Cutting inserts, holders, and cutting tools

Abstract

To provide a cutting insert which can be attached to a holder easily and stably and process a workpiece precisely, and to provide the holder and a cutting tool.SOLUTION: A cutting tool 100 is used when a workpiece W is cut and includes: a holder 50; and a cutting insert 10 which is attached to a tip of the holder 50. The holder 50 has: an insert pocket 53 in which the cutting insert 10 is fitted; and a stopper part 61 which elastically engages with the cutting insert 10 fitted in the insert pocket 53. The cutting insert 10 has: a cutting part 11 having a cutting edge 13; a fitting part 12 configured to be fitted in the insert pocket 53; and an engagement part 21 formed in the fitting part 12 and configured to be engaged with the stopper part 61 of the holder 50.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a cutting insert, a holder, and a cutting tool.

Background Art

[0002] Patent Document 1 discloses an internal turning tool in which a diamond-shaped insert having a cutting edge is screwed to the tip of a rod-shaped holder.

[0003] Further, Patent Documents 2 and 3 disclose a cutting tool in which an elongated mounting hole (insertion hole) is formed at the tip of a holder, and a rod-shaped cutting insert having a cutting edge is inserted into the mounting hole and screwed.

[0004] Furthermore, Patent Document 4 discloses a cutting tool in which an insert is press-fitted and assembled into an insert receiving slot of a holder blade, and Patent Document 5 discloses a cutting tool in which a cutting insert is fitted into an insert pocket of an insert holder.

Prior Art Literature

Patent Literature

[0005]

Patent Literature 1

Patent Literature 2

Patent Literature 3

Patent Literature 4

Patent Literature 5

Summary of Invention

Problem to be Solved by the Invention

[0006] However, in the cutting tool described in Patent Document 1, there is a limit to how thin the holder can be made due to the need to secure screw threads for clamping the tip in the holder, making it difficult to reduce the minimum machining diameter. In such replaceable tip internal diameter cutting tools for machining small parts, extremely small screws are used for clamping, which makes the screws prone to falling out or getting lost, posing a challenge in terms of ease of installation.

[0007] Furthermore, as described in Patent Documents 2 and 3, even in the case of tools equipped with a rod-shaped cutting insert having a cutting edge, a small screw is used to position the rod-shaped cutting insert. In particular, because the cutting insert is a thin rod, the screw is difficult to handle, and there are challenges in the workability of attaching the cutting insert to the holder.

[0008] Furthermore, while Patent Documents 4 and 5 describe tools with a structure that allows cutting inserts to be attached to pockets in a holder without using screws, the mounting strength of the cutting inserts to the holder is not stable, and the cutting inserts may fluctuate during machining of the workpiece, potentially making it difficult to achieve good machining.

[0009] The present invention has been made in view of the above circumstances, and aims to provide a cutting insert, holder, and cutting tool that can be easily and stably mounted on a holder and that can process a workpiece well. [Means for solving the problem]

[0010] To achieve the above objective, the cutting insert of the present invention is A cutting insert that is attached to the tip of the holder, A cutting section having a cutting edge, A fitting portion that fits into an insert pocket formed in the holder, It has, The fitting portion has a recessed locking portion that engages with a part of the holder.

[0011] With this configuration of the cutting insert, the recessed locking portion of the mating part is locked to a part of the holder, so compared to a structure in which the cutting insert is attached to the holder with screws, the cutting insert can be attached to the holder more easily and stably. This improves the workability of attaching the cutting insert to the holder and eliminates problems such as screws falling out or getting lost.

[0012] Furthermore, the cutting insert of the present invention is The inner surface of the insert pocket has a contact surface that abuts against and restrains it from the holder.

[0013] With this configuration of cutting insert, the contact surface is held in contact with the inner surface of the insert pocket. This increases the holding force of the cutting insert against the holder and suppresses fluctuations in the workpiece during machining.

[0014] Furthermore, the cutting insert of the present invention is The aforementioned cutting portion is A horizontal cutting blade is provided on the side, A front cutting edge is provided at the front, It has, The angle between the aforementioned lateral cutting edge and the aforementioned front cutting edge is 25° or more and 80° or less.

[0015] With this cutting insert configuration, the angle between the lateral cutting edge and the front cutting edge is between 25° and 80°, making it possible to use it as a substitute for rhombic inserts standardized by ISO, and enabling the same cutting processes as those performed with such rhombic inserts.

[0016] To achieve the above objective, the holder of the present invention is A holder with a cutting insert attached to its tip, The insert pocket into which the cutting insert is fitted, A stopper portion that elastically locks the cutting insert fitted into the insert pocket, It holds.

[0017] According to the holder having this configuration, since it adopts a structure in which the cutting insert fitted into the insert pocket is elastically locked and mounted by the stopper portion, the cutting insert can be easily and stably mounted on the holder compared with a structure in which the cutting insert is mounted on the holder by screws. This can improve the workability of mounting the cutting insert to the holder, and eliminate problems such as screw dropping and loss. Moreover, since screw threads can be eliminated, the holder can be reduced in diameter, and processing of small parts is enabled.

[0018] Further, the holder of the present invention is a slit along the fitting direction of the cutting insert into the insert pocket is formed on the insert pocket side of the stopper portion.

[0019] According to the holder having this configuration, by forming a slit along the fitting direction of the cutting insert into the insert pocket on the insert pocket side of the stopper portion, the stopper portion can be favorably elastically deformable.

[0020] Further, the holder of the present invention is the stopper portion has a convex portion that engages with a concave locking portion formed on the cutting insert fitted into the insert pocket.

[0021] According to the holder having this configuration, when the cutting insert is fitted into the insert pocket, the convex portion of the elastically deformed stopper portion engages with the concave locking portion of the cutting insert. This allows the cutting insert to be pulled into the insert pocket. In addition, when the convex portion of the stopper portion engages with the concave locking portion of the cutting insert, the elastically deformed stopper portion restores its shape, so the completion of mounting of the cutting insert can be easily perceived by the sensation (the so-called click feeling) when the stopper portion restores its shape.

[0022] Further, the holder of the present invention is The insert pocket has a restraining surface that contacts the outer surface of the cutting insert and holds the cutting insert.

[0023] With this holder configuration, the cutting insert fitted into the insert pocket can be held in place by the restraining surface. This increases the holding force of the cutting insert and suppresses movement of the cutting insert during machining of the workpiece.

[0024] Furthermore, the holder of the present invention is A keyhole is formed in the insert pocket that communicates with the front side of the cutting insert in the fitting direction.

[0025] With this holder configuration, for example, by pushing a pin into the keyhole and pushing the cutting insert, which is fitted and installed in the insert pocket, in the opposite direction to the fitting direction, the locking of the cutting insert by the stopper can be released. As a result, the cutting insert can be easily removed from the holder compared to a structure in which the cutting insert is attached with a screw.

[0026] To achieve the above objective, the cutting tool of the present invention is A cutting tool used when machining a workpiece, Holder and, A cutting insert is attached to the tip of the holder, Equipped with, The aforementioned holder is, The insert pocket into which the cutting insert is fitted, A stopper portion that elastically locks the cutting insert fitted into the insert pocket, It has, The aforementioned cutting insert is A cutting section having a cutting edge, A fitting portion that fits into the aforementioned insert pocket, A locking portion formed in the fitting portion and engaging with the stopper portion of the holder, It holds.

[0027] With this cutting tool configuration, the cutting insert, which is fitted into the insert pocket, is elastically secured and mounted by the stopper portion. Compared to a structure where the cutting insert is mounted to the holder with screws, this allows for easier and more stable mounting of the cutting insert to the holder. This improves the ease of mounting the cutting insert to the holder and eliminates problems such as screws falling out or getting lost. Moreover, since screw threads are unnecessary, the holder can be made smaller in diameter, enabling the machining of small parts.

[0028] Furthermore, the cutting tool of the present invention is A slit is formed on the insert pocket side of the stopper portion, along the direction in which the cutting insert is fitted into the insert pocket.

[0029] With this cutting tool configuration, by forming a slit on the insert pocket side of the stopper portion that is aligned with the direction in which the cutting insert is fitted into the insert pocket, the stopper portion can be elastically deformed effectively.

[0030] Furthermore, the cutting tool of the present invention is The stopper portion has a protrusion that engages with the concave locking portion formed on the cutting insert that is fitted into the insert pocket.

[0031] With this cutting tool configuration, when the cutting insert is fitted into the insert pocket, the convex portion of the elastically deformed stopper portion engages with the concave locking portion of the cutting insert. This allows the cutting insert to be pulled into the insert pocket. Furthermore, when the convex portion of the stopper portion engages with the concave locking portion of the cutting insert, the elastically deformed stopper portion returns to its original shape. The sensation (so-called click) when the stopper portion returns to its original shape makes it easy to determine that the cutting insert has been successfully installed.

[0032] Furthermore, the cutting tool of the present invention is The insert pocket of the holder has a restraining surface, The cutting insert has a contact surface that is held in the holder by the restraining surface when the fitting portion is fitted into the insert pocket.

[0033] With this cutting tool configuration, the cutting insert fitted into the insert pocket can be held in place by the restraining surface. This increases the holding force of the cutting insert and suppresses movement of the cutting insert during machining of the workpiece.

[0034] Furthermore, the cutting tool of the present invention is The holder has a keyhole that communicates with the front side of the cutting insert in the fitting direction within the insert pocket.

[0035] With this cutting tool configuration, for example, by pushing a pin into the keyhole and pushing the cutting insert, which is fitted and installed in the insert pocket, in the opposite direction to the fitting direction, the locking of the cutting insert by the stopper can be released. As a result, the cutting insert can be easily removed from the holder compared to a structure in which the cutting insert is attached with a screw.

[0036] Furthermore, the cutting tool of the present invention is The aforementioned cutting portion is A horizontal cutting blade is provided on the side, A front cutting edge is provided at the front, It has, The angle between the aforementioned lateral cutting edge and the aforementioned front cutting edge is 25° or more and 80° or less.

[0037] With this cutting tool configuration, the angle between the lateral cutting edge and the front cutting edge of the cutting insert is between 25° and 80°, making it possible to use it as a substitute for the rhomboid inserts standardized by ISO, and enabling cutting operations similar to those performed with cutting tools equipped with such rhomboid inserts.

[0038] Furthermore, the cutting tool of the present invention is The aforementioned cutting edge has a cutting angle of 60° to 145° relative to the workpiece during cutting.

[0039] With this cutting tool configuration, the cutting angle of the front cutting edge relative to the workpiece during cutting is between 60° and 145°. Therefore, it can be used as a substitute for rhomboid inserts standardized by ISO, and can perform cutting operations similar to those performed with cutting tools equipped with such rhomboid inserts. [Effects of the Invention]

[0040] According to the present invention, it is possible to provide a cutting insert, holder, and cutting tool that can be easily and stably mounted on a holder and perform good machining on a workpiece. [Brief explanation of the drawing]

[0041] [Figure 1] This is a perspective view of the cutting tool according to this embodiment. [Figure 2] This is an exploded perspective view of the cutting tool according to this embodiment. [Figure 3] This is a plan view of the tip of a cutting tool. [Figure 4] This is a cross-sectional view of the cutting insert, taken from the side, along the axial direction of the holder. [Figure 5] This is a perspective view of a cutting insert. [Figure 6] This is a perspective view of the cutting insert from below. [Figure 7] This is a plan view of a cutting insert. [Figure 8] This is a side view of a cutting insert. [Figure 9] This is a front view of the cutting insert. [Figure 10] This is a view of the back of the cutting insert. [Figure 11] This is a perspective view of the holder. [Figure 12] This is a perspective view of the insert mounting section of the holder. [Figure 13]This is a perspective view of the insert mounting section of the holder, seen from below. [Figure 14] This is a perspective view from below of the stopper portion provided in the insert mounting section. [Figure 15] This is a plan view of the insert mounting section of the holder. [Figure 16] This is a cross-sectional view AA in Figure 15. [Modes for carrying out the invention]

[0042] Embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a perspective view of the cutting tool according to this embodiment. Figure 2 is an exploded perspective view of the cutting tool according to this embodiment. Figure 3 is a plan view of the tip of the cutting tool. Figure 4 is a cross-sectional view of the cutting insert along the axial direction of the holder, viewed from the side.

[0043] As shown in Figures 1 to 4, the cutting tool 100 according to this embodiment has a cutting insert 10 and a holder 50. This cutting tool 100 has the cutting insert 10 mounted on the tip of the holder 50, and is a turning tool for cutting the inner diameter of a rotating workpiece by cutting the inner diameter portion with the cutting insert 10 at the tip of the holder 50.

[0044] Figure 5 is a perspective view of the cutting insert. Figure 6 is a perspective view of the cutting insert from below. Figure 7 is a top view of the cutting insert. Figure 8 is a side view of the cutting insert. Figure 9 is a front view of the cutting insert. Figure 10 is a back view of the cutting insert.

[0045] As shown in Figures 5 to 10, the cutting insert 10 has a cutting portion 11 and a fitting portion 12. The fitting portion 12 is integrally molded with the rear of the cutting portion 11 and extends rearward from the cutting portion 11. The cutting portion 11 is formed to protrude from both sides of the fitting portion 12.

[0046] The cutting insert 10 is formed from various materials such as cemented carbide, cermet, ceramics, ultra-high pressure sintered body, or diamond.

[0047] The cutting section 11 has a cutting edge 13 at one corner on the upper side of its front end. The cutting section 11 also has a breaker 14 above the cutting edge 13. This cutting edge 13 has a lateral cutting edge 15 and a front cutting edge 16. The top surface of the cutting section 11 is a rake face 17, one side is a lateral relief face 18, and the front surface is a front relief face 19. The lateral cutting edge 15 is formed between the rake face 17 and the lateral relief face 18, and the front cutting edge 16 is formed between the rake face 17 and the front relief face 19.

[0048] Thus, the cutting section 11 has a lateral cutting edge 15 and a front cutting edge 16, and the angle θ1 between the lateral cutting edge 15 and the front cutting edge 16 is set to be between 25° and 80° (see Figure 7).

[0049] The fitting portion 12 has a locking portion 21 at its lower part. The locking portion 21 is formed in a concave shape when viewed from the side. The rearward inclined surface on the inner surface of this locking portion 21 is the locking surface 22. The fitting portion 12 also has a sliding surface 23 at its lower part, rearward from the locking portion 21, which gradually slopes upward toward the rear end. The fitting portion 12 also has a tapered surface 24 at the upper part of its rear end. This tapered surface 24 gradually slopes upward toward the front from the rear end of the fitting portion 12.

[0050] The cutting insert 10 has an upper ridge 31 and a lower ridge 32 extending in the front-rear direction at its upper and lower ends. The upper ridge 31 is formed on the fitting portion 12 of the cutting insert 10, and the lower ridge 32 is formed extending from the cutting portion 11 of the cutting insert 10 to a part of the fitting portion 12.

[0051] The upper protruding portion 31 has upper contact surfaces (contact surfaces) 31a and 31b formed along the direction of extension at both corners in a cross-sectional view. Similarly, the lower protruding portion 32 has lower contact surfaces (contact surfaces) 32a and 32b formed along the direction of extension at both corners in a cross-sectional view.

[0052] Furthermore, the rear surface of the cutting insert 10 on the fitting portion 12 side of the cutting portion 11 is designated as a side contact surface (contact surface) 33a, 33b, respectively.

[0053] Figure 11 is a perspective view of the holder. Figure 12 is a perspective view of the insert mounting portion of the holder. Figure 13 is a perspective view of the insert mounting portion of the holder viewed from below. Figure 14 is a perspective view of the stopper portion provided on the insert mounting portion viewed from below. Figure 15 is a plan view of the insert mounting portion of the holder. Figure 16 is a cross-sectional view of AA in Figure 15.

[0054] As shown in Figures 11 to 16, the holder 50 is formed in a cylindrical shape, and a cutting insert 10 is mounted on its tip. The holder 50 has a shank portion 51 and an insert mounting portion 52. The insert mounting portion 52 is formed to have a smaller diameter than the shank portion 51.

[0055] This holder 50 is made of a metal material such as steel. Preferred materials for this holder 50 include, for example, alloy tool steel (SKS5), die steel (SKD61), and maraging steel, which are elastic and resistant to plastic deformation.

[0056] The holder 50 is fabricated, for example, by a metal powder sintering 3D printer that fabricates objects in three dimensions using metal powder. Examples of fabrication methods using a metal powder sintering 3D printer include powder bed fusion, electron beam melting (EBM), which melts the powder using an electron beam, or selective laser melting (SLM), which melts the powder using laser light.

[0057] The insert mounting portion 52 of the holder 50 has an insert pocket 53 at its tip. This insert pocket 53 is made up of a hole formed on the end face of the insert mounting portion 52, and the cutting insert 10 is fitted into this insert pocket 53 from the fitting portion 12 side. In addition, a notch 54 is formed at the upper end of the end of the insert mounting portion 52, and a part of the insert pocket 53 is exposed.

[0058] The insert mounting portion 52 has a stopper portion 61 at its lower part. An opening 62 is provided at the lower part of the insert mounting portion 52, and the stopper portion 61 is positioned in this opening 62.

[0059] The stopper portion 61 extends in the longitudinal direction of the insert pocket 53. This stopper portion 61 is formed in the shape of a single-support beam, with its leading end being a free end 63 and its rear end being a base end 64 connected to the holder 50. This stopper portion 61 has a projection 65 at its free end 63 that protrudes toward the insert pocket 53. This projection 65 is capable of engaging with a locking portion 21 formed on the fitting portion 12 of the cutting insert 10 that is fitted into the insert pocket 53. The rearward inclined surface of the outer surface of this projection 65 is a locking surface 66.

[0060] The insert mounting portion 52 has a slit 67 formed on the insert pocket 53 side of the stopper portion 61, which is aligned with the direction in which the fitting portion 12 of the cutting insert 10 into the insert pocket 53 is inserted. This allows the stopper portion 61 to be easily elastically deformed.

[0061] The insert mounting portion 52 has an upper concave portion 71 and a lower concave portion 72. The upper concave portion 71 is formed on the upper part of the inner surface of the insert pocket 53, and the lower concave portion 72 is formed on the lower part of the inner surface of the insert pocket 53. These upper concave portion 71 and lower concave portion 72 are each formed in an arc shape in cross-section, and their respective inner surfaces are the upper restraint surface (restraint surface) 71a and lower restraint surface (restraint surface) 72a. The upper ridge portion 31 and lower ridge portion 32 of the cutting insert 10, which is mounted on the insert mounting portion 52, fit into these upper concave portion 71 and lower concave portion 72. As a result, the upper restraint surface 71a of the upper concave portion 71 and the lower restraint surface 72a of the lower concave portion 72 contact the upper contact surfaces 31a, 31b and lower contact surfaces 32a, 32b formed on the upper ridge portion 31 and lower ridge portion 32 of the cutting insert 10.

[0062] Furthermore, the insert mounting portion 52 has side restraint surfaces (restraint surfaces) 73a and 73b on both sides of its end face. These side restraint surfaces 73a and 73b contact the side contact surfaces 33a and 33b of the cutting insert 10 that is mounted on the insert mounting portion 52.

[0063] Furthermore, the insert mounting portion 52 has a keyhole 75. This keyhole 75 is formed on the upper part of the insert mounting portion 52 and communicates with the front side in the fitting direction of the cutting insert 10 in the insert pocket 53.

[0064] Next, we will explain how to attach the cutting insert 10 to the holder 50. To mount the cutting insert 10 onto the holder 50, bring the cutting insert 10 close to the insert mounting portion 52 of the holder 50 from its tip side. At this time, orient the fitting portion 12 of the cutting insert 10 toward the holder 50, and align the vertical position of the cutting insert 10 with the holder 50 (see Figure 2).

[0065] Then, the fitting portion 12 of the cutting insert 10 is inserted into the insert pocket 53 formed in the insert mounting portion 52 of the holder 50. In this way, the upper protrusion 31 and lower protrusion 32 of the cutting insert 10 engage with the upper recessed portion 71 and lower recessed portion 72 formed in the insert mounting portion 52 of the holder 50.

[0066] In this state, the cutting insert 10 is pushed towards the holder 50 with a finger. As a result, the cutting insert 10 moves towards the back of the insert pocket 53, with the upper protrusion 31 and lower protrusion 32 being guided by the upper concave portion 71 and lower concave portion 72.

[0067] Furthermore, when the cutting insert 10 is pushed into the insert pocket 53, the sliding surface 23 of the cutting insert 10 comes into contact with the protrusion 65 of the stopper portion 61 of the holder 50 and slides against it. If the cutting insert 10 is pushed further from this state, the fitting portion 12 of the cutting insert 10 pushes the stopper portion 61 outward (downward in the plane of the paper in Figure 4) and elastically deforms.

[0068] Subsequently, the protrusion 65 engages with the locking portion 21 of the cutting insert 10, and the locking surface 66 of the protrusion 65 comes into contact with the locked surface 22 of the locking portion 21. As the elastically deformed stopper portion 61 returns to its original state, the locking surface 66 of the protrusion 65 slides against the locked surface 22 of the locking portion 21, and the elastic force of the returning stopper portion 61 is transmitted to the cutting insert 10 via the locked surface 22 of the locking portion 21 and the locking surface 66 of the protrusion 65, which slide against each other, causing the cutting insert 10 to be pulled into the back of the insert pocket 53 and installed.

[0069] Thus, by fitting the fitting portion 12 of the cutting insert 10 into the insert pocket 53, the clamping mechanism has a structure in which the convex portion 65 of the elastically deformed stopper portion 61 engages with the concave locking portion 21 of the cutting insert 10, allowing the cutting insert 10 to be easily pulled into the insert pocket 53.

[0070] Furthermore, when the convex portion 65 of the stopper portion 61 engages with the concave locking portion 21 of the cutting insert 10, the elastically deformed stopper portion 61 returns to its original state. The sensation (so-called click) when the stopper portion 61 returns to its original state makes it easy to determine that the cutting insert 10 has been successfully installed.

[0071] In a cutting tool 100 in which a cutting insert 10 is mounted on a holder 50, the locking surface 22 of the locking portion 21 of the cutting insert 10 mounted on the holder 50 is locked by the locking surface 66 of the protrusion 65 of the stopper portion 61 of the holder 50, thereby maintaining the mounting state of the cutting insert 10 on the holder 50 (see Figure 4).

[0072] Furthermore, in this mounted state, the upper contact surfaces 31a, 31b and lower contact surfaces 32a, 32b of the cutting insert 10 are in contact with the upper restraint surface 71a and lower restraint surface 72a of the holder 50, and the side contact surfaces 33a, 33b of the cutting insert 10 are in contact with the side restraint surfaces 73a, 73b of the holder 50. As a result, the cutting insert 10, which is fitted and mounted in the insert pocket 53 of the holder 50, is held securely in the holder 50 with high holding force and without any rattling.

[0073] When the cutting tool 100, with the cutting insert 10 mounted on the holder 50, cuts the workpiece W, the cutting angle θ2 of the front cutting edge 16 relative to the workpiece W is 60° or more and 145° or less (see Figure 3). In other words, the cutting tool 100 has a cutting edge 13 in which the angle θ1 between the side cutting edge 15 and the front cutting edge 16 is 25° or more and 80° or less, and the cutting angle θ2 of the front cutting edge 16 is 60° or more and 145° or less, allowing it to perform cutting operations on the workpiece W in the same way as a cutting tool equipped with a rhomboid insert standardized by ISO.

[0074] Here, when cutting the workpiece W, the cutting insert 10 receives a reaction force from the workpiece W that rotates around an axis perpendicular to the plane direction relative to the axial direction. Specifically, it receives a reaction force F1 from the cutting resistance from the workpiece W at the front cutting edge 16 and a reaction force F2 from the cutting resistance from the workpiece W at the side cutting edge 15 (see Figure 3).

[0075] In the cutting tool 100, when the cutting insert 10 receives reaction forces F1 and F2, the side restraining surface 73a of the holder 50, which contacts the side contact surface 33a of the cutting insert 10, receives the reaction force F1, and the side restraining surface 73b of the holder 50, which contacts the side contact surface 33b of the cutting insert 10, receives the reaction force F2. Therefore, fluctuations of the cutting insert 10 during machining of the workpiece W can be suppressed, and cutting can be performed smoothly.

[0076] Next, we will describe how to remove the cutting insert 10 from the holder 50. To remove the cutting insert 10 from the holder 50, a pin P is pushed into a keyhole 75 formed in the holder 50 (see Figure 4). The tip of the pin P then presses against the tapered surface 24 formed on the fitting portion 12 of the cutting insert 10. As a result, the stopper portion 61 is pushed outward (downward in Figure 4) and elastically deformed, and the cutting insert 10, which is fitted and installed in the insert pocket 53, is pushed out in the opposite direction to the fitting direction, releasing the locking of the cutting insert 10 by the stopper portion 61. This makes it easier to remove the cutting insert 10 from the insert pocket 53 of the holder 50 compared to a structure in which the cutting insert 10 is attached by a screw.

[0077] The keyhole 75 into which the pin P is pushed may also be an elongated hole aligned with the direction in which the cutting insert 10 fits into the insert pocket 53. In this case, by tilting the rear end of the pin P inserted into the elongated keyhole 75 toward the rear of the holder 50, the pin P is swung around the contact point with the keyhole 75 as a pivot point, and the cutting insert 10 can be easily pushed out of the insert pocket 53 and removed by the tip of the pin P.

[0078] As described above, this embodiment includes a clamping mechanism that elastically locks and secures the cutting insert 10, which is fitted into the insert pocket 53, by the stopper portion 61. Compared to a structure in which the cutting insert is attached to the holder by screws, the cutting insert 10 can be attached to the holder 50 more easily and stably. This improves the ease of attaching the cutting insert 10 to the holder 50 and eliminates problems such as screws falling out or getting lost. Moreover, since screw threads are not required, the holder 50 can be made smaller in diameter, enabling the machining of small parts.

[0079] Furthermore, this invention is not limited to internal diameter cutting, but can also be applied to turning tools for external diameter cutting, in which the outer diameter portion of a rotating workpiece is cut by a cutting insert mounted on the tip of a rectangular holder. It can also be used to perform internal diameter grooving or end face grooving by replacing the cutting edge of the cutting insert with an internal diameter grooving type or an end face grooving type. [Explanation of symbols]

[0080] 10 cutting inserts 11 Cutting part 12 Fitting part 13 cutting edge 15 horizontal cutting blades 16 Front cutting edge 21 Locking part 31a, 31b Upper contact surface (contact surface) 32a, 32b Lower contact surface (contact surface) 33a, 33b Side contact surfaces (contact surfaces) 50 holders 53 Insert Pockets 61 Stopper section 65 Convex part 67 Slits 71a Upper restraint surface (restraint surface) 72a Lower restraint surface (restraint surface) 73a, 73b Side restraint surfaces (restraint surfaces) 75 Keyhole 100 cutting tools W Workpiece θ1 angle θ2 cutting angle

Claims

1. A cutting insert that is attached to the tip of the holder, A cutting section having a cutting edge, A fitting portion that fits into an insert pocket formed in the holder, It has, The fitting portion is integrally formed with the rear of the cutting portion and extends rearward from the cutting portion. The fitting portion has, at its lower part, a contact surface against which the inner surface of the insert pocket abuts and is restrained against the holder; a locking portion located behind the contact surface, which is a concave curved surface in side view along the fitting direction and is locked to a part of the holder; and a sliding surface located behind the locking portion, which gradually slopes upward toward the rear end, wherein the contact surface, the locking portion, and the sliding surface are formed continuously along the fitting direction. Cutting insert.

2. The aforementioned cutting portion is A horizontal cutting blade is provided on the side, A front cutting edge is provided at the front, It has, The angle between the aforementioned lateral cutting edge and the aforementioned front cutting edge is 25° or more and 80° or less. The cutting insert according to claim 1.

3. A holder with a cutting insert attached to its tip, The insert pocket into which the cutting insert is fitted, A restraining surface that contacts the outer surface of the cutting insert and holds the cutting insert, A stopper portion having a curved protrusion that protrudes toward the insert pocket side in a side view along the fitting direction, which elastically locks the cutting insert that is fitted into the insert pocket, It has, The stopper portion is formed in the shape of a single support beam, with its tip being a free end and its rear end being a base end connected to the holder. It is configured to be elastically deformable independently of the restraining surface on the same side as the stopper portion when viewed from the side along the fitting direction, and the curved protrusion is formed on the free end. Holder.

4. A slit is formed in the stopper portion on the insert pocket side, along the fitting direction. The holder according to claim 3.

5. A keyhole is formed in the insert pocket that communicates with the front side of the cutting insert in the fitting direction. The holder according to claim 3.

6. A cutting tool used when machining a workpiece, Holder and A cutting insert is attached to the tip of the holder, Equipped with, The aforementioned holder is, The insert pocket into which the cutting insert is fitted, A restraining surface that contacts the outer surface of the cutting insert and holds the cutting insert, A stopper portion having a curved protrusion in a side view along the fitting direction, which elastically locks the cutting insert fitted into the insert pocket, It has, The stopper portion is formed in the shape of a single support beam, with its tip being a free end and its rear end being a base end connected to the holder, and is configured to be elastically deformable independently of the restraining surface, and the curved protrusion is formed on the free end. The aforementioned cutting insert is A cutting section having a cutting edge, A fitting portion that fits into the aforementioned insert pocket, It has, The fitting portion is integrally formed with the rear of the cutting portion and extends rearward from the cutting portion. The fitting portion has, at its lower part, a contact surface against which the restraining surface abuts and which is held by the holder; a locking portion located behind the contact surface, which is a curved surface that is concave in side view along the fitting direction and which engages with the stopper portion of the holder; and a sliding surface located behind the locking portion, which gradually slopes upward toward the rear end, wherein the contact surface, the locking portion, and the sliding surface are formed continuously along the fitting direction. cutting tools.

7. A slit is formed in the stopper portion on the insert pocket side, along the fitting direction. The cutting tool according to claim 6.

8. The holder has a keyhole that communicates with the front side of the cutting insert in the fitting direction within the insert pocket. The cutting tool according to claim 6.

9. The aforementioned cutting portion is A horizontal cutting blade is provided on the side, A front cutting edge is provided at the front, It has, The angle between the aforementioned lateral cutting edge and the aforementioned front cutting edge is 25° or more and 80° or less. The cutting tool according to claim 6.

10. The aforementioned cutting edge has a cutting angle of 60° or more and 145° or less relative to the workpiece during cutting. The cutting tool according to claim 9.

Images