JPS6112316A - Mold clamping mechanism - Google Patents

Abstract

PURPOSE:To make it possible to shortly constitute a mold clamping mechanism by eliminating the necessity for providing a hydraulic tank to the outside and dispensing with suction and exhaust valves, by a method wherein the interior of a mold clamping ram is utilized as the hydraulic tank in the side of a mold clamping cylinder and a piston head is also used as the opening and closing member of an oil chamber and a booster ram is further internally mounted over the mold clamping ram and the mold clamping cylinder. CONSTITUTION:A mold clamping ram 1 is formed so as to be made hollow and the interiors of the mold clamping ram 1 and a mold clamping cylinder 2 are communicated in a freely openable and closable manner by the piston head 13 provided to the rear end of the ram in a freely movable manner to form an oil tank 16 in the mold clamping ram 1 while an idler piston 17 equipped with a quick feed oil chamber C and a piston 18 is provided to the oil tank 16 to partion the oil tank 16 into two oil chambers E, D and a booster ram 3 is arranged over the oil chamber of the piston 17 and the rear end wall of the mold clamping cylinder 2. By this structure, a mold clamping mechanism is shortly constituted and internal oil pressure resistance at the opening and closing time of the mold is extremely reduced while the high speed movement of the mold clamping ram is enabled by a slight supply amount of oil and the strong mold clamping of the mold can be performed by the large diameter mold clamping ram.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mold clamping device used in a synthetic resin molding machine, and particularly to a hydraulically operated mold clamping mechanism equipped with a rapid feed means.

(Prior art) In order to eliminate hydraulic resistance during mold opening/closing operations, a mold clamping mechanism in which pressure oil in two oil chambers of a mold clamping cylinder is alternately discharged from a circulation hole provided in a piston was developed in 1973. 24020
This method is disclosed in Japanese Patent Application Laid-Open No. 50-128755, etc.

In this conventional mold clamping mechanism, in order to make the volumes of the two oil chambers almost equal, a piston rod of the same diameter is inserted into the mold clamping cylinder, and an opening/closing member for the flow hole inserted through the piston is connected from the outside. It is configured to be operated by hydraulic oil.

(Problems to be Solved by the Invention) In the above-mentioned conventional mechanism, the opening/closing member operated by external hydraulic pressure is provided in the piston, which makes the structure of the piston complicated, and the opening/closing member is internally installed. Therefore, the mold clamping cylinder is formed longer. Moreover, since one of the piston rods or a booster ram must be protruded from the rear end of the mold clamping cylinder, the mold clamping mechanism becomes even longer. There are problems in that the piston rod cannot be formed with a large diameter and the mold cannot be opened and closed at high speed.

This invention was devised to eliminate the problems of the conventional mechanism described above, and its purpose is to shorten the mold clamping mechanism, minimize internal hydraulic resistance when opening and closing the mold, and use only a small amount of oil. It is an object of the present invention to provide a mold clamping mechanism with a new configuration, which enables high-speed movement of a mold clamping ram by supplying the supply, and can perform powerful mold clamping with a large-diameter mold clamping ram.

(Means for Solving the Problems) The feature of the present invention according to the above-mentioned objects is that the mold clamping ram is formed hollow, and the inside of the mold clamping ram and the inside of the mold clamping cylinder are movable at the rear end of the ram. The inside of the mold clamping ram is connected to open and close via a provided piston head, and the inside of the mold clamping ram is used as an oil tank.The oil tank is equipped with a floating piston equipped with an oil chamber for rapid feed and a piston, and the oil tank is divided into two oil chambers. A booster ram is provided between the oil chamber of the piston and the rear end wall of the mold clamping cylinder.

(Function) In the mold clamping mechanism with the above configuration, when pressure oil is supplied to the mold opening side oil chamber of the mold clamping cylinder, the idle piston in the mold clamping ram moves due to pressure oil from the booster ram, and the oil When the pressure oil in the tank is pressurized, the piston head of the mold clamping ram is opened by the hydraulic pressure, and at this time, the mold clamping side oil chamber of the mold clamping cylinder communicates with the oil tank, and a small amount of oil is released. The mold clamping ram moves at high speed.

This will be explained in more detail with reference to illustrated embodiments.

(Example) In the figure, 1 is a mold clamping ram, 2 is a mold clamping cylinder, and 3 is a booster ram. Further, the mold clamping cylinder 2 is connected to one fixed platen 5.

The mold clamping ram 1 is formed hollow by a cylindrical body 11 whose outer diameter is slightly smaller than the inner diameter of the mold clamping cylinder 2, and the rear end of the ram has an opening 12 in the center. A piston head 13 which is divided into oil chambers A and B is provided with a pin 14 so as to be movable in the axial direction by hydraulic pressure, and to be movable together with a return spring 14a.

The piston head 13 has a peripheral edge 13a that is loosely fitted into a step around the rear end of the ram, and an opening 1 that is in contact with the rear end surface of the ram.
2, and the disc body 13b is provided with a goose ram insertion hole and a communication hole 15 at required positions.

Inside the mold clamping ram 1, an oil tank 1 is provided which stores the pressure oil in the oil chamber B of the mold clamping cylinder 2 when the mold is opened, through communication between the opening 12 and the circulation hole 15 of the piston head 13.
It is formed into 6.

This oil tank 16 is connected to an oil chamber E having a sufficient volume to store the pressure oil in the oil chamber B and other oil chambers by a floating piston 17 having an oil chamber C for rapid feed in the center in the axial direction. The oil chamber C is still equipped with a piston 18 for rapid feed. This piston 18 extends from the rear end wall 2a of the mold clamping cylinder 2 to the disc body 13b and the opening 12.
The floating piston 17 is connected to the tip of the booster ram 3 provided in the oil chamber C by penetrating through and connected to the tip of the booster ram 3 provided in the oil chamber C, and moves the floating piston 17 toward the rear end of the ram by pressure oil supplied from the booster ram 3 to the oil chamber C. The oil pressure in oil chamber E is transferred to the mold clamping cylinder/20 oil chamber B.
It has the effect of supplying

Reference numeral 19 denotes a safety valve provided on the floating piston 17, which is used to shut down the two oil chambers when the pressure in the oil chamber E becomes abnormally high.

E is communicated to allow the pressure oil in the oil chamber E to flow out into the oil chamber.

21 is a switching valve provided in the hydraulic circuit from the pulp addition to the booster ram 3; This is the installed mold.

Next, the operation will be explained.

Fig. 1 (mold closed state) In the mold open state shown in Fig. 3, the switching pulp nod,
21 to the state shown in FIG. Pressure oil is supplied to the oil chamber C, which has contracted.

As pressurized oil is supplied, the floating piston 17 moves within the oil tank 16 of the mold clamping ram 1 toward the rear end of the ram, that is, toward the right in the drawing. Then, the pressure oil in the oil chamber E is pressurized, and the pressure oil flows out from the opening 12 and the open communication hole 15 of the piston head 13 to the oil chamber B of the mold clamping cylinder 2, and closes the mold clamping ram 1. Pressure is applied in the left direction in the drawing. Due to this operation, the mold clamping ram 1 continues to move until the floating piston 17 stops.

At this time, the amount of movement of the mold clamping ram 1 is larger on the mold clamping ram side due to the difference between the cross-sectional area of the mold clamping ram 1 and the cross-sectional area of the floating piston 17. Since the cross-sectional area of is formed smaller, the mold clamping ram 1 is able to move at high speed in the mold closing direction with a small amount of oil supplied from the booster ram 3 to the oil chamber C.

FIG. 2 (mold clamping state) When the mold 22 is closed by the movement of the mold clamping ram 1, the switching valve 21 is operated to connect the hydraulic circuit of the booster ram 3 to the tank side, and the hydraulic circuit of the booster ram 3 is connected to the tank side. The supply of pressure oil to the oil chamber C is stopped, and the hydraulic resistance in the oil chamber C is removed. At this time, the pressurization of the piston head 13 by the pressure oil from the oil chamber E is also removed, and the piston head 13 is The ram is pushed back toward the rear end side by the return spring 14a, and the opening 12 is closed due to the contact between the ram rear end wall and the disk body 13b, and the oil chamber B of the mold clamping cylinder 2 and the oil chamber E of the mold clamping ram 1 are closed. is blocked.

Thereafter, the hydraulic circuit of the oil chamber B is switched to the pump P side by operating the switching pulp nod, and pressure oil is supplied to the oil chamber B to pressurize the mold clamping ram 1. As a result, the mold n is
The mold is strongly clamped between the mold and the movable platen 6.

Fig. 3 (Mold open state) Next, leave the switching valve 21 as it is and operate only the switching valve to connect the hydraulic circuit of the oil chamber A to the pump P side, and at the same time connect the hydraulic circuit of the oil chamber B to the pump P side. is connected to the tank side, and pressurized oil is supplied to the oil chamber A with the hydraulic resistance in the oil chamber B removed in the same manner as the oil chamber C above.

The pressure oil supplied to the oil chamber A first passes through the piston head 1.
3, the piston head 13 is pressed against the spring 14.
Press against. This makes piston head 1? moves to the position where it hits the head of the bottle 148, and the disk body 1
3b is separated from the rear end surface of the ram to open the opening 12.

Therefore, the oil chamber B communicates with the oil chamber E through the communication hole 15 of the disc body 13'b through the gap between the rear end surface of the ram and the disc body 13b.

The pressure oil supplied to the oil chamber A further presses the piston head 13. Since the piston head 13 and the rear end of the ram are connected by the pin 14, the piston head 13
3, the mold clamping ram 1 also moves in the mold opening direction, that is, to the right in the drawing.

Further, the pressure oil in the oil chamber B flows into the oil chamber E between the rear end of the ram generated by the movement of the mold clamping ram 1 and the floating piston 17 and is stored therein. The floating piston 17 is pressurized to move the floating piston 17 to the position shown in the figure.

Figure 4 shows the operating state of the safety valve 19, in which the switching pulp application malfunctions during mold opening, and the oil chamber B is connected to the inlet P side, and pressure oil is supplied to the oil chamber B. When the piston head 13 is closed and the mold clamping ram 1 is pressurized, the pressure oil stored in the oil chamber E is pressurized by the mold clamping ram 1.
Press the floating piston 17. However, the suppressed movement of the floating piston 17 is limited to the position where the piston 18 touches the end of the oil chamber C, and even beyond that position, the clamping ram 1
When the pressure becomes higher than the spring pressure of the safety valve 19, the safety valve 19 automatically opens and releases the pressure oil into the oil chamber, and further the pressure oil flows into the tank and enters the oil chamber E.
This reduces the pressure in the oil chamber E and prevents damage to the machine due to an abnormal increase in pressure in the oil chamber E.

(Effects of the Invention) As described above, this invention utilizes the inside of the mold clamping ram as a pressure oil tank on the mold clamping cylinder side, so there is no need to provide an external pressure oil tank, and the piston head is Since it is also used as a chamber opening/closing member, there is no need for intake/exhaust valves. Furthermore, since the booster ram is installed internally between the mold clamping ram and the mold clamping cylinder, the mold clamping mechanism can be configured in a short length.
The rapid feed means can be simplified, such as requiring only one hydraulic path in the booster ram. Moreover, it has many features such as the mold clamping ram can be made large in diameter, the internal pressure oil can be moved quickly, and the mold can be opened and closed at high speed by supplying a small amount of pressure oil.

[Brief explanation of the drawing]

The drawings show one embodiment of the mold clamping mechanism according to the present invention, in which Fig. 1 is a longitudinal sectional front view when the mold is opened, Fig. 2 is a longitudinal sectional front view when the mold is closed, and Fig. 3 is a longitudinal sectional front view when the mold is closed. FIG. 4 is a longitudinal sectional front view when the safety valve is activated. 1... Mold clamping ram 2... Mold clamping cylinder 3... Booster ram 12... Opening 13... Piston head 13a...
Peripheral part 131)...Disc body

Claims (1)

[Claims] The mold clamping ram is formed hollow, and the inside of the mold clamping ram and the mold clamping cylinder are communicated with each other by a piston head that is movably installed at the rear end of the ram, allowing the inside of the mold clamping ram to function as an oil tank. The oil tank is provided with an idle piston having an oil chamber for rapid feed and a piston to divide the oil tank into two oil chambers, and a booster ram is installed between the oil chamber of the piston and the rear end wall of the mold clamping cylinder. A mold clamping mechanism characterized by being provided with.