JPH08142131A - Injection mold - Google Patents

Abstract

PURPOSE: To reduce in size a mold and to prevent the damage of the mold or an insert. CONSTITUTION: In an injection mold wherein a slide core 3 is provided at the one end of a pair of molds 2A, 2B, and a protrusion 6 protruding from the mold contact surface 3b of the core 3 toward the first cavity 4 in the molds 2A, 2B is formed, a telescopic mechanism 18 is provided for splitting the core 3 and telescopically moving the core 3 between the mold contact position and the mold separating position to reduce in size the mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die in which a slide core is detachably attached to one end of a die.

[0002]

2. Description of the Related Art Generally, there is a resin molding shown in FIG. The resin molded bodies 100A and 100B are formed by surrounding the shafts 101A and 101B with the screw 102 and the collar 1
03 is attached, and is used for a toner conveying screw of a copying machine. It should be noted that the molded body 100A of FIG. 4A, including the shaft body 101A, is molded entirely of resin, and the molded resin body 100 of FIG.
B is a resin screw 1 around a metal shaft 101B.
02 and the collar 103 are integrally molded.

The molded bodies 100A and 100B as described above are
A cavity (formed in the same mold as the molded bodies 100A and 100B) is formed on the boundary surface of a pair of butted dies, and a resin is injected into this cavity. However, the molded body 100A,
The collar 103 of 100B is provided with a step portion 103a in which a middle portion of the collar 103 projects toward the screw 102 side. Therefore, by providing the stepped portion 103a, there is a problem that the cavity has an undercut portion with respect to the mold, and the die becomes inseparable due to the undercut portion.

Therefore, there is a conventional injection molding die 50 which eliminates the above-mentioned inconvenience by providing a slide core 52 whose releasing direction is different from that of the die. This injection mold 50
Will be described with reference to FIG.

The injection molding die 50 is composed of a pair of dies 51A and 51B arranged opposite to each other and these dies 51A and 51B.
And a slide core 52 provided so as to be separable from each other. A first cavity 53 is formed between the mold 51A and the mold 51B, which is a portion of the molded bodies 100A and 100B on the screw 102 side, while the slide core 52 has a shaft of the molded bodies 100A and 100B. A second cavity 54 is formed that forms an end. further,
On the slide core 52, a convex portion 55 protruding toward the molds 51A and 51B is formed, while the molds 51A and 51B are formed.
In B, a concave portion 56 is formed so as to face the convex portion 55, and a space 57 that forms the collar 103 is formed between the convex portion 55 and the concave portion 56.

The die 50 is also provided with finger pins 58. The finger pin 58 is insertably / removably inserted into a through hole 52a obliquely provided in the slide core 52. Then, the slide core 52 is moved by the die 51A,
The slide core 52 is separated from the molds 51A and 51B, and the undercut generated by the convex portion 55 is eliminated.

In the injection molding die 50 having such a structure, the slide core 52 to the molded body 100A, 10
It is necessary to release OB. Therefore, the slide core 52 is moved rightward in the drawing to a position where it is released from the molded bodies 100A and 100B beyond the undercut elimination position by inserting and removing the finger pin 58 described above. , Molded body 100A, 1
The release of 00B was realized.

[0008]

However, the conventional injection-molding die having such a structure also has the following problems. That is, in order to release the molded bodies 100A and 100B from the slide core 52, it is necessary to move the slide core 52 by a stroke (indicated by α in the drawing) corresponding to the depth of the second cavity 54. .
Therefore, the deeper the depth of the second cavity 54 is, the longer the stroke α is.
There was a problem that the device shape of 0 became large.

Further, in the case of the resin molded body 100B,
In order to insert the shaft body 100B inside, the shaft body 101B is arranged in the open molds 51A, 51B prior to resin molding, and further, in this way, the mold bodies 51A, 51B It is necessary to externally fit the slide core 52 to the end portion of the arranged shaft body 101B. Therefore, the deeper the depth of the second cavity 54 is, the higher the probability that the shaft body 101B and the inner surface of the second cavity 54 are in contact with each other. Due to such contact, the shaft body 101B is scratched or, conversely, This causes a problem that the inner surface of the two cavities 54 is damaged, and further, the inner surfaces of the molds 51A and 51B are damaged by the shaft body 101B displaced due to the contact with the second cavity 54.

Therefore, it is an object of the present invention to reduce the size of a mold and prevent damage to the mold and inserts.

[0011]

In order to achieve such an object, according to the first aspect of the present invention, a pair of gold members which are dividable from each other and form a first cavity on the boundary surface thereof. A mold and a slide core which is provided at one end of these molds so as to be separable along a direction intersecting with the mold dividing direction and in which a second cavity communicating with the first cavity is formed. An injection-molding die having the above-mentioned feature, characterized in that the slide core is divided along a depth direction of the second cavity with a plane passing through the second cavity as a division plane.

According to the second aspect of the invention, a pair of molds which are dividable from each other and form the first cavity on the boundary surface thereof, and one end of the mold intersect with the mold dividing direction. And a slide core in which a second cavity communicating with the first cavity is provided, and the die core contact surface of the slide core has: It is an injection-molding die in which the convex part which protrudes toward the 1st cavity was formed, and the surface which passes along the inside of the 2nd cavity of the slide core along the depth direction of the 2nd cavity is made into a division plane. It is characterized in that it is provided with an advancing / retreating mechanism for advancing / retreating the slide core between the die contact position and the die separating position while dividing.

[0013]

According to the first aspect of the present invention, the slide core is divided along the depth direction of the second cavity as the dividing plane, so that the molded body is released from the slide core. Need only be performed with the slide core divided, and it is not necessary to pull out the slide core from the molded body in the depth direction of the second cavity.

Further, according to the second invention, as in the first invention, the operation of releasing the molded body from the slide core may be performed in a state where the slide core is divided. It is not necessary to pull out the cavity in the depth direction. In addition, since the convex portion projecting toward the first cavity is formed on the die contact surface of the slide core, when the slide core is divided at the time of mold release, this convex portion is different from the first cavity. There is a risk that the slide core will not be able to be divided due to undercutting, but if the slide core is split after the slide core has been retracted to the mold separation position by the advancing and retracting mechanism, the above-mentioned undercut will disappear, It can be easily split.

At this time, since the distance for retracting the slide core may be equal to the height of the convex portion, the advancing / retreating stroke of the advancing / retreating mechanism can be minimized.

In the second invention, the advancing / retreating mechanism engages with a cam groove formed in the slide core, and a cam body that engages with the cam groove to move the slide core in the depth direction of the second cavity. If the structure is provided with and, the structure of the advancing / retreating mechanism becomes simple.

Further, in the second invention, an engaging convex portion projecting toward the other split member is provided on the split surface of one of the split members constituting the slide core, and the split surface of the other split member is provided. If the engaging concave portion that engages with the engaging convex portion is provided, the following action can be obtained. That is,
When the engaging convex portion and the engaging concave portion are engaged, both split members integrally move in the advancing / retreating direction of the advancing / retreating mechanism. Therefore, the advancing / retreating operation of the slide core is performed with respect to the integrated slide core. The structure of the advancing / retreating mechanism becomes simpler.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an injection molding die according to an embodiment of the present invention. The injection molding die 1 includes a pair of dies 2A and 2B that are vertically opposed to each other, and a slide core 3 that is removably provided at the ends of the dies 2A and 2B. A first cavity 4 is formed between the mold 2A and the mold 2B, which is a portion forming the screw 102 side of the molded body 100A, 100B, while the slide core 3 has a molded body 100A, 100
A second cavity 5 forming the shaft end portion of B is provided in communication with the first cavity 4. Further, the slide core 3 is formed with a convex portion 6 protruding inside the first cavity 4, while the molds 2A and 2B are formed with a concave portion 7 facing the convex portion 6, respectively. A space 8 that forms the collar 103 is formed between the convex portion 6 and the concave portion 7.

The slide core 3 is composed of a pair of upper and lower split members 3A and 3B. The dividing surface 3a of the slide core 3 passes through the inside of the second cavity 5 along the depth direction of the second cavity 5, and the dividing surface 3a divides the second cavity 5. Further, the upper dividing member 3A has an engaging convex portion 9 that projects toward the lower dividing member 3B, while the lower dividing member 3B has an engaging concave portion 10 that engages with the engaging convex portion 9. have. The engagement protrusion 9 and the engagement recess 10 are provided at positions that do not overlap with the second cavity formation position.

Above the upper mold 2A and the upper dividing member 3A, there are a cab plate 11, a runner plate 12,
And the fixed side adapter 13 is provided in order. On the other hand, below the lower die 2B and the lower dividing member 3B, a core plate 14, an ejector plate 15, a return plate 16, and a movable adapter 17 are sequentially provided.

Further, the upper mold 2A is a cabinet plate 11
The two are integrated by being connected to the upper split member 3A.
Is a horizontal guide 11a provided on the cabinet plate 11.
Is engaged with the cavitation plate 11 so as to be horizontally movable. On the other hand, the lower split member 3B
Is engaged with a horizontal guide 14 a provided on the core plate 14 to be movably connected to the core plate 14 in the horizontal direction.

Further, the injection molding die 1 is provided with an advancing / retreating mechanism 18 for advancing / retreating the slide core 3 between the die abutting position and the die separating position. The advancing / retreating mechanism 18 includes a cam groove 19 formed in the upper split member 3A and a cam body 20.
It has and. The cam groove 19 is formed on the side surface of the upper division member 3A. Further, the cam groove 19 is formed obliquely to the lower right side in the drawing. The cam body 20 is suspended and supported by the fixed side adapter 13, and the cam groove 1 is provided at the tip thereof.
A cam protrusion 20 a that engages with the shaft 9 is provided. The cam projection 20a projects obliquely to the lower right side in the drawing so as to engage with the cam groove 19. Further, the runner plate 12 and the cavity plate 11 have through holes 11 for accommodating the cam body 20.
b and 12b are provided.

Further, between the dividing member 3A and the cavity plate 11, and between the dividing member 3B and the core plate 14.
21A and 21B are provided between and, and the split members 3A and 3B are urged by the springs 21A and 21B in the direction of separating from the molds 2A and 2B (right direction in the drawing). . On the other hand, cabinet plate 1
1 and the end of the core plate 14 has a spring 2
Stoppers 22A and 22B for receiving the split members 3A and 3B urged by 1A and 21B are provided.

The fixed adapter 13 and the runner plate 12 are moved up and down by an elevating mechanism (not shown). Further, the cabinet plate 11 is also moved up and down by a lifting mechanism (not shown) different from the lifting mechanism described above.

Next, a molding body forming process using the injection molding die 1 will be described. Here, a process of molding a molded body 100B formed by molding a metal shaft body 101B will be described. However, the shaft body-integrated molded body 1 without the shaft body 101B is described.
It goes without saying that the same molding can be performed with 00A.

First, as shown in FIG. 2, the raising / lowering mechanism raises the cabinet plate 11. Furthermore, in this state in which the fixed side adapter 13 and the runner plate 12 are further raised by another lifting mechanism, the upper mold 2A and the upper split member 3A are separated from the lower mold 2B and the lower split member 3B. Will be separated. Further, the cam projection 20 a of the cam body 20 is also separated from the cam groove 19. Furthermore, since the split members 3A and 3B are biased by the springs 21A and 21B, the slide core 3 moves from the die contact position to the stoppers 22A and 22B.
It has moved to the right in the figure to the position where it comes into contact with. Therefore, the die contact surface 3b of the slide core 3 is
The stroke 6 is separated from 2B by the stroke s, and the convex portion 6 projects from the space 8 to the outside. At this time, the stroke s
Is a very small amount because the convex portion 6 may have a stroke that only protrudes from the space 8 to the outside.

In such a state, first, the shaft body 101B
The lower die 2B and the first and second inner members in the lower dividing member 3B.
It is placed in the parts that will become cavities 3 and 4.

After mounting the shaft 101B, the cabinet plate 11 is lowered. Then, the upper mold 2A
And the upper division member 3A abuts on the lower mold 2B and the lower division member 3B, and the molds 2A and 2B, and the division member 3
A and 3B are integrated respectively. At this time, the split members 3A and 3B are integrated by the engagement of the engaging projection 9 and the engaging recess 10 so that they cannot move relative to each other in the horizontal direction in the drawing.

Further, the fixed adapter 13 and the runner plate 12 are lowered. Then, the cam body 20 also descends and the cam protrusion 20 a engages with the cam groove 19. At this time, since the engagement direction between the cam projection 20a and the cam groove 19 is the diagonally lower right direction, the upper split member 3A has the spring 2
It moves to the left side in the figure until the die contact surface 3b comes into contact with the upper die 2A, that is, stroke s, against 1A. Further, the lower split member 3B, which is integrated with the upper split member 3A so as to be relatively immovable in the left-right direction in the drawing, also includes
It moves to the left side in the figure until the die contact surface 3b comes into contact with the lower die 2B, that is, up to the stroke s, against 1B. Therefore, the injection molding die 1 is in the state shown in FIG.

At this time, the inner surfaces of the first and second cavities 4 and 5 are in sliding contact with the shaft 100B.
At this time, as shown in FIG.
Since the stroke s is only stored inside, it is extremely small. Therefore, the inner surface or the like of the first cavity 4 is forcibly brought into contact with the shaft body 101B, and the shaft body 100B,
Almost no damage occurs in the first cavity 4 or the like. Furthermore, the movement stroke s of the shaft 100B
Since it is the minimum necessary, the shaft 1 generated during the moving operation
Almost no displacement of 00B occurs, and high molding accuracy can be maintained.

In this state, the first cavity 4 and the second cavity
By injecting resin into the cavity 5, a molded body 100B
Is molded.

When the molding process is completed and the molded body 100B is sufficiently cooled, first, the fixed side adapter 13 and the runner plate 12 are raised. Then, the cam body 19 also rises, the cam projection 20a separates from the cam groove 19, and the upper split member 3A moves to the right side in the drawing until it comes into contact with the stopper 22A (stroke s) due to the elastic force of the spring 21A. . The lower division member 3B, which is integrated with the upper division member 3A so as to be relatively immovable in the left-right direction in the figure, moves to the right side in the figure until it abuts the stopper 22B (only the stroke s) by the elastic force of the spring 21B. Moving. Therefore, the injection molding die 1 is in the state shown in FIG.
That is, the convex portion 6 returns to the state of protruding from the space 8, and the convex portion 6 is no longer an undercut of the slicing core 3.

That is, the convex portion 6 projecting into the first cavity 4 becomes an undercut when the slide core 3 is released (when the slide core 3 is divided into both the split members 3A and 3B). However, as mentioned above,
Since the convex portion 6 protrudes from the space 8, such undercut does not occur.

After separating the slide core 3 from the molds 2A and 2B, the cabinet plate 11 is raised. Then
The upper mold 2A and the upper split member 3B connected to the cabinet plate 11 are also lifted and separated from the lower mold 2B and the lower split member 3B. At the time of this separating operation, the convex portion 6 is in a state of protruding from the space 8 as described above, so that when the slide core 3 is divided, the convex portion 6 is not undercut and can be smoothly divided.

After the molds 2A, 2B and the slide core 3 are released from the mold, the injection molding mold 1 to the molded body 1
Take out 00B.

In this way, the slide core 3 is attached to the molded body 10
The slide core 3 is separated from the molded body 100B by separating the slide core 3 into the dividing members 3A and 3B, instead of removing the slide core 3 from 0B. for that reason,
It is not necessary to move the slide core 3 with a large stroke along the depth direction of the second cavity 5 for releasing the slide core 3. This injection mold 1
Then, in order to release the slide core 3, it is sufficient that there is a stroke s for extracting the convex portion 6 that is an undercut from the first cavity 4, and therefore the stroke s is extremely small. Accordingly, the structures of the advancing / retreating mechanism 18 and the mold itself are made smaller.

In the above embodiment, the present invention is carried out in the injection molding die 1 having the convex portion 6 on the die contact surface 3b of the slide core 3 which is an undercut when the slide core is released. It was However, the present invention is not limited to this, and the mold contact surface 3b of the slide core 3 has a recess 30 (shown by a virtual line in FIG. 1) communicating with the first cavity 4, It goes without saying that the same effect can be obtained even when the present invention is carried out in an injection molding die in which the recess 30 becomes an undercut when the slide core is released from the mold.

[0039]

As described above, according to the first aspect of the present invention, the operation of releasing the molded body from the slide core may be performed in a state in which the slide core is divided. It is no longer necessary to pull out in the depth direction of the cavity. Therefore, it is not necessary to provide a space for pulling out the slide core in the mold,
As a result, the injection molding die could be downsized.

According to the second invention, like the first invention,
It is not necessary to pull out the slide core from the molded body in the direction of the depth of the second cavity. Therefore, it is not necessary to provide a space for pulling out the slide core in the mold, and the mold structure is correspondingly increased. It was possible to reduce the size.

Further, on the die contact surface of the slide core, the first
Since the convex portion projecting toward the cavity is formed, when the slide core is divided at the time of mold release, this convex portion becomes an undercut with respect to the first cavity, but the slide core is moved by the advancing / retreating mechanism. If the slide core is divided after retreating to the mold separating position, the above-mentioned undercut can be eliminated and the division can be performed easily. Further, at this time, since the slide core can be retracted only by the height of the convex portion, the advance / retreat stroke of the advance / retreat mechanism can be minimized, and the advance / retreat stroke does not cause an inconvenience such as enlargement of the mold structure. .

Further, since the movement stroke of the slide core can be minimized, the deviation of the insert in the mold can be reduced, and the molding accuracy can be improved accordingly.

Further, in the second invention, the advancing / retreating mechanism engages with a cam groove provided in the slide core and a cam for engaging the cam groove to move the slide core in the depth direction of the second cavity. If the structure is provided with the body, the structure of the advancing / retreating mechanism becomes simple, and the mold structure can be further miniaturized accordingly.

Furthermore, in the second invention, an engaging projection protruding toward the other split member is provided on the split surface of one of the split members constituting the slide core, and the other split member is split. The following effects can be obtained by providing an engaging recess on the surface that engages with the engaging projection. That is, when the engaging convex portion and the engaging concave portion are engaged, both the split members integrally move in the advancing / retreating direction of the advancing / retreating mechanism.
Since the forward / backward movement of the slide core by the forward / backward mechanism may be performed with respect to the integrated slide core, the structure is simplified accordingly, and the mold structure can be further downsized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of an injection molding die according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state during molding of the injection mold of the embodiment.

FIG. 3 is a cross-sectional view showing a state during molding of the injection molding die of the embodiment.

FIG. 4 is a cross-sectional view showing an example of a molded body molded by an injection molding die according to the present invention.

FIG. 5 is a cross-sectional view showing the structure of a conventional injection molding die.

[Explanation of symbols]

 2A, 2B Mold 3 Slide core 3A, 3B Dividing member 3a Dividing surface 4 1st cavity 5 2nd cavity 6 Convex part 9 Engaging convex part 10 Engaging concave part 18 Advance mechanism 19 Cam groove 20 Cam body

Claims (4)

[Claims] 1. A pair of molds that are provided so as to be separable from each other and that form a first cavity on the boundary surface thereof, and can be detached from one end of these molds along a direction intersecting the mold dividing direction. An injection molding mold provided with a slide core in which a second cavity communicating with the first cavity is formed, the slide core being provided in a depth direction of the second cavity. An injection molding die characterized in that a surface passing through the second cavity is divided as a dividing surface. 2. A pair of dies that are provided so as to be separable from each other and that form a first cavity on the boundary surface thereof, and can be detached from one end of the dies along a direction intersecting the die dividing direction. A slide core provided with a second cavity communicating with the first cavity, and a mold contact surface of the slide core protruding toward the first cavity. Is an injection molding die in which a convex portion or a concave portion communicating with the first cavity is formed, and a surface passing through the slide core in the second cavity along the depth direction of the second cavity is a dividing surface. The injection molding die is characterized by including an advancing / retreating mechanism for advancing / retreating the slide core between the die abutting position and the die separating position. 3. The advancing / retreating mechanism includes a cam groove formed in the slide core, and a cam body that engages with the cam groove to move the slide core in the depth direction of the second cavity. The injection molding die according to claim 2, wherein 4. The engaging convex portion projecting toward the other dividing member is provided on the dividing surface of one dividing member constituting the slide core, and the engaging convex portion is provided on the dividing surface of the other dividing member. The injection mold according to claim 3, further comprising an engagement recess that engages with the portion.