Cleavage method, rotor manufacturing method, and cleavage apparatus

A cleavage method for cleaving a plate-shaped workpiece made of a magnetic material formed with linear recesses on a surface, the workpiece being to be cleaved along each of the linear recesses, wherein

• the linear recesses are formed at two or more positions on the plate-shaped workpiece to cleave the workpiece into three or more parts,
• the method includes:
• a first positioning step of holding the plate-shaped workpiece by a positioning means in place in a direction perpendicular to the linear recesses to position a first linear recess of the linear recesses in place;
• a first clamping step of clamping one side of the first linear recess by a fixing clamp with a predetermined clamping force and clamping the other side by a rotating clamp with a predetermined clamping force while the plate-shaped workpiece is positioned by the positioning means;
• a first cleaving step of moving back the positioning means and rotationally separating the rotating clamp while maintaining the predetermined clamping force of the rotating clamp;
• a second positioning step of releasing the fixing clamp and the rotating clamp and causing the positioning means to position a second linear recess in place;
• a second clamping step of clamping one side of the second linear recess by the fixing clamp with the predetermined clamping force and clamping the other side by the rotating clamp with the predetermined force while the plate-shaped workpiece is positioned by the positioning means, and
• a second cleaving step of moving back the positioning means and rotationally separating the rotating clamp while maintaining the predetermined clamping force of the rotating clamp;
• wherein cleaved parts obtained in the first cleaving step and the second cleaving step are held with a cleaved face being abutted against a cleaved face of the plate-shaped workpiece, and
• the plate-shaped workpiece cleaved into three of more parts is held and carried out with their cleaved faces being abutted against each other.