Cutting insert and cutting edge replaceable cutting tool

Abstract

To provide an L-shape cutting insert that is configured so that a coolant can be properly supplied to a cutting edge thereof.SOLUTION: A cutting insert, which is used while being held on an upper jaw part and a lower jaw part of a holder of a cutting edge replaceable cutting tool, comprises a rod-like body part extended in a first direction and a rod-like cutting blade part connected to the body part through a bent part and extended in a second direction different from the first direction. When viewed from a third direction that is orthogonal to both of the first direction and the second direction, a surface at one side of the cutting insert is a lower surface supported by the lower jaw part and a surface at the opposite side of the lower surface is an upper surface held by the upper jaw part. The upper surface is provided with a cutting blade positioned at a tip part at the opposite side of the bent part of the cutting blade part and a wall part positioned at an outer periphery part of the bent part and partially protruded upward on the upper surface. An inner side surface pointing to an inner periphery side of the bent part of a side surface of the wall part has a curved surface shape extending along a bending direction of the cutting insert.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a cutting insert and an indexable cutting tool.

Background Art

[0002] Conventionally, a cutting tool for inner diameter grooving provided with an L-shaped cutting insert has been known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a cutting tool provided with an L-shaped cutting insert, the cutting insert is bent in a direction orthogonal to the extending direction of the holder. Therefore, when a coolant discharge port is provided in the holder, the cutting edge direction of the cutting insert and the coolant discharge direction do not match. As a result, it is difficult to apply the coolant at an appropriate angle, and there has been a problem that cutting heat easily increases.

[0005] One object of the present invention is to provide an L-shaped cutting insert capable of appropriately supplying coolant to the cutting edge, and an indexable cutting tool provided with the same.

Means for Solving the Problems

[0006] According to one aspect of the present invention, there is provided a cutting insert that is held and used in the upper jaw portion and the lower jaw portion of a holder of a cutting tool with replaceable cutting edges, the cutting insert comprising: a rod-shaped main body portion extending in a first direction; and a rod-shaped cutting edge portion connected to the main body portion via a bent portion and extending in a second direction different from the first direction. One side surface of the cutting insert as viewed from a third direction orthogonal to both the first direction and the second direction is a lower surface supported by the lower jaw portion, and the surface opposite to the lower surface is an upper surface supported by the upper jaw portion. The upper surface has a cutting edge located at the tip portion of the cutting edge portion on the side opposite to the bent portion, and a wall portion located at the outer peripheral portion of the bent portion and partially protruding upward on the upper surface. The inner side surface of the side surface of the wall portion facing the inner peripheral side of the bent portion has a curved surface shape extending along the bending direction of the cutting insert.

[0007] According to this configuration, by applying the coolant discharged from the coolant discharge port of the holder to the wall portion, the traveling direction of the coolant can be changed from the direction along the main body portion to the direction along the cutting edge portion. Thereby, the coolant can be supplied to the cutting edge located at the tip of the cutting edge portion from the length direction of the cutting edge portion. Since the coolant can be supplied to the cutting edge at an appropriate angle, the cooling efficiency of the cutting edge can be increased and the rise of cutting heat can be suppressed.

[0008] The upper surface may have a concave groove extending from the main body portion to the cutting edge portion via the bent portion, and in the bent portion, the concave groove may be located on the inner peripheral side of the bent portion with respect to the wall portion.

[0009] The concave groove may be configured to curve along the inner side surface of the wall portion as viewed from above.

[0010] According to one aspect of the present invention, there is provided a cutting tool with replaceable cutting edges, comprising the above cutting insert and a holder having an upper jaw portion and a lower jaw portion for holding the cutting insert, wherein the holder has a coolant discharge port for discharging coolant toward the wall portion of the cutting insert.

Advantages of the Invention

[0011] According to one aspect of the present invention, there are provided an L-shaped cutting insert capable of appropriately supplying a coolant to a cutting edge, and an exchangeable cutting tool having the same.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0013] FIG. 1 is a partial perspective view of an exchangeable cutting tool according to an embodiment. FIG. 2 is a perspective view of a cutting insert according to an embodiment. FIG. 3 is a plan view of a cutting insert according to an embodiment. FIG. 4 is a side view of a cutting insert according to an embodiment as viewed from the direction (second direction d2) in which the cutting edge portion extends. FIG. 5 is a plan view of a cutting insert according to an embodiment as viewed from the direction (first direction d1) in which the main body portion extends. A third direction orthogonal to both the first direction d1 and the second direction d2 is the vertical direction in FIG. 1.

[0014] The cutting tool 100 with replaceable cutting edges shown in Fig. 1 has a holder 1 and a cutting insert 10. The holder 1 includes a rod-shaped holder body 2 and a modular blade 3 fixed to the tip of the holder body 2. The holder body 2 and the modular blade 3 are made of, for example, steel. In this embodiment, in the longitudinal direction of the holder 1, the side where the cutting insert 10 is attached is referred to as the tip side, and the base end side of the holder body 2 on the side opposite to the cutting insert 10 is referred to as the rear end side. Also, the vertical direction in the following description refers to the vertical direction in Fig. 1. In this embodiment, as the holder 1, a configuration in which the modular blade 3 and the holder body 2 are separate bodies is illustrated, but it is not limited to this configuration. The holder 1 may have a configuration in which the modular blade 3 and the holder body 2 are integrated.

[0015] The holder body 2 has a square prism-shaped shank portion 2a and a blade mounting portion 2b located at the tip of the shank portion 2a. The blade mounting portion 2b has screw holes on its upper surface, tip surface, and side surfaces. The modular blade 3 is fixed to the blade mounting portion 2b by screws tightened into the screw holes of the blade mounting portion 2b.

[0016] The modular blade 3 has a slit 3a extending from the tip of the modular blade 3 toward the rear end portion 3A side. Among the modular blade 3, the portion above the slit 3a is the upper jaw portion 3b, and the portion below the slit 3a is the lower jaw portion 3c. The shank portion of the holder 1 is connected behind the lower jaw portion 3c of the modular blade 3. The connecting portion 3d between the upper jaw portion 3b and the lower jaw portion 3c is thin, and the upper jaw portion 3b can be deformed so as to bend toward the lower jaw portion 3c side with the connecting portion 3d as a fulcrum.

[0017] The lower jaw portion 3c has a pedestal portion 4 at the tip of the lower jaw portion 3c. A pedestal surface 5 formed of a flat surface having a rectangular shape in plan view is formed on the upper surface of the pedestal portion 4. The pedestal surface 5 extends from the tip of the lower jaw portion 3c to the middle of the slit 3a in the longitudinal direction of the modular blade 3.

[0018] The upper jaw part 3b has a pressing part 6 at the tip of the upper jaw part 3b. The pressing part 6 is in the shape of a triangular plate in side view that tapers towards the tip side. The tip of the pressing part 6 is located on the rear end side with respect to the tip of the lower jaw part 3c. A pressing surface 7 is formed on the surface of the pressing part 6 facing the pedestal part 4 side. The pressing surface 7 extends from the tip of the upper jaw part 3b to the middle of the slit 3a.

[0019] The upper jaw part 3b has a coolant discharge port 9 that opens towards the tip side on the upper surface of the tip of the pressing part 6. The coolant discharge port 9 is connected to a coolant flow path formed inside the modular blade 3. The other end of the coolant flow path is connected to a coolant supply port (not shown). Coolant is supplied to the modular blade 3 through the coolant supply port, and the supplied coolant is discharged from the coolant discharge port 9 in the tip direction of the modular blade 3 via the internal coolant flow path.

[0020] In the holder 1, the pedestal surface 5 of the pedestal part 4 and the pressing surface 7 of the pressing part 6 are arranged to face each other in the vertical direction. In the holder 1, the pedestal part 4 and the pressing part 6 constitute an insert mounting seat 8.

[0021] A clamp part 3e is provided on the upper part of the modular blade 3. The clamp part 3e constitutes a part of the clamping means of the insert mounting seat 8 of the holder 1. The clamp part 3e constitutes the seat surface of a clamp screw (not shown) that is tightened into the holder 1. By pushing the clamp part 3e downward with the clamp screw, the cutting insert 10 inserted between the upper jaw part 3b and the lower jaw part 3c can be fixed.

[0022] The cutting insert 10 is clamped and fixed in the vertical direction by the pedestal part 4 and the pressing part 6 of the insert mounting seat 8. The cutting insert 10 is made of, for example, cemented carbide. As shown in FIGS. 2 and 3, the cutting insert 10 is a cutting insert having a shape bent in an L shape in plan view. The cutting insert 10 includes a bent portion 13, a rod-shaped main body portion 12 extending along a first direction d1 with the bent portion 13 as a base point, and a rod-shaped cutting edge portion 16 extending along a second direction d2 orthogonal to the first direction d1 with the bent portion 13 as a base point. In the present embodiment, the main body portion 12, the bent portion 13, and the cutting edge portion 16 are parts of the single-member cutting insert 10. In the present embodiment, the direction from the bent portion 13 toward the main body portion 12 is defined as the positive side of the first direction d1, and the direction from the bent portion 13 toward the cutting edge portion 16 is defined as the positive side of the second direction d2.

[0023] The cutting insert 10 has an L shape bent at 90° at the bent portion 13. The bending angle of the cutting insert 10 is not limited to 90°, and can be any angle of 1° or more and 90° or less.

[0024] As shown in FIG. 4, the upper surface of the cutting insert 10 is a pressed surface 14 facing the pressing surface 7 of the pressing portion 6. In the case of the present embodiment, the upper surface of the main body portion 12 is the pressed surface 14. The lower surface of the cutting insert 10 is a seating surface 15 facing the pedestal surface 5 of the pedestal portion 4. In the case of the present embodiment, the lower surface of the main body portion 12 and a part of the lower surface of the bent portion 13 constitute the seating surface 15.

[0025] The cutting edge portion 16 extends along the second direction d2 orthogonal to the main body portion 12. Cutting edges 17 are formed on three sides of the upper surface end portion of the cutting edge portion 16. The cutting edges 17 are formed on a side extending substantially parallel to the longitudinal direction (first direction d1) of the main body portion 12 and two sides adjacent to this side and extending along the extending direction (second direction d2) of the cutting edge portion 16 at the tip portion of the upper surface of the cutting edge portion 16. The side surface of the cutting edge portion 16 continuous with the cutting edge 17 is a relief surface 18 of the cutting edge 17. The upper surface portion of the cutting edge portion 16 continuous with the cutting edge 17 is a rake surface 19. In the present embodiment, the rake surface 19 has a trapezoidal shape that widens toward the tip of the cutting edge portion 16 in plan view.

[0026] From the end of the scraping surface 19 on the main body portion 12 side toward the bent portion 13, a concave groove 11 having a substantially V-shaped cross section extends. The concave groove 11 extends from the upper surface of the cutting edge portion 16, passes through the upper surface of the bent portion 13, and reaches the upper surface of the main body portion 12, reaching the end portion of the main body portion 12 on the side opposite to the bent portion 13. The concave groove 11 extends linearly along the second direction d2 on the cutting edge portion 16. The concave groove 11 bends in an arc shape on the bent portion 13 and changes its direction toward the first direction d1. The concave groove 11 extends linearly along the first direction d1 on the main body portion 12.

[0027] FIG. 6 is a cross-sectional view of the cutting insert 10 taken along line VI-VI of FIG. 3. FIG. 7 is a cross-sectional view of the cutting insert 10 taken along line VII-VII of FIG. 3. As shown in FIGS. 6 and 7, the concave groove 11 is formed in a V shape by a pair of inclined surfaces 11a and 11b that are separated from each other as they go upward in a vertical cross section along the first direction d1. In the case of this embodiment, as shown in FIG. 4, the height position of the upper end of the concave groove 11 substantially coincides with the height position of the pressed surface 14. The height position of the scraping surface 19 is lower than the height position of the upper end of the concave groove 11. The height position of the scraping surface 19 substantially coincides with the height position of the bottom of the concave groove 11. An inclined surface 16a (see FIGS. 2 and 3) that descends from the upper end of the concave groove 11 toward the scraping surface 19 is formed between the region where the concave groove 11 is formed and the scraping surface 19.

[0028] The cutting insert 10 of this embodiment has a bottom groove 11c located between the inclined surfaces 11a and 11b at the bottom of the concave groove 11. The bottom groove 11c is a groove portion that is cut deeper than the concave groove 11. The bottom groove 11c is located at the center in the width direction of the concave groove 11 and extends along the concave groove 11.

[0029] The bottom groove 11c of the concave groove 11 protrudes toward the rake face 19 from the end on the rake face 19 side (the end on the tip side in the second direction d2) of the cutting edge portion 16 on the upper surface of the cutting edge portion 16. The bottom groove 11c extends from the cutting edge portion 16 over the bent portion 13 to the main body portion 12. The bottom groove 11c extends on the main body portion 12 by a length of about 1 / 4 of the main body portion 12 from the end on the bent portion 13 side. The bottom groove 11c is not formed in the region of the upper surface of the main body portion 12 that is located on the side opposite to the bent portion 13. That is, the bottom groove 11c is not formed in the pressed surface 14 that faces the upper jaw portion 3b of the holder 1.

[0030] As shown in FIGS. 5 to 7, a concave groove 21 extending linearly from the end on the negative side in the first direction d1 of the bent portion 13 to the end on the positive side in the first direction d1 of the main body portion 12 is provided on the seating surface 15 provided on the lower surface of the cutting insert 10. The concave groove 21 is formed in the same shape as the concave groove 11 formed in the pressed surface 14 of the main body portion 12. No bottom groove is formed at the bottom of the concave groove 21. The concave groove 21 has an inclined surface 21a and an inclined surface 21b.

[0031] The cutting insert 10 is attached to the insert mounting seat 8 by inserting the main body portion 12. With the seating surface 15 of the cutting insert 10 supported from below by the pedestal surface 5 of the insert mounting seat 8, when the clamp screw is tightened, the pressing surface 7 of the pressing portion 6 is pressed against the pressed surface 14 of the cutting insert 10. Thereby, the cutting insert 10 is fixed in a state of being sandwiched by the upper jaw portion 3b and the lower jaw portion 3c.

[0032] FIG. 8 is a cross-sectional view showing the clamped state of the cutting insert 10 by the holder 1. As shown in FIG. 8, a support protrusion 5a protruding toward the upper jaw portion 3b is provided on the pedestal surface 5 of the lower jaw portion 3c. The support protrusion 5a is a linear protrusion extending along the direction in which the pedestal surface 5 extends. The support protrusion 5a is a protrusion having a convex V-shaped cross section with the center in the width direction of the pedestal surface 5 bulging upward in the drawing. Further, a pressing projection 7a that protrudes toward the lower jaw portion 3c is provided on the pressing surface 7 of the upper jaw portion 3b. The pressing projection 7a is a linear projection that extends along the direction in which the pressing surface 7 extends. The pressing projection 7a is a projection with a convex V-shaped cross section where the central portion in the width direction of the pressing surface 7 bulges downward as shown in the figure.

[0033] As shown in FIG. 8, in a state where the cutting insert 10 is sandwiched between the upper jaw portion 3b and the lower jaw portion 3c, the support projection 5a on the pedestal surface 5 fits into the concave groove 21 on the lower surface of the cutting insert 10. Further, the pressing projection 7a on the pressing surface 7 fits into the concave groove 11 on the upper surface of the cutting insert 10. According to this clamping mechanism, the cutting insert 10 is firmly fixed by the fitting structure of the above-mentioned projections and concave grooves. Thereby, even when a force is applied in the width direction of the cutting insert 10 (the horizontal direction orthogonal to the direction in which the main body portion 12 extends), it is possible to suppress the cutting insert 10 from shifting from the clamping position. It is possible to suppress a decrease in machining accuracy due to displacement of the cutting insert 10, and it is also possible to suppress breakage or detachment of the cutting insert 10.

[0034] As shown in FIGS. 2 to 5, a wall portion 25 located on the outer peripheral portion of the bent portion 13 is formed on the upper surface of the cutting insert 10. The wall portion 25 partially protrudes upward on the upper surface of the cutting insert 10. As shown in FIG. 3, the wall portion 25 is located at the outer corner of the concave groove 11 at the position where the cutting insert 10 bends.

[0035] The wall portion 25 has three side surfaces facing a direction orthogonal to the vertical direction. Specifically, as shown in FIG. 3, the wall portion 25 has an inner side surface 25a facing the inner peripheral side of the bent portion 13, an outer side surface 25b facing the negative side of the first direction d1, and an outer side surface 25c facing the negative side of the second direction d2.

[0036] The inner surface 25a extends along the outer peripheral edge of the concave groove 11 in the bent portion 13 in a plan view. The inner surface 25a has a curved surface shape extending along the bending direction of the cutting insert 10. In the case of this embodiment, the inner surface 25a is an arcuate cylindrical surface in a plan view. The shape of the inner surface 25a is not limited to a cylindrical surface, and may be a curved surface shape other than a cylindrical surface. The inner surface 25a is a surface generally along the first direction d1 at the end on the main body portion 12 side, and is a surface generally along the second direction d2 at the end on the cutting edge portion 16 side. That is, the inner surface 25a is a curved surface shape that gradually changes from the first direction d1 to the second direction d2.

[0037] The outer surfaces 25b and 25c are flat surfaces constituting the outer surface of the bent portion 13. Also, the upper surface of the wall portion 25 is a flat surface extending in a direction orthogonal to the vertical direction.

[0038] As shown in FIG. 1, when the cutting insert 10 having the above configuration is attached to the holder 1, the wall portion 25 of the cutting insert 10 is disposed in front of the coolant discharge port 9 of the modular blade 3. When the tip-exchangeable cutting tool 100 is used, coolant is discharged from the coolant discharge port 9 toward the tip side of the modular blade 3. The discharged coolant flies along the direction (the first direction d1) in which the main body portion 12 of the cutting insert 10 extends and collides with the inner surface 25a of the wall portion 25. Then, since the inner surface 25a has a curved surface shape extending along the bent shape of the cutting insert 10, the traveling direction of the coolant is bent along the inner surface 25a and directed toward the cutting edge portion 16 side. The coolant whose traveling direction has been bent flies along the direction (the second direction d2) in which the cutting edge 16 extends from the inner surface 25a and is supplied to the cutting edge 17 at the tip of the cutting edge portion 16 from the rake face 19 side.

[0039] According to the cutting tool 100 with replaceable cutting edges of the present embodiment, by providing the cutting insert 10 having the wall portion 25 in the bent portion 13, the coolant discharged from the coolant discharge port 9 can be supplied to the cutting edge 17 at an appropriate angle. Thereby, since the ratio of the coolant that effectively acts on the cooling of the cutting insert 10 can be increased, the temperature rise of the cutting insert 10 can be suppressed.

[0040] In the present embodiment, the upward protruding height of the wall portion 25 is preferably adjusted according to the discharge direction of the coolant discharged from the coolant discharge port 9, the scattering state of the coolant, the positional relationship between the coolant discharge port 9 and the wall portion 25, and the like.

[0041] Further, in the cutting insert 10 of the present embodiment, a concave groove 11 extending from the main body portion 12 to the cutting edge portion 16 via the bent portion 13 is provided on the upper surface of the cutting insert 10. In the bent portion 13, the concave groove 11 is located on the inner peripheral side of the bent portion 13 rather than the wall portion 25. According to this configuration, the coolant discharged from the coolant discharge port 9 can be guided to the cutting edge 17 along the concave groove 11. Thereby, the ratio of the coolant contributing to the cooling around the cutting edge 17 can be increased, and the cooling efficiency can be improved.

[0042] Furthermore, in the present embodiment, the concave groove 11 is curved along the inner surface 25a of the wall portion 25 when viewed from above. According to this configuration, the concave groove 11 can smoothly guide the coolant toward the cutting edge portion 16.

[0043] Furthermore, in the present embodiment, a bottom groove 11c is provided at the bottom of the concave groove 11, and the bottom groove 11c extends to a position closer to the cutting edge 17 than the end of the concave groove 11. According to this configuration, since the coolant is held in the narrow bottom groove 11c, the coolant can be scooped up onto the rake face 19 through the bottom groove 11c. The coolant supplied from the rake face 19 to the cutting edge 17 can push the generated chips in a direction away from the rake face 19, and the chip dischargeability can be improved.

Description of Reference Numerals

[0044] 100... Tip-exchangeable cutting tool 10... Cutting insert 1... Holder 3... Modular blade 3a... Slit 3b... Upper jaw part 3c... Lower jaw part 3d... Connection part 3e... Clamp part 3A... Rear end part 4... Base part 5... Base surface 5a... Support protrusion 6... Pressing part 7... Pressing surface 7a... Pressing protrusion 8... Insert mounting seat 9... Coolant discharge port 11,21... Concave groove 11a,11b,21a,21b... Inclined surface 16a... Inclined surface 11c... Bottom groove 12... Body part 13... Bending part 14... Surface to be pressed 15... Seating surface 16... Cutting edge part 17... Cutting edge 18... Relief surface 19... Rake surface 25... Wall part 25a... Inner surface 25b,25c... Outer surface d1... First direction d2... Second direction

Claims

1. A cutting insert used while being held by an upper jaw portion and a lower jaw portion of a holder of a cutting tool with an exchangeable cutting edge, comprising: a rod-shaped main body portion extending in a first direction; and a rod-shaped cutting edge portion connected to the main body portion via a bent portion and extending in a second direction different from the first direction, wherein a lower surface on one side of the cutting insert as viewed from a third direction orthogonal to both the first direction and the second direction is supported by the lower jaw portion, and an upper surface on the side opposite to the lower surface is supported by the upper jaw portion, and on the upper surface, a cutting edge located at a tip portion of the cutting edge portion on the side opposite to the bent portion; and a wall portion located at an outer peripheral portion of the bent portion and partially protruding upward on the upper surface, are provided, wherein an inner surface of the side surface of the wall portion facing the inner peripheral side of the bent portion has a curved surface shape extending along the bending direction of the cutting insert. Cutting insert.

2. The upper surface has a concave groove extending from the main body portion, through the bent portion, to the cutting edge portion, and in the bent portion, the concave groove is located on the inner peripheral side of the bent portion with respect to the wall portion. The cutting insert according to claim 1.

3. The concave groove curves along the inner surface of the wall portion as viewed from above. The cutting insert according to claim 2.

4. A cutting tool with an exchangeable cutting edge, comprising the cutting insert according to any one of claims 1 to 3 and a holder having an upper jaw portion and a lower jaw portion for holding the cutting insert, wherein the holder has a coolant discharge port in the upper jaw portion for discharging coolant toward the wall portion of the cutting insert. Cutting tool with an exchangeable cutting edge.

Images