CN111872450A

CN111872450A - Cutter for machining taper hole

Info

Publication number: CN111872450A
Application number: CN202010772105.4A
Authority: CN
Inventors: 贾志翔; 熊国源; 杨小禹; 邓天翼; 陈志�; 范鑫; 刘海龙; 范思洋; 方正强; 朱文涛; 田烨玲
Original assignee: Citic Dicastal Co Ltd
Current assignee: Citic Dicastal Co Ltd
Priority date: 2020-08-04
Filing date: 2020-08-04
Publication date: 2020-11-03

Abstract

The invention belongs to the technical field of machining cutter manufacturing, and provides a cutter for machining a taper hole, which comprises a cutter handle, a taper hole cutting part and a drill bit which are sequentially connected, wherein the drill bit can be used for pre-drilling, chip removal grooves of the taper hole cutting part are mutually staggered and alternately arranged, so that a chip removal space is large, chips are timely and smoothly removed, the metal removal rate is high, the machining efficiency is increased, each cutting edge of the cutter is not influenced in the machining process, and simultaneously the cutting resistance is dispersed, so that the cutter shaking phenomenon caused by resonance is avoided; the cutting edges are in a step shape which rises towards the direction of the tool handle, so that the tool vibration phenomenon in the machining process is avoided by dispersing cutting resistance, the machining heat can be dispersed, the phenomenon that the cutting heat is gathered to a sharp point is avoided, and the service life of the tool is prolonged.

Description

Cutter for machining taper hole

Technical Field

The application relates to the technical field of machining cutter manufacturing, in particular to a cutter for machining a taper hole.

Background

With the development of automobile lightweight technology, more and more aluminum alloy parts are applied to automobiles. An automobile steering knuckle is also one of important parts in a steering system, and a plurality of manufacturers adopt aluminum alloy materials to manufacture the steering knuckle so as to reduce the self weight of a vehicle body. The automobile steering knuckle parts are designed to be provided with taper hole structures due to the requirements of structures and fatigue life, and the processing difficulty of the taper holes is much higher than that of straight holes. The cutter is easy to shake when the allowance is removed in the rough machining of the taper hole, the resistance is large, and the machining efficiency is low. In particular, the processing of large taper holes and deep taper holes is more difficult.

Disclosure of Invention

The embodiment of the application provides a cutter for processing taper hole, can improve the machining efficiency of taper hole rough machining greatly, avoids shaking the sword, and the ordinary cutter of taper hole finish machining of deuterogamying then can high-efficiently accomplish the processing of taper hole.

In order to achieve the purpose, the invention provides the following technical scheme:

the embodiment of the application provides a cutter for machining a taper hole, which comprises a cutter handle, a taper hole cutting part and a drill bit, wherein the cutter handle, the taper hole cutting part and the drill bit are sequentially connected, the taper hole cutting part comprises at least one first front chip groove close to the drill bit, at least one first rear chip groove close to the cutter handle, a first cutting edge and a second cutting edge, and the first front chip groove and the first rear chip groove are staggered and alternately arranged; each first front chip groove is provided with the first cutting edge, and each first rear chip groove is provided with the second cutting edge; the circumferential cutting tracks of the first cutting edges are the same, and the circumferential cutting tracks of the second cutting edges are the same; the first cutting edge and the second cutting edge are both in a step shape which rises towards the direction of the tool shank, and the circumferential cutting tracks of the first cutting edge and the second cutting edge are continuous. The special cutter structure design is provided for the characteristics of taper hole machining in the embodiment, the special cutter structure design comprises a cutter handle, a taper hole cutting part and a drill bit which are sequentially connected, the drill bit can be used for pre-drilling, the first front chip removal grooves and the first rear chip removal grooves of the taper hole cutting part are staggered and alternately arranged, so that the machining process of each cutting edge of the cutter is not influenced mutually, the phenomenon of cutter vibration caused by resonance is avoided, the cutting resistance is dispersed, the cutter vibration phenomenon is avoided, the first cutting edge and the second cutting edge are in a stepped shape which rises towards the direction of the cutter handle, the cutter vibration phenomenon in the machining process is avoided by dispersing the cutting resistance, the machining heat can be dispersed, the phenomenon that the cutting machining heat is gathered at a sharp point is avoided, and the service life of the cutter is; the chip removal grooves are staggered and arranged alternately, the chip removal space is large, chips are removed timely and smoothly, the chip removal of the taper hole cutting part and the chip removal of the drill bit cutting part are not influenced mutually, the metal removal rate is high, the machining efficiency is increased, and the machining cost of an enterprise is reduced.

In some embodiments, the drill comprises a drill tip and a drill body, the drill tip is positioned at the tip end of the drill body, and drill chip removing grooves are formed on two sides of the drill tip; the drill bit flutes each extend from the tip to the base of the shank. The drill bit has lengthened chip groove length in this embodiment, follows the most advanced of boring body extends to the bottom to mutual noninterference with the chip removal during taper hole cutting process when making the drill bit predrill.

In some embodiments, the junction of the shank and the countersink cutting portion is configured as a curved surface. In the embodiment, the cutter handle and the cutting part of the taper hole are in transition connection by adopting the radius curve, so that the cutter is prevented from generating stress concentration possibly, the rigidity of the cutter body is enhanced, and the possibility of generating cutter vibration is greatly reduced.

In some embodiments, the tool for machining a taper hole is provided with a main coolant channel along an axial core portion thereof, and the first front chip groove and the first rear chip groove are both provided therein with internal cooling holes communicated with the main coolant channel. In some embodiments, the tool for machining a taper hole is provided with a main coolant channel along an axial core portion thereof, and the first front chip groove and the first rear chip groove and both sides of the drill tip are provided with internal cooling holes communicated with the main coolant channel. In the above embodiment, the inner cooling hole is aligned with the cutting edge or the drill tip, and the cooling liquid can not only wash away chips, but also take away cutting heat, thereby reducing the processing temperature of the cutter and prolonging the service life of the cutter.

In some embodiments, the sum of the cross-sectional areas of all of the internal cooling holes is no greater than the cross-sectional area of the main coolant passage, so as to ensure sufficient pressure of the coolant in the main coolant passage.

In some embodiments, a first insert pocket is provided on an edge of the first front flute, the first cutting edge being secured within the first insert pocket; a second blade groove is formed in the edge of the first rear chip groove, and the second cutting edge is fixed in the second blade groove; the first blade groove and the second blade groove are both open circular arc-shaped. In this embodiment, the blade groove is designed to be an open arc, which improves the welding strength of the blade and increases the chip removal space of chips.

On the other hand, another embodiment of the present application provides a tool for machining a taper hole, including a tool holder, a taper hole cutting portion and a drill bit, which are connected in sequence, wherein the taper hole cutting portion includes at least one cutting section, each cutting section includes at least one chip removal groove uniformly arranged along a circumference, and all the chip removal grooves of all the cutting sections are arranged in a mutually staggered and alternating manner on the whole; a cutting edge is fixed on each chip groove, and the circumferential cutting tracks of the cutting edges of each cutting section are the same; each cutting edge is in a step shape which rises towards the direction of the cutter handle, and the circumferential cutting tracks of the cutting edges of the cutting sections are connected. In the embodiment, a special tool structural design is provided for the characteristics of taper hole processing, the special tool structural design comprises a tool handle, a taper hole cutting part and a drill bit which are sequentially connected, the drill bit can be used for pre-drilling, all chip grooves of all cutting sections are integrally arranged in a staggered and alternate mode, so that the processing process of each cutting edge of the tool is not influenced mutually, the phenomenon of tool vibration caused by resonance is avoided, the cutting resistance is dispersed, the phenomenon of tool vibration is avoided, each cutting edge is in a step shape which rises towards the tool handle, the cutting resistance is dispersed, the phenomenon of tool vibration in the processing process is avoided, the processing heat can be dispersed, the phenomenon of sharp point accumulation of the cutting heat is avoided, and the service life of the tool is prolonged; the chip removal grooves are staggered and arranged alternately, the chip removal space is large, chips are removed timely and smoothly, the chip removal of the taper hole cutting part and the chip removal of the drill bit cutting part are not influenced mutually, the metal removal rate is high, the machining efficiency is increased, and the machining cost of an enterprise is reduced.

In some embodiments, the tool for machining the taper hole is provided with a main coolant channel along an axial core portion, and each chip groove is internally provided with an internal cooling hole communicated with the main coolant channel. In some embodiments, the tool for machining the taper hole is provided with a main coolant channel along an axial core portion thereof, and each flute and two sides of the drill tip of the taper hole cutting portion are provided with internal cooling holes communicated with the main coolant channel. In the above embodiment, the inner cooling hole is aligned with the cutting edge or the drill tip, and the cooling liquid can not only wash away chips, but also take away cutting heat, thereby reducing the processing temperature of the cutter and prolonging the service life of the cutter.

In some embodiments, an insert pocket is provided on an edge of the flute, and the cutting edge is fixed in the insert pocket; the blade groove is of an open arc shape. In this embodiment, the blade groove is designed to be an open arc, which improves the welding strength of the blade and increases the chip removal space of chips.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a cutter for processing a taper hole, which provides a special cutter structure design aiming at the characteristics of taper hole processing, and comprises a cutter handle, a taper hole cutting part and a drill bit which are sequentially connected, wherein the drill bit can be used for pre-drilling, and chip grooves of the taper hole cutting part are staggered and alternately arranged, so that the processing process of each cutting edge of the cutter is not influenced mutually, the phenomenon of cutter vibration caused by resonance is avoided, the cutting resistance is dispersed, the cutter vibration phenomenon is avoided, the cutting edges are in a step shape which rises towards the direction of the cutter handle, the cutter vibration phenomenon in the processing process is avoided by dispersing the cutting resistance, the processing heat can be dispersed, the phenomenon that the cutting heat is concentrated at a sharp point is avoided, and the service life of the cutter is prolonged; the chip removal grooves are staggered and arranged alternately, the chip removal space is large, chips are removed timely and smoothly, the chip removal of the taper hole cutting part and the chip removal of the drill bit cutting part are not influenced mutually, the metal removal rate is high, the machining efficiency is increased, and the machining cost of an enterprise is reduced. The cutter has the advantages of compact structure, large chip removal space and good rigidity, all chip removal grooves are staggered alternately, the chip resistance is dispersed, the phenomenon of cutter vibration in machining caused by resonance is eliminated, and the allowance removal machining efficiency is improved; the step shape of the cutting edge is beneficial to heat dissipation, the service life of the cutter is prolonged, meanwhile, the requirement of processing takt is met, and the processing cost of a production enterprise is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic perspective view of a tool for machining a tapered hole according to the present application.

Fig. 2 is a front view of a tool for machining a taper hole according to the present application.

Fig. 3 is a schematic top view of a tool for machining a tapered hole according to the present application.

Fig. 4 is a drill point direction end view of a tool for machining a tapered hole of the present application.

Wherein: 1-tool shank, 2-taper hole cutting part, 3-drill, 301-drill tip, 302-first internal cooling hole of drill, 303-second internal cooling hole of drill, 304-drill chip groove, 305-drill body, 4-arc curved surface, 5-main cooling liquid channel, 6-first front chip groove, 7-first rear chip groove, 8-first cutting edge, 9-second cutting edge, 10-first blade groove, 11-second blade groove and 12-taper hole cutting part internal cooling hole.

Detailed Description

The terms "first," "second," "third," and "fourth," etc. in the description and claims of this application and in the accompanying drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Example 1:

in embodiment 1, there is provided a tool for roughing a taper hole, as shown in fig. 1, including a tool shank 1, a taper hole cutting portion 2, and a drill 3 connected in this order, and a tool body is made of high-speed tool steel. The tool shank form of the product can be flexibly designed into HSK tool shank types, BT tool shank types, SK tool shanks, BBT tool shanks and the like according to the machine tool interface types. The embodiment is described by taking the HSK-A63 knife handle type as an example.

It is seen from fig. 2 that the tool holder 1 is composed of a hollow conical curved surface at a clamping end and a tool changing clamping groove, the tool holder 1 is transitionally connected with the taper hole cutting part 2 by adopting a radius curve, as shown in fig. 2-3, and the tool holder 1 is connected with the taper hole cutting part 2 through an arc curved surface 4. The design of the arc curved surface 4 enhances the rigidity of cutter processing, avoids stress concentration, improves the processing stability of workpieces, and greatly reduces the possibility of cutter vibration.

The drill bit 3 comprises a drill tip 301 and a drill body 305, wherein the drill tip 301 is located at the tip end of the drill body 305, drill chip flutes 304 are formed on two sides of the drill tip 301, and the drill chip flutes 304 extend from the tip end to the bottom end of the drill body 305. With reference to fig. 2, 3 and 4, it can be seen that the drill bit 3 mainly comprises a PCD drill tip 301 or a detachable cemented carbide replaceable drill tip 301, a first inner cold hole 302 of the drill bit, a second inner cold hole 303 of the drill bit, a drill chip groove 304 and a drill body 305. Drill point 301 both sides are opened respectively and are had elongated drill bit chip groove 304, drill bit chip groove 304 all follows the most advanced of boring body 305 extends to the bottom, and drill bit 3 guarantees that the taper hole cutting part does not participate in processing when carrying out the processing of predrilling, and its core thickness of both chips removal mutual noninterference simultaneously sets for and satisfies the processing rigidity demand. The drill tip 301 can be a PCD drill tip or a hard alloy replaceable drill tip according to the material and the processing technology of a processing workpiece, the service life of the PCD drill tip is long, and the drill tip replacement of the hard alloy replaceable drill tip is convenient. The cutter body is provided with a main cooling liquid channel 5 along the axial core part, the aperture of the main cooling liquid channel is determined by the outer diameter of the cutter handle and the cutting part of the taper hole, and the requirements of cooling liquid pressure and machining rigidity of the cutter are met. Interior cold hole has all been seted up behind drill point 301 (the both sides of drill point promptly), cold hole 303 all with in the first interior cold hole 302 of drill bit and the second of drill bit 5 intercommunications, both can play the refrigerated effect and also can play the effect of supplementary chip removal.

The taper hole cutting part 2 comprises two cutting sections, each cutting section comprises two chip grooves which are uniformly arranged along the circumference, as shown in fig. 2-4, the first cutting section comprises two first front chip grooves 6 which are close to the drill bit 1, the second cutting section comprises two first rear chip grooves 7 which are close to the tool shank 1, and all the chip grooves of all the cutting sections are integrally arranged in a staggered and alternate mode. Each chip groove is fixedly provided with a cutting edge, and the circumferential cutting tracks of the cutting edges of each cutting section are the same. Each cutting edge is in a step shape which rises towards the direction of the cutter handle, and the circumferential cutting tracks of the cutting edges of the cutting sections are connected. An open arc-shaped blade groove is formed in the edge of the chip groove, and the cutting edge is fixed in the blade groove. All cutting edges are zero axial angle and zero radial angle, that is, the cutting edges are linear on the whole, so that the cutter has enough chip removal space, the machining rigidity and stability of the cutter are enhanced, and the phenomenon that the cutter is shaken due to the lateral stress of the main shaft is avoided.

With reference to fig. 2-4 of the specification, the taper hole cutting portion 2 includes two first front chip flutes 6 adjacent to the drill bit 1, two first rear chip flutes 7 adjacent to the shank 1, a first cutting edge 8, and a second cutting edge 9. The first front chip grooves 6 and the first rear chip grooves 7 are staggered and arranged alternately. Each first front chip flute 6 is provided with the first cutting edge 8, each first rear chip flute 7 is provided with the second cutting edge 9, the circumferential cutting tracks of the first cutting edges 8 are the same, and the circumferential cutting tracks of the second cutting edges 9 are the same. The first cutting edge 8 and the second cutting edge 9 are both in a step shape which rises towards the tool holder 1, and the circumferential cutting tracks of the first cutting edge 8 and the second cutting edge 9 are continuous (the cutting edges on the same side can also have overlapping transition on the cutting tracks). A first insert groove 10 is formed in the edge of the first front chip groove 6, and the first cutting edge 8 is fixed in the first insert groove 10. A second insert groove 11 is formed in the edge of the first rear chip groove 7, and the second cutting edge 9 is fixed in the second insert groove 11. The first insert pocket 10 and the second insert pocket 11 are both open circular arc shapes. The first cutting edge 8 and the second cutting edge 9 are both a zero-degree axial angle and a zero-degree radial angle, namely the cutting edges are linear on the whole, so that the influence of lateral cutting component on the machine tool spindle during cutting is avoided, the rigidity of the machine tool spindle is utilized to the maximum extent, and the tool shaking risk is reduced.

The chip groove of taper hole cutting part 2 adopts unique structure, first preceding chip groove 6 with first back chip groove 7 all designs into zero degree axial angle and zero degree radial angle, staggers alternate arrangement each other, and this kind of project organization makes the existing sufficient chip removal space of cutter make the chip removal smooth and easy in the course of working, can not remain the piece and possess sufficient processing rigidity again. All chip grooves of the taper hole cutting part 2 are internally provided with taper hole cutting part internal cooling holes 12, the taper hole cutting part internal cooling holes 12 are communicated with the main cooling liquid channel 5, and in order to ensure that the cooling liquid has enough pressure, the sum of the cross-sectional areas of all the internal cooling holes (including the first internal cooling hole 302 of the drill bit, the second internal cooling hole 303 of the drill bit and the taper hole cutting part internal cooling holes 12) is not larger than the cross-sectional area of the main cooling liquid channel. The 12 mouths of the inner cooling holes of the conical hole cutting parts are aligned to cutting edges of the PCD blades, and the cooling liquid can not only flush away chips, but also take away cutting heat, so that the processing temperature of the cutter is reduced, and the service life of the cutter is prolonged. The first cutting edge 8 and the second cutting edge 9 (PCD insert) of the conical hole cutting part 2 are both insert welded to the chip flute by means of brazing technique. The blade groove type is designed to be an open arc type, the welding strength of the blade is improved, the chip removal space of chips is increased, and the design structure can enable each cutting edge to exert the best processing advantage and avoid resonance to cause cutter vibration.

A first cutting edge 8 and a second cutting edge 9 of a PCD blade of the taper hole cutting part are used for cutting the PCD blade into step shapes by a slow wire processing technology, and each step can be set to be 2 mm-5 mm in length. The structure can disperse the cutting resistance to avoid the phenomena of difficult processing and tool vibration in the processing process, and can disperse the processing heat to avoid the phenomenon of cutting heat gathering and sharp points, thereby prolonging the service life of the cutter. Each step of the stepped cutting edge is cut into layer by layer in the machining process, the cutting edges are mutually supported, the machining resistance is reduced, the efficiency of removing machining allowance is greatly improved, and the subsequent finish machining of the taper hole can be efficiently finished only by matching with a common taper hole finish machining cutter.

In other embodiments, the cutting segments may be of one or more than two designs, depending on the depth of the countersink. In other embodiments, the number of the flutes in each cutting segment can be adjusted and designed according to the requirements of taper hole cutting, the diameter of the taper hole and the diameter of the tool on different materials, that is, the number of the first front flute and the first rear flute, which can be designed as one or more than two, and the first cutting edge and the second cutting edge thereon can be adjusted and designed.

The embodiment 1 provides a cutter for roughly machining a taper hole, and a special cutter structural design is provided for the machining characteristics of the taper hole, the cutter comprises a cutter handle, a taper hole cutting part and a drill bit which are sequentially connected, the drill bit can be pre-drilled, the first front chip removal groove and the first rear chip removal groove of the taper hole cutting part are staggered and alternately arranged, so that the machining process of each cutting edge of the cutter is not affected by each other, the phenomenon of cutter vibration caused by resonance is avoided, the cutting resistance is dispersed, the cutter vibration phenomenon is avoided, the first cutting edge and the second cutting edge are in a step shape which rises towards the direction of the cutter handle, the cutting resistance is dispersed, the cutter vibration phenomenon in the machining process is avoided, the machining heat can be dispersed, the phenomenon that the cutting heat is concentrated into a sharp point is avoided, and the service life of the cutter is prolonged; the chip removal grooves are staggered and arranged alternately, the chip removal space is large, chips are removed timely and smoothly, the chip removal of the taper hole cutting part and the chip removal of the drill bit cutting part are not influenced mutually, the metal removal rate is high, the machining efficiency is increased, and the machining cost of an enterprise is reduced.

In conclusion, the cutter has the advantages of compact structure, large chip removal space and good rigidity, all chip removal grooves are staggered alternately, the chip resistance is dispersed, the phenomenon of cutter vibration in machining caused by resonance is eliminated, and the allowance removal machining efficiency is improved; the step shape of the cutting edge is beneficial to heat dissipation, the service life of the cutter is prolonged, meanwhile, the requirement of processing takt is met, and the processing cost of a production enterprise is reduced.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the above description of the embodiments is only provided to help understand the method and the core concept of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A cutter for processing a taper hole is characterized by comprising a cutter handle, a taper hole cutting part and a drill bit which are sequentially connected,

the taper hole cutting part comprises at least one first front chip groove close to the drill bit, at least one first rear chip groove close to the cutter handle, a first cutting edge and a second cutting edge, and the first front chip groove and the first rear chip groove are staggered and alternately arranged;

each first front chip groove is provided with the first cutting edge, and each first rear chip groove is provided with the second cutting edge; the circumferential cutting tracks of the first cutting edges are the same, and the circumferential cutting tracks of the second cutting edges are the same;

the first cutting edge and the second cutting edge are both in a step shape which rises towards the direction of the tool shank, and the circumferential cutting tracks of the first cutting edge and the second cutting edge are continuous.

2. The tool for machining a tapered hole as set forth in claim 1, wherein said drill includes a drill tip and a drill body, said drill tip being located at a tip end of said drill body, drill chip flutes being formed on both sides of said drill tip; the drill bit flutes each extend from the tip to the base of the shank.

3. The tool for making a tapered bore according to claim 1, wherein the junction of said shank and said tapered bore cutting portion is configured as a curved surface.

4. The tool for machining a tapered hole as claimed in claim 1, wherein said tool for machining a tapered hole is provided with a main coolant channel along an axial core portion thereof, and said first front chip-discharging groove and said first rear chip-discharging groove are both provided therein with internal cooling holes communicated with said main coolant channel.

5. The tool for machining a tapered hole as claimed in claim 2, wherein the tool for machining a tapered hole is provided with a main coolant passage along an axial core portion thereof, and internal cooling holes communicated with the main coolant passage are formed in the first front chip groove and the first rear chip groove and on both sides of the drill tip.

6. The tool for machining a tapered hole as set forth in claim 4 or 5, wherein the sum of the sectional areas of all said internal cooling holes is not larger than the sectional area of said main coolant passage.

7. The tool for making a tapered hole as set forth in claim 1, wherein a first insert groove is provided on an edge of said first front chip groove, said first cutting edge being fixed in said first insert groove; a second blade groove is formed in the edge of the first rear chip groove, and the second cutting edge is fixed in the second blade groove; the first blade groove and the second blade groove are both open circular arc-shaped.

8. A cutter for processing a taper hole is characterized by comprising a cutter handle, a taper hole cutting part and a drill bit which are sequentially connected,

the taper hole cutting part comprises at least one cutting section, each cutting section comprises at least one chip removal groove uniformly arranged along the circumference, and all the chip removal grooves of all the cutting sections are integrally arranged in a staggered and alternate mode;

a cutting edge is fixed on each chip groove, and the circumferential cutting tracks of the cutting edges of each cutting section are the same;

each cutting edge is in a step shape which rises towards the direction of the cutter handle, and the circumferential cutting tracks of the cutting edges of the cutting sections are connected.

9. The tool for machining the taper hole as claimed in claim 8, wherein the drill comprises a drill tip and a drill body, the drill tip is located at the tip end of the drill body, and drill chip removal grooves are formed on two sides of the drill tip; the drill bit flutes each extend from the tip to the base of the shank.

10. The tool for making a tapered bore according to claim 8, wherein the junction of said shank and said tapered bore cutting portion is configured as a curved surface.

11. The tool for machining a tapered hole as set forth in claim 8, wherein said tool for machining a tapered hole is provided with a main coolant passage along an axial core portion thereof, and each of said flutes is provided therein with an internal cooling hole communicating with said main coolant passage.

12. The tool for taper hole machining according to claim 9, wherein said tool for taper hole machining is provided with a main coolant passage along an axial core portion thereof, and each of said chip grooves of said taper hole cutting portion and both sides of said drill tip are provided with an internal coolant hole communicating with said main coolant passage.

13. The tool for forming a tapered hole according to claim 11 or 12, wherein the sum of the cross-sectional areas of all said internal cooling holes is not larger than the cross-sectional area of said main coolant passage.

14. The tool for machining a tapered hole as set forth in claim 8, wherein an insert groove is provided on an edge of said chip groove, said cutting edge being fixed in said insert groove; the blade groove is of an open arc shape.