JPH10291239A - Mold clamping device for motorized vertical type injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure and save power. SOLUTION: In a mold clamping device for a motorized vertical type injection molding machine, when a power source of a motor 27 is turned on in the mold opening state, a platen 27a stopping the free rotation of the motor 27 is put off, and the motor 27 is actuated to rotate a screw shaft 22 and lower a nut component 21 together with a cross head 20, by which a toggle mechanism 11 is stretched to lower an end plate 5 and also lower a movable platen 3 and carry out the mold clamping. The mold opening is carried out by counter rotating the screw shaft 22 and the movable plate 3 is lifted. When the mold opening is completed, the motor 27 is stopped and the platen 27a is actuated to damp the free rotation of the motor 27 and prevent the natural lowering of the movable platen 3. The motor 27 and a transmission mechanism 30 can be stopped on the given positions to simplify the structure. As power is not consumed during the operation of the platen 27a, the power-saving is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vertical injection molding machine, and more particularly to a mold clamping device for moving a movable platen relative to a fixed platen.

[0002]

2. Description of the Related Art As a mold clamping device of an electric vertical injection molding machine,
The one shown in FIG. 5 has been proposed (JP-A-5-2008)
No. 13). To explain this, the movable platen 3 is provided above the fixed platen 2 fixed to the machine body 1 with a tie bar 4.
The end plate 5 is fixed to the lower end of the tie bar 4 and fixed to the lower end of the tie bar 4 so as to move up and down with respect to the fixed platen 2 together with the movable platen 3. I have.

[0003] The fixed platen 2 and the end plate 5
A pair of toggle links 41, 42 are pivoted 43, 44, respectively.
Is mounted so that it can be turned up and down freely.
5 are connected to each other so as to be able to flex vertically. The toggle links 42, 42 have a bell crank shape and have nut members 46a, 46b at the lower ends. Nut member 46
a and 46b are mutually reverse-threaded, and are screwed to the mutually reversely-threaded screw portions 47a and 47b of the horizontal screw shaft 47, respectively.

The screw shaft 47 is rotatable in the circumferential direction, and is connected to an electric motor 48 via a required transmission mechanism 49. The screw shaft 47 is supported vertically by a transmission mechanism 49, and an electric motor 48 is provided on a guide table 50 so as to be movable in a direction perpendicular to the plane of FIG. Dies 7 and 8 are attached to the fixed platen 2 and the movable platen 3. Reference numeral 9 denotes an injection device.

In the above-described mold clamping device of the electric vertical injection molding machine, when the screw shaft 47 is rotated by the operation of the electric motor 48 to move the nut members 46a and 46b away from each other, the toggle links 41 and 42 become Since the end plate 5 is lowered by being extended linearly, the movable platen 3 is clamped and moved downward, and the molds 7 and 8 are clamped between the movable platen 3 and the fixed platen 2. At this time, the screw shaft 47 descends with the rotation of the toggle links 42, 42, and the electric motor 48 moves on the guide table 50 as the screw shaft 47 descends.

[0006]

The above-described mold clamping device for an electric vertical injection molding machine can eliminate the unbalanced load that occurs when the electric motor 48 is directly connected to one end of the screw shaft 47 and can be freely moved up and down. Since the transmission mechanism 49 and the like must be moved following the vertical movement of the screw shaft 47, the structure becomes complicated. Further, since it is structurally difficult to increase the rotation angle of the bell crank-shaped toggle link 42, there is also a complaint that the opening and closing stroke of the movable platen 3 cannot be increased.

The present invention provides a mold clamping device for an electric vertical injection molding machine, which has a simple structure, can save power, and can automatically prevent the movable plate from naturally descending during a power failure. The purpose is to do. Another object of the present invention is to provide a mold clamping device for an electric vertical injection molding machine that can increase the opening and closing stroke of a movable plate.

[0008]

In order to achieve at least one of the above objects, according to the present invention, a movable plate is fixed to an upper end of a tie bar above a fixed plate fixed to a machine body. In the vertical injection molding machine, an end plate is fixed to a lower end of the tie bar and provided vertically with respect to the fixed plate together with the movable plate below the fixed plate. In the plate portion, a screw mechanism for moving the end plate up and down together with the movable plate by vertical movement of the nut member screwed to the screw shaft along the screw axis is provided, and the screw shaft of the screw mechanism includes:
An electric motor that rotates the screw shaft to move the nut member up and down is connected, and the electric motor is provided with a brake that operates when power is turned off to brake the free rotation of the electric motor.

In the above means, when the motor is driven, the nut member of the screw mechanism moves up or down along the screw shaft in accordance with the rotation direction of the motor, and moves the end plate up and down together with the movable plate. . When the power is turned off due to a stop of the motor or a power failure, a brake is automatically operated to apply a brake to the free rotation of the motor.

[0010] In the above-described mold clamping device of the electric vertical injection molding machine, it is preferable that the screw mechanism has a ball screw structure or a roller screw structure (claim 7).
The movable platen can be opened and closed smoothly.

In the above-mentioned mold clamping device, a toggle link, which is connected to a fixed plate and an end plate by a toggle pin so as to be able to bend up and down freely by a toggle pin, is connected to a top and a bottom of a crosshead connected to the toggle link by a toggle piece. A toggle mechanism for extending the movable platen by clamping in a direction and moving the movable platen with the mold may be configured such that the crosshead is connected to a nut member. According to this means, the boosting function of the toggle mechanism can be utilized.

The toggle link of the toggle mechanism may be configured to extend by moving the toggle pin closer to the screw shaft (claim 3), and the toggle link may be configured to extend by moving the toggle pin away from the screw shaft. (Claim 4).

[0013] Further, the toggle piece of the toggle mechanism may be connected to a free end opposite to the toggle pin of a toggle link pivotally connected to the end plate by a connecting pin (claim 5). Alternatively, a configuration may be employed in which a toggle pin is connected to an intermediate portion of a toggle link that is pivotally attached to the fixed platen side by a coupling pin (claim 6). It is also possible to adopt a structure that does not use a toggle mechanism.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
In addition, the fixed platen 2, the movable platen 3, the end plate 5, etc.
Since the basic configuration of the main part of the vertical injection molding machine is the same as that of FIG. 5, the same reference numerals are given and the detailed description is omitted.
In FIG. 1, the left half shows the mold open state, and the right half shows the mold clamped state. This point is the same in other FIGS. 2 to 4.

In FIG. 1, reference numeral 11 denotes a toggle mechanism. The toggle mechanism 11 is attached to the lower surface of the fixed platen 2 so as to be vertically rotatable about a pivot 12, and is attached to the upper surface of the end plate 5 so as to be vertically rotatable about a pivot 14. Toggle pin 1 on toggle link 13
The toggle links 16, 16 connected by 5 and the mounting shaft 17
And a crosshead 20 connected to the other end of the toggle link 16 by a connecting pin 19. Left and right two sets of toggle links 13, 1
6 can bend up and down. The pivot 14 of the end plate 5 is provided directly below the pivot 12 of the fixed platen 2.

Reference numeral 22 denotes a screw shaft. Screw shaft 22
Is in the middle of the two sets of toggle links 13 and 16,
The upper end and the lower end are pivotally supported by the fixed platen 2 and the bearings 23 and 24 of the machine body 1, and are vertically provided so as to be rotatable in the circumferential direction in a state where the movement in the axial direction is stopped. A nut member 21 is screwed to the screw shaft 22 to form a screw mechanism 31. The nut member 21 is integrally connected to the crosshead 20. The screw mechanism 31 preferably has a ball screw structure or a roller screw structure.

The crosshead 20 is guided by a plurality of guide rods 25 (only one is shown in FIG. 1) which is vertically fixed to the fixed board 2 or the machine body 1.
Therefore, when the screw shaft 22 is rotated, the nut member 21 is rotated.
Thereby, the crosshead 20 is moved up and down along the guide rod 25.

A driven pulley 26 is attached to the lower end of the screw shaft 22, and is connected to a driving pulley 28 of an electric motor 27 such as a servomotor by a timing belt 29. The pulleys 26 and 28 and the belt 29 control the rotation of the electric motor 27 with the screw shaft 2.
Although the transmission mechanism 30 for transmitting the power to the transmission mechanism 2 is configured, the transmission mechanism 30 may use another transmission member such as a gear. The electric motor 27 is fixed to the machine body 1,
A brake 27a is provided. The brake 27a is configured to operate when the power is turned off to brake the free rotation of the electric motor 27.

The mounting positions of the pulley 26 and the electric motor 27 are not limited to those shown in FIG.
The motor 27 can be fixed near the fixed platen 2 or to the fixed platen 2 in accordance with the second embodiment shown in FIG.

Although only one tie bar 4 is shown in FIG. 1, two or more (normally four) tie bars 4 are provided. Taiba 4
The lower end of is screwed into an adjustment nut 32, and by rotating the adjustment nut 32, the distance between the movable platen 3 and the end plate 5 can be finely adjusted according to the thickness of the molds 7, 8. It has become.

Next, the operation of the above-configured mold clamping device for the electric vertical injection molding machine according to the present invention will be described. When the power of the electric motor 27 is turned on from the mold open state on the left side of FIG. 1, the brake 27a which has stopped the free rotation of the electric motor 27 until then.
Is turned off and the electric motor 27 operates to rotate the screw shaft 22 and lower the nut member 21 together with the crosshead 20, so that the inner end of the toggle link 16 is
As a result, the toggle link 16, 13 is pivoted inward about the pivots 14, 12 to lower the end plate 5 so that the toggle pin 15 approaches the screw shaft 22. As a result, the movable platen 3 moves downward in the mold clamping together with the end plate 5, and when the toggle links 13 and 16 extend linearly as shown in the right side of FIG. 1, the electric motor 27 is stopped to complete the mold clamping. in this case,
The brake 27a operates to brake the free rotation of the electric motor 27. The operation of the second embodiment shown in FIG. 2 is the same as that of FIG.

In the mold clamping completed state on the right side of FIG. 1, the power is turned on, the electric motor 27 is operated (the brake 27a is turned off), and the screw shaft 22 is rotated in the reverse direction. Since the end plate 5 is bent and lifted, the movable platen 3 opens upward and moves. When the power is turned off and the drive of the electric motor 27 is stopped to complete the mold opening,
Immediately, the brake 27a is operated to stop the free rotation of the electric motor 27.

In the above-mentioned toggle type mold clamping device, when the movable platen 3 is opened and closed by the operation of the toggle mechanism 11, there is no need to move the transmission mechanism 30 or the electric motor 27, so that the structure is simplified. Therefore, it is possible to manufacture a highly reliable mold clamping device which is less likely to break down and is inexpensive.
In addition, since there is almost no structural restriction on the rotation angle of the toggle link 16, it can be increased to increase the opening / closing stroke of the movable platen 3. Also, the brake 27a
Is configured to operate when the power is turned off to apply a brake to the free rotation of the electric motor 27, so that the automatic operation is performed even if there is an unexpected power failure, and the natural fall of the movable platen 3 is prevented. . Moreover, since the brake 27a does not consume power during braking, power consumption can be reduced.

FIG. 3 shows a third embodiment of the present invention.
In the case of this mold clamping device, the toggle piece 18 is connected to the connecting pin 1.
The toggle links 13 and 16 which are connected to the intermediate portion of the toggle link 13 at 9 and which are bent inward by bringing the toggle pin 15 close to the screw shaft 22, connect the toggle pin 15 to the screw shaft 2.
2 so as to be separated from the second and extend linearly. The pivot 14 of the end plate 5 is provided at a position directly below the pivot 12 of the fixed platen 2 or at a position slightly inward from the position directly below. Other structures and operations are the same as those of the mold clamping device of FIG.

FIG. 4 shows a fourth embodiment of the present invention.
In the case of this mold clamping device, the crosshead 20 is disposed below the end plate 5. Other structures and operations are the same as those of the apparatus of FIG. 1, but the height can be reduced in this mold clamping apparatus.

Each of the mold clamping devices shown in FIGS.
Although the crosshead 20 is configured to descend and clamp the mold, the crosshead 20 may be elevated and clamped. Either or both of the toggle links 13 and 16 may have a configuration in which two or more link units are pin-connected.

[0027]

As described above, according to the first aspect of the present invention, the movable plate is fixedly provided on the upper end of the tie bar above the fixed plate fixed to the machine body, and the movable platen is provided below the fixed plate. In a vertical injection molding machine in which an end plate is fixed to the lower end of the tie bar and is vertically movable with respect to the fixed plate together with the movable plate, a screw shaft is screwed to the end plate portion. A screw mechanism for moving the end plate up and down together with the movable plate by vertical movement of the nut member along the screw shaft is provided, and the screw shaft of the screw mechanism is rotated by rotating the screw shaft to remove the nut member. Since the motor that moves up and down is connected, and the motor and the transmission mechanism do not need to be movable structures, the structure is simplified. Therefore, it is possible to manufacture a highly reliable mold clamping device which is less likely to break down and is inexpensive. In addition, the motor is equipped with a brake that operates when the power is turned off and brakes the free rotation of the motor, so that power can be saved, and unlike the servo lock when the motor is a servo motor, the motor is damaged. Can be prevented. In addition, it is possible to prevent the movable board from lowering naturally during a power failure.

A toggle link, which is connected between the fixed plate and the end plate by a toggle pin so as to be able to bend up and down freely by a toggle pin, is extended and moved by a vertical movement of a crosshead connected to the toggle link by a toggle piece. In the case where the toggle mechanism for clamping and moving the board is configured such that the crosshead is connected to the nut member, there is almost no restriction on the rotation angle of the toggle link in terms of structure, and therefore, the rotation of the toggle link is restricted. By increasing the moving angle, the opening and closing stroke of the movable plate is increased, and the workability of the mold clamping device can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a mold clamping device of an electric vertical injection molding machine according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a front view of a mold clamping device of a conventional electric vertical injection molding machine.

[Explanation of symbols]

Reference Signs List 1 machine body 2 fixed plate 3 movable plate 4 tie bar 5 end plate 11 toggle mechanism 12, 14 pivot 13, 16 toggle link 15 toggle pin 18 toggle piece 19 connection pin 20 crosshead 21 nut member 22 screw shaft 27 electric motor 27a brake 30 transmission mechanism 31 Screw mechanism

Claims (7)

[Claims] A movable plate fixed to an upper end of a tie bar provided above a fixed plate fixed to a machine body; and an end plate fixed to a lower end of the tie bar below the fixed plate. In a vertical injection molding machine provided vertically with respect to the fixed plate together with a movable plate, the nut member screwed to a screw shaft is vertically moved along the screw shaft on the end plate. A screw mechanism for moving the end plate up and down together with the movable plate is provided, and a motor for rotating the screw shaft to move the nut member up and down is connected to a screw shaft of the screw mechanism. A mold clamping device for an electric vertical injection molding machine, further comprising a brake which is activated when the motor is cut off to brake the free rotation of the electric motor. 2. A toggle link, which is connected between a fixed plate and an end plate by a toggle pin so as to be able to bend and extend vertically by a toggle pin, is extended by a vertical movement of a crosshead connected to the toggle link by a toggle piece. 2. A mold clamping device for an electric vertical injection molding machine according to claim 1, wherein a toggle mechanism for clamping and moving the movable platen is provided by connecting said crosshead to a nut member. 3. The mold clamping device for an electric vertical injection molding machine according to claim 2, wherein the toggle link is configured to extend by moving the toggle pin closer to the screw shaft. 4. The mold clamping device for an electric vertical injection molding machine according to claim 2, wherein the toggle link is configured to extend by moving the toggle pin away from the screw shaft. 5. The toggle piece according to claim 2, wherein the toggle piece is connected to the end plate by a connecting pin at a free end opposite to the toggle pin of the toggle link pivotally connected to the end plate. Mold clamping device for electric vertical injection molding machine. 6. The electric vertical type according to claim 2, wherein the toggle piece is connected to a middle portion of a toggle link pivotally connected to the fixed plate by a connecting pin. Mold clamping device for injection molding machines. 7. The mold clamping device for an electric vertical injection molding machine according to claim 1, wherein the screw mechanism has a ball screw structure or a roller screw structure.