JP5041963B2 - Mold structure for injection molding - Google Patents

Description

  The present invention relates to an injection mold structure used when molding a molded product, particularly a skid constituting a synthetic resin pallet or a welding pallet by a counter pressure method.

  Conventionally, before the molten resin is injected into the cavity, a compressed gas is injected into the cavity so that the inside of the cavity is in a pressurized state, and then the molten resin is injected into the cavity while the inside of the cavity is maintained in a pressurized state. Thus, injection molding by the so-called counter pressure method for forming a product is known. By this counter pressure method, the surface layer (skin layer) is in a non-foamed state and the inside is foamed uniformly. The product in a state can be molded.

  Also, as disclosed in Patent Document 1, a slide core is used to form the undercut portion. By the counter pressure method as described above, a synthetic resin pallet having an undercut portion, etc. When the molded product is molded, since the slide core disposed between the movable mold and the fixed mold is exposed to the outside, the contact surface between the movable mold and the slide core and the slide It is necessary to arrange packing on the contact surface between the core and the fixed mold to maintain the airtight state between the movable mold and the slide core and between the slide core and the fixed mold. In this way, leakage of the compressed gas supplied into the cavity is prevented in the mold clamping state.

Japanese Patent Laid-Open No. 9-109199

  As described above, since the slide core is exposed to the outside, there is a problem that the compressed gas supplied into the cavity leaks from the contact surface between the slide core and the movable mold.

  Further, as described above, in order to dispose packing on the contact surface between the movable mold and the slide core and the contact surface between the slide core and the fixed mold, the movable mold, the fixed mold, and the slide core are provided. Therefore, it is necessary to form a groove or the like for inserting the packing, and therefore there is a problem that the processing cost of the mold, and thus the cost of the injection mold structure itself increases.

  Furthermore, even if packing is provided on the contact surface between the movable mold and the slide core and the contact surface between the slide core and the fixed mold, the slide core slides along the movable mold and the fixed mold. Therefore, it is difficult to maintain airtightness during mold clamping, and frequent maintenance and replacement of the packing are required to maintain airtightness. There is a problem of becoming.

  An object of the present invention is to solve the problems of the conventional injection mold structure described above.

  In order to achieve the above-described object, the present invention injects a molten resin into a cavity in a state in which compressed gas is injected into a cavity formed by an ejector box hermetic space and a movable mold and a fixed mold. In the mold structure for injection molding for molding a molded product composed of a non-foamed surface layer and an internal foamed portion, first, a shielding side wall is formed on the stationary mold backing plate, and the mold is clamped In this embodiment, the slide core is hermetically sealed by the stationary mold receiving plate and the movable mold receiving plate by configuring the shielding side wall of the stationary mold receiving plate and the movable mold receiving plate to contact each other. Secondly, a cooling member for cooling the slide core is provided across the slide core and the movable mold receiving plate.

  By forming a shielding side wall on the stationary mold receiving plate, and in a mold-clamped state, the sliding sidewall is fixed by configuring the shielding side wall of the stationary mold receiving plate and the movable mold receiving plate to contact each other. Because the mold receiving plate and the movable mold receiving plate are configured to be hermetically surrounded, the cavity and the movable mold receiving plate are inserted between the clamped fixed mold receiving plate and the movable mold receiving plate. It is possible to prevent the compressed gas injected into the ejector box airtight space from leaking.

  Since the cooling member for cooling the slide core is disposed across the slide core and the movable mold receiving plate, the fixed mold receiving plate and the movable mold receiving plate on which the shielding side wall is formed are provided. The slide core surrounded in an airtight manner can be effectively cooled.

  Hereinafter, examples of the present invention will be described. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

  First, an injection mold structure for molding a skid constituting a welding pallet will be outlined as an example with reference to FIGS.

  First, an outline of a movable side portion such as a movable mold of an injection mold structure will be described.

  1 is a movable side mounting plate, 2 is a movable mold receiving plate, and 3 is a cylindrical ejector attached between the movable side mounting plate 1 and the movable mold receiving plate 2. Is a box. Reference numeral 4 denotes a guide rod attached so as to bridge the movable side mounting plate 1 and the movable mold receiving plate 2. S is a slide core disposed on the movable mold receiving plate 2 so as to be slidable.

  Reference numeral 5 denotes an ejector plate housed in an airtight space (hereinafter referred to as an ejector box airtight space) A1 surrounded by the movable side mounting plate 1, the movable mold receiving plate 2 and the ejector box 3. A guide rod 4 is inserted into a through hole 5 a formed in the plate 5 via a bush 6. Reference numeral 5b denotes an ejector rod attached to the surface of the ejector plate 5 located on the opposite side of the movable mold receiving plate 2. The ejector rod 5b is a through-hole formed in the movable-side mounting plate 1. It is inserted in 1a. Reference numeral 5 c denotes an ejector pin attached to the ejector plate 5. The ejector rod 5b is configured to reciprocate by a cylinder member or the like (not shown). In addition, 1b is a cylindrical guide cylinder attached to the surface of the movable side mounting plate 1 located in the ejector box airtight space A1 so as to surround the through hole 1a formed in the movable side mounting plate 1. The ejector rod 5b is inserted into the guide cylinder 1b.

  Reference numeral 7 denotes a movable mold attached to the movable mold receiving plate 2. In this embodiment, the movable mold 7 is divided into a plurality of divided molds 7a. And is incorporated in a recess 2a formed in the movable mold receiving plate 2.

  The ejector box 3 located in the vicinity of the guide rod 4 is provided with a grease injection through hole 3a communicating with the ejector box airtight space A1. 8 is a sealing lid for closing the grease injection through hole 3a. Bolt insertion holes 8a are formed at four corners of the sealing lid 8, and an ejector located near the grease injection through hole 3a. The outer wall of the box 3 is formed with a screw hole 3b into which the tip end of the bolt B inserted into the bolt insertion hole 8a of the sealing lid 8 is screwed.

  As described above, the guide rod 4 is configured to be inserted into the through hole 5 a formed in the ejector plate 5 via the bush 6. However, the guide rod 4 is formed on the inner peripheral surface of the cylindrical bush 6. In the circumferential direction, a plurality of grease grooves 6 a are formed. By filling the grease grooves 6 a with grease, the ejector plate 5 smoothly reciprocates with respect to the guide rod 4. It is configured to be able to.

  As will be described later, compressed gas is injected into the ejector box hermetic space A1 surrounded by the movable side mounting plate 1, the movable mold receiving plate 2 and the ejector box 3 every time the product is molded. However, in this repeated compressed gas injection process, the grease is pushed out from the grease groove 6a formed on the inner peripheral surface of the cylindrical bush 6, and the ejector plate 5 cannot smoothly reciprocate. The problem will arise.

  In order to solve the above-described problems, it is necessary to periodically supply grease to the grease groove 6a formed on the inner peripheral surface of the cylindrical bush 6, but a conventional injection mold In the structure, it is necessary to disassemble the mold structure for injection molding in order to supply grease, and it takes considerable time and labor to supply grease.

  In this embodiment, when replenishing grease to the grease groove 6 a formed on the inner peripheral surface of the cylindrical bush 6, the sealing lid 8 is removed by removing the bolt B attached to the outer wall of the ejector box 3. Accordingly, as shown in FIG. 4, the grease injection through hole 3 a formed in the ejector box 3 is opened, and the sprayed grease is passed through the grease injection through hole 3 a to the guide rod 4. By spraying, the grease to the grease groove 6a can be replenished easily and in a short time. If the ejector plate 5 is located near the grease injection hole 3a, the sprayed grease cannot be effectively attached to the guide rod 4, so that as shown in FIG. It is preferable to spray the grease in a state where the ejector plate 5 is not positioned in the grease injection through hole 3a.

  Next, with reference to FIG. 1 and FIG. 5, an outline of a fixed side portion such as a fixed mold of an injection mold structure will be described.

  Reference numeral 10 denotes a fixed-side attachment plate, and 11 denotes a fixed mold receiving plate attached to the fixed-side attachment plate 10. Reference numeral 12 denotes a fixed mold. In the present embodiment, the fixed mold 12 is incorporated in a recess 11 a formed in the fixed mold receiving plate 11. Note that the fixed mold 12 can also be divided into a plurality of divided molds as necessary, similarly to the movable mold 7. K is a known angular pin arranged on the stationary mold receiving plate 11, and the angular pin K includes a movable mold 7 and a stationary mold 12 as shown in FIG. 5. It is configured to be inserted into a through hole s1 formed in the slide core S when the abutted mold clamping is performed.

  Reference numeral 13 denotes a plurality of nozzles disposed in the fixed side portion of the injection mold structure. The molten resin is inserted into the cavity C formed by the movable mold 7 and the solid mold 12 via the nozzle 13. Will be injected.

  Next, a compressed gas injection structure for injecting compressed gas into the cavity C and the ejector box airtight space A1 will be described.

  3c is an ejector box side passage formed in the ejector box 3 for injecting compressed gas into the ejector box airtight space A1, and the ejector box side passage 3c is compressed via a switching valve (not shown). A pipe p1 connected to the gas supply source is attached. Reference numeral 2b denotes a movable mold side passage formed in the movable mold receiving plate 2 for injecting compressed gas into the cavity C from the movable mold 7 side. The movable mold side passage 2b includes A pipe p2 connected to the compressed gas supply source is attached via a switching valve (not shown). Reference numeral 11b denotes a fixed mold side passage formed in the fixed mold receiving plate 11 and the solid mold 12 for injecting compressed gas into the cavity C from the fixed mold 12 side. A pipe p3 connected to a compressed gas supply source is attached to the side passage 11b via a switching valve (not shown).

  The pipes p1 to p3 are connected to a switching valve (not shown), and the switching valve stops the compressed gas supply position for supplying the compressed gas to the pipes p1 to p3 and the supply of the compressed gas to the pipes p1 to p3. The compressed gas supply stop position to be switched and the natural exhaust position where the pipes p1 to p3 communicate with the atmosphere can be switched.

  Next, a skid molding process using the above-described injection mold structure will be described.

  As shown in FIG. 5, with the mold clamped state in which the movable mold 7 and the fixed mold 12 are joined, first, the ejector box airtight space is first passed from the ejector box side passage 3c via the pipe p1. Compressed gas is supplied to A1. Further, when compressed air is supplied to the movable mold side passage 2b through the pipe p2, the compressed gas constitutes the contact gap G1 between the movable mold receiving plate 2 and the movable mold 7 and the movable mold 7. When the compressed air is supplied to the cavity C through the contact gap G2 between the split molds 7a and further supplied to the cavity C through the pipe p3, the compressed gas is exchanged with the movable mold 7a. It will be supplied to the cavity C through the parting surface with the fixed mold 12. In this way, the ejector box hermetic space A1 and the cavity C are filled with the compressed gas.

  As described above, after the ejector box hermetic space A1 and the cavity C are filled with the compressed gas, the switching valve is switched to the compressed gas supply stop position for stopping the supply of the compressed gas to the pipes p1 to p3. Molten resin is injected into the cavity C from the nozzle 13. When about 60 to 90% of the molten resin is injected into the cavity C, the switching valve is switched from the compressed gas supply stop position to the natural exhaust position where the pipes p1 to p3 communicate with the atmosphere. The compressed gas inside is discharged to the atmosphere.

  Thereafter, the movable side mounting plate 1, the movable mold receiving plate 2, the ejector box 3, the movable mold 7, etc. are moved to the fixed side mounting plate 10 or the fixed mold receiving portion. The movable mold 7 is released from the fixed mold 12 by separating from the fixed side portion of the injection mold structure including the plate 11 and the fixed mold 12. Next, as shown in FIG. 6, the ejector plate 5 at a substantially intermediate position between the movable side mounting plate 1 and the movable mold receiving plate 2 is moved to a movable mold as shown in FIG. The ejector pin 5 c is pushed out of the movable mold 7 by moving in the direction of the receiving plate 2, and the injection-molded skid is removed from the movable mold 7. In this way, the skid is formed.

  Next, more specific structures and arrangements of the stationary mold receiving plate 11, the slide core S, and the movable mold receiving plate 2 will be described with reference to FIGS.

  As shown in FIG. 5, the fixed mold receiving plate 11 has an outer peripheral portion of the fixed mold receiving plate 11 extending in the direction of the movable mold receiving plate 2. A shielding side wall 11c is formed so as to cover the slide core S in a clamped state in which the stationary mold 12 is in contact with the stationary mold 12. On the outer peripheral wall surface s2 of the slide core S, an inclined surface inclined inward from the movable mold receiving plate 2 toward the fixed mold 12 (hereinafter, this outer peripheral wall surface s2 is referred to as an inclined outer peripheral wall surface) is formed. Corresponding to the inclined outer peripheral wall surface s2 of the slide core S, the inner peripheral wall surface 11c1 of the shielding side wall 11c formed on the stationary mold receiving plate 11 also faces the movable mold 7 from the fixed side mounting plate 10. Thus, an inclined surface that is inclined outward (hereinafter, the inner peripheral wall surface 11c1 is referred to as an inclined inner peripheral wall surface) is formed.

  As shown in FIGS. 5 and 8, in the mold clamping state, the inner peripheral wall surface 11c1 of the shielding side wall 11c formed on the stationary mold receiving plate 11 and the inclined outer peripheral wall surface s2 of the slide core S are in contact with each other. The front end surface 11c2 of the shielding side wall 11c formed on the stationary mold receiving plate 11 and the front end surface 2c of the movable mold receiving plate 2 are in contact with each other. With this configuration, the compressed gas injected into the cavity C and the ejector box hermetic space A1 leaks from between the clamped stationary mold receiving plate 11 and the movable mold receiving plate 2. This can prevent anything.

  A circumferential groove 11c3 is formed in the front end surface 11c2 of the shielding side wall 11c formed on the stationary mold receiving plate 11, and a packing v1 is fitted in the circumferential groove 11c3. As shown in FIG. 8, in the mold clamping state, the packing v <b> 1 fitted in the circumferential groove 11 c <b> 3 abuts on the front end surface 2 c of the movable mold receiving plate 2, and the fixed mold receiving plate 11 is brought into contact with it. The airtightness between the front end surface 11c2 of the formed shielding side wall 11c and the front end surface 2c of the movable mold receiving plate 2 is improved. Therefore, the compressed gas injected into the cavity C and the ejector box airtight space A1 is reduced. Leakage can be reliably prevented.

  As described above, the shielding side wall 11c is formed on the stationary mold receiving plate 11, and in the mold clamping state, the shielding side wall 11c of the stationary mold receiving plate 11 and the movable mold receiving plate 2 come into contact with each other. By configuring as above, the slide core S is configured to be hermetically surrounded by the stationary mold receiving plate 11 and the movable mold receiving plate 2. It is not necessary to form a recessed groove for inserting the packing in the fixed mold or the slide core. Therefore, it is possible to reduce the processing cost of the mold, and hence the cost of the injection mold structure itself.

  In addition, since no packing is provided on the contact surface between the movable mold and the slide core and the contact surface between the slide core and the fixed mold, the wear of the packing causes the airtightness of the injection mold structure. Therefore, the maintenance and management work of the packing can be omitted, and the maintenance and management work of the mold structure for injection molding can be reduced.

  By the way, as described above, by configuring the shielding side wall 11c of the stationary mold receiving plate 11 and the movable mold receiving plate 2 to be in contact with each other, the slide core S has the shielding side wall in the mold clamping state. Since the stationary mold receiving plate 11 and the movable mold receiving plate 2 formed with 11c are hermetically surrounded, a cooling member is disposed on the slide core S, and the slide core S is attached to the slide core S. It is preferable to cool.

  Below, the cooling member H1 for cooling the slide core S is demonstrated using FIG.9 and FIG.10.

  s3 is a coolant channel formed in the slide core S through which the coolant circulates. Reference numeral 2d denotes a space formed in the movable mold receiving plate 2, and the space 2d extends from the outer peripheral side wall surface 2e of the movable mold receiving plate 2 toward the inside of the movable mold receiving plate 2. The vertical hole 2d1 is present, and the horizontal hole 2d2 extends from the tip of the vertical hole 2d1 to the coolant channel s3 formed in the slide core S.

  h1 is a flexible hose, and the tip of the flexible hose h1 is connected to an elbow joint h2, and the elbow joint h2 is a coolant channel formed in the slide core S via a rigid connecting pipe h3. It is linked to s3. h4 is a lid for closing the space 2d formed in the movable mold receiving plate 2, and the lid h4 is attached to the movable mold receiving plate 2 by a bolt B through a washer h5. The flexible hose h1 is airtightly fitted in a through hole (not shown) formed in the lid h4 and the washer h5. A coolant supply hose h7 is connected to the end of the flexible hose h1 located on the side opposite to the elbow joint h2 via a hose attachment base h6. Note that h8 is a well-known attachment nut for attaching the hose attachment h6 to the lid h4 and the washer h5.

  As shown in FIG. 5 and FIG. 10, there is no gap between the slide core S and the movable mold 7 in the mold clamping state, and the slide core S is in contact with the movable mold 7. . Further, in the mold opening process in which the movable mold 7 is separated from the fixed mold 12, as is well known, the slide core S is disposed on the stationary mold receiving plate 11, and the tip portion thereof is the slide core. While being guided by the angular pin K inserted in the through hole s1 formed in S, it slides outward along the movable mold receiving plate 2, and as shown in FIG. A gap D <b> 1 is formed between the slide core S and the movable mold 7.

  In the mold opening process, as is well known, the slide core S moves outward. Therefore, the lid h4 attached to the movable mold receiving plate 2 and the rigid connecting pipe h3 are used. Although the space | interval with the elbow joint h2 attached to the slide core S becomes narrow, since the elbow joint h2 and the cover body h4 are connected by the flexible hose h1 which has flexibility, it shows in FIG. The elbow joint h2 attached to the slide core S via the lid h4 and the connecting pipe h3 due to the flexible hose h1 being bent as shown in FIG. The narrowing of the interval can be absorbed.

  As described above, since the cooling member H1 can be disposed across the movable mold receiving plate 2 and the slide core S that slides and moves along the movable mold receiving plate 2, the shielding member H1 is shielded. The slide core S surrounded in an airtight manner can be effectively cooled by the stationary mold receiving plate 11 and the movable mold receiving plate 2 in which the side wall 11c is formed.

  v2 is a packing disposed on the contact surface between the lid h4 and the movable mold receiving plate 2, and the packing v2 is a groove 2e1 formed on the outer peripheral side wall surface 2e of the movable mold receiving plate 2. Is inserted. By arranging such a packing v2, the compressed gas injected into the cavity C or the ejector box airtight space A1 leaks from the contact surface between the lid h4 and the movable mold receiving plate 2. Can be prevented.

  Next, the cooling member H2 of the other Example for cooling the slide core S is demonstrated using FIGS. 11-13.

  In this embodiment, the slide core S is configured to slide and move along a guide recess 2f formed in the movable mold receiving plate 2 that extends in the sliding movement direction of the slide core S. ing. The movable mold receiving plate 2 is provided with a vertical hole 2g communicating with the guide recess 2f, and a hard pipe 2h is slidably fitted into the vertical hole 2g. Similarly to the above-described embodiment, the movable mold receiving plate 2 has a cover h4 for closing the vertical hole 2g formed in the movable mold receiving plate 2 via a washer h5. By B, it is attached to the movable mold receiving plate 2. The hard pipe 2h is fitted into a through hole h4a formed in the lid h4 and a through hole h5a formed in the washer h5. In addition, since the attachment of the coolant supply hose h7 to the hard pipe 2h is the same as that in the above-described embodiment, the description thereof is omitted.

  s4 is a coolant channel formed in the slide core S through which the coolant circulates, and the coolant supply port of the coolant channel s4 communicates with the hard pipe 2h.

  A circumferential groove h4c is formed in a surface h4b of the lid h4 that contacts the outer peripheral side wall surface 2e of the movable mold receiving plate 2. A packing v3 is fitted in the circumferential groove h4c. This packing v3 is provided between the outer peripheral side wall surface 2e of the movable mold receiving plate 2 and the lid h4 that comes into contact with the outer peripheral side wall surface 2e of the movable mold receiving plate 2 so that the cavity C and the ejector box airtight space A1. It has a function of preventing the compressed gas injected therein from leaking.

  A circumferential groove h4d is formed on the inner peripheral surface of the through hole h4a drilled in the lid h4, and a packing v4 is fitted in the circumferential groove h4d. The packing v4 is formed between the inner peripheral surface of the through hole h4a formed in the lid h4 and the outer peripheral surface of the hard pipe 2h fitted in the through hole h4a formed in the lid h4. C and the ejector box have a function of preventing the compressed gas injected into the airtight space A1 from leaking.

  In the mold clamping state, as shown in FIG. 12, the slide core S and the movable mold 7 are in contact with each other, and between the slide core S and the movable mold receiving plate 2, A gap D2 is formed. In the mold open state, as shown in FIG. 13, a gap D <b> 3 is formed between the slide core S and the movable mold 7.

  When the slide core S slides between the mold-clamped state and the mold-opened state, the hard pipe 2h is drilled in the vertical hole 2g formed in the movable mold receiving plate 2 and the lid body h4. Since the through hole h4a and the through hole h5a formed in the washer h5 are configured to be slidable, the stationary mold receiving plate 11 and the movable mold in which the shielding side wall 11c is formed. The slide core S enclosed in an airtight manner can be effectively cooled by the receiving plate 2.

FIG. 1 is a vertical sectional view of the mold structure for injection molding according to the present invention in an open state. FIG. 2 is an enlarged vertical sectional view of a main part of FIG. FIG. 3 is a perspective view of a sealing lid or the like constituting the injection mold structure of the present invention. FIG. 4 is an enlarged vertical sectional view of the main part similar to FIG. FIG. 5 is a vertical sectional view of the mold structure for injection molding according to the present invention in a clamped state. FIG. 6 is a vertical cross-sectional view of the mold structure for injection molding according to the present invention in an open state. FIG. 7 is an enlarged vertical sectional view of a main part of FIG. FIG. 8 is an enlarged vertical sectional view of the main part of FIG. FIG. 9 is an enlarged vertical sectional view of the vicinity of the cooling member disposed in the injection mold structure of the present invention. FIG. 10 is an enlarged vertical sectional view of the vicinity of the cooling member disposed in the injection mold structure of the present invention. FIG. 11 is an enlarged vertical sectional view of the vicinity of the cooling member of another embodiment disposed in the injection mold structure of the present invention. FIG. 12 is also an enlarged vertical sectional view of the vicinity of the cooling member of another embodiment disposed in the injection mold structure of the present invention. FIG. 13 is also an enlarged vertical sectional view of the vicinity of the cooling member of another embodiment disposed in the injection mold structure of the present invention.

Explanation of symbols

A1 ... Ejector box airtight space H1, H2 ... Cooling member K ...・ ・ ・ ・ Angular pin S ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Slide core p1 to p3 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Piping v1 to v4 ················································· Movable side mounting plate 2 Base plate 3 ... Ejector box 5 ... Ejector plate 7 ... ························································································· Fixed plate 11・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Fixed Mold receiving plate 12 .................. Fixed mold

Claims (2)

  By injecting molten resin into the cavity in a state where compressed gas is injected into the cavity formed by the ejector box airtight space and the movable mold and the fixed mold, the foamed surface layer and the internal foamed part are separated from each other. In a mold structure for injection molding for forming a molded product to be formed, a shielding side wall is formed on the stationary mold receiving plate, and in a clamped state, the shielding sidewall of the stationary mold receiving plate and the movable mold are used. The injection is characterized in that the slide core is hermetically surrounded by the stationary mold receiving plate and the movable mold receiving plate by being configured such that the receiving plate abuts on the receiving plate. Mold structure for molding.   The injection mold structure according to claim 1, wherein a cooling member for cooling the slide core is disposed across the slide core and the movable mold receiving plate. .

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