JPH0631426A - Die clamping device - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the mold clamping balance. [Structure] The mold clamping device according to the present invention includes a tie bar 106.
And a mold moving hydraulic cylinder 114 that moves the movable mold 124 to a position where the movable mold 124 is engaged with the fixed mold 104 while pressing the movable plate 120, and is coaxially arranged between the mold clamping ram 112 and the movable mold 124. The hydraulic cylinder 130 for pressure transmission is provided. Further, hydraulic circuits Y1 and Y2 are provided between the mold moving hydraulic cylinder 114 and the pressure transmitting hydraulic cylinder 130 so that hydraulic oil can be exchanged. A check valve 142 is provided in the mold clamping side oil chamber 130a of the pressure transmitting hydraulic cylinder 130. During mold clamping, the pressing force of the mold clamping ram 112 is applied to the center of the movable plate 120 via the pressure transmitting hydraulic cylinder 130. Further, the pressing force from the die moving hydraulic cylinder 114 is applied to the four corners of the movable plate 120. Therefore, the mold clamping balance is improved. Further, the mold moving hydraulic cylinder 114 and the pressure transmitting hydraulic cylinder 130.
Since hydraulic fluid can be exchanged with the hydraulic fluid, the amount of hydraulic fluid is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies a pressing force of a mold clamping ram to a movable die while the movable die is moved along a plurality of tie bars and the movable die is engaged with a fixed die. The present invention relates to a mold clamping device that performs mold clamping.

[0002]

2. Description of the Related Art A technique related to this is disclosed in Japanese Patent Laid-Open No. 3-230.
No. 49, the longitudinal sectional view of an injection molding machine equipped with this mold clamping device is shown in FIG. 7 attached to the application of the present application. This injection molding machine includes a fixed plate 11 fixed to a base (not shown), and a fixed mold 12 is attached to the fixed plate 11. Further, one end of a cylindrical tie bar 29 is fixed to each of the four corners of the stationary platen 11, and the other ends of these tie bars 29 are connected to a plate for fixing the mold clamping cylinder 16. The fixed plate 11 and the mold clamping cylinder 1
The movable platen 13 is connected between the movable plate 13 and the tie bar 29 so as to be movable along the tie bar 29. In this movable platen 13,
A movable mold 14 is attached to a surface facing the fixed platen 11, and the movable mold 14 can be engaged with the fixed mold 12. Further, on the surface of the movable plate 13 facing the mold clamping cylinder 16, the connecting shaft 1 having a collar 22 at the tip thereof is provided.
5 is fixed.

On the other hand, the die clamping cylinder 16 is provided with a ram 19 which moves in the axial direction of the die clamping cylinder 16 by hydraulic pressure, and a cavity 21 is formed inside the ram 19. The hollow portion 21 is provided with a step portion 20 at the inlet, and the inlet portion is narrower than the other portions. The connecting shaft 1 is inserted into the hollow portion 21.
5 is housed so that the stepped portion 20 of the hollow portion 21 and the flange 22 of the connecting shaft 15 can be engaged with each other. The ram 19
A lock plate 23 is attached to the front end of the hollow plate 21 so as to be movable in a direction perpendicular to the center line of the cavity 21. This lock plate 23 moves to move the ram 19
Crossing over, the collar 22 of the connecting shaft 15 is sandwiched by the lock plate 23 and the step portion 20 of the hollow portion 21 of the ram 19. As a result, the ram 19 and the connecting shaft 15 are connected so that they cannot move relative to each other. Also, when the lock plate 23 moves in the lateral direction of the ram 19 and comes off the tip of the connecting shaft 15, the connecting shaft 15 can enter the cavity 21 of the ram 19. A mold moving cylinder 25 for moving the movable platen 13 is provided on a side surface of a plate for fixing the mold clamping cylinder 16.
Is fixed.

In order to perform mold clamping of this injection molding machine, first, the mold moving cylinder 25 is driven in the direction in which the piston rod 26 thereof is extended, and the movable mold 14 is engaged with the fixed mold 12. To combine. Here, when the movable mold 14 engages with the fixed mold 12, the collar 22 of the connecting shaft 15 causes the cavity 2 to move.
The stepped portion 20 of No. 1 is engaged. Lock plate 2 in this state
3 is moved to sandwich the collar 22 of the connecting shaft 15 between the lock plate 23 and the step portion 20 of the hollow portion 21 of the ram 19. As a result, the ram 19 and the connecting shaft 15 are connected so that they cannot move relative to each other. Next, the mold clamping cylinder 16
Is operated to press the movable mold 14 by the ram 19 and the connecting shaft 15 to clamp the mold. Further, in order to open the mold of the injection molding machine, first, the pressure of the mold clamping cylinder 16 is released, and the lock plate 23 is moved in a direction away from the connecting shaft 15. Accordingly, the connecting shaft 15
Can enter the cavity 21 of the ram 19. In this state, the mold moving cylinder 25 is driven in the direction in which the piston rod 26 is stored, and the movable platen 13 is separated from the fixed platen 11 to open the mold.

As described above, according to the conventional mold clamping device, since the ram 19 of the mold clamping cylinder 16 has the hollow portion 21, only a distance corresponding to the length of the hollow portion 21 in the axial direction is provided. The working stroke of the mold clamping cylinder 16 can be made smaller than the working stroke of the mold moving cylinder 25. Therefore, the working oil of the mold clamping cylinder 16 can be reduced by an amount corresponding to the length of the cavity 21 of the ram 19, and the hydraulic pump, the oil tank, etc. can be downsized, and the equipment cost can be reduced.

[0006]

However, according to the above-described conventional mold clamping device, the movable platen 13 is used at the time of mold clamping.
The pressing force of the ram 19 is applied to the center of the movable plate 13, and the pressing force of the die moving cylinder 25 is applied to one end of the movable platen 13. For this reason, imbalance in mold clamping may occur, which may cause burr blowing or the like. Further, due to the structure in which the lock plate 23 is inserted between the ram 19 and the connecting shaft 15 to connect the ram 19 and the connecting shaft 15, the pressing force of the ram 19 is directly applied to the lock plate 23. Lock plate 23
Has the drawback that it is easily deformed. Therefore, a trouble may occur due to the lock plate 23 being caught. A technical problem of the present invention is to install a hydraulic cylinder for moving a mold at the position of each tie bar to prevent burrs from being blown by uniformly pressing a movable mold during mold clamping. Further, a hydraulic cylinder for pressure transmission is installed between the mold clamping ram and the movable mold to eliminate the need for the conventional lock plate, thereby improving the reliability of the mold clamping device.

[0007]

The above-mentioned problems can be solved by a mold clamping device having the following respective structures. That is, in the mold clamping device according to claim 1, the movable mold is moved along the plurality of tie bars, and the pressing force of the mold clamping ram is applied to the movable mold while the movable mold is engaged with the fixed mold. In the mold clamping device for performing mold clamping by adding, a mold moving hydraulic cylinder that is installed on each of the tie bars and moves the movable mold to a position where the movable mold is engaged with the fixed mold while pressing the movable mold. And a mold clamping hydraulic cylinder for operating the mold clamping ram, and a coaxial cylinder disposed between the mold clamping ram and the movable mold, in response to an increase in the distance between the mold clamping ram and the movable mold. Hydraulic cylinder for extending the piston rod and the hydraulic oil flowing out of the hydraulic cylinder for moving the die to the inlet of the hydraulic cylinder for pressure transmitting, and hydraulic oil flowing out of the hydraulic cylinder for pressure transmitting. To A hydraulic circuit configured to be guided to the inlet of the hydraulic cylinder for moving the mold, and a lock mechanism installed in the hydraulic circuit for inhibiting the outflow of hydraulic oil from the hydraulic cylinder for pressure transmission during mold clamping. have. A mold clamping device according to a second aspect is the mold clamping device according to the first aspect, wherein the pressure transmitting hydraulic cylinder with respect to the movable die is provided between the pressure transmitting hydraulic cylinder and the movable die. A position adjusting hydraulic cylinder for adjusting the position of is arranged. A mold clamping device according to a third aspect is the mold clamping device according to the first aspect, further comprising position detecting means for detecting a position of the mold clamping ram,
Positioning means for storing the position of the mold clamping ram at the time of mold clamping, and operation stopping means for stopping the operation of the mold clamping hydraulic cylinder when the mold clamping ram moves a predetermined distance from the mold clamping position are provided. is doing.

[0008]

According to the mold clamping device of the first aspect, when the movable mold moves to the position where the movable mold engages with the fixed mold, and the distance between the mold clamping ram and the movable mold increases, the pressure is transmitted by the increased distance. Hydraulic cylinder extends the piston rod. The pressure transmitting hydraulic cylinder is held in a state in which the piston rod is extended by a predetermined length by the lock mechanism working during mold clamping. By operating the mold clamping hydraulic cylinder in this state, the pressing force of the mold clamping ram is transmitted to the movable mold via the pressure transmitting hydraulic cylinder to perform mold clamping. Further, since the pressing force of the hydraulic cylinders for moving the mold installed on each tie bar is applied to the end portion of the movable mold in good balance during mold clamping, the mold clamping balance becomes good. Further, during the operation of the die moving hydraulic cylinder and the pressure transmitting hydraulic cylinder, hydraulic fluid is exchanged between the die moving hydraulic cylinder and the pressure transmitting hydraulic cylinder by the hydraulic circuit, so that these new oils are externally supplied. A small amount of hydraulic oil is supplied to the die moving hydraulic cylinder and the pressure transmitting hydraulic cylinder. Further, since there is no member corresponding to the conventional lock plate, the reliability of the mold clamping device is improved. According to the mold clamping device of the second aspect, the position adjusting hydraulic cylinder for adjusting the position of the pressure transmitting hydraulic cylinder with respect to the movable die is disposed between the pressure transmitting hydraulic cylinder and the movable die. There is. Therefore, even if the thickness of the mold is changed by exchanging the movable mold and the fixed mold (mold), the position adjustment hydraulic cylinder can absorb the change in the thickness. Therefore, it is not necessary to absorb the change in the mold thickness by the mold clamping hydraulic cylinder, and the operating stroke length of the mold clamping hydraulic cylinder can be set to the minimum value required for mold clamping. According to the mold clamping device of claim 3, the position storing means can store the position (mold clamping position) of the mold clamping ram at the time of mold clamping, and when the mold is opened, the mold clamping ram is a predetermined distance from the mold clamping position. When moved, the mold clamping hydraulic cylinder is stopped by the operation stopping means. For this reason, the mold clamping hydraulic cylinder can be operated within a necessary minimum range, and the amount of hydraulic oil used in the mold clamping hydraulic cylinder is reduced. Also, the time required for mold opening is shortened.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mold clamping device according to a first embodiment of the present invention will be described below with reference to FIGS. The present embodiment is an application of the mold clamping device according to the present invention to a die casting machine 100. FIG. 1 is a front view of a main part of the die casting machine 100 in a mold clamped state, and FIG. 2 is a die cast in a mold opened state. FIG. 3 is a front view of a main part of the machine 100. The die casting machine 100 includes a fixed plate 102 fixed to a base (not shown), and a fixed mold 104 is mounted on the fixed plate 102. At the four corners of the fixed plate 102, the lower ends of tie bars 106, which are columnar columns, are fixed, and the upper ends of these tie bars 106 are fixed to the upper plate 108. As a result, the upper plate 108 is supported in a state where it cannot move relative to the fixed plate 102. Further, a collar portion (hereinafter referred to as piston 106a) that functions as a piston 106a of a die moving hydraulic cylinder 114, which will be described later, is formed in the central portion of the four tie bars 106.
At the center of the upper plate 108, a mold clamping hydraulic cylinder 110 positioned so that its axis is parallel to the tie bar 106 is installed. The mold clamping hydraulic cylinder 110 is formed with a mold clamping side oil chamber 110a and a return side oil chamber 110b which are divided by the upper piston portion 112a of the mold clamping ram 112, and each oil chamber 1
Hydraulic pipes (not shown) are connected to 10a and 110b. The area of the upper surface of the upper piston portion 112a (on the mold clamping side oil chamber 110a side) is set to S0.

A movable plate 120 is arranged between the upper plate 108 and the fixed plate 102 so that it can be moved up and down along the tie bar 106. A movable mold 124 that engages with the fixed mold 104 is attached to the lower surface 120b of the movable plate 120. A cavity is formed inside when the movable mold 124 and the fixed mold 104 are engaged with each other. A pressure transmission hydraulic cylinder 130 is installed on the upper surface 120a of the movable plate 120 with its center line aligned with the die clamping hydraulic cylinder 110. The pressure transmission hydraulic cylinder 130 has the mold clamping ram. A lower piston portion 112b formed at the tip of 112 is slidably accommodated. Here, the area of the tip surface (lower end surface) of the lower piston portion 112b is set to S3, and the area of the upper end surface is S3.
It is set to 2. In the pressure transmitting hydraulic cylinder 130, the lower side of the lower piston portion 112b functions as the mold clamping side oil chamber 130a, and the lower piston portion 11b
The upper side of 2b functions as the return side oil chamber 130b.

Further, the upper surface 12 of the movable plate 120.
At 0a, hydraulic cylinders 114 for moving the mold are installed at the four corners. Then, in the die moving hydraulic cylinder 114,
The piston 106a formed on the tie bar 106 is slidably accommodated. And this piston 106
The lower side of a functions as the mold clamping side oil chamber 114a, and the upper side of the piston 106a functions as the return side oil chamber 114b. The area of the upper end surface and the lower end surface of the piston 106a is set to S1. The mold clamping side oil chambers 114a formed in the mold moving hydraulic cylinders 114 communicate with each other through hydraulic pipes Y1. The mold clamping side oil chamber 114a is provided with the pressure transmitting hydraulic cylinder 13.
The return side oil chamber 130b of 0 is communicated with the hydraulic pipe Y1. Further, the respective return-side oil chambers 114b formed in the die moving hydraulic cylinder 114 are communicated with each other by a hydraulic pipe Y2. The return side oil chamber 114b is the mold clamping side oil chamber 130a of the pressure transmitting hydraulic cylinder 130.
To the hydraulic pipe Y2 via a check valve 142. The check valve 142 is attached so that the hydraulic oil can flow into the mold clamping side oil chamber 130a of the pressure transmitting hydraulic cylinder 130, and blocks the reverse flow of the hydraulic oil. That is, the check valve 142 acts as a lock mechanism. Here, the hydraulic pipes Y1 and Y2 are electromagnetic valves 1
By 44, connection can be changed to the hydraulic pressure source 140 side or the oil tank 146 side. The total pressure receiving area 4 × S1 of the four pistons 106a of the die moving hydraulic cylinder 114 is equal to the area S2 of the upper end surface of the lower piston portion 112b housed in the pressure transmitting hydraulic cylinder 130.
And is set to be larger than the area S3 of the tip surface.

For example, as shown in FIG. 1, a solenoid valve 144
When the hydraulic pipe Y1 is connected to the hydraulic source 140 and the hydraulic pipe Y2 is connected to the oil tank 146 by the above, when the maximum pressure of the hydraulic source 140 is P0 and the hydraulic pressure during the mold clamping operation is P1, the mold moving hydraulic cylinder Clamping side oil chamber 114
The hydraulic pressure P1 acts on a, and at the same time, the hydraulic pressure P1 acts on the return side oil chamber 130b of the pressure transmitting hydraulic cylinder 130. Here, as described above, the total area 4 × S1 of the piston 106a of the die moving hydraulic cylinder 114 is set larger than the area S2 of the lower piston portion 112b of the pressure transmitting hydraulic cylinder 130. Therefore, the force (P1 × 4 × S1) for the die moving hydraulic cylinder 114 to lower the movable plate 120 is the pressure transmitting hydraulic cylinder 13.
0 is the force (P1
XS2), the movable plate 120 is
It receives the force of F1 = P1 × (4 × S1-S2) and moves down following the tie bar 106. As a result, the hydraulic oil flows out of the return side oil chamber 130b of the pressure transmitting hydraulic cylinder 130 despite the fact that the hydraulic pressure P1 is applied, and the mold clamping side oil chamber 114a of the mold moving hydraulic cylinder 114.
The hydraulic oil flows into the. Furthermore, hydraulic cylinder 1 for mold movement
The hydraulic oil flows out of the return-side oil chamber 114b of 14, and the hydraulic oil flows into the mold clamping side oil chamber 130a of the pressure transmitting hydraulic cylinder 130. Here, the hydraulic cylinder 13 for pressure transmission
0 return side oil chamber 130b and die moving hydraulic cylinder 114
Is connected to the mold clamping side oil chamber 114a by a hydraulic pipe Y1, and the mold clamping side oil chamber 130a of the pressure transmitting hydraulic cylinder 130 and the return side oil chamber 114b of the mold moving hydraulic cylinder 114 are hydraulic pipe Y2. Are in communication with each other.
Therefore, the hydraulic oil moves between the hydraulic cylinders 114 and 130, and the shortage of hydraulic oil is supplied from the hydraulic pressure source 140. Further, the surplus of hydraulic oil is returned to the oil tank 146.

Further, as shown in FIG. 2, when the hydraulic pipe Y2 is connected to the hydraulic pressure source 140 by the solenoid valve 144 and the hydraulic pipe Y1 is connected to the oil tank 146, the hydraulic pressure during the mold opening operation is P2. Hydraulic cylinder 1 for mold movement, if any
The hydraulic pressure P2 acts on the return side oil chamber 114b of the hydraulic pressure control hydraulic cylinder 130, and at the same time, the mold clamping side oil chamber 130a of the hydraulic cylinder 130 for pressure transmission.
The hydraulic pressure P2 acts on. Therefore, pressure is applied to the check valve 142 provided in the hydraulic pipe Y2 through the pilot line 142p, and the check valve 142 is held in the open state. As described above, since the total area 4 × S1 of the piston 106a of the die moving hydraulic cylinder 114 is larger than the area S3 of the lower piston portion 112b of the pressure transmitting hydraulic cylinder 130, the movable plate 120 has F2 = P2.
The tie bar 106 receives a force of × (4 × S1-S3).
Rises following. As a result, the hydraulic oil flows out from the mold clamping side oil chamber 130a of the pressure transmitting hydraulic cylinder 130 regardless of the fact that the hydraulic pressure P2 is applied, and also to the return side oil chamber 114b of the die moving hydraulic cylinder 114. Hydraulic fluid flows in. Further, the working oil flows out from the mold clamping side oil chamber 114a of the mold moving hydraulic cylinder 114, and the working oil flows into the return side oil chamber 130b of the pressure transmitting hydraulic cylinder 130. In this way, the hydraulic oil is supplied to both hydraulic cylinders 114,
After moving between 130, the shortage of hydraulic oil is supplied from the hydraulic pressure source 140, and the surplus is returned to the oil tank 146.

Next, in the die casting machine 100,
A method of clamping the mold after replacing the molds 104 and 124 and further opening the mold will be described. First, as shown in FIG. 2, in the mold opening state, hydraulic pressure is applied to the return side oil chamber 110b of the mold clamping hydraulic cylinder 110 to raise the mold clamping ram 112 to move the movable plate 120 to the uppermost limit. Hold on. In this state, the fixed mold 104 and the movable mold 124 are set on the fixed plate 102 by a mold exchanging device (not shown). When the setting of the fixed mold 104 and the movable mold 124 is completed, the solenoid valve 144 is operated and the hydraulic pipe Y1 is connected to the hydraulic source 1 as shown in FIG.
40, and the hydraulic pipe Y2 is connected to the oil tank 146. As a result, the hydraulic pressure P1 acts on the mold clamping side oil chamber 114a of the mold moving hydraulic cylinder 114 and the return side oil chamber 130b of the pressure transmitting hydraulic cylinder 130, and the movable plate 120 is directed downward F1 = P1 × (4 × S1 In response to the force of -S2), it follows the tie bar 106 and descends. At the position where the lower surface 120b of the movable plate 120 contacts the movable mold 124, the lowering of the movable plate 120 stops,
The movable plate 120 receives a downward force F1 = P1 × (4 × S1-S2) by the hydraulic cylinder 114 for moving the die. Further, in order to deal with slight variations in the thickness of the molds 104 and 124, even when the lower surface 120b of the movable plate 120 is in contact with the movable mold 124, the strokes of the mold moving hydraulic cylinder 114 and the pressure transmitting hydraulic cylinder 130. Has some leeway. The pressure of the hydraulic source 140 is P0 when the die moving hydraulic cylinder 114 and the pressure transmitting hydraulic cylinder 130 are stopped.

Next, the hydraulic pressure P0 acts on the mold clamping side oil chamber 110a of the mold clamping hydraulic cylinder 110 to cause the mold clamping ram 11 to move.
2 descends. In this state, the movable mold 124 is fixed to the movable plate 120 with a die clamper or the like (not shown), and the mounting of the molds 104 and 124 is completed. Here, since the hydraulic pressure P0 continues to act on the mold clamping side oil chamber 110a of the mold clamping hydraulic cylinder 110, a downward force Fr = P0 × S0 is applied to the mold clamping ram 112. However, the hydraulic cylinder 13 for pressure transmission
Since the check valve 142 prevents the hydraulic fluid from flowing out of the mold clamping side oil chamber 130a, the hydraulic pressure rises inside the mold clamping side oil chamber 130a. The state in which the hydraulic pressure reaches the predetermined hydraulic pressure P3 inside the mold clamping side oil chamber 130a, that is, the pressing force Fr = P0 × S0 of the mold clamping ram,
The lowering of the mold clamping ram 112 is stopped in a state where the force supporting the mold clamping ram 112 from below is equal to P3 × S3. In this state, the movable plate 120 and the movable mold 124 are
The pressing force Fr = P0 × S0 of the mold clamping ram is transmitted to.

In this way, the movable plate 120 has
A pressing force F1 = P0 × (4 × S1−S2) is applied from the die moving hydraulic cylinders 114 located at the four corners, and a pressing force Fr = P0 × is further applied from the die clamping ram 112 to the central portion.
S0 is added to achieve a well-balanced mold clamping.
Further, as described above, the pressing force Fr = of the mold clamping ram 112 is
P0 × S0 is the force P3 that supports the mold clamping ram 112 from below.
Since it is equal to × S3, the pressure transmission hydraulic cylinder 130 can be miniaturized by increasing P3 within a permissible range and decreasing the tip area S3 of the lower piston portion 112b. Further, when the strokes of the mold moving hydraulic cylinder 114 and the pressure transmitting hydraulic cylinder 130 are allowed to have some allowance for slight variations in the thickness of the molds 104 and 124, the large-diameter mold clamping hydraulic cylinder 110 is used.
The stroke is required to be the stroke required to compress the hydraulic oil in the mold clamping side oil chamber 130a of the pressure transmitting hydraulic cylinder 130, and a very small amount of hydraulic oil can be used.

When the mold clamping is completed, the molds 124, 104
The molten metal is pressed into the inside at high speed to perform casting. When a predetermined cooling time elapses, as shown in FIG. 2, the solenoid valve 144 operates to connect the hydraulic pipe Y2 to the hydraulic source 140, and the hydraulic pipe Y1 to the oil tank 146.
As a result, the mold opening hydraulic pressure P2 acts on the return side oil chamber 114b of the mold moving hydraulic cylinder 114 and the mold clamping side oil chamber 130a of the pressure transmitting hydraulic cylinder 130. Further, hydraulic pressure acts on the return side oil chamber 110b of the mold clamping hydraulic cylinder 110. This allows the movable plate 120 to
Lifting force by the hydraulic cylinder 114 for moving the mold F2 =
P2 * (4 * S1-S3) is added. If the pulling force F2 is sufficiently larger than the mold release resistance, the movable plate 120 rises and the mold opening is performed. If the pulling force F2 is smaller than the mold release resistance, the lower piston portion 112b of the mold clamping ram 112 pulls the pressure transmitting hydraulic cylinder 130 upward to release the mold, and then the movable plate 114 is moved by the mold moving hydraulic cylinder 114. 120 rises and the mold opening is performed.

As described above, according to this embodiment, the die moving hydraulic cylinders 114 press the four corners of the movable plate 120, and the die clamping ram 112 presses the central portion of the movable plate 120 to perform die clamping. In addition, the mold clamping balance is improved. Therefore, it is possible to prevent burrs from blowing. Further, while the die moving hydraulic cylinder 114 and the pressure transmitting hydraulic cylinder 130 are operating, the hydraulic circuit Y
Since hydraulic oil is exchanged between the die moving hydraulic cylinder 114 and the pressure transmitting hydraulic cylinder 130 by means of 1 and Y2, these hydraulic cylinders 11 are newly added from the outside.
A small amount of hydraulic oil is supplied to 4,130, and hydraulic equipment such as an oil pump, an oil tank, and hydraulic piping can be downsized.
Further, if the stroke of the pressure transmitting hydraulic cylinder 130 is allowed to have a slight allowance, the molds 104, 12 are caused by thermal expansion or the like.
Even if the thickness of 4 changes, the hydraulic cylinder 130 for pressure transmission
Can be dealt with by changing the stroke, and the hydraulic cylinder 110 for mold clamping can always cope with the minimum stroke required for constant mold clamping.

Next, a mold clamping device according to a second embodiment of the present invention will be described with reference to FIGS. This embodiment is an application of the mold clamping device according to the present invention to a die casting machine 200. FIG. 3 is a front view of a main part of the die casting machine 200 in a mold clamped state, and FIG. 4 is a die cast in a mold opened state. 3 is a front view of a main part of the machine 200. FIG. The mold clamping device according to the present embodiment is provided with a die height adjusting hydraulic cylinder between the pressure transmitting hydraulic cylinder 130 and the movable plate 120 of the mold clamping device according to the first embodiment, and further includes the pressure transmitting hydraulic cylinder 130. The hydraulic circuit for connecting to the mold moving hydraulic cylinder 114 is improved, and other structures are similar to those of the mold clamping device according to the first embodiment. At the center of the upper plate 208, a mold clamping hydraulic cylinder 210 positioned so that its axis is parallel to the tie bar 206 is installed. The mold clamping hydraulic cylinder 210 includes a mold clamping side oil chamber 210 divided by an upper piston portion 212a of a mold clamping ram 212.
a and a return side oil chamber 210b are formed, and a hydraulic pipe (not shown) is connected to each of the oil chambers 210a and 210b. The upper piston portion 212a
The area of the upper surface (the mold clamping side oil chamber 210a side) is set to S0. A lower piston portion 212b is formed at the tip (lower end) of the mold clamping ram 212, and a planar circular recess 212c is formed in the central axial direction of the lower piston portion 212b. The tip of this mold clamping ram 212 is the hydraulic cylinder 230 for pressure transmission.
It is slidably housed inside. Here, the tip end surface (lower end surface) of the lower piston portion 212b and the recess 212
The total area of the seating surfaces of c is set to S3, and the area of the upper end surface is set to S2. In the pressure transmitting hydraulic cylinder 230, the lower piston portion 212
The lower side of b functions as the mold clamping side oil chamber 230a, and the upper side of the lower piston portion 212b functions as the return side oil chamber 230b. A flange-shaped piston portion 230p is formed at the lower end of the pressure transmitting hydraulic cylinder 230.

On the other hand, the upper surface 220a of the movable plate 220
, A die height adjusting hydraulic cylinder 250 is installed with its center lines aligned with the mold clamping hydraulic cylinder 210 and the pressure transmitting hydraulic cylinder 230. The piston portion 230p of the pressure transmitting hydraulic cylinder 230 is slidably housed inside the die height adjusting hydraulic cylinder 250. As a result, the inside of the die height adjusting hydraulic cylinder 250 is divided into the mold clamping side oil chamber 250a and the returning side oil chamber 250b by the piston portion 230p of the pressure transmitting hydraulic cylinder 230. That is, the die height adjusting hydraulic cylinder 250 acts as a position adjusting hydraulic cylinder. In addition, the hydraulic cylinder for die height adjustment 250 has a hydraulic oil pipe 230c at the inner center.
Are installed coaxially. This hydraulic oil pipe 230c is provided on the mold clamping side oil chamber 2 of the hydraulic cylinder 230 for pressure transmission from the outside.
30a is a pipe for supplying hydraulic oil, and a through hole 230 formed in the bottom of the hydraulic cylinder 230 for pressure transmission.
It is slidably inserted in k. Furthermore, the outer diameter of the hydraulic oil pipe 230c is made smaller than the inner diameter of the recess 212c formed at the tip of the mold clamping ram 212. Therefore, even if the die height adjusting hydraulic cylinder 250 approaches the mold clamping ram 212,
The tip (upper end) of the hydraulic oil pipe 230c does not contact the lower piston portion 212b of 12 and the hydraulic oil pipe 230c can smoothly enter the recess 212c of the mold clamping ram 212. An O-ring (not shown) is provided between the hydraulic oil pipe 230c and the through hole 230k, and the mold clamping side oil chamber 23 of the pressure transmitting hydraulic cylinder 230 is provided.
The hydraulic oil stored in 0a does not leak into the die height adjusting hydraulic cylinder 250.

Further, the upper surface 22 of the movable plate 220.
0a has hydraulic cylinders 214 for mold movement installed at four corners. Then, in the die moving hydraulic cylinder 214,
A piston 206a formed on the tie bar 206 is slidably accommodated. The lower side of the piston 206a functions as a mold clamping side oil chamber 214a, and the piston 20a
The upper side of 6a functions as the return side oil chamber 214b. The area of the upper end surface and the lower end surface of the piston 206a is set to S1. Hydraulic cylinder 2 for moving the die
The mold clamping side oil chambers 214a formed in 14 are communicated with each other by hydraulic piping Y1. The mold clamping side oil chamber 214a is connected to the hydraulic cylinder 2 for pressure transmission by the hydraulic pipe Y1, the second solenoid valve 260 and the hydraulic pipe Y10.
It is connected to the return side oil chamber 230b of 30. Here, the second solenoid valve 260 can hold the mold clamping side oil chamber 214a of the mold moving hydraulic cylinder 214 and the return side oil chamber 230b of the pressure transmitting hydraulic cylinder 230 in a communication state or a closed state, and When the second solenoid valve 260 is closed, the return-side oil chamber 230b of the pressure transmitting hydraulic cylinder 230 is connected to the oil tank 246.

Further, the respective return side oil chambers 214b formed in the die moving hydraulic cylinder 214 are communicated with each other by a hydraulic pipe Y2. And this return side oil chamber 21
4b is a hydraulic pipe Y2, a check valve 242 and a hydraulic oil pipe 23.
0c is connected to the mold clamping side oil chamber 230a of the hydraulic cylinder 230 for pressure transmission. The check valve 24
2 is the mold clamping side oil chamber 2 of the hydraulic cylinder 230 for pressure transmission.
It is attached so that the hydraulic oil can flow into 30a, and blocks the reverse flow of the hydraulic oil. Further, the hydraulic lines Y1 and Y2 can be connected to the hydraulic power source 240 side or the oil tank 246 side by the first electromagnetic valve 244. In addition, the die moving hydraulic cylinder 214
Total pressure receiving area of the four pistons 206a of 4 × S1
Is set to be larger than the area S2 of the upper end surface and the area S3 of the tip end surface of the lower piston portion 212b housed in the pressure transmitting hydraulic cylinder 230.

For example, as shown in FIG. 3, the first solenoid valve 2
When the hydraulic pipe Y1 is connected to the hydraulic source 240 and the hydraulic pipe Y2 is connected to the oil tank 246 by 44, and the second solenoid valve 260 is held in the communicating state, the maximum pressure of the hydraulic source 240 is P0, and the mold clamping operation is performed. When the hydraulic pressure inside is P1,
The hydraulic pressure P1 acts on the mold clamping side oil chamber 214a of the mold moving hydraulic cylinder 214, and at the same time, the pressure transmitting hydraulic cylinder 23.
The oil pressure P1 acts on the return side oil chamber 230b of 0. Here, as described above, the total area 4 × S1 of the piston 206a of the die moving hydraulic cylinder 214 is set to be larger than the area S2 of the lower piston portion 212b of the pressure transmitting hydraulic cylinder 230. For this reason, the force (P1 × 4 × S1) for the die moving hydraulic cylinder 214 to lower the movable plate 220 is the pressure transmitting hydraulic cylinder 230.
Force to raise the movable plate 220 (P1 ×
S2), the movable plate 220 is
1 = P1.times. (4.times.S1-S2), and moves down following the tie bar 206. As a result, the hydraulic oil flows out from the return side oil chamber 230b of the pressure transmitting hydraulic cylinder 230 regardless of the fact that the hydraulic pressure P1 is applied, and the hydraulic oil is moved to the mold clamping side oil chamber 214a of the mold moving hydraulic cylinder 214. Oil flows in. Further, the hydraulic cylinder 21 for moving the die
The hydraulic oil flows out of the return side oil chamber 214b of No. 4 and the hydraulic oil flows into the mold clamping side oil chamber 230a of the pressure transmitting hydraulic cylinder 230. Here, the hydraulic cylinder 230 for pressure transmission
The return side oil chamber 230b and the mold clamping side oil chamber 214a of the mold moving hydraulic cylinder 214 communicate with each other through hydraulic pipe Y1 and the like, and the mold clamping side oil chamber 230a of the pressure transmitting hydraulic cylinder 230 and the mold moving side The return-side oil chamber 214b of the hydraulic cylinder 214 communicates with the hydraulic pipe Y2 or the like. For this reason, hydraulic oil is supplied to both hydraulic cylinders 214 and 230.
The hydraulic power source 240 supplies the shortage of hydraulic oil. In addition, the surplus of hydraulic oil is returned to the oil tank 246. When the movable plate 220 has stopped descending (the die moving hydraulic cylinder 214 and the pressure transmitting hydraulic cylinder 230 are stopped, the hydraulic pressure of the hydraulic source 240 is P0).
The second solenoid valve 260 is shut off, and the return side oil chamber 230b of the pressure transmitting hydraulic cylinder 230 is closed by the oil tank 24.
6 is connected. Accordingly, the return-side oil chamber 230b
The hydraulic pressure P0 is no longer applied to the movable plate 22.
0 is a downward force P generated by the die moving hydraulic cylinder 214.
Receive 0x4xS1.

Further, as shown in FIG. 4, the first solenoid valve 24
4, the hydraulic pipe Y2 is connected to the hydraulic source 240, and the hydraulic pipe Y1 is connected to the oil tank 246. When the hydraulic pressure during the mold opening operation is P2, the return side oil chamber of the mold moving hydraulic cylinder 214 is connected. The hydraulic pressure P2 acts on 214b, and at the same time, the mold clamping side oil chamber 23 of the hydraulic cylinder 230 for pressure transmission.
Oil pressure P2 acts on 0a. Therefore, pressure is applied to the check valve 242 provided in the hydraulic pipe Y2 through the pilot line 242p, and the check valve 242 is held in the open state. As described above, the die moving hydraulic cylinder 214
The total area of the piston 206a of 4 × S1 is equal to the area S of the lower piston portion 212b of the pressure transmitting hydraulic cylinder 230.
Since it is greater than 3, the movable plate 220 has F2 =
The tie bar 2 under the force of P2 × (4 × S1-S3)
Ascends according to 06. As a result, the hydraulic pressure P2 is released from the clamping side oil chamber 230a of the pressure transmitting hydraulic cylinder 230.
Despite the action of, the working oil flows out, and the working oil flows into the return side oil chamber 214b of the die moving hydraulic cylinder 214. Further, the working oil flows out from the mold clamping side oil chamber 214a of the mold moving hydraulic cylinder 214, and the working oil flows into the return side oil chamber 230b of the pressure transmitting hydraulic cylinder 230. In this way, the hydraulic oil is supplied to both hydraulic cylinders 21.
When moving between 4 and 230, the hydraulic oil source 24
It is supplied from 0 and the surplus is returned to the oil tank 246.

Next, in the die casting machine 200,
A method of clamping the mold after replacing the molds 204 and 224 and further opening the mold will be described. First, as shown in FIG. 4, in the mold open state, hydraulic pressure is applied to the return side oil chamber 210b of the mold clamping hydraulic cylinder 210 to raise the mold clamping ram 212 and set the movable plate 220 to the upper limit. Hold. Further hydraulic cylinder 250 for die height adjustment
A hydraulic pressure is applied to the return side oil chamber 250b to raise the movable plate 220 to the maximum upper limit. In this state, the fixed mold 204 and the movable mold 224 are set on the fixed plate 202 by a mold changing device (not shown). When the fixed mold 204 and the movable mold 224 are completely set, the first solenoid valve 244 is actuated so that the hydraulic pipe Y1 serves as the hydraulic source 240 and the hydraulic pipe Y2 as shown in FIG.
Is connected to the oil tank 246. Further, the second solenoid valve 26
0 is maintained in the communication state. As a result, the hydraulic pressure P is applied to the mold clamping side oil chamber 214a of the mold moving hydraulic cylinder 214 and the return side oil chamber 230b of the pressure transmitting hydraulic cylinder 230.
1 acts, and the movable plate 220 moves downward F1 = P1
The tie bar 206 receives a force of × (4 × S1-S2).
Follows to descend. The lowering of the movable plate 220 is stopped when the lower piston portion 212b of the mold clamping ram 212 reaches the upper limit position of the hydraulic cylinder 230 for pressure transmission. In this state, the second solenoid valve 260 is shut off, and the return side oil chamber 230b of the pressure transmitting hydraulic cylinder 230 is connected to the oil tank 246. Thereby, the oil pressure P0 is not applied to the return side oil chamber 230b, and the movable plate 220 receives the downward force P0 × 4 × S1 by the die moving hydraulic cylinder 214.

Next, hydraulic pressure acts on the mold clamping side oil chamber 210a of the mold clamping hydraulic cylinder 210, and the mold clamping ram 212 descends, whereby the movable plate 220 descends again. Then, in a state in which the lowering of the movable plate 220 is stopped, hydraulic pressure acts on the mold clamping side oil chamber 250a of the die height adjusting hydraulic cylinder 250, the movable plate 220 is further lowered, and the lower surface 220b of the movable plate 220 is movable. Abut the mold 224. In this state, the movable mold 224
Are fixed to the movable plate 220 by a die clamper or the like (not shown). In addition, the hydraulic oil for pressure transmission is stopped from flowing out from the mold clamping side oil chamber 250a and the return side oil chamber 250b of the die height adjusting hydraulic cylinder 250, and the pressure transmitting hydraulic cylinder 230 is held (locked) at that position.
Here, the mold clamping side oil chamber 21 of the mold clamping hydraulic cylinder 210
0a to apply the hydraulic pressure P0 to the mold clamping ram 2
A downward force Fr = P0 × S0 is applied to 12. However, the check valve 242 prevents the hydraulic oil from flowing out from the mold clamping side oil chamber 230a of the pressure transmitting hydraulic cylinder 230, and the mold clamping side oil chamber 250a of the die height adjusting hydraulic cylinder 250 is also locked. The oil chamber 230 on both sides of the mold
The hydraulic pressure rises inside a and 250a. The state in which the hydraulic pressure reaches the predetermined hydraulic pressure P3 inside the mold clamping side oil chamber 230a, that is, the pressing force Fr = P0 × S0 of the mold clamping ram,
The relative movement of the hydraulic cylinder 230 for pressure transmission with respect to the mold clamping ram 212 is stopped in a state where the force supporting the mold clamping ram 212 from below is equal to P3 × S3. Then, in this state, the pressing force Fr = P0 × S0 of the mold clamping ram is transmitted to the movable plate 220 and the movable mold 224.

When the mold clamping is completed, the molds 224 and 204 are
The molten metal is pressed into the inside at high speed to perform casting. When a predetermined cooling time elapses, the solenoid valve 244 operates to connect the hydraulic pipe Y2 to the hydraulic source 240 and the hydraulic pipe Y1 to the oil tank 246, as shown in FIG.
As a result, the mold opening hydraulic pressure P2 acts on the return side oil chamber 214b of the mold moving hydraulic cylinder 214 and the mold clamping side oil chamber 230a of the pressure transmitting hydraulic cylinder 230. Further, hydraulic pressure acts on the return side oil chamber 210b of the mold clamping hydraulic cylinder 210. As a result, the movable plate 220 is
Lifting force by the hydraulic cylinder 214 for moving the mold F2 =
P2 * (4 * S1-S3) is added. If the pulling force F2 is sufficiently larger than the mold release resistance, the movable plate 220 is raised and the mold is opened. If the pulling force F2 is smaller than the mold release resistance, the lower piston portion 212b of the mold clamping ram 212 lifts the pressure transmitting hydraulic cylinder 230 upward to release the mold, and then the movable plate 214 is moved by the mold moving hydraulic cylinder 214. 220 is lifted to perform mold opening. In addition, this mold 224, 20
When casting is continued using No. 4, die clamping is performed while the die height adjusting hydraulic cylinder 250 is locked, and die opening is performed.

As described above, according to this embodiment, when the mold is clamped, the movable plate 220 is applied with the pressing force P0 × 4 × S1 from the hydraulic cylinders 214 for mold movement located at the four corners, and the mold is clamped in the central portion. A pressing force Fr = P0 × S0 is applied from the ram 212. For this reason, mold clamping is performed with good balance, and burr blow due to imbalance of mold clamping can be prevented. Further, when the mold is clamped, the second solenoid valve 260 is shut off, and the hydraulic cylinder for pressure transmission 230
Since the oil pressure is not applied to the return side oil chamber 230b of P, the reaction force P by the pressure transmitting hydraulic cylinder 230 is increased.
The clamping force is increased by 0xS2. Therefore, the mold clamping hydraulic cylinder 210 can be downsized. Further, since the pressing force Fr = P0 × S0 of the mold clamping ram 212 is equal to the force P3 × S3 that supports the mold clamping ram 212 from below, P3 is increased within an allowable range and the tip area S3 of the lower piston portion 212b is increased. The pressure transmission hydraulic cylinder 230 can be miniaturized by reducing. Further, the die height adjusting hydraulic cylinder 250 is used for the mold 204,
Since the thickness of 224 can be adjusted, the molds 204, 2
Since it is not necessary for the mold clamping hydraulic cylinder 210 to absorb the change in the thickness of 24, the working stroke length of the mold clamping hydraulic cylinder 210 can be set to the minimum value required for mold clamping. Therefore, the mold clamping hydraulic cylinder 210
The stroke length of can be shortened.

Next, a mold clamping device according to a third embodiment of the present invention will be described with reference to FIGS. The present embodiment is an application of the mold clamping device according to the present invention to a die casting machine 300. FIG. 5 is a front view of a main part of the die casting machine 300 in a mold clamped state, and FIG. 6 is a die cast in a mold opened state. 4 is a front view of the main part of the machine 300. FIG. The mold clamping device according to the present embodiment has the mold clamping ram 1 on the lower surface of the upper plate 108 of the mold clamping device according to the first embodiment.
The position detection sensor for detecting the position of 12 is installed,
Further, the hydraulic circuit connecting the pressure transmitting hydraulic cylinder 130 and the mold moving hydraulic cylinder 114 is improved, and the other structures are the same as those of the mold clamping device according to the first embodiment. At the center of the upper plate 308, a mold clamping hydraulic cylinder 310 is installed that is positioned so that its axis is parallel to the tie bar 306. The mold clamping hydraulic cylinder 310 includes a mold clamping side oil chamber 310 divided by an upper piston portion 312a of a mold clamping ram 312.
a and a return side oil chamber 310b are formed, and hydraulic pipes (not shown) are connected to the respective oil chambers 310a and 310b. In addition, the upper piston portion 312a
The area of the upper surface (on the mold clamping side oil chamber 310a side) is set to S0.

The outer peripheral surface of the mold clamping ram 312 is processed so that a plurality of magnetic pulses are generated at regular intervals in the axial direction. On the other hand, on the lower surface of the upper plate 308, a pulse sensor 370 for detecting and counting the magnetic pulse is installed near the mold clamping ram 312. The output signal of the pulse sensor 370 is input to a controller (not shown). When the mold clamping ram 312 moves, the pulse sensor 370 counts the number of magnetic pulses according to the amount of movement of the mold clamping ram 312 and transmits the magnetic pulses to the controller. The controller calculates the position of the mold clamping ram 312 based on the signal from the pulse sensor 370. Further, the controller stores the position when the mold clamping ram 312 reaches the mold clamping position. Further, when the mold is opened, a signal for stopping the operation of the mold clamping hydraulic cylinder 310 is output when the mold clamping ram 312 moves up from the mold clamping position by a predetermined dimension. That is, the pulse sensor 370 and the controller function as position detecting means, and the controller functions as position storing means and operation stopping means.

A movable plate 320 is arranged between the upper plate 308 and the fixed plate 302 so that it can be moved up and down along the tie bar 306. A pressure transmission hydraulic cylinder 330 is installed on the upper surface 320a of the movable plate 320 with its center line aligned with the die clamping hydraulic cylinder 310. The pressure transmission hydraulic cylinder 330 has the die clamping ram. A lower piston portion 312b formed at the tip of 312 is slidably accommodated. Here, the area of the front end surface (lower end surface) of the lower piston portion 312b is set to S3, and the area of the upper end surface is set to S2. In the pressure transmitting hydraulic cylinder 330, the lower piston portion 312b
The lower side functions as the mold clamping side oil chamber 330a, and the upper side of the lower piston portion 312b functions as the return side oil chamber 330b. Further, die moving hydraulic cylinders 314 are installed at four corners of the upper surface 320a of the movable plate 320. A piston 306a formed on the tie bar 306 is slidably accommodated in the die moving hydraulic cylinder 314. The lower side of the piston 306a functions as the mold clamping side oil chamber 314a, and the upper side of the piston 306a functions as the return side oil chamber 314b. The area of the upper end surface and the lower end surface of the piston 306a is set to S1.

The mold clamping side oil chambers 314a formed in the mold moving hydraulic cylinder 314 are communicated with each other by a hydraulic pipe Y1. And this mold clamping side oil chamber 314
a is connected to the return side oil chamber 330b of the pressure transmitting hydraulic cylinder 330 by the hydraulic pipe Y1, the second solenoid valve 360 and the hydraulic pipe Y10. Here, the second solenoid valve 36
0 is the mold clamping side oil chamber 31 of the mold moving hydraulic cylinder 314.
4a and the return side oil chamber 33 of the hydraulic cylinder 330 for pressure transmission
0b can be maintained in a communication state or a cutoff state, and when the second solenoid valve 360 is cut off, the return side oil chamber 330b of the pressure transmission hydraulic cylinder 330 is connected to the oil tank 346. In addition, each return side oil chamber 314b formed in the mold moving hydraulic cylinder 314 is formed.
Are connected to each other by a hydraulic pipe Y2. The return side oil chamber 314b is connected to the mold clamping side oil chamber 3 of the pressure transmitting hydraulic cylinder 330 by the hydraulic pipe Y2 and the check valve 342.
It is connected to 30a. The check valve 342 is
Clamping side oil chamber 330a of the hydraulic cylinder 330 for pressure transmission
It is mounted so that the hydraulic oil can flow in, and blocks the reverse flow of the hydraulic oil. Further, the hydraulic lines Y1 and Y2 can be connected to the hydraulic pressure source 340 side or the oil tank 346 side by the first electromagnetic valve 344. The total pressure receiving area 4 × S1 of the four pistons 306a of the die moving hydraulic cylinder 314 is equal to the lower piston portion 3 housed in the pressure transmitting hydraulic cylinder 330.
It is set larger than the area S2 of the upper end surface and the area S3 of the front end surface of 12b.

For example, as shown in FIG. 5, the first solenoid valve 3
When the hydraulic pipe Y1 is connected to the hydraulic pressure source 340 and the hydraulic pipe Y2 is connected to the oil tank 346 by 44, and the second solenoid valve 360 is held in the communicating state, the maximum pressure of the hydraulic pressure source 340 is P0, and the mold clamping operation is performed. When the hydraulic pressure inside is P1,
The hydraulic pressure P1 acts on the mold clamping side oil chamber 314a of the mold moving hydraulic cylinder 314, and at the same time, the pressure transmitting hydraulic cylinder 33.
The oil pressure P1 acts on the return side oil chamber 330b of 0. Here, as described above, the total area 4 × S1 of the piston 306a of the die moving hydraulic cylinder 314 is set larger than the area S2 of the lower piston portion 312b of the pressure transmitting hydraulic cylinder 330. Therefore, the force (P1 × 4 × S1) for the die moving hydraulic cylinder 314 to lower the movable plate 320 is the pressure transmitting hydraulic cylinder 330.
Force to raise the movable plate 320 (P1 ×
S2) is overcome and the movable plate 320 moves to F1.
= P1 × (4 × S1−S2), and moves down following the tie bar 306. As a result, the oil pressure P from the return side oil chamber 330b of the pressure transmitting hydraulic cylinder 330 is increased.
Despite the addition of 1, the hydraulic oil flows out, and the hydraulic oil flows into the mold clamping side oil chamber 314a of the mold moving hydraulic cylinder 314. Further, the hydraulic cylinder 314 for moving the die
The hydraulic oil flows out of the return side oil chamber 314b, and the hydraulic oil flows into the mold clamping side oil chamber 330a of the pressure transmitting hydraulic cylinder 330. Here, the return side oil chamber 330b of the pressure transmitting hydraulic cylinder 330 and the mold clamping side oil chamber 314a of the mold moving hydraulic cylinder 314 are the hydraulic pipe Y1 and the hydraulic pipe Y10.
Hydraulic cylinder 3 for pressure transmission
The mold clamping side oil chamber 330a of 30 and the mold moving hydraulic cylinder 3
The return side oil chamber 314b of 14 is communicated with a hydraulic pipe Y2. For this reason, the hydraulic oil is
4330, the shortage of hydraulic oil is caused by the hydraulic power source 34.
Supplied from 0. In addition, the surplus of hydraulic oil is the oil tank 34.
Returned to 6. Then, with the movable plate 320 stopped descending (the die moving hydraulic cylinder 314 and the pressure transmitting hydraulic cylinder 330 stop, the hydraulic pressure of the hydraulic source 340 becomes P0), the second solenoid valve 360 is shut off, The return-side oil chamber 330b of the pressure transmitting hydraulic cylinder 330 is connected to the oil tank 346. As a result, the oil pressure P0 is not applied to the return side oil chamber 330b, and the movable plate 320 receives the downward force P0 × 4 × S1 by the die moving hydraulic cylinder 314.

Further, as shown in FIG. 6, the first solenoid valve 34
4, the hydraulic pipe Y2 is connected to the hydraulic source 340, and the hydraulic pipe Y1 is connected to the oil tank 346. When the hydraulic pressure during the mold opening operation is P2, the return side oil chamber of the mold moving hydraulic cylinder 314 is The hydraulic pressure P2 acts on 314b, and at the same time, the mold clamping side oil chamber 33 of the hydraulic cylinder 330 for pressure transmission.
Oil pressure P2 acts on 0a. Therefore, pressure is applied to the check valve 342 provided in the hydraulic pipe Y2 through the pilot line 342p, and the check valve 342 is held in the open state. As described above, the die moving hydraulic cylinder 314
The total area of the piston 306a of 4 × S1 is equal to the area S of the lower piston portion 312b of the hydraulic cylinder 330 for pressure transmission.
Since it is larger than 3, the movable plate 320 has F2 =
The tie bar 3 under the force of P2 × (4 × S1-S3)
Ascends according to 06. As a result, the hydraulic pressure P2 is released from the form-clamping side oil chamber 330a of the pressure transmitting hydraulic cylinder 330.
The working oil flows out despite the fact that the action is performed, and the working oil flows into the return side oil chamber 314b of the die moving hydraulic cylinder 314. Further, the working oil flows out from the mold clamping side oil chamber 314a of the mold moving hydraulic cylinder 314, and the working oil flows into the return side oil chamber 330b of the pressure transmitting hydraulic cylinder 330. In this way, the hydraulic oil is transferred to both hydraulic cylinders 31.
4330, the shortage of hydraulic oil is caused by the hydraulic power source 34.
It is supplied from 0 and the surplus is returned to the oil tank 346.

Next, in the die casting machine 300,
A method of performing mold clamping after exchanging the molds 304 and 324 and further opening the mold will be described. First, as shown in FIG. 6, while the mold is opened, hydraulic pressure is applied to the return side oil chamber 310b of the mold clamping hydraulic cylinder 310 to raise the mold clamping ram 312 and move the movable plate 320 to the uppermost limit. Hold on. In this state, the fixed mold 304 and the movable mold 324 are set on the fixed plate 302 by a mold exchanging device (not shown). When the fixed mold 304 and the movable mold 324 are completely set, the first electromagnetic valve 344
The hydraulic pipe Y1 is connected to the hydraulic pressure source 340, and the hydraulic pipe Y2 is connected to the oil tank 346, as shown in FIG. Further, the second solenoid valve 360 is held in the communicating state. As a result, the hydraulic pressure P1 acts on the mold clamping side oil chamber 314a of the mold moving hydraulic cylinder 314 and the return side oil chamber 330b of the pressure transmitting hydraulic cylinder 330, and the movable plate 320 moves downward F1 = P1 × (4 × S1 Under the force of -S2), the tie bar 306 is followed to descend. Then, with the lower piston portion 312b of the mold clamping ram 312 reaching the upper limit position of the hydraulic cylinder 330 for pressure transmission,
When the movable plate 320 stops descending, the movable plate 3
20 is held in that position. In this state, the hydraulic pressure P0 acts on the mold clamping side oil chamber 310a of the mold clamping hydraulic cylinder 310 to lower the mold clamping ram 312. As a result, the movable plate 320 descends again, and the lower surface 320b of the movable plate 320 contacts the movable mold 324.

Next, the second solenoid valve 360 is shut off, and the return side oil chamber 330b of the pressure transmitting hydraulic cylinder 330 is connected to the oil tank 346. Thereby, the oil pressure P0 is not applied to the return side oil chamber 230b, and the movable plate 220 receives the downward force P0 × 4 × S1 by the die moving hydraulic cylinder 214. In this state, the movable die 324 is fixed to the movable plate 320 by a die clamper or the like (not shown). Here, since the hydraulic pressure P0 continues to act on the mold clamping side oil chamber 310a of the mold clamping hydraulic cylinder 310, the downward force Fr = P0 × S0 is applied to the mold clamping ram 312. However, since the check valve 342 prevents the hydraulic oil from flowing out of the mold clamping side oil chamber 330a of the pressure transmitting hydraulic cylinder 330, the hydraulic pressure rises inside the mold clamping side oil chamber 330a. The state in which the hydraulic pressure reaches the predetermined hydraulic pressure P3 inside the mold clamping side oil chamber 330a, that is, the pressing force Fr = P0 × S0 of the mold clamping ram is equal to the force P3 × S3 that supports the mold clamping ram 312 from below. Clamping ram 31
The descent of 2 stops. And in this state the movable plate 3
20 and the movable mold 324 are pressed by the mold clamping ram Fr =
P0 × S0 is transmitted. Further, the position of the mold clamping ram 312 in this state is calculated and stored in the controller based on the pulse count value from the pulse sensor 370.

In this way, the movable plate 320 has
A pressing force P0 × 4 × S1 is applied from the die moving hydraulic cylinders 314 located at the four corners, and a pressing force Fr = P0 × S0 is applied to the central portion from the die clamping ram 312, so that the die clamping is performed with good balance. . When the mold clamping is completed, the molten metal is pressed into the molds 324 and 304 at a high speed and casting is performed. When a predetermined cooling time elapses, the return side oil chamber 3 of the mold clamping hydraulic cylinder 310 is closed.
The hydraulic pressure acts on 10b to raise the mold clamping ram 312 from the mold clamping position by a predetermined dimension. Then, in this state, the operation of the mold clamping hydraulic cylinder 310 is stopped and the mold clamping ram 312 is held at this position. Next, as shown in FIG. 6, the first solenoid valve 344 is activated to connect the hydraulic pipe Y2 to the hydraulic source 340, and the hydraulic pipe Y1 is connected to the oil tank 34.
6 is connected. As a result, the hydraulic cylinder 3 for moving the mold
Return side oil chamber 314b and pressure transmitting hydraulic cylinder 3
The mold opening hydraulic pressure P2 acts on the mold clamping side oil chamber 330a of 30. This causes the movable plate 320 to have a pulling force F2 = P2 × by the hydraulic cylinder 314 for mold movement.
(4 * S1-S3) is added. If the pulling force F2 is sufficiently larger than the mold release resistance, the movable plate 320 rises and the mold opening is performed. If the pulling force F2 is smaller than the mold release resistance, the mold clamping ram 312
Lower piston part 312b of the hydraulic cylinder 3 for pressure transmission
The mold 30 is lifted up and released from the mold, and then the movable plate 320 is lifted by the mold moving hydraulic cylinder 314 to open the mold.

As described above, according to this embodiment, the position of the mold clamping ram 312 (mold clamping position) at the time of mold clamping can be stored by the pulse sensor 370 and the controller.
Further, when the mold clamping ram 312 rises from the mold clamping position by a predetermined dimension when the mold is opened, the mold clamping hydraulic cylinder 310 is stopped by a signal from the controller. Therefore, the mold clamping hydraulic cylinder 310 can be operated within the minimum necessary range.
The amount of hydraulic oil used at 10 is reduced. Also, the time required for mold opening is shortened. Further, during mold clamping, a pressing force P0 × 4 × S1 is applied to the movable plate 320 from the mold moving hydraulic cylinders 114 located at the four corners, and a pressing force Fr = P0 from the mold clamping ram 112 is further applied to the central portion.
× S0 is added. For this reason, mold clamping is performed with good balance, and burr blow due to imbalance of mold clamping can be prevented. Further, since the second solenoid valve 360 is shut off before the mold is clamped and no oil pressure is applied to the return side oil chamber 330b of the pressure transmitting hydraulic cylinder 330, the reaction force P0 × S2 due to this pressure transmitting hydraulic cylinder 330. Only the mold clamping force is improved. Therefore, the mold clamping hydraulic cylinder 310 can be downsized. In the above embodiment, the mold clamping device according to the present invention is used in the vertical die casting machine, but it goes without saying that it can also be used in the horizontal die casting machine and the injection molding machine.

[0039]

According to the present invention, when a mold is clamped, a pressing force from a mold moving hydraulic cylinder provided on each tie bar is evenly applied to the edge of the movable mold, and the mold clamping ram is pressed. Since the pressure is applied to the center, the mold clamping balance is good. This reduces troubles such as burr blowing.
Furthermore, since hydraulic oil is exchanged between the die moving hydraulic cylinder and the pressure transmitting hydraulic cylinder, the amount of hydraulic oil newly supplied from the outside is reduced. Therefore, hydraulic equipment such as a hydraulic pump, an oil tank, and hydraulic piping can be downsized, and the equipment cost can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of a die casting machine equipped with a die clamping device according to a first embodiment in a die clamping state.

FIG. 2 is a front view of the die casting machine equipped with the die clamping device according to the first embodiment in a die open state.

FIG. 3 is a front view of a die casting machine equipped with a die clamping device according to a second embodiment in a die clamping state.

FIG. 4 is a front view of a die casting machine equipped with a mold clamping device according to a second embodiment in a mold open state.

FIG. 5 is a front view of a die casting machine equipped with a die clamping device according to a third embodiment in a die clamping state.

FIG. 6 is a front view of a die casting machine equipped with a die clamping device according to a third embodiment in a die open state.

FIG. 7 is a front view of a die casting machine equipped with a conventional die clamping device in a die clamping state.

[Explanation of symbols]

104 Fixed Mold 106 Tie Bar 124 Movable Mold 110 Hydraulic Cylinder for Clamping 112 Mold Clamping Ram 114 Cylinder for Clamping 130 Cylinder for Pressure Transfer 130 Hydraulic Cylinder for Pressure Transmission 142 Check Valve (Lock Mechanism) 250 Hydraulic Cylinder for Die Height Adjustment (hydraulic for position adjustment) Cylinder) 370 Pulse sensor (position detection means) Y1, Y2 Hydraulic circuit

Claims (3)

[Claims] 1. A mold is clamped by moving a movable mold along a plurality of tie bars and applying a pressing force of a mold clamping ram to the movable mold while the movable mold is engaged with a fixed mold. In the mold clamping device for performing, a mold moving hydraulic cylinder, which is installed in each of the tie bars and moves the movable mold to a position where the movable mold is engaged with the fixed mold while pressing the movable mold, and the mold clamping ram. A mold clamping hydraulic cylinder to be operated, and the coaxially arranged between the mold clamping ram and the movable mold, and extending the piston rod according to an increase in the distance between the mold clamping ram and the movable mold. The hydraulic oil for pressure transmission and the hydraulic oil flowing out from the hydraulic cylinder for mold movement are guided to the inlet of the hydraulic cylinder for pressure transmission, and the hydraulic oil flowing out of the hydraulic cylinder for pressure transmission is transferred to the hydraulic cylinder for mold movement. A hydraulic circuit configured to be guided to the inlet of the cylinder, and a lock mechanism that is installed in the hydraulic circuit and that prohibits the hydraulic fluid from flowing out from the hydraulic cylinder for pressure transmission during mold clamping. A characteristic mold clamping device. 2. The mold clamping device according to claim 1, wherein between the pressure transmitting hydraulic cylinder and the movable mold,
A mold clamping device, wherein a position adjusting hydraulic cylinder for adjusting the position of the pressure transmitting hydraulic cylinder with respect to the movable mold is provided. 3. The mold clamping device according to claim 1, wherein position detecting means for detecting a position of the mold clamping ram, position storage means for storing a position of the mold clamping ram at the time of mold clamping, A mold clamping device comprising: an operation stopping means for stopping the operation of the mold clamping hydraulic cylinder when the mold clamping ram moves from the mold clamping position by a predetermined distance.