JP2017222097A - Mold apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate poor molding caused by a decrease in the temperature of molten resin.SOLUTION: In a mold apparatus, a retention member 80 is fixed on second molds 42, 70 so as to partly protrude to a cavity 12 having an annular shape, a metal component 93 having an annular shape is positioned and retained at the retention member 80 and the second molds 42, 70, a first mold 22 and the second molds 42, 70 are brought in contact with each other, and molten resin is allowed to flow into the cavity 12 in order of a first supply passage 16B that has an annular shape and extends in an axial direction, a second supply passage 16A that has an annular shape and extends in an axial direction and an outer diameter direction, and a gate 18 that has an annular shape and extends in an axial direction, thereby molding, in the cavity 12, a resin product 93 of which an inner peripheral side is provided with a metal component 93 and an outer peripheral side is provided with a resin component 92. An annular recess 67 is formed in an end face, closer to the retention member 80, of a core cylinder 60, a heat insulating material 68 having an annular shape is arranged on the annular recess 67, and the metal component 93 is brought in contact with the heat insulating material 68 to prevent the heat of the core cylinder 60 from transferring to the metal component 93 when the first mold 22 and the second mold 42 are brought in contact with each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mold apparatus for injection molding having an annular gate.

  When an annular resin product is injection-molded by a mold device for injection molding, the gate for supplying the molten resin to the cavity forming the resin product is at one point on the circumference of the cavity formed in the annular shape. In some cases, there is a problem that a resin confluence point called a weld is formed by injection molding, and a part that is extremely weaker than other parts is formed in the product.

  In the ring valve gate mold of Patent Document 1, a cylindrical core cylinder, a cylindrical valve probe, a cylindrical sleeve body, and a first mold are arranged in order from the inner diameter side to the outer diameter side. A gate that forms a first supply passage extending in the axial direction between the probe and a second supply passage extending in the axial direction and in the outer diameter direction, and is a cylindrical space extending in the axial direction between the core cylinder and the first mold. The sleeve is inserted into and removed from the gate, and a cavity that is an annular space with the first mold is formed in the second mold that approaches and separates from the first mold in the axial direction. Two molds are brought into contact with each other, and a molten resin is caused to flow into the cavity in the order of the first supply passage, the second supply passage, and the gate, thereby forming an annular resin product in the cavity and preventing welds from occurring.

  A worm wheel is considered as an annular resin product. The worm wheel has a resin part on the outer peripheral side in order to reduce the meshing noise with the worm, and a metal part on the inner peripheral side in order to transmit the rotational force to the rotary shaft on the inner peripheral side.

Japanese Patent Laid-Open No. 2015-112728

  In order to position and hold the cylindrical metal part in the radial direction, the holding member is fixed to the second mold so that a part projects into the cavity, the metal part is fitted into the holding member, and the metal part is positioned in the axial direction. In order to hold, it is considered that the metal part is sandwiched between the core cylinder and the second mold of the first mold by the contact between the second mold and the first mold.

  The metal part before insertion has a temperature close to the atmosphere, and the metal part is inserted into the cavity every time of injection molding and discharged from the cavity as a resin product. Therefore, every time the metal part contacts the core cylinder, Heat escapes to metal parts. A molding defect occurs due to a decrease in the molten resin temperature.

  An object of the present invention is to prevent the heat of the core cylinder from escaping to the metal parts, and eliminate molding defects due to a decrease in molten resin temperature.

According to a first aspect of the present invention, there is provided a core cylinder, a first supply passage which is disposed on an outer periphery of the core cylinder and extends in the axial direction with the core cylinder, and a second supply passage which extends in the axial direction and in the outer diameter direction. A valve probe to be formed; a first mold that is disposed on an outer periphery of the core cylinder and forms a gate that is a cylindrical space extending in the axial direction with the core cylinder; and an axial direction to be inserted into and removed from the gate. A moving sleeve body, a second mold that is close to and away from the first mold in the axial direction, and forms a cavity that is an annular space with the first mold, and a part that protrudes into the cavity A holding member that is fixed to the second mold and that positions and holds the metal part of the annular resin product in the axial direction and the radial direction with the second mold, and the annular member is disposed on the holding member and the second mold. Metal part Positioning and holding the first mold and the second mold close to each other, and flowing the molten resin into the cavity in the order of the first supply passage, the second supply passage, and the gate, thereby the metal part on the inner peripheral side. A mold apparatus in which a resin product having a resin part on the outer peripheral side is molded in the cavity,
An annular recess is formed in the end surface of the core cylinder on the holding member side, an annular heat insulating material is disposed in the annular recess, and the metal part is moved when the first mold and the second mold are brought close to each other. The said heat insulating material is arrange | positioned in the position which contacts.

  According to the configuration of the present invention, the core cylinder has a temperature close to that of the molten resin, the metal part before being inserted into the cavity has a temperature close to the atmosphere, and the temperature of the core cylinder is higher than the metal part of the resin product. Even if the metal part is clamped between the core cylinder and the second mold in the axial direction, the heat of the core cylinder can be prevented from escaping to the metal part of the resin product by the heat insulating material, and molding defects due to a decrease in the molten resin temperature can be eliminated. it can.

It is sectional drawing which shows the state after the injection | emission of the metal mold | die apparatus which concerns on one Embodiment of this invention. It is the sectional view on the AA line of FIG. 1 which concerns on one Embodiment of this invention. It is sectional drawing which shows the mold open state of the metal mold apparatus which concerns on one Embodiment of this invention. It is a state figure which takes out a resin product from a metallic mold device concerning one embodiment of the present invention. It is a state figure which inserts a metal component in the metallic mold apparatus concerning one embodiment of the present invention. It is sectional drawing which shows the mold closing state of the metal mold apparatus which concerns on one Embodiment of this invention. FIG. 5 is a cross-sectional view showing a state during injection of the mold apparatus according to the embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  One embodiment of the present invention is a ring valve gate mold apparatus 10 (hereinafter referred to as a mold apparatus 10) for molding a relatively large-diameter annular (ring-shaped) resin product. As a resin product in which a cylindrical metal part is inserted on the inner peripheral side, for example, there is a worm wheel 90. The worm wheel 90 has a resin part 92 integrally formed on the outer peripheral side to reduce the meshing noise with the worm, and a cylindrical part on the inner peripheral side of the resin part 92 to transmit the rotational force to the rotary shaft on the inner peripheral side. A metal part 93 is inserted. A gear 91 is formed on the outer periphery of the resin component 92 by injection molding.

  FIG. 1 is a cross-sectional view showing the main part of the mold apparatus 10. The mold apparatus 10 is roughly composed of a fixed mold 20 which is one mold and a movable mold 40 which is the other mold. In the present embodiment, the fixed mold 20 is disposed on the right side and the movable mold 40 is disposed on the left side, and the movable mold 40 is moved toward and away from the fixed mold 20 in the horizontal direction.

  The fixed mold 20 and the movable mold 40 have mating surfaces 20A and 40A that are in close contact with each other. Due to the approach and separation of the movable mold 40, both the mating surfaces 20A and 40A take the positions of the joined state and the separated state. The movement of the movable mold 40 in the approaching and separating direction is performed by a known hydraulic drive device (not shown).

  A cavity 12 that is an annular (ring-shaped) space is formed on the mating surface 40A of the movable mold 40, and an insertion recess 81 that is a cylindrical space is formed at the center side position of the cavity 12. Has been. The other end of the gate 18, which is a cylindrical space, is opened on the mating surface 20 </ b> A of the fixed mold 20, and the gate 18 is positioned on the inner diameter side from the middle in the radial direction of the cavity 12. Further, on the mating surface 20 </ b> A of the fixed mold 20, the small-diameter shaft portion 64 protrudes toward the movable mold 40 at the center side position of the gate 18, and the small-diameter shaft portion 64 is fitted into the fitting recess 81 of the movable mold 40.

  The movable mold 40 is roughly divided into a second main body mold 42 in which a storage recess 41 that is a cylindrical space is formed, a cylindrical insert mold 70 that is inserted and disposed in the storage recess 41, and screwed to the insert mold 70. The holding member 80 and a pin 85 that pushes out the worm wheel 90 from the cavity 12.

  The cylindrical portion 82 of the holding member 80 is fitted into the fitting hole of the nested mold 70 and positioned in the radial direction, and the female screw 83 of the holding member 80 is screwed into the female screw 73 of the nested mold 70, so that the nested mold A holding member 80 is fixed to 70. A cavity 12 that is an annular space is formed in the nested mold 70, and convex portions 71 that form the gear 91 are formed at equal intervals in the circumferential direction on the inner periphery of the nested mold 70. A part of the holding member 80 protrudes into the cavity 12. The metal part 93 is fitted into the cylindrical part 82 that is a protruding part of the holding member 80 to position and hold the metal part 93 in the radial direction, and the metal part 93 is held in the axial direction by the core cylinder 60 and the insert mold 70. Thus, the metal part 93 is positioned and held in the axial direction. A fitting recess 81 that is a cylindrical space is formed on the end surface of the holding component 80 on the fixed mold 20 side.

  The fixed mold 20 is broadly divided into a first body mold 22, a valve probe 35 disposed on the inner periphery of the first body mold 22, and a sleeve body 30 as a valve body disposed on the inner periphery of the first body 22. A core cylinder 60 disposed on the inner periphery of the valve probe 35, a hot runner manifold 58 and a base mold 50 disposed on the opposite side of the movable body 40 with respect to the first body mold 22, and a first heater 55. And the second heater 56. These components are arranged in the order of the core cylinder 60, the valve probe 35, the sleeve body 30, and the first main body mold 22 in order from the center to the outer diameter direction when viewed from the position of the mating surface 20 </ b> A of the fixed mold 20. Has been placed. Similarly, at the position of the hot runner manifold 58, the core cylinder 60 and the hot runner manifold 58 are arranged in this order from the center. The first heater 55 has a columnar shape and is fitted in the cylindrical hole 65 of the core cylinder 60. The second heater 56 has a cylindrical shape and is embedded in the valve probe 35.

  The core cylinder 60 includes a first half member 60a and a second half member 60b, and the first half member 60a and the second half member 60b are screwed together. A recess is perforated on the end surface of the first half member 60a on the second half member 60b side, and a female screw 60c is formed in the recess. A convex portion is formed on the end surface of the second half member 60b on the first half member 60a side, and a screw 60d is formed on the convex portion. The first half member 60a and the second half member 60b are threadedly engaged with the female screw 60c until the end surfaces thereof are in close contact with each other.

  The core cylinder 60 is formed in a substantially cylindrical shape, and the above-described first heater 55 is fitted in the central cylindrical hole 65, and a step portion formed in the middle of the cylindrical hole 65 in the axial direction and the cylindrical hole 65. The first heater 55 is clamped in the axial direction by a circlip 66 attached to the other end of the first heater 55. The core cylinder 60 includes a flange portion 61 projecting in the outer diameter direction, a cylindrical large-diameter shaft portion 62, a tapered taper portion 63, and a cylindrical small-diameter shaft portion 64, which are movable from the base mold 50. It has in order toward 40. The core cylinder 60 is positioned in the axial direction by sandwiching the flange portion 61 of the core cylinder 60 between the base mold 50 and the hot runner manifold 58. The core cylinder 60 is positioned in the radial direction with respect to the hot runner manifold 58 by fitting the large diameter shaft portion 62 into the fitting hole of the hot runner manifold 58. The tapered portion 63 has a shape that gradually increases in diameter toward the movable mold 40, and the small-diameter shaft portion 64 is a cylindrical shape that extends in the axial direction and has a diameter that is smaller than the large-diameter shaft portion 62. The small diameter shaft portion 64 is loosely fitted in the fitting recess 81.

  The core cylinder 60 has a step portion extending in the radial direction between the taper portion 63 and the small diameter shaft portion 64. The step portion is an end surface that is a part of the mating surface 20 </ b> A of the fixed mold 20. An attachment recess 67 that is an annular space is formed in the stepped portion, and an annular sheet-like heat insulating material 68 is fixed to the attachment recess 67 with an adhesive. As the heat insulating material 68, a nonwoven fabric made of glass fiber is used. The heat insulating material 68 is provided at a position where the metal part 93 and the holding member 80 abut, and is not provided at a position where the resin part 92 is molded. Since the heat insulating material 68 has a lower thermal conductivity than the iron-based metal part 93 and the iron-based holding member 80, it is difficult for heat to escape from the tapered portion 63 to the metal part 93 and the holding member 80.

  The valve probe 35 is formed in a substantially cylindrical shape, and a flange portion 36 that is enlarged in the outer diameter direction is formed at one end of the valve probe 35 on the base 50 side. The valve probe 35 is axially positioned with respect to the first body mold 22 by sandwiching the flange portion 36 of the valve probe 35 between the step of the first body mold 22 and the hot runner manifold 58. Is done. By fitting the flange portion 36 of the valve probe 35 into the fitting hole of the first main body mold 22, the valve probe 35 is positioned in the radial direction with respect to the first main body mold 22.

  The valve probe 35 has a cylindrical hole 37 penetrating in the axial direction at a central position, and a tapered hole 38 that expands in the radial direction toward the movable side 40 at the other end. A predetermined gap is provided between the cylindrical hole 37 and the large-diameter shaft portion 62 to constitute the first supply passage 16B. A predetermined gap is provided between the taper hole 38 and the taper portion 63 to constitute the second supply passage 16A. The first supply passage 16B is a cylindrical space extending in the axial direction. The second supply passage 16A is a tapered space extending in the axial direction and in the outer diameter direction. One end of the second supply passage 16A is connected to the first supply passage 16B, and the other end of the second supply passage 16A is connected to the gate 18.

  A predetermined gap is provided between the tapered portion 63 and the inner periphery of the first main body mold 22 to constitute the gate 18. The gate 18 is a cylindrical space extending in the axial direction, and is disposed between the second supply passage 16 </ b> A and the cavity 12 in the axial direction. A sleeve body 30 is removably inserted into the gate 18.

  The sleeve body 30 as a valve body is disposed between the valve probe 35 and the first main body mold 22 so as to be movable in the axial direction. The sleeve body 30 has a flange portion 31 extending in the outer diameter direction at one end, an operating rod 33 is connected to the flange portion 31, and a cylinder device (not shown) is connected to the operating rod 33. As the sleeve 26 advances and retreats in the axial direction via the cylinder device and the operating rod 33, the gate 18 is opened and closed. The sleeve body 30 is formed in a substantially cylindrical shape, and the insertion portion 32 at the other end is formed as a thin-walled cylindrical shape. The insertion part 32 is detachably inserted into the gate 18 to open and close the gate 18.

  The hot runner manifold 58 is disposed in a state where the large-diameter shaft portion 62 of the core cylinder 60 is fitted, and the end surface on the first body die 22 side is joined to the end surface of the flange portion 36 of the valve probe 35. ing. The hot runner manifold 58 is formed with a molten resin supply passage 16D as indicated by a broken line in FIG. As shown in FIG. 2, the supply passage 16 </ b> D is formed as a single passage and is connected to a supply passage 16 </ b> C formed between the hot runner manifold 58 and the core cylinder 60. The supply passage 16C is formed as a cylindrical passage similarly to the first supply passage 16B described above, and one end of the first supply passage 16B is connected to the supply passage 16C.

  In the present embodiment, the second supply passage 16A, the first supply passage 16B, and the supply passage 16C have a circular cross section and communicate in the axial direction. And in this embodiment, the sleeve body 30 as a valve body is arrange | positioned by the outer peripheral side position of 16 A of 1st supply passages, the 1st supply passage 16B, and the supply passage 16C which were formed in circular cross section. Even if the sleeve body 30 is configured to move in the axial direction to open and close the gate 18, there is no particular problem in forming the sleeve body 30 with a large diameter. Accordingly, the gate 18 having a circular cross section can have a large diameter, and the product-shaped cavity 12 to which the molten resin is supplied from the gate 18 can also have a large diameter. It becomes possible to mold a resin product.

The first heater 55 is disposed in the cylindrical hole 65 of the core cylinder 60 as described above. The other end of the first heater 55 extends from the mounting recess 67 to the small-diameter shaft 64, and the first heater 55
Not only the large diameter shaft portion 62 but also the tapered portion 63 and the small diameter shaft portion 64 are positively heated. The second heater 56 is disposed so as to be embedded in the valve probe 35, and is disposed in a cylindrical shape at the outer peripheral portion position of the first supply passage 16B. The other end of the second heater 56 extends to the vicinity of the tapered hole 38 and actively heats not only the first supply passage 16B but also the second supply passage 16A. The molten resin in the first supply passage 16B and the second supply passage 16A is heated by the first heater 55 and the second heater 56 so that the molten state of the molten resin supplied to the cavity 12 is appropriately maintained. In the present embodiment, in particular, since the molten resin in the first supply passage 16B is heated from both the inner diameter side and the outer diameter side of the first supply passage 16B close to the cavity 12, heating is performed efficiently. be able to.

  In the present embodiment, the first heater 55 and the second heater 56 are disposed at positions that are in a positional relationship from the center of the annular outer periphery of the annular cavity 12 as seen in FIG. ing. This makes it possible to configure the mold apparatus 10 without relatively increasing the size, although it is a molding apparatus for a product having a relatively large diameter.

  Next, the injection molding operation of the mold apparatus 10 described above will be described with reference to FIGS. 1 and 3 to 6.

  FIG. 6 shows the mold closed state. With the movable mold 40 approaching the fixed mold 20 and being matched, and the sleeve body 30 is in a position moved to the movable mold 40 side, and the gate 18 is closed by the sleeve body 30. is there. In this state, the molten resin is not supplied from the second supply passage 16 </ b> A to the cavity 12 because the gate 18 is closed by the sleeve body 30.

  FIG. 7 shows an injection molding state in which the sleeve 18 is moved to the base mold 50 side from the state of FIG. In this state, the gate 18 is in an open state, and the molten resin in the second supply passage 16 </ b> A is supplied to the cavity 12 through the gate 18. At this time, since the gate 18 is connected to the entire circumferential surface of the annular cavity 12, the molten resin is supplied to the cavity 12 from the entire circumference of the annular cavity. For this reason, it is possible to prevent welds from occurring in the resin molded product.

  FIG. 1 shows a state in which the gate 18 is closed by moving the sleeve body 30 to the movable mold 40 side after the injection molding of the molten resin into the cavity 12 shown in FIG. 7 is completed. In this state, the annular cavity 12 is filled with the molten resin, and the supply of the molten resin from the gate 18 to the cavity 12 is stopped, and is molded according to the shape of the cavity 12 by naturally cooling it. The worm wheel 90 becomes.

  3 shows a state in which the worm wheel 90 is formed in the cavity 12 through the natural cooling state shown in FIG. In this state, the mating surfaces 20A and 40A of the mold 20 and the movable mold 40 are opened. In this state, the worm wheel 90 is placed in the cavity 12 of the movable mold 40.

  FIG. 4 shows a state in which the pin 85 is moved to the fixed mold 20 side and the worm wheel 90 is taken out from a position where the cavity 12 of the movable mold 40 is formed in the mold opened state shown in FIG.

  4, the pin 85 is moved to the opposite side of the fixed mold 20 from the opened state as shown in FIG. 5 so that the pin 85 does not protrude from the bottom surface of the cavity 12, and is in contact with the nested mold 70. The metal part 93 is fitted in the holding member 80 until the metal part 93 is positioned and held in the radial direction by the holding member 80 and is held in the axial direction by the insert mold 70.

  From the state in which the metal part 93 is placed in the cavity 12 shown in FIG. 5, the movable die 40 is moved in the direction approaching the fixed die 20 as shown in FIG. 6, and the mating surface 20A and the mating surface 40A are brought into close contact with each other. Let One end of the metal part 93 abuts against the heat insulating material 68, and the metal part 93 is sandwiched between the insert mold 70 and the heat insulating material 68 in the axial direction. Since the metal part 93 and the holding member 80 are in contact with the heat insulating material 68 and are not in direct contact with the core cylinder 60, the heat of the tapered portion 63 heated by the first heater 55 escapes to the metal part 93 and the holding member 80. Can be prevented, and molding defects due to a decrease in molten resin temperature can be eliminated.

  By repeating the operations shown in FIGS. 1 and 3 to 7, a relatively large-diameter annular worm wheel 90 can be produced in large quantities by injection molding.

  According to the above-described embodiment, the arrangement position of the sleeve body 30 as the valve body is set so that the second passage 16A, the first supply passage 16B, and the supply passage having a circular cross section for supplying the molten resin to the cavity 12 through the gate 18 are provided. By setting the position to the outer peripheral side of 16C, the cylindrical sleeve body 30 for opening and closing the gate 18 can be formed in a large diameter. As a result, the annular cavity 12 to which the circular gate 18 is connected to the entire circumference can also have a large diameter, and the large diameter worm wheel 90 can be injection molded.

  The present invention is not limited to these embodiments, and can of course be implemented in various modes without departing from the gist of the present invention.

  In the embodiment described above, the second main body mold 42, the nesting mold 70, and the holding member 80 are configured as separate members. As another embodiment, the second main body mold 42, the nesting mold 70, and the holding member 80 may be configured as an integral member.

  10: ring valve gate type mold apparatus, 12: cavity, 16A: second supply passage, 16B: first supply passage, 18: gate, 20: fixed mold, 20A: mating surface, 22: first body mold (first 1 type), 30: sleeve body, 35: valve probe, 37: cylindrical hole, 38: taper hole, 40: movable type, 40A: mating surface, 42: second body type (second type), 55: first Heater: 56: second heater, 60: core cylinder, 62: large-diameter shaft, 63: taper, 64: small-diameter shaft, 67: mounting recess (dent), 68: heat insulating material, 70: nested type (first) 2 type), 80: holding member, 82: cylindrical part, 90: worm wheel (resin product), 91: gear, 92: resin part, 93: metal part

Claims (1)

A core cylinder;
A valve probe disposed on the outer periphery of the core cylinder and forming a first supply passage extending in the axial direction with the core cylinder and a second supply passage extending in the axial direction and in the outer diameter direction;
A first mold that is disposed on an outer periphery of the core cylinder and forms a gate that is a cylindrical space extending in the axial direction with the core cylinder;
A sleeve body that moves in the axial direction to be inserted into and removed from the gate;
A second mold that is close to and away from the first mold in the axial direction and forms a cavity that is an annular space with the first mold;
A holding member that is fixed to the second mold so that a part of the cavity protrudes into the cavity, and holds and holds an annular metal part in the axial direction and the radial direction with the second mold;
The annular metal part is positioned and held by the holding member and the second mold, and the first mold and the second mold are brought into contact with each other, and the first supply path, the second supply path, and the gate are sequentially transferred to the cavity. A mold apparatus configured to mold a resin product having the metal part on the inner peripheral side and the resin part on the outer peripheral side with the cavity by flowing molten resin,
Forming an annular recess in the end surface of the core cylinder on the holding member side;
An annular heat insulating material is placed in the annular dent,
A mold apparatus, wherein the heat insulating material is disposed at a position where the metal part contacts when the first mold and the second mold are brought into contact with each other.

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