JP2000190107A - Throw-away chip and cutting tool for thinning hole machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable machining for thinning hole with small dimensions without damaging the seating stability to a tool main body by making an included angle of both chip sides connected to a nose part larger than the tip end angle of the nose. SOLUTION: In all corner parts 13 of a chip 11, a single end part of one side surface 11C of two side surfaces 11C forming each corner part 13 is recessed from the surface to form a nose part 14 having a tip end angle αsmaller than an included angle β made between two side surfaces 11C, and further a cutting edge 14a is formed on the edge side of the tip end part of each nose part 14. Since the tip end angle and the included angle have the indepent relation geometrically, the included angle β is kept about 60 deg., and only the tip angle can be decreased according to the dimensions of a thinning hole. Accordingly, when the chip is mounted on the tool main body, the projection length of the nose part 14 is kept from being increased or the seating area is kept from being reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away insert (hereinafter simply referred to as an insert) for sneaking and a cutting tool provided with the insert.

[0002]

2. Description of the Related Art As a cutting tool for squeezing, a throw-away type boring bar provided with a solid solid type or rhombic plate-shaped insert is known. FIG. 10 shows a conventional example of a throw-away type boring bar used for processing small parts such as an injection nozzle of an automobile and a motor of a floppy (registered trademark) disk drive.

In this boring bar, a tip 3 having a cutting blade 2 is detachably mounted on a tip end of a tool body 1 having a cylindrical axis shape, and is rotated in a circumferential direction R as shown in FIGS. By giving a feed in the direction of arrow A to the workpiece W to be cut and making a cut in the direction of arrow B at a predetermined position while cutting the inner peripheral surface of the workpiece W, the inner peripheral surface processing and Can be performed simultaneously.

[0004]

However, due to the design restriction that the chip 3 has to form a much smaller sunk area on a small component, which is the work material W, the tip 3 has one diagonal direction. And the tip angle α of the nose portion is also narrow (for example, 35 °). For this reason, there has been a problem that the tip protruding length from the tool body 1 becomes unnecessarily long, and the seating surface performance with respect to the tip mounting seat 4 also becomes small, so that the tip 3 lacks seating stability.

When the clamping screw 5 is tightened, the tip of the boring bar is pressed diagonally rearward (toward the arrow C in FIG. 10), so that the seating performance is improved. The chip 3 is displaced. However, since the deviation increases as the tip 3 becomes slender in the diagonal direction, the deviation in the tip 3 increases, and it is difficult to adjust the position of the cutting edge.

Further, in the above-mentioned insert 3, since the nose portion 3a used for cutting can be formed only in two corners, there is a demand for extending the life of the insert by increasing the number of corners.

The present invention has been made in view of these circumstances, and an object of the present invention is to improve the seating stability of a chip and to realize a multi-corner nose portion.

[0008]

The present invention has the following features to attain the object mentioned above. The tip according to claim 1, further comprising a nose having a cutting edge at a corner of the tip body, and a tip angle α of the nose,
The relationship with the included angle β of both chip side surfaces connected to the nose portion is set so that α <β. In this configuration, the tip angle α of the nose portion and the included angle β of both chip side surfaces connected to the nose portion have a geometrically independent relationship. Therefore, the tip angle α of the nose portion can be appropriately narrowed in accordance with the size of the through hole to be machined without narrowing the included angle β on the side surface of the chip, thereby increasing the chip projection length and decreasing the seating surface performance. I can't.

A chip according to a second aspect of the present invention is the chip according to the first aspect, wherein the nose portion is formed at all corners of the chip body. With this configuration, all corners of one chip can be effectively used.

According to a third aspect of the present invention, there is provided a cutting tool wherein the tip according to the first or second aspect is detachably mounted on a tip mounting seat formed at a tip end portion of the tool body. Things. With this configuration, the tip can be mounted on the tool main body in a state where the protrusion length of the tip is small and the seating stability is high.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a chip according to a first embodiment of the present invention, and FIG. 2 is a side view of the chip. In these figures, reference numeral 11 denotes a chip (chip main body), and reference numeral 12 denotes a center portion thereof. The hole for inserting the clamp screw is shown.

The chip 11 is integrally formed into a triangular plate from a hard material such as a cemented carbide, and its upper and lower surfaces 11A and 11A are formed.
B is a rake face and a seating face, respectively. Further, as shown in FIG.
And the upper surface 11A are formed as a positive type chip having an acute angle.

Further, all the corner portions 13 of the chip 11
In one of the two side surfaces 11C forming each corner portion 13, one end of one side surface 11C is recessed from the surface, so that the tip angle α smaller than the included angle β formed by the two side surfaces 11C is reduced. The nose portion 14 is formed, and a cutting edge 14a is formed on the edge of the tip of each nose portion 14.

In FIG. 1, the tip angle α is 35 ° and the included angle β is 6
Although the chip 11 is set to 0 °, the chip according to the present invention is not limited to this. This is because the tip angle α should be appropriately set in accordance with the size of the recessed hole to be machined.

However, in the tip 11 of the present embodiment, since the tip angle α and the included angle β are geometrically independent of each other, the tip angle α is maintained at 60 ° while the included angle β is maintained at 60 °. Only α can be reduced according to the size of the through hole. Therefore, when the nose portion 14 is mounted on the tool body, the protruding length of the nose portion 14 does not become long and the seating area does not become small.

Next, a boring bar which is an embodiment of a cutting tool to which the above-mentioned tip 11 is mounted will be described with reference to FIGS.
4 will be described. The boring bar has a configuration in which the tip 11 configured as described above is detachably attached to a tip end of a tool body 15 having a cylindrical axis shape by a clamp screw 16.

At the tip of the tool body 11, a concave portion 17 is formed by cutting a part of the outer peripheral surface inward, and the concave portion 17 has a chip mounting portion which is further depressed one step from the outer peripheral surface. A seat 18 is formed. Tip mounting seat 18
Has two wall surfaces on which the two side surfaces 11C of the chip 11 are pressed when the chip 11 is seated and the clamp screw 16 is tightened.

When the chip is mounted, these wall surfaces form one side surface 11C of the chip 11 and the tool body 15
Is formed so that an angle (cutting edge angle) γ formed with a direction perpendicular to the axis L of the above-mentioned is 3 ° to 5 °. And chip 1
1 is mounted on the tip mounting seat 18 with the cutting blade 14a protruding toward the distal end side in the axial direction of the tool body 15 and radially outward.

However, since the boring bar of the present embodiment is provided with the insert 11 configured as described above, even if the recessed hole to be machined is extremely small, the boring bar can be formed in the radial direction of the tool body 15. It is possible to reduce the tip protrusion length to the outside, it is possible to correspond to the downsizing of prepared holes and downsizing of parts, and it is possible to suppress the decrease in seating area,
The seating stability of the tip 11 can be improved.

Further, the nose portion 14 used for cutting is provided.
However, since it is provided in all the corner portions 13 of the chip 11, in the present embodiment, three times of re-use by a corner change is possible. Therefore, the chip life can be extended 1.5 times as compared with the conventional boring bar which can be reused only twice.

Next, a tip and a boring bar according to a second embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. 5 is a plan view showing a chip according to the present embodiment, FIG. 6 is a side view of the chip, FIG. 7 is a plan view showing a main part of a boring bar to which the chip is mounted, and FIG. In these drawings, reference numeral 21 denotes a chip, and reference numeral 22 denotes a nose portion.

The chip 21 of the present embodiment is in the form of a parallelogram flat plate, and has a nose 2
2 are formed. In addition, a point that is integrally molded from a hard material, a point that is a positive tip, a nose portion 22
Is similar to the first embodiment in that the cutting edge 22a is formed on the ridge of the tip and the tool is mounted on the tool body 25 so that the cutting angle γ is 3 ° to 5 °.

As shown in FIG. 5, the nose portion 22 is formed so as to protrude from the acute-angled end of the long side surface 21A, and has two nose side surfaces 22A, 22 connected to the cutting blade 22a.
B, one nose side surface 22B is the short side side surface 21B.
And the other nose side surface 22A intersects with the long side surface 21A. Accordingly, the relationship between the tip angle α of the nose portion 22 and the included angle β of the long side surface 21A and the short side surface 21B is α <β.

In FIG. 5, the tip angle α is 35 ° and the included angle β is 8
Although the tip 21 is set at 0 °, the tip angle α and the included angle β are also geometrically independent of each other in the chip 21 of the present embodiment, and thus the included angle β is set to 80 °. While holding, only the tip angle α can be reduced according to the size of the clearance hole.

Therefore, if the chip 21 is mounted on the tool body 25 having the same structure as described above to form a boring bar as shown in FIG. 7, the same operation and effect as described above can be obtained for the boring bar.

In this embodiment, as in the conventional boring bar, the nose portion 22 can be reused only twice by changing the corner. However, as is clear from FIG.
Since the tip protrusion length is greatly reduced and the ratio of the seating area to the seating surface is also greatly increased, the seating stability can be dramatically improved.

Next, a third embodiment of a chip according to the present invention and a boring bar to which the chip is mounted will be described with reference to FIG. Chip 31 according to the present embodiment
Is characterized in that it has four corner portions 32 and nose portions 33 are formed in all the corner portions 32. In addition, about the point which is integrally molded from a hard material, the point which is a positive tip, the point where the cutting edge 33a is formed at the tip edge of the nose part 33, etc.
This is the same as each of the above embodiments.

The nose portion 33 has chip side surfaces 31A to 31A.
D has a shape in which the middle portion is depressed toward the side surface facing each other, and taking the corner portion 33 located at the lower left of FIG. 9 as an example, two nose side surfaces 33A connected to the cutting edge 33a will be described. , 33B, one nose side surface 33B extends along one chip side surface 31B, and the other nose side surface 33A crosses the other chip side surface 31A. Thus, the relationship between the tip angle α of the nose portion 33 and the included angle β of both the chip side surfaces 31C forming the corner portion 32 is α <β.

Therefore, if the tip 31 is mounted on the tool body 35 having the same structure as above and a boring bar as shown in FIG. 9 is formed, the same operation and effect can be obtained also with this boring bar. In particular, in the present embodiment, since the nose portion 33 can be reused four times due to a corner change, compared to a conventional boring bar,
The chip life can be doubled.

[0030]

As described above, according to the present invention, the following effects can be obtained. (A) According to the chip of the first aspect, only the tip angle β of the nose portion can be appropriately narrowed in accordance with the size of the recessed hole to be machined without narrowing the included angle α on the side surface of the chip. A small hole can be machined without impairing the seating stability of the tool body.

(B) According to the chip of the second aspect, since all the corner portions of one chip can be used effectively, the number of times of reusing the nose portion due to the corner change increases, and the chip has a long life. Is achieved.

(C) According to the cutting tool of the third aspect,
Since the tip protruding length can be reduced and the decrease in the seating area can be suppressed, it is possible to provide a cutting tool that has high seating stability, and can cope with downsizing of the pilot hole and downsizing of components.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of a chip according to the present invention.

FIG. 2 is a side view of the chip shown in FIG.

FIG. 3 is a plan view showing a main part of a boring bar including the chip shown in FIG. 1;

FIG. 4 is a front end view of the boring bar shown in FIG. 3;

FIG. 5 is a plan view showing a second embodiment of the chip according to the present invention.

FIG. 6 is a side view of the chip shown in FIG. 5;

FIG. 7 is a plan view showing a main part of a boring bar provided with the chip shown in FIG. 5;

FIG. 8 is a front end view of the boring bar shown in FIG. 7;

FIG. 9 is a main part plan view showing a third embodiment of the boring bar according to the present invention.

FIG. 10 is a plan view of a main part showing a conventional example of a boring bar.

FIG. 11 is a front end view of the boring bar shown in FIG. 10;

12 is a cross-sectional view showing a state where a work material is being processed using the boring bar shown in FIG.

[Explanation of symbols]

 11, 21, 31 Tip 11C, 21C, 31C Side surface 13, 23, 32 Corner portion 14a, 22a, 33a Cutting edge 14, 22, 33 Nose portion 15, 25, 35 Tool body 18 Tip mounting seat α Inclusion angle β Tip angle

Claims (3)

[Claims] 1. A corner portion of a tip body has a nose portion with a ridge formed as a cutting edge, and a relationship between a tip angle α of the nose portion and an included angle β of a tip side surface connected to the nose portion is as follows. A throw away tip characterized by being set to α <β. 2. The chip according to claim 1, wherein the nose portion is formed at all corners of the chip body.
The described throwaway tip. 3. A cutting tool, wherein the indexable tip according to claim 1 or 2 is detachably mounted on a tip mounting seat formed at a tip portion of the tool main body.