Cutting tool

Abstract

To provide a cutting tool that can sufficiently supply fluid such as coolant to the vicinity of a processing point of a work-piece also when the tool itself is particularly small-sized, and has a structure with improved blade tip cooling performance and chip discharge performance.SOLUTION: A cutting tool 10 comprises: a shank part 14 which is provided at a base end part 10b, and has a substantially cylindrical shape; a cutting edge 18 located at a tip 10t; a chip discharge groove 30 which is formed toward the base end part 10b from the cutting edge 18, and guides and discharges chips generated by cutting; and a plurality of groove-like coolant channels 40 which are provided on an outer periphery 10p of the cutting tool 10, and supply a coolant toward the tip 10t. A first coolant channel 41, which is one of the plurality of coolant channels 40, is located on an upper side of the cutting edge 18 in a tip view viewing from the tip 10t along a central axis 10A extending in a longer direction of the cutting tool 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] External coolant supply type cutting tools, which are supplied with coolant from outside the tool, have the problem of making it difficult for coolant to reach the machining point. Internal coolant supply type cutting tools, such as those disclosed in Patent Documents 3, 4, and 5, have been proposed as prior art to solve this problem. However, these internal coolant supply type cutting tools are not suitable for miniaturization due to their structure, in which coolant is supplied through internally provided flow channels. As a solution to this problem, prior art tools with grooves in the shank, such as those disclosed in Patent Documents 1 and 2, have been proposed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2013-501638 [Patent Document 2] Special Publication No. 2013-519537 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-71608 [Patent Document 4] Japanese Patent Application Laid-Open No. 2007-185765 [Patent Document 5] Japanese Patent Application Laid-Open No. 2010-105084 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with external supply-type cutting tools, in which coolant or other fluids are supplied from the outer periphery of the tool, the fluid may not reach the workpiece (workpiece) near the machining point during internal machining or drilling. In such cases, an internal supply-type cutting tool 10', in which the fluid is supplied through a hole 40' inside the tool (see Figure 7), may be used instead. However, when machining relatively small diameters, if the tool is made small enough to fit into the small hole, there may no longer be space for an oil supply hole inside the tool. Furthermore, there is a real demand for external supply-type cutting tools, especially small cutting tools, to be able to sufficiently cool the cutting edge, thereby extending their lifespan and further improving chip removal.

[0005] Therefore, an object of the present invention is to provide a cutting tool that is capable of sufficiently supplying a fluid such as coolant to the vicinity of the machining point of a workpiece even when the tool itself is particularly small, and that has a structure that improves the cooling performance of the cutting edge and the performance of discharging cutting chips. [Means for solving the problem]

[0006] The present inventors conducted extensive research to solve this problem. Some conventional cutting tools have cooling grooves in the shank that supply oil to the vicinity of the cutting point. However, the oil supply direction in such cutting tools is opposite to the direction in which chips are discharged from the vicinity of the cutting point during machining. While this may seem obvious, with such a structure, the fluid discharged from the oil supply grooves can push the chips back in, hindering chip discharge. Focusing on these points, the present inventors conducted further research from the perspective of improving the cooling performance of the cutting edge and the chip discharge performance, and arrived at findings that led to a solution to the problem.

[0007] The present invention has been conceived based on such findings, and one aspect thereof is a cutting tool, comprising: a shank portion having a substantially cylindrical shape, which is provided at a base end of the cutting tool and is attached to a sleeve that can be mounted on a machine tool; A cutting edge arranged at the tip, a chip discharge groove formed from the cutting edge toward the base end of the cutting tool for guiding and discharging chips generated by cutting; a plurality of groove-shaped coolant flow paths provided on the outer periphery of the cutting tool for supplying coolant toward the tip portion; Equipped with The cutting tool has a first coolant flow path, which is one of the multiple coolant flow paths, that is positioned above the cutting edge when viewed from the tip along a central axis extending in the longitudinal direction of the cutting tool.

[0008] In this cutting tool, by arranging any of the multiple coolant passages on the outer periphery in a position that does not overlap with either the cutting edge or the chip discharge groove—in other words, by ensuring that the coolant passage is not involved in the cutting edge or the chip discharge groove—it is possible to prevent the oil supply flow from interfering with chip discharge and the chip discharge flow from interfering with oil supply. Furthermore, by arranging one of the multiple coolant passages, the first coolant passage, above the cutting edge when viewed from the tip, it is possible to improve the cooling performance of the cutting edge and the discharge performance of chips.

[0009] In the cutting tool as described above, the first coolant passage may be arranged on the outer periphery of the cutting tool on the side where the rake face of the cutting edge is located.

[0010] In the cutting tool as described above, the first coolant passage may be disposed at a position where a perpendicular line perpendicular to the cutting edge passes through in a tip view seen from the tip portion.

[0011] In the cutting tool as described above, the first coolant passage may be disposed at a position that does not communicate with the chip discharge groove when viewed from the tip end portion.

[0012] In the cutting tool as described above, among the multiple coolant flow paths, those other than the first coolant flow path may be arranged in a position that does not overlap with either the cutting edge or the chip discharge groove when viewed from the tip end.

[0013] In the cutting tool as described above, among the plurality of coolant passages, a second coolant passage and a third coolant passage may be provided in addition to the first coolant passage.

[0014] In the cutting tool described above, the second coolant passage and the third coolant passage may be provided at positions different from the chip discharge grooves in the circumferential direction when viewed from the tip end portion.

[0015] In the cutting tool as described above, a notch may be provided at the tip portion to enlarge the flow path of the coolant supplied from the coolant flow path to the chip discharge groove.

[0016] In the cutting tool as described above, the notch may be formed with an inclined surface that is not perpendicular to the central axis.

[0017] In the cutting tool as described above, the notch may be provided on the side of the tip portion where the second coolant passage or the third coolant passage is located, as seen from the tip end.

[0018] In the cutting tool as described above, the shank portion may have an outer diameter larger than the outer diameter of the tip portion.

[0019] In the cutting tool as described above, a step may be formed between the shank portion and a portion closer to the tip end than the shank portion.

[0020] In the cutting tool as described above, the plurality of coolant passages may all be provided only on the outer periphery of the shank portion.

[0021] In the cutting tool as described above, the shank portion may have a notch portion formed of a flat surface that functions as a rotation stopper for the sleeve of the cutting machine, and the coolant flow path may be formed in a position that does not overlap with the notch portion.

[0022] In the cutting tool described above, the coolant passage may be formed as an arc-shaped groove.

[0023] In the cutting tool described above, the coolant flow passage may be formed straight and parallel to the central axis of the cutting tool.

[0024] In the cutting tool as described above, the chip discharge flute may be formed in a spiral shape.

[0025] In the cutting tool as described above, the cutting edge may be formed as an integral blade with the cutting tool.

[0026] In the cutting tool as described above, an insert mounting seat for mounting a cutting insert may be provided at the tip portion.

[0027] The cutting tool may be a turning tool.

[0028] The cutting tool as described above may be a brazed tool having a cutting insert brazed to the tip thereof. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view showing an example of a cutting tool according to the present invention. [Figure 2] FIG. 2 is a perspective view of the cutting tool as seen from another angle. [Figure 3] FIG. 1 is a diagram of a cutting tool as seen from the tip (tip view). [Figure 4] FIG. 2 is a view of the cutting tool as seen from the base end (base end view). [Figure 5] FIG. 2 is a perspective view showing the flow of coolant on the inclined surface (notch) at the tip of the cutting tool. [Figure 6] FIG. 2 is a diagram illustrating the internal state of a workpiece (workpiece) during drilling. [Figure 7] FIG. 1 is a perspective view showing an example of a conventional cutting tool for reference. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, preferred embodiments of the cutting tool according to the present invention will be described in detail with reference to the drawings (see FIGS. 1 to 6).

[0031] The cutting tool according to the present invention is configured as a tool suitable for internal machining, particularly for small turning tools and drilling tools. The cutting tool 10 of this embodiment includes a shank 14, cutting edges 18, chip grooves 30, coolant channels 40, and the like, and is formed in a generally cylindrical shape extending from a base end 10b to a tip end 10t along a central axis 10A (see FIGS. 1 and 2, etc.). The shank 14 is provided on the base end 10b side of the cutting tool 10, and the cutting edges 18 are disposed at the tip end 10t.

[0032] The shank portion 14 is a portion of the cutting tool 10 that is attached to a sleeve (designated by reference numeral 210 in FIG. 7) that can be mounted on a machine tool, and is provided on the base end 10b side of the cutting tool 10 (see FIGS. 1, 2, etc.). The shank portion 14 is generally cylindrical, and a cutout portion 14f that functions as a rotation stopper for the sleeve 210 is formed in a portion of the shank portion 14. The cutout portion 14f may be a flat surface parallel to the central axis 10A (see FIG. 1, etc.). The shank portion 14 of the cutting tool 10 of this embodiment has an outer diameter that is larger than the outer diameters of other portions of the cutting tool 10 (e.g., the tip portion 10t), making it the largest portion of the cutting tool 10. A step portion 15, where the outer diameter suddenly changes, is formed between the shank portion 14 and a portion of the cutting tool 10 closer to the tip portion 10t than the shank portion 14 (see FIGS. 1, 2, etc.).

[0033] The cutting edge 18 is composed of a blade disposed at the tip portion 10t (see FIG. 1, etc.). In the cutting tool 10 of this embodiment, the cutting edge 18 is composed of a blade that is integral with the cutting tool 10. However, this is merely one suitable example. Although not specifically shown, the cutting tool 10 may be one in which an insert mounting seat for mounting a cutting insert is provided at the tip portion 10t, or a brazed tool to which a cutting insert is brazed may be used.

[0034] The chip groove 30 is a groove for guiding and discharging chips (indicated by reference numeral 120 in FIG. 6) generated by cutting. The chip groove 30 in the cutting tool 10 of this embodiment is formed as a spiral pocket extending from the rake face 18s of the cutting edge 18 toward the base end 10b of the cutting tool 10 (see FIGS. 1, 3, etc.).

[0035] The coolant flow passage 40 is formed in the cutting tool 10 so as to supply coolant C toward the tip portion 10t. The coolant flow passage 40 in the cutting tool 10 of this embodiment is configured with, for example, three oil supply grooves provided only on the outer periphery of the shank portion 14 of the outer periphery (indicated by the reference symbol 10p) of the cutting tool 10 (see FIGS. 1 to 4). The discharge port 40d of the coolant flow passage 40 is located at the portion where the step portion 15 is located (see FIGS. 1 and 2). The coolant flow passage 40 may be configured with a groove having an arc-shaped cross section as in this embodiment (see FIGS. 3 and 4), or may be configured with a groove of another shape. These coolant flow passages 40 are formed straight in parallel with and along the central axis 10A of the cutting tool 10 (see FIGS. 2, 3, etc.).

[0036] 3 will be referred to as the first coolant flow path, the coolant flow path on the left side as the second coolant flow path, and the coolant flow path on the lower side as the third coolant flow path, and will be respectively denoted by the reference numerals 41, 42, and 43. Below, the second coolant flow path 42 and the third coolant flow path 43 will be described first, followed by the first coolant flow path 41, and then the cutout portion 11 at the tip end 10t will be described (see FIGS. 1 to 4).

[0037] [Second and third coolant passages] The second coolant passage 42 and the third coolant passage 43 in the cutting tool 10 of this embodiment are provided in positions that do not overlap with either the cutting edge 18 or the chip discharge groove 30 (see FIG. 3, etc.). For example, when the cutting tool 10 is viewed from the tip 10t (referred to herein as a tip view), the second coolant passage 42 and the third coolant passage 43 are provided in positions that are different from the chip discharge groove 30 in the circumferential direction (positions that do not overlap with the chip discharge groove 30 in the circumferential direction) (see FIG. 3). In this cutting tool 10, the second coolant passage 42 and the third coolant passage 43 do not overlap with either the cutting edge 18 or the chip discharge groove 30, in other words, they are not involved in the cutting edge 18 or the chip discharge groove 30. Therefore, the flow of coolant C supplied to the tip portion 10t through the coolant passages 42, 43 does not interfere with the discharge of chips 120, and the flow of chip discharge does not interfere with oil supply (see FIG. 6). Therefore, even in a particularly small cutting tool 10 in which it is difficult to provide the second coolant passage 42 and the third coolant passage 43 internally, it is possible to sufficiently supply coolant C to the vicinity of the machining point of the workpiece 100. Therefore, according to the cutting tool 10 of this embodiment, when applied to an internal machining tool such as a small turning tool or drilling tool, oil can be supplied from the shank portion 14 toward the inside of the workpiece 100, effectively discharging chips 120 and cooling and lubricating the cutting edge.

[0038] The second coolant flow passage 42 and the third coolant flow passage 43 as described above are also formed at positions that do not overlap with the cutout portion 14f (see FIG. 1, etc.). Note that in this embodiment, when viewed from the base end portion 10b (base end view), the second coolant flow passage 42 is arranged at a position of 105° to 135° (for example, at a position of approximately 120°) clockwise from (the center position of) the cutout portion 14f (in other words, when viewed from the tip portion 10t (tip view) (see FIG. 3), the second coolant flow passage 42 is arranged at a position of 155° to 185° counterclockwise from the line connecting the central axis 10A and the outermost part of the cutting edge 18). In the example shown in FIG. 4, the cutting edge 14f is disposed at an angle of 105° to 135° (for example, approximately 120°) counterclockwise from (the center position of) the notched portion 14f (in other words, when viewed from the tip 10t (tip view) (see FIG. 3), the cutting edge 14f is disposed at an angle of 65° to 95° clockwise from the line connecting the central axis 10A and the outermost part of the cutting edge 18) (see FIG. 4). However, these are merely examples of suitable arrangements, and the specific position is not limited as long as the arrangement does not overlap with the cutting edge 18, the chip discharge groove 30, or the notched portion 14f.

[0039] [First coolant passage] In the cutting tool 10 of this embodiment, the first coolant passage 41 is positioned above the cutting edge 18, more specifically, on the side of the rake face 18s of the cutting edge 18, with the cutting edge 18 facing upward when viewed from the tip end 10t along the central axis 10A (see FIG. 3). If a perpendicular line PL is assumed to intersect the cutting edge 18 perpendicularly when viewed from the tip end 10t (see FIG. 3), the first coolant passage 41 in this embodiment is positioned at a location where the perpendicular line PL passes. The first coolant passage 41 is also positioned such that the outer periphery 10p is between the first coolant passage 41 and the chip groove 30 (see FIG. 1). As a result, the first coolant passage 41 in this embodiment does not communicate with the chip groove 30 when viewed from the tip end 10t (see FIG. 3).

[0040] In this way, with the cutting tool 10 of this embodiment having a structure in which the first coolant passage 41, which is one of the multiple coolant passages, is located above the cutting edge 18 when viewed from the tip, increasing the amount of coolant C supplied from the first coolant passage 41 toward the cutting edge 18 makes it possible to improve the cooling performance of the cutting edge of the cutting edge 18 and also improve the discharge performance of chips 120. Note that the first coolant passage 41 is located in a position that overlaps with the chip discharge groove 30 when viewed from the tip end 10t (see FIG. 4), and therefore, from this drawing alone, it may appear that the coolant C supplied from the first coolant passage 41 impedes chip discharge. However, in reality, the chip groove 30 is formed as a spiral pocket extending from the rake face 18s of the cutting edge 18 toward the base end 10b, so in terms of the three-dimensional structure, the first coolant passage 41 and the chip groove 30 do not overlap for the most part (see Figure 1, etc.). Therefore, contrary to the impression one might get from Figure 4, etc., the coolant C supplied from the first coolant passage 41 does not interfere with chip discharge.

[0041] [Notch at the tip] In this embodiment, the tip end 10t of the cutting tool 10 is provided with a cutout 11 that enlarges the flow path of the coolant C supplied from the coolant flow path 40 to the chip discharge groove 30 (see FIGS. 1 to 3). A specific example of such a cutout 11 is an inclined surface that is not perpendicular to the central axis 10A and is provided on the side of the tip end 10t where the second coolant flow path 42 is located, as viewed from the tip end (see FIG. 4, etc.). This inclined surface is provided so as to be inclined toward the second coolant flow path 42 (the inclination increases from the tip end 10t to the base end 10b as it approaches the second coolant flow path 42) (see FIG. 1, etc.). The cutout portion 11 having an inclined surface connected to the chip discharge groove 30 increases the space within the workpiece 100 in which the coolant C can circulate, making it easier for the coolant C to flow through the cutting edge 18 and the chip discharge groove 30, thereby facilitating cooling of the cutting edge of the cutting edge 18 and the discharge of chips 120 (see FIGS. 5 and 6). Note that the inclined surface described here is merely one suitable example of the cutout portion 11 that can perform this function, and the specific structure and form are not limited to this inclined surface. The cutout portion 11 may be formed, for example, as a curved surface, or may be formed with grooves or irregularities. Furthermore, the location of the cutout portion 11 is not limited to a position near the second coolant flow path 42.

[0042] The above-described embodiment is a preferred example of the present invention, but is not limited thereto and various modifications are possible within the scope of the present invention. For example, in the above-described embodiment, an example is given in which there are three coolant flow paths 40 (first coolant flow path 41, second coolant flow path 42, and third coolant flow path 43), but the number of these coolant flow paths 40 is not particularly limited, and the shape and configuration of the coolant flow paths 40 are not particularly limited. Furthermore, when multiple coolant flow paths 40 are provided, the coolant flow paths 40 may have different sizes and shapes. [Industrial Applicability]

[0043] The present invention is suitable for application to cutting tools. [Explanation of symbols]

[0044] 10…Cutting tools 10A…Center axis 10b...Proximal end 10p...Outer circumference 10t...Tip 11...Inclined surface (notch) 14...Shank 14f...Notch 15...Step 18...Cutting edge 18s...Scooping surface 30...Chip discharge groove 40...Coolant passage 40d…Discharge port 41...First coolant passage (coolant passage arranged on the upper side of the cutting edge) 42...Second coolant passage 43...Third coolant passage 100...Workpiece (material to be cut) 120...Chips 210...Sleeve C...Coolant PL: A perpendicular line that intersects the cutting edge

Claims

1. A cutting tool, a shank portion having a substantially cylindrical shape, which is provided at a base end of the cutting tool and is attached to a sleeve that can be mounted on a machine tool; A cutting edge disposed at the tip portion; a chip discharge groove formed from the cutting edge toward the base end of the cutting tool for guiding and discharging chips generated by cutting; a plurality of groove-shaped coolant flow paths provided on the outer periphery of the cutting tool for supplying coolant toward the tip portion; Equipped with A cutting tool, wherein a first coolant flow path, which is one of the plurality of coolant flow paths, is arranged above the cutting edge when viewed from the tip along a central axis extending in the longitudinal direction of the cutting tool.

2. The cutting tool according to claim 1 , wherein the first coolant passage is disposed on a side of the outer periphery of the cutting tool where a rake face of the cutting edge is located.

3. The cutting tool according to claim 2 , wherein the first coolant flow passage is disposed at a position where a perpendicular line perpendicular to the cutting edge passes through in a tip view from the tip portion.

4. The cutting tool according to claim 3 , wherein the first coolant passage is disposed at a position not communicating with the chip groove when viewed from the tip end portion.

5. 5. The cutting tool according to claim 4, wherein among the plurality of coolant passages, those other than the first coolant passage are provided at positions that do not overlap with either the cutting edge or the chip discharge groove in a tip view from the tip portion.

6. The cutting tool according to claim 5 , wherein a second coolant passage and a third coolant passage are provided among the plurality of coolant passages other than the first coolant passage.

7. 7. The cutting tool according to claim 6, wherein, in a tip view from the tip portion, the second coolant passage and the third coolant passage are provided at positions different from the chip discharge grooves in the circumferential direction.

8. The cutting tool according to claim 7 , wherein the tip portion is provided with a notch portion that enlarges a flow path for the coolant supplied from the coolant flow path to the chip discharge groove.

9. The cutting tool according to claim 8 , wherein the cutout portion is configured with an inclined surface that is not perpendicular to the central axis.

10. The cutting tool according to claim 8 , wherein the notch is provided on a side of the tip end portion on which the second coolant flow path or the third coolant flow path is located, in a tip end view.

11. The cutting tool according to claim 7 , wherein the shank portion has an outer diameter larger than an outer diameter of the tip portion.

12. The cutting tool according to claim 11 , wherein a step is formed between the shank portion and a portion closer to the tip portion than the shank portion.

13. The cutting tool according to claim 12 , wherein all of the plurality of coolant passages are provided only on the outer periphery of the shank portion.

14. 14. The cutting tool according to claim 13, wherein the shank portion has a notch portion formed of a flat surface that functions as a rotation stopper for the sleeve of the cutting machine, and the coolant flow path is formed in a position that does not overlap with the notch portion.

15. The cutting tool according to claim 1 , wherein the coolant flow passage is formed by an arc-shaped groove.

16. The cutting tool according to claim 1 , wherein the coolant flow passage is formed straight and parallel to a central axis of the cutting tool.

17. The cutting tool according to claim 16, wherein the chip flute is formed in a spiral shape.

18. 16. The cutting tool according to claim 1, wherein the cutting edge is formed as an integral blade with the cutting tool.

19. The cutting tool according to claim 1 , wherein the tip portion is provided with an insert mounting seat for mounting a cutting insert thereon.

20. 16. The cutting tool according to any one of claims 1 to 15, which is a turning tool.

21. The cutting tool according to claim 1 , wherein the cutting tool is a brazed tool having a cutting insert brazed to the tip portion.

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