Injection mold

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention is hot using a gate valve relates injection molds Toran'na format, suitable for use such as injection molding of a resin containing a particular magnetic powder is likely to accelerate the wear of the nozzle tip and fibrous crystals It is a thing.

【0002】

[Conventional technology]

In a hot runner type injection molding die using a gate valve, there are places where the cross-sectional area of the resin passage is extremely small, such as near the gate, so the hardness is higher than that of a resin with poor fluidity, for example, a general resin alone. In a plastic bond magnet material containing magnetic powder, the filling peak pressure during injection molding increases, and the nozzle tip formed with the gate tends to wear very quickly. For this reason, when the plastic bond magnet material is injection-molded with a hot runner type injection-molding mold using a gate valve, the nozzle tip on which the gate is formed, the gate pin for opening and closing the gate, the fixed-side mold, and the movable side It has been pointed out that the gate portion formed between the mold and communicating with the molding cavity is severely worn, and the molded product is liable to have an appearance defect such as burrs, resulting in poor mass productivity.

【0003】

As conventional techniques, Japanese Patent Publication No. 5-33887, Japanese Patent Publication No. 7-67715, and Japanese Patent Publication No. 7-10548 describe the tip of a heating cylinder in a hot runner type resin injection molding die using a gate valve. It is disclosed that the gate of the nozzle mounted on the gate is composed of a replaceable nozzle block attached to the gate valve device, and the gate portion can be replaced when the gate portion is damaged.

【0004】

[Problems to be Solved by the Invention]

In the case of the conventional injection molding dies disclosed in Japanese Patent Publication No. 5-33887, Japanese Patent Publication No. 7-67715, and Japanese Patent Publication No. 7-10548, injection is performed from an injection molding machine in order to replace the nozzle block. After removing the molding die, disassembling it and taking out the gate valve device, the nozzle block must be replaced, which is extremely poor in workability. In particular, when the nozzle block is heavily worn like the above-mentioned plastic bond magnet material, the nozzle block needs to be replaced frequently, so that the workability is significantly impaired in such a structure, and the operating rate of the device is lowered. Some improvement is needed so as not to invite.

【0005】

Further, the plastic bond magnet material has poor fluidity as compared with a general synthetic resin material alone, and it is necessary to raise the resin temperature to a temperature higher than these, for example, about 250 ° C. Moreover, when the plastic bond magnet material is injection-molded, the heat generated in the vicinity of the gate is transferred to the molding cavity side, and there is a problem that appearance defects such as surface peeling due to material burning occur. Although the above-mentioned Japanese Patent Publication No. 7-10548 discloses that the nozzle block is provided with a temperature adjusting portion and a cooling hole to adjust the molten resin passing through the gate to a preferable state, such cooling In the form, when the plastic bond magnet material is targeted, cooling is insufficient, and more efficient cooling is required.

【0006】

[Purpose of Invention]

An object of the present invention is to easily and quickly replace wear-damaged parts even when handling a plastic bond magnet material that easily promotes wear of a resin passage in a hot runner type injection mold using a gate valve. The purpose is to provide an injection molding die that can be performed.

【0007】

[Means for solving problems]

The injection-molded mold according to the present invention has a fixed-side mold having a recess formed in a part of the parting surface and a fixed-side mold that is removably fixed to the recess of the fixed-side mold via an attachment / detachment means. A support block forming a part of the parting surface of the mold and a support block that is detachably fitted to the support block from the opposite side of the parting surface of the fixed-side mold to the fixed-side mold. A gate facing the parting surface includes a nozzle tip that opens at the tip, and the nozzle tip is sandwiched between the support block and a nozzle holder that is inserted into the support block via the fixed side mold, and the nozzle is inserted. The gate is opened and closed by a gate pin housed in a holder.

【0008】

According to the present invention, the molten resin is injected from the gate into a molding cavity formed between the fixed-side mold and the movable-side mold. When the injection work of the molten resin is completed, the gate is closed by the gate pin, and the mold is opened so that the movable mold is separated from the fixed mold. When the nozzle tip is worn, the support block is removed from the fixed side mold by the attachment / detachment means in this mold open state, the nozzle tip fitted to the support block is replaced with a new one, and then the support block is replaced again. It is fixed to the fixed side mold by the attachment / detachment means and the injection work is restarted.

【0009】

BEST MODE FOR CARRYING OUT THE INVENTION

In the injection molding die according to the present invention, the attachment / detachment means are attached to a bolt mounting hole opened in the parting surface of the support block, a female screw hole formed in the fixed side mold and communicating with the bolt mounting hole, and a bolt mounting hole. It has a bolt that is screwed into the female screw hole, or has a female screw portion formed on the inner peripheral surface of the recess of the fixed side mold and a male screw portion formed on the outer peripheral surface of the support block and screwed into the female screw portion. It may have. Alternatively, a locking convex portion that can appear and disappear in a direction parallel to the parting surface of the fixed-side mold, a driving means for driving the locking convex portion to appear and disappear, and a mechanism that the locking convex portion can engage with. A sphere having a retaining recess or capable of appearing in a direction parallel to the parting surface of the fixed-side mold, a ball plunger having a urging means for urging the sphere in a protruding direction, and a sphere of the ball plunger. It may have a locking recess that can be locked.

【0010】

The support block may further have temperature control means built in close proximity to the nozzle tip. In this case, the temperature adjusting means may be an electric heater or may have a temperature adjusting medium passage for passing a heat medium or a refrigerant.

【0011】

The recess of the fixed side mold further has a fitting recess formed with a conical tapered surface having a central axis perpendicular to the parting surface, and the support block is formed on the tapered surface of the fitting recess. On the other hand, it is possible to further have a fitting convex portion formed with a tapered surface that can be tightly fitted.

【0012】

The resin passing through the gate may contain magnetic powder. Such resins include, for example, Ba-based and Sr-based ferrite magnetic materials, rare earth magnetic materials such as Sm-Co-based and Nd-Fe-based, carbonyl iron powder, other metal or alloy powders, and arbitrary magnetism such as soft magnetic ferrite. Examples thereof include those produced from a pellet-shaped plastic bond magnet compound by mixing and kneading one or a combination of two or more body powders with a binder, for example, nylon.

【0013】

Other molding materials for which the present invention is particularly desirable include fiber-reinforced plastic materials, for example, high-density polyethylene mixed with heat-resistant fibers such as glass fiber, graphite fiber, and sapphire whisker, and heat-curable resin. Is filled with organic fiber, wood fiber, asbestos, etc., and as conductive plastics material, POM (polyoxymethylene) resin or PPS (polyphenylene sulfide) resin filled with carbon fiber can be mentioned. it can.

【0014】

[Example]

Examples of the injection molding die according to the present invention will be described in detail with reference to FIGS. 1 to 4, but the present invention is not limited to these examples, and the present invention may be further combined or patented in this specification. Any modification or modification included in the concept of the present invention described in the claims can be made, and therefore can be naturally applied to other techniques belonging to the spirit of the present invention.

【0015】

In Patent No. 3160874 (Patent No. 3090157), Japanese Patent Publication No. 5-33887, Japanese Patent Publication No. 7-67715, Japanese Patent Publication No. 7-10548, etc. Since the basic configurations of the injection molding apparatus in which the injection molding die is incorporated are disclosed, and these basic configurations are well known, the description of these parts which are not directly related to the present invention will be described. Is omitted, and only the main parts of the present invention will be described below.

【0016】

The cross-sectional structure of the main part in the first embodiment is shown in FIG. That is, a recess 12 is formed in the central portion of the parting surface Fp of the fixed side mold 11 facing the movable side mold (not shown). At the center of the recess 12, a fitting recess 13 having a conical tapered surface having a central axis perpendicular to the parting surface Fp is further formed. A support block 14 forming a part of the parting surface Fp of the fixed-side mold 11 is embedded in the recess 12 and the fitting recess 13. The support block 14 is formed with a fitting convex portion 15 having a tapered surface that can be closely fitted to the tapered surface of the fitting concave portion 13, whereby the support block 14 with respect to the fixed side mold 11 is formed. Positioning can be performed accurately. That is, the recess 12 and the fitting recess 13 of the fixed-side mold 11 have a shape substantially corresponding to the contour shape of the support block 14.

【0017】

A plurality of female screw holes 16 are formed at the bottom of the recess 12 of the fixed-side mold 11. A plurality of bolt mounting holes 18 for inserting bolts 17 that can be screwed into these female screw holes 16 are opened in the parting surface Fp of the support block 14, respectively. These bolt mounting holes 18 are, for example, stepped holes in which the heads of hexagon socket head bolts can be embedded, and are set so that the heads of the bolts 17 do not protrude from the parting surface Fp. These female screw holes 16, bolt mounting holes 18 and bolts 17 function as attachment / detachment means of the present invention. That is, by screwing the bolt 17 into the fixed-side mold 11 via the bolt mounting hole 18, the support block 14 can be integrally fixed to the fixed-side mold 11. On the contrary, the support block 14 can be removed from the fixed-side mold 11 by removing the bolt 17 from the female screw hole 16 of the fixed-side mold 11.

【0018】

A holder accommodating hole 20 capable of accommodating a nozzle holder 19 at the tip of a heating cylinder (not shown) via a fixed-side mold 11 is formed in the central portion of the support block 14. A nozzle tip 21 that can be removed from the opposite side of the parting surface Fp of the fixed-side mold 11 is fitted in the center of the bottom of the holder accommodating hole 20. At the tip of the nozzle tip 21, a gate 22 facing the parting surface Fp of the fixed-side mold 11 is opened. The nozzle tip 21 is sandwiched between the nozzle holder 19 and the support block 14 in a state of being fitted to the nozzle holder 19 described above. The nozzle tip 21 is in a state of being pressed against the bottom of the holder accommodating hole 20 by receiving the pressure of the molten resin interposed in the nozzle holder 19, but the nozzle tip 21 is pushed by the molten resin passing from the nozzle holder 19 to the gate 22. An appropriate play, that is, a gap Gp, is formed between the nozzle tip 21 and the nozzle holder 19 so as to allow thermal expansion.

【0019】

The outer peripheral surface of the nozzle holder 19 on which the water jacket 23 is formed is surrounded by the heater 25 covered with the heat insulating material 24 so that the nozzle holder 19 can be held at an appropriate temperature.

【0020】

A temperature control medium passage 26 is formed in the support block 14 in the vicinity thereof so as to surround the nozzle tip 21, and the temperature control medium passage 26 is used to hold the nozzle tip 21 at an appropriate temperature. A heat medium or refrigerant is allowed to flow. Water, oil, air, or the like can be used as the heat medium or the refrigerant. When it is not necessary to cool the nozzle tip 21, it is also effective to incorporate an electric heater in place of such a temperature control medium passage 26.

【0021】

The gate 22 is opened and closed by the reciprocating operation of the gate pin 27 incorporated in the nozzle holder 19, and the molten resin is supplied and supplied to a molding cavity (not shown) formed between the fixed-side mold 11 and the movable-side mold. The stop is done. In this case, it is desirable that the gate pin 27 is made of a material having a hardness lower than that of the nozzle tip 21, and the wear of the nozzle tip 21 is suppressed as much as possible.

【0022】

When hard particles such as magnetic powder are contained in the molten resin, the gate 22 portion of the nozzle tip 21 having a small passage cross-sectional area is worn away, so that the nozzle tip 21 and the gate pin 27 are worn at an appropriate time. Etc. need to be replaced. When replacing the nozzle tip 21, remove the bolt 17 in the mold open state, remove the support block 14 from the fixed side mold 11, and replace the nozzle tip 21 fitted to the bottom of the holder accommodating hole 20 with a new one. After replacing the nozzle tip 21, the support block 14 is fitted into the recess 12 and the fitting recess 13 of the fixed side mold 11 again, the nozzle holder 19 is introduced into the holder accommodating hole 20 of the support block 14, and the tip of the nozzle holder 19 is inserted. With the nozzle tip 21 fitted and held in place, the bolt 17 is screwed into the female screw hole 16 of the fixed-side mold 11, and the support block 14 is integrally fixed to the fixed-side mold 11.

【0023】

In the above-described embodiment, the support block 14 is detachably fixed to the fixed-side mold 11 by using a bolt 17, but such a bolt 17 or the like is adopted as the attachment / detachment means according to the present invention. In addition to the above, the following configurations can be adopted.

【0024】

FIG. 2 shows the cross-sectional structure of the portion of the support block 14 in another embodiment of the injection molding die according to the present invention. That is, a male screw portion 28 is formed on the outer peripheral surface of the support block 14, a female screw portion 29 to which the male screw portion 28 is screwed is formed on the inner peripheral surface of the recess 12 of the fixed side mold 11, and these male screw portions 28 and the female screw are formed. The attachment / detachment means is composed of the part 29. When attaching / detaching the support block 14 to / from the fixed mold 11, the outer circumference of the flange portion 30 formed on the parting surface Fp side of the support block 14 is gripped by using a jig (not shown) or the like to hold the support block 14. By rotating the entire 14 with respect to the fixed-side mold 11, the support block 14 can be attached to and detached from the fixed-side mold 11.

【0025】

In this embodiment, it is not necessary to open the bolt mounting hole 18 on the parting surface Fp of the support block 14 as in the previous embodiment, so only the flange portion 30 can be set to a large diameter as necessary on the movable side. Damage to the parting surface Fp of the mold can be avoided. In FIG. 2, the same reference numerals are given to the elements having the same functions as those in the previous embodiment.

【0026】

FIG. 3 shows the cross-sectional structure of the portion of the support block 14 in another embodiment of the injection molding die according to the present invention. That is, on the inner peripheral surface of the recess 12 of the fixed-side mold 11, an annular casing 31, a plurality of accommodating holes 32 formed radially with respect to the casing 31, and accommodating in these accommodating holes 32, respectively. A steel ball 33 that can appear and disappear from the inner peripheral surface of the casing 31 in a direction parallel to the parting surface Fp, and the steel ball 33 is housed in the accommodating hole 32 together with the steel ball 33, and the steel ball 33 is accommodated in the inner peripheral surface of the casing 31. A ball plunger 35 having a spring 34 urging in a direction protruding from the casing 35 is integrally incorporated, and the spring 34 can be retracted and moved outward in the radial direction of the casing 31 by a driving means (not shown). There is. Further, on the outer peripheral surface of the support block 14, a locking recess 36 is formed in which the spheres of the ball plunger 35 can be locked. Therefore, when the support block 14 is removed from the fixed-side mold 11, the spring 34 that urges the steel ball 33 to the locking recess 36 is retracted and moved to eliminate the spring force of the spring 34 with respect to the steel ball 33. Pull out the support block 14 from the fixed side mold 11 using its own weight. On the contrary, when the support block 14 is mounted on the fixed side mold 11, the spring 34 is advanced to the original urging position, and the steel ball 33 is projected from the inner peripheral surface of the casing 31. The support block 14 is inserted into the casing 31 against the force, and the steel ball 33 is locked in the locking recess 36 formed on the outer peripheral surface of the support block 14.

【0027】

Also in this embodiment, since it is not necessary to open the bolt mounting hole 18 in the parting surface Fp of the support block 14 as in the first embodiment, the parting surface Fp of the movable mold by such an opening is used. Damage can be avoided. In FIG. 3, the same reference numerals are given to the elements having the same functions as those in the previous embodiment.

【0028】

FIG. 4 shows the cross-sectional structure of the portion of the support block 14 in still another embodiment of the injection molding die according to the present invention. That is, the annular casing 31 is integrally incorporated in the inner peripheral surface of the recess 12 of the fixed-side mold 11. A plurality of accommodating holes 32 are formed radially in the casing 31. In these accommodating holes 32, locking claws 37 that can appear and disappear from the inner peripheral surface of the casing 31 in a direction parallel to the parting surface Fp are accommodated. A driving means (not shown) for reciprocally driving the locking claw 37 in the accommodating hole 32 is connected to the locking claw 37. The drive means may be of a scroll type in which the locking claws 37 appear and disappear by turning the outer circumference of the hydraulic mechanism or the casing 31. Locking recesses 36 are formed on the outer peripheral surface of the support block so that the tips of the locking claws 37 can be locked. Therefore, when the support block 14 is removed from the fixed-side mold 11, the locking claw 37 is returned to the accommodating hole 32 by operating the driving means, so that the locking claw 37 with respect to the locking recess 36 of the support block 14 The engaged state is released, and the support block 14 can be removed from the fixed-side mold 11 by using its own weight or the like. On the contrary, when mounting the support block 14 on the fixed side mold 11, the support block 14 is inserted into the casing 31 with the locking claw 37 returned to the accommodating hole 32, and the driving means is operated in this state. By operating, the locking claw 37 is projected to the locking recess 36 of the support block 14 and these are switched to the engaged state, so that the support block is integrally connected to the fixed side mold 11.

【0029】

Also in this embodiment, since it is not necessary to open the bolt mounting hole 18 in the parting surface Fp of the support block 14 as in the first embodiment, the parting surface Fp of the movable mold by such an opening Damage can be avoided. In FIG. 4, the same reference numerals are given to the elements having the same functions as those in the previous embodiment.

【0030】

[Effect of the invention]

According to the injection molding die of the present invention, a recess is formed in a part of the parting surface of the fixed side mold, and the support block forming a part of the parting surface of the fixed side mold is formed in the fixed side mold. Removably fixed to the recess via a detachable means, and the nozzle tip with the gate facing the parting surface of the fixed side mold opening at the tip is removed from the opposite side of the parting surface of the fixed side mold with respect to the support block. The nozzle tip is sandwiched between the support block and the nozzle holder that is inserted into the support block via the fixed side mold, and the gate is opened and closed by the gate pin housed in this nozzle holder. , When the nozzle tip is worn, remove the worn nozzle tip from the support block by removing the nozzle holder from the support block and removing the support block from the fixed side mold using the attachment / detachment means to remove the worn nozzle tip from the support block and use a new nozzle tip. Can be installed easily and quickly. In particular, when the resin passing through the gate contains a hard material such as magnetic powder, it is necessary to frequently replace the nozzle tip due to wear, but this replacement work should be performed more easily and quickly. Can be done.

【0031】

A bolt mounting hole that the attachment / detachment means opens on the parting surface of the support block, a female screw hole that is formed on the fixed side mold and communicates with the bolt mounting hole, and a bolt that is mounted on the bolt mounting hole and screwed into the female screw hole. When holding, the bolts can be pulled out and tightened from the parting surface side, so that the workability of attaching and detaching the support block to the fixed side mold can be kept better.

【0032】

When the attachment / detachment means has a female screw portion formed on the inner peripheral surface of the concave portion of the fixed side mold and a male screw portion formed on the outer peripheral surface of the support block and screwed into the female screw portion, the fixed side mold is used. On the other hand, by rotating the support block, it is possible to easily attach / detach the support block to the fixed side mold, and since a part of the attachment / detachment means is not exposed on the parting surface, the party of the movable side mold. Damage to the surface can be prevented.

【0033】

A locking convex portion in which the attachment / detachment means can appear and disappear in a direction parallel to the parting surface of the fixed-side mold, a driving means for driving the locking convex portion in and out, and the locking convex portion can be engaged with each other. When the locking recess is provided, the locking protrusion can be made to appear and disappear by the driving means, so that the support block can be easily attached to and detached from the fixed side mold, and a part of the attaching / detaching means can be attached to the parting surface. Is not exposed, so damage to the parting surface of the movable mold can be prevented.

【0034】

A ball plunger having a sphere whose attachment / detachment means can appear and disappear in a direction parallel to the parting surface of the fixed-side mold and an urging means for urging the sphere in a protruding direction, and a sphere in which the sphere of the ball plunger can be locked. When it has a retaining recess, the support block can be easily attached to and detached from the fixed side mold against the urging force by the urging means without using a special drive source, and the parting surface. Since a part of the attachment / detachment means is not exposed, damage to the parting surface of the movable mold can be prevented.

【0035】

When an electric heater or a temperature adjusting means having a temperature adjusting medium passage for passing a heat medium or a refrigerant is incorporated in the support block in the vicinity of the nozzle tip, the molten resin or the fixed side interposed in the gate and its vicinity is installed. The temperature inside the resin passage and the cavity formed between the mold and the movable mold can be adjusted to the optimum temperature, and appearance defects such as burning due to overheating can be eliminated.

【0036】

A fitting recess formed with a conical tapered surface having a central axis perpendicular to the parting surface of the fixed-side mold is further provided in the recess of the fixed-side mold, and is tightly closed to the tapered surface of the fitting recess. When the support block is further provided with a fitting convex portion having a tapered surface formed into the support block, the support block can be positioned with respect to the fixed-side mold extremely accurately and quickly.

[Simple explanation of drawings]

[Figure 1]

It is sectional drawing which shows the schematic structure of the main part in one Example of the injection molding die by this invention.

[Figure 2]

It is sectional drawing which shows the schematic structure of the main part in another Example of the injection molding die by this invention.

[Fig. 3]

It is sectional drawing which shows the schematic structure of the main part in another Example of the injection molding die by this invention.

[Fig. 4]

It is sectional drawing which shows the schematic structure of the main part in still another Example of the injection molding die by this invention.

[Explanation of symbols]

11 Fixed side mold 12 recess 13 Fitting recess 14 Support block 15 Fitting convex part 16 Female screw hole 17 volt 18 Bolt mounting holes 19 Nozzle holder 20 Holder storage hole 21 Nozzle tip 22 Gate 23 water jacket 24 insulation 25 heater 26 Temperature control medium passage 27 Gate pin 28 Male thread 29 Female thread 30 Flange part 31 casing 32 containment hole 33 steel ball 34 spring 35 ball plunger 36 Locking recess 37 Locking claw Fp parting surface Gp gap