Patent ID: 8839699

Claim:
A long shaft inner surface machining apparatus that cuts an inner surface of a long shaft including a prepared hole penetrating therethrough in an axial direction so as to copy the prepared hole, wherein the long shaft inner surface machining apparatus comprises: (a) a long shaft support device that fixes the long shaft so as not to bend; (b) a machining head that is insertable into the prepared hole of the long shaft in an axial direction, wherein the machining head includes a blade movable in a radial direction for inner surface machining, wherein the machining head is operable to let a rotation center of the blade coincide with a first shaft axis of the prepared hole, and wherein the machining head is movable within the prepared hole in the axial direction; (c) a head support device that is coupled with the machining head from a first end of the long shaft through the prepared hole, and the head support device moves the machining head in the axial direction; and (d) a blade drive device that is coupled with the machining head from a second end of the long shaft through the prepared hole, and the blade drive device rotary-drives the blade around a second shaft axis, wherein the machining head comprises: an inner surface copy head to expand a diameter thereof radially by hydraulic pressure so as to let a shaft axis thereof coincide with the shaft axis of the prepared hole and is movable in the axial direction within the prepared hole; and a blade head supported by the inner surface copy head rotatably around a shaft axis thereof, and including an axial direction moving member movable in the axial direction where axial direction movement thereof moves the blade in the radial direction, wherein the head support device includes a boring bar with one end thereof coupled with the inner surface copy head and extending in the axial direction, and a bar moving device that moves the boring bar in the axial direction so as not to rotate, and the blade drive device includes: a main rod with one end thereof coupled with the blade head and extending in the axial direction; and a rotary drive device that rotary-drives the main rod around a shaft axis and moves in the axial direction so as to follow the machining head.