JPH05200814A - Driving device for mold clamping - Google Patents

Abstract

PURPOSE:To make a movable part lighter and prevent a mold clamping mechanism from receiving eccentric load so as to improve the parallelism between an upper and a lower molds by a method wherein the driving motor of the toggle type mold clamping mechanism of a vertical injection molder is shifted to its fixed part. CONSTITUTION:A driving motor 16 is vertically fixed through a bracket 15 to the bottom plate 1a of a bed. Further, a spline shaft 17 is vertically provided near tire driving motor so as to rotate the spline shaft by gears 18 and 19. Furthermore, a ball screw 14 is rotated through a bevel gear 22, which engages with the spline shaft, and a bevel gear 23 provided at the tip of the ball screw 14 in order to bend toggle arms for opening and closing mold and allow to transmit torque at all times to the ball screw, which moves vertically together with its rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a toggle type mold clamping mechanism of a vertical injection molding machine.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a toggle type mold clamping mechanism of a vertical injection molding machine is provided with a rotatable connecting portion in the middle so that both ends of two refractable links 101 can be bent. , A fixed platen 102 and a rear platen 103 are rotatably connected to each other to form a toggle mechanism, and a nut 107 is fixed to one side and a motor 107 having a ball screw directly connected to an output shaft is fixed between the two connecting parts of the link. A driving device has been used in which a screw mechanism is provided to change the distance between both connecting portions to open and close the die 105 fixed to the lower surface of the upper platen 104 and the upper surface of the fixed platen 102.

[0003]

In the drive device of the toggle type mold clamping mechanism of the prior art, the motor is fixed in an unbalanced state to the movable part that moves up and down at the same time when the upper platen and the rear platen vertically move up and down. Therefore, the weight in the movable part and the unbalanced load due to the mounting position of the heavy object adversely affect, and there is a problem that the mold opening and closing cannot be performed while maintaining the parallelism of the mold mounting surfaces of the fixed platen and the upper platen, Further, since the weight of the movable portion becomes large, it takes time to accelerate and decelerate the motor, which makes it difficult to open and close the mold at high speed. The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a mold clamping mechanism by moving a drive motor from a movable part of the mold clamping mechanism to another place. It is an object of the present invention to provide a drive device capable of reducing the size and weight of a movable part while preventing an unbalanced load from being applied.

[0004]

In order to achieve the above object, a mold clamping drive device according to the present invention is a mold clamping mechanism for closing a mold fixed to a lower surface of an upper platen and an upper surface of a fixed platen by pushing down a rear platen. In the drive,
The lower end of a rotatable toggle link whose upper end is pivotally supported by the fixed platen and the upper end of a toggle arm whose central part is pivotally supported by the rear platen and bent to the opposite side of the toggle are the fixed platen. A symmetrical left-right toggle mechanism that pivots in the center of the rear platen to allow bending is provided, and a right-hand thread nut and a left-hand thread nut of the same pitch pivotally supported at the lower end of the toggle arm respectively with right-hand thread A screw that is concentric and integral with the left screw is horizontally screwed, and a spline shaft that is rotated by a drive motor that is fixed to the fixed portion is provided at a right angle and perpendicular to the screw, and the spline shaft can move in the axial direction. And a gear member that is engaged with the screw and transmits the rotational force to the screw.

[0005]

[Operation] When the spline shaft is rotated by the drive motor and the screw is rotated through the bevel gear, the toggle mechanism bends and the rear platen and upper platen connected by the tie bar move vertically up and down to open and close the mold. It During the bending vibration of the toggle mechanism, the screw moves up and down together with the air platen, but the rotational force is always transmitted to the screw by the spline shaft.

[0006]

EXAMPLE A first example will be described with reference to FIGS. A fixed platen 2 is horizontally fixed to an upper surface of a bed 1 installed on the floor, and four tie bars 3 are inserted into vertical holes formed in the bed 1 and the fixed platen 2 so as to be axially movable. An upper platen 4 is horizontally fixed to the upper end of the. The plasticizing unit 5 is attached downward on the upper platen 4, the rear platen 6 is horizontally fixed to the lower end of the tie bar 3, and the molds 10A and 10B are attached to the lower surface of the upper platen 4 and the upper surface of the fixed platen 2. Has been.

Two toggle links 7A and 7B are rotatably and symmetrically rotatably supported at their upper ends by a pin 8 at positions apart from the center of the lower surface of the fixed platen 2, and are toggled at symmetrical positions on the upper surface of the rear platen 6. On the other hand, toggle arms 9A and 9B bent to the opposite side are rotatably and symmetrically supported by a pin 11 at the intersection of the arm upper side 9a and the arm lower side 9b. The toggle links 7A and 7B and the arm upper side 9a of the toggle arms 9A and 9B have the same length, and the arm lower side 9b of the toggle arms 9A and 9B is formed longer than the arm upper side 9a. , 7
The lower end of B and the upper ends of the toggle arms 9A and 9B are rotatably connected by a connecting pin 12 at the center of the fixed platen 2 and the rear platen 6 to form a bendable toggle mechanism. Furthermore, a left lead left screw nut 13A is provided at the lower end portion of the toggle arm 9A, and a right lead right screw nut 13B is provided at the lower end portion of the toggle arm 9B so as to be swingable so that the axial direction can always maintain a horizontal posture. The left-hand thread nut 13A and the right-hand thread nut 1 are supported.
A ball screw 14 in which a left screw and a right screw are integrally formed is horizontally screwed to 3B.

On the other hand, a drive motor 16 is vertically and downwardly fixed to the bottom plate 1a of the bed 1 via a bracket 15, and a spline shaft 17 is rotatably supported near the drive motor 16. A gear 18 is fitted on the output shaft of the drive motor 16, and the gear 18 is meshed with a gear 19 fitted on the spline shaft. The gear case 21 rotatably provided at the end of the ball screw 14
A bevel gear 22 in which a sleeve 24 having a spline groove engaged with the spline shaft 17 formed in a central hole is fitted is rotatably supported in the gear case 21.
The bevel gear 23 fitted inside the ball screw 14 is meshed with the bevel gear 22 inside the gear case 21. The gear case 21 is formed of a material such as an aluminum casting having a small specific gravity so that an unbalanced load applied to the tip of the ball screw 14 is reduced.

Next, the operation of the embodiment will be described. When the spline shaft 17 is rotated by the drive motor 16 via the gears 18 and 19 and the ball screw 14 is rotated to the right via the bevel gears 22 and 23 (as viewed from the gear side), the nuts 13A and 13B face each other outward. To open the distance, the upper end connecting portions of the toggle arms 9A and 9B are swung inward in the inward winding direction around the pin 11, the distance between the connecting pins 12 is reduced, and the toggle links 7A and 7B and the toggle arms 9A and 9A, The bending angle α _{1 of} 9B gradually increases, the rear platen is pushed down by the downward force F0, the upper platen 4 descends via the tie bar 3, the mold clamping process ends, and the state shown in FIG. 3 is reached. The axis of the screw 14 is at the lower limit position a.

Next, when the injection process is completed, the drive motor 1
The ball screw 14 is rotated counterclockwise by 6 and the nut 13A,
13B move inward toward each other to reduce the distance, and the upper end connecting portions of the toggle arms 9A and 9B are swung in the outer winding direction to the states shown in FIGS. 4 to 7, and the molds 10A and 10B are opened. In the process of opening the mold, the ball screw 14 gradually moves upward while keeping horizontal and rises to the upper limit position b, and accordingly, the bevel gear 2 that engages with the spline shaft 17.
2 and a gear case 21 containing a bevel gear 23 that meshes with the gear 2 rises to constantly transmit a rotational force.

In the process of opening the mold, the upper spline 4
Since the plasticizing unit 5 is placed on the top, it is heavy and requires a large force, and the bending angle α ₁ at the start of mold opening in FIG.
Is equal to the force F1 when the bending angle α _{2 in} FIG. 5 is small, the ball screw 1
Thrust F1 of 4 gradually requires a large force. Therefore, the capacity of the drive motor 16 is set on the basis of this maximum thrust f1, but the drive motor 16 is fixed on the bottom plate 1a of the bed via the bracket 15, so that the influence on the mold clamping mechanism is restricted. It is possible to use a relatively large motor that has a margin. In this embodiment, the drive motor 16 is installed parallel to the spline shaft 17, but the drive motor is installed concentrically with the spline shaft 17 so that the rotational force is transmitted via the coupling. You can also

[0012]

Since the present invention is configured as described above, it has the following effects. Since the drive motor of the mold clamping mechanism that vertically moves up and down to open and close the mold is fixed to the fixed part and the screw is rotated via the spline shaft that is provided at right angles to and perpendicular to the screw, The adverse effect of the inertial force exerted by the own weight of the drive motor provided in the movable part of the conventional mold clamping mechanism can be eliminated, and the deflection due to an unbalanced load can be prevented, so that the parallelism of the upper platen with respect to the fixed platen is improved. In addition, by placing the drive motor separately, it is easy to secure a space for storing the motor, the weight of the mold clamping mechanism can be reduced, and the mold opening and closing speed can be increased. Since it can be installed, maintenance work is easy.

[Brief description of drawings]

FIG. 1 is a sectional view of a vertical injection molding machine having a spline shaft type mold clamping drive device of the present embodiment.

FIG. 2 is a side view of a spline shaft type mold clamping drive device.

FIG. 3 is an operation diagram for explaining the operation of the present embodiment.

FIG. 4 is an operation diagram for explaining the operation of the present embodiment.

FIG. 5 is an operation diagram for explaining the operation of the present embodiment.

FIG. 6 is a sectional view of a vertical injection molding machine having a conventional mold clamping drive device.

[Explanation of symbols]

2 Fixed platen 3 Tie bar 4 Upper platen 6 Rear platen 7A, 7B Toggle link 9A, 9B
Toggle arm 10A, 10B Mold 16 Drive motor 17 Spline shaft 18, 19
Gear 21 Gear case 22, 23
Bevel gear

Claims (1)

[Claims] 1. A drive device of a mold clamping mechanism for closing a mold fixed to a lower surface of an upper platen and an upper surface of a fixed platen by pushing down a rear platen, and a rotatable toggle having an upper end pivotally supported by the fixed platen. A bilaterally symmetric toggle in which the lower end and the center of the link are pivotally supported by the rear platen and the upper end of a toggle arm bent to the opposite side with respect to the toggle is pivotally connected at the center of the fixed platen and the rear platen to allow bending. A mechanism is provided, and right and left screw nuts of the same pitch, which are pivotally supported at the lower end of the toggle arm, are pivotally supported, respectively, and screws having concentric and integrated right and left screws are horizontally screwed. A spline shaft, which is rotated by a drive motor fixed to the fixed portion, is provided at a right angle and perpendicular to the screw and is engaged with the spline shaft so as to be movable in the axial direction A mold clamping drive device characterized in that a gear member for transmitting a rotational force is provided on the screw.