JP5860263B2 - Blow molding die head, blow molding apparatus, uneven thickness parison formation method, and irregularly shaped product manufacturing method - Google Patents

Description

  The present invention relates to a blow molding die head, a blow molding apparatus, a method for forming an uneven parison, and a method for manufacturing a deformed product. More specifically, the present invention relates to a blow molding die head capable of easily forming a deformed product, a blow molding device including the blow molding die head, and forming an uneven thickness parison using the blow molding die head. The present invention relates to a method and a method for producing a deformed product.

  A blow molding method is known as a molding method capable of efficiently producing a hollow resin molded product. Normally, in blow molding, a thermoplastic resin tubular melt (parison) discharged from a die head is sandwiched between a pair of molds, and air is blown into the parison to mold the parison into a mold cavity shape and cooling. A method of solidifying into a molded product is adopted. Conventionally, various techniques for obtaining a molded product having a uniform thickness by such a blow molding method have been proposed. On the other hand, depending on the purpose of the molded product obtained by the blow molding method and the method of secondary processing, a molded product having a partially or partially uneven thickness may be required. For example, a molded product (primary molded product) that is used for ducts, pipes, etc. of automobile parts and is subjected to bending processing has a portion corresponding to the outer diameter of the bending portion in order to obtain thickness uniformity after bending processing. Thickness is required.

  Conventionally, the uneven thickness adjustment for obtaining such an uneven thickness molded product is formed by the die 20 and the core 30 by horizontally moving the die 20 with a hydraulic cylinder or the like, as shown in the schematic sectional view of FIG. This is done by making the thickness in the circumferential direction of the nozzle port 4 (parison discharge portion) uneven (for example, Patent Document 1). However, the mechanism for moving the dice 20 horizontally becomes large, and movement control is difficult, and there is a problem that the apparatus becomes expensive.

Japanese Patent Laid-Open No. 5-92474

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a blow molding die head capable of easily forming a deformed product (unevenly formed product). is there.

A die head for blow molding according to the present invention includes a die head main body, an annular die located at an end of the die head main body, and a core inserted through the die head main body. The die and the core form an annular parison discharge nozzle opening, and the die head main body has a support portion for supporting the die on the inner peripheral surface of the die. The die head is supported by the support portion on the inner peripheral surface of the die so as to be reciprocally movable and tiltable relative to the parison discharge direction of the die head body, and the die is discharged from the die head body. Reciprocating relative to the direction, the circumferential thickness of the nozzle opening can be adjusted, and the die is inclined with respect to the parison discharge direction of the die head body, The circumferential thickness of the nozzle opening may unevenly adjusted.
In a preferred embodiment, the die is further supported by a plurality of rods that can reciprocate in parallel to the parison discharge direction, and the rods move independently to swing the die. By fixing the die at a predetermined position, the die is fixed while being inclined with respect to the parison discharge direction of the die head body.
In a preferred embodiment, the support portion is a spherical bearing attached to the outer peripheral surface of the die head body.
In a preferred embodiment, the support portion is a rubber ring attached to the outer peripheral surface of the die head body.
According to another aspect of the present invention, an apparatus for blow molding is provided. This blow molding apparatus includes the blow molding die head.
According to another aspect of the present invention, a method for forming an uneven parison is provided. This method of forming the uneven parison includes controlling the wall thickness of the parison by using a blow molding die head and inclining the die.
According to another aspect of the present invention, a method for producing a deformed product is provided. The method for manufacturing the irregularly shaped product includes controlling the wall thickness of the parison by using a blow molding die head and inclining the die.

  ADVANTAGE OF THE INVENTION According to this invention, the die head for blow molding which can shape | mold an irregularly shaped product (unbalanced molded product) simply can be provided.

It is a schematic sectional drawing of the die head for blow molding by preferable embodiment of this invention. It is a schematic sectional drawing explaining the state where the dice | dies are not inclined in the die head for blow molding in this invention. It is a schematic sectional drawing explaining the state which the dice inclines in the die head for blow molding in the present invention. It is a schematic sectional drawing explaining the state which the dice inclines in the die head for blow molding in the present invention. It is a schematic sectional drawing of the conventional die head for blow molding.

  FIG. 1 is a schematic cross-sectional view of a blow molding die head according to a preferred embodiment of the present invention. The blow molding die head includes a cylindrical die head main body 10, an annular die 20 positioned at the end of the die head main body 10, and the die head main body 10. The tip protrudes from the die head main body 10. The core 30 is provided.

  A hollow mandrel 40 is nested in the die head main body 10, and an annular resin path 1 is formed between the inner peripheral surface of the die head main body 10 and the outer peripheral surface of the hollow mandrel 40. Preferably, the resin path 1 is formed to have a uniform thickness.

  The center (axial core) of the die head main body 10 and the center (axial core) of the core 30 are provided on the same line. The core 30 is connected to one end portion of a core shaft 41 that passes through the hollow mandrel 40, and the other end portion of the core shaft 41 is connected to an end portion opposite to the opening portion of the die head body 10. An annular resin path 2 is formed between the inner peripheral surface of the die head body 10 and the outer peripheral surface of the core 30. Preferably, the resin path 2 is formed to have a uniform thickness. The resin path 2 communicates with the resin path 1.

  The die 20 is positioned so as to form an annular resin path 3 between the inner peripheral surface of the die 20 and the outer peripheral surface of the core 30 at the opening end of the die head main body 10. In the opening of the die 20, the die 20 and the core 30 form an annular parison discharge nozzle port 4. The resin path 3 communicates with the resin path 2 and the nozzle port 4. That is, in the blow molding die head of the present invention, the resin (heated and melted resin) charged from an extruder (not shown) connected to the blow molding die head is used as the resin path 1 and the resin path. 2 and the resin path 3 pass in this order, and the parison discharges from the nozzle port 4.

  The die head main body 10 has a support portion 11 for supporting the die 20 on the inner peripheral surface of the die 20. The die 20 is supported by the support portion 11 on the inner peripheral surface of the die 20 so that the die 20 can reciprocate and tilt relative to the parison discharge direction of the die head body 10.

  The die 20 has a tapered surface 21 on the inner peripheral surface near the opening. The taper angle of the taper surface 21 can be set according to the shape of the core 30 (described later).

  The die 20 can be reciprocated relative to the parison discharge direction of the die head body 10 to adjust the circumferential thickness of the nozzle port 4 formed by the die 20 and the core 30. The core 30 has a tapered surface 31 on the outer peripheral surface at the tip in the parison discharge direction. Since the core 30 has the tapered surface 31, the die 20 can be reciprocated relative to the parison discharge direction of the die head body 10 to adjust the circumferential thickness of the nozzle port 4. Thus, by adjusting the thickness of the nozzle port 4 in the circumferential direction, the thickness of the parison to be discharged can be adjusted. The circumferential thickness of the nozzle opening 4 may be adjusted by reciprocating the die 20, or by reciprocating the core 30, or a combination thereof. As shown in FIG. 1, the tapered surface 31 of the core 30 may form a shape that expands toward the outer periphery of the core 30 (die purge), or may form a shape that narrows toward the center of the core 30. (Compurge). The shape of the core 30 can be selected according to the desired size, shape, etc. of the molded product. When the core 30 has a shape that expands toward the outer periphery (die purge), the tapered surface 21 of the die 20 forms an opening that extends toward the outer periphery of the die 20 as shown in FIG. In the case of a shape that narrows toward the center of the core 30 (compurge), the tapered surface 21 of the die 20 forms an opening that narrows toward the center of the die 20.

  The dice 20 can be inclined with respect to the parison discharge direction of the dice head body 10. FIG. 2 is a schematic view showing a state where the die 20 is not inclined, and FIGS. 3 and 4 are schematic views showing a state where the die 20 is inclined. As shown in FIG. 2, when the die 20 is not inclined, the center (axial core) of the die 20 and the center (axial core) of the die head main body 10 are provided on the same line, and the parison has a uniform thickness. It is discharged to become. The thickness of the parison can be adjusted by the reciprocating movement of the die 20 and / or the core 30 as described above. In the present invention, the die 20 can be tilted as shown in FIGS. 3 and 4 from a state where it is not tilted (FIG. 2). When the die 20 is tilted, the circumferential thickness of the nozzle opening 4 becomes non-uniform, and the parison is discharged in an uneven thickness state. Even when the die 20 is inclined, the average value of the wall thickness of the parison can be adjusted by the reciprocating movement of the die 20 and / or the core 30 as described above. The thickness adjustment can be performed by adjusting the inclination angle of the die 20.

  The die 20 can be tilted by any suitable means. In one embodiment, as shown in FIGS. 1, 3 and 4, the die 20 can be inclined by adopting a spherical bearing attached to the outer peripheral surface of the die head body 10 as the support portion 11. . In this case, the die 20 can swing in contact with the convex surface of the spherical bearing, and is inclined with respect to the parison discharge direction of the die head body 10. In another embodiment, a rubber ring attached to the outer peripheral surface of the die head main body 10 is employed as the support portion 11. In this case, since the rubber ring can be deformed according to the swing of the die 10, the die 20 can be inclined. The support part 11 is not limited to these, and any appropriate support part can be selected as long as it can support the die 20 and be inclined.

  The die 20 can be further supported by a plurality of rods 50 that can reciprocate parallel to the parison discharge direction. By reciprocating the rod 50, the die 20 can be reciprocated relatively to the parison discharge direction of the dice head body 10. Furthermore, as shown in FIGS. 3 and 4, the dice 20 can be swung and inclined by moving the rods 50 independently. Preferably, the rod 50 is connected to the die 20 via a universal joint 51. The number of rods 50 is preferably 2-8, more preferably 3-4. The rods 50 are preferably provided at equal intervals. This is because the inclination of the die 20 can be accurately controlled. The rod 50 can be controlled to reciprocate by being connected to the servo actuator 70 via the output converter 60, for example.

  When discharging the parison, the dice 20 is fixed at an incline at a predetermined position. Any appropriate method can be adopted as a method of fixing the die 20. In one embodiment, as shown in FIGS. 3 and 4, the die 20 can be fixed by moving the rod 50 as described above and then fixing it. It is also possible to change the inclination angle and / or direction of the dice 20 while the parison is being discharged. According to the present invention, since the uneven thickness adjustment of the parison can be easily performed by inclining the dice 20, it is possible to manufacture a deformed product having a complicated shape at a low cost.

  The blow molding apparatus of the present invention includes the above blow molding die head. The blow molding apparatus of the present invention may further include a known mechanism such as a hopper, an extruder, a heater, an air blowing device, and a known mold in addition to the blow molding die head.

  If the above-described die head for blow molding is used, an uneven parison can be formed. Specifically, the uneven wall parison can be formed by tilting the die 20 of the blow molding die head and controlling the thickness (uneven wall thickness) of the parison. In the uneven thickness parison formation method, known conditions can be adopted for other conditions such as selection of resin used, extrusion, and heating. In one embodiment, the blow-molding die head is placed vertically to form an uneven parison. In this case, the parison is sandwiched between the molds in the uneven thickness state, blown with air, and cooled and solidified to form a deformed shaped product in the uneven thickness state. According to the blow molding die head or blow molding device of the present invention, it is easy to change the inclination angle and / or direction of the die 20 while the parison is being discharged. By forming a meat part, a complex shaped product can be produced. For example, after obtaining a primary molded product in which a plurality of thick portions are formed by blow molding, a thick-formed portion can be bent to obtain a deformed product having a plurality of bent portions. A deformed product in which a plurality of bent portions are bent in different directions can be easily obtained.

  In another embodiment, the blow molding die head is placed sideways to form an uneven parison. In this case, the thickness of the uneven parison immediately after discharge changes due to gravity before being sandwiched between the molds. In this embodiment, a thick-wall parison is formed with a thick upper part, and then sandwiched in a mold in a state where the thickness is uniform by gravity, blown with air, cooled and solidified, and then a molded product with a uniform thickness Can be molded. According to the present invention, since the uneven thickness of the uneven parison can be easily adjusted, the wall thickness is uniform without the restriction of the height of the building where the blow molding die head is placed horizontally and the apparatus is installed. A long molded product can also be easily obtained.

1, 2, 3 Resin path 4 Nozzle port 10 Die head main body 11 Support part 20 Dice 21, 31 Tapered surface 30 Core 40 Hollow mandrel 41 Core shaft 50 Rod 51 Universal joint 60 Output converter 70 Servo actuator

Claims (7)

A die head main body, an annular die positioned at an end of the die head main body, and a core inserted through the die head main body, and the die and the core form an annular shape at the opening of the die. Nozzle opening for parison discharge is formed,
The die head main body has a support portion for supporting the die on the inner peripheral surface of the die,
The die is supported by the support portion on the inner peripheral surface of the die so that the die can reciprocate and tilt relative to the parison discharge direction of the die head body,
The die can be moved reciprocally relative to the parison discharge direction of the die head body to adjust the circumferential thickness of the nozzle opening, and the die can be adjusted relative to the parison discharge direction of the die head body. The thickness of the nozzle mouth in the circumferential direction can be adjusted unevenly,
Die head for blow molding. The die is further supported by a plurality of rods that can reciprocate parallel to the parison discharge direction,
The rods are independently moved to swing the die, and the rod is fixed at a predetermined position, and the die is fixed to be inclined with respect to the parison discharge direction of the die head body. The blow molding die head according to claim 1.   The blow molding die head according to claim 1, wherein the support portion is a spherical bearing attached to an outer peripheral surface of the die head main body.   The blow molding die head according to claim 1, wherein the support portion is a rubber ring attached to an outer peripheral surface of the die head main body.   A blow molding device comprising the blow molding die head according to claim 1.   A method for forming an uneven parison, comprising controlling the thickness of the parison by using the blow molding die head according to any one of claims 1 to 4 and inclining the die.   A method for producing an irregularly shaped product, comprising controlling the thickness of a parison by using the blow molding die head according to claim 1 and tilting the die.

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