Pressure vessel and method of manufacturing a pressure vessel

Abstract

A pressure vessel (1) in which a liner (2) and an embedded member (3) are integrally formed by blow molding of the liner (2), the embedded member (3) having an inner diameter opening portion (27) and being in a cylindrical shape, the liner (2) being integrally formed with the embedded member (3) by blow molding of a parison inserted into the inner diameter opening portion (27). Since the liner (2) is inserted into the inside of the embedded member (3) and blow molded, extrusion portions can be prevented from being generated. Accordingly, fluid leakage between the liner (2) and the embedded member (3) can be prevented while the strength is improved.

Description

Technical Field

[0001] This invention relates to a pressure vessel and a method for manufacturing the pressure vessel. Background Technology

[0002] As background technology for this invention, there exists a technique in Patent Document 1. This technique relates to a method of manufacturing a liner for sealing high-pressure fluids, etc., by blow molding. The liner, made of resin, has a connector (insert) inserted into the inside of a parison, which is a semi-fluid resin, and is integrally formed with the connector by blow molding.

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] Patent Document 1: Japanese Invention Patent Publication No. JP9-119598 Summary of the Invention

[0006] [The technical problem that the invention aims to solve]

[0007] However, in the molding process around the joint in Patent Document 1, since the preform is clamped onto the joint from the outside using a split mold, a pinched portion (a portion with uneven thickness due to pinching) is created in the inner liner portion surrounding the outer periphery of the joint. If this pinched portion is created, a gap can easily form between the joint and the inner liner, potentially causing the sealed fluid to leak easily from the manufactured pressure vessel. Furthermore, if a pinched portion is formed, stress concentration points will appear due to the uneven thickness of the inner liner, which may lead to a decrease in the strength of the pressure vessel.

[0008] Therefore, the technical problem to be solved by the present invention is to provide a pressure vessel that improves strength while making it less prone to fluid leakage, and a method for manufacturing the pressure vessel.

[0009] [Technical solutions used to solve technical problems]

[0010] The present invention is a pressure vessel in which an inner liner and an insert member are integrally formed by blow molding of the inner liner. The insert member has an inner diameter opening and is cylindrical. The inner liner is integrally formed with the insert member by blow molding a preform through the inner diameter opening.

[0011] According to the present invention, since the inner liner is inserted into the inside of the embedded component during blow molding, the formation of a squeezed portion can be prevented. Accordingly, while increasing strength, it is less likely for fluid to leak between the inner liner and the embedded component.

[0012] Alternatively, preferably, the inner liner has an injection port that contacts the inner diameter opening. During the blow molding process, an air-blowing needle with a stepped portion on the outer peripheral surface is inserted from the outside into the portion of the preform that becomes the injection port, thereby forming a sealing surface at the injection port.

[0013] According to the present invention, the molding cycle can be shortened and the molding accuracy of the sealing surface can be improved.

[0014] Another technical solution of the present invention includes a first step, a second step, and a third step, wherein, in the first step, a cylindrical inserting member having an inner diameter opening is held; in the second step, a preform is inserted into the inner diameter opening of the inserting member and into the mold; in the third step, after the second step, air is supplied through an air-blowing needle, and the preform is transferred to the forming surface of the mold and the inner diameter opening for blow molding.

[0015] According to the present invention, since the inner liner is inserted into the inside of the embedded component during blow molding, the formation of a squeezed portion can be prevented. Accordingly, while increasing strength, it is less likely for fluid to leak between the inner liner and the embedded component.

[0016] Alternatively, preferably, in the third step, the air-blowing needle with a stepped portion on its outer peripheral surface is inserted from the outside into the portion of the blank that contacts the inner diameter opening, which becomes the injection / discharge port, thereby forming a sealing surface at the injection / discharge port.

[0017] According to the present invention, the molding cycle can be shortened and the molding accuracy of the sealing surface can be improved.

[0018] [Invention Effects]

[0019] According to the present invention, a pressure vessel that is not prone to fluid leakage while improving strength can be provided, and a method for manufacturing the pressure vessel. Attached Figure Description

[0020] Figure 1 This is a longitudinal sectional view of the pressure vessel according to the first embodiment of the present invention.

[0021] Figure 2 This is a longitudinal sectional view illustrating the first and second steps of the method for manufacturing a pressure vessel according to the first embodiment of the present invention.

[0022] Figure 3 This is a longitudinal sectional view illustrating the third step of the manufacturing method of the pressure vessel according to the first embodiment of the present invention.

[0023] Figure 4 This is a longitudinal sectional view around the embedded part of a pressure vessel formed using a blow pin with a stepped portion, in the second embodiment of the present invention.

[0024] Figure 5 This is a longitudinal sectional view around the embedded part in the third step of the pressure vessel manufacturing method according to the second embodiment of the present invention, after the air-blowing needle has been inserted into the inlet of the preform.

[0025] Figure 6 This is a longitudinal sectional view around the embedded part of a pressure vessel formed using a blow needle with a stepped portion, in the third embodiment of the present invention.

[0026] Figure 7 This is a longitudinal sectional view of the air-blowing needle and the embedded component in the third embodiment of the present invention.

[0027] Figure 8 This is a longitudinal sectional view of the embedded part after the air-blowing needle of the third embodiment of the present invention has been inserted from the inlet of the blank. Detailed Implementation

[0028] The embodiments of the present invention will be described below with several examples.

[0029] [First Implementation]

[0030] Figure 1 This is a longitudinal sectional view of the pressure vessel according to the first embodiment of the present invention. In the figures described below, for ease of explanation, the upper side of the figure is sometimes taken as the upper side and the lower side as the lower side, but this does not limit the present invention.

[0031] like Figure 1 As shown, the pressure vessel 1 according to this embodiment is a hollow container used to fill high-pressure fluids such as hydrogen. The pressure vessel 1 has an inner liner 2, embedded parts 3 such as connectors, and a reinforcing layer 4. In addition, the pressure vessel 1 of this embodiment has embedded parts 3 on both the upper and lower parts, but it is also possible to have them on only one of them.

[0032] The inner liner 2 is a hollow container made of resin and is a component forming the inner side of the pressure vessel 1. The inner liner 2 is formed with approximately the same thickness. The inner liner 2 has a main body 21, a shoulder 22, and an inlet / outlet 23. The main body 21 is cylindrical and forms the central portion. The shoulder 22 extends between the main body 21 and the inlet / outlet 23 in a direction orthogonal to the central axis C. The shoulder 22 has a circular opening in its central portion. The inlet / outlet 23 is continuous from the opening in the shoulder 22 and is cylindrical. The inlet / outlet 23 is formed parallel to the central axis C. The inlet / outlet 23 is the portion for fluid injection or discharge.

[0033] The insert 3, made of metal, is used for injecting or discharging fluid into or from the pressure vessel 1. The insert 3 has a flange 25 and a cylindrical portion 26. The flange 25 is annular and extends radially outward relative to the central axis C. The cylindrical portion 26 rises from the flange 25 and is cylindrical. The outer circumference of the cylindrical portion 26 increases in diameter towards the top, but it can also decrease in diameter or remain constant. The opening of the cylindrical portion 26 is designated as an "inner diameter opening 27".

[0034] The shoulder 22 of the inner liner 2 contacts the lower surface (end face) of the flange 25. Furthermore, the injection / discharge port 23 of the inner liner 2 contacts the inner surface of the inner diameter opening 27 within the entire circumferential direction and the direction of the central axis C. The inner liner 2 and the insert 3 are integrally molded during the manufacturing stage described later. That is, the inner liner 2 is integrally molded with the insert 3 by blow molding a preform, which is a molten resin, through the inner diameter opening 27.

[0035] The reinforcing layer 4 is a resin layer covering the outer side of the pressure vessel 1. More specifically, the reinforcing layer 4 covers a portion of the main body 21 and shoulder 22 of the inner liner 2, and a portion of the flange 25 and cylindrical portion 26 of the embedded component 3. The reinforcing layer 4 is formed, for example, by impregnating reinforcing fibers with an adhesive and then wrapping the fibers around and overlapping them with the inner layer. By providing the reinforcing layer 4, the strength of the pressure vessel 1 can be improved.

[0036] Next, regarding Figure 1 The manufacturing method of the pressure vessel 1 shown will be described. This manufacturing method is achieved by sequentially performing the following steps 1 to 4.

[0037] (1) First process

[0038] Figure 2 This is a longitudinal sectional view illustrating the first and second steps of the manufacturing method of the pressure vessel according to the first embodiment of this invention. Figure 2 As shown, in the first step, the upper and lower embedded parts 3 are held in a closed state using a pair of molds 31. The molds 31 and 31 are profiles used for blow molding the inner liner 2. The molds 31 and 31 can move in directions approaching or away from the central axis C. The inner surface of the mold 31 is the molding surface 32 used to mold the inner liner 2. The embedded parts 3 are held in the molds 31 and 31 with the cylindrical portions 26 facing outwards. Furthermore, while the embedded parts 3 are held by the molds 31, they can also be held by a lifting device or other holding devices.

[0039] (2) Second process

[0040] After the first step, the preform 41 is inserted into the inner diameter openings 27 of each embedded component 3 and into the hollow portion (cavity) of the mold 31. The preform 41 is molten resin and is cylindrical.

[0041] (3) Third process

[0042] After the second step, blow molding is performed, in which an air injection needle (not shown) is inserted into the inside of the preform 41 to supply air, thereby transferring the preform 41 onto the molding surface 32 of the mold 31, the lower surface (end face) of the flange portion 25 of the insert member 3, and the inner diameter opening portion 27 of the insert member 3. Figure 3 This is a longitudinal sectional view illustrating the third step of the manufacturing method of the pressure vessel according to this embodiment. Figure 3 As shown, air is supplied to the preform 41 to make it fit tightly against the forming surface 32, the lower surface (end face) of the flange portion 25 of the insert member 3, and the inner diameter opening 27 of the insert member 3. In this way, the inner liner 2 can be formed from the preform 41. Afterward, the air injection needle is removed, and after the formed inner liner 2 has cooled and hardened, the inner liner 2 is removed from the mold 31. In addition, the burrs exposed on the outside of the insert member 3 are removed.

[0043] (4) Step 4

[0044] After the third process, a reinforcing layer 5 is formed on the outer periphery of the inner liner 2 and the embedded component 3 (see reference). Figure 1 The reinforcing layer 5 is, for example, made by winding reinforcing fibers impregnated with adhesive around the inner liner 2.

[0045] According to the pressure vessel 1 and its manufacturing method described above, by inserting the preform 41 into the inner diameter opening 27, the injection port 23 of the blow-molded inner liner 2 can be tightly attached to the inner side of the inner diameter opening 27 with a uniform thickness. That is, since the preform 41 is located inside the inner diameter opening 27 of the embedded member 3, the preform 41 forming the injection port 23 will not be flattened by the molds 31 and 31 when the molds 31 and 31 are closed. Accordingly, no extrusion portion (a portion with uneven thickness due to extrusion) is formed in the injection port 23, thus suppressing the leakage of fluids such as hydrogen from the inner liner 2 and the embedded member 3. In addition, since no extrusion portion is formed, the injection port 23 can be formed with a uniform thickness, avoiding stress concentration in a part of the injection port 23, thereby improving strength.

[0046] [Second Implementation]

[0047] The embodiments described below also essentially have the structure of the pressure vessel 1 described in the first embodiment, and are manufactured using substantially the same manufacturing method. Therefore, in the following embodiments, descriptions of structures common to the previously described embodiments are omitted, and the same reference numerals are used for the same parts, etc. The second embodiment differs from the first embodiment in that it has a sealing surface on which a sealing member is provided.

[0048] Figure 4This is a longitudinal sectional view around the embedded part of a pressure vessel formed using a blow needle with a stepped portion, in the second embodiment of the present invention. Furthermore, the illustration of the reinforcing layer 5 is omitted. Figure 4 As shown, in the pressure vessel 1A of the second embodiment, a stepped portion 28 is formed at the top of the injection / discharge port 23. The injection / discharge port 23 is formed with a constant outer diameter, similar to that of the first embodiment. The stepped portion 28 is composed of a stepped bottom surface 28a and a stepped side surface 28b that rises from the outer edge of the stepped bottom surface 28a. A sealing member 55 (e.g., an O-ring) is installed on the stepped portion 28. The stepped bottom surface 28a is the sealing surface of the sealing member 55. By installing the sealing member 55 on the stepped portion 28, fluid leakage can be prevented, for example, when a valve (not shown) is connected to the embedded component 3.

[0049] Figure 5 This is a longitudinal sectional view around the embedded part in the third step of the pressure vessel manufacturing method according to the second embodiment of the present invention, after the air-blowing needle has been inserted into the inlet of the preform. Figure 5 As shown, the air-blowing needle 51 has a large-diameter portion 52, which is cylindrical and located at the base end, and a small-diameter portion 53, which is cylindrical and has a smaller diameter than the large-diameter portion 52. The outer diameter of the large-diameter portion 52 is larger than the inner diameter of the blank 41 and smaller than the outer diameter of the blank 41. In addition, the outer diameter of the large-diameter portion 52 is smaller than the inner diameter opening 27. The injection / discharge port 23 is formed by the outer peripheral surface of the air-blowing needle 51 and the inner diameter opening 27.

[0050] Additionally, a ring-shaped stepped portion 54 is formed by the large-diameter portion 52 and the small-diameter portion 53. The stepped portion 54 refers to the part of the sealing surface that is formed at the inlet portion of the portion that becomes the injection port 23 when the blank 41 is inserted from the outside (along the outside of the central axis C).

[0051] During blow molding in the third process, the blow needle 51 is inserted from the inside of the preform 41 and along the outside of the central axis C. This insertion position refers to the part of the preform 41 that becomes the injection / exhaust port 23. At this time, it is inserted such that the top of the large-diameter portion 52 is positioned lower than the end face of the cylindrical portion 26. Accordingly, the molding surface of the injection / exhaust port 23 is formed between the outer peripheral surface of the blow needle 51 and the inner diameter opening 27. That is, by… Figure 5 Blow molding is performed in the state shown, and the bottom surface 28a and the side surface 28b of the step are formed at the top of the injection port 23 through the step portion 54 while the injection port 23 is being formed.

[0052] In the prior art, when forming a sealing surface, the top of the injection port 23 or a portion of the embedded part 3 is cut after blow molding. However, when this method is used, there are problems such as increased processing time and unstable sealing surface, resulting in unstable sealing performance.

[0053] Regarding this, according to this embodiment, since the sealing surface (step bottom surface 28a) can be formed using the air-blowing needle 51, no additional work is required, and the sealing surface can be formed simultaneously with the blow molding process (third process). Therefore, the molding cycle can be shortened. Furthermore, since the step portion 54 of the air-blowing needle 51 is used for forming, the forming accuracy of the sealing surface can be improved, and the sealing performance can be stabilized.

[0054] [Third Implementation]

[0055] The third embodiment differs from the first embodiment in that it has a sealing surface on which a sealing member is provided, and the structure of the sealing surface is different from that of the second embodiment.

[0056] Figure 6 This is a longitudinal sectional view around the embedded part of a pressure vessel formed using a blow needle with a stepped portion, in the third embodiment of the present invention. Figure 6 As shown, the injection / discharge port 23 has a base 23a and an enlarged diameter portion 23b larger than the base 23a. A stepped portion 54 is formed by the base 23a and the enlarged diameter portion 23b. The stepped portion 54 is composed of a stepped bottom surface 54a and a stepped side surface 54b rising from the outer edge of the stepped bottom surface 54a. A sealing member 55 (e.g., an O-ring) is installed on the stepped portion 54. The stepped bottom surface 54a is the sealing surface of the sealing member 55.

[0057] A stepped portion 29 is formed on the inner side of the cylindrical portion 26 of the insert member 3. The stepped portion 29 is composed of a stepped bottom surface 29a and a stepped side surface 29b that rises from the outer edge of the stepped bottom surface 29a. The stepped portion 54 of the injection port 23 is in close contact with it in a manner that follows the shape of the stepped portion 29 of the insert member 3.

[0058] Figure 7 This is a longitudinal sectional view of the air-blowing needle and the embedded component according to the third embodiment of the present invention. Figure 8 This is a longitudinal sectional view of the embedded part after the air-blowing needle of the third embodiment of the present invention has been inserted into the inlet of the blank. (See image) Figure 7 As shown, the air-blowing needle 71 has a large-diameter portion 72, a medium-diameter portion 73, and a small-diameter portion 74. A first stepped portion 75 is formed by the large-diameter portion 72 and the medium-diameter portion 73. A second stepped portion 76 is formed by the medium-diameter portion 73 and the small-diameter portion 74. The outer diameter of the large-diameter portion 72 is the same as the outer diameter of the stepped side surface 29b of the stepped portion 29. The outer diameter of the medium-diameter portion 73 is the same as the inner diameter of the inner diameter opening 27. The height of the medium-diameter portion 73 is less than the height of the stepped side surface 29b of the stepped portion 29. The area surrounded by the outer peripheral surface of the insert member 3 and the air-blowing needle 71 is the portion for forming the injection port 23. Furthermore, the second stepped portion 76 is the portion of the stepped bottom surface 54a, which is formed into a sealing surface during the pressing of the preform 41.

[0059] like Figure 8As shown, during blow molding in the third step, the air-blowing needle 71 is inserted from the inside of the preform 41 and along the outside of the central axis C. At this time, it is inserted such that the top end of the large-diameter portion 72 is coplanar with the end face of the barrel portion 26. The injection / exhaust port 23 is formed through the area surrounded by the insert member 3 and the outer peripheral surface of the air-blowing needle 71. Additionally, the stepped portion 54, where the sealing member 55 is disposed, is formed simultaneously.

[0060] According to this embodiment, since the sealing surface (step bottom surface 54a) can be formed using the air-blowing needle 71, no additional work is required, and the sealing surface can be formed simultaneously with the blow molding process (third process). Therefore, the molding cycle can be shortened. Furthermore, since the sealing surface is formed using the first step portion 75 and the second step portion 76 of the air-blowing needle 71, the forming accuracy of the sealing surface can be improved, and the sealing performance can be stabilized. Additionally, according to the air-blowing needle 71, an enlarged diameter portion 23b can be formed at the injection / discharge port 23.

[0061] The embodiments of the present invention have been described above, but appropriate design changes can be made without departing from the spirit of the present invention.

[0062] [Explanation of reference numerals in the attached figures]

[0063] 1, 1A, 1B: Pressure vessel; 2: Inner liner; 3: Embedded component; 23: Injection / discharge port; 27: Inner diameter opening; 31: Mold; 41: Parison; 51, 71: Air injection needle.

Claims

1. A pressure vessel, wherein the inner liner and the embedded components are integrally formed by blow molding of the inner liner, characterized in that, The embedded component has an inner diameter opening along the central axis and is cylindrical. The inner liner is integrally formed with the embedded component by blow molding a preform through the inner diameter opening. The inner liner has a main body, an inlet / outlet, and a shoulder. The main body is cylindrical. The inlet / outlet is located inside the inner diameter opening. The shoulder connects the main body and the inlet / outlet. The inlet / outlet of the inner liner is formed along the entire axial length of the inner diameter opening.

2. The pressure vessel according to claim 1, characterized in that, The inner liner has an inlet / outlet port that contacts the opening of the inner diameter. During the blow molding process, an air-blowing needle with a stepped portion on the outer peripheral surface is inserted from the outside into the portion of the preform that becomes the injection port, thereby forming a sealing surface at the injection port.

3. A method for manufacturing a pressure vessel, characterized in that, It has three processes: process 1, process 2, and process 3. In the first step, a cylindrical insert member with an inner diameter opening formed along the central axis is maintained; In the second step, the blank is inserted into the inner diameter opening of the insert component and into the mold. In the third step, after the second step, air is supplied through an air-blowing needle to transfer the preform onto the molding surface of the mold and the inner diameter opening for blow molding. The pressure vessel's inner liner has a main body, an inlet / outlet, and a shoulder, wherein the main body is cylindrical; the inlet / outlet is located inside the inner diameter opening; and the shoulder connects the main body and the inlet / outlet. The inlet / outlet of the inner liner is formed along the entire axial length of the inner diameter opening.

4. The method for manufacturing a pressure vessel according to claim 3, characterized in that, In the third step, the air-blowing needle with a stepped portion on its outer peripheral surface is inserted from the outside into the part of the blank that contacts the inner diameter opening, which becomes the injection / discharge port, thereby forming a sealing surface at the injection / discharge port.

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