JPS6137458Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a throw-away tip suitable for use in ball end mills and the like.

As this type of throw-away chip, the present applicant previously proposed the ones shown in FIGS. 1 to 3. (Refer to Japanese Patent Application No. 57-18529.) The throwaway chip 1 according to the above proposal has a flat plate shape as a whole, and has a flat side surface 13 between the upper surface 11 and the lower surface 12. A substantially quarter circular arc surface 14 formed along the circumferential direction from there in contact with
A notch 15 having a substantially V-shaped cross section and extending from the upper surface 11 toward the lower surface 12 between the side surface 13 of one set and the circular arc surface 14 of the other set. is formed and defines the notch 15.
Of the two wall surfaces, the wall surface on the side 13 side is the flat surface 16
At the same time, the wall surface on the arcuate surface 14 side and the upper surface 1
1 is cut off, and a convex curved surface 17 is formed in which one end touches the upper surface 11 and the other end intersects the lower surface 12, and this convex curved surface 17, the upper surface 11, the arcuate surface 14, and the side surface A cutting edge 18 is formed on the edge formed by the cutting edge 13.

And this throwaway chip 1 is the fourth
As shown in Figures 7 to 7, the end mill body A
The chip seat B is placed on the chip seat B, and the side surface 13 and the flat surface 16 of the notch 15 are brought into contact with the side wall of the chip seat B, respectively, and the chip seat B is tightened and fixed with a tightening bolt C. In addition, in this fixed state, the convex curved surface 17, the circular arc surface 14, and the lower surface 1
2, that is, the inner edge P of the cutting blade 18 lies on the axis O of the end mill body A.

When cutting is performed using the throw-away ball end mill configured as described above, the cutting location of the cutting blade 18 gradually shifts from the inner edge P to the outer circumferential side as the end mill rotates. Therefore, no impact load is generated during cutting. Therefore, the cutting process is performed smoothly, and as a result, it is possible to improve the cutting speed and the precision of the surface to be cut. Furthermore, since the throw-away tip 1 has two cutting edges 18, if one cutting edge 18 becomes worn out, the other cutting edge 18 can be used, and the tip cost is therefore low. Become.

However, the above throwaway tip 1
In the above, there was a problem that the state of fixation to the chip seat B was unstable. In other words, in order to stably fix the throwaway tip 1,
It is desirable that the entire portion of the side facing surface other than the portion constituting the cutting blade 18, which is the cutting blade of the end mill, be brought into surface contact with the side wall of the chip seat B. However, most of the side facing surface of the throwaway tip 1 is occupied by the arcuate surface 14. It is very difficult to bring the side wall of the chip seat into surface contact with such an arcuate surface 14, and each time the chip is replaced, they may come into contact or come out of contact, and conversely, This may deteriorate the mounting accuracy of chip 1. Therefore, in the throw-away tip 1, the side surface 13 and the notch 1
Only two places, the flat surface 16 of the chip seat B, could be brought into surface contact with the side wall of the chip seat B, making the state of fixation to the chip seat B unstable.

In addition, since the inner edge P located at the center where a large thrust load acts is a so-called cusp, there is a problem that the strength of the area near it is low and the area near the inner edge P is easily damaged. Ta.

This invention was made in order to solve the above problems, and provides a throw-away tip that can improve the stability of attachment to the tip seat and also improve the strength of the inner edge of the cutting edge. The purpose is to

The feature of this invention is that while the convex curved surface of the throw-away tip mentioned above is formed over the entire wall surface on the arcuate side of the notch, the convex curved surface is formed from the upper end of the wall surface on the arcuate side to the upper surface. On the other hand, the lower end of the wall surface is a flat surface that touches the convex curved surface.

An embodiment of this invention will be described below with reference to FIGS. 8 to 14. Note that the same parts as in the conventional example described above are given the same reference numerals, and the explanation thereof will be omitted.

As shown in FIGS. 8 to 10, in the throw-away chip 2 according to this invention, the arcuate surface 14 of the two wall surfaces defining the notch 15 is
The intersection between the upper end of the side wall surface and the upper surface 11 is cut off to form a convex curved surface 27 whose upper end touches the upper surface 11. On the other hand, the arc surface 14
The lower end of the side wall surface is a flat surface 29 that contacts the convex curved surface 27 and extends from there toward the lower surface 12. This flat surface 29 is perpendicular to the lower surface 12 so that the side wall of the chip seat on which the chip 2 is placed and fixed can be easily formed, and the contact area with the side wall of the chip seat is In order to ensure this, it is desirable that the length be approximately 0.5 mm to 3 mm from the lower surface 12.

The throw-away tip 2 constructed as described above is placed on the tip seat B of the end mill main body A and fixed with a tightening bolt C, as shown in FIGS. 11 to 14. In this fixed state, the contact point between the cutting blade 18 and the flat surface 29, that is, the inner edge P of the cutting blade 18 is located on the axis O of the end mill body A.

Here, in this throw-away chip 2, since the lower end of the wall surface of the notch 15 on the side of the arcuate surface 14 is a flat surface 29, the chip also has the flat surface 29 in addition to the side surface 13 and the flat surface 16. It can be brought into surface contact with the side wall of the chip seat B, and the number of surface contact points with the side wall of the chip seat B is three. Therefore, the mounting stability of the chip 2 can be greatly improved.

In addition, since the flat surface 29 is formed in contact with the convex curved surface 27, the inner edge P is no longer a so-called cusp, but instead forms a point on a continuous ridge line formed by the convex curved surface 27, the flat surface 29, and the circular arc surface 14. As a result, the strength is improved, and damage to the neighboring portions can therefore be prevented.

In addition, although the case where the throw-away tip 2 is attached to the end mill main body has been described above, it may also be used for a side milling cutter, as shown in FIG. 15, for example.

As explained above, according to the throw-away chip of this invention, a convex curved surface is formed from the upper end of the wall surface on the arcuate side to the upper surface, while the lower end of the wall surface is a flat surface in contact with the convex curved surface. Therefore, the stability of attachment to the chip seat can be greatly improved, and the strength near the inner edge of the cutting blade can be improved to prevent chipping.

[Brief explanation of the drawing]

Figures 1 to 3 show an example of a conventional throw-away chip. Figure 1 is a plan view, Figure 2 is a side view, Figure 3 is a front view, and Figures 4 to 7 are examples of conventional throw-away chips. Fig. 4 is a plan view, Fig. 5 is a partially cutaway front view with some parts omitted, Fig. 6 is a view taken in the direction of the arrow in Fig. 4, and Fig. 7 shows an end mill using an away tip. Sectional view taken along the - line in Fig. 4, No. 8
Figures 1 to 10 show an embodiment of this invention,
Fig. 8 is a plan view, Fig. 9 is a side view, Fig. 10 is a front view, Figs. 11 to 14 show a ball end mill using a throw-away tip according to this invention, and Fig. 11 is a plan view. , FIG. 12 is a partially cutaway front view with some parts omitted, and FIG. 13 is a partially cutaway front view with some parts omitted.
Figure 14 is a sectional view in the direction of the arrow, and Figure 14 is XI-
A sectional view taken along the line XI and FIG. 15 shows a side milling cutter using the throw-away tip according to this invention.
A is a partially omitted plan view, and B is a partially omitted side view. 2...Throwaway tip, 11...Top surface,
12... Bottom surface, 13... Side surface, 14... Arc surface,
15... Notch, 16... Flat surface, 18... Cutting edge, 27... Convex curved surface, 29... Flat surface.

Claims (1)

[Scope of utility model registration request] The whole has a flat plate shape, and between the upper surface 11 and the lower surface 12, there is a flat side surface 13, and a substantially quarter-shaped arcuate surface 14 that is in contact with this side surface 13 and formed along the circumferential direction from there. It has two pairs of points symmetrically, and the upper surface 1 is between the side surface 13 of one pair and the circular arc surface 14 of the other pair.
A cutout portion 15 having a substantially V-shaped cross section extending from 1 to the lower surface 12 is formed, and of the two wall surfaces that define this cutout portion 15, the wall surface on the side surface 13 side is a flat surface 16. At the same time, the intersection of the upper end of the wall on the arcuate surface 14 side and the upper surface 11 is cut off to form a convex curved surface 27 whose upper end touches the upper surface 11, and the lower end of the wall on the arcuate surface 14 side is cut off. Curved surface 2
A cutting edge 18 is formed on the ridge formed by the convex curved surface 27 and the upper surface 11, the arcuate surface 14, and the side surface 13.
A throw-away tip characterized by forming.