JPS6471617A - Turning broach - Google Patents

Abstract

PURPOSE:To improve the discharge quality of cutting chips by providing a throw away tip in an intermediate part of a broach main unit and forming a cutting edge of the throw away tip to a V-shape in which the cutting edge tilts toward the root end side of the broach main unit in accordance with its position from the central part toward the side surface side in the width direction. CONSTITUTION:A broach main unit forms cutting edges 35, 35 of a tip 30 in its intermediate part into a V-shape so as to tilt these cutting edges 35, 35 gradually toward the root end side of the broach main unit in accordance with its position from the central part toward the side surface side in the width direction, while a flank 30b is gradually tilted to a bottom surface side of the broach main unit in accordance with its position toward the root end side. Consequently, a cut material is cut one after another in a manner wherein each cutting edge 35, 35 of two or more tips 30 cuts a crossing point part of the cutting edges 35, 35 into the central part of the cut material positioned between journal diameter widths. A chip, cut out by the cutting edges 35, 35, is divided into two parts bordering on the crossing point part of the cutting edges 35, 35, being discharged toward the bottom surface side of the broach main unit. Accordingly, the cutting chip can be effectively discharged.