JPH0214895Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a positive throw-away tip that is attached to the outer periphery of a cutting tool body such as a face miller or cutter with a positive axial rake angle. It is.

[Prior Art] In recent years, among the above-mentioned positive throw-away chips (hereinafter abbreviated as chips), in particular, the external appearance is a polygonal plate shape, and a main cutting edge is formed on at least one side of the upper surface. At the same time, various types of chips are being developed in which the rake face along the main cutting edge is formed into a convex curved shape.

FIGS. 12 to 15 show an example of a conventional chip of this type.

This chip 1 is formed into a plate shape with a substantially diamond-shaped appearance, and main cutting edges 4, 4 are formed on a pair of opposing sides 3, 3 of the sides 3 of the upper surface 2. At the same time, flank surfaces 6, 6 of the main cutting edges 4, 4 are formed on the side surface extending from the main cutting edges 4, 4 to the lower surface 5, which is the mounting surface. The rake surface 9 of the upper surface 2 extending from the cutting edge tip 7 to the cutting edge rear end 8 along the main cutting edge 4 is a cylindrical surface (convex) in which the main cutting edge 4 draws a substantially arc shape. curved surface)
It is formed by Here, the rake face 9
The cylindrical surface (convex curved surface) forming the upper and lower surfaces 2,
The maximum thickness portion 10 between the main cutting edges 4 and 5 is formed so as to be located in the center between the cutting edge tip 7 and the cutting edge rear end 8 of the main cutting edge 4.

By the way, in the chip 1 whose rake face 9 is formed by a cylindrical surface (convex curved surface) in this way,
It is known that it has a large blade angle at the tip of the cutting edge, which provides excellent blade strength, and has unique advantages such as reducing cutting resistance and cutting heat generation due to its unique cutting action. Further, as shown in FIG. 16, for example, the tip seat 13 of the cutter body 12 is attached at a positive inclination angle α with respect to the axis X of the cutter body 12 (if the rake face 9 is parallel to the lower surface 5, When the main cutting edge 4 is mounted at an angle corresponding to a positive axial rake angle, a positive tangential angle β larger than the mounting inclination angle α is obtained, particularly at the rear of the central portion of the main cutting edge 4. Therefore, this chip 1 has the advantage of being excellent in chip removal performance in the direction along the rake face 9.

[Problem that the invention attempts to solve] However, in such chip 1, the first
When the cutter body 12 is attached to a relatively large-diameter cutter body 12 as shown in Fig. 6 and used for machining a cutting surface with a wide cutting width, the chips are removed from the main cutting edge as shown in Fig. 17. 4 toward the center of rotation of the cutter body 12. On the other hand, in the conventional chip 1, as shown in FIG. Although a small wall portion 14 is formed to prevent the chips from extending, as shown in FIG. 15, no part is formed in the center of the main cutting edge 4 to control the chips from extending. Therefore, when the cutting width becomes large, the chips extending toward the cutter body 12 violently collide with the cutter body 12, which causes vibrations, and the chips are not cut, causing the main cutting edge 4 to collide with the cutter body 12. There were problems such as the main cutting edge 4 being damaged due to the large force acting on it. Furthermore, since the angle between the small wall portion 14 and the rake face 9 at the cutting edge tip 7 of the main cutting edge 4 is approximately a right angle, it is easy for chips to become clogged, which can lead to breakage and chatter of the main cutting edge 4. There were also problems that were said to be a contributing factor to the occurrence of.

[Purpose of the invention] This invention was made in view of the above circumstances.
In addition to the excellent cutting performance peculiar to the convexly curved rake face, it also has excellent chip removal performance in the direction that intersects the main cutting edge over its entire length, which prevents the occurrence of harmful vibrations and chatter during cutting. The object of the present invention is to provide a positive throw-away tip that can prevent this from occurring.

[Means for Solving the Problems] The positive throw-away tip of this invention has a polygonal strip shape, and has a main cutting edge formed on at least one side of the upper surface, and a main cutting edge on at least one side of the upper surface. The rake face along the main cutting edge of a positive throw-away chip is formed into a smooth convex curved surface along the main cutting edge, and the rake face along the main cutting edge is directed downward from the upper surface toward the main cutting edge. A corner portion along the main cutting edge and on the tip side of the main cutting edge, which has a concave curved surface for cutting and an inclined surface in which the thickness between the upper and lower surfaces gradually increases from the bottom of the concave curved surface toward the main cutting edge. It is formed with a convex curved surface including.

[Embodiment] Figures 1 to 3 show a first embodiment of the chip of this invention.

In FIGS. 1 to 3, this chip 20 is formed into a plate shape with a substantially diamond-shaped appearance, and a pair of opposing sides 23, 23 of the sides 23 of the upper surface 21 are mainly formed. Cutting edges 24, 24 are formed. The rake face 27 of the main cutting edge 24 extends from the cutting blade tip 25 to the cutting blade rear end 26, including the upper surface 21 and the corner X portions on the tip side and the rear end side of the main cutting edge 24 on the upper surface 21. are each formed by a cylindrical convex curved surface that curves in the direction along the main cutting edge 24. Here, the upper surface 21 and the rake surface 27 of the main cutting edge 24 refer to the maximum thickness part 29 between the upper and lower surfaces 21 and 28, and the cutting edge tip 25 and the cutting edge rear end of the main cutting edge 24. 26. Furthermore, the rake surface 27 is a concave curved surface that cuts in a direction perpendicular to the main cutting edge 24, that is, from the upper surface 21 toward the main cutting edge 24, from the upper surface 21 to the lower surface 28 at a constant depth h. 30 and this concave curved surface 30
It is formed of an inclined surface 32 in which the thickness between the upper and lower surfaces 21 and 28 gradually increases from the bottom 31 of the blade toward the main cutting edge 24 having the same thickness as the upper surface 21.

However, for such chip 20,
The rake surface 27 of the main cutting edge 24 is directed from the upper surface 21 toward the main cutting edge 24, and a concave curved surface 30 cuts from the upper surface 21 toward the lower surface 28, and this concave curved surface 3
An inclined surface 3 in which the thickness between the upper and lower surfaces 21 and 28 gradually increases from the bottom 31 of the 0 toward the main cutting edge 24.
2 and formed by a cylindrical convex curved surface along the main cutting edge 24, as shown in FIG. It can be cut into short pieces and discharged smoothly. As a result, in addition to the above-described effects unique to the chip 20 having the convexly curved rake face 27, the chip removal performance in the direction perpendicular to the main cutting edge 24 can be greatly improved. effect can be obtained.

In addition, since the rake face 27 along the main cutting edge 24 is formed with a convex curved surface including the corner portions on the leading and trailing edges of the main cutting edge, the tool angle at both ends of the main cutting edge 24 is large, and this portion Excellent strength, ie, cutting edge strength. Therefore, such chips 20 are used as the first
To prevent chipping of the cutting edge tip of the main cutting edge 24 even when large cutting resistance acts on the cutting edge tip of the main cutting edge 24 by mounting it on a cutter body 12 as shown in Fig. 6 with the axial rake angle being positive. The excellent effect of being able to do this can be obtained.

Furthermore, for example, when a chip with a straight main cutting edge is mounted on the cutter body 12 as shown in FIG. 16 with the axial rake angle positive, the radius of rotation at the center of the main cutting edge is The radius of rotation is smaller than the radius of rotation at the rear end, and as a result, the machined surface of the workpiece is cut into a convex curved surface that protrudes at the center, resulting in a disadvantage that the processing accuracy is poor.

However, the tip 20 with the above configuration has a positive rake face 27 along the main cutting edge 24.
is formed of a smooth convex curved surface along the main cutting edge, so the main cutting edge 24 becomes a smooth curve convex toward the outside of the chip 20 when viewed from the rake face 27 side of the chip 20. Therefore, when such a chip 20 is mounted on the cutter body 12 with the axial rake angle being positive as shown in FIG. By creating a curve that coincides with the same circular arc surface centered on the rotation axis of the cutter body 12, the machining surface of the workpiece can be formed at right angles to the machining bottom surface, which improves machining accuracy. It is possible to obtain the excellent effect of significantly improving the

In the chip 20 of the above embodiment, the depth from the top surface 21 to the bottom 31 of the concave curved surface 30,
Although the heights from the bottom 31 to the main cutting edge 24 are equal to each other, the height is not limited to this. As shown in FIG. The height H up to the main cutting edge 24 is formed to be small, or conversely, as shown in FIG. 6, the height H of the main cutting edge 24 is formed larger than the depth h of the concave curved surface 30. It may be something that has been done.

[Other Embodiments] FIGS. 7 to 9 show a second embodiment of the chip of this invention.

7 to 9, this chip 35 has an upper surface 36 formed by a plane parallel to the lower surface 37, and a pair of main cutting edges 38 formed on the sides of the upper surface 36. The rake face 39 is
A convex curved surface that has a cylindrical shape along the main cutting edge 38 and is widest at the center of the main cutting edge 38 and narrows at the front and rear ends of the main cutting edge 38. It is formed. The rake face 39 further includes a concave curved surface 40 that cuts at a constant depth h from the upper surface 36 toward the main cutting edge 38 in a direction perpendicular to the main cutting edge 38 . It is formed by an inclined surface 42 whose thickness gradually increases from the bottom portion 41 toward the main cutting edge 38 .

Further, FIGS. 10 and 11 show a third embodiment of the chip of this invention, and show an example in which the chip is applied to a chip having a substantially rectangular external appearance.

In this chip 45, main cutting edges 47 are formed on each side 46 of the upper surface 41, and auxiliary cutting edges 48 are further formed at each corner between the main cutting edges 47, that is, at each corner. Moreover, in this chip 45,
The rake face 49 of the main cutting edge 47 includes one of the minor cutting edges 48 formed at the corner portion, and the rake face 49
It is formed by a convex curved surface with the maximum thickness portion 50 of No. 9 located at the tip of the cutting edge of the main cutting edge 47. The rake face 49 is formed of a concave curved surface 51 and an inclined surface 52, which are similar to those in the embodiment described above, in a direction perpendicular to the main cutting edge 47. Here, the depth h of the concave curved surface 51 from the upper surface 41
is formed to be constant along the main cutting edge 47.

Therefore, even with the chips 35 and 45 shown in the second and third embodiments, it is possible to obtain excellent chip removal performance similar to that shown in the first embodiment, and also to have an excellent cutting edge. Strength is obtained,
Furthermore, processing accuracy can be significantly improved.

[Effects of the invention] As explained above, the positive throw-away tip of this invention has a polygonal plate shape, and has a main cutting edge formed on at least one side of the upper surface, and a main cutting edge on at least one side of the upper surface. The rake face along the main cutting edge of a positive throw-away chip is formed into a smooth convex curved surface along the main cutting edge, and the rake face along the main cutting edge is directed downward from the upper surface toward the main cutting edge. Along the main cutting edge having a concave curved surface for cutting and an inclined surface in which the thickness between the upper and lower surfaces gradually increases from the bottom of the concave curved surface toward the main cutting edge,
It is formed with a convex curved surface including a corner portion on the tip side of the main cutting edge. Therefore, with this chip, in addition to the excellent effects peculiar to a chip having a convexly curved rake face, it is possible to obtain excellent chip removal performance over the entire length of the main cutting edge.

In addition, excellent cutting edge strength can be obtained, and machining accuracy can be significantly improved.

[Brief explanation of the drawing]

Figures 1 to 3 show the first embodiment of the positive throw-away chip of this invention.
2 is a front view, FIG. 2 is a side view taken from the - line in FIG. 1, FIG. 3 is a side view taken from the - line in FIG. The enlarged view, FIG. 5, and FIG. 6 are side views and FIGS. 7 to 9 showing modified examples of the first embodiment, respectively.
The figures show a second embodiment of this invention, in which Fig. 7 is a front view, Fig. 8 is a side view taken from - line in Fig. 7,
Fig. 9 is a side view taken from the - line in Fig. 7, Figs. 10 and 11 show a third embodiment of this invention, Fig. 10 is a front view, and Fig. 11 is a side view taken from the line XI of Fig. 10.
- It is a side view seen on the XI line. 12 to 15 show a conventional chip, in which FIG. 12 is a front view, FIG. 13 is a side view taken along the - line in FIG.
Figure 4 is a sectional view taken along the - line in Figure 12, and Figure 15.
12 is a sectional view taken along the line 12, FIG. 16 is a view showing the conventional tip mounted on the cutter body, and FIG. 17 is a partially enlarged view showing the state of cutting with the conventional tip. 1, 20, 35, 45...Positive throw-away tip, 2, 21, 36, 41...Top surface,
3, 23, 46... Side part, 4, 24, 38, 47
...Main cutting edge, 5,28,37...Bottom surface, 9,2
7, 39, 49... rake surface, 12... cutter body, 30, 40, 51... concave curved surface, 31, 41...
...bottom, 32, 42, 52...slanted surface, 48...
Minor cutting edge.

Claims (1)

[Claims for Utility Model Registration] It has a polygonal plate shape, and has a main cutting edge formed on at least one side of the upper surface, and a rake face along the main cutting edge of the upper surface is formed on the main cutting edge. In a positive throw-away tip formed of a smooth convex curved surface along the contour, the rake face is formed by a concave curved surface that cuts downward from the upper surface toward the main cutting edge, and a concave curved surface that cuts downward from the bottom of the concave curved surface toward the main cutting edge. 1. A positive throw-away tip, characterized in that it is formed with a convex curved surface that extends along the main cutting edge and includes a corner portion on the tip side of the main cutting edge, and has an inclined surface in which the thickness between the upper and lower surfaces gradually increases.