| 摘要 |
A rotary drive member such as a gear or pulley has a hub portion that can be mounted on a shaft for rotation about the axis of the shaft, a rim portion that can be engaged by another drive member such as a gear, chain or belt as the rotary drive member rotates about the axis of the shaft, and a radially extending web that rigidly interconnects the hub and rim portions. The rotary drive member is formed by injection molding plastics material to provide a unitary, one-piece plastics member that envelops selected portions of a pair of inner and outer insert members that extend concentrically about the shaft rotation axis and that are formed from metal. The inner insert takes the form of an elongate, tubular metal sleeve that defines inner diameter portions of the hub portion of the rotary member. The outer insert takes the form of an annular metal disc that extends radially with respect to the shaft rotation axis to define portions of the radially extending web. The injection-molded plastics member envelopes the periphery of the tubular inner insert, envelopes inner and outer diameter regions of the annular outer insert, serves to rigidly drivingly interconnect the inner and outer inserts, and defines selected parts of the hub and rim portions of the rotary drive member including a drive formation on the rim for engaging another drive member such as a gear, chain or a belt.
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