| 摘要 |
An injection mold 70 includes a first portion 71, a second portion 72, a third portion 73, and a fourth portion 79. The first portion 71 has three high-density regions H in which there is the highest proportion of the axial direction dimension accounted for by the portion corresponding to cam grooves with respect to the axial direction dimension of a cavity 71a. First gates 74b are disposed at locations corresponding to the high-density regions H, or closer to the high-density regions H than second gates 75b. The average channel sectional area of first runners 74a is larger than the average channel sectional area of second runners 75a.
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