JPH0899165A - Die-clamp device in forming apparatus - Google Patents

Abstract

PURPOSE: To provide a die clamp device in a forming apparatus which can shift a movable disk at a high speed and can smoothly change the high speed shifting movement to the low speed shifting movement safely without shock. CONSTITUTION: The die clamping cylinder 50 has a small diameter part S on a head side and a large diameter part L on a rod side formed by dividing the inside of a cylinder 51 in the axial direction. Each of a small piston 52A and a large piston 52B is slidably arranged, and when the integrated both pistons 52A, 52B approach the advancing limit, the small diameter piston 52A leaves the small diameter part S and shifted to the large diameter part L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device of a molding machine such as a die casting machine or an injection molding machine, and particularly, a mold opening / closing operation can be completed in a short time, and a high speed moving operation of a movable platen to a low speed mold clamping operation can be performed. The present invention relates to a mold clamping device of a molding device having a mold clamping cylinder that can be smoothly switched.

[0002]

2. Description of the Related Art Generally, a mold clamping device of an injection molding machine requires a high-speed and shock-free opening / closing operation of a mold and a clamping force (mold clamping force) comparable to a resin pressure at the time of injection, like a die-casting machine. The method is roughly classified into a direct pressure type and a toggle type. Compared with the direct pressure type, the toggle type requires less oil when opening and closing the mold, and the direct pressure type requires the supply of high-pressure oil when holding the mold clamping force, whereas the toggle type has a self-locking function of the toggle mechanism. Since it works, it has various advantages such as energy saving compared to the direct pressure type. FIG. 5 is a vertical cross-sectional view showing a toggle type mold clamping device. The upper half of the center line shows the state before the mold closing starts.
The lower half is in the mold closed state (toggle link extension completed state)
Is shown. The mold clamping device 200 in the figure includes a link housing 1, a fixed platen (fixed platen) 2, a movable platen (movable platen) 3, a mold 4 (a fixed mold 4b and a movable mold 4a), a bed 5, a toggle mechanism 6, It comprises a crosshead 7, a mold clamping cylinder (die lock cylinder) 8, a piston rod 9 and a guide rod 10. In the double toggle type mold clamping device 200 of the injection molding machine, as shown in the drawing, a pair of upper and lower toggle mechanisms 6 including three toggle links 6a, 6b, 6c are provided between the movable platen 3 and the link housing 1. A mold clamping cylinder (die lock cylinder) 8 is attached to the outer end surface of the link housing 1 substantially in the center thereof.
The tip of the piston rod 9 of the mold clamping cylinder 8 is connected to the crosshead 7, and the crosshead 7 is moved back and forth along the guide rod 10 that is inserted through the crosshead 7 so that the toggle mechanism 6 can be moved through the crosshead 7. Is operated to move the movable platen (movable platen) 3 with respect to the fixed platen 2 to perform the mold clamping operation. Specifically, as shown in FIG. 6, the toggle links 6 a, 6 b, 6 of the toggle mechanism 6 are
The mold 4 is tightened by advancing the mold clamping cylinder 8 from the mold open state in which c is folded. The amount of oil sent to the mold clamping cylinder 8 is adjusted to obtain a high-speed and smooth mold clamping operation. Immediately before the touch of the mold 4 in FIG. 7, if there is a product left between the molds 4a and 4b or if there is a foreign substance, the mold 4 may be damaged. Set low and low oil and oil pressures and tighten. From the state where the dies in FIG. 7 are touched, the mold clamping force is generated and the dies 4
In order to firmly clamp a and 4b, high-speed and high-pressure oil is sent to the mold clamping cylinder 8, and the toggle link 6a of the toggle mechanism 6
6b is in an extended state and the length Lt of the tie bar 11 between the link housing 1 and the fixed platen 2 is extended to generate a mold clamping force in the mold. The state in which the tie bar 11 is stretched and the mold clamping is completed is as shown in Fig. 8. At this time, the toggle link 6
Since a and 6b have been stretched and are in a straight line state and maintain this state without sending high pressure oil to the mold clamping cylinder 8 to form a self-locking state, energy saving is superior to the direct pressure type. The mold clamping force is adjusted by changing the extension amount of the tie bar 11 from the state of touching the mold shown in FIG. To increase the mold clamping force, link housing 1
Is further advanced in the direction of the fixed platen 2 and is retracted when it is reduced. The link housing 1 is moved by driving a chain wound around four tie bar nuts fastened to the four tie bars 11 by a die height motor (not shown). The amount of movement is controlled by the amount of rotation of the die height motor.

On the other hand, as shown in FIG. 9, the direct pressure type mold clamping device is guided by tie bars 11 penetrating the four corners of the movable platen 3 so that the movable platen 3 can be moved forward and backward by driving a mold clamping cylinder 8. Has been done. In addition, as shown in FIG.
Is a tie bolt 11A, and by rotating the tie bolt 11A in the same direction, the movable platen 3 which is screwed with the tie bolt 11A is moved forward and backward, and the rotational force of the motor 12 is transferred to one of the tie bolts 11A via the speed reducer 14. To the sprocket 16 and the other three tie bolts 11A.
By applying rotation in the same direction by the chain 18 and the chain 18, the movable platen 3 screwed with the four tie bolts 11A is moved back and forth.

[0004]

In the mold clamping device having the conventional structure as described above, the hydraulic drive of the mold clamping cylinder or the like is used as the power means for moving the movable plate, but in the case of the hydraulic drive system. As shown in FIG. 11, there are many control valves and hydraulic pipes in the hydraulic unit that operates the mold clamping cylinders, and oil leakage and pressure loss that occur in these devices cause a decrease in efficiency. When an electric drive system is used instead of hydraulic drive, the tie bolt is driven to rotate as power for moving the movable platen, and the drive is indirectly driven by a speed reducer, chain drive, or belt drive, so the overall structure is complicated. As a result, the space occupied by the molding apparatus becomes large, and there is a difficulty in saving space. In addition, a large electric motor specification is required to open and close and mold-clamp the movable plate by electric drive, and even if a ball screw mechanism is adopted for the tie bolts to reduce this, the movable plate can be moved smoothly but is large. The molding apparatus requires a large ball screw rotation torque equivalent to the mold clamping force, and inevitably requires a large ball screw diameter, which has been an obstacle to increasing the size of the equipment. In the present invention, such a problem is solved, when the movable platen is moved, it is moved at a high speed with a relatively small force, and immediately before the completion of the movement (immediately before contact between the two dies), at a low speed,
Moreover, it is intended for a mold clamping device that produces a large output.

[0005]

In order to solve such a problem, in the present invention, in the first aspect of the present invention, the movable plate is arranged so as to be freely contactable and separable with respect to the fixed plate, and the movable plate is attached. In a mold clamping device of a direct pressure type or toggle type molding device equipped with a mold clamping cylinder that is moved or clamped by pressing directly or through a toggle mechanism, the mold clamping cylinder has a small diameter on the head side that is partitioned in the axial direction. Section and a large diameter section on the rod side, and a small diameter piston and a large diameter piston which are slidable in the axial direction are respectively disposed inside the small diameter section and the large diameter section, and the two pistons are connected. The small-diameter pistons leave the small-diameter portion of the mold clamping cylinder and move to the large-diameter portion when both pistons connected or directly joined via a rod and integrated with each other reach near the forward limit. It is configured to move. Further, according to the second aspect of the invention, an oil passage for communicating hydraulic oil in the small diameter portion of the mold clamping cylinder to the large diameter portion is formed in the cylinder of the small diameter portion when the small diameter piston reaches the vicinity of the forward limit. .

[0006]

In the present invention, when moving the movable plate from the mold open state to the mold closed state, the working oil is introduced into the small diameter portion on the head side of the mold clamping cylinder, and the small diameter piston is moved forward to move the piston rod. The crosshead is moved forward in the toggle type mold clamping device, and the movable platen is moved directly in the forward direction (mold closing direction) in the direct pressure type mold clamping device.
Just before the movable platen moves and the movable platen movable mold and the fixed platen fixed mold come into contact with each other, in the first invention, the small diameter piston moves from the small diameter part to the large diameter part, and the small diameter part moves. And the large-diameter portion communicate with each other, and in the second invention, the small-diameter portion and the large-diameter portion communicate with each other by the oil guide passage, and the pressure receiving area in the mold clamping cylinder for advancing the piston rod changes from the small-diameter piston to the large-diameter piston. The piston rod, which has been expanded and has been advanced so far, is suddenly decelerated, and then both dies come into contact with each other to stop the movable plate, and the pressing force increases to act as a mold clamping force.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.
explain about. 1 to 4 relate to an embodiment of the present invention,
FIG. 1 is a vertical cross-sectional view of a mold clamping cylinder, and FIGS.
FIG. 4 is a vertical sectional view of a mold clamping cylinder according to an example, and FIG.
It is a perspective view of a table. What is shown in FIG. 1 is the fruit of the first invention.
With the mold clamping cylinder 50 according to the embodiment, the mold clamping cylinder 50
The binder 51 has a small diameter portion S on the head side and a large diameter portion L on the rod side.
Divided into small diameter parts S (diameter D₁) Has a diameter D₁Small pie
The stone 52A has a large diameter portion L (diameter D ₂) Has a diameter D₂of
The large piston 52B is arranged so as to be slidable in the axial direction.
The ton 52A and the large piston 52B are connected by a connecting rod 54.
Are joined together to form an integral unit that is movable in the axial direction.
Furthermore, on the rod side (right side in the drawing) of the large piston 52B,
The stone rod 53 is connected to the pistons 52A and 52A.
It moves in the axial direction together with B. On the side wall of the cylinder 51
Are three oil passages (heads) that supply and discharge hydraulic oil to and from the cylinder 51.
Oil passage 55a, intermediate oil passage 55b, rod oil passage 55
c) is provided. The tip of the piston rod 53 is a cross
Joined with head 7 (toggle type) or directly movable
Connected to the board 3 (direct pressure type). On the other hand, the cylinder 51
The oil passage 55c on the head side and the oil passage 55a on the head side are each solenoid valves.
(4 port switching valve) 80 is connected. In addition, the intermediate oil passage 5
5b is connected to the oil tank 100 via the check valve 90
It One of the ports of the solenoid valve 80 is driven by the electric motor 70a
Connected to the hydraulic pump 70. 72 is relief
The valve 74 is a pressure regulating valve.

The mold clamping cylinder 50 constructed as described above
The operation of will be described. First, from the mold open state to the mold closed state
When moving the movable platen 3 toward the solenoid valve 80 solenoid
Hydraulic oil that excites the noid A and is regulated by the pressure regulating valve 74
Is supplied to the small diameter portion S via the head side oil passage 55a.
The piston rod 53 is pressed by the hydraulic oil and moves forward to move the movable platen 3.
Performs the mold closing operation. The forward movement of the movable platen 3 progresses, and the forward movement is approaching the limit.
The position of the small piston 52A inside the cylinder 51
Moves toward the forward side (to the right in Fig. 1), resulting in a smaller diameter
The small piston 52A in the portion S is shown by the chain double-dashed line in FIG.
As a result of moving to the large diameter portion L as described above, the hydraulic oil moves to the head side.
Communication, resulting in a sudden increase in the hydraulic oil inflow volume
The forward speed of the rod 53 is suddenly reduced. And yes
The movable mold 4a of the moving platen 3 is touched to the fixed mold 4b of the fixed platen 2.
After the movable platen 3 has stopped, the piston in the cylinder 51
The pressure receiving area of the rod 53 in the forward direction is (π / 4) D₁ ²
From (π / 4) ・ D₂ ²To the same pressure
A large forward force, that is, the mold clamping force is generated by the oil on the movable platen 3.
Will work to. Movable in toggle type mold clamping device
A small force that overcomes the sliding resistance when the board 3 moves
(For example, multiply the weight of the movable plate by 20 tons by a friction coefficient of 0.2.
Force of about 4 tons) is required, but mold clamping force of 1000 tons
Mitigation by using a toggle mechanism to give
1/20 to 1/30 of the force applied, that is, 4 tons
A large force of 30 to 50 tons, which is about 10 times that of
However, in the mold clamping cylinder 50 of the present invention,
There is no need to increase the pressure of hydraulic oil when tightening,
Can be dealt with by increasing (the large diameter portion of the cylinder 51
Inner diameter of L D₂Is the inner diameter D of the small diameter portion S₁Square root of 10 or more
Above). Inner diameter D of cylinder 51 of large diameter portion L₂Against
Inner diameter D of the cylinder 51 of the small diameter portion S ₁Ratio and small diameter part S
The position of the boundary of the large diameter portion L is determined by the specifications of the mold clamping device (model number, mold clamping
Force, sliding resistance of movable plate, etc.)
Needless to say. When the mold is closed and the mold is opened
Solenoid B of solenoid valve 80 is excited to
52B is pressed backwards, and the hydraulic oil on the head side is
The lot check valve 90 is opened and returned to the oil tank 100.
It The boundary between the small diameter portion S and the large diameter portion L is shown in FIG.
If chamfered like this, the small diameter part S is separated and the large diameter part is removed.
The small piston 52A that has moved to L has a large diameter when the mold is opened.
The small diameter portion S can be smoothly fitted from L.

FIG. 2 shows another embodiment of the present invention (corresponding to the second invention), and only different points from FIG. 1 will be described. The mold clamping cylinder 60 has a small piston 5 sliding in the small diameter portion S.
When the 2A moves near the forward limit, the oil guide path 56 through which the hydraulic oil of the small diameter portion S communicates with the large diameter portion L is bored in the cylinder 61, and has the same function as the mold clamping cylinder 50 of FIG. In addition, since the small piston 52A can decelerate the piston rod 53 without completely separating the small diameter portion S, the small piston 52A can smoothly reverse in the small diameter portion S when returning to the mold opening operation. There are advantages. FIG. 3 shows the mold clamping cylinder 50 of FIG. 1 whose axial length is shortened to reduce the diameter thereof. The connecting rod 54 is eliminated and the small piston 52A is eliminated.
And the large piston 52B are directly connected to each other. The mold clamping cylinder 50A shown in FIG. 3 may be of a type provided with an oil guide path 56 as shown in FIG. The mold clamping cylinders 50 and 60 shown in FIG. 1 and FIG. 2 are not only adopted in a toggle type mold clamping device by connecting the tip of the piston rod 53 to the crosshead 7, but the cylinders 51 and 61 are fixed to the fixed platen 2. It can also be adopted in a direct pressure type mold clamping device that is fixed and connects the piston rod 53 to the movable platen 3. FIG. 4 shows an embodiment in which the mold clamping cylinder 50 is used in a direct pressure type mold clamping device.

As described above, in the mold clamping device of the present invention, the movable platen is automatically decelerated from high speed to low speed near the forward limit without any external command, so that the two molds come into contact with each other. It is safe with less impact on the machine and less likely to damage equipment, and has a high energy-saving effect because it generates a large mold clamping force without increasing the hydraulic oil pressure even during mold clamping. Further, as shown in FIG. 11, the hydraulic circuit has a merit that the initial cost is low because it can have a simple structure as compared with a conventional one such as a run-around circuit for achieving high speed.

[0011]

As described above, according to the present invention,
High-speed operation is possible when the mold is closed, there is little impact when contacting the mold, a large mold clamping force can be obtained with a relatively low hydraulic pressure, and the hydraulic circuit is simple and the equipment cost is low.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a mold clamping cylinder according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a mold clamping cylinder according to another embodiment of the present invention.

FIG. 3 is a vertical sectional view of a mold clamping cylinder according to another embodiment of the present invention.

FIG. 4 is a perspective view of a direct pressure type mold clamping device according to an embodiment of the present invention.

FIG. 5 is a side sectional view of a conventional toggle type mold clamping device.

FIG. 6 is a plan view of a conventional toggle type mold clamping device.

FIG. 7 is an explanatory view (plan view) of a conventional toggle type mold clamping device.

FIG. 8 is an explanatory view (plan view) of a conventional toggle type mold clamping device.

FIG. 9 is a schematic perspective view of a conventional direct pressure type mold clamping device.

FIG. 10 is a schematic perspective view of another conventional direct pressure type mold clamping device.

FIG. 11 is a hydraulic circuit diagram (runaround circuit diagram) of a conventional mold clamping cylinder.

[Explanation of symbols]

1 link housing 2 fixed plate 2a tie bolt fixed plate 2A fixed plate 2N nut 3 movable plate 4 mold 4a movable mold 4b fixed mold 5 bed 6 toggle mechanism 6a, 6b, 6c toggle link 7 crosshead 7a fixed nut 8 mold clamp Cylinder 9 Piston rod 10 Guide rod 11 Tie bar 11A Tie bolt 11B Sliding bush 12 Motor 14 Reducer 16 Sprocket 18 Chain 50 Mold clamping cylinder 50A Mold clamping cylinder 51 Cylinder 52A Small piston 52B Large piston 53 Piston rod 54 Connecting rod 55a Head side oil Line 55b Intermediate oil line 55c Rod side oil line 56 Oil guide line 60 Mold clamping cylinder 61 Cylinder 70 Hydraulic pump 70a Electric motor 72 Relief valve 74 Pressure adjusting valve 80 Solenoid valve 90 Check valve (pilot check valve) 100 oil tank 200 mold clamping device D ₁ small diameter inner diameter (small piston diameter) D ₂ large diameter inner diameter (large piston diameter) S small diameter L large diameter

Claims (2)

[Claims] 1. A direct pressure type or toggle type equipped with a mold clamping cylinder in which a movable plate is arranged so as to come in contact with and separate from a fixed plate, and the movable plate is moved or clamped by directly or via a toggle mechanism. In the mold clamping device of the molding apparatus, the mold clamping cylinder has a small diameter portion on the head side and a large diameter portion on the rod side that are respectively partitioned in the axial direction, and the small diameter portion and the large diameter portion are respectively inside. A small-diameter piston and a large-diameter piston that are slidable in the axial direction are provided, and both pistons are connected or directly joined via a connecting rod, and the two integrated pistons have a forward limit. A mold clamping device of a molding apparatus, wherein the small diameter piston moves out of the small diameter part of the mold clamping cylinder and moves to the large diameter part when reaching the vicinity. 2. An oil guide passage through which hydraulic oil in the small diameter portion of the mold clamping cylinder communicates with the large diameter portion when the small diameter piston reaches the vicinity of the forward limit, is bored in the small diameter portion of the cylinder. Mold clamping device for molding equipment.