Tank

1. A tank, comprising:

a liner having a cylindrical trunk portion and a hemispherical dome portion provided at both ends of the trunk portion in a central axis direction;

a fiber-reinforced resin layer formed on an outer peripheral surface of the liner;

a collet ring that is installed at a top of the dome portion for attachment of a valve and has a protrusion portion protruding in the axial direction from the dome portion toward the trunk portion; and

a metallic reinforcement member separate from the collet ring and integrally molded with the liner on an inside surface of the liner and contained completely within an internal space defined by the liner, wherein

the reinforcement member is arranged in the dome portion at least at a shoulder portion near a boundary between the dome portion and the trunk portion and is not arranged at least at part of the trunk portion.

2. The tank in accordance with claim 1 ,

wherein a distance from the central axis of the liner to the shoulder portion is equal to a radius of an inner surface of the trunk portion multiplied by 0.9.

3. The tank in accordance with claim 2 ,

wherein

the liner covers an outer surface of the protrusion portion, and

the reinforcement member is arranged on the liner continuously from the shoulder portion to a portion covering the protrusion portion and the portion covering the protrusion portion.

4. The tank in accordance with claim 3 ,

wherein the reinforcement member is in contact with at least part of the outer surface of the protrusion portion.

5. The tank in accordance with claim 4 , wherein

the liner is formed from a resin,

the liner has:

a first contact portion that is in contact with an outer surface of a first cover portion of the reinforcement member arranged on the liner from the shoulder portion to the portion covering the protrusion portion; and

a second contact portion that is in contact with an outer surface of a second cover portion of the reinforcement member arranged on the liner at the portion covering the protrusion portion, and

the reinforcement member has a through hole that penetrates through the reinforcement member in a thickness direction such that the resin flows between the first contact portion and the second contact portion.

6. The tank in accordance with claim 3 , wherein

the liner is formed from a resin,

the liner has:

a first contact portion that is in contact with an outer surface of a first cover portion of the reinforcement member arranged on the liner from the shoulder portion to the portion covering the protrusion portion; and

a second contact portion that is in contact with an outer surface of a second cover portion of the reinforcement member arranged on the liner at the portion covering the protrusion portion, and

the reinforcement member has a through hole that penetrates through the reinforcement member in a thickness direction such that the resin flows between the first contact portion and the second contact portion.

7. The tank in accordance with claim 1 ,

wherein

the liner covers an outer surface of the protrusion portion, and

the reinforcement member is arranged on the liner continuously from the shoulder portion to a portion covering the protrusion portion and the portion covering the protrusion portion.

8. The tank in accordance with claim 7 ,

wherein the reinforcement member is in contact with at least part of the outer surface of the protrusion portion.

9. The tank in accordance with claim 8 , wherein

the liner is formed from a resin,

the liner has:

a first contact portion that is in contact with an outer surface of a first cover portion of the reinforcement member arranged on the liner from the shoulder portion to the portion covering the protrusion portion; and

a second contact portion that is in contact with an outer surface of a second cover portion of the reinforcement member arranged on the liner at the portion covering the protrusion portion, and

the reinforcement member has a through hole that penetrates through the reinforcement member in a thickness direction such that the resin flows between the first contact portion and the second contact portion.

10. The tank in accordance with claim 7 , wherein

the liner is formed from a resin,

the liner has:

a first contact portion that is in contact with an outer surface of a first cover portion of the reinforcement member arranged on the liner from the shoulder portion to the portion covering the protrusion portion; and

a second contact portion that is in contact with an outer surface of a second cover portion of the reinforcement member arranged on the liner at the portion covering the protrusion portion, and

the reinforcement member has a through hole that penetrates through the reinforcement member in a thickness direction such that the resin flows between the first contact portion and the second contact portion.

11. The tank in accordance with claim 1 ,

wherein the reinforcement member covers continuously from the shoulder portion as an end to part of an inner surface of the trunk portion.

12. A tank, comprising:

a liner having a cylindrical trunk portion and a hemispherical dome portion provided at both ends of the trunk portion in a central axis direction;

a fiber-reinforced resin layer formed on an outer peripheral surface of the liner;

a collet ring that is installed at a top of the dome portion for attachment of a valve and has a protrusion portion protruding in the axial direction from the dome portion toward the trunk portion; and

a metallic reinforcement member separate from the collet ring and integrally molded with the liner, wherein

the reinforcement member is arranged in the dome portion at least at a shoulder portion near a boundary between the dome portion and the trunk portion and is not arranged at least at part of the trunk portion.