JP7586046B2 - Pressure vessels - Google Patents

Description

This disclosure relates to a pressure vessel.

Inventions relating to hydrogen tanks have been known for some time. The hydrogen tank described in Patent Document 1 below comprises a liner section, a fiber-reinforced resin layer, and a resin layer (same document, abstract, etc.). The liner section constitutes the container body, and is capable of storing hydrogen inside. The fiber-reinforced resin layer is disposed on the outer periphery of the liner section, and is composed of reinforcing fibers and a thermosetting resin. The resin layer is disposed on the outer periphery of the fiber-reinforced resin layer, has a plurality of through holes formed in its surface that reach the fiber-reinforced resin layer, and is composed of a thermosetting resin.

The pressure vessel described in Patent Document 2 below comprises a liner, a reinforcing layer, and a mouthpiece (same document, abstract, etc.). The liner is filled with gas. The reinforcing layer is formed using fiber-reinforced resin in contact with the outer surface of the liner, covering the liner from the outside. The mouthpiece is attached to the liner. The mouthpiece has a locking claw that extends along the internal fibers of the fiber-reinforced resin that constitutes the reinforcing layer. The mouthpiece is attached to the liner in a state where the locking claw deforms the fiber-reinforced resin that constitutes the reinforcing layer.

The fiber-reinforced resin layer (reinforcement layer) of the above-mentioned conventional hydrogen tanks and pressure vessels is formed, for example, by the resin transfer molding (RTM) method (Patent Document 1, paragraph 0014, etc.). More specifically, the fiber-reinforced resin layer is molded by the RTM method in the following procedure. First, a fiber layer is formed by winding fiber around the outside of the liner. Next, the liner with the fiber layer formed on the outside is placed in a mold, and uncured curable resin is injected into the mold. After that, the uncured curable resin impregnated in the outer fiber layer of the liner is cured, and a fiber-reinforced resin layer is formed on the outside of the liner.

JP 2020-118288 A JP 2020-112189 A

When molding a fiber-reinforced resin layer using the RTM method, internal pressure may be applied to the liner to prevent deformation of the liner and fiber layer due to the pressure of the uncured curable resin injected into the mold. In this case, the diameter of the cylindrical liner may expand due to the pressure difference between the pressure of the resin injected into the mold and the internal pressure of the liner, and the fibers that make up the fiber layer may be pulled from the ends in the axial direction of the liner to the center. If the fibers that make up the outer fiber layer of the liner are pulled from the ends in the axial direction of the liner to the center in this way, the fibers that are wound by applying tension to the outside of the liner may relax, and the pressure resistance of the hydrogen tank or pressure vessel may decrease.

This disclosure provides a pressure vessel that can improve pressure resistance by preventing relaxation of the fibers wound around the liner when forming a fiber-reinforced resin layer using the RTM method.

The pressure vessel according to one aspect of the present disclosure is a pressure vessel comprising a liner that forms a space for accommodating a gas, and a fiber-reinforced resin layer that covers the outer surface of the liner, and is characterized in that it comprises a tubular member embedded in the liner at least in a portion of a cylindrical neck portion provided at an axial end of the pressure vessel, and the tubular member has a protrusion that protrudes from the outer surface of the liner and is embedded in the fiber-reinforced resin layer.

In the pressure vessel of the above aspect, the protrusion may be provided at the axial end of the tubular member located on the tip side of the neck portion.

In the pressure vessel of the above aspect, the protrusion may be provided around the entire circumference of the tubular member, and the diameter may increase as it approaches the tip of the neck portion.

In the pressure vessel of the above aspect, the tubular member may have a plurality of through holes spaced apart in the circumferential direction, and the liner may have a plurality of engagement portions filled in the plurality of through holes of the tubular member.

In the pressure vessel of the above aspect, the plurality of through holes and the plurality of locking portions may be provided at both ends of the tubular member in the axial direction.

In the above aspect, the pressure vessel may have a cylindrical body portion provided in the middle in the axial direction and having a larger diameter than the neck portion, and a shoulder portion provided between the body portion and the neck portion and having a gradually reduced diameter toward the end in the axial direction, and the tubular member may have a straight pipe portion embedded in the liner at the neck portion, and an expanded diameter portion embedded in the liner at the shoulder portion and having a larger diameter the further away from the straight pipe portion in the axial direction.

According to the above aspect of the present disclosure, it is possible to provide a pressure vessel that can prevent the fibers wound around the liner from relaxing when the fiber-reinforced resin layer is molded by the RTM method, thereby improving the pressure resistance.

FIG. 1 is a cross-sectional view of one embodiment of a pressure vessel according to the present disclosure. FIG. 2 is an enlarged cross-sectional view of the neck portion of the pressure vessel shown in FIG. 1 .

Below, an embodiment of a pressure vessel according to the present disclosure will be described with reference to the drawings.

Figure 1 is a cross-sectional view showing one embodiment of a pressure vessel according to the present disclosure. The pressure vessel 100 of this embodiment is, for example, a tank mounted on a fuel cell vehicle or a hydrogen vehicle and filled with high-pressure hydrogen gas. The pressure vessel 100 includes, for example, a vessel body 110, a valve 120, a sealing member 130, a tubular member 140, and a nozzle 150.

The container body 110 comprises a liner 111 that forms a space for storing gas, and a fiber-reinforced resin layer 112 that covers the outer surface of the liner 111. The container body 110 also comprises, for example, a neck portion 113, a shoulder portion 114, a body portion 115, a bottom portion 116, and an opening portion 117. That is, the pressure vessel 100 comprises, for example, the liner 111 and the fiber-reinforced resin layer 112, and has the neck portion 113, the shoulder portion 114, the body portion 115, the bottom portion 116, and an opening portion 117.

The liner 111 is an inner container made of, for example, a synthetic resin with gas barrier properties. Examples of materials that can be used for the liner 111 include polyamide, polyethylene, ethylene-vinyl alcohol copolymer resin (EVOH), polyester, and epoxy. The fiber-reinforced resin layer 112 covers the outer surface of the liner 111 that contains the gas, and functions as a reinforcing layer that ensures the strength of the container body 110.

The fiber-reinforced resin layer 112 is formed, for example, by a resin transfer molding (RTM) method. More specifically, the fiber-reinforced resin layer 112 is molded, for example, by the following procedure using the RTM method. First, a fiber bundle is wound around the outside of the liner 111 to form a fiber layer. Next, the liner 111 with the fiber layer formed on the outside is placed in a mold, and uncured curable resin is injected into the mold while internal pressure is applied to the liner 111. After that, the uncured curable resin impregnated in the outer fiber layer of the liner 111 is cured to form the fiber-reinforced resin layer 112 on the outside of the liner 111.

Here, the fiber bundle wound around the outside of the liner 111 to form the fiber-reinforced resin layer 112 is, for example, a bundle of reinforcing fibers such as glass fiber, aramid fiber, boron fiber, or carbon fiber, and is, for example, a strip-shaped fiber bundle with a width of about 1 mm to 10 mm. As the curable resin that is injected into the mold and impregnated into the outer fiber layer of the liner 111 to form the fiber-reinforced resin layer 112, for example, a thermosetting resin such as a phenol resin, a melamine resin, a urea resin, or an epoxy resin can be used. In addition, a thermoplastic resin such as polyether ether ketone, polyphenylene sulfide, polyacrylic ester, polyimide, or polyamide can also be used as the curable resin.

The neck portion 113 of the pressure vessel 100 is a cylindrical portion of the vessel body 110 provided at the end of the axial direction Da parallel to the central axis A of the pressure vessel 100. The pressure vessel 100 has a minimum diameter at the neck portion 113, for example. The neck portion 113 has an opening 117 at its tip, and a cylindrical nozzle 150 is fixed to the outer circumferential surface of the tip. The valve 120 is fixed to the opening 117 of the vessel body 110 of the pressure vessel 100 by screwing a male thread provided on the outer circumferential surface of this nozzle 150 into a female thread provided on the inner circumferential surface of the attachment portion 123 of the valve 120.

The body 115 of the pressure vessel 100 is a cylindrical portion of the vessel body 110 that is provided in the middle in the axial direction Da parallel to the central axis A of the pressure vessel 100 and has a larger diameter than the neck portion 113. The shoulder portion 114 of the pressure vessel 100 is a dome-shaped portion of the vessel body 110 that is provided between the body 115 and the neck portion 113 and has a gradually reduced diameter toward the end of the axial direction Da of the pressure vessel 100 that has an opening 117. The bottom 116 of the pressure vessel 100 is a dome-shaped portion of the vessel body 110 that is provided at the end of the body 115 opposite the neck portion 113 in the axial direction Da of the pressure vessel 100.

The valve 120 is, for example, a metal member, and has an insertion portion 121, a gas passage 122, and an attachment portion 123. The insertion portion 121 is a cylindrical portion that is inserted into the neck portion 113 from the opening 117. The outer peripheral surface of the insertion portion 121 is provided with, for example, an annular groove in the circumferential direction in which the seal member 130 is disposed. The gas passage 122 is provided in the insertion portion 121, and connects the space that contains the gas inside the liner 111 to a manifold or the like outside the pressure vessel 100.

The mounting portion 123 of the valve 120 has a cylindrical concave shape with a bottom that is attached around the tip of the neck portion 113. To attach the valve 120 to the tip of the neck portion 113 of the container body 110, the female thread provided on the inner peripheral surface of the mounting portion 123 is screwed into the male thread provided on the outer peripheral surface of the nozzle 150. As a result, the insertion portion 121 extending from the center of the bottom of the mounting portion 123 in the axial direction Da of the pressure vessel 100 is inserted into the inside of the neck portion 113 from the opening 117, and the valve 120 is fixed to the tip of the neck portion 113 of the container body 110 via the nozzle 150.

The seal member 130 is, for example, an O-ring made of elastic resin, and is compressed between the outer peripheral surface of the insertion portion 121 of the valve 120 and the inner peripheral surface of the liner 111 of the neck portion 113 to hermetically seal the space for containing the gas inside the liner 111. The seal member 130 is, for example, disposed in a groove formed on the outer peripheral surface of the insertion portion 121 of the valve 120, as described above.

The tubular member 140 is, for example, a metallic member embedded in the liner 111 at least in a portion of the cylindrical neck portion 113 provided at the end of the axial direction Da of the pressure vessel 100. The tubular member 140 prevents the diameter of the neck portion 113 from expanding when the internal pressure of the pressure vessel 100 increases, thereby ensuring a seal between the liner 111 and the seal member 130. The tubular member 140, which is a characteristic part of the pressure vessel 100 of this embodiment, will be described in detail with reference to FIG. 2.

Figure 2 is an enlarged cross-sectional view of the neck portion 113 of the pressure vessel 100 shown in Figure 1. As described above, the tubular member 140 is embedded in the liner 111 at least in a portion of the cylindrical neck portion 113 provided at the end of the axial direction Da parallel to the central axis A of the pressure vessel 100. The tubular member 140 has a protrusion 141 that protrudes from the outer surface of the liner 111 and is embedded in the fiber-reinforced resin layer 112.

The protrusion 141 is provided, for example, at the end of the tubular member 140 in the axial direction Da, which is parallel to the central axis A of the pressure vessel 100, located on the tip side of the neck portion 113, which is the end of the pressure vessel 100 in the axial direction Da. Note that the protrusion 141 may be provided, for example, in the intermediate portion between the two ends of the tubular member 140 in the axial direction Da of the pressure vessel 100, or at the end of the tubular member 140 opposite the tip of the neck portion 113 having the opening 117.

The protrusion 141 is provided, for example, continuously in the circumferential direction around the entire circumference of the tubular member 140, and the diameter increases as it approaches the tip of the neck portion 113, which is one end of the axial direction Da of the pressure vessel 100. More specifically, the protrusion 141 protrudes radially outward toward the tip of the neck portion 113, which is the end of the axial direction Da, in a protruding direction that is inclined at a predetermined angle θ with respect to the axial direction Da that is parallel to the central axis A of the pressure vessel 100.

Here, the angle θ of the protrusion 141 with respect to the axial direction Da is, for example, 90 degrees or less, more specifically, 45 degrees or less. Note that the protrusion 141 may be provided, for example, partially in the circumferential direction of the tubular member 140. The tubular member 140 has, for example, a cylindrical shape whose diameter increases as it approaches both ends of the axial direction Da of the pressure vessel 100.

More specifically, the tubular member 140 has, for example, a protruding portion 141, a straight pipe portion 142, and an enlarged diameter portion 143 from the tip side of the neck portion 113 in the axial direction Da of the pressure vessel 100. As described above, the diameter of the protruding portion 141 increases as it approaches the tip of the neck portion 113. The protruding height H of the protruding portion 141 protruding from the outer surface of the liner 111 is, for example, in the range of about 0.5 to 2 times the thickness of the tubular member 140.

The straight pipe section 142 is a straight pipe section embedded in the liner 111 at the neck section 113 of the pressure vessel 100. In other words, the diameter of the straight pipe section 142 is constant and does not change depending on the position in the axial direction Da of the pressure vessel 100, and the outer and inner surfaces of the straight pipe section 142 are roughly parallel to the axial direction Da.

The expanded diameter section 143 is embedded in the liner 111 at the shoulder section 114 of the pressure vessel 100, and its diameter increases the further it moves away from the straight pipe section 142 in the axial direction Da of the pressure vessel 100. Of both ends of the expanded diameter section 143 in the axial direction Da of the pressure vessel 100, the end of the expanded diameter section 143 opposite the straight pipe section 142 has a larger diameter than the end connected to the straight pipe section 142, but is embedded in the liner 111 at a predetermined depth D from the outer surface of the liner 111 without being exposed on the outer surface of the liner 111.

The tubular member 140 has, for example, a plurality of through holes 144 spaced apart in the circumferential direction. Each through hole 144 is provided, for example, at both ends of the tubular member 140 in the axial direction Da of the pressure vessel 100. More specifically, the plurality of through holes 144 are provided, for example, between the protruding portion 141 and the straight pipe portion 142, spaced apart in the circumferential direction of the tubular member 140.

In addition, each through hole 144 is provided at intervals in the circumferential direction of the tubular member 140, for example, at the rear end of the tubular member 140 opposite the tip of the neck portion 113 in the axial direction Da of the pressure vessel 100, and at the end of the expanded portion 143 opposite the straight tube portion 142. Each through hole 144 may be, for example, a circular hole, or an oval hole extending in the axial direction Da of the pressure vessel 100 or the circumferential direction of the tubular member 140.

The liner 111 also has a plurality of locking portions 111a filled into a plurality of through holes 144 of the tubular member 140. For example, the plurality of through holes 144 are provided at both ends of the tubular member 140 in the axial direction Da of the pressure vessel 100, and thus the plurality of locking portions 111a are also provided at both ends of the tubular member 140 in the axial direction Da. Each locking portion 111a of the liner 111 prevents relative movement between the liner 111 and the tubular member 140 in the axial direction Da of the pressure vessel 100, and prevents the liner 111 and the tubular member 140 from peeling off in the radial direction of the neck portion 113.

The operation of the pressure vessel 100 of this embodiment is described below.

As described above, the fiber-reinforced resin layer 112 of the pressure vessel 100 is molded, for example, by the RTM method. When molding the fiber-reinforced resin layer 112 by the RTM method, internal pressure may be applied to the liner 111 to prevent deformation of the liner 111 and the reinforced fiber layer around the liner 111 due to the pressure of the uncured curable resin injected into the mold. In this case, the diameter of the cylindrical liner 111 and the reinforced fiber layer expands due to the pressure difference between the pressure of the resin injected into the mold and the internal pressure of the liner 111.

If the diameters of the liner 111 and the reinforced fiber layer expand when the resin is injected into the mold, the fibers that make up the reinforced fiber layer wound around the liner 111 may be pulled from the end in the axial direction Da of the liner 111, i.e., the axial direction Da of the pressure vessel 100, to the center. In this way, if the fibers that make up the reinforced fiber layer on the outside of the liner 111 are pulled from the end in the axial direction Da of the liner 111 to the center, the fibers that are wound with tension on the outside of the liner 111 may relax, and the pressure resistance of the pressure vessel 100 may decrease.

In contrast, the pressure vessel 100 of this embodiment has a liner 111 that forms a space for storing gas, and a fiber-reinforced resin layer 112 that covers the outer surface of the liner 111, and has the following configuration. The pressure vessel 100 has a tubular member 140 embedded in the liner 111 at least in a portion of a cylindrical neck portion 113 provided at the end of the pressure vessel 100 in the axial direction Da. The tubular member 140 has a protrusion 141 that protrudes from the outer surface of the liner 111 and is embedded in the fiber-reinforced resin layer 112.

With this configuration, according to the pressure vessel 100 of this embodiment, during the manufacturing process of the pressure vessel 100, the fibers constituting the fiber reinforced resin layer 112 are wound around the liner 111 in the winding process, and the fibers can be hooked onto the protruding portion 141 of the tubular member 140. As a result, at the end of the axial direction Da of the liner 111, the protruding portion 141 of the tubular member 140 protruding from the outer surface of the liner 111 is embedded into the reinforced fiber layer formed on the outside of the liner 111 in the winding process.

As a result, the protrusion 141 prevents the fibers constituting the reinforced fiber layer around the liner 111 from moving from the end of the liner 111 in the axial direction Da toward the center. This prevents the fibers wound around the liner 111 from relaxing due to tension applied to them, even if the diameter of the liner 111 expands during the impregnation process in which the reinforced fiber layer on the outer side of the liner 111 is impregnated with resin when the fiber reinforced resin layer 112 is molded by the RTM method. As described above, the pressure vessel 100 of this embodiment can prevent the fibers wound around the liner 111 from relaxing during the molding of the fiber reinforced resin layer 112 by the RTM method, thereby improving pressure resistance.

In addition, in the pressure vessel 100 of this embodiment, the protrusion 141 of the tubular member 140 is provided at the end of the axial direction Da of the tubular member 140 located on the tip side of the neck portion 113 of the pressure vessel 100.

With this configuration, according to the pressure vessel 100 of this embodiment, the fibers constituting the fiber reinforced resin layer 112 can be fixed at a position closer to the end of the pressure vessel 100 in the axial direction Da by the protruding portion 141 of the tubular member 140. As a result, in the above-mentioned impregnation process, the protruding portion 141 more effectively prevents the fibers constituting the reinforced fiber layer around the liner 111 from moving from the end of the liner 111 in the axial direction Da toward the center.

In addition, in the pressure vessel 100 of this embodiment, the protrusion 141 of the tubular member 140 is provided around the entire circumference of the tubular member 140, and the diameter increases as it approaches the tip of the neck portion 113 of the pressure vessel 100.

With this configuration, according to the pressure vessel 100 of this embodiment, the protrusion 141 can be easily formed on the tubular member 140. Also, the strength of the protrusion 141 in the axial direction Da of the pressure vessel 100 can be improved, and the tubular member 140 can be made thinner and lighter. Furthermore, the protrusion height H of the protrusion 141 protruding from the outer surface of the liner 111 can be easily controlled. In addition, the surface area of the protrusion 141 exposed from the liner 111 can be increased, and movement of the fibers constituting the fiber reinforced resin layer 112 in the axial direction Da of the pressure vessel 100 can be more effectively prevented.

In addition, in the pressure vessel 100 of this embodiment, the tubular member 140 has a plurality of through holes 144 spaced apart in the circumferential direction. Furthermore, the liner 111 has a plurality of engagement portions 111a filled in the plurality of through holes 144 of the tubular member 140.

With this configuration, according to the pressure vessel 100 of this embodiment, the multiple locking portions 111a of the liner 111 can be engaged with the multiple through holes 144 of the tubular member 140, and the liner 111 and the tubular member 140 can be more firmly integrated. This prevents the tubular member 140 embedded in the liner 111 from peeling off or falling off from the liner 111. As a result, during the manufacturing of the pressure vessel 100, the protrusions 141 can more reliably prevent the fibers wound around the outside of the liner 111 in the winding process from moving from the end of the axial direction Da of the liner 111 to the center in the impregnation process.

In addition, in the pressure vessel 100 of this embodiment, the multiple through holes 144 of the tubular member 140 and the multiple engagement portions 111a of the liner 111 are provided at both ends of the tubular member 140 in the axial direction Da.

With this configuration, the pressure vessel 100 of this embodiment can more firmly integrate the liner 111 and the tubular member 140 compared to when the multiple through holes 144 and the multiple locking portions 111a are provided in other parts of the tubular member 140. This more reliably prevents the tubular member 140 from peeling off or falling off the liner 111, and the protrusions 141 more reliably prevent the fibers wound around the outside of the liner 111 during the manufacture of the pressure vessel 100 from moving from the end to the center in the axial direction Da.

The pressure vessel 100 of this embodiment has a cylindrical body 115 located in the middle in the axial direction Da and having a larger diameter than the neck 113, and a shoulder 114 located between the body 115 and the neck 113 and having a gradually reduced diameter toward the end in the axial direction Da. The tubular member 140 has a straight pipe section 142 embedded in the liner 111 at the neck 113, and an expanded diameter section 143 embedded in the liner 111 at the shoulder 114 and having a larger diameter the further away from the straight pipe section 142 in the axial direction Da.

With this configuration, according to the pressure vessel 100 of this embodiment, the shape of the tubular member 140 from the straight tube section 142 to the expanded diameter section 143 can be matched to the shape of the pressure vessel 100 from the neck section 113 to the shoulder section 114. This allows the tubular member 140 to be embedded in the liner 111 from the neck section 113 to the shoulder section 114 of the pressure vessel 100, improving the strength of the liner 111 and the tubular member 140 against the axial force Da acting on the protrusion 141.

As described above, according to this embodiment, it is possible to provide a pressure vessel 100 that can prevent the fibers wound around the liner 111 from relaxing during molding of the fiber-reinforced resin layer 112 by the RTM method, thereby improving pressure resistance.

Although an embodiment of the pressure vessel according to the present disclosure has been described in detail above using the drawings, the specific configuration is not limited to this embodiment, and even if there are design changes, etc., within the scope that does not deviate from the gist of this disclosure, they are included in this disclosure.

Reference Signs List 100 Pressure vessel 111 Liner 111a Locking portion 112 Fiber reinforced resin layer 113 Neck portion 114 Shoulder portion 115 Body portion 140 Tubular member 141 Projection portion 142 Straight pipe portion 143 Enlarged diameter portion 144 Through hole Da Axial direction

Claims (6)

A pressure vessel comprising a liner forming a space for accommodating a gas and a fiber reinforced resin layer covering an outer surface of the liner,
a tubular member embedded in the liner at least in a portion of a cylindrical neck portion provided at an axial end of the pressure vessel;
The pressure vessel, wherein the tubular member has a protrusion protruding from the outer surface of the liner and embedded in the fiber-reinforced resin layer. The pressure vessel according to claim 1, characterized in that the protrusion is provided at the axial end of the tubular member located on the tip side of the neck portion. The pressure vessel according to claim 2, characterized in that the protrusion is provided around the entire circumference of the tubular member, and the diameter increases as it approaches the tip of the neck portion. The tubular member has a plurality of through holes spaced apart in a circumferential direction,
2. The pressure vessel of claim 1, wherein the liner has a plurality of engagement portions filled into the plurality of through holes of the tubular member. The pressure vessel according to claim 4, characterized in that the multiple through holes and the multiple locking portions are provided at both ends of the tubular member in the axial direction. The pressure vessel has a cylindrical body portion provided at an intermediate portion in the axial direction and having a larger diameter than the neck portion, and a shoulder portion provided between the body portion and the neck portion and having a diameter gradually reduced toward an end portion in the axial direction,
6. The pressure vessel according to claim 5, wherein the tubular member has a straight pipe portion embedded in the liner at the neck portion, and an enlarged diameter portion embedded in the liner at the shoulder portion and having a diameter enlarged as it moves away from the straight pipe portion in the axial direction.

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