Cutting Tools

Abstract

An object of the present invention is to provide a cutting tool that is capable of performing hole drilling like a drill and also capable of performing side machining and the like like an end mill. [Solution] The cutting tool of the present invention is a cutting tool 1 that rotates around an axis TT, and comprises a tip portion 10 having a tip cutting edge 11 formed thereon, and a main body portion 20 connected to the rear end side of the tip portion 10 and having a spiral chip discharge groove 21 formed around the axis, and an outer peripheral cutting edge 23 is formed along a leading edge 22 on the main body portion 20, and a plurality of inner grooves 25 are formed on the inner surface of the chip discharge groove 21 on the cutting surface of the outer peripheral cutting edge 23, inclining towards the rear end and intersecting with the outer peripheral cutting edge 23.

Description

[Technical field]

[0001] The present invention relates to a cutting tool that has a hole-making function like a drill and also has a side surface machining function like an end mill. [Background technology]

[0002] Conventionally, drills have been used to make holes in workpieces, and end mills have been used to machine grooves, side surfaces, and other shapes on workpieces. In drills, cutting is performed by the tip cutting edge, and the cutting chips are guided into a spiral groove and discharged from the hole to the outside. In end mills, cutting is performed by the tip cutting edge and a cutting edge formed in a spiral shape on the outer periphery, and the cutting chips are discharged to the outside.

[0003] Various types of drills and end mills have been proposed depending on the material of the workpiece and the processing conditions. For example, Patent Document 1 describes a composite material drill having a tip portion with a tip cutting edge formed thereon, a tapered portion connected to the rear end side of the tip portion and formed in a tapered shape, and a straight portion connected to the rear end side of the tapered portion and having a finish processing diameter equal to or greater than the outer diameter of the rear end side of the tapered portion, with a spirally twisted chip discharge groove formed on the outer periphery of the tapered portion and an outer peripheral cutting edge formed along the edge of the chip discharge groove on the straight portion side.

[0004] Moreover, Patent Document 2 describes a rotary tool in which discharge grooves and ridges are formed on the outer peripheral surface of a cylindrical main body, and a cutting edge formed on the ridges is divided by a plurality of dividing grooves. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5476590 [Patent Document 2] Patent No. 7465980 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, a peripheral cutting edge is formed in addition to a tip cutting edge in order to perform hole drilling of composite materials, but it cannot be used for side machining, etc., like an end mill, and is only equipped with a hole drilling function. Also, in Patent Document 2, although it has a side machining function, etc., like an end mill, when used for hole drilling, it is difficult to remove chips from the hole, making it impractical.

[0007] With conventional cutting tools, it is difficult to give the drills used for hole drilling the same functionality as end mills. Although end mills are sometimes used for hole drilling, they have drawbacks in terms of processing stability and chip removal.

[0008] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a cutting tool that is capable of performing hole making like a drill and also capable of performing side machining and the like like an end mill. [Means for solving the problem]

[0009] The cutting tool according to the present invention is a cutting tool that rotates around an axis line, and includes a tip portion having a tip cutting edge formed thereon, and a main body portion connected to the rear end side of the tip portion and having a helical chip discharge groove formed around the axis line, and the main body portion has an outer peripheral cutting edge formed along a leading edge, and the inner surface of the chip discharge groove has a plurality of inner grooves on the rake face of the outer peripheral cutting edge. From the axis to the outer periphery The cutting edge is formed so as to incline toward the rear end and intersect with the outer peripheral cutting edge. Furthermore, the outer peripheral cutting edge is formed in a wavy curved shape so as to be recessed at the intersection with the inner groove. Furthermore, the inner groove is formed so as to expand toward the outer peripheral cutting edge and communicate with the adjacent inner groove. Furthermore, the inner groove adjacent to the tip cutting edge is formed by cutting out the tip cutting edge. Furthermore, the inner groove is deepened by gouging out the side edge on the rear end side to form a step. Effect of the Invention

[0010] The present invention has a tip portion formed with a tip cutting edge and a main body portion formed with a spiral chip discharge groove, so it can perform hole drilling like a drill, and has a peripheral cutting edge formed along the leading edge of the main body portion, so it can perform side machining like an end mill.

[0011] In addition, on the inner surface of the chip discharge groove, multiple inner grooves are formed on the rake face of the outer cutting edge, inclining toward the rear end and intersecting with the outer cutting edge. Therefore, chips introduced into the chip discharge groove are cut into small pieces by the inner grooves and smoothly discharged, making it possible to perform drilling and side machining efficiently. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view of the appearance of a cutting tool according to an embodiment of the present invention; [Diagram 2] 2A and 2B are a front view and a side view of the tip portion of the drill shown in FIG. [Diagram 3] 3 is a cross-sectional view taken along line AA and line BB in FIG. 2. [Figure 4] FIG. 2 is an enlarged view of a tip portion of the cutting tool shown in FIG. [Diagram 5] FIG. 11 is an explanatory diagram showing a case where a hole is drilled by a cutting tool. [Figure 6] FIG. 11 is an explanatory diagram showing a case where side surface machining is performed by a cutting tool. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present invention will be described in detail. Note that the embodiments described below are preferred examples for carrying out the present invention, and therefore various technical limitations are imposed thereon, but the present invention is not limited to these embodiments unless otherwise specified in the following description to limit the present invention.

[0014] Fig. 1 is a perspective view of the appearance of a cutting tool 1 according to an embodiment of the present invention. Fig. 2 is a front view (Fig. 2(a)) and a side view (Fig. 2(b)) of the tip portion of the drill shown in Fig. 1.

[0015] The cutting tool 1 is configured to perform cutting processing while rotating around an axis TT, and includes a tip portion 10 having a pair of tool tip cutting edges 11 formed thereon, a main body portion 20 connected to the rear end side of the tip portion 10 and having a spiral chip discharge groove 21 formed around the axis TT, and a cylindrical shank portion 30 connected to the rear end side of the main body portion 20.

[0016] The tip portion 10 has a pair of tip cutting edges 11 formed radially around the axis TT, and is set at a predetermined tip angle with the center as the sharp point. A curved rake face is formed on the inside of the tip cutting edge 11 and communicates with the chip discharge groove 21, and a clearance face 12 is formed on the outside of the tip cutting edge 11 in a connected manner.

[0017] By pressing the tip 10 against a workpiece and rotating the cutting tool 1 around the axis TT, the tip cutting edge 11 cuts the workpiece to drill a circular hole.

[0018] The main body 20 has a pair of spiral chip discharge grooves 21 formed around the axis TT, which are connected to the cutting face of the tip 10 and have a predetermined width, so that chips generated by cutting at the tip cutting edge 11 are guided into the chip discharge grooves 21 and move toward the rear end side to be discharged to the outside.

[0019] An outer peripheral cutting edge 23 is formed on a leading edge 22, which is one end edge portion of each of the pair of chip discharge grooves 21, and a margin 24 is formed with a predetermined width from the end edge. A plurality of inner grooves 25 are formed in a curved surface portion of the groove surface of the chip discharge groove 21, which serves as a rake surface of the outer peripheral cutting edge 23. The pair of outer peripheral cutting edges 23 are formed with their front ends abutting against the outer ends of the pair of tip cutting edges 11.

[0020] The inner groove 25 is formed so as to incline toward the rear end side and intersect with the outer cutting edge 23, and is formed so as to widen toward the outer cutting edge 23 so as to communicate with the adjacent inner groove 25 in the vicinity of the outer cutting edge 23. The outer cutting edge 23 is formed in a wavy curved shape with a recessed portion intersecting with the inner groove 25.

[0021] 3 is an AA cross-sectional view (FIG. 3(a)) and a BB cross-sectional view (FIG. 3(b)) of FIG. 2. The AA cross-sectional view is a cut surface perpendicular to the axis TT at a wavy peak portion of one of the pair of peripheral cutting edges 23 (the front side in FIG. 2), and the BB cross-sectional view is a cut surface perpendicular to the axis TT at a wavy valley portion. The pair of peripheral cutting edges 23 are formed such that the peak portions and valley portions of the wavy curved shape are offset from each other in the direction of the axis TT, and the peak portion of one peripheral cutting edge 23 is set to correspond to the valley portion of the other peripheral cutting edge 23.

[0022] Since the peaks and valleys of a pair of peripheral cutting edges 23 have corresponding shapes, when the cutting tool is rotated and the peripheral cutting edges 23 are used to cut the side of the workpiece, the areas that have been cut by the valleys are cut by the peaks, and by cutting the areas alternately by the peaks and valleys, the cut surface can be finished uniformly.

[0023] Each inner groove 25 is deepened at the side edge on the rear end side to form a step 25a, and becomes shallower toward the front end side to form a gently sloping surface. Figure 4 is an enlarged view of the tip portion of the cutting tool shown in Figure 1, and shows the shape of the inner groove 25 by gradation.

[0024] By forming the inner groove 25 in this shape, when chips generated by cutting by the outer cutting edge 23 are guided inside the chip discharge groove 21 toward the rear end, they move inside the inner groove 25 and come into contact with the step 25a, causing them to break off, and the chips are cut into small pieces, which can be efficiently moved inside the chip discharge groove 21 and discharged.

[0025] The inner groove 25 adjacent to the tip cutting edge 11 extends toward the tip cutting edge 11, and has a shape in which a part of the tip cutting edge 11 is cut out (see FIG. 2(a)). By forming a notch in the tip cutting edge 11, the tip portion 10 is restrained during cutting, and the tip portion 10 can rotate without shaking and perform a stable cutting operation.

[0026] In addition, chips generated by cutting by the leading cutting edge 11 are guided through the chip discharge groove 21 toward the rear end, and as they move within the inner groove 25, they come into contact with the step 25a, and the chips break into small pieces, allowing them to move efficiently within the chip discharge groove 21 and be discharged.

[0027] The pitch and curvature of the wavy curved shape of the outer cutting edge 23 can be adjusted as appropriate according to the processing conditions such as the material of the workpiece. Similarly, the pitch and shape of the inner groove 25 can be changed as appropriate according to the processing conditions.

[0028] 5 is an explanatory diagram showing a case where a hole is drilled by a cutting tool. In the hole drilling process, a cutting tool 1 rotates around an axis TT while pressing a tip end of the cutting tool 1 against a surface of a workpiece M to form a hole H.

[0029] The rotating tip cutting edge 11 performs cutting action by pressing the tip of the cutting tool 1 against the surface of the workpiece M. The chips generated by the cutting action are guided toward the rear end side in the chip discharge groove 21 as shown by the arrow.

[0030] When the chips move in the chip discharge groove 21, they move in the inner groove 25 and come into contact with the step 25a, and the chips are broken into small pieces and efficiently discharged. This makes it possible to perform the hole drilling process stably and efficiently.

[0031] 6 is an explanatory diagram showing a case where side surface machining is performed by a cutting tool. In side surface machining, the cutting tool 1 rotates around the axis line TT while pressing the main body against the surface to be machined of the workpiece M, and moves along the surface to be machined to form a side surface P.

[0032] The cutting tool 1 rotates while pressing the outer cutting edge 23 against the surface to be machined of the workpiece M, and the cutting action is performed by the outer cutting edge 23. The chips generated by the cutting action are broken at the peaks and valleys due to the wavy curved shape of the outer cutting edge 23. Then, when the broken chips move inside the chip discharge groove 21, they move inside the inner groove 25 and come into contact with the steps 25a, and the broken chips are broken into small pieces and efficiently discharged. This makes it possible to perform side machining stably and efficiently. [Industrial Applicability]

[0033] The present invention can perform hole drilling like a drill with the tip part having a tip cutting edge, and can perform side machining like an end mill with the peripheral cutting edge formed along the leading edge of the main body. Therefore, cutting processes that have been performed with multiple cutting tools such as drills and end mills can be performed with a single cutting tool, shortening the processing time compared to conventional methods and greatly improving work efficiency. [Explanation of symbols]

[0034] 1 cutting tool, 10 tip portion, 11 tip cutting edge, 12 flank face, 20 main body portion, 21 chip discharge groove, 22 leading edge, 23 peripheral cutting edge, 24 margin, 25 inner groove, 25a step, 30 shank portion

Claims

1. A cutting tool that rotates around an axis, comprising: a tip portion having a leading cutting edge formed thereon; and a main body portion connected to the rear end side of the tip portion and having a spiral chip discharge groove formed around the axis, wherein an outer peripheral cutting edge is formed along the leading edge of the main body portion, and the inner surface of the chip discharge groove has a plurality of inner grooves formed on the rake face of the outer peripheral cutting edge, inclined from the axis side toward the rear end toward the outer periphery side, so as to intersect with the outer peripheral cutting edge.

2. The cutting tool according to claim 1 , wherein the outer cutting edge is formed in a wavy curved shape so as to be recessed at an intersection with the inner groove.

3. The cutting tool according to claim 1 or 2, wherein the inner groove is formed so as to widen toward the outer cutting edge and communicate with an adjacent inner groove.

4. The cutting tool according to claim 1 or 2, wherein the inner groove adjacent to the tip cutting edge is formed by cutting away the tip cutting edge.

5. 3. The cutting tool according to claim 1, wherein the inner groove is deepened at a side edge on a rear end side so as to be carved out, forming a step.

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