Adjustment device e.g. rear fitting of vehicle seat, has cam unit that drives rings provided with external and internal teeth including teeth portion whose depth is set to preset value which reduces in region of head circle

摘要

The device has first fitting portion (11) on which toothed ring (17) with internal teeth (18) is formed and a second fitting portion on which a toothed ring (15) with external teeth (16) is formed. An eccentric cam unit drives the toothed rings. The depth of teeth portion (Z16) of the external teeth and teeth portion (Z18) of internal teeth is set to specific value, while defining head circle (16K,18K) and root circle (16F) between the teeth portions. The depth of the teeth is reduced in the region of the head circle.