WO2022108128A1

WO2022108128A1 - Cryogenic cutting tool kit

Info

Publication number: WO2022108128A1
Application number: PCT/KR2021/014509
Authority: WO
Inventors: 김동민; 강성욱
Original assignee: 한국생산기술연구원
Priority date: 2020-11-23
Filing date: 2021-10-18
Publication date: 2022-05-27
Also published as: KR20220070872A; KR102477395B1

Abstract

A cryogenic cutting tool kit according to an embodiment of the present invention may comprise: a housing having a hollow portion which is formed inside the housing and having an injection hole which is formed at the outer surface of the housing and through which a cryogenic coolant is injected; a tool holder inserted into the hollow portion, having an end to which a processing tool is coupled, and having a supply channel which is formed in the axial direction inside the tool holder to communicate with the hollow portion and through which the cryogenic coolant is supplied to the processing tool side; and a bearing disposed in the hollow portion and coupled to the outer surface of the tool holder, wherein the tool holder includes a pattern portion which is formed on the inner surface of the supply channel to stabilize the flow of the cryogenic coolant.

Description

Cryogenic cutting toolkit

The present invention relates to a cutting toolkit for cryogenic use.

In general, heat is generated in the process of machining a workpiece, and this causes deformation or damage to the workpiece or wear and deformation of tools. To prevent this, coolant is supplied as a coolant.

In recent years, the processing of difficult-to-cut materials such as titanium, Inconel, and CGI, which can realize this, is increasing according to the lightweight, eco-friendly, and high-efficiency of high-tech industries such as automobiles and aerospace.

However, the high-temperature cutting heat and thermal deformation of the tool occurred in these difficult-to-cut materials due to characteristics such as lower thermal conductivity and high strength than conventional metals. Accordingly, cryogenic fluid such as -196°C liquid nitrogen (LN2) is used as the refrigerant instead of the conventional cutting oil to improve the cooling effect when processing difficult-to-cut materials.

However, due to the low temperature of the cryogenic fluid, the lubricant and oil of the bearings disposed in the toolkit are overcooled, so that the tool does not rotate, so productivity is reduced, and the cryogenic fluid leaks to the outside and affects the surrounding components. .

In addition, when the cryogenic fluid is supplied to the tool through the toolkit, the flow becomes unstable due to the bending of the flow path, and the pressure of the cryogenic fluid is not constant, so there is a problem in that the cooling effect is reduced.

It was devised based on the technical background as described above, and it is to provide a cutting toolkit for cryogenics that can improve cooling efficiency by stabilizing the flow of cryogenic refrigerant.

A cryogenic cutting toolkit according to an embodiment of the present invention includes a housing having a hollow portion formed therein, an injection hole into which a cryogenic refrigerant is injected on an outer surface, inserted into the hollow portion and a machining tool is coupled to the end, It is formed along the axial direction therein and includes a tool holder for supplying the cryogenic refrigerant to the processing tool through a supply passage communicating with the hollow part, and a bearing disposed in the hollow part and coupled to the outer surface of the tool holder, , The tool holder may include a pattern portion formed on the inner surface of the supply passage to stabilize the flow of the cryogenic refrigerant.

The pattern portion may extend along a longitudinal direction of the supply passage, and a plurality of pattern portions may be disposed along the circumference of the supply passage.

The pattern portion may be formed in a spiral shape along the inner circumference of the supply passage.

In the pattern part, inclined surfaces inclined toward the inner surface of the supply passage may be formed at both ends.

The pattern portion may have a triangular cross-section.

The tool holder may include a guide groove formed along the circumferential direction of the outer surface and a delivery passage extending from the guide groove toward the supply passage to deliver the cryogenic refrigerant in the hollow portion to the supply passage.

The hollow part may further include a sealing part disposed on one side of the bearing and coupled to the outer surface of the processing tool.

The bearing may be coated with a PTFE material.

A stopper coupled to the end of the housing and passing through the tool holder through the center may further include a stopper sealing the end of the hollow part.

The stopper may have a second seating groove extending along the circumferential direction on the inner surface to insert the sealing part.

The cryogenic cutting toolkit according to an embodiment of the present invention can improve cooling efficiency by stabilizing the flow of cryogenic refrigerant.

The cryogenic cutting toolkit according to an embodiment of the present invention can prevent cooling of the cryogenic refrigerant due to low temperature by applying a material capable of self-lubrication.

The cryogenic cutting toolkit according to an embodiment of the present invention can improve durability and stability by preventing the outflow of cryogenic refrigerant to the outside.

1 is a perspective view of a cutting toolkit for cryogenic use according to an embodiment of the present invention.

2 is an exploded perspective view of a cutting toolkit for cryogenic use according to an embodiment of the present invention.

3 is a cross-sectional view taken along line A-A' of the second body shown in FIG. 2 .

4 is a cross-sectional view of the cryogenic cutting toolkit shown in FIG. 1 .

5 is an enlarged view of the cryogenic cutting toolkit shown in FIG.

6 is a cross-sectional view illustrating a first modified example of the second body shown in FIG. 3 .

FIG. 7 is a cross-sectional view illustrating a first modified example of the cryogenic cutting toolkit shown in FIG. 4 .

8 is a cross-sectional view illustrating a second modified example of the second body shown in FIG. 3 .

9 is a cross-sectional view illustrating a second modified example of the cryogenic cutting toolkit shown in FIG. 4 .

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present invention is not necessarily limited to the illustrated bar.

In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

1 is a perspective view of a cryogenic cutting toolkit according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a cryogenic cutting toolkit according to an embodiment of the present invention, and FIG. 3 is the second body shown in FIG. A-A' cross-sectional view, FIG. 4 is a cross-sectional view of the cryogenic cutting toolkit shown in FIG.

As shown in FIG. 1 , in the stopper 600 , the housing 100 side is defined as the upper side, and the stopper 600 side is defined as the lower side in the housing 100 .

1 and 2 , a cryogenic cutting toolkit 10 according to an embodiment of the present invention includes a housing 100 , a tool holder 200 , a coupling part 300 , a bearing 400 , and a stopper 600 . ) may be included.

The housing 100 is formed in a cylindrical shape, and a hollow part 110 may be formed therein in the axial direction. The hollow part 110 may be formed through the upper and lower surfaces of the housing 100 .

The outer surface of the housing 100 is formed to extend to the hollow portion 110, the injection hole 120 into which the cryogenic refrigerant is injected may be formed. For example, a hose (not shown) for supplying cryogenic refrigerant may be connected to the injection hole 120 , and thus cryogenic refrigerant may be supplied to the hollow part 110 through the injection hole 120 .

In addition, the first coupling hole 130 may be formed in the lower surface of the housing 100 . For example, a plurality of first coupling holes 130 may be spaced apart from each other along the lower surface of the housing 100 . A stopper 600 to be described later may be coupled to the first coupling hole 130 through a fastening member such as a bolt or a rivet.

The tool holder 200 may include a first body 210 and a second body 220 .

The first body 210 may have a predetermined cylindrical shape, and a second body 220 may be formed at a lower portion thereof. The first body 210 is inserted into the hollow part 110 and may be located at an upper end of the hollow part 110 . For example, the first body 210 may be fixed to the upper end of the hollow part 110 , and may protrude by a predetermined length from the upper surface of the housing 100 . A coupling part 300 to be described later may be coupled to the upper end of the first body 210 .

The second body 220 may be connected to the center of the lower surface of the first body 210 in a predetermined cylindrical shape. For example, a diameter of the second body 220 may be smaller than a diameter of the first body 210 and a diameter of the hollow part 110 .

The second body 220 is inserted into the hollow part 110, and accordingly, when the first body 210 is fixed to the upper end of the hollow part 110 and the tool holder 200 is coupled to the housing 100, A lower end of the second body 220 may protrude out of the housing 100 by a predetermined length. A processing tool (not shown) may be coupled to the lower end of the second body 220 . For example, the machining tool may be a machining tool for cutting an object.

In addition, referring to FIGS. 3 and 4 , the second body 220 may include a guide groove 221 , a delivery passage 222 , and a supply passage 223 .

The guide groove 221 may be formed along the circumferential direction of the outer surface of the second body 220 . For example, the guide groove 221 may be formed at a position corresponding to the injection hole 120 . Cryogenic refrigerant may be filled along the guide groove 221 .

The transmission passage 222 may be formed to extend inwardly from the outer surface of the second body 220 . For example, the transmission flow path 222 may be formed in the guide groove 221 and extend toward the central axis of the second body 220 . The cryogenic refrigerant moved through the injection hole 120 and the hollow part 110 may be introduced into the delivery passage 222 . On the other hand, since the guide groove 221 is filled with the cryogenic refrigerant, even when the second body 220 rotates, the cryogenic refrigerant can easily flow into the delivery passage 222 side.

The supply passage 223 may be formed along the axial direction from the center of the second body 220 . In this case, the upper end of the supply passage 223 may be connected to the delivery passage 222 . Accordingly, the supply passage 223 may supply the cryogenic refrigerant introduced from the delivery passage 222 in the direction of the lower processing tool. In addition, a pattern portion 225 to be described later may be formed on the inner surface of the supply passage 223 .

The tool holder 200 may be connected to the spindle of the machine tool through the coupling unit 300 to rotate. Accordingly, while the machining tool fixed to the second body 220 rotates, it is possible to cut the object.

1, 2 and 4 , the coupling part 300 may be coupled to the upper end of the tool holder 200 . Specifically, the coupling part 300 may be coupled to the upper end of the first body 210 . The coupling unit 300 may transmit the rotational force of the spindle to the tool holder 200 by coupling the tool holder 200 to the spindle (not shown) of the machine tool. That is, the tool holder 200 may be connected to the spindle of the machine tool through the coupling unit 300 to rotate.

2 and 4 , the bearing 400 may be disposed in the hollow part 110 and coupled to the tool holder 200 to rotate the tool holder 200 . The bearing 400 is formed in plurality, each of which may be disposed at the upper and lower portions of the hollow part 110 . In this case, each bearing 400 may be coupled to the outer surface of the tool holder 200 and the second body 220 .

The bearing 400 may be a ball bearing coated with a PTFE (Teflon) material. Accordingly, the bearing 400 is self-lubricated during friction with the tool holder 200 by the PTFE coating, so that it can rotate without being frozen by the cryogenic refrigerant.

The sealing part 500 may be disposed in the hollow part 110 and coupled to the tool holder 200 . For example, the sealing part 500 is formed in plurality, and each may be disposed on one side of the bearing 400 . Accordingly, the sealing part 500 prevents the outflow of the cryogenic refrigerant through between the housing 100 and the bearing 400 , thereby improving the durability and stability of the cutting toolkit 10 .

As another example, the sealing part 500 is a first seating groove 112 formed at a position facing the first body 210 on the inner surface of the housing 100 or a through part 610 of the stopper 600 to be described later. It may be additionally disposed in the second seating groove 612 formed on the side surface.

2 and 4 , the stopper 600 may be coupled to the lower surface of the housing 100 in a plate shape having a ring-shaped cross-section. The stopper 600 has a penetrating portion 610 formed in the center thereof, and the second body 220 may be penetrated through the through portion 610 . A second seating groove 612 may be formed on the inner surface of the through portion 610 to provide the above-described sealing portion 500 .

In addition, the stopper 600 may have a second coupling hole 630 penetrating the upper and lower surfaces. For example, a plurality of second coupling holes 630 may be disposed to be spaced apart from each other along the circumference of the through portion 610 . As another example, the first coupling hole 130 of the housing 100 and the second coupling hole 630 of the stopper 600 may correspond. Accordingly, by inserting the fastening member through the second coupling hole 630 and the first coupling hole 130 , the stopper 600 may be coupled to the housing 100 .

This stopper 600 closes the lower surface of the hollow part 110 to prevent the outflow of cryogenic refrigerant, while preventing the components installed inside the housing from being separated.

5 is an enlarged view of the cryogenic cutting toolkit shown in FIG.

Referring to FIG. 5 , the pattern part 225 is formed to protrude on the inner surface of the supply passage 223 and may rub against the cryogenic refrigerant. For example, the pattern part 225 may have a shape extending along the longitudinal direction of the supply passage 223 . As another example, inclined surfaces 226 inclined toward the inner surface of the supply passage 223 may be formed at both ends of the pattern portion 225 . Accordingly, both ends of the pattern portion 225 may be gently formed to facilitate the inflow and outflow of cryogenic refrigerant.

In addition, a plurality of pattern parts 225 may be disposed to be spaced apart from each other along the inner surface of the supply passage 223 . The pattern portion 225 may stabilize the flow of cryogenic refrigerant flowing into the supply passage 223 through the delivery passage 222 .

Specifically, since the direction of the cryogenic refrigerant is rapidly changed while flowing from the delivery flow path 222 to the supply flow path 223, the flow of the cryogenic refrigerant becomes unstable and a pulsation phenomenon in which it is supplied at an uneven pressure occurred. In addition, when the flow direction of the cryogenic refrigerant is rapidly changed, turbulence is formed and the temperature of the refrigerant increases and vaporizes easily, making it difficult to deliver the cryogenic refrigerant to the object in a liquid state.

At this time, by forming the pattern portion 225 in the supply passage 223 , friction with the cryogenic refrigerant flowing into the supply passage 223 is generated to prevent turbulence, thereby stabilizing the flow. That is, the pattern part 225 can stabilize the flow of cryogenic refrigerant to maintain a liquid state, and can supply a uniform pressure to the processing tool, thereby improving cooling efficiency and working efficiency.

6 is a cross-sectional view illustrating a first modified example of the second body shown in FIG. 3 , and FIG. 7 is a cross-sectional view illustrating a first modified example of the cryogenic cutting toolkit illustrated in FIG. 4 .

6 and 7 , the pattern part 225 according to the first modified example is formed to protrude on the inner surface of the supply passage 223 and may rub against the cryogenic refrigerant. For example, the pattern part 225 may have a shape extending along the longitudinal direction of the supply passage 223 . Also, the cross-section of the pattern part 225 may be formed in a triangular shape.

8 is a cross-sectional view illustrating a second modified example of the second body shown in FIG. 3 , and FIG. 9 is a cross-sectional view illustrating a second modified example of the cryogenic cutting toolkit shown in FIG. 4 .

Referring to FIGS. 8 and 9 , the pattern part 225 according to the second modified example is spirally formed along the periphery on the inner surface of the supply passage 223 to rub against the cryogenic refrigerant. For example, the pattern portion 225 may be formed to extend from one end of the supply passage 223 to the other end. Accordingly, the pattern unit 225 may stabilize the flow of the cryogenic refrigerant by inducing the cryogenic refrigerant introduced into the supply passage 223 to flow in a rotational form.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same spirit. , changes, deletions, additions, etc. may easily suggest other embodiments, but this will also fall within the scope of the present invention.

Claims

a housing having a hollow portion formed therein and an injection hole through which a cryogenic refrigerant is injected on an outer surface thereof;

a tool holder inserted into the hollow part and coupled to an end of the processing tool, the tool holder being formed along the axial direction therein and supplying the cryogenic refrigerant to the processing tool side through a supply passage communicating with the hollow part; and

and a bearing disposed in the hollow part and coupled to the outer surface of the tool holder,

The tool holder is

A cryogenic cutting toolkit including a pattern part formed on the inner surface of the supply passage to stabilize the flow of the cryogenic refrigerant.
The method of claim 1,

The pattern part,

A cutting toolkit for cryogenic temperatures protruding along the longitudinal direction of the supply flow path, the plurality of which are disposed along the circumference of the supply flow path.
The method of claim 1,

The pattern part,

A cutting toolkit for cryogenic temperatures that is spirally formed along the periphery of the inner surface of the supply passage.
3. The method of claim 2,

The pattern part,

A cutting toolkit for cryogenic temperatures in which inclined surfaces inclined toward the inner surface of the supply passage are formed at both ends.
3. The method of claim 2,

The pattern part,

Cryogenic cutting toolkit with a triangular cross section.
The method of claim 1,

The tool holder is

a guide groove formed along the circumferential direction of the outer surface; and

Cryogenic cutting tool kit including a delivery flow path extending from the guide groove toward the supply flow path to deliver the cryogenic refrigerant of the hollow part to the supply flow path.
The method of claim 1,

Cryogenic cutting tool kit disposed on one side of the bearing in the hollow portion, further comprising a sealing portion coupled to the outer surface of the machining tool.
The method of claim 1,

The bearing is

Cryogenic cutting toolkit coated with PTFE material.
8. The method of claim 7,

Cryogenic cutting toolkit coupled to the end of the housing and passing through the tool holder in the center, further comprising a stopper for sealing the end of the hollow part.
10. The method of claim 9,

The stopper is

A cryogenic cutting toolkit having a second seating groove extending along the circumferential direction on the inner surface into which the sealing part is inserted.