JP2015188951A - Cutting tool with coolant hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool with a coolant hole capable of stably supplying coolant toward a blade section by smoothing split flows from a trunk passage of the coolant to a branch passage.SOLUTION: A cutting tool 1A with a coolant hole supplies coolant from a coolant hole 10 formed in a tool body 2 toward a blade section 3a. The coolant hole 10 includes a bottomed hole-shaped trunk passage 11 extending along an axis O direction of the tool body 2 and a plurality of branch passages 15 which are opened in the blade section 3a and are communicated with the trunk passage 11. The branch passages 15 are opened on at least a bottom surface 13 in the trunk passage 11.

Description

  The present invention relates to a cutting tool with a coolant hole.

  Conventionally, for example, a cutting tool with a coolant hole for supplying coolant (oil-based or water-soluble cutting agent) from a coolant hole formed in a tool body toward a blade portion as shown in, for example, the following Patent Document 1 is known. Yes. The cutting tool with a coolant hole of Patent Document 1 is an end mill with a coolant hole in which a coolant hole is formed in an end mill body.

Specifically, the coolant hole has a main road extending along the axial direction of the tool body, and a plurality of branches that open to the blade portion and communicate with the main road. The plurality of branches are open to the chip discharge groove.
And at the time of a cutting process, a coolant is supplied toward the inside of a trunk path from the spindle etc. of the machine tool which supports the base end part of a tool main body. The coolant flows in the main road from the proximal end to the distal end side of the tool main body, and after being divided into a plurality of branches, is jetted toward the blade portion.

  In the end mill with coolant holes described in Patent Document 1 (see FIG. 6 of Patent Document 1), a plurality of branches are opened on the inner peripheral surface of the trunk, and these branches and the trunk are in communication with each other. Yes. Therefore, the coolant supplied to the tool main body flows in the main road, and is sequentially divided into a plurality of branches from the inner peripheral surface of the main road.

  Further, in the conventional example shown in FIG. 7 attached to the present specification, the coolant hole 100 has a main path 101 and a plurality of branch paths 105. The plurality of branch paths 105 are opened at the bottom of the inner peripheral surface of the main path 101 (the lower end of the inner peripheral surface of the main path 101 in FIG. 7) and arranged in the circumferential direction around the axis O. Yes.

JP-A-4-240014

  However, in the conventional cutting tool with a coolant hole, the coolant did not flow smoothly in the vicinity of the bottom surface of the main road. In other words, in the vicinity of the bottom of the main road, the coolant hits the bottom and does not flow smoothly into the branch, making it easy to generate turbulent flow, preventing smooth diversion of coolant from the main road to each branch. It was.

  Specifically, in the conventional example shown in FIG. 7, the coolant flowing in the coolant hole 100 toward the front end side in the axis O direction (downward in FIG. 7) is near the bottom surface of the trunk road 101 (branch with the branch path 105). It collides with the bottom surface (below the part), and turbulence tends to occur near the bottom surface. Such a turbulent flow hinders a smooth diversion from the main path 101 to the branch path 105.

  If the smooth flow of the coolant from the main road to the branch road is hindered, it becomes difficult to stably supply the coolant toward the blade portion. If the coolant cannot be stably supplied to the blade portion, the chip discharging performance and wear resistance of the cutting tool are lowered, and the influence on the machining accuracy and the shortening of the tool life become problems.

  The present invention has been made in view of such circumstances, and provides a cutting tool with a coolant hole that can smoothly distribute coolant from a main path to a branch path and stably supply coolant toward a blade portion. The purpose is to do.

In order to solve such problems and achieve the above object, the present invention proposes the following means.
That is, the present invention is a cutting tool with a coolant hole for supplying coolant from a coolant hole formed in a tool body toward a blade portion, and the coolant hole extends along an axial direction of the tool body. It has a hole-shaped trunk and a plurality of branches that open to the blade and communicate with the trunk, and the branches open at least on the bottom surface of the trunk.

  According to the cutting tool with a coolant hole of the present invention, the branch branching from the main road opens to the bottom surface of the main road, so that the coolant stays near the bottom surface of the main road or generates turbulent flow. Is suppressed. That is, the coolant flowing in the main road from the base end to the front end side of the tool body is not uniformly abutted (collised) against the entire bottom surface when reaching the bottom surface of the main road, At least a part or more thereof is directly allowed to flow into the branch opening in the bottom surface.

  Thereby, it is suppressed that a coolant retains or produces a turbulent flow in the vicinity of the bottom surface of the main road, and the coolant is easily diverted smoothly toward the branch. Further, the coolant smoothly flowing into the branch is ejected from the opening of the branch to the blade portion with high accuracy. Therefore, lubrication and cooling of the blade portion and chip discharge are facilitated.

As described above, according to the present invention, it is possible to smoothly supply the coolant to the blade portion by smoothly dividing the coolant from the main path to the branch path. And this cutting tool with a coolant hole can improve chip | tip discharge | emission property, abrasion resistance, etc., can improve a processing precision, and can extend a tool life.
In the present invention, it is only necessary that at least one of the plurality of branches is opened at least on the bottom surface of the trunk road, and the above-described effects can be obtained. Furthermore, it is desirable that two or more or all of the plurality of branches are opened at least on the bottom surface of the trunk road, so that the above-described operational effects become more remarkable.

  In the cutting tool with a coolant hole of the present invention, the plurality of branches may be arranged in a circumferential direction around the axis.

In this case, a plurality of branches are arranged and opened in the tool circumferential direction on the bottom surface of the main road, and for example, it is easy to set the intervals between these branches at equal intervals. Therefore, the coolant diverting from the main road to the branch is likely to flow equally into each branch. For example, even when a plurality of cutting edges are provided on the blade portion, the coolant is evenly supplied to each cutting edge. The coolant can be supplied stably.
When a plurality of cutting edges are provided at unequal intervals in the tool circumferential direction, for example, the branch opening at the bottom surface of the main road can be made by varying the inclination angle of each branch with respect to the tool radial direction. The paths can be arranged at equal intervals, and the above-described effects can be obtained.
Moreover, you may arrange | position the several branch opening opened to the bottom face of a trunk road at an irregular interval in the tool circumferential direction.

  In the cutting tool with a coolant hole of the present invention, the plurality of branches may be in communication with each other in the circumferential direction on the bottom surface.

  In this case, on the bottom surface of the main road, an annular opening formed by communicating a plurality of branches in the tool circumferential direction (hereinafter referred to as an annular opening), and a bottom center portion surrounded by the annular opening, Is formed. The center of the bottom surface surrounded by the annular opening on the bottom surface of the main road can be reduced in area, so that the coolant hits the bottom surface (from the base end of the tool body along the axial direction to the tip side (blade side)) The coolant collides with the bottom surface).

  Further, in the above-described configuration of the present invention, the cross-sectional area (cross-sectional area perpendicular to the axis) increases from the bottom surface of the main road toward the tool front end side as it goes from the bottom center of the main road to the tool front end. A coolant guide portion having a substantially frustum shape or a substantially frustum shape (substantially truncated cone shape) whose cross-sectional area increases as it goes from the center of the bottom surface of the main road toward the tip of the tool is formed. Therefore, the coolant flows smoothly from the main road into the branch along the outer periphery of the coolant guide portion.

  Further, in the cutting tool with a coolant hole of the present invention, the bottom surface is formed with an annular opening formed by communicating the plurality of branches with each other, and the bottom surface of the bottom surface is surrounded by the annular opening. The ratio of the area to the area of the cross section perpendicular to the axis of the trunk road may be 30% or less.

In this case, the ratio of the area of the center of the bottom of the main road to the area of the cross section of the main road is reduced to 30% or less, so the coolant flowing in the main road hits the bottom of the main road. Even so, the occurrence of turbulent flow is sufficiently suppressed, and the coolant flows smoothly toward the tool tip side of the bottom surface of the trunk and flows into the branch. Furthermore, the coolant can flow smoothly not only when flowing from the main road into the branch but also after flowing into the branch.
Specifically, when the ratio of the area of the center of the bottom surface of the main road to the area of the cross section of the main road exceeds 30%, turbulence may occur in the coolant near the bottom of the main road.

  According to the cutting tool with a coolant hole of the present invention, the branch branched from the trunk opens to the bottom of the trunk, so that the coolant is directed toward the branch without causing turbulence near the bottom of the trunk. Divide smoothly. Therefore, the coolant can be stably supplied toward the blade portion.

It is a perspective view which shows the cutting tool with a coolant hole which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view (cross-sectional view including the axis line of a tool main body) of the cutting tool with a coolant hole of FIG. It is a figure which expands and shows the principal part of FIG. It is a cross-sectional view (cross-sectional view perpendicular to the axis of the tool body) showing the main part of the cutting tool with a coolant hole, (a) PP cross section, (b) QQ cross section, (c) R in FIG. Represents the shape of each coolant hole in the -R cross section. It is a longitudinal cross-sectional view which expands and shows the principal part of the cutting tool with a coolant hole which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the principal part of the cutting tool with a coolant hole which concerns on 3rd Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the communication part of the main path of a coolant hole, and a several branch in the conventional cutting tool with a coolant hole.

(First embodiment)
Hereinafter, a cutting tool with coolant hole 1A according to a first embodiment of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, the cutting tool with coolant hole 1 </ b> A of the present embodiment is a radius end mill with coolant holes.

  The cutting tool 1A with a coolant hole has a tool body 2 having an axial shape. Specifically, the tool main body 2 has a substantially cylindrical shape, and a blade portion 3a is formed at least at the tip portion along the axis O direction of the tool main body 2. A portion other than the blade portion 3a is formed with a shank portion 3b. Has been.

  In the cutting tool with coolant hole 1A, a cylindrical shank portion 3b in the tool body 2 is gripped by a spindle of a machine tool or the like and rotated in a tool rotation direction T around an axis O, so Used for cutting (turning) of cutting materials. Further, along with the above rotation, a feed is given in the direction intersecting the axis O, and the cutting portion 3a performs face cutting, shoulder cutting, grooving and the like on the workpiece.

  Here, in the present specification, of the direction of the axis O of the tool body 2, the direction toward the blade portion 3a is the tip side (tool tip side), and the direction toward the opposite side of the blade portion 3a (to the shank portion 3b side). The direction of heading is called the base end side (tool base end side). A direction orthogonal to the axis O is referred to as a radial direction (tool radial direction), and a direction around the axis O is referred to as a circumferential direction (tool circumferential direction). Of the circumferential directions, the direction in which the tool body 2 is rotated during cutting is referred to as the tool rotation direction T (or the front of the tool rotation direction T), and the direction toward the opposite side of the tool rotation direction T is the tool rotation. It is called the rear of the direction T.

On the outer periphery of the blade portion 3a, a plurality of chip discharge grooves 4 are formed at intervals in the circumferential direction. The chip discharge groove 4 opens at the distal end surface of the tool body 2 and gradually twists and extends toward the rear in the tool rotation direction T from the distal end surface toward the proximal end side. In the cutting tool with coolant hole 1A of the present embodiment, the eight chip discharge grooves 4 are formed at intervals (equal intervals or unequal intervals) in the circumferential direction.
Each chip discharge groove 4 has a first wall surface facing the front in the tool rotation direction T and a second wall surface facing the rear in the tool rotation direction T.

An outer peripheral edge 6 is formed on each of the outer peripheral side ridges of the first wall surface of the chip discharge groove 4 (ridge lines extending along the outer peripheral edge of the first wall surface along the axis O direction). The first wall surface of the chip discharge groove 4 is a rake face of the outer peripheral blade 6.
The outer peripheral blade 6 is formed at the intersecting ridge line portion between the first wall surface facing the front in the tool rotation direction T of the chip discharge groove 4 and the outer peripheral flank 5 facing the radially outer side in the blade portion 3a.
Eight outer peripheral flank surfaces 5 are formed between the eight chip discharge grooves 4 on the outer peripheral surface of the blade portion 3a. The width of the outer peripheral flank 5 is substantially constant along the extending direction of the outer peripheral blade 6.

  In the blade portion 3a, eight outer peripheral blades 6 are formed at intervals in the circumferential direction. The eight outer peripheral blades 6 are leads equal to the eight chip discharge grooves 4 and gradually twisted and extended toward the rear in the tool rotation direction T toward the proximal end side of the tool body 2. A rotation trajectory formed by the eight outer peripheral blades 6 rotating around the axis O becomes one cylindrical surface centered on the axis O.

  A groove-like gash 7 is formed at the tip of the chip discharge groove 4 so as to cut out the first wall surface and the second wall surface of the chip discharge groove 4 inward in the radial direction. The gash 7 extends along the radial direction at the tip of the chip discharge groove 4, and the radially inner end is disposed in the vicinity of the axis O.

A bottom blade (tip blade) 9 is formed at the front edge side crest of the wall surface facing forward in the tool rotation direction T in the gash 7 (ridge line portion extending along the radial direction along the edge of the wall surface). Has been. The wall surface of the gash 7 is a rake face of the bottom blade 9.
The bottom blade 9 is formed at an intersecting ridge line portion between a wall surface facing the front in the tool rotation direction T of the gash 7 and a tip flank 8 facing the tip side in the blade portion 3a.
Eight tip flank surfaces 8 are formed between the tip portions (gash 7) of the eight chip discharge grooves 4 on the tip surface of the blade portion 3a. The width of the tip flank 8 gradually increases toward the outside in the radial direction.

In addition, the rotation trajectory formed by the eight bottom blades 9 rotating around the axis O is slightly slightly toward one base on the plane orthogonal to the axis O or gradually toward the inner side in the radial direction. It is located on one concave conical surface that is recessed.
The bottom blades 9 are arranged in a straight line and slightly behind the imaginary straight line extending in the radial direction passing through the axis O when the tip surface of the blade portion 3a is viewed from the direction of the axis O. ing. In other words, in the present embodiment, the bottom blade 9 is arranged in a core-lowering manner (see FIG. 1).

The bottom blade 9 is connected to the tip of the outer peripheral blade 6 through a convex curved corner blade, and the outer peripheral blade 6, the corner blade, and the bottom blade 9 form one L-shaped cutting blade. And is smoothly continuous.
The cutting tool with coolant hole 1 </ b> A having the eight-blade blade portion 3 a configured as described above is a so-called multi-blade radius end mill with coolant holes. The number of cutting blades (the number of sets of the continuous bottom blade 9, the corner blade, and the outer peripheral blade 6) is not limited to the eight blades of the present embodiment.

  As shown in FIGS. 2 and 3, a coolant hole 10 extending from the base end surface of the tool body 2 toward the distal end side is formed in the tool body 2. The coolant hole 10 opens on the outer surface (the tip surface and / or the outer peripheral surface of the blade portion 3a) of the tool body 2 so that the coolant can be supplied toward the blade portion 3a of the tool body 2. In the present embodiment, the coolant hole 10 opens at the tip surface of the blade portion 3a.

  The coolant hole 10 is a flow path through which coolant (oil-based or water-soluble cutting agent) flows. At the time of cutting, the coolant is supplied to the blade portion 3 a of the tool body 2 through the coolant hole 10. In the present embodiment, the coolant is ejected from the tip of the tool body 2, so that especially the bottom blade 9 in the blade portion 3 a is lubricated and cooled, and chips are discharged through the chip discharge groove 4 (gash 7). Inspired.

  The coolant hole 10 includes a bottomed hole-shaped trunk path 11 extending along the axis O direction of the tool body 2, and a plurality of branch paths 15 that open to the blade portion 3 a and communicate with the trunk path 11. Yes. The inner diameter of the branch path 15 is equal to or less than the inner diameter of the trunk path 11 (that is, the inner diameter is the same or smaller).

  The trunk path 11 is opened at the base end face of the tool main body 2 (shank portion 3b), and extends linearly from the base end face toward the tip end side blade section 3a along the axis O direction. The central axis of the trunk path 11 substantially coincides with the axis O of the tool body 2.

  In FIG. 3, the trunk road 11 has an inner peripheral surface 12 and a bottom surface 13. In the example shown in the figure, the bottom portion (tip portion in the direction of the axis O) of the trunk path 11 is located at the center of the blade portion 3a in the direction of the axis O. The trunk road 11 has a circular cross section (cross section) perpendicular to the axis O. That is, the inner peripheral surface 12 of the trunk road 11 has a circular cross section.

  The branch path 15 extends linearly from the trunk path 11 toward the distal end side, and is open at the distal end portion of the blade portion 3a in the illustrated example. Specifically, the branch path 15 of the present embodiment gradually extends outward in the radial direction from the main path 11 toward the distal end side, and is inclined with respect to the axis O. Further, the cross section of the branch 15 (a cross section perpendicular to the central axis of the branch 15) has a circular shape.

The branch 15 is open to at least the bottom surface 13 of the main road 11. Specifically, at least one of the plurality of branches 15 is open to at least the bottom surface 13 of the trunk path 11, and in the example shown in the present embodiment, all of the plurality of branches 15 are trunk paths. 11 is open to at least the bottom surface 13.
As shown in FIG. 3, in the present embodiment, the plurality of branches 15 are open only on the bottom surface 13 among the inner peripheral surface 12 and the bottom surface 13 of the trunk road 11.

In the present embodiment, eight branch roads 15 are branched from the main road 11. These branches 15 are arranged in the tool circumferential direction along the axis O.
The branch path 15 opens into the gash 7 at the distal end surface of the blade portion 3 a and opens (communication) to the bottom surface 13 of the trunk path 11. That is, the branch path 15 has a distal end side opening section 16 that opens to the blade section 3 a (the distal end face thereof) and a proximal end side opening section 17 that opens to the bottom surface 13 of the trunk path 11.

As shown in FIGS. 4A to 4C, in this embodiment, eight branches 15 are opened in the bottom surface 13 of the trunk road 11, and eight base end openings are formed in the bottom surface 13. A portion 17 is formed.
These proximal end side openings 17 may be arranged at equal intervals in the tool circumferential direction on the bottom surface 13 or may be arranged at unequal intervals. In the present embodiment, the base end side openings 17 of the plurality of branch paths 15 are arranged at equal intervals in the tool circumferential direction. Further, the proximal side openings 17 adjacent to each other in the tool circumferential direction communicate with each other, that is, the plurality of branch paths 15 communicate with each other on the bottom surface 13 in the tool circumferential direction.

  In addition, the bottom surface 13 is formed with an annular opening 18 so as to form an annular shape that surrounds the axis O by allowing the proximal end side openings 17 of the plurality of branch paths 15 to communicate with each other in the tool circumferential direction. Yes. In the present embodiment, a dot-shaped (top-shaped) bottom center portion 14 having an extremely small area is formed in a region surrounded by the annular opening 18 in the bottom surface 13.

  Further, the proximal end side opening portions 17 of the branch passages 15 communicate with each other, so that the blade portion 3a has a portion adjacent to the tool distal end side of the bottom surface 13 of the trunk path 11 toward the tool distal end side. A cone-shaped portion (including a substantially cone, a substantially pyramid, and other cone shapes) whose cross-sectional area (cross-sectional area perpendicular to the axis O) increases according to the shape is formed (see FIG. 3). The shape portion is a coolant guide portion 19 having the bottom surface central portion 14 as a top surface (vertex).

The coolant guide portion 19 has a top surface (vertex) and an outer peripheral surface. The top surface is a bottom surface central portion 14 of the bottom surface 13 formed so as to be cut out by a plurality of base end side openings 17, and the outer peripheral surface is a plurality of base end side openings connected to each other in the tool circumferential direction. 17 (inner peripheral surface).
Further, as shown in FIG. 4B, the outer peripheral surface of the coolant guide portion 19 protrudes outward in the tool radial direction and goes outward in the tool radial direction between the adjacent branch paths 15. Accordingly, a plurality of ridge portions (rib portions) 19a extending gradually toward the tool tip side are formed at intervals in the tool circumferential direction. The outer peripheral surface of the coolant guide portion 19 is inclined outward in the tool radial direction from the top surface (vertex) of the coolant guide portion 19 toward the tool tip side.
Further, as shown in FIG. 4C, the distal end side openings 16 of the plurality of branch paths 15 are separated from each other in the tool circumferential direction.

The coolant hole 10 configured in this manner acts as follows when the coolant is supplied to the tool body 2.
First, the coolant flows along the trunk path 11 from the base end surface of the cutting tool with coolant hole 1A toward the blade portion 3a. At this time, the coolant flows linearly toward the tool tip side.
Then, when the coolant reaches the bottom surface 13 of the trunk road 11, the coolant flows into the proximal end side opening portions 17 of the plurality of branch paths 15 that open to the bottom surface 13. That is, the coolant is diverted from the main road 11 to each branch 15.

At this time, since the proximal end side opening 17 of the branch path 15 is opened only in the bottom surface 13 of the trunk path 11, turbulent flow hardly occurs in the coolant that has reached the bottom surface 13.
Specifically, when the branch is configured to open only on the inner peripheral surface of the trunk as in the conventional case, the coolant that has reached the bottom surface of the trunk may return to the tool proximal side and flow into the branch. is there. For this reason, the coolant tends to be turbulent in the vicinity of the bottom surface of the main road.
In contrast, in the coolant hole 10 of the present embodiment, the coolant that has reached the bottom surface 13 of the trunk path 11 flows toward the tool tip side without returning to the tool base end side, and flows into each branch 15. It is supposed to be.

  According to the cutting tool with coolant hole 1 </ b> A of the present embodiment described above, the branch 15 that branches from the trunk 11 opens to the bottom surface 13 of the trunk 11, so that the coolant is the bottom 13 of the trunk 11. It is suppressed that it stagnates in the vicinity and produces a turbulent flow. That is, the coolant flowing in the main path 11 from the base end to the front end side of the tool main body 2 is uniformly abutted against the entire bottom surface 13 when it reaches the bottom surface 13 of the main path 11 (collision). ), At least a part of the flow is directly allowed to flow into the branch 15 opened in the bottom surface 13.

  Thereby, it is suppressed that a coolant retains or produces a turbulent flow in the vicinity of the bottom surface 13 of the main path 11, and the coolant is easily diverted toward the branch 15. Further, the coolant smoothly flowing into the branch 15 is jetted from the distal end side opening 16 of the branch 15 to the blade 3a with high accuracy. Therefore, lubrication and cooling of the blade portion 3a and chip discharge are facilitated.

As described above, according to the present embodiment, the coolant can be smoothly divided from the main path 11 to the branch path 15, and the coolant can be stably supplied to the blade portion 3a. And this cutting tool 1A with a coolant hole can improve chip | tip discharge | emission property, abrasion resistance, etc., can improve a processing precision, and can extend a tool life.
In the present invention, it is only necessary that at least one of the plurality of branches 15 is opened at least on the bottom surface 13 of the trunk road 11, thereby achieving the above-described effects. Further, two or more of the plurality of branches 15 or all of the plurality of branches 15 as described in the present embodiment are opened at least on the bottom surface 13 in the trunk path 11, so that the above-described effects can be further improved. It becomes exceptional and desirable.

Moreover, in this embodiment, since the several branch 15 is arranged in the tool circumferential direction, there exists the following effect.
In other words, in this case, a plurality of branches 15 are arranged and opened in the tool circumferential direction on the bottom surface 13 of the trunk path 11, and for example, it is easy to set the intervals between the branches 15 to be equal. Accordingly, the coolant that is diverted from the main path 11 to the branch paths 15 can easily flow into each branch path 15, and a plurality of cutting edges (bottom blades 9) are provided in the blade portion 3a as in the present embodiment. Even in such a case, the coolant can be supplied evenly and stably to each cutting edge.
Unlike the present embodiment, when a plurality of cutting edges are provided at unequal intervals in the tool circumferential direction, for example, with respect to the tool radial direction of each branch 15 (radial direction orthogonal to the axis O). By making the inclination angles different from each other, it is possible to arrange the branch passages 15 (base end side opening portions 17) opened in the bottom surface 13 of the trunk road 11 at equal intervals, and the above-described effects can also be obtained. .
Moreover, you may arrange the several branch 15 opened to the bottom face 13 of the trunk path 11 at unequal intervals in the tool circumferential direction.

Further, in the present embodiment, the plurality of branch paths 15 communicate with each other in the tool circumferential direction on the bottom surface 13, and thus have the following effects.
That is, in this case, on the bottom surface 13 of the trunk path 11, an annular opening (annular opening 18) in which a plurality of branches 15 communicate with each other in the tool circumferential direction, and the center of the bottom surface surrounded by the annular opening 18 Part 14 is formed. The bottom surface central portion 14 surrounded by the annular opening 18 in the bottom surface 13 of the main path 11 can reduce the area, and thus the coolant hits the bottom surface 13 (from the base end of the tool body 2 along the axis O direction). It is possible to sufficiently suppress the coolant from colliding with the bottom surface 13 toward the front end side.

  Specifically, in the present embodiment, the bottom surface 13 is formed with an annular opening 18 in which the eight proximal end openings 17 communicate with each other in an annular manner in the tool circumferential direction, and is surrounded by the annular opening 18. In addition, a dot-like (top-like) bottom center portion 14 having an extremely small area is formed on the bottom surface 13. For this reason, the coolant flows toward the tip of the tool without hitting (collision) with the bottom surface 13, that is, flows into the branch 15 without generating almost turbulent flow.

  Furthermore, in the above-described configuration of the present embodiment, a substantially cone whose cross-sectional area increases from the bottom surface 13 of the main path 11 toward the tool tip side, with the bottom center portion 14 of the main path 11 as a vertex toward the tool tip side. Since the coolant guide portion 19 is formed, the coolant flows smoothly from the main path 11 into the branch path 15 along the outer periphery of the coolant guide portion 19.

(Second Embodiment)
Next, a cutting tool 1B with a coolant hole according to a second embodiment of the present invention will be described with reference to the drawings.
Note that detailed description of the same components as those in the above-described embodiment will be omitted, and only differences will be mainly described below.

As shown in FIG. 5, a coolant hole 20 is formed inside the cutting tool 1 </ b> B with a coolant hole. The coolant hole 20 includes the main path 11 and a plurality of branch paths 25.
These branches 25 are arranged in the tool circumferential direction inside the blade portion 3a. Each branch 25 opens to the bottom surface 13, and this opening portion serves as a proximal end side opening 27 of the branch 25.

Similar to the first embodiment, these branches 25 are opened only on the bottom surface 13 of the trunk path 11, and the same number of proximal-side openings 27 as the branches 25 are formed on the bottom surface 13.
Further, the proximal end side openings 27 of the branch paths 25 adjacent to each other in the tool circumferential direction communicate with each other, that is, the plurality of branch paths 25 communicate with each other on the bottom surface 13 in the tool circumferential direction.

  In addition, the bottom surface 13 is formed with an annular opening 28 so as to form an annular shape that surrounds the axis O by connecting the base end side openings 27 of the plurality of branch paths 25 to each other in the tool circumferential direction. Yes. In the present embodiment, a bottom center portion 24 having a predetermined area is formed in a region surrounded by the annular opening 28 in the bottom surface 13. The bottom center portion 24 of the present embodiment is surrounded by eight base end side openings 17 (annular openings 18), and is formed in a star-shaped octagonal plane.

  Further, the proximal end side opening portions 27 of the branch passages 25 communicate with each other, so that the blade portion 3a has a portion adjacent to the tool tip side of the bottom surface 13 of the trunk path 11 toward the tool tip side. A frustoconical shape (including a truncated cone, a truncated pyramid, and other truncated cone shapes (that is, a truncated cone shape)) is formed. The coolant guide portion 29 has the portion 24 as a top surface (vertex).

  When the coolant flows through the coolant hole 10 and diverts from the main path 11 to the branch path 25, the coolant may hit the bottom surface central portion 24 to generate a turbulent flow. Therefore, it is preferable that the bottom center portion 24 has an area as small as possible. Specifically, in the present embodiment, the ratio of the area of the bottom center portion 24 to the cross-sectional area of the trunk road 11 (the cross-sectional area perpendicular to the axis O) is 30% or less. Further, the diameter (outer diameter) of the bottom center portion 24 is, for example, 30% or less with respect to the inner diameter of the trunk path 11.

According to this embodiment, the same effect as the above-mentioned embodiment is obtained.
Moreover, in the coolant guide part 29 of this embodiment, it is easy to form the bottom face center part 24 used as a top face stably compared with the dotted | punctate bottom face center part 14 demonstrated in the above-mentioned embodiment. And since this coolant guide part 29 is formed in the substantially frustum shape (substantially truncated cone shape) where a cross-sectional area increases as it goes to the tool front end side by using the bottom surface central part 24 of the trunk road 11 as a top surface, Along the outer periphery of the coolant guide portion 29, the coolant flows smoothly from the main road 11 into the branch path 25.

Further, since the ratio of the area of the bottom center portion 24 of the main road 11 to the area of the cross section of the main road 11 is reduced to 30% or less, the coolant flowing in the main road 11 is Even if it hits the bottom surface 13, the occurrence of turbulent flow is sufficiently suppressed, and the coolant flows smoothly toward the tool tip side of the bottom surface 13 and flows into the branch 25. Furthermore, the coolant is likely to flow smoothly not only when flowing into the branch 25 from the trunk 11 but also after flowing into the branch 25.
Specifically, when the ratio of the area of the bottom center portion 24 of the trunk road 11 to the area of the cross section of the trunk road 11 exceeds 30%, turbulent flow is generated in the coolant near the bottom face 13 of the trunk road 11. There is a fear.

(Third embodiment)
Next, a cutting tool 1C with a coolant hole according to a third embodiment of the present invention will be described with reference to the drawings.
Note that detailed description of the same components as those in the above-described embodiment will be omitted, and only differences will be mainly described below.

As shown in FIG. 6, a coolant hole 30 is formed inside the cutting tool with coolant hole 1 </ b> C. The coolant hole 30 includes the trunk path 11 and a plurality of branch paths 35.
These branches 35 are arranged in the tool circumferential direction inside the blade portion 3a. Each branch 35 opens to at least the bottom surface 13, and this opening portion serves as a proximal end side opening 37 of the branch 35.

And the base end side opening part 37 of the branch path 35 of this embodiment is opened not only to the bottom face 13 but also to the inner peripheral face 12. That is, a part (inner peripheral part) of the base end side opening 37 is opened in the bottom surface 13, and the rest (outer peripheral part) is opened in the inner peripheral surface 12.
Further, the proximal end side openings 37 of the branch paths 35 adjacent to each other in the tool circumferential direction are in communication with each other, that is, the plurality of branch paths 35 are in communication with each other on the bottom surface 13 in the tool circumferential direction.

  In addition, an annular opening 38 is formed on the bottom surface 13 so as to form an annular shape that surrounds the axis O by causing the proximal end side openings 37 of the plurality of branch paths 35 to communicate with each other in the tool circumferential direction. Yes. A bottom surface central portion 24 having a predetermined area is formed in a region surrounded by the annular opening 38 in the bottom surface 13. The bottom surface central portion 24 of the present embodiment has the same shape as the bottom surface central portion 24 described in the second embodiment, and specifically, eight base end side openings 37 (annular openings 38). ) To form a star-shaped octagonal surface.

  Further, the proximal end side opening portions 37 of the branch passages 35 communicate with each other, so that the blade portion 3a has a portion adjacent to the tool distal end side of the bottom surface 13 of the trunk path 11 toward the tool distal end side. A frustoconical shape (including a truncated cone, a truncated pyramid, and other truncated cone shapes (that is, a truncated cone shape)) is formed. The coolant guide portion 29 has the portion 24 as a top surface (vertex).

By providing the base end side opening 37 formed from the bottom surface 13 to the inner peripheral surface 12, the area of the outer peripheral side region of the annular opening 38 in the bottom surface 13 can be made extremely small. Further, for example, by expanding the inner diameter of the branch path 35, it is possible to prevent the bottom surface 13 from existing outside the annular opening 38 in the tool radial direction.
As a result, the amount of coolant that abuts against the bottom surface 13 is reduced, turbulent flow is less likely to occur, and the coolant is likely to flow smoothly into the branch 35.

  As described above, the base end side opening 37 of the branch path 35 may be opened to a region including at least the bottom surface 13. Further, it is preferable that the area of the bottom surface 13 is reduced to reduce the amount of coolant that hits the bottom surface 13.

  According to this embodiment, the same effect as the above-mentioned embodiment is obtained.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the plurality of branch paths 15, 25, and 35 are communicated with each other in the tool circumferential direction on the bottom surface 13 of the trunk path 11, but the present invention is not limited to this. The branch paths 15, 25, and 35 may be arranged on the bottom surface 13 at intervals in the tool circumferential direction.

  In addition, although the bottom surface 13 of the trunk road 11 is formed with the bottom center portions 14 and 24 surrounded by the annular openings 18, 28 and 38, the present invention is not limited to this. That is, for example, the base end side openings 17, 27, and 37 of the branches 15, 25, and 35 are opened on the axis O in the bottom surface 13, and the bottom surface central portions 14 and 24 may not be formed.

  Moreover, although the above-mentioned embodiment demonstrated using the 8-mill blade end mill, the number of blades is not restricted to an eight-blade. Similarly, the number of branches 15, 25, and 35 of the coolant hole 10 is not limited to eight. In addition, although it is preferable that the branch paths 15, 25, and 35 are the same number as the number of blades, it is not limited to the same number.

  Further, the cross-sectional shape perpendicular to the extending direction of the trunk path 11 and the branch paths 15, 25, and 35 is not limited to a circular shape. That is, the cross-sectional shape of the coolant holes 10, 20, 30 may be a polygonal shape other than a circular shape, an elliptical shape, or the like. In addition, about each branch 15, 25, 35, it is preferable that it is mutually the same shape. As a result, the coolant flows evenly into the branches 15, 25, and 35, so that it is difficult for turbulent flow to occur in the coolant, and the coolant can be evenly supplied toward the blade portion 3a.

In the above-described embodiment, the tool body 2 is described using the solid type end mills 1A to 1C with coolant holes in which the cutting edges (the bottom edge 9 and the outer peripheral edge 6) are directly formed. However, the present invention is not limited thereto. Is not to be done. That is, the present invention can be appropriately used as long as it is a cutting tool with a coolant hole such as a drill, a reamer, and a miller in addition to the end mill.
Further, the cutting tool is not limited to a solid type (integrated type) cutting tool with a coolant hole. For example, a cutting tool of a head exchange type (a type in which a blade part and a tool body are assembled) or a cutting edge exchange type cutting tool (tool) The present invention can also be applied to a type in which an insert mounting seat is formed at the tip or outer peripheral portion of the main body, and a cutting insert having a cutting edge is detachably mounted on the insert mounting seat.

  In addition, in the range which does not deviate from the meaning of this invention, you may combine each structure (component) demonstrated by the above-mentioned embodiment, a modified example, a note, etc., addition of a structure, omission, substitution, others It can be changed. Further, the present invention is not limited by the above-described embodiments, and is limited only by the scope of the claims.

1A, 1B, 1C Cutting tool with coolant hole 2 Tool body 3a Blade part 10, 20, 30 Coolant hole 11 Trunk path 13 Bottom face 14, 24 Bottom face center part 15, 25, 35 Branch path 18, 28, 38 Annular opening O Axis

Claims (4)

A cutting tool with a coolant hole for supplying coolant from the coolant hole formed in the tool body toward the blade part,
The coolant hole is
A bottomed hole-shaped trunk extending along the axial direction of the tool body;
A plurality of branches that open to the blade and communicate with the main road;
The branch passage opens at least on the bottom surface of the main road, and has a coolant hole. A cutting tool with a coolant hole according to claim 1,
The cutting tool with a coolant hole, wherein the plurality of branches are arranged in a circumferential direction along the axis. A cutting tool with a coolant hole according to claim 2,
The cutting tool with a coolant hole, wherein the plurality of branches communicate with each other in the circumferential direction on the bottom surface. It is a cutting tool with a coolant hole of Claim 3,
On the bottom surface, the plurality of branches communicate with each other to form an annular opening,
With a coolant hole, the ratio of the area of the center of the bottom surface surrounded by the annular opening to the area of the cross section perpendicular to the axis of the main road is 30% or less Cutting tools.

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