Steering shaft with misassembly prevention structure

1. A steering shaft with a misassembly prevention structure comprising:

a shaft comprising a torsion bar formed in the axial direction from an end of the shaft, serrations formed on the outer peripheral surface of the shaft from the area where the formation of the torsion bar is terminated, and a groove formed as a recess from the area where the formation of the serrations is terminated;

a slip member configured to be coupled with the shaft by inserting the torsion bar into the slip member;

a yoke comprising serrations formed on the inner peripheral surface of the yoke to be tooth-meshed with the serrations formed on the shaft when the shaft coupled with the slip member is inserted into the yoke, and a bolt tightening hole formed to bolt the yoke with the shaft;

a groove formed along the outer peripheral surface of the torsion bar; and

a ring inserted into the groove.

2. The steering shaft as claimed in claim 1 , wherein the slip member is a bush type, in which the opposite sides in the axial direction are opened, or a cap type, in which only one side in the axial direction is opened.

3. The steering shaft as claimed in claim 1 , wherein the slip member has a slit formed in the axial direction.

4. The steering shaft as claimed in claim 1 , wherein a groove is formed along the inner peripheral surface of the slip member, and

the ring is inserted into a space formed as the groove formed along the inner peripheral surface of the slip member and the groove formed along the outer peripheral surface of the torsion bar are opposed to each other.

5. The steering shaft as claimed in claim 1 , wherein the inner peripheral surface of the slip member is diametrically expanded at an area corresponding to the area where the groove formed along the outer peripheral surface of the torsion bar is formed.

6. The steering shaft as claimed in claim 1 , wherein the slip member is formed from a plastic material or a metal material.