JPH0696255B2 - Mold clamping device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mold clamping device used for injection molding or the like, and more particularly to a side for performing a mold opening / closing operation in addition to a mold clamping cylinder exerting a pressing force on a mold. The present invention relates to a mold clamping device that includes a cylinder, moves a movable platen in a mold clamping direction by a predetermined distance by operating the side cylinder, and then performs mold clamping by operating the mold clamping cylinder.

(Prior Art) Conventionally, the movable platen is movably supported with respect to the fixed platen, and the mold opening / closing operation and the pressing operation of the mold are performed between the movable platen and the fixed platen. As a type of mold clamping device used for, for example, a so-called side cylinder type mold clamping device that includes a side cylinder that opens and closes the mold in addition to a mold clamping cylinder that exerts a clamping force on the mold is known. There is.

In such a side cylinder type mold clamping device, in recent years, in order to reduce the weight and size of the device and to reduce the amount of hydraulic oil in the mold clamping cylinder and the pressurization time during clamping, etc. A cylinder is provided in the movable platen, and its piston rod is slidably attached to a tie bar protruding from the fixed platen, so that the movable platen is attached to the tie bar via the piston rod of the mold clamping cylinder. A locking mechanism is provided that movably supports and locks the piston rod with a tie bar so as to prevent their relative movement. When the side cylinder is used to open and close the mold, the piston of the mold clamping cylinder is locked. The movable platen can be driven only by the side cylinders without locking the rod, while the mold clamping series can be operated after the mold is closed or just before the mold is closed. Da piston rod to engage with the tie bars, those having a structure to perform the clamping operation of the mold by the mold clamping cylinder is proposed.

By the way, in such a mold clamping device, the locking of the piston rod of the mold clamping cylinder with respect to the tie bar is, for example,
This is done by engaging the split nut with a rod having a thread groove formed on the outer peripheral surface. At the time of such engaging operation, driving by the side cylinder of the movable plate, that is, mold closing operation is performed. Since it is necessary to stop the operation once, the operation is not continuous, resulting in a loss time, and it is difficult to improve the molding cycle, and the productivity is low.

Therefore, in JP-A-61-242747, a tuning cylinder is provided between the movable platen and the piston rod of the mold clamping cylinder, and the moving platen is moved before the mold closing operation by the side cylinder is completed. The tuning cylinder causes the piston rod of the mold clamping cylinder to project toward the side opposite to the moving direction of the movable plate at the same speed, so that the piston rod of the mold clamping cylinder is moved relative to the tie bar. It is relatively in a stopped state, and under this condition,
A structure has been proposed in which the piston rod and the tie bar are locked while the mold closing operation is performed.

However, in the mold clamping device having such a structure, although the mold closing operation and the pressure clamping operation of the mold can be continuously performed, it is necessary to provide the tuning cylinder on the movable plate side, so that the structure is This is extremely complicated, and the driving speed of the tuning cylinder must be set to be the same as the driving speed of the side cylinder, which makes it difficult to design.

(Problem to be Solved) Here, the present invention has been made in view of the above circumstances, and a problem to be solved by the present invention is to perform a mold clamping between a movable platen and a fixed platen during a mold clamping operation. The operation of the mold clamping cylinder that exerts a force realizes a mold clamping device that can be released at the time of mold opening and closing operation with a simple structure, and the continuity of the operation from mold closing to pressing. It is to be realized.

(Solution Means) The present invention, in order to solve the above-mentioned problems,
A plurality of tie bars that are fixedly attached at one end to the support plate and at the other end to the fixed plate are inserted into the movable plate, and the movable plate is movably supported with respect to the fixed plate and fixed to the movable plates. A mold clamping device configured to perform a mold opening / closing operation and a pressure clamping operation with a board, wherein the movable board is moved closer to / separated from the fixed board between the fixed board and the movable board. While arranging side cylinders that can be moved in the direction, at the insertion portion of the tie bar in such a movable plate, double-acting mold clamping cylinders each provided with a hollow piston rod that can be reciprocally driven in the insertion direction of the tie bar are provided. In addition, such a hollow piston rod has a length that allows it to be inserted into the fixed plate at a predetermined size when the mold is clamped, and the tie bar is slidably inserted and arranged in the hollow portion of the piston rod. The movable platen is movably supported by the tie bar through the piston rods, and the movable platen is inserted into the fixed platen by abutting the tips of the piston rods of the mold clamping cylinders. The movable plate, which is integrally movable with the piston rod, is provided with a stopper member that defines an end position, and a releasable locking mechanism that engages with the piston rod and blocks its movement. While the piston rod is in contact with the stopper member, the piston rod is moved relative to the stopper member to complete the mold closing operation, and the engagement of the piston rod by the locking mechanism is completed. In the stopped state, the mold clamping cylinder is operated to drive the movable platen toward the fixed platen, whereby the mold clamping operation can be performed. That it has urchin configuration it is for its features.

In such a mold clamping device, a pressure accumulating means for supplying a pressure liquid to the cylinder chamber on the side of the mold clamping cylinder for driving the movable plate to the fixed plate side, and a pressure liquid for the pressure accumulating device. It is also possible to provide a pressure liquid supply circuit having a pressure generation means for supplying.

Also, instead of providing such a pressure liquid supply circuit,
A moving mechanism that supports a stopper member that defines the insertion end position of the piston rod in the fixed plate in the mold clamping cylinder so as to be movable in the axial direction of the piston rod, and operates the moving mechanism to operate the stopper member. It is also possible to provide a drive mechanism for moving the stopper rod and selectively hold the stopper member at a plurality of arrangement positions in the axial direction of the piston rod.

(Examples) In order to more specifically clarify the present invention,
Embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows a specific example of the mold clamping device according to the present invention. Note that, in FIG. 1, the mold open state and the mold closed state of the mold clamping device in the present embodiment are respectively shown in a half cross-sectional view, and in the portion showing the mold open state, the hydraulic circuit is Omitted.

In this figure, 10 is a stationary platen on which a stationary mold 12 is mounted, which is fixed on a machine base (not shown). In addition, a support plate 14 is arranged and fixed on the machine base in a state of facing the fixed plate 10 with a predetermined distance therebetween, and straddles between the fixed plate 10 and the support plate 14. Therefore, the four tie bars 16 are arranged in parallel with each other.

In addition, a movable mold is provided between the fixed platen 10 and the support plate 14.
A movable plate 20 on which 18 is mounted is provided, and its four corners are supported by tie bars 16, so that the movable plate 20 is supported so as to be movable toward and away from the fixed plate 10.

Furthermore, the fixed platen 10 includes a double-acting side cylinder.
A plurality of 22 are provided and the side cylinder 22
Since the piston rod 23 of the movable plate 20 is connected to the movable plate 20,
However, it can be reciprocally driven in the approaching / separating direction with respect to the fixed platen 10.

On the other hand, the movable plate 20 is provided with double-acting mold clamping cylinders 24 each having a piston 25 that is reciprocally driven in the insertion direction of the tie bar 16 at the insertion portion of the tie bar 16. Further, the piston rod 26 of this mold clamping cylinder 24 extends from both sides in the axial direction of the piston 25 with the same diameter, is arranged so as to penetrate through the movable plate 20, and then penetrates through the inside thereof in the axial direction. Since the tie bar 16 is slidably inserted into the through hole 28 provided in the movable plate 20, the movable platen 20 is attached to the tie bar 16 via the piston rod 26 of the mold clamping cylinder 24. It is movably supported.

Further, in this piston rod 26, the end in the axial direction on the fixed platen 10 side is extended by a predetermined length, and when the movable platen 20 is moved to the fixed platen 10 side, the tip part thereof is It is designed to be inserted into the fixed platen 10.

The position of the insertion end of the piston rod 26 into the fixed plate 10 is defined by the tip surface of the support wall 30 of the tie bar 16 in the fixed plate 10 being brought into contact with the support wall 30. There is. As is apparent from this, in this embodiment, the support wall 30 of the tie bar 16 constitutes a stopper member that defines the insertion end position of the piston rod 26 with respect to the fixed platen 10.

Furthermore, the tip portion of the piston rod 26 on the side of the fixed platen 10 is a locking portion 32 having a thread groove formed on the outer peripheral surface over a predetermined length, while the tip portion is inserted. A split nut 34 that meshes with the thread groove of the locking portion 32 is fixedly disposed in the fixed plate 10 in the axial direction. Although not clearly shown in the drawing, while the piston rod 26 is inserted into the fixed platen 10, the split nut 34 is operated by the locking cylinder 36 via an appropriate link mechanism. By engaging and locking the locking portion 32 of the piston rod 26, the movement of the piston rod 26 with respect to the fixed plate 10 (tie bar 16) can be prevented.

As is apparent from this, in the present embodiment, the locking portion 32 of the piston rod 26, the split nut 34
And the locking cylinder 36, the piston rod 26
A releasable locking mechanism is configured to prevent the movement of the.

Then, by such a locking mechanism, the piston rod 26
Of the mold clamping cylinder under the condition that the movement of the
By supplying pressure oil into the first cylinder chamber 38 of 24, a driving force in the direction of approaching the fixed plate 10 can be exerted on the movable plate 20, while the pressure in the second cylinder chamber 40. By supplying the oil, a driving force in a direction of separating from the fixed plate 10 can be exerted on the movable plate 20.

A limit switch 41 is provided between the end of the piston rod 26 on the side of the support plate 14 and the movable plate 20. The limit switch 41 allows a predetermined relative position of the movable plate 20 with respect to the piston rod 26. The position can be detected. Although the limit switch is used here, an encoder or the like can also be used.

Further, here, the piston of the mold clamping cylinder 24 is
In 25, a connection passage 44 having a pilot operated check valve 42 on the passage is provided between the first cylinder chamber 38 and the second cylinder chamber 40. The check valve 42 allows the cylinder chambers 38 and 40 to be connected / disconnected. Then, under the communication state by the connection passage 44, the free flow of the hydraulic oil between the cylinder chambers 38, 40 is allowed, so that the movement of the piston rod 26 with respect to the fixed platen 10 is performed by the locking mechanism. Even in a blocked state,
The side cylinder 22 allows the movable platen 20 to move a predetermined amount in the approaching / separating direction with respect to the fixed platen 10.

Further, a pressure accumulator 48 is connected to the first cylinder chamber 38 of the mold clamping cylinder 24 via a logic valve 46, and the solenoid of the electromagnetic switching valve 50 is excited to drive the solenoid valve 50 through the shuttle valve 52. The pilot pressure applied to the logic valve 46 is changed so that the logic valve 46 is switched to the communicating state so that the pressure oil stored in the pressure accumulator 48 can be supplied into the first cylinder chamber 38. It has become.

In addition, in particular, in the present embodiment, including the pressure accumulator 48, the hydraulic circuit 49 for supplying the pressure oil from the pressure accumulator 48 into the first cylinder chamber 38 is mounted on the movable plate 20, The outer pipe for supplying pressure oil to the pressure accumulator 48 that moves together with the movable plate, particularly the flexible pipe (rubber hose) 100, can be made thinner.

Then, the mold clamping device of this embodiment having such a structure is operated by a hydraulic mechanism as shown in FIG. 1, for example.

The hydraulic mechanism includes a first hydraulic pump 56 whose discharge pressure is set by the relief valve 54 and a first hydraulic pump 56 whose discharge pressure is set by the relief valve 58 and whose discharge amount is lower than that of the first hydraulic pump 56. A second hydraulic pump 60, and a relief valve 62 functioning as pressure generating means for supplying pressure oil to the pressure accumulator 48.
The hydraulic unit is composed of a third hydraulic pump 64 whose discharge pressure is set at and an electric motor 66 for driving those hydraulic pumps 56, 60, 64.

Then, the first hydraulic pump 56 and the second hydraulic pump 60 are respectively connected to the electromagnetic switching valve 76 via the check valves 72 and 74, and by the switching operation of the electromagnetic switching valve 76, The pressure oil discharged is the side cylinder 22.
Of the rod end side chamber 78 and the head side chamber 80 of the rod end side chamber 78.
The other of the head-side chamber 80 and the head-side chamber 80 is connected to the oil tank 82.

The relief valve 54 that regulates the discharge pressure of the first hydraulic pump 56 includes an electromagnetic switching valve 68, and the relief valve 58 that regulates the discharge pressure of the second hydraulic pump 60 includes a solenoid switching valve. 70 are respectively connected, and their solenoid operated switching valves are connected.
Under de-energization of the 68 and 70 solenoids, such relief valves
The vent circuits of 54 and 58 communicate with the oil tank 82, and the set pressures of these relief valves 54 and 58 are atmospheric pressure. As a result, the first hydraulic pump 56 and the second hydraulic pump 60 can be switched to the unload or on-load state based on the switching operation of the electromagnetic switching valves 68 and 70.

Further, in the mold clamping cylinder 24, the first cylinder chamber 38 is connected to the oil tank 82 through the electromagnetic switching valve 84, the rod end side chamber 78 of the side cylinder 22, and the electromagnetic switching valve 86. Meanwhile, the second cylinder chamber 40 is connected to the head side chamber 80 of the side cylinder 22 through the electromagnetic switching valve 88 and to the oil tank 82 through the electromagnetic switching valve 90.

Then, based on the switching operation of the electromagnetic switching valves 84, 86, 88, 90, one of the first and second cylinder chambers 38, 40 of the mold clamping cylinder 24 is provided with a first or second hydraulic pump. The pressure oil discharged at 56 and 60 is selectively supplied through the electromagnetic switching valve 76, and the other of the first and second cylinder chambers 38 and 40 is connected to the oil tank 82. It has become.

Further, a sequence valve 92 is provided between the second hydraulic pump 60 and the relief valve 58 that regulates the discharge pressure of the second hydraulic pump 60, and even when the set pressure of the relief valve 58 is atmospheric pressure. , The pressure oil specified by the sequence valve 92 is
It can be supplied to the lock cylinder 36 that drives the split nut 34 through the electromagnetic switching valve 94, and to the pilot passage of the check valve 42 that controls the communication state of the connection passage 44 through the electromagnetic switching valve 96. It has become.

On the other hand, in the third hydraulic pump 64, the pressure accumulator 4 is provided through a check valve 98 and a flexible pipe 100 such as a rubber hose.
Connected to 8. The pressure switch 102 and the electromagnetic switching valve 104 keep the pressure of the hydraulic oil supplied to the pressure accumulator 48 constant, so that the pressure is accumulated in the pressure accumulator 48 regardless of the operation of the mold clamping device. When the hydraulic oil is discharged, the pressure oil can be immediately supplied.

Hereinafter, with respect to the concrete operation of the mold clamping device in the present embodiment provided with such a hydraulic mechanism, Table 1 shows the control mode of the electromagnetic switching valve at each molding step, and based on the table, Further explanation will be added. In addition,
In Table 1 below, each solenoid operated directional control valve is indicated by a symbol in the drawings, and the fact that the solenoid is in an excited state is indicated by a (+) symbol.

First, in the mold clamping device, when the mold closing operation of the mold is performed, the solenoids of the electromagnetic switching valves 68, 70 and the solenoid 76a of the electromagnetic switching valve 76 are excited, and the first and second hydraulic pumps 56, While the pressure oil discharged from 60 is supplied to the rod end side chamber 78 of the side cylinder 22, the head side chamber 80 of the side cylinder 22 is connected to the oil tank 82.
Will be connected to. As a result, in the side cylinder 22, the movable platen 20 becomes the piston rod.
Along with 26, they are moved to the fixed platen 10 side at a high speed, whereby the high speed mold closing operation is performed.

Before the high-speed mold closing operation, the piston rod 26 of the mold clamping cylinder 24 has a support wall for the piston rod 26 described later.
At the time of contact with the mold 30, the molds 12 and 18 are held at a position protruding from the movable plate 20 toward the fixed plate 10 by a predetermined amount so that the molds 12 and 18 do not come into contact with each other. During operation, pressure oil is applied to the pilot passage of the check valve 42 of the connection passage 44 through the electromagnetic switching valve 96, and the connection passage 44 is maintained in the cutoff state. The split nut 34 is held by the locking cylinder 36 in a non-locking state with respect to the piston rod 26.

Next, the piston rod 26 of the mold clamping cylinder 24 is attached to the support wall 30.
The solenoid of the solenoid operated directional control valve 68 is demagnetized before being abutted on the side, and the discharge oil from the first hydraulic pump 56 is unloaded, so that the side cylinder 22 is driven only by the second hydraulic pump 60. Thus, the low speed type closing operation is switched.

Then, the piston rod 26 of the mold clamping cylinder 24 is attached to the support wall 30.
When the position of the insertion end into the fixed platen 10 is specified, the solenoid of the solenoid operated directional control valve 94 is excited.
The split cylinder 34 is locked by the lock cylinder 36 to the lock portion 32 of the piston rod 26, whereby the movement of the piston rod 26 with respect to the fixed platen 10 is blocked.

Further, at the same time as or immediately before the contact of the piston rod 26 of the mold clamping cylinder 24 with the support wall 30, the solenoid of the electromagnetic switching valve 96 is demagnetized, and the first and second cylinder chambers of the mold clamping cylinder 24 are demagnetized. 38 and 40 are communicated with each other at the connection passage 44.

Then, as a result, as described above, the piston rod 26
As a result that the movable platen 20 can be driven by the side cylinders 22 with respect to the piston rod 26 of the split nut 34,
The movable platen 20 can be moved to the fixed platen 10 side while performing the locking operation with respect to the mold, and the mold closing operation of the mold can be continued.

Next, when the movable platen 18 is brought into contact with the fixed mold 12 and the mold closing operation is completed, the solenoid of the electromagnetic switching valve 96 is excited and the connection passage 44 is brought into a non-communication state, while the electromagnetic switching valve is opened. The 84 and 90 solenoids are excited, and
The pressure oil is supplied from the second hydraulic pump 60 into the first cylinder chamber 38, the hydraulic pressure inside the hydraulic cylinder is increased to a predetermined value, and the second cylinder chamber 40 is communicated with the oil tank 82. It will be.

Then, the mold clamping cylinder 24 applies a driving force to the fixed platen 10 side with respect to the movable platen 20, so that the mold clamping operation is performed between the movable platen 20 and the fixed platen 10. It will be done.

Further, in particular, in the mold clamping device according to the present embodiment, during such pressure clamping operation, the solenoid of the electromagnetic switching valve 50 is excited, so that the pressure oil stored in the pressure accumulator 48 becomes the logic valve 46. Through the first cylinder chamber 38 of the mold clamping cylinder 24.
Will be guided inside.

That is, in such a mold clamping device, in order to cope with the difference in the thickness of the molds 12 and 18 to be mounted, the mold clamping cylinder 24
Since it is necessary to set a large operation stroke of, the relative stroke of the movable platen 20 with respect to the piston 25 of the first cylinder chamber 38 of the mold clamping cylinder 24 at the time of pressure clamping operation, especially when mounting a thin mold. It is necessary to increase the length, and the amount of oil supplied increases. Therefore, when a large pressure clamping force is generated, the required supply amount of hydraulic oil in the first cylinder chamber 38 increases, so that the first cylinder is activated during the pressure clamping operation. The amount of pressure oil to be supplied into the chamber 38 increases, but by supplying pressure oil from the pressure accumulator 48 as described above, the pressure oil supply time can be shortened.

Since the amount of oil required for such a pressure accumulator 48 is about 6 l in a mold clamping device with a mold clamping force of about 1000 tons, a pump as large as the third hydraulic pump 64 is required. It is possible to complete the pressure accumulation within the molding cycle without affecting the molding cycle.

Then, as described above, when the hydraulic oil is supplied into the first cylinder chamber 38 of the mold clamping cylinder 24 and the pressure of the first cylinder chamber 38 is increased to a predetermined pressure, the electromagnetic switching valve 50
The solenoid of is demagnetized, the supply of pressure oil from the pressure accumulator 48 is stopped, and the hydraulic fluid discharged from the second hydraulic pump 60 holds the molds 12 and 18 under pressure. .

Further, under such a pressure-holding state, a predetermined molding material is filled in the molding cavity formed between the molds 12 and 18 and a predetermined molding operation is performed according to a usual method.

Then, after cooling and solidifying the molding material, an electromagnetic switching valve
The solenoid 70 and the solenoid 76a of the solenoid switching valve 76 are demagnetized to stop the supply of pressure oil to the side cylinder 22 and the mold clamping cylinder 24, and the solenoid switching valves 84 and 86 are also provided.
The solenoid is excited to connect the rod end side chamber 78 of the side cylinder 22 and the inside of the first cylinder chamber 38 of the mold clamping cylinder 24 to the oil tank 82, respectively, so that depressurizing operation is performed. Become.

Further, after the depressurizing operation, the solenoids of the electromagnetic switching valves 68 and 70 are excited to cause the first hydraulic pump 56, the second hydraulic pump 60, and the discharge oil thereof to be on-loaded, and the electromagnetic switching is performed. The solenoid 76b of the valve 76 and the solenoids of the electromagnetic switching valves 86 and 88 are excited, while the solenoid switching valve
The 84 and 90 solenoids are demagnetized and their hydraulic pumps 5
Pressure oil from 6 and 60 is applied to the head side chamber 8 of the side cylinder 22.
0 and the second cylinder chamber 40 of the mold clamping cylinder 24, while the rod end side chamber 78 of the side cylinder 22 is supplied.
And the first cylinder chamber 38 of the mold clamping cylinder 24 is an oil tank.
It will be connected to 82.

Then, of both the side cylinder 22 and the mold clamping cylinder 24, the mold clamping cylinder 24 having a large effective area acts, and the mold opening force generated in the second cylinder chamber 40 of the mold clamping cylinder 24 is Depending on the product, the force is transmitted to the piston rod 26 due to the resistance in the pulled state, and the support wall 30 that is in contact with the tip of the piston rod 26 supports the cooperative opening operation. . The relative movement position of the movable plate 20 with respect to the piston rod 26 is defined by the limit switch 41 according to the thickness of the molds 12 and 18.
By adjusting 41, the piston rod of the movable platen 20
The operation stroke with respect to 26 can be set to be substantially constant regardless of the thickness of the molds 12 and 18 to be mounted.

At the same time as such a strong opening operation, the electromagnetic switching valve 94
The solenoid is demagnetized, whereby the locking cylinder 36 releases the locking of the split nut 34 to the piston rod 26.

After the strong opening operation and the unlocking operation of the split nut 34 are performed, the solenoid of the electromagnetic switching valve 68 is demagnetized, and the hydraulic oil discharged by the first hydraulic pump 56 is unloaded. At the same time, the solenoids of the electromagnetic switching valves 86, 88 are demagnetized to lock the mold clamping cylinder 24, while the pressure oil from the second hydraulic pump 60 is supplied to the head side chamber 80 of the side cylinder 22. Then, the movable platen 20 is moved together with the piston rod 26 in the direction away from the fixed platen 10, so that the low speed type opening operation is performed.

Further, in the low speed mold opening operation, after a predetermined amount of mold opening is performed, the solenoid of the electromagnetic switching valve 68 is excited, and the discharge oil of the first hydraulic pump 56 and the second hydraulic pump 60 is changed to the side. By being supplied to the head side chamber 80 of the cylinder 22, a high speed mold opening operation is performed, and before the completion of the mold opening, the solenoid of the electromagnetic switching valve 68 is demagnetized again to switch to the low speed mold opening operation, and thereafter, The solenoids of the electromagnetic switching valves 70 and 76 are demagnetized, the supply of pressure oil to the side cylinders 22 is stopped, and the movable platen 20 is stopped and held at a predetermined position, thereby completing the mold opening operation. It becomes.

In the mold clamping device in this embodiment, the neutral state of the device can be realized under the non-excited state of the solenoids in all the electromagnetic switching valves.
The hydraulic circuit is configured.

Although not shown, the molded product is taken out of the mold by a known ejector mechanism at the same time as the mold opening operation or after the mold opening.

As described above, according to the mold clamping device of the present embodiment, the locking stroke of the stationary platen 10 with respect to the piston rod 26 of the mold clamping cylinder 24 can be released, so that the operating stroke of the mold clamping cylinder 24 is increased. Can be set to a small value, so that the effect of reducing the size and weight of the entire apparatus, and further reducing the amount of hydraulic oil can be effectively exerted, and in addition to that, Such mold clamping cylinder 24
The locking of the fixed plate 10 with respect to the piston rod 26 and the releasing operation thereof, specifically, the locking of the split nut 34 and the releasing operation thereof can be performed in parallel during the mold closing operation and the mold opening operation. As a result, the continuity of the molding cycle can be advantageously ensured, and the reduction of loss time during molding and the improvement of productivity can be achieved very effectively.

Further, in particular, in the mold clamping device having such a structure, the movable platen
It is not necessary to install a tuning cylinder or the like in the
Piston rod in the mold clamping cylinder 24 provided inside
Since the relative movement of 26 with respect to the fixed plate 10 (tie bar 16) is prevented by abutting against the support wall 30 of the piston rod 26, its structure is much simpler than the conventional one. Can be realized.

Further, in such a mold clamping device, the mold clamping cylinder is
Since the locking mechanism for the piston rod 26 of 24 is also provided on the fixed platen 10 side, it is not necessary to provide drive means other than the mold clamping cylinder 24 to the movable platen 20, and the structure of the movable platen 20 is thereby improved. Can be advantageously simplified and its weight can be reduced.

Furthermore, in the mold clamping device of the present embodiment, the piston rod 26 slidably inserted into the tie bar 16 is formed with a length of the mold opening stroke or more,
The excellent guide performance for the movable platen 20 can be exhibited, the parallel accuracy with respect to the machine base can be advantageously improved when the movable platen 20 is moved, and the smooth mold opening / closing operation can be advantageously realized. is there.

Next, FIG. 2 shows a means for mechanically performing the die thickness adjusting means in the embodiment shown in FIG. 1 instead of using hydraulic pressure. In this figure, members having the same structures as those in the above-mentioned embodiment are designated by the same reference numerals as those in the above-mentioned embodiment, and detailed description thereof will be omitted.

That is, in the mold clamping device according to the present embodiment, the support wall 30 that supports the end portion of each tie bar 16 in the fixed platen 10.
An accommodation space 108 extending in the axial direction of the tie bar 16 by a predetermined length is formed inside the tie bar 16, and the accommodation space 1
In 08, the piston rod 26 of the mold clamping cylinder 24 is abutted to define the position of the insertion end into the fixed platen 10,
The annular plate-shaped stopper fittings 106 are respectively attached to the tie bars 16
It is arranged in a state of being inserted into.

Further, in the accommodation space 108, a plurality of support rods 110 extending in parallel with the tie bar 16 around the tie bar 16 are rotatably supported at both ends thereof, and stopper fittings accommodated therein. It is placed through 106.

The stopper fitting 106 is supported at a predetermined position by screwing the stopper fitting 106 into the thread groove formed on the outer peripheral surface of the supporting rod 110, and It is movable in the axial direction according to the rotation operation by the drive motor 112.

In the figure, 114 and 116 are pulleys attached to the rotary shaft of the drive motor and the support rod 110, respectively, and 118 is bridged between the pulleys 114 and 116 to rotate the drive motor 112. A drive belt for transmitting a driving force to the support rod 110.

Further, as is clear from this, in the present embodiment, the moving mechanism that supports the stopper fitting 106 so as to be movable in the axial direction by the plurality of support rods 110 is also the drive motor.
The 112, the pulleys 114 and 116, and the drive belt 118 constitute a drive mechanism that operates the activation mechanism.

Therefore, in the mold clamping device of the present embodiment having such a structure, the stopper fitting 106 is arranged according to the thickness of the molds 12 and 18 mounted on the fixed platen 10 and the movable platen 20. The position can be changed, whereby the working stroke of the mold clamping cylinder 24 can be kept substantially constant regardless of the difference in the mold thickness.

And, therefore, in the mold clamping device of the present embodiment, it is of course possible to effectively achieve the same effects as those of the first embodiment, and in addition to that, The working stroke can be set even shorter, the amount of working oil can be reduced, and the boosting capacity of the mold clamping cylinder 24 at the time of the tightening operation can be set small, so that the pressure accumulator (48) and It is possible to advantageously achieve the shortening of the pressure increasing time of the mold clamping cylinder 24 without providing a pressure liquid supply circuit such as a third hydraulic pump (64), and the limit switch (41) is unnecessary. It will be.

Since the operation of the mold clamping device in this embodiment is performed in the same steps as in the first embodiment, the electromagnetic switching valve in each molding step is shown in Table 2 below. The control mode is shown, and its specific description is omitted.

Although the embodiments of the present invention have been described above in detail, these are literal examples, and the present invention should not be construed as being limited to such specific examples.

For example, in the embodiment described above, the piston 25 of the mold clamping cylinder 24 is provided with the connection passage 44 that communicates the two side cylinder chambers 38 and 40, but the connection passage 44 is formed in the cylinder chambers 38 and 40. Of course, it is also possible to configure it by an external hydraulic circuit that communicates with the inside.

Further, as a locking mechanism for locking the piston 25 of the mold clamping cylinder 24 to the fixed platen 10, in addition to the meshing structure by the split nut 34 as illustrated, a publicly known locking structure such as a split gate structure or spline engagement may be used. Any of these can be adopted.

Further, the moving mechanism that movably supports the stopper metal fitting 106 and the drive mechanism that operates the stopper metal fitting 106 are not limited to the structures shown in the examples. For example, a step motor is used as the drive motor 112, and the stopper metal fitting is used. It is also effective to increase the accuracy of the arrangement position of 106, or it can be driven manually.

Furthermore, the specific structure of the hydraulic circuit for operating the mold clamping device having the structure according to the present invention is not limited to that of the above embodiment.

In addition, a pressure fluid supply circuit such as a pressure accumulator 48 and a support rod
The movement of the stopper metal fitting 106 by 110 etc. and the drive mechanism,
It should be understood that the object of the present invention can be achieved even in a structure having neither.

Although not listed one by one, the present invention can be carried out in variously modified, modified, improved, etc. modes based on the knowledge of those skilled in the art. It goes without saying that all of them are included in the scope of the present invention without departing from the spirit.

(Effects of the Invention) As is apparent from the above description, in the mold clamping device according to the present invention, the movement of the piston rod of the mold clamping cylinder that is moved with respect to the fixed plate together with the movable plate during the mold closing operation. Are blocked by abutting against the stopper member, and after such abutting, a continuous die closing operation based on the relative movement of the movable plate with respect to the piston rod, and a platen for fixing the piston rod by a locking mechanism. Since it can be locked in parallel with each other, it is not necessary to provide a tuning cylinder or the like in the movable plate, and the structure thereof can be remarkably simplified as compared with the conventional one, and such a simple structure can be achieved. With such a structure, shortening of the molding cycle and improvement of productivity can be achieved advantageously.

Further, a pressure fluid supply circuit is provided in such a mold clamping device, and when the pressure clamping operation is performed, the pressure fluid is supplied from the pressure accumulating means to the cylinder chamber on the pressure clamping force generation side of the mold clamping cylinder. By doing so, it is possible to shorten the pressure increasing time of the mold clamping cylinder during such pressure clamping operation, and in particular, the operating stroke of the piston rod is set to a large value in order to accommodate the difference in the thickness of the mold to be mounted. It is effective for mold clamping cylinders.

On the other hand, in such a mold clamping device, a stopper member that defines the moving end position of the piston rod of the mold clamping cylinder is provided.
It is also possible to move the piston rod in the axial direction, and by changing the position of the piston rod, it is possible to absorb the difference in the thickness of the mold to be mounted, thereby controlling the operation of the mold clamping device. In addition to being easy, it is possible to reduce the amount of hydraulic oil and shorten the pressure increasing time by shortening the operating stroke of the piston rod.

[Brief description of drawings]

1 is an explanatory view schematically showing an embodiment of the mold clamping device according to the present invention, and FIG. 2 shows another embodiment of the mold clamping device according to the present invention, corresponding to FIG. It is a schematic explanatory drawing. 10: Fixed plate, 12: Fixed mold 16: Tie bar, 18: Movable mold 20: Movable plate, 22: Side cylinder 24: Mold clamping cylinder, 26: Piston rod 28: Insertion hole, 30: Support wall 32: Engagement Stopper, 34: Split nut 36: Locking cylinder, 38: First cylinder chamber 40: Second cylinder chamber 44: Connection passage, 48: Accumulator 106: Stopper metal fitting, 110: Support rod 112: Drive motor

Claims (3)

[Claims] 1. A plurality of tie bars, one end of which is fixedly attached to a support plate and the other end of which is fixedly attached to a fixed plate, are inserted into a movable plate, and the movable plate is movably supported with respect to the fixed plate,
A mold clamping device configured to perform a mold opening / closing operation and a pressure clamping operation between the movable platen and the fixed platen, wherein the movable platen is provided between the fixed platen and the movable platen. A double-acting mold clamping system, in which a side cylinder that moves in the approaching / separating direction is arranged, while a hollow piston rod that can be reciprocally driven in the insertion direction of the tie bar is provided at the insertion site of the tie bar in the movable plate. Each of the cylinders has a hollow piston rod,
It has a length that allows it to be inserted into the fixed plate when the mold is closed, and the tie bar is slidably inserted and arranged in the hollow part of the piston rods so that the tie bars are inserted through the piston rods. The movable platen so as to be movable with respect to the tie bar, and a stopper member that defines the insertion end position of the fixed platen by abutting the tip of the piston rod of the mold clamping cylinder. A movable locking plate that is provided with a releasable locking mechanism that engages with the piston rod to prevent its movement and that moves the movable plate integrally with the piston rod against the stopper member of the piston rod. Under contact condition,
By moving relative to the piston rod,
While trying to complete the mold closing operation of the mold,
While the piston rod is locked by the locking mechanism, the mold clamping cylinder is operated to drive the movable platen toward the fixed platen so that the mold clamping operation can be performed. The mold clamping device characterized in that 2. A pressure accumulating means for supplying a pressure liquid to a cylinder chamber on the side of the mold clamping cylinder for driving the movable plate to the fixed plate side, and a pressure generating means for supplying a pressure liquid to the pressure accumulating means. The mold clamping device according to claim 1, further comprising a pressure liquid supply circuit having a. 3. A stopper member for defining the insertion end position of the piston rod in the fixed plate in the mold clamping cylinder,
A moving mechanism that movably supports the piston rod in the axial direction and a drive mechanism that operates the moving mechanism to move the stopper member are provided, and the stopper member is provided in a plurality in the axial direction of the piston rod. The mold clamping device according to claim (1), wherein the mold clamping device is adapted to be selectively held at the installation position.