Blow molding machine and method for manufacturing resin liner for pressure container using the same

Abstract

The present invention suppresses the reduction of the sealing performance of a pressure vessel, the deterioration of the sealing component, and reduces the manufacturing labor and cost. A resin liner (2) for a pressure vessel (1) has a cylindrical neck (12) for a cover component (3) to be embedded. A blow molding machine (50) for manufacturing the resin liner (2) includes a pair of molding dies (52) that clamp a blow molding blank (55) from left and right, and a blow rod (54) that cooperates with the molding dies (52) to form the neck (12). The blow rod (54) includes: a blow rod body (61) having an outer peripheral surface of a shape corresponding to the inner peripheral surface of the neck (12); and a ring (63) that is coaxially arranged with the blow rod body (61) and forms an annular recess (62) that is recessed in a direction away from the chamber (56) between the blow rod body (61) and the blow rod body (61) in order to form the outer peripheral surface of the front end portion (34) of the neck (12). The outer peripheral surface of the front end portion (34) of the neck portion (12) is transferred with the inner peripheral surface shape of the ring portion (12) to form a smooth surface without a parting line.

Description

Technical Field

[0001] The present invention relates to a blow molding machine for manufacturing a resin liner for a pressure container and a method for manufacturing a resin liner for a pressure container using the blow molding machine. Background Art

[0002] It is known that there is a resin pressure vessel for containing high-pressure gas or liquid such as compressed hydrogen and LPG (liquefied petroleum gas). Such a pressure vessel includes: a resin liner having a container portion for containing the gas or liquid and a cylindrical protrusion (neck) protruding outward from the container portion; a metal cover member, which is arranged on the outer periphery of the neck and has a disc-shaped surface contact portion that is in surface contact with the outer surface of the container portion; and a fiber-reinforced resin layer that covers the outer surface of the container portion of the resin liner and the surface contact portion of the cover member (see patent document 1). In this pressure vessel, in order to prevent the generation of a leakage path, a valve is provided between the neck and the valve inserted into the neck (see patent document 1). Figure 5 ), between the neck and the cover member (see Patent Document 1 Figure 3 ) and the like are provided with O-rings.

[0003] In addition, the applicant has proposed a pressure vessel and a method for manufacturing the same, which, when manufacturing a resin liner having a multilayer structure including a gas barrier layer by blow molding, prevents the gas barrier layer from being exposed on the abutting surface of the sealing component on the periphery of the neck of the resin liner (Patent Document 2). The pressure vessel is made by cutting off at least the gas barrier layer and the layer outside it from the wall portion of at least the portion abutting the sealing component at the neck of the resin liner, so that the gas barrier layer is not exposed in the portion. Thus, it is possible to prevent the sealing performance from being reduced and the sealing component from being deteriorated.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 4599380

[0007] Patent Document 2: Japanese Patent Application Publication No. 2017-89768 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In Patent Document 1 Figure 5 In the case of a pressure vessel having an O-ring sandwiched between the neck and the valve as described in , the O-ring is arranged between the fall-off prevention wall extending inward from the inner circumference of the neck of the resin liner and the large diameter portion of the valve in a manner sandwiched in the axial direction of the valve. Therefore, there is a possibility that the self-sealing function (resin liner withstands the high pressure in the container, thereby improving the airtightness of the sealing component) does not work and the sealing performance is reduced.

[0010] In Patent Document 1 Figure 3 In the case of a pressure vessel having an O-ring sandwiched between the neck and the cover member as described in , the O-ring is arranged on the outer peripheral side of the neck so that the self-sealing function works, but a small gap generated on the dividing surface of the mold and a parting line formed by the step difference appear on the outer peripheral surface of the neck formed by the blow molding method. Therefore, there is a possibility that the sealing performance is reduced and the sealing member is deteriorated due to the parting line.

[0011] In the pressure vessel described in Patent Document 2, since the outer peripheral portion of the portion of the neck abutting against the sealing member is cut away, no parting line appears in this portion. However, smooth finishing of the cut surface increases processing labor and cost.

[0012] In view of the above background, an object of the present invention is to provide a blow molding machine for manufacturing a resin liner and a method for manufacturing a resin liner using the blow molding machine, which can suppress the reduction in sealing performance of a pressure container and the degradation of a sealing member and can reduce manufacturing labor and cost.

[0013] Means for solving problems

[0014] In order to solve the above-mentioned problems, one embodiment of the present invention is a blow molding machine (50) for manufacturing a resin liner (2) for a pressure container (1) having a cylindrical neck (12) for embedding a cover member (3), the blow molding machine (50) comprising: a pair of molding dies (52), which are combined to clamp a blow-molded blank (55) to be formed into the resin liner from left and right, and define a cavity (56) having a shape corresponding to the outer contour of the main body (11) of the resin liner; and a blow rod (53), which is located at the blow-molded blank. The inner portion thereof has an air supply port (58) and cooperates with the molding die to form the neck, the blow rod comprising: a blow rod body portion (61) which forms an air supply path (59) leading to the air supply port and has an outer peripheral surface having a shape corresponding to the inner peripheral surface of the neck; and a ring portion (63) which is coaxially arranged relative to the blow rod body portion and forms an annular recess (62) which is recessed in a direction away from the chamber between the blow rod body portion and the blow rod body portion in order to form the outer peripheral surface of the front end portion (34) of the neck.

[0015] According to this configuration, the front end of the neck of the resin liner is formed by an annular recess, and the inner peripheral surface shape of the annular portion is transferred to the outer peripheral surface of the front end of the neck. As a result, the outer peripheral surface of the front end of the neck can be formed into a smooth surface without a parting line. Therefore, by installing the sealing component sandwiched between the neck and the cover component in a manner of abutting against the outer peripheral surface of the front end of the neck, it is possible to prevent the sealing performance from being reduced and the sealing component from being deteriorated. In addition, by arranging the sealing component on the outside of the neck, the sealing performance is improved by the self-sealing function.

[0016] Preferably, the blow rod is formed with an air discharge passage (64) extending from the bottom of the annular recess.

[0017] According to this configuration, the blow-molded blank can easily reach the bottom of the annular recessed portion.

[0018] Preferably, the ring portion is fixed to the blow rod body portion, and the blow rod is provided so as to be movable in the axial direction relative to the paired molding dies.

[0019] According to this configuration, even when the blow-molded blank does not reach the bottom of the annular recessed portion by only closing the molding mold, the blow-molded blank can be spread to the bottom of the annular recessed portion by moving the blow rod toward the cavity. Thus, the axial length of the front end portion of the neck where the parting line does not appear can be increased.

[0020] Preferably, the ring portion is provided so as to be slidable in the axial direction relative to the blowing rod body portion.

[0021] According to this structure, by sliding the ring portion axially relative to the blow rod body in a direction close to the chamber, the blow-molded blank can be spread to the bottom of the annular recess without moving the blow rod body axially. Thus, the axial length of the front end of the neck without a parting line can be increased.

[0022] In addition, in order to solve the above-mentioned problem, one embodiment of the present invention is a method for manufacturing the resin liner of the blow molding machine of the above-mentioned structure, which includes the following steps: a blow molding blank configuration step, which configures the blow molding blank on the outer peripheral side of the blow rod and between the pair of molding dies separated from each other on the left and right ( Figure 5 (A)); a mold closing step, which performs a mold closing of the pair of molding dies to clamp the blow molding blank into ( Figure 5 (B)); and a blow molding step, which supplies air from the air supply port of the blow rod to the interior of the blow molded blank to expand the blow molded blank and transfer the inner surface shape of the cavity to the main body portion of the blow molded blank that constitutes the resin liner ( Figure 5(C)), between the mold closing step and the blow molding step, the blow molded blank is allowed to penetrate the annular recess, and the inner circumferential surface shape of the annular portion is transferred to the front end portion of the blow molded blank that constitutes the neck.

[0023] According to this configuration, the outer peripheral surface of the front end of the neck can be formed into a smooth surface without a parting line. Therefore, by installing the sealing member between the neck and the cover member, the sealing performance can be improved based on the self-sealing function and the sealing member can be prevented from deteriorating.

[0024] Preferably, between the mold clamping step and the blow molding step, the annular recessed portion is moved in a direction approaching the cavity along the axial direction of the blow pin.

[0025] According to this configuration, even if the blow-molded blank does not reach the bottom of the annular recess during the mold closing process, the blow-molded blank can be moved toward the cavity so that the blow-molded blank reaches the bottom of the annular recess. Thus, the axial length of the front end of the neck where the parting line does not appear can be increased.

[0026] Preferably, the ring portion is fixed to the blow rod body, the blow rod is movably provided in the axial direction, and the annular recessed portion is moved by moving the blow rod in the axial direction between the mold clamping step and the blow molding step.

[0027] According to this configuration, by moving the blow pin in a direction approaching the cavity, the annular recessed portion can be moved in the axial direction, and the blow molded blank can be spread to the bottom of the annular recessed portion.

[0028] Preferably, the ring portion is slidably arranged in the axial direction relative to the blow rod body, and the annular recess is moved by moving the ring portion in the axial direction relative to the blow rod body between the mold clamping step and the blow molding step.

[0029] According to this configuration, by sliding the ring relative to the blow rod body toward the cavity, the annular recess can be moved axially without moving the blow rod body axially, so that the blow molded blank reaches the bottom of the annular recess.

[0030] Effects of the Invention

[0031] As described above, according to the present invention, a blow molding machine for manufacturing a resin liner and a method for manufacturing a resin liner using the blow molding machine can be provided, which can suppress the reduction in the sealing performance of a pressure container and the deterioration of a sealing member and can reduce the manufacturing labor and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1It is a partially cutaway longitudinal sectional view showing a pressure vessel according to an embodiment.

[0033] Figure 2 yes Figure 1 An enlarged view of the main part.

[0034] Figure 3 yes Figure 1 A perspective view of the main parts of the resin liner shown.

[0035] Figure 4 This is a perspective view of a main part of a resin liner according to another example.

[0036] Figure 5 It is a schematic explanatory diagram of the method for manufacturing the resin liner according to the embodiment.

[0037] Figure 6 yes Figure 5 A cross-sectional view of a main part of an example of a blow molding machine shown.

[0038] Figure 7 is used Figure 6 1 is an explanatory diagram of a method for molding a neck portion of a blow molding machine.

[0039] Figure 8 is used Figure 6 An explanatory diagram of a molding method according to a modified example of the neck portion of the blow molding machine shown.

[0040] Fig. 9 yes Figure 5 A cross-sectional view of a main part of another example of the blow molding machine shown.

[0041] Fig.10 is used Fig. 9 1 is an explanatory diagram of a method for molding a neck portion of a blow molding machine. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0043] Figure 1 FIG. 1 is a partially cutaway longitudinal sectional view showing a pressure vessel 1 according to an embodiment. Figure 1 As shown, the pressure vessel 1 comprises: a resin liner 2 made of resin, which defines a storage chamber 2a for storing gas or liquid; a metal cover member 3, which is mounted on the outer surface of the resin liner 2; and a reinforcement layer 4, which is stacked on the outer side of the resin liner 2 and the cover member 3. An accessory device is mounted on the cover member 3. In the example shown in the figure, as an accessory device, a valve 5 for injecting and discharging high-pressure gas or liquid is installed in a manner inserted into the cover member 3.

[0044] The resin liner 2 has a hollow cylindrical main body 11 forming a receiving chamber 2a and a cylindrical neck 12 formed continuously with the main body 11 in a manner protruding outward from the main body 11. The resin liner 2 has a single-layer structure in the present embodiment. The material of the resin liner 2 is selected based on the gas or liquid to be received and the filling conditions (e.g., filling pressure). For example, polyethylene (PE), high-density polyethylene (HDPE), polyamide, polyketone, polyphenylene sulfide (PPS), etc. can be used. In the present embodiment, the resin liner 2 is composed of high-density polyethylene (HDPE).

[0045] In other embodiments, the resin liner 2 may also be formed into a multilayer structure. For example, the resin liner 2 may also be formed into a laminated structure of more than three layers including a gas barrier layer and two resin layers sandwiching the gas barrier layer. As the material of the gas barrier layer, ethylene vinyl alcohol copolymer resin (EVOH resin) is preferred. In addition, a material obtained by mixing fine thin plate-like polyamide sheets into high-density polyethylene (HDPE) may also be used.

[0046] The cover member 3 includes: a cylindrical cover tube portion 13, which is externally fitted on the neck portion 12 of the resin liner 2; and an annular flange portion 14, which protrudes radially outward at the base end of the cover tube portion 13 on the resin liner 2 side. The cover tube portion 13 and the flange portion 14 are formed integrally and continuously. When the cover tube portion 13 is externally fitted on the neck portion 12, the flange portion 14 is along the outer surface of the neck portion 12 in the main body portion 11 of the resin liner 2.

[0047] The reinforcing layer 4 is made of, for example, FRP (fiber reinforced plastic), and plays a role in reinforcing the compressive strength of the resin liner 2. The reinforcing layer 4 is provided in a manner covering the outer surface of the main body 11 of the resin liner 2 and the flange 14 of the cover member 3, for example, by using a fiber winding method in which a fiber bundle impregnated with a resin is wound and then the resin is cured. It should be noted that the lamination method of the reinforcing layer 4 is not particularly limited, and other methods such as a sheet winding method in which a resin sheet in which fibers are embedded is wound may also be used.

[0048] When the reinforcing layer 4 is formed, the cover member 3 forms one of a pair of clip portions for supporting the resin liner 2. An unillustrated engaging portion (e.g., a threaded portion) for mounting a boss, which constitutes the other of the pair of clip portions, is formed at the other end of the resin liner 2 on the opposite side of the cover member 3, or a member (not shown) having the same structure as the cover member 3 is mounted.

[0049] Figure 2 yes Figure 1 A magnified view of the main part. Figure 2As shown, the cover cylinder portion 13 includes a cover large diameter portion 15 disposed on the flange portion 14 side and having an inner diameter substantially the same as the outer diameter of the neck portion 12, and a cover small diameter portion 16 disposed on the front end side and having an inner diameter substantially the same as the inner diameter of the neck portion 12. An annular first sealing groove 18 is formed on the cover large diameter portion 15 on the cover small diameter portion 16 side, and the annular first sealing groove 18 accommodates the first sealing member 17 interposed between the resin liner 2 and the cover member 3. A cover sealing surface 19 composed of an inner peripheral surface that is annular and becomes a smooth surface is formed on the cover small diameter portion 16 on the cover large diameter portion 15 side, and a cover coupling portion 20 for coupling with the valve 5 is formed on the front end side of the cover small diameter portion 16. The first sealing member 17 may be, for example, an O-ring. The cover coupling portion 20 is an internal thread in the illustrated example, but is not limited thereto.

[0050] The valve 5 includes a valve insertion portion 21 inserted into the cover tube portion 13 and a valve exposure portion 22 arranged on the outer side of the cover tube portion 13 and exposed to the outside. A valve coupling portion 23 coupled to the cover coupling portion 20 of the cover member 3 is formed on the valve exposure portion 22 side of the valve insertion portion 21. In the present embodiment, the valve coupling portion 23 is an external thread. The valve exposure portion 22 is integrally provided with a tool holding portion 22a (for example, a hexagonal portion) for coupling (fastening) the valve coupling portion 23 to the cover coupling portion 20. The portion of the valve insertion portion 21 located on the front end side compared to the valve coupling portion 23 has an outer diameter that is substantially the same as the inner diameter of the neck 12 and the inner diameter of the small diameter portion 16 of the cover. In the installed state of the valve 5, the valve insertion portion 21 has a length up to the large diameter portion 15 of the cover and enters the interior of the neck 12. An annular second seal groove 25 is formed on the outer peripheral surface of the valve insertion portion 21 at a portion corresponding to the cover seal surface 19. The annular second seal groove 25 accommodates a second seal member 24 interposed between the valve 5 and the cover member 3. The second seal member 24 may be, for example, an O-ring.

[0051] Figure 3 yes Figure 1 The main part of the resin liner 2 is shown in FIG. Figure 2 and Figure 3 As shown, in order to prevent the cover member 3 from rotating around the axis, a coupling structure 31 for coupling with the cover member 3 is formed on the base end side of the neck 12 of the resin liner 2. The coupling structure 31 is formed in a polygonal shape (a hexagonal shape in the example shown in the figure) in this embodiment, and is an expanded diameter portion with respect to the front end side of the neck 12. A corresponding coupling structure 32 ( Figure 2 ). The corresponding engagement structure 32 is formed in a polygonal (hexagonal) shape in the present embodiment, and is a recessed portion formed on the bottom surface of the cover member 3 .

[0052] In other examples, the coupling structure 31 may also be as follows Figure 4As shown, an external thread is formed on the base end side of the neck 12. The outer diameter of the external thread is set larger than the outer diameter of the front end side of the neck 12. In this case, the corresponding engagement structure 32 provided on the cover member 3 is an internal thread that is screwed with the external thread, which can not only prevent the cover member 3 from rotating around the axis relative to the neck 12 of the resin liner 2, but also prevent movement in the axial direction.

[0053] The resin liner 2 is formed by blow molding. Figure 3 and Figure 4 As shown, the outer surface of the resin liner 2 is formed with a pair of molding dies 52 (see Figure 5 ) at the dividing position. The parting line 33 is a linear protrusion protruding from the outer surface of the resin liner 2, and is formed on the entire circumference of the outer surface of the main body 11 of the resin liner 2 and the outer surface of the base end side portion of the neck 12 including the coupling structure 31. The parting line 33 is not formed on the inner surface of the resin liner 2 and the outer surface of the front end portion 34 of the neck 12.

[0054] A burr 35 is formed in a circular ring shape between the front end portion 34 of the neck 12 where the parting line 33 is not formed and the base end portion where the parting line 33 is formed. The burr 35 is removed after blow molding. The removal method is not particularly limited, and for example, cutting, grinding, laser processing, etc. can be used. On the other hand, the outer surface of the front end portion 34 of the neck 12 where the parting line 33 is not formed is transferred to the blow rod 53 (see FIG. 5 ) which functions as a mold. Figure 6 The detailed structure will be described later. The shape of the product is smoothly formed during blow molding, and no secondary processing after blow molding is performed.

[0055] like Figure 2 As shown, the first sealing member 17 abuts against the outer peripheral surface of the front end portion 34 of the neck 12 where the parting line 33 does not appear. If the parting line 33 appears on the surface of the neck 12 where the first sealing member 17 abuts, there is a possibility that the sealing performance is reduced and the first sealing member 17 is deteriorated due to the parting line 33. In contrast, in the present embodiment, since the parting line 33 does not appear on the surface of the neck 12 where the first sealing member 17 abuts, it is possible to prevent the sealing performance from being reduced and the first sealing member 17 from being deteriorated. In addition, by arranging the first sealing member 17 on the outside of the neck 12, the first sealing member 17 exerts a self-sealing function. As a result, the sealing performance between the resin liner 2 and the cover member 3 is improved.

[0056] Next, refer to Figure 5 The following is an overview of a method for manufacturing the resin liner 2 configured as described above. Figure 5 The blow molding machine 50 shown is used for manufacturing. Before describing the manufacturing method, the schematic structure of the blow molding machine 50 will be described.

[0057] like Figure 5 As shown in (A), the blow molding machine 50 includes a mold device 51, a pair of molding dies 52 arranged below the mold device 51, a blow rod 53, and an air supply source 54. The mold device 51 is supplied with a resin as a material of the resin liner 2 heated and melted by an extruder. The mold device 51 shapes the resin supplied from the extruder using a mold and a core and supplies it downward. The resin material extruded downward from the mold device 51 is a cylindrical blow molding blank 55 to be used as the resin liner 2.

[0058] The paired molding dies 52 are configured to be openable and closable. Figure 5 In the open state shown in (A), the blow molding blank 55 is supplied from above to between the paired molding dies 52. The paired molding dies 52 are clamped to sandwich the blow molding blank 55 to be formed into the resin liner 2 from left and right. Figure 5 (B) shows a closed state. In the closed state, the pair of molding dies 52 defines a cavity 56 having a shape corresponding to the outer contour of the main body 11 of the resin liner 2. In addition, the pair of molding dies 52 defines a blow rod insertion hole 57 from the outside to the cavity 56. In the present embodiment, the blow rod insertion hole 57 is formed at the lower end of the pair of molding dies 52. In other embodiments, the blow rod insertion hole 57 can be formed at the upper end of the pair of molding dies 52, or at both the upper end and the lower end of the pair of molding dies 52.

[0059] The blow rod 53 is arranged in a position corresponding to the lower end of the paired molding die 52 in the axial direction, and is configured to be movable along the axial direction. In other words, the blow rod 53 can move in the axial direction relative to the paired molding die 52. In other examples, the paired molding die 52 can also be configured to be movable in the axial direction of the blow rod 53. Figure 5 In the closed state of the molding die 52 shown in (B), the blow rod 53 passes through the blow rod insertion hole 57 and is arranged at a height where the upper part is located in the cavity 56. The blow rod 53 has an air supply port 58 located inside the blow molding blank 55 in the closed state of the molding die 52 at the front end portion, and an air supply path 59 to the air supply port 58 is formed inside. The blow rod 53 supplies the air supplied from the air supply source 54 from the air supply port 58 to the inside of the blow molding blank 55.

[0060] The process of manufacturing the resin liner 2 using the blow molding machine 50 constructed as described above includes: Figure 5 The blow molding blank arrangement step shown in (A) Figure 5 The mold clamping process shown in (B) Figure 5 The blow molding process shown in (C) and Figure 5In the blow molding blank configuration process, as shown in (D). Figure 5 As shown in (A), a mold device 51 is used to form a cylindrical blow molding blank 55 to be used as the resin liner 2. The blow molding blank 55 is arranged on the outer peripheral side of the blow rod 53 and between the pair of molding molds 52 separated from each other on the left and right. In the mold closing process, as shown in FIG. Figure 5 As shown in (B), the paired molding dies 52 are closed to sandwich the blow molding blank 55. In the blow molding process, as Figure 5 As shown in (C), air is supplied from the air supply port 58 of the blow rod 53 to the interior of the blow molded blank 55 to expand the blow molded blank 55, and the inner surface shape of the cavity 56 is transferred to the main body 11 of the blow molded blank 55 that constitutes the resin liner 2.

[0061] In the mold opening process, Figure 5 As shown in (D), the paired molding dies 52 are opened in a manner separated from each other on the left and right, and the paired molding dies 52 are removed from the blow molding blank 55 in the shape of the resin liner 2. In addition, the blow rod 53 is removed from the blow molding blank 55 in the shape of the resin liner 2. There is no order of opening the paired molding dies 52 and removing the blow rod 53. The burrs 35 are removed using a cutter.

[0062] It should be noted that after the manufacturing process of the resin liner 2 is completed, Figure 1 and Figure 2 In the state shown in the figure where the first sealing member 17 is interposed, the cover member 3 is mounted on the outer periphery of the neck 12. Thereafter, the outer periphery of the resin liner 2 and the cover member 3 is covered with the reinforcing layer 4, thereby manufacturing the pressure vessel 1. In addition, auxiliary devices such as a valve 5 are mounted on the cover member 3 as required.

[0063] Next, refer to Figure 6 The detailed structure of the blow pin 53 and the details of the method for manufacturing the resin liner 2 will be described. Figure 6 yes Figure 5 1 is a cross-sectional view of the main parts of an example of a blow molding machine 50 shown in FIG. The blow rod 53 has a blow rod body 61, which is formed with an air supply path 59 leading to an air supply port 58, and has an outer peripheral surface of a shape corresponding to the inner peripheral surface of the neck 12 of the resin liner 2. In addition, the blow rod 53 is coaxially arranged with respect to the blow rod body 61, and has a ring portion 63 between the blow rod body 61 and the blow rod body 61 in order to form the outer peripheral surface of the front end portion 34 of the neck 12, and the ring portion 63 is formed with an annular recess 62 that is recessed in a direction away from the cavity 56.

[0064] The ring 63 is integrally formed with the blow rod body 61 and fixed to the blow rod body 61. The blow rod 53 is formed with an air discharge passage 64 extending from the bottom of the annular recess 62. The air discharge passage 64 can be provided in either the ring 63 or the blow rod body 61.

[0065] By constructing the blowing rod 53 in the above manner, Figure 5 (B) The mold closing process Figure 5 During the blow molding process (C), especially during the mold closing process, the blow molded blank 55 enters the annular recess 62. The inner peripheral surface shape of the ring portion 63 is transferred to the portion of the blow molded blank 55 that constitutes the front end portion 34 of the neck 12. As a result, the outer peripheral surface of the front end portion 34 of the neck 12 is formed as shown in FIG. Figure 3 and Figure 4 The surface shown is a smooth surface without a parting line 33. Therefore, it is possible to prevent the sealing performance of the first sealing member 17 interposed between the neck 12 and the cover member 3 from being reduced or deteriorated.

[0066] Figure 7 is used Figure 6 FIG. 1 is an explanatory diagram of a method for molding the neck 12 of a blow molding machine 50 shown in FIG. In the blow molding blank arrangement step, the blow pin 53 is arranged at a predetermined position for blow molding, such as Figure 7 As shown in (A), by closing the paired molding dies 52, the blow-molded blank 55 enters the annular recess 62 and spreads to the bottom of the annular recess 62. As a result, the inner peripheral surface shape of the ring 63 is transferred to the blow-molded blank 55. At this time, by forming an air exhaust passage 64 extending from the bottom of the annular recess 62 on the blow rod 53 as described above, the blow-molded blank 55 can easily spread to the bottom of the annular recess 62. Alternatively, negative pressure can be applied to the air exhaust passage 64, so that the blow-molded blank 55 can easily spread to the bottom of the annular recess 62.

[0067] Then, if Figure 7 As shown in (B), in the blow molding process, air is supplied from the air supply port 58 of the blow rod 53 to the blow molding blank 55. As a result, the blow molding blank 55 is expanded and closely attached to the inner surface of the cavity 56, so that the shape of the paired molding molds 52 (the inner surface shape of the cavity 56) is transferred to the blow molding blank 55.

[0068] Figure 8 is used Figure 6 FIG. 1 is an explanatory diagram of a molding method of a modified example of the neck 12 of the blow molding machine 50 shown in FIG. Figure 8As shown in (A) and (B) of FIG. 1 , the blow rod 53 is moved axially between the mold closing step and the blow molding step, which is different from the above-mentioned embodiment. Specifically, in the blow molding blank configuration step, as shown in FIG. Figure 8 As shown in (A), the blow rod 53 is arranged slightly below the predetermined position for blow molding. Then, between the mold closing step and the blow molding step, as shown in FIG. Figure 8 As shown in (B), the annular recess 62 moves in the direction (upward) approaching the chamber 56 along the axial direction of the blowing rod 53. Since the ring portion 63 is fixed to the blowing rod body 61 as described above, in this embodiment, the annular recess 62 moves by the blowing rod 53 moving upward along the axial direction.

[0069] Therefore, even in the Figure 8 As shown in (A), when the blow molded blank 55 does not reach the bottom of the annular recess 62 during the mold closing process, the blow molded blank 55 also spreads to the bottom of the annular recess 62. In addition, the blow rod 53 is arranged in a manner that can move axially relative to the paired molding molds 52, and the manufacturing method of the resin liner 2 includes a step of moving the blow rod 53 in the axial direction, thereby increasing the axial length of the front end portion 34 of the neck 12 where the parting line 33 does not appear.

[0070] Fig. 9 yes Figure 5 A cross-sectional view of the main parts of another example of the blow molding machine 50 shown. It should be noted that the elements that are the same or similar to the above examples are marked with common reference numerals and repeated descriptions are omitted. In this example, the ring portion 63 is formed separately from the blow rod main body 61 and is configured to be able to slide axially relative to the blow rod main body 61. An air exhaust passage 64 is formed between the ring portion 63 and the blow rod main body 61.

[0071] In the case where the resin liner 2 is manufactured by blow molding using the blow pin 53, the resin liner 2 may also be manufactured by Figure 7 , Figure 8 Made in the manner of Fig.10 Manufactured in this way. Fig.10 is used Fig. 9 FIG. 5 is an explanatory diagram of a method for molding the neck 12 of a blow molding machine 50 shown in FIG. Fig.10 As shown in (A), the ring portion 63 is arranged slightly below the blow rod body 61. Then, between the mold closing step and the blow molding step, as shown in FIG. Fig.10 As shown in FIG. 5B , the ring portion 63 slides relative to the blow rod body 61 in a direction approaching the chamber 56 (upward), so that the annular recessed portion 62 moves in a direction approaching the chamber 56 .

[0072] Therefore, even in the Fig.10 As shown in (A), when the blow molded blank 55 does not reach the bottom of the annular recess 62 during the mold closing process, the blow rod body 61 is not moved in the axial direction, and the blow molded blank 55 also reaches the bottom of the annular recess 62. As a result, the axial length of the front end portion 34 of the neck 12 where the parting line 33 does not appear can be increased.

[0073] The above is a description of a specific embodiment, but the present invention is not limited to the above embodiment, and can be widely modified within the scope of the gist thereof. In addition, not all of the components shown in the above embodiment are essential, and can be appropriately selected.

[0074] Description of Reference Numerals

[0075] 1. Pressure vessel

[0076] 2 Resin lining

[0077] 3 Cover parts

[0078] 11 Main body

[0079] 12 Neck

[0080] 33 Parting line

[0081] 34 Front end

[0082] 35 Burr

[0083] 50 Blow molding machine

[0084] 52 Forming mold

[0085] 53 Blowing rod

[0086] 55 Blow molding blank

[0087] 56 Chamber

[0088] 58 Air supply port

[0089] 59 Air supply line

[0090] 61 Blowing rod body

[0091] 62 Annular concave part

[0092] 63 Ring

[0093] 64 Air exhaust passage

Claims

1. A blow molding machine for manufacturing a resin liner for a pressure container having a cylindrical neck portion on which a cover member is fitted, the blow molding machine comprising: A pair of molding dies, which are combined to sandwich the blow-molded blank to be formed into the resin liner from left and right, and define a cavity having a shape corresponding to the outer contour of the main body of the resin liner; as well as a blow rod having an air supply port at a portion located inside the blow molding blank and cooperating with the molding die to mold the neck, The blow rod has: a blow rod main body, which forms an air supply path to the air supply port and has an outer peripheral surface with a shape corresponding to the inner peripheral surface of the neck; and a ring portion, which is coaxially arranged relative to the main body of the blowing rod, and forms an annular recessed portion recessed in a direction away from the chamber between the ring portion and the main body of the blowing rod in order to form the outer peripheral surface of the front end of the neck, The blow rod is formed with an air discharge passage extending from the bottom of the annular recess.

2. The blow molding machine according to claim 1, characterized in that: The ring portion is fixed to the blow rod body portion, and the blow rod is provided in a manner movable in the axial direction relative to the paired molding dies.

3. The blow molding machine according to claim 1, characterized in that: The ring portion is provided in a manner capable of sliding in the axial direction relative to the blowing rod body portion.

4. A manufacturing method, which is a manufacturing method of the resin liner using the blow molding machine according to any one of claims 1 to 3, wherein the manufacturing method comprises the following steps: a blow molding blank arranging step of arranging the blow molding blank on the outer peripheral side of the blow rod and between the pair of molding dies separated from each other on the left and right sides; a mold closing step of closing the paired molding dies to sandwich the blow molding blank; and a blow molding step of supplying air from the air supply port of the blow rod into the interior of the blow molded blank to expand the blow molded blank and transfer the inner surface shape of the cavity to the main body portion of the blow molded blank constituting the resin liner, Between the mold clamping step and the blow molding step, the blow molded material is allowed to enter the annular recessed portion, and the inner peripheral surface shape of the ring portion is transferred to a portion of the blow molded material constituting the front end portion of the neck portion.

5. The manufacturing method according to claim 4, characterized in that: Between the mold clamping step and the blow molding step, the annular recessed portion is moved in a direction approaching the cavity along the axial direction of the blow pin.

6. The manufacturing method according to claim 5, characterized in that: The ring portion is fixed to the main body of the blowing rod, and the blowing rod is arranged in a manner that it can move along the axial direction. The annular recessed portion is moved by moving the blow pin in the axial direction between the mold clamping step and the blow molding step.

7. The manufacturing method according to claim 5, characterized in that: The ring portion is arranged to be slidable along the axial direction relative to the main body of the blowing rod, The annular recessed portion is moved by moving the ring portion in the axial direction relative to the blow rod body portion between the mold clamping step and the blow molding step.

8. The manufacturing method according to claim 4, characterized in that: When the blow molded blank enters the annular recess, negative pressure is applied to the air exhaust passage.

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