Cutting tools

Abstract

To provide a cutting tool which enables improvement of discharge ability of chips and can inhibit wear of the tool.SOLUTION: A cutting tool can supply a coolant to a blade edge. A tool body having a length in one direction has: a coolant passage extending in a longitudinal direction; a discharge port communicating with a tip of the coolant passage; and a groove part communicating with the tip of the coolant passage through the discharge port. The groove part is formed having a width larger than a diameter of the discharge port.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] When cutting, chips are generated, and if these chips get tangled in the cutting insert, the cutting edge can be damaged. To prevent this, it is common to supply cutting oil (hereinafter referred to as coolant) to the cutting point during cutting to improve the lubrication and cutting ability of the cutting insert against the workpiece.

[0003] However, when coolant is supplied during cutting, it is difficult to completely remove chips because the coolant supply pressure is low and it is difficult to apply the coolant directly to the cutting point.

[0004] Therefore, in recent years, there has been an increase in internal coolant supply tool holders that allow coolant to pass through the tool holder and be supplied directly to the cutting point.In addition, there has been an increase in the use of high-pressure coolant pumps to increase the coolant supply pressure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 139401 [Patent Document 2] Republished WO2015 / 056496 Summary of the Invention [Problem to be solved by the invention]

[0006] The above-mentioned Patent Document 1 discloses an internal coolant supply type tool holder for external diameter machining. Patent Document 2 discloses an internal coolant supply type tool holder for internal diameter machining, which includes a cylindrical guide sleeve. However, in the case of such internal coolant supply type tool holders for internal diameter machining, for example, the coolant sprayed from the guide sleeve comes into contact with other components before reaching the cutting edge, resulting in a decrease in coolant supply pressure. Furthermore, since the coolant outlet cannot be located near the cutting edge, it is difficult to supply high-pressure coolant to the internal diameter machining point. Furthermore, turbulence within the guide sleeve is likely to cause pressure loss, making it difficult to spray coolant at high pressure. For these reasons, it is not possible to supply sufficient coolant to the cutting edge of the cutting insert, which causes problems such as chip entanglement and tool wear.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide a tool holder that can improve chip discharge performance and reduce tool friction. [Means for solving the problem]

[0008] In order to solve the above problems, one form of cutting tool of the present invention is a cutting tool capable of supplying coolant toward a cutting edge, wherein a tool body having a length in one direction has a coolant flow passage extending in the longitudinal direction, an outlet communicating with the tip of the coolant flow passage, and a groove portion communicating with the tip of the coolant flow passage via the outlet, and the groove portion is formed with a width larger than the diameter of the outlet.

[0009] Also, a cutting tool capable of supplying coolant toward the cutting edge may be configured such that the tool body has an attachment portion that is located at the tip of the tool body closer to the groove portion and to which a cutting edge can be attached, and the groove portion is formed with a width larger than the diameter of the outlet.

[0010] The central axis of the coolant flow passage may be radially offset from the central axis of the tool body, and the cutting edge may be positioned on an extension of the central axis of the coolant flow passage.

[0011] The coolant flow path may have at least a first flow path and a second flow path arranged in order from the tip side, and the central axes of the first flow path, the discharge port, and the groove portion may be coaxial with each other.

[0012] The tool may also be configured to include a flow path forming member that is inserted inside the tool body, the flow path forming member having a second through hole whose tip communicates with the discharge port and forms at least a part of the coolant flow path.

[0013] The groove may be formed on a surface of the outer peripheral surface of the tool body that faces in the same direction as the flank of the cutting edge.

[0014] The groove may be formed on a surface of the outer peripheral surface of the tool body that faces in the same direction as the rake face of the cutting edge.

[0015] The base end side of the coolant flow passage may be positioned more inward of the tool body than the tip end side.

[0016] The groove may be tapered so that its width increases from the base end on the discharge port side to the tip end. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a tool holder that can improve chip discharge performance and reduce tool friction. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing the configuration of a cutting tool according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the configuration of the main body in the first embodiment. [Figure 3] FIG. 3 is a top view of the main body. [Figure 4] FIG. 4 is a side view of the main body. [Figure 5] 5 is a cross-sectional view of the main body portion taken along line VV of FIG. [Figure 6] FIG. 6 is a view of the main body as seen from the axial tip end side. [Figure 7] FIG. 7 is a perspective view showing the overall configuration of the flow path forming member. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII shown in FIG. [Figure 9] FIG. 9 is a view of the flow path forming member as seen from the tip end side. [Figure 10] FIG. 10 is a perspective view showing the overall configuration of the cutting insert detachably attached to the tool body in the first embodiment. [Figure 11] FIG. 11 is a top view showing the cutting tool (in a state where the cutting insert is attached to the tool body). [Figure 12] FIG. 12 is a right side view showing the cutting tool. [Figure 13] FIG. 13 is a bottom view showing the cutting tool. [Figure 14] FIG. 14 is a left side view showing the cutting tool. [Figure 15] FIG. 15 is a partially enlarged view showing the cutting insert shown in FIG. 11 and the surrounding structure. [Figure 16] FIG. 16 is a view of the cutting tool as seen from the tip side. [Figure 17] FIG. 17 is a view of the cutting tool as seen from the rear end side. [Figure 18] FIG. 18 is a graph showing the relationship between the diameter of the discharge port in the cutting tool and the discharge pressure of the coolant. [Figure 19A] FIG. 19A is a diagram showing the flow state of the coolant when the discharge port is coaxial with the central axis of the flow path forming through hole. [Figure 19B]FIG. 19B is an enlarged view showing the flow state of the coolant near the discharge port shown in FIG. 19A. [Figure 20A] FIG. 20A is a diagram showing the flow state of the coolant in a configuration in which the discharge port is radially shifted from the central axis of the flow path forming through hole. [Figure 20B] FIG. 20B is an enlarged view showing the coolant flow state near the discharge port shown in FIG. 20A. [Figure 21] FIG. 21 is a perspective view showing the overall configuration of a cutting tool according to the second embodiment. [Figure 22] FIG. 22 is a cross-sectional view taken along line XXII-XXII in FIG. [Figure 23] FIG. 23 is a perspective view showing the overall configuration of a cutting tool according to a third embodiment. [Figure 24] FIG. 24 is a cross-sectional view taken along line XXIV-XXIV in FIG. [Figure 25] FIG. 25 is a perspective view showing the overall configuration of a cutting tool according to a fourth embodiment. [Figure 26] FIG. 26 is a cross-sectional view taken along line XXVI-XXVI in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, several embodiments of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions will be designated by the same reference numerals. Duplicate descriptions of those components may be omitted.

[0020] First Embodiment "Cutting tools" A cutting tool 100 according to a first embodiment of the present invention will be described. FIG. 1 is a perspective view showing the configuration of a cutting tool 100 according to the first embodiment. As shown in Fig. 1, a cutting tool 100 of this embodiment is used for cutting work such as internal machining of a blind hole or the like in a workpiece W. The cutting tool 100 is detachably attached to a machine tool such as an NC lathe (not shown). The cutting tool 100 of this embodiment is an internally oiled tool for internal machining, and supplies coolant toward the cutting edge.

[0021] The cutting tool 100 of this embodiment is an indexable cutting tool and includes a tool body 10 and a cutting insert 1 that is detachably attached to the tool body 10. The cutting tool 100 has a length in one direction, and is inserted, fitted, and fixed in a machine tool (not shown) with the tool center axis P as the center.

[0022] In each figure, in this embodiment, the direction in which the tool center axis P of the tool body 10 extends is referred to as the tool axis direction. In the XYZ Cartesian coordinate system shown in each figure, the tool axis direction corresponds to the X axis. In the tool axis direction, the +X side is referred to as the tip side, and the -X side is referred to as the base side. Furthermore, among the directions (radial directions) perpendicular to the tool center axis P (X direction), the Y direction is referred to as the width direction of the tool body 10. The Z direction perpendicular to the tool center axis P (X direction) and the width direction (Y direction) is referred to as the up-down direction of the tool body 10. The insert center axis CO of the cutting insert 1 extends along the up-down direction of the tool body 10.

[0023] [Tool body] As shown in FIG. 1, the tool body 10 has a substantially cylindrical body portion 10A and a flow passage forming member 10B inserted inside the body portion 10A.

[0024] (Main body) Fig. 2 is a perspective view showing the configuration of the main body 10A in the first embodiment. Fig. 3 is a top view of the main body 10A. Fig. 4 is a side view of the main body 10A. Fig. 5 is a cross-sectional view of the main body 10A taken along line VV shown in Fig. 1. Fig. 6 is a view of the main body 10A as seen from the axial tip side.

[0025] 2 to 5, the main body 10A has, on its outer periphery, an upper surface 10a facing the +Z direction, a lower surface 10b facing the -Z direction, and a right side surface 10c facing the -Y direction, all of which extend parallel to the tool central axis P. The upper surface 10a, the lower surface 10b, and the right side surface 10c are surfaces that form reference surfaces when fixing the cutting tool 100 to a machine tool, and are formed so as to position the cutting tool 100 in the circumferential direction.

[0026] The tip side of main body 10A in the tool axis direction is formed with a first notch 12 recessed downward in the -Z direction from top surface 10a, and a second notch 13 recessed leftward in the +Y direction from right side surface 10c. Notch portions 12 and 13 are formed in an area extending approximately one-third from the tip in the tool axis direction (X direction), and each has, at its bottom, a notch surface 12a that is parallel to the tool axis direction and faces the +Z direction, and a notch surface 13c that faces the -Y direction.

[0027] The cutout surface 12a is located radially inward (toward the -Z side) of the top surface 10a, which is part of the outer circumferential surface, and closer to the top surface 10a than the tool center axis P. An inclined surface 12b connecting the cutout surface 12a and the top surface 10a is formed on the base end side of the cutout portion 12. The inclined surface 12b is inclined so that it approaches the top surface 10a as it approaches the base end side in the axial direction.

[0028] The cutout surface 13c is located radially inward (on the +Y side) of the right side surface 10c, which is part of the outer peripheral surface, and closer to the right side surface 10c than the tool center axis P. An inclined surface 13b connecting the cutout surface 13c and the right side surface 10c is formed on the base end side of the cutout portion 13. The inclined surface 13b is inclined so that it approaches the right side surface 10c as it approaches the base end side in the axial direction. The inclined surface 13b is located closer to the base end than the inclined surface 12b, and the tip of the inclined surface 13b coincides with the base end position of the inclined surface 12b in the tool axial direction.

[0029] A chip pocket (attachment portion) 14 that opens onto the cutout surface 12a is formed on the tip side of the main body 10A in the tool axial direction. The chip pocket 14 is a portion in which a cutting insert 1 (FIG. 1) that is detachably attached to the tool body 10 (main body 10A) is placed. The chip pocket 14 has a concave shape that is recessed downward in the -Z direction from the cutout surface 12a. The chip pocket 14 not only opens onto the cutout surface 12a, but also onto the cutout surface 13c and the tip surface 10d.

[0030] 10 and 15, the chip pocket 14 has a bottom constraint surface 14a that constraints the seating surface 3 (FIG. 10) of the cutting insert 1, which will be described later, a side constraint surface 14b that constraints the long side surface 4a (FIG. 10) of the cutting insert 1, and an inclined constraint surface 14c that constraints the inclined surface 4c (FIG. 10) of the cutting insert 1. As shown in FIG. 3, the side constraint surface 14b is parallel to the tool center axis P. As shown in FIG. 3, the inclined constraint surface 14c is formed on the rear end side of half the axial length of the chip pocket 14, and is inclined in a direction approaching the side constraint surface 14b as it moves from the front end side to the rear end side.

[0031] The cutting insert 1 is attached to the tool body 10 (body portion 10A) by a mounting screw (not shown) that is threaded into a screw hole 15 that penetrates from the bottom restraint surface 14a to the lower surface 10b. The screw hole 15 extends in a direction substantially perpendicular to the tool central axis P.

[0032] As shown in FIG. 2, the tool body 10 of this embodiment has a coolant flow path 7 extending in the longitudinal direction (tool axis direction: X direction), a discharge opening (discharge port) 8 communicating with the tip of the coolant flow path 7, and a groove portion 9 communicating with the tip of the coolant flow path 7 via the discharge opening 8. The main body 10A is formed with a flow path forming through hole 16 that penetrates in the tool axial direction. The flow path forming through hole 16 is for forming the coolant flow path 7 and is composed of a plurality of through holes with different diameters. In this embodiment, the flow path forming through hole 16 has three through holes with different diameters: a first through hole (first flow path) 16A, a second through hole 16B, and a third through hole (second flow path) 16C.

[0033] As shown in FIG. 2, these through holes 16A, 16B, and 16C are arranged in this order from the tip side in the axial direction, and the diameter increases as going toward the base end side. That is, the respective diameters D1, D2, and D3 of the through holes 16A, 16B, and 16C satisfy the relationship D1 < D2 < D3. Note that the diameter D3 of the through hole 16C is the diameter on the tip (through hole 16B) side.

[0034] Here, the diameters of the through holes 16A and 16B are constant in the axial direction. On the other hand, the through hole 16C located on the most base end side of the main body portion 10A has a tapered shape that expands in diameter from the tip (through hole 16B) side toward the base end, and opens to the base end surface of the main body portion 10A. A screw portion 16d is formed inside the through hole 16C, and a joint of the coolant supply hose is attached. Coolant is supplied into the tool main body 10 at a predetermined pressure from the coolant supply hose connected via such a joint.

[0035] Also, the axial lengths L1, L2, and L3 of the through holes 16A, 16B, and 16C satisfy the relationship L2 < L3 < L1, and the axial length L1 of the through hole 16A with the smallest diameter is the longest.

[0036] These through holes 16A, 16B, and 16C are formed coaxially with each other. The central axis O of such a flow path forming through hole 16 is parallel to the tool central axis P and is displaced in the radial direction (-Y direction) with respect to the tool central axis P.

[0037] Note that the present invention is not limited to the configuration of this embodiment. The central axis O of the flow path forming through hole 16 may be inclined at a predetermined angle with respect to the tool central axis P, or at least one of the through holes 16A, 16B, and 16C may not be coaxial.

[0038] A nozzle hole 17 having a diameter smaller than the diameter of the through hole 16A is formed on the tip side of the flow path forming through hole 16. The base end side of the nozzle hole 17 opens into the tip surface of the through hole 16A and communicates with the tip side of the flow path forming through hole 16. On the other hand, the tip side of the nozzle hole 17 opens into the inclined surface 13b. The nozzle hole 17 has a predetermined length in the axial direction. The nozzle hole 17 in this embodiment is formed with a constant diameter in the axial direction and is coaxial with the flow path forming through hole 16.

[0039] A groove 9 that communicates with the tip of the flow-path forming through-hole 16 via a nozzle hole 17 is formed in the cutout surface 13c facing the right side (-Y direction) of the main body 10A. That is, the groove 9 is formed on the surface (the cutout surface 13c) that faces the same direction as the flank of the cutting insert 1. The groove 9 is a groove that recesses from the cutout surface 13c to the left (+Y direction), and its tip side reaches the chip pocket 14. The width of the groove 9 in the Z direction is approximately equal to the diameter of the nozzle hole 17. The central axis of the groove 9 coincides with the central axes of the nozzle hole 17 and the flow-path forming through-hole 16.

[0040] The main body 10A of this embodiment is made of, for example, steel.

[0041] (flow path forming member) Fig. 7 is a perspective view showing the overall configuration of the flow path forming member 10B. Fig. 8 is a cross-sectional view taken along line VIII-VIII shown in Fig. 7. Fig. 9 is a view of the flow path forming member 10B as seen from the tip side. The flow path forming member 10B is incorporated inside the main body 10A. The flow path forming member 10B is inserted into the tip side of the flow path forming through hole 16 formed inside the main body 10A, i.e., into the first through hole 16A.

[0042] The flow path forming member 10B is a cylindrical body formed with a constant diameter in the axial direction except for the tip. The tip of the flow path forming member 10B is tapered, with the diameter decreasing toward the tip side (+X direction). The tip has a circular tip surface 10Ba and a tapered surface 10Bb that is radially outward of the tip surface 10Ba and has an annular shape when viewed from the axial tip side.

[0043] Meanwhile, an annular recess 21 is formed at the rear end of the flow path forming member 10B, recessed radially from the outer circumferential surface. The annular recess 21 is located slightly axially away from the rear end of the flow path forming member 10B toward the tip end, and is formed with a constant depth and width in the circumferential direction. An adhesive is applied to the inside of this annular recess 21 to fix the flow path forming member 10B to the main body 10A.

[0044] The axial length L10B of the flow path forming member 10B is equal to the axial length L1 of the first through hole 16A of the flow path forming through holes 16. That is, in the axial direction, the leading end surface 10Ba of the flow path forming member 10B is aligned with the position of the leading end surface 16a (FIG. 5) of the flow path forming through hole 16 (first through hole 16A) in the main body portion 10A described above, and abuts against this leading end surface 16a. On the other hand, it is preferable that the rear end surface of the flow path forming member 10B is aligned with the position of the leading end surface 16b of the second through hole 16B located in the middle of the flow path forming through hole 16, and does not protrude into the second through hole 16B.

[0045] As shown in FIG. 8 , the flow path forming member 10B has a flow path forming through hole 19 on the inside. The flow path forming through hole 19 constitutes a part of the coolant flow path 7 of this embodiment. The flow path forming through hole 19 of this embodiment has a through hole 19A formed with a constant diameter in the axial direction, a tapered hole 19B communicating with the tip side of the through hole 19A, and a discharge hole 19C communicating with the tip side of the tapered hole 19B. The through hole 19A, the tapered hole 19B, and the discharge hole 19C are coaxial. The diameter of the discharge hole 19C is smaller than the diameter of the through hole 19A and is constant in the axial direction. In this embodiment, the diameter of the discharge hole 19C is preferably, for example, 1.0 mm or less.

[0046] When the flow path forming member 10B is inserted into the main body 10A, the position of the tip (discharge outlet 19d) of the discharge hole 19C coincides with the position of the base end of the nozzle hole 17 of the main body 10A described above. In this embodiment, the diameter of the discharge hole 19C (discharge outlet 19d) is smaller than the diameter of the nozzle hole 17 of the main body 10A, and therefore the discharge outlet 19d of the flow path forming member 10B is exposed inside the nozzle hole 17 when viewed from the axial tip side as shown in FIG.

[0047] That is, since the diameter of the nozzle hole 17 of the main body 10A is larger than that of the discharge hole 19C (discharge port 19d) of the flow path forming member 10B, the coolant discharged from the discharge hole 19C (discharge port 19d) is less likely to come into contact with the inner circumferential surface of the nozzle hole 17, and a decrease in the discharge speed is suppressed. The diameter of the discharge port 19d is smaller than that of the base-end opening 19e and is smaller than the width of the groove 9 formed in the main body 10A.

[0048] The tool body 10 is formed by fixing such a flow passage forming member 10B inside the body portion 10A. A joint for a coolant supply hose is connected to the base end of the tool body 10, and the coolant flow path 7 formed within the tool body 10 has, in order from the base end, the second through hole 16B of the main body 10A, the flow path forming through hole 19 of the flow path forming member 10B, and the discharge opening 8 of the main body 10A. The central axis O of the coolant flow path 7 extends in the longitudinal direction parallel to the tool central axis P as described above, and coincides with the cutting edge of the cutting insert 1.

[0049] The flow path forming member 10B of this embodiment is made of, for example, the same steel material as the main body portion 10A.

[0050] [Cutting insert] Fig. 10 is a perspective view showing the overall configuration of the cutting insert 1 detachably attached to the tool body 10 in the first embodiment. Fig. 11 is a top view showing the cutting tool 100 (in a state where the cutting insert 1 is attached to the tool body 10). Fig. 12 is a right side view showing the cutting tool 100. Fig. 13 is a bottom view showing the cutting tool 100. Fig. 14 is a left side view showing the cutting tool 100. Fig. 15 is a partially enlarged view showing the cutting insert 1 shown in Fig. 11 and a portion of the surrounding structure.

[0051] The cutting insert 1 of this embodiment is made of a material harder than the main body 10A, such as cemented carbide, cermet, ceramic, diamond, or CBN.

[0052] As shown in FIG. 10, the cutting insert 1 has a tip body 1A and a cutting edge portion 1B. The tip body 1A has a generally trapezoidal shape in a plan view, and one end is tapered. A mounting hole 6 is formed in the center of the tip body 1A, penetrating it in the thickness direction. The cutting insert 1 is fixed to the tool body 10 by a mounting screw inserted into the mounting hole 6.

[0053] The tip body 1A has an upper surface 2 and a seating surface 3 (FIG. 10) that have approximately the same area in a plan view. The outer peripheral surface of the chip body 1A has long side surfaces 4a, short side surfaces 4b, a slope 4c connecting one end of the long side surfaces 4a and the short side surfaces 4b, and a first side surface 4d connecting the other end of the long side surfaces 4a and the short side surfaces 4b almost perpendicularly. The long side surfaces 4a and the short side surfaces 4b are not parallel. The short side surfaces 4b are slightly inclined toward the long side surfaces 4a as they move from the first side surface 4d toward the slope 4c. The slope 4c is inclined at a larger angle relative to the long side surfaces 4a than the short side surfaces 4b.

[0054] The cutting edge portion 1B is integral with the tip body 1A and protrudes from the other end of the tip body 1A. The cutting edge portion 1B protrudes from a first side surface 4d that constitutes the outer peripheral surface of the tip body 1A in a direction approximately perpendicular to the first side surface 4d, and has a predetermined length. When viewed from the direction of the insert center axis CO, the cutting edge portion 1B is formed closer to the short side surface 4b on one widthwise side of the tip body 1A, and its entirety is located inside an extension line Q (FIG. 15) of the short side surface 4b of the tip body 1A.

[0055] The thickness of cutting edge portion 1B is less than half the thickness of tip body 1A and is located near the center in the thickness direction of tip body 1A. The thickness of cutting edge portion 1B relative to the thickness of tip body 1A is selected depending on the strength, rigidity, and desired processing performance of cutting edge portion 1B.

[0056] The cutting edge portion 1B has a rectangular columnar shape that is long in one direction, and has a cutting edge 5 at its tip. The cutting edge 5 protrudes outward in the width direction beyond the flank 4f of the cutting edge portion 1B and extends in the thickness direction of the insert body 1A. The cutting edge 5 is located at the most distal end in both the axial and width directions. This prevents interference with the inner peripheral surface of the workpiece during machining.

[0057] The flank 4f of the cutting edge 5 is substantially perpendicular to the top surface 2. The top surface 10a of the main body portion 10A of the tool body 10 described above is a plane parallel to the top surface 2.

[0058] The cutting insert 1 is attached to the chip pocket 14 of the tool body 10 by threading a mounting screw inserted through the mounting hole 6 of the cutting insert 1 into a screw hole 15 (FIGS. 2 and 4) formed in the tool body 10 with the seating surface 3 in contact with the bottom restraint surface 14a of the chip pocket 14 in the tool body 10 (main body portion 10A). When the cutting insert 1 is attached to the tool body 10, the seating surface 3 is restrained by the bottom restraint surface 14a, the long side surface 4a of the cutting insert is restrained by the lateral restraint surface 14b of the chip pocket 14, and the inclined surface 4c is restrained by the inclined restraint surface 14c of the chip pocket 14.

[0059] 15, when viewed from the +Z direction, the cutting insert 1 of this embodiment has the short-side side surface 4b inclined relative to the long-side side surface 4a, so that a part of the bottom restraint surface 14a of the tool body 10 is exposed outside the short-side side surface 4b. In other words, the cutting insert 1 is shaped to avoid the path of the groove portion 9 on the tool body 10 side, and the entire opening on the tip side of the groove portion 9 is exposed without being obstructed by the cutting insert 1.

[0060] Fig. 16 is a view of the cutting tool 100 as seen from the front end side, and Fig. 17 is a view of the cutting tool 100 as seen from the rear end side. 16 and 17 , in the cutting tool 100 of this embodiment, the cutting edge 5 of the cutting insert 1 is located on the axis of the central axis O of the coolant channel 7. By aligning the central axis O of the coolant channel 7 with the cutting edge 5 (internal diameter machining point) of the cutting insert 1, it is possible to reliably supply the coolant discharged from the coolant channel 7 to the cutting edge 5.

[0061] The cutting tool 100 of this embodiment is composed of two structures, a main body 10A and a flow path forming member 10B, and is configured so that coolant is supplied from a coolant flow path 7 formed inside these members toward the cutting edge 5 of the cutting insert 1. The cutting edge 5 is located on the axis line of the central axis O of the coolant flow path 7, making it possible to supply coolant directly to the cutting edge 5. A groove 9 communicating with the tip of the coolant flow path 7 via a discharge opening 8 is formed in the main body 10A.

[0062] The groove 9 is provided to prevent the coolant discharged from the coolant flow path 7 (discharge port 19d of the flow path forming member 10B) from contacting the main body 10A before reaching the cutting edge 5. In this embodiment, the groove 9 reduces the pressure loss of the coolant discharged from the coolant flow path 7 (discharge port 19d) toward the cutting edge 5, and enables the coolant to be supplied directly to the cutting edge 5 (internal diameter machining point) while maintaining a high discharge pressure.

[0063] In the flow path forming member 10B of this embodiment, the discharge port 19d on the tip side and the base end opening 19e on the rear end side are arranged coaxially, so that the coolant can be discharged at high pressure without causing turbulence and is straightened at the tip side of the coolant flow path 7. Furthermore, in this embodiment, the nozzle hole 17 formed in the main body 10A is also coaxial with the flow path forming member 10B.

[0064] Therefore, pressure loss is suppressed when the coolant ejected from the flow passage forming member 10B passes through the nozzle hole 17 of the main body 10A, and the flow rate does not decrease. This makes it possible to supply a sufficient amount of coolant directly to the cutting edge 5 of the cutting insert 1 while maintaining high pressure, making it possible to efficiently remove chips from the inner diameter machining point. This prevents generated chips from becoming tangled in the cutting edge 5 and prevents damage to the cutting edge 5.

[0065] Furthermore, by supplying a sufficient amount of coolant, it is possible to suppress the heat generated when machining the workpiece, and therefore it is possible to reduce wear on the flank of the cutting insert 1.

[0066] In this embodiment, the discharge side of the coolant flow path 7, i.e., the diameter of the discharge port 19d of the flow path forming member 10B, is small, e.g., approximately 1 mm or less. If such a small hole were to be formed directly in the main body 10A using a drill, the tool material would be too hard and difficult to machine. Furthermore, if it were to be formed using electric discharge machining, the protrusion length of the electric discharge would be too long, reducing the rigidity of the main body 10A and making machining difficult. Therefore, in this embodiment, the flow path forming member 10B is provided separately from the main body 10A, and a small discharge port 19d is formed in this flow path forming member 10B. This facilitates machining, enabling accurate small-diameter machining.

[0067] Furthermore, by using a material for the flow path forming member 10B that is lower in hardness than the main body 10A, small diameter machining using a drill becomes easier. Also, even when electrical discharge machining is performed, the length of the electrode can be shortened, thereby improving machining efficiency. [Example]

[0068] The following describes the results of verification carried out to confirm the effects of the present invention. The relationship between the diameter of the discharge port 19d in the cutting tool 100 and the discharge pressure of the coolant will be described using Figure 18. Figure 18 is a graph showing the relationship between the diameter of the discharge port 19d in the cutting tool 100 and the discharge pressure of the coolant, with the horizontal axis representing the diameter of the discharge port and the vertical axis representing the coolant discharge pressure.

[0069] 18, when the diameter of the outlet is 1 mm or less, the pressure at the coolant outlet is approximately twice as high as when the diameter of the outlet is 2 mm. Therefore, in this embodiment, the diameter of the outlet 19d is set to 1 mm or less to achieve high discharge pressure.

[0070] Fig. 19A is a diagram showing the discharge pressure when the discharge port is coaxial with the central axis of the flow path forming through hole, and Fig. 19B is an enlarged view showing the flow state of the coolant near the discharge port shown in Fig. 19A. As shown in Figure 19A, in a configuration in which the discharge port is coaxial with the central axis of the flow path-forming through hole, as in an embodiment of the present invention, the discharged coolant can maintain a high pressure. The discharged coolant advances without spreading around, allowing a sufficient amount of coolant to be supplied to a specific location (local area). As shown in Figure 19B, the coolant near the discharge port in the flow path-forming through hole is rectified and no turbulence occurs. Therefore, the reduction in pressure loss is small.

[0071] Fig. 20A is a diagram showing the discharge pressure when the discharge port is radially offset from the central axis of the flow path forming through hole, and Fig. 20B is an enlarged view showing the coolant flow state near the discharge port shown in Fig. 20A. As shown in FIG. 20A, when the central axis of the flow path-forming through hole and the discharge port are not coaxial, as in the comparative example, the pressure of the discharged coolant quickly drops. The discharged coolant quickly spreads around, making it more difficult to supply a sufficient amount of coolant to a specific location than with the coaxial configuration described above. As shown in FIG. 20B, the coolant near the discharge port of the flow path-forming through hole becomes turbulent. As a result, pressure loss occurs compared to the coaxial configuration described above, making it more difficult to supply coolant at sufficient pressure.

[0072] Second Embodiment Next, a cutting tool 200 according to a second embodiment of the present invention will be described. The basic configuration of this embodiment is similar to that of the first embodiment, but the position at which the groove portion 29 is formed is different. In the above embodiment, the groove portion was formed on a surface facing the same direction as the flank surface of the cutting insert (-Y direction), but this embodiment is different in that the groove portion 29 is formed on a surface facing the same direction as the top surface 2 of the cutting insert 1 (+Z direction). Therefore, in the following explanation, the configuration that differs from the above embodiment will be explained in detail, and the explanation of the common configuration will be omitted.

[0073] Fig. 21 is a perspective view showing the overall configuration of a cutting tool 200 according to the second embodiment. Fig. 22 is a cross-sectional view taken along line XXII-XXII in Fig. 21. 21 and 22, the cutting tool 200 of this embodiment has an upwardly opening groove 29. The groove 29 is formed in the cutout portion 12 of the main body 10A, and its tip side communicates with the chip pocket 14.

[0074] The cutting tool 200 of this embodiment can obtain the same effects as those of the configuration of the first embodiment. Furthermore, according to the configuration of this embodiment, the groove portion 29 can be formed simultaneously with machining of the chip pocket 14, resulting in good work efficiency.

[0075] <Third embodiment> Next, a cutting tool 300 according to a third embodiment of the present invention will be described. The basic configuration of this embodiment is the same as that of the first embodiment, except that the central axis of the coolant flow path is partially offset. Therefore, in the following explanation, only the configuration that differs from the first embodiment will be explained in detail, and the explanation of the common configuration will be omitted. Fig. 23 is a perspective view showing the overall configuration of a cutting tool 300 according to the third embodiment, and Fig. 24 is a cross-sectional view taken along line XXIV-XXIV in Fig. 23 .

[0076] In the first embodiment described above, the three through holes 16A, 16B, and 16C that make up the flow path-forming through hole 16 formed in the main body 10A are all formed coaxially. However, in the flow path-forming through hole 36 of this embodiment, the center axis O1 of the first through hole 16A is radially offset from the center axes O2 of the other two through holes, the second through hole 16B and the third through hole 16C. Specifically, the through holes 16B and 16C are formed offset toward the tool center axis P with respect to the through hole 16A. The center axis O1 of the through hole 16A coincides with the inner diameter machining point of the cutting blade 5.

[0077] According to the configuration of this embodiment, among the flow path forming through holes 16, through holes 16B and 16C having a larger diameter than the first through hole 16A are formed at positions away from the outer peripheral surface, thereby ensuring a sufficient thickness between the outer peripheral surface. As a result, for example, even if the central axis O1 of the first through hole 16A is inclined at a predetermined angle with respect to the tool central axis P, it is possible to ensure the strength of the main body portion 10A. Furthermore, as with the above embodiment, improved discharge of cutting material and suppression of tool friction are achieved.

[0078] <Fourth embodiment> Next, a cutting tool 400 according to a fourth embodiment of the present invention will be described. The basic configuration of this embodiment is the same as that of the first embodiment, but differs in that the grooves are tapered. Therefore, in the following description, the configuration that differs from the first embodiment will be described in detail, and a description of the common configuration will be omitted.

[0079] Fig. 25 is a perspective view showing the overall configuration of a cutting tool 400 according to the fourth embodiment. Fig. 26 is a cross-sectional view taken along line XXVI-XXVI in Fig. 25. 25 and 26, a cutting tool 400 of this embodiment includes a main body 10A having a tapered groove 49. As shown in Fig. 26, when viewed from the right side (-Y direction), the width (diameter) of groove 49 increases from the base end (the discharge opening 8 side that opens into the inclined surface 13b of main body 10A) toward the tip end, and reaches its maximum width at the tip end that communicates with chip pocket 14. The width of groove 49 on the base end side is smaller than the diameter of discharge opening 8 and slightly larger than the diameter of discharge port 19d of flow path forming member 10B.

[0080] Furthermore, the base end side of groove 49 communicates with the radially inner side of discharge opening 8 that is closer to the tool center axis P. Therefore, the shape of groove 49 is closer to a circle than the discharge openings 8 of the other embodiments. Furthermore, the depth of groove 49 is not constant in the longitudinal direction but becomes shallower toward the base end side, but because the inner wall surface of groove 49 is spaced apart in the radial direction from the center axis O of the coolant flow path 7, pressure loss caused by the coolant discharged through discharge opening 8 coming into contact with the inner wall surface is suppressed.

[0081] As in the configuration of this embodiment, the side surface of the groove 49 may be tapered. Since the width of the groove 49 increases toward the tip side, even if the coolant discharged through the discharge opening 8 slightly expands before reaching the cutting edge 5 of the cutting insert 1, the groove 49 can prevent the coolant from contacting the main body 10A (groove 49). This makes it possible to obtain the same effects as those of the above embodiment.

[0082] In addition, within the scope of the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

[0083] For example, in each of the above embodiments, an indexable cutting tool in which the cutting insert is detachably attached to the tool body has been described, but the present invention is not limited to this configuration. For example, the cutting tool may be one in which the tool body and the cutting blade are integrated. [Explanation of symbols]

[0084] 4f...flank 5...Cutting edge 7...Coolant passage 8…Discharge opening (discharge port) 9, 29, 49...Groove 10...Tool body 10B...flow path forming member 14...Chip pocket (mounting part) 16c,16A,16B,16C,19A...Through hole 16A...First through-hole (first flow path) 16B…Second through hole 16C...Third through-hole (second flow path) 19d...Discharge port 100,200,300,400…Cutting tools D1, D3...Diameter O: Central axis of coolant passage O1: Central axis of the through hole 16A O2: Central axis of the through holes 16B and 16C P…Tool center axis (center axis) Q…Extension line

Claims

1. A cutting tool capable of supplying coolant toward a cutting edge of a cutting blade, The tool body has a length in one direction. a coolant flow passage extending in a longitudinal direction; a discharge port communicating with a tip of the coolant flow path; a groove portion communicating with the tip end of the coolant flow path via the discharge port; a notch portion having a notch surface located radially inward at a tip end side of the tool body; and The tool body is located at a tip end of the tool body relative to the groove portion and has the cutting blade. It has a mounting portion that can be attached, the groove portion is recessed from the notched surface with a width greater than the diameter of the discharge port, and a tip side of the groove portion reaches the attachment portion; cutting tools.

2. a central axis of the coolant flow passage is radially offset from a central axis of the tool body, and the cutting edge is located on an extension line of the central axis of the coolant flow passage; The cutting tool of claim 1 .

3. The coolant flow path has at least a first flow path and a second flow path arranged in this order from the tip side, The central axes of the first flow path, the discharge port, and the groove portion are coaxial with each other. The cutting tool according to claim 1 or 2.

4. a flow path forming member inserted into the tool body; The flow path forming member is a second through-hole at a tip thereof communicating with the discharge port and forming at least a part of the coolant flow path; A cutting tool according to any one of claims 1 to 3.

5. The groove portion is formed on a surface of the outer peripheral surface of the tool body that faces the same direction as the flank of the cutting edge. A cutting tool according to any one of claims 1 to 4.

6. The groove portion is formed on a surface of the outer peripheral surface of the tool body that faces the same direction as the rake face of the cutting edge. A cutting tool according to any one of claims 1 to 4.

7. A base end side of the coolant flow path is located more inward than a tip end side of the coolant flow path in the tool body. A cutting tool according to any one of claims 1 to 6.

8. The groove has a tapered shape that widens from the base end on the discharge port side to the tip end. eggplant, A cutting tool according to any one of claims 1 to 7.

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