CN114789272B

CN114789272B - Drilling tool

Info

Publication number: CN114789272B
Application number: CN202210637847.5A
Authority: CN
Inventors: 江爱胜; 吴火飞; 刘伟; 余仁超
Original assignee: Zhuzhou Cemented Carbide Cutting Tools Co Ltd
Current assignee: Zhuzhou Cemented Carbide Cutting Tools Co Ltd
Priority date: 2022-06-07
Filing date: 2022-06-07
Publication date: 2023-12-22
Anticipated expiration: 2042-06-07
Also published as: CN114789272A

Abstract

The invention discloses a drilling tool, which comprises a tool body and a cutting blade, wherein the tool body comprises a clamping handle part, a cutting end part and a tool body peripheral surface positioned between the clamping handle part and the cutting end part, the clamping handle part and the tool body peripheral surface are symmetrical relative to a rotation central axis of the cutting tool body, chip flutes are formed on the tool body peripheral surface, the cutting end part is provided with a tool flute communicated with the chip flutes, the cutting blade is fixedly arranged in the tool flute, the chip flutes comprise concave surfaces, and the bottom surfaces of the concave surfaces are of an arch structure outwards.

Description

Drilling tool

Technical Field

The invention mainly relates to the field of metal cutting machining, in particular to a drilling tool.

Background

Because the hard alloy materials are scarce, expensive and difficult to process, the use cost of the integral hard alloy drilling tool is high, the application of the integral hard alloy drilling tool is limited, and along with the improvement of the assembly technology, a split type drilling tool is appeared, namely, the cutting part of the drilling tool is made of hard alloy, the clamping part is made of low-hardness steel materials, and the cutting part can be independently replaced after the cutting part is worn, so that the cost performance of the drilling tool is high, and the split type drilling tool is widely applied.

However, in the drilling process of the drilling tool with the clamping part made of steel materials, as the cutting part of the tool completely penetrates into the workpiece and forms a closed area with the workpiece, chips are difficult to curl and difficult to discharge, in order to ensure the cutting performance of the drilling tool, the drilling tool is generally provided with large-area chip flutes, in the prior art, the chip removal capacity is generally improved by adopting a spiral concave with a U-shaped circular arc bottom as the chip flute, the structure is simple and the manufacturing is convenient, but in order to ensure the chip removal capacity of the chip flutes, the core thickness between the tool body and the chip flutes is small, the rigidity of the tool body is seriously reduced, the drilling depth of the tool body is small, and the drilling efficiency is low.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects of the prior art and providing the drilling tool which has good rigidity, large drilling depth and smooth chip removal.

In order to solve the technical problems, the invention adopts the following technical scheme:

the utility model provides a drilling tool, includes cutter body and cutting blade, the cutter body includes centre gripping stalk portion, cutting tip and is located the cutter body global between centre gripping stalk portion, the cutting tip, centre gripping stalk portion, cutter body global all are with the rotation center axis symmetry of cutting cutter body, the chip pocket has been seted up on the cutter body global, be equipped with on the cutting tip with the communicating sword groove of chip pocket, the fixed installation of cutting blade is in the sword inslot, the chip pocket includes the concave surface, the bottom surface of concave surface outwards is arch structure.

As a further improvement of the above technical scheme:

the cutting blade comprises a core cutting blade positioned on a rotation central shaft, the concave surface of the chip pocket corresponding to the core cutting blade is a core concave surface, the core concave surface comprises an upper core straight-rotation surface, a lower core straight-rotation surface and a core concave bottom surface, and the core concave bottom surface is arranged between the upper core straight-rotation surface and the lower core straight-rotation surface.

The core concave bottom surface comprises two core bottom straight side surfaces and a core bottom straight top surface positioned between the two core bottom straight side surfaces, and in a plane orthogonal to the rotation center axis and intersecting the core concave surface, an included angle of the two core bottom straight side surfaces is alpha, and the two core bottom straight side surfaces are required to satisfy: alpha is more than or equal to 120 degrees and less than or equal to 160 degrees.

The diameter of the drilling tool is D, and the width of the straight top surface of the core bottom is W in a plane orthogonal to the rotation central axis and intersecting with the core concave surface, so that the width of the straight top surface of the core bottom is as follows: w is more than or equal to 0.1D and less than or equal to 0.2D.

The minimum distance between the center of the straight top surface of the core bottom and the peripheral surface of the cutter body is L, and the minimum distance should satisfy: l is more than or equal to 0.05D and less than or equal to 0.1D.

The middle part of the straight top surface of the core bottom is provided with a concave core arc surface, the radius of the concave core arc surface is R, and the following requirements are met: r is more than or equal to 0.07D and less than or equal to 0.15D.

In a plane orthogonal to the rotation central axis and intersecting with the core concave surface, an included angle between the upper straight rotation surface and the lower straight rotation surface of the core is beta, and the following conditions are satisfied: beta is more than or equal to 10 degrees and less than or equal to 40 degrees.

A core angle arc surface is arranged between the straight side surface of the core bottom and the corresponding straight rotating surface on the core or the corresponding straight rotating surface under the core, and in a plane orthogonal to the rotation center shaft and intersecting with the core concave surface, the tangential distance between the core angle arc surface and the straight top surface of the core bottom is H, so that the following conditions are satisfied: h is more than or equal to 0.02D and less than or equal to 0.1D.

Passivation surfaces are arranged between the upper straight rotation surface of the core, the lower straight rotation surface of the core and the peripheral surface of the cutter body.

The cutting blade comprises a core cutting blade positioned on a rotating central shaft and a peripheral cutting blade positioned on the peripheral surface of the blade body, wherein the concave surface of the chip pocket corresponding to the core cutting blade is a core concave surface, the core concave surface comprises an upper core straight-rotating surface, a lower core straight-rotating surface and a core concave bottom surface, the core concave bottom surface is arranged between the upper core straight-rotating surface and the lower core straight-rotating surface, the concave surface of the chip pocket corresponding to the peripheral cutting blade is a peripheral concave surface, the peripheral concave surface comprises a peripheral upper straight-rotating surface, a peripheral lower straight-rotating surface and a peripheral concave bottom surface, and the peripheral concave bottom surface is arranged between the peripheral upper straight-rotating surface and the peripheral lower straight-rotating surface.

The peripheral concave bottom surface comprises two peripheral straight side surfaces and a Zhou Zhi top surface positioned between the two peripheral straight side surfaces, and the included angle of the two peripheral straight side surfaces is alpha' in a plane orthogonal to the rotation center axis and intersecting with the peripheral concave surface, so that the following conditions are satisfied: alpha is less than or equal to 100 degrees and alpha is less than or equal to 140 degrees.

The diameter of the drilling tool is D, and the width of the Zhou Zhi top surface is W' in a plane orthogonal to the rotation central axis and intersecting with the peripheral concave surface, so that the following conditions are satisfied: w' is more than or equal to 0.01D and less than or equal to 0.15D.

The minimum distance between the center of the top surface of Zhou Zhi and the peripheral surface of the cutter body is L', and the minimum distance should be satisfied: l' is more than or equal to 0.1D and less than or equal to 0.2D.

The circumference concave arc surface is arranged in the middle of the circumference concave bottom surface, and the Zhou Aoyuan arc surface is R', and the following requirements are satisfied: r' is more than or equal to 0.07D and less than or equal to 0.15D.

In the plane orthogonal to the rotation center axis and intersecting the core recessed surface, the included angle between the upper straight-rotation surface and the lower straight-rotation surface of the core is beta, and in the plane orthogonal to the rotation center axis and intersecting the peripheral recessed surface, the included angle between the upper straight-rotation surface and the lower straight-rotation surface is beta', which is satisfied: beta is more than or equal to 10 degrees and less than or equal to 40 degrees, and beta' -beta is more than or equal to 10 degrees and less than or equal to 40 degrees.

A core angle arc surface is arranged between the straight side surface of the core bottom and the corresponding straight rotating surface on the core or the straight rotating surface under the core, the tangential distance between the core angle arc surface and the straight side surface of the core top is H in a plane orthogonal to the rotation center shaft and intersecting with the core concave surface, a circumference angle arc surface is arranged between the Zhou Zhi side surface and the corresponding straight rotating surface on the circumference or the straight rotating surface under the circumference, and the tangential distance between the circumference angle arc surface and the Zhou Zhi top surface is H' in a plane orthogonal to the rotation center shaft and intersecting with the circumference concave surface, so that the following conditions are satisfied: h is more than or equal to 0.02D and less than or equal to 0.1D, H' -H is more than or equal to 0.02D and less than or equal to 0.1D.

Compared with the prior art, the invention has the advantages that:

the drilling tool comprises a tool body and a cutting blade, wherein the tool body comprises a clamping handle part, a cutting end part and a tool body peripheral surface positioned between the clamping handle part and the cutting end part, the clamping handle part and the tool body peripheral surface are symmetrical relative to a rotation center axis of the cutting tool body, chip pockets are formed in the tool body peripheral surface, the cutting end part is provided with the tool pockets communicated with the chip pockets, the cutting blade is fixedly arranged in the tool pockets, the chip pockets comprise concave surfaces, the bottoms of the concave surfaces are of an outwards arch structure, the rigidity of the drilling tool can be greatly improved, and therefore, the drilling dimensional accuracy, the drilling surface quality and the maximum allowable drilling depth of the drilling tool can be improved, the cutting tool can still stably cut even if the diameter of the drilling tool is suspended by more than 7 times, the chip discharging capacity of the chip pockets is not completely dependent on the chip pocket structure with the size of the concave sectional area, and the chip discharging capacity of the drilling tool can be greatly improved.

Drawings

Fig. 1 is a perspective view of a first embodiment of a drilling tool according to the present invention.

Fig. 2 is a front view of a first embodiment of the drilling tool of the present invention.

Fig. 3 is A-A view of fig. 2.

Fig. 4 is a perspective view showing a second embodiment of the drilling tool of the present invention.

Fig. 5 is a front view of a second embodiment of the drilling tool of the present invention.

Fig. 6 is a B-B view of fig. 5.

The reference numerals in the drawings denote:

1. a cutter body; 2. a cutting insert; 21. a core cutting insert; 22. a peripheral cutting blade; 3. cutting the end; 4. clamping the handle; 5. a knife slot; 6. a cutter body peripheral surface; 7. chip-containing grooves; 8. a recessed surface; 81. a core recessed surface; 811. a straight rotation surface on the core; 812. a lower straight rotation surface of the core; 813. the core is recessed into the bottom surface; 8131. straight side of core bottom; 8132. a straight top surface of the core bottom; 814. a concave core arc surface; 815. a core angle arc surface; 82. a peripheral recessed surface; 821. a peripheral straight rotation surface; 822. a lower peripheral straight rotation surface; 823. a peripheral recessed bottom surface; 8231. zhou Zhi side; 8232. zhou Zhi top surface; 824. zhou Aoyuan cambered surfaces; 825. circumferential arc surfaces; 9. a passivation surface; 10. a fastener; 11. and rotating the central shaft.

Detailed Description

The invention will be described in further detail with reference to the drawings and the specific examples.

Fig. 1 to 3 show a first embodiment of a split drilling tool according to the present invention, the drilling tool of the embodiment comprises a tool body 1 and a cutting insert 2, the tool body 1 comprises a clamping shank 4, a cutting end 3 and a tool body peripheral surface 6 positioned between the clamping shank 4 and the cutting end 3, the clamping shank 4 and the tool body peripheral surface 6 are symmetrical about a rotation center axis 11 of the cutting tool body 2, chip flutes 7 are formed on the tool body peripheral surface 6, the cutting end 3 is provided with the tool flutes 5 communicated with the chip flutes 7, the cutting insert 2 is fixedly arranged in the tool flutes 5, the chip flutes 7 comprise a concave surface 8, the bottom surface of the concave surface 8 is in an outwards arched structure, the specific shape chips formed by the cutting insert 2 do not form large-area extrusion with the bottom surface of the concave surface 8, the chip removal smoothness is improved, the rigidity of the drilling tool can be greatly improved, the drilling surface quality and the maximum allowable drilling depth are improved, the cutting tool can still can discharge chip flutes more than 7 times the diameter, and the chip cutting capacity can be greatly improved.

In this embodiment, the cutting insert 2 includes a core cutting insert 21 located on the rotation center axis 11, the recess surface 8 of the chip pocket 7 corresponding to the core cutting insert 21 is a core recess surface 81, the core recess surface 81 includes a core upper straight rotation surface 811, a core lower straight rotation surface 812, and a core recess bottom surface 813, and the core recess bottom surface 813 is provided between the core upper straight rotation surface 811 and the core lower straight rotation surface 812.

In this embodiment, the core concave bottom surface 813 includes two straight core bottom side surfaces 8131 and a straight core bottom top surface 8132 located between the two straight core bottom side surfaces 8131, in order to avoid chip contact between the straight core top surface 811 or the straight core bottom surface 812 and the straight core bottom side surfaces 8131, and improve chip removal effect of the core concave surface 81, in a plane orthogonal to the rotation center axis 11 and intersecting the core concave surface 81, an included angle α between the two straight core bottom side surfaces 8131 should be satisfied: 120 ° or more and α or less than 160 °, in this embodiment, α=140°.

In this embodiment, the diameter of the drilling tool is D, and the width of the core bottom straight top surface 8132 is W in a plane orthogonal to the rotation center axis 11 and intersecting the core recessed surface 81, so as to control the chip contact area between the core upper straight surface 811 or the core lower straight surface 812 and the core bottom straight top surface 8231, the following is satisfied: w is 0.1 d.ltoreq.w.ltoreq.0.2D, w=0.15D in this example.

In this embodiment, the minimum distance between the center of the straight top surface 8132 of the core bottom and the peripheral surface 6 of the cutter body is L, and in order to ensure the discharge capability of the chips of a specific shape in the core recessed surface 81, it should be satisfied that: l is 0.05 d.ltoreq.0.1D, in this example l=0.15D.

In this embodiment, a concave core arc surface 814 is disposed in the middle of the straight top surface 8132 of the core bottom, where the radius of the concave core arc surface 814 is R, to accurately control the flow direction of the chips in the straight top surface 8132 of the core bottom, it should satisfy: r is 0.07 d.ltoreq.r.ltoreq.0.15D, in this example r=0.1D.

In this embodiment, in the plane orthogonal to the rotation center axis 11 and intersecting the core recessed surface 81, the angle between the upper core straight-turning surface 811 and the lower core straight-turning surface 812 is β, and in order to secure the bending rigidity of the cutter body 1 and to improve the chip discharging capability of a specific shape in the core recessed surface 81, it is desirable that: beta is 10 deg. or more and 40 deg., in this example beta=20 deg..

In this embodiment, a core angle arc surface 815 is disposed between the straight side surface 8131 of the core bottom and the corresponding straight side surface 811 of the core upper or straight side surface 812 of the core lower, and in a plane orthogonal to the rotation central axis 11 and intersecting with the core concave surface 81, the tangential distance between the core angle arc surface 815 and the straight top surface 8132 of the core bottom is H, so as to optimize the stress distribution condition at the intersection of the straight side surface 811 of the core upper, straight side surface 812 of the core lower and straight side surface 8131 of the core bottom, avoid fatigue fracture of the cutter body 1, and should satisfy the following requirements: h is 0.02 d.ltoreq.h.ltoreq.0.1D, in this example h=0.25D.

In this embodiment, passivation surfaces 9 are disposed between the upper core straight-turning surface 811, the lower core straight-turning surface 812 and the cutter body peripheral surface 6, so as to avoid the cutter body peripheral surface 6 from being broken.

Fig. 4 to 6 show a second embodiment of the split drilling tool according to the invention, which differs from the first embodiment in that: the cutting insert 2 includes a core cutting insert 21 located on the rotation center shaft 11 and a peripheral cutting insert 22 located on the insert body peripheral surface 6, the recessed surface 8 of the chip pocket 7 corresponding to the core cutting insert 21 being a core recessed surface 81, the core recessed surface 81 including a core upper straight-rotation surface 811, a core lower straight-rotation surface 812, and a core recessed bottom surface 813, the core recessed bottom surface 813 being provided between the core upper straight-rotation surface 811 and the core lower straight-rotation surface 812, the recessed surface 8 of the chip pocket 7 corresponding to the peripheral cutting insert 22 being a peripheral recessed surface 82, the peripheral recessed surface 82 including a peripheral upper straight-rotation surface 821, a peripheral lower straight-rotation surface 822, and a peripheral recessed bottom surface 823, the peripheral recessed bottom surface 823 being provided between the peripheral upper straight-rotation surface 821 and the peripheral lower straight-rotation surface 822.

In this embodiment, the peripheral concave bottom surface 823 includes two peripheral straight side surfaces 8231 and a top surface 8232 of Zhou Zhi located between the two peripheral straight side surfaces 8231, and in a plane orthogonal to the rotation center axis 11 and intersecting the peripheral concave surface 82, an included angle of the two peripheral straight side surfaces 8231 is α', so as to avoid chip contact between the peripheral upper straight surface 821 and the peripheral lower straight surfaces 822 and Zhou Zhice surfaces 8231, and improve chip removal effect of the peripheral concave surface 82, which should be satisfied: alpha 'is less than or equal to 100 deg. and less than or equal to 140 deg., in this example, alpha' =120 deg..

In this embodiment, the diameter of the drilling tool is D, and the width of the top surface 8232 of Zhou Zhi is W' in a plane orthogonal to the rotation center axis 11 and intersecting the peripheral recess surface 82, so as to control the chip contact area between the peripheral upper and lower straight surfaces 821, 822 and Zhou Zhice, 8231, and satisfy the following conditions: 0.01 d.ltoreq.w '.ltoreq.0.15D, W' =0.12D in this example.

In this embodiment, the minimum distance between the center of the top surface 8232 of Zhou Zhi and the peripheral surface 6 of the cutter body is L', and in order to ensure the discharge capability of the chips of a specific shape in the peripheral concave surface 82, it should be satisfied that: l' is more than or equal to 0.1D and less than or equal to 0.2D.

In this embodiment, a circumferential arc surface 824, zhou Aoyuan arc surface 824 is provided in the middle of the circumferential concave bottom surface 823, and the following should be satisfied: r' is more than or equal to 0.07D and less than or equal to 0.15D.

In the present embodiment, in the plane orthogonal to the rotation center axis 11 and intersecting the core concave surface 81, the angle between the upper core straight surface 811 and the lower core straight surface 812 is β, and in the plane orthogonal to the rotation center axis 11 and intersecting the peripheral concave surface 82, the angle between the upper peripheral straight surface 821 and the lower peripheral straight surface 822 is β', in order to secure the bending rigidity of the cutter body 1 and to improve the chip discharging capability of the specific shape in the core concave surface 81 and the peripheral concave surface 82, it is desirable that: beta is more than or equal to 10 degrees and less than or equal to 40 degrees, beta '-beta is more than or equal to 10 degrees and less than or equal to 40 degrees, and beta=20 degrees and beta' =60 degrees in the embodiment.

In this embodiment, a core angular arc surface 815 is disposed between the core bottom straight side surface 8131 and the corresponding core upper straight side surface 811 or core lower straight side surface 812, the tangential distance between the core angular arc surface 815 and the core top straight side surface 8132 is H in a plane orthogonal to the rotation central axis 11 and intersecting the core recessed surface 81, a circumferential arc surface 825 is disposed between the Zhou Zhice surface 8231 and the corresponding circumferential straight side surface 821 or circumferential lower straight side surface 822, and the tangential distance between the circumferential arc surface 825 and the Zhou Zhi top surface 8232 is H' in a plane orthogonal to the rotation central axis 11 and intersecting the circumferential recessed surface 82, so as to optimize the stress distribution conditions at the intersections of the core upper straight side surface 811, the core lower straight side surface 812 and the core bottom straight side surface 8131 and at the intersections of the circumferential straight side surface 821, the circumferential lower straight side surface 822 and the circumferential bottom straight side surface 8231, and avoid fatigue fracture of the cutter body 1, which should be satisfied: h is 0.02 d.ltoreq.h.ltoreq.0.1D, H '-H is 0.02 d.ltoreq.h.ltoreq.0.1D, in this example h=0.25D, H' =0.3D.

While the invention has been described in terms of preferred embodiments, it is not intended to be limiting. Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art, or equivalent embodiments with equivalent variations can be made, without departing from the scope of the invention. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. The utility model provides a drilling tool, includes cutter body (1) and cutting blade (2), cutter body (1) include centre gripping stalk portion (4), cutting tip (3) and be located cutter body global (6) between centre gripping stalk portion (4), cutting tip (3), centre gripping stalk portion (4), cutter body global (6) are all with respect rotation center pin (11) symmetry of cutting blade (2), chip pocket (7) have been seted up on cutter body global (6), be equipped with on cutting tip (3) with chip pocket (7) communicating sword groove (5), cutting blade (2) are fixed to be installed in sword groove (5), its characterized in that: the chip flute (7) comprises a concave surface (8), the bottom surface of the concave surface (8) is in an outwards arched structure, the cutting blade (2) comprises a core cutting blade (21) positioned on a rotation center shaft (11), the concave surface (8) of the chip flute (7) corresponding to the core cutting blade (21) is a core concave surface (81), the core concave surface (81) comprises a core upper straight surface (811), a core lower straight surface (812) and a core concave bottom surface (813), the core concave bottom surface (813) is arranged between the core upper straight surface (811) and the core lower straight surface (812), the core concave bottom surface (813) comprises two core bottom straight side surfaces (8131) and a core bottom straight top surface (8132) positioned between the two core bottom straight side surfaces (8131), and the included angle alpha between the two core bottom straight side surfaces (8131) is satisfied in a plane which is orthogonal to the rotation center shaft (11) and intersects the core concave surface (81): alpha is more than or equal to 120 degrees and less than or equal to 160 degrees.

2. The drilling tool as recited in claim 1, wherein: the diameter of the drilling tool is D, and the width of the straight top surface (8132) of the core bottom is W in a plane which is orthogonal to the rotation central shaft (11) and is intersected with the core concave surface (81), so that the width is as follows: w is more than or equal to 0.1D and less than or equal to 0.2D.

3. The drilling tool as recited in claim 1, wherein: the minimum distance between the center of the straight top surface (8132) of the core bottom and the peripheral surface (6) of the cutter body is L, and the minimum distance should satisfy: l is more than or equal to 0.05D and less than or equal to 0.1D.

4. The drilling tool as recited in claim 1, wherein: the middle part of the straight top surface (8132) of the core bottom is provided with a concave core arc surface (814), the radius of the concave core arc surface (814) is R, and the requirements are satisfied: r is more than or equal to 0.07D and less than or equal to 0.15D.

5. The drilling tool as recited in claim 1, wherein: in a plane orthogonal to the rotation center axis (11) and intersecting the core recessed surface (81), an included angle between the upper core straight rotation surface (811) and the lower core straight rotation surface (812) is beta, and the following conditions are satisfied: beta is more than or equal to 10 degrees and less than or equal to 40 degrees.

6. The drilling tool as recited in claim 1, wherein: a core angle arc surface (815) is arranged between the straight side surface (8131) of the core bottom and the corresponding straight rotating surface (811) or straight rotating surface (812) of the core bottom, and in a plane orthogonal to the rotation center shaft (11) and intersecting with the core concave surface (81), the tangential distance between the core angle arc surface (815) and the straight top surface (8132) of the core bottom is H, and the following conditions are satisfied: h is more than or equal to 0.02D and less than or equal to 0.1D.

7. Drilling tool according to any one of claims 2-6, characterized in that: passivation surfaces (9) are arranged between the upper straight rotation surface (811) of the core, the lower straight rotation surface (812) of the core and the peripheral surface (6) of the cutter body.

8. The drilling tool as recited in claim 1, wherein: the cutting insert (2) further comprises a peripheral cutting insert (22) located on the peripheral surface (6) of the insert body, a concave surface (8) of a chip pocket (7) corresponding to the peripheral cutting insert (22) is a peripheral concave surface (82), the peripheral concave surface (82) comprises a peripheral upper straight-rotation surface (821), a peripheral lower straight-rotation surface (822) and a peripheral concave bottom surface (823), and the peripheral concave bottom surface (823) is arranged between the peripheral upper straight-rotation surface (821) and the peripheral lower straight-rotation surface (822).

9. The drilling tool as recited in claim 8, wherein: the peripheral concave bottom surface (823) comprises two peripheral straight side surfaces (8231) and a Zhou Zhi top surface (8232) positioned between the two peripheral straight side surfaces (8231), and an included angle alpha' of the two peripheral straight side surfaces (8231) in a plane orthogonal to the rotation center shaft (11) and intersecting the peripheral concave surface (82) is satisfied: alpha is less than or equal to 100 degrees and alpha is less than or equal to 140 degrees.

10. The drilling tool as recited in claim 9, wherein: the diameter of the drilling tool is D, and the width of the top surface (8232) of the Zhou Zhi is W' in a plane which is orthogonal to the rotation central shaft (11) and is intersected with the peripheral concave surface (82), so that the width is as follows: w' is more than or equal to 0.01D and less than or equal to 0.15D.

11. The drilling tool as recited in claim 9, wherein: the minimum distance between the center of the top surface (8232) of the Zhou Zhi and the peripheral surface (6) of the cutter body is L', and the minimum distance is as follows: l' is more than or equal to 0.1D and less than or equal to 0.2D.

12. The drilling tool as recited in claim 9, wherein: the middle of the circumference concave bottom surface (823) is provided with a circumference concave arc surface (824), and the Zhou Aoyuan arc surface (824) is R', so that the following conditions are satisfied: r' is more than or equal to 0.07D and less than or equal to 0.15D.

13. The drilling tool as recited in claim 9, wherein: in a plane orthogonal to the rotation center axis (11) and intersecting the core recessed surface (81), an included angle between the upper core straight-rotation surface (811) and the lower core straight-rotation surface (812) is beta, and in a plane orthogonal to the rotation center axis (11) and intersecting the peripheral recessed surface (82), an included angle between the upper peripheral straight-rotation surface (821) and the lower peripheral straight-rotation surface (822) is beta', which is satisfied: beta is more than or equal to 10 degrees and less than or equal to 40 degrees, and beta' -beta is more than or equal to 10 degrees and less than or equal to 40 degrees.

14. The drilling tool as recited in claim 9, wherein: a core angle arc surface (815) is arranged between the straight side surface (8131) of the core bottom and the corresponding straight rotating surface (811) or straight rotating surface (812) of the core bottom, in a plane orthogonal to the rotation center shaft (11) and intersecting with the core concave surface (81), the tangential distance between the core angle arc surface (815) and the straight top surface (8132) of the core bottom is H, a circumference angle arc surface (825) is arranged between the side surface (8231) of the Zhou Zhi and the corresponding straight rotating surface (821) or straight rotating surface (822) of the core bottom, and in a plane orthogonal to the rotation center shaft (11) and intersecting with the circumference concave surface (82), the tangential distance between the circumference angle arc surface (825) and the top surface (8232) of the Zhou Zhi is H', which is satisfied: h is more than or equal to 0.02D and less than or equal to 0.1D, H' -H is more than or equal to 0.02D and less than or equal to 0.1D.