JPH0289609A - Mold clamping device - Google Patents

Abstract

PURPOSE:To make it possible to keep the favorable parallelism between a fixed platen and a movable platen by a method wherein the opening and closing and clamping of molds done between the fixed plate and the movable platen by stretching and contracting a link mechanism, which consists of a first and a second link members and is arranged between a pressure platen and the movable platen, and, at the same time, the length of the second link member is adjusted. CONSTITUTION:A link mechanism, which consists of a first link member 47 and a second link member 34 connected to each other, is interposed between a pressure platen 12 and a movable platen 16. The movable platen 16 is moved on the basis of the stretching and bending actions of the link mechanism. At the same time, the adjustment of mold thickness for bringing the posture of the link mechanism at mold clamping to nearly constant one at all times regardless of mold thickness is done on the basis of the adjustment of the length of the link mechanism at its stretched state (the distance between the center of a connecting shaft 32 and that of a shaft 60) by adjusting the length of the link member 34. Thus, when the parallelism between a fixed platen 10 and the movable platen 16 is set to be high in advance, the parallelism between the fixed platen 10 and the movable platen 16 can be kept high at all times regardless of the mold thickness adjusting operation in response to the thicknesses of molds 44 and 46.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a mold clamping device for opening, closing, and clamping a mold, and in particular, a mold clamping device that moves a movable platen toward and away from a fixed platen via a link mechanism. This invention relates to a mold clamping device for opening, closing, and clamping a mold.

(Background Art) A mold clamping device that opens, closes, and clamps a mold generally has a structure in which a movable platen is slidably supported by a stay that connects a pressure receiving platen and a fixed platen. . By moving the movable plate toward and away from the fixed plate, the mold is opened and closed and clamped between the fixed plate and the movable plate.

By the way, as a type of mold clamping device, a toggle link mechanism is conventionally interposed between the pressure receiving plate and the movable plate, and the movable plate is moved via the toggle link mechanism to open and close the mold. A mold clamping device that performs pressure clamping is known, but in mold clamping devices that use such a link mechanism, in order to ensure that the clamping force always acts effectively on the movable platen, the mold clamping device is It is necessary to ensure that the link mechanism always maintains a substantially constant posture during compression, regardless of the thickness of the mold.

Therefore, in a conventional mold clamping device using this type of link mechanism, a screw mechanism is provided between the pressure receiving plate and each stay for moving the pressure receiving plate toward and away from the fixed plate. A mold thickness adjustment mechanism is employed in which the relative distance between the pressure receiving plate and the fixed plate is changed by means of these screw mechanisms. By adjusting the relative distance between the pressure receiving plate and the fixed plate according to the thickness of the mold, the link mechanism can be kept in a substantially constant posture regardless of the thickness of the mold when the mold is pressed. This is because it becomes possible to always effectively apply a clamping force to the movable platen.

However, in conventional mold clamping devices that adopt such a mold thickness adjustment mechanism, the screw pitch of the screw mechanism provided between the pressure plate and each stay and the amount of rotation of these screw mechanisms when moving the pressure plate are not accurate. If they do not match well, there will be problems with the parallelism between the pressure receiving plate and the fixed plate, and even the parallelism between the movable plate and the fixed plate.Therefore, it is extremely important to maintain a high degree of parallelism between them. There were some difficult problems.

(Problem to be Solved) The present invention was made against the background of the above, and its object is to provide a mold clamping device of a type in which a movable platen is moved toward and away from a fixed platen via a link mechanism. Even if the mold thickness is adjusted according to the mold thickness so that the posture of the link mechanism during mold clamping is approximately constant regardless of the mold thickness, the movable platen and An object of the present invention is to provide a mold clamping device that can always maintain a high degree of parallelism with a fixed plate.

(Solution Means) In order to solve the problem, in the present invention, the movable plate is slidably supported on the stay that connects the pressure receiving plate and the fixed plate, as described above, and In a mold clamping device that opens and closes a mold and clamps a mold between a fixed platen and a movable platen by moving the movable platen toward and away from the fixed platen, the first link member and the second link member A link mechanism is rotatably connected to each other at one end of the first link member, and the other end of the first link member is rotatably connected to the pressure receiving plate side. A first link member rotatably connected to the movable platen on the end side, interposed between the pressure receiving plate and the movable platen, and causing the first link member to rotate about the rotation axis of the pressure receiving plate side. By providing one rotational driving means and expanding and bending both link members of the link mechanism by the first rotational driving means, the movable platen is moved toward and away from the fixed platen. The second link member is connected to a screw mechanism consisting of a male screw member and a female screw member that are screwed together, and one screw member of the screw mechanism is rotated relative to the other screw member, and the second link member is connected to the second link member. a second rotational drive means for changing the length of the link member, and the length of the link mechanism when extended can be adjusted based on the operation of the second rotational drive means. That's what I did.

(Function) In such a mold clamping device, the first link member is rotated by the first rotation drive means around the rotation axis on the pressure receiving plate side, and the link mechanism is extended. The movable platen is moved closer to the fixed platen. and,
In order to effectively apply a clamping force to the movable platen, the mold is clamped while the link mechanism is almost fully extended.

By the way, in the mold clamping device according to the present invention, by relatively rotating both screw members of the screw mechanism based on the operation of the second rotational drive means, the length of the second link member and, by extension, the length of the second link member can be adjusted in a constant posture. In other words, the length of the link mechanism can be changed while the angle formed by both link members is constant. In other words, by relatively rotating both screw members of the screw mechanism using the second rotation drive means, the clamping force is effectively applied to the movable platen. The relative distance between the movable platen and the fixed platen in the posture of the link mechanism can be changed.

Therefore, if the length of the second link member is adjusted so that the relative distance between the fixed platen and the movable platen when the link mechanism is almost fully extended corresponds to the mold thickness of the mold, the mold Regardless of the mold thickness, the mold can be clamped with the link mechanism almost fully extended, that is, with the clamping force effectively acting on the movable platen. Regardless of the mold thickness, the clamping force can always be effectively applied to the mold.

In the mold clamping device according to the present invention, the length of the set of link mechanisms that move the movable platen by the stretching action of both link members is adjusted based solely on the adjustment of the extended length of the pair of link mechanisms. Since the mold thickness is adjusted so that the posture of the link mechanism during mold clamping is always approximately constant regardless of the mold thickness of the mold, the mold thickness can be adjusted according to the mold thickness of the mold. Regardless of the adjustment operation, the parallelism between the fixed plate and the movable plate can always be maintained at a high level.

(Example) Hereinafter, in order to clarify the present invention more specifically,
One embodiment thereof will be described in detail based on the drawings.

First, FIG. 1 and FIG. 2 respectively show a partially cutaway front sectional view and a partially cutaway plan view of the mold clamping device according to the present invention in a mold clamping state. FIG. 3 shows a partially cutaway plan view of the mold clamping device in the mold open state. In those figures, 1
0.12 is a fixed plate and a pressure receiving plate respectively installed upright on the base, and four stays 1 parallel to each other are attached at the four corners.
4, and are arranged so as to face each other with a sufficiently high degree of parallelism. Between the fixed platen 10 and the pressure receiving plate 12, a movable platen 16 is disposed parallel to the fixed platen 10 and is supported by stays 14 slidably inserted into the four corners. A guide plate 18 is disposed between the plate 16 and the pressure receiving plate 12 in parallel to the movable plate 16, supported by stays 14 slidably inserted into the four corners, similarly to the movable plate 16. There is.

The movable platen 16 and the guide plate 18 are fixed to each other by a guide port 27 that guides the ejector bar 24 via an ejector box 26 that holds the ejector bar 24 to which the ejector pin 22 is attached. Further, the movable platen 16 and the guide plate 18 are both supported by the stay 14 via an inner sleeve 2021 that is fitted to the stay 14 with high precision.

Here, a cutout hole 28 is provided in the center of the guide plate.
A pair of arms 30 and 30 provided on the back surface of the ejector box 26 pass through the cutout hole 28 of the guide plate 18 and extend toward the pressure receiving plate 12 side. A connecting shaft 32 is provided with both ends supported by the arms 30, 30, and a second link member 34 is rotatably connected to the connecting shaft 32 at one end.

On the other hand, brackets 36 and 37 are arranged on the pressure receiving plate 12 so as to extend parallel to each other toward the guide plate 1 side, and both ends of a connecting shaft portion 38 are rotatably attached to these brackets 36 and 37. A first link member 42 is provided with a structure in which a pair of arm portions 40 and 40 extend parallel to each other from the connecting shaft portion 38.

Then, with respect to the other end of the second link member 34,
The first link member 42 is rotatably connected at the distal end of the arm portion 40.40 so that the link members 34.42 can expand and contract. Due to the operation, the movable platen 16 approaches and approaches the pressure receiving plate 12 and, by extension, the fixed platen 1o.
They are now forced to move away.

Here, the connecting shaft portion 3 of the first link member 42 is
8 is connected to an electric servo motor 50 via a reducer 48, and based on the rotational operation of the electric servo motor 50, the link members 34 and 42 are extended and compressed, and the movable platen I6 approaches the fixed platen 0. - The fixed mold 44 and the movable platen 1 mounted on the fixed platen 10 are separated by the separation operation.
Opening/closing and pressing operations with a movable mold 46 mounted on the mold 2 are performed. As is clear from this, here, the link members 34 and 42 constitute a link mechanism, and the electric servo motor 50 constitutes the tenth rotation means.

In addition, as is clear from FIG. 1, the first link member 4
One end of the second connecting shaft portion 38 is rotatably supported by the bracket 37 via a speed reducer 48. Moreover, here, as the electric servo motor 50, one incorporating a non-excitation operated electromagnetic brake is employed. Furthermore, in FIG. 1, 51 is a rotary encoder for detecting the amount of rotation of the electric servo motor 50 and detecting the moving position of the movable platen 16 when the mold is opened and closed.

By the way, the second link member 34 includes a screw mechanism consisting of a male screw member 52 and a female screw member 54 screwed together, a screw mechanism holder 56 that holds the screw mechanism, and a screw mechanism holder 56 that holds the screw mechanism. The electric servo motor 58 is mounted to rotate the male screw member 52 of the screw mechanism relative to the female screw member 54. The length of the link can be expanded or contracted based on the relative rotational action.

That is, the screw mechanism holder 56 has a cylindrical shape with a bottom, and the first link member 4 is connected to the bottom wall of the screw mechanism holder 56.
It is rotatably connected to the second arm portion 40.40.

A female screw member 54, which is rotatably connected to the connecting shaft 32 at one end, is slidably inserted into the inner hole of the screw mechanism holder 56.

Note that, in the screw mechanism holder 56, a pair of shafts 60.60 coaxially extending laterally from the bottom wall of the bottomed cylindrical portion of the screw mechanism holder 56 is connected to the arm portion 40.40. It is rotatably connected to the first link member 42 by being fitted into a sliding sleeve 62, 62 held and disposed at the tip. Further, the female screw member 54 is connected to the connecting shaft 32 via a sliding sleeve 64.

The female screw member 54 has a bottomed hole 65 that opens on the bottom wall side of the screw mechanism holder 56, and a female screw portion 66 is provided on the inner peripheral surface of the bottomed hole 65. The male threaded member 52 is screwed into the female threaded portion 66 of the female threaded member 54 by a male threaded portion 68 .

This male screw member 52 penetrates the bottom wall of the bottomed cylindrical portion of the screw mechanism holder 56, and is arranged to be rotatable and immovable in the axial direction with respect to the screw mechanism holder 56,
A sprocket 70 is disposed at the end protruding from the screw mechanism holder 56. The sprocket 70 and the output shaft of the electric servo motor 58 mounted on the screw mechanism holder 56, more specifically, the output shaft of a reducer 72 that decelerates and outputs the rotational force of the electric servo motor 58, are provided. A chain 76 is connected between the sprocket 74 and the
(omitted in FIG. 1) is passed, thereby causing the male threaded member 52 to be connected to the threaded mechanism holder 56.
Furthermore, the electric servo motor 5
It is designed to be relatively rotated based on the rotational force of 8.

Therefore, when the male threaded member 52 is rotationally driven by the electric servo motor 58, the male threaded member 52 is rotated relative to the female threaded member 54.
The length of the screw mechanism consisting of the female screw member 54 and the female screw member 54 and the length of the fitted body of the female screw member 54 and the screw mechanism holder 56 expand and contract, and the length of the second link member 34 is changed. . As is clear from this, here, the electric servo motor constitutes the second rotational drive means.

In addition, in FIGS. 2 and 3, 78 is a linear encoder for detecting the amount of expansion of the second link member 34, and is disposed astride the female screw member 54 and the screw mechanism holder 56. ing. Also, in those figures, 80
is a limit switch for detecting when the link mechanism is almost fully extended and both link members 34 and 42 of the link mechanism are expanded to an angle (posture) that allows effective clamping force to be applied to the movable platen 16. Here, the female screw member 5
4, that is, the rotation of the second link member 34 by a certain amount around the connecting shaft 32 is detected by the limit switch 80, and the clamping state of the molds 44, 46 is detected.

By the way, in such a mold clamping device, when replacing the molds 44 and 46 having different mold thicknesses, the replacement work of the molds 44 and 46 is performed, for example, as follows.

That is, when replacing the molds 44 and 46, first, from the mold open state as shown in FIG.
0 to extend the link mechanism (link member 34
．． 42), and as shown in FIGS. 1 and 2, the old molds 44 and 46 to be replaced are brought into close contact.

Then, in this close contact state, the fixed platen 10 of the molds 44 and 46
Then, the fixed state to the movable platen 16 is released, and after the fixed state is released, the movable platen 16 is retreated to the mold opening position again based on the drive of the electric servo motor 50.

The retracted position of the movable platen 16 when the mold is opened is determined by the contact of the first link member 42 with a stopper 82 fixed to the pressure receiving plate 12, as shown in FIG. stipulated.

Next, after the movable platen 16 is moved back to the mold opening position,
The old molds 44 and 46 are taken out from between the fixed platen IO and the movable platen 16, and a new mold 4446 is set in their place. Here, if the mold thickness of the cutting mold 44.46 is smaller than the mold thickness of the old mold 44.46, it may be left as is, but usually,
Regardless of the thickness of the cutting die 44 and 46, the male screw member 52 is rotated relative to the female screw member 54 in 5 days using the electric servo motor, and the length of the second link member 34 is the shortest length. is set to In this state, the link members 34 and 42 are expanded based on the drive of the electric servo motor 50 until the limit switch 80 is activated.

After the expansion operation of the link member is completed, the male screw member 52 is rotated by the electric servo motor 58, the second link member 34 is extended, and the movable platen 16 is advanced until it comes into close contact with the mold 46. , the molds 44 and 46 are attached to the stationary platen 10 and the movable platen 16, respectively, in a close contact state. However, in this state, the molds 44 and 46 are simply closed and no clamping force is generated, so the electric servo motor 50 moves the movable platen 16 by the stroke required to generate clamping force. The molds 44 and 46 are opened by retreating, and then the second link member 34 is extended by the electric servo motor 58 until the molds 44 and 46 are brought into close contact with each other again and the molds are closed. This completes the replacement work of the old and new molds 44 and 46. The closed state of the molds 44 and 46 is normally detected by detecting an increase in the drive current (load) of the electric servo motor 58.

In the mold clamping device of this embodiment, if the old and new molds 4446 are replaced as described above, the molds 4446
．． In normal molding conditions using the molds 44.46, the limit switch 80 is activated.
Therefore, the molds 44,
A link mechanism in which both link members 34 and 42 of the link mechanism are expanded to an angle where the clamping force based on the rotational force of the electric servo motor 50 is effectively applied to the movable platen 16 regardless of the mold thickness of the link mechanism 46. The molds 44 and 46 are always pressed in a substantially constant posture in which the molds 44 and 46 are substantially fully extended.

Here, as described above, the link member 34.4
The movable platen 16 is moved based on the expansion action of a pair of link mechanisms consisting of two link mechanisms, and the length of the second link member 34 is adjusted so that when the link mechanism is extended, Based solely on adjusting the length (distance between the axes of the connecting shaft 32 and the shaft 60.60), the posture of the link mechanism during mold clamping is always kept approximately constant regardless of the mold thickness of the mold. Since the mold thickness is adjusted to achieve this, by setting the parallelism between the fixed platen 10 and the movable platen 16 to be high in advance, it is possible to adjust the mold thickness according to the mold thickness of the molds 44 and 46. Regardless of the mold thickness adjustment operation, the fixed platen 10 and the movable platen 16 can always be maintained at a high degree of parallelism.

In this embodiment, the movable platen 16 is fixed to the guide plate 18 which is slidably supported by the stay 14 like the movable platen 16 via the ejector box 26, so that the movable mold There is an advantage that the tilting of the movable platen 16 due to the attachment of the movable platen 46 is small, so that the movable platen 16 and the fixed platen 10 can be maintained in a high degree of parallelism.

Further, in this embodiment, the link mechanism is substantially extended when the molds 44 and 46 are in the clamped state, and the pressing force based on the rotational force of the electric servo motor 50 acts extremely effectively on the movable platen 16. This has the advantage that the torque setting of the electric servo motor 50 can be lowered to reduce power consumption when the molds 44 and 46 are held in a clamped state. Since a device equipped with a brake is adopted, power consumption is also reduced by interrupting the power supply to the electromagnetic brake to prevent the movable platen 16 from retreating and holding the molds 44 and 46 clamped. It has the advantage of being possible. Furthermore, it is possible to hold the molds 44 and 46 clamped by lowering the torque setting of the electric servo motor 50 while preventing the movable platen 16 from retreating by blocking power to the electromagnetic brake. , Power consumption can also be advantageously reduced in this way.

In addition, since the electric servo motor 50 is equipped with a non-excitation type electromagnetic brake, in the event that the main power supply is cut off during molding operation, the braking force of the non-excitation type electromagnetic brake is reduced. Based on this, there is an advantage that the mold opening/closing operation can be automatically and forcibly stopped, and if the safety door is opened during molding operation or the emergency stop button is pressed, the mold opening/closing operation can be forcibly stopped. There is also the advantage that a forced stop mechanism for stopping can be easily constructed.

Although one embodiment of the present invention has been described in detail above, this is a literal illustration, and the present invention is not limited to such a specific example, and within the scope of the spirit thereof,
It goes without saying that the present invention can be implemented with various changes, modifications, improvements, etc.

For example, in the embodiment described above, both link members 34 of the link mechanism when clamping the mold are used to effectively apply clamping force to the movable platen 16.
．． The expanded state of 42 is the connecting shaft 3 of the second link member 42.
This is detected by detecting the rotation position of two rotations with the limit switch 80, but the rotation position between the first link member 42 and the second link member 34 (more precisely, the screw mechanism holder 56) is detected by the limit switch 80. A relative rotation amount detection device is provided between them to detect the relative rotation amount, and from the rotation amount detected by the relative rotation amount detection device, the expansion of both link members 34 and 42 in the mold clamped state is determined. It is also possible to detect the state.

Further, in the embodiment described above, the female screw member 54 is connected to the connecting shaft 32, while the male screw member 52 is connected to the screw mechanism holder 56.
The length of the second link member 34 is changed by rotationally driving the male screw member 52 held by the screw mechanism holder 56 by an electric servo motor 58 serving as a second rotation driving means. However, while connecting the male screw member to the connecting shaft 32,
The female screw member is held by a screw mechanism holder 56, and the female screw member held by the screw mechanism holder 56 is rotationally driven by an electric servo motor 58 to change the length of the second link member 34. It is also possible.

(Effects of the Invention) As explained above, the mold clamping device according to the present invention includes first and second link members rotatably connected to each other at one end between the pressure receiving plate and the movable plate. A set of link mechanisms consisting of are interposed, and the mold is opened/closed and clamped between the fixed plate and the movable plate by movement of the movable plate based on the colic of the link mechanism,
By adjusting the length of the second link member of the link mechanism, the mold thickness can be adjusted so that the posture of the link mechanism during mold clamping is always approximately constant regardless of the mold thickness of the mold. Because of this, the parallelism between the stationary plate and the movable plate can be maintained extremely well regardless of the mold thickness adjustment operation according to the mold thickness, and therefore, molded products of excellent quality can be obtained. It has the advantage of being able to be stably molded.

[Brief explanation of drawings]

1 and 2 are respectively a front partially cutaway sectional view and a plan partially cutaway sectional view of the mold clamping device according to the present invention in a mold clamping state, and FIG. FIG. 2 is a partially cutaway plan view of the mold clamping device in the mold open state. 10: Fixed plate 12: Pressure receiving plate 14 Nisty 16: Movable plate 18 Guide plate 26: Ejector box 34: Second link member 42: First link member 44.46: Mold 50: Electric servo motor (first (Rotation drive means) 52: Male thread member 54: Male thread member 56: Screw mechanism holder

Claims (1)

[Claims] A movable platen is slidably supported by a stay that connects a pressure receiving plate and a fixed platen, and the movable platen is moved toward and away from the fixed platen, thereby connecting the fixed platen and the movable platen. A mold clamping device for opening, closing, and clamping a mold with a panel has a structure in which a first link member and a second link member are rotatably connected to each other at one end side. A link mechanism is rotatably connected to the pressure receiving plate at the other end of the first link member, and rotatably connected to the movable plate at the other end of the second link member. A first rotation driving means is provided between the pressure receiving plate and the movable plate and rotating the first link member about the rotation axis of the pressure receiving plate, and the link mechanism By expanding and bending both link members by the first rotation driving means, the movable platen is moved toward and away from the fixed platen, while the second link member is moved toward and away from the fixed platen. A screw mechanism consisting of a male screw member and a female screw member screwed together, and changing the length of the second link member by rotating one screw member of the screw mechanism relative to the other screw member. and a second rotational drive means for causing the link mechanism to extend, and the length of the link mechanism when extended can be adjusted based on the operation of the second rotational drive means. Tightening device.