| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a resin molding having a shape with which defects caused by remaining cavities can be prevented and demolding resistance from a core mold can be adjusted at a proper level.SOLUTION: A resin molding 1 molded through injection molding of synthetic resin includes a hollow cylindrical part 11. The inner peripheral surface of the cylindrical part 11 has no undercut in a demolding direction, the inner peripheral surface being divided into a plurality of partial regions (11a, 11b, 11c, 11d, and so on) extending linearly along in the demolding direction, the adjacent partial regions being provided with steps so that the adjacent partial regions offset each other in the radial direction of the cylindrical part. The steps are extending linearly along in the demolding direction, and the size of the steps in the radial direction of the cylindrical part is set to 0.5 to 20% of the thickness of the cylindrical part 11.</p> |
