JPH0698524B2 - Throw-away tip - Google Patents

Description

TECHNICAL FIELD The present invention relates to a throwaway chip suitable for use in a throwaway type drilling tool such as an end mill or a drill.

[Prior Art] For example, in various throw-away type drilling tools such as end mills and drills, the cutting edge formed on the ridge line of the upper surface is located on the tip side of the tool body. The plate-shaped throwaway tip (below,
It is abbreviated as a chip. ) Is detachably attached.

FIG. 12 to FIG. 16 show an example of a conventional chip mounted on a throwaway type end mill, which is a kind of the throwaway type drilling tool of this type.

The end mill body 1 of the throwaway end mill to which this chip is attached is formed in a substantially cylindrical appearance, and a tip pocket 2 is formed on the outer periphery of the tip end portion of which approximately half is cut off. Further, a rectangular concave chip seat 3 is formed on the outer peripheral side of the tip end portion of the wall surface forming the chip pocket 2, and at the center of the tip end portion, a core accommodating concave portion for accommodating a cylindrical core produced in a material to be cut accompanying cutting. 4 is bored along the axis O direction.

The above-mentioned conventional chip 5 is removably mounted on the chip seat 3 with a positive axial rake angle α.

The chip 5 is a parallelogrammatic plate having a lower surface 6 as a seating surface, and cutting edges 8, 9, 10, 11 are formed on each ridge of the upper surface 7. And this chip 5
Has a cutting blade 8 as a bottom blade on the tip side of the end mill main body 1, and cutting blades 9 and 10 located on the outer peripheral side and the inner peripheral side of the end mill main body 1 with the bottom blade 8 interposed therebetween, respectively. It is mounted as an outer peripheral blade and an inner peripheral blade.

When axial cutting is performed by a slow-away type end mill equipped with such a chip 5, an annular groove is cut and formed in a material to be cut by a cutting blade 8 which is a bottom blade of the chip 5. Therefore, a cylindrical core whose radius is the distance from the axis O to the inner peripheral side end of the cutting blade 8 is generated in the portion of the work material located at the center of rotation of the end mill body 1. When the end mill is fed in the direction of the axis O, the core relatively grows and is housed in the core housing recess 4, and when it is laterally fed, it is scraped off by the cutting blade 10 which is an inner peripheral blade of the chip 5. go.

[Problems to be Solved by the Invention] However, in the above-described conventional chip 5, as shown in FIGS. 13 and 14, the radial rake at the cutting edge 9 serving as the outer peripheral edge of the end mill body 1 is provided. If the angle is set to a positive angle and then attached with a positive axial rake angle α, the amount of back metal shown by H in the figure becomes small, so the tool rigidity of this end mill body 1 itself decreases,
As a result, it becomes impossible to endure a large cutting resistance.

Therefore, in order to secure a large back metal amount H, this chip 5 is attached to the upper surface 7 of the end mill body 1 in FIG.
When the radial rake angle of the cutting edge 9 that is the outer peripheral edge is set to a negative value as shown in FIGS. The radial rake angle β in the portion 10a becomes extremely large in the positive direction, and as a result, the flank 15 at the tip portion 10a of the cutting edge 10 enters the rotation locus X of the cutting edge 10, so-called second. There was a problem of hitting.

Therefore, if the tip clearance angle of the cutting edge 10 is set to a large value in advance to avoid the second hit at the tip 10a of the cutting edge 10, the cutting edge strength is significantly deteriorated, and as a result, the cutting edge 10 is When used as an outer peripheral blade under severe cutting conditions, there was a problem that the cutting edge was damaged and it could not be used.

Therefore, if the clearance angle at the cutting edge 10, which is the inner peripheral blade, is set to be large enough to avoid a second hit, and the clearance angle at the cutting edge 9 that is the outer peripheral blade is left unchanged, the cutting edge 10
Since the chip clearance angle between the cutting side and the cutting edge 9 side is different,
There is a problem that it is uneconomical because it becomes impossible to rotate the chip 5 by 180 ° and use the cutting edge 10 as the outer peripheral edge and the cutting edge 9 as the inner peripheral edge.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it is possible to secure a large amount of back metal on the tool body side without deteriorating the strength of the cutting edge, even if a positive axial rake angle is given and mounted. The purpose is to provide a chip that can be made.

[Means for Solving Problems] In the throw-away tip of the present invention, the thickness of the upper and lower surfaces is gradually increased from the central portion side of the upper surface toward the tip of the corner portion of the upper surface. The inclined surface and the stepped portion that are inclined from the inclined surface at a gentler inclination angle than the inclined surface or that extend parallel to the lower surface and reach the tip of the corner portion. Each of the two cutting blades sandwiching the corner portion is continuously provided in a range from one to the other.

[Operation] According to the above configuration, a large clearance angle of the throw-away tip at the tip of the inner peripheral blade is secured even when the tool body is mounted to give the throw-away tip a positive axial rake angle. Therefore, it is not necessary to give the seating surface of the tool body a very large axial rake angle.

[Embodiment] FIGS. 1 to 9 show an example of the chip of the present invention.

In FIGS. 1 to 5, the chip 20 has upper and lower surfaces 21, 22.
Are parallel-parallelepiped-shaped and have a lower surface 22 as a seating surface, and cutting edges 23, 24, 25, 26 are formed on each ridge of the upper surface 21, respectively.

In the chip 20, the obtuse angled corners of the upper surface 21 are inclined surfaces in which the thickness between the upper and lower surfaces 21, 22 gradually decreases from the center side of the upper surface 21 toward the tip side of each corner. 2
7 and 28, and step portions 29 and 30 extending from these inclined surfaces 27 and 28 in parallel with the lower surface 22 and reaching the tips of the respective corner portions. The reference numeral 31 in the drawing engages with the convex portion formed on the chip mounting seat of the end mill body 1 to respectively cut the above-mentioned cutting edge.
It shows a groove portion in which contact surfaces 31a and 31b with which the end mill body 1 is subjected to a feed force of cutting by the cutting edge 24 and the cutting edge 25 are formed.

As shown in FIGS. 6 and 7, the chip 20 is mounted on the end mill body 1 with its cutting edge 23 positioned on the tip side as a bottom edge. Here this chip 20
Is mounted on the end mill main body 1 with a positive radial rake angle α after the radial rake angle at the cutting edge 24, which is an outer peripheral blade, is made negative in order to obtain a large back metal amount H _1. .

In the chip 20 having such a configuration, as shown in FIGS. 8 and 9, even when the radial rake angle of the cutting edge 24 which is an outer peripheral edge is set to be negative, Since the corner portion of the upper surface 21 near the tip portion 25a of the cutting blade 25 which is a peripheral blade is formed by the inclined surface 27 and the step portion 29, the radial rake angle at the tip portion 25a of the cutting blade 25 is large. It never becomes a value.

Therefore, when taking large Batsukumetaru amount H ₁ of the end mill body 1 also, without increasing the chip clearance angle at the tip portion 25a of the cutting edge 25 which is an inner peripheral edge,
Because you can avoid the so-called second hit,
High cutting edge strength can be obtained over the entire length of the cutting blade 25.

Further, since the step portions 29 and 30 substantially parallel to the lower surface 21 are formed between the inclined surfaces 27 and 28 of the corner portions and the tips of the corner portions, the chip thickness at the tip of each corner portion is extremely small. It is possible to prevent thinning. This allows the cutting edge 23
Even when ~ 26 are used up to their respective ends, there is no risk of causing damage to the ends of each cutting edge.

In addition, these corners together with the inclined surfaces 27 and 28 and the step portion 29,
By forming with 30 and the chip 20 itself 180
Since it is formed in a symmetrical shape, if one of the cutting edges 24 used as the outer peripheral edge wears out, rotate it 180 degrees and use the cutting edge 26 as the bottom edge, Since the cutting edge 25 facing to can also be used as the outer peripheral edge, it is excellent in economical efficiency.

[Other Embodiments] FIGS. 10 and 11 show another embodiment of the chip of the present invention.

This chip 35 is a plate-shaped plate having a substantially diamond shape with the upper and lower surfaces 36, 37 parallel to each other, and the lower surface 37 serves as a seating surface and cutting edges 38, 39, 40, 41 are formed on each ridge of the upper surface 36. Has been done.

Also in this chip 35, a pair of obtuse angle portions of the upper surface 36 are inclined surfaces in which the thickness between the upper and lower surfaces 36, 37 gradually decreases from the central portion side of the upper surface 36 toward the tip of the corner portion. Four
2 and 43, and stepped portions 44 and 45 extending from the inclined surfaces 42 and 43 in parallel with the lower surface 37 and reaching the tips of the corners. In addition, a mounting hole 46 for the chip 35, which penetrates the lower surface 37, is formed in the center of the upper surface 36.

Therefore, even with the chip 35 of this example, it is possible to obtain the same operational effect as the chip shown in the first example.

In addition, in the above embodiment, the step portions 29, 30, 44, and 45 that are continuous with the inclined surface are formed by the surface parallel to the lower surface, but the invention is not limited to this and is shown in FIGS. 12 and 13. It may be formed by a surface having a gentler inclination angle than the inclined surface 51, such as the step portion 50.

Further, in each of the above-described embodiments, an example in which the tip of the present invention is mounted on the end mill body 1 has been described, but the present invention is not limited to this. For example, the chip is mounted on various throw-away type drilling tools such as throw-away type drills. Even in the case, the same effect can be obtained.

[Advantages of the Invention] As described above, the present invention has a throw-away tip that has a polygonal plate shape and has a lower surface as a seating surface and a cutting edge formed on at least two ridge portions of the upper surface. In, the corner portion continuous with the cutting edge of the upper surface,
An inclined surface in which the thickness of the upper and lower surfaces gradually decreases from the central portion side of the upper surface toward the tip of the corner portion, and an inclined surface inclined from this inclined surface at a gentler inclination angle than this inclined surface or parallel to the lower surface. It is formed by a step portion extending to the tip of the corner portion, and the inclined surface and the step portion are continuously provided in a range from one of the two cutting edges sandwiching the corner portion to the other. Since it is characterized, the following effects are exhibited.

Even when the throw-away tip with the above configuration is attached to the tool body to give a positive axial rake angle,
It is possible to secure a large clearance angle of the throw-away tip at the tip of the inner peripheral blade. Therefore, it is possible to secure a large back metal amount below the seating surface of the tool body while securing the edge strength of the throw-away tip. it can.
Moreover, the cutting edge located on the outer peripheral side and the cutting edge located on the inner peripheral side of the tool body can be used interchangeably, which is excellent in economic efficiency.

[Brief description of drawings]

1 to 9 show a first embodiment of a throwaway chip (chip) of the present invention. FIG. 1 is a front view and FIG. 2 is a view taken along line A ₁ -A _{1 of} FIG. , Fig. 3 shows A ₂ -A _{2 in} Fig. 1.
Line plan view, Figure 4 is a bottom view, Fig. 5 A ₃ -A ₃ line view of Figure 1, Figure 6 is a side view showing a state of mounting the chip on the mill body, FIG. 7 is A ₄ -A ₄ line view of FIG. 6, 8
The figure is a schematic view showing the mounted state of the above-mentioned chip, and Fig. 9 is the eighth diagram.
Enlarged view of B part of the figure, FIGS. 10 and 11 is intended to show another embodiment of the present invention, Figure 10 is a front view, FIG. 11 A ₅ -A ₅ line view of Figure 10 FIGS. 12 and 13 show another embodiment of the present invention. FIG. 12 is a front view and FIG. 13 is a front view.
A ₆ -A ₆ line view of Figure 12, FIG. 14-FIG. 18 shows a mill body fitted with a conventional slow-Au H. class tap, FIG. 14 is a front view, 15
FIG. 16 is a side view, FIG. 16 is a view taken along the line A ₁₁ -A _{11 in} FIG. 15, FIG. 17 is a schematic view showing the mounted state of the above-mentioned chip, and FIG. 18 is an enlarged view of a C part in FIG. . 20,35 …… Chip (throw away chip), 21,36 …… Upper surface, 22,37 …… Lower surface, 23〜26,38〜41 …… Cutting edge, 27,28,42,43,51 …… Inclined Surface, 29,30,44,45,50 …… Step, α …… Axial rake angle, H, H ₁ …… Overhang amount.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hozo Funaki 1-27-20 Nishi-Shinagawa, Shinagawa-ku, Tokyo Mitsubishi Metals Co., Ltd. Tokyo Works (56) Bibliography Sho 55-55314 (JP, U) 52-118468 (JP, U)

Claims (1)

[Claims] 1. A throw-away tip having a polygonal plate shape, a lower surface serving as a seating surface, and cutting edges formed on at least two ridges of the upper surface, which are continuous with the cutting edges on the upper surface. The angled portion is inclined from the center side of the upper surface toward the tip end side of the angled portion and the thickness of the upper and lower surfaces is gradually reduced, and is inclined from the inclined surface at a gentler inclination angle than the inclined surface, or It is formed by a step portion that extends parallel to the lower surface and reaches the tip of the corner portion, and the inclined surface and the step portion are each continuous in a range from one of the two cutting edges sandwiching the corner portion to the other. A throw-away tip, which is characterized by being installed in.