Body, cutting tool, and cutting insert

Abstract

Provided are a body, a cutting tool, and a cutting insert suitable for suppressing a decrease in rigidity. 【Solution means】The body 10 of a cutting tool 1 to which a cutting insert 20 having a cutting edge 21 is detachably attached by a screw screwed into a screw hole 14 of an insert mounting seat 11 at the axial front end portion, wherein, in a front view in the axial direction, the hole center 14a of the screw hole 14 is arranged at a position different from the body axis center Ax, and when a line along the cutting edge 21 and passing through the body axis center Ax is defined as a first straight line L1 and a line orthogonal to the first straight line L1 and passing through the body axis center Ax is defined as a second straight line L2, it is arranged on the side opposite to the arrangement position of the cutting edge 21 with the second straight line L2 as a boundary.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a cutting tool that performs, for example, inner diameter groove machining with a cutting edge provided on a cutting insert fixed to the tip of a body. In this cutting tool, the cutting insert is fixed to the tip of the body by fastening a screw inserted into a hole of the cutting insert into a screw hole formed at the axial center at the tip of the body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The body of a cutting tool used for inner diameter groove machining can also be fitted with a cutting insert for inner diameter end face groove machining or a cutting insert for end face groove machining instead of the cutting insert for inner diameter groove machining. In such a case, there is an advantage that the body can be made common. In inner diameter groove machining, it is necessary to make the diameter of the tip side portion of the body thinner than the diameter of the rear end side portion so that the outer peripheral surface of the body does not contact the inner peripheral surface of the workpiece, in order to ensure a clearance. However, in inner diameter end face groove machining or end face groove machining, it is not necessary to ensure such a clearance, and the common use of the body for inner diameter groove machining has been a factor in reducing the body rigidity.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a body, a cutting tool, and a cutting insert suitable for suppressing a decrease in rigidity.

Means for Solving the Problems

[0006] The body according to one aspect of the present invention is a body of a cutting tool in which a cutting insert having a cutting edge is detachably attached by a screw screwed into a screw hole of an insert mounting seat at the axially front end portion, and in a front view in the axial direction, the center of the screw hole is arranged at a position different from the center of the body axis.

[0007] In the body having the above structure, since the center of the screw hole is arranged at a position different from the center of the body axis, when the cutting insert is mounted, when a line along the cutting edge and passing through the center of the body axis is defined as a first straight line, it is possible to arrange it on the side opposite to the cutting edge with a second straight line orthogonal to the first straight line and passing through the axis center as a boundary. As a result, in the insert mounting seat of the body, the area of the seat surface can be ensured to be large in the region near the cutting edge where a particularly large cutting resistance is applied during cutting. Therefore, a decrease in the rigidity of the body is suppressed, and vibration of the cutting insert during cutting is suppressed, enabling stable cutting.

[0008] The outer periphery at the front end portion may be provided with a discharge pocket for guiding and discharging chips generated by cutting, and the center of the screw hole may be arranged on the side opposite to the chip discharge pocket with a first straight line passing through the center of the body axis as a boundary in a front view in the axial direction.

[0009] The discharge pocket may have a concave curved surface shape portion that extends while curving in a direction away from the axially front end (in the direction away from the rake face of the cutting insert when the cutting insert is mounted) in a front view in the axial direction.

[0010] It may have a coolant flow path having a discharge port that opens at the concave curved surface shape portion, and the cross section of the coolant flow path orthogonal to the axial direction may be an elliptical shape or an oval shape.

[0011] The coolant flow path may be gradually reduced in cross-sectional area toward the discharge port.

[0012] It has a coolant supply path with a larger diameter than the coolant flow path, the coolant flow path is communicated with the coolant supply path, and the communication portion between the coolant flow path and the coolant supply path may have a fillet portion that bulges in an arc shape inward in a cross-sectional view along the axial direction.

[0013] The cutting tool according to one aspect of the present invention includes the body having the above configuration, a cutting insert mounted on the insert mounting seat, and a screw for fastening and fixing the cutting insert to the body. The center of the screw hole is arranged on the side opposite to the arrangement position of the cutting edge with the second straight line as a boundary when a line along the cutting edge and passing through the center of the body axis is defined as the first straight line and a line perpendicular to the first straight line and passing through the center of the body axis is defined as the second straight line.

[0014] The cutting insert according to one aspect of the present invention is a cutting insert that is fastened and mounted by a screw screwed into a screw hole of an insert mounting seat provided at the axially front end portion of the body, and has a cutting edge provided on the outer peripheral side and a hole portion through which the screw is inserted. The center of the hole portion is arranged at a position different from the center of the insert axis, and is arranged on the side opposite to the cutting edge with the fourth straight line as a boundary when a line along the cutting edge and passing through the center of the insert axis is defined as the third straight line and a line perpendicular to the third straight line and passing through the center of the insert axis is defined as the fourth straight line. The cutting edge may be arranged to protrude on the outer peripheral side and the tip side.

Advantages of the Invention

[0015] According to the present invention, a body, a cutting tool, and a cutting insert suitable for suppressing a decrease in rigidity are provided.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

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Figure 8

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Figure 10

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Figure 14

Best Mode for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments of the body, cutting tool, and cutting insert according to the present invention will be described in detail with reference to the drawings (see FIGS. 1 to 12).

[0018] The cutting tool 1 of the present embodiment is composed of a body (which may be called a holder) 10 and a cutting insert 20 attached to an insert mounting seat 11 at the tip 10t of the body 10 using a fastening screw 40 (see FIGS. 1 to 4). In the present embodiment, the cutting tool 1 is mainly used for an inner diameter end face groove machining (see FIG. 10) for forming an inner diameter end face groove Ni in the workpiece W or an end face groove machining (see FIG. 11) for forming an end face groove No in the workpiece W by the cutting edge 21 of the cutting insert 20.

[0019] The cutting tool 1 includes a body 10 and a cutting insert 20, and is a cutting tool with an exchangeable cutting edge structure in which the cutting insert 20 can be attached and detached to and from an insert mounting seat 11 at the tip 10t of the body 10 using a screw 40, and the cutting edge (cutting tip) 21 can be exchanged by replacing the cutting insert 20 (see FIG. 1 etc.).

[0020] The cutting insert 20 has a cutting edge 21 provided on the outer peripheral side and protruding toward the tip side, and a hole portion 22 through which the screw 40 is inserted. Note that the tip side where the cutting edge 21 protrudes is the tip side in a direction parallel or substantially parallel to the central axis of the hole portion 22, and can also be referred to as the tip side in the axial direction of the cutting tool 1 that coincides with the body axis center Ax.

[0021] As shown in FIG. 4, the hole center 22a of the hole portion 22 of the cutting insert 20 is arranged on the side opposite to the position of the cutting edge 21 with the straight line L3 (third straight line), which is a line along the cutting edge 21, the intersection points P31 and P32 of the straight line L3 and the outer shape of the cutting insert 21, the midpoint M1 of the intersection points P31 and P32, and the straight line L4 (fourth straight line), which is orthogonal to the straight line L3 and passes through the midpoint M1, as boundaries.

[0022] The cutting insert 20 is attached to the insert mounting seat 11 of the body 10 by fastening a screw 40 passed through the hole portion 22 into a screw hole 14 formed in the insert mounting seat 11 of the body 10. At this time, the straight line L3, the straight line L4, and the midpoint M1 of the cutting insert 20 respectively coincide with the first straight line L1, the second straight line L2, and the body axis center Ax of the body 10. However, due to reasons such as mounting errors, the straight line L3 of the cutting insert 20 may deviate slightly from the first straight line L1 of the body 10.

[0023] The body 10 is formed, for example, by a metal powder sintering 3D printer that three-dimensionally forms a shaped object using metal powder. Examples of the shaping method by the metal powder sintering 3D printer include powder bed fusion, electron beam melting (EBM) that melts powder using an electron beam, or selective laser melting (SLM) that melts powder using a laser beam.

[0024] The body 10 has a shape extending along the body axis center Ax. The body 10 is formed in a columnar shape with a substantially circular cross-sectional shape perpendicular to the body axis center Ax, and a notch portion 10a that functions as a position reference around the body axis center Ax when held by a machine tool is formed at the base end portion 10b of the body 10 (see FIG. 1 etc.).

[0025] The body 10 has an insert mounting seat 11 at the tip portion 10t in the direction along the body axis center Ax (axis direction) (see FIGS. 5 and 6). A screw hole 14 for screwing a fastening screw 40 is provided along the body axis center Ax in this insert mounting seat 11, and the cutting insert 20 can be attached and detached using the screw 40.

[0026] The body 10 has a discharge pocket 15 on the outer peripheral portion at the tip 10t for guiding and discharging chips generated by cutting (see Fig. 1 etc.). By providing the discharge pocket 15 in the body 10 in this way, the discharge property of chips generated by cutting the workpiece W can be improved.

[0027] Also, the discharge pocket 15 has a concave curved surface portion 16. This concave curved surface portion 16 extends while curving in a direction away from the rake face 21a of the cutting edge 21 of the cutting insert 20 when viewed from the tip in the axial direction of the body 10 (see Fig. 1 and Fig. 2). By providing such a concave curved surface portion 16 in the discharge pocket 15, chips generated by cutting the workpiece W are smoothly discharged along the concave curved surface portion 16 (in the direction of arrow A in Fig. 12) (see Fig. 12). Thereby, the discharge property of chips generated by cutting the workpiece W can be further improved.

[0028] The insert mounting seat 11 of the body 10 has a seat surface 12 facing forward (the side where the cutting insert 20 is mounted) of the body axis center Ax. On the surface of the cutting insert 20 that abuts against the seat surface 12, a plurality (three in this example) of fitting convex portions 23 are formed, and the seat surface 12 of the insert mounting seat 11 has three fitting concave portions 13A, 13B, 13C into which the fitting convex portions 23 of the cutting insert 20 are respectively fitted (see Fig. 6). When the fitting convex portions 23 are fitted into these fitting concave portions 13A, 13B, 13C, the orientation of the cutting insert 20 around the body axis center Ax with respect to the insert mounting seat 11 of the body 10 is positioned. That is, the fitting concave portions 13A, 13B, 13C and the fitting convex portions 23 function as a position reference around the body axis center Ax when mounting the cutting insert 20 on the body 10 so that the extending direction of the cutting edge 21 becomes a desired direction (horizontal direction in Fig. 4) when viewed from the tip in the axial direction of the cutting tool 1.

[0029] The fitting recesses 13A, 13B, and 13C formed in the seat surface 12 are formed around the screw hole 14 and are provided at intervals in the circumferential direction around the screw hole 14 (see Fig. 6). And the seat surface 12 of the insert mounting seat 11 is divided into three regions 12A, 12B, and 12C by the fitting recesses 13A, 13B, and 13C. Among the three divided regions 12A, 12B, and 12C, the region 12A is a region corresponding to the vicinity of the cutting edge 21 of the cutting insert 20 mounted on the insert mounting seat 11.

[0030] The screw hole 14 of the insert mounting seat 11 is arranged such that the hole center 14a is at a position different from the body axis center Ax of the body 10 when viewed from the tip in the axial direction of the body 10 (see Fig. 6). Also, when viewed from the tip in the axial direction of the body 10, with the line along the cutting edge 21 of the cutting insert 20 and passing through the body axis center Ax as the first straight line L1, and the line orthogonal to the first straight line L1 and passing through the body axis center Ax as the second straight line L2, the hole center 14a of the screw hole 14 is arranged on the side opposite to the cutting edge 21 of the cutting insert 20 mounted on the insert mounting seat 11 with the second straight line L2 as the boundary (see Fig. 6). Thereby, the regions 12A, 12B, and 12C can secure a large area in the region 12A corresponding to the vicinity of the cutting edge 21 where a particularly large cutting resistance is applied during cutting (see Fig. 6). Therefore, a decrease in the rigidity of the body 10 is suppressed, vibration of the cutting insert 20 is suppressed, and stable cutting becomes possible.

[0031] Furthermore, the hole center 14a of the screw hole 14 is arranged on the side opposite to the discharge pocket 15 with the first straight line L1 as the boundary when viewed from the tip in the axial direction (see Fig. 6). By arranging the hole center 14a of the screw hole 14 in this way, a sufficient area of the region 12B on the discharge pocket 15 side is secured, a decrease in the rigidity of the body 10 is suppressed, vibration of the cutting insert 20 is suppressed, and stable cutting becomes possible.

[0032] In addition, as described above, the cutting insert 20 mounted on the insert mounting seat 11 of the body 10 has an insert axis center that coincides with the body axis center Ax in the state of being mounted on the insert mounting seat 11 of the body 10, and the hole center 22a of the hole portion 22 through which the screw 40 is inserted is arranged at a position different from the insert axis center that coincides with the body axis center Ax (see Fig. 4). Further, in the cutting insert 20, the hole center 22a of the hole portion 22 is arranged on the side opposite to the cutting edge 21 with the second straight line L2 as the boundary (see Fig. 4). Thereby, the area of the region 12A corresponding to the vicinity portion of the cutting edge 21 to which a particularly large cutting resistance is applied during cutting can be increased. Therefore, while achieving miniaturization, a decrease in the rigidity of the body 10 is suppressed, vibration of the cutting insert 20 during cutting is suppressed, and stable cutting is possible.

[0033] The body 10 has a coolant passage 50 (see Figs. 7, 8, and 9). The coolant passage 50 is provided on the tip end portion 10t side of the body 10 and has a discharge port 51 that opens at the concave curved surface portion 16 of the discharge pocket 15. Further, the body 10 has a coolant supply passage 60. The coolant supply passage 60 is formed to have a larger diameter than the coolant passage 50, is provided on the base end portion 10b side of the body 10, and opens at the base end portion 10b. The coolant passage 50 is communicated with the tip end side of the coolant supply passage 60.

[0034] Coolant is supplied to the coolant supply passage 60 of the body 10 from the machine tool side. The coolant supplied to this coolant supply passage 60 is sent into the coolant passage 50 through the coolant supply passage 60. The coolant sent into the coolant passage 50 is discharged from the discharge port 51 that opens at the concave curved surface portion 16 of the discharge pocket 15 through the coolant passage 50 toward the cutting edge 21 of the cutting insert 20. Thereby, coolant can be sent to the cutting portion by the cutting edge 21, and while obtaining smooth chip discharge performance, the long life of the cutting insert 20 can be achieved.

[0035] The discharge port 51 of the coolant passage 50 has an elliptical cross-sectional shape perpendicular to the axial direction of the body 10 (see Fig. 4). This elliptical shape has its major axis in the circumferential direction of the body 10 and its minor axis in the radial direction. This can increase the amount of coolant discharged from the discharge port 51, enhance the dischargeability of chips, and further extend the service life of the cutting insert 20. Note that the cross-sectional shape of the discharge port 51 is not limited to an elliptical shape and may be an oval shape.

[0036] Also, the coolant passage 50 is gradually reduced in cross-sectional area toward the discharge port 51. This can increase the flow velocity of the coolant fed from the coolant supply passage 60 and flowing through the coolant passage 50 toward the discharge port 51. Therefore, the dischargeability of chips by the coolant discharged from the discharge port 51 can be further enhanced, and the service life of the cutting insert 20 can be further extended.

[0037] The coolant passage 50 has a fillet portion 52 at the communication portion with the coolant supply passage 60 (see Figs. 8 and 9). The fillet portion 52 is formed at the inner edge portion of the coolant passage 50 communicating with the coolant supply passage 60 and has a shape that bulges in an arc shape inward in a cross-sectional view along the body axis center Ax. In this way, by providing the fillet portion 52 that bulges in an arc shape inward at the communication portion between the coolant passage 50 and the coolant supply passage 60, the inlet loss at the communication portion when the coolant is fed from the coolant supply passage 60 to the coolant passage 50 can be suppressed by the fillet portion 52.

[0038] As described above, according to the present embodiment, in the insert mounting seat 11 of the body 10, the area of the seat surface 12 can be ensured to be large in the region 12A near the cutting edge 21 where particularly large cutting resistance is applied during cutting. Therefore, a decrease in the rigidity of the body 10 is suppressed, vibration of the cutting insert 20 during cutting is suppressed, and stable cutting becomes possible.

[0039] Note that, as the cutting tool 1 according to the present embodiment, when the cutting insert 20 is attached to the insert mounting seat 11 of the body 10, the type in which the cutting edge 21 of the cutting insert 20 is disposed on one side of the body 10 has been described as an example. However, it may be a type with a reverse arrangement in which the cutting edge 21 of the cutting insert 20 is disposed on the other side of the body 10 and is line-symmetric with respect to the second straight line L2 (see FIGS. 13 and 14).

[0040] Also in this case, the screw hole 14 of the insert mounting seat 11 is arranged such that the hole center 14a is at a position different from the body axis center Ax of the body 10 when viewed from the tip in the axial direction of the body 10 (see FIG. 14). And when viewed from the tip in the axial direction of the body 10, the hole center 14a of the screw hole 14 is along the cutting edge 21 of the cutting insert 20 and when the line passing through the body axis center Ax is defined as the first straight line L1 and the line orthogonal to the first straight line L1 and passing through the body axis center Ax is defined as the second straight line L2, it is arranged on the side opposite to the cutting edge 21 of the cutting insert 20 mounted on the insert mounting seat 11 with the second straight line L2 as a boundary (see FIG. 14).

[0041] Thereby, the regions 12A, 12B, 12C of the seat surface 12 can secure a large area in the region 12A corresponding to the vicinity of the cutting edge 21 to which a particularly large cutting resistance is applied during cutting (see FIG. 14). Therefore, a decrease in the rigidity of the body 10 is suppressed, and vibration of the cutting insert 20 during cutting is suppressed, enabling stable cutting.

[0042] Furthermore, the hole center 14a of the screw hole 14 is arranged on the side opposite to the discharge pocket 15 with the first straight line L1 as a boundary when viewed from the tip in the axial direction (see FIG. 14). By arranging the hole center 14a of the screw hole 14 in this way, the area of the region 12B on the discharge pocket 15 side is sufficiently secured, suppressing a decrease in the rigidity of the body 10, so that vibration of the cutting insert 20 is suppressed and stable cutting is possible.

[0043] Note that the present disclosure is not limited to the above specific examples, and those obtained by appropriately modifying the design by those skilled in the art to these specific examples are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the above-described specific examples, and its arrangement, conditions, shape, etc. are not limited to those illustrated and can be appropriately changed. Each element included in each of the above-described specific examples can be appropriately changed in combination as long as no technical contradiction occurs.

Explanation of Signs

[0044] 1 Cutting tool 10 Body 10t Tip 11 Insert mounting seat 14 Thread hole 14a Hole center 15 Discharge pocket 16 Concave curved surface portion 20 Cutting insert 21 Cutting edge 21a Rake face 22 Hole portion 22a Hole center 40 Screw 50 Coolant flow path 51 Discharge port 52 Fillet portion 60 Coolant supply path L1 First straight line L2 Second straight line L3 Straight line (third straight line) L4 Straight line (fourth straight line)

Claims

1. A cutting tool body in which a cutting insert having a cutting edge is detachably attached by a screw that is screwed into a single screw hole formed in an insert mounting seat at a tip end in an axial direction, When viewed from the tip in the axial direction, the hole center of the screw hole is disposed at a position different from the body axial center, A discharge pocket is provided on the outer periphery of the tip portion to guide and discharge chips generated by cutting, a hole center of the screw hole is disposed on an opposite side to the discharge pocket with respect to a first straight line passing through the body axial center, when viewed from the tip end in the axial direction; The discharge pocket has a concave curved surface portion at a part of the axial tip side, the concave curved surface portion extending while curving in a direction away from the axial tip. body.

2. a coolant flow passage having a discharge port that opens at the concave curved surface portion; The coolant flow passage has a flow passage cross section perpendicular to the axial direction, the flow passage cross section being elliptical or oval. The body of claim 1 .

3. The coolant flow passage has a flow passage cross-sectional area gradually decreasing toward the discharge port. The body of claim 2.

4. A coolant supply passage having a diameter larger than that of the coolant passage, The coolant flow path is connected to the coolant supply path, A communication portion between the coolant flow passage and the coolant supply passage has a fillet portion that bulges inward in an arc shape in a cross-sectional view along the axial direction. The body of claim 2.

5. A body according to claim 1; A cutting insert attached to the insert mounting seat; A screw for fastening and fixing the cutting insert to the body; Equipped with When a line along the cutting edge and passing through the body axis center is defined as a first straight line, and a line perpendicular to the first straight line and passing through the body axis center is defined as a second straight line, the hole center of the screw hole is disposed on the opposite side of the second straight line from the position where the cutting edge is disposed. cutting tools.

6. A cutting insert having a cutting edge provided on an outer periphery side; A body to which the cutting insert is attached; A cutting tool comprising: the body has an outer periphery at a tip end portion, the outer periphery being located on a base end side with respect to a rake face of the cutting insert in an axial direction, the pocket being for guiding and discharging chips generated by cutting; the cutting insert has a hole through which a screw is inserted, and is fastened to the body by a screw that is screwed into a single threaded hole formed in an insert mounting seat at an axial tip of the body; When a line along the cutting edge and passing through the center of the body axis is defined as a first straight line, and a line perpendicular to the first straight line and passing through the center of the body axis is defined as a second straight line, the center of the screw hole is located on the opposite side of the second straight line to the position where the cutting edge is disposed and on the opposite side of the discharge pocket to the first straight line. cutting tools.

7. In the cutting insert, the cutting edge is disposed so as to protrude toward the outer periphery and the tip side.

7. The cutting tool according to claim 6.

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