Tip replaceable cutting tool

Abstract

To provide a tip replaceable cutting tool as a cutting tool provided with a bent shape cutting insert, and capable of performing stable machining even for machining other than grooving.SOLUTION: A tip replaceable cutting tool includes: a holder provided with an insert attachment seat; and a cutting insert held on the insert attachment seat. The cutting insert includes a body part, and a cutting blade part extending in a direction intersecting with the body part from the tip end part of the body part. The top surface of the cutting insert on which a pressed surface is provided, has a recessed groove extending in a direction orthogonal to the direction where the body part extends. The holder includes an upper jaw part and a lower jaw part holding the cutting insert. The lower jaw part has a pedestal surface on the surface facing the upper jaw part. The upper jaw part includes on the surface facing the lower jaw part, a pressing surface, and a projection part projecting to the side of the lower jaw part and disposed in the recessed groove of the cutting insert.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an indexable cutting tool. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a cutting tool for internal grooving having an L-shaped cutting insert has been known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6346200 Summary of the Invention [Problem to be solved by the invention]

[0004] It is expected that cutting tools equipped with L-shaped cutting inserts will be used for profiling as well as groove cutting. The L-shaped cutting insert has a rod-shaped main body held by a holder and a cutting part extending from the tip of the main body in a direction perpendicular to the main body. When profiling is performed using an L-shaped cutting insert, a force acts on the cutting insert in a direction that pulls the cutting insert out of the holder, which may cause the clamping position of the cutting insert to shift.

[0005] An object of the present invention is to provide a cutting tool having an indexable cutting tip, which is equipped with a cutting insert having a curved shape and is capable of stable machining in machining applications other than grooving. [Means for solving the problem]

[0006] A cutting tool according to one aspect of the present invention is an indexable cutting tool including a holder having an insert mounting seat with a pressing surface and a seating surface facing each other, and a cutting insert held by the insert mounting seat and having a pressed surface and a seating surface that contact the pressing surface and the seating surface, respectively. The cutting insert has a rod-shaped main body portion and a cutting edge portion extending from a tip end of the main body portion in a direction intersecting with the main body portion in a plan view with the seating surface as a lower surface. The upper surface of the cutting insert on which the pressed surface is provided has a concave groove extending in a direction perpendicular to the extension direction of the main body portion. The holder includes an upper jaw portion and a lower jaw portion that grip the cutting insert. The lower jaw portion has the seating surface on a surface facing the upper jaw portion. The upper jaw portion has the pressing surface and a protrusion portion that protrudes toward the lower jaw portion and is disposed in the concave groove of the cutting insert on a surface facing the lower jaw portion.

[0007] According to the above configuration, a groove is formed on the upper surface of the cutting insert, and a protrusion is formed on the upper jaw of the insert mounting seat, so that when the cutting insert is mounted on the insert mounting seat, the protrusion is disposed in the groove of the cutting insert. As a result, even if a force acts on the cutting insert in a direction to pull the cutting insert out of the insert mounting seat during copying, for example, the protrusion disposed in the groove is caught on the wall surface of the groove. As a result, it is possible to prevent the clamping position of the cutting insert from shifting during processing. According to one aspect of the present invention, there is provided an indexable cutting tool capable of stable processing in processing applications other than grooving.

[0008] The protrusion may be a linear protrusion extending along a direction in which the recessed groove extends.

[0009] The cutting insert may have the groove on an upper surface of a portion where the cutting insert is bent.

[0010] The cutting insert may have the groove on its upper surface at a position away from a portion where the cutting insert bends. Effect of the Invention

[0011] According to one aspect of the present invention, there is provided an indexable cutting tool having a curved cutting insert and capable of stable machining in machining applications other than grooving. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a partial perspective view of an indexable cutting tool according to an embodiment. [Figure 2A] FIG. 2A is a perspective view of a cutting insert according to an embodiment. [Figure 2B] FIG. 2B is a side view of the cutting insert. [Diagram 3] FIG. 3 is a partial side view of the indexable cutting tool according to the embodiment. [Figure 4] FIG. 4 is a schematic explanatory view of a copy machining process using the indexable cutting tool of the embodiment. [Diagram 5] FIG. 5 is a side view of a cutting tool of a first modified example. [Figure 6A] FIG. 6A is a plan view of a cutting insert according to a first modified example. [Figure 6B] FIG. 6B is a side view of the cutting insert of the first modified example. [Figure 7A] FIG. 7A is a plan view of a cutting insert according to a second modified example. [Figure 7B] FIG. 7B is a side view of the cutting insert of the second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Fig. 1 is a partial perspective view of an indexable cutting tool according to an embodiment. Fig. 2A is a perspective view of a cutting insert according to an embodiment, Fig. 2B is a side view of the cutting insert. Fig. 3 is a partial side view of an indexable cutting tool according to an embodiment.

[0014] The indexable cutting tool 100 shown in FIG. The holder 1 has a rectangular prism-shaped shank portion 2 and a head portion 3 connected to the longitudinal tip of the shank portion 2. The holder 1 is made of, for example, steel. In this embodiment, the direction from the shank portion 2 to the head portion 3 in the indexable cutting tool 100 is called the tip side, and the direction from the head portion 3 to the shank portion 2 is called the rear end side.

[0015] As shown in Figs. 1 and 3, the head portion 3 has a slit 3a extending from the tip of the head portion 3 toward the shank portion 2. The portion of the head portion 3 above the slit 3a is the upper jaw portion 3b, and the portion below the slit 3a is the lower jaw portion 3c. As shown in Fig. 3, the shank portion 2 is connected to the rear of the lower jaw portion 3c of the head portion 3. The height position of the slit 3a roughly coincides with the height position of the upper surface 2b of the shank portion 2. The connection 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 with the connection portion 3d as a fulcrum.

[0016] The lower jaw 3c has a generally rectangular plate-shaped pedestal 4 at its tip. A pedestal surface 5 consisting of a flat surface having a rectangular shape in a plan view is formed on the upper surface of the pedestal 4. The pedestal surface 5 extends from the tip of the lower jaw 3c in the longitudinal direction of the holder 1 to the middle of the slit 3a.

[0017] The upper jaw 3b has a pressing portion 6 at the tip of the upper jaw 3b. The pressing portion 6 is a triangular plate in a side view that tapers toward the tip. The tip of the pressing portion 6 is located rearward of the tip of the lower jaw 3c. A pressing surface 7 is formed on the surface of the pressing portion 6 facing the base 4. The pressing surface 7 extends from the tip of the upper jaw 3b to the middle of the slit 3a. The rear end of the pressing surface 7 is located tipward of the rear end of the base surface 5. The upper jaw 3b has a protrusion 6a on the underside of the tip of the pressing portion 6 that protrudes downward (toward the lower jaw 3c) from the pressing surface 7. The protrusion 6a is a linear protrusion that extends in a direction perpendicular to the direction in which the pressing surface 7 extends.

[0018] In the holder 1, the seat surface 5 of the seat portion 4 and the pressing surface 7 of the pressing portion 6 are disposed opposite to each other in the vertical direction.

[0019] The holder 1 is provided with a clamp screw 22 that is inserted from above into the head portion 3 at the tip of the holder 1 as a clamping means for the insert mounting seat 8. The clamp screw 22 passes through the slit 3a from the upper jaw portion 3b side and is tightened into a screw hole in the lower jaw portion 3c. By tightening the clamp screw 22, the cutting insert 10 that is inserted between the upper jaw portion 3b and the lower jaw portion 3c can be fixed.

[0020] The cutting insert 10 is fixed by being sandwiched vertically between the base portion 4 and the pressing portion 6 of the insert mounting seat 8. The cutting insert 10 is made of, for example, a cemented carbide alloy. As shown in Figures 2A and 2B, the cutting insert 10 is a cutting insert having a shape bent into an L-shape in a plan view. The cutting insert 10 has a rod-shaped main body 12 extending along a first direction d1 from a corner of the L-shape as a base point, and a rod-shaped cutting edge portion 16 extending along a second direction d2 perpendicular to the first direction d1. The two-dot chain line shown in Figure 2A conveniently shows the boundary between the main body 12 and the cutting edge portion 16 in this embodiment.

[0021] In this embodiment, the body portion 12 and the cutting edge portion 16 are part of a single-member cutting insert 10. The cutting insert 10 has a roughly rectangular prism-shaped body portion 12 extending along a first direction d1, and a roughly rectangular prism-shaped cutting edge portion 16 protruding in a second direction d2 from a side surface of the body portion 12 on the base end side in the first direction d1.

[0022] The upper surface of the cutting insert 10 is a pressed surface 14 that faces the pressing surface 7 of the pressing portion 6. In this 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 that faces the base surface 5 of the base portion 4. In this embodiment, the lower surface of the main body portion 12 is the seating surface 15.

[0023] The cutting edge portion 16 extends along a second direction d2 perpendicular to the main body portion 12. A cutting edge 17 is formed on three sides of the upper surface end of the cutting edge portion 16. The cutting edge 17 is formed on a side extending substantially parallel to the longitudinal direction (first direction d1) of the main body portion 12 at the tip portion of the upper surface of the cutting edge portion 16 and two sides adjacent to this side extending along the direction in which the cutting edge portion 16 extends (second direction d2). A side surface of the cutting edge portion 16 continuing to the cutting edge 17 is defined as a clearance surface 18 of the cutting edge 17. An upper surface portion of the cutting edge portion 16 continuing to the cutting edge 17 is defined as a rake surface 19. In this embodiment, the rake surface 19 is a trapezoidal shape that widens toward the tip of the cutting edge portion 16 in a plan view.

[0024] A groove 11 is formed from the end of the rake face 19 on the body portion 12 side along the direction in which the cutting edge portion 16 extends (second direction d2). The end of the groove 11 opposite the rake face 19 reaches the side surface of the body portion 12 opposite the cutting edge portion 16. The groove 11 is formed on the upper surface of the portion where the cutting insert 10 bends.

[0025] In a vertical cross section along the first direction d1, the groove 11 is formed in a V shape by a pair of inclined surfaces 11a, 11b which move away from each other toward the upper side. In the case of this embodiment, the height position of the upper end of the groove 11 approximately coincides with the height position of the pressed surface 14. The height position of the scooping surface 19 is lower than the height position of the upper end of the groove 11. The height position of the scooping surface 19 approximately coincides with the height position of the bottom of the groove 11. Between the area where the groove 11 is formed and the scooping surface 19, an inclined surface 16a is formed which descends from the upper end of the groove 11 toward the scooping surface 19.

[0026] In this embodiment, the inclined surfaces 11a and 11b are convex curved surfaces that are slightly convex upward when viewed from the side in the second direction d2 as shown in Fig. 2B. The cross-sectional shape of the inclined surfaces 11a and 11b is not particularly limited, and may be a flat surface or a concave curved surface.

[0027] The cutting insert 10 is attached by inserting the main body 12 into the insert mounting seat 8. With the seating surface 15 of the cutting insert 10 supported from below by the seating surface 5 of the insert mounting seat 8, the clamp screw 22 is tightened, whereby the pressing surface 7 of the pressing part 6 is pressed against the pressed surface 14 of the cutting insert 10. As a result, the cutting insert 10 is fixed in a sandwiched state between the upper jaw part 3b and the lower jaw part 3c.

[0028] 3, in this embodiment, the protrusion 6a of the upper jaw portion 3b is disposed in the recessed groove 11 of the cutting insert 10. The protrusion 6a is disposed at a position facing the upper surface of the inclined surface 11a of the cutting insert 10. It is preferable that the protrusion 6a and the inclined surface 11a are in contact with each other or are separated from each other with a small gap therebetween.

[0029] According to the indexable cutting tool 100 of this embodiment having the above-mentioned configuration, the recessed groove 11 is provided on the upper surface of the cutting insert 10, and the protrusion 6a is provided on the tip of the upper jaw portion 3b of the holder 1. As a result, the protrusion 6a is disposed in the recessed groove 11 of the cutting insert 10 sandwiched between the upper jaw portion 3b and the lower jaw portion 3c.

[0030] 4 is a schematic explanatory diagram of copy machining using the indexable cutting tool 100 of this embodiment. In copy machining, a groove having a complex shape is formed on the outer peripheral surface or inner peripheral surface of the workpiece W while moving the workpiece W and the indexable cutting tool 100 relatively in the axial direction along the rotation axis O of the workpiece W. Therefore, a force is applied to the cutting insert 10 in a direction to pull the cutting insert 10 out of the holder 1 in the axial direction (longitudinal direction of the main body 12).

[0031] In the conventional clamping structure of L-shaped inserts, the upper and lower surfaces were simply pressed to fix the insert, so if a force was applied in the direction of pulling the cutting insert out of the insert mounting seat 8, there was a risk that the cutting insert would shift from its correct clamped position. In contrast, in the present embodiment, the protrusion 6a of the holder 1 is arranged within the groove 11 of the cutting insert 10, so that even if a force acts on the cutting insert 10 in the direction of pulling it out during copying, the protrusion 6a gets caught on the inclined surface 11a of the groove 11, preventing the position of the cutting insert 10 from moving.

[0032] Therefore, according to this embodiment, it is possible to suppress the positional deviation of the cutting insert 10 during machining, and it is possible to stably perform a variety of types of machining including copy machining using the L-shaped cutting insert 10.

[0033] In this embodiment, the protrusion 6a provided on the holder 1 is a linear protrusion extending in a direction perpendicular to the longitudinal direction (first direction d1) of the main body 12. With this configuration, the area in which the inclined surface 11a of the recessed groove 11 and the protrusion 6a face each other is increased, so that the protrusion 6a is more likely to be caught in the recessed groove 11. Since the cutting insert 10 can be more stably held in the insert mounting seat 8, the machining stability of the indexable cutting tool 100 can be further improved. The shape of the protrusion 6a is not limited to a linear protrusion, and may be, for example, a configuration consisting of a single or multiple dot-shaped protrusions.

[0034] (First Modification) Hereinafter, a cutting tool 100A of a first modified example will be described with reference to FIGS. Fig. 5 is a side view of a cutting tool 100A of a first modified example including a cutting insert 10A and a holder 1A. Fig. 6A is a plan view of the cutting insert 10A of the first modified example. Fig. 6B is a side view of the cutting insert 10A of the first modified example. In Figure 5 and Figures 6A and 6B, the same reference numerals are used to designate components common to Figures 1 to 4. In the following description, description of components similar to those in the previous embodiment will be omitted where appropriate.

[0035] As shown in FIG. 5, a cutting tool 100A of a first modified example includes a cutting insert 10A and a holder 1A that holds the cutting insert 10A. As shown in Fig. 5 and Figs. 6A and 6B, the cutting insert 10A has a groove 11A on the upper surface of the rectangular columnar portion of the main body portion 12. That is, the cutting insert 10A has the groove 11A at a position away from the portion where the cutting insert 10A is bent. In the present embodiment, the groove 11A is disposed slightly toward the tip side (the side where the cutting edge portion 16 is disposed) from the center of the main body portion 12 in the longitudinal direction (first direction d1) of the main body portion 12. The area of ​​the upper surface of the main body portion 12 other than the groove 11 is a flat surface.

[0036] Of the upper surface of the cutting portion 16, the region on the main body portion 12 side is a flat surface 16b at the same height as the upper surface of the main body portion 12. Of the upper surface of the cutting portion 16, the region on the tip side in the direction in which the cutting portion 16 extends (second direction d2) is a rake surface 19. Between the flat surface 16b of the cutting portion 16 and the rake surface 19, an inclined surface 16a is formed that descends from the flat surface 16b toward the rake surface 19.

[0037] The holder 1A is different from the holder 1 of the previous embodiment in the position of the protrusion 6a provided on the upper jaw 3b. As shown in FIG. 5, in the holder 1A of the first modification, the protrusion 6a is provided near the longitudinal center of the lower surface (the surface facing the base surface 5) of the pressing portion 6 of the upper jaw 3b. The protrusion 6a is a linear protrusion extending in a direction perpendicular to the direction in which the pressing portion 6 extends. The area of ​​the lower surface of the pressing portion 6 other than the protrusion 6a is the pressing surface 7 consisting of a flat surface. Therefore, the lower surface of the pressing portion 6 of the first modification is divided into two pressing surfaces 7 by the protrusion 6a.

[0038] The cutting insert 10A is attached to the insert mounting seat 8 of the holder 1A, as in the previous embodiment. The seating surface 5 of the holder 1A supports the seating surface 15 of the cutting insert 10A from below. The pressing surface 7 of the holder 1A presses the pressed surface 14 of the cutting insert 10A from above. The protrusion 6a of the pressing portion 6 is disposed in the recessed groove 11A on the upper surface of the cutting insert 10A. In this manner, the cutting insert 10A is fixed to the insert mounting seat 8 of the holder 1A.

[0039] According to the indexable cutting tool 100A of the first modified example having the above configuration, the cutting insert 10A is fixed to the insert mounting seat 8 of the holder 1A with the protrusion 6a disposed in the recessed groove 11A on the upper surface of the cutting insert 10A. As a result, even if a force acts in a direction to pull the cutting insert 10A out of the insert mounting seat 8 during copying, the protrusion 6a gets caught on the side surface of the recessed groove 11A, so that the cutting insert 10A can be prevented from moving in position.

[0040] Therefore, also in the first modified example, it is possible to suppress the positional deviation of the cutting insert 10A during machining, and it is possible to stably perform a variety of types of machining including copy machining by using the L-shaped cutting insert 10A.

[0041] (Second Modification) The second modified example will be described below with reference to FIGS. 7A and 7B. Fig. 7A is a plan view of a cutting insert 10B of a second modified example, and Fig. 7B is a side view of the cutting insert 10B of the second modified example. 7A and 7B, the same components as those in Fig. 1 to Fig. 6 are denoted by the same reference numerals. In the following description, the description of the same components as those in the previous embodiment and the first modified example will be omitted as appropriate.

[0042] As shown in FIGS. 7A and 7B, the cutting insert 10B has a groove 11B on the upper surface of the rectangular columnar portion of the main body 12. That is, the cutting insert 10B has the groove 11B at a position away from the portion where the cutting insert 10B bends. The area on the upper surface of the main body 12 other than the groove 11 is a flat surface. The shape and the formation position of the groove 11B of the second modification are the same as those of the groove 11A of the first modification. That is, the cutting insert 10B of the second modification can be attached to the holder 1A of the first modification.

[0043] The cutting insert 10B is a cutting insert having a bent shape in which the cutting edge portion 16B extends from the tip of the body portion 12 in a direction (second direction d2) intersecting with the longitudinal direction (first direction d1) of the body portion 12. In the second modification, the cutting edge portion 16B extends in a 45° direction with respect to the body portion 12. That is, the intersecting angle θ between the first direction d1 and the second direction d2 is 45°. The intersecting angle θ is not limited to 45° and can be set to any angle within a range in which the cutting insert 10B having a bent shape can be manufactured.

[0044] The cutting edge portion 16B has a cutting edge 17B that is arc-shaped in a plan view. A rake face 19B of the cutting edge 17B is provided with a plurality of breaker projections. A flank face 18B of the cutting edge 17B is a tapered surface whose diameter decreases toward the lower side. The shape of the cutting edge 17 is not particularly limited, and any known cutting edge shape can be applied.

[0045] The cutting insert 10B of the second modification can be used by being attached to the holder 1A of the first modification. Since a groove 11B is formed on the upper surface of the cutting insert 10B, when the cutting insert 10B is attached to the insert mounting seat 8 of the holder 1A, the protrusion 6a of the pressing part 6 is disposed in the groove 11B. As a result, as in the first modification, even if a force acts in a direction to pull the cutting insert 10B out of the insert mounting seat 8 during copying, the groove 11B and the protrusion 6a can prevent the clamping position of the cutting insert 10B from shifting. [Explanation of symbols]

[0046] 1,1A…Holder 2…Shank 3…Head section 3a…Slit 3b...Maxillary part 3c…Mandibular part 3d…Connection part 4…Pedestal 5…Pedestal surface 6…Pressing part 6a…Protrusion 7...Pressing surface 8…Insert mounting seat 10, 10A, 10B...Cutting insert 11,11A,11B…Concave groove 11a,16a...Slope surface 12...Main body 14...Pressurized surface 15…Seating surface 16,16B…Cutting blade part 16b…Flat surface 17,17B…Cutting blade 18,18B…flank 19,19B…Scooping surface 22…Clamp screw 100,100A…Replaceable cutting tools d1…first direction d2…Second direction O…Rotation axis W…Work material θ…Intersection angle

Claims

1. A cutting tool having an indexable cutting edge, comprising: a holder having an insert mounting seat having a pressing surface and a seating surface opposed to each other; and a cutting insert held by the insert mounting seat and having a pressed surface and a seating surface in contact with the pressing surface and the seating surface, respectively, the cutting insert has, in a plan view with the seating surface as a lower surface, a rod-shaped main body portion and a cutting edge portion extending from a tip end of the main body portion in a direction intersecting with the main body portion, and has a groove extending in a direction perpendicular to a direction in which the main body portion extends on an upper surface of the cutting insert on which the pressed surface is provided, The holder includes an upper jaw portion and a lower jaw portion that grip the cutting insert, the lower jaw portion has the seat surface on a surface facing the upper jaw portion, The upper jaw portion has, on a surface facing the lower jaw portion, the pressing surface and a protrusion portion protruding toward the lower jaw portion and disposed in the groove of the cutting insert. Indexable cutting tool.

2. The indexable cutting tool according to claim 1 , wherein the protrusion is a linear protrusion extending in a direction in which the recessed groove extends.

3. 3. The indexable cutting tool according to claim 1, wherein the cutting insert has the groove on an upper surface of a portion where the cutting insert is bent.

4. The indexable cutting tool according to claim 1 or 2, wherein the cutting insert has the concave groove on an upper surface thereof at a position away from a portion where the cutting insert is bent.

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