JP3663001B2 - Mold device for resin molded products - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold apparatus for a resin molded product, and more particularly to a mold apparatus for molding a cylindrical resin molded product whose one end is closed.
[0002]
[Prior art]
In a mold apparatus for molding a cylindrical resin molded product whose one end is closed, a cylindrical cavity is usually formed by inserting a slide pin into a space that defines the outer surface of the molded product. ing.
FIG. 7 shows an example a of a mold apparatus for molding a cylindrical body whose one end is closed, and a mold b formed in half (only one mold half is shown in the figure). )) Is formed with a cylindrical space d having an open end c, and a runner e extending into the space d from a direction perpendicular thereto.
[0003]
Further, a slide pin g having an insertion portion f having a diameter smaller than the diameter of the space d is slidably supported at a position coaxial with the space d, and the insertion portion f is inserted into the space d. A cylindrical cavity h with one end closed is formed. And a desired cylindrical body is shape | molded by injecting molten resin in the cavity h from this state.
[0004]
However, the slide pin g in this type of mold apparatus a inevitably has a cantilever structure, and injection of the molten resin is performed at a considerably high pressure, so that the slide pin g is inclined in the radial direction by this injection pressure. There is a problem of end.
If the slide pin g is tilted, the thickness of the molded product is uneven, and if it is severe, a fatal molding defect such as a hole in the peripheral wall may occur.
[0005]
Therefore, in this type of mold apparatus a, a method of injecting resin in a state where the ring i shown in FIG. 8 constituting a part of the molded product is fitted in the slide pin g in advance is employed.
The ring i has the same size as the required cross section of the cylindrical body, and is formed to have substantially the same dimension as the thickness of the blocking wall of the cylindrical body in the axial direction. The ring i is fitted into the insertion portion f of the slide pin g, and when the insertion portion f is inserted into the space d, the slide pin g is brought into contact with the inner peripheral surface of the space d as shown in FIG. It will be supported by the same support structure as the double bearing support.
[0006]
From this state, as shown in FIG. 10, when the molten resin j is injected into the cavity h, the ring i is moved to the end of the cavity h by the injection pressure of the resin j, and is integrated with the molten resin j. It constitutes the end wall of the molded product.
Note that a slit k is formed in the ring i so that the ring i can be easily attached to the slide pin g. Further, a step l is formed at an intermediate portion in the axial direction of the inner peripheral surface of the ring i, and is stably held by the resin j.
[0007]
[Problems to be solved by the invention]
However, the method using the ring i has various problems as follows. A separate mold for molding a special part called ring i and a molding process thereof are required, and this preliminary work is costly. In addition, it is necessary to attach the ring to the slide pin g for each injection operation, and this operation is inevitably dependent on human hands.
[0008]
In addition, even if the ring i is used, it is tilted slightly because the mounting is not performed correctly, or even if the mounting is performed correctly, it is tilted for some reason in the cavity h, and the movement stops halfway. In some cases, the pin g may not move to the end of the pin g, so that the molded product becomes defective.
Moreover, even if the above problems do not occur, the injected molten resin j and the ring i may not be integrated well, and the ring i may come off, and in any case, the yield is poor. Was inevitable.
[0009]
The present invention has been made paying attention to the above-mentioned conventional problems, and it is possible to reliably prevent the inclination of the slide pin without preparing special parts that constitute a part of the molded product. An object of the present invention is to provide a mold apparatus for a resin molded product capable of performing a stable molding operation.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a mold apparatus for a resin molded product of the present invention is a mold apparatus for a resin molded product having a cylindrical portion closed at one end, and the outer surface of the cylindrical portion of the resin molded product is A cavity to be defined, a slide pin that is inserted into the cavity and defines the inner surface of the cylindrical portion, a guide shaft that is coaxial with the cavity and has a tip surface that is located in the same plane as one end surface of the cavity, A support sleeve that is slidably fitted to the guide shaft and has at least a tip cross-sectional shape that is the same as that of one end of the cylindrical portion, and at least the tip of the support sleeve after mold closing and before injection of molten resin Drive means for moving to a forward position fitted at the tip of the slide pin, and the support sleeve is moved by the injection pressure when the molten resin is injected into the cavity. It is obtained so as to be withdrawal.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The details of the mold apparatus for a resin molded product according to the present invention will be described below according to the embodiment shown in the drawings.
In the embodiment shown in the drawings, the present invention is applied to a mold apparatus for taking and molding two cylindrical resin molded products.
[0012]
The holder 1 as a resin molded product will be described with reference to FIG.
This holder 1 (shown with a part cut away in the drawing) is for accommodating, for example, a rod-shaped liquid level sensor.
The holder 1 is composed of a cylindrical main portion 3 whose one end is closed by an end wall 2 and a flange 4 whose central portion is a position close to the other end of the main portion 3. A portion 3a on the other end side from the flange 4 of the main portion 3 has a slightly larger diameter than the other portion 3b, and a male screw 5 is formed on the outer peripheral surface of the portion 3a. Reference numeral 6 denotes a large-diameter portion located where the portion 3b and the flange 4 are continuous.
The two holders 1 are molded in a state where they are connected by the runner residual resin 7, and are separated by cutting off the runner residual resin 7 later.
[0013]
Next, the mold apparatus 15 will be described with reference to FIGS.
Reference numeral 17A denotes a fixed mold, and 17B denotes a movable mold. The two molds 17A and 17B constitute a pair of molds.
Reference numeral 19 denotes a parting surface of the fixed die 17A, 21 denotes a parting surface of the movable die 17B, and a cavity is formed to define the outer shape of the holder 1 on the parting surface 19 and the parting surface 21 to be joined together. A recess 23 is formed.
[0014]
The cavity forming recess 23 has a shape in which the outer shape of the holder 1 is divided into two at its axis. That is, in the cavity forming recess 23, a hook-like portion 23 a extending in the vertical direction indicates a portion corresponding to the main portion 3 of the holder 1, and the size of a semicircular arc that intersects the position near the lower end of the portion 23 a. The two grooves 23 b and 23 c indicate portions corresponding to the flange 4 and the large diameter portion 6.
Reference numeral 25 denotes a recess for forming a runner.
[0015]
Reference numeral 27 denotes a lower block of the fixed mold 17A. The lower block 27 protrudes from a position below the cavity forming recess 23 of the parting surface 19, and its upper surface is in the same plane as the lower end surface of the cavity forming recess 23. To position. In the lower block 27, a slide pin guide hole 29 leading to the cavity forming recess 23 is formed.
[0016]
Reference numeral 31 denotes a slide pin slidably supported in the slide pin guide hole 29. The slide pin 31 is moved to the insertion position shown in FIG. 3 by a driving means (not shown) when molding is performed, and in other cases, the slide pin 31 is entirely in the slide pin guide hole 29 as shown in FIG. Wait at
The outer shape of the insertion portion 32 of the slide pin 31, that is, the portion 32 located in the cavity forming recess 23 in the state where it is in the insertion position is the same as the inner shape of the holder 1.
[0017]
Reference numeral 33 denotes an upper block of the fixed mold 17A. The upper block 33 protrudes from a position above the cavity forming recess 23 of the parting surface 19, and its lower surface is located in the same plane as the upper end surface of the cavity forming recess 23. Yes.
The upper block 33 is formed with a sleeve guide hole 35 communicating with the cavity forming recess 23, and the diameter thereof is set equal to the diameter of the cavity forming recess 23.
[0018]
Reference numeral 37 denotes a gate-shaped fixed base attached to the upper surface of the fixed mold 17A, and the front end portion of the fixed base 37 faces the upper block 33 with a certain distance from the upper block 33.
Reference numeral 39 denotes a cylindrical guide shaft, and the guide shaft 39 is fixed to the fixed base 37. The lower end surface 41 of the guide shaft 39 is located in the same plane as the upper end surface of the cavity forming recess 23 with the lower half of the guide shaft 39 inserted through the sleeve guide hole 35.
[0019]
Reference numeral 43 denotes a support sleeve, and the support sleeve 43 is formed of a hard metal such as stainless steel. The support sleeve 43 has a cylindrical shape having an outer diameter equal to the diameter of the cavity forming recess 23 and an inner diameter equal to the thickness of the slide pin 31. Reference numeral 45 denotes a movable block assembled so as to form a thick flat plate, and a sleeve mounting hole 47 penetrating in the thickness direction is formed.
[0020]
The upper end portion of the support sleeve 43 is fixed to the sleeve mounting hole 47, and the guide shaft 39 is slidably inserted into the support sleeve 43. Accordingly, the movable block 45 is supported by the guide shaft 39 via the support sleeve 43 so as to be movable in the vertical direction.
In a state where the movable block 45 comes to a standby position where it abuts against the fixed base 37, the lower end of the support sleeve 43 is located in the same plane as the lower end surface of the guide shaft 39.
The movable block 45 is moved to the forward position shown in FIG. 4 when molding is performed, and this movement is performed by an air cylinder mechanism (not shown).
[0021]
On the parting surface 21 of the movable die 17B, notches 49 and 51 are formed in such a size that the upper block 33 and the lower block 27 of the fixed die 17A can be fitted to each other.
The mold apparatus 15 is configured as described above.
Therefore, when the mold is closed, the cavity forming recesses 23 are joined together to form a space that defines the outer shape of the holder 1, and a slide pin guide hole 29 is formed under this space, and a guide shaft 39 is supported above the space. The sleeves 43 are continuous.
[0022]
When a command to perform a molding operation is issued, mold closing is executed, and at the same time, the slide pin 31 is raised to the insertion position to form a cavity. This state is shown in FIG.
When the completion of mold closing is detected by a sensor (not shown), the movable block 45 is lowered to a position where it overlaps the upper block 33 as shown in FIG. As a result, the support sleeve 43 is moved to the forward movement position, and the tip portion thereof is fitted to the tip portion of the slide pin 31. Thereby, the slide pin 31 is supported by the same support structure as the double bearing structure.
[0023]
After the lowering of the movable block 45 is detected by a sensor (not shown), molten resin is injected into the cavity through the runner 25 at a predetermined timing, and the resin pushes up the front end surface of the support sleeve 43 with high pressure. Then, the support sleeve 43 is returned to the original position as shown in FIG. 5, and the holder 1 is molded in a double form. After the molding is completed, the mold is opened, and at the same time, the slide pin 31 is retracted to the standby position, and then the holder 1 is ejected from the mold.
[0024]
The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to this embodiment, and the present invention can be changed even if there is a design change without departing from the gist of the present invention. include.
For example, it is natural that the form of the molded product to which the present invention is applied is not limited to that shown in the drawings, and may be entirely cylindrical or partly cylindrical. It may be.
Further, the tubular form is not limited to a cylinder, and may be any form such as a non-circular shape, and the shapes of the guide shaft and the support sleeve may be matched to the cross-sectional shape of the tubular part.
[0025]
【The invention's effect】
As described above, the mold apparatus for resin molded product of the present invention does not require a separate part to be integrated at the time of molding, so that there is no mold or preliminary work for molding such a part. Manufacturing costs and time can be reduced.
In addition, since the tip of the slide pin is held at least by the support sleeve before injection is performed, the slide pin is stably supported by the support structure of the both bearing supports, so the high pressure of the molten resin injected into the cavity is high. There is no risk of being tilted even if it is received. Accordingly, it is possible to always ensure stable molding quality.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a principal part in an initial state of a mold apparatus for a resin molded product according to an embodiment of the present invention, with a part cut away.
FIG. 2 is a perspective view of a movable mold of the mold apparatus shown in FIG.
3 is a vertical cross-sectional view of a main part in a mold closing completion state of the mold apparatus shown in FIG. 1. FIG.
4 is an enlarged vertical cross-sectional view of a main part in a state where a support sleeve of the mold apparatus shown in FIG. 1 is in an advanced position. FIG.
5 is an enlarged vertical cross-sectional view of a main part at the completion of molding of the mold apparatus shown in FIG. 1. FIG.
6 is an enlarged perspective view of a resin molded product molded by the mold apparatus shown in FIG. 1;
FIG. 7 is a cross-sectional view showing an example of a conventional mold apparatus for a resin molded product.
FIG. 8 is an enlarged perspective view showing an example of a ring used in a conventional molding method.
9 is a cross-sectional view of a mold apparatus in the case of a method using the ring shown in FIG.
10 is a cross-sectional view at the time of completion of molding of the mold apparatus in the case of the method using the ring shown in FIG. 8. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Holder 2 End wall 3 Holder main part 3a (Main part) part 3b (Main part) part 4 Flange 5 Male screw 6 Large diameter part 7 Runner residual resin 15 Mold apparatus 17A Fixed mold 17B Movable mold 19 (fixed) Parting surface 21 of mold (movable type) 23 Part of cavity forming recess 23a (cavity forming recess) 23b (cavity forming recess) part 23c (cavity forming recess) part 25 Runner forming recess 27 (fixed mold) Lower block 29 Slide pin guide hole 31 Slide pin 32 (Slide pin) insertion portion 33 (Fixed type) upper block 35 Sleeve guide hole 37 Fixed base 39 Guide shaft 41 Lower end surface 43 (of guide shaft) Support sleeve 45 movable block 47 (movable block) sleeve mounting hole 49 (movable) notch 51 ( Dynamic type of) notch

Claims (1)

A mold apparatus for a resin molded product having a cylindrical part closed at one end, and a cavity that defines an outer surface of the cylindrical part of the resin molded product, and an inner surface of the cylindrical part that is inserted into the cavity. A slide pin, a guide shaft that is coaxial with the cavity and has a distal end surface located in the same plane as the one end surface of the cavity, and at least the distal end cross section of the cylindrical portion is slidably fitted to the guide shaft. A support sleeve having the same shape as the cross section of one end of the sleeve, and a drive for moving the support sleeve to a forward position where at least the tip of the slide sleeve is fitted to the tip of the slide pin before mold injection after the mold is closed And a support sleeve is retracted by the injection pressure when molten resin is injected into the cavity.

Images