JPH0134729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a throw-away tip used as a cutting tool such as a face miller or a cutter.

[Prior art and its problems]

In recent years, among the above-mentioned throw-away chips, various positive throw-away chips are being developed, in particular, in which the rake face along the main cutting edge is formed into a convex curved shape.

10 to 12 show an example of a conventional throw-away tip of this type, and each corner of the upper surface 2 of the throw-away tip 1, which has a substantially rectangular plate shape as a whole, has auxiliary cutting edges 3... are formed, and main cutting edges 4 are formed on the sides between these minor cutting edges 3. Further, on the side surface of the throw-away chip 1, there is a main cutting edge flank 6 and a sub-cutting edge flank 6 that are inclined toward the center of the throw-away chip 1 from the main cutting edge 4 and the auxiliary cutting edge 3 and reach the lower surface 5, respectively. A cutting edge flank surface 7 is formed. A pair of corresponding main cutting edges 4, 4 among the main cutting edges 4... are arranged so that the cutting edge ridgeline forms a substantially arc-shaped convex curve.
The rake faces 8, 8 are formed by cylindrical convex curved surfaces. Here, the rake face 8 is formed so that its top 9 contacts the upper surface 2 at a position offset by a length A toward the cutting blade tip 10 from an intermediate position 12 between the cutting blade tip 10 and the cutting blade rear end 11. has been done. Note that the reference numeral 13 in the figure is a rising portion continuous from the rake face 8 to the upper surface 2.

However, in the case of the throw-away tip 1 in which the rake face 8 is formed by a convex curved surface, the cutting edge has a large tool angle at the tip, and has excellent cutting edge strength, and its unique cutting action reduces cutting resistance. It is known that it has advantages such as reducing generation of cutting heat.

However, in the conventional throw-away tip 1, the convex curved rake face 8 is
However, since the main cutting edge 4 is formed in a position that is biased towards the cutting edge tip 10 side from the intermediate position 12 between the cutting edge rear ends 10 and 11, the position of the cutting edge rear end 11 with respect to the upper surface 2 is The position will be lower than the tip 10 of the cutting blade. Therefore, in the side portion of the main cutting edge 4 adjacent to the rear end 11 of the cutting edge, the portion where the cutting edge tip 10 similar to the main cutting edge 4 should be formed has already been formed when forming the convex curved surface 8. Since it has been scraped off, it is not possible to form a convex curved surface 8 similar to the main cutting edge 4 on the side, and therefore, the main cutting edges 4, 4 are formed on the two opposing sides. However, all the sides cannot be used as the main cutting edge 4 having the convex curved surface 8, which has the disadvantage of being inferior in economic efficiency.

Therefore, as shown in FIG.
A rising wall 16 is formed from 4 toward the upper surface 15,
A throw-away tip has also been proposed that secures a machining allowance for the cutting edge tip 18 to form the adjacent main cutting edge 17 into a convex curved shape.

However, this throw-away tip has the drawback that a deep pocket 20 is formed between the rake face 19 on the rear end side of the main cutting edge 17 and the above-mentioned rising wall 16, making it extremely difficult to remove chips. .

For this reason, a throw-away chip 21 as shown in FIGS. 14 to 16 has been proposed to improve the above-mentioned drawbacks.

This throw-away tip 21 has a main cutting edge 22.
The rake face 23 is the top part 24 of the cutting edge tip 25.
It is formed into a cylindrical convex curved surface that contacts the upper surface 28 at a position offset by a length A toward the cutting blade rear end 26 from the center position 27 between the cutting blade rear end 26 and the cutting blade rear end 26. That is, in this throw-away tip 21, the position of the cutting blade rear end 26 with respect to the upper surface 28 is higher than the position of the cutting blade tip 25.
Thereby, at the rear end of the main cutting edge 22, it is possible to secure a cutting allowance for similarly forming the rake face 23 of the adjacent main cutting edge 22 into a convex curved surface. Therefore, this throw-away tip 2
In the case of No. 1, the rake faces 23 of the main cutting edges 22 on all sides thereof can be formed into convex curved surfaces.

However, in the conventional throw-away tip 20, the rake face 23, which is a cylindrical convex curved surface, is arranged such that the top part 24 thereof is deviated from the center position 27 toward the rear end 26 of the cutting blade. As a result, the angle α between the cutting edge tip 25 and the upper surface 28 becomes extremely large.
Therefore, as shown in FIGS. 17 and 18, when attaching this throw-away tip 21 to the cutter body 29, the cutter body 2
In order to prevent the angle β between the plane O parallel to the axis of the cutter 9 and the tangent at the cutting edge 25 from becoming at least negative, the angle of inclination I should be greater than that shown in FIGS. 10 to 13 above. must be made large. Therefore, as shown in FIGS. 17 and 18, in order to obtain a predetermined relief angle θ,
It is necessary to form a large relief angle in the throw-away tip 21 itself in advance, so that
Inevitably, the area of the lower surface of the throw-away tip 21 decreases, resulting in a decrease in seating rigidity and machining accuracy, as well as a problem in that the thickness near the cutting edge 25 becomes thinner, decreasing the strength of the cutting edge.

[Purpose of the invention]

This invention was made in view of the above circumstances,
To provide a throw-away tip which is highly economical by forming the rake faces of all main cutting edges formed on each side into a convex curved surface, has excellent cutting performance, and has good chip disposal. The purpose is to

[Structure of the invention]

The throw-away tip of the present invention has a polygonal shape with upper and lower surfaces parallel to each other, and a minor cutting edge is formed at each corner of the upper surface, and one end of the tip is formed on a side located between these minor cutting edges. The upper surface of the throw-away chip along the main cutting edge formed with the main cutting edge connected to the auxiliary cutting edge extends from one end of the main cutting edge to the other end, and the apex extends between both ends of the main cutting edge. A convex curved surface located at a position offset from the center to one end side, and this convex curved surface touches the other end side of the main cutting edge and extends from the above upper surface near the minor cutting edge located on the other end side of the main cutting edge. It is formed from an extending concave curved surface.

〔Example〕

1 to 3 show an example of the throw-away tip of the present invention.

This throw-away tip 30 has a substantially rectangular plate shape, and has auxiliary cutting edges 32 at each corner of the upper surface 31.
However, main cutting edges 33 are formed on the sides between these minor cutting edges 32, respectively. Here, the upper surface 34 of the side portion along each main cutting edge 33 of this throw-away tip 30 extends from the cutting edge tip 35 of the main cutting edge 33 to the cutting edge rear end 36, and the main cutting edge 33 Cylindrical convex curved surface 3 forming the rake surface of
7, and a concave curved surface 38 extending from the position of the cutting edge rear end 36 of this convex curved surface 37 to the vicinity of the auxiliary cutting edge 32 on this cutting blade rear end 36 side.

The convex curved surface 37 has a top portion 40 at the cutting edge tip 3.
It is formed so as to contact the upper surface 31 at a position offset by a length A toward the cutting blade tip 35 from a central position 41 between the cutting blade 5 and the rear end 36 of the cutting blade. Further, the concave curved surface 38 has a rear end 36 of the cutting blade on the convex curved surface 37.
A cross section is formed in an arcuate concave curved surface with a radius R so as to touch at a position and extend from there to a position at the same height as the upper surface 31 in the vicinity of the auxiliary cutting edge 32. Note that the reference numeral 42 in the figure indicates the convex curved surface 37 and the concave curved surface 3.
This is a rising surface that smoothly extends from the upper surface 34 consisting of 8 to the upper surface 31.

However, such a throwaway tip 3
0, the upper surface 34 along the main cutting edge 33 is formed from a convex curved surface 37 and a concave curved surface 38, and the convex curved surface 37 is formed so that its top 40 meets the cutting edge tip 35 and the cutting edge rear end 36. Since it is formed so that the position is biased toward the cutting blade tip 35 side from the center position 41 between them, the angle α between the cutting blade tip 35 and the upper surface 31 is as shown in FIGS. 14 to 16. Unlike conventional ones, it does not become unnecessarily large. Therefore, as shown in FIGS. 19 and 20,
Place the throw-away tip 30 above on the cutter body 2.
9, in order to prevent the angle β 1 between the plane O parallel to the axis of the cutter body 29 and the tangent at the cutting edge 35 from becoming negative, the angle _β1 shown in FIGS. There is no need to make the inclination angle I ₁ large as in the case shown in .
Therefore, as shown in FIGS. 19 and 20, in order to obtain a predetermined clearance angle θ, it is not necessary to form a large clearance angle in advance in the throwaway chip 30 itself, and thus the There is no risk that seating rigidity or processing accuracy will decrease due to a reduction in area. Therefore, it is possible to obtain excellent cutting performance such as excellent cutting edge strength and low cutting resistance and generation of cutting heat.

Moreover, from the cutting edge rear end 36 of the convex curved surface 37,
The concave curved surface 38 extends up to the same height as the upper surface 31 near the auxiliary cutting edge 32 adjacent to the rear end 36 side of the cutting edge.
Since the main cutting edge 33 is raised smoothly, sufficient machining allowance can be secured for forming similar convex curved surfaces 37 and concave curved surfaces 38 along the adjacent main cutting edges 33. As a result, the upper surface 34 along all the main cutting edges 33 formed on each side can be formed from a convex curved surface 37 and a concave curved surface 38,
Therefore, it can be made highly economical. Further, the concave curved surface 38 allows chips to be smoothly removed from the concave curved surface 38 via the rising surface 42.

[Other Examples]

FIGS. 4 and 5 show a second example of the throw-away chip of the present invention, which is applied to an equilateral triangular throw-away chip.

In the throw-away tip 50 of this example, auxiliary cutting edges 56 are provided at each of the three corners of the upper surface 51.
... are formed, and main cutting edges 52 are formed at the sides between these sub-cutting edges 56, 56, which are continuous from the linear portions of these sub-cutting edges 56 via circular arc portions.
Thus, the throw-away tip 50 has an upper surface 53 along the main cutting edges 52, each having a convex curved surface similar to that shown in FIGS. 1 to 3.
4 and a concave curved surface 55.

Here, FIG. 21 shows a state in which the throw-away tip 50 of this example is attached to the cutter body 57.

Moreover, FIG. 6 and FIG. 7 show the third embodiment of this invention.
The throw-away chip 60 of this example has the arc radius r of the concave curved surface 61 set to the first
It is made as small as possible than the one shown in the figures through FIG. 3, and the length of the convex curved surface 62 along the main cutting edge 63 is made relatively longer.

Furthermore, FIGS. 8 and 9 show a fourth example of the present invention, and the throw-away tip 65 of this example has the terminal end 67 of the concave curved surface 66 within a range that does not interfere with the adjacent auxiliary cutting edge 68. It is formed as close to the auxiliary cutting edge 68 side as possible. Further, FIGS. 22 to 25 show a fifth example of the present invention, which is applied to a device having a substantially parallelogram external appearance. The throw-away tip 70 in this example has auxiliary cutting edges 71 at each of the four corners.
... are formed, and main cutting edges 72 are formed on the sides between these minor cutting edges 71.
The upper surface 73 along each main cutting edge 72 is formed by a convex curved surface 74 and a concave curved surface 75 similar to the above. However, this throwaway tip 70
are attached to a cutter body 76 or a cutter body 77, respectively, in the state shown in FIG. 26 or 27. These throw-away chips 50, 60, 65, and 70 shown in the second to fifth examples can also provide the same effects as those shown in the first example, and also have the same effects as those shown in the first example. The throw-away tips 60, 65 shown in the third and fourth examples have the advantage that the depth of cut can be increased during cutting.

〔Effect of the invention〕

As explained above, the throw-away tip of the present invention has a polygonal shape with parallel upper and lower surfaces, a minor cutting edge is formed at each corner of the upper surface, and a side portion located between these minor cutting edges. The upper surface of the throw-away chip, which is formed with a main cutting edge that is connected to the minor cutting edge at one end, extends from one end of the main cutting edge to the other end, and the top surface is connected to the main cutting edge. a convex curved surface located at a position offset to one end side from the center between both ends of the convex curved surface, and a auxiliary cutting edge that contacts the other end side of the main cutting edge of this convex curved surface and is located on the other end side of the main cutting edge. It is formed from a concave curved surface extending to the upper surface nearby. Therefore, according to this throw-away chip, the rake faces of all the main cutting edges formed on each side can be formed into convex curved surfaces, so that all the main cutting edges have the excellent It is economical and provides good cutting performance. Moreover, since chips are smoothly removed along the concave curved surface, advantages such as excellent chip disposal can be obtained.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the throw-away tip of the present invention, in which FIG. 1 is a side view, FIG. 2 is a plan view, and FIG.
A line sectional view, FIGS. 4 and 5 show a second embodiment of the invention, FIG. 4 is a plan view, FIG. 5 is a side view, and FIGS. 6 shows a plan view, FIG. 7 shows a side view, and FIGS. 8 and 9 show a fourth embodiment of the invention, with FIG. 8 being a plan view. Figure, No. 9
The figure is a side view, Figures 10 to 12 show conventional throw-away tips, Figure 10 is a side view, Figure 11 is a plan view, and Figure 12 is the same as Figure 11.
A sectional view taken along line XII-XII, FIG. 13 is a side view showing another conventional throw-away chip, FIGS. 14 to 16 are views showing other conventional throw-away chips, and FIG. 14 is a side view. , Figure 15 is a plan view,
Fig. 16 is a sectional view taken along the - line in Fig. 15, Fig. 17 is a view showing a conventional throw-away tip attached to the cutter body, and Fig. 18 is a sectional view taken along the - line in Fig. 17. The figure shows the state in which the throw-away tip of the first example of this invention is attached to the cutter body, and Fig.
21 is a view showing the throw-away tip of the second example of the present invention attached to the cutter body, and FIGS. 22 to 25 are
The figure shows a fifth embodiment of the invention.
Figure 2 is a plan view, Figure 23 is the - of Figure 22.
Linear view, Fig. 24 is - of Fig. 22
Linear view, Fig. 25 is - of Fig. 22
The line sectional view, FIG. 26, and FIG. 27 are views showing the state in which the throw-away tip of the fifth embodiment is attached to the cutter body, respectively. 1, 21, 30, 50, 60, 65, 70...
Throwaway tip, 31, 34, 51, 5
3, 73...Top surface, 32, 56, 68, 71...
Minor cutting edge, 33, 52, 63, 72...Main cutting edge, 4
0... Top, 35... Cutting blade tip, 36... Cutting blade rear end, 41... Intermediate position, 42... Rising surface, 3
7, 54, 62, 74...Convex curved surface, 38, 55,
61, 66, 75...Concave curved surface.

Claims (1)

[Claims] 1. A polygon whose upper and lower surfaces are parallel, and a minor cutting edge is formed at each corner of the upper surface, and one end of the side portion located between these minor cutting edges is formed with the minor cutting edge. In a throw-away chip formed with a main cutting edge connected to the cutting edge, the upper surface along the main cutting edge extends from one end of the main cutting edge to the other end, and the apex is between both ends of the main cutting edge. A convex curved surface located at a position offset from the center to one end side, and this convex curved surface contacts the other end side of the main cutting edge and extends from the above upper surface near the minor cutting edge located on the other end side of the main cutting edge. A throw-away tip characterized by being formed from an extending concave curved surface. 2 It has a polygonal shape with upper and lower surfaces parallel to each other, and a minor cutting edge is formed at each corner of the upper surface, and a main cutting edge that is connected to the minor cutting edge at one end is formed on the side between these minor cutting edges. In the indexable tip formed with a blade, the upper surface along the main cutting edge extends continuously from the auxiliary cutting edge to the other end of the main cutting edge via one end of the main cutting edge, and the apex is A convex curved surface located at a position offset to one end side from the center between both ends of the main cutting edge, and a sub-curved surface located in contact with the other end side of the main cutting edge of this convex curved surface and located on the other end side of the main cutting edge. A throw-away tip characterized in that it is formed of a concave curved surface extending to the above-mentioned upper surface near the cutting edge.