JP4417968B2 - Molding device for injection molding machine - Google Patents

Description

  The present invention relates to a mold clamping device of an injection molding machine, and more particularly to a mold clamping device using a C-type frame as a mold clamping frame.

  As a mold clamping device in an injection molding machine, conventionally, a mold clamping cylinder and a fixed platen are connected by four tie bars, and a movable plate arranged between the mold clamping cylinder and the fixed platen is provided along these tie bars. A mold that is pressed against a fixed plate by a mold clamping cylinder and clamped with a predetermined mold clamping force is used that is sandwiched between the movable plate and the fixed plate.

  However, in the case of this type of mold clamping device, since the mold must be taken in and out through the distance between the tie bars, the usable mold size is larger than the inner dimension between the tie bars and the tie bars. However, there is a problem that even with such a small mold, it is difficult to insert and remove the mold because the tie bar is in the way, and the workability at that time is poor.

Further, when taking out the molded product from the molding die, there is a problem that it is difficult to work due to the presence of these tie bars.
In particular, when a molded product is taken out by an automatic machine, there is a problem that it is difficult to realize automatic removal by the automatic machine due to the presence of a tie bar.

  On the other hand, as a mold clamping device of an injection molding machine, a C-type frame having a pair of receiving surfaces facing each other in the mold clamping direction and receiving reaction force of mold clamping is provided as a mold clamping frame, and a pair of receiving surfaces The clamping cylinder and the stationary platen are disposed between the movable clamping plate and the movable platen between the clamping cylinder and the stationary platen. The movable clamping plate is pressed toward the stationary platen by the clamping cylinder, It is well known that a reaction force of clamping is received by a pair of receiving surfaces of a C-shaped frame when a molding die sandwiched between fixed plates is clamped with a predetermined clamping force. .

  In a mold clamping apparatus using such a C-shaped frame, it is possible to take in and out a molding die and take in and out a molded product through an opening of the C-shaped frame without being interrupted by a tie bar. In addition to having good workability, the product can be easily taken out automatically using an automatic machine.

On the other hand, in the mold clamping device using the C-type frame, when the reaction force of the mold clamping is applied to the receiving surface of the C-type frame, the C-type frame is deformed so as to widen the opening. The problem is inherent.
7 and 8 specifically show this.

  In FIG. 7, 200 is a clamping cylinder, 202 is a stationary platen, 204 is a movable platen disposed between the clamping cylinder 200 and the stationary platen 202, 205 and 206 are pistons and piston rods in the clamping cylinder 200, A molding die 208 is sandwiched between the movable platen 204 and the fixed platen 202.

Reference numeral 210 denotes a C-shaped frame having a pair of receiving surfaces 212 facing each other in the mold clamping direction.
The mold clamping cylinder 200, the stationary platen 202, and the movable platen 204 are disposed between the receiving surfaces 212 and 212.
Here, in the C-type frame 210, one of the pair of receiving surfaces 212 is applied to the outer surface of the mold clamping cylinder 200 in the mold clamping direction, and the other is applied to the outer surface of the fixed platen 202 in the mold clamping direction. They are received by these receiving surfaces 212.

  However, in the case of the mold clamping device using the C-shaped frame 210, when the reaction force of the mold clamping acts on the C-shaped frame 210, more specifically, when acting on the pair of receiving surfaces 212 and 212 in opposite directions, FIG. As shown, the C-shaped frame 210 is deformed to widen the opening.

Thus, when the C-shaped frame 210 is deformed as described above, the outer peripheral portion (the upper portion in the drawing) of the receiving surface 212 is separated from the outer surfaces of the clamping cylinder 200 and the stationary platen 202 as shown in FIG. On the other hand, the inner part (the lower part in the figure) comes to locally and strongly contact the outer surfaces 214 and 216 of the mold clamping cylinder 200 and the stationary platen 202, so that the receiving surface 212 becomes the mold clamping cylinder 200 and the stationary platen. 202, the outer surfaces 214 and 216 of 202 are not evenly in contact with the entire surface, and accordingly, the supporting force at the time of mold clamping is not uniformly applied over the entire contact surface with respect to the mold clamping cylinder 200 and the stationary platen 202. Therefore, the clamping force of the molding die 208 becomes uneven in the vertical direction in the figure.
If the mold clamping force of the molding die 208 becomes uneven in the vertical direction in the figure, the mold clamping force, that is, the pressure applied to the product will be different between the lower part and the upper part in the figure, which will adversely affect the quality of the product. Will affect.

Conventionally, various proposals for solving such problems in a mold clamping device using a C-shaped frame have been made.
For example, Patent Document 1 below addresses such a problem, and an H-type tie rod is fixed to the front surface of a C-type frame, and the C-type frame is deformed so as to open an opening by the H-type tie rod. What has been made to prevent this is disclosed.
However, what is disclosed in Patent Document 1 is different from the present invention in that the solution is different.

Japanese Patent Laid-Open No. 10-34397

  The present invention is based on the circumstances as described above, and even when the mold is deformed such that the C-shaped frame opens the opening during mold clamping, the molding die is connected to the piston of the mold clamping cylinder via the mold clamping cylinder and the stationary platen. It is an object of the present invention to provide a mold clamping device for an injection molding machine using a C-type frame that can be clamped with a uniform mold clamping force in a direction perpendicular to the axis of the mold.

Thus, in the first aspect of the present invention , the pair of receiving surfaces of the C-shaped frame as a mold clamping frame having a pair of receiving surfaces facing each other in the mold clamping direction and receiving a reaction force of the mold clamping at the opening. A clamping cylinder and a stationary platen are disposed between the clamping cylinder and the stationary platen, and a movable platen is disposed between the clamping cylinder and the stationary platen, and the movable clamping plate is pressed toward the stationary platen by the clamping cylinder. Then, the molding die sandwiched between the movable platen and the fixed platen is clamped with a predetermined clamping force, and the reaction force of the clamping is applied to the outer surface of the clamping cylinder in the clamping direction. A mold clamping device of an injection molding machine adapted to receive the receiving surface on the mold clamping cylinder side and the receiving surface on the stationary platen side applied to the outer surface in the mold clamping direction of the stationary platen, In front of the clamping cylinder at a position offset to the same side in the direction perpendicular to the axis of the piston in the clamping cylinder A contact portion having a curved contact surface is provided on at least one of the outer surface and the receiving surface on the mold clamping cylinder side and at least one of the outer surface of the fixed platen and the receiving surface on the fixed platen side. The corresponding portion is made to contact the other side, and the mold clamping cylinder and the stationary plate are separated from the shaft center at a position biased to the side opposite to the contact portion with respect to the shaft center. The arm provided in a shape extending in the direction is connected in the mold clamping direction with a steel tension rod.

  According to a second aspect of the present invention, in the first aspect of the present invention, the coupling position of the tension rod to the mold clamping cylinder and / or the stationary platen can be adjusted in the mold clamping direction.

Effects and effects of the invention

  As described above, the present invention corresponds to at least one of the outer surface of the mold clamping cylinder and the corresponding receiving surface and the outer surface of the stationary platen at a position biased to the same side in the direction perpendicular to the axis of the piston in the mold clamping cylinder. A contact portion having a curved contact surface is provided on at least one of the receiving surfaces, and the contact portion is made to abut against the other side, and is biased to the opposite side to the contact portion with respect to the axis. In this position, the mold clamping cylinder and the stationary platen are connected in the mold clamping direction with a steel tension rod.

  In such a mold clamping apparatus of the present invention, even when the C-shaped frame is deformed so as to expand the opening due to the reaction force of mold clamping, the direction perpendicular to the axis of the piston with respect to the mold clamping cylinder and the fixed platen In other words, the receiving force, ie, the clamping force, is applied by the C-type frame evenly in the direction perpendicular to the mold clamping direction. Therefore, the mold is clamped equally in the same direction with respect to the molding die sandwiched between the movable platen and the fixed platen. The clamping force works, so that an effect can be obtained in which the product can be molded satisfactorily based on the uniform clamping force.

According to a second aspect of the present invention, the position where the tension rod is coupled to the mold clamping cylinder and / or the stationary platen can be adjusted in the mold clamping direction.
In the mold clamping device according to claim 1, if the tension rod is not provided, the mold clamping cylinder and the fixed platen when the mold clamping force is applied, the contact portion having the curved contact surface as a fulcrum, The side opposite to the contact part (the side opposite to the contact part with respect to the axial center of the piston) is separated from each other and rotates in the opening direction.

The tension rod serves to prevent the opening by connecting the clamping cylinder and the fixed plate on the side opposite to the contact portion with respect to the axial center of the piston. Even if the frame is deformed in the direction to open the opening, it works to maintain the parallelism between the clamping cylinder and the stationary platen.
However, this tension rod is slightly stretched in the axial direction due to the clamping force. The degree of elongation varies depending on the thickness of the tension rod even under the same clamping force.

  However, according to the second aspect, by setting the position of the tension rod to be connected to the clamping cylinder and / or the fixed platen in the clamping direction, that is, in the axial direction of the tension rod, the set clamping force is applied. Sometimes it can be ensured that the parallelism between the clamping cylinder and the stationary platen is maintained.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, 10 is a mold clamping device of the horizontal injection molding machine according to the present embodiment, and 12 is a C-shaped frame as a mold clamping frame constituting the main element.
Here, the C-type frame 12 includes a pair of receiving surfaces 14, 14 in the direction perpendicular to the mold clamping direction and facing each other in the mold clamping direction (left-right direction in the drawing).
A clamping cylinder 16, a stationary platen 18, and a movable platen 20 are disposed between the pair of receiving surfaces 14 and 14.

Here, the fixed platen 18 is provided with an insertion hole 42 for the nozzle 40 of the injection cylinder 38 in the injection machine as shown in FIG.
The filling of the molding material into the cavity of the molding die 32 described later is performed by injection of the molding material from the nozzle 40 inserted into the insertion hole 42.
In FIG. 2, reference numeral 44 denotes a molding material inlet.

The movable platen 20 is provided between the mold clamping cylinder 16 and the fixed platen 18 so as to be movable in the left-right direction in the figure.
The movable platen 20 is connected to the piston 30 of the mold clamping cylinder 16 via a piston rod 22 so that the movable platen 20 is pressed rightward in the drawing by the mold clamping cylinder 16.

The movable platen 20 is slidably fitted to the support rod 28 and is supported by the support rod 28 from below.
Reference numeral 32 denotes a molding die that is sandwiched between the movable platen 20 and the fixed platen 18 and molds a product in a mold-clamped state.

  The outer surface on the left side of the mold clamping cylinder 16 in the drawing and the outer surface on the right side in the drawing of the fixed platen 18, that is, each outer surface in each mold clamping direction, are surfaces perpendicular to the mold clamping direction (axial direction of the piston 30). Each of the outer surfaces is provided with a contact portion 36 having a curved contact surface 34 at a position deviated upward in the drawing by the same distance δ from the axis of the piston 30. However, the reaction force at the time of clamping is received by the receiving surface 14, that is, by the C-shaped frame 12 by hitting the pair of receiving surfaces 14 in the C-shaped frame 12.

As shown in FIGS. 2 and 3, a pair of C-shaped frames 12 are provided. Correspondingly, the contact portion 36 also has a clamping cylinder 16 at a position corresponding to each receiving surface 14. Each of the fixed plates 18 is provided with a pair.
The pair of C-shaped frames 12 are connected to each other by a connecting frame 54 as shown in FIG.

Arms 46 extend from the clamping cylinder 16 and the fixed platen 18 downward in the drawing, that is, in the direction opposite to the contact portion 14 with respect to the axial center of the piston 30, and each end of the arms 46 is The steel tension rods 48 are connected to each other.
As shown in FIG. 5, both end portions of the tension rod 48 are male screw portions 50, and nuts 52 are screwed onto the male screw portions 50 on both sides of the arm 46.
Each end of the tension rod 48 is fastened and fixed to each arm 46 by tightening these nuts 52.
Therefore, the tension rod 48 can adjust the coupling position with respect to the arm 46 in the axial direction by changing the screwing position of each nut 52 to the male threaded portion 50.

As shown in FIG. 1, the clamping cylinder 16 and the stationary platen 18 are connected to each other by a tension rod 48 at a position offset by a distance x away from the contact portion 36 with respect to the axial center of the piston 30. Has been.
Here, x is a larger value than δ described above.
A pair of tension rods 48 is provided as shown in FIG.

As shown in FIG. 4, the abutting portion 36 is composed of a separate member from the main body of the mold clamping cylinder 16, and this separate member is fixed to the main body of the mold clamping cylinder 16 by a bolt 56. Thus, a contact portion 36 is formed.
On the other hand, as shown in FIG. 4, the receiving surface 14 of the C-shaped frame 12 also has an L-shaped member 58 that is separate from the main body of the C-shaped frame 12, and the bolt 60 on the C-shaped frame 12 main body. By being attached, it is formed on the C-shaped frame 12 side.

62 is a support bolt provided so as to pass through the contact portion 36 and the center of the L-shaped member 58 and connect the main body of the mold clamping cylinder 16 and the main body of the C-shaped frame 12. It is supported in the vertical direction in FIG.
Here, the support bolt 62 is inserted through the insertion hole 64 of the main body of the mold clamping cylinder 16, and the tip thereof is screwed into the female screw portion 66 of the main body of the C-type frame 12.
In FIG. 4, reference numeral 68 denotes a cylindrical bush fitted into the contact portion 36 and the center hole 70 of the L-shaped member 58, and the support bolt 62 is provided in a state of penetrating the inside of the bush 68.

FIG. 6 shows the operation of the mold clamping device 10 of this embodiment.
In the mold clamping device 10 of this embodiment, the mold clamping cylinder 32 is sandwiched between the movable platen 20 and the fixed platen 18 by operating the mold clamping cylinder 16 and pressing the movable platen 20 in the right direction in the figure. Pressurized and clamped.
The reaction force of mold clamping at this time is received by each pair of receiving surfaces 14 of the C-shaped frame 12 with which the respective contact portions 36 of the mold clamping cylinder 16 and the stationary platen 18 are in contact.
These contact portions 36 are located at positions offset upward from the axial center of the piston 30 by a distance δ, so that they are opened in the direction indicated by the arrows in FIG. 6 below the clamping cylinder 16 and the fixed platen 18. Directional force works.

However, in this embodiment, each lower part of the clamping cylinder 16 and the fixed platen 18, more specifically, the lower end of the arm 46 extending downward from them is connected by the tension rod 48, so that the direction indicated by the arrow in the figure. The tension rod 48 receives a force to open the screen.
At this time, the tension rod 48 keeps the lower ends of the mold clamping cylinder 16 and the stationary platen 18 in a connected state while causing some axial elongation due to the tension acting on the tension rod 48.

Thus, when the tension rod 48 is stretched under a predetermined clamping force, the tension rod 48 is stretched so that the clamping cylinder 16 and the stationary platen 18 maintain parallelism. The amount is set in advance (however, the amount of elongation is a minute amount of about 1 mm, for example).
The amount of elongation is determined by the thickness of the tension rod 48, that is, its diameter. Therefore, specifically, a tension rod 48 having such a thickness that such elongation occurs is used here.

The C-type frame 12 is deformed as a whole in the direction of expanding the opening as shown by the arrow in FIG.
At this time, the receiving surface 14 of the C-shaped frame 12 originally formed a surface perpendicular to the mold clamping direction, but is inclined due to the deformation of the C-shaped frame 12. However, the inclination angle is actually very small, and the inclination of the receiving surface 14 is absorbed by the elastic deformation of the support bolt 62 and the bush 68 in FIG.

In this embodiment, there is no problem even if these receiving surfaces 14 are inclined, that is, the force acting on the clamping cylinder 16 and the fixed platen 18 from the receiving surface 14 of the C-shaped frame 12 is deformed. Therefore, the outer surfaces of the clamping cylinder 16 and the stationary platen 18 abut each receiving surface 14 at a contact portion 36 having a curved contact surface 34.
Therefore, despite the deformation of the C-shaped frame 12, the force exerted from the C-shaped frame 12 on the clamping cylinder 16 and the fixed platen 18 does not change.
For this reason, a uniform clamping force is exerted on the molding die 32 in a direction perpendicular to the clamping direction, whereby the product can be molded satisfactorily.

  In addition, when the clamping force by the clamping cylinder 16 is changed, it can be easily dealt with by replacing the tension rod 48 with one having an appropriate thickness. That is, in any case, it is possible to perform mold clamping while maintaining the parallelism between the mold clamping cylinder 16 and the stationary platen 18 at the time of mold clamping.

  Alternatively, according to the tensile force applied to the tension rod 48, the clamping position of the tension rod 48 with respect to the mold clamping cylinder 16 and each arm 46 of the stationary platen 18 is adjusted in the axial direction as shown in FIG. The parallelism between the mold clamping cylinder 16 and the stationary platen 18 can be maintained in accordance with the change in the mold clamping force by the cylinder 16.

Although the embodiment of the present invention has been described in detail above, this is merely an example.
For example, in the above-described embodiment, the contact portion 36 having the curved contact surface 34 is provided only on the mold clamping cylinder 16 and the stationary platen 18 side, but instead, this is provided on the receiving surface 14 side of the C-shaped frame 12. It is possible to provide a contact part 36 having a curved contact surface 34, or to provide a contact part 36 having a curved contact surface 34 on both of them. The present invention can be configured in various forms without departing from the scope.

It is a front view of the mold clamping device which is one embodiment of the present invention. It is a top view of the mold clamping apparatus of the embodiment. It is a bottom view of the mold clamping apparatus of the embodiment. It is a principal part enlarged view of the mold clamping apparatus of the embodiment. It is a principal part enlarged view different from FIG. 4 of the mold clamping apparatus of the embodiment. It is operation | movement explanatory drawing of the mold clamping apparatus of the embodiment. It is a figure which shows an example of the conventional mold clamping apparatus. It is a figure for demonstrating the malfunction of the shape clamping apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Clamping apparatus 12 C type | mold frame 14 Receiving surface 16 Clamping cylinder 18 Fixed plate 20 Movable plate 22 Piston rod 30 Piston 32 Molding die 34 Contact surface 36 Contact part 48 Tension rod

Claims (2)

A mold clamping cylinder and a stationary platen between the pair of receiving surfaces of a C-shaped frame as a mold clamping frame having a pair of receiving surfaces that are opposed to each other in the mold clamping direction and receive a reaction force of mold clamping at the opening. And further, a movable platen is arranged between the mold clamping cylinder and the fixed platen,
The movable platen is pressed against the fixed platen by the mold clamping cylinder, and a molding die sandwiched between the movable platen and the fixed platen is clamped with a predetermined clamping force, and the mold clamping is counteracted. The receiving surface on the mold clamping cylinder side where force is applied to the outer surface in the mold clamping direction of the mold clamping cylinder and the receiving surface on the stationary platen side applied to the outer surface in the mold clamping direction of the stationary platen In the mold clamping device of the injection molding machine, which is received by the A contact portion having a curved contact surface is provided on at least one of the receiving surface, and at least one of the outer surface of the fixed platen and the receiving surface on the fixed platen side. And it is biased to the opposite side of the contact part with respect to the axis. In location, injection, characterized in that the said clamping cylinder and said fixed plate, and in the arm which is provided in a form extending in axial sincerely away direction each at a steel tension rods connected to the mold clamping direction Mold clamping device for molding machine.   2. The mold clamping apparatus for an injection molding machine according to claim 1, wherein the position of the tension rod coupled to the mold clamping cylinder and / or the stationary platen is adjustable in the mold clamping direction.

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