| 摘要 |
PURPOSE:To elevate the injection pressure and thereby improve the dimensional accuracy of a molding, by supporting the outer surrounding of an outer circle by placing an outer circle supporting material contacted with the outer cylinder surface of the outer circle, over almost whole length of its axis direction, by forming a resin housing and the outer circle in a body and by drawing out the outer circle supporting material from the resin housing. CONSTITUTION:A top metal force 15 having a projection 14 is put on a bottom metal, force 11 in such a way that both outer surfaces are coincided with each other and it is then fixed to from a cavity 16 between the projection 14 of the top metal force 15 and the cavity 12 of the bottom metal force 11. A synthetic resin plastic 18 is injected under high pressure in the cavity 16. Even if the plastic is injected under high pressure like this, the injection pressure hardly acts on the outer cylinder surface 6B, 6B,... of an outer circle 6a which is weak against the pressure from the outside and the outer cylinder surface 6B therefore does not either shrink or deform. It is because the outer circle supporting material 20, 20,... tightly contacts and adheres with the outer cylinder surface 6B, 6B,... over the whole length of its axis direction and the pressure acting on it is decreased by the outer circle supporting material 20, 20,... and the outer cylinder surface 6B, 6B... thereby does not either shrink or deform. |
