JPH0220411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection molding machine equipped with a hot runner separation mechanism for double-sided molds such as stack molds, which has no resin leakage from the separation part, has excellent durability, and is easy to maintain. The present invention relates to a valve device for an injection molded disconnection hot runner, which is characterized by the following.

Conventionally, when this type of injection molding machine uses a long nozzle, a cylindrical protrusion that is longer than the center of the thickness of the mold comes out, which causes problems in dropping and taking out the product.

In addition, the touch part with the molding machine separates at the same time as the mold opens, and the touch surface gradually enters the mold.
Protective equipment such as a cover was also required to prevent resin from leaking from entering the mold.

In addition, in the conventional separation structure, a protruding cylinder containing floating sesame that moves forward with a spring force is split in the center, and each floating sesame protrudes at the same time as the mold opens, blocking the resin path and preventing resin leakage. However, with this structure, there is no way to prevent resin leakage due to the resin path that is created when floating sesame seeds collide with each other, and therefore there are significant restrictions on the position in which the device can be installed in this example. Ta.

Furthermore, leaked resin is trapped, causing damage to the mold, and the resin adheres to band heaters, etc., which significantly impairs their durability and service life.

In other words, in the conventional example, a long cylinder stroke is required from the movable side, and when used for a long period of time, the eccentric nozzle seals the resin path on the stationary side with a bevel, and the movement of the eccentric nozzle is forcibly returned by molding. There were problems with maintenance.

This invention was made to improve the problems of the conventional structure described above, and in injection molds, the resin that is the material of the molded product must not leak from the mold other than the gate. Regarding stack molds, depending on the mold operation and mold structure, the resin path must be moved at the same time as the mold is opened, or the resin path must be separated at the same time as the mold is opened. To provide a valve device for an injection molded disconnection hot runner which has a structure in which a resin path is separated, has no resin leakage, can withstand a long life, and is easy to maintain.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view of the valve device for a hot runner according to the present invention, showing a state in which mold clamping is completed. In the figure, the fixed casing 1 and the movable casing 2 can be separated at a separation part P, and the fixed casing 1 and the movable casing 2 are equipped with band heaters 3a and 3b on their outer peripheries to keep the casing in a predetermined position. Maintains temperature.

A fixed hot runner 4 is fixed to the upper part of the fixed casing 1, and the resin paths 1a and 4a communicate with each other.

Further, a seal rod 5 is fitted into the fixed casing 1 from above the fixed hot runner 4, and seals off the tip nozzle 1b of the fixed casing 1 via a spring 6.

On the other hand, a movable hot runner 7 is fixed below the movable casing 2, and the resin paths 2a and 7a communicate with each other.

Further, from below the movable hot runner 7 to which the movable casing 2 is fixed, a cylinder rod 8 is inserted.
is inserted into the cylinder 9, and its vertical movement is controlled via a cylinder stroke adjustment rod 10 mounted inside the cylinder 9.

The cylinder 9 has an oil port a that is press-fitted with hydraulic pressure to lower the cylinder rod 8, an oil port b that is press-fitted with the hydraulic pressure that raises the cylinder rod 8, and a hydraulic pressure that is press-fitted to lower the cylinder stroke adjustment rod 10. There are provided an oil port (c) for press-fitting the cylinder stroke adjustment rod 10, and a foil port (d) for pressurizing the hydraulic pressure to raise the cylinder stroke adjustment rod 10.

Next, the operation of the hot runner valve device configured as described above will be described in detail. First of all
In the figure, before entering the mold clamping state, oil port a,
Hydraulic pressure is applied to d, but cylinder rod 8
Due to the difference in diameter between the cylinder stroke adjusting rod 10 and the cylinder stroke adjusting rod 10, the cylinder stroke adjusting rod 10 overcomes the cylinder rod 8 and is clamped in the state shown in FIG.

At the same time as the mold tightening, the oil pressure in the oil port d is removed, and the cylinder rod 8 is lowered as shown in FIG. 2, and the seal rod 5 is held by the spring 6 in a state where the tip nozzle 1b is closed.

Next, injection is started in this state, and the injected resin has no escape within the closed resin paths 1a and 4a, and pushes up the seal rod 5 against the spring 6, opening the resin path of the tip nozzle 1b, and opening the third resin path. The state shown in the figure is established, and the resin flow is communicated with the resin paths 2a and 7a of the movable casing 2 and the movable hot runner 7. When the injection is completed, as shown in FIG. 4, hydraulic pressure is injected from the oil ports b and d, pushing the cylinder rod 8 upward and filling the resin path 2a of the movable casing 2 and the tip nozzle 1b of the fixed casing 1. The resin is also pushed up into the resin channel 1a of the fixed casing 1.

After that, as shown in Figure 1, oil ports a and d are
Hydraulic pressure is applied to the cylinder rod 8 to return it to its normal state, and following this movement, the seal rod 5 is lowered by the spring 6. After the tip nozzle 1b of the fixed casing 1 and the tip of the fixed casing 2 are completely sealed in this way, both molds are opened at the separation portion P.

In addition, in the above configuration, the operation of the seal rod fitted into the fixed side casing and hot runner is pushed back by spring force and resin pressure.
The present invention is not limited to this, and a hydraulic cylinder or the like may be incorporated to forcibly operate the system.

In addition, the cylinder is a two-stage piston, and the cylinder rod and cylinder stroke adjustment rod have three stages of stroke, but it is also possible to use a regular cylinder and stop the position at three stages by detecting the flow rate or stroke. It goes without saying that this is possible and can be set as appropriate.

As described above in detail, the injection molded breakaway hot runner valve device according to the present invention has a fixed casing and a movable casing fixed to the opposing surfaces of a fixed hot runner and a movable hot runner, respectively, and a fixed casing fixed to the fixed hot runner from the opposite side. A seal rod is fitted and inserted, and the tip nozzle of the fixed casing is always closed off via a spring. Also, a cylinder is fixed on the opposite side of the movable hot runner to which the movable casing is fixed, and the cylinder rod inserted into this is fixed. The cylinder rod is arranged to move up and down through the movable hot runner, the movable casing, and the resin path of the fixed casing, and the cylinder rod is controlled by hydraulic pressure that is press-fitted from a predetermined oil port provided in the cylinder. In addition, there is no resin leakage from the separation part of the mold in injection molding, and there are advantages such as excellent durability and easy maintenance.

[Brief explanation of drawings]

1 to 4 are longitudinal cross-sectional views of essential parts showing the structure and operating state of a hot runner valve device according to an embodiment of the present invention. 1... Fixed casing, 1a... Resin road, 1b... Tip nozzle, 2... Movable casing, 2a... Resin road,
4...Fixed hot runner, 4a...Resin road, 5...Seal rod, 6...Spring, 7...Movable hot runner, 7a...Resin road, 8...Cylinder rod, 9...
Housing, 10... Cylinder stroke adjustment rod, a, b, c, d... Oil port.

Claims (1)

[Claims] 1. A fixed casing and a movable casing are respectively fixed to opposing surfaces of a fixed hot runner, and a seal rod is inserted into the opposite side of the fixed hot runner to which the fixed casing is fixed, and the tip nozzle of the casing is always sealed off via a spring. A cylinder is fixed on the opposite side of the above-mentioned movable hot runner to which the movable casing is fixed, and the cylinder rod fitted into the cylinder rod is arranged so as to move up and down through the resin path of the movable hot runner, movable casing, and fixed casing. A valve device for an injection molding cut-off hot runner, characterized in that the cylinder rod is controlled by hydraulic pressure that is press-fitted from a predetermined oil port provided in the cylinder.