JPH09290312A - Throwaway tip and throwaway type drilling tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip suitable for using as the cutting edge of a drilling tool, especially and a drilling tool suitable for using this tip. SOLUTION: In the one end 16A of a cutting edge 16 formed on the side ridge of the cutting face 13 of a tip main body 12, a face 13 is formed on a projection surface 18 sunk gradually facing to the seat surface 14 side of the tip main body 12 as heading for one end 16a side of the cutting edge 16 and also a slant surface 20 cut up facing to the plane part 19 of the face 13 as separating from the projection surface 18 is formed in a side opposite to the cutting edge 16 of this projection surface 18. This tip 11 is used as the inner circumferential side chip of the drilling tool by nearly positioning one end 16a of the cutting edge 16 on the center axis O of the tool main body. The rotation locus Q of the cutting edge of the outer periphery side tip is crossed to the other end 16b of the cutting edge 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is particularly suitable for a throw-away tip (hereinafter,
It is called a chip. ), And a throw-away type drilling tool (hereinafter referred to as a drilling tool) equipped with the tip.

[0002]

2. Description of the Related Art Generally, it is well known that chips are generated when cutting metal or non-ferrous metal. In order to efficiently obtain the required shape, size, accuracy, etc. by processing the work material as the first purpose, how to generate and control these chips that are ultimately unnecessary Stable, safe, and reliable processing is often the key to achieving this goal. In response to the demands of the times such as high speed, high efficiency, unmanned operation, continuous operation, safety and health accompanying the progress of cutting technology, such chip disposal has become an indispensable technology. Therefore, various chips having various chip disposal functions have been proposed accordingly.

FIGS. 14 and 15 and FIGS. 16 and 17 show a chip provided with such a chip disposal function by forming a chip breaker, respectively. Chip 1 shown in FIGS. 14 and 15 is shown. In the above, a cutting edge 3 is formed on each side edge of one triangular surface which is the rake surface 2A of the chip body 2 in the shape of a substantially triangular flat plate, and the cutting edge 3 is recessed on the rake surface 2A along the cutting edge 3. A groove-shaped chip breaker 4 is formed. 16 and 1
In the chip 5 shown in FIG. 7, a chip breaker 8 having a protruding shape is formed inside the cutting edge 7 of the rake face 6A of the chip body 6.
Is formed so as to undulate in a plan view along the cutting edge 7. Then, in the chip 1, the chips generated by the cutting blade 3 are subjected to stress due to friction while being slidably contacted with the bottom surface of the grooved chip breaker 4 to be rounded and divided, and in the chip 5, The chips generated by the cutting blade 7 are subjected to stress when riding on the projecting chip breaker 8, and are also rounded and divided.

[0004]

However, various factors are involved in the process of producing chips, and the uniform solution means that chips produced in various shapes based on such various factors. Can't deal with. For example, the factors include the material of the work material, the hardness, the material of the cutting tool, the form of the cutting tool, the form of the cutting edge of the cutting tool, the friction coefficient, the cutting condition, the presence or absence of the cutting fluid, the component, the pressure and the capacity. , Strictly considering the structure and rigidity of the machine, there is no choice. However, in the above-mentioned conventional tips 1 and 5, the cutting edges 3 and 7 are
On the other hand, since the chip breakers 4 and 8 are uniformly formed, the action of the chip breakers 4 and 8 on the chips generated by the cutting blades 3 and 7 is also uniform, and the chip generation process described above is performed. There is a possibility that it may be difficult to properly deal with a complicated factor related to.

Further, particularly in the case where the tool is a drilling tool for making a hole in a work material, severer conditions are added than those in the form of machining by other cutting tools. For example, one is that in cutting with such a drilling tool, chips are generated at the bottom of the drilled hole in which the tool body is inserted,
The chip discharge space (space) is limited, and chips must be quickly and smoothly discharged from the inside of the processed hole. In such hole machining, if such a condition is not sufficiently satisfied, the chips will be clogged in the machined holes and immediately become impossible to machine, and in some cases, the tool will be damaged.

The present invention has been made under such a background, and a purpose thereof is to enable one chip to deal with chips whose production process is variously changed by various factors. In particular, it is to provide a suitable tip for use as a cutting edge portion of a drilling tool, and to provide a suitable drilling tool using the tip.

[0007]

In order to solve the above problems and to achieve the above object, in a chip according to claim 1 of the present invention, one polygonal surface of a chip body having a polygonal flat plate shape is scooped. And a chip having a cutting edge formed on the side edge portion of the rake surface, and at one end of the cutting edge, as the rake surface moves toward the one end side of the cutting edge, It is formed on a convex surface that gradually dents toward the other polygonal surface side, and on the side opposite to the cutting edge of this convex surface, it is cut toward the rake surface as it is separated from the convex surface. It is characterized in that a rising slope is formed.
Therefore, one end of the cutting edge is formed in a convex shape along the convex surface, so that the chips generated by the one end of the cutting edge are stretched in the width direction during generation. As described above, when the convex surface is rubbed against the inclined surface, it is rounded in the longitudinal direction to receive the stress, and is effectively divided.

[0008] Here, if the inclined surface is formed so as to be convex along the convex surface toward the other polygonal surface side toward the one end side of the cutting edge, the chips are Even when the inclined surface is rubbed, stress is applied in the width direction, and it is possible to achieve a more efficient chip separation process. Further, in the cross section orthogonal to the convex surface, the inclination angle formed by the inclined surface with respect to the direction perpendicular to the convex surface is 2
It is desirable to set in the range of 5 ° to 65 °. this is,
If the inclination angle exceeds the range and the inclination surface is gentle, it may not be possible to apply sufficient longitudinal stress to the chips. Conversely, if the inclination angle decreases below the range, the inclination surface becomes steeper. This is because chips may collide with each other, which may lead to an increase in the load acting on the chip and the tool. Further, if the convex surface is formed so as to be gradually depressed toward the other polygonal surface side as it is separated from the cutting edge, the rake angle of the cutting edge at the one end is greatly increased to the regular angle side. By doing so, it is possible to reduce the cutting resistance and increase the longitudinal stress applied to the chips when riding on the inclined surface from the convex surface.

On the other hand, a drilling tool according to a fifth aspect of the present invention is a drilling tool in which tips are detachably mounted on an inner peripheral side and an outer peripheral side of a tip portion of a tool body, respectively.
The chip according to claim 1 is used for the inner peripheral side chip, that is, the inner peripheral side chip has one polygonal surface of a polygonal plate-shaped chip body as a rake face,
As a chip in which a cutting edge is formed on the side edge of this rake face, at one end of the cutting edge, the other polygonal surface side of the chip body is moved toward the one end side of the rake face. Is formed on a convex surface that gradually depresses toward, and on the opposite side of the convex surface from the cutting edge, an inclined surface that rises toward the one polygonal surface as it is separated from the convex surface. And the tip on the inner peripheral side is made to project the cutting edge toward the tool tip side, the rake face is directed toward the tool rotation direction side, and the cutting edge of the cutting edge is seen from the direction facing the rake face. It is characterized in that one end is arranged so as to be substantially positioned on the central axis of the tool body.

According to the drilling tool having such a structure, however, the convex surface and the inclined surface which are continuous with one end of the cutting edge of the inner peripheral side tip arranged near the axis of the tool body are preferable. As in the case of the chip according to (1), chips can be reliably and efficiently divided and processed. Moreover, in this type of drilling tool, the cutting speed is different between the inner circumference side and the outer circumference side of the tool main body, so that cutting that crushes the work material especially near the axis (rotation center) of the tool main body Therefore, the cutting load acting on the cutting edge tends to increase, whereas in the inner tip, one end of the cutting edge located near this axis is formed in a convex shape. As a result, the strength of the cutting edge can be improved, so that it is possible to secure sufficient cutting edge strength even with respect to the above-mentioned increasing cutting load and prevent occurrence of defects and the like.

When the tip according to claim 1 is used as the tip on the inner peripheral side as described above, the tip body is formed in a regular polygonal flat plate shape and is formed on each side ridge portion of the rake face. The cutting edge is formed, and the other end of each cutting edge is an intersection of the side ridge portion where the cutting edge is formed and the inclined surface formed on the one end side of the cutting edge adjacent to the cutting edge. On the other hand, the tip on the outer peripheral side of the tool body has its cutting edge projected toward the tool tip side, and the rotation locus of the cutting edge is the cutting edge protruding toward the tool tip side of the inner circumference side tip. It is desirable that they are arranged so as to substantially intersect the other end.
However, by adopting such a configuration, the convex surface and the inclined surface of the adjacent cutting blades adjacent to the outer peripheral side (the other end side) of the cutting blades used for cutting the inner peripheral side tip have a rotational trajectory. Since it is arranged on the tool rear end side with respect to the cutting edge of the tip on the outer peripheral side, it is possible to avoid these convex surfaces and inclined surfaces from being involved in cutting, and therefore, in the tip on the inner peripheral side, Since it is possible to form the largest number of cutting edges on the rake face having a polygonal shape, it is possible to improve the chip utilization efficiency.

[0012]

1 to 5 show one embodiment of the chip of the present invention. The chip 11 according to the present embodiment has a chip body 12 formed of a hard material such as cemented carbide into a substantially square flat plate appearance, and has a substantially square top surface (one square surface).
And the lower surface (the other square surface) opposite to the rake surface 13 is the seating surface 14, and the four side surfaces between the rake surface 13 and the seating surface 14 are open. Surface 15 ... and the above-mentioned rake surfaces 13 and 4
Ridge line crossing with two flanks 15, ie rake face 1
The cutting edges 16 are formed at the four side edges of No. 3 respectively. The chip 11 of the present embodiment is a positive chip in which the flanks 15 have a clearance angle γ, and the clearance angle γ is preferably set to 0 ° to 25 °. However, when the clearance angle γ is 0 °, the chip 11 is a negative chip. Also, the above rake face 1
From the center of 3 to the seating surface 14, a mounting hole 17 through which a clamp screw for mounting the chip 11 to a tool body such as a drilling tool is inserted is provided.

In the present embodiment, at one end 16A of each cutting edge 16 formed on the four side ridges of the rake face 13, one end 16a of the cutting edge 16 is attached to the rake face 13.
A convex surface 18 is formed that is convexly curved outward of the chip body 12 as it goes to the side, and is gradually depressed toward the seating surface 14 side. In the present embodiment, the convex surface 18 is formed as a cylindrical surface having a central axis parallel to the flat surface portion 19 of the rake surface 13 and smoothly connected to the flat surface portion 19, and thus the convex surface 18 is formed. One end portion 16A of the cutting edge 16 formed at the ridge line portion of the intersection of the flank 18 and the flank 15 is as shown in FIG. 3 when viewed from the direction facing the flank 15, that is, the direction along the central axis. It will be curved and formed into an arcuate convex curve having a radius R.

On the other hand, the other end portion 16B of the cutting edge 16 formed at the ridge line intersecting with the flat surface portion 19 of the rake face 13 and the flank surface 15 is smooth on the one end portion 16A of the arc shape. Is formed so as to extend linearly toward the other end 16b of the cutting edge 16, and the intersection line S between the convex surface 18 of the rake surface 13 and the flat surface portion 19 is formed in this embodiment. The other end 16B of the straight cutting edge 16 and one end 16A of the convex curved line extend from the intersection 16c perpendicularly to the other end 16B. When the tip 11 is a positive tip as in the present embodiment, one end 16A of the cutting edge 16 has one end 16A in plan view from the rake face 13 side as shown in FIG.
As it goes toward the a side, it is curved and formed so as to recede while drawing a convex curve.

Further, in the rake face 13, on the side opposite to the one end portion 16A of the cutting edge 16 with the convex face 18 interposed therebetween, the cutting face 16 is connected to the convex face 18 and the convex face 18 is formed. A sloping surface 20 is formed so as to increase toward the flat surface portion 19 of the rake surface 13 as the distance from the side increases.
Here, in the present embodiment, the inclined surface 20 extends from the flat surface portion 19 side toward the one end 16a side along the direction in which the one end portion 16A of the cutting edge 16 curves, and thus the convex surface 18 is formed.
It is formed in a substantially conical surface shape that is concave and forms a convex shape on the seating surface 14 side so as to follow.

The inclined surface 20 is the convex surface 18
As shown in FIG. 5, the inclination angle θ with respect to the direction perpendicular to the convex surface 18 in a cross section orthogonal to the cross section, that is, in the cross section including the central axis of the cylindrical surface formed by the convex surface 18.
Is set to fall within the range of 25 ° to 65 °. Further, in the present embodiment, the other end 16b of each cutting edge 16
Is a side edge of the rake face 13 on which the other end 16B of the cutting edge 16 is formed, that is, the rake face 1 continuous with the cutting edge 16.
3, the intersection of the ridge line intersecting the flat surface portion 19 and the flank surface 15 and the inclined surface 20 formed on the one end portion 16A side of the cutting blade 16 adjacent to the cutting blade 16, that is, the flat surface portion 19 and the flank surface. It is located at the intersection with the inclined surface 20 intersecting with 15.

The intersection line B formed by the convex surface 18 and the inclined surface 20 connected to the convex surface 18 is recessed toward the seating surface 14 as shown in FIG.
It is formed so as to gradually approach the A side, and by this and the one end portion 16A of the cutting edge 16 being curvedly formed in a plan view as described above, the width W of the convex surface 18 is The width becomes gradually narrower as it goes toward the one end 16a side along 16. However, in this embodiment, the width W of the convex surface 18 is
Is set to be in the range of 0.8 mm to 5.0 mm. Further, strictly speaking, the portion of the intersection line B formed by the convex surface 18 and the inclined surface 20 is smoothly connected by a concave curved surface having an arcuate cross section as shown in FIG. It is set in the range of 0.2 mm to 3.0 mm. Further, in this embodiment, the thickness T of the chip body 12 is 2.38 m.
While the height is from m to 6.35 mm, the height t from the seating surface 14 to the one end 16a of the cutting edge 16 is set to T / 3 or less. However, t = 0 may be set so that the one end 16 a coincides with the seating surface 14.

Furthermore, in this embodiment, the width L of the tip body 12 (the other end portion 17 of the cutting blades 17, 17 formed on a pair of side ridges located on the opposite sides of the rake face 13).
(Distance between B and 17B) is set in the range of 6.35 mm to 19.05 mm, while in the width L direction when viewed from the direction facing the flank 15 as shown in FIG. From the other end 18B of the other cutting edge 16 adjacent to the one end 16a side of the one cutting edge 16 formed on the flank 15 to the intersection 16c of the one end 16A and the other end 16B of the one cutting edge 16 L ₁ and the width L of the other end 16B of the one cutting edge 16
₂ and the other end 16b of the one cutting edge 16 from the other end 16b
The width L ₃ to the other end portion 16B of the other cutting edge 16 adjacent to the side divides the width L into three equal parts, that is, the widths L ₁ , L ₂ , L ₃ = L / It is set to be 3. However, the widths L ₁ , L ₂ , and L ₃ may be unequal, but the minimum value among them is L /
It is desirable to set it so as not to fall below 5.

As shown in FIGS. 5 and 6, the tip 11 having such a structure is mounted on a tip mounting seat 22 formed at the tip of a tool body 21 having a substantially cylindrical shape, and is used in the drilling tool of the present invention. It constitutes an embodiment. Here, a pair of tip mounting seats 22 and 22 are formed at the tip of the tool body 11 on the inner peripheral side and the outer peripheral side with respect to the central axis O, and the tip 11 has a tip mounting seat on the inner peripheral side thereof. 4 attached to the rake face 13 of the rake face 13
One of the two cutting blades 16 is projected toward the tool tip side, the rake surface 13 is directed toward the tool rotation direction, and as shown in FIG. One end 16a of 16 is arranged on the central axis O. In addition, this chip 11
As shown in FIG. 6, the other end portion 16B of the cutting edge 16 protruding toward the tool tip side is inclined toward the tool rear end side at an angle α set in the range of 1 ° to 10 ° toward the tool outer peripheral side. The cutting edge 16 is arranged so that one end portion 16A thereof projects most toward the tool tip side. Further, as a result, the cutting edge 16 is cut from the axis O.
The width L ₄ to the other end 16b of the cutting edge 16 is smaller than the width (length) L ₁ + L ₂ of the cutting edge 16 in plan view of the tip 11.

On the other hand, as the tip 23 to be attached to the tip attachment seat 22 on the outer peripheral side, in the present embodiment, a well-known square flat plate in which cutting edges 24 are formed at each of four side ridges of the substantially square rake face is used. Chips are used. Then, the tip 23 on the outer peripheral side has the one cutting edge 24.
Is extended from the position away from the axis O so as to protrude to the outer periphery of the tool body 21 and protrudes toward the tool tip side, and as shown in FIG. 7, the rotation locus Q of the cutting edge 24 around the axis O is It is arranged so as to intersect with the other end 16b of the cutting edge 16 projecting toward the tool tip side of the tip 11 on the inner peripheral side. It should be noted that a clearance angle ε is given to the side ridge portion of the rake face of the tip 23 on the outer peripheral side located on the tool outer peripheral side as shown in FIG. 6, and the clearance angle ε is 0 in the present embodiment. It is set in the range of 10 'to 8'00'. Further, reference numeral 25 in the drawing denotes a chip discharge groove formed on the outer periphery of the tool body 21 so as to extend from the tool tip toward the rear end side.

However, in the tip 11 having the above structure, the one end portion 16A of the cutting edge 16 has the convex surface 1 as described above.
8 is curved to form an arc-shaped convex curve,
Also, as shown in FIG. 8, the chips C ₁ generated by the one end portion 16A of the cutting blade 16 are also curved in a convex shape in the width direction, and at that time, the chips C ₁ are stretched in the width direction. Will be stressed. Then, the chips C ₁ thus generated further rub against the convex surface 18 and ride on the inclined surface 20 formed behind the convex surface 18, and at that time, as shown in FIG.
As shown in ( ₁₎ , the chips C ₁ are also rolled in the longitudinal direction to receive the stress, so that the chip C ₁ is torn and divided by the stress in the width direction and the stress in the longitudinal direction. Therefore, according to the chip 11, it becomes possible to quickly divide the generated chips C ₁ after the generation thereof, which makes it efficient even for chips whose generation process changes variously due to various factors. It becomes possible to promote smooth cutting by taking measures. In addition, what is indicated by reference numeral C ₂ in FIGS. 7 and 8 is a chip generated by the cutting edge 24 of the tip 23 on the outer peripheral side in the drilling tool of the above-described embodiment.

Further, in the chip 11 of this embodiment, the inclined surface 20 continuous with the convex surface 18 has the convex surface 1
It is formed so as to be depressed in a convex shape along the convex surface 18 as it goes toward the one end 16a side of the cutting blade 16 in which 8 is continuous, and therefore the chips C generated by the one end 16A of the cutting blade 16 are formed. _{In No. 1} , when riding on the inclined surface 20 and rubbing against it, stress is applied not only in the longitudinal direction but also in the width direction. That is, since the chip C ₁ is subjected to the stress in the width direction on the convex surface 18, and further receives the stress in the longitudinal direction and the stress in the width direction on the inclined surface 20, according to the present embodiment, It becomes possible to surely promote the division of the chips and to achieve more efficient processing.

Further, the inclined surface 20 in the present embodiment.
In the cross section orthogonal to the convex surface 18 as shown in FIG. 5, the inclination angle θ formed with respect to the direction perpendicular to the convex surface 18 is set in the range of 25 ° to 65 °. Therefore, while exerting a sufficient longitudinal stress on the generated chips C ₁ , it is possible to avoid an excessive load from acting on the tip 11 and the tool due to the reaction thereof. That is, when the inclination angle θ becomes larger than 65 °, the inclination of the inclined surface 20 with respect to the convex surface 18 becomes too gentle, and as a result, the chip C ₁ may be given a sufficient longitudinal stress sufficient for division. It may become difficult, and conversely the tilt angle θ is 2
If it is smaller than 5 °, the inclined surface 20 is formed so as to stand upright with respect to the convex surface 18, and the convex surface 1
The chip C ₁ that has rubbed 8 may collide with the inclined surface 20 from the front, and an excessive impact load may be applied to the tip body 12 and the tool body 21.

On the other hand, in the drilling tool of one embodiment of the present invention equipped with the tip 11 having such a structure, the tip 11 of the above embodiment causes the one cutting edge 16 to project toward the tool tip side, and It is arranged so that the rake face 13 faces the tool rotation direction side and the one end 16a of the one cutting edge 16 is located on the central axis O of the tool body 21 when viewed from the direction facing the rake face 13. Therefore, the convex surface 18 continuous with the one end 16A of the one cutting edge 16
Further, the inclined surface 20 makes it possible to reliably divide the chips and achieve efficient processing. Therefore, even in the case of drilling to which particularly severe conditions are added as described above, according to the drilling tool of the present embodiment, it is possible to prevent the generated chips from being clogged in the drilled hole. It is possible to perform smooth, stable, and highly accurate processing.

In the tip 11, the cutting edge 1
By forming the convex surface 18 on the one end portion 16A of 6, the one end portion 16A of the cutting edge is also curved in a convex shape, and in the drilling tool of the present embodiment, the tip 11 is Since the one end 16a of the cutting blade is mounted with the one end 16a positioned on the axis O, the cutting blade 16 has a convex one end 16A that is gradually cut into the work material from the one end 16a side during machining. In particular, one end 1 of the cutting edge 16
It is possible to avoid impacting 6A,
Since the cutting edge 16 is given a negative radial rake angle, the cutting edge strength can be improved. However, in contrast to this, in the drilling tool of this type, as described above, especially in the vicinity of the axis O of the tool body 21, the cutting edge 1
Since the load acting on 6 tends to increase, according to the drilling tool of the present embodiment, at the one end portion 16A of the cutting blade 16 where such a high load tends to act, this load is reduced, And because the cutting edge strength can be secured,
It is also possible to obtain the advantage that it is possible to prevent a situation in which the cutting edge 16 is damaged.

Further, in the drilling tool of the present embodiment, the tip 11 arranged on the inner peripheral side of the tool body 21.
Has a square flat plate-shaped chip body 12, and one end portion 16A having a convex shape on all four side ridges of the rake face 13
And a linear other end 16B is formed, and the other end 16b of each cutting edge 16 is formed with a side edge portion where the cutting edge 16 is formed and a cutting edge adjacent to the cutting edge 16. While being positioned at the intersection with the inclined surface 20 formed on the one end 16A side of the blade 16, the tip 23 on the outer peripheral side of the tool body 21 is positioned.
Causes the cutting edge 24 to project toward the tool tip side,
The rotation locus Q of the cutting edge 24 is arranged so as to intersect with the other end 16b of the cutting edge 16 of the tip 11 on the inner peripheral side. Therefore, the convex surface 18 and the inclined surface 20 of the adjacent cutting edges 16 adjacent to the tool outer peripheral side of the other end 16b are
Since the tip 23 is arranged on the tool rear end side with respect to the rotation locus Q of the cutting edge 24 of the tip 23 on the outer peripheral side, the portions of the convex surface 18 and the inclined surface 20 where the cutting edge 16 is not formed are involved in the cutting. Can be avoided. Therefore, in the above-described drilling tool, it is possible to form the largest number of cutting edges 16 on the polygonal rake face 13 of the tip 11 on the inner peripheral side and to use all of these cutting edges 16 for machining. Therefore, the utilization efficiency of the chip 11 can be improved.

By the way, in the chip 11 of the above-described embodiment, as shown in FIG. 5, in the cross section orthogonal to the convex surface 18, that is, in the cross section including the central axis of the cylinder formed by the convex surface 18, the convex surface 18 is formed. The convex surface 18 is formed so that it is parallel to the flat surface portion 19 of the rake face 13. This convex surface 18 is formed like the chip 31 of the second embodiment of the present invention shown in FIGS. 9 to 11. In addition, the convex surface 32 may be formed so as to be gradually depressed toward the seating surface 14 side as it is separated from the cutting edge 16. However, in the embodiment shown in FIGS. 9 to 11 and the third embodiment shown in FIGS. 12 and 13 described later, the first embodiment shown in FIGS.
The same elements as those of the chip 11 of the above embodiment are designated by the same reference numerals and the description thereof will be omitted.

Here, the chip 11 of the first embodiment described above.
In contrast to the convex surface 18 of the second embodiment, which is formed into a cylindrical surface having a central axis parallel to the flat surface portion 19 of the rake surface 13, the convex surface 3 of the tip 21 of the second embodiment is formed.
2 is formed into a cylindrical surface having a central axis extending in a direction oblique to the flat surface portion 19, whereby the convex surface 32 is depressed and inclined as described above, and the cutting edge 16 A positive rake angle β is given to the one end portion 16A. However, it is desirable that this rake angle β is set to 15 ° or less. Further, as the convex surface 32 is formed to be inclined in this way, the convex surface 32 and the flat surface portion 19 of the rake surface 13 are formed.
The intersecting line S formed by and extends in a direction oblique to the linear other end 16B of the cutting edge 16 as shown in FIG. Further, an intersection line B between the convex surface 32 and the inclined surface 20 located on the opposite side of the cutting edge 16 with the convex surface 32 sandwiched therebetween is a flat surface as shown in FIG. 9 in the second embodiment. It is configured to extend parallel to the other end 16B of the cutting blade 16 as viewed. Furthermore, in the second embodiment, the rake face 13
A grooved chip breaker 33 is formed on the flat surface portion 19 along the other end portion 16B of the cutting edge 16.

However, also in the tip 31 of the second embodiment, the convex surface 32 is connected to the one end portion 16A of the cutting edge 16, and the inclined surface 20 is connected to the rear of the convex surface 32. Therefore, similar to the chip 11 of the first embodiment, stress can be applied to the chips in the width direction and the longitudinal direction, and the chips can be reliably divided to achieve efficient processing. Moreover, in the second embodiment, as the convex surface 32 is separated from the cutting edge 16 side, the seating surface 14
Since it is formed so as to be gradually depressed toward the side, that is, is formed so as to descend toward the inclined surface 20 side, the inclination of this inclined surface 20 with respect to the rake surface 13 (flat surface portion 19) is the first. Even if it is the same as the case of the embodiment, the inclination angle θ of the inclined surface 20 with respect to the direction perpendicular to the convex surface 32 can be made small, in other words, the convex surface 32.
It is possible to increase the inclination of the inclined surface 20 with respect to.
On the other hand, when the inclination angle θ of the inclined surface 20 is reduced in this way, the width of the inclined surface 20 also decreases in the first embodiment, but in the second embodiment, the convex surface 32 is inclined. As a result, the crossing line B with the inclined surface 20 causes the cutting edge 16
Since it approaches the side, the width of the inclined surface 20 is rather increased.

Therefore, according to the tip 31 of the second embodiment, the one end portion 16 of the cutting edge 16 is different from that of the first embodiment.
The chips generated by A and scraping the convex surface 32 can be made to ride on the inclined surface 20 that is largely inclined with respect to the convex surface 32, and can be rubbed on the inclined surface 20 for a long time. In addition, since it is possible to reliably apply a stress sufficient to roll it in its longitudinal direction, even if it is used under a work material or machining conditions where chips tend to stretch, it is more efficient. Chip processing can be achieved. Moreover, even if the inclined surface 20 is made long in this way, the width from the cutting edge 16 to the rear end of the inclined surface 20 does not become large, so that the chip size becomes large and the length of the cutting edge 16 becomes short. There is nothing to do. However, also in the second embodiment, the inclination angle θ is 2
It is desirable that the angle be in the range of 5 ° to 65 °.

Further, in addition to this, in the second embodiment, the positive rake angle β is given to the one end portion 16A of the cutting edge 16 by the convex surface 32 being depressed and being inclined downward as described above. Therefore, it is possible to reduce the cutting resistance acting on the one end portion 16A, and in combination with the effect described in the first embodiment, it is possible to more reliably prevent the occurrence of a cutting edge defect or the like. In addition, in the second embodiment, the other end 16B of the cutting blade 16 is provided by the groove-shaped chip breaker 33.
Also in the above, it is possible to promote reliable and prompt division of the generated chips. In the second embodiment, the convex surface 32 is a cylindrical surface that is inclined with respect to the flat surface portion 19 of the rake surface 13 as described above, so that the convex surface 32 is gradually depressed toward the inclined surface 20 side. It was formed into
By forming a conical surface having a central axis parallel or inclined to the plane portion 19, it may be formed so as to be depressed and inclined downward.

Further, the convex surface in the present invention is not limited to one formed by one cylindrical surface or conical surface, and for example, as shown in FIG. 11, one end portion 16A of the cutting edge 16 has a plurality of curvature radii R _1. , R ₂ ..., A plurality of cylindrical surfaces or a conical surface may be a continuous compound convex surface. Furthermore, the end portion 16 of the cutting edge 16 is not limited to such a cylindrical surface or a conical surface and is viewed from the direction facing the flank surface 15.
It is possible to apply all curved surfaces such that the shape of A is a convex curve such as an involute curve, a cycolloid curve, an Archimedes curve, or a parabola.
Further, without being limited to such a curved surface, for example, a plurality of flat surfaces are continuously bent so as to be convex toward the one end 16a side of the cutting edge 16 and are depressed toward the seating surface 14 side to form the convex shape. A surface may be formed, in which case one end 1 of the cutting edge 16
Since the corners are formed in 6A, there is an advantage that the division of the chips in the width direction can be promoted more reliably. Further, such a flat surface may be combined with the various curved surfaces described above. Furthermore, in the first and second embodiments,
The chip body 12 has a square flat plate shape, but this is the chip 41 of the third embodiment shown in FIGS. 12 and 13.
Alternatively, it may be formed in a flat triangular plate shape.

[0033]

As described above, according to the tip of the present invention, the chips produced by the cutting edge are formed by the convex surface formed at one end of the cutting edge and the inclined surface connected to the rear of the convex surface. In addition, sufficient stress can be applied in the width direction and the longitudinal direction to surely divide, and thus efficient chip disposal can be promoted. Further, particularly, according to the drilling tool of the present invention in which the tip is attached to the inner peripheral side of the tool tip, chip clogging or the like is caused even in drilling in which severe conditions are added as compared with general cutting. Without doing so, it is possible to perform stable and highly accurate processing.

[Brief description of drawings]

FIG. 1 is a perspective view of a chip 11 according to a first embodiment of the present invention.

FIG. 2 is a plan view of the chip 11 shown in FIG. 1 viewed from a direction facing a rake face 13;

FIG. 3 is a side view seen from a direction facing a flank surface 15 of the chip 11 shown in FIG.

FIG. 4 is a sectional view taken along line XX in FIG.

5 is a sectional view taken along line YY in FIGS. 2 and 3. FIG.

FIG. 6 is a view showing a tip end portion of a drilling tool according to an embodiment of the present invention in which the tip 11 shown in FIG. 1 is mounted.

FIG. 7 is a diagram showing a rotation trajectory of tips 11, 23 of the drilling tool shown in FIG.

8 is a chip C produced by the drilling tool shown in FIG. 6;
₁ is a diagram illustrating a C _2.

FIG. 9 is a plan view of a chip 31 according to a second embodiment of the present invention.

10 is a ZZ cross-sectional view (corresponding to the YY cross-section in FIG. 3) in FIG. 9;

FIG. 11 is a side view showing a modified example of one end portion 16A of the cutting blade 16 of the chips 11 and 31 of the first and second embodiments.

FIG. 12 is a perspective view showing a chip 41 of a third embodiment of the present invention.

13 is a plan view of the chip 41 shown in FIG.

FIG. 14 is a plan view showing a conventional throw-away tip 1.

15 is a sectional view taken along line CC in FIG.

FIG. 16 is a plan view showing another conventional throw-away tip 5.

17 is a DD cross-sectional view of FIG.

[Explanation of symbols]

11, 31, 41 Chip 12 Chip Body 13 Rake Face (One Polygonal Surface) 14 Seating Surface (Other Polygonal Surface) 15 Flank Surface 16 Cutting Edge 16A One End of Cutting Edge 16 16B Other End of Cutting Edge 16 16a One end of the cutting edge 16 16b The other end of the cutting edge 16 18,32 Convex surface 19 Plane portion 20 Inclined surface 21 Tool body of the drilling tool 23 Tip on the outer peripheral side of the drilling tool 33 Chip breaker θ Convex surface 18, Inclined surface 20 with respect to a direction perpendicular to 32
Tilt angle

Claims (6)

[Claims] 1. A throw-away tip in which one polygonal surface of a polygonal flat plate-shaped tip body is a rake face, and a cutting edge is formed at a side edge portion of the rake face. At one end, the rake face is formed into a convex surface that gradually depresses toward the other polygonal surface side of the tip body as it goes toward the one end side of the cutting edge, and the cutting face of the convex surface is formed. A throw-away tip characterized in that an inclined surface is formed on the side opposite to the blade so as to increase toward the rake surface as it is separated from the convex surface. 2. The inclined surface is convexly recessed toward the other polygonal surface side along the convex surface toward the one end side of the cutting edge. Throw-away tip as described. 3. In a cross section orthogonal to the convex surface, an inclination angle formed by the inclined surface with respect to a direction perpendicular to the convex surface is set in a range of 25 ° to 65 °. The throw-away tip according to claim 1 or 2, which is characterized. 4. The convex surface is formed so as to be gradually depressed toward the other polygonal surface side as it is separated from the cutting edge. The throw-away tip described in either one. 5. An inner peripheral side and an outer peripheral side of a tip portion of the tool main body,
In the throw-away type drilling tool in which each throw-away tip is removably attached, the throw-away tip on the inner peripheral side has one polygonal surface of the polygonal flat plate-shaped tip body as the rake face. A throw-away tip in which a cutting edge is formed at a side edge of a surface, and at one end of the cutting edge, the other polygonal shape of the tip body as the rake face goes toward one end side of the cutting edge. It is formed on a convex surface that gradually depresses toward the surface side, and on the side opposite to the cutting edge of this convex surface, cut toward the one polygonal surface as it is separated from the convex surface. A sloped surface that rises is formed, and the inner throw-away tip projects the cutting edge toward the tool tip side and directs the rake face toward the tool rotation direction and faces the rake face. Indexable drilling tool, characterized in that one end of the cutting edge are arranged so as to substantially located on the central axis of said tool body as viewed from. 6. The throw-away tip on the inner peripheral side comprises:
The chip body is formed in a regular polygonal plate shape, the cutting edge is formed at each side ridge portion of the rake face, and the other end of each cutting edge is a side ridge portion at which the cutting edge is formed. And the indexable tip on the outer peripheral side of the tool body is located at the intersection with the inclined surface formed on the one end side of the cutting edge adjacent to the cutting edge, And a rotational locus of the cutting edge is arranged so as to substantially intersect the other end of the cutting edge protruding toward the tool tip side of the throw-away tip on the inner peripheral side. The throw-away type drilling tool according to Item 5.