JP2004291104A - Threading milling cutter and thread cutting tip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the chipping and favorably perform cutting work by finely dividing cutting chips even if cutting chips of workpieces are apt to run without being cut. <P>SOLUTION: This threading milling cutter is provided with a recessed part 40 in the central part of a cutting face of a projecting part of a recessed/projecting-shaped cutting blade 26 corresponding to a screw thread to be machined, and functioned as a chip breaker. Thus, the recessed part 40 curls and divides cutting chips formed by cutting not only the projecting tips but also the both side parts, suppresses the clogging and catching of the cutting chips even if the cutting chips of the workpieces are apt to run without being cut, prevents the chipping, and performs favorable screw cutting work. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thread milling machine, and more particularly to a thread milling machine which can finely cut a chip and perform a good cutting process even on a material to which the chip is easily connected.
[0002]
[Prior art]
2. Description of the Related Art A thread milling cutter provided with an uneven cutting edge corresponding to a thread to be machined on an outer peripheral portion is widely used for cutting a thread such as a female thread. The threading milling cutter described in Patent Document 1 is an example of such a tool. (A) A tool main body that is driven to rotate around an axis, and (b) is detachably attached to the tool main body and protrudes from the tool main body to the outer peripheral side. And a screw cutting tip provided with the above-mentioned concave and convex cutting edge at a tip end portion. FIG. 6 shows an example of a screw cutting tip. The screw cutting tip 100 has a substantially trapezoidal shape, and has an uneven shape on its long side, and a pair of cutting edges at both end edges in the plate thickness direction. 102 are provided. Further, in the vicinity of the cutting edge 102, a concave groove 104 inclined at a predetermined inclination angle ψ is formed along the long side of the trapezoidal shape so that the included angle of the cutting edge 102 is an acute angle of about 60 ° to 85 °. It is provided so that excellent sharpness can be obtained.
[0003]
[Patent Document 1]
Japanese Patent Publication No. Hei 8-11330
[Problems to be solved by the invention]
The concave groove 104 has an effect of curling or dividing the chip, but the cutting edge 102 has an uneven shape, and has a tip of a convex portion and both sides (a ridge line portion with a flank). However, since the chip generation mechanism is different, the concave groove 104 is only inclined as a whole from the tip of the convex portion (the tip of the chip 100). For chips that do not always have the appropriate curl and cutting action for chips that are easily connected, chipping may occur due to chip clogging or biting of elongated chips. was there.
[0005]
The present invention has been made in view of the above circumstances, and the purpose thereof is to suppress chipping by finely cutting chips even in a work material to which chips are easily connected, and to achieve excellent screw formation. It is to enable cutting.
[0006]
[Means for Solving the Problems]
In order to achieve such an object, a first invention is directed to a thread cutting mill in which an uneven cutting edge corresponding to a thread to be processed is provided on an outer peripheral portion, wherein a rake face of a convex portion of the cutting edge is provided. , Characterized in that a recess is provided at least along the side of the convex shape.
Note that the convex side portion is a ridge line where the rake face and the flank intersect.
[0007]
According to a second aspect of the present invention, in the thread milling cutter according to the first aspect, the recess is provided at a central portion of a rake face of a convex portion of the cutting edge.
[0008]
According to a third aspect of the present invention, in the thread milling cutter according to the second aspect of the present invention, the recess is provided so as to be gradually deeper continuously from the tip of the convex shape and the cutting edge present on both sides. .
[0009]
A fourth invention is the threading milling cutter according to any one of the first invention to the third invention, including a tool body that is driven to rotate around an axis, and a screw cutting tip that is detachably attached to the tool body. The thread cutting tip is provided with the concave and convex cutting edges and recesses.
[0010]
According to a fifth aspect of the present invention, a cutting edge having an uneven shape corresponding to a thread to be machined is provided at a tip portion which is detachably attached to a tool main body which is driven to rotate around an axis, and which protrudes from the tool main body toward an outer peripheral side. In the screw cutting tip described above, the rake face of the convex portion of the cutting edge is provided with a recess along at least the side of the convex shape.
[0011]
【The invention's effect】
In the thread milling cutter according to the first aspect of the present invention, since the rake face of the convex portion of the cutting edge is provided with a recess along the side of the convex shape, chips cut on the side are curled by the recess. As a result, the chip is prevented from clogging and biting even in a work material to which the chip is easily connected, and chipping is prevented, so that the screw can be cut well.
In addition, substantially the same operation and effect can be obtained in the fifth invention relating to the thread cutting tip.
[0012]
In the second aspect, since the concave portion is provided at the center of the rake face of the convex portion of the cutting edge, chips cut at the tip and both sides of the convex portion are curled by the concave portion. The chip is cut and clogged, and chipping is more effectively suppressed to prevent chipping, and, for example, a concave shape such as a U-shape is formed along the tip and both sides of the convex portion. The shape of the recess is simple and inexpensive compared to the case where a location is provided.
[0013]
In the third aspect of the present invention, since the concave portion is provided so as to become gradually deeper continuously from the convex tip and the cutting edge present on both sides, the cutting edge is sharpened, the sharpness is improved, and the sharpness is improved. Chips are more effectively curled and separated by the recesses provided continuously with the blade.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Although the thread milling cutter of the present invention is suitably used for cutting female threads, it is also possible to cut male threads. The tool body usually has a cylindrical shape or a tapered shape, and the unevenness of the cutting edge of the screw cutting tip may be one, but may be two or three or more. good. Although only one screw cutting tip may be provided, a plurality of cutting tips may be provided in the circumferential direction or the axial direction of the tool body.
[0015]
In addition, the thread milling machine may be one that cuts a thread groove only at the tip and both sides of a convex cutting edge, or may be one that cuts a screw thread by full-shape cutting including a concave part having an uneven shape.
[0016]
In the second invention, a concave portion is provided in the center of the convex portion, and the chips cut at the front end and both side portions of the convex shape are both curled and separated at the concave portion. For example, a concave portion having a U-shape or the like may be provided along the tip and both sides of the convex portion.
[0017]
In the third invention, the concave portion is provided so as to be gradually deepened continuously from the convex tip and the cutting edge present on both sides. However, in other embodiments, the convex tip and both sides are provided. A recess having a predetermined shape such as a square, a circle, an ellipse, or the like may be provided in a portion that enters a predetermined dimension inward from the cutting edge existing in the portion.
[0018]
In the thread milling cutter of the fourth invention, a thread cutting tip having a cutting edge is formed separately from a tool body. However, in other embodiments, a solid milling cutter provided with an uneven cutting edge is provided. Can also be applied.
[0019]
As for the screw cutting tip of the fifth invention, a concave portion is provided at the center of the convex portion as in the second invention, or the concave portion is continuously formed from the convex tip and the cutting edges existing on both side portions as in the third invention. Or a recess that gradually becomes deeper. A concave portion of a predetermined shape such as a square, a circle, an ellipse, etc. is provided in a portion that enters a predetermined dimension inward from the cutting edge present on the tip of the convex shape and both sides, or at the tip and both sides of the convex portion. It is also possible to provide a U-shaped recess or the like along.
[0020]
As the screw cutting tip, for example, it is also possible to adopt a groove provided with a concave groove as described in Patent Literature 1 and a cutting edge at the tip of the convex shape formed at an acute angle. Further, a recess may be provided. For various types of screw cutting, such as a screw-cutting tip with an approximately right-angled tip and a substantially rectangular cross-section, or a tip with a sharp-edged tip at both ends The present invention can be applied to a chip. In Patent Literature 1, cutting edges are provided at both ends in the thickness direction of a plate-shaped screw cutting tip, but the present invention relates to a screw cutting tip having a cutting edge provided only at one end in the thickness direction. May also be applied.
[0021]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1A and 1B are views showing a thread milling cutter 10 according to an embodiment of the present invention, wherein FIG. 1A is a front view seen from a direction perpendicular to an axis O, and FIG. In addition, a single screw cutting tip 14 is detachably attached to a tip portion of the cylindrical tool body 12 by an attachment bolt 16. The tool body 12 integrally includes a large-diameter shank 18 and a neck portion 20 in the axial direction. The shank 18 is gripped by a main shaft (not shown) and driven to rotate around the axis O. A recess 22 is formed in the portion, and a tip mounting seat 24 is provided. The screw cutting tip 14 is positioned in a position parallel to the axis O and is integrally fixed by the mounting bolt 16.
[0022]
FIGS. 2A and 2B are enlarged views each showing the screw cutting tip 14 alone. FIG. 2A is a front view, FIG. 2B is a right side view of FIG. 2A, and FIG. It is sectional drawing. The screw cutting tip 14 has a flat plate-like shape and a substantially trapezoidal shape, and is provided with a number of irregularities corresponding to the threads to be machined on the long side of the trapezoid, and ridge lines at both ends in the plate thickness direction. Are used as the cutting edges 26 and 28, respectively, and the tip mounting seats are provided in such a manner that the tips provided with the irregularities protrude from the tool body 12 to the outer peripheral side and are substantially parallel to the axis O. 24. Further, both end surfaces 30 and 32 continuous with the pair of cutting edges 26 and 28 are symmetrical at the same inclination angle θ so that the thickness becomes thinner from the front end portion provided with the uneven shape toward the rear end, that is, the short side of the trapezoid. The pair of cutting edges 26 and 28 are both acutely angled to the rear edge. The inclination angle θ is, for example, in the range of 0 ° <θ ≦ 10 °, and is about 5 ° in the present embodiment, and the cutting edge angles of both cutting edges 26 and 28 are both about 85 °.
[0023]
Of the end faces 30, 32, the portions near the cutting edges 26, 28 function as rake faces, and the portions of the rake faces located at the centers of the convex portions of the cutting edges 26, 28 have circular or elliptical shapes, respectively. Recesses 40, 42 are provided. The recesses 40 and 42 function as chip breakers for curling and cutting chips, and have a relatively shallow and smooth arcuate cross-sectional shape, and are present at the tips and both sides of the convex shape. It is provided in a part which enters inside by a predetermined dimension from the cutting edges 26 and 28.
[0024]
The screw cutting tip 14 is provided with an insertion hole 34 for inserting the mounting bolt 16 at the center, and the opening at both ends of the insertion hole 34 is perpendicular to the other end surfaces 32 and 30 respectively. Are provided symmetrically with respect to the center line of the plate thickness. Thus, the head of the mounting bolt 16 screwed vertically to the chip mounting seat 24 is in close contact with the tapered surface 36 or 38 while the other end surface 32 or 30 is in close contact with the chip mounting seat 24. The screw cutting tip 14 is firmly attached to the tool body 12 regardless of which of the cutting edges 26 and 28 is used. The head of the mounting bolt 16 is provided with a tapered surface corresponding to the tapered surfaces 36 and 38 so that the mounting bolt 16 can be tapered. FIG. 1 shows a case where cutting is performed using the cutting edge 26.
[0025]
Further, the tip mounting seat 24 is arranged in accordance with the inclination angle θ such that the rake angle α of the cutting edge 26 or 28 becomes a predetermined value when the screw cutting tip 14 is mounted on the tool body 12. It is provided at a predetermined inclination angle β. That is, the inclination angle β of the tip mounting seat 24 with respect to a straight line connecting the axis O and the outer peripheral edge of the tip mounting seat 24 is determined to be 2θ−α. The rake angle α is determined, for example, within a range of −10 ° ≦ α <0 °. In the present embodiment, the rake angle is about −5 °, and the inclination angle β is about 15 °.
[0026]
In such a thread milling cutter 10, concave portions 40 and 42 are provided at the center of the rake face of the convex portions of the cutting edges 26 and 28, and function as a chip breaker. In addition to the chips cut on both sides, the recesses 40 and 42 provide curling and cutting action, so that chips that are easily connected to the chips can be clogged or bitten. Sinking is suppressed, chipping is prevented, and the screw can be cut well.
[0027]
In addition, since the recesses 40 and 42 are provided at the center of the rake faces of the protruding portions of the cutting blades 26 and 28, for example, the U-shaped recesses are formed along the front end and both side portions of the protruding portions. The shapes of the recesses 40 and 42 are simple and inexpensive compared to the case of providing.
[0028]
Incidentally, the thread milling cutter 10 (the present invention) in which the concave portions 40 and 42 are provided in a number of convex portions of the cutting edges 26 and 28, respectively, and a comparative product in which the concave portions 40 and 42 are not provided. When the tool life was examined by performing thread cutting under the following processing conditions, the results shown in FIG. 3 were obtained. As is apparent from FIG. 3, according to the present invention, even for a work material (SUS304) to which chips are easily connected, chipping due to chip clogging or the like is suppressed, and a sufficient tool life can be obtained. Become like
(Processing conditions)
Female thread: M24 × 2.0 (tapped: 24 mm)
Prepared hole: φ22 × 25mm (through hole)
Work material: SUS304
Cutting speed: 20m / min
Feed: 0.05mm / t
Cutting oil: Water-soluble processing machine: Horizontal machining center [0029]
In the above embodiment, the rake angle α is about −5 °, and the inclination angles θ of the end faces 30 and 32 of the screw cutting tip 14 are about 5 °. However, the rake angle α is appropriately determined including positive. In addition, the inclination angle θ is appropriately determined including 0 ° (the cutting edge angle is 90 °).
[0030]
Further, in the above-described embodiment, the recesses 40 and 42 are provided in a portion that enters the inside by a predetermined dimension from the cutting edge 26 and 28 existing on the front end and the both sides of the convex shape, for example, as shown in FIG. It is also possible to provide a rectangular (trapezoidal) recess 44 that gradually and continuously becomes deeper from the convex tip 26a and both side portions 26b, 26c of the cutting edge 26. In this case, not only the tip 26a of the cutting edge 26 but also the side portions 26b and 26c are sharpened to improve the sharpness, and the chips 44 are further effectively provided by the recess 44 provided continuously to the cutting edge 26. Curled and split. 4A is a front view of the cutting edge 26 as viewed from the rake face side, FIG. 4B is a cross-sectional view taken along line BB in FIG. 4A, and FIG. 4C is a cross-sectional view taken along line CC in FIG. is there.
[0031]
FIG. 5 shows a case where the thread is cut by the full-form cutting including not only the concave portion 26d but also the concave portion 26d of the concave and convex cutting edge 26, and the concave portion gradually becomes deeper from the concave portion 26d. A groove 46 is provided continuously with the concave portion 44, and the chips chipped in the concave portion 26d are also well curled and divided by the concave groove 46.
[0032]
Although the embodiments of the present invention have been described in detail with reference to the drawings, this is merely an embodiment, and the present invention is embodied in various modified and improved forms based on the knowledge of those skilled in the art. Can be.
[Brief description of the drawings]
FIGS. 1A and 1B are views showing a thread milling machine according to an embodiment of the present invention, wherein FIG. 1A is a front view, and FIG. 1B is a sectional view taken along line BB in FIG.
FIGS. 2A and 2B are diagrams each independently showing a thread cutting tip attached to the thread milling machine of FIG. 1, wherein FIG. 2A is a front view, FIG. 2B is a right side view of FIG. It is CC sectional drawing in ().
FIG. 3 is a view showing the result of a tool life test performed by cutting a female thread using the product of the present invention of FIG. 1 and a comparative product having no recess.
FIG. 4 is a view showing another embodiment of the present invention, and is a view for explaining a recess provided on a rake face of a cutting edge, where (a) is a front view and (b) is B in (a). FIG. 3B is a cross-sectional view, and FIG. 3C is a CC cross-sectional view in FIG.
FIG. 5 is a view showing still another embodiment of the present invention, and is a view for explaining a recess provided on a rake face of a cutting edge, where (a) is a front view and (b) is a view in (a). FIG. 3C is a cross-sectional view taken along line BB, and FIG. 3C is a cross-sectional view taken along line CC in FIG.
6A and 6B are views showing an example of a conventional screw cutting tip, in which FIG. 6A is a front view, and FIG. 6B is a right side view of FIG.
[Explanation of symbols]
10: Threading milling cutter 12: Tool body 14: Tip for screw cutting 26, 28: Cutting edge 26a: Tip 26b, 26c: Side 40, 42, 44: recess

Claims (5)

In a thread milling cutter in which an uneven cutting edge corresponding to the thread to be processed is provided on the outer periphery,
A thread milling cutter characterized in that a concave portion is provided on at least a rake face of a convex portion of the cutting edge along a side portion of the convex shape. 2. The thread milling cutter according to claim 1, wherein the recess is provided at a central portion of a rake face of the convex portion of the cutting edge. 3. The thread milling cutter according to claim 2, wherein the concave portion is provided so as to be gradually deepened continuously from the tip of the convex shape and the cutting edges existing on both sides. It has a tool body that is driven to rotate about an axis, and a screw cutting tip that is detachably attached to the tool body, and the screw cutting tip is provided with the uneven cutting edge and the recess. The thread milling cutter according to any one of claims 1 to 3, characterized in that: Screw cutting, which is detachably attached to a tool body that is driven to rotate around an axis, and has an uneven cutting edge corresponding to a thread to be machined at a tip protruding outward from the tool body. In the chip for
A tip for screw cutting, wherein a concave portion is provided on at least a rake face of a convex portion of the cutting edge along a side portion of the convex shape.

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