Multi-purpose drilling tool

• US 7,401,667 B2
• Filed: 11/12/2004
• Issued: 07/22/2008
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Duscha, Helmut, Haussmann, August
• Primary Examiner(s): Neuder; William P
• Application Number:
  US10/558,962
• Publication Number:
  US 20060243495A1
• Time in Patent Office: 1,348 Days
• Field of Search: 175/323, 175/415, 175/420.1, 175/426, 408/230
• US Class Current: 175/323
• CPC Class Codes: B23B 2222/28 Details of hard metal, i.e. cemented carbide
• CPC Class Codes: B23B 2222/56 Non-specified metals
• CPC Class Codes: B23B 2226/18 Ceramic
• CPC Class Codes: B23B 2226/315 polycrystalline [PCD]
• CPC Class Codes: B23B 2226/61 Plastics not otherwise provided for, e.g. nylon
• CPC Class Codes: B23B 2226/75 Stone, rock or concrete working of stone B28D
• CPC Class Codes: B23B 2251/04 Angles, e.g. cutting angles
• CPC Class Codes: B23B 2251/14 Configuration of the cutting part, i.e. the main cutting edges
• CPC Class Codes: B23B 2251/50 Drilling tools comprising cutting inserts
• CPC Class Codes: B23B 51/02 Twist drills
• CPC Class Codes: Y10T 408/9097 Spiral channel

Abstract

The present invention relates to a multi-purpose drilling tool with a boring head, a drill twist connected thereto and a downstream clamping shank, a cutting element (1) being provided on the working side of the boring head. The cutting element (1) has a face (9, 24) with a rake angle (γ) having a value of γ≧0° b, the cutting element (1) having a flank (10, 13) with a lip clearance angle (α) having a value of 5°≦α≦15° and, in particular, α≈10°.

Claims

1. A multi-purpose drilling tool (27) with a boring head (28), a drill twist (29) connected thereto and a downstream clamping shank (30), a cutting element (1) being provided on the working side of the boring head (28), wherein the cutting element (1) has a face (9, 24), at least a portion of the face (9, 24) having a rake angle (γ

) with a value of γ

=0° and

with a leading edge (25) extending parallel to a longitudinal drill bit axis (2), and a lateral surface (16,17),

wherein the cutting element (1) has at least one flank (10, 13) with a lip clearance angle (α

) having a value of 5°

≦

α

≦

15°

,

wherein the cutting element (1) is limited laterally by two longitudinal sides (5, 6) and two transverse sides (7, 8),

wherein a cutting lip (3) of cutting element (1) tapers from the transverse side (7) toward the longitudinal drill bit axis (2) from a width (SH) to a width (SQ),

wherein the cutting element (1) has at least one cutting edge (11, 12) formed by the face (9, 24) and the flanks (10, 13),

wherein the flanks (10, 13) meet at a chisel edge (14), said chisel edge (14) also joining the cutting edges (11, 12), and

wherein the face (9) extends toward a plane (E16) of the lateral surface (16) at an acute taper angle (λ

).

2. The multi-purpose drilling tool (27) as recited in claim 1, wherein the cutting edge (11, 12) is directed toward the longitudinal drill bit axis (2).

3. The multi-purpose drilling tool (27) as recited in claim 2, wherein the cutting edge (11, 12) has a shape that is selected from a curve, a zigzag, or both and approaches the longitudinal drill bit axis (2) or the longitudinal mid-plane (EYZ).

4. The multi-purpose drilling tool (27) as recited in claim 2, wherein the cutting edges (11, 12) meet to form a point angle (R) of 100°

to 150°

.

5. The multi-purpose drilling tool (27) as recited in claim 1, wherein the face (9, 24) forms an acute taper angle (λ

) with a longitudinal mid-plane (EYZ) and transitions via a curved surface (19) into the lateral surface (16, 17).

6. The multi-purpose drilling tool (27) as recited in claim 1, wherein the lateral surface (16, 17) and the face (9, 24) meet at a straight transition edge (SS, SSB), the transition edge (SS;

SSB) extending in parallel with or at an acute angle with a longitudinal drill bit axis (2).

7. The multi-purpose drilling tool (27) as recited in claim 2, wherein the cutting edge (11, 12) has an extension (15, 23) that transitions into the lateral surface (16, 17) on the other side of a transversal mid-plane (EXZ).

8. The multi-purpose drilling tool (27) as recited in claim 1, wherein the cutting element (1) is designed as a hard-metal cutting element.

9. The multi-purpose drilling tool (27) as recited in claim 1, wherein the face (9, 24) is designed as a flat surface and has a uniform rake angle (γ

).

10. The multi-purpose drilling tool (27) as recited in claim 1, wherein the face (9, 24) has a first partial face (9a, 24a) with a rake angle γ

≧

0° and

a second partial face (9b, 24b) with a negative rake angle γ

<

0°

.

11. The multi-purpose drilling tool (27) as recited in claim 1, wherein the face (9, 24) has a negative rake angle γ

<

0°

close to the longitudinal drill bit axis (2).

12. The multi-purpose drilling tool (27) as recited in claim 1, wherein the face (9, 24) has a rake angle γ

>

0°

oriented toward transverse sides (7, 8).

13. The multi-purpose drilling tool (27) as recited in claim 1, wherein the multi-purpose drilling tool (27) is usable in a rotating and rotary-impacting manner.