Patent ID: 8042443
Filing Date: 2011-10-25
Classification: B23D,Y10T

Abstract:
1. A disc-shaped tool comprising: a plurality of overlapping virtual regions so formed as to be surrounded by two radius lines extending from a rotation center of a disc-shaped base metal and two concentric circles on the base metal disposed around the rotation center, said virtual regions overlapping continuously in a circumferential direction on the disc-shaped base metal, each virtual region overlapping each adjacent virtual region in the circumferential direction, while an entire slit is provided in each one of the virtual regions, the slit making contact with all of the two corresponding radius lines and the two concentric circles, wherein the slits all make contact with the same two concentric circles, wherein each end portion of each slit extends so as to form an arc that is substantially coincident with a respective one of the concentric circles, wherein a virtual region angle around the rotation center formed by the two radius lines from a same virtual region is equal to or less than 90°; the virtual regions are 4 to 24 in number; a central concentric circle located in a center of an interval of the two concentric circles forming the virtual region is in a range of 0.6 r to 0.8 r with respect to the rotation center of the base metal when a maximum gullet bottom radius of the base metal is r; an overlapping of the virtual regions continuously adjoining each other is in a range of 0° to 12° in terms of a central angle around the rotation center, the central angle formed by two radius lines from adjacent virtual regions; a minimum distance between adjacent slits is equal to or more than 0.05 r; and a ratio q of a length of an arc of the central concentric circle extending across all of the virtual region with respect to a radial distance between the two concentric circles in the virtual region is 3≦q≦6.