Device for automatically aligning inner hole of gear with key groove and alignment method thereof

The invention discloses a device for automatically aligning an inner hole of a gear with a key groove and an alignment method of the device. The device comprises a cylindrical finger air cylinder, and the finger air cylinder comprises a plurality of clamping fingers capable of moving in the radial direction of the finger air cylinder; a follower mounting seat is fixed on the clamping finger, and at least one cam bearing follower is mounted on each of the left side and the right side of the follower mounting seat. The left cam bearing follower and the right cam bearing follower are symmetrically designed on the mounting plates, so that when one cam bearing follower is in contact with a key groove and is sunk into the key groove, the other cam bearing follower on the same mounting plate can still be tightly attached to the hole wall of an inner hole of a gear; and the aim of aligning the inner hole of the gear is fulfilled by virtue of the relative rotation motion of the cam bearing followers except the cam bea