Torque transmission shaft

A torque transmission shaft, comprising:

• a shaft having a hollow shape and comprising a yoke portion provided on one end portion in an axial direction;
• a slit extending in the axial direction and provided on the other end portion in the axial direction;
• and a female serration provided on an inner peripheral surface of the other end portion in the axial direction;
• and
• a clamp having a partial cylindrical shape and comprising a non-continuous portion arranged at one location in a circumferential direction;
• and a pair of flange portions arranged on both sides of the non-continuous portion in the circumferential direction and respectively having an installation hole into which a tightening member is inserted;
• wherein
• the clamp is externally fitted around the other end portion in the axial direction of the shaft, and capable of reducing a diameter of the other end portion in the axial direction of the shaft by reducing a width dimension of the non-continuous portion,
• the shaft has a small-diameter cylindrical portion at the other end portion in the axial direction, the female serration is provided only on an inner peripheral surface of the small-diameter cylindrical portion, and
• one end portion in the axial direction of the slit is located farther on one side in the axial direction than the small-diameter cylindrical portion, and is positioned farther on the one side in the axial direction than one end edge in the axial direction of the female serration and in a portion having an outer diameter dimension and inner diameter dimension that are larger than those of the small-diameter cylindrical portion.