EP0127009A1
Expired / Lapsed
EP
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Drill
Assignee: OFFERTA DI LICENZA AL PUBBLICO
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Filing: 1984-05-02
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Granted: —
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Expires: 2004-05-02
Abstract
Abstract A drill made of cemented carbide. To compensate for the brittleness of cemented carbide to increase its cross-break strength, the ratio of the diameter (c) of the web portion (1) to the drill diameter (d) is set in the range of 25% to 35%, and the flute width ratio (b : a) is set in the range of 0.4 : 1 to 0.8 : 1. Further, to decrease the cutting resistance on the drill, the radial rake (o,) angel of the cutting lip (4) measured at positions spaced at least 213 of the drill diameter toward the outer peripheral side is set in the range of -5° to positive. Furthermore, to promote the chip ejecting function, the relative distance (L) between the cutting lip (4) and the flute wall (5) opposed thereto is decreased.
Inventors
- 👤 Yoshikatsu Mori
- 👤 Yoshio Dohi
- 👤 Hideo Fukagawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 11:50
CPC Classifications
B; B23; B23B; B23B51/00; B23B51/02; B23B2250/00; B23B2250/12; B23B2251/00; B23B2251/18; B23B2251/182; B23B2251/24; B23B2251/241; B23B2251/40; B23B2251/406; Y; Y10; Y10T; Y10T408/00; Y10T408/44; Y10T408/45; Y10T408/455; Y10T408/78; Y10T408/89; Y10T408/909; Y10T408/9095; Y10T408/9097
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
181 words
A drill of superhard material wherein: the drill diameter d is set in the range of 25 % to 25 % and the flute width ration (b : a) is set in the range of 0.4 : 1 to 0.8 : 1, in an end view of the cutting end, the radial rake angel θ r of the cutting lip 4 taken at positions spaced at least 2/3 of the drill diameter toward the outer peripheral side is set at - 5° to positive, and the distance from a line perpendicular to a reference line ℓ connecting the outermost peripheral point of the cutting lip 4 as seen in the end view of the cutting end and a comparatively outwardly located point P 2 on the cutting lip 4 spaced 2/3 of the radius from the center 0, drawn at said outermost peripheral end point P 3 on the flute wall 5 opposed to said cutting lip 4 across the space of the flute 2 is set at not more than 47 % of the drill diameter d. (see Fig. 5)
Claim 2
Dependent Claim
181 words
A drill of superhard material wherein: the drill diameter d is set in the range of 25 % to 25 % and the flute width ration (b : a) is set in the range of 0.4 : 1 to 0.8 : 1, in an end view of the cutting end, the radial rake angel θ r of the cutting lip 4 taken at positions spaced at least 2/3 of the drill diameter toward the outer peripheral side is set at - 5° to positive, and the distance from a line perpendicular to a reference line ℓ connecting the outermost peripheral point of the cutting lip 4 as seen in the end view of the cutting end and a comparatively outwardly located point P 2 on the cutting lip 4 spaced 2/3 of the radius from the center 0, drawn at said outermost peripheral end point P 3 on the flute wall 5 opposed to said cutting lip 4 across the space of the flute 2 is set at not more than 47 % of the drill diameter d. (see Fig. 5)
Claim 3
Dependent Claim
55 words
A drill as set forth in Claim 1, wherein in said end view of the cutting end, the portion of the cutting lip 4 spaced at least 2/3 of the drill diameter d toward the outer peripheral side is arcuate so that its radial rake θ r angel can be set at 0° to positive.
Claim 4
Dependent Claim
34 words
A drill as set forth in Claim 1, wherein the portion 22 where the outer peripheral surface 20 of the margin 19 intersects the inner peripheral surface 21 of the flute 2 is chamfered.
Claim 5
Dependent Claim
28 words
A drill as set forth in Claim 3, wherein said chamfered portion 22 is an inclined plane obliquely intersects the outer peripheral surface 20 of said margin 19.
Claim 6
Dependent Claim
31 words
A drill as set forth in Claim 4, wherein said inclined plane has a width which is in the range of 2 % to 5 % of the drill diameter d.
Claim 7
Dependent Claim
18 words
A drill as set forth in Claim 3, wherein said chamfered portion 22 has a rounded curved surface.
Claim 8
Dependent Claim
34 words
A drill as set forth in Claim 6, wherein the rounded curved surface has a radius of curvature which is in the range of 0.3 % to 1.5 % of the drill diameter d.
Claim 9
Dependent Claim
59 words
A drill as set forth in Claim 3, wherein the portion where outer relief surface 23 of the land 3 intersects the inner peripheral surface 21 of the flute 2 is a flat chamfered portion 24 whose radius of curvature is in the range of 0.05 mm to 0.5 mm or which intersects said respective surfaces at obtuse angles.
Claim 10
Dependent Claim
148 words
A drill as set forth in Claim 1, wherein: the configuration of said web portion 1 formed by thinning is such that the chisel width is in the range of 0 mm to 0.4 mm, and in said end view of the cutting end, the cutting lips 8,8 radially outwardly extending from the axial center 0 of said web portion 1 are each linearly formed, and the angle θ 1 formed between the direction in which the cutting lip 8 of said web portion 1 extends and the direction extending from said axial center to the outermost peripheral end of the cutting lip 4 extending to the outer peripheral side of the drill from the radial outermost end P 4 of the cutting lip 8 of said web portion 1, where these directions intersect each other, is set in the range of 35° to 45°. (see Fig. 5)
Claim 11
Dependent Claim
93 words
A drill as set forth in Claim 9, wherein the rake surface 9 of said web portion 1 formed by thinning has its axial rake angle θ 2 set in the range of - 5° to + 5°, the axial length being 0 mm at the axial center 0 of the drill, and the valley line 12 defined by said rake surface 9 intersecting the adjacent ground surface 10 formed concurrently therewith by thinning has an angle θ 3 of inclination in the range of 25° to 60°. (see Figs. 6 and 7)
Claim 12
Dependent Claim
84 words
A drill as set forth in Claim 10, wherein the angle formed between the rake surface 9 of said web portion 1 and said adjacent ground surface 10 is in the range of 90° to 110°, and as the portion along said valley line 12, the cross-section of the boundary region passing from the rake surface 9 of said web portion 1 to said adjacent ground surface 10 forms an arc whose radius of curvature.is in the range of 0.3 mm to 1.0 mm.
Claim 13
Dependent Claim
80 words
A drill as set forth in Claim 9, wherein all of the cutting lips including those of said web portion 1 are each formed with a chamfered portion 18 in the form of either an are having a radius of curvature in the range of 0.03 mm to 0.2 mm or a slope having a width in the range of 0.05 mm to 0.2 mm and forming an angle in the range of 0° to 30° with the rake surface.
Claim 14
Dependent Claim
24 words
A drill as set forth in Claim 1, wherein each of the widthwise opposite ends of the land portion 3 has a margin 19.
Claim 15
Dependent Claim
40 words
A drill as set forth in Claim 1, wherein the shank 13 extending from the rear end to the front end of said drill and the land portions 3 of the main body are internally formed with oiling holes 14.
Claim 16
Dependent Claim
15 words
A drill as set forth in Claim 1, wherein said superhard material is cemented carbide.
Claim 17
Dependent Claim
16 words
A drill as set forth in Claim 1, wherein said superhard material is high speed steel.
Claim 18
Dependent Claim
59 words
,A drill as set forth in Claim 1, wherein part of the surface of the main body of the drill including at least the cutting lips 4, 8 or all said surface is coated with one or a combination of two or more elements selected form the group consisting of TiC, TiCN, TiN, and Al 2 O 3 .
Claim 19
Dependent Claim
37 words
A drill as set forth in Claim 17, wherein part of said surface including at least the cutting lips 4, 8 includes at least the rake surface and the outer peripheral surface 20 of the margin 19.
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