Cutting tool

Abstract

To provide a cutting tool in which a holding assembly can be replaced more easily.SOLUTION: A cutting tool 1 according to one aspect of the present invention includes: a polygonal portion 2 having a substantially square shape surrounded by a first flat surface 21 on one tip side of a shaft; a chamfered portion 3 in which at least three second flat surfaces 31 are distributedly arranged via arcs along a circumferential direction of the shaft on a deeper side than the polygonal portion; and a cutting portion 4 having a spiral convex portion 41 formed on the other end side.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A screw is a component having a helical protrusion formed around a cylindrical or conical shaft member, and is an indispensable component when assembling and fixing multiple components together.

[0003] On the other hand, it is important that the screw has a hole with a thread groove formed in the member to be fixed so that the screw can fit into a protrusion formed around the screw. In order to form this hole with a thread groove, for example, a tool called a "tap" is useful.

[0004] Like the screw described above, a tap has a helical protrusion formed at its tip, and by inserting this tap into a pre-formed hole (a hole without threads) while turning it, a thread groove corresponding to the protrusion can be formed on the inner circumference of the hole.

[0005] A technique relating to tapping is described in, for example, Non-Patent Document 1 below. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] https: / / sakusakuec.com / shop / pg / 1tap02 / Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, a typical tap as exemplified in the above-mentioned Non-Patent Document 1 is configured to have a cutting portion on one side of a shaft where a helical convex portion is formed, and a shank portion on the other side. By fixing and connecting this shank portion to a holder such as a tap handle for rotating the tap by hand or a tap holder for rotating the tap by a machine tool, a user can efficiently rotate the tap and form a thread groove.

[0008] However, taps require the replacement of the tap handle, tap holder, and other holders each time they are used, and this replacement work is very time-consuming. In particular, although there are many different types of taps, a suitable holder must be selected to hold the tap. Conversely, if there is no suitable holder, the tap cannot be used. This problem is not limited to taps, but applies to cutting tools in general.

[0009] In view of the above, an object of the present invention is to provide a cutting tool that allows the holder to be more easily replaced. [Means for solving the problem]

[0010] A cutting tool according to one aspect of the present invention which solves the above-mentioned problems has a polygonal portion surrounded by a first flat surface at one tip side of a shaft, and a chamfered portion, further back than the polygonal portion, in which at least three second flat surfaces are distributed via circular arcs along the circumferential direction of the shaft.

[0011] In this respect, although not limited thereto, it is preferable that the width of the second flat surface of the chamfered portion is equal to or less than half the diameter of the shaft.

[0012] In this respect, although not limited thereto, it is preferable that the three second flat surfaces of the chamfered portion are arranged at approximately equal intervals along the circumferential direction of the shaft.

[0013] In this respect, although not limited thereto, it is preferable that the cross section of the polygonal portion is substantially square.

[0014] In this respect, although not limited thereto, it is preferable that the other end side of the shaft has a cutting portion on which a helical protrusion is formed. Effect of the Invention

[0015] As described above, the present invention can provide a cutting tool that allows the holder to be replaced more easily. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram showing an outline of a cutting tool according to an embodiment; [Diagram 2] 1 is a diagram showing an outline of a cutting tool according to an embodiment; [Diagram 3] FIG. 2 is a partial cross-sectional view of a cutting tool according to an embodiment. [Figure 4] FIG. 2 is a diagram showing an image of a cutting tool according to an embodiment when held by a tap handle. [Diagram 5] FIG. 4 is a diagram showing an image of a cutting tool according to an embodiment when held by a chuck. BEST MODE FOR CARRYING OUT THEINVENTION

[0017] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention can be embodied in many different forms, and is not limited to the specific examples described in the following embodiments and examples.

[0018] Fig. 1 is a schematic diagram of a cutting tool (hereinafter referred to as "the tool") 1 according to this embodiment. Fig. 2 is a schematic diagram of the tool when viewed along the extension direction of the shaft. Fig. 3 is a cross section of a part of the tool (chamfered portion) taken along a plane perpendicular to the extension direction of the shaft.

[0019] As shown in these figures, the tool 1 has a polygonal portion 2 surrounded by a first flat surface 21 at one tip side of the shaft, and a chamfered portion 3 behind the polygonal portion 2, in which at least three second flat surfaces 31 are distributed via circular arcs along the circumferential direction of the shaft.

[0020] As will become clear from the description below, by providing not only the polygonal portion 2 but also the chamfered portion 3 at one end (tip side) of the shaft, this tool 1 can be fixed to various holders. Specifically, the polygonal portion 2 can be attached to, for example, a tap handle, and the chamfered portion 3 can be attached to a chuck. In other words, it becomes possible to more easily change the holder.

[0021] As described above, the tool 1 has a polygonal portion 2 surrounded by a first flat surface 21 at one end of the shaft. Providing the polygonal portion 2 makes it possible to fix the tool to a tap handle H or the like, as described above. An image of the tool 1 held by a tap handle is shown in Figure 4.

[0022] The polygonal portion 2 of the present tool 1 is a portion whose surface is cut by a plurality of first flat surfaces 21, and whose cross section is polygonal. This polygonal portion can be stably held by inserting it into a holder having a hole of the same shape as this polygon. Here, "first" is an ordinal number used to distinguish it from the flat surface (second flat surface) in the chamfered portion 3, and the ordinal number itself does not have any technical meaning.

[0023] From this viewpoint, although not limited thereto, it is preferable that the cross section of the polygonal portion 2 is substantially square. Here, "substantially" square means not only a perfect square, but also manufacturing errors and even a case where the corners of the square are chamfered. Since many holders have square holes, making the cross section square makes it possible to install the holder on these holders.

[0024] Furthermore, the present tool 1 has a chamfered portion 3 on the rear side of the polygonal portion 2, in which at least three second flat surfaces 31 are distributed along the circumferential direction of the shaft via circular arcs. The cross-sectional view is as shown in Fig. 2 above. Since the present tool 1 has at least three second flat surfaces 31, it can be fixed to a holder such as a chuck. An image of this case is shown in Fig. 5.

[0025] Moreover, the tool 1 has a cutting part 4 with a spiral protrusion 41 formed on the other end of the shaft. The cutting part 4 is an essential part that exerts the function of the tool 1. However, the tool 1 is an essential part as long as it can be held by various holders, but the type of the holder is not important, and it may have another shape without being limited to a spiral protrusion.

[0026] In addition, in the present tool 1, the three second flat surfaces 31 of the chamfered portion 3 are preferably arranged at approximately equal intervals along the circumferential direction of the shaft. Generally, a tool such as a chuck has three holding jaws arranged evenly in the circumferential direction, so arranging them in this manner makes it possible to reliably fix the tool such as a chuck.

[0027] Furthermore, in the present tool 1, although not limited thereto, the width of the second flat surface 31 of the chamfered portion 3 is preferably equal to or less than half the diameter of the shaft. In the present tool 1, at least three second flat surfaces 31 are distributed along the circumferential direction of the shaft via arcs, and for this purpose, by making the width equal to or less than half the diameter of the shaft (equal to or less than the radius), as described above, it becomes possible to make the interior angles of the flat surface portion and the arc portion equal. On the other hand, if the width of the second flat surface 31 is too thin, the contact area with a tool such as a chuck is reduced, thereby reducing the fixing ability, so the width is preferably equal to or more than one-fourth the diameter of the shaft. [Industrial Applicability]

[0028] The present invention has industrial applicability as a cutting tool. [Explanation of symbols]

[0029] 1...Cutting tools 2...Polygonal section 21...First flat surface 3… Chamfered part 31...Second flat surface 4…Cutting part 41…Convex part

Claims

1. One end of the shaft has a polygonal portion surrounded by a first flat surface, A cutting tool having a chamfered portion located behind the polygonal portion, in which at least three second flat surfaces are dispersed along the circumferential direction of the axis via circular arcs.

2. The cutting tool according to claim 1, wherein the width of the second flat surface of the chamfered portion is less than or equal to half the diameter of the shaft.

3. The cutting tool according to claim 1, wherein the three second flat surfaces of the chamfered portion are arranged at substantially equal intervals along the circumferential direction of the axis.

4. The cutting tool according to claim 1, wherein the cross-section of the polygonal portion is substantially square.

5. The cutting tool according to claim 1, having a cutting portion on the other end of the shaft having a spiral projection.

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