JPH05237625A - Die clamping device - Google Patents

Abstract

PURPOSE:To reduce working cost and floor area for setting an apparatus, to use together with a boost cylinder, to make opening/closing speed of a die the same and also to increase opening force of the die by omitting the inner diameter work and also arranging a prefill valve to rear lower part of a die clamping cylinder. CONSTITUTION:One end of a die clamping ram loosely inserted in the die clamping cylinder is fixed to a shifting die plate 26 and also, a hollow part 30 is formed between the other end part and the bottom part of the clamping cylinder. The prefill valve 48 is arranged between this hollow part 30 and an oil tank 46, and the boost cylinder 40 is fixed to a flange part in the die clamping cylinder, and the shifting die plate 26 is restrained to the end part of a rod 42 of a piston 41 inserted so as to be possible to shift in advancing/ retreating direction in the inner part of the boost cylinder. A ram 44 fixing the one end to the boost cylinder 40 and forming opening hole passage 45 in the inner part, is inserted in a cylindrical part 43 formed at the end part of the rod 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device for an injection molding machine, and more particularly to simplification of a mold clamping cylinder structure.

[0002]

2. Description of the Related Art In a direct pressure type mold clamping device used in an injection molding machine, a die casting machine, etc., it is necessary to open and close the mold at a high speed in order to shorten the molding cycle. On the other hand, in order to resist the molding pressure. It requires a strong mold clamping force. In order to satisfy such a condition, the mechanism of this type of direct pressure type mold clamping device is generally complicated, and there are various types as shown in FIG. That is, (a) shown in FIG. 5 shows a booster ram type mold opening / closing device. This mold opening / closing device slides a mold clamping ram 12 in a mold clamping cylinder 10 and fast-forwards rams into the cylinder of the mold clamping ram 12. Pressure oil for mold closing is supplied from an oil passage provided in 14, and high-speed mold closing is performed by supplying pressure oil from the rapid feed ram 14 into the cylinder of the mold clamping ram 12 to perform strong mold clamping. The mold clamping cylinder 10 is configured so that pressure oil is supplied to the rear oil chamber, and the mold opening is performed by supplying pressure oil to the front oil chamber of the mold clamping cylinder 10.
A prefill valve 16 is provided behind the central axis of 0.

On the other hand, the conventional apparatus shown in FIG. 5B is constructed such that an auxiliary cylinder 18 for high-speed mold opening / closing is provided separately from the mold clamping cylinder. However, such a conventional device has the following problems. That is,
In the booster ram type shown in FIG. 5 (a), since the mold opening is performed in the front oil chamber of the mold clamping cylinder 10, it is required that the entire surface of the inner surface of the mold clamping cylinder 10 be machined with high accuracy. Due to the large diameter, precision processing is difficult and processing costs are high. Also,
In the case where the front oil chamber of the large-diameter mold clamping cylinder 10 is used for such mold opening, the effective pressure receiving area of the front oil chamber is the cylinder in the mold clamping ram 12 when the mold is closed. However, the mold opening force becomes large, but the mold opening speed becomes slower than the mold closing speed, and the prefill valve 16 is located rearward on the central axis of the mold clamping cylinder 10.
Since the mold clamping device is provided, the whole mold clamping device becomes long and there is a problem that the installation floor area increases.

Further, the auxiliary cylinder 1 shown in FIG.
In the mold opening / closing device having 8, since the high speed mold opening / closing is performed by the auxiliary cylinder 18 having a small diameter, there are few problems in the cylinder machining as described above, but the front and rear oil chambers of the auxiliary cylinder defined by the piston are Since the areas differ only by the cross-section integral of the piston rod, even if a constant flow rate of pressure oil is supplied from the hydraulic source, the mold closing speed and the mold opening speed are different and the mold closing speed becomes slower if the mold opening force is increased. In addition, when using such an auxiliary cylinder as a drive cylinder for opening and closing the mold, in terms of the balance of the mold opening and closing operation,
Since a plurality of auxiliary cylinders are required around the mold clamping cylinder, there is a problem that the entire apparatus becomes large, and each of the conventional apparatuses has a problem.

As a mold clamping device proposed to solve the above-mentioned problems, Japanese Patent Laid-Open No. 63-278815.
In this mold clamping device, a mold clamping ram, the tip of which is connected to the back surface of a movable plate, is inserted in a cylinder chamber formed in the mold clamping cylinder so that the mold clamping ram can advance and retreat. Pressure oil is supplied from the oil passage. Then, a rapid feed cylinder that opens to the rear surface of the ram is formed in the mold clamping ram, and a rapid feed piston whose base is fixed to the rear end of the mold clamping cylinder is slid into this rapid feed cylinder. Is divided into a front oil chamber and a rear oil chamber. The effective pressure receiving area between the front oil chamber and the rear oil chamber is set to be 2: 1 and the front oil chamber and the rear oil chamber are clamped via two oil passages formed in the rapid feed piston. It is connected to a hydraulic system outside the cylinder.

Further, the oil passage leading to the rear oil chamber is also opened to the front oil chamber by the connecting oil passage, and this connecting oil passage is located in the portion of the oil passage that extends back and forth through the opening to the rear oil chamber. The valve body is slidably formed in the inside thereof. When the valve body is located at the left end of the communication oil passage, the rear oil chamber and the front oil chamber communicate with each other through the opening and the communication oil passage, and when the valve body is located at the right end of the communication oil passage. The oil passage communicates with the rear oil chamber through the opening, and the rear oil chamber and the front oil chamber are shut off from each other.

The cylinder chamber of the mold clamping cylinder is connected to the charge tank through an oil passage provided in a partition wall on the rear end side of the mold clamping cylinder, a through hole, and a suction pipe connected to the oil passage.
A prefill valve operated by hydraulic pressure is provided at the rear end on the central axis of the mold clamping cylinder, and this prefill valve slidably slides on the fast-forward piston and is fitted into the through hole provided in the partition wall at the moving position. It is configured so that the connection between the cylinder chamber and the external charge tank can be cut off.

Furthermore, in the mold opening / closing rapid feeding device shown in another embodiment, the mold clamping cylinder is divided into a front oil chamber and a rear oil chamber by the piston portion of the mold clamping ram, and these chambers are provided in the piston portion. It is connected by a communication passage. Further, a charge cylinder is provided in parallel with the mold clamping cylinder, a tip is connected to the movable plate, and is equipped with a piston rod that moves forward and backward together with the movable plate, and is partitioned into a front oil chamber and an air chamber by a piston fixed to the piston rod. The front oil chamber communicates with the front oil chamber of the mold clamping cylinder by an oil passage.

Further, a cap-shaped on-off valve is fitted in a small diameter portion of the mold clamping ram extending into the rear oil chamber of the mold clamping cylinder so as to be movable in the axial direction of the mold clamping ram, and its sleeve-shaped part is clamped. Guided on the peripheral surface of the small-diameter portion of the ram, the communication path can be closed by the end surface of the sleeve-shaped portion. A cylinder space is defined between the inner surface of the on-off valve and the outer peripheral surface of the small diameter portion, and this cylinder space is configured to communicate with the rear oil chamber by a through hole provided in the mold clamping ram. The effective pressure receiving area of the rear oil chamber of the mold clamping cylinder is set to be equal to the sum of the front oil chamber of the mold clamping cylinder and the front oil chamber of the charge cylinder.

[0010]

However, the mold clamping device of this type has a complicated structure in the former case, and the mold opening force becomes small when the mold opening / closing speed is made high, and the mold clamping force is further reduced. Since the prefill valve is provided at the rear of the cylinder, there is a problem that the total length of the mold clamping device becomes long and the installation floor area occupied by the device increases more than necessary. Further, in the latter case, in addition to the same problems as in the former case, there are many unsolved problems such as precision machining of the inner surface of the mold clamping cylinder is difficult and the machining cost is high. ..

The object of the present invention is to significantly reduce the machining cost by eliminating the need for machining the inner diameter of the mold clamping cylinder, and to provide the prefill valve on the rear side surface of the mold clamping cylinder so that the entire length of the apparatus can be improved. It is an object of the present invention to provide a mold clamping device capable of reducing the installation floor area by shortening the mold, and at the same time increasing the mold opening / closing speed to increase the mold opening force.

[0012]

To achieve the above object, a movable die plate is fixed to one end of a mold clamping ram inserted in a mold clamping cylinder, and this movable die plate is fixed to the mold clamping cylinder and a fixed die plate. In a mold clamping device configured to be guided and supported by a plurality of tie bars that communicate with and to move back and forth with respect to a fixed die plate, the mold clamping device inserts a mold clamping ram loosely and at the same time, the outer periphery of the ram on the opening side. It is sealed and slidably inserted, and a mold clamping cylinder with a cavity formed between the mold clamping ram end and bottom and a boost cylinder fixed to this mold clamping cylinder are provided so that they can move forward and backward. A rod for locking the movable die plate and moving the movable die plate forward and backward with respect to the fixed die plate, and a rod at the other end of the rod that can slide in the boost cylinder. A piston part defining a bottom chamber and a cylinder chamber inside and a cylinder part opening in the axial direction at the rear end of the rod. A ram mounted on the bottom of the boost cylinder, an open passage formed through the ram in the direction of the central axis of the ram, and a prefill valve for blocking communication between the cavity of the mold clamping cylinder and the oil tank. It is characterized in that it is configured.

Further, in the mold clamping device of the present invention, the movable die plate is fixed to one end of the mold clamping ram inserted in the mold clamping cylinder, and this movable die plate connects the mold clamping cylinder and the fixed die plate. In a mold clamping device configured to be guided and supported by a plurality of tie bars to move back and forth with respect to a fixed die plate, the mold clamping device loosely fits and inserts a mold clamping ram and hermetically seals the outer periphery of the ram on the opening side. A mold clamping cylinder with a cavity formed between the end and bottom of this mold clamping ram, and a boost cylinder fixed to this mold clamping cylinder so that it can move forward and backward and one end moves. And a first rod that moves the movable die plate forward and backward with respect to the fixed die plate and is slidable in the boost cylinder at the other end of the first rod. A piston part which is inserted and defines the interior thereof into a bottom chamber and a cylinder chamber, and the other end of the piston part opposite to the first rod so that the other end projects to the outside of the boost cylinder. It is characterized by comprising a second rod connected on the same axis as the rod and a prefill valve for blocking communication between the cavity of the mold clamping cylinder and the oil tank.

Further, in the mold clamping apparatus of the present invention, the movable die plate is fixed to one end of the mold clamping ram inserted in the mold clamping cylinder, and this movable die plate connects the mold clamping cylinder and the fixed die plate. In a mold clamping device configured to be guided and supported by a plurality of tie bars to move back and forth with respect to a fixed die plate, the mold clamping device loosely fits and inserts a mold clamping ram and hermetically seals the outer periphery of the ram on the opening side. A mold clamping cylinder having a cavity formed between the end and the bottom of the mold clamping ram is slidably inserted, and a boost cylinder that opens in the axial direction is formed at the rear end of the mold clamping ram. The boost ram is attached to the bottom of the cavity of the mold clamping cylinder and the other end of the boost ram is inserted into the boost cylinder, and an auxiliary cylinder fixed to the mold clamping cylinder is provided to move forward and backward. A rod that is locked to the die plate and moves the movable die plate forward and backward with respect to the fixed die plate, and a rod at the other end of the rod that is slidably inserted into the auxiliary cylinder and It is characterized in that it is constituted by a piston portion which defines a bottom chamber and a cylinder chamber, and a prefill valve which shuts off communication between the cavity of the mold clamping cylinder and the oil tank.

Further, in the mold clamping apparatus of the present invention, the movable die plate is fixed to one end of the mold clamping ram inserted in the mold clamping cylinder, and this movable die plate connects the mold clamping cylinder and the fixed die plate. In a mold clamping device configured to be guided and supported by a plurality of tie bars to move back and forth with respect to a fixed die plate, the mold clamping device loosely fits and inserts a mold clamping ram and hermetically seals the outer periphery of the ram on the opening side. A mold clamping cylinder having a cavity formed between the mold clamping ram end and the bottom and a boost cylinder fixed to the fixed die plate are provided so as to be able to move forward and backward, and one end of the mold plate is movable. And a rod for moving the movable die plate forward and backward with respect to the fixed die plate,
A piston portion at the other end of the rod, which is slidably inserted into the boost cylinder to define the inside into a bottom chamber and a cylinder chamber, a cavity portion of the mold clamping cylinder, and an oil tank. It is characterized in that it is configured with a prefill valve that cuts off communication between the two.

[0016]

According to the mold clamping apparatus of the present invention, the machining cost is greatly reduced by eliminating the inner diameter machining of the mold clamping cylinder, and the prefill valve is provided on the rear side surface of the mold clamping cylinder so as to face downward. As a result, the total length of the apparatus can be shortened and the installation floor area can be reduced, and at the same time, the mold opening / closing speed can be made uniform and the mold opening force can be increased.

[0017]

EXAMPLE Next, an example of the mold clamping device according to the present invention will be described.
The following is a detailed description with reference to the accompanying drawings. FIG. 1A is a sectional view of an essential part showing an embodiment of the mold clamping device of the present invention, and FIG. 1B is an overall side view of the mold clamping device.

In the drawings, reference numeral 20 is a fixed die plate for mounting a fixed die, and a mold clamping cylinder 22 is arranged in contact with the fixed die plate 20. The mold clamping cylinder 22 and the fixed die plate are connected by a plurality of tie bars 24. A movable die plate 26 is guided and supported by the tie bars 24 with respect to the fixed die plate 20 by the action of a boost cylinder 40, which will be described later, and at the same time, a bottom portion of the movable die plate 26 is also slidably supported by a slide plate 25. Has been done.

A mold clamping ram 28 is provided inside the mold clamping cylinder 22.
Is loosely inserted so that it can move back and forth, the outer periphery of the mold clamping ram 28 is sealed by a seal at the opening of the mold clamping cylinder 22, and the back surface of the movable die plate 26 is fixed to one end of the mold clamping ram 28. A cavity (A chamber) 30 is formed between the other end and the bottom of the mold clamping cylinder 22.

Flange portion 22A of the mold clamping cylinder 22
The main body of the boost cylinder 40 for advancing and retracting the moving die plate 26 is fixed to the side wall of the. A piston portion 41 formed at one end of a rod 42 is slidably fitted in the boost cylinder 40, and the inside of the cylinder is covered by the piston portion 41 in a bottom chamber 36 and a cylinder chamber (C chamber) 38.
And the other end of the rod 42 is locked to the moving die plate 26.

Further, the inside of the rear end of the rod 42 is axially opened to form a cylinder portion 43 therein, and one end of the cylinder portion (D chamber) 43 is attached to the bottom portion of the boost cylinder 40. The ram 44 is slidably fitted.
An opening passage 45 is formed in the ram 44 in the axial direction so that pressure oil can be introduced into the cylinder portion (D chamber) 43 from the outside. A pre-fill valve 48 is provided to cut off the communication between the hollow portion (A chamber) 30 of the cylinder and the hydraulic tank 46.

The operation of the mold clamping cylinder thus constructed will be described in detail below. About mold clamping forward movement. When the prefill valve 48 is opened by the mold clamping start command, pressure oil is introduced from the A port 50 into the cylinder portion (D chamber) 43, and as a result, the piston portion 41 slidably fitted in the boost cylinder 40. A rod 42 whose one end is locked to the die plate 26 by
Moves forward, and the moving operation of the rod 42 moves the movable die plate 26 forward in the mold clamping.

Subsequently, the oil in the hydraulic tank 46 is introduced into the cavity 30 of the mold clamping cylinder 22, and the tank 46 is further filled.
Oil is introduced into the bottom chamber 36 of the boost cylinder 40. At the same time, the forward movement of the rod 42 causes the oil in the cylinder chamber 38 (C chamber) to be discharged to the outside. It is needless to say that the working medium introduced into the bottom chamber 36 of the boost cylinder 40 may be air instead of oil.

Regarding the operation of generating the mold clamping force. The prefill valve 48 is closed at the forward limit position of the moving die plate 26, and C is placed in the cavity (A chamber) 30 of the mold clamping cylinder 22.
When pressure oil is introduced from the port 54, the pressure oil acts on the cavity 30 and a mold clamping force is generated.

Regarding the generation of mold opening force. In response to a mold opening command, the pressure oil in the cavity chamber (A chamber) 30 is drained from the C port 54, the prefill valve 48 is subsequently opened, and the pressure oil is introduced into the cylinder chamber (C chamber) 38 of the boost cylinder 40. Then, a mold opening force corresponding to the pressure oil that acts on the pressure receiving area of the piston portion 41 of the cylinder chamber 38 is generated.

About high-speed mold opening operation. By introducing pressure oil to the cylinder chamber 38 and retracting the rod 42 of the boost cylinder 40, the cylinder portion (D
Pressure oil flowing out of the chamber 43) into the cylinder portion (D chamber) 4
By introducing into the cylinder chamber (C chamber) 38 formed so that the ratio of the pressure receiving area with respect to 3 is 1: 2, a differential circuit is formed and high-speed mold opening operation can be performed, and the mold opening / closing speed is also increased. Can be equal.

Then, as the rod 42 retracts, the pressure oil in the bottom chamber 36 of the boost cylinder 40 is returned to the hydraulic tank 46.

Next, another embodiment will be described in detail with reference to FIG. The same components as those of the structure shown in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Flange portion 22A of mold clamping cylinder 22
A boost cylinder 40 for advancing and retreating the moving die plate 26 is fixed to the cylinder, and a piston portion 41 provided at the center of the rod is slidably fitted in the boost cylinder 40 and is mounted in the cylinder. The interior of 40 is divided into a bottom chamber 36 and a cylinder chamber (C chamber) 38.

At both ends of the piston portion 41, first and second rods 47a, 4 having different diameters on the same axis are provided.
7b is connected, the end of the first rod 47a is locked to the moving die plate 26, and the second rod 47b is connected.
The free end of the is extended in the axial direction so as to project to the outside of the boost cylinder 40.

The operation of the mold clamping cylinder thus constructed will be described in detail below. About mold clamping forward movement. When the pre-fill valve 48 is opened by the mold clamping start command, pressure oil is introduced into the bottom chamber 36 of the boost cylinder 40, and as a result, the piston 41 slidably inserted into the boost cylinder 40 causes the piston 41 to move. The first rod 47a having one end connected to and the other end locked to the moving die plate 26 advances the mold.
Subsequently, the oil in the hydraulic tank 46 is introduced into the cavity chamber (A chamber) 30 of the mold clamping cylinder 22. Further, the oil in the cylinder chamber (C chamber) 38 is discharged to the outside by the forward movement of the first rod 47a.

Regarding the generation of mold clamping force. The prefill valve 48 is closed at the forward limit position of the moving die plate 26, and the C port 5 is placed in the cavity chamber (A chamber) 30 of the mold clamping cylinder 22.
When the pressure oil is introduced from 4, the pressure oil acts on the cavity chamber (A chamber) 30 and a mold clamping force is generated.

Generation of mold opening force. In response to a mold opening command, the pressure oil in the cavity chamber (A chamber) 30 is drained from the C port 54, the prefill valve 48 is subsequently opened, and the pressure oil is introduced into the cylinder chamber (C chamber) 38 of the boost cylinder 40. Then, a large mold opening force equivalent to the pressure oil that acts on the pressure receiving area of the piston 41 on the cylinder chamber side is generated.

About high speed mold opening operation. The oil in the bottom chamber 36 of the boost cylinder 40 is discharged by retreating the rod 47b of the boost cylinder 40.
7b is formed to have a diameter difference so that the pressure receiving area ratio of the left and right chambers of the piston 41 is 1: 2, and the pressure oil discharged from the bottom chamber 36 is introduced into the cylinder chamber 38 (C chamber) to make a differential. By forming a circuit, a high-speed mold opening operation can be obtained and the mold opening / closing speeds can be equalized.

Next, another embodiment will be described in detail with reference to FIG. The same components as those of the structure shown in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Inside the mold clamping cylinder 22, a boost cylinder 57 is formed in the axial direction in a mold clamping ram 28 which is loosely inserted into the mold clamping cylinder 22, and one end of the boost ram 60 is attached to the bottom of the mold clamping cylinder 22. The end is fitted into the boost cylinder 57. A cylinder 47 main body for backward movement of the moving die plate 26 is fixed to the flange portion 22A of the mold clamping cylinder 22, and a piston portion 41 formed at one end of a rod 49 is slidable in the cylinder 47. The piston 4 is inserted and fitted into the cylinder 4
The interior of 7 is divided into a bottom chamber 36 and a cylinder chamber 38. A pre-fill valve 48 is provided in the lower rear portion of the mold clamping cylinder 22 to disconnect the cavity chamber (A chamber) 30 of the mold clamping cylinder 22 from the hydraulic tank 46.

The operation of the mold clamping cylinder thus configured will be described below. About mold clamping forward movement. When the prefill valve 48 is opened by the mold clamping start command, the B port 5 is added to the bottom chamber (B chamber) 56 of the boost cylinder 57 formed in the mold clamping ram 28.
The pressure oil is introduced via 8 and as a result, the mold clamping ram 28
Is fixed to the moving die plate 26, the mold clamping operation is performed by moving the moving die plate 26 forward.

Then, the oil in the hydraulic tank 46 is introduced into the cavity chamber (A chamber) 30 of the mold clamping cylinder 22. Also,
The oil in the cylinder chamber 38 is discharged to the hydraulic tank 46 by the forward movement of the moving die plate 26, and at the same time, the cylinder bottom chamber 36 is filled with air or the oil in the hydraulic tank 46 is sucked.

Regarding the generation of mold clamping force. The prefill valve 48 is closed at the forward limit position of the moving die plate,
When oil is introduced from the C port 54 into the cavity chamber (A chamber) 30 of the mold clamping cylinder 22, pressure oil acts on the cavity chamber (A chamber) 30 to generate a mold clamping force.

Generation of mold opening force. In response to the mold opening command, the pressure oil in the cavity chamber (A chamber) 30 is drained from the C port 54, the prefill valve 48 is subsequently opened, and the pressure oil is applied to the pressure receiving area of the piston portion 41 of the cylinder chamber 38 of the cylinder 47. A mold opening force corresponding to the acting pressure oil is generated.

About high speed mold opening operation. Due to the backward movement of the mold clamping ram 28, the pressure oil in the boost cylinder 57 is discharged from the B port 58 to the hydraulic tank 46. This pressure oil is transferred between the bottom chamber (B chamber) 56 of the boost cylinder 57 and the cylinder chamber 38. By introducing into the cylinder chamber 38 formed to have a pressure receiving area ratio of 1: 2 to form a differential circuit, high-speed mold opening operation can be performed and mold opening / closing speeds can be equalized. In this case, the oil or air in the bottom chamber 36 is discharged to the tank 46.

Next, another embodiment will be described in detail with reference to FIG. The same components as those of the structure shown in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The mold clamping cylinder 22 has the same configuration as that of FIG. 2 described above, and the main body of the boost cylinder 47 for advancing and retracting the moving die plate 26 is fixed to the side wall of the fixed die plate 20. A piston portion 41 formed at one end of a rod 49 is slidably fitted in the boost cylinder 47, and the inside of the cylinder is defined by the piston portion 41 into a bottom chamber 36 and a cylinder chamber (C chamber) 38. The other end of the rod 49 is locked to the moving die plate 26. The pressure receiving area ratio of the piston portion 41 between the cylinder chamber (C chamber) 38 and the bottom chamber 36 is 2: 1.

The mold clamping cylinder thus configured operates as follows. That is, when the pre-fill valve 48 is opened by the mold clamping start command, pressure oil is introduced into the bottom chamber 36 of the boost cylinder 47, and as a result, the piston portion 41 slidably inserted into the boost cylinder 47 causes Rod 4 whose one end is locked to the moving die plate 26
9 moves backward, and the moving die plate 26 moves forward in the mold clamping. Then, the oil in the hydraulic tank 46 is introduced into the cavity chamber (A chamber) 30 of the mold clamping cylinder 22, and the oil in the cylinder chamber (C chamber) 38 is discharged to the outside by the backward movement of the rod 49.

Regarding the generation of mold clamping force. The prefill valve 48 is closed at the forward limit position of the moving die plate 26, and the C port 5 is placed in the cavity chamber (A chamber) 30 of the mold clamping cylinder 22.
When the pressure oil is introduced from 4, the pressure oil acts on the cavity chamber (A chamber) 30 and a mold clamping force is generated.

Generation of mold opening force. In response to a mold opening command, the pressure oil in the cavity chamber (A chamber) 30 is drained from the C port 54, the prefill valve 48 is subsequently opened, and the pressure oil is introduced into the cylinder chamber (C chamber) 38 of the boost cylinder 47. Then, a large mold opening force equivalent to the pressure oil that acts on the pressure receiving area of the piston portion 41 on the cylinder chamber side is generated.

About high-speed mold opening operation. The oil in the bottom chamber 36 of the boost cylinder 47 is discharged by the forward movement of the rod 49 of the boost cylinder 47, but the cylinder chamber (C chamber)
38 and the pressure receiving area ratio of the piston portion 41 of the bottom chamber 36 is 2:
1 to form a differential circuit by introducing pressure oil discharged from the bottom chamber 36 into the cylinder chamber 38 (C chamber) to obtain a high-speed mold opening operation and equalize mold opening / closing speeds. You can

[0045]

As is apparent from the above-described embodiments, according to the mold clamping apparatus of the present invention, the mold clamping ram is loosely fitted and the outer periphery of the ram is hermetically closed on the opening side and slidably inserted. A mold clamping cylinder having a cavity formed between the end and the bottom of the mold clamping ram and a boost cylinder fixed to the mold clamping cylinder are provided so as to be able to move forward and backward, and one end of the cylinder is locked to a movable die plate. A rod for moving the movable die plate forward and backward with respect to the fixed die plate, and a rod at the other end of the rod which is slidably inserted into the boost cylinder and whose inside is divided into a bottom chamber and a cylinder chamber. A piston portion, a cylinder portion that opens in the axial direction at the rear end portion of the rod, is slidably inserted into the piston portion, and one end of which is attached to the bottom portion of the boost cylinder, and the center of the ram. Axially An open passage formed through the through hole, and a prefill valve configured to cut off the communication between the cavity of the mold clamping cylinder and the oil tank, when moving the movable die plate backward with respect to the fixed die plate, By forming a differential circuit so as to introduce the pressure oil of the cylinder portion in the boost cylinder rod into the cylinder chamber of the boost cylinder, the machining cost is greatly reduced by eliminating the inner diameter machining of the mold clamping cylinder, By installing the pre-fill valve on the rear side surface of the mold clamping cylinder downward, it is possible to reduce the total length of the device and the installation floor area,
At the same time, it has an excellent effect that the mold opening / closing speed can be made the same and the mold opening force can be increased.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the spirit of the present invention. Is.

[Brief description of drawings]

1 shows an embodiment of a mold clamping device of the present invention, FIG. 1 (a) is a cross-sectional view of a main part of the mold clamping device, and FIG. 1 (b) is a partial cross-sectional view of the mold clamping device. It is the whole side view shown.

FIG. 2 shows another embodiment of the mold clamping device of the present invention, FIG. 2 (a) is a cross-sectional view of a main part of the mold clamping device, and FIG. 2 (b) is a partial cross-sectional view of the mold clamping device. It is a whole side view showing.

FIG. 3 shows another embodiment of the mold clamping device of the present invention, FIG. 3 (a) is a sectional view of a main part of the mold clamping device, and FIG. 3 (b) is a partial sectional view of the mold clamping device. It is a whole side view showing.

FIG. 4 shows another embodiment of the mold clamping device of the present invention, FIG. 4 (a) is a sectional view of an essential part of the mold clamping device, and FIG. 4 (b) is a partial cross-sectional view of the mold clamping device. It is a whole side view showing.

FIG. 5 shows a conventional mold clamping device, FIG. 5 (a) is a cross-sectional view of a main part of a booster ram type mold clamping device, and FIG.
FIG. 6 is a sectional view of a main part in which an auxiliary cylinder is provided separately from the mold clamping cylinder.

[Explanation of symbols]

 10 mold clamping cylinder 12 mold clamping ram 14 rapid feed ram 16 prefill valve 18 auxiliary cylinder 20 fixed die plate 22 mold clamping cylinder 24 tie bar 25 sliding plate 26 moving die plate 28 mold clamping ram 30 cavity (A chamber) 36 bottom chamber 38 Cylinder chamber (C chamber) 40 Boost cylinder 42 Rod 41 Piston portion 43 Cylinder portion (D chamber) 44 Ram 45 Open hole passage 46 Hydraulic tank 47a First rod 47b Second rod 48 Prefill valve 50 A port 54 C Port 56 Bottom chamber (B chamber) 57 Boost cylinder 58 B port 60 Boost ramp

Claims (4)

[Claims] 1. A movable die plate is fixed to one end of a mold clamping ram inserted in a mold clamping cylinder, and the movable die plate is guided and supported by a plurality of tie bars which connect the mold clamping cylinder and the fixed die plate. In the mold clamping device configured to move back and forth with respect to the fixed die plate, the mold clamping device inserts the mold clamping ram loosely and seals the outer periphery of the ram on the opening side so that the mold clamping device is slidably inserted. A mold clamping cylinder in which a cavity is formed between the ram end and the bottom,
A rod that is provided to be movable forward and backward by a boost cylinder fixed to the mold clamping cylinder and has one end locked to a movable die plate to move the movable die plate forward and backward with respect to the fixed die plate, and the other end of the rod. There is a piston part which is slidably inserted into the boost cylinder to define the interior thereof into a bottom chamber and a cylinder chamber,
A ram having an axially opening cylinder portion formed at the rear end portion of the rod, slidably fitted therein, and having one end attached to the bottom portion of the boost cylinder, and a piercing hole through the ram in the direction of the central axis thereof. A mold clamping device, which comprises a pre-filled valve that opens and closes the cavity of the mold clamping cylinder and the oil tank. 2. A movable die plate is fixed to one end of a mold clamping ram inserted in the mold clamping cylinder, and the movable die plate is guided and supported by a plurality of tie bars which connect the mold clamping cylinder and the fixed die plate. In a mold clamping device configured to move back and forth with respect to a fixed die plate, the mold clamping device inserts a mold clamping ram loosely and seals the outer periphery of the ram on the opening side so that the mold is slidably inserted. A mold clamping cylinder with a cavity formed between the end of the clamping ram and the bottom, and a boost cylinder fixed to the mold clamping cylinder are provided so as to be able to move forward and backward, and one end of the cylinder is locked to the movable die plate. A first rod that moves back and forth with respect to the fixed die plate, and at the other end of the first rod, the rod is slidably inserted into the boost cylinder, and the inside thereof serves as a bottom chamber. A piston portion defined in the cylinder chamber, and a first end of the piston portion opposite to the first rod, the other end of which is connected on the same axis as the first rod so as to project to the outside of the boost cylinder. A mold clamping device comprising a second rod and a pre-fill valve for blocking communication between the cavity of the mold clamping cylinder and the oil tank. 3. A movable die plate is fixed to one end of a mold clamping ram inserted into the mold clamping cylinder, and the movable die plate is guided and supported by a plurality of tie bars which connect the mold clamping cylinder and the fixed die plate. In a mold clamping device configured to move back and forth with respect to a fixed die plate, the mold clamping device inserts a mold clamping ram loosely and seals the outer periphery of the ram on the opening side so that the mold is slidably inserted. A mold clamping cylinder in which a cavity is formed between the end and the bottom of the clamping ram, and a boost cylinder that opens in the axial direction is formed in the rear end of the mold ram, and one end of the cylinder is the bottom of the cavity. And a boost ram whose outer circumference is inserted in the boost cylinder and an auxiliary cylinder fixed to the mold clamping cylinder, and one end of which is locked to the moving die plate. A rod for moving the movable die plate forward and backward with respect to the fixed die plate, and a rod at the other end of the rod which is slidably inserted into the auxiliary cylinder and whose inside is divided into a bottom chamber and a cylinder chamber. A mold clamping device comprising: a piston part formed by the mold; and a prefill valve for blocking communication between a cavity of the mold clamping cylinder and an oil tank. 4. A movable die plate is fixed to one end of a mold clamping ram inserted in the mold clamping cylinder, and the movable die plate is guided and supported by a plurality of tie bars which connect the mold clamping cylinder and the fixed die plate. In a mold clamping device configured to move back and forth with respect to a fixed die plate, the mold clamping device inserts a mold clamping ram loosely and seals the outer periphery of the ram on the opening side so that the mold is slidably inserted. A mold clamping cylinder having a cavity formed between the end of the clamping ram and the bottom and a boost cylinder fixed to the fixed die plate are provided so as to be able to move forward and backward, and one end of the movable die plate is locked to the movable die plate. A rod for advancing and retreating with respect to the fixed die plate, and at the other end of the rod, the rod is slidably inserted into the boost cylinder and the inside thereof is a bottom chamber and a cylinder. A mold clamping device comprising a piston part defined in a chamber and a pre-fill valve for blocking communication between the cavity of the mold clamping cylinder and the oil tank.