Stretching rod sliding mechanism, intermediate mold, and mold assembly

Abstract

To more stabilize a movement of a stretching rod that slides through a through hole formed in a blowing core.SOLUTION: A stretching rod sliding mechanism 100 has: a stretching rod 343 for outputting high-pressure air for stretching a preform being an intermediate molded product in blow molding from a tip portion 351; a stretching plate 342 which is joined with the stretching rod 343 and moves in an axial direction of the stretching rod 343; a blowing core 341 formed with a through hole 61 for guiding the stretching rod 343 that moves in the axial direction as the stretching plate 342 moves; and a guiding rod 344 that penetrates the stretching plate 342 in the axial direction of the stretching rod 343, and guides the stretching plate 342 that moves in the axial direction of the stretching rod 343.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an extension bar sliding mechanism, an intermediate mold, and a mold device.

Background Art

[0002] In injection blow molding, which is a molding method that performs injection molding (injection molding) and blow molding (blow molding) in two steps, a preform, which is an intermediate molded product, is molded by injection molding, and a product such as a container is molded by blowing air into the preform and expanding it. In injection blow molding, in the blow molding step, an extension bar having one end joined to an extension plate and the other end passing through a through hole of a blow core slides through the through hole of the blow core as the extension plate moves, and the tip portion enters the preform to blow air (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The through hole of the blow core guides the extension bar that operates in the axial direction. However, if some force is applied to the extension plate and the operation becomes unstable, the operation of the extension bar joined to the extension plate also becomes unstable, which may cause "core deviation" such as uneven wall thickness and gate shift in the molded product. Furthermore, friction may occur between the blow core and the extension bar, generating abrasive powder, or die biting may occur. Therefore, it is desirable that the operation of the extension plate and the operation of the extension bar be more stable. An object of the present invention is to further stabilize the operation of the extension bar that slides through the through hole formed in the blow core.

Means for Solving the Problems

[0005] The present invention completed for such an object is a stretching rod that outputs a fluid for stretching an intermediate molded product by blow molding from a tip portion, a stretching plate joined to the stretching rod and moving in the axial direction of the stretching rod, and a blow core portion in which a through hole for guiding the stretching rod that moves in the axial direction as the stretching plate moves is formed, and a guiding member that penetrates the stretching plate in the axial direction of the stretching rod and guides the stretching plate that moves in the axial direction of the stretching rod, and is a stretching rod sliding mechanism characterized by having the same. Here, the guiding member may be a columnar member with both ends fixed. Further, a predetermined first gap is formed between the stretching rod and the blow core portion in the through hole, a predetermined second gap is formed between the guiding member and the stretching plate at a portion where the guiding member penetrates the stretching plate, and a third gap serving as play may be formed at a joint portion between the stretching rod and the stretching plate. Also, each of the first gap and the second gap may be made smaller than the third gap. The present invention is also an intermediate mold having a stretching rod sliding mechanism, wherein the stretching rod sliding mechanism is a stretching rod that outputs a fluid for stretching an intermediate molded product by blow molding from a tip portion, a stretching plate joined to the stretching rod and moving in the axial direction of the stretching rod, a blow core portion in which a through hole for guiding the stretching rod that moves in the axial direction as the stretching plate moves is formed, and a guiding member that penetrates the stretching plate in the axial direction of the stretching rod and guides the stretching plate that moves in the axial direction of the stretching rod, and is an intermediate mold characterized by having the same. The present invention is also a mold device including a fixed-side mold, an intermediate mold having a stretching rod sliding mechanism, and a movable-side mold, wherein the stretching rod sliding mechanism of the intermediate mold is a stretching rod that outputs a fluid for stretching an intermediate molded product by blow molding from a tip portion, a stretching plate joined to the stretching rod and moving in the axial direction of the stretching rod, a blow core portion in which a through hole for guiding the stretching rod that moves in the axial direction as the stretching plate moves is formed, and a guiding member that penetrates the stretching plate in the axial direction of the stretching rod and guides the stretching plate that moves in the axial direction of the stretching rod, and is a mold device characterized by having the same.

Effect of the Invention

[0006] According to the present invention, the operation of the stretching rod that slides through the through-hole formed in the blowing core can be further stabilized.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <Configuration of Mold Device> FIG. 1 is a view showing an example of a partial configuration of a mold device 10 including an intermediate mold 12 to which the stretching rod sliding mechanism 100 according to the present embodiment is applied. FIG. 2 is a view showing an example of a partial configuration of the stretching rod sliding mechanism 100. Note that FIG. 2 is an enlarged view of a region 500 surrounded by a broken line in FIG. 1 described above.

[0009] The mold device 10 shown in FIG. 1 is a mold device that constitutes an injection molding machine for performing injection blow molding. Injection blow molding refers to a molding method that performs injection molding (hereinafter referred to as "injection molding") and blow molding (hereinafter referred to as "blowing molding") in two steps. In injection blow molding, an intermediate molded product, a preform (not shown), is molded by injection molding, and a high-pressure air is blown into the preform and expanded by blow molding to mold a container or the like, which is the final molded product.

[0010] In this embodiment, as a method of blowing high-pressure air into the inside of a preform in injection blow molding, a stretching rod 343 (described later) capable of outputting high-pressure air is made to project into the preform. The direction in which the stretching rod 343 projects into the preform is the direction from the left side to the right side of the drawing in FIG. 1, the axial direction of the stretching rod 343, and also the opening / closing direction of the mold device. Hereinafter, the direction in which the stretching rod 343 projects into the preform (the left-right direction of the drawing in FIG. 1) is referred to as the "axial direction" or the "opening / closing direction". Also, the left side of the drawing in FIG. 1 is referred to as the "first side in the opening / closing direction", and the right side of the drawing in FIG. 1 is referred to as the "second side in the opening / closing direction".

[0011] The mold device 10 is configured to include a fixed-side mold 11, an intermediate mold 12, and a movable-side mold 13. The mold device 10 performs injection molding by closing the mold between the intermediate mold 12 and the fixed-side mold 11. Also, the mold device 10 performs blow molding by closing the mold between the intermediate mold 12 and the movable-side mold 13.

[0012] The fixed-side mold 11 constituting the mold device 10 has a fixed platen 21, a fixed mold 22, and a drive device 23. The fixed platen 21 is a metal member that supports the fixed mold 22. The fixed mold 22 is a mold for performing injection molding and has an injection cavity 221. The drive device 23 is a device that moves the intermediate mold 12 in the opening / closing direction with respect to the fixed platen 21. On the second side in the opening / closing direction with respect to the fixed platen 21, an injection device (not shown) for injecting the molten resin that becomes the material of the preform to be injection molded is installed.

[0013] The intermediate mold 12 that constitutes the mold device 10 is a so-called rotary mold disposed between the fixed-side mold 11 and the movable-side mold 13. The intermediate mold 12 performs mold closing and mold opening at positions facing each of the fixed-side mold 11 and the movable-side mold 13. The intermediate mold 12 rotates about an axis orthogonal to the opening and closing direction, and has a rotating frame 31 that rotates around the outer side of the shaft body 38 in the circumferential direction of the shaft body 38, and a support frame 32 that supports the shaft body 38. The intermediate mold 12 also has an injection core 331 that serves as a core in injection molding, an injection core frame 33 that supports the injection core 331, a blowing core 341 that serves as a core in blow molding, and a blowing core frame 34 that supports the blowing core 341.

[0014] Further, the intermediate mold 12 has an extension plate 342 that moves in the opening and closing direction, an extension rod 343 that moves in the opening and closing direction as the extension plate 342 moves, and a guide rod 344 that guides the movement of the extension plate 342. The intermediate mold 12 also has a gripping mechanism 35 that rotates together with the rotating frame 31, a sliding frame 36, and a guide bar 37. The intermediate mold 12 also has a shaft body 38 having a central axis in a direction orthogonal to the axial direction of the extension rod 343, and a drive device 39 that rotates the rotating frame 31.

[0015] The blowing core frame 34 that constitutes the intermediate mold 12 is a metal member that supports the blowing core 341 by welding or the like as a part of the blowing core portion. Inside the blowing core frame 34, an extension plate 342, an extension rod 343, and a guide rod 344 are disposed. The blowing core frame 34, the blowing core 341, the extension plate 342, the extension rod 343, and the guide rod 344 function as elements that constitute the extension rod sliding mechanism 100 according to the present embodiment.

[0016] The injection core 341 that constitutes the intermediate mold 12 is a mold member that serves as a core in injection molding as a part of the injection core portion. When the mold device 10 closes the mold, it adheres to the injection cavity 421 of the movable split mold 42 that can open and close in a direction orthogonal to the opening and closing direction of the mold device 10, forming a space for injection molding. Also, when the mold device 10 opens the mold, the injection core 341 separates from the injection cavity 421 of the movable split mold 42. Note that FIG. 1 shows the state where the mold device 10 has opened the mold. For this reason, the injection core 341 is separated from the injection cavity 421, and the movable split mold 42 has also been opened.

[0017] The extension plate 342 that constitutes the intermediate mold 12 is a metal plate material installed inside the injection core frame 34 so as to be movable in the opening and closing direction (axial direction of the extension rod 343). The first-side end 352 of the extension rod 343 in the opening and closing direction (axial direction) is joined to the extension plate 342. For this reason, when the extension plate 342 moves in the opening and closing direction (axial direction), the extension rod 343 moves in the opening and closing direction (axial direction of the extension rod 343) along with it. Since the end 352 of each of the plurality of extension rods 343 is joined to the extension plate 342, by moving the extension plate 342 in the opening and closing direction (axial direction of the extension rod 343), the plurality of extension rods 343 can be moved in the opening and closing direction (axial direction) simultaneously. The extension plate 342 operates by using a drive device (not shown) composed of a pneumatic cylinder device or the like as a drive source and moves in the opening and closing direction (axial direction of the extension rod 343).

[0018] The extension rod 343 that constitutes the intermediate mold 12 is a metal member capable of outputting high-pressure air for stretching the preform by blow molding from the tip portion 351. As shown in FIG. 2, one end portion 352 of the extension rod 343 on the side opposite to the tip portion 351 is joined to the extension plate 342. For this reason, when the extension plate 342 moves toward the second side in the opening and closing direction (axial direction of the extension rod 343), the extension rod 343 moves together with it toward the second side in the opening and closing direction (axial direction), and the tip portion 351 protrudes into the preform. A part of the tip side (the second side in the opening and closing direction (axial direction)) of the extension rod 343 including the tip portion 351 slidably penetrates through a through hole 61 formed in the blow core 341 and the blow core frame 34 and extending in the opening and closing direction (axial direction of the extension rod 343).

[0019] Here, a method of joining the extension rod 343 to the extension plate 342 will be described. As shown in FIG. 2, a through hole 62 including a small-diameter portion 354, a medium-diameter portion 355, and a large-diameter portion 356 is formed in the extension plate 342 stepwise from the second side toward the first side in the opening and closing direction (axial direction of the extension rod 343). On the other hand, the diameter of the main body portion 350 of the extension rod 343 is smaller than the diameter of the small-diameter portion 354. Further, the end portion 352 of the extension rod 343 has a flange shape. For this reason, the diameter of the flange portion of the end portion 352 is larger than the diameter of the small-diameter portion 354 but smaller than the diameters of the medium-diameter portion 355 and the large-diameter portion 356, respectively.

[0020] When the extension rod 343 is penetrated through the through hole 62 from the first side toward the second side in the opening and closing direction (axial direction of the extension rod 343), the flange portion of the end portion 352 cannot penetrate through the small-diameter portion 354 and stays in the medium-diameter portion 355. At this time, since the extension rod 343 becomes free on the first side in the opening and closing direction (axial direction), a metal block member 353 is filled in the space formed in the large-diameter portion 356. Thereby, the extension rod 343 is fixed in the opening and closing direction (axial direction). In this way, the extension rod 343 is joined to the extension plate 342.

[0021] The guide bar 344 that constitutes the intermediate mold 12 is a columnar metal member with both ends fixed in a state of passing through the through hole 63 formed in the extension plate 342 in the opening and closing direction (axial direction of the extension bar 343), as shown in FIG. 2. Specifically, as shown in FIG. 1, the end on the first side in the opening and closing direction (axial direction) of the guide bar 344 is fixed to the injection core frame 33, and the end on the second side in the opening and closing direction (axial direction) is fixed to the blowing core frame 34. The guide bar 344 functions as a guiding member that guides the extension plate 342 that moves in the opening and closing direction (axial direction of the extension bar 343).

[0022] The method of fixing both ends of the guide bar 344 is not particularly limited. As long as the guide bar 344 can be firmly fixed so as not to rattle, for example, it may be fixed using bolts or by welding. In this embodiment, both ends of the guide bar 344 are fixed to the injection core frame 33 and the blowing core frame 34 using bolts 361 that penetrate the guide bar 344 in the longitudinal direction (opening and closing direction) (see FIG. 2) (see FIG. 1). Specifically, although not shown, the end of the guide bar 344 on the first side in the opening and closing direction is fixed to the injection core frame 33 by a combination of a male screw formed at the end on the first side in the opening and closing direction of the bolt 361 and a female screw formed on the surface on the second side in the opening and closing direction of the injection core frame 33.

[0023] The gripping mechanism 35 that constitutes the intermediate mold 12 is a mechanism that grips the outer peripheries of the mouths of the preform and the final molded product. The sliding frame 36 that constitutes the intermediate mold 12 is a member that is slidably attached in the axial direction of the guide bar 37 and supports the gripping mechanism 35. When the sliding frame 36 slides on the guide bar 37, the gripping mechanism 35 moves together with it. The guide bar 37 that constitutes the intermediate mold 12 is a columnar member with one end fixed to the rotating frame 31, and the sliding frame 36 is slidably attached to the other end side. The guide bar 37 guides the sliding of the sliding frame 36.

[0024] The shaft body 38 that constitutes the intermediate mold 12 is a cylindrical metal member joined to the support frame 32, the injection core frame 33, and the blowing core frame 34. The drive device 39 that constitutes the intermediate mold 12 is a device that serves as a drive source for rotating the rotating frame 31, and is composed of, for example, a motor or the like. When the rotating frame 31 rotates, the guide bar 37, the sliding frame 36, and the gripping mechanism 35 rotate together, and alternately move between the position where injection molding is performed and the position where blow molding is performed.

[0025] The movable mold 13 that constitutes the mold device 10 has a movable platen 41, a movable split mold 42, and a drive device 43. The movable platen 41 is a metal member that supports the movable split mold 42. On the second side in the opening and closing direction with respect to the movable platen 41, a mold clamping device (not shown) for closing and opening the mold of the mold device 10 is installed. The movable split mold 42 is a split mold as a mold for performing blow molding, and has a blow cavity 421. The drive device 43 is a device that serves as a drive source for opening and closing the movable split mold 42 in the opening and closing direction.

[0026] The mold device 10 forms a final molded product such as a container by stretching the preform by protruding the stretching rod 343 into the preform and blowing high-pressure air as blow molding for the preformed product formed by injection molding. At this time, when the stretching rod 343 is protruded into the preform, the above-described stretching rod sliding mechanism 100 functions. In addition, an air flow path, an air output hole, or the like (not shown) for supplying high-pressure air used for blow molding is formed in the blow core 341, the stretching rod 343, or between them.

[0027] <The gap formed in the stretching rod sliding mechanism> Figures 3(A) to (C) are diagrams showing the positions of the gaps formed in the extension bar sliding mechanism 100. Figure 3(A) is an enlarged view of the region 501 surrounded by the broken line in FIG. 2 described above, and shows the position of the first gap 51 formed between the extension bar 343, the injection core 341, and the injection core frame 34. Figure 3(B) is an enlarged view of the region 502 surrounded by the broken line in FIG. 2 described above, and shows the position of the second gap 52 formed between the induction bar 344 and the extension plate 342. Figure 3(C) is an enlarged view of the region 503 surrounded by the broken line in FIG. 2 described above, and shows the position of the third gap 53 formed between the extension bar 343 and the extension plate 342.

[0028] As shown in FIG. 3(A), a first gap 51 is formed between the extension bar 343, the injection core 341, and the injection core frame 34, and the first gap 51 enables the extension bar 343 to slide in the through hole 61. The structure for forming the first gap 51 is designed such that the size of the first gap 51 falls within a predetermined range. Specifically, the diameter of the main body portion 350 of the extension bar 343 is designed to be slightly smaller than the diameter of the through hole 61.

[0029] Also, as shown in FIG. 3(B), a second gap 52 is formed between the induction bar 344 and the extension plate 342, and the second gap 52 enables the extension plate 342 to slide with respect to the induction bar 344. The structure for forming the second gap 52 is designed such that the size of the second gap 52 falls within a predetermined range. Specifically, the diameter of the induction bar 344 is designed to be slightly smaller than the diameter of the through hole 63 formed in the extension plate 342.

[0030] Also, as shown in FIG. 3(C), a third gap 53 is formed between the extension rod 343 and the extension plate 342, and the third gap 53 functions as a play of the extension rod 343 with respect to the extension plate 342. The structure for forming the third gap 53 is designed such that the size of the third gap 53 falls within a predetermined range. Specifically, the diameter of the main body portion 350 of the extension rod 343 is designed to be slightly smaller than the diameter of the small-diameter portion 354 of the through-hole 62 formed in the extension plate 342.

[0031] The extension rod sliding mechanism 100 according to the present embodiment is designed in consideration of the relationship between the structure for forming the first gap 51, the structure for forming the second gap 52, and the structure for forming the third gap 53. Specifically, each of the first gap 51 and the second gap 52 is designed to be smaller than the third gap 53. That is, the difference between the diameter of the main body portion 350 of the extension rod 343 and the diameter of the through-hole 61 is designed to be smaller than the difference between the diameter of the main body portion 350 of the extension rod 343 and the diameter of the small-diameter portion 354 of the through-hole 62. That is, the diameter of the through-hole 61 is designed to be smaller than the diameter of the small-diameter portion 354 of the through-hole 62. Also, the difference between the diameter of the guide rod 344 and the diameter of the through-hole 63 is designed to be smaller than the difference between the diameter of the main body portion 350 of the extension rod 343 and the diameter of the small-diameter portion 354 of the through-hole 62.

[0032] In the configuration where each of the first gap 51 and the second gap 52 is smaller than the third gap 53, the relationship between the structure for forming the first gap 51 and the structure for forming the second gap 52 is a relationship of mutual restriction. On the other hand, in the extension rod sliding mechanism 100 according to the present embodiment, since the third gap 53 serving as a play is formed, the restriction on the structure for forming the first gap 51 and the restriction on the structure for forming the second gap 52 are compatible. That is, in the extension rod sliding mechanism 100, due to the formation of the third gap 53 serving as a play, the first gap 51 for stably sliding the extension rod 343 in the opening and closing direction (axial direction) and the second gap 52 for stably moving the extension plate 342 in the opening and closing direction (axial direction of the extension rod 343) are ensured.

[0033] To summarize, the stretch rod sliding mechanism, intermediate mold, and mold device to which the present invention is applied can have the following configurations and can take various embodiments. That is, the stretch rod sliding mechanism 100 according to the present embodiment includes a stretch rod 343 that outputs a fluid (e.g., high-pressure air) for stretching a preform, which is an intermediate molded product, by blow molding from the tip 351, a stretch plate 342 joined to the stretch rod 343 and moving in the axial direction of the stretch rod 343, a blow core 341 and a blow core frame 34 in which a through hole 61 for guiding the stretch rod 343 that moves in the axial direction as the stretch plate 342 moves is formed, and a guide rod 344 as a guiding member that penetrates the stretch plate 342 in the axial direction of the stretch rod 343 and guides the stretch plate 342 that moves in the axial direction of the stretch rod 343. The stretch rod sliding mechanism is characterized by having these components.

[0034] Thereby, the guide rod 344 that penetrates the stretch plate 342 in the axial direction of the stretch rod 343 guides the stretch plate 342 that moves in the axial direction of the stretch rod 343, so that the operation of the stretch plate 342 and the operation of the stretch rod 343 joined to the stretch plate 342 can be stabilized. As a result, "core deviation," which causes uneven wall thickness, gate shift, etc., is suppressed, and furthermore, it is suppressed that the blow core 341 and the blow core frame 34 rub against the stretch rod 343 to generate wear powder or that mold biting occurs.

[0035] Here, the guide rod 344 may be a columnar member with both ends fixed. Thereby, the guide rod 344, which is a columnar member with both ends fixed, guides the stretch plate 342 that moves in the axial direction of the stretch rod 343, so that the operation of the stretch plate 342 can be stabilized. As a result, the operation of the stretch rod 343 joined to the stretch plate 342 can be stabilized.

[0036] In addition, a predetermined first gap 51 is formed between the extension rod 343 and the injection core 341 and the injection core frame 343 in the through hole 61. A predetermined second gap 52 is formed between the induction rod 344 and the extension plate 342 in the through hole 63 which is the portion where the induction rod 344 penetrates the extension plate 342. A third gap 53 serving as a clearance may be formed at the joint between the extension rod 343 and the extension plate 342.

[0037] As a result, it becomes possible to design considering the relationship between the structure for forming the first gap 51 required for the sliding of the extension rod 343, the structure for forming the second gap 52 required for the sliding of the induction rod 344, and the structure for forming the third gap 53 serving as a clearance. For this reason, for example, even if the structure for forming the first gap 51 and the structure for forming the second gap 52 restrict each other, since the third gap 53 serving as a clearance is formed, it is possible to achieve both the restriction on the structure for forming the first gap 51 and the restriction on the structure for forming the second gap 52. As a result, the first gap 51 for stably sliding the extension rod 343 and the second gap 52 for stably moving the extension plate 342 in the axial direction (opening and closing direction) of the extension rod 343 can be formed. In addition, since the third gap 53 serving as a clearance is deliberately formed, the assembly for joining the extension rod 343 and the extension plate 342 can be made simple.

[0038] Also, each of the first gap 51 and the second gap 52 may be made smaller than the third gap 53. As a result, each of the first gap 51 and the second gap 52 becomes smaller than the third gap 53, so that the structure forming the first gap 51 and the structure forming the second gap 52 are in a relationship of restricting each other. On the other hand, the third gap 53 can be enlarged so as to make compatible the restriction on the structure forming the first gap 51 and the restriction on the structure forming the second gap 52. As a result, the first gap 51 for stably sliding the extension rod 343 and the second gap 52 for stably moving the extension plate 342 in the axial direction (opening / closing direction) of the extension rod 343 can be formed. Further, since the third gap 53 serving as play is intentionally formed, the assembly for joining the extension rod 343 and the extension plate 342 can be made simple.

[0039] In addition, the intermediate die to which the present invention is applied may have the following configuration and can take various embodiments. That is, the intermediate die 12 according to the present embodiment is an intermediate die 12 having an extension rod sliding mechanism 100. The extension rod sliding mechanism 100 includes an extension rod 343 that outputs a fluid for stretching a preform, which is an intermediate molded product, by blow molding, from a tip portion 351, an extension plate 342 joined to the extension rod 343 and moving in the axial direction of the extension rod 343, a blow core 341 and a blow core frame 34 in which a through hole 61 for guiding the extension rod 343 that moves in the axial direction as the extension plate 342 moves is formed, and a guide rod 344 as a guide member that penetrates the extension plate 342 in the axial direction of the extension rod 343 and guides the extension plate 342 that moves in the axial direction of the extension rod 343. The intermediate die is characterized by having these components.

[0040] Thereby, the guide rod 344 that penetrates the extension plate 342 in the axial direction of the extension rod 343 guides the extension plate 342 that moves in the axial direction of the extension rod 343, so that the operation of the extension plate 342 and the operation of the extension rod 343 joined to the extension plate 342 can be stabilized. As a result, "core deviation" that causes uneven wall thickness, gate deviation, etc. is suppressed, and further, it is suppressed that the blow core 341 and the blow core frame 34 rub against the extension rod 343 to generate wear powder or that die biting occurs.

[0041] In addition, the mold device to which the present invention is applied only needs to have the following configuration and can take various embodiments. That is, the mold device 10 according to the present embodiment is a mold device including a fixed-side mold 11, an intermediate mold 12 having an extension rod sliding mechanism 100, and a movable-side mold 13. The extension rod sliding mechanism 100 of the intermediate mold 12 includes an extension rod 343 that outputs a fluid for stretching a preform, which is an intermediate molded product, by blow molding, from a tip portion 351, an extension plate 342 joined to the extension rod 343 and moving in the axial direction of the extension rod 343, a blow core 341 and a blow core frame 34 in which a through hole 61 for guiding the extension rod 343 that moves in the axial direction as the extension plate 342 moves is formed, and a guide rod 344 as a guide member that penetrates the extension plate 342 in the axial direction of the extension rod 343 and guides the extension plate 342 that moves in the axial direction of the extension rod 343.

[0042] Thereby, since the guide rod 344 that penetrates the extension plate 342 in the axial direction of the extension rod 343 guides the extension plate 342 that moves in the axial direction of the extension rod 343, the operation of the extension plate 342 and the operation of the extension rod 343 joined to the extension plate 342 can be stabilized. As a result, "core deviation", which causes uneven wall thickness, gate deviation, etc., is suppressed, and furthermore, it is suppressed that the blow core 341 and the blow core frame 34 rub against the extension rod 343 to generate wear powder or that mold biting occurs.

[0043] <Others> As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments. Also, the effects of the present invention are not limited to those described in the above-described embodiments. For example, the configuration of the mold device 10 shown in FIG. 1, the configuration of the extension rod sliding mechanism 100 shown in FIG. 2, and the position of the gap shown in FIG. 3 are all merely examples for achieving the object of the present invention and are not particularly limited.

[0044] For example, in the above-described embodiment, as shown in FIG. 1, at least two guide rods 344 are provided, but the number of guide rods 344 is not limited. The guide rod 344 may be one, or may be three or more.

[0045] Also, in the above-described embodiment, the shape of the guide bar 344 is cylindrical, but it is not limited thereto, and for example, it may be prismatic.

Explanation of Reference Numerals

[0046] 10... Mold device, 11... Fixed-side mold, 12... Intermediate mold, 13... Movable-side mold, 21... Fixed platen, 22... Fixed mold, 23... Driving device, 31... Rotating frame, 32... Support frame, 33... Injection core frame, 34... Blowing core frame, 35... Gripping mechanism, 36... Sliding frame, 37... Guide bar, 38... Shaft body, 39... Driving device, 41... Movable platen, 42... Movable split mold, 43... Driving device, 51... First gap, 52... Second gap, 53... Third gap, 61, 62, 63... Through holes, 100... Extension bar sliding mechanism, 221... Injection cavity, 341... Blowing core, 342... Extension plate, 343... Extension bar, 344... Guide bar, 421... Blowing cavity

Claims

1. A stretching rod that outputs a fluid for stretching an intermediate molded product by blow molding from a tip portion, A stretching plate joined to the stretching rod and moving in the axial direction of the stretching rod, A blowing core portion in which a through hole for guiding the stretching rod that moves axially as the stretching plate moves is formed, A guiding member that penetrates the stretching plate in the axial direction of the stretching rod and guides the stretching plate that moves in the axial direction of the stretching rod, characterized by having a stretching rod sliding mechanism.

2. The guiding member is a columnar member with both ends fixed, The stretching rod sliding mechanism according to claim 1.

3. A predetermined first gap is formed between the stretching rod and the blowing core portion in the through hole, A predetermined second gap is formed between the guiding member and the stretching plate at a portion where the guiding member penetrates the stretching plate, A third gap serving as a play is formed at the joint portion between the stretching rod and the stretching plate, The stretching rod sliding mechanism according to claim 1.

4. Each of the first gap and the second gap is smaller than the third gap, The stretching rod sliding mechanism according to claim 3.

5. An intermediate mold having a stretching rod sliding mechanism, The stretching rod sliding mechanism is A stretching rod that outputs a fluid for stretching an intermediate molded product by blow molding from a tip portion, A stretching plate joined to the stretching rod and moving in the axial direction of the stretching rod, A blowing core portion in which a through hole for guiding the stretching rod that moves axially as the stretching plate moves is formed, A guiding member that penetrates the extension plate in the axial direction of the extension rod and guides the extension plate that moves in the axial direction of the extension rod; characterized by having; an intermediate mold.

6. A mold device comprising a fixed-side mold, an intermediate mold having an extension rod sliding mechanism, and a movable-side mold, wherein: the extension rod sliding mechanism of the intermediate mold includes: an extension rod that outputs a fluid for extending an intermediate molded product by blow molding from a tip portion; an extension plate joined to the extension rod and moving in the axial direction of the extension rod; a blow core portion in which a through hole for guiding the extension rod that moves in the axial direction as the extension plate moves is formed; a guiding member that penetrates the extension plate in the axial direction of the extension rod and guides the extension plate that moves in the axial direction of the extension rod; characterized by having; a mold device.

Images