| 摘要 |
<p>Bonding strength between layers is enhanced. A bonding layer (3) is formed between layers (1, 2), helical reinforcing members (4a, 5a) are wound between the bonding layer (3) and the layers (1, 2) such that the reinforcing members (4a, 5a) are tilted opposite to each other, and as a result, reinforcing layers (4, 5) are formed on the inner and outer peripheral surfaces, respectively, of the bonding layer (3). By this, the outer peripheral surface of the inner layer (1) and the inner peripheral surface of the bonding layer (3) are in direct contact with and secured to each other through helical gaps formed by the helical reinforcing members (4a), and the inner peripheral surface of the outer layer (2) and the outer peripheral surface of the bonding layer (3) are in direct contact with and secured to each other through helical gaps formed by the helical reinforcing members (5a).</p> |
