| 摘要 |
The machine shapes crown wheels, where the flanks of the crown-wheel teeth have minimum (~amin) and maximum pressure angles respectively at the innermost and outermost portions, and work with a cylindrical pinion whose tooth-pitch angle (~f) is equal to 360 deg divided by the number of pinion teeth. The machine has a tool (12) with a working surface (9), which in a cross-section through its rotation axis has a profile incorporating several teeth of the same shape as those of the pinion, and is moved to and fro along the rotation axis of the pinion when meshing with the finished crown-wheel. On reversal of movement, the work is indexed round its axis, and the tool is rocked through an angle to either side of a centre line (V), so that tool and work turn for distances corresponding to the ratio between the numbers of pinion and crown-wheel teeth. The rocking angle is greater than half the tooth-pitch angle of the pinion and less than the minimum pressure angle of the crown-wheel teeth.
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