JPH09207181A - Mold clamping apparatus for precise injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the dynamic precision of a fixed die plate by making the flexural deformation of the die plate which is generated in mold clamping minute and uniform. SOLUTION: A fixed die plate 23 and a mold clamping cylinder 27 are connected with each other by a tie-bar 29, and the cylinder 27 is fixed on a base 21. By the actuation of the cylinder 27, the mold clamping is done between the fixed mold 31 of the fixed die plate 23 and the movable mold 33 of a movable die plate 25. A slip plate 43 of a sintered material impregnated with oil is attached to the supporting foot 23a of the fixed die plate 23, and the slip plate 43 makes the slight movement of the fixed die plate 23 smooth when the plate 23 is bent by being pulled by the tie-bar 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention clamps a mold to each other in a state where a movable mold held by a movable die plate is in close contact with a fixed mold held by a fixed die plate. The present invention relates to a mold clamping device for a precision injection molding machine.

[0002]

2. Description of the Related Art FIG. 11 is a front view showing an outline of a mold clamping device in an injection molding machine, in which a fixed die plate 5 holding a fixed mold 3 is mounted on a base 1 which serves as a molding machine main body frame. A movable die plate 7 is provided on the base 1 so as to be slidable with respect to the base 1 and to be movable in a direction of approaching and separating from the fixed die plate 5. On the surface of the movable die plate 7 that faces the fixed die plate 5, a movable die 11 that holds the fixed die 3 and forms a cavity space for a molded product is held.

A mold clamping cylinder 13 is fixed via a supporting plate portion 13a on the base 1 opposite to the fixed die plate 5 with the movable die plate 7 interposed therebetween. In the mold clamping cylinder 13, the tip of the mold clamping ram 15 is fixed to the moving die plate 7, and the mold clamping ram 15 moves forward and backward by the operation of the mold clamping cylinder 13 to move the movable die plate 7.
Moves toward and away from the fixed die plate 5. The support plate portion 13a and the fixed die plate 5 are connected and fixed to each other by a tie bar 19, and the movable die plate 7
Is guided by the diver 19 and moves.

FIG. 11 shows a state in which the movable die plate 7 approaches the fixed die plate 5 to perform mold clamping. At the time of this mold clamping, the fixed die plate 5 and the support plate portion 13a are connected. The tie bar 19 that supports the mold clamping reaction force stretches and deforms, and the fixed die plate 5 and the mold clamping cylinder 13 are pulled together through the tie bar 19, and as a result, for example, the fixed die plate 5 side For example, it undergoes bending deformation as shown by the chain double-dashed line. At this time, the fixed die plate 5 slightly slides in the direction of arrow A with respect to the base 1 so as to absorb the above bending deformation.

[0005]

By the way, in a mold clamping apparatus for molding a general molded product, the above-mentioned bending deformation of the fixed die plate, which occurs during mold clamping, has little influence on the molded product. Therefore, the so-called dynamic accuracy of the fixed die plate due to such bending deformation is not particularly a problem.Therefore, when designing the fixed die plate, it is necessary to perform machining or assembly at the component stage. Considers static accuracy as the main subject. On the other hand, when molding high precision precision molded products that require precision of several microns, such as optical components and ultra-thin magneto-optical disks, ignore the above-mentioned dynamic accuracy due to bending deformation. Therefore, it is necessary to stabilize the dynamic accuracy by making the bending deformation minute and uniform.

However, in the conventional mold clamping device shown in FIG. 11, the fixed die plate is slidable with respect to the base at the time of bending deformation, but its sliding resistance is relatively large, and the deformation operation of the lower part is difficult. It was not as smooth as the upper side, which was free, and the fixed die plate was not evenly bent and deformed in the vertical direction, resulting in unstable dynamic accuracy and insufficient molding accuracy for precision molded products. .

In view of this, the present invention aims to stabilize the dynamic accuracy of the fixed die plate or the mold clamping drive means by making the bending deformation of the fixed die plate or the mold clamping drive means that occurs during mold clamping minute and uniform. Has an aim.

[0008]

In order to achieve the above object, the present invention is, firstly, to provide a fixed die plate for holding a fixed die and a movable die, and to approach the fixed die plate. A movable die plate movable in a separating direction, a mold clamping drive means for clamping the movable die plate by pressing the movable die plate against the fixed die plate side, and connecting the mold clamping drive means and the fixed die plate to each other. In a mold clamping device of a precision injection molding machine including a tie bar that receives a mold clamping reaction force at the time of clamping, a lower end surface of one of the fixed die plate and the mold clamping drive means and a molding machine body frame. A guide portion is provided between the fixed die plate and the mold clamping drive means for reducing sliding resistance when the fixed mold plate or the mold clamping drive means slides on the molding machine body frame due to its deformation.

Secondly, in the first structure, the guide portion is
It is a sliding plate made of a sintered material impregnated with oil.

Thirdly, in the first structure, the guide portion is
It is a linear guide mechanism.

Fourth, a fixed die plate for holding the fixed die, and a movable die plate for holding the movable die and movable in a direction of approaching and separating from the fixed die plate,
A mold clamping drive means for pressing the movable die plate against the fixed die plate side to perform mold clamping, and a tie bar that connects the mold clamping drive means and the fixed die plate and receives a mold clamping reaction force during mold clamping. In a mold clamping device of a precision injection molding machine equipped with, one of the fixed die plate and the mold clamping drive means has a sliding surface that slides on the molding machine body frame due to its deformation during mold clamping. A notch is provided at a corner of the sliding surface opposite to the moving die plate.

Fifth, in the fourth structure, the notch is formed by chamfering.

Sixth, in the fourth structure, the notch is formed by a step.

Seventh, in the sixth configuration, an elastic body is interposed between the step portion and the molding machine body frame.

Eighth, a fixed die plate for holding the fixed die, and a movable die plate for holding the movable die and movable in a direction of approaching and separating from the fixed die plate,
A mold clamping drive means for pressing the movable die plate against the fixed die plate side to perform mold clamping, and a tie bar that connects the mold clamping drive means and the fixed die plate and receives a mold clamping reaction force during mold clamping. In a mold clamping device of a precision injection molding machine equipped with, one of the fixed die plate and the mold clamping driving means is a main body part separated from the main frame of the molding machine, and is separated from the main body part. A support bracket portion formed on the body and having a bottom surface that slides on the molding machine main body frame, the lower portion of the main body portion being in a direction orthogonal to the tie bar and the upper surface of the molding machine main body frame. It is rotatably supported via a support shaft extending in a direction parallel to.

According to the mold clamping device of the precision injection molding machine having such a configuration, the movable die plate is pressed against the fixed die plate side by the operation of the mold clamping drive means, and the mold clamping is performed. The force is received by the tie bar and the fixed die plate and the mold clamping drive means are mutually pulled.One of the fixed die plate and the mold clamping drive means has a lower end surface with respect to the molding machine main body frame through a guide part. Since they undergo bending deformation while sliding in directions away from each other with little sliding resistance, the bending deformation is almost the same as the free upper side, and either the fixed die plate or the mold clamping drive means can be used. On the other hand, the deformation becomes minute and uniform with vertical symmetry, the dynamic accuracy is stable, and it can be applied to a precision injection molding machine that requires high accuracy.

Further, even if one of the fixed die plate and the mold clamping drive means is bent and deformed so that the upper and lower ends are pulled toward the moving plate side by the tie bars during the mold clamping, the fixed die plate or the mold clamping drive means is deformed. By providing the notch at the corner of the sliding surface opposite to the moving die plate, the force for pressing the molding machine body frame at the end of the sliding surface opposite to the moving die plate is reduced. The deformation of the lower side that contacts the molding machine body frame is almost the same as the free upper side,
Either one of the fixed die plate and the mold clamping drive means has a small deformation and is vertically symmetrical and uniform, the dynamic accuracy is stable, and it can be applied to a precision injection molding machine that requires high accuracy. .

Further, a support is provided in which a main body part of one of the fixed die plate and the mold clamping drive means is provided on the molding machine main body frame via a support shaft in a state of being separated from the molding machine main body frame. By making it rotatable with respect to the bracket portion, even if the upper and lower ends of the fixed die plate or the mold clamping drive means are deformed so as to be pulled to the moving plate side by the tie bars during mold clamping, the lower side is still supported by the support shaft. Since it rotates, the bending deformation is smooth, and the deformation is almost the same as the free upper side, and either one of the fixed die plate and the mold clamping drive means has a small deformation and is vertically symmetrical and uniform. Dynamic accuracy is stable,
It can be applied to precision injection molding machines that require high precision.

[0019]

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

1 to 4 show a mold clamping device of a precision injection molding machine according to an embodiment of the present invention. FIG. 1 is a front view, FIG. 2 is a plan view of FIG. 1, and FIG. Right side view of FIG. 1,
FIG. 4 is a left side view of FIG.

In this mold clamping device, a fixed die plate 23, a movable die plate 25, and a mold clamping cylinder 27 composed of a hydraulic cylinder as a mold clamping driving means are provided on a base 21 which serves as a molding machine main body frame. It is provided.
The fixed die plate 23 and the mold clamping cylinder 27 are connected and fixed by four tie bars 29 provided at the four corners,
A fixed die 31 and a movable die 33 are held on the die plates 23 and 25 in a state of facing each other. In the mold clamping cylinder 27, a mold clamping ram 37 is housed in a cylinder body 35 so as to be movable in the left-right direction in FIG. 1, and the tip of the mold clamping ram 37 is fixed to the moving die plate 25. The four tie bars 29 penetrate the movable die plate 25, and the movable die plate 25 is guided by the diver 29 when moving toward and away from the fixed die plate 23.

The mold clamping cylinder 27 is composed of the cylinder body 3
5 has a support plate portion 35a, and as shown in FIG.
Support legs 35b formed at the lower ends of both ends of the support plate portion 35a in the width direction (left and right direction in FIG. 4) are fixed on the base 21 by bolts 39. Support plate portion 35a
A cylinder main body 41a of the mold opening / closing cylinder 41 is attached to the central portion in the vertical direction on both sides in the width direction. A rod 41b housed so as to be movable in the left-right direction in FIG. 1 from the cylinder body 41a has its tip mounted on both sides in the width direction of the movable die plate 25 (direction orthogonal to the paper surface in FIG. 1). Installed on. That is, the movement of the two mold opening / closing cylinders 41 causes the movable die plate 25 to move in the direction in which the movable die plate 25 moves toward and away from the fixed die plate 23.

The fixed die plate 23 is used for the mold clamping cylinder 2.
Similar to the support plate portion 35a of FIG. 7, as shown in FIG.
a is formed, and a slide plate 43 as a guide is attached to the lower end surface 23b of the support leg 23a. Sliding plate 43
Is made of a sintered material impregnated with oil and is slidable with respect to the base 21.

Support legs 23a of the fixed die plate 23
On both sides of the recessed portion 23, a recess 23 extending in the left-right direction in FIG.
c is formed. On the other hand, on the base 21 on the side of the recess 23c, a holding bracket 45 is fixed by a bolt 47, and a projection 45a formed on the holding bracket 45 enters the recess 23c.

Next, the operation of the mold clamping device of the precision injection molding machine as described above will be described.

First, by the operation of the mold opening / closing cylinder 41,
The movable die plate 25 moves toward the fixed die plate 23 together with the mold clamping ram 37, and the movable die 33 comes into close contact with the fixed die 31. By operating the mold clamping cylinder 27 in this state, the movable die plate 25 is pressed against the fixed die plate 23 side, a mold clamping force is applied between the respective dies 31 and 33, and the mold clamping operation is completed.

The reaction force of the mold clamping force generated during the mold clamping operation is supported by the four tie bars 29, and the fixed die plate 23 is expanded and deformed as the tie bars 29 deform.
And the mold clamping cylinder 27 are mutually pulled, and at this time, the fixed die plate 23 has its upper and lower ends moved by the movable die plate 25 as shown by the two-dot chain line in FIG.
It bends and deforms while moving slightly away from.

At the time of this deformation, the lower side of the fixed die plate 23 is deformed and moved in the direction away from the movable die plate 25 with a very small sliding resistance by the action of the sliding plate 43 attached to the support leg 23a. As a result, the deformation on the lower side of the fixed die plate 23 becomes almost equal to that on the upper side which has become free, and the expansion deformation of the tie bar 29 also becomes smooth and the load applied to the fixed die plate 23 is made uniform. The deformation of the plate 23 is minute and uniform in the vertical symmetry, and the dynamic accuracy of the fixed die plate 23 is stable, and it can be applied to a precision injection molding machine that requires high accuracy.

5 and 6 are modifications of the embodiment shown in FIGS. 1 to 4. In this embodiment,
A pair of support legs 49a is formed at the lower ends of both ends of the fixed die plate 49 in the width direction (left and right direction in FIG. 6), and a linear guide as a guide portion is provided between the lower end surface 49b of each of the support legs 49a and the base 21. The mechanism 51 is interposed. The linear guide mechanism 51 includes a guide rail 53 extending on the base 21 in the moving direction of the moving die plate 25,
Each of the guide rails 53 is fitted with a linear bearing 55 mounted on the lower end surface 49b of the support leg 49a of the fixed die plate 49. A roller (not shown) is provided on the side of the linear bearing 55, and this roller rotates and moves on the guide rail 53 when the fixed die plate 49 deforms and moves during mold clamping.

Also in the embodiment shown in FIGS. 5 and 6, the movable die plate 2 of the fixed die plate 49 at the time of mold clamping is used.
Since the linear guide mechanism 51 smoothes the slight deformation movement in the direction away from 5, with the linear guide mechanism 51 having a very small sliding resistance, the bending deformation on the lower side of the fixed die plate 49 becomes free. Is almost the same as
The deformation of the fixed die plate 49 is minute and vertically symmetrical and uniform, and can be applied to a precision injection molding machine that requires high precision.

The sliding plate 43 shown in FIGS.
And, the linear guide mechanism 51 in FIGS.
Although a pair is provided on both side portions in the width direction, it may be provided one at the center portion in the width direction.

FIG. 7 is an enlarged schematic view of the lower periphery of a fixed die plate according to another embodiment of the present invention. The fixed die plate 57 here has a sliding surface 57a that slides on the base 21 due to its bending deformation during mold clamping, and the moving die plate of this sliding surface 57a located to the left in FIG. A chamfered portion 57b as a cutout portion is formed at a corner opposite to the corner.

The chamfered portion 57b is shown in FIG.
As described above, when the fixed die plate 57 is bent and deformed, the pressing force against the base 21 does not act as much as possible. With such a shape, the bending deformation operation on the lower side of the fixed die plate 57 can be performed by the chamfered portion 5.
Since 7b is provided, the pressing force of the fixed die plate 57 against the base 21 is small, and the bending deformation of the lower side is smooth as in the free upper side. Smoothing, the load applied to the fixed die plate 57 becomes uniform,
As a result, the deformation of the fixed die plate 57 becomes minute and vertically symmetrical and uniform, and it can be applied to a precision injection molding machine that requires high precision.

FIG. 8 shows that the chamfered portion 5 of FIG. 7 is formed at the corner of the sliding surface 59a at the lower end of the fixed die plate 59 opposite to the moving die plate located leftward in FIG.
The stepped portion 59b instead of 7b is formed as a cutout portion. Also in this case, by forming the step portion 59b, the bending deformation operation of the lower end of the fixed die plate 59 is facilitated, and the same effect as the example of FIG. 7 is obtained. Further, in this example, an oil film is formed in the step portion 59b, and the oil film facilitates sliding of the fixed die plate 59 with respect to the base 21.

FIG. 9 shows a modification of FIG. 8 in which an elastic body 61 is housed in a recess 59c formed in the step 59b. The elastic body 61 is composed of a spring 61a and a steel ball 61b. In this example, the action of the oil film in FIG. 8 is performed by the elastic body 61.

In FIG. 10, the fixed die plate 63 is separated from the main body portion 65, and the bottom surface 67 a formed separately from the main body portion 65 slides on the base 21. It is composed of a support bracket portion 67. The main body portion 65 has a support shaft 69 extending from the support bracket portion 67 in a direction orthogonal to the tie bars (extended in the left-right direction in FIG. 10) and in a direction parallel to the upper surface of the base 21. It is rotatably supported via.

With such a structure, at the time of mold clamping, the fixed die plate 63 causes the support bracket portion 67 to slide with respect to the base 21, and at the same time, the lower side of the main body portion 65 rotates about the support shaft 69. As a result, the bending deformation operation is smoothly performed.

In each of the above embodiments, the present invention is applied to the fixed die plate side as a structure for slidingly supporting the fixed die plate 23, 49, 57, 59, 63 side with respect to the base 21. The mold clamping cylinder 27 side is the base 2
The present invention may be applied to the mold clamping cylinder side as a structure in which it is slidably supported with respect to 1.

[0039]

As described above, according to the present invention, the movable die plate is pressed against the fixed die plate side by the operation of the die clamping drive means to perform die clamping.
The mold clamping reaction force is received by the tie bar and the fixed die plate and the mold clamping drive means are mutually pulled, and one of the fixed die plate and the mold clamping drive means has a lower end surface with respect to the molding machine body frame. Since it slides with a small sliding resistance via the guide part, its bending deformation is almost the same as the free upper side, and either one of the fixed die plate and the mold clamping drive means is not deformed. It becomes minute and vertically symmetrical and uniform, the dynamic accuracy is stable, and it can be applied to precision injection molding machines that require high accuracy.

Even if one of the fixed die plate and the mold clamping driving means is bent and deformed so that the upper and lower ends are pulled toward the moving plate side by the tie bars during mold clamping, the fixed die plate or the mold clamping driving means may be deformed. By providing the notch at the corner of the sliding surface opposite to the moving die plate, the force for pressing the molding machine body frame at the end of the sliding surface opposite to the moving die plate is reduced. The deformation of the lower side that contacts the molding machine body frame is almost the same as the free upper side,
Either one of the fixed die plate and the mold clamping drive means has a small deformation and is vertically symmetrical and uniform, the dynamic accuracy is stable, and it can be applied to a precision injection molding machine that requires high accuracy. .

Further, the main body of the molding machine main body frame, in which one of the fixed die plate and the mold clamping drive means is separated from the molding machine main body frame, is supported via the support shaft on the molding machine main body frame. By making it rotatable with respect to the bracket portion, even if the upper and lower ends of the fixed die plate or the mold clamping drive means are deformed so as to be pulled to the moving plate side by the tie bars during mold clamping, the lower side is still supported by the support shaft. Since it rotates, the bending deformation is smooth, and the deformation is almost the same as the free upper side, and either one of the fixed die plate and the mold clamping drive means has a small deformation and is vertically symmetrical and uniform. Dynamic accuracy is stable,
It can be applied to precision injection molding machines that require high precision.

[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 plan view of FIG.

FIG. 3 is a right side view of FIG. 1;

FIG. 4 is a left side view of FIG. 1;

5 is a front view showing a modified example of the mold clamping device of the precision injection molding machine of FIG. 1. FIG.

FIG. 6 is a right side view of FIG.

FIG. 7 is an enlarged schematic view of a lower portion of a fixed die plate according to another embodiment of the present invention.

FIG. 8 is an enlarged schematic view of the lower periphery of a fixed die plate according to still another embodiment of the present invention.

9 is a schematic diagram showing a modified example of FIG.

FIG. 10 is an enlarged schematic view showing the lower periphery of a fixed die plate according to still another embodiment of the present invention.

FIG. 11 is a front view showing an outline of a mold clamping device in an injection molding machine showing a conventional example.

[Explanation of symbols]

 21 base (molding machine body frame) 23, 49, 57, 59, 63 fixed die plate 23b, 49b lower end surface 25 moving die plate 27 mold clamping cylinder (mold clamping drive means) 29 tie bar 31 fixed mold 33 movable mold 37 Ram 43 Slide plate (guide part) 51 Linear guide mechanism (guide part) 57a, 59a Sliding part 57b Chamfer part (notch part) 59b Step part (notch part) 61 Elastic body 65 Main body part 67 Support bracket part 67a Bottom surface 69 Support shaft

Claims (8)

[Claims] 1. A fixed die plate which holds a fixed die, a movable die plate which holds a movable die and is movable in a direction of approaching and separating from the fixed die plate, and the movable die plate. Of a precision injection molding machine equipped with a mold clamping drive means that presses against the side to perform mold clamping, and a tie bar that connects the mold clamping drive means and the fixed die plate and receives a mold clamping reaction force during mold clamping. In the mold clamping device, between the lower end surface of one of the fixed die plate and the mold clamping drive means and the molding machine body frame, the fixed die plate or the mold clamping drive means is molded by its deformation during mold clamping. A mold clamping device for a precision injection molding machine, which is provided with a guide portion that reduces sliding resistance when sliding on the machine body frame. 2. The mold clamping device of a precision injection molding machine according to claim 1, wherein the guide portion is a slide plate made of a sintered material impregnated with oil. 3. The mold clamping device for a precision injection molding machine according to claim 1, wherein the guide portion is a linear guide mechanism. 4. A fixed die plate which holds a fixed die, a movable die plate which holds a movable die and is movable in a direction of approaching and separating from the fixed die plate, and the movable die plate. Of a precision injection molding machine equipped with a mold clamping drive means that presses against the side to perform mold clamping, and a tie bar that connects the mold clamping drive means and the fixed die plate and receives a mold clamping reaction force during mold clamping. In the mold clamping device, either one of the fixed die plate and the mold clamping drive means is provided with a sliding surface which slides on the molding machine main body frame due to its deformation when the mold is clamped. A mold clamping device for a precision injection molding machine, wherein a notch is provided at a corner opposite to the die plate. 5. The mold clamping device for a precision injection molding machine according to claim 4, wherein the notch is formed by chamfering. 6. The mold clamping device for a precision injection molding machine according to claim 4, wherein the notch is formed by a step. 7. The mold clamping device of a precision injection molding machine according to claim 6, wherein an elastic body is interposed between the step portion and the molding machine body frame. 8. A fixed die plate that holds a fixed die, a movable die plate that holds a movable die and is movable in a direction of approaching and separating from the fixed die plate, and the movable die plate. Of a precision injection molding machine equipped with a mold clamping drive means that presses against the side to perform mold clamping, and a tie bar that connects the mold clamping drive means and the fixed die plate and receives a mold clamping reaction force during mold clamping. In the mold clamping device, one of the fixed die plate and the mold clamping driving means is a main body part separated from the molding machine main body frame, and a bottom surface formed separately from the main body part and the molding machine. A supporting bracket part that slides on the main body frame, and the lower part of the main body part is parallel to the upper surface of the molding machine main body frame in a direction orthogonal to the tie bar with respect to the supporting bracket part. A mold clamping device for a precision injection molding machine, wherein the mold clamping device is rotatably supported via a support shaft extending in a direction.