KR20200081780A - Cutting tool - Google Patents

Abstract

According to one embodiment of the present invention, a cutting tool comprises: a tool body which has a cutting insert mounted thereon; and a coolant spray unit which sprays coolant towards the center of the cutting insert, and is fixed on the tool body by a fastening bolt. The coolant spray unit includes a coolant channel which connects a coolant inlet and a coolant outlet. The coolant channel includes: a first curved section from the coolant inlet to the coolant outlet; a first straight section next to the first curved section; a second curved section next to the first straight section; and a second straight section next to the second curved section. The coolant channel′s cross-sectional area gets small and then large again from the coolant inlet to the coolant outlet. The coolant inlet is in a circular shape, and the coolant outlet is in an oval shape which is longer in the transversal direction than in the longitudinal direction. The cutting tool is able to increase the volume of coolant and to prevent the coolant from spreading.

Description

Cutting tool {Cutting tool}

The present invention relates to a cutting tool capable of cooling a cutting insert during cutting.

In general, a cutting insert is fastened to a cutting tool mounted on a machine tool and is used to cut a workpiece made of iron, non-ferrous metal, and non-metallic material.

2. Description of the Related Art With the recent development of aerospace and aviation technologies, the use of workpieces that are durable even in extreme environments has increased significantly. As a representative work piece, expensive work pieces such as Inconel and titanium are mainly used, and the use is expected to increase further in the future. Inconel, titanium is called a difficult-to-cut material, and unlike ordinary steel, cast iron, and stainless steel, there is a problem of lowering the life of the cutting insert by causing high temperature and welding problems during cutting. In order to solve this problem, a high-pressure coolant device is used that eliminates welding problems through cooling effect and chip removal.

In this regard, the cutting tool 1 disclosed in EP 3 167 984 A1 includes a holder body 2, a cutting insert 5, and a nozzle 10, as shown in FIGS. 12 to 14. . For reference, FIGS. 12, 13, and 14 correspond to FIGS. 1A, 1B, and 1C of the European Patent Publication, respectively, and for convenience of description, reference numerals used in the European Patent Publication are modified. It has been used as such, and these reference numbers do not refer to the same components even if they overlap with the reference numbers used in the description of the present invention described below.

The nozzle 10 has a single through hole 11 for fastening bolts, and also has a front end 13 and a rear end 14 and a bottom surface 15. And at least one coolant channel 17 is formed in the nozzle and extends from the first opening 18 to the second opening 19. And the first opening 18 is connected to the coolant supply pipe at the holder body 2 and the second opening 19 of the front end 13 functions as an outlet of the coolant. And at least one coolant channel 17 and the first opening 18 are spaced apart from the through hole 11.

However, the nozzle of such a conventional cutting tool is sprayed close to the cutting insert, but as soon as the coolant comes out of the spout, it is diffused immediately and there is a problem that it cannot accurately hit the spot.

In addition, when the fastening bolt for fixing the cutting insert cooling device to the tool holder becomes loose during high-speed machining, the nozzle 10 can move relative to the holder body 2, so that the coolant injection point for the cutting insert is easily displaced. This can cause serious problems with cooling performance.

An object of the present invention is to provide a cutting tool capable of preventing the diffusion of coolant, increasing the amount of coolant between the cutting insert and the workpiece, and rapidly adjusting the coolant speed to a desired spot.

In addition, it is an object of the present invention to provide a cutting tool capable of maintaining a coolant jetting point in the cutting insert by maximally suppressing the relative movement of the coolant injection part from the tool body even if the fastening bolt is loosened during high-speed machining.

In order to achieve the above object, the cutting tool according to the embodiment of the present invention, a tool body to which a cutting insert is mounted, and a coolant toward a cutting center of the cutting insert, and the tool by a fastening bolt A cutting tool having a coolant injection portion fixed to a body, wherein the coolant injection portion includes a coolant inlet formed on a lower surface, a coolant outlet formed at a front end, and a coolant connecting the coolant inlet and the coolant outlet to each other. Includes a runt channel, the coolant channel is a first curve section from the coolant inlet to the coolant outlet, a first straight section connected to the first curved section, a second curved section connected to the first straight section, A second straight section extending from the second curved section is provided, and the coolant channel gradually decreases in cross-sectional area from the coolant inlet toward the coolant outlet and then widens again, and the coolant inlet is circular and cool The runt outlet is characterized in that the transverse direction has an elliptical shape longer than the longitudinal direction.

In addition, the coolant injection portion further includes a fastening bolt support portion through which the fastening bolt is penetrated, supports the fastening bolt, and one side is open, and a fastening hole protruding from a lower surface, wherein the fastening bolt support portion has a head It is characterized in that it has a head seating portion in contact with a through hole through which the body portion of the fastening bolt passes.

In addition, when the head seating portion and the through hole are viewed from the front, the coolant injection portion is inclined at a predetermined angle from left to right, and the fastening bolt is also mounted on the tool body to be inclined at the predetermined angle. It is characterized by being.

In addition, the tool body includes a fastening groove in which the fastener of the coolant injection portion is slidingly coupled, and one end of the fastening groove has a center of the coolant discharge port when the coolant injection portion is fixed to the tool body. It is characterized in that it is located toward the center of the insert.

In addition, the fastener is characterized in that it is formed in a wedge shape with a wider width away from the lower surface of the coolant injection portion.

Further, the fastening groove includes a first partial groove extending from the other end and having a shape corresponding to the wedge shape of the fastener, and a second partial groove extending from the one end, and the width of the second partial groove It is characterized in that it is formed equal to or greater than the width of the fastener.

In addition, a coolant supply port is formed on the tool body, the coolant supply port is connected to the coolant inlet of the coolant injection part, and the coolant channel is aligned with the center of the cutting insert. .

In addition, when the coolant injection portion moves to the left, it is characterized in that the movement of the coolant injection portion is suppressed by engaging the head seating portion of the fastening bolt support portion on the bottom surface of the head of the fastening bolt.

As described above, the cutting insert cooling apparatus according to the embodiment of the present invention may have the following effects.

In this cutting tool, the coolant channel (flow path) is composed of four stages, and the cross-sectional area of the coolant channel is gradually reduced (the effect of increasing the speed of the coolant), and the cross-sectional area is increased again (the effect of increasing the discharge amount of the coolant) ), the cooling effect can be maximized by ejecting the coolant toward the cutting center of the cutting insert through the elliptical coolant outlet.

In addition, since the fastening bolt is mounted on the tool body to be inclined, even if the fastening bolt is loosened from the tool body somewhat due to vibration during high-speed cutting, the coolant spray spot is cut by preventing the coolant jet from moving to the left It can effectively prevent you from escaping.

In addition, the present invention also includes other effects that can be derived from the configuration of the present invention.

1 shows a cutting tool according to an embodiment of the present invention.
2 (a) is a view showing the coolant channel of the coolant injection part of the cutting tool of FIG. 1 from the side, and FIG. 2 (b) is a view showing the coolant channel of the coolant injection part of the cutting tool from the top. .
FIG. 3 is a view showing the coolant injection unit mounted on the tool body in the cutting tool of FIG. 1 from the front of the coolant injection unit.
4 is an experimental data and schematic diagram showing the effect of the coolant injection unit of the cutting tool of FIG. 1.
5 is a perspective view of the coolant injection unit of the cutting tool of FIG. 1.
Figure 6 is an exploded view of the main components of the cutting tool of Figure 1;
7 is a view showing a state in which the coolant injection unit slides on the tool body in the cutting tool of FIG. 1.
8 is a schematic view showing a state in which the coolant injection portion moves to the left and the head seating portion of the fastening bolt support portion is caught on the bottom surface of the head of the fastening bolt to suppress the movement of the coolant injection portion.
9 is a perspective view of the coolant injection portion of the cutting tool of FIG. 1 as viewed from the bottom.
Figure 10 is a photograph showing a coolant injection unit of the present invention showing a state of concentration and injection compared to a large flow rate than the prior art.
11 is a photograph of a chip state showing a state in which the chip processing performance of the present invention is significantly improved.
12 shows a state in which the coolant channel of the cutting tool of FIG. 1 is gradually reduced and expanded.
13 to 15 are views of a conventional cutting tool.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

As shown in FIG. 1, the cutting tool 100 according to an embodiment of the present invention includes a tool body 1 on which the cutting insert 200 is mounted and a cutting center 200 of the cutting insert 200 It includes a coolant injection part (2) fixed to the tool body (1) by spraying a coolant (cutting fluid) toward 201) and fastening bolts (3).

2, the coolant injection unit 2 includes a coolant inlet 21 formed on a lower surface, a coolant outlet 22 formed on the front surface, a coolant inlet 21 and a coolant outlet ( 22) a coolant channel 23 connecting each other.

In particular, the coolant channel 23 includes a first curved section 231 from the coolant inlet 21 to the coolant outlet 22 and a first straight section 232 connected to the first curved section 231. And, a second curved section 233 connected to the first straight section 232 and a second straight section 234 connected to the second curved section 233 in sequence. That is, after the coolant flows into the coolant inlet 21, it passes through the four-step section, that is, the curved section 231 → the straight section 232 → the curved section 233 → the straight section 234, and finally It is discharged from the coolant outlet 22.

2 and 3, the coolant inlet 21 is formed in a circular shape, and the coolant outlet 22 is formed in an elliptical shape. Specifically, the coolant outlet 22 has a transverse width to cover a predetermined section L of the cutting center 200 of the cutting insert 200 while having an elliptical shape in which the transverse direction is longer than the longitudinal direction ( See Figure 8).

In addition, the coolant channel 23 has a smaller cross-sectional area in the process from the coolant inlet 21 to the coolant outlet 22, and then increases again. Through this, the injection speed can be increased and the amount discharged from the coolant outlet can be increased. That is, as shown in (a) of FIG. 2, the cross-sectional area gradually decreases to the intermediate point A of the second curved section 233, and the cross-sectional area gradually increases as it passes through the intermediate point A. Can be. 12, the coolant channel 23 is gradually reduced and expanded as described above.

As described above, in this cutting tool 100, the coolant channel 23 (flow path) is composed of four stages, and the cross-sectional area of the coolant channel 23 is gradually reduced (the effect of increasing the speed of the coolant) again. The cooling effect can be maximized by increasing the cross-sectional area (the effect of increasing the discharge amount of the coolant) and ejecting the coolant toward the cutting center 101 of the cutting insert through the elliptical coolant discharge port 22.

4 has a coolant channel composed of only a straight section and a coolant ejection unit (left side in FIG. 4) having a coolant discharge port in a circular shape, and a coolant injection unit (right side in FIG. 4) according to the present invention. As a result of the comparative experiment, it can be seen that the coolant speed, the coolant amount, and the vortex are significantly improved in the coolant injection unit of the present invention.

In addition, as shown in FIG. 5, the coolant injection part 2 is provided with a fastening bolt 3 through which the fastening bolt 3 is penetrated, supports the fastening bolt 3, and an open fastening bolt support 24 with one side open, protruding from the lower surface. The fastener 25 is further included. By using the fastening bolt support portion 24 with one side open, the coolant injection portion 2 can be easily sliding-coupled or disengaged to the tool body 1 (see FIG. 6).

And, as shown in Figure 6, the tool body 1 includes a fastening groove 11 to which the fastener 25 of the coolant injection part 2 is slidingly coupled. The fastening groove 11 may be formed to be elongated in a direction perpendicular to the direction in which the coolant is injected, and the fastener 25 of the coolant injection unit 2 to be described later from the other end 112 of the fastening groove 11 In the shape corresponding to the wedge-shaped first partial groove 113 is extended. Therefore, when the fasteners 25 of the coolant injection portion 2 are located in the first partial groove 113, they are wedge-coupled with each other so that the coolant injection portion 2 does not deviate from the tool body 1. Meanwhile, unlike the first partial groove 113, the second partial groove 114 extending from one end 111 of the fastening groove 11 has a substantially rectangular cross-section and a width of the fastener 25 It is formed equal to or larger than the width w of (see FIG. 2(b) ). In addition, the width of the second partial groove 114 is formed larger than the first partial groove 113. The boundary between the first partial groove 113 and the second partial groove 114 may be located in the middle of the fastening groove 11.

When mounting the coolant injection portion (2) to the tool body (1), the fastener (25) of the coolant injection portion (2) in the second partial groove (114) of the tool body (1) is formed wider width After positioning, the fastener 25 is brought into contact with one end 111 of the fastening groove 11, and then fixed with a fastening bolt 3. When replacing the cutting insert 200, the coolant injection portion 2 is loosened only the fastening bolt 3 to the extent that it can slide along the fastening groove 11, and then, as shown in Figure 7, coolant powder It is enough to slide the thread part 2 in a direction away from the one end 111 of the fastening groove 11. At this time, the fastener 25 is wedge-connected to the first partial groove 113 of the fastening groove 11, so that the coolant injection part 2 does not deviate from the tool body 1 even if the operator does not hold it separately. Due to this, the operator can easily replace the cutting insert. On the other hand, the length of the first partial groove 113 and the length (ℓ) of the fastener 25 (refer to (b) of FIG. 2), as shown in FIG. 7, the coolant injection part 2 is connected to the fastening groove ( When sliding in a direction away from one side end 111 of 11), the cutting insert 200 is set to a size that does not cover, so that the cutting insert 200 can be replaced.

As shown in FIG. 5, the fastener 25 of the coolant injection part 2 increases in width as it moves away from the lower surface of the coolant injection part 2, and the fastening groove 11 of the tool body 1 By being formed corresponding thereto, when the coolant injection portion 2 is slidingly coupled to the tool body 1, the fastener 24 and the fastening groove 11 are wedge-coupled to each other to coolant injection portion 2 It can be stably coupled to the tool body (1). The inner angle α of one side of the fastener 25 may be formed at 30 to 90°.

On the other hand, referring to Figure 7, one side end 111 of the fastening groove 11, when the coolant injection portion 2 is fixed to the tool body (1), the center of the coolant outlet 22 (C / L ) Is positioned to face the cutting center 101 of the cutting insert 100.

As shown in FIG. 5, the fastening bolt support part 24 has a head seating part 241 in contact with the head 31 of the fastening bolt 3 and a body part 32 of the fastening bolt 3 through It is provided with a through hole 242 to engage.

However, referring to FIG. 8, when the head seating portion 241 and the through hole 242 are viewed from the front, the coolant injection portion 2 is inclined at a predetermined angle from the upper left to the lower right. Further, accordingly, the fastening bolt 3 is also mounted on the tool body 1 to be inclined at the same angle. Here, the inclined angle may be, for example, 5°. Through this, even if the fastening bolt 3 is loosened and loosened from the tool body 1 somewhat due to vibration during high-speed cutting, it is possible to suppress the coolant injection part 2 from moving to the left.

That is, when the fastening bolt 3 is loose, the bottom surface of the head 31 of the fastening bolt 3 is not in close contact with the head seating portion 241 of the fastening bolt support 24, and in this case, it is cool due to processing vibration. The runt injection unit 2 may move slowly to the left (see FIG. 8). For reference, since the fastener 25 of the coolant injection unit 2 is supported by one end 111 of the fastening groove 11, the coolant injection unit 2 does not move to the right.

However, in the present invention, by mounting the fastening bolt 3 at a predetermined angle, when the coolant injection portion 2 moves to the left, the head seating portion of the fastening bolt support portion 24 on the bottom surface of the fastening bolt head 31 When (241) is applied, an effect of suppressing movement can be obtained.

For reference, as shown in FIG. 8, since the greatest amount of heat is generated at the portion of the cutting center 100 of the cutting insert 100 during cutting, a coolant is provided so as to cover a predetermined section L around it. Spraying is very important to improve the life of the cutting insert. In the present invention, the lateral width of the coolant outlet 22 is formed in correspondence with a predetermined section (L). On the other hand, this predetermined section (L) may be appropriately set in consideration of the material of the individual cutting insert, the properties of the workpiece, and the like.

Meanwhile, referring to FIGS. 3, 6, and 8, in the cutting tool 100, a coolant supply port 12 is formed on the tool body 1, and the coolant supply port 12 is a coolant injection unit. Following the coolant inlet 21 formed on the bottom surface of (2), the coolant channel 23 is aligned with the cutting center 100 of the cutting insert 100 to align the cutting center 200 with the cutting center 200 By allowing the coolant to be accurately ejected at 201), the life of the cutting insert can be significantly increased. Therefore, when machining a difficult-to-cut material, it takes a lot of time to replace the cutting insert due to a decrease in the life of the cutting insert, and also considering a situation in which the cutting insert replacement cost is high, the coolant speed and By increasing the amount and intensively spraying coolant at the correct position (dot), it is possible to efficiently cool the cutting insert, thereby achieving excellent processing cost savings. In FIG. 10, the conventional cutting tool has a small coolant injection amount and is also sprayed while being dispersed, while the cutting tool of the present invention shows a state in which a large amount of coolant is concentrated and sprayed. The chip processing performance shows a marked improvement in the cutting tool of the present invention.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

100...cutting tool
1...tool body,
2... coolant spray
21...coolant inlet, 22...coolant outlet
23...Coolant channel
231...first curve section, 232...first straight section
233...second curve section, 234...second straight section
24 ... fastening bolt support
241...head seat, 242...through hole
25... fastener
3...fastening bolt, 31...fastening bolt head
200... cutting insert

Claims (8)

A cutting tool having a tool body on which a cutting insert is mounted, and a coolant injection part fixed to the tool body by means of a fastening bolt and spraying a coolant toward the cutting center of the cutting insert,
The coolant injection unit,
Coolant inlet formed on the lower surface,
Coolant outlet formed on the front,
Coolant channel connecting the coolant inlet and the coolant outlet
It includes,
The coolant channel may include a first curve section from the coolant inlet to the coolant outlet, a first straight section connected to the first curved section, a second curved section connected to the first straight section, and the second curved section. It has a second continuous straight section,
The coolant channel has a smaller cross-sectional area as it goes from the coolant inlet to the coolant outlet, and then widens again.
The coolant inlet is circular,
The coolant outlet has an elliptical shape in which the transverse direction is longer than the longitudinal direction.
Cutting tool. In claim 1,
The coolant injection unit
A fastening bolt support portion through which the fastening bolt is penetrated, supports the fastening bolt, and has one side open;
Fastener protruding from the bottom
Further comprising,
The fastening bolt support
A head seating portion in contact with the head of the fastening bolt,
The through hole through which the body portion of the fastening bolt passes
Equipped with
Cutting tool. In claim 2,
The head seating portion and the through hole are inclined at a predetermined angle from the upper left to the lower right when looking at the coolant injection portion from the front,
The fastening bolt is also mounted to the tool body to be inclined at the predetermined angle.
Cutting tool. In claim 3,
The tool body includes a fastening groove to which the fastener of the coolant injection part is slidingly coupled,
One side end of the fastening groove is when the coolant injection portion is fixed to the tool body, the center of the coolant outlet is located toward the center of the insert
Cutting tool. In claim 4,
The fastener is a cutting tool formed in a wedge shape that increases in width as it moves away from the lower surface of the coolant injection portion. In claim 5,
The fastening groove
A first partial groove extending from the other end and having a shape corresponding to the wedge shape of the fastener;
A second partial groove extending from the one end
It includes,
The width of the second partial groove is formed equal to or greater than the width of the fastener.
Cutting tool. In claim 6,
A coolant supply port is formed on the tool body, and the coolant supply port is connected to the coolant inlet of the coolant injection part,
The coolant channel is aligned with the center of the cutting insert.
Cutting tool. In claim 3,
Cutting tool to suppress the movement of the coolant injection portion by engaging the head seating portion of the fastening bolt support portion on the bottom surface of the head of the fastening bolt when the coolant injection portion moves to the left.

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