A drill tool

Abstract

This invention discloses a drilling tool, comprising a tool body symmetrical about a central axis. The front end of the tool body has a core holder and a peripheral holder. The periphery of the tool body has a core chip groove and a peripheral chip groove. The core chip groove extends from the core holder to the rear end of the tool body, and the peripheral chip groove extends from the peripheral holder to the rear end of the tool body. The peripheral chip groove has a concave cross-section perpendicular to the central axis. The concave cross-section includes a concave bottom surface and a right side surface and a left side surface connecting the two ends of the concave bottom surface. The concave bottom surface has a bottom protrusion protruding towards the opening of the concave cross-section. The right side surface and the left side surface each have a right stepped surface and a left stepped surface, respectively. The side of the right stepped surface and the left stepped surface facing the concave bottom surface is solid. This drilling tool has the advantages of improving chip removal capacity and efficiency, as well as increasing overall strength.

Claims

1. A drilling tool, comprising a tool body (1) symmetrical about a central axis (3), wherein the front end of the tool body (1) is provided with a core holder (4) and a peripheral holder (5), and the periphery of the tool body (1) is provided with a core chip groove (6) and a peripheral chip groove (7), wherein the core chip groove (6) extends from the core holder (4) to the tail end of the tool body (1), and the peripheral chip groove (7) extends from the peripheral holder (5) to the tail end of the tool body (1), wherein the peripheral chip groove (7) has a circumferential concave cross section (8) perpendicular to the central axis (3), characterized in that: The circumferential concave cross-section (8) includes a circumferential concave bottom surface (71), a right side surface (72) and a left side surface (73) respectively connecting both ends of the circumferential concave bottom surface (71). The circumferential concave bottom surface (71) has a bottom protrusion portion protruding towards the opening direction of the circumferential concave cross-section (8). The right side surface (72) and the left side surface (73) are respectively provided with a right stepped surface (723) and a left stepped surface (733). The sides of the right stepped surface (723) and the left stepped surface (733) facing the circumferential concave bottom surface (71) are solid bodies.

2. The drilling tool according to claim 1, characterized in that: The right side surface (72) includes a first lower side surface (721) and a first upper side surface (722). One end of the first lower side surface (721) is connected to the circumferential concave bottom surface (71), and the other end is connected to the first upper side surface (722) through the right stepped surface (723). The left side surface (73) includes a second lower side surface (731) and a second upper side surface (732). One end of the second lower side surface (731) is connected to the circumferential concave bottom surface (71), and the other end is connected to the second upper side surface (732) through the left stepped surface (733). The included angle between the first lower side surface (721) and the second lower side surface (731) is α1, and the included angle between the first upper side surface (722) and the second upper side surface (732) is α2, and it should satisfy 50 ≤ α1 ≤ α2 ≤ 140°.

3. The drilling tool according to claim 2, characterized in that: The length of the first lower side surface (721) is L1, and the length of the second lower side surface (731) is L2, and it should satisfy: 0.1D < L1, L2 < 0.4D, where D is the diameter of the tool body (1).

4. The drilling tool according to claim 2, characterized in that: The right stepped surface (723) is an arc surface with a radius of r1 or an inclined surface with a length of P1, satisfying: 0.02D ≤ r1, P1 ≤ 0.1D; the left stepped surface (733) is an arc surface with a radius of r2 or an inclined surface with a length of P2, satisfying: 0.02D ≤ r2, P2 ≤ 0.1D.

5. The drilling tool according to claim 1, characterized in that: The protrusion height of the bottom protrusion portion relative to the central axis (3) is H, satisfying: 0.15D ≤ H ≤ 0.18D.

6. The drilling tool according to claim 1, characterized in that: The diameter of the tool body (1) is D, and the width of the circumferential concave bottom surface (71) is W, satisfying: 0.25D ≤ W ≤ 0.45D.

7. The drilling tool according to claim 1, characterized in that: The core chip groove (6) has a core concave cross-section (9) perpendicular to the central axis (3), and the core concave cross-section (9) is U-shaped; the core tool seat (4) is equipped with a core cutting blade (41), and the peripheral tool seat (5) is equipped with a peripheral cutting blade (51).

8. The drilling tool according to any one of claims 1 to 7, characterized in that: The circumferential concave bottom surface (71) is triangular or serrated.

9. The drilling tool according to claim 8, characterized in that: The included angle between the two side surfaces of the bottom protrusion portion is β, satisfying: 80° ≤ β ≤ 160°.

10. The drilling tool according to any one of claims 1 to 7, characterized in that: The bottom protrusion portion is arc-shaped, and the protrusion height of the bottom protrusion portion relative to the central axis (3) is H', satisfying: 0.15D ≤ H' ≤ 0.18D.

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