JP2003019611A - Throwaway tip for drilling, and throwaway type drilling tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the behavior of a cutting edge without increasing the cutting resistance. SOLUTION: In a condition that a tip is fitted to a body 1 of a drilling tool, the width T of a margin part 19 is formed so as to be increased at a predetermined rate from the base end side in the axial direction O to the tip side. In the margin part 19, the width T1 at the most distal side in the axial direction O is set in a range of 0.08D<=T<=0.20D with respect to the outside diameter D of the cutting edge 14 of the drilling tool, and the width T2 at the most proximal side of the base end in the axial direction O is set in a range of 0.03D<=T<=0.08D with respect to the outside diameter D of the cutting edge 14 of the drilling tool. The length L of the margin part 19 in the axial direction O is set in a range of 0.13D<=L<=0.25D with respect to the outside diameter D of the cutting edge 14 of the drilling tool.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip for drilling (hereinafter referred to as a tip) suitable for being attached to a throw-away type drilling tool or the like and used for drilling. The present invention relates to a throw-away type drilling tool (hereinafter referred to as a drilling tool) to which a tip is attached.

[0002]

2. Description of the Related Art Conventionally, in this type of drilling tool, a pair of chip discharge grooves are formed on the outer periphery of a substantially cylindrical tool body which is rotated around an axis, and these chip discharge grooves are formed in the tool rotation direction. A tip mounting seat is formed at the tip of the wall surface facing the front side.In this tip mounting seat, for example, a substantially pentagonal flat plate-shaped tip is used to rotate the tool with one of its polygonal faces as the rake face. It is attached so that it faces toward the front side in the direction and one side faces toward the tip side of the tool body as a tip flank, and a cutting edge is formed at the ridge line portion where these rake face and tip flank intersect.

In such a tip, the rake face side of the other side face facing the outer peripheral side of the tool body adjacent to the tip flank face is curved from the rake face toward the other pentagonal face (seating face). A cylindrical surface is formed, and this cylindrical surface serves as a margin portion during drilling. That is, the margin portion faces the outer peripheral side of the tool body when the tip is attached to the tool body, and presents a part of the cylindrical surface centered on the axis of the tool body. The sliding contact of the margin portion with the inner wall surface of the machined hole serves to stabilize the behavior of the cutting edge to impart straightness to the tool body and to improve the accuracy of the inner wall surface of the machined hole.

[0004]

By the way, in the drilling tool to which the tip is attached as described above, the width of the margin portion of the tip, that is, the direction orthogonal to the axis when viewed from the direction facing the margin portion. The length of the margin portion is formed to have the same width from the base end side to the tip end side in the axial direction. Therefore, the area of the tip side of the margin part located near the cutting edge is not sufficiently secured, and when biting into the workpiece where the stability of the cutting edge behavior is more required, the tip side of this margin part Due to lack of area of the part,
Since the straightness of the tool body cannot be obtained, the hole position accuracy of the machined hole to be drilled may be deteriorated. Here, when the width of the margin portion is formed to be larger than usual, the area of the base end side portion of the margin portion becomes too large accordingly, and when the base end side portion slides on the inner wall surface of the processed hole, It causes an increase in cutting resistance.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a tip and a drilling tool capable of stabilizing the behavior of the cutting edge without increasing the cutting resistance.

[0006]

[Means for Solving the Problems] By solving the above problems,
In order to achieve such an object, the chip of the present invention is
While one polygonal surface of the chip body forming a substantially polygonal flat plate shape is a rake face, one side surface is a flank face, a cutting edge is formed at the ridge line portion intersecting these rake face and flank face, And, a chip that forms a margin portion at the time of punching by forming a cylindrical surface that is convexly curved from the rake surface toward the other polygonal surface on the other one side surface adjacent to the flank surface, When the tip is attached to a drilling tool, the width of the margin portion is formed so as to gradually increase from the base end side to the tip end side in the axial direction of the drilling tool. And Further, in the drilling tool of the present invention, a pair of chip discharge grooves are formed on the outer periphery of the tool body rotated about the axis, and the chip discharge grooves are formed at the tip of the wall surface facing the front side in the tool rotation direction of the chip discharge grooves. In the tip mounting seat, the tip of the present invention, the rake face faces the front side in the tool rotation direction, the flank faces the tool body tip side, and the margin portion faces the tool body outer peripheral side, It is characterized in that it is attached so as to form a part of a cylindrical surface around the axis. With such a configuration, the area of the tip end side portion in the axial direction of the margin portion is secured to be large, so that the tip end side portion of the margin portion close to the cutting edge slides in contact with the inner wall surface of the machining hole with a large area, It is possible to stabilize the behavior, especially when biting on the work piece.
It becomes possible to secure more stable cutting edge behavior. Moreover, since the area of the base end side portion of the margin portion is set smaller than that of the tip end side portion, the cutting resistance is not increased.

Further, the width T of the margin portion is set in the range of 0.08D≤T≤0.20D with respect to the outer diameter D of the cutting edge of the drilling tool at the most tip end side in the axial direction. Further, at the most proximal end side in the axial direction, with respect to the outer diameter D of the cutting edge of the drilling tool, a range of 0.03D ≦ T ≦ 0.08D is set. Here, if the width of the margin portion on the most distal side in the axial direction is too small, the area of the margin portion necessary to stabilize the cutting edge behavior cannot be secured, and conversely, the width of the margin portion is too large. However, there is a risk that the cutting resistance will increase. On the other hand, if the width of the margin portion on the most proximal side in the axial direction is too small, the behavior of the cutting edge cannot be similarly stabilized. Conversely, if the width of the margin portion is too large, the cutting resistance is also the same. Will increase. Therefore, in the present invention, the width of the margin portion is set within the appropriate range as described above.

Further, the length L of the margin portion in the axial direction is 0..L with respect to the outer diameter D of the cutting edge of the drilling tool.
It is characterized in that it is set in a range of 13D ≦ L ≦ 0.25D. Here, if the length of the margin portion in the axial direction is too small, the behavior of the cutting edge cannot be stabilized, and conversely, if the length of the margin portion is too large, the cutting resistance is increased. Therefore, in the present invention, the length of the margin portion is set to an appropriate range as described above.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a perspective view of a chip according to the present embodiment, FIG. 2 is a side view of a drilling tool to which the chip is attached, FIG. 3 (a) is an enlarged view of a main part of FIG. 2, and FIG. It is an A direction arrow line view.

In this embodiment, the tool body 1 of the drilling tool has a substantially columnar shape which is rotated around the axis O, and the outer periphery of the tip end portion is opened to the tip end surface 1A of the tool body 1. A pair of chip discharge grooves 2 and 2 which are twisted rearward in the tool rotation direction T around the axis O and are directed toward the base end side are formed symmetrically with respect to the axis O. Further, inside the tool body 1, a lubricant coolant or the like which extends from the base end face 1B along the axis O toward the tip side of the shank 1C and branches near the tip end to open to the tip face 1A, etc. Supply path 3
Are formed. Further, chip mounting seats 4 and 4 are formed at the tips of the wall surfaces 2A and 2A facing the front side in the tool rotation direction T of the chip discharging grooves 2 and 2, respectively. A chip as shown in 1 is attached.

In this chip, the chip body 10 is made of a hard material such as cemented carbide and has a substantially flat pentagonal plate shape, and one pentagonal surface is a rake surface 11 and the other pentagonal surface is It is the seating surface 12. Further, one side surface of the chip body 10 is a flank 13, and a cutting edge 14 is formed at a ridge line portion where the flank 13 and the rake face 11 intersect with each other. Here, the tip of this embodiment is a positive type in which the rake face 11 and the flank face 13 intersect at an acute angle via the cutting edge 14, and the cutting edge 14 is subjected to honing. Further, a mounting hole 15 for mounting the chip body 10 on a drilling tool is provided at a substantially central portion of the rake face 11 along the thickness direction of the chip body 10.
It is formed so as to penetrate up to 2.

The other side surface 16 of the chip body 11 adjacent to the side surface forming the flank 13 is a corner C1 on the one end 14A side of the cutting edge 14 when viewed from the direction facing the rake surface 11.
In, it is arranged so as to intersect with the flank 13 at an acute angle. Further, on the rake surface 11 of the corner C1 where the flank 13 and the side surface 16 intersect, a cylindrical surface 17 is formed which is convexly curved toward the seating surface 12 side toward the tip side of the corner C1. ing. In addition, on this cylindrical surface 17, a cutout portion 17A is formed in a portion located away from the tip of the corner portion C1 and located on the side surface 16 side. Therefore, the cylindrical surface 17 formed on the rake face 11 is
By forming a portion on the one end 14A side (side surface 16 side) of the cutting blade 14 by intersecting with 3, the portion of the cutting blade 14 on the one end 14A side is seated according to the one end 14A side.
It will be formed by curving in a convex curve shape toward the 2 side.

The other side surface 18 of the chip body 11 adjacent to the side surface forming the flank 13 is the other end 14B of the cutting edge 14 when viewed from the direction facing the rake surface 11.
The corner C2 on the side is arranged so as to intersect the flank 13 at an obtuse angle, and is inclined so as to approach the side surface 16 side as the distance from the other end 14B of the cutting edge 14 increases.

Further, on the side of the rake face 11 of the side face 18, a cylindrical surface which is convexly curved from the rake face 11 toward the seating face 12 is formed to form a margin portion 19. In addition, side surface 1
8 except the margin portion 19 is the seating surface 12
It is formed so as to incline inward as it goes to the side. The margin portion 19 has a radius of curvature equal to the radius of curvature of the machined hole drilled by the drilling tool, and forms a part of a cylindrical surface centered on the axis O of the tool body 1 as described later. It is attached to the tool body 1 and comes into sliding contact with the inner wall surface of the processed hole during the drilling process. Then, in the present embodiment, the width T of the margin portion 19 is
The cutting edge 14 is formed so as to gradually increase toward the other end 14B side. Note that this will be described later.

Further, on the rake face 11 which is continuous with the portion of the cutting edge 14 on the other end 14B side, the inclined surface 2 which is inclined toward the seating surface 12 side as it is separated from the cutting edge 14.
0 is formed, and a concave curved surface is drawn on the side opposite to the other end 14B side of the cutting edge 14 across the inclined surface 20 so as to smoothly connect to the inclined surface 20 and separate from the cutting edge 14. A breaker wall surface 21 that stands upright is formed.

On the other hand, the tip mounting seat 4 to which the above-mentioned tip is mounted is a bottom surface 4A formed so as to be recessed from the wall surface 2A facing the front side of the chip discharge groove 2 in the tool rotation direction T, and this bottom surface 4A. And a wall surface 4B facing the outer peripheral side of the tool body and a wall surface 4C facing the tip side of the tool body, and a screw hole (not shown) is formed on the bottom surface 4A.

The bottom surface 4A of the tip mounting seat 4
Is the rake face 11 when the above tip is attached.
Is formed so as to form a positive rake angle in the axial direction with respect to the axis O of the tool body 1, and is inclined toward the rear side in the tool rotation direction T according to the base end side of the tool body. Further, when viewed from the direction facing the bottom surface 4A of the tip mounting seat 4, the wall surface 4B of the tip mounting seat 4 which faces the outer peripheral side of the tool main body is directed toward the outer peripheral side of the tool main body toward the base end side of the tool main body. Further, the wall surface 4C of the tip mounting seat 4 which faces the tip side of the tool body is formed so as to face the tip side of the tool body along the outer peripheral side of the tool body. At the corners where these wall surfaces 4B and 4C intersect, a recessed portion is formed to avoid interference with the corners of the chip.

On the chip mounting seat 4 thus formed,
The above-mentioned tip makes its seating surface 12 closely contact with the bottom surface 4A of the tip mounting seat 4, and makes the side surface 16 contact the wall surface 4B of the tip mounting seat toward the inner peripheral side of the tool body. Side 22 adjacent to side 18 on the opposite side
Is brought into contact with the wall surface 4C of the chip mounting seat 4 to be mounted. In this state, in the chip body 10, the rake face 11 faces the front side in the tool rotation direction T, the flank face 13 faces the tool body tip side as the tip flank face, and the margin portion 19 is formed. The side surface 18 faces the outer peripheral side of the tool body. Then, the chip is fixed to the tool body 1 by screwing the clamp screw inserted into the mounting hole 15 into the screw hole formed in the bottom surface 4A of the chip mounting seat 4. However, the two chips mounted on the chip mounting seats 4 and 4 have the same shape and size, and are mounted symmetrically with respect to the axis O.

The cutting edge 1 of the tip thus mounted
4, 14 are made to project from the tip surface 1A of the tool body 1 toward the tip side of the tool body, and one ends 14A, 14A thereof are butted so as to coincide with the tool rotation center of the tip of the tool body 1 and They are arranged so as to incline toward the tool body proximal end side from 14A toward the other end 14B. Further, the margin portion 19 formed on the side surface 18 slightly protrudes from the outer peripheral surface of the tool body 1 toward the outer peripheral side of the tool body, and is arranged so as to form a part of a cylindrical surface centered on the axis O.

As described above, when the tip of this embodiment is attached to the drilling tool, the width T of the margin portion 19 of the tip gradually increases toward the other end 14B of the cutting edge 14. Therefore, when the chip body 10 is viewed from the direction facing the margin portion 19, the width T of the margin portion 19 is as shown in FIG.
(The length of the margin portion 19 in the direction orthogonal to the axis O)
Is formed so as to increase from the base end side in the direction of the axis O toward the tip end side at a constant rate. Therefore, the margin portion 19 has the tip side portion 1 in the direction of the axis O thereof.
The area of 9A is secured large, and the area of the base end side portion 19B in the direction of the axis O is smaller than that of the tip end side portion 19A.

In the margin portion 19, the width T1 at the most tip end side in the direction of the axis O is the outer diameter D of the cutting edge 14 of the drilling tool (2 attached symmetrically with respect to the axis O).
The distance T2 between the other ends 14B, 14B of the cutting edges 14, 14 of one chip is set in the range of 0.08D ≦ T ≦ 0.20D, and the width T2 at the most proximal end side in the axis O direction is set. , With respect to the outer diameter D of the cutting edge 14 of the drilling tool, 0.03D ≦ T
It is set in the range of ≦ 0.08D. The outer diameter D of the cutting edge 14 of the drilling tool in this embodiment is, for example, 2
It is set to 0 mm, and the margin width of the tip in the conventional drilling tool is usually set to 0.06D.

Furthermore, the length L of the margin portion 19 in the direction of the axis O, that is, the maximum distance of the portion where the margin portion 19 extends in the direction of the axis O, as shown in FIG.
For the outer diameter D of the cutting edge 14 of the drilling tool, 0.13D ≦
It is set within the range of L ≦ 0.25D.

According to this embodiment, since the area of the tip side portion 19A of the margin portion 19 is secured larger than that of the conventional one, the tip side portion 19A of the margin portion 19 near the cutting edge 14 is machined. By slidingly contacting the inner wall surface of the hole over a large area, the behavior of the cutting edge can be stabilized and the tool body 1 can be provided with straightness. In particular, it is possible to exert an effect when biting into a work that requires more stable cutting edge behavior, and it is possible to maintain good hole position accuracy of a machined hole to be drilled. Moreover, by setting the area of the base end side portion 19B of the margin portion 19 smaller than that of the tip end side portion 19A and smaller than the conventional one, it is possible to reduce the cutting resistance. Efficiency does not deteriorate.

If the width T1 of the margin portion 19 on the most tip side in the direction of the axis O is smaller than 0.08D, the area of the tip side portion 19A cannot be sufficiently secured and the cutting edge behavior is stabilized. On the contrary, even if the width T1 is too large, the area of the front end side portion 19A becomes larger than necessary, which causes an increase in cutting resistance. Similarly, if the width T2 of the margin portion 19 on the most proximal end side in the axis O direction is smaller than 0.03D, the area of the proximal end portion 19B cannot be sufficiently secured, and stable cutting edge behavior is obtained. On the contrary, even if the width T2 is too large, the area of the base end side portion 19B becomes larger than necessary and the cutting resistance increases.

Further, even if the length L of the margin portion 19 becomes smaller than 0.13D, the margin portion 1
Since the area of 9 is insufficient and the behavior of the cutting edge cannot be stabilized, and conversely, even if the length L of the margin portion 19 is larger than 0.25D, the cutting resistance is increased. I will end up.

Therefore, in this embodiment, as described above, the widths T1 and T2 of the margin portion 19 are set to 0.08D≤T.
1 ≦ 0.20D, 0.03D ≦ T2 ≦ 0.08D, and the length L of the margin part is 0.13D ≦
By setting the range of L ≦ 0.25D, it is possible to more reliably stabilize the cutting edge behavior and suppress the cutting resistance.

[0027]

According to the present invention, a large area of the margin portion at the tip end portion in the axial direction is secured, and the tip end portion of the margin portion near the cutting edge slides in contact with the inner wall surface of the machined hole with a large area. It is possible to stabilize the behavior of the cutting edge, and in particular, it is possible to exert an excellent effect when biting into a work. Moreover, the area of the base end side portion of the margin portion can be set smaller than that of the tip end side portion, and the cutting resistance can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of a chip according to an embodiment.

FIG. 2 is a side view of a drilling tool to which a tip according to the present embodiment is attached.

3 (a) is an enlarged view of a main part in FIG. 2, (b).
[Fig. 4] is a view from the direction of the arrow A in (a).

[Explanation of symbols]

1 Tool body 2 Chip discharge groove 4 Tip mounting seat 10 chip body 11 rake face 13 flank 14 cutting edge 14A One end of cutting edge 14B The other end of the cutting edge 18 sides 19 Margin section 19A Tip side part 19B Base end side part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuhiko Kawade             1528, Nakashinden, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture             Address Mitsubishi Materials Corporation Gifu Factory             Within F-term (reference) 3C037 BB00

Claims (4)

[Claims] 1. A chip body having a substantially polygonal flat plate shape, wherein one polygonal surface of the chip body is a rake face and one side surface is a flank face, and a ridge line crossing between the rake face and the flank face is formed. A blade is formed, and on the other side surface adjacent to the flank, a cylindrical surface that is convexly curved from the rake surface to the other polygonal surface is formed, and a margin portion at the time of drilling is formed. A throwaway insert for drilling, wherein when the drilling insert for a drilling process is attached to a drilling tool, the width of the margin portion is from the base end side in the axial direction of the drilling tool. A throw-away tip for drilling, which is formed so that it gradually increases toward the tip side. 2. The throw-away tip for drilling according to claim 1, wherein the width T of the margin portion is at the most distal end side in the axial direction with respect to the outer diameter D of the cutting edge of the drilling tool. 0.08
It is set in the range of D ≦ T ≦ 0.20D, and in the range of 0.03D ≦ T ≦ 0.08D with respect to the outer diameter D of the cutting edge of the drilling tool at the most proximal end side in the axial direction. Throw-away tip for drilling, characterized by being set. 3. The throw-away insert for drilling according to claim 1 or 2, wherein the axial length L of the margin portion is relative to the outer diameter D of the cutting edge of the drilling tool. 0.13D ≦ L ≦ 0.2
A throwaway insert for drilling, characterized by being set in the range of 5D. 4. A pair of chip discharge grooves are formed on the outer circumference of a tool body rotated about an axis, and a chip mounting seat formed at the tip of a wall surface of these chip discharge grooves facing the front side in the tool rotation direction, The throw-away tip for drilling according to any one of claims 1 to 3, wherein the rake face faces the front side in the tool rotation direction, and the flank faces the tool body tip side, and A throw-away type drilling tool, characterized in that the margin part is attached so as to face the outer peripheral side of the tool body and forms a part of a cylindrical surface centered on the axis.