JPH0737774Y2 - Throw-away tip - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a throw-away tip that is detachably mounted as a cutting blade on the outer periphery of the tip of an end mill or the like.

[Prior Art] FIGS. 9 to 11 show a conventional throw-away chip of this type (hereinafter, simply referred to as a chip) found in Japanese Utility Model Laid-Open No. 61-134812.

This chip 1 has a plate-like shape and is formed on the upper edges of both side surfaces 2 and 2.
The cutting edges 3 and 3 having a substantially arc shape of 1/4 or less and linear ridge lines 4 and 4 continuous with the cutting edges are formed, and the cutting edge 3 has a circular shape
The convex cutting edge 6 is formed from the side surface 2 to the rake face 5 along the cutting edge 3 at a portion where the end of the edge intersects with the end of the adjacent linear ridge line 4.

As shown in FIG. 11, the above-mentioned conventional tip 1 is used by being detachably fixed to the tip portion of the end mill body 7 so that the convex cutting edge 6 and the arcuate cutting edge 3 participate in the cutting. It

According to the above-mentioned conventional tip 1, the convex cutting edge 6 is first cut during cutting.
Bites on a work material (not shown), and then the entire arcuate cutting edge 3 gradually cuts as the end mill body 7 rotates, so that no shocking cutting load is applied. Such an advantage can be obtained.

[Problems to be Solved by the Invention] However, in the above-described conventional tip 1, the cutting edge tip angle θ at the intersection of the arcuate cutting edge 3 and the end of the linear ridge line 4 adjacent thereto. Is an acute angle (the size changes along the arc-shaped ridge of the cutting edge 3), there is a problem that the cutting edge is likely to be damaged. Furthermore, the convex cutting edge 3
There was also a problem that the standing wall 9 formed between the upper surface 8 and the upper surface 8 hinders the discharge of chips.

The present invention aims to solve the above problems.

[Means for Solving the Problems] The throw-away tip of the present invention has a plate shape with a substantially elliptical appearance, and follows a substantially elliptical arc at the ridge line portion between the upper surface and the side surface which are rake faces. The cutting edge and the end of this cutting edge and the linear small cutting edge that intersects at an obtuse angle in a plan view are alternately formed, and the tip part along the small cutting edge and the ends of the two cutting edges. The entire rake face is a convex curved surface that gradually approaches the lower surface side from the center side of the upper surface toward the small cutting edge, and this convex curved surface is from the end of one cutting edge to the other cutting edge of the other cutting edge. It is characterized in that it is formed so as to gradually approach the lower surface side toward the end portion of.

[Operation] In the chip having the above configuration, the tip of the cutting edge along the arc of the ellipse has a convex curved shape due to the rake face having the convex curved surface, and therefore an impact cutting load acts when biting. There is nothing to do. Further, the cutting edge and the small cutting edge intersect with each other at an obtuse angle in a plan view, and since the blade angle at the cutting edge end is large, the cutting edge strength at that portion is high and the cutting edge is prevented from being damaged. Further, unlike the conventional one, since there is no standing wall near the cutting blade which hinders the discharge of chips, the chips can be discharged smoothly.

[Embodiment] FIGS. 1 to 5 show an example of a chip of the present invention.

In FIGS. 1 to 5, the tip 10 is a substantially elliptical plate-like member having an upper surface 11 serving as a rake surface and a flat lower surface 12 serving as a seating surface. It is molded.

Between the upper and lower surfaces 11 and 12, there are two planar side surfaces 13 each having a short length intersecting the upper surface 11 at an acute angle, and two arcuate side surfaces 14 longer than the planar side surfaces 13. They are formed so as to alternate in the circumferential direction with an obtuse angle in between and to be point-symmetric with respect to the center of the chip 10.

Further, arcuate cutting edges 15a, 15b are formed on the ridge portion between each arcuate side surface 14 and the upper surface 11. In addition, as shown in FIG. 1, the ridge line portion between the planar side surface 13 and the upper surface 11 forms an obtuse angle δ in plan view with the end of each arcuate cutting edge 15a (or 15b). The linear small cutting edges 16 and 16 intersecting each other are formed. This obtuse angle δ forms the tip angle of each of the cutting edges 15a and 15b.

Furthermore, the entire upper surface 11 along the ends of the small cutting blade 16 and the cutting blades 15a, 15b is formed by a convex curved surface 17.
This convex curved surface 17 gradually approaches the lower surface 12 side from the central portion side of the upper surface 11 toward the small cutting edge 16 side, and is point-symmetrical with respect to each other with respect to the center, from each one cutting edge 15a, 15b side. It has a convex curved surface that gradually approaches the lower surface side toward the other cutting edge 15a, 15b side.

Specifically, the convex curved surface 17 is the small cutting edge.
The extension line of 16 is formed by a cylindrical circle of radius R parallel to the upper surface 11 and rotated by an angle α to the cutting edge 15a (or 15b) side, and further rotated to the lower surface 12 side by β °. It is a thing. As a result, each end of the cutting edges 15a, 15b is formed in a shape of a convex arc having a radius R when viewed in the direction of the reference line 1 as shown in FIG. Reference numeral 18 in the figure denotes a mounting hole for the chip 10.

As shown in, for example, FIGS. 6 to 8, the tip 10 having the above-described structure is detachably attached to the tip of an end mill body 20 having a substantially hemispherical tip through a mounting bolt 21, and the cutting is performed. Used as a blade. In this case, the tip 10
Is attached so that the tip of one of the cutting blades 15a is located in the vicinity of the axis O of the end mill body 20, and the small cutting blade 16 traverses the axis O and recedes toward the base end side of the end mill body 20. .

When cutting is performed with a ball end mill equipped with the above tip 10, the tip of the arcuate cutting edge 15a located on the axis O side of the tip 10 has a convex curved shape due to the convex curved surface 17, and therefore has an impact when biting. Therefore, it is possible to prevent the chipping thereof without applying any cutting load.

Moreover, in the tip 10, the tip angle of the cutting edge 15a that intersects the small cutting edge 16 is obtuse in plan view, and the convex curved surface 17 further causes the blade angle of the tip of the cutting edge 15a as shown in FIG. Since γ is about 90 ° or an obtuse angle, it is possible to significantly improve the cutting edge strength of the portion of the cutting edge 15a where a particularly large cutting load acts in the vicinity of the axis O, and the chips curl. Cheap.

In addition, like the conventional one, the flat side surface 13 on the small cutting blade 16 side
Since an upright wall that hinders the discharge of chips is not formed on the sheet, excellent chip discharge performance can also be obtained.

[Effects of the Invention] The throw-away tip according to the present invention intersects a cutting edge along an arc of an ellipse and an obtuse angle in plan view with the ridge line portion between the upper surface and the side surface which are rake surfaces. Linear cutting blades are formed alternately, and the entire rake face of the tip along the cutting blade and the ends of the two cutting blades gradually increases from the center side of the upper surface toward the cutting blade. It is a convex curved surface that approaches the lower surface side, and this convex curved surface is formed so as to gradually approach the lower surface side from the end of one cutting edge toward the end of the other cutting edge. Therefore, the cutting edge strength at the tip of the throw-away tip is high, the cutting edge strength at the small cutting edge can be increased, the impact cutting load does not act when biting, and the chipping of the tip can be further suppressed. Since there is no standing wall, there is an advantage that it is excellent in discharging chips. Moreover, due to the shape of such a convex curved surface, chips produced by cutting at the tip of the cutting blade are guided in the traveling direction so as to be easily curled, and the chip discharging performance is further improved.

[Brief description of drawings]

1 to 5 show a first embodiment of the chip of the present invention, FIG. 1 is a front view, FIG. 2 is a view taken along line II-II of FIG. 1, and FIG. 3 is a side view. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1, FIG. 5 is a perspective view of the tip in FIG. 2 as viewed from the reference line 1 direction, and FIGS. 6 to 8 show the tip in a ball end mill. Fig. 6 shows an example of mounting, front view,
Figure is a side view, Figure 8 is a bottom view, Figures 9-11 show a conventional tip, Figure 9 is a front view, Figure 10 is a side view, and Figure 11 is mounted on a ball end mill. It is a front view showing an example. 10 …… Chip (throw away tip), 11 …… Upper surface (rake surface), 12 …… Lower surface (seating surface), 13,14 …… Side surface, 15a, 15b …… Arc-shaped cutting edge, 16 …… Small Cutting edge, 17 ……
Convex curved surface, l ... Reference line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Okawa 1-27-20 Nishi-Shinagawa, Shinagawa-ku, Tokyo Mitsubishi Metals Co., Ltd. Tokyo Works (56) Reference JP-A-54-93284 (JP, A) Kai 55-37208 (JP, A) Actual 62-22014 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A cutting edge having a substantially elliptical plate shape, and a cutting edge along an arc of a substantially ellipse at a ridge line portion between an upper surface and a side surface which are rake surfaces, and an end portion of this cutting edge and a plan view. With linear small cutting blades intersecting obtusely with are formed alternately, the entire rake face of the tip portion along the small cutting blade and the ends of the two cutting blades, from the center side of the upper surface It is a convex curved surface that gradually approaches the lower surface side toward the small cutting edge side, and, moreover, this convex curved surface is from the end portion of one of the cutting blades toward the end portion of the other cutting blade, gradually toward the lower surface side. A throw-away tip that is formed so as to approach.