated. In the present embodiment, a sensor 68 such as a limit switch for detecting whether the half nut 58 is in a locked state or a non-locked state with respect to the mold opening / closing cylinder 12 based on the position of the half nut 58. Is provided.

Therefore, in the present embodiment, the second servomotor 4 is locked under the locking state by the locking mechanism 56.
When the mold 8 is driven, the mold clamping cylinder 40 and the mold opening / closing cylinder 12 are integrally moved forward / backward, and in particular, the mold clamping cylinder 40 and the mold opening / closing cylinder are moved. By the forward movement integrally with the body 12, the mold clamping force is exerted on the movable plate 14 attached to the mold opening / closing cylinder 12.

By the way, the mold opening / closing operation and the mold clamping operation in the mold clamping device having the above-mentioned structure are performed, for example, as follows.

That is, as shown in FIG. 1, when performing the mold closing operation from the mold opening state of the mold holding the mold opening / closing cylinder 12 at the retracted position, first, the first servo motor 24 is used. Is rotated forward, and the first ball screw shaft 2
The mold closing operation is performed by rotating the 0 to move the mold opening / closing cylinder 12 forward and moving the movable platen 14 closer to a fixed platen (not shown). At this time, since the first ball screw shaft 20 is configured to have a large lead, a large forward drive speed of the mold opening / closing cylinder 12 is obtained, and the mold closing operation is performed at a high speed. It will be.

Subsequently, when the mold closing operation is completed, the drive cylinder mechanisms 62, 62 are operated to drive the pair of half nuts 58, 58 to protrude, and the half nuts 5
The engaging teeth 64 of the 58 and 58 are respectively engaged with the engaging teeth 66 of the mold opening / closing cylinder 12. Thereafter, in this locked state, the second servomotor 48 is rotated forward to rotate the second ball screw shafts 34, 34, thereby forming the mold clamping cylinder 40 and the mold opening / closing cylinder 12 with each other. Are integrally moved forward, and the movable platen 14 is pressed against the fixed platen to perform the mold clamping operation. At this time, since the second ball screw shafts 34, 34 are configured to have smaller leads than the first ball screw shaft 20, the forward driving force due to the rotation of the first ball screw shaft 20 is smaller than the forward driving force. The forward driving force of the large mold clamping cylinder 40 and the mold opening / closing cylinder 12 is obtained, so that the mold clamping operation can be performed at a high pressure.

In general, after the desired injection molding is performed under such a mold-clamped state, when the mold is opened, first, a depressurizing operation is performed. This depressurizing operation is performed by rotating the second servomotor 48 in the reverse direction under the state in which the mold clamping cylinder 40 and the mold opening / closing cylinder 12 are mutually locked by the locking mechanism 56 to move the movable platen 14. This is performed by retreating the mold to the position where the mold closing operation is completed or to the vicinity thereof.

Next, the drive cylinder mechanisms 62, 62 are operated, respectively, to move the pair of half nuts 58, 58 backward, and to detach the half nuts 58, 58 from the mold opening / closing cylinder 12. Then, after that, the first servo motor 24 is rotated in the reverse direction to rotate the first ball screw shaft 20.
Is rotated to move the mold opening / closing cylinder 12 backward, thereby performing the mold opening operation. Also at this time, since the first ball screw shaft 20 is a large lead, as with the forward drive speed of the mold opening / closing cylinder 12, a large retreat driving speed of the mold opening / closing cylinder 12 can be obtained. Thus, the mold opening operation can be performed at a high speed.

When performing predetermined injection molding using an injection molding machine having such a mold clamping device, the mold opening / closing operation, the mold clamping operation, and the pressure of the mold clamping device as described above are performed. The ejection operation is performed in an appropriate order according to the type of the resin material to be injected, the injection molding method employed, and the like.

That is, for example, when performing injection molding using a thermoplastic resin material according to a general injection molding technique, first, as described above, the mold closing operation is performed, and then the mold clamping operation is performed. Do. Next, under the mold clamping state, after injecting the molten resin into the mold cavity from the injection machine, the molten resin in the cavity is cooled and solidified,
A desired molded product is formed. Then, after performing the depressurizing operation as described above, the mold opening operation is performed.

On the other hand, when performing injection molding using a thermosetting resin material by a general injection molding technique, first, as in the case of performing injection molding using a thermoplastic resin material, a mold closing operation is performed. After performing the mold clamping operation, the molten resin is injected from the injection machine into the cavity of the heated mold under the mold clamping state. Thereafter, the molten resin is cured in the cavity of the high-temperature mold. In order to allow the gas generated at that time to leak out of the cavity, a depressurizing operation is performed. Then, after the resin in the cavity is cured and a desired molded product is molded, the mold opening operation is performed.

When injection molding is performed according to a so-called injection compression molding method in which a predetermined compressive force is applied to the molten resin after the molten resin is injected and filled into the cavity of the mold, for example, the following method is used. The mold clamping device is activated in two orders.

That is, as one sequence, first, the mold closing operation is performed as described above. Here, the mold closing operation is stopped immediately before completion. That is, the mold closing operation is stopped in a state in which the mold is not completely closed before the movable mold 14 and the fixed mold come into contact with each other.
At this time, the meshing teeth 64, 64 of the half nuts 58, 58
And the locking teeth 55 of the mold opening / closing cylinder 12 are engaged with each other. Next, in the cavity of such a partially closed mold,
A predetermined molten resin is injected from an injection machine. Thereafter, the second servomotor 48 is driven to rotate to perform a mold closing operation (mold clamping operation) to apply a predetermined compressive force to the molten resin in the cavity. Then, as described above, after the molten resin is solidified or cured to form a desired molded product, the depressurizing operation and the mold opening operation are performed. When the mold clamping device is operated in this order, the forward movement of the mold opening / closing cylinder 12 is stopped immediately before the mold closing operation is completed, and the compression of the molten resin in the cavity is started. Until the injection pressure of the molten resin, an operation control for holding the position of the mold opening / closing cylinder 12 at the stop position is performed on the mold clamping device by a known method. The Rukoto.

In another order, the mold closing operation is completed as described above, and the mold is completely closed. At this time, the meshing teeth 64, 64 of the half nuts 58, 58 and the locking teeth 55 of the mold opening / closing cylinder 12 are mutually engaged. Next, under the condition that the torque of the second servo motor 48 for performing the mold clamping operation is set low,
A predetermined molten resin is injected into the cavity of the mold from an injection machine, and the mold is slightly opened by the injection pressure of the molten resin, so that the mold is in an incompletely closed state. Thereafter, the second servomotor 48 is driven to rotate to perform a mold closing operation (mold clamping operation). Thereby, a predetermined compressive force is applied to the molten resin in the cavity. Then, in the same manner as described above, the molten resin is solidified or cured to form a desired molded product, and then the depressurizing operation and the mold opening operation are performed.

By the way, when a general injection molding method is carried out using a mold clamping device having such a configuration,
Once the mold is closed, the molten resin is injected into the cavity of the mold, and the mold is slightly opened with the injection pressure of the molten resin.
When performing the injection compression molding method in which the mold closing operation (mold clamping operation) is performed, the half nuts 58, 58 are placed at the mold closing position of the mold opening / closing cylinder 12 before the molten resin is injected. It is necessary to engage the mold opening / closing cylinder 12 with the engaging teeth 6 of the half nut 58.
If the locking teeth 66 of the mold 4 and the mold opening / closing cylinder 12 are not at corresponding positions, they cannot be locked well. Therefore, at the mold closing position of the mold opening / closing cylinder 12, the half nut 5
In order to ensure that the cylinders 8, 58 are always locked to the mold opening / closing cylinder 12, an operation control method for adjusting the locking position using the second servomotor 48, for example, as described below is preferable. Will be adopted.

First, the first servomotor 2 is formed using a mold block (model mold) having a reference minimum mold thickness whose mold thickness is smaller than at least the mold to be mounted.
4) Absolute position detection (origin search) and mold opening / closing cylinder 12
Of the mold opening / closing cylinder 12 and the mold clamping cylinder 40 in a state where the meshing teeth 64 of the half nut 58 attached to the nut and the locking teeth 66 of the mold opening / closing cylinder 12 are mutually engaged. Of origin. Specifically, for example, (1) the mold opening / closing cylinder 12 is manually or finely moved (jog) while the mold block is mounted on the fixed platen and the movable platen 14, respectively. Operation), the model dies mounted on the fixed platen and the movable platen 14 are brought into contact with each other, thereby bringing the mold closed state, and the mold opening / closing cylinder 12 when the mold closing is completed. Is set as the mold position reference origin while the mold opening / closing cylinder 12 is
Is set as the origin (0.00 mm) as the rotation position of the first servomotor 24 positioned at the mold position reference origin, and stored. (2) On the other hand, the mechanical limit of the movable range of the mold clamping cylinder 40 driven by the second servomotor 48 is actually measured, and the measured value (Amm) is used for the mold clamping cylinder 40. The position of the mechanical limit in the die depressing direction, in other words, is set as a mold clamping cylinder position reference point indicating the retreat end position of the mold clamping cylinder 40 and stored.
(3) The mold opening / closing cylinder 12 is set to the mold closing completion position (mold position reference origin) where the rotation position of the first servomotor 24 is the origin, and the mold clamping cylinder 40 is at the retreat end position. The engagement teeth 64 of the half nut 58 and the mold opening and closing cylinder 1
The axial position of the clamping cylinder 40 is mechanically finely adjusted without driving the second servomotor 48 so that the two locking teeth 66 can be locked to each other at corresponding positions. It is done by adjusting.

Subsequently, at the mold closing position of the mold having the desired thickness to be actually mounted, the meshing teeth 64 of the half nut 58 are set.
The control position (movement amount) of the mold clamping cylinder 40 by the second servomotor 48 at which the locking teeth 66 of the mold opening / closing cylinder 12 can be mutually locked is stored as described above. This is obtained based on the respective position data of the mold position reference origin of the mold opening / closing cylinder 12 and the mold clamping cylinder position reference point of the mold clamping cylinder 40. This is performed, for example, by a flowchart shown in FIG. It will be performed according to.

That is, first, in step 1 (hereinafter, S1
Is abbreviated. Same for other steps)
A target range D of the axial movement amount of the mold clamping cylinder 40 is calculated according to the following (Equation 1) and (Equation 2). In this case, the mold clamping cylinder 40 can be mechanically moved to the retracted end position (Amm) with respect to the mold opening / closing cylinder 12, but for actual locking operation, Since it is sufficient to move the meshing teeth 64 (locking teeth 66) relative to each other by the axial pitch (Bmm), this range is set as the target range of the axial movement amount of the mold clamping cylinder 40: D. Is

F = E + B (Equation 1) E <D ≦ F (Equation 2) where E is the lower limit value of D, and the extension of the guide rod 16 at the time of increasing the mold clamping pressure. This value takes into account minutes. F is D
And is obtained according to the above (Equation 1) on condition that F <A.

Next, in S2, the absolute position: H of the mold opening / closing cylinder 12 when the mold closing is completed is calculated. The absolute position H indicates an axial position of the mold opening / closing cylinder 12 with respect to the mold position reference origin when the mold to be actually mounted is closed. Is obtained by subtracting the dimension of the reference minimum mold thickness (mold thickness dimension of the mold block): C from the mold thickness dimension of G: G.

Then, in S3, the remainder: J of the value obtained by dividing the absolute position: H calculated in S2 by the pitch: B of the meshing teeth 64 (locking teeth 66) is calculated. The remainder: J is the meshing tooth 64 of the half nut 58 and the mold opening / closing cylinder 12 obtained by considering only the absolute position H of the mold opening / closing cylinder 12 with respect to the mold position reference origin when the mold closing is completed. This is the control position (movement amount) of the mold clamping cylinder 40 for interlocking the locking teeth 66 with each other.

Next, in S4, the mold clamping cylinder 40
The mold clamping cylinder position reference point indicating the retracted end position of
Mechanical limit of the movable range of the mold clamping cylinder 40: A value obtained by subtracting the pitch B of the meshing teeth 64 (locking teeth 66) from A:
K is calculated, and it is determined whether or not this subtraction value: K is 0 or less. Then, when it is determined that the subtraction value: K is larger than 0, S4 is executed again. On the other hand, when it is determined that the subtraction value: K is 0 or less,
S5 and subsequent steps are executed. Note that the subtraction value: K obtained here is a meshing tooth 64 of the half nut 58, which is obtained by considering only the reference position of the mold clamping cylinder 40 of the mold clamping cylinder 40.
This is the control position (movement amount) of the mold clamping cylinder 40 for interlocking the locking teeth 66 of the mold opening / closing cylinder 12 with each other.

Subsequently, in S5, a value obtained by adding the remainder: J obtained in S3 and the subtraction value: K obtained in S4: L
Is calculated. The added value: L is the absolute position of the mold opening / closing cylinder 12 with respect to the mold position reference origin when the mold closing is completed: H
The engagement teeth 64 of the half nut 58 and the locking teeth 66 of the mold opening / closing cylinder 12 are mutually locked, which are determined in consideration of both the mold clamping cylinder body 40 and the mold clamping cylinder body position reference point. This is a target value of the control position (movement amount) of the mold clamping cylinder 40 that can be performed.

Next, in S6, it is determined whether or not the target value (added value) L obtained in S5 is larger than the lower limit value E of the target range D. When it is determined that the target value: L is equal to or smaller than the lower limit value: E, in S7, the meshing teeth 64 (the locking teeth 6
6) The pitch: B is further added to obtain the added value: L, and then S6 is executed again. Note that S6 and S6
The repetition of 7 is executed until the condition of E <L ≦ F is satisfied. On the other hand, if it is determined that the target value: L is larger than the lower limit value: E, S8 and the subsequent steps are executed.

Thereafter, in step S8, the target value: L is set to the second servomotor 4 in which the meshing teeth 64 of the half nut 58 and the locking teeth 66 of the mold opening / closing cylinder 12 can be locked to each other.
The control position (movement amount) of the mold clamping cylinder 40 according to 8 is stored as X.

In order to clarify such an operation, a calculation example of a mold clamping device having a set value as shown in the following Table 1 will be described below as one specific example.

[0053]

F = E + B = 6.00 + 12.00 = 18.00 (mm) H = GC = 234.56−200.00 = 34.56
(Mm) H / B = 34.56 / 12.00 = the remainder 10.56 ∴J = 10.56 (mm) K = AB = 20−12 = 8.00 Since 0 <K, K = 8 .00-12.00 = -4.00 (mm) L = J + K = 10.56--4 = 6.56 (mm) Because E <L, X = L = 6.56 (mm)

Accordingly, by driving the second servo motor 48, the mold clamping cylinder 40 is moved to the retreating side by X = 6.56 mm from the reference origin on the forward end side, thereby being movable. Board 14 (Cylinder 12 for opening and closing the mold)
In the mold closing position, the meshing teeth 64 of the half nut 58 are
The locking teeth 66 of the mold opening / closing cylinder 12 can be set so as to take positions where they can be locked to each other.

On the other hand, using such a mold clamping device, after injecting the molten resin into the cavity of the imperfectly closed mold immediately before the completion of the mold closing operation, an injection compression in which the mold closing operation (mold clamping operation) is performed. When the molding method is performed, as described above, the mold closing operation (mold closing operation) after the injection of the molten resin is performed while the half nuts 58 and 58 are locked to the mold opening / closing cylinder 12. This is performed by integrally moving the mold clamping cylinder 40 and the mold opening / closing cylinder 12 with the rotation of the second servomotor 48. Therefore, in such a case, it is necessary to lock the half nuts 58, 58 to the mold opening / closing cylinder 12 immediately before the mold closing of the mold opening / closing cylinder 12 is completed. Immediately before the closing of the mold cylinder 12, the meshing teeth 64 of the half nut 58 and the locking teeth 66 of the mold opening and closing cylinder 12 must be positioned so as to correspond to each other.

Therefore, using the mold clamping device of this embodiment,
When performing the injection compression molding method as described above, the second servomotor 48 described above is used while taking into account the amount of movement of the mold opening / closing cylinder 12 from the position immediately before the mold closing completion position to the mold closing completion position. An operation control relating to the adjustment of the used locking position is performed (for example, such an amount of movement is added to the actual thickness of the mold to be mounted, and the added value is defined as the mold thickness dimension: G, and the mold clamping cylinder is used. By determining the control position of the body 40), the meshing teeth 64 of the half nut 58 and the locking teeth 66 of the mold opening / closing cylinder 12 correspond to each other immediately before the mold closing of the mold opening / closing cylinder 12 is completed. Then, the positioning of the mold clamping cylinder 40 is performed.

As described above, in the present embodiment, the first servo motor 24 drives the first ball screw nut 32 screwed to the first ball screw shaft 20 having a large lead to feed the screw. The opening and closing operation of the mold is performed at a high speed based on the second ball screw shaft 3 having a small lead by the driving of the second servomotor 48.
Second ball screw nuts 36, 3 screwed into
Based on the screw feeding action of No. 6, the mold clamping / releasing operation is performed, and in particular, the mold clamping operation is performed at a high pressure.

Therefore, according to this embodiment, it is possible to effectively shorten the molding cycle by opening and closing the mold at a high speed, and to effectively secure excellent molding accuracy by high-pressure pressing of the mold. It becomes.

In the present embodiment, the half nut 5 which can be reciprocated in the direction of approach / separation with respect to the mold opening / closing cylinder 12 is provided at the tip of the mold clamping cylinder 40.
While a locking mechanism 56 having 8, 58 is mounted,
Locking teeth 66, which can be locked to the meshing teeth 64, 64 provided on the half nuts 58, 58 of the locking mechanism 56, respectively, engage with the meshing teeth 64 with respect to the outer peripheral surface of the mold opening / closing cylinder 12. With a sawtooth-shaped cross section of a cross-sectional shape corresponding to
A large number of strips are formed at equal intervals in the axial direction so as to extend continuously in the circumferential direction, and the second servo is driven by the engagement between the engagement teeth 64 and the engagement teeth 66. By driving the motor 48 and moving the mold clamping cylinder 40 and the mold opening / closing cylinder 12 forward integrally, the mold clamping operation is performed.
The mold opening / closing cylinder 12 and the mold clamping cylinder 40 are securely engaged with a large locking strength over a wide range of the axial relative position of the mold opening / closing cylinder 12 with respect to the mold clamping cylinder 40. It is possible to effectively widen the range of mold thickness of the mold that can be mounted, and to lock and release the mold opening / closing cylinder 12 and the mold clamping cylinder 40. Can be performed quickly. As a result, the mold clamping operation can be performed more smoothly.

Further, in the present embodiment, by controlling the moving position of the mold clamping cylinder 40 using the second servomotor 48, the meshing teeth of the half nut 58 are set at the mold closing position of the movable platen 14. 64 and the locking teeth 66 of the mold opening / closing cylinder 12 can be set so as to take a relative position where they can be locked to each other. When the mold closing operation is completed, the mold closing cylinder 40 and the mold opening / closing cylinder 12
Can be mutually locked, so that the molding cycle can be further shortened and the like can be achieved even more advantageously.

Further, in the present embodiment, based on the screw feed action of the second ball screw nuts 36, 36 screwed to the second ball screw shafts 34, 34, the die pressing / releasing operation is performed. Is performed, compared to a conventional device in which such an operation is performed using a hydraulic mechanism,
The amount of actuation of the pressing / depressurizing operations of these dies can be controlled quickly and accurately, so that when general injection molding is performed using a thermosetting resin material, the amount generated when the molten resin is cured. The degassing operation of the gas from the cavity can be smoothly and reliably performed by performing the depressurizing operation of the mold. In addition, when performing the injection compression molding, the pressurizing operation on the molten resin in the cavity is performed. However, by performing the pressing operation of the mold, the operation can be smoothly and reliably performed.

Although the embodiment of the present invention has been described in detail, it is merely an example, and the present invention is not construed as being limited to such an embodiment. Should be understood.

For example, in the above-described embodiment, the second ball screw shaft 34 into which the second ball screw nut 36 for performing the forward / backward movement of the mold clamping cylinder 40 is fitted is the mold opening / closing cylinder body. The first ball screw shaft 2 into which the first ball screw nut 32 for performing the forward / backward movement of the shaft 12 is screwed.
The two ball screw shafts 34 are arranged one by one on both sides of the first ball screw shaft 20, and rotate around the center axis while extending in parallel with the center axis of the first ball screw shaft 20. As long as it is supported as possible and immovable in the direction of the central axis, the arrangement position and the number of the arrangement are not limited to this.

In the above embodiment, the first ball screw shaft 20 is constituted by a large lead,
The driving speed of the forward / backward movement of the mold clamping cylinder 40 is increased to achieve high-speed opening and closing of the mold. On the other hand, the second ball screw shaft 34 is configured with a small lead, so that the mold clamping cylinder is formed. The forward / reverse driving force of the fork 40 is increased to realize high-pressure clamping of the mold. However, the first ball screw shaft 20 and the second ball screw shaft 34 are connected to each other except for the size of the lead. It is, of course, possible to realize both high-speed opening and closing of the mold and high-pressure pressing by making the structures different from each other.

Further, in the above-described embodiment, the mold opening / closing cylinder and the mold clamping member are constituted by the mold opening / closing cylinder 12 and the mold clamping cylinder 40 having a cylindrical shape, respectively. However, the shape of those members is not particularly limited to this, and the mold opening / closing tubular body has a tubular shape that can be externally arranged on the first ball screw shaft, and cannot rotate around the central axis. And if it is movable in the direction of the central axis,
The mold-clamping member has any shape as long as the mold-clamping member can be locked to the mold-opening / closing tubular body and is provided so as to be movable in the center axis direction of the mold-opening / closing tubular body. However, there is no problem.

Further, it goes without saying that the structure of the locking means is not limited to the one shown in the above embodiment.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, various changes, modifications, improvements, and the like can be made, and any of such embodiments can be implemented in the present invention without departing from the spirit of the present invention. It is to be understood that they are included within the scope of the invention.

[0069]

As is apparent from the above description, in the mold clamping device in the injection molding machine according to the present invention, a simple and compact ball screw mechanism is used to open and close the mold at high speed and to perform high-pressure clamping. Can be realized at the same time, and as a result, the molding cycle can be effectively shortened, and the improvement of the molding accuracy can be extremely effectively achieved.

Further, according to the method of controlling the operation of the mold clamping device in the injection molding machine according to the present invention, regardless of the thickness of the mold, immediately and surely upon completion of the mold closing operation.
The mold clamping member and the mold opening / closing tubular body can be mutually locked by the locking means, so that the molding cycle can be further shortened and the like can be achieved even more advantageously. It becomes.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an example of an injection device according to the present invention, and shows a sectional view taken along the line II in FIG.

FIG. 2 is an explanatory sectional view taken along the line II-II in FIG.

FIG. 3 is an explanatory sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a flowchart for explaining operation control relating to adjustment of a locking position between a mold clamping cylinder and a mold opening / closing cylinder according to the method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Base 12 Cylindrical body for opening and closing a mold 14 Movable platen 20 First ball screw shaft 24 First servo motor 32 First ball screw nut 34 Second ball screw shaft 36 Second ball screw nut 40 Mold clamping cylinder Body 48 Second servo motor 56 Locking mechanism 58 Half nut 62 Drive cylinder mechanism 64 Mesh teeth 66 Locking teeth

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AR07 CA11 CB01 CL09 CL22 CL39 CL48 4F206 AR077 JA07 JM02 JM06 JN33 JQ81 JQ83 JT05 JT33 JT38

Claims (3)

[Claims] 1. A first ball screw shaft fixed in position rotatable around a central axis, first driving means for driving the first ball screw shaft to rotate, and an outer member connected to the first ball screw shaft. A mold opening / closing tubular body which is inserted and arranged, and which has a movable plate attached to an axial end thereof, is not rotatable around a central axis and is movable in the central axis direction, and the first ball screw shaft. Screwed and fixed to the mold opening / closing tubular body to move the mold opening / closing tubular body in the direction of its central axis with rotation of the first ball screw shaft. One ball screw nut, and a second ball screw shaft provided so as to be rotatable about the central axis and immovable in the central axis direction in a state extending in parallel with the central axis of the first ball screw axis. Second driving means for rotating and driving the second ball screw shaft; A mold-clamping member movably provided in the central axis direction of the cylinder for opening and closing the mold and capable of being locked to the cylinder for opening and closing the mold, and screwing with the second ball screw shaft; And by being fixed to the mold-clamping member, the mold-clamping member is moved in the center axis direction of the mold opening / closing tubular body with the rotation of the second ball screw shaft. A second ball screw nut, provided between the mold-clamping member and the mold-opening / closing tubular body, interlocking the mold-clamping member and the mold-opening / closing tubular body, An injection molding machine, comprising: locking means for allowing the movement of the mold-clamping member to be exerted as a mold-clamping force by the mold-opening / closing tubular body by allowing them to move integrally. Mold clamping device. 2. The method according to claim 1, wherein the locking means includes a plurality of locking teeth formed at regular intervals in an axial direction on an outer peripheral surface of the mold opening / closing cylindrical body and extending in a circumferential direction, and a plurality of locking teeth. On the other hand, it is supported so as not to be able to move in the axial direction, and is displaced in the direction of approaching / separating from the outer peripheral surface of the cylindrical body for opening and closing the mold. The mold clamping device in an injection molding machine according to claim 1, further comprising: a locking block having a meshing tooth to be locked / removed. 3. The mold clamping device of the injection molding machine according to claim 2, wherein when performing the mold clamping operation, a model mold having a reference minimum mold thickness smaller than at least the mold to be mounted is mounted. The axial position of the mold opening / closing tubular body at the mold closing completion position under the condition is defined as a mold position reference origin, and the engaging teeth are engaged with the locking teeth of the mold opening / closing tubular body at the mold closing completion position. The axial position of the mold clamping member in the center axis direction of the mold opening / closing tubular body is adjusted so that the engagement teeth of the stop block can be locked, and the mold clamping member position reference points are used. Based on the reference origin and the position data of the mold clamping member position reference point, the locking teeth formed on the mold opening / closing tubular body at the mold closing completion position when a mold having an arbitrary mold thickness is mounted. So that the meshing teeth of the meshing block can be locked to the center of the mold opening / closing tubular body. Operation control method for a mold clamping device in an injection molding machine, characterized by adjusting the axial position of the mold clamping member in the direction.