Body, cutting tool, and cutting insert

Abstract

To provide a body, cutting tool, and cutting insert suitable for suppressing a decrease in rigidity. [Solution] The cutting tool body 10 is detachably attached by a screw that screws into a screw hole 14 of an insert mounting seat 11 at the axial tip of the cutting tool body 1, wherein, in view of the axial tip, the hole center 14a of the screw hole 14 is located at a different position 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 perpendicular to the first straight line L1 and passing through the body axis center Ax is defined as a second straight line L2, the cutting tool body 10 is located on the opposite side of the second straight line L2 from the position of the cutting edge 21.

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 by 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 to ensure a clearance so that the outer peripheral surface of the body does not contact the inner peripheral surface of the workpiece. 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] A body according to one aspect of the present invention is a cutting tool body to which a cutting insert equipped with a cutting edge is detachably attached by a screw that is screwed into a screw hole in an insert mounting seat at the axial tip, wherein, in view of the axial tip, the center of the screw hole is located at a position different from the axis center of the body.

[0007] In the body structure described above, the center of the screw hole is positioned differently from the center of the body axis. Therefore, when mounting a cutting insert, if we consider a line that runs along the cutting edge and passes through the center of the body axis as the first straight line, it is possible to position the insert on the opposite side of the cutting edge, separated by a second straight line that is perpendicular to the first straight line and also passes through the center of the axis. This allows for a larger surface area of ​​the insert mounting seat on the body, particularly in the area near the cutting edge where cutting resistance is especially high during machining. Consequently, the reduction in the rigidity of the body is suppressed, and vibrations of the cutting insert are reduced during machining, enabling stable cutting.

[0008] The outer circumference of the tip is provided with a chip discharge pocket for guiding and discharging chips generated by cutting, and the center of the screw hole may be positioned on the opposite side of the chip discharge pocket from a first straight line passing through the center of the body axis when viewed from the tip in the axial direction.

[0009] The discharge pocket may have a concave curved surface shape that extends while curving away from the axial tip when viewed from the axial tip (away from the rake face of the cutting insert when a cutting insert is installed).

[0010] The coolant flow path has a discharge port that opens at a concave curved surface, and the flow path cross-section perpendicular to the axial direction may be elliptical or oblong.

[0011] The coolant flow path may have a gradually decreasing cross-sectional area as it approaches the discharge port.

[0012] The coolant supply passage has a larger diameter than the coolant passage, and the coolant passage is in communication with the coolant supply passage. The point where the coolant passage and the coolant supply passage communicate may have a fillet portion that bulges inward in an arc shape when viewed in cross-section along the axial direction.

[0013] A cutting tool according to one aspect of the present invention comprises a body having the above configuration, a cutting insert mounted on an insert mounting seat, and a screw for fastening and fixing the cutting insert to the body, wherein the center of the screw hole is located on the opposite side of the cutting edge's position from the cutting edge's position, with respect to the second straight line, where the first straight line is a line along the cutting edge and passing through the body axis center, and the second straight line is a line perpendicular to the first straight line and passing through the body axis center.

[0014] A cutting insert according to one aspect of the present invention is a cutting insert that is fastened and mounted by a screw that is screwed into a screw hole in an insert mounting seat provided at the axial tip of a body, and has a cutting edge provided on the outer circumference and a hole through which the screw is inserted, wherein the center of the hole is located at a position different from the center of the insert axis, and when a line along the cutting edge and passing through the center of the insert axis is defined as a third straight line, and a line perpendicular to the third straight line and passing through the center of the insert axis is defined as a fourth straight line, the cutting insert is located on the opposite side of the cutting edge with respect to the fourth straight line. The cutting edge may be positioned to protrude from both the outer circumference and the tip. [Effects 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 explanation of the drawing]

[0016] [Figure 1] This is a perspective view showing a cutting tool in one embodiment of the present invention. [Figure 2] This is a side view of a cutting tool, seen from one direction perpendicular to the body axis. [Figure 3] This is a plan view of the cutting tool, perpendicular to the body axis and viewed from the discharge pocket side. [Figure 4]It is a view of the cutting tool seen from the tip side along the center of the body axis. [Figure 5] It is a perspective view of the body. [Figure 6] It is a view of the body seen from the tip side along the center of the body axis. [Figure 7] It is a perspective view showing the internal structure of the body in a transparent state. [Figure 8] It is a view (side view) seen from one direction perpendicular to the center of the body axis showing the internal structure of the body in a transparent state. [Figure 9] It is a view (plan view) seen from a direction perpendicular to the center of the body axis and from the discharge pocket side showing the internal structure of the body in a transparent state. [Figure 10] It is an explanatory drawing for explaining the inner diameter end face grooving process using the cutting tool. [Figure 11] It is an explanatory drawing for explaining the end face grooving process using the cutting tool. [Figure 12] It is an explanatory drawing showing the chip discharge path during cutting with the cutting tool. [Figure 13] It is a view of the cutting tool according to the modification seen from the tip side along the center of the body axis. [Figure 14] It is a view of the body constituting the cutting tool according to the modification seen from the tip side along the center of the body axis.

Embodiments 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 this embodiment consists of a body (sometimes called a holder) 10 and a cutting insert 20 that is attached to an insert mounting seat 11 at the tip 10t of the body 10 using fastening screws 40 (see Figures 1 to 4). In this embodiment, the cutting tool 1 is mainly used for inner diameter end face grooving (see Figure 10) to form an inner diameter end face groove Ni in the workpiece W, or for end face grooving (see Figure 11) to form an end face groove No in the workpiece W, using the cutting edge 21 of the cutting insert 20.

[0019] The cutting tool 1 comprises a body 10 and a cutting insert 20. The cutting insert 20 can be attached to and detached from the insert mounting seat 11 at the tip 10t of the body 10 using a screw 40. This replaceable cutting edge allows the cutting edge (cutting edge) 21 to be replaced by replacing the cutting insert 20 (see Figure 1, etc.).

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

[0021] As shown in Figure 4, the hole center 22a of the hole portion 22 of the cutting insert 20 is located on the opposite side of the cutting edge 21 from the cutting edge 21, with respect to the lines L3 and L4, where L3 (third line) is the line along the cutting edge 21, P31 and P32 are the intersection points of L3 and the outer shape of the cutting insert 21, M1 is the midpoint of P31 and P32, and L4 (fourth line) is the line perpendicular to L3 and passing through M1.

[0022] The cutting insert 20 is mounted on the insert mounting seat 11 of the body 10 by fastening a screw 40, which is passed through the hole 22, to a screw hole 14 formed in the insert mounting seat 11 of the body 10. At this time, the straight lines L3, L4, and midpoint M1 of the cutting insert 20 coincide with the first straight line L1, the second straight line L2, and the body axis center Ax of the body 10, respectively. However, due to mounting errors or other reasons, the straight line L3 of the cutting insert 20 and the first straight line L1 of the body 10 may be slightly misaligned.

[0023] Body 10 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.

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

[0025] The body 10 has an insert mounting seat 11 at its tip 10t in the direction along the body axis center Ax (axial direction) (see Figures 5 and 6). The insert mounting seat 11 has a screw hole 14 along the body axis center Ax for screwing in a fastening screw 40, 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 circumference of its tip portion 10t for guiding and discharging chips generated by cutting (see Figure 1, etc.). By providing the discharge pocket 15 in the body 10 in this way, the efficiency of chip discharge generated by cutting the workpiece W can be improved.

[0027] Furthermore, the discharge pocket 15 has a concave curved surface portion 16. When viewed from the axial end of the body 10, this concave curved surface portion 16 extends while curving away from the rake face 21a of the cutting edge 21 of the cutting insert 20 (see Figures 1 and 2). By providing such a concave curved surface portion 16 in the discharge pocket 15, the chips generated by cutting the workpiece W are smoothly discharged along the concave curved surface portion 16 (in the direction of arrow A in Figure 12) (see Figure 12). This makes it possible to further improve the chip discharge performance generated by cutting the workpiece W.

[0028] The insert mounting seat 11 of the body 10 has a seating surface 12 facing forward of the body axis center Ax (towards where the cutting insert 20 is mounted). The cutting insert 20 has multiple (three in this example) fitting protrusions 23 formed on the surface that abuts against the seating surface 12, and the seating surface 12 of the insert mounting seat 11 has three fitting recesses 13A, 13B, and 13C into which the fitting protrusions 23 of the cutting insert 20 fit (see Figure 6). The fitting protrusions 23 fit into these fitting recesses 13A, 13B, and 13C, thereby positioning the orientation of the cutting insert 20 relative to the insert mounting seat 11 of the body 10 around the body axis center Ax. In other words, the fitting recesses 13A, 13B, and 13C and the fitting protrusion 23 function as positional references around the body axis center Ax when mounting the cutting insert 20 to the body 10, so that the direction of extension of the cutting edge 21 is in the desired direction (horizontal direction in Figure 4) when viewed from the axial tip of the cutting tool 1.

[0029] The fitting recesses 13A, 13B, and 13C formed on the seating surface 12 are formed around the screw hole 14 and are spaced apart in the circumferential direction around the screw hole 14 (see Figure 6). The seating 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. Of the three divided regions 12A, 12B, and 12C, region 12A corresponds to the area near the cutting edge 21 of the cutting insert 20 that is mounted on the insert mounting seat 11.

[0030] The screw hole 14 of the insert mounting seat 11 is positioned such that, when viewed from the axial end of the body 10, the hole center 14a is at a different position from the body axis center Ax of the body 10 (see Figure 6). Furthermore, when viewed from the axial end of the body 10, the hole center 14a of the screw hole 14 is positioned on the opposite side of the second straight line L2 from the cutting edge 21 of the cutting insert 20 mounted on the insert mounting seat 11, with the second straight line L2 being the boundary between the first straight line L1, which is along the cutting edge 21 of the cutting insert 20 and passing through the body axis center Ax, and the second straight line L2, which is perpendicular to the first straight line L1 and passing through the body axis center Ax (see Figure 6). As a result, regions 12A, 12B, and 12C can secure a large area in region 12A, which corresponds to the area near the cutting edge 21 where particularly large cutting resistance is applied during machining (see Figure 6). Therefore, the reduction in rigidity of the body 10 is suppressed, and vibration of the cutting insert 20 is suppressed, enabling stable cutting.

[0031] Furthermore, the hole center 14a of the screw hole 14 is positioned on the opposite side of the discharge pocket 15 from the first straight line L1 when viewed from the axial end (see Figure 6). By positioning 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, the reduction in rigidity of the body 10 is suppressed, and vibration of the cutting insert 20 is suppressed, enabling stable cutting.

[0032] Furthermore, 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 when 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 positioned at a different location from the insert axis center that coincides with the body axis center Ax (see Figure 4). Moreover, the hole center 22a of the hole portion 22 of the cutting insert 20 is positioned on the opposite side of the cutting edge 21 with respect to the second straight line L2 (see Figure 4). This makes it possible to increase the area of ​​the region 12A corresponding to the vicinity of the cutting edge 21, which is subjected to particularly large cutting resistance during machining. Therefore, while miniaturization is achieved, a decrease in the rigidity of the body 10 is suppressed, and vibration of the cutting insert 20 during machining is suppressed, enabling stable cutting.

[0033] The body 10 has a coolant passage 50 (see Figures 7, 8, and 9). The coolant passage 50 is located on the tip 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. The body 10 also has a coolant supply passage 60. The coolant supply passage 60 is formed with a larger diameter than the coolant passage 50 and is located on the base end 10b side of the body 10, opening at the base end 10b. The coolant passage 50 is connected to the tip side of the coolant supply passage 60.

[0034] Coolant is supplied to the body 10 from the machine tool side through a coolant supply passage 60. The coolant supplied to this coolant supply passage 60 is sent through the coolant supply passage 60 to the coolant flow path 50. The coolant sent to the coolant flow path 50 is discharged through the coolant flow path 50 from the discharge port 51 which opens in the concave curved surface portion 16 of the discharge pocket 15 toward the cutting edge 21 of the cutting insert 20. This delivers coolant to the cutting area by the cutting edge 21, enabling smooth chip evacuation and extending the lifespan of the cutting insert 20.

[0035] The discharge port 51 of the coolant flow path 50 has an elliptical flow path cross-section perpendicular to the axial direction of the body 10 (see Figure 4). This elliptical shape has the major axis in the circumferential direction of the body 10 and the minor axis in the radial direction. This increases the amount of coolant discharged from the discharge port 51, further improving chip evacuation and extending the lifespan of the cutting insert 20. Note that the flow path cross-section of the discharge port 51 is not limited to an elliptical shape; it may also be an oblong shape.

[0036] Furthermore, the cross-sectional area of ​​the coolant flow path 50 gradually decreases towards the discharge port 51. This allows the flow velocity of the coolant supplied from the coolant supply passage 60 and flowing through the coolant flow path 50 to increase towards the discharge port 51. Consequently, the chip evacuation efficiency by the coolant discharged from the discharge port 51 is further improved, and the lifespan of the cutting insert 20 can be further extended.

[0037] The coolant passage 50 has a fillet portion 52 at the point where it communicates with the coolant supply passage 60 (see Figures 8 and 9). The fillet portion 52 is formed on the inner edge of the coolant passage 50 that communicates with the coolant supply passage 60, and has a shape that bulges inward in an arc shape when viewed in cross-section along the body axis center Ax. By providing a fillet portion 52 that bulges inward in an arc shape at the point where the coolant passage 50 and the coolant supply passage 60 communicate, the inlet loss at the point of communication when coolant is supplied 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 this embodiment, in the insert mounting seat 11 of the body 10, the area of ​​the seating surface 12 can be made large in the region 12A near the cutting edge 21, where particularly large cutting resistance is applied during machining. As a result, the reduction in rigidity of the body 10 is suppressed, and vibration of the cutting insert 20 is suppressed during machining, enabling stable cutting.

[0039] In this embodiment, the cutting tool 1 is described as a type in which the cutting edge 21 of the cutting insert 20 is positioned on one side of the body 10 when the cutting insert 20 is attached to the insert mounting seat 11 of the body 10. However, it may also be a reversed type in which the cutting edge 21 of the cutting insert 20 is positioned on the other side of the body 10, symmetrically separated by the second straight line L2 (see Figures 13 and 14).

[0040] In this case as well, the screw hole 14 of the insert mounting seat 11 is positioned such that, when viewed from the axial end of the body 10, the hole center 14a is at a different position from the body axis center Ax of the body 10 (see Figure 14). Furthermore, when viewed from the axial end of the body 10, the hole center 14a of the screw hole 14 is positioned on the opposite side of the cutting edge 21 of the cutting insert 20 mounted on the insert mounting seat 11, with respect to the second straight line L2, where the first straight line L1 is a line that runs along the cutting edge 21 of the cutting insert 20 and passes through the body axis center Ax, and the second straight line L2 is a line perpendicular to the first straight line L1 and also passes through the body axis center Ax (see Figure 14).

[0041] As a result, the seating surface 12 has a large area in region 12A, which corresponds to the area near the cutting edge 21 where particularly large cutting resistance is applied during machining (see Figure 14). Therefore, the reduction in rigidity of the body 10 is suppressed, and vibration of the cutting insert 20 is suppressed during machining, enabling stable cutting.

[0042] Furthermore, the hole center 14a of the screw hole 14 is positioned on the opposite side of the discharge pocket 15 from the first straight line L1 when viewed from the axial end (see Figure 14). By positioning 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, and thus enabling stable cutting by suppressing vibration of the cutting insert 20.

[0043] This disclosure is not limited to the above-mentioned specific examples, and any modifications made to these examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the above-mentioned specific examples are not limited to those exemplified and can be modified as appropriate. The elements of each of the above-mentioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise. [Explanation of Symbols]

[0044] 1 cutting tools 10 Body 10t tip 11 Insert mounting seat 14 screw holes 14a Hole center 15 Discharge pockets 16 Concave curved section 20 cutting inserts 21 cutting edge 21a Scoop face 22 Hole 22a Hole center 40 screws 50 Coolant flow path 51 Discharge port 52 Fillet section 60 Coolant supply line L1 1st straight line L2 2nd straight line L3 straight line (3rd straight line) L4 Straight line (4th straight line)

Claims

1. A cutting tool body in which a cutting insert equipped with a cutting edge is detachably attached by a screw that is screwed into a threaded hole in the insert mounting seat at the axial tip, In an axial view of the tip, the center of the screw hole is located at a different position from the center of the body axis. body.

2. The outer circumference of the tip is equipped with an discharge pocket for guiding and discharging chips generated by cutting. The center of the screw hole is located on the opposite side of the chip discharge pocket from the first straight line passing through the center of the body axis, when viewed from the axial end. The body according to claim 1.

3. The discharge pocket has a concave curved surface shape that extends while curving away from the axial tip when viewed from the axial tip. The body according to claim 2.

4. It has a coolant flow path having a discharge port that opens at the aforementioned concave curved surface, The coolant flow path has a cross-sectional shape that is elliptical or oblong, perpendicular to the axial direction. The body according to claim 1.

5. The coolant flow path has a gradually decreasing cross-sectional area toward the discharge port. The body according to claim 4.

6. Having a coolant supply passage with a larger diameter than the aforementioned coolant flow path, The coolant passage is connected to the coolant supply passage, The point of communication between the coolant passage and the coolant supply passage has a fillet portion that bulges inward in an arc shape when viewed in cross-section along the axial direction. The body according to claim 4.

7. The body according to claim 1, A cutting insert mounted on the aforementioned insert mounting seat, A screw for fastening and fixing the cutting insert to the body, Equipped with, The center of the screw hole is located on the opposite side of the cutting edge's position from the cutting edge's position, with respect to the second straight line, when the first straight line is defined as a line along the cutting edge and passing through the body axis center, and the second straight line is defined as a line perpendicular to the first straight line and passing through the body axis center. cutting tools.

8. A cutting insert that is fastened and mounted by a screw that is screwed into a screw hole in an insert mounting seat provided at the axial end of the body, A cutting edge provided on the outer circumference, The hole through which the screw is inserted, It has, The hole center of the aforementioned hole is positioned at a location different from the insert axis center, and when a line along the cutting edge and passing through the insert axis center is defined as a third straight line, and a line perpendicular to the third straight line and passing through the insert axis center is defined as a fourth straight line, the hole is positioned on the opposite side of the cutting edge from the fourth straight line. Cutting insert.

9. The cutting edge is positioned to protrude from both the outer circumference and the tip. The cutting insert according to claim 8.

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