JP2017129155A - Pressure container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation of sealing performance.SOLUTION: A synthetic resin liner 10 has a trunk part 11, a dome part 12 extending from the axial end of the trunk part 11 to the radial inside, and a cylinder part 13 protruding from the inner peripheral edge of the dome part 12 to the axially outward side. A pressure container includes a cylindrical member 30 abutting on the inner peripheral face of the cylinder part 13. On the inner periphery of the cylinder part 13, a projecting hook part 20 is formed via which the cylindrical member 30 abuts thereon in the axial direction. A region of the cylinder part 13 on the base end side further than the hook part 20 is a thin portion 21 which is shaped so that the inner peripheral face is recessed relative to the hook part 20.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a pressure vessel.

  Patent Document 1 discloses a pressure vessel including a synthetic resin liner, a base, and a metal cylindrical member. The liner includes a body part, a dome part connected to an end part of the body part, and a cylindrical part protruding from the top part of the dome part. The base is coaxially attached to the outer periphery of the tube portion, and a seal ring for sealing a gap between the outer periphery of the tube portion is attached to the inner periphery of the base portion. The tubular member is attached to the tubular portion so as to correspond to the seal ring. The cylindrical member functions as a reinforcing means for preventing the contact area of the seal ring in the cylindrical portion from being displaced away from the inner periphery of the base. By the reinforcement of the tubular member, the sealing performance is improved by the seal ring.

JP 2013-137092 A

  When the tubular member is relatively displaced with respect to the tubular portion toward the axially projecting end side, there is a concern that the tubular member may not correspond to the seal ring. When the cylindrical member has a positional relationship that does not correspond to the seal ring, the reinforcing function by the cylindrical member is lost, and as a result, the sealing performance by the seal ring may be deteriorated.

  The present invention has been completed based on the above circumstances, and an object thereof is to prevent a decrease in sealing performance.

The pressure vessel of the present invention is
A synthetic resin liner,
A body part constituting the liner;
Constructing the liner, a dome portion projecting radially inward from the axial end of the trunk portion,
The cylindrical portion that constitutes the liner and protrudes outward in the axial direction from the inner peripheral edge of the dome,
A cylindrical member abutting on the inner peripheral surface of the cylindrical portion;
A projection-shaped hooking portion formed on the inner periphery of the cylindrical portion and contacting the cylindrical member in the axial direction;
A region of the cylindrical portion on the proximal end side with respect to the hooking portion is characterized in that it is a thin portion having an inner peripheral surface relatively recessed with respect to the hooking portion.

  By forming the hook portion, it is possible to prevent the cylindrical member from being displaced relative to the protruding end side with respect to the cylindrical member. Also, as the internal pressure of the pressure vessel increases, the cylindrical portion increases in the radial compression amount and becomes thin. However, since this compression amount is proportional to the thickness dimension before compression, the thin portion is thin. The change in thickness is relatively small. Thereby, since the shape of the inner peripheral surface of a cylinder part is stabilized, the inner periphery of a cylinder part and the outer periphery of a cylindrical member contact | abut reliably. Furthermore, since the thin portion has a shape in which the inner peripheral surface of the cylindrical portion is recessed, the maximum outer diameter and the minimum inner diameter of the cylindrical portion are smaller than when the thin portion has a shape in which the outer peripheral surface of the cylindrical portion is recessed. The dimensional difference is small. Therefore, the maximum outer diameter of the cylindrical portion can be kept small.

Sectional drawing of the pressure vessel of Example 1 Partial enlarged sectional view of FIG. Partial enlarged sectional view of FIG. Perspective view of cylindrical member

  The pressure vessel of the present invention constitutes the inner peripheral edge of the dome part, the shape of the cross section including the axis of the cylinder part is curved, and the curved part smoothly connected to the base end part of the cylinder part, It may be provided with an overhanging part which is formed in the cylindrical member and contacts the inner peripheral surface of the bending part. According to this configuration, even if the tubular member tries to be displaced toward the axially protruding end side with respect to the tubular portion, the overhanging portion is in contact with the curved portion, so that the displacement of the tubular member can be prevented. .

  The pressure vessel of the present invention comprises a base attached to the outer periphery of the cylindrical portion, and a seal ring attached between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the base, and the thin portion is A seal portion in contact with the seal ring may be included. According to this configuration, since the shape of the outer peripheral surface is stable in the thin portion even when the internal pressure of the pressure vessel increases, the sealing performance by the seal ring is also provided in the seal portion arranged in the thin portion formation region. Stabilize.

  In the pressure vessel of the present invention, the base is formed with a flange portion that contacts the outer periphery of the dome portion, the female screw portion is formed on the inner periphery of the base, and the outer periphery of the tubular member is A male screw portion that can be screwed into the female screw portion may be formed. According to this structure, the flange part of a nozzle | cap | die can be closely_contact | adhered to the outer peripheral surface of a dome part by screwing an internal thread part in an external thread part.

  In the pressure vessel of the present invention, the cylindrical member may be provided with a rotation preventing portion that regulates relative rotation between the liner and the cylindrical member by biting into the liner. According to this configuration, when the base is screwed into the cylindrical member, it is possible to avoid a situation in which the cylindrical portion is deformed so as to rotate with the base while rotating relative to the cylindrical member.

  The pressure vessel of the present invention may be configured such that the thin portion is changed so that the thickness thereof becomes thinner as the distance from the seal ring increases. According to this configuration, stress concentration when the internal pressure of the pressure vessel acts on the thin portion can be avoided.

<Example 1>
Embodiment 1 of the present invention will be described below with reference to FIGS. The pressure vessel of Example 1 includes a liner 10 made of synthetic resin, a cylindrical member 30, a base 40, a seal ring 47, and a fiber reinforced resin layer 50. The pressure vessel A is mounted on a fuel cell vehicle or a natural gas vehicle, and is used as a high-pressure hydrogen gas or natural gas filling vessel.

<Liner 10>
As shown in FIG. 1, the liner 10 has a cylindrical body 11 having a substantially constant diameter over its entire length, and a dome connected to one end (upper side in FIG. 1) in the axial direction of the cylindrical body 11. This is a single component including a portion 12, a cylindrical portion 13 that is continuous with the inner peripheral edge of the dome portion 12, and a closed end portion 14 that is continuous with the other end portion in the axial direction of the body portion 11. The interior of the liner 10 is a storage space 15 for storing fluid (hydrogen gas, natural gas, etc.). The liner 10 is formed into a predetermined shape by blow molding. As the material of the liner 10, a mixed resin of high density polyethylene (HDPE) and ethylene / vinyl alcohol copolymer resin (EVOH), polyamide resin, polypropylene resin, or the like is used.

  The dome portion 12 has a form projecting concentrically with the trunk portion 11 from the upper end of the trunk portion 11 in FIG. The dome 12 is a flat shoulder 16 that is substantially perpendicular to the axis A of the trunk 11 (see FIG. 2), and a spherical joint that connects the outer periphery of the shoulder 16 and the end of the trunk 11. Part 17 and a curved part 18 constituting the inner peripheral edge of dome part 12. As shown in FIG. 2, the shape of the curved portion 18 in the cross section including the axis A of the body portion 11 is a substantially quarter arc shape (that is, a curved shape). In this cross-sectional shape, the outer peripheral side end portion of the curved portion 18 is connected to the inner peripheral edge portion of the shoulder portion 16 in a tangential manner. The curved portion 18 is curved so that the inner peripheral side gradually faces upward (the outer surface side of the pressure vessel).

  The cylinder portion 13 is formed in a cylindrical shape concentric with the body portion 11 and protrudes toward the outer surface side of the liner 10. The axis A of the cylinder part 13 and the axis A of the trunk part 11 coincide. The base end portion (the lower end portion in FIGS. 1 to 3) of the cylindrical portion 13 is connected to the inner peripheral edge portion of the bending portion 18 in a tangential manner. Of the cylindrical portion 13, a substantially central portion in the axial direction functions as a seal portion 19, and an outer peripheral surface of the seal portion 19 is a seal surface that comes into contact with a seal ring 47 described later. On the inner periphery of the protruding end portion (upper end portion in FIGS. 1 to 3) of the cylindrical portion 13, a hooking portion 20 is formed over the entire periphery. The thickness of the hook portion 20 is substantially the same as that of the shoulder portion 16, the connecting portion 17, and the trunk portion 11. Hereinafter, this thickness is referred to as a “reference thickness” of the liner 10. The thick part 22 of the area | region (shoulder part 16 and the connection part 17) of the outer peripheral side rather than the curved part 18 among the dome parts 12 is also reference | standard thickness.

  A region on the proximal end side of the hook portion 20 in the cylindrical portion 13 and a region on the inner peripheral side connected to the cylindrical portion 13 in the bending portion 18 are thin portions 21 over the entire circumference. A boundary portion between the cylindrical portion 13 and the curved portion 18 is included in the thin portion 21. Further, the seal portion 19 with which the seal ring 47 is in close contact is also included in the range of the thin portion 21. The thickness of the thin portion 21 is thinner than the reference thickness. The thin portion 21 has a configuration in which the inner peripheral surface of the curved portion 18 and the inner peripheral surface of the tubular portion 13 are recessed relative to the hook portion 20. Due to the recessed form of the thin portion 21, the hook portion 20 protrudes relatively to the inner peripheral surface of the thin portion 21. Moreover, the outer peripheral surface of the cylinder part 13 and the outer peripheral surface of the curved part 18 are smoothly continuing in a tangent form.

  The thickness of the thin portion 21 is not uniform over the entire region. Specifically, the region of the thin portion 21 that forms the cylindrical portion 13 (from the lower end of the hook portion 20 to the boundary with the curved portion 18). The thickness Ta of the region to reach is substantially constant throughout the entire region. Further, regarding the region constituting the bending portion 18 in the thin portion 21, the thickness Ta of the inner peripheral end (boundary with the tubular portion 13) of the bending portion 18 is the largest, and the thickness Tb of the outer peripheral end of the thin portion 21. Is the smallest. That is, in the thin portion 21, the region constituting the curved portion 18 becomes thinner as the distance from the seal ring 47 increases.

<Cylindrical member 30>
The cylindrical member 30 is made of metal and has a cylindrical shape as a whole. The tubular member 30 is attached in contact with the inner periphery of the tubular portion 13 and the bending portion 18. The upper end portion of the cylindrical member 30 is a receiving portion 31 whose upper surface is substantially perpendicular to the axis A of the cylindrical portion 13. A male screw portion 32 is formed on the outer periphery of the upper end portion of the cylindrical member 30. The area | region adjacent to the downward direction (base end side in the cylinder part 13) of the external thread part 32 among the outer periphery of the cylindrical member 30 becomes a recessed form. The lower end portion of the recessed portion is a stepped locking portion 33.

  At the lower end portion of the cylindrical member 30, an overhang portion 34 having a shape concentrically expanding downward is formed. The overhanging portion 34 is in contact with the inner surface of the curved portion 18 where the thin portion 21 is formed. A plurality of groove portions 35 extending radially inward from the outer peripheral edge of the overhang portion 34 are formed at intervals in the circumferential direction. A plurality of anti-rotation portions 36 that are divided in the circumferential direction by groove portions 35 are formed in the overhang portion 34. In addition, a first valve thread portion 37 for fixing the valve 38 (see FIG. 1) is formed on the inner periphery of the cylindrical member 30.

<Molding process of liner 10>
The tubular member 30 is integrated with the liner 10 in the process of blow molding the liner 10. In the molding process of the liner 10, a substantially cylindrical parison (not shown) is pushed downward from a blow molding machine (not shown) with its axis line directed upward and downward, and the cylindrical member 30 is held in the extruded parison. A rod (not shown) is accommodated. And a pair of metal mold | die (illustration omitted) is clamped and pressurized air is supplied in a parison through a rod. Then, the parison is pressed against the inner surface of the cavity of the mold, and the body portion 11 and the dome portion 12 are formed.

  Further, a part of the parison is pressed against the outer periphery of the cylindrical member 30 by a mold, whereby the entire cylindrical part 13 and a part of the curved part 18 are molded. At this time, the thin portion 21 is formed thin with the entire region thereof being in close contact with the outer peripheral surface of the tubular member 30, and the hook portion 20 is also formed. The molded hook portion 20 is in close contact with the locking portion 33 of the tubular member 30 in a form in which even the protruding end side is locked.

  Further, when a part of the parison is pressed against the outer periphery of the cylindrical member 30 by the mold, a part of the parison protrudes from the inner peripheral surface of the curved portion 18 and enters the groove portion 35. A portion of the parison that has entered the groove portion 35 is in a state in which relative displacement in the circumferential direction is restricted with respect to the rotation preventing portion 36. Thereby, the cylindrical member 30 is integrated with the liner 10 in a state of being in close contact with the entire inner peripheral surface area of the cylindrical portion 13 and a part of the inner peripheral surface of the bending portion 18.

  Further, since the thin portion 21 including the seal portion 19 is sandwiched in the radial direction between the mold and the cylindrical member 30, the thickness dimension is highly accurate. In addition, since the shrinkage when the synthetic resin liner 10 is sinked in the cooling process after molding is proportional to the thickness before shrinkage, the shrinkage in the cooling process of the thin portion 21 can be kept small. This is also a factor that improves the dimensional accuracy of the seal portion 19. If the parison is cured after molding with the above mold, the molding process of the liner 10 is completed.

<Base 40>
The base 40 has a cylindrical main body portion 41 penetrating in the axial direction, and a flange portion projecting radially outward from a base end portion (lower end portion in FIGS. 1 to 3) of both end portions in the axial direction of the main body portion 41. 42 is a single part. A valve second screw portion 43 for attaching the valve 38 is formed at the distal end portion of the inner periphery of the main body portion 41. The base 40 is attached to the liner 10 in a form that covers the entire outer peripheral surface of the cylindrical portion 13 with almost no gap and covers the outer peripheral surfaces of the shoulder portion 16 and the curved portion 18 of the dome portion 12 with almost no gap. Yes.

  A contact portion 44 is formed on the inner periphery of the main body portion 41 of the base 40, which has a stepped shape and whose lower surface is substantially perpendicular to the axis A of the cylindrical portion 13. A female screw portion 45 is formed in a region adjacent to the lower portion of the contact portion 44 in the inner periphery of the main body portion 41. In addition, a seal groove 46 is formed in the base end portion of the main body 41 so as to have a concave inner peripheral surface. A seal ring 47 is attached to the seal groove 46.

  The base 40 is assembled to the cylindrical member 30 and the liner 10 by screwing the female screw portion 45 into the male screw portion 32 of the cylindrical member 30. As the female screw portion 45 is screwed into the male screw portion 32, the base 40 is displaced in the axial direction relative to the cylindrical member 30 toward the proximal end side. At this time, a pressing force toward the proximal end acts on the cylindrical portion 13 due to friction with the inner peripheral surface of the base 40, but the hooking portion 20 at the protruding end of the cylindrical portion 13 is Since it latches with respect to the latching | locking part 33 of the shaped member 30 from the protrusion end side, there is no possibility that the deformation | transformation which the cylinder part 13 may displace to a base end side will arise.

  Further, when screwing the cap 40 into the cylindrical member 30, the cylindrical member 30 is held in a rotation restricted state by being fixed to the rod. On the other hand, the rotational force of the base 40 acts on the outer periphery of the cylindrical portion 13 due to friction with the seal ring 47. Therefore, there is a concern that the tubular portion 13 may be deformed so as to rotate with the base 40 while rotating relative to the tubular member 30. However, since the cylindrical portion 13 and the cylindrical member 30 are restricted from relative displacement in the circumferential direction by the locking action of the rotation preventing portion 36, there is no possibility that the cylinder portion 13 is rotated.

  When the base 40 reaches the normal assembly position, the contact portion 44 of the base 40 contacts the receiving portion 31 of the tubular member 30 in the axial direction. Due to this contact, further screwing of the base 40 is restricted, and the base 40 is positioned with respect to the tubular member 30 and the liner 10 in the axial direction. In a state where the base 40 is correctly assembled to the tubular member 30 and the liner 10, the seal ring 47 elastically contacts the outer peripheral surface of the seal portion 19. By this seal ring 47, the gap between the outer peripheral surface of the cylindrical portion 13 and the inner peripheral surface of the base 40 is sealed in an airtight manner. Further, the inner surface of the flange portion 42 comes into contact with the outer surface of the shoulder portion 16 and the bending portion 18.

<Fiber reinforced resin layer 50>
The fiber reinforced resin layer 50 is made of carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic, or the like. The fiber reinforced resin layer 50 is formed so as to cover the entire outer peripheral region of the body portion 11, the connecting portion 17 on the outer peripheral side of the base 40, the outer peripheral surface of the closed end portion 14, and the outer peripheral surface of the base 40. ing. The fiber reinforced resin layer 50 is obtained by impregnating a liquid thermosetting resin into a fiber bundle (not shown) on the outer surface of the liner 10 and the base 40 rotating around the axis A of the body 11 by the filament winding method. It is formed by wrapping a thing or a prepreg fiber in which a thermosetting resin impregnated in a fiber bundle is semi-cured. The fiber bundle is a bundle of thread-like fibers made of carbon fiber, glass fiber, Kepla fiber, or the like.

<Operation and Effect of Example>
The pressure vessel of the present embodiment includes a synthetic resin liner 10. The liner 10 includes a body portion 11, a dome portion 12 projecting radially inward from an axial end portion of the body portion 11, and a cylindrical portion 13 projecting outward in the axial direction from the inner peripheral edge portion of the dome portion 12. Configured. The dome portion 12 includes a curved portion 18 that constitutes an inner peripheral edge portion thereof. The curved portion 18 has a curved cross section including the axis A of the cylindrical portion 13, and is smoothly connected to the proximal end portion of the cylindrical portion 13. Further, the pressure vessel includes a base 40 attached to the outer periphery of the tube part 13 and a seal ring 47 that seals a gap between the inner peripheral surface of the base 40 and the outer peripheral surface of the tube part 13. The region of the cylindrical portion 13 from the seal portion 19 to which the seal ring 47 is in close contact to the vicinity of the boundary with the curved portion 18 is thicker than the thick portion 22 on the outer peripheral side of the curved portion 18 in the dome portion 12. A thin thin portion 21 is formed.

  The pressure (internal pressure) of the fluid stored in the storage space 15 of the pressure vessel also acts on the interface between the outer peripheral surface of the cylindrical member 30 and the inner peripheral surface of the liner 10. Therefore, a radially outward pressing force acts on the inner peripheral surfaces of the cylindrical portion 13 and the bending portion 18, and the cylindrical portion 13 and the bending portion 18 are compressed in the radial direction by this pressing force. As the internal pressure increases, the amount of compression increases and the tube portion 13 and the curved portion 18 become thinner. This amount of compression is proportional to the wall thickness before compression. Therefore, when a thick region exists in the vicinity of the seal ring 47, the influence of the compression of the thick region may reach the seal portion 19 that contacts the seal ring 47. If it becomes like this, the thickness of the seal part 19 is insufficient, and there is a concern that the seal performance will be lowered.

  However, in the pressure vessel of the present embodiment, the seal portion 19 is included in the thin portion 21 having a relatively small compression amount, and the seal ring 47 of the cylindrical portion 13 is in close contact with the formation region of the thin portion 21. The range from the portion 19 to the vicinity of the boundary with the curved portion 18 was set. Thereby, since the thick part 22 of the dome part 12 exists in the position far from the seal ring 47, there is no possibility that the influence of the compression of the thick part 22 may reach the seal part 19. Moreover, since the thin portion 21 including the seal portion 19 has a small amount of compression due to the increase in internal pressure, the shape of the outer peripheral surface and the inner peripheral surface of the seal portion 19 is stable even when the internal pressure increases. Therefore, the pressure vessel of this embodiment has high sealing performance.

  In addition to the liner 10, the pressure vessel of the present embodiment includes a metallic cylindrical member 30 that abuts at least the seal portion 19 on the inner peripheral surface of the cylindrical portion 13. A projecting hooking portion 20 is formed on the inner periphery of the tubular portion 13 so as to abut the tubular member 30 in the axial direction. The hook portion 20 is formed on the protruding end side of the inner periphery of the cylindrical portion 13 with respect to the seal portion 19, and protrudes relatively to the inner peripheral surface of the thin portion 21. In other words, the region on the proximal end side of the hook portion 20 in the cylindrical portion 13 is a thin portion 21 having an inner peripheral surface relatively recessed with respect to the hook portion 20. The thickness of the thin portion 21 is thinner than the protruding end portion of the cylindrical portion 13 where the hook portion 20 is formed.

  The technical significance of this configuration is as follows. Since the metallic cylindrical member 30 that abuts at least the seal portion 19 on the inner periphery of the cylindrical portion 13 is provided, and the cylindrical member 30 reliably prevents the cylindrical portion 13 from being displaced toward the inner peripheral side. Sealing performance is improved. Further, by forming the hooking portion 20, the cylindrical member 30 is prevented from being displaced relative to the protruding end side with respect to the cylindrical member 30. Thereby, since the positional relationship of the axial direction of the cylindrical member 30 and the seal ring 47 becomes appropriate, it is excellent in sealing performance.

  Further, as described above, in the thin portion 21, the change in the thickness due to the increase in internal pressure is suppressed to be relatively small, so that the shape of the inner peripheral surface of the cylindrical portion 13 is stabilized. As a result, the inner peripheral surface of the cylindrical portion 13 reliably abuts on the outer peripheral surface of the cylindrical member 30, so that the outer peripheral shape and outer diameter of the seal portion 19 are also stabilized, and the sealing performance by the seal ring 47 is improved. Furthermore, since the thin portion 21 has a shape in which the inner peripheral surface of the cylindrical portion 13 is recessed, the maximum outer portion of the cylindrical portion 13 is smaller than when the thin portion 21 has a shape in which the outer peripheral surface of the cylindrical portion 13 is recessed. The dimensional difference between the diameter and the minimum inner diameter is small. Therefore, the maximum outer diameter of the cylinder part 13 can be kept small. In addition, since the thin portion 21 has a shape that is changed so that the thickness thereof becomes farther away from the seal ring 47, stress concentration when the internal pressure of the pressure vessel acts on the thin portion 21 can be avoided.

  Moreover, the dome part 12 has the curved part 18 which comprises the inner peripheral part. The curved portion 18 has a curved cross section including the axis A of the cylindrical portion 13, and is smoothly connected to the proximal end portion of the cylindrical portion 13. At least a part of the curved portion 18 is included in the range where the thin portion 21 is formed. Further, the tubular member 30 is formed with an overhanging portion 34 that comes into contact with the formation region of the thin portion 21 on the inner peripheral surface of the bending portion 18. According to this configuration, when the base 40 is screwed into the tubular member 30, the protruding portion 34 is not bent toward the curved portion 18 even if the tubular member 30 tends to be displaced toward the axially protruding end side with respect to the tubular portion 13. Therefore, the displacement of the cylindrical member 30 can be prevented.

  In addition to the liner 10, the pressure vessel according to the present embodiment includes a base 40 coaxially assembled to the outer periphery of the cylindrical portion 13, an inner peripheral surface of the base 40 and the cylindrical portion attached to the inner periphery of the base 40. 13 is provided with a seal ring 47 that seals a gap with the outer peripheral surface of 13. A female screw portion 45 and a contact portion 44 are formed on the inner periphery of the base 40. The pressure vessel further includes a metallic cylindrical member 30 fixed to the inner peripheral surface of the cylindrical portion 13. The cylindrical member 30 is formed with a male screw portion 32 that can be screwed into the female screw portion 45. Similarly, the tubular member 30 is formed with a receiving portion 31 that restricts the base 40 from being displaced relative to the tubular member 30 in the axial direction by contacting the contact portion 44.

  According to this configuration, the base 40 is assembled to the outer periphery of the cylindrical portion 13 by screwing the female screw portion 45 into the male screw portion 32. Further, when the base 40 reaches the normal assembly position, the contact portion 44 contacts the receiving portion 31, the base 40 is positioned in the axial direction with respect to the tubular member 30, and the tubular member 30 and the seal ring 47. Is an appropriate positional relationship corresponding to the radial direction. Therefore, it is possible to prevent a decrease in sealing performance due to the positional displacement of the seal ring 47 with respect to the cylindrical member 30.

  Further, the cylindrical member 30 is formed with a rotation preventing portion 36 that regulates relative rotation between the liner 10 and the cylindrical member 30 by biting into the liner 10. According to this configuration, when the base 40 is screwed into the tubular member 30, it is possible to avoid a situation in which the tubular portion 13 is deformed so as to rotate with the base 40 while rotating relative to the tubular member 30. . In addition, the flange 40 is formed on the base 40 so as to contact the outer periphery of the dome portion 12. 12 can be brought into close contact with the outer peripheral surface.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, the tubular member is formed with the overhanging portion that comes into contact with the formation region of the thin portion of the curved portion. However, the tubular member may have no overhanging portion.
(2) In the above-described embodiment, the thin portion forming region includes a part of the curved portion. However, the thin portion forming region may not include the curved portion at all, and may include the entire curved portion. Also good.
(3) In the said Example, although the flange part closely_contact | adhered to the outer peripheral surface of a dome part was formed in the nozzle | cap | die, the form which does not form a flange part may be sufficient as a nozzle | cap | die.
(4) In the above embodiment, the base and the cylindrical member are fixed by screwing, but the base and the cylindrical member may be in non-contact with each other.
(5) In the above embodiment, the anti-rotation portion is formed in the overhang portion, but the anti-rotation portion may be formed in a portion other than the overhang portion of the tubular member.
(6) In the above-described embodiment, the anti-rotation portion is formed on the cylindrical member. However, the cylindrical member may have a form that does not have the anti-rotation portion.
(7) In the above-described embodiment, the thin portion has a shape that is changed so that the thickness is reduced as the distance from the seal ring is increased. The shape may be sufficient, and may be constant irrespective of the distance from the seal ring.
(8) In the above embodiment, the seal ring is brought into contact with the thin part, but the seal ring may be brought into contact with a region other than the thin part.

A ... Axis of cylinder part 10 ... Liner 11 ... Body part 12 ... Dome part 13 ... Cylinder part 18 ... Curved part 19 ... Seal part 20 ... Hook part 21 ... Thin part 22 ... Thick part 30 ... Cylindrical member 32 ... Male thread part 34 ... Overhang part 36 ... Anti-rotation part 40 ... Base 42 ... Flange part 45 ... Female thread part 47 ... Seal ring

Claims (6)

A synthetic resin liner,
A body part constituting the liner;
Constructing the liner, a dome portion projecting radially inward from the axial end of the trunk portion,
The cylindrical portion that constitutes the liner and protrudes outward in the axial direction from the inner peripheral edge of the dome,
A cylindrical member abutting on the inner peripheral surface of the cylindrical portion;
A projection-shaped hooking portion formed on the inner periphery of the cylindrical portion and contacting the cylindrical member in the axial direction;
The pressure vessel characterized in that a region of the cylindrical portion closer to the proximal end than the hooking portion is a thin portion having an inner peripheral surface relatively recessed with respect to the hooking portion. . The inner periphery of the dome portion is configured, the shape of the cross section including the axis of the tube portion is curved, and a curved portion smoothly connected to the base end portion of the tube portion;
The pressure vessel according to claim 1, further comprising an overhang portion formed on the tubular member and in contact with an inner peripheral surface of the curved portion. A base attached to the outer periphery of the cylindrical portion;
A seal ring attached between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the base;
The pressure vessel according to claim 1, wherein the thin portion includes a seal portion that contacts the seal ring. The base is formed with a flange portion that contacts the outer periphery of the dome portion,
An internal thread is formed on the inner periphery of the base,
The pressure vessel according to claim 3, wherein a male screw portion that can be screwed into the female screw portion is formed on an outer periphery of the cylindrical member.   The pressure vessel according to claim 4, wherein the cylindrical member is formed with an anti-rotation portion that restricts relative rotation between the liner and the cylindrical member by biting into the liner.   The pressure vessel according to any one of claims 3 to 5, wherein the thin portion has a shape that is changed such that the thickness of the thin portion decreases as the distance from the seal ring increases.

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