Drill Ring for a Core Drill Bit and Method for Producing a Drill Ring

Abstract

A method for producing a drill ring for a core drill bit is disclosed. The method includes constructing at least two green parts from encapsulated diamond particles, the diamond particles being covered by a powder mixture. The green parts are formed into ring segments under the effect of pressure and the ring segments are annularly assembled and sintered under temperature action to form a continuous drill ring.

Claims

1.-17. (canceled)

18. A drill ring for a core drill bit, comprising: at least two ring segments constructed from a sintered powder mixture and diamond particles; wherein the at least two ring segments are connected to each other at respective side edges.

19. The drill ring according to claim 18, wherein the drill ring includes n≧1 first ring segments and n second ring segments and wherein the first and the second ring segments are disposed alternately one behind the other along a circumferential direction of the drill ring.

20. The drill ring according to claim 19, wherein the first ring segments are constructed from a sintered first powder mixture and first diamond particles and wherein the second ring segments are constructed from a sintered second powder mixture and second diamond particles.

21. The drill ring according to claim 20, wherein the sintered first powder mixture and the sintered second powder mixture are identical.

22. The drill ring according to claim 20, wherein the first diamond particles and the second diamond particles have a same diamond distribution and a same mean diamond diameter.

23. The drill ring according to claim 18, wherein at least one water slot is disposed between the at least two ring segments.

24. The drill ring according to claim 23, wherein the at least one water slot extends between ⅓ and ⅚ of a total height of the drill ring.

25. The drill ring according to claim 18, wherein the at least two ring segments have a bore that connects an inner side of the drill ring to an outer side of the drill ring.

26. A method of manufacturing a drill ring for a core drill bit, comprising the steps of: constructing at least two green parts from diamond particles that are enveloped by a powder mixture; forming the at least two green parts into respective ring segments under pressure; and annularly assembling the ring segments and sintering the ring segments under temperature action to form a continuous drill ring.

27. The method according to claim 26, wherein the continuous drill ring includes n≧1 first green parts which are formed into first ring segments and n second green parts which are formed into second ring segments and wherein the first and the second ring segments are disposed alternately one behind the other along a circumferential direction of the continuous drill ring.

28. The method according to claim 27, wherein the first green parts include a first powder mixture and first diamond particles and wherein the second green parts include a second powder mixture and second diamond p articles.

29. The method according to claim 26, wherein the continuous drill ring includes n≧2 equal green parts and wherein the green parts are disposed alternately one behind the other along a circumferential direction of the continuous drill ring.

30. The method according to claim 26, wherein the at least two green parts are constructed with rectangular base surfaces.

31. The method according to claim 26, wherein the at least two green parts are constructed with pentagonal base surfaces and wherein the pentagonal base surfaces have a rectangle and a trapezoid with two right interior angles.

32. The method according to claim 26, wherein the at least two green parts are constructed with hexagonal base surfaces and wherein the hexagonal base surfaces have a rectangle and an isosceles trapezoid.

33. The method according to claim 26, wherein the ring segments are subjected to pressure action during the sintering.

34. The method according to claim 33, wherein the ring segments are subjected to external shaping by the pressure action during the sintering.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 illustrates a core drill bit consisting of a drill ring, a cylindrical drill shaft and a receiving segment;

[0035] FIG. 2 illustrates a drill ring according to the invention with four ring segments and four water slots between the ring portions;

[0036] FIGS. 3A-D illustrate the production of the drill ring of FIG. 2 of first and second green parts with a hexagonal base surface (FIG. 3A), wherein the green parts are formed into first and second ring segments (FIG. 3B), the ring segments are arranged alternately one behind the other (FIG. 3C) and sintered to a continuous drill ring (FIG. 3D); and

[0037] FIGS. 4A-C illustrate green parts with a rectangular base surface (FIG. 4A), a pentagonal base surface (FIG. 4B) and a hexagonal base surface (FIG. 4C).

DETAILED DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 shows a core drill bit 10 with a drill ring 11, a cylindrical drill shaft 12 and a receiving segment 13 with an insertion end 14. The core drill bit 10 is fastened via the insertion end 14 in the tool receptacle of a core drilling device and during drilling operation is driven by the core drilling device in a rotary direction 15 about a rotary axis 16, wherein the axis of rotation 16 is coaxial with the cylinder axis of the core drill bit 10.

[0039] The drill ring 11 is welded, brazed, or screwed to the drill shaft 12, or fixed to the drill shaft 12 in another suitable manner of attachment. In order to be able to weld the drill ring 11 with the drill shaft 12, the connecting area between the drill ring 11 and the drill shaft 12 must be made of a weldable material and must not contain diamonds, as diamonds cannot be welded.

[0040] FIG. 2 shows a first embodiment of a drill ring 21 according to the invention, composed of four ring segments. The ring segments can be divided into two first ring segments 22.1, 22.2 and two second ring segments 23.1, 23.2 which are arranged alternately one behind the other along a circumferential direction of the drill ring 21. The first ring segments 22.1, 22.2 consist of a first powder mixture 24 and first diamond particles 25, and the second ring segments 23.1, 23.2 consist of a second powder mixture 26 and second diamond particles 27.

[0041] Four water slots 28.1, 28.2, 28.3, 28.4 are formed between the ring segments 22.1, 23.1, 22.2, 23.2, via which a cooling liquid is transported to the processing site. The water slots 28.1-28.4 extend over a height of approximately ⅔ of the total height of the drill ring 21. In order to ensure the operational capability of the drill ring 21 even if the water slots 28.1-28.4 are removed, the drill ring 21 additionally has two bores 29.1, 29.2, via which cooling liquid is transported to the processing site.

[0042] FIGS. 3A-D show the fabrication of the drill ring 21 of FIG. 2 from two first green parts 31 and two second green parts 32 (FIG. 3A), which are formed into the first ring segments 22.1, 22.2 and second ring segments 23.1, 23.2 (FIG. 3B). The ring segments are alternately arranged one behind the other along the circumferential direction of the drill ring 21 (FIG. 3C) and sintered under temperature and pressure action to form a continuous drill ring (FIG. 4D).

[0043] FIG. 3A shows the first green part 31, which is constructed of the first powder mixture 24 and the first diamond particles 25, and the second green part 32, which is constructed of the second powder mixture 26 and the second diamond particles 27. The first diamond particles 25 are enveloped by the first powder mixture 24 and form first encapsulated diamond particles 33 and the second diamond particles 27 are enveloped by the second powder mixture 26 and form second encapsulated diamond particles 34. The base surface of the green parts 31, 32 is hexagonal and consists of a rectangle 35 and an adjacent isosceles trapezoid 36. In the region of the legs of the trapezoid, the water slots 28.1-28.4 are formed during sintering by additional pressure action, via which the cooling liquid is transported to the processing site.

[0044] FIG. 3B shows the first ring segment 22, which was created from the first green part 31 of FIG. 3A under pressure action, and the second ring segment 23 consisting of the second green part 32 of FIG. 3A under pressure action. The inner sides 37 of the ring segments 22, 23 have a concave curvature, while the opposite outer sides 38 have a convex curvature.

[0045] The first ring segment 22 has first and second side edges 41, 42 which are joined to a first and second side edge 43, 44 of the second ring segment 23 during sintering. The first side edge 41 of the first ring segment 22 is connected to the second side edge 44 of the second ring segment 23, and the second side edge 42 of the first ring segment 22 is connected to the first side edge 43 of the second ring segment 23. In the drill ring 21 with two first and second ring segments 22.1, 22.2, 23.1, 23.2, the first and second side edges of the adjacent ring segments are connected to each other.

[0046] FIG. 3C shows the first and second ring segments 22.1, 22.2, 23.1, 23.2 arranged one behind the other along the circumferential direction of the drill ring 21 and adjoining one another with the side edges 41, 42, 43, 44. The ring segments 22.1, 23.1, 22.2, 23.2 form a continuous drill ring and, in the arrangement shown in FIG. 3C, processed further in a hot press.

[0047] FIG. 3D shows the drill ring after the hot pressing. During hot pressing, the ring segments 22.1, 23.1, 22.2, 23.2 are subjected to temperature and pressure action. The temperature action ensures that the powder mixture 24, 26 is sintered in the ring segments and the ring segments 22.1, 23.1, 22.2, 23.2 are connected to one another at the side edges 41, 42, 43, 44. Pressure in the axial direction causes compression of the ring segments, which leads to densification of the ring segments. Hot pressing is carried out in a die which defines the final shape of the drill ring 21.

[0048] In the method according to the invention, a drill ring is constructed from a plurality of green parts, which are formed into ring segments and are sintered to form a continuous drill ring; polygonal base surfaces are a suitable geometry for the green parts. FIGS. 4A-C show green parts 51 with a rectangular base surface (FIG. 4A), green parts 52 with a pentagonal base surface (FIG. 4B) and green parts 53 with a hexagonal base surface (FIG. 4C).

[0049] The rectangular base surface 54 of the green parts 51 represents the simplest geometry for producing drill rings from a plurality of ring segments. In the exemplary embodiment of FIG. 4A, three identical green parts 51.1, 51.2, 51.3 are used to produce a continuous drill ring.

[0050] The pentagonal base surface of the green parts 52 can be divided into a rectangle 55 and a trapezoid 56 with two right interior angles. In the region of the inclined leg of the trapezoid, a water slot 57 is produced during sintering with the adjacent ring segment. A number of n water slots 57 are produced with such a pentagonal base surface for a drill ring with 2n, n≧1 ring segments.

[0051] The hexagonal base surface of the green parts 53 can be divided into a rectangle 58 and an isosceles trapezoid 59. In the region of the inclined trapezoidal legs, water slots 60 are produced during sintering with the adjacent ring segments. With such a hexagonal base surface, a number of n water slots 60 are generated in a drill ring with n, n≧2 ring segments.