"齿高变位量" can be translated as "addendum modification for height" or more precisely in a mechanical engineering context, "profile shift in the height direction (of gear teeth)" or simply "tooth height modification".
Among these, "addendum modification" is a commonly used term in gear technology to refer to adjustments made to the tooth profile, including height-related changes, though it may more broadly encompass any modifications to the addendum (the top part of the gear tooth). If you specifically want to emphasize the height aspect, "tooth height modification" is a straightforward and clear choice.
For a more technical and precise description in gear design documentation, you might use "profile shift in the height direction of gear teeth" to convey the exact meaning of adjusting the tooth height through profile modification.