Patent ID: 7237976

Claim:
A key-engaging part structure of an axial-hole member, having an axial hole fit to a shaft, where the key-engaging part structure is connected to the shaft in a power transmittable manner via a key engaged with the key-engaging part structure formed on an inner peripheral portion of the axial-hole member, wherein a through hole is formed in the axial-hole member such that the through hole extends from the outer peripheral portion of the axial-hole member to the axial hole, wherein the through hole is longer in an axial direction than a radial direction of the axial hole member, leaving both axial end portions of the axial-hole member intact, a key way is formed on an inner periphery of the axial-hole member at a position symmetrical with the through hole in the radial direction, wherein the key and the shaft are assembled into the axial-hole member, such that the shaft is co-axially aligned to the axial hole member, and wherein the key transmits rotational power between the key-engaging part and the shaft, and wherein a longitudinal direction of the key and the keyway is the same direction as an axial direction of the axial-hole member wherein an insertion groove is formed in the inner peripheral portion of a part of the axial hole in an axial direction so as to allow the insertion of the key in the axial direction.