Abstract: A step of forming a low-angle helical layer on an outer surface of at least part of each liner dome portion and an outer surface of a liner cylindrical portion, a step of forming an inner hoop layer on an outer surface of the low-angle helical layer on the liner cylindrical portion, and a step of forming a mixed layer by alternately laminating a low-angle helical layer and an outer hoop layer on an outer surface of the inner hoop layer and low-angle helical layer on each liner dome portion. Then, on the liner cylindrical portion, 90% or more of the sum of the thickness of the inner hoop layer and the thickness of the outer hoop layer in the mixed layer is arranged within the range of 75% of the fiber reinforced plastics layer adjacent to the liner in a thickness direction of the fiber reinforced plastics layer.

Abstract: A liner includes dome sections having outer surfaces along an uniform stress surface at both ends in an axial direction, and nozzles are mounted on the dome section by introducing nozzle flanges into pedestal sections of apexes of the dome sections. Then, ring-shaped caps having the same linear expansion coefficient as the liner and inner surfaces in a curved surface shape of outer surfaces of the dome sections and the nozzle flanges are mounted on boundary portions between the nozzle flanges and the pedestal sections. In forming a fiber layer after that, a helical winding layer is formed first by winding a fiber bundle disposed at the dome sections to cover the dome sections while including the nozzle flanges.

Abstract: In a high-pressure tank including a reinforcement layer and a protective layer, using the same resin for the reinforcement layer and the protective layer is likely to cause bubbles produced in the course of curing the resin to remain on the surface of the tank. There is also a possibility that cloudiness occurs on the surface of the tank during the use of the high-pressure tank. There is accordingly provided a high-pressure tank, comprising a liner; a reinforcement layer formed on the liner and including a thermosetting first resin and a fiber; and a protective layer formed on the reinforcement layer and including a thermosetting second resin. A second gelation temperature that is a gelation temperature of the second resin is higher than a first gelation temperature that is a gelation temperature of the first resin. A viscosity of the second resin is lower than a viscosity of the first resin at the first gelation temperature.

Abstract: There are disclosed a tank having a structure which achieves both a burst strength and a fatigue strength, and a manufacturing method of the tank. In order to realize this, in a tank comprising a liner, and an FRP layer including a hoop layer and a helical layer formed by winding fibers around the outer periphery of the liner, at least an innermost helical layer is formed as a smooth helical layer. When the smooth helical layer, i.e., a helical layer which does not have any unevenness or which has only little unevenness is formed, the unevenness can be prevented from being transferred to the hoop layer adjacent to the helical layer. When structural bends (undulations) of the fibers of the hoop layer are suppressed, a fatigue strength of the fibers themselves can be enhanced.

Abstract: A tank that includes layers of fiber reinforced plastics (FRP) formed by alternately winding hoop and helical bundles of fiber over its outer surface. The winding produces stepped portions, i.e. unevenness, in a helical layer positioned as the innermost layer. Such unevenness affects an outer layer (especially a hoop layer) directly adjacent to the innermost helical layer and lowers fatigue strength of the adjacent outer layer. In order to prevent this fatigue strength decrease, the bundle of fiber used for the innermost helical layer has a smaller sectional area than the bundles used for the outer layers. Consequently, decreasing the sectional area of the innermost helical bundle decreases the stepped portions, which, in turn, decreases the transfer of unevenness to the outer layer (especially a hoop layer) directly adjacent to the helical layer. As a result, fatigue strength of the adjacent outer layer (especially a hoop layer) increases.

Abstract: A tank which optimizes a laminating configuration of hoop layers and helical layers to enhance an efficiency of strength development by wound fibers, and a manufacturing method of the tank. The tank includes a liner, and an FRP layer constituted of an axial fiber layer formed by winding fibers around the outer periphery of the liner at a winding angle in a range exceeding 0° and less than 30° with respect to a tank axis in the center of the tank and a peripheral fiber layer formed by winding the fibers around the outer periphery of the liner at a winding angle in a range of 30° or more and less than 90° with respect to the tank axis, and folded fiber ends of the peripheral fiber layer in a tank axial direction draw a track.

Abstract: A step of forming a low-angle helical layer on an outer surface of at least part of each liner dome portion and an outer surface of a liner cylindrical portion, a step of forming an inner hoop layer on an outer surface of the low-angle helical layer on the liner cylindrical portion, and a step of forming a mixed layer by alternately laminating a low-angle helical layer and an outer hoop layer on an outer surface of the inner hoop layer and low-angle helical layer on each liner dome portion. Then, on the liner cylindrical portion, 90% or more of the sum of the thickness of the inner hoop layer and the thickness of the outer hoop layer in the mixed layer is arranged within the range of 75% of the fiber reinforced plastics layer adjacent to the liner in a thickness direction of the fiber reinforced plastics layer.

Abstract: A high-pressure tank configured to store a fluid includes: a liner; and a fiber-reinforced resin layer configured to include a fiber and to cover surface of the liner. The liner includes: a cylindrical liner portion in a cylindrical shape; and dome liner portions in a dome shape connected with respective sides of the cylindrical liner portion, each dome liner portion being connected with the cylindrical liner portion, such that an outer surface of the dome liner portion is inclined at a predetermined angle to an outer surface of the cylindrical liner portion. The fiber-reinforced, resin layer includes a hoop layer formed on the outer surface of the cylindrical liner portion to cover the outer surface of the cylindrical liner portion and provided by hoop winding that winds the fiber substantially perpendicularly to a central axis of the cylindrical liner portion.

Abstract: There is avoided a phenomenon where owing to an influence of a stepped portion of the surface of a helical layer positioned in an inner layer of an FRP layer, a fatigue strength of a layer (especially, a hoop layer) adjacent to the outside of the helical layer lowers. To realize this, there is disclosed a tank comprising a liner, and an FRP layer constituted of hoop layers and helical layers alternately formed by winding fiber bundles around the outer periphery of the liner, and in at least one of a plurality of helical layers positioned in an inner layer of the FRP layer, a sectional area of the fiber bundle constituting the helical layer is set to be smaller than that of the fiber bundle constituting another layer formed outside the helical layer. When the helical layer is formed by using this fiber bundle having the small sectional area, unevenness in the helical layer becomes small, and the unevenness can be prevented from being transferred to the other layer (e.g.

Abstract: There are disclosed a tank which optimizes a laminating configuration of hoop layers and helical layers to enhance an efficiency of strength development by wound fibers, and a manufacturing method of the tank. In order to realize this, the tank includes a liner, and an FRP layer constituted of an axial fiber layer formed by winding fibers around the outer periphery of the liner at a winding angle in a range exceeding 0° and less than 30° with respect to a tank axis in the center of the tank and a peripheral fiber layer formed by winding the fibers around the outer periphery of the liner at a winding angle in a range of 30° or more and less than 90° with respect to the tank axis, and folded fiber ends of the peripheral fiber layer in a tank axial direction draw a track which narrows from the inside toward the outside in a laminating direction of the fiber layers.

Abstract: There are disclosed a tank having a structure which achieves both a burst strength and a fatigue strength, and a manufacturing method of the tank. In order to realize this, in a tank comprising a liner, and an FRP layer including a hoop layer and a helical layer formed by winding fibers around the outer periphery of the liner, at least an innermost helical layer is formed as a smooth helical layer. When the smooth helical layer, i.e., a helical layer which does not have any unevenness or which has only little unevenness is formed, the unevenness can be prevented from being transferred to the hoop layer adjacent to the helical layer. When structural bends (undulations) of the fibers of the hoop layer are suppressed, a fatigue strength of the fibers themselves can be enhanced.

Abstract: A pressure container includes a metal socket and a CFRP layer that contacts the metal socket. A metal oxide layer is formed on a first contact area where the socket contacts the CFRP layer. The socket may be made of aluminum or aluminum alloy, and the oxide layer may be formed by anodizing the socket.

Abstract: Disclosed is a seal structure of a high-pressure tank capable of properly securing seal efficiency. The seal structure of the high-pressure tank includes a plurality of seal members that have mutually different seal properties and that are installed between a ferrule of the high-pressure tank and a valve body attached to the ferrule. One of the plurality of seal members has low temperature resistance, and the other has high temperature resistance. A first seal member is an O-ring formed of butyl rubber or silicone. A second seal member is an O-ring formed of EPDM. Furthermore, the two O-rings are different in gas permeability from each other. This seal structure can be applied between the ferrule and the valve body, in addition, between the ferrule and a liner, between the ferrule and a shell, and between the valve body and the shell.

Abstract: A pressure container includes a metal socket and a CFRP layer that contacts the metal socket. A metal oxide layer is formed on a first contact area where the socket contacts the CFRP layer. The socket may be made of aluminum or aluminum alloy, and the oxide layer may be formed by anodizing the socket.

Abstract: Disclosed is a seal structure of a high-pressure tank capable of properly securing seal efficiency. The seal structure of the high-pressure tank includes a plurality of seal members that have mutually different seal properties and that are installed between a ferrule of the high-pressure tank and a valve body attached to the ferrule. One of the plurality of seal members has low temperature resistance, and the other has high temperature resistance. A first seal member is an O-ring formed of butyl rubber or silicone. A second seal member is an O-ring formed of EPDM. Furthermore, the two O-rings are different in gas permeability from each other. This seal structure can be applied between the ferrule and the valve body, in addition, between the ferrule and a liner, between the ferrule and a shell, and between the valve body and the shell.