JPH0233474B2 - SEIKEIKINOKATAKAIHEISOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a mold opening/closing device used in a molding machine for injection or die casting.

(Prior Art) An auxiliary cylinder type mold opening/closing device used as a mold opening/closing device of a molding machine for injection or die casting, as shown in FIG. 4, has a pair of fixed plates 1,
A mold clamping ram 6 of a mold clamping cylinder 5 attached to one fixed plate 1 and the mold clamping cylinder 5 are mounted on a movable platen 4 that moves using tie bars 3, 3 provided over two sections as a guide.
The auxiliary cylinder 7 is connected to the auxiliary piston 8 of the auxiliary cylinder 7, which has a smaller cross-sectional area than the auxiliary cylinder 7, and the molds 9 and 10 attached to the opposing surfaces of the other fixed platen 2 and movable platen 4 are opened and closed by the movement of the movable platen 4. Consists of structure.

To close the mold in such an apparatus, first, pressure oil is sent to the oil chamber 7a of the auxiliary cylinder 7, and the auxiliary piston 8 moves the movable platen 4 forward at high speed. At this time,
As the mold clamping ram 6 moves forward together with the movable platen 4, a negative pressure is created in the oil chamber 5a of the mold clamping cylinder 5, and oil in the oil tank is sucked in through a pre-fill valve (not shown). Then, just before the molds 9 and 10 are closed, the prefill valve is closed and the oil chamber 5 is closed.
By supplying pressure oil to a, the movable platen 4 moves forward at a low speed, and when the molds 9 and 10 are closed, the pressure oil acts on the entire area of the mold clamping ram 6 and the auxiliary piston 8, resulting in strong mold clamping. will be held.

When opening the mold, pressurized oil is supplied to the oil chamber 7b of the auxiliary cylinder 7, and the prefill valve is opened.
As a result, the movable platen 4 moves back at high speed while returning the oil in the oil chamber 5a of the mold clamping cylinder 5 to the tank via the prefill valve.

In that case, at the beginning of mold opening and near the completion of mold opening, the supply amount of pressure oil is reduced to slow down the mold opening speed.

(Problem to be Solved by the Invention) However, in the conventional device described above, mold opening is performed only by the auxiliary cylinder, so in order to increase the initial mold opening force, the diameter of the auxiliary cylinder must be increased. Increasing the cylinder diameter slows down the mold opening/closing speed and slows down the cycle.
Either you have to put up with either the mold opening force or the mold opening/closing speed being small, or you can set the diameter of the auxiliary cylinder large and use a pump with a large discharge capacity to satisfy both, and change the pump, motor, and hydraulic equipment. There was a problem of having to put up with an increase in running costs due to an increase in energy consumption.

(Means for Solving the Problems) The present invention, which aims to solve the above problems, is an auxiliary cylinder type mold in which a movable platen is reciprocated by an auxiliary cylinder with a small cross-sectional area and a clamping cylinder with a large cross-sectional area. The gist of the switchgear is that a cylinder that expands and contracts in the mold opening/closing direction is provided between the mold mounting surface of a movable platen with a movable mold and the mold mounting surface of a fixed mounting board with a fixed mold. It is something to do.

(Function) In the present invention with the above configuration, high-speed mold opening/closing is performed by a small-diameter auxiliary cylinder, strong mold clamping is performed by a mold clamping cylinder, and initial mold opening is performed by an auxiliary cylinder, a movable platen, and a fixed mold mounting. This is done by both cylinders installed between the board and the board.

(Embodiment) The embodiment shown in Fig. 1 is a case in which a pair of mold opening cylinders are provided in a mold opening/closing device having the same structure as the conventional device shown in Fig. 4, and the same parts are denoted by the same reference numerals. It shows.

The mold opening cylinders 11, 11 have a mold opening piston 12,
12 is provided facing the mold mounting surface of the movable platen 4.
The mold opening piston 1 is mounted on the mold mounting surface of the movable platen 4.
Receiving members 13, 13 are provided, with which the members 2, 12 are brought into contact.

In addition, the mold opening pistons 11, 11 and the receiving member 1
3 and 13 are preferably attached to the mold mounting surfaces of the fixed platen 2 and the movable platen 4 so as to be located on the extension line of the auxiliary piston 8.

The auxiliary cylinders 7, 7 are set to have a cross-sectional area necessary for high-speed mold opening/closing, and the mold opening cylinders 11,
11 is actuated by supplying pressure oil to the oil chambers 11a, 11a simultaneously with the retreat side operation of the auxiliary cylinders 7, 7, and is added to the retreat output of the auxiliary cylinders 7, 7 to generate a predetermined mold opening force. It is set.

Next, the operation will be explained.

In the mold opening state in which the mold opening pistons 12, 12 and the mold clamping ram 6 are retracted, pressure oil is supplied to the oil chambers 7a, 7a of the auxiliary cylinders 7, 7, as in the case of FIG. As a result, the auxiliary pistons 8, 8, the movable platen 4, the mold 10, and the mold clamping ram 6, which are integrated therewith, move forward at high speed to close the mold at high speed. Immediately before the molds 9 and 10 are completely closed, the prefill valve is closed and pressure oil is also supplied to the oil chamber 5a, so that the movable mold moves forward at low speed and closes at low speed, completely closing the mold. When the molds 9 and 10 are closed, pressure oil is applied to the entire area of the oil chambers 5a and 7a, and the molds are strongly clamped.

In this state, processes such as injection and filling into the mold cavity and cooling are performed, and then the mold opening process begins.

In the mold opening process, first, the oil chamber 5a, the oil chamber 7a, 7a
The pre-fill valve is opened to supply pressure oil to the oil chambers 11a, 11a and the oil chambers 7b, 7b. Therefore, the movable platen 4 is pulled back by the auxiliary pistons 8, 8, and the mold opening pistons 12,
After the molded product is released from the mold 9, the mold is opened at high speed by the operation of only the auxiliary cylinders 7, 7.

Immediately before the high-speed mold opening is completed, the amount of pressure oil supplied to the oil chambers 7b, 7b is reduced to slow down the mold opening, removing the shock caused by inertial force and completing the mold opening. After the mold opening is completed, the oil chambers 11b, 1 of the mold opening cylinders 11, 11
Pressure oil is supplied to 1b and the mold opening pistons 12, 12 are returned to their original positions.

The embodiment shown in FIGS. 2 and 3 is a mold opening/closing device for a rotary molding machine, and 21 is a machine base;
2 is a rotary disk rotatably provided on the top surface of the machine;
3 is a mold clamping cylinder located at the center inside the machine base 21, and is fixed to the machine base upper plate with the cylinder side at the top.
A mold clamping ram 24 is connected to a movable platen 25 inside the machine.

A movable plate 26 located above the rotary plate 22 is connected to the movable plate 25 by divers 27, 27 provided through the upper plate of the machine. Molds 8 and 29 are attached to the surface.

Also, between the machine top plate and the movable platen 25, there are a pair of auxiliary cylinders 30, 30 and auxiliary pistons 31, 3.
1 is arranged in parallel with the mold clamping cylinder 23 and the mold clamping ram 24, and the movable platen 25, together with the movable platen 26, is moved by the expansion and contraction of its auxiliary pistons 31, 31.
It is designed to move up and down.

On the mold forming side of the rotary plate 22 and the movable plate 26, there are mold opening cylinders 32, 32 at positions corresponding to the auxiliary cylinders 30, 30, and a mold opening piston 3.
3 and 33 are provided, and when the mold opening pistons 33, 33 are extended by the mold opening cylinders 32, 32 attached to the movable platen 26 side, the embodiment shown in FIG. Similarly, the movable platen 26 moves upward together with the mold 28, and the mold opens there. At this time, a pressing force toward the machine base 21 acts on the rotary disk side as a reaction force.

Although the mold opening piston in the embodiment is of a double acting type, it may be of a single acting spring return type. Furthermore, since the receiving member is provided to protect the movable platen and the rotary platen, it may be omitted depending on the case.

(Effects of the Invention) As described above, this invention allows high-speed mold opening and closing to be performed at extremely high speed using a small-diameter auxiliary cylinder, and moreover, strong mold opening has sufficient force due to the auxiliary cylinder and the mold-opening cylinder. Therefore, it is possible to secure the mold opening force and shorten the cycle time at the same time. In addition, since the mold opening cylinder operates only at the initial stage of mold opening, a short stroke is sufficient, and it does not interfere with installation or removal of the molded product, and the flow rate used is small, making it possible to upgrade pumps, motors, etc. do not need.

Furthermore, in the case of a rotary molding machine, the mold opens using a reaction force on the rotary disk side, unlike the usual case where the mold opening force is transmitted directly from the movable plate to the mold to open the mold. It has the advantage that it is not necessary to firmly support the rotary disk against the tensile force acting on the rotary disk through the mold, and the support structure can be simplified.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a first embodiment of a mold clamping device according to the present invention, FIG. 2 is a schematic sectional view of a second implementation row, FIG. 3 is a plan view thereof, and FIG. 4 is a conventional mold clamping device. FIG. 3 is a schematic cross-sectional view of the mold clamping device. 2... Fixed plate, 4... Movable plate, 5... Mold clamping cylinder, 6... Mold clamping ram, 7... Auxiliary cylinder, 8
...Auxiliary piston, 9,10...Mold, 11...
Mold opening cylinder, 12... Mold opening piston, 13...
Receiving member, 22...Rotary plate, 23...Mold clamping cylinder, 24...Mold clamping ram, 26...Movable plate, 28,
29... Mold, 30... Auxiliary cylinder, 31...
Auxiliary piston, 32... Mold opening cylinder, 33...
Mold opening piston, 34...receiving member.

Claims (1)

[Claims] 1. In an auxiliary cylinder type mold opening/closing device in which a movable platen is operated reciprocally by an auxiliary cylinder with a small cross-sectional area and a mold clamping cylinder with a large cross-sectional area, a mold mounting surface of a movable platen with a movable mold and a fixed mold. A mold opening/closing device for a molding machine, characterized in that a cylinder that expands and contracts in the mold opening/closing direction is provided between a mold mounting surface of a fixed mounting plate.