Method of manufacturing reinforcement layer
A method of manufacturing a reinforcement layer comprises a preparatory step of preparing to-be-wound fiber, and a formation step of forming an uncured sheet layer including multiple layers of the to-be-wound fiber stacked on an outer circumferential surface. In the formation step, the to-be-wound fiber is wound on the outer circumferential surface in such a manner that, regarding an outer layer of the uncured sheet layer and an inner layer of the uncured sheet layer closer to the outer circumferential surface than the outer layer and adjacent to the outer layer in a stacking direction of the to-be-wound fiber, two end portions of the outer layer are located between two end portions of the inner layer in an axis direction extending along a center axis of a winding target member.
1. A method of manufacturing a reinforcement layer made of fiber-reinforced resin and arranged around a liner forming a body of a tank, the method comprising:
a preparatory step of preparing to-be-wound fiber as sheet-like fiber impregnated with resin and having one end portion, an opposite end portion, and two lateral portions connecting the one end portion and the opposite end portion, the to-be-wound fiber having a width reduced stepwise or continuously with increasing distance from the one end portion and decreasing distance to the opposite end portion such that the two lateral portions are closer to one another in a width direction of the to-be-wound fiber at a first position closer to the opposite end portion than a second position closer to the one end portion; and
a formation step of forming an uncured sheet layer including multiple layers of the to-be-wound fiber stacked on an outer circumferential surface having a cylindrical shape of a winding target member by winding the to-be-wound fiber sequentially in a circumferential direction of the outer circumferential surface in order from the one end portion toward the opposite end portion, wherein
in the formation step, the to-be-wound fiber is wound on the outer circumferential surface in such a manner that, regarding an outer layer of the uncured sheet layer and an inner layer of the uncured sheet layer closer to the outer circumferential surface than the outer layer and adjacent to the outer layer in a stacking direction of the to-be-wound fiber, two lateral portions of the outer layer are located between two lateral portions of the inner layer in an axis direction extending along a center axis of the winding target member.
2. The method of manufacturing the reinforcement layer in accordance with claim 1 , wherein
the preparatory step comprises:
a step of preparing unformed fiber as sheet-like fiber impregnated with the resin and having a first end portion corresponding to the one end portion and a second end portion corresponding to the opposite end portion; and
a step of forming the to-be-wound fiber by pressing a recess of a roller against the unformed fiber while transferring the unformed fiber sequentially in order from the first end portion toward the winding target member, the recess having a width reduced with decreasing distance to a bottom of the recess, and
in the step of forming the to-be-wound fiber, the unformed fiber is pressed with the recess in such a manner that a part of the unformed fiber to be wound on a position separated further from the outer circumferential surface is located at a position closer to the bottom.
3. The method of manufacturing the reinforcement layer in accordance with claim 2 , wherein
the step of forming the to-be-wound fiber comprises a step of increasing tension applied to a part of the unformed fiber to be wound on a position separated further from the outer circumferential surface by increasing force in pressing the unformed fiber with the recess at this part.
4. The method of manufacturing the reinforcement layer in accordance with claim 1 , wherein
the preparatory step is a step of forming the to-be-wound fiber in advance before the formation step is started.
5. The method of manufacturing the reinforcement layer in accordance with claim 4 , wherein
the preparatory step is a step of forming the to-be-wound fiber in advance by cutting sheet-like fiber.
6. The method of manufacturing the reinforcement layer in accordance with claim 4 , wherein
the to-be-wound fiber formed in advance in the preparatory step has a fiber density increased stepwise or continuously with increasing distance from the one end portion and decreasing distance to the opposite end portion.
7. The method of manufacturing the reinforcement layer in accordance with claim 4 , wherein the to-be-wound fiber formed in advance in the preparatory step has a thickness increased stepwise or continuously with increasing distance from the one end portion and decreasing distance to the opposite end portion.