JPH0337846Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a throw-away tip that is bonded to various indexable tools.

[Conventional technology]

In recent years, various types of cutters such as bits, face mills, drills, etc. can be used without the need for re-grinding, the cutter body can be used semi-permanently, and tool costs can be reduced. Due to its advantages, the throw-away method is increasingly being adopted.

By the way, conventionally, the throw-away tip used for this kind of cutting tool or cutter is as follows.
For example, those shown in FIGS. 1, 3, and 5 are known.

[The problem that the idea aims to solve]

However, none of these conventional throw-away tips has been found that simultaneously satisfies the machinability, cutting edge strength, and chip disposal properties that are particularly important for cutlery tools.

That is, the throw-away chip 1 shown in FIG. 1 is a so-called negative chip in which a rake face 2 and a flank face 3 are orthogonal to each other, and a cutting edge 4 consisting of a nose portion 4a and a straight portion 4b is formed at the intersection of these. It is.

In this indexable tip 1, since the rake face 1 and the flank face 2 are perpendicular to each other, the strength of the cutting edge 4 is high. As shown in FIG. 2, since it is necessary to provide a relief angle γ, the rake angle α becomes a negative rake angle by the amount of the relief angle γ, and therefore the machinability deteriorates. Note that in this case, the chips are continuous and the processability thereof is also poor.

In addition, the throwaway tip 1 shown in FIG.
This is a so-called positive chip in which the flank surface 3 is given a clearance angle γ in advance. As shown in Fig. 4, this throw-away tip 1 has good machinability because the rake angle α during cutting can be made a positive rake angle. As a result, the cutting edge angle β becomes smaller, and as a result, the strength of the cutting edge is significantly reduced, particularly at the nose portion 4a, which is the tip of the cutting edge 4, and the cutting edge is likely to be damaged. Note that, in this case as well, the chip disposability is poor as in the conventional example.

Furthermore, the throwaway tip 1 shown in FIG.
This is a chip with a chip breaker groove in which a chip breaker groove 5 is formed on the rake face 2 to make the rake angle α a positive rake angle in advance. Although this throw-away tip 1 has good cutting properties as in the conventional example described below, the strength of the cutting edge 4 is reduced. Also, in this case, since the chip breaker groove is formed, the chips can be broken up and the processing properties are good, but the cutting resistance increases because the chips are forcibly curled. Therefore, vibration is likely to occur, which, together with a decrease in the strength of the cutting blade 4, further promotes breakage of the cutting blade 4 portion.

This invention was made in consideration of the above-mentioned circumstances, and the object is to provide a throw-away tip that can simultaneously provide excellent cutting performance, cutting edge strength, and chip disposal performance.

[Means to solve the problem]

The feature of this device is that a convex spherical surface portion is formed on the peripheral edge of the rake face along the nose portion, which curves along a part of the virtual spherical body and intersects the flank surface in a convex curve. A convex curved line is formed at the nose part of the cutting blade by the intersecting ridge line with the flank surface, and this convex curved part creates a discontinuous part in the middle of the cutting blade where the direction in which the cutting blade extends discontinuously changes. The point is that it is formed.

[Effect]

With this throw-away tip, the rake angle of the convex spherical surface is small at the nose and gradually increases toward the inside of the rake face. The strength of the blade can be improved by increasing the blade angle of the blade.

In addition, the chips generated in accordance with the shape of the convex curved section are restrained by the convex curved section, so that the outflow direction is stabilized and the curling is also stabilized. When the chips are curled, tensile stress acts on both sides of the chips, causing them to crack and split. Furthermore, since the height of the convex spherical surface portion gradually increases from the nose toward the inside of the rake face, the separation of chips from the convex spherical surface portion is promoted, and the contact area between the chips and the convex spherical surface portion is greatly increased. This reduces cutting resistance and improves machinability. Furthermore, since the direction in which the chips extend discontinuously changes with the discontinuous part provided in the middle of the cutting edge as a boundary, this together with the spreading effect of the chips due to the above-mentioned convex spherical surface part causes a large tensile stress on the chips. acts, further promoting the separation of chips.

〔Example〕

An embodiment of this invention will be described below with reference to FIGS. 7 to 11.

The throw-away tip 11 has a triangular shape in plan view, and a cutting edge 14 is formed at the intersection of the rake face 12 and flank face 13.
This cutting edge 14 has a nose portion 14a and a straight portion 14b.
It is composed of. Further, one convex spherical surface portion 15 is formed at each nose portion 14a at the peripheral edge of the rake face 12. As a result, the nose portion 1 of the nose portion 14a and the straight portion 14b
A convex curved portion 14c having a convex arc shape in side view is formed in a portion adjacent to 4a. This convex curved portion 14c allows the cutting edge 1 to be located in the middle of the cutting edge 14.
A discontinuous portion is provided in which the extending direction of 4 changes discontinuously. That is, in the straight portion 14b, the cutting edge 14 extends in one direction, whereas in the convex curved portion 14c, the cutting edge 14 extends in one direction.
Since the extending direction of the cutting edge 14 changes continuously according to the curvature of the convex spherical surface portion 15, the cutting edge 14 changes continuously at the intersection between the straight line portion 14b and the convex curved portion 14c
The direction in which it extends is discontinuous.

The convex spherical surface portion 15 is curved along a part of the virtual sphere and has a shape that intersects the flank surface 13 in a convex curve, and the apex P of this virtual sphere is located at the rake face 12 in plan view. A bisector l ₁ that is outside of and divides the nose angle ε of the nose portion 14a into two equal parts.
is positioned above. Therefore, the convex spherical surface portion 1
5 is symmetrical about the bisector _l1 . Further, the height of the convex spherical surface portion 15 gradually decreases from the nose portion 14a toward the inside of the rake face 12. Moreover, since the convex spherical surface portion 15 is formed along a part of the virtual sphere, the contour line H becomes denser as it goes from the nose portion 14a toward the inside of the rake face 12, and therefore It gradually increases from the portion 14a toward the inside of the rake face 12.

In the throw-away chip having such a configuration, the rake angle of the convex spherical surface portion 15 is small at the nose portion 14a, and the rake angle from the nose portion 14a is small.
It gradually becomes larger as it goes inward. Therefore, it is possible to increase the blade angle of the nose portion 14a (blade edge portion), which is particularly prone to breakage, and to improve its strength without impairing good cutting performance.

When cutting is performed on this nose portion 14a, chips T having an arcuate cross section corresponding to the shape of the convex curved portion 14c are generated, as shown in FIGS. 9 and 10. Since the shape of the chips T corresponds to the convex curved portion 14c, the chips T are restrained by the convex curved portion 14c, so that the outflow direction is stabilized and the curling thereof is stabilized.

Further, due to the spreading action of the convex curved portion 14c, the chips T have a thinner shape in side view than if they were generated by a simple straight cutting edge. Moreover, when this chip T curls, both sides curl toward the outside of the curl circle, and the radius of curvature of both sides becomes larger than the radius of curvature of the central part, so there is a tensile stress on both sides of the chip T. acts, and this tensile stress causes the crack to separate from both sides. This chip separation and stable winding pattern combine to make the throw-away tip 11 have very good chip disposal properties.

In addition, in this throw-away tip 11, the rate at which the height of the convex spherical surface portion 15 decreases is not constant, but increases gradually from the nose portion 14c toward the inside of the rake face 12. The separation from the convex spherical surface portion 15 is promoted, and the contact area between the chips T and the convex spherical surface portion 15 is significantly reduced.
Therefore, cutting resistance is reduced, machinability is improved, and damage to the nose portion 14a can be further prevented.

Furthermore, as shown in FIG. 11, at the start of cutting, the work piece W gradually bites into the workpiece W from the top of the convex curved part 14c, and on the other hand, at the end of cutting, it gradually separates from the workpiece W from the top of the convex curved part 14c. Therefore, the impact at the start of cutting and at the end of cutting can be alleviated. From this point of view, the throw-away tip 11 is also suitable for interrupted cutting.

[Other Embodiments] Furthermore, this invention is not limited to the above-mentioned embodiments, and various modifications are possible. Next, such a modification will be explained.

FIG. 12 shows a structure in which the convex spherical surfaces 15 formed at each nose portion 14a are in contact with each other, and FIG. 13 shows a structure in which the convex spherical surfaces 15 intersect with each other. Further, FIG. 14 shows a case in which the nose portion 14a is an edge, FIG. 15 shows a case in which a clearance angle is given to the flank face 13 in advance, and FIG. 16 shows a case in which the nose portion 14a is a straight edge. Further, Figs. 17 to 19, Figs. 20 to 22, and Figs. 23 to 25 respectively show square, diamond-shaped, and hexagonal shapes.

Moreover, FIGS. 26 to 31 each show the state in which the throw-away tip 11 of any of the above-mentioned embodiments is mounted on a cutting tool body or a cutter body, etc., and cutting is being performed. The figure shows throwaway tip 1 shown in Fig. 20.
1 to the cutter body V, FIG. 27 shows the throw-away tip 11 shown in FIG. 17 to the cutter body C ₁ of a face milling cutter, and FIG. 28 shows the throw-away tip 11 shown in FIG. ₂
29 shows the throw-away tip 11 shown in FIG. 20 attached to the drill body D, FIG. 30 shows the throw-away tip 11 shown in FIG. 12 attached to the end mill body E, and FIG. 31 shows the throw-away tip 11 shown in FIG. A state in which the away chips 11 are respectively attached to the broach main body B and cutting is being performed is shown.

Note that the combination of these throw-away tips 11 and the cutting tool body V or cutter bodies C ₁ , C ₂ , etc. may be changed as appropriate, and it goes without saying that they may be combined with the throw-away tips 11 as described below. It is. Here, the second
When the throw-away tip 11 is attached to the groove milling cutter shown in FIG. 8 or the drill shown in FIG. Since the growth direction of the chips changes discontinuously depending on the part, the effect of further promoting the breakup of the chips can be obtained. That is, chips generated at the convex curved portion 14c of the cutting edge 14 grow so as to be spread out along the convex spherical surface portion 15, whereas chips generated at the straight portion 14b intersect with the straight portion 14b. Since the chips tend to grow almost straight in a certain direction, the direction of growth of the chips rapidly changes at the boundary between the straight portion 14b and the convex curved portion 14c of the cutting edge 14. Such a difference in the growth direction causes a large tensile stress that tears the chips laterally, and this stress is combined with the tensile stress generated as the convex spherical surface portion 15 pushes and spreads the chips, causing the chips to become more They are effectively divided.

Incidentally, the above-mentioned chip breaking effect can be similarly obtained even when the throw-away tip 11 is attached to the broach shown in FIG. 31, for example. Also,
Even in the case of the cutting tool shown in FIG. 10, the straight portion 14 is
A similar effect can be obtained if b is also involved in cutting. Furthermore, the discontinuous portion of the cutting edge 14 also has a convex curved portion 14.
Not limited to the boundary between c and the straight portion 14b,
For example, the same effect can be obtained even when the convex curved portions 14c are formed to cross each other as shown in FIGS. 12 and 13.

[Other Embodiments] Hereinafter, still other embodiments of this invention will be described. Note that the shape of the throwaway tip 11 itself, the spacing, contact, and intersection of the convex spherical surfaces 15 are the same as those described in any of the above embodiments, so to avoid duplication of explanation, only the characteristic points will be explained here. do.

The throwaway tip 11 shown in FIGS. 32 to 47 has one convex spherical surface portion 15 formed on each nose portion 14a, and the convex spherical surface portion 15 is as shown in FIG. 33. ,
The apex P of the virtual sphere forming the convex curved surface portion 15 is not on the bisector _l1 of the nose angle, and is asymmetrical with respect to this bisector _l1 . Such a throw-away tip 11 is used when it is easy to use, and the apex P is located on the user-friendly side.

[Other Embodiments] The throwaway tip 11 shown in FIGS. 48 to 63 has two convex spherical surface portions 15 formed on each nose portion 14a. 15 and 15 are formed by parts of the same virtual sphere, and the nose angle ε
intersects on the bisector l ₁ , so the bisector l
It is assumed to be symmetric with respect to l ₁ .

In such a throw-away tip 11, chips are generated by the respective convex spherical surfaces 15, 15, so that the chip disposal performance can be further improved.

In addition, the throwaway tip 1 shown in FIG.
No. 1 has a similar convex spherical surface portion 15 formed not only on the nose portion 14a of the cutting blade 14 but also on the straight portion 14b.

Further, in the throw-away tip 11 shown in FIG. 65, the convex spherical surface portion 15 is formed by parts of two virtual spheres having the same center in plan view and different radii of curvature.
That is, this convex spherical surface portion 15 is the nose portion 14a.
A part is formed by a part of a virtual sphere with a small radius of curvature, and a continuous part is formed by a part of a virtual sphere with a large radius of curvature, resulting in a two-stage shape. .

In each of the embodiments described above, the throwaway tip 11 has a polygonal shape in plan view, but is not limited to this, and may have a circular shape in plan view. Further, as the material for the throw-away tip, it is preferable to use cemented carbide, cermet, or the like.

Further, in the above embodiment, the convex spherical surface portion 15
is formed by a part of a virtual sphere, but is not limited to this, and may be formed by a part of another spherical body such as an ellipsoid. In addition, the convex spherical surface portion 1
The vertex P of the virtual sphere forming 5 may be located on the cutting edge 14, or may be located on the flank 13.
If a clearance angle is given to the cutting edge 14 in advance, the cutting edge 14 may be located slightly inside the cutting edge 14. moreover,
The radii of the virtual spheres forming each convex spherical surface portion 15 may be different from each other, or the heights of each convex spherical surface portion 15 may be different from each other. Note that it goes without saying that the number of convex spherical surface portions may be one.

[Effect of idea]

As explained above, the throw-away tip of this invention has a convex spherical surface curved along a part of the virtual spherical body at the peripheral edge of the rake face along the nose portion and intersecting the flank surface in a convex curve. form,
A convex curved portion is formed at the nose portion of the cutting blade by the intersecting ridge line of this convex spherical surface portion and the flank surface, and this convex curved portion makes the extending direction of the cutting blade indeterminate in the middle of the cutting blade. Since a discontinuous part is formed that changes continuously, it is possible to simultaneously obtain excellent cutting performance and chip disposability, and also to obtain sufficient cutting edge strength even at the nose part of the cutting edge, which is particularly prone to chipping. In addition, the cutting resistance can be reduced, and the impact on the cutting edge at the start and end of cutting can be alleviated. In particular, since the discontinuous portion is provided in the middle of the cutting edge, a greater chip breaking effect can be obtained compared to a case where the entire length of the cutting edge is made up of a uniform convex curved portion.

[Brief explanation of the drawing]

Figures 1, 3 and 5 each show an example of a conventional throw-away tip, with each figure A being a plan view, each figure B being a side view, and Figures 2, 4 and 6 being A partially cutaway side view showing the main part of the throw-away tip shown in Figures 1, 3, and 5 being mounted on a cutting tool and performing cutting, and Figure 7 is a side view of the throw-away tip of this invention. One embodiment of the chip is shown, FIG. 7A is a plan view, and FIG.
Figure B is a side view, Figure 8 is an enlarged plan view of the convex spherical surface of the throw-away tip shown in Figure 7, and Figure 9 is a cutting process in which the throw-away tip shown in Figure 7 is attached to a cutting tool. Fig. 10 is an enlarged perspective view showing the cutting situation on the convex spherical surface, Fig. 11 is a cutting with the throw-away tip shown in Fig. 7 attached to the cutting tool. A partially omitted side view showing the state at the start of cutting when machining is performed, and FIGS. 12 to 25 each show other embodiments of this invention, with each figure A being a plan view and each figure B being a side view. 26 to 31 respectively show a cutting tool or cutter equipped with a throw-away tip according to this invention, FIG. 26 is a partially omitted plan view showing the state of cutting by the cutting tool, and FIG. 27 is a front view. Partially omitted longitudinal sectional front view showing the state of cutting by a milling cutter, Fig. 28A
28B is a partially omitted side view of the groove milling cutter, FIG.
9A is a bottom view of the drill, FIG. 29B is a partially cutaway side view showing the main part of the drill in the state of cutting, and FIG.
Fig. 0 is a partially cutaway side view showing the main part of the cutting process with the end mill, Fig. 31 is a partially notched side view showing the cutting process with the broach with some parts omitted, and Figs. 32 to 47 Figures 48 to 65 respectively show still other embodiments of this invention, each figure A is a plan view, each figure B is a side view, and the third figure is a side view.
Figures 3 and 49 correspond to Figures 32 and 48, respectively.
FIG. 3 is an enlarged plan view of the convex spherical surface of the throwaway tip shown in the figure. 11... Throwaway tip, 12... Rake face, 13... Flank surface, 14... Cutting edge, 14a...
...Nose part, 14b...Straight line part, 14c...Convex curved part, 15...Convex spherical surface part, P...Vertex, l ₁ ...
bisector.

Claims (1)

[Claims for Utility Model Registration] (1) In a throw-away tip in which a cutting edge is formed with a nose portion at the intersection of a rake face and a flank face, an imaginary A convex spherical surface portion is formed that curves along a part of the spherical body and intersects with the flank surface in a convex curve, and the nose portion of the cutting blade is formed by an intersecting ridge line between the convex spherical surface portion and the flank surface. 1. A throw-away tip, characterized in that a convex curved portion is formed on the cutting edge, and a discontinuous portion is formed in the middle of the cutting edge by the convex curved portion, in which the direction in which the cutting edge extends discontinuously changes. (2) The throw-away tip according to claim 1, wherein a plurality of the convex spherical surface portions are formed. (3) The convex spherical surface portion is formed one on each of the nose portions, and the virtual spherical body forming the one convex spherical surface portion has an apex that is equal to the nose angle of the nose portion. Utility model registration claim 1, characterized in that the utility model is located on a bisector line and is symmetrical about the bisector line as a whole.
Throwaway tip as described in section. (4) The convex spherical surface portion is formed one on each of the nose portions, and the virtual spherical body forming the one convex spherical surface portion has an apex that is equal to the nose angle of the nose portion. The throwaway tip according to claim 1, which is a registered utility model, and is located offset from the bisector and is entirely asymmetrical with respect to the bisector. (5) Two convex spherical surface portions are formed on each of the nose portions, and these two convex spherical surface portions intersect on the bisector of the nose angle of the nose portion, and the two convex spherical surface portions intersect on the bisector of the nose angle of the nose portion, and The throw-away tip according to claim 1, which is arranged symmetrically with respect to the dividing line. (6) Utility model registration claims 1 to 5, characterized in that the virtual spherical body forming the convex spherical surface portion has its apex located outside the rake face in plan view. Throwaway tip described in any of the above. (7) Utility model registration claims 1 to 5, characterized in that the virtual spherical body forming the convex spherical surface portion has its apex positioned above the cutting edge in plan view. Throwaway tips listed in any of the above. (8) The convex spherical surface portion is formed such that adjacent portions are separated from each other, as described in any one of claims 2 or 5 to 7 of the utility model registration claim. Throwaway tip. (9) The convex spherical surface portion is formed such that adjacent portions are separated from each other, as described in any one of claims 2 or 5 to 7 of the utility model registration claim. Throwaway tip. (10) According to any one of claims 2 or 5 to 7 of the utility model registration claim, wherein the convex spherical surface portions are formed such that adjacent ones intersect with each other. Throwaway tips listed. (11) Utility model registration claim 2, characterized in that each of the convex spherical surface portions is formed with the same radius of curvature.
or the throw-away tip according to any one of paragraphs 5 to 10. (12) Utility model registration claim 2, characterized in that each of the convex spherical surfaces is formed with a radius of curvature that is different from each other.
or the throw-away tip according to any one of paragraphs 5 to 10. (13) Each of the convex spherical surface portions is formed such that the heights of the apexes of the virtual spherical body forming each of the convex spherical surface portions are equal to each other. section or section
Throwaway tip as described in any of Clause 12. (14) Each of the convex spherical surface portions is formed such that the heights of the apexes of the virtual spherical body forming each of the convex spherical surface portions are different from each other. Throwaway tip according to any one of Clauses 1 to 12.