It is the outside circle (tooth tip circle) of the external spline or the root circle of the internal spline.

它是外花键的外圆(齿顶圆)，和内花键的齿根圆。

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This circle along with the tooth tip circle (or start of chamfer circle) determines the limits of tooth profile requiring control.

渐开线终止圆与齿顶圆（或者修缘线的起点所在的圆）共同限制了所要求控制的渐开线齿廓的范围。

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This circle along with the tooth tip circle (or start of chamfer circle) determines the limits of tooth profile requiring control.

渐开线终止圆与齿顶圆（或者修缘线的起点所在的圆）共同限制了所要求控制的渐开线齿廓的范围。

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