JPH0623757A - Molding mold provided with slide core - Google Patents

Abstract

PURPOSE:To provide a molding mold provided with a slide core which prevents a slide cam driving and holding the slide core from becoming fatigue failure and can hold dimensional accuracy of a molded product. CONSTITUTION:The title mold is provided with a cave part 14 provided in a template 5 or 6, a slide core 11 inserted into a support surface of a core of the cave part 14 and a matter which is the first slide cam 20 provided by placing a template of the cave part 14 on its back, a cam face 201 of its front is fitted over a rear end of the slide core 11, the slide core 11 is moved forward and held. Furthermore, a matter which is the second slide cam 21 provided integrally with the first slide cam 20, a cam face 211 of its rear is fitted in a hole or a groove part 111 provided in a belly part of the slide core 11 and moved backward is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die with a slide core, and more specifically, a slide core forming an undercut portion (partial shape of a molding that cannot be ejected) of the molding is closed. The present invention relates to a mold die with a slide core that moves forward and backward in a state.

[0002]

2. Description of the Related Art FIG. 5 is a view showing the structure of a conventional mold having a slide core. In FIG.
₁ is the ejector plate (bottom), 2 ₂ is the ejector plate (top),
3 is a spacer block, 4 is an ejector pin, 5 is a movable side mold plate (used as a core support plate in this example), 6 is a fixed side mold plate (cavity support plate), and 7 is a movable side mold plate 5 and a fixed side mold. A parting line separating the plate 6, 8 is a fixed side mounting plate, 9 is a sprue bush, 10 is a molded product (product),
10 ₁ is a hole portion of the molded product, 10 ₂ is a rib portion of the molded product, 11
Is a slide core, 11 ₁ is a hole or groove penetrating the abdomen of the slide core, 12 is a slide cam, 12 ₁ is a core pushing surface of the slide cam 12, 12 ₂ is the same core drawing surface, 13 is a hydraulic cylinder, and 14 is A cavity portion 14 ₁ for accommodating the slide core mechanism portion provided in the movable side mold plate 5 is a core supporting surface of the cavity portion 14.

When the molded product 10 as shown in the figure is molded, the holes 10 ₁ and the ribs 10 ₂ of the molded product 10 are so-called undercuts. Conventionally, injection molding is performed by the following method to deal with undercut. First, the mold plates 5 and 6 are closed, then the hydraulic cylinder 13 is moved forward, and the slide cam 12 directly connected thereto is pushed down. As a result, the pushing surface 12 ₁ of the slide cam 12 comes into pressure contact with the front surface of the core groove 11 ₁ and pushes the slide core 11 forward. Next, the molten resin is injected from the sprue bush 9, and after holding and measuring the pressure, the mold plates 5 and 6 are cooled to solidify the molded product 10. Next, the hydraulic cylinder 13 is retracted and the slide cam 12 is pulled up. As a result, this time, the pull-out surface 12 ₂ of the slide cam 12 comes into pressure contact with the rear surface of the core groove 11 ₁ , and the slide core 1
Pull 1 toward you. Thereafter, the mold plates 5 and 6 are opened and the ejector pin 4 is advanced to eject the molded product 10.

FIG. 6 is a diagram for explaining the problems of the prior art. The pressure P at the time of injection and holding of the molten resin is usually 200 to 3
It is 00 Kg / cm ² . This pressure P is applied to the area S of the front surface of the slide core 11 at the time of injecting and holding the molten resin, and as a result, the slide cam 12 receives a load F of approximately (P × S) from the slide core 11. Molded product 1
Before the ejection of 0, the slide core 11 must be retracted by overcoming the frictional force between the slide core 11, the core supporting surface 14 ₁ and the rib portion 10 ₂ .

[0005] Conventionally, the front and rear surfaces 12 ₁ as illustrated forward-retention and retraction of such slide cores 11, 12
Only the slide cam 12 having a single shape having the cam surface ₂ is used. As a result, stress is intensively applied to the inclination start portion 12 ₃ of the slide cam 12,
When injection molding was repeatedly performed in such a state, a crack C eventually occurred in the tilt start portion 12 _3, and fatigue fracture was often caused.

Even before such fatigue fracture occurs, the slide cam 12 bends as shown by the dotted line in the figure due to the strong load F, and as a result, the slide core 11 retracts from the normal position value, which results in a molded product. 10 plate thickness D
There has been a problem that the height H of the ribs becomes defective on the + side.

[0007]

As described above, in the conventional mold with a slide core, the slide core can be advanced, held and retracted only by a single-shaped slide cam having front and rear surfaces as cam surfaces. Because of this structure, the slide cam was bent, and a defective product was molded, and the slide cam often suffered fatigue failure.

An object of the present invention is to provide a molding die with a slide core which can prevent the fatigue breakage of the slide cam that drives and holds the slide core and can maintain the dimensional accuracy of the molded product.

[0009]

The above-mentioned problems can be solved by the structure shown in FIG. That is, the mold with slide core of the present invention is provided with the cavity 14 provided in the template 5 or 6 and the slide core 11 inserted into the core supporting surface 14 ₁ of the cavity 14.
When, a first slide cam 20 provided by the template cavities 14 on the back, the cam surfaces 20 ₁ of the front advances the trailing portion engages the slide core 11 of the slide core 11 And a second slide cam 21 that is integrally provided with the first slide cam 20 and that is retained, and the rear cam surface 21 ₁ is a hole or groove portion 11 ₁ provided in the abdomen of the slide core 11. Engaging with and moving the slide core 11 backward.

[0010]

In the mold with slide core of the present invention, the hydraulic cylinder 13 is moved forward with the mold plates 5 and 6 closed, and the first and second slide cams 20 and 21 directly connected thereto are connected. Push down. Thus the cam surface 20 ₁ of the front face of the first slide cam 20 pushes before the slide core 11 by the rear end portion engaged with the cam action of the slide core 11. Next, the molten resin is injected from a sprue bush (not shown), held under pressure, and weighed. At that time, the first slide cam 20 receives a strong load F from the slide core 11, but since the first slide cam 20 has a part of the sturdy template 5 on its back, The load F can be locked with sufficient mechanical strength. Further, the mold plates 5 and 6 are cooled to solidify the molded product 10, and then the hydraulic cylinder 13
Is retracted to pull up the first and second slide cams 20 and 21. Along with this, this time the second slide cam 2
Cam surfaces 21 ₁ of the rear surface of the 1 retracts the slide core 11 by the cam action engages the hole or the groove portion 11 ₁ formed in the abdomen of the slide core 11. At this time, the force applied to the second slide cam 21 is small. After that, template 5, 6
Is opened and an ejector pin (not shown) is advanced to eject the molded product 10.

Thus, the first and second slide cams 2
It is possible to prevent 0,21 fatigue fracture and maintain the dimensional accuracy of the molded product 10. Preferably, the slide cam support pin 15 for reinforcing and supporting and guiding the back surface of the first slide cam 20 is provided, which is supported by the mechanical portion of the mold clamping portion or the plasticizing injection portion.

Further, preferably, a spring or spring mechanism portion 16 for constantly applying a backward force to the slide core 11 is provided.

[0013]

Embodiments of the present invention will now be described with reference to the accompanying drawings.
Will be described in detail. The same reference numerals are used throughout the drawings.
Or, it indicates the corresponding part. FIG. 2 shows the screen of the first embodiment.
It is a diagram showing the structure of the mold with a ride core.
1 is the movable side mounting plate, 2₁Is the ejector plate (bottom), 2₂
Is an ejector plate (top), 3 is a spacer block, 4 is an
The ejector pins 5 are movable mold plates (in this example, core support plates).
, 6 is a fixed-side mold plate (cavity support plate),
7 is a party for separating the movable side template 5 and the fixed side template 6.
Gline, 8 fixed plate, 9 sprue bush,
10 is a molded product (product), 10₁Is the hole of the molded product,₂
Is a rib part of the molded product, 11 is a slide core, 11₁Is
A hole or groove that penetrates the abdomen of the id core 11, 20 is the first
1 slide cam, 20₁Is the front cam surface, 21 is
Second slide cam, 21₁Is the rear cam surface, 20
₂Integrally supports the first and second slide cams 20 and 21.
Support member to hold, 13 is a hydraulic cylinder, 14 is a slide
A cavity for accommodating the core mechanism, 14₁Is installed in the cavity 14.
Girder core support surface, 14 ₂Is the cam support surface.

For example, a part of the movable side mold plate 5 is hollowed out and emptied.
The sinus 14 is formed. The core supporting surface 14 of the hollow portion 14
₁Fit the head of the slide core 11 into the
14 ₁Support for learning. Furthermore, the cavity 14
Cam support surface 14₂The first and second as the supporting and guiding surfaces
Insert the integrated slide cams 20 and 21
However, the first slide cam 20 has its cam surface 20₁Sura
The second core so as to engage with the rear end of the id core 11.
The ride cam 21 is a hole or groove 11 in the slide core 11.₁
Insert so that they fit together. And the first and second
Of the hydraulic cylinder 13 on the heads of the slide cams 20 and 21 of
Directly connect the action axis.

With such a construction, first, the mold plates 5 and 6 are closed, then the hydraulic cylinder 13 is moved forward, and the first and second slide cams 20 and 21 directly connected thereto are pushed down. Thereby, the cam surface 20 _{1 on} the front surface of the first slide cam 20
Engages with the rear end of the slide core 11 and pushes the slide core 11 forward by the cam action. The second slide cam 21 and the hole or groove 11 of the slide core 11 at that time
_{Since a} slight play is provided between the second slide cam 21 and _{1 as} shown, no load is applied to the second slide cam 21. Next, inject the molten resin from the sprue bush 9,
Hold and weigh. In that case, the first slide cam 2
0 is will receive a strong load F from the slide core 11, since the first slide cam 20 is a portion of the heavy-duty type plate 5 and the cam supporting surface 14 _2, sufficient mechanical this load F It is strong and can be locked. Therefore, the slide core 11 is also held in a fixed position.

Further, the mold plates 5 and 6 are cooled to solidify the molded product 10. Next, the hydraulic cylinder 13 is retracted, and the first and second slide cams 20 and 21 are pulled up. Along with this, this time, the front cam surface 20 _{1 of} the first slide cam 20 separates from the rear end of the slide core 11, and the rear cam surface 21 _{1 of} the second slide cam 21 continues to slide. The slide core 11 is retracted by engaging with a hole or groove 11 ₁ provided in the abdomen of 11 and by the cam action thereof. At that time, the force applied to the second slide cam 21 is
Slide core 11, core support surface 14 ₁ and rib portion 10 ₂
The frictional force between and is relatively small. After that,
Open the mold plates 5 and 6 and move the ejector pin 4 forward,
The molded product 10 is ejected.

Thus, the first and second slide cams 2
It is possible to prevent 0,21 fatigue fracture and maintain the dimensional accuracy of the molded product 10. FIG. 3 is a view showing the structure of the mold for a slide core according to the second embodiment, in which 15 is a slide cam support pin and 15 ₁ is its cam support surface. In this example, the cam support surface 14 of the template 5 is shown as shown.
_{Since the} thickness of the portion ₂ is thin, the first slide cam 20 cannot be supported with sufficient mechanical strength. Therefore, a slide cam support pin 15 that is supported by the mechanism portion of the mold clamping portion (not shown) or the movable side mounting plate 1 is provided, and its head is penetrated to the middle of the mold plate 5 as shown in the drawing, and the front surface thereof is provided. And a cam support surface 15 ₁ flush with the cam support surface 14 ₂ so that the back surface of the first slide cam 20 is substantially supported and guided.

[0018] Figure 4 is a diagram showing a configuration of a slide mold with cores of the third embodiment, 11 ₂ flange portion in FIG, 16 is a spring mechanism. In this example, the flange portion 11 provided on the abdomen of the slide core 11 as illustrated.
_A spring mechanism portion 16 is provided between the core support surface 14 ₁ and the core support surface 14 ₁ around the ₂ to constantly apply a backward force to the slide cam 11. Even in this case, since the rear end surface of the first slide cam 20 is supported with sufficient mechanical strength, there is no influence on the dimensional accuracy of the molded product 10. On the other hand, when the slide core 11 is retracted by the second slide cam 21, the force of the spring mechanism portion 16 acts to assist the pulling-out action of the slide core 11 by the second slide cam 21. Two
The burden of 1 is significantly reduced. The spring mechanism 16 may be composed of a leaf spring or the like.

In the above embodiment, the slide core 11 and the slide cam mechanisms 20, 21 and the like associated therewith are provided on the movable mold plate 5 side, but the invention is not limited to this. These may be provided on the fixed-side template 6 side. Also,
In the above embodiment, the slide core 11 suitable for the shape of the molded product 10 as an example and the slide cam mechanism portion 2 associated therewith.
Although the structure and the form of 0 and 21 are shown, it is not limited to this. In addition, it is apparent that the molding dies with slide cores having various structures and forms can be configured according to molded products having different shapes without departing from the concept of the present invention.

[0020]

As described above, according to the present invention, the template 5
Or, the hollow portion 14 provided in 6, the slide core 11 inserted into the core supporting surface 14 ₁ of the hollow portion 14, and the first slide cam 20 provided with the template of the hollow portion 14 as a back,
The front cam surface 20 ₁ engages with the rear end portion of the slide core 11 to move the slide core 11 forward and hold it, and the second one provided integrally with the first slide cam 20.
Of the slide cam 21 of the rear surface of the cam surface 21 ₁
Includes a member that engages with a hole or groove 11 ₁ provided in the abdominal portion of the slide core 11 to retract the slide core 11, so that fatigue damage of these slide cams can be prevented and the dimensional accuracy of the molded product is always maintained. Can be maintained.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a diagram showing a configuration of a mold die with a slide core according to the first embodiment.

FIG. 3 is a diagram showing a configuration of a mold die with a slide core according to a second embodiment.

FIG. 4 is a diagram showing a configuration of a mold die with a slide core according to a third embodiment.

FIG. 5 is a diagram showing a configuration of a conventional mold die with a slide core.

FIG. 6 is a diagram for explaining the problems of the conventional technique.

[Explanation of symbols]

5, 6 Template 10 Molded product 11 Slide core 11 ₁ Hole or groove 20, 21 First and second slide cams 20 ₁ , 21 ₁ Cam surface 13 Hydraulic cylinder 14 Cavity 14 ₁ Core support surface

Claims (3)

[Claims] 1. A cavity (1) provided in a template (5 or 6).
4), the slide core (11) inserted into the core supporting surface (14 ₁ ) of the cavity (14), and the first slide cam (20) provided with the template of the cavity (14) as the back. A cam surface (20 ₁ ) on the front side thereof engages with a rear end portion of the slide core (11) to advance and hold the slide core (11), and a first slide cam (20) A second slide cam (21) integrally provided on the rear side of the cam surface (2).
1 ₁₎ is a hole or a groove portion formed in the abdomen (11 ₁₎ and engages the slide core (11) sliding mold with cores, characterized in that it comprises, as retracting the slide core (11) . 2. A slide cam support pin (15) for reinforcing and supporting and guiding the back surface of the first slide cam (20), the slide cam support pin (15) being supported by a mechanical part of a mold clamping part or a plasticizing injection part. The mold die with a slide core according to claim 1, wherein 3. The mold with a slide core according to claim 1, further comprising a spring or a spring mechanism section (16) for constantly applying a backward force to the slide core (11).