JPH0482099B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a mold clamping device for an injection molding machine, and particularly to a mold clamping device in which the opening and closing operations of the mold are performed by an auxiliary cylinder, and the clamping operation is performed by a main cylinder. It is related to the device.

(Prior art) In a type of mold clamping device for an injection molding machine, a movable plate is disposed between a fixed plate and a pressure receiving plate connected by tie rods, and a movable plate is disposed between the movable plate and the pressure receiving plate. By moving the movable platen close to and melting the fixed platen using the auxiliary cylinder, the mold can be opened and closed between the movable platen and the fixed platen. There is a device in which the mold is clamped between the movable plate and the fixed plate by pressing the movable plate against the fixed plate with a mold clamping cylinder. In this type of mold clamping device, the overall length of the mold clamping cylinder is shorter than that of a direct pressure type in which a mold clamping cylinder placed between the pressure receiving plate and the movable plate directly presses the movable plate. There is a so-called hydromechanical mold clamping device that can reduce the amount of hydraulic oil used.

FIG. 7 shows an example of such a hydromechanical mold clamping device. That is, there, 1 is an auxiliary cylinder that moves the movable platen 2 in the left-right direction in the figure and performs high-speed mold opening and closing of the mold 4 between it and the fixed platen 3. It is disposed between the fixed platen 3 and a pressure receiving plate 6 connected to the fixed platen 3. On the other hand, a mold clamping cylinder 7 that performs a clamping operation on the mold 4 is disposed on a pressure receiving plate 6, and an intermediate pressure plate 9 is disposed on the front end surface of a mold clamping ram 8 of the mold clamping cylinder 7. ing.

Here, a distance rod 1 is attached to the movable platen 2 so as to extend toward the pressure receiving plate 6.
On the other hand, a through hole 11 is formed in the intermediate pressure receiving plate 9 to allow the insertion of the distance rod 10, and further, a through hole 11 is formed in the intermediate pressure receiving plate 9 to allow the insertion of the distance rod 10. A lock plate 12 that is selectively movable between an insertion permitting position that allows insertion of the distance rod 10 into the hole 11 and a locking position that prevents this.
is provided.

According to such a hydromechanical mold clamping device, the movable platen 2 is moved at high speed by operating the auxiliary cylinder 1 while the lock plate 12 is moved to the insertion permissible position.
The mold 4 can be opened and closed at high speed (see the lower half of Fig. 7), and the mold clamping ram 8 of the mold clamping cylinder 7 can be moved with the lock plate 12 moved to the above-mentioned lock position. By operating the protrusion, the pressing force of the mold clamping cylinder 7 is applied to the movable platen 2 via the distance rod 10, and the mold 4 can be clamped (as shown in FIG. 7, top). (see half).

In this mold clamping device, during high-speed mold opening/closing operations of the mold 4 by the auxiliary cylinder 1,
Since there is no need to move the clamping ram 8, the length of the clamping cylinder 7 can be shortened compared to the direct pressure type, and the amount of hydraulic oil used can be significantly reduced.

In FIG. 7, 13 is a retraction cylinder for forming a gap between the lock plate 12 and the distance rod 10 to allow movement of the lock plate 12 when the mold 4 is opened. 14 is a stopper for setting the gap width.

(Problem) However, in such a conventional hydromechanicam type mold clamping device, as mentioned above,
Since the mold clamping cylinder was disposed on the pressure receiving plate, due to its structure, it was not possible to save the labor of an intermediate strength member such as the intermediate pressure receiving plate 9, which resulted in a complicated device and poor manufacturability. There was a problem.

(Solution Means) Against this background, the present invention provides a mold clamping device that has the same advantages as the above-mentioned conventional hydromechanical mold clamping device,
It was designed to provide a mold clamping device that is easier to manufacture than conventional hydromechanical mold clamping devices, and its gist is that the clamping device is designed to provide a mold clamping device that is easier to manufacture than conventional hydromechanical mold clamping devices. A movable platen is disposed at the movable platen, and an auxiliary cylinder arranged between the movable platen and the pressure receiving plate allows the movable platen to approach and approach the fixed platen.
By melting and moving, the mold is opened and closed between the movable platen and the fixed platen, and by pressing the movable platen against the fixed platen with a plurality of mold clamping cylinders. , in a mold clamping device for an injection molding machine that performs a mold clamping operation between a movable platen and a fixed platen, the plurality of mold clamping cylinders are connected to a rear surface of the movable platen facing the pressure receiving platen. At the same time, a distance rod of a predetermined length is provided so as to extend from the piston rod of each of the mold clamping cylinders toward the pressure receiving plate, and the distance rod is inserted into the pressure receiving plate. A through hole is formed to allow the distance rod to be inserted into the through hole when the movable platen is brought close to the pressure receiving plate by the auxiliary cylinder; A locking member is disposed on the pressure receiving plate and selectively moved by a predetermined driving means between a position that allows the distance rod to be inserted into the through hole and a position that prevents such insertion. When the locking member prevents the insertion of the distance rod, the piston rod of the mold clamping cylinder is operated to project, so that the distance rod is brought into contact with the locking member, and the piston rod of the mold clamping cylinder is pressed against the locking member. A pressing force can be applied to the movable platen, and the mold clamping cylinder is constituted by a double-acting cylinder having pressurizing chambers on both sides of the piston, and the first cylinder on the movable platen side The piston rod is caused to protrude by the hydraulic pressure applied to the pressurizing chamber, and the piston rod is caused to retract by the hydraulic pressure applied to the second pressurizing chamber on the pressure receiving plate side. A pressurizing chamber that is connected to the second pressurizing chamber and has a larger cross-sectional area than the second pressurizing chamber is connected to the pressure receiving plate side by the piston of the mold clamping cylinder. In preparation for this, a double-acting slave cylinder is built into the first pressurizing chamber of the mold clamping cylinder so that the piston rod can protrude by a predetermined length into the first pressurizing chamber of the mold clamping cylinder. These are respectively performed in conjunction with the retracting and protruding operations of the piston rod of the mold clamping cylinder.

(Operation/Effect) According to such a mold clamping device, the overall length of the main cylinder can be shortened compared to the direct pressure type, similar to the conventional hydromechanical mold clamping device described above.
Not only can the amount of hydraulic oil used be reduced, but also a locking member is provided directly on the pressure platen to prevent the distance rod installed on the movable platen from moving toward the pressure platen. It is possible to omit an intermediate strength member such as in a conventional hydromechanical mold clamping device, which makes the device simpler and easier to manufacture than a conventional hydromechanical mold clamping device. It can be improved.

Furthermore, according to the configuration of the mold clamping device according to the present invention,
The movement stroke of the piston rod of the mold clamping cylinder is reduced by providing a child cylinder on the piston of the mold clamping cylinder in such a manner that the piston rod can protrude by a predetermined distance into the first pressurizing chamber of the mold clamping cylinder. The size can be limited to the minimum necessary size, the accurate positioning of the distance rod can be tested, and the deadlock phenomenon when overfilling the mold cavity with resin material can be effectively prevented. .

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

First, in FIG. 1, 20 is a fixed mold 22.
This is a stationary plate to which the base 24 is attached, and is fixedly installed on the base 24. Further, in the figure, reference numeral 26 denotes a pressure receiving plate connected to the fixed platen 20 by a tie rod 28, and is disposed on the base 24 so as to be movable in the left and right directions in the figure. In addition, such pressure receiving plate 2
6 is a nut 36 screwed onto the tie rod 28.
is rotated by an electric motor 30 via a chain 32 and a sprocket 34, thereby moving toward and away from the stationary platen 20. Here, the electric motor 30, chain 32, sprocket 34, nut 36, etc. constitute a mechanism for moving the pressure receiving plate 26.

A movable platen 38 is provided between the fixed platen 20 and the pressure platen 26, and is guided by tie rods 28 to move in the left and right direction in FIG. Auxiliary cylinder 4
0,40 are arranged. And the movable plate 38
can be moved at high speed in the horizontal direction in the figure by these auxiliary cylinders 40, 40, and based on the movement of the movable platen 38 by the auxiliary cylinders 40, 40, the movable platen 38 is moved. The mold platen 42 provided thereon and the fixed mold 22 placed on the fixed platen 20 can be opened and closed at high speed.

On the back side of the movable platen 38 facing the pressure receiving platen 26, there are four mold clamping cylinders 4 (two of which are shown here) approximately equally spaced around the machine axis.
4 are provided. A distance rod 48 of a predetermined length is coaxially attached to one end of each of the piston rods 46 of the mold clamping cylinders 44 that protrude toward the pressure receiving plate 26 side.

On the other hand, the pressure receiving plate 26 is formed with four through holes 50 concentrically with the respective distance rods 48, which allow the distance rods 48 to be inserted therethrough. As shown in the figure, the pressure receiving plate 2 facing the movable plate 38
Two sets of locking devices 52, 52 are provided on the front surface of the device 6, corresponding to the two distance rods 48, respectively, to prevent the distance rods 48 from being inserted into the through holes 50. ing.

These lock devices 52, 52 each have a lock plate 54 as a lock member that is moved between a closed position in which two corresponding through holes 50 are simultaneously closed and an open position in which they are simultaneously opened.
, a guide member 56 for guiding the lock plate 54 between the closed position and the open position, and hydraulic pressure as a driving means for moving the lock plate 54 along the guide member 56 between the closed position and the open position. It consists of a cylinder 58.

Here, the lock plate 54 has a long rectangular plate shape that is long in the direction in which the two corresponding through holes 50 are arranged, and has a diameter larger than the distance rod 48 in the middle part in the longitudinal direction. diameter through hole 6
0 is formed. Further, the guide member 56 is
It has a U-shaped cross section, is fixed to the pressure receiving plate at both ends of the U-shaped portion, and guides the lock plate 54 in the longitudinal direction between the bottom wall of the U-shaped portion and the pressure receiving plate 26. I'm starting to do that. Furthermore, the hydraulic cylinder 58 is attached to the pressure receiving plate 26 parallel to the longitudinal direction of the lock plate 54, and is connected to an arm 64 extending from the lock plate 54 at the tip of its piston rod 62.

Here, guide holes 66, 66 of a predetermined length are formed in the lower wall portion of the guide member 56, into which each distance rod 48 is slidably fitted. When the piston rod 62 is retracted, the guide hole 66 of each corresponding guide member 56 and the through hole 50 of the pressure receiving plate 26 are shut off by the lock plate 54, while the hydraulic cylinder 58
When the piston rod 62 is operated to protrude, the lock plate 54 is removed from the position where it closes one of the through holes 50, and the rod plate 5
The four through holes 60 are moved to a position that coincides with the other through hole 50, so that the corresponding guide holes 66 and through holes 50 are brought into communication with each other.

In other words, the piston rod 6 of the hydraulic cylinder 58
2 is operated to protrude, the distance rod 48 and, by extension, the movable plate 38 move toward the pressure receiving plate 26 without being blocked by the lock plate 54, as shown in FIG. Conversely, when the piston rod 62 of the hydraulic cylinder 58 is retracted, the distance rod 48
Since the movable plate 38 comes into contact with the lock plate 54, movement of the movable plate 38 toward the pressure receiving plate 26 is prevented.

Therefore, according to this mold clamping device, the piston rod 62 of the hydraulic cylinder 58 of each locking device 52
When the auxiliary cylinder 40 is operated to protrude,
By operating the molds 22 and 24, the molds 22 and 24 can be opened and closed at high speed, and when the piston rod 62 of the hydraulic cylinder 58 of each locking device 52 is retracted, the piston rod of the mold clamping cylinder 44 can be opened and closed. 46 is projected and actuated, each distance rod 48 is brought into contact with the lock plate 54 of each locking device 52, and the pressing force based on the mold clamping cylinder 44 is applied as a reaction force to the movable platen 38, making it movable. Plate 38 and fixed plate 20
The clamping operation of the molds 22 and 42 can be performed between them.

In this case, there is no need to move the piston rod 46 of the mold clamping cylinder 44 relative to the main body of the mold clamping cylinder 44 during high-speed mold opening/closing operations of the molds 22, 42. Similar to the mold clamping device, the overall length of the mold clamping cylinder 44 can be made shorter than that of the direct pressure type, and the amount of hydraulic fluid used can be significantly reduced.

By the way, as shown in detail in FIG. 4, the mold clamping cylinder 44 includes a first pressurizing chamber 70 on the side of the movable plate 38 of the piston 68, and a first pressurizing chamber 70 on the side of the pressure receiving plate 26 of the piston 68. The piston rod 46 is a double-acting cylinder equipped with a second pressurizing chamber 72, and when hydraulic pressure is applied to the first pressurizing chamber 70, the piston rod 46 is operated to protrude toward the pressure receiving plate 26. In addition, when hydraulic pressure is applied to the second pressurizing chamber 72, the piston rod 46 is retracted toward the movable platen 38 side. Here, the piston 68 of the mold clamping cylinder 44 is
A child cylinder 76 is provided in such a manner that the piston rod 74 can protrude by a dimension S into the first pressurizing chamber 70 of the mold clamping cylinder 44. Based on the presence of this child cylinder 76, the mold clamping cylinder 44
The movement stroke of the piston 68 can be set to the minimum necessary size, and deadlock can be effectively prevented when the cavities of the molds 22, 42 are overfilled with resin material. There is.

That is, on the pressure receiving plate 26 side of the piston 78 of the child cylinder 76, there is a pressurizing member having a larger cross-sectional area than the second pressurizing chamber 72 of the mold clamping cylinder 44 and communicating with the second pressurizing chamber 72 of the mold clamping cylinder 44. A pressure chamber 80 is provided, and the second pressure chamber 7 of the mold clamping cylinder 44
2, so that when the piston rod 46 of the mold clamping cylinder 44 is retracted, the piston rod 74 of the child cylinder 76 is projected into the first pressurizing chamber 70 of the mold clamping cylinder 44. It's summery. The retracted position of the piston rod 46 of the mold clamping cylinder 44 is determined based on the fact that the piston rod 74 of the child cylinder 76 protruding toward the first pressurizing chamber 70 comes into contact with the cylinder wall on the movable platen 38 side. It's becoming like that.

On the other hand, the piston rod 4 on which hydraulic pressure is applied to the first pressurizing chamber 70 side of the mold clamping cylinder 44
6, as shown in FIG. 5, hydraulic pressure is applied to the pressurizing chamber 82 of the child cylinder 76 on the movable platen 38 side through the first pressurizing chamber 70. The piston rod 74 of the child cylinder 76 is retracted toward the pressure receiving plate 26. And with this,
Between the piston 68 of the mold clamping cylinder 44 and the cylinder wall on the movable platen 38 side of the first pressurizing chamber 70, there is a gap α larger than the actual movement stroke G of the piston 68 by the dimension S. As will be described later, such a gap: α (here, strictly speaking, the gap between the piston rod 74 of the child cylinder 76 and the cylinder wall:
Due to the presence of β), deadlock is effectively prevented when the cavity is overfilled with resin material.

In such a mold clamping device, before a normal mold clamping operation, the pressure receiving plate 26 is first moved by the electric motor 30, and the molds 22, 4 are moved as shown in FIG.
2, each distance rod 4
8 and the lock plate 54 of each lock device 52 so that a predetermined gap G is formed between the lock plate 54 of each lock device 52,
The pressure receiving plate 26 performs positioning. After the pressure receiving plate 26 is positioned, a normal mold clamping operation is performed. Note that the gap G corresponds to the movement stroke G of the piston 68 of the mold clamping cylinder 44, so in order to shorten the molding cycle, it should be made as narrow as possible within the range that allows smooth movement of the lock plate 54. Set it small.

By the way, in the mold clamping device, the pressure receiving plate 2
6, the piston rod 62 of the hydraulic cylinder 58 of each locking device 52 is moved as described above.
Under the protruding operating condition of the auxiliary cylinder 40,
40 is activated to perform high-speed mold opening/closing operations of the molds 22, 42, while the piston rods 4 of each mold clamping cylinder 44 are in a retracting state of the piston rods 62 of the hydraulic cylinders 58.
6 is operated to protrude, the molds 22, 42 are clamped, and thereby the molds 22, 24
When the molds 22, 42 are opened and closed at high speed by the auxiliary cylinders 40, 40, the hydraulic pressure is applied to the second pressurizing chamber 72 of each mold clamping cylinder 44. Let it work.

In this way, as described above, the piston rod 46 is held in the retracted position where the piston rod 74 of the child cylinder 76 contacts the cylinder wall, and the molds 22, 42 are opened and closed at high speed. As shown in FIG. 4, when the molds 22 and 42 are closed, the gap G is formed between each distance rod 48 and the lock plate 54 of each lock device 52. At the same time, the gap S is formed between the piston 68 of the mold clamping cylinder 44 and the cylinder wall on the movable platen 38 side.

Therefore, if the piston rod 46 of the mold clamping cylinder 44 is operated to protrude from this state and the distance rod 48 is brought into contact with the lock plate 54 to press the molds 22, 42, the piston of the mold clamping cylinder 44 will be moved. The gap α(=S+G) is formed between the movable platen 38 and the cylinder wall, and when the cavities of the molds 22 and 42 are overfilled with resin material, the gap α( in fact,
Based on the existence of the gap (β), it is moved toward the pressure receiving plate 26, and deadlock can be effectively avoided.

In addition, the movable platen 3 due to overfilling of such resin material
8 is allowed to move because the hydraulic oil in the first pressurizing chamber 70 of the mold clamping cylinder 44 is discharged through the relief valve 84, as shown in FIG. In addition, the gap β for preventing the above-mentioned deadlock can be set to any size, but in general, as shown in Fig. 6, the maximum injection amount of resin material is Even if the piston rod 7 of the child cylinder 76
The size is set such that a predetermined gap: γ is formed between 4 and the cylinder wall.

As explained above, according to the mold clamping device of this embodiment, the overall length of the main cylinder can be shortened compared to the direct pressure type, similar to the conventional hydromechanical mold clamping device, and the amount of hydraulic oil used can be reduced. Moreover, such an effect can be obtained without using an intermediate strength member such as an intermediate pressure receiving plate of a conventional hydromechanical mold clamping device. Therefore, it has the same function as the conventional hydromechanical mold clamping device.
This can be advantageously achieved with a simple structure that is easier to manufacture.

Further, according to the mold clamping device of this embodiment, a double-acting cylinder with a built-in child cylinder 76 is adopted as the mold clamping cylinder 44, and the piston rod 46 of the mold clamping cylinder 44 can be moved into the cavity without increasing the movement stroke. Since deadlock can be effectively avoided when overfilling the resin material, the operating time of the mold clamping cylinder 44 can be advantageously shortened, thereby advantageously shortening the mold clamping cycle and, by extension, the injection molding cycle. There are also some advantages.

Furthermore, in this embodiment, there are four mold clamping cylinders 4.
Since the mold clamping cylinders 44 are arranged at equal intervals around the machine axis, the ejector mechanism 86 can be installed in the center of the mold clamping cylinders 44 without any problem, as shown in FIG. There are also advantages.

Although one embodiment of the present invention has been described in detail above,
These are literal examples, and it goes without saying that the present invention is not limited to these specific examples, and can be implemented with various changes, modifications, improvements, etc., without departing from the spirit thereof. be.

For example, in the above embodiment, four mold clamping cylinders 44 are arranged at equal intervals around the machine axis, but the arrangement form and arrangement of the mold clamping cylinders 44 are as follows.
It is possible to make appropriate changes as necessary, and it is also possible to adopt a single-acting cylinder structure as the mold clamping cylinder 44.

Further, as a locking device for preventing the distance rod 48 from being inserted into the through hole 50 of the pressure receiving plate 26, a rotating type device is adopted in which a locking plate serving as a locking member is rotated around a single axis. It is possible to connect the pressure receiving plate 26 to the fixed plate 2.
As a moving mechanism for moving toward and away from zero, it is possible to employ various structures.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of a main part showing an example of a mold clamping device according to the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. It is a partial sectional view showing a form. Figure 4 shows
5 is an explanatory cross-sectional view showing an enlarged main part of the mold clamping device in FIG. 1, and FIG. 5 and FIG. 6 each correspond to a part of FIG. 4 in a different operating mode from FIG. 4; FIG. FIG. 7 is an explanatory sectional view showing a conventional example. 20: Fixed plate, 22: Fixed mold, 26: Pressure receiving plate, 28: Tie rod, 38: Movable plate, 40: Auxiliary cylinder, 42: Movable mold, 44: Mold clamping cylinder, 46: Piston rod (mold clamping cylinder) ),
48: Distance rod, 50: Through hole, 5
2: Lock device, 54: Lock plate (lock member), 56: Guide member, 58: Hydraulic cylinder (driving means), 60: Through hole, 66: Guide hole, 6
8: Piston (of the mold clamping cylinder), 70: First pressurizing chamber, 72: Second pressurizing chamber, 74: Piston rod (of the child cylinder), 76: Child cylinder, 7
8: Piston (of child cylinder).

Claims (1)

[Scope of Claims] 1. A movable plate is disposed between a fixed plate and a pressure receiving plate connected by tie rods, and an auxiliary cylinder provided between the movable plate and the pressure receiving plate is used to control the movable plate. The mold is opened and closed between the movable plate and the fixed plate by moving the movable plate close to and melting the fixed plate. In a mold clamping device for an injection molding machine, the mold is clamped between a movable platen and a fixed platen by applying pressure with a mold clamping cylinder, wherein the plurality of mold clamping cylinders are connected to the pressure receiving Disposed on the back side of the movable platen facing the platen, and provided with a distance rod of a predetermined length so as to extend from each piston rod of the mold clamping cylinders toward the pressure receiving plate; A through hole is formed to allow the insertion of the distance rod, and when the movable platen is brought close to the pressure receiving plate by the auxiliary cylinder, the distance rod is inserted into the through hole. At the same time, a predetermined driving means is provided for the pressure receiving plate to selectively set the distance rod at a position that allows insertion into the through hole and a position that prevents such insertion. A lock member is provided that can be moved to the lock member, and when the lock member prevents insertion of the distance rod, the piston rod of the mold clamping cylinder is operated to project, so that the distance rod is brought into contact with the lock member. Let me touch you,
A pressing force based on the mold clamping cylinder can be applied to the movable platen, and the mold clamping cylinder is constituted by a double-acting cylinder having pressurizing chambers on both sides of its piston, so that the movable The hydraulic pressure applied to the first pressurizing chamber on the side of the pressure plate causes the piston rod to protrude, and the hydraulic pressure applied to the second pressurized chamber on the pressure receiving plate causes the piston rod to protrude. is adapted to be retracted, and the piston of the mold clamping cylinder is communicated with the second pressurizing chamber,
A pressure chamber having a larger cross-sectional area than the second pressure chamber is provided on the pressure receiving plate side, and the piston rod is disposed so as to be able to protrude by a predetermined distance into the first pressure chamber of the mold clamping cylinder. A movable child cylinder is built in, so that the protruding and retracting operations of the piston rod of the child cylinder are performed in conjunction with the retracting and protruding operations of the piston rod of the mold clamping cylinder, respectively. A mold clamping device for an injection molding machine characterized by the following. 2. The mold clamping device according to claim 1, wherein the pressure receiving plate can be moved toward and away from the fixed plate by a predetermined moving mechanism.