JPS6140412Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a throw-away type cutter in which a plurality of polygonal cutting tips are detachably attached to the outer periphery of the cutter body.

Conventionally, as shown in FIGS. 1 to 4, this type of cutter has a tapered portion 1a formed on the outer periphery of the tip of the cutter body 1, the diameter of which gradually increases from the tip to the rear end. A plurality of rectangular cutting tips are tightened and fixed on the outer periphery of the tip of this tapered part with tightening bolts 4 via wedge members 3, and a plurality of square cutting tips are tightened and fixed along the rake surface 2a of the cutting tip 2 from the tip side. There is a face milling cutter formed with a tip pocket 5 extending toward the rear end. In this case, the tip pocket 5 has an arcuate surface on its bottom surface, and a line connecting the centers of curvature of the arcuate surface is parallel to the generatrix of the tapered portion 1a.

In such a face milling cutter, in order to prevent cutter vibration, chipping of the cutting tip 2, or deterioration of the finished surface due to poor chip evacuation,
It is desired that chips be quickly discharged from the tip pocket 5 to the outside. For this reason, in face milling, the cutting tip 2 is generally aligned with the axis O of the cutter body 1 as the straight portion 2b, which is the main cutting edge, goes from the tip side to the rear end side of the cutter body 1.
The chips are arranged so as to be gradually spaced apart from each other, thereby reducing the thickness of the chips and improving their evacuation performance. However, it is difficult to say that such a reduction in chip thickness alone is sufficient to obtain good chip evacuation properties.

For example, as shown in FIG. 5, there is a face milling cutter in which a new tip pocket 6 is formed at the end of the tip pocket 5 in the direction of cutter rotation to increase the overall width of the tip pocket. The width of the part of the main body 1 that supports the back of the cutting tip 2, the so-called width W of the back metal M
(see FIG. 2) decreases, and the rigidity of the cutter body 1 decreases. For this reason, light cutting has to be performed, and cutting efficiency is forced to decline.

On the other hand, if the number of cutting blade tips 2 is reduced in order to increase the width of the tip pocket 5 without reducing the rigidity of the cutter body 1, the cutter 1
The amount of feed per revolution has to be reduced, which also causes a decrease in cutting efficiency.

This invention was made in consideration of the above circumstances, and an object of the present invention is to provide a throw-away type cutter that can improve chip evacuation performance without reducing the rigidity of the cutter body or reducing the number of cutting edges. With the goal.

The feature of this invention is that the cutting tip is arranged so that the straight part, which is the main cutting edge, is gradually separated from the axis of the cutter body as it goes from the tip side to the rear end side of the cutter body. Focusing on the fact that the width of the back metal gradually increases from the tip to the rear, we designed the tip pocket so that its cross-sectional area gradually increases from the tip to the rear. The concavity forming the tip pocket is formed by gradually increasing the width and depth, and the ridge line of the concave curved surface of the tip pocket in contact with the rake surface of the cutting blade tip is parallel to the straight part that is the main cutting edge. It is formed by gradually shifting the center of curvature of the curved surface from the tip to the rear end in the direction of rotation and toward the axis.

An embodiment of this invention will be described below with reference to FIGS. 6 to 11. In these figures, FIG. 6 is a half-sectional view of the face milling cutter according to this invention, FIG. 7 is a partially omitted view of FIG. 6, FIG. 8 is a view of FIG. 6, and FIG. is a view taken along the arrow in FIG. 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.

The bottom surface 15a of the chip pocket 15 is formed by a curved surface with a radius of curvature R. here,
If the center of curvature of the portion located at the tip of the tapered portion 1a of this curved surface is P, and the center of curvature of the portion located at the rear end is Q, then the center of curvature Q is located in the rotation direction with respect to the center of curvature P. Distance X to the other side,
They are each shifted by a distance Y toward the axis O side,
The center of curvature between the centers of curvature P and Q is the center of curvature P and Q
It is located on the straight line connecting the That is, a line connecting the centers of curvature of the curved surfaces forming the tip pocket 15 is located at the front end in the rotational direction and the axis O as it goes from the tip side to the rear end side with respect to the generatrix of the tapered portion 1a.
It is slanted towards the side. As a result, the width and depth of the tip pocket 15 gradually increase from the distal end to the rear end of the cutter body 1, and its cross-sectional area also gradually increases.

Also, in contact with the rake surface 2a of the cutting blade tip 2,
Ridge line 15b of bottom surface 15a of chip pocket 15
The distance X and Y between the centers of curvature P and Q of the concave curved surface forming the tip pocket 15 is set toward the front side in the rotational direction from the tip to the rear end so that the tip pocket 15 is a straight line parallel to the straight part 2b, which is the main cutting edge. It is formed by gradually shifting toward the axis O side. Therefore,
The width L from the cutting load acting portion (straight line portion 2b) to the cutting load supporting portion (ridgeline 15b) is equal from the leading end to the trailing end of the cutting tip 2, as shown in FIG. This means that the implantation depth of the cutting blade tip 2 into the tip seat is equal on the front end side and the rear end side. Thereby, the cutting load during cutting can be equally received at any part of the straight portion 2b which is the main cutting edge of the cutting blade tip 2 (from the leading end to the trailing end). As a result, the seating stability of the cutting tip 2 can be improved, chipping of the cutting edge can be prevented, and the finish of the cut surface can be improved.

However, in such a face mill, the cross-sectional area of the tip pocket 15 gradually increases from the tip side to the rear end side, so the volume of the tip pocket 15 is increased to improve chip evacuation. You can improve your performance. especially,
When cutting is performed with a face milling cutter, the chips generated by the straight portion 2b of one cutting edge tip 2 are thinner on the biting side and the exiting side, and are thinner in the middle between these. It is thicker at the tip of the cutter in the cutting direction. Therefore, in the withdrawal side cutting process, as shown in FIGS. 10 and 11, the part of the chip T that is thick and has a large curl radius is located on the rear end side of the chip pocket 15. . For this reason, with conventional cutters, it is difficult to avoid deterioration of chip evacuation performance, but with the throw-away type cutter of this invention, the chip pocket 1
Since the cross-sectional area on the rear end side of the tip 5 is increased, the chips T can be smoothly discharged to the outside. Further, since the cross-sectional area of the tip pocket 15 increases toward the rear end side, the contact area of the chips T with the bottom surface 15a is reduced accordingly.
It is possible to reduce the frictional resistance caused by the chips T, and thus the cutting resistance. Furthermore, by reducing the contact area of the chips T with the bottom surface 15a, the cutter body 1 is prevented from deforming the cutter body 1 and the cutting heat transmitted from the chips T to the cutter body 1.
It is possible to reduce the deterioration of the material and improve its lifespan. Moreover, the cutting blade tip 2 is arranged so that the straight part 2b, which is the cutting edge, is gradually spaced apart from the axis O of the cutter body 1 as it goes from the tip side to the rear end side of the cutter body 1. Above, since the width of the back metal M gradually increases from the distal end to the rear end, even if the cross-sectional area of the tip pocket 15 is gradually increased toward the rear end, the rigidity of the cutter body 1 will not decrease. No problem.
Furthermore, since the rigidity of the cutter body 1 is not reduced, there is no need to reduce the number of cutting blade tips 2 in order to increase the volume of the tip pocket 15.

In addition, the throw-away type cutter shown in FIGS. 12 to 13 has a shank portion 1a integrally formed on the rear end side of the cutter body 1 so as to be suitable for use in a machining center, etc. This is a face milling cutter with a shank in which a groove 18 extending from the tip to the rear end of the tip pocket 15 is formed in the center of the bottom surface 15a in order to further reduce the contact area. This groove 1
8 is defined by a bottom surface having a concave curved surface, and extends in substantially the same direction as the chip pocket 15. Due to the presence of this groove 18, the depth of the chip pocket becomes deeper, and the contact area of chips T can be reduced, so that cutting resistance can be further reduced.

In each of the above embodiments, this invention is applied to a face milling cutter, but the present invention is not limited thereto, and can be applied to, for example, a half side cutter.

Further, in each of the above embodiments, the cutting edge tip 2 has a rectangular shape, but is not limited to this, and may have other polygonal shapes such as a pentagonal shape or a hexagonal shape.

As explained above, according to the throw-away type cutter of this invention, the width and depth of the tip pocket are gradually increased so that the cross-sectional area thereof gradually increases from the tip to the rear end. Since the cutter body is formed with the same structure, it is possible to improve chip evacuation without reducing the rigidity of the cutter body or reducing the number of cutting edges, and it is also possible to reduce cutting resistance and extend the life of the cutter body. Effects such as this can be obtained. In addition, the ridgeline on the bottom of the tip pocket that touches the rake surface of the cutting edge tip is configured to be a straight line parallel to the straight section that is the main cutting edge, so that the cutting load is The width to the support part (ridge line) of the tip is the same from the tip to the rear end, and as a result, the seating stability of the cutting edge tip is good, and as a result, it is possible to prevent chipping of the cutting edge, and also to prevent the cutting edge from being damaged. It is possible to improve the finish of the machined surface.

[Brief explanation of the drawing]

Figures 1 and 2 show an example of a conventional throw-away type cutter. Figure 1 is a partially omitted vertical cross-sectional view taken along the - line arrow in Figure 2, and Figure 2 is a partially omitted view of Figure 1. 3 shows a partially omitted view of Fig. 1, Fig. 4 shows a partially omitted view of Fig. 3, and Fig. 5 shows another example of a conventional throw-away cutter. Figures similar to Figure 4 and Figures 6 to 11 show an embodiment of this invention; Figure 6 is similar to Figure 7;
7 is a partially omitted longitudinal cross-sectional view of FIG. 6 as viewed from the line, FIG. 8 is a partially omitted view of FIG. Part omitted view, 1st
Figures 0 and 11 show the state of chip discharge, respectively, with Figure 10 being the same as Figure 6, Figure 11 being the same as Figure 8, and Figures 12 to 14 showing the state of discharge of chips. FIG. 12 is a partially cutaway front view of another embodiment, FIG. 13 is a partially cutaway view of FIG. 12, and FIG. 14 is a partially omitted view of FIG. 1... cutter body, 2... cutting blade tip, 2a...
...Rake face, 2b...Straight section, 15...Tip pocket, 15a...Bottom surface, 15b...Ridge line, O...
...axis line.

Claims (1)

[Claims for Utility Model Registration] 1. A plurality of polygonal cutting blade tips 2 are provided on the outer periphery of the cutter body 1, and a linear portion 2 is used as the main cutting edge.
b are arranged and detachably mounted so as to be gradually spaced apart from the axis of the cutter body 1 from the tip side to the rear end side of the cutter body 1, and are adjacent to the rake face 2a of the cutting blade tip 2. In the indexable cutter, a tip pocket 15 is formed on the outer periphery of the cutter body 1, and the tip pocket 15 extends from the tip end to the rear end side of the cutter body 1. The ridgeline 15b of the concave curved surface of the tip pocket 15 that is in contact with the rake surface 2b of the cutting blade tip 2 is formed so that the width and depth thereof gradually increase toward the end. It is formed by gradually shifting the center of curvature of the concave curved surface forming the tip pocket 15 from the tip to the rear end in the forward direction of rotation and toward the axis so that it is parallel to the straight portion 2b that is the blade. A throw-away cutter that is characterized by: 2 The chip pocket 15 has its bottom surface 15a
The throw-away type cutter according to claim 1, wherein the cutter has a groove 18 extending in substantially the same direction as the tip pocket 15 and having a concave curved surface.