Cutting edge replaceable drill

Abstract

To provide a cutting edge replaceable drill capable of improving biting performance on a work material and suppressing whirling of the drill itself in a state where the cutting edge strength of a cutting edge is maintained.SOLUTION: A cutting edge replaceable drill 10 comprises: a cutting edge component provided with two or more cutting blades constructed outward from a center axis O; and a shaft body component provided with two or more twist grooves 9, 9 corresponding to the number of cutting blades. The cutting places 1 and 2 of the cutting edge component are formed by a first cutting blade 1, 1 adjacent to thinning surface 3, 3 and extending from a chisel edge 4 to outside the cutting edge replaceable drill 10 and a second cutting blade 2, 2 linearly extending from the end of the first cutting blade 1, 1 to outside the cutting edge replaceable drill 10. The relief angle of the first cutting blade 1, 1 is set within the range of 8°-25°, and the relief angle of the second cutting blade 2, 2 is similar to that of the first cutting blade 1, 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an indexable drill for drilling holes on the surface of a tool. [Background technology]

[0002] Conventional drills, especially replaceable-tip drills in which the cutting edge and main body (shank) are separate, can be classified into fixed types in which the cutting edge is fixed by screwing it onto the main body, and latching types in which the cutting edge is fixed by screwing it onto the tip of the main body (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7203841 [Patent Document 2] Patent No. 7231305 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with both of these fastening methods, the tool gradually loosens over time, affecting the accuracy of the drilled hole. In particular, with the aforementioned latching method, where the cutting edge is fastened to the main body, it is not possible to prevent loosening by tightening the screw, as is the case with the screw fastening method.

[0005] Furthermore, if the cutting edge is not worn, replacing the cutting edge due to a problem with only the fastening part is inefficient, and it is also difficult to establish a standard for determining when to replace it. Drill runout during drilling can lead to a decrease in hole diameter accuracy and damage to the drill head and drill body due to breakage. Increasing the drill's clearance angle can reduce drill runout, but this also reduces contact with the workpiece and suppresses wear on the cutting edge. However, this also creates a new problem of reduced cutting edge strength.

[0006] Therefore, an object of the present invention is to provide an indexable drill that can improve the biting ability into the workpiece while maintaining the strength of the cutting edge and suppress the whirling of the drill itself. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the indexable drill of the present invention is an indexable drill that includes a cutting edge component with two or more cutting edges extending outward from a central axis, and a shaft component with two or more spiral flutes and a shank corresponding to the number of these cutting edges, and these cutting edges are formed from a first cutting edge that extends outward from the chisel edge adjacent to the thinning surface, and a second cutting edge that extends linearly from the end of the first cutting edge outward from the indexable drill.

[0008] The clearance angle of the first cutting edge is set to a range of 8° to 25°, and the clearance angle of the second cutting edge 2 is set to the same as the clearance angle of the first cutting edge. The clearance angle of the first cutting edge 1 may be set to a range of 22° to 25°. [Effects of the Invention]

[0009] The indexable drill of the present invention has the effect of improving the biting ability into the workpiece while maintaining the strength of the cutting edge, and suppressing the whirling of the drill itself. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a front view of an indexable drill 10 according to the present invention; [Figure 2] XX line cross-sectional view of the indexable drill 10 shown in FIG. [Figure 3] 1. A cross-sectional view of the indexable drill 10 taken along line YY in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] FIG. 1 shows a front view of an indexable drill 10 according to one embodiment of the present invention, FIG. 2 shows a cross-sectional view of the indexable drill 10 shown in FIG. 1 along line XX, and FIG. 3 shows a cross-sectional view of the indexable drill 10 shown in FIG. 1 along line YY.

[0012] 1, the indexable drill 10 according to the present invention has a first cutting edge 1 extending from the end of the chisel edge 4 outward (radially) from the center axis O of the indexable drill 10, and a second cutting edge 2 extending from the end of the first cutting edge 1 toward the outer corner of the indexable drill 10. The first cutting edge 1, the second cutting edge 2, and the clearance angles of each cutting edge (first clearance angle θ1, second clearance angle θ2) will be described in detail below.

[0013] <First cutting edge 1> The first cutting edge 1, which forms part of the indexable drill 10 of the present invention, is a cutting edge that extends radially from the end of the chisel edge 4 as shown in Fig. 1, and is also called a thinning cutting edge because it is adjacent to the thinning surface 3 (first rake face 7) of the indexable drill 10. In addition, the flank (first flank 5) and rake face (first rake face 7) adjacent to the first cutting edge 1 are formed separately from the flank and rake face adjacent to the second cutting edge 2 described below.

[0014] ≪Second cutting edge 2≫ The second cutting edge 2, which forms part of the indexable drill 10 of the present invention, is a cutting edge that extends linearly from the end of the first cutting edge 1 toward the outer corner as shown in Figure 1, and is also called the main cutting edge. The flank (second flank 6) and rake face (second rake face 8) adjacent to the second cutting edge 2 are formed separately from the flank and rake face adjacent to the first cutting edge 1.

[0015] <First clearance angle θ1> 1 and 2, the first clearance angle θ1 is the clearance angle of the first cutting edge 1 described above, i.e., the angle formed between the first clearance surface 5 and an imaginary line L1 perpendicular to the central axis O of the drill 10. This first clearance angle θ1 is in the range of 8° to 25°. Preferably, the first clearance angle θ1 can be in the range of 22° to 25°.

[0016] <Second clearance angle θ2> 1 and 3, the second clearance angle θ2 is the clearance angle of the second cutting edge 2 described above, i.e., the angle between the second clearance surface 6 and an imaginary line L2 perpendicular to the central axis O of the drill 10. This second clearance angle θ2 is in the same range as the first clearance angle θ1 described above, that is, 8° to 25°. In other words, the first clearance angle θ1 of the first cutting edge 1 and the second clearance angle θ2 of the second cutting edge 2 are the same angle. By setting these two angles to the same value, the indexable cutting edge drill of the present invention can improve the biting ability into the workpiece while maintaining the cutting edge strength, and can suppress runout of the drill itself. [Explanation of symbols]

[0017] 1 First cutting edge 2 Second cutting edge 3 Thinning surface 4 Chisel Edge 5 First flank 6 Second flank 7 First rake face 8 Second rake face 9 Twisted groove 10 Indexable drill L1, L2 Imaginary lines perpendicular to the center axis of the drill O center axis θ1 First clearance angle θ2 Second clearance angle

Claims

1. An indexable drill having a cutting edge component with two or more cutting edges formed outward from a central axis, and a shaft component with two or more helical flutes and a shank corresponding to the number of cutting edges, wherein the cutting edges comprise a first cutting edge adjacent to a thinning surface and extending from a chisel edge outward from the indexable drill, and a second cutting edge extending in a straight line from an end of the first cutting edge outward from the indexable drill, wherein a first relief angle of the first cutting edge is in the range of 8° to 25°, and a second relief angle of the second cutting edge is the same as the first relief angle of the first cutting edge.

2. 2. The indexable drill according to claim 1, wherein the first relief angle of the first cutting edge is in the range of 22° to 25°.

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