초록 ▼

An indexable insert for solid drills has four identical cutting edges (30) arranged at a distance above a supporting base (42) and each extending between two cutting-edge corners (28′, 28′). The cutting edges are each bounded by a cutting face (46) and a clearance face (48), with the inclusion of a

An indexable insert for solid drills has four identical cutting edges (30) arranged at a distance above a supporting base (42) and each extending between two cutting-edge corners (28′, 28′). The cutting edges are each bounded by a cutting face (46) and a clearance face (48), with the inclusion of a wedge angle (b). Of the cutting edges (30), one in each case is in an active operating position during the drilling operation. To permit optimum adaptation to the cutting conditions and drilling characteristics, varying over the length of the cutting edge of the drilling tool, it is proposed according to the invention that the height (h) of the four cutting edges (30), measured from the plane of the supporting base (42), and/or the clearance angle (a) varies over the length of the respective cutting edges (30).

대표청구항 ▼

1. An indexable insert for solid drills, having a supporting base (42), having four lateral supporting surfaces (44) projecting beyond the supporting base, and having four identical cutting edges (30) which are arranged at a distance above the supporting base (42), extend between in each case two cu

1. An indexable insert for solid drills, having a supporting base (42), having four lateral supporting surfaces (44) projecting beyond the supporting base, and having four identical cutting edges (30) which are arranged at a distance above the supporting base (42), extend between in each case two cutting-edge corners (28, 28″), are bounded by a respective tool face (46) and a tool flank (48) and of which in each case one is located in an active use position during the drilling operation, in the case of which the tool flank (48), at each point of the associated cutting edge (30), encloses a clearance angle (α) with a straight line (52) perpendicular to the supporting base (42), the clearance angle (α) varying along the cutting edge (30), characterized in that the clearance angle (α) increases from a relatively small value in the region of the cutting-edge corner (28′) to a maximum value and decreases over the rest of the cutting edge (30) as far as the other cutting-edge corner (28″), and in that the increase in the angle values from small to maximum value from one of the cutting-edge corners (28″) is more pronounced than from the other cutting-edge corner (28′). 2. The indexable insert as claimed in claim 1, characterized in that the cutting edge (30) is rounded in the region of the cutting-edge corners (28′, 28″), and in that the clearance angle (α) varies over the course of the cutting-edge corner. 3. The indexable insert as claimed in claim 1, characterized in that the cutting-edge portion (54) with maximum clearance angle (α) is arranged outside the cutting-edge center. 4. The indexable insert as claimed in claim 1, characterized in that the clearance angle (α) assumes its maximum value along an elongate cutting-edge portion (54). 5. The indexable insert as claimed in claim 1, characterized in that the wedge angle (β) enclosed along the cutting edge (30) between the tool face (46) and tool flank (48) varies along the cutting edge (30). 6. The indexable insert as claimed in claim 5, characterized in that the wedge angle (β) in the cutting-edge portion (54) of maximum cutting-edge height (h) and/or maximum clearance angle (α) is smaller than in the region of the cutting-edge corners (28′, 28″). 7. The indexable insert as claimed in claim 1, characterized in that the height (h) of the cutting edges (30), as measured from the plane of the supporting base (42), varies over the length of the cutting edges. 8. The indexable insert as claimed in claim 7, characterized in that the height (h) of the cutting edges (30), as measured from the plane of the supporting base (42), ascends from one cutting-edge corner (28′) en route to a cutting-edge portion (54) of maximum height (h) and decreases as the other cutting-edge corner (28″) is approached. 9. The indexable insert as claimed in claim 8, characterized in that the height profile of the cutting edges (30) between the two cutting-edge corners (28′, 28″) is asymmetrical. 10. The indexable insert as claimed in claim 8, characterized in that the cutting-edge portion (54) of maximum height (h) is displaced in the direction of one of the two cutting-edge corners. 11. The indexable insert as claimed in claim 7, characterized in that the ascents of each cutting edge (30) from the cutting-edge corners (28′, 28″) to the cutting-edge portion (54) of maximum height (h) are non-linear. 12. The indexable insert as claimed in claim 7, characterized in that the ascent of each cutting edge (30) from the one cutting-edge corner (28″) is steeper than from the other cutting-edge corner (28′). 13. The indexable insert as claimed in claim 7, characterized in that the ascent portions (56′, 56″) of the cutting edge (30) are connected to one another via an elongate cutting-edge portion (54) of maximum height. 14. The indexable insert as claimed in claim 1, characterized in that the clearance angle (α) and/or the cutting-edge height (h) vary/varies in a wave-like manner along the cutting edge (30). 15. The indexable insert as claimed in claim 14, characterized in that in each case at least two variation waves are provided along the cutting edge (30). 16. The indexable insert as claimed in claim 1, characterized in that the supporting surfaces (44) are formed, at least in part, by the tool flanks (48) of the associated non-active cutting edges (30). 17. The indexable insert as claimed in claim 16, characterized in that the supporting surfaces (44) are connected to the supporting base (42) via a pyramidally tapering transition portion (58). 18. The indexable insert as claimed in claim 16, characterized in that the supporting base (42) has a square outline. 19. The indexable insert as claimed in claim 16, characterized in that the supporting surfaces (44) bound a cuboid or a truncated pyramid with a square surface area. 20. The indexable insert as claimed in claim 1, characterized in that the supporting surfaces (44) together with the supporting base (42) form a supporting portion (64), while the tool flanks (48) with the cutting edges (30) and the tool faces (46) form a cutting portion (62), which is connected to the supporting portion (64) via a preferably pyramidal transition portion (66). 21. The indexable insert as claimed in claim 1 as an outer insert (22) of a solid drill having at least two radially and circumferentially spaced-apart insert seats (36) which partially overlap in the radial direction. 22. An inner insert (20) of a solid drill having at least two radially and circumferentially spaced-apart insert seats (36), which partially overlap in the radial direction, comprising an indexable insert for solid drills, having a supporting base (42), having four lateral supporting surfaces (44) projecting beyond the supporting base, and having four identical cutting edges (30) which are arranged at a distance above the supporting base (42), extend between in each case two cutting-edge corners (28, 28″), are bounded by a respective tool face (46) and a tool flank (48) and of which in each case one is located in an active use position during the drilling operation, in the case of which the tool flank (48), at each point of the associated cutting edge (30), encloses a clearance angle (α) with a straight line (52) perpendicular to the supporting base (42), the clearance angle (α) varying along the cutting edge (30), characterized in that the clearance angle (α) increases from a relatively small value in the region of the cutting-edge corner (28′) to a maximum value and decreases over the rest of the cutting edge (30) as far as the other cutting-edge corner (28″), and in that the increase in the angle values from small to maximum value from one of the cutting-edge corners (28″) is more pronounced than from the other cutting-edge corner (28′).