| 摘要 |
PROBLEM TO BE SOLVED: To insert-mold an impeller with a built-in magnet for a flowmeter, so that no magnet is displaced. SOLUTION: Related to a manufacturing method of an impeller with a built-in ring magnet for a flowmeter, a ring magnet 13 is attached to an axis part 91 of a primary molding 9 of the impeller, which is forcedly rotated by a prescribed angle around a revolution center line 3a in one direction so that the inside surface of its center hole 131 crushes four corner parts 911 of the axis part 91. As a result, the ring magnet 13 is so temporarily fitted as not to come off the axis part 91 of the primary molding 9. Since a main body part 61 is formed by insert-molding in this condition, no ring magnet 13 displaces from an end surface 901 under a dead weight nor sticks to a movable-side die by its own magnetic force. So, an impeller 6 is formed for good rotational balance as no ring magnet 13 deviates from the primary molding 9 nor rises.
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