Cutting tool

Abstract

To provide a cutting tool having a structure that can sufficiently supply a fluid such as coolant to the vicinity of a machining point of a work-piece even if the cutting tool itself is particularly small.SOLUTION: A cutting tool 10 comprises: a substantially columnar shank part that is provided at a base end part of the cutting tool 10 and becomes a portion to be fitted to a sleeve 210 which can be mounted on a machine tool; a cutting blade 18 located at a tip 10t; a chip discharge groove 30 which is formed toward the base end part of the cutting tool 10 from the cutting blade 18, and guides and discharges chips generated by cutting; and a groove-shaped coolant channel 40 which is provided in an outer periphery of the cutting tool 10, and supplies a coolant C toward the tip 10t. The coolant channel 40 is provided at a position being not overlapped with either the cutting blade 18 or the chip discharge groove 30.SELECTED DRAWING: Figure 8

Description

Technical Field

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

Background Art

[0002] In a so-called externally lubricated cutting tool that supplies lubricant from the outside of the tool, there is a problem that coolant hardly reaches the machining point. As a conventional technique for solving such a problem, internally lubricated cutting tools such as Patent Documents 3, 4, and 5 have been proposed. However, these internally lubricated cutting tools are not suitable for miniaturization due to their structure of supplying lubricant through a flow path provided inside. As a solution, conventional techniques such as tools with grooves provided in the shank as in Patent Documents 1 and 2 have been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of a so-called external supply type cutting tool that supplies a fluid such as a coolant from the outer peripheral side of the tool, in internal diameter machining or drilling, the fluid may not reach sufficiently close to the machining point within the workpiece (work material). In such a case, it is conceivable to use instead a so-called internal supply type cutting tool 10' that supplies the fluid through a hole 40' inside the tool (see Fig. 10). However, when performing machining with a relatively small diameter, if the tool is downsized to fit into a small hole, there may no longer be space to provide an oil supply hole within the tool.

[0005] Therefore, an object of the present invention is to provide a cutting tool having a structure capable of sufficiently supplying a fluid such as a coolant to the vicinity of the machining point of the workpiece even when the tool itself is particularly small.

Means for Solving the Problems

[0006] To solve such problems, the present inventor conducted various studies. Among conventional cutting tools, there are those that supply oil to the vicinity of the machining point by having a cooling groove in the shank portion. In such cutting tools, the direction of oil supply is exactly opposite to the direction in which chips are discharged from the vicinity of the machining point during machining. Although this may seem natural, with such a structure, the fluid discharged from the oil supply groove may push the chips back, which may interfere with chip discharge. Focusing on this point and conducting further studies, the present inventor obtained findings leading to the solution of the problems.

[0007] The present invention was conceived based on such findings, and one aspect thereof is a cutting tool, a shank portion having a substantially cylindrical shape that is provided at the base end portion of the cutting tool and serves as a portion to be attached to a sleeve that can be mounted on a machine tool, a cutting edge disposed at the tip end portion, a chip discharge groove formed from the cutting edge toward the base end portion of the cutting tool for guiding and discharging chips generated by cutting, a groove-shaped coolant flow path provided on the outer periphery of the cutting tool for supplying a coolant toward the tip end portion comprising The coolant passage is provided at a position that does not overlap with either the cutting edge or the chip discharge groove, and is a cutting tool.

[0008] In this cutting tool, the coolant passage provided on the outer periphery is in a state where it does not overlap with either the cutting edge or the chip discharge groove. In other words, since the coolant passage is not involved in the cutting edge or the chip discharge groove, the flow of the coolant supply does not interfere with the chip discharge, and the flow of the chip discharge does not interfere with the coolant supply either. Therefore, in a small cutting tool where it is difficult to provide a coolant passage inside, it is possible to adopt a structure that can sufficiently supply the coolant to the vicinity of the machining point.

[0009] In the tip view of the cutting tool as described above, the coolant passage may be provided at a position different from the chip discharge groove in the circumferential direction.

[0010] In the cutting tool as described above, the outer diameter of the shank portion may be larger than the outer diameter of the tip portion.

[0011] In the cutting tool as described above, a stepped portion may be formed between the shank portion and the portion closer to the tip than the shank portion.

[0012] In the cutting tool as described above, the coolant passage may be provided only on the outer periphery of the shank portion.

[0013] In the cutting tool as described above, a notch portion that functions as a rotation stopper for the sleeve of the machine tool is formed by a flat surface on the shank portion, and the coolant passage may be formed at a position that does not overlap with the notch portion.

[0014] In the cutting tool as described above, the coolant passage may be formed by an arc-shaped groove.

[0015] In the cutting tool as described above, the coolant flow path may be formed straight and parallel to the central axis of the cutting tool.

[0016] In the cutting tool as described above, a plurality of coolant flow paths may be provided.

[0017] In the cutting tool as described above, the cutting edge may be composed of a blade integral with the cutting tool.

[0018] In the cutting tool as described above, an insert mounting seat for mounting a cutting insert may be provided at the tip.

[0019] The cutting tool as described above may be a turning tool.

[0020] The cutting tool as described above may be a brazing tool in which a cutting insert is brazed to the tip.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying out the Invention

[0022] Hereinafter, a preferred embodiment of the cutting tool according to the present invention will be described in detail with reference to the drawings (see FIGS. 1 to 9).

[0023] The cutting tool according to the present invention is configured as a tool particularly suitable as an inner diameter processing tool such as a small turning tool or a drilling tool. The cutting tool 10 of the present embodiment includes a shank portion 14, a cutting edge 18, a chip discharge groove 30, a coolant flow path 40, etc., and is formed in a substantially cylindrical shape extending from the base end portion 10b to the tip end portion 10t along the central axis 10A (see FIGS. 1, 2, etc.). A shank portion 14 is provided on the base end portion 10b side of the cutting tool 10, and a cutting edge 18 is disposed at the tip end portion 10t.

[0024] The shank portion 14 is a portion of the cutting tool 10 that is attached to a sleeve 210 that can be mounted on a machine tool, and is provided on the base end portion 10b side of the cutting tool 10 (see FIGS. 1, 5, 6, etc.). This shank portion 14 has a substantially cylindrical shape, and a notch portion 14f that functions as a rotation stopper with respect to the sleeve 210 is formed in a part of the shank portion 14. The notch portion 14f may be a flat surface parallel to the central axis 10A (see FIG. 1, etc.). The outer diameter of the shank portion 14 in the cutting tool 10 of the present embodiment is larger than the outer diameter of other portions of the cutting tool 10 (for example, the tip end portion 10t), and is the largest portion in the cutting tool 10. A step portion 15 with a sudden change in outer diameter is formed between this shank portion 14 and the portion of the cutting tool 10 closer to the tip end portion 10t than the shank portion 14 (see FIGS. 1, 2, etc.).

[0025] 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 the present embodiment, the cutting edge 18 is composed of a blade integral with the cutting tool 10. However, this is merely a preferred example. Although not particularly shown, as the cutting tool 10, one provided with an insert mounting seat to which a cutting insert is attached at its tip portion 10t may be adopted, or a brazed tool with a brazed cutting insert may be adopted.

[0026] The chip discharge groove 30 is a groove for guiding and discharging chips (indicated by reference numeral 120 in FIG. 9) generated by cutting. The chip discharge groove 30 in the cutting tool 10 of the present embodiment is formed by a spiral pocket extending from the cutting edge 18 toward the base end portion 10b side of the cutting tool 10 (see FIGS. 1, 3, etc.).

[0027] The coolant passage 40 is formed in the cutting tool 10 so as to supply the coolant C toward the tip portion 10t. The coolant passage 40 in the cutting tool 10 of the present embodiment is composed of, for example, two oil supply grooves provided only in the outer peripheral portion of the shank portion 14 among the outer periphery (indicated by reference numeral 10p) of the cutting tool 10 (see FIGS. 2 to 6). The discharge port 40d of the coolant passage 40 is located at a portion having the step portion 15 (see FIG. 2 etc.). The coolant passage 40 may be composed of a groove having an arc-shaped cross section as in the present embodiment (see FIGS. 3 and 4), or may be composed of grooves having other shapes. These coolant passages 40 are formed straight along the direction of the central axis 10A parallel to the central axis 10A of the cutting tool 10 (see FIGS. 2, 3, etc.).

[0028] In the cutting tool 10 of the present embodiment, the coolant passage 40 is provided at a position that does not overlap with either the cutting edge 18 or the chip discharge groove 30 (see FIG. 2 etc.). For example, when this cutting tool 10 is viewed from the tip portion 10t (referred to as a tip view in this specification), the coolant passage 40 is provided at a position different from the chip discharge groove 30 in the circumferential direction (a position that does not overlap with the chip discharge groove 30 in the circumferential direction) (see FIG. 3). In such a cutting tool 10, the coolant passage 40 is in a state where it does not overlap with either the cutting edge 18 or the chip discharge groove 30, in other words, a state where it is not involved with the cutting edge 18 or the chip discharge groove 30 (see FIG. 7 etc.). Therefore, the flow of the coolant C supplied to the tip portion 10b side through the coolant passage 40 does not hinder the discharge of the chips 120, and the chip discharge flow does not hinder the oil supply either (see FIG. 8 etc.). For this reason, in a particularly small cutting tool 10 etc. where it is difficult to provide the coolant passage 40 inside, it becomes possible to sufficiently supply the coolant C to the vicinity of the machining point of the workpiece 100 (see FIG. 9). Therefore, according to the cutting tool 10 as in the present embodiment, when applied to an inner diameter machining tool such as a particularly small turning tool or a drilling tool, it is possible to effectively perform oil supply from the shank portion 14 toward the inside of the workpiece 100, discharge of the chips 120, cooling of the cutting edge, and lubrication.

[0029] The coolant flow path 40 as described above is also formed at a position that does not overlap with the notch 14 (see FIGS. 2, 4, etc.). In this embodiment, when viewing the two coolant flow paths 40 from the base end portion 10b (base end view), examples are shown where they are respectively arranged at positions of 105° or more and 135° or less in the clockwise and counterclockwise directions with reference to the center position of the notch 14f (for example, at a position of approximately 120°) (in other words, when viewing from the tip end portion 10t (tip end view) (see FIG. 3), examples are shown where they are arranged at positions of 65° or more and 95° or less in the clockwise direction and 155° or more and 185° or less in the counterclockwise direction with reference to the straight line connecting the central axis 10A and the outermost part of the cutting edge 18) (see FIG. 4). However, this is merely an example of a suitable arrangement, and as long as it does not overlap with the cutting edge 18, the chip discharge groove 30, and further the notch 14, the specific position is not limited. Also, the number of the coolant flow paths 40 is not limited, and furthermore, the shape and form of the coolant flow path 40 are not limited either. Also, when providing a plurality of coolant flow paths 40, their sizes and shapes may be different from each other.

[0030] Note that the above-described embodiment is merely a preferred example of the present invention and is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

Industrial Applicability

[0031] The present invention is suitable for application to a cutting tool.

Explanation of Reference Numerals

[0032] 10... Cutting tool 10A... Central axis 10b... Base end portion 10p... Outer periphery 10t... Tip end portion 14... Shank portion 14f... Notch 15... Step portion 18... Cutting edge 30... Chip discharge groove 40... Coolant flow path 40d... discharge port 100... workpiece (material to be machined) 120... chips 210... sleeve C... coolant

Claims

1. A cutting tool comprising: a shank portion having a substantially cylindrical shape, which is a portion to be attached to a sleeve provided at a base end portion of the cutting tool and mountable on a machine tool; a cutting edge disposed at the tip end portion; a chip discharge groove formed from the cutting edge toward the base end portion of the cutting tool for guiding and discharging chips generated by cutting; a groove-shaped coolant passage provided on an outer periphery of the cutting tool for supplying coolant toward the tip end portion; and the coolant passage is provided at a position that does not overlap with either the cutting edge or the chip discharge groove.

2. The cutting tool according to claim 1, wherein in a tip view seen from the tip end portion, the coolant passage is provided at a position different from the chip discharge groove in the circumferential direction.

3. The cutting tool according to claim 2, wherein an outer diameter of the shank portion is larger than an outer diameter of the tip end portion.

4. The cutting tool according to claim 3, wherein a stepped portion is formed between the shank portion and a portion closer to the tip end portion than the shank portion.

5. The cutting tool according to claim 4, wherein the coolant passage is provided only on an outer periphery of the shank portion.

6. The cutting tool according to claim 5, wherein a notch portion that functions as a rotation stopper for the sleeve of the machine tool on the shank portion is constituted by a flat surface, and the coolant passage is formed at a position that does not overlap with the notch portion.

7. The cutting tool according to claim 1, wherein the coolant passage is constituted by an arcuate groove.

8. The cutting tool according to any one of claims 1 to 7, wherein the coolant passage is formed straight parallel to a central axis of the cutting tool.

9. The cutting tool according to claim 8, wherein a plurality of the coolant passages are provided.

10. The cutting tool according to any one of claims 1 to 7, wherein the cutting edge is constituted by a blade integral with the cutting tool.

11. The cutting tool according to any one of claims 1 to 7, wherein an insert mounting seat for mounting a cutting insert is provided at the tip end portion.

12. The cutting tool according to any one of claims 1 to 7, which is a turning tool.

13. The cutting tool according to any one of claims 1 to 7, which is a brazing tool for brazing a cutting insert at the tip end portion.

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