JPH0114414Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement in the structure of an injection mold.

(Prior Art) Conventionally, the parting surface of an injection mold has been designed and manufactured to satisfy two functions: a sealing function for molten resin and a function for receiving mold clamping force received from a molding machine. Figures 1 and 2 show an example of the state of the parting surface.
The fixed insert 1 constituting the fixed mold and the movable insert 2 constituting the movable mold are respectively formed with parting surfaces 1' and 2', and in the mold clamping state (Fig. 1), they fit tightly together. This prevents leakage of molten resin from the cavity 3 and serves to receive mold clamping force.

However, for injection molds that are subjected to mold clamping forces of several hundred tons, the surface width L of the parting surfaces 1' and 2' must be set quite large (30 mm or more). Due to this, various problems such as those described below have been raised.

That is, the number of man-hours for copying and setting increases, and the mold manufacturing cost increases. The mold manufacturing period becomes longer due to the increase in the number of processing steps.
It becomes difficult to ensure uniform alignment accuracy over the entire parting surface, and problems such as burrs are likely to occur. etc. This is a problem.

(Purpose of the invention) In view of the above-mentioned problems of the conventional technology, the present invention provides the parting surface with only a sealing function for the molten resin, and replaces the pressure receiving function of the mold clamping force with another part, thereby making it easier to copy in mold manufacturing. It is an object of the present invention to provide an injection molding mold that can greatly reduce the number of man-hours and setting man-hours, and furthermore, can easily ensure the precision of alignment of parting surfaces.

(Structure of the invention) This purpose is to form a parting surface with an extremely narrow surface width on the fixed mold and the movable mold, and to protrude a load receiving pin extending in the mold clamping direction around the parting surface of the movable mold. , and the fixed mold has a flat surface that can come into direct contact with the load receiving pin, and the parting surface has a sealing function and the load receiving pin has a pressure receiving function. This is achieved through type structure.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

FIGS. 3 and 4 show the main structure of an injection mold according to the present invention. In the same figure, 1
Reference numeral 1 denotes a fixed insert forming a fixed mold, 12 a movable insert forming a movable mold, and both have extremely narrow parting surfaces 11' and 12' having a surface width a, respectively. Also, the parting surface 1 of the movable insert 12
2', a plurality of flat surfaces 13, 1 are arranged in a multi-stage manner.
3... are formed, and a plurality of load receiving pins 14, 14... are fixed at appropriate locations with tightening bolts 15 in the mold clamping direction (up and down direction in the drawing). Furthermore, the fixed insert 11 is formed with a flat surface 16 that can come into direct contact with the load receiving pin 14 .

Here, the parting surfaces 11' and 12' are for sealing to prevent molten resin from leaking from the cavity 17 during injection molding, and their surface width is as follows:
As a result of various tests, if it exceeds 20 mm, the effects described below cannot be obtained, so it should be 20 mm or less, preferably 5 to 10 mm.
is set to the size of Furthermore, as a characteristic of the injection molding resin, the gap between the parting surfaces 11' and 12' during mold clamping (Fig. 3) is allowed to be about 0.02 mm, so in this example, a gap of about 0.02 mm was actively used. I'm trying to leave some space.

On the other hand, the load receiving pin 14 serves to receive the mold clamping force of the molding machine, and its outer diameter b and the number of pins installed are appropriately set so as to have a cross-sectional area sufficient to withstand the mold clamping force. Note that the shape is not limited to the illustrated circular cross-section, and may be, for example, rectangular in cross-section.

In addition, the length c of the load receiving pin 14, the flat surface 13
The base thickness e of the movable insert 12 on which the movable insert 12 is formed and the base thickness d of the fixed insert 11 on which the flat surface 16 is formed.
are processed with an accuracy of approximately 0.01 mm.

Although not shown in the drawings, force in the direction perpendicular to the mold clamping direction is dealt with by a conventional locking block.

With such a configuration, even when the mold is closed during injection molding (Fig. 1), the parting surfaces 11', 1
No mold clamping force is applied to 2', and the entire force is applied to the load receiving pin 14. Under this condition, even if the cavity 3 is filled with molten resin, the molten resin will not be absorbed by the parting surfaces 11', 1
2' completely prevents the leakage, making it possible to obtain a resin product without burrs.

(Effects of the invention) As explained above in detail, the injection mold according to the invention has only the function of sealing the molten resin on the parting surface, and the clamping force is determined by the load placed around the parting surface. It was designed to be received with a receiving pin, and the following effects were obtained by this.

Since the parting surface width can be set extremely narrow, the number of man-hours for copying and setting can be reduced, reducing mold manufacturing costs. Incidentally, compared to the conventional method, the number of man-hours for copying has been reduced by approximately 30%, the number of man-hours for setting has been reduced by approximately 70%, and mold costs have been reduced by approximately 15%.

In particular, by shortening the setting period, it has become possible to shorten the mold manufacturing period. Incidentally, compared to the past,
Setting time was reduced by 70% and mold making time was reduced by 10%.

It became easy to obtain uniform contact accuracy on the parting surface, and it was possible to prevent the occurrence of burrs, which is one of the molding defects.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main structure of a conventional injection mold, Fig. 2 is a perspective view showing the movable mold structure similar to Fig. 1, and Fig. 3 is a cross-sectional view showing the structure of the main part of a conventional injection mold. FIG. 4 is a cross-sectional view showing the main structure, and FIG. 4 is a perspective view showing the movable structure similar to FIG. 3. 11... fixed type (fixed insert), 12... movable type (movable insert), 11', 12'... parting surface,
14...Load receiving pin, 16...Flat surface.

Claims (1)

[Scope of utility model registration request] A parting surface with a surface width of 20 mm or less, preferably 5 to 10 mm, is formed on the fixed mold and the movable mold, and a load receiving pin extending in the mold clamping direction is provided protruding around the parting surface of the movable mold, and the fixed mold An injection mold structure characterized in that a flat surface is formed so as to be able to come into direct contact with the load receiving pin.