JPH0327911A - Clamping device - Google Patents

Abstract

PURPOSE:To speed up claming and mold opening and increase efficiency by combining toggle mechanisms and a crank mechanism. CONSTITUTION:Toggle mechanisms 8, 8' are provided with first links 10, 10' with one ends connected pivotally on the side of a rear platen 4 and second links 11, 11' with one ends pivotally with a moable platen 5, and the open end sides of said links are connected pivotally with connecting blocks 12, 12' respectively. A crank mechanism 9 is a two-arm type mechanism consisting of first arms 14, 14' fixed on a driving shaft 13 and second arms 15, 15' connected pivotally on the open end sides of the first arms and the other end sides of the second arms 15, 15', that is, the movable side of the crank mechanism 9, are connected pivotally with connecting blocks 12, 12'. Thus, the toggle mechanisms 8, 8' and the crank mechanism 9 are connected with each other by means of connecting blocks 12, 12'. Clamping and mold opening are speeded up by said arrangement to increase the efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a three-platen mold clamping device for an injection molding machine or the like.

Prior Art 3 In platen type mold clamping devices, there are direct pressure type, toggle type, and crank type as drive mechanisms for the movable platen, and each type includes hydraulic type and electric motor type.

Among these, toggle-type mold clamping devices driven by electric motors usually use a ball screw/nut mechanism to convert the rotational motion of the motor into linear motion.

However, with this mechanism, a device with a large mold clamping force requires a large diameter ball screw or a motor with a large output torque, and as a result, the mold clamping device tends to be expensive.

In addition, the characteristic of such a mechanism that the nut moves at a constant speed with respect to the ball screw is that it moves quickly until just before it touches the mold, and moves slowly in the area from near the mold touch to lockup. In some cases, this did not necessarily match the operating characteristics of the mold clamping device, which is said to be preferable.

Problems to be Solved by the Invention It is an object of the present invention to provide a mold clamping device that can exert sufficient mold clamping force using an electric motor with a normal output, and can quickly perform mold clamping and mold opening operations.

Means for Solving the Problems [First Invention] In a three-plate mold clamping device, a rear platen and a movable platen are connected by a toggle mechanism having a bending point in the middle.

A bearing plate is provided between the rear platen and the movable platen so as to be movable in parallel to the mold clamping axis, and a vertical guide portion is provided on the bearing plate in a direction perpendicular to the mold clamping axis.

In the maximum extension state of the toggle mechanism, the drive shaft of the crank mechanism is pivotally supported at the fixed position of the bearing plate at the position where the crank is in the extension state, on a line passing through the bending point and perpendicular to the mold clamping axis.

The crank mechanism has a first arm and a second arm, one end of the first arm is fixed to the drive shaft, the other end of the second arm is a movable end of the crank mechanism, and the movable end is the bending end of the toggle mechanism. It is rotatably connected to the vertical guide part of the bearing plate along with the point.

[Second invention] The drive shaft of the crank described above is interlocked and connected to a servo motor.

The action toggle mechanism and crank mechanism convert the output of the motor into mold clamping force and move the movable platen to the lock-up position and the mold-opening position.

Embodiment FIG. 2 schematically shows the entire injection molding machine 1, in which an injection device 2 and a mold clamping device 3 are arranged facing each other.

The mold clamping device 3 is a three-plate type and includes a rear platen 4, a movable platen 5, and a front platen 6 from the rear (left side of the figure).The rear platen 4 and the front platen 6 are connected by a tie rod 7 parallel to the mold clamping axis a. tie rod 7
The above-mentioned movable platen 5 is attached so as to be slidable in the front-rear direction.

Note that the mold clamping axis a coincides with the line of action of the total mold clamping force.

Toggle mechanisms 8 and 8' are disposed above and below between the rear platen 4 and the movable platen 5, and both ends of each are connected to the platens 4 and 5 to form a double toggle mechanism 19. This double toggle mechanism 19 is connected to and driven by the crank mechanism 9.

The toggle mechanism 8.8' includes a first link 10.1 whose one end is rotatably connected to the rear platen 4 side, as shown in FIG.
0- and the second movable platen 5, one end of which is rotatably connected to the movable platen 5.
It is provided with links 11.11-, each of which has its free end side connected to a connecting piece 12.12- in a freely movable manner.

The crank mechanism 9 is a first arm 1 fixed to a drive shaft 13.
4.14- (Fig. 3) A two-arm mechanism consisting of a second arm 15.15- rotatably connected to the free end side of the second arm 15.15', the other end side of the second arm 15.15'; That is, the movable end of the crank mechanism 9 is rotatably connected to the connecting pieces 12, 12-. The two movable ends of the crank mechanism 9 are vertically symmetrical.

The connecting piece 12.12 connects the toggle mechanism 8, 8' and the crank mechanism 9, and also constitutes a bending point of the toggle mechanism 8.8'.

The drive shaft 13 of the crank mechanism 9 is pivotally supported by bearing plates 20 disposed on both sides of the mold clamping device 3, and is connected via a servo motor 18 disposed on one bearing plate 20, a pulley 16, and a timing belt 17. Linked together.

The bearing plates 20 are guided by two slide rods 21 that are provided between the rear platen 4 and the movable platen 5 in parallel with the mold clamping axis a, and the bearing plates 2 on both sides
0.20 is connected by a pair of front and rear horizontal plates 2,22.

Reference numeral 24 denotes a support of the slide rod 21, which is erected and fixed on both sides between the rear platen 4 and the movable platen 5.

Furthermore, a guide rod 23 is fixed to each of the horizontal frames 22 so as to protrude in the vertical direction, and the connecting piece 12.12'' is slidably attached to this.

The toggle mechanisms 8, 8' and the crank mechanism 9 are arranged as shown in FIG. In addition, in Fig. 3, the upper half is the crank mechanism 9.
The lower half shows the position in which the first arm 14.14- of FIG. The following explanation will be given only regarding the first half. Further, normally, the arm 14 and the arm 14' are configured as one linear arm.

That is, the connection points between both ends of the toggle mechanism 9 and the rear platen 4 and the movable platen 5 are A and B, the bending point is C1, and the drive shaft of the crank mechanism 9 is D1.
0 and the second arm 11 is E1, and the movable end of the crank 9 coincides with the bending point C, then the crank mechanism 9
When the drive shaft D of is in the maximum extension state of the toggle mechanism 8 (
A, B, and C are lined up almost in a straight line), and the first and second arms 14.15 are in an extended state (C, E, D
(becomes a substantially straight line) is pivotally supported at a fixed position on the bearing plate 20.

As a result, the bending points of the toggle mechanisms 8, 8' and the drive shaft 13 of the crank mechanism 9 are always on a line perpendicular to the same mold clamping axis a when viewed from the bearing plate 20, and the crank mechanism 9
When the toggle mechanism 8.8' is actuated and the toggle mechanism 8.8' is bent and extended, the drive shaft 13 moves back and forth together with the bearing plate 20.

The operation of the above structure will be explained based on FIG.

When the mold clamping device 3 is in the lock-up position, the drive shaft 13 of the crank mechanism 9 is rotated between A and C as shown by the solid line in FIG.
, B are almost straight lines, and the angles exerted by the first and second arms of the crank mechanism 9 are also almost straight.

From this state, when the servo motor 18 is driven in the mold opening direction by the control device of the injection molding machine, the first arm 4 of the crank mechanism 9 is rotated to the left, and the E point changes to the E1 point, and , point C reaches point Cl. At this time, the movement of point C is guided by the guide rod 23 and is always perpendicular to the mold clamping axis a. Furthermore, in order to allow this vertical movement, the drive shaft 13 itself moves backward (to the left) together with the bearing plate 20. Moving.

That is, in FIG. 3, when the first arm of the crank mechanism 9 rotates 90 degrees, point B, which means the movable platen 5, moves to point 81, which is the mold opening position. The distance between B and Bl is actually the point A, which means the rear platen 4, which does not move (AB-A''BI), and this is the stroke of the mold clamping device 3'.

This operation has the following characteristics.In the mold opening operation, the toggle mechanism 8, each link of the crank mechanism 9, and the arm gradually increase the inclination angle from the maximum extension state. The moving speed of the movable platen 5 is small at a stage where careful operation is required, and increases rapidly thereafter.

In the mold clamping operation, conversely to the above, the movable platen 5 moves at a high speed until just before the mold is touched, and the mold touching and lockup are performed at a low speed.

Furthermore, since the angles formed by each link and each arm of the toggle mechanism 8 and crank mechanism 9 are close to straight lines after the mold is touched and until the mouth is checked up, the output of the servo motor is converted into a large mold clamping force. , the mold clamping force is sufficient to extend the tie rod.

Since the drive shaft 13 can move in the front-rear direction together with the bearing plate 20, the movement of the crank mechanism 9 itself and the bending of the toggle mechanism 8 work to be expanded simultaneously with the rotation of the first arm 14.
The stroke of the movable platen 5 can be made very large.

Since the movable end of the crank mechanism 9 (the bending point of the toggle mechanism 8) always moves along an axis perpendicular to the mold clamping axis a by using the guide rod 23 as the drive shaft 13 moves back and forth, the crank mechanism 9 The first for the upper half and the lower half
It is possible to attach the arms 14, 14- to the drive shaft 13 in the form of one continuous arm. This allows one servo motor 18 to drive the double toggle mechanism 19 connected to the crank mechanism without any problem.

Note that the length of each link and arm is determined as follows as one method. That is, usually from the design point of view, the above C
, D and the lengths of the movement strokes B and Bl required for the movable platen 5 are determined, so first,
CE and ED are determined by allocating the dimensions between C and D so that the second arm l5 is longer than the first arm 14, and then, in conjunction with the rotation angle set for the first arm 14, The lengths of the first link 10 and second link 11 of the toggle mechanism 8 are determined so that the stroke of is satisfied.

Further, by using the servo motor 18 in the above structure, the rotation angle of the first arm 14 can be arbitrarily set to arbitrarily adjust the stroke of the mold clamping device (second invention).

The above are examples, and the present invention is not limited to the illustrated structure.

Effects of the Invention Due to the combination of the toggle mechanism and the crank mechanism, mold clamping and mold opening operations are quick and efficient.

The combination of the toggle mechanism and the crank mechanism greatly expands the output of the servo motor as mold clamping force, so a mold clamping servo motor that has a particularly large output is not required.

Since the drive shaft of the crank mechanism is movable in the direction of the mold clamping axis a, one crank mechanism can drive the double toggle mechanism at the same time, and the stroke of the movable platen can be increased.

[Brief explanation of drawings]

FIG. 1 is a perspective view, FIG. 2 is a front view, and FIG. 3 is a diagram showing the operation of the mechanism. 3... Mold clamping device, 8... Toggle mechanism, 9... Crank mechanism, 13... Drive shaft, 14... First arm,
15...Second arm, 18...Servo motor, 19
...Double toggle mechanism, 20...Pongee receiving plate, 21...
・Slide rod, 23...Guide rod. -76

Claims (2)

[Claims] (1) The rear platen and front platen are connected by a tie rod parallel to the mold clamping axis, and the movable platen is slidably attached to the tie rod, and a bearing plate is installed between the rear platen and the movable platen in parallel with the mold clamping axis. The bearing plate is provided so as to be movable in parallel, and a vertical guide portion is provided on the bearing plate in a direction perpendicular to the mold clamping axis, while both ends of a toggle mechanism having a bending point in the middle are connected to the rear platen and the movable platen, and the toggle mechanism A drive shaft of a crank mechanism is pivotally supported at a fixed position of the bearing plate at a position where the crank mechanism is in an extended state on a line passing through the bending point and perpendicular to the mold clamping axis in the maximum extension state of the crank mechanism. 1 arm and a second arm, one end of the first arm is fixed to the drive shaft, the other end of the second arm is the movable end of the crank mechanism, and the movable side end is connected to the bearing plate together with the bending point of the toggle mechanism. A mold clamping device characterized by being rotatably connected to a vertical guide portion of the mold clamping device. (2) The mold clamping device according to claim 1, wherein the drive shaft of the crank mechanism is operatively connected to a mold clamping servo motor.