JPS63242618A - Mold clamping device in injection molder - Google Patents

Abstract

PURPOSE:To ensure large mold clamping force in molds and to speed up the shifting rate of a movable platen by a structure wherein a first nut member, which is arranged so as to be positionally fixed to a movable platen, a second nut member, which is rotatably supported by a stationary member positionally fixed to a fixed platen, ball screw members and a first and a second braking mechanisms are contained in a device. CONSTITUTION:Under the condition that an electromagnetic braking mechanism 44 is set under the state that a braking effect is produced and an electromagnetic braking mechanism 64 is set under the state that no braking effect is produced, a motor-driven servo motor 58 is driven so as to rotate in the direction to close mold. As a result, a movable platen 18 is moved to approach a fixed platen 10 at the speed of a screw having a lead, which is the sum of the lead of the right-handed screw part 28 of a ball screw 26 and that of the left-handed screw part 30. The mold clamping action is performed by driving a electric servo motor 38 under the condition that the electromagnetic braking mechanism 44 is set under the state that no braking effect is produced and the electromagnetic braking mechanism 64 is set under the state that a braking effect is produced so as to rotate a second ball screw nut 32 in the direction to close mold. The ball screw 26 and, in its turn, the movable platen 18 is pressed to the fixed platen 10 side due to the rotation relative to a second ball screw nut 32. Since the lead of the left-handed screw part 30 is small, the movable platen 18 is pressed by large pressing force.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a mold clamping device for an injection molding machine, and more particularly to a mold clamping device of a type that uses a ball screw mechanism as a moving mechanism for a movable platen.

(Prior art) It is equipped with a fixed platen and a movable platen that can approach and move away from the fixed platen, and by moving the movable platen toward and away from the fixed platen, the movement between the movable platen and the fixed platen is made. Among mold clamping devices for injection molding machines designed to clamp a mold, there is one that uses the side of a ball screw machine as a moving mechanism for moving a movable platen with respect to a fixed platen. For example, a mold clamping device disclosed in Japanese Unexamined Patent Publication No. 59-187826 is one example.

By the way, in a mold clamping device (hereinafter simply referred to as a mold clamping device) that employs a ball screw mechanism as a moving mechanism for such a movable platen, conventionally, as disclosed in the above publication, a ball screw member and a nut member that constitute the ball screw mechanism are used. The movable platen was moved by fixing one member to the movable platen, connecting the other member to a rotational drive device, and rotating the other member by the rotational drive device.

(Problem) However, in the conventional mold clamping device with this structure,
It is difficult to simultaneously satisfy the mold clamping function and high-speed mold opening/closing function required of a mold clamping device, and if you try to satisfy both at the same time, the noise generated during high-speed mold opening and closing will become extremely large. , there was a problem that it significantly degraded the working environment.

□ In other words, in the conventional mold clamping device with the structure described above, reducing the lead of the ball screw mechanism makes it easier to secure a large mold clamping force when clamping the mold, but it is difficult to open and close the mold. At times, there was a problem in that it was difficult to increase the moving speed of the movable platen, and conversely, increasing the lead of the ball screw mechanism made it easier to move the movable platen at high speed, but at the same time There was a problem in that it became difficult to secure a large mold clamping force. Furthermore, by reducing the lead of the ball screw mechanism and rotating the other member at high speed, a large mold clamping force can be secured when the mold is clamped, and the moving speed of the movable platen when opening and closing the mold can be increased. However, in this case, the relative rotational speed between the ball screw member and the nut member increases significantly when the movable platen moves at high speed when opening and closing the mold. As a result, it was inevitable that the noise generated by the ball screw mechanism would become significantly louder.

(Solution Means) Against the background of the above-mentioned circumstances, the present invention simultaneously ensures a large clamping force when clamping a mold and increases the moving speed of the movable platen when opening and closing the mold. This was done in order to provide a mold clamping device for an injection molding machine that can increase the moving speed of the movable platen without making a lot of noise. , as described above, is equipped with a fixed platen and a movable platen that is provided so as to be able to approach and move away from the fixed platen, and by moving the movable platen toward and away from the fixed platen, the distance between the movable platen and the fixed platen is increased. A mold clamping device in an injection molding machine is configured to clamp a mold with (a) a first nut member disposed in a fixed position with respect to a movable platen, and (b) with respect to a fixed platen. a second nut member rotatably supported by a stationary member whose position is fixed, and (c) a right-hand threaded portion and a base threaded portion, and one of the threaded portions is attached to the second nut member;
and (d) a first rotational drive device that rotationally drives the second nut member; a first brake mechanism that forcibly prevents rotation of the second nut member; (f) a second rotational drive device that rotationally drives the ball screw member;
g) A second brake mechanism for forcibly blocking rotation of the ball screw member.

(Operation/Effect) According to such a mold clamping device, for example, by rotating the second nut member while the rotation of the ball screw member is prevented by the second brake mechanism, the second nut member and the ball screw can be connected to each other by rotating the second nut member. Based on the relative rotation with the member, the ball screw member and, by extension, the movable platen can be moved relative to the fixed platen. Therefore, if the lead of the ball screw mechanism consisting of the second nut member and the threaded portion of the ball screw member is made small, the mold can be A large mold clamping force can be easily secured during mold clamping.

On the other hand, if the ball screw member is directly rotated by the second rotational drive device while the rotation of the second nut member is prevented by the first brake mechanism, the ball screw member can be rotated by the right threaded portion and the left threaded portion of the ball screw member. are screwed into the first and second nut members, respectively, and therefore, based on the relative rotation of both the corresponding threaded portion and the nut member, that is, the rotation of each threaded portion of the ball screw member and each corresponding nut member. The movable platen can be moved at a speed corresponding to the sum of the leads of the two ball screw mechanisms consisting of the members. In other words, in order to secure the mold clamping force, even if the lead of one ball screw mechanism is made small, the lead of the ball screw mechanism as a whole can be made sufficiently large. The moving speed of the movable platen, that is, the mold opening/closing speed of the mold can be increased without increasing the relative rotational speed with the nut member.

Therefore, the moving speed of the movable platen can be increased without making much noise.

As described above, according to the present invention, it is possible to simultaneously secure the mold clamping force when closing the mold and increase the moving speed of the movable platen when opening and closing the mold. Since there is no large noise when opening and closing, it is possible to avoid deterioration of the working environment.

In addition, according to the present invention, since it is possible to satisfactorily suppress the increase in the relative rotational speed between the ball screw member and each nut member, it is possible to satisfactorily suppress the wear of the threaded portion of each ball screw mechanism constituted by them, Another advantage is that its lifespan can be greatly improved.

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

First, FIG. 1 shows an example of a mold clamping device according to the present invention, in which 10 and 12 are a fixed plate to which a fixed mold 11 is attached, and a pressure receiving plate as a stationary member, respectively. They are installed on a base 16 in a state where they face each other and are connected to each other by a stay 14. And those fixed platen 10 and pressure receiving plate 1
A movable platen 18 is slidably disposed to face the fixed platen 10, and a movable platen 20 is slidably disposed to face the receiving pressure ff112. . In addition, in the figure, 19 is a movable mold attached to the movable platen 1B.

A cylindrical portion 22 of a predetermined length is provided on the surface of the movable platen 18 opposite to the mounting surface of the movable mold 19 and extends toward the movable platen 20 side.
is provided, and a first pole screw nut 24, which is a first nut member, is fixedly located at the tip of the cylindrical portion 22. A ball screw 26 is screwed into the first ball screw nut 24 at a right-hand threaded portion 28 formed at one end of the first ball screw nut 24 with a ball screw structure having a relatively large lead.

The ball screw 26 penetrates the movable platen 20 and the pressure receiving plate 12 and is disposed in parallel with the stay 14, and is located at the end on the pressure receiving plate 12 side and includes a left-handed threaded portion 30@. and,
A second pole screw nut 32 is screwed into the left-hand threaded portion 30 of the ball screw 26 with a ball screw structure having a relatively small lead.

A pressure receiving plate 12 is provided on the outer peripheral surface of the second pole screw nut 32.
An actuating sleeve 34 is fixedly supported rotatably and axially immovably by the actuating sleeve 3.
A toothed pulley 36 is fixedly provided on the outer peripheral surface of 4. A timing belt 42 is passed between the toothed pulley 36 and a toothed boot IJ40 attached to the motor shaft of the electric servo motor 38, and this causes the second pole screw nut 32 to be Servo motor 3
8 for rotational driving. Note that the electric servo motor 38, as shown in the figure,
It is mounted and installed on the pressure receiving panel 12. Furthermore, as is clear from the above description, here, the second pole screw nut 32 and the operating sleeve 34 operate the second nut member, and the electric servo motor 38 operates the first rotational drive device.
Each consists of

Further, an electromagnetic brake mechanism 44 is disposed between the actuation sleeve 34 and the pressure receiving plate 12, and the actuation sleeve 34
Therefore, rotation of the second pole screw nut 32 can be forcibly prevented by the electromagnetic brake mechanism 44.

Note that the 1!1 magnetic brake mechanism 44 is of a so-called spring close type.

When the coil (not shown) is in a non-energized state, the movable member 46
is pressed against the fixed member 50 by the biasing force of the spring 48, thereby preventing rotation of the actuating sleeve 34, and when the coil is energized, the movable member 46 resists the biasing force of the spring 48. By being separated from the fixed member 50, the actuating sleeve 3
4 rotations are allowed. Further, in this embodiment, the electromagnetic brake mechanism 44 constitutes a first brake mechanism.

On the other hand, the right threaded portion 28 and the left threaded portion 3 of the ball screw 26
An actuating sleeve 52, which is rotatably but immovably supported in the axial direction by the movable platen 20, is fixed to the non-threaded portion between the movable plate 20 and the movable plate 20 via a predetermined connecting sleeve 54. A toothed pulley 56 is fixed to the outer peripheral surface of the operating sleeve 52, and a timing belt 62 is hooked between the toothed pulley 56 and a toothed boolean 1J60 attached to the motor shaft of the electric servo motor 58. has been passed. The ball screw 26 can be directly rotationally driven by the electric servo motor 58.

As shown, the electric servo motor 58 is mounted on the movable board 20 and is configured to move integrally with the ball screw 26 in the axial direction of the ball screw 26. Moreover, as is clear from the above description, the electric servo motor 58 constitutes the second rotational drive device here.

Moreover, between the operating sleeve 52 and the movable platen 20,
A spring-close type electromagnetic brake mechanism 64 similar to the electromagnetic brake mechanism 44 is provided, and the rotation of the actuating sleeve 52 and, by extension, the ball screw 26 can be forcibly prevented by the electromagnetic brake mechanism 64. . Here, the electromagnetic brake mechanism 64 constitutes a second brake mechanism.

Next, an example of the operation when the device of this embodiment performs mold opening/closing and mold clamping operations of the molds 11 and 19 will be described.

That is, when closing the molds 11 and 19 from the open state shown in FIG. 64 is set to a non-braking state (energized state),
The electric servo motor 58 is driven to rotate in the mold closing direction. In this way, since the ball screw 26 rotates relative to the first and second ball screw nuts 24 and 32 in the mold closing direction, the movable platen 18 rotates relative to the fixed platen 10 at the right-hand threaded portion of the ball screw 26. Add the lead 11I of 28 and the lead LL of the left-hand threaded part 30,
B + IIL ), and therefore the mold 11.19 is closed at a speed significantly higher than the rotational speed of the ball screw 26.

In addition, when performing a mold opening operation from the mold closing state of the mold 11.19, the electromagnetic brake mechanism 44.64 is set to the same state as in the case of the mold closing operation, and the electric servo motor 58
What is necessary is to rotate it in the mold opening direction. In this way, the movable platen 18 can be moved to the lead I as in the mold closing operation described above.
t (=11 +AL), and therefore the mold opening speed of the mold 11.19 can be made significantly higher than the rotational speed of the ball screw 26.

In other words, according to this embodiment, when the mold 11.19 is opened and closed, the movable platen does not have to rotate the ball screw 26 at such a high speed relative to the first and second pole screw nuts 24.32. 18 can be moved at a sufficiently high speed, and therefore the molds 11 and 19 can be opened and closed at high speed without generating a large amount of noise.

Note that when the molds 11 and 19 are opened and closed, the electromagnetic brake mechanism 44 is set to a non-braking state, and the electric servo motor 38 rotates the second ball screw nut 34 in the mold closing direction and the mold opening direction, respectively. By doing so, it becomes possible to move the movable platen 18 at a speed corresponding to each lead (1 m + 21.), and the mold 11.
It becomes possible to further increase the mold opening/closing speed of No. 19.

However, in this case, the rotational speed of the ball screw 26 relative to the second pole screw nut 32 is twice that of the above-mentioned case, and the noise increases accordingly. The rotational speed can be made sufficiently small compared to the moving speed of the motor, so the noise does not become that large.

On the other hand, when performing a mold clamping operation after closing the mold 11.19, the electromagnetic brake mechanism 44 is placed in a non-braking state and the electromagnetic brake mechanism 64 is placed in a braking state, contrary to the case during the mold opening/closing operation. Once set, the electric servo motor 38 is driven to rotate the second pole screw nut 32 in the mold closing direction (mold clamping direction). In this way, the ball screw 26,
As a result, the movable platen 18 is pressed toward the fixed platen 10 based on the relative rotation with the second pole screw nut 32, and as described above, the left side of the ball screw 26 screwed into the second pole screw nut 32 is pressed against the movable platen 18. Since the lead 6L of the threaded portion 30 is made small, the movable platen 18 can be pressed against the fixed platen 10 with a sufficiently large pressing force (mold clamping force).

In addition, during such mold clamping operation, both electromagnetic brake mechanisms 44 and 64 are normally set to a braking state when the desired mold clamping force is obtained, and thereby the mold clamping force is maintained. Become.

Further, after the mold clamping operation is completed, the electromagnetic brake mechanism 44 is normally operated under the driving state of the electric servo motor 38.
After the braking state is released and the movable platen 18 is retreated to the mold clamping start position under the driving state of the electric servo motor 38, the mold opening operation by the electric servo motor 58 is performed.

As explained above, according to the mold clamping device according to this embodiment, sufficient mold clamping force is obtained when clamping the molds 11 and 19, while the movable platen 18 is moved at high speed when opening and closing the molds. It can be moved. Moreover, it does not generate large noise when opening and closing at high speed.
This makes it possible to effectively avoid deterioration of the working environment.

Further, according to the mold clamping device according to this embodiment, as described above, the ball screw 2 for each pole screw nut 24.
6 can be made sufficiently smaller than the moving speed of the movable platen 18, each threaded portion 28 of the ball screw 26
．． 30 and the corresponding pole screw nuts 24, 32, the wear of the threaded portions of each ball screw mechanism can be effectively suppressed, and the service life thereof can therefore be greatly improved.

Next, another embodiment of the present invention will be described based on FIG. Note that this example differs from the previous example only in the configurations of the first and second rotary drive devices, so the following description will be made as follows.
Only the configurations of the first and second rotary drive devices will be described in detail.

That is, as shown in FIG. 2, in this embodiment, the movable plate 18 is positioned on the upper surface of the pressure receiving plate 12 and the bracket 70 fixed to the pressure receiving plate 12, and is spaced a predetermined distance in the moving direction of the movable plate 18. A pair of bearing members 72 are arranged so as to face each other apart from each other.
．． 73 is erected, and supported by these bearing members 72 and 73 so as to be rotatable and immovable in the axial direction, and a longitudinal cylindrical spline nut 74 is disposed.

A toothed pulley 40 is rotatably disposed on the outer peripheral surface of the spline nut 74, and as in the previous embodiment, the rotation of the toothed pulley 40 is transmitted to the second pole via the timing belt 42. The signal is transmitted to the screw nut 32.

Further, an electromagnetic clutch mechanism 76 is disposed between the toothed pulley 40 and the spline nut 74, and when the electromagnetic clutch mechanism '76 is connected, the toothed pulley 40 is connected to the spline nut 74, as will be described later. The rotational power transmitted to the nut 74 is transmitted to the timing belt 42.

Note that the electromagnetic clutch mechanism 76 here includes a coil 78
A multi-plate type is used in which a plurality of clutch plates 84 are compressed between the armature nearer 80 and the rotor 82 to perform a coupling operation by exciting the armature 80 and attracting the armature 80. It is also possible to adopt a type of electromagnetic clutch mechanism.

The spline nut 74 that transmits rotational power to the toothed pulley 40 has a spline formed at the end of its inner circumference on the movable platen 20 side. The motor shaft 88 of the servo motor 86 is
A spline shaft portion 90 at the tip thereof is fitted into the spline of the spline nut 74 .

In other words, the rotational power generated by the electric servo motor 86 mounted on the movable plate 20 is transmitted to the spline nut 74.
and the toothed boo 174 via the electromagnetic clutch mechanism 76.
0 and, in turn, to the second pole screw nut 32.

Note that, as shown in FIG. 2, the spline shaft portion 90 of the motor shaft 88 of the electric servo motor 86 has a sufficient length, so that the spline nut 74 can be attached to the spline nut 74 regardless of the moving position of the movable platen 2o. It is designed to be fitted at all times.

Furthermore, as is clear from the above description, in this example,
Electric servo motor 86. Spline nut 74. The electromagnetic clutch mechanism 76 and the like constitute a first rotational drive device.

On the other hand, the toothed boolean I760 that transmits rotational power to the ball screw 26 via the timing belt 62 is arranged so as to be directly rotatable with respect to the motor shaft 88 of the electric servo motor 86, as shown in the figure. An electromagnetic clutch mechanism 92, which is a multi-plate clutch mechanism similar to the electromagnetic clutch mechanism 76, is disposed between the motor shaft 88 and the toothed pulley 60. When this electromagnetic clutch mechanism 92 is connected, the rotational power generated by the electric servo motor 88 is transferred to the toothed pulley 60 via the electromagnetic clutch mechanism 92.
The signal is transmitted to the ball screw 26, and in turn is transmitted to the ball screw 26.

Note that the coil 78 of the electromagnetic clutch mechanism 92 is connected to the movable platen 2.
It is held by a bracket 94 whose position is fixed at 0. Further, as is clear from the above description, the electric servo motor 86 and the electromagnetic clutch mechanism 92 constitute a second rotational drive device.

If such configurations are adopted as the first and second rotation drive devices, the second pole screw nut 32 can be selectively connected to the first and second electromagnetic clutch mechanisms 76.92. and the ball screw 26 can be selectively driven to rotate. Therefore, similarly to the previous embodiment, the mold 1
It is possible to simultaneously secure the mold clamping force during mold clamping in steps 1 and 19 and increase the moving speed of the movable platen during mold opening/closing, and without generating large noises during high-speed mold opening/closing.

Further, if such a configuration is adopted as the first and second rotation drive devices, only one electric servo motor is required, which is economically advantageous.

Note that in this embodiment, the electric servo motor 86 is connected to the movable platen 2.
Although the electric servo motor 86 is installed on the 0 side, it is also possible to install the electric servo motor 86 on the pressure receiving plate 12 side. While the toothed pulley 60 of the moving plate 20 may be arranged to be rotatable directly about the shaft 88, it is also possible to arrange the toothed pulley 60 of the 20 movable plates to be rotatable indirectly about the motor shaft 88 via a spline nut (74). It is possible.

Furthermore, when structures such as those of this embodiment are adopted as the first and second rotary drive devices, the first and second clutch mechanisms 76 and 92 are used as the first and second brake mechanisms, respectively. It is also possible to do so.

Although a few embodiments of the present invention have been described above in detail, these are literal illustrations, and it goes without saying that the present invention should not be construed as being limited to these specific examples.

For example, in the embodiment described above, the ball screw 26 was screwed into the first pole screw nut 24 at its right-hand threaded portion 28 and into the second pole screw nut 32 at its left-hand threaded portion 30, but the ball screw 26 It is also possible to adopt a configuration in which the right-hand threaded portion 28 of the left-hand threaded portion 28 is threaded into the second pole screw nut 32, and the left-hand threaded portion 30 is threaded into the first pole screw nut 24, respectively.

Further, in the embodiment described above, both the first and second brake mechanisms are of the spring-close type, but it is also possible to use other types of brake mechanisms. However, when the present invention is applied to a vertical mold clamping device, for safety reasons, it is desirable to use a type that is set to a braking state when not energized, such as a spring-closed type.

Furthermore, in the embodiment, the movable plate 20 is disposed slidably with respect to the stay 14, and the second rotary driving bag rotates the ball screw 26. 1ii (58, 86) and a second brake mechanism (64) that prevents rotation of the ball screw 26.
was designed to be moved in the axial direction integrally with the movable plate 20, that is, with the ball screw 26, but the second rotary drive device and the second brake mechanism are not necessarily integral with the ball screw. For example, in the embodiment described above, while the movable platen 20 is fixed to the base 16, the actuating sleeve 52 is spline-fitted to the ball screw 26. It is also good.

In addition, although it is omitted to list specific examples one by one, the present invention can be carried out in various forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art without departing from the spirit thereof. It goes without saying that it can be done.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view showing an example of a mold clamping device according to the present invention, and FIG. 2 is a partially cutaway sectional view showing a main part of another embodiment of the present invention. 10: Fixed plate 12: Pressure receiving plate (stationary member) 18:
Movable plate 20: Movable plate 24: Pole screw nut (first nut member) 26: Ball screw 28: Right threaded portion 30: Left threaded portion 32: Second pole screw nut 34.52: Operating sleeve 38: Electric servo motor (First rotational drive device) 44:
Electromagnetic brake mechanism (first brake mechanism) 58: Electric servo motor (second rotation drive device) 64: Electromagnetic brake mechanism (second brake mechanism) 74 Nispline nut 76.92: Electromagnetic clutch mechanism 86: Electric servo motor

Claims (1)

[Scope of Claims] Comprising a fixed platen and a movable platen that can approach and move away from the fixed platen, the movement of the movable platen toward and away from the fixed platen causes the movable platen and the fixed platen to move. A mold clamping device for an injection molding machine configured to clamp a mold between a first nut member disposed at a fixed position relative to the movable platen, and a first nut member disposed at a fixed position relative to the fixed platen. a second nut member rotatably supported by a fixed stationary member; a right-handed threaded portion and a left-handed threaded portion; A ball screw member screwed into the first nut member with a predetermined ball screw structure, a first rotational drive device that rotationally drives the second nut member, and a rotation drive device that forces the rotation of the second nut member. A second brake mechanism that rotationally drives the ball screw member; and a second brake mechanism that forcibly blocks rotation of the ball screw member. Mold clamping device for injection molding machines.