JP3089987B2 - Injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold used for molding a molded article such as a rubber ring.

[0002]

2. Description of the Related Art Conventionally, for example, when molding a rubber ring 10 as shown in FIG. 12, an injection mold as shown in FIG. 13 is used.

[0003] The injection molding die shown in FIG. 13 includes a fixed mounting plate 11, a runner die 12, and an upper die plate 1 in that order from the top.
3, cavity mold 14, lower mold plate 15, spacer 1
6, a movable-side mounting plate 17 and a ram 18. The ram 18 is a hydraulic cylinder for opening and closing the mold of the molding machine.

As shown in FIG. 14, a molding hole 19 for molding the outer peripheral side surface of the rubber ring 10 is formed on the cavity mold 14 side, and a rubber hole is formed on an upper surface side of the lower mold plate 15. A core mold 22 for molding the inner peripheral side surface of the ring 10 is integrally provided at a position corresponding to the molding hole 19. The molding material of the rubber ring 10 injected from the sprue flow path 20 formed in the fixed mounting plate 11 and the runner mold 12 was provided between the runner mold 12 and the upper mold plate 13. Forming hole 19 through runner channel 21 and injection hole 24 provided in upper mold plate 13
Led to.

A ram 1 provided at the lowermost part of an injection molding die
8 presses the movable side mounting plate 17, the spacer 16, and the lower mold plate 15 upward to clamp the cavity mold 14 and the upper mold plate 13 and the cavity mold 14 and the lower mold plate 15; It is carried out.

[0006]

By the way, generally,
In molding a mold, burrs are easily generated in the molded product, and it is extremely difficult to eliminate burrs.

[0007] The injection mold described above is no exception.
As shown in FIG. 4, the joining area between the components, that is,
The joining area (A) between the core mold 22 and the upper mold plate 13, the joining area (B) between the cavity mold 14 and the lower mold plate 15, and the joining area between the cavity mold 14 and the upper mold plate 13. Burr tends to occur in (C).

Therefore, conventionally, after a large burr is intentionally generated, the burr is cut off by hand, or the burr is removed by cooling only the generated burr to make it brittle to remove the burr. Burrs had been removed.

However, the method of manually removing burrs has the disadvantage that the molding material is wasted and the automation cannot be achieved because the burrs are set large considering the removal operation. However, there is a disadvantage that the number of required steps is large and cost is high.

As described above, there are various problems in removing the generated burrs. Therefore, it is desirable to eliminate burrs at the time of molding.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an injection mold capable of eliminating the occurrence of burrs on a molded product during molding by the injection mold.

[0012]

In order to solve the above-mentioned problems, an injection mold according to claim 1 forms a molded product.
A cavity mold in which a molding hole for forming
It is arranged on the bottom side of the bitty mold and pushed up by the ram.
And a lower mold plate to be clamped to the cavity mold.
The injection mold, wherein the cavity mold and the
Pressing by the ram more than the mold contact area with the lower mold plate
While setting the area large, the cavity mold or
Of the mold contact area on either side of the lower mold plate
The positioning protrusion is provided on the outer peripheral side, and the position is provided on the other side.
A positioning concave portion is provided for fitting to the predetermined convex portion.
The convex part and the positioning concave part contact each other on the upper and lower surfaces.
So that the height of the positioning protrusion is not
The depth is set to be smaller than the depth of the portion .

[0013] The molded product is a ring-shaped molded product.
In the case of an injection mold, as described in claim 2,
2. The injection molding according to claim 1, wherein the molded product is a ring-shaped molded product.
A mold having a molding hole formed in the cavity mold;
Is for molding the outer peripheral side surface of the molded article
In both cases, an upper mold plate is provided on the top side of the cavity mold.
And further disposed on the lower surface side of the cavity mold.
Core inserted into the molding hole on the upper side of the lower mold plate
A mold is attached, and the core mold is an inner periphery of the molded product.
It has an outer peripheral side for molding the side and height
Finished to the same size as the height of the cavity mold
Core mold body and a lower surface side of the core mold body.
Projected integrally at the center and smaller in diameter than the core mold body
On the upper side of the lower mold plate.
A fastening concave portion in which the fastening convex portion can be fitted is provided.
The upper and lower surfaces of the core mold body and the cavity mold
Plating layers are formed on the upper and lower surfaces, respectively,
The lower surface of the core mold body on the upper surface of the lower mold plate
In the locked state, the fastening protrusion is fitted into the fastening recess
The core mold may be attached to the lower mold plate .

[0014] According to a third aspect of the present invention, the core metal is provided.
The mold may be bolted to the lower mold plate.

[0015] Further, as set forth in claim 4, the carrier
The cavity mold is located on the top side of the cavity mold.
An upper mold plate having an injection hole communicating with the shape hole, and the upper mold
Disposed on the upper side of the plate, the lower surface of the plate and the upper die plate
A runner channel communicating with the injection hole is formed between
In the case of an injection mold with a runner mold,
In the runner channel, the upper mold plate upper surface or
The height dimension of the runner is
A locking projection with the same dimensions as the gap in the height direction of the
You may.

[0016]

[0017]

In the injection mold according to claim 1, the contact area between the cavity mold and the lower mold plate is set.
Because the pressing area of the ram is set larger than the area,
The ram covers the entire mold contact area between the cavity mold and the lower mold plate.
Press evenly across the surface, so that the lower mold plate
Eliminates the resulting gap between the lower mold plate and the cavity mold
be able to. Also provided on the outer periphery of the mold contact area
Positioning protrusion and positioning recess
Adjust the height of the positioning protrusion so that it does not touch
Is set smaller than the depth of
Cavity caused by contact with positioning recess
The gap between the mold and the lower mold plate can be eliminated. Ma
In addition, in the injection mold according to the second aspect, in addition to the above operation,
Te, the central portion of the lower surface of the core mold body height is finished the same as the height of the cavity mold together with an outer peripheral side surface and the core mold body for forming the inner peripheral side surface of the molded article A core mold having a fastening protrusion that is integrally protruded and smaller in diameter than the core mold body, and a lower mold plate having a fastening recess in which the fastening protrusion can be fitted. Formed by separate members, plating layers are formed on at least the upper and lower surfaces of the core mold body and the upper and lower surfaces of the cavity mold, and the lower surface of the core mold body is locked to the upper surface of the lower mold via those plating layers. In this state, the fastening protrusion is fitted into the fastening recess, and the core mold is attached to the lower mold plate. It is equal to the increase in height due to the plating process, and consequently their height The gap between the core die and the upper die plate due to the difference can be eliminated.

Further, as claimed in claim 3, wherein, when bolting the core mold to the lower mold plate, in addition to the action described above, the adhesion with a strong force to the core metal mold and the lower mold plate Thus, the gap generated between the core mold and the lower mold plate can be effectively eliminated.

[0019]

[0020]

According to a fourth aspect of the present invention, in the runner flow path, the height dimension is set at a predetermined location on one of the upper die plate upper surface and the runner die lower surface in the height direction of the runner flow path. If a locking projection having the same size as the interval is provided and the locking projection is locked to the upper surface of the upper mold plate or the lower surface of the runner mold on the other side, the locking projection is used. The mold clamping force can be applied to the entire surface of the mold plate on average, preventing distortion due to the lifting of the upper mold plate and preventing a gap generated between the upper mold plate and the cavity mold. .

[0022]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a rubber ring 10 shown in FIG.
FIG. 1 is a cross-sectional view schematically showing an entire injection molding die of the present embodiment used for molding of the present invention.

That is, this injection molding die is provided with, from the top, a fixing side mounting plate 30, a runner die 31, an upper die plate 32, and a molding hole 34 for molding the outer peripheral side surface of the rubber ring 10. A cavity mold 33, a core mold 35 that can be inserted into the molding hole 34, and molds the inner peripheral side surface of the rubber ring 10, and a lower mold plate in which the core mold 35 is provided in a projecting manner on the upper surface side. 36, spacer 37, movable side mounting plate 38, ram 3
9.

The molding material of the rubber ring 10 injected from the sprue flow passage 40 formed in the fixed side mounting plate 30 and the runner mold 31 is formed between the runner mold 31 and the upper mold plate 32. It is guided from the runner channel 59 into the molding hole 34 via the injection hole 60 formed in the upper mold plate 32.

The ram 39 presses the movable-side mounting plate 38, the spacer 37, and the lower mold plate 36 upward, so that the cavity mold 33 and the lower mold plate 36, and the cavity mold 33 and the upper mold plate 3
Perform mold clamping with 2.

Hereinafter, details of this embodiment will be described in comparison with a conventional example. The conventional injection mold and the rubber ring 10 of the molded product will be described with reference to FIGS.

[1. Deburring in the joint area between the core mold 35 and the upper mold plate 32] Conventionally, the core mold 22 is formed integrally with the lower mold plate 15, as shown in FIG.
Therefore, when the surfaces of the cavity mold 14, the core mold 22 and the lower mold plate 15 are respectively polished to form the plating layers 25 and 26 by hard plating, the height of the entire cavity mold 14 becomes lower. A plating layer 26 on the upper surface of the mold plate 15 and a plating layer 25 on the upper and lower surfaces of the cavity mold 14;
25 increases the thickness h of the plating layer by three times, whereas the height dimension of the core mold 22 only increases the thickness h of the plating layer because the plating layer 26 is only formed on the upper surface thereof. As a result, at the time of mold clamping, a gap 27 having a size twice as large as the thickness h of the plating layer is formed between the core mold 22 and the upper mold plate 13 as shown in FIG. The molding material intrudes into 27 and burrs are generated. In FIGS. 2 and 6, the thickness h of the plating layer is drawn larger than the actual thickness for easy understanding.

Therefore, in the present embodiment, as shown in FIG. 2, the core mold 35 is formed of a member different from the lower mold 36. That is, the core mold 35 has an outer peripheral side surface 46a for molding the inner peripheral side surface of the rubber ring 10, and has a height dimension finished to the same dimension as the height dimension of the cavity mold 33. The lower mold plate 36 includes a fastening projection 48 integrally projecting from a lower surface side central portion of the core mold body 46 and having a diameter smaller than that of the core mold body 46.
On the upper surface side of the fastening recess 4 into which the fastening projection 48 can be fitted.
9 are provided. Then, plating was performed on the upper surface, the outer peripheral side surface 46a, and the lower surface of the core mold body 46, the upper and lower surfaces of the cavity mold 33, and the upper surface of the lower mold plate 36 to form plated layers 50, 51, and 52, respectively. Thereafter, the fastening projection 48 is fitted into the fastening recess 49 while the lower surface of the core mold body 46 is locked on the upper surface of the lower mold plate 36 via the plating layers 50 and 52, and the core mold is bolted 44. 35 was fixed to the lower mold plate 36. The core mold spacer 43 is inserted into the bottom of the fastening recess 49.

Thus, the change in height due to the plating of the core mold 35 is caused by the plating layers 50 and 50 on the upper and lower surfaces of the core mold body 46 and the plating layers 52 of the lower mold plate 36.
The height of the cavity mold 33 due to the plating process is also changed by the plating layers 51 and 51 on the upper and lower surfaces of the cavity mold 33 and the lower mold plate 36.
The height is increased by 3h due to the plating layer 52 on the upper surface of the core mold 35, and the height changes are the same in both cases. Therefore, no gap is formed between the upper surface of the core mold 35 and the lower surface of the upper mold plate 32 during mold clamping.

Therefore, burrs generated between the upper surface of the core mold 35 and the lower surface of the upper mold plate 32 when the rubber ring 10 is formed can be eliminated. Further, the core mold 35 and the lower mold plate 36 are fastened to each other with a strong force by fastening the core mold 35 to the lower mold plate 36 with bolts 44.
Can be eliminated, and burrs generated here can also be eliminated.

[2. Cavity mold 33 and lower mold plate 36
Conventionally, as shown in FIG. 7, the cavity mold 14, the lower mold plate 15, and the upper mold plate 13 are clamped by pressing the injection mold upward from below. The pressing area m of the ram 18 is smaller than the mold contact area n between the lower surface of the cavity mold 14 and the lower mold plate 15. Therefore, when the ram 18 is pressed upward, distortion occurs in a region not pressed by the ram 18, and the lower mold plate 15 and the cavity mold 14 are not completely adhered to each other, and a gap may be generated between them. There is.

Therefore, in this embodiment, as shown in FIG. 1, the pressing area S of the ram 39 is set to be larger than the mold contact area s between the cavity mold 33 and the lower mold plate 36. .

As a result, the pressing force of the ram 39 acts uniformly in the entire area of the mold contact area s, and the lower mold plate 36 is not distorted as in the prior art. The space between the cavity mold 33 and the mold contact region s is more completely adhered.

Conventionally, as shown in FIG. 8, the mold contact area s on the lower surface side of the cavity mold 14 is adjusted so that the cavity mold 14 and the lower mold plate 15 are clamped at an appropriate position. In the peripheral portion, a ring-shaped positioning projection 51 is provided.
Are provided so as to project downward, while the lower mold plate 15
A ring-shaped positioning concave portion 52 into which the positioning convex portion 51 can be fitted is provided on a peripheral edge portion of the mold contact area s on the upper surface of the mold.
Is provided.

On the upper surface of the positioning recess 52, there is provided a ring groove 53 into which an annular ring (not shown) for keeping the airtightness between the cavity mold 14 and the lower mold plate 15 during mold clamping is fitted. ing.

In this case, the projection height H of the positioning projection 51 is formed to have the same size as the depth M of the positioning recess 52.

Therefore, if any processing error or assembling error occurs, the cavity mold 14 is moved to the lower mold plate 1.
5, the lower surface of the positioning protrusion 51 abuts against the upper surface of the positioning recess 52, and the cavity mold 14 and the lower mold plate 15 do not completely adhere to each other in the mold contact region s. There may be a gap in

Therefore, in the present embodiment, as shown in FIG.
Is set to be smaller than the depth M, so that the positioning convex portion 51 and the positioning concave portion 52 do not come into contact with each other during mold clamping.

As a result, even if a slight processing error or the like occurs during the processing of the mold, the positioning convex portion 51 and the positioning concave portion 52 do not come into contact with each other, and the cavity mold 33 and the lower mold plate 36 do not come into contact with each other. Are completely adhered in the mold contact area s.

As described above, the positioning projections 51 and the positioning recesses 52 are prevented from coming into contact with each other.
Is set to be larger than the mold contact area s between the cavity mold 33 and the lower mold plate 36, so that the cavity mold 33 and the lower mold plate 36 are more completely in the mold contact area s. Adhesion is made, and burrs are not generated in these joining regions.

In this embodiment, the case where the positioning convex portion 51 is provided on the cavity mold 33 side and the positioning concave portion 52 is provided on the lower mold plate 36 side is described. Even when the positioning concave portion is provided on the plate 36 side and on the cavity mold 33 side, the same effect can be obtained by setting the height of the positioning convex portion to be smaller than the depth of the positioning concave portion.

[3. Cavity mold 33 and upper mold plate 32
Removal of Burrs in the Junction Region with the Conventional], FIGS. 9 to 1
As shown in FIG. 1, the runner flow path 21 formed between the upper mold plate 13 and the runner die 12 is formed by providing a certain gap between them, and the runner flow path 21 On the side of the upper mold plate 13, two injection holes 24 for pouring a molding material into a plurality of molding holes 19 are formed for each molding hole 19. In the plan view of the upper mold plate 13 shown in FIG. 10, a large number of injection holes 24 are dispersedly formed over the entire surface of the upper mold plate 13 so that a large number of rubber rings 10 can be formed at one time. I have.

However, in such a conventional mold configuration, when the mold is clamped, the upper mold plate 13 and the runner mold 12 come into contact with each other only at the outer periphery surrounding the runner flow path 21 and are clamped in the vertical direction. Even if you apply force,
In the region where the runner flow path 21 is provided, a sufficient clamping force is not applied, and the clamping force cannot be applied uniformly to the entire region of the upper mold plate 13. Therefore, the pressure of the molding material injected from the sprue flow path 20 tends to cause the upper portion of the upper mold plate 13 to be distorted upward, and a gap is formed between the cavity mold 14 and the upper mold plate 13. May occur.

Therefore, in the present embodiment, as shown in FIGS. 4 and 5, on the lower surface of the runner mold 31, between each pair of injection holes 60 communicating with the molding holes 34.
Locking protrusions 62 having the same height dimension as the runner channel 59 are formed, and the lower surface of the locking protrusions 62 is locked to the upper surface of the upper mold plate 32 during mold clamping. I try to make it.

Therefore, at the time of mold clamping, the mold clamping force acting on the upper mold plate 32 from the runner mold 31 is not limited to the peripheral edge portion 32a but also to the region where the runner flow path 59 is provided. The upper mold plate 32 is transmitted through the convex portion 62 and is distorted so that the upper mold plate 32 is lifted upward in the region where the runner flow path 59 is provided.
There is no gap between the mold 2 and the cavity mold 33, and burrs generated there can be eliminated.

The position at which the locking projection 62 is provided is not limited to between the pair of injection holes 60 described above.
Any position may be used as long as the runner channel 59 is provided on the lower surface of the first mold plate or the upper surface of the upper mold plate 32.

[0047]

As described above, according to the injection molding die of the first aspect of the present invention, the cavity die, the lower die plate and
Set the ram pressing area larger than the mold contact area of
Prevents distortion of the lower mold plate in the mold contact area
Can occur between the lower mold plate and the cavity mold
Burr can be prevented. Also, the outer periphery of the mold contact area
The height of the positioning projections provided on the
Since it is set to be smaller than the depth,
Since the convex part and the positioning concave part do not contact each other,
Clearance between the cavity mold and the lower mold plate in the contact area
Can be eliminated, preventing burrs generated between them
can do. In addition, as described in claim 2,
For example , plating can be performed on the lower surface of the core mold body and the upper surface of the lower mold plate, and the height of the core mold body is equal to the height of the cavity mold, and the core mold and the upper mold can be plated. It is possible to eliminate the gap generated between the plates and to prevent burrs generated between them. Further, it is possible to omit steps such as a conventional deburring process, and it is possible to automate a molding process and reduce costs.

[0048] Moreover, as claimed in claim 3, wherein, when the core mold so that the bolt fastened to the lower die plate, in close contact with a stronger force than the core metal mold and the lower mold plate, core Burrs generated between the mold and the lower mold plate can be effectively prevented.

[0049]

[0050]

According to a fourth aspect of the present invention, the height dimension at the predetermined position on the lower surface of the runner mold or the upper surface of the upper mold plate in the runner flow path is the same as the height direction interval of the runner flow path. By providing the stopper convex portion, the mold clamping force can be transmitted to the upper mold plate from the runner mold via the locking convex portion even in the region where the runner channel is provided, and the runner channel is In the provided area, distortion due to the upward lifting of the upper mold plate can be prevented, and burrs generated between the upper mold plate and the core mold and between the upper mold plate and the cavity mold can be prevented. be able to.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing a core mold of the injection mold according to the first embodiment.

FIG. 3 is a cross-sectional view showing a joining state of a cavity mold and a lower mold plate of the injection mold according to the first embodiment.

FIG. 4 is a plan view showing an upper mold plate of the injection molding die of the same.

FIG. 5 is a cross-sectional view showing a relationship between a runner flow path and a projection of the above-described injection molding die.

FIG. 6 is a sectional view showing a conventional core mold.

FIG. 7 is a cross-sectional view showing a state of joining a conventional cavity mold and a lower mold plate.

FIG. 8 is a cross-sectional view showing a problem of a conventional injection mold.

FIG. 9 is a cross-sectional view showing a conventional runner channel provided between a runner mold and an upper mold plate.

FIG. 10 is a plan view showing a conventional upper mold plate.

FIG. 11 is a sectional view showing a conventional runner channel.

FIG. 12 is a view showing a rubber ring.

FIG. 13 is a cross-sectional view schematically showing an entire conventional injection molding die.

FIG. 14 is a cross-sectional view showing locations where burrs occur.

DESCRIPTION OF SYMBOLS 10 Rubber ring 31 Runner mold 32 Upper mold plate 33 Cavity mold 34 Molding hole 35 Core mold 36 Lower mold plate 39 Ram 51 Positioning convex portion 52 Positioning concave portion 59 Runner channel 62 Locking Convex part

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-53-58924 (JP, A) JP-A 4-17920 (JP, U) JP-A 55-4870 (JP, U) JP-A 53-589 81674 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/26-45/44 B29C 33/00-33/76

Claims (4)

(57) [Claims] A molding hole for molding a molded article is formed.
Cavity mold and the bottom side of the cavity mold
Is disposed and pushed up by the ram to
Injection mold with a lower mold plate to be clamped to the mold.
Therefore, the mold contact area between the cavity mold and the lower mold plate is
Also, if the pressing area by the ram is set to be large,
One of the cavity mold or the lower mold plate
A positioning projection is provided on the outer peripheral side of the mold contact area on the side
On the other hand, on the other side, a positioning recess fitted to the positioning projection is provided.
Part, and the positioning convex part and the positioning concave part are
The positioning projections should be
Height was set smaller than the depth of the positioning recess
An injection molding die characterized by the following. 2. The molded product is a ring-shaped molded product.
Item 2. The injection molding die according to Item 1, wherein a molding hole formed in the cavity die has a shape of the molded product.
For forming the outer peripheral side surface,
An upper mold plate is arranged on the upper side of the cavity mold,
Upper surface of lower mold plate arranged on the lower surface side of the cavity mold
A core mold inserted and arranged in the molding hole is attached to the side
The core mold is for molding an inner peripheral side surface of the molded product.
The cavity has an outer peripheral side surface and the height dimension is
Core mold body finished to the same dimensions as the mold height
And a centrally protruding portion at the lower surface side central portion of the core mold body.
And a fastening projection having a diameter smaller than that of the core mold body.
On the other hand, the fastening projection can be fitted on the upper surface side of the lower mold plate.
At least the core mold body
The upper and lower surfaces of the cavity mold and the upper and lower surfaces of the cavity mold, respectively.
Forming a core layer, and through the plating layers, the core metal
With the lower surface of the mold body locked to the upper surface of the lower mold plate,
Fit the connecting convex part to the fastening concave part and lower the core mold to the lower part.
An injection molding die, which is attached to a die plate. 3. The core mold is bolted to the lower mold plate.
3. The injection molding according to claim 2, wherein the injection molding is performed.
Mold. 4. A method according to claim 1, further comprising the step of :
Has an injection hole communicating with the molding hole of the cavity mold
An upper mold plate, disposed on an upper surface side of the upper mold plate,
Between the lower surface of the upper mold plate and the upper surface of the upper mold plate.
And a runner mold forming a runner flow path
Item 2. The injection mold according to Item 1 , wherein the upper mold plate upper surface or
The height dimension is set at a predetermined location on the lower surface of the runner mold.
A locking projection with the same dimensions as the height
Injection molding dies characterized by being eccentric.