JPH0233475B2 - KATAJIMESOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a direct pressure mold clamping device used in injection molding machines, die casting machines, and the like.

(Prior art) This type of injection device requires high-speed mold opening/closing and strong mold clamping force, so a structure in which a booster ram for rapid feed is inserted into the mold clamping ram is used. There is. In this mold clamping device, pressure oil is supplied to the small cylinder part of the mold clamping ram through an oil passage provided in the booster ram to open and close the mold at high speed. Oil is supplied from the suction tank via the opened prefill valve. After the mold is closed, the prefill valve is closed, and pressurized oil is supplied to the oil chamber at the rear of the mold clamping ram to perform high-pressure mold clamping.

(Problems to be Solved by the Invention) In such a mold clamping device, when transitioning to high pressure mold clamping, pressure is increased from a negative pressure state to high pressure by supplying pressurized oil, so there is a problem that it takes time to increase the pressure. Since a large volume of oil moves between the tank and the tank during high-speed opening and closing, air entrainment and shock are likely to occur, making high-speed operation difficult and requiring a large-capacity tank.

Further, when designing a pre-fill valve, a lot of knowledge is required to solve the above-mentioned problems, and the structure and control thereof are also complicated.

Therefore, a mold clamping device (Special Publication No. 52-15627, Japanese Patent Publication No. 15627, No. 15627, Japanese Patent Publication No. 15627, No. 15627, Japanese Patent Publication No. 15627, No. 15627, No. 15627, Special Publication No. 15627)
No. 24614) was developed.

However, due to the structure of the above mold clamping device, the total length of the mold clamping device is more than double the mold clamping stroke used, resulting in an increase in size, weight, and cost. There was a problem.

This invention was devised to solve the above problems, and its purpose is to:
To provide a new mold clamping device which can operate at high speed without increasing the length of the entire device and can prevent air entrainment and generation of shock that tend to occur during high-speed mold opening/closing.

(Means for Solving the Problems) This invention for the above-mentioned purpose forms a mold clamping ram in a mold clamping cylinder hollow, and a double pipe structure is quickly fed from the rear of the mold clamping cylinder to the center of the interior of the mold clamping ram. By inserting the cylinder, the outer pipe of the rapid-forwarding cylinder communicates the rear oil chamber of the cylinder with the inside of the mold clamping ram, and the rear end of the outer pipe in the rear oil chamber of the cylinder is provided with a circulation port and a suction tank passage. The above problems are solved by connecting a high-pressure switching piston that opens and closes between the suction tank passage and the rear oil chamber of the cylinder.

(Function) In the above configuration, when the mold clamping cylinder moves forward together with the movable plate at high speed due to the pressurized oil fed to the rapid-feeding cylinder, the oil in the mold clamping ram flows through the outer pipe due to the opening of the high pressure switching piston and flows into the oil chamber at the rear of the cylinder. During high-speed retraction, oil in the oil chamber at the rear of the cylinder flows into the mold clamping ram and is stored there.

(Example) In the figure, 1 is a mold clamping cylinder, which has a large-diameter mold clamping ram 2 with a movable platen 3 at its tip inside, and a cylinder rear oil chamber 4 communicating with a suction tank 5 in its rear end. It's summery.

In the center of the mold clamping ram 2, a double-tube structure fast-feeding cylinder 6 is inserted from the rear end of the mold clamping cylinder 1. Flow ports 7 and 8 are bored at both ends of the outer tube 6a of the rapid-feeding cylinder 6, and the oil chamber 9 in the mold clamping ram 2 and the rear oil chamber of the cylinder are connected between the outer tube 6a and the inner tube 6b. A passage 10 communicating with 4 is formed. Further, a piston 11 connected to the movable platen 3 is inserted into the inner tube 6b.

The cylinder rear oil chamber 4 has a high pressure switching piston 12 that connects the circulation port 8 and the suction tank and opens and closes the suction tank 5 and the cylinder rear oil chamber 4.
is fitted around the outer circumference of the outer tube 6a, and the rear end of the high pressure switching piston 4 is connected to the rapid feed cylinder 6.
It is located in an oil chamber 13 provided by forming a stepped portion around the rear end portion. Also, between the stepped portion and the inside of the high pressure switching piston is an oil chamber 13a (see Fig. 2) that moves the high pressure switching piston 4 backward in the closing direction.

In the example shown in FIG. 3, the suction tank 5 is integrally provided around the rear end of the mold clamping cylinder 1.

In the figure, 14 is a valve device for the high-pressure switching piston, 15 is a valve device for high-speed mold opening/closing, 16 is a valve device for mold clamping, and 17 is a partition plate on the inner diameter part of the mold clamping ram 2. The chamber communicates with the atmosphere.

Next, the mold opening/closing operation and the mold clamping operation will be explained.

In the state shown in FIG.
When pressure oil is supplied to the piston 11, the piston 11 is pressed and the mold clamping ram 2 moves forward together with the movable platen 3 at high speed in the mold closing direction. With this movement, the oil in the oil chamber 9 in the mold clamping ram flows into the passage 10 from the communication port 7 and further flows out into the cylinder rear oil chamber 4. Further, the insufficient amount of oil caused by the difference in volume between the two oil chambers is sucked up from the suction tank 5, thereby preventing negative pressure in the cylinder rear oil chamber 4.

When the high-speed mold closing by the fast-forwarding cylinder 6 is completed, when the valve device 14 is switched from the side a to the side b, the high-pressure switching piston 12 is turned off as shown in FIG.
is retreated, the outlet 8 communicates only with the suction tank 5, and the passage between the cylinder rear oil chamber 4 and the suction tank 5 is closed. Therefore, the valve device 16 is switched from the a side to the b side to send oil to the cylinder rear oil chamber 4.
Perform strong mold clamping. At this time, the oil in the oil chamber ram 9 is returned to the suction tank 5 via the passage 10 by an amount corresponding to the retightening stroke.

Next, the valve device 14 is placed on the a side, and the valve device 15 is
When the pressure oil is sent to the oil chamber 13 by switching the valve device 16 to the b side and the valve device 16 to the a side, the high pressure switching piston 12 moves forward to open the cylinder rear oil chamber 4 and the passage of the suction tank 5. Further, the cylinder front oil chamber 4a is pressurized, and a high pressure mold opening occurs there.

Therefore, when the valve device 15 is switched to the a side, a differential circuit is formed between the inside of the fast-feeding cylinder and the cylinder front oil chamber 4a, and the mold clamping ram 2 retreats at high speed together with the movable platen 3, and the high-speed mold A gap occurs. At this time, the oil in the cylinder rear oil chamber 4 is
It flows into the passage 10 from the oil passage 10, and further flows into the oil chamber 9 from the flow port 7.
The excess oil flows into the mold clamping ram 2 and is stored in the mold clamping ram 2, and excess oil is pushed out to the suction tank 5.

(Effects of the Invention) As described above, the present invention configures the rapid feed cylinder with a double-structured pipe body, and uses the outer pipe 6a to connect the oil chamber 9 of the mold clamping ram 2 and the rear oil chamber 4 of the cylinder.
The high-pressure switching piston 12 on the rear oil chamber side of the cylinder allows oil to alternately flow through both oil chambers during high-speed opening/closing. The amount is the difference in volume between the two oil chambers, and since the amount is extremely small, the suction tank can be downsized.

In addition, it can operate at high speed without air entrainment or shock, and because the mold clamping ram is formed with a large diameter and has an oil chamber inside, the mold clamping cylinder does not become particularly long, and the entire device can be Can be summarized compactly.

[Brief explanation of drawings]

The drawings show an embodiment of the mold clamping device according to the present invention. Fig. 1 is a sectional view when the mold is opened, Fig. 2 is a sectional view of the main part when the mold is closed, and Fig. 3 is a sectional view of another embodiment. FIG. 1...Mold clamping cylinder, 2...Mold clamping ram, 4...
Cylinder rear oil chamber, 5... Suction tank, 6... Rapid feed cylinder, 6a... Outer pipe, 7, 8... Distribution port, 9, 13, 13a... Oil chamber, 10... Passage,
12...High pressure switching piston, 14, 15, 16...
...Valve device.

Claims (1)

[Claims] 1 The mold clamping ram inside the mold clamping cylinder is formed hollow,
A double-tube structure fast-feeding cylinder is inserted into the center of the mold-clamping ram from the rear of the mold-clamping cylinder, and the outer tube of the fast-feeding cylinder communicates the cylinder rear oil chamber with the inside of the mold-clamping ram. A high-pressure switching piston is fitted around the rear end of the cylinder rear oil chamber to connect the flow port and the suction tank passage, and to open and close between the suction tank passage and the cylinder rear oil chamber. mold clamping device.