Cam mechanism, cam mechanism manufacturing method, camshaft manufacturing method, NC rotary table

A cam mechanism comprising a base, a roller gear, and a camshaft, wherein:

• the roller gear and the camshaft are rotatably supported by the base;
• the roller gear has a turret and a plurality of cam followers mounted on a circumference of the turret;
• the cam shaft has a tapered rib having a first tapered rib and a second tapered rib, and a shaft portion;
• the first and second tapered ribs are each engaged with the cam followers;
• the first and second tapered ribs are configured to rotate relative to each other around a rotation axis of the shaft portion during adjustment of preload at which the first and second tapered ribs are pressed against the cam followers;
• and
• after the adjustment of the preload, the second tapered rib is fixed to the shaft portion, and the first and second tapered ribs are prevented from rotating relatively;
• wherein
• the camshaft has a first camshaft member, a second camshaft member, a fastening member, and an axial movement preventing member;
• the first camshaft member is a member in which the shaft portion and the first tapered rib are integrally formed;
• the second camshaft member is a member having the second tapered rib and a through hole;
• the first and second camshaft members are connected rotatably relative to each other around the rotation axis of the shaft portion by inserting the shaft portion into the through hole;
• the fastening member is configured to allow switching between fastening and unfastening of the shaft portion and the second camshaft member;
• the axial movement preventing member is configured to prevent the first and second tapered ribs in contact with each other from moving axially relative to each other;
• and
• the fastening member is positioned between the second camshaft member and the axial movement preventing member.