齿顶 crest of thread; crown of a tooth; tooth crest; tooth point; tooth-tip; tooth top; addendum◇齿顶间隙 (gear) tip clearance; top clearance of tooth; 齿顶角 addendum angle (伞齿轮的); 齿顶啮合 [机械工程] addendum peak contact; 齿顶线 addendum line; face line of teeth; top line (of teeth); 齿顶圆 addendum [outside; point] circle