KR101164751B1

KR101164751B1 - Cutting tool assembly

Info

Publication number: KR101164751B1
Application number: KR20100100696A
Authority: KR
Inventors: 최창희
Original assignee: 대구텍 유한회사
Priority date: 2010-10-15
Filing date: 2010-10-15
Publication date: 2012-07-12
Also published as: KR20120039159A

Abstract

The cutting tool assembly according to the present invention includes a cutting head member having a cutting portion, a tool holder for supporting the cutting head member, and a fastening member for interconnecting the cutting head member and the tool holder. The cutting head member includes a cutting portion formed at the front end to perform cutting, a shank portion formed at the rear end and inserted into the tool holder, and an intermediate portion connecting the cutting portion and the shank portion. The shank portion of the cutting head member includes a truncated cone-shaped portion formed to narrow in the axial direction from the middle portion to the rear, and a cylindrical portion formed in a cylindrical shape in the axial direction at the rear end portion. The shank portion of the cutting head member is provided with a female screw portion for accommodating the first male screw portion of the fastening member along the axial direction at the center portion. The tool holder has a truncated cone-shaped opening formed at the front end to receive the truncated cone portion of the shank portion of the cutting head member, a cylindrical bore portion formed inside the truncated cone shape to accommodate the cylindrical portion of the cutting head member, and a cylindrical bore. And a through hole formed along the axial direction with a diameter smaller than the diameter of the portion. The through hole of the tool holder is provided with a female thread portion for accommodating the second male thread portion of the fastening member along the axial direction at the front end thereof. The fastening member has a first male screw portion for screwing with a female screw portion formed at the shank portion of the cutting head member at one end thereof, and a second male screw portion screwed with a female screw portion formed at the through hole of the tool holder at the other end portion thereof. have. In the cutting tool assembly according to the present invention, in the assembled state, the truncated cone-shaped portion of the shank portion of the cutting head member contacts the truncated cone-shaped opening of the tool holder, and the cylindrical portion of the shank portion of the cutting head member has a cylindrical bore portion of the tool holder. Configured to contact. Further, the cutting portion of the cutting head member of the cutting tool assembly according to the present invention is formed of cemented carbide material, and the shank portion of the cutting head member is formed of steel.

Description

Cutting tool assembly {CUTTING TOOL ASSEMBLY}

The present invention relates to a cutting tool assembly for cutting a workpiece. More specifically, the present invention relates to a cutting tool assembly capable of replacing a cutting head member having a cutting portion for cutting a workpiece.

The cutting portion of the cutting tool is typically formed of a material of high strength, such as cemented carbide, to cut the metal workpiece. In manufacturing a cutting tool, even if the non-cutting portion that does not perform the cutting process is formed of a high-strength material integrally with the cutting portion, the expensive high-strength material is used unnecessarily a lot, thereby increasing the manufacturing cost of the tool. Its high strength makes it difficult to manufacture cutting tools. In addition, since the cutting tool formed integrally in this way has to replace the cutting tool as a whole when the cutting portion wears out, the tool replacement cost is consumed a lot and it is not economical.

In order to solve this problem, a cutting tool assembly in which a cutting head member having a cutting portion and a tool holder for supporting the same are separately manufactured and then assembled and used are used. 7 illustrates a conventional cutting tool assembly 100 configured to be able to exchange cutting head members. As shown in FIG. 7, the cutting tool assembly 100 capable of replacing the cutting head member 110 may include a cutting head member 110 having a cutting portion 140 for performing a cutting process, and such a cutting head. And a tool holder 120 for supporting the member 110. The cutting head member 100 includes a cutting part 140 for performing a cutting process at one end and a shank part 150 inserted into and supported by the tool holder 120 at the other end. The shank portion 150 of the cutting head member 110 is mainly formed in a truncated cone shape so as to be inserted into the recess 125 of the tool holder 120 formed in a shape corresponding thereto.

This conventional cutting tool assembly 100, which can replace the cutting head member 110, has a truncated cone-shaped shank portion 150 formed in the cutting head member 110 in the tool holder 120. It is configured to support the cutting head member 110 in surface contact with the set 125. However, due to machining errors, the cone-shaped shank 150 formed in the cutting head member 110 and the cone-shaped recess 125 formed in the tool holder 120 can be manufactured in a completely corresponding shape. None, and this may cause a situation in which the cutting head member 110 is not firmly supported by the tool holder 120. That is, as shown in FIG. 7, the conventional cutting tool assembly 100 includes a cone-shaped shank portion 150 of the cutting head member 110 and a cone-shaped recess 125 of the tool holder 120. In some cases, contact with only a part of the shank portion 150 (for example, the tip end portion of the shank portion 150) may not be provided, so that sufficient support force may not be provided to the cutting head member 110.

Moreover, the cutting head member 110 is difficult to process because it is formed of a high-strength material such as cemented carbide in order to provide sufficient strength for cutting the metal workpiece to the cutting portion 140 which performs the cutting process. This makes it more difficult to manufacture the shank portion 150 in a shape that perfectly corresponds to the shape of the recess 125 of the tool holder 120. In addition, the shank portion 150 formed of a high-strength material is not easy to expand and does not provide a sufficiently firm coupling force between the shank portion 150 and the recess 125 of the tool holder 120.

The present invention solves the above-mentioned problems of the conventional cutting tool assembly which can replace the cutting head, thereby improving the contact supporting force between the cutting head member and the tool holder, making it easier to manufacture while supporting the cutting head member more firmly. It is an object of the present invention to provide a cutting tool assembly that can.

The cutting tool assembly according to the present invention includes a cutting head member having a cutting portion, a tool holder for supporting the cutting head member, and a fastening member for interconnecting the cutting head member and the tool holder.

The cutting head member includes a cutting portion formed at the front end to perform cutting, a shank portion formed at the rear end and inserted into the tool holder, and an intermediate portion connecting the cutting portion and the shank portion. The shank portion of the cutting head member includes a truncated cone-shaped portion formed to narrow in the axial direction from the middle portion to the rear, and a cylindrical portion formed in a cylindrical shape in the axial direction at the rear end portion. The shank portion of the cutting head member is provided with a female screw portion for accommodating the first male screw portion of the fastening member along the axial direction at the center portion.

The tool holder has a truncated cone-shaped opening formed at the front end to receive the truncated cone portion of the shank portion of the cutting head member, a cylindrical bore portion formed inside the truncated cone shape to accommodate the cylindrical portion of the cutting head member, and a cylindrical bore. And a through hole formed along the axial direction with a diameter smaller than the diameter of the portion. The through hole of the tool holder is provided with a female thread portion for accommodating the second male thread portion of the fastening member along the axial direction at the front end thereof.

The fastening member has a first male screw portion for screwing with a female screw portion formed at the shank portion of the cutting head member at one end thereof, and a second male screw portion screwed with a female screw portion formed at the through hole of the tool holder at the other end portion thereof. have.

In the cutting tool assembly according to the present invention, in the assembled state, the truncated cone-shaped portion of the shank portion of the cutting head member contacts the truncated cone-shaped opening of the tool holder, and the cylindrical portion of the shank portion of the cutting head member has a cylindrical bore portion of the tool holder. Configured to contact.

Further, the cutting portion of the cutting head member of the cutting tool assembly according to the present invention is formed of a cemented carbide material such as tungsten, and the shank portion of the cutting head member is formed of steel.

Cutting tool assembly according to an embodiment of the present invention, preferably, the outer diameter of the first male screw portion of the fastening member screwed to the female thread formed on the shank portion of the cutting head member and the cylindrical portion of the shank portion of the cutting head member The thickness between outer diameters is larger than 0.05 times the outer diameter of the cylindrical portion of the shank portion, and smaller than 0.2 times the outer diameter of the cylindrical portion of the shank portion.

The cutting tool assembly according to another embodiment of the present invention preferably has a straight line in which the rod flank of the screw engaging portion, in which the female screw portion formed in the shank portion of the cutting head member and the first male screw portion of the fastening member, is screwed, is perpendicular to the axial direction. And 30 degrees to 50 degrees.

Further, in the cutting tool assembly according to another embodiment of the present invention, the axial length of the intermediate portion of the cutting head member is formed to be larger than 0.1 times the outer diameter of the cutting portion.

The cutting tool assembly according to the present invention is formed by dividing the shape of the shank portion of the cutting head member into a truncated cone shape and a cylindrical shape so as to be accommodated in each of the truncated cone-shaped opening and the cylindrical bore of the tool holder, thereby the cutting tool assembly is assembled. When the cutting head member and the tool holder are contacted at both ends of the shank portion, the cutting head member can be supported more firmly.

In addition, in the cutting tool assembly according to the present invention, the cutting portion to perform the cutting process is formed of a high-strength hard material such as tungsten, and the shank portion that does not perform the cutting process is made of ordinary steel of lower strength By forming, the shape of the shank portion can be easily machined while providing the cutting portion with sufficient strength to machine the metal material. In addition, since the cutting tool assembly according to the present invention forms the shank portion for expansion coupling with the tool holder, the shank portion can be expanded more easily, so that the shank portion and the tool holder have a more firm contact bearing force. Can be provided.

Furthermore, a cutting tool assembly according to the present invention is provided between an outer diameter of a first male threaded portion of a fastening member screwed with a female threaded portion formed on the shank portion of the cutting head member, and an outer diameter of the cylindrical portion of the shank portion of the cutting head member. By forming the thickness smaller than 0.2 times the outer diameter of the cylindrical portion of the shank portion, the shank portion of the cutting head member can be more easily expanded and coupled with the tool holder.

In addition, the cutting tool assembly according to the present invention is a straight line in which the rod flank of the screw coupling portion to which the female screw portion formed in the shank portion of the cutting head member and the first male screw portion of the fastening member is screwed is perpendicular to the axial direction, and is 30 degrees to 50 degrees. By forming at an angle of view, the shank portion of the cutting head member can be expanded and coupled with the tool holder more easily.

Further, in the cutting tool assembly according to the present invention, the axial length of the intermediate portion of the cutting head member is formed to be larger than 0.1 times the outer diameter of the cutting portion of the cutting head member, thereby precisely performing diffusion bonding of the cutting portion and the shank portion. It is possible to form the cutting portion and the shank portion of different materials.

1 is an exploded perspective view of a cutting tool assembly according to the present invention.
2 and 3 show a cross sectional view of the cutting tool assembly according to the invention in an assembled state.
4 shows a cross section of a threaded portion between a cutting head member and a fastening member of a cutting tool assembly according to the invention.
5 illustrates a screwed state of the cutting head member and the fastening member of the cutting tool assembly according to an embodiment of the present invention.
6A and 6B are cross-sectional views illustrating a state in which a cutting head member and a fastening member are assembled in a cutting tool assembly according to an embodiment of the present invention.
7 is a cross-sectional view showing a conventional cutting tool assembly capable of replacing a cutting head member having a cutting portion formed thereon.

Hereinafter, the cutting tool assembly 1 according to the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a cutting tool assembly 1 according to the invention, and FIGS. 2 and 3 show a state in which the cutting tool assembly 1 is assembled.

The cutting tool assembly 1 includes a cutting head member 10 having a cutting portion, a tool holder 20 supporting the cutting head member 10, and a cutting head member 10 and the tool holder 20 interconnected with each other. It includes a fastening member 30.

One end of the cutting head member 10 is formed with a cutting portion 40 for performing a cutting process. The cutting portion 40 is preferably formed of a cemented carbide material such as tungsten carbide so as to cut the metal workpiece. At the other end of the cutting head member 10, a shank portion 50 inserted into the tool holder 20 to support the cutting head member 10 to the tool holder 20 includes a cutting portion 40 and a shank portion 50. It is formed with the intermediate portion 60 for connecting. The shank portion 50 includes a truncated cone shaped portion 51 formed in a truncated cone shape and a cylindrical portion 52 formed in a cylindrical shape. As shown in FIG. 2, when the cutting tool assembly 1 is assembled, the cone-shaped portion 51 of the shank portion 50 is received and supported by a cone-shaped opening 21 formed in the tool holder 20. The cylindrical portion 52 of the shank portion 50 is received and supported by the cylindrical bore portion 22 formed in the tool holder 20. In addition, the shank portion 50 of the cutting head member 10 includes a female thread portion 53 for screwing with the first male thread portion 31 of the fastening member 30 along the axial direction.

The shank portion 50 and the intermediate portion 60 of the cutting tool assembly 1 according to the invention are preferably of a material different from the cutting portion 40 (for example, a plain steel having a lower strength than the cutting portion 40). Material]. In the cutting tool assembly 1 according to the present invention, the cutting part 40 performing the cutting process is formed of a cemented carbide material such as tungsten, and the shank part 50 and the intermediate part 60 which do not perform the cutting process are general. After forming into steel, they may be formed by joining by a method such as diffusion bonding. When the shank portion 50 of the cutting head member 10 is formed of a high-strength cemented carbide material such as the cutting portion 40, it is difficult to process the shape of the shank portion 50 due to the high strength of the material, the cutting process The non-cutting portion that does not perform the expensive material is formed to increase the manufacturing cost. In addition, since the cutting head member 10 has a high strength of the shank portion 50, even when the fastening member 60 is coupled to the shank portion 50, sufficient expansion does not occur in the shank portion 50. Sufficient expansion coupling is not provided between the shank portion 50 and the tool holder 20. Therefore, the cutting tool assembly 1 according to the present invention, the cutting portion 40 for performing the cutting process is formed of a high strength hard material such as tungsten (hard material), the shank portion 50 does not perform the cutting process Is formed of a lower strength general steel, to provide sufficient strength to the cutting portion 40, while at the same time easy to process the shank portion 50 and expansion expansion coupling with the tool holder 20 It consists.

The tool holder 20 of the cutting tool assembly 1 according to the present invention has a cylindrical through hole 23 extending in the axial direction therein. Moreover, the tool holder 20 is equipped with the truncated cone-shaped opening part 21 which accommodates the truncated cone-shaped part 51 formed in the shank part 50 of the cutting head member 10 in the front end part. The cone-shaped opening 21 contacts the cone-shaped portion 51 formed in the shank portion 50 of the cutting tool head 10 when the cutting tool assembly 1 is assembled, so that the front of the shank portion 50 is closed. The cutting head member 10 in contact with the tool holder 20. In addition, the tool holder 20 has a cylindrical bore portion 22 into which a cylindrical portion 52 formed in the shank portion 50 of the cutting head member 10 is inserted inside the cone-shaped opening portion 51 formed at the front end. ) Is formed along the axial direction. This cylindrical bore portion 22 comes into contact with the cylindrical portion 52 formed in the shank portion 50 of the cutting head member 10 when the cutting tool assembly 1 is assembled, so that the rear of the shank portion 50 is provided. The cutting head member 10 in contact with the tool holder 20. As such, the cutting tool assembly 1 according to the present invention is formed by dividing the shank portion 50 of the cutting head member 10 into a truncated cone portion 51 and a cylindrical portion 52, respectively, of the tool holder 20. In the case where the shape of the shank portion 50 and the tool holder 20 does not correspond exactly due to machining error as shown in FIG. 3 by being accommodated in the cone-shaped opening 21 and the cylindrical bore portion 22. In addition, the cutting head member 10 and the tool holder 20 are contacted at both ends of the shank portion 50, so that the cutting head member 1 can be supported more firmly.

On the other hand, at the front end of the through hole 23 formed in the tool holder 20, a female screw portion 24 for screwing with the second male screw portion 32 of the fastening member 30 is formed.

The fastening member 30 is formed in the shaft shape extended along an axial direction. The fastening member 30 has a first male thread portion 31 which is screwed into the female thread portion 53 formed on the shank portion 50 of the cutting head member 10 at one end thereof, and has a tool holder at the other end thereof. A second male screw portion 32 is formed to screw into the female screw portion 24 formed in the through hole 23 of the 20. The cutting head member 10 and the tool holder 20 of the cutting tool assembly 1 are fastened to each other by screwing the female threads 53 and 24 and the male threads 31 and 32.

4 shows a cross-section of the cutting head member 10 and the fastening member 30 of the cutting tool assembly 1 according to an embodiment of the present invention. As shown in FIG. 4, the cutting tool assembly 1 according to the present embodiment has a thickness T of the cylindrical portion 52 formed on the shank portion 50 of the cutting head member 10, that is, the fastening member ( The thickness between the outer diameter of the first male screw portion 31 engaged with the cutting head member 10 of 30 and the outer diameter D2 of the cylindrical portion 52 of the cutting head member 10 is the cutting head member 10. It is preferable that the cylindrical portion 52 of the shank portion 50) be larger than 0.05 times and smaller than 0.2 times the outer diameter D2. If the thickness T between the outer diameter D2 of the cylindrical portion 52 of the shank portion 50 and the outer diameter of the first male thread portion 31 of the fastening member 30 is equal to the outer diameter of the cylindrical portion 52. When the thickness is smaller than 0.05 times (D2), the thickness becomes too small and the rigidity of the shank portion 50 becomes too weak, and conversely, the outer diameter D2 of the cylindrical portion 52 of the shank portion 50 and the fastening member ( If the thickness T between the outer diameters of the first male threaded portions 31 of 30 is greater than 0.2 times the outer diameter D2 of the cylindrical portion 52, the shank portion at the time of assembling the cutting tool assembly 1 50 does not expand well so that sufficient expansion engagement does not occur between the shank portion 50 and the tool holder 20, which prevents the cutting head member 10 from being firmly supported by the tool holder 20. Therefore, the cutting tool assembly 1 according to the present invention has a thickness (between the outer diameter D2 of the cylindrical portion 52 of the shank portion 50 and the outer diameter of the first male thread portion 31 of the fastening member 30). T) is formed between 0.05 times and 0.2 times the outer diameter D2 of the cylindrical portion 52.

5 shows that the female thread portion 53 formed on the shank portion 50 of the cutting head member 10 of the cutting tool assembly 1 according to the present invention and the first male thread portion 31 of the fastening member 30 are screwed. The combined state is shown. As shown in FIG. 5, the female thread part 53 formed in the cutting head member 10 and the first male thread part 31 formed in the fastening member 30 may be formed in various thread shapes. However, the female screw portion 53 of the cutting head member 10 and the first male screw portion 31 of the fastening member 30 are in contact with each other at the time of screwing, so that the rod flank contact surfaces 53a and 31a support the axial load. It is preferably formed so as to form an angle between 30 and 50 degrees with a straight line perpendicular to this axial direction. If the rod flank contact surfaces 53a; 31a of the screw coupling portion are formed at a straight line perpendicular to the axial direction and at an angle smaller than 30 degrees, the shank portion 50 and the tool holder 20 when assembling the cutting tool assembly 1 are assembled. Expansion contact is less likely to occur. On the contrary, when the rod flank contact surfaces 53a and 31a are formed at an angle greater than 50 degrees with a straight line perpendicular to the axial direction, the coupling force of the screw coupling is weakened and the assembly state of the cutting tool assembly 1 becomes unstable. Therefore, the cutting tool assembly according to the present invention is such that the rod flank contact surfaces 53a; 31a of the screw coupling portion form an angle between 30 and 50 degrees with a straight line perpendicular to the axial direction.

6A and 6B show a state in which the cutting head member 10 and the fastening member 30 of the cutting tool assembly 1 are assembled according to an embodiment of the present invention. As described above, the cutting head member 10 of the cutting tool assembly 1 according to the present embodiment includes a cutting part 40 formed of a cemented carbide material such as tungsten, a shank part 50 formed of steel, and an intermediate part 60. ) Are formed separately, and then bonded to each other by diffusion bonding or the like. In such a cutting head member 10, when the intermediate portion 60 formed of a relatively low strength steel is formed thinly, the intermediate portion 60 is thermally deformed by heat generated during diffusion bonding, and thus the cutting portion ( It may occur that a uniform bonding between 40) and the intermediate portion 60 is not achieved. In order to avoid this problem, the cutting tool assembly 1 according to the invention has a minimum value of the axial length A of the intermediate portion 60 of the cutting head member 10 as shown in FIGS. 6A and 6B. It is preferable to be formed so that it may become larger than 0.1 times the outer diameter D1 of this cutting part 40. FIG.

The above-described embodiments of the present invention are presented for illustrative purposes only and do not limit or limit the present invention. Those skilled in the art may apply various modifications and modifications to the present invention without departing from the scope of the present invention.

10: cutting head member
20 tool holder
21: opening of the cone shape
22: cylindrical bore
23: through hole
24: female thread
30: fastening member
31: first male thread portion of the fastening member
31a: Rod flank contact surface of the male thread formed on the fastening member
32: second male thread portion of the fastening member
40: cutting part
50: shank part
51: cone shape
52: cylindrical shape
53: female thread
53a: rod flank contact surface of female thread formed on shank
60: middle part
A: axial length of the middle part
T: thickness of the cylindrical portion of the shank portion
D1: outer diameter of cutting part
D2: outer diameter of the cylindrical portion of the shank portion

Claims

A cutting tool assembly comprising a cutting head member, a tool holder supporting the cutting head member, and a fastening member interconnecting the cutting head member and the tool holder,
The cutting head member may include a cutting portion of a cemented carbide material formed at a front end to perform cutting, an intermediate shank portion formed at a rear end to be inserted into a tool holder, and an intermediate portion connecting the cutting part and the shank part. Including wealth,
The shank portion of the cutting head member includes a truncated cone-shaped portion formed to narrow in the axial direction from the middle portion to the rear, and a cylindrical portion formed in a cylindrical shape in the axial direction at the rear end portion, A female screw portion for receiving the first male screw portion of the fastening member is formed,
The tool holder has a truncated cone-shaped opening formed at the front end to receive the truncated cone-shaped portion of the shank portion of the cutting head member, and a cylindrical beam formed inside the truncated cone-shaped opening to accommodate the cylindrical portion of the cutting head member. And a through hole formed along the axial direction with a diameter smaller than the diameter of the cylindrical bore portion, the front end of the through hole having a female screw portion for receiving the second male screw portion of the fastening member along the axial direction; ,
In the state where the cutting tool assembly is assembled, the conical portion of the shank portion of the cutting head member is in contact with the cone-shaped opening of the tool holder, and the cylindrical portion of the shank portion of the cutting head member is in contact with the cylindrical bore portion of the tool holder. Cutting tool assembly.

The method of claim 1,
The thickness between the outer diameter of the first male screw portion of the fastening member screwed with the female screw portion formed on the shank portion of the cutting head member and the outer diameter of the cylindrical portion of the shank portion of the cutting head member is the outer diameter of the cylindrical portion of the shank portion. A cutting tool assembly greater than 0.05 times and less than 0.2 times the outer diameter of the cylindrical portion of the shank portion.

The method of claim 1,
And a rod flank of the screw coupling portion for screwing the female screw portion formed in the shank portion of the cutting head member and the first male screw portion of the fastening member is formed at an angle of 30 to 50 degrees with a straight line perpendicular to the axial direction.

The method of claim 1,
And a axial length of the intermediate portion of the cutting head member is greater than 0.1 times the outer diameter of the cutting portion of the cutting head member.