JPH0470418U - - Google Patents

Description

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, FIG. 1 is a side view of the gun drill, FIG. 2 is a view of the tip in the axial direction, and FIG. 3 is a view of the tip of the conventional gun drill in the axial direction. , Figure 4 is a diagram showing the cutting power when drilling is performed with the gun drill of the present invention and the conventional gun drill, and Figure 5 is a diagram showing the cutting power when drilling is performed with the gun drill of the present invention and the conventional gun drill. FIG. 11...shank, 12...cutting tip, 16
... Chip discharge groove, 18 ... Cutting edge, 19 ... Straight cutting edge, 20 ... Inclined part, 21 ... Concave curved part, 22
...Concave cutting edge, 23...Convex curved cutting edge.

Claims (1)

[Claims for Utility Model Registration] (1) A cutting tip is brazed to the tip of a shank that is hollow inside and can be rotated about its axis, and a cutting tip is brazed to the tip of the shank, and a cutting tip is attached to the side of the cutting tip from the tip side to the proximal side. A chip discharge groove extending to the axial direction is provided, and a curved cutting edge that is convex toward the rotation direction when viewed from the axial tip is provided at the intersecting ridge line between the wall portion of the chip discharge groove facing the rotation direction and the tip flank. is provided on the rotation center side of the cutting edge, and a linear cutting edge located on the radial line passing through the axis is provided at the outermost position of the cutting edge, and this linear cutting edge and the above The convex curved cutting edge is provided with an inclined part that is inclined in the radial positive direction with respect to the straight cutting edge when viewed from the tip in the axial direction, and the convex curve that forms a curve from the inner peripheral end of this inclined part. A gun drill characterized by having a concave cutting edge consisting of a concave curved part continuous with the shaped cutting edge. (2) The height H of the convex curved cutting edge with respect to the radius line is 0.0 when the gun drill diameter is D.
3D to 0.06D, and the width L where the convex curved cutting edge overlaps the radius line is 0.25D to 0.3
5D, and further characterized in that the angle that the inclined portion of the concave cutting edge makes with respect to the radius line is 5° to 30°. (3) The wall portion facing the rotation direction of the chip discharge groove is
The gun drill according to claim 1 or 2, which is a registered utility model, wherein the cross-sectional shape is the same as that of the cutting edge and extends from the distal end to the proximal end. (4) The wall portion facing the rotation direction of the chip discharge groove is
Its cross-sectional shape is the same as that of the cutting edge, and extends from the tip to the base end in the range of D/5 to 3.0D, and beyond that range, on the base end side, there is a chip discharge groove. Utility model registration claim 1 or 2, characterized in that the cross-sectional area of the convex curved surface continuous to the convex curved cutting edge gradually decreases toward the proximal end so that the cross-sectional area gradually increases. Gun drill as described in section. (5) The wall portion facing the rotation direction of the chip discharge groove is
Its cross-sectional shape is the same as that of the cutting edge, and extends from the tip to the base end in the range of D/5 to 3.0D, and beyond that range, on the base end side, there is a chip discharge groove. Utility model registration claim 1 or 2, characterized in that the wall portion continuous with the convex curved cutting edge is flat so that the cross-sectional area becomes large.
Gun drill as described in section.