JP4081998B2 - Throw-away insert for drilling and throw-away drilling tool - Google Patents

Description

[0001]
BACKGROUND 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, and a throw-away to which this tip is attached. The present invention relates to a type drilling tool (hereinafter referred to as a drilling tool).
[0002]
[Prior art]
Conventionally, this type of drilling tool has a pair of chip discharge grooves formed on the outer periphery of a substantially cylindrical tool body rotated about an axis, and a wall surface facing the front side in the tool rotation direction of these chip discharge grooves A tip mounting seat is formed at the tip of the tip, and for example, a tip having a substantially pentagonal flat plate shape is formed on the tip mounting seat on the front side in the tool rotation direction with one polygonal face as a rake face. At the same time, it is attached so that one side faces the tip side of the tool body as the tip flank, and a cutting edge is formed at the crossing ridge line portion between the rake face and the tip flank.
[0003]
In such a tip, a cylindrical surface that protrudes from the scoop surface toward the other pentagonal surface (sitting surface) on the scoop surface side of the other side surface facing the outer peripheral side of the tool body adjacent to the tip clearance surface. Are formed, and this cylindrical surface serves as a margin portion during drilling.
That is, the margin portion is directed to the outer periphery of the tool body when the insert is attached to the tool body, and presents a part of a cylindrical surface centering on the axis of the tool body. The margin portion slidably contacts the inner wall surface of the machining hole, thereby stabilizing the cutting edge behavior and imparting straightness to the tool body and improving the accuracy of the inner wall surface of the machining hole.
[0004]
[Problems to be solved by the invention]
By the way, in the drilling tool to which the tip is attached as described above, when viewed from the direction facing the rake face of the tip, the margin portion is formed in a straight line shape, and a slight back taper is formed with respect to the margin portion. Given, that is, the margin portion is slightly inclined toward the inner peripheral side of the tool body as it goes toward the base end side of the tool body.
Therefore, if the tip mounting accuracy is slightly deviated due to variations in the processing accuracy of the tip mounting seat or deterioration due to wear, etc., the back taper reverses, that is, the tool as the margin moves toward the tool body base end. There is a possibility that the escape given to the margin portion may be lost by inclining toward the outer peripheral side of the main body. As a result, the cutting resistance received by the drilling process becomes very large, the machining efficiency is deteriorated, the chatter vibration cannot be stabilized and the chatter vibration is generated, and the inner wall accuracy of the machining hole is increased. There is a risk of worsening.
[0005]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a chip and a drilling tool that can reliably ensure escape provided to the margin portion even if the chip mounting accuracy deteriorates.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve such an object, the chip of the present invention is configured such that one polygonal surface of a chip body having a substantially polygonal flat plate shape is a rake surface and one side surface. Is a flank, a cutting edge is formed at the intersecting ridge line portion between the rake face and the flank face, and the other flank face adjacent to the flank face is directed from the rake face to the other polygonal face. A tip that forms a marginal part in the drilling process, and when the tip is attached to a drilling tool, when viewed from the direction facing the rake face, The margin portion forms an R with a point on the straight line passing through a point that is the same as or closer to the tip side of the margin portion in the axial direction of the drilling tool and is perpendicular to the axis line as the center of curvature. It is characterized by being formed.
Further, the drilling tool of the present invention has a pair of chip discharge grooves formed on the outer periphery of the tool body rotated around the axis, and is formed at the tip of the wall surface facing the front side in the tool rotation direction of these chip discharge grooves. The tip of the present invention is placed on the tip mounting seat, with the rake face facing the front side in the tool rotation direction, the flank face facing the tool body tip side, and the margin portion facing the tool body outer peripheral side. It is attached so that it may form a part of cylindrical surface centering on an axis.
With such a configuration, the margin portion of the tip becomes R such that the tip gradually inclines from the distal end side to the proximal end side of the tool body toward the inner peripheral side of the tool body. Is provided with a relief and a back taper. By providing the relief by the R of the margin portion, even if the chip mounting accuracy is somewhat deteriorated, the relief corresponding to the back taper can be reliably obtained by this R.
Furthermore, as seen from the direction facing the rake face, the inner wall surface of the machining hole is smoothly rubbed by a curved margin that protrudes toward the outer periphery of the tool body, so that the accuracy of the inner wall surface can be improved. it can.
[0007]
Further, the radius of curvature of R formed by the margin portion is set in a range of 100 to 1000 mm.
Here, if the radius of curvature of R formed by the margin portion is too small, the relief given to the margin portion becomes extremely large, and the cutting edge behavior cannot be stabilized, whereas the curvature of R formed by the margin portion is not achieved. If the radius is too large, the relief given to the margin portion becomes very small, and depending on the chip mounting accuracy, the back taper may be reversed. Therefore, in the present invention, the radius of curvature of R formed by the margin portion is present. Is set in the range of 100 to 1000 mm, the clearance given to the margin portion can be made appropriate.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 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, and FIG. 3 is an enlarged view of a main part in FIG.
[0009]
In the present embodiment, the tool body 1 of the drilling tool has a substantially cylindrical shape that is rotated around the axis O, and the outer periphery of the tip is open to the tip surface 1A of the tool body 1 and around the axis O. In addition, a pair of chip discharge grooves 2, 2 that are twisted toward the rear side in the tool rotation direction T and toward the base end side are formed symmetrically with respect to the axis O.
Further, in the inside of the tool body 1, a portion of the shank 1C extends from the base end surface 1B along the axis O toward the front end side, branches near the front end, and opens to the front end surface 1A. The supply path 3 is formed. Further, tip mounting seats 4, 4 are formed at the tips of the wall surfaces 2A, 2A facing the front side in the tool rotation direction T of the chip discharge grooves 2, 2, respectively. A chip as shown in 1 is attached.
[0010]
In this chip, the chip body 10 is made of a hard material such as a cemented carbide and has a substantially pentagonal flat plate shape. One of the pentagonal surfaces is a rake surface 11 and the other pentagonal surface is a seating surface 12. It is said that. Further, one side surface of the chip body 10 is a flank 13, and a cutting edge 14 is formed at a crossing ridge line portion between the flank 13 and the rake face 11. Here, the tip of the present 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 honed.
Furthermore, an attachment hole 15 for attaching the chip body 10 to a drilling tool is formed in a substantially central portion of the rake face 11 so as to penetrate to the seating surface 12 along the thickness direction of the chip body 10.
[0011]
The other side surface 16 of the chip body 11 adjacent to one side surface forming the flank 13 is a flank surface 13 at a corner C1 on the one end 14A side of the cutting blade 14 when viewed from the direction facing the rake surface 11. And are arranged so as to intersect at an acute angle.
Further, on the rake face 11 of the corner C1 where the flank 13 and the side face 16 intersect, a cylindrical surface 17 is formed which is curved toward the seating surface 12 while being curved toward the tip side of the corner C1. ing. On the cylindrical surface 17, a notch 17A is formed in a portion that is spaced from the tip of the corner C1 and is located on the side 16 side.
Therefore, the cylindrical surface 17 formed on the rake face 11 intersects the flank surface 13 to form a portion on the one end 14A side (side surface 16 side) of the cutting blade 14, thereby a portion on the one end 14A side of the cutting blade 14. Is formed to be curved in a convex curve toward the seating surface 12 as it goes toward the one end 14A.
[0012]
Further, another side surface 18 of the chip body 11 adjacent to one side surface forming the flank 13 is a corner C2 on the other end 14B side of the cutting blade 14 when viewed from the direction facing the rake surface 11. It is arranged so as to intersect with the flank 13 at an obtuse angle, and is inclined so as to approach the side surface 16 as it is separated from the other end 14B of the cutting blade 14.
[0013]
Further, a cylindrical surface that protrudes from the rake face 11 toward the seating face 12 is formed on the side of the rake face 11 of the side face 18 to form a margin portion 19. In addition, the part except the margin part 19 in the side surface 18 is formed so that it may incline inside as it goes to the seating surface 12 side.
The margin portion 19 has a radius of curvature equal to the radius of curvature of the machining hole drilled by the drilling tool, and forms a part of a cylindrical surface centering on the axis O of the tool body 1 as will be 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 drilling.
In the present embodiment, the margin portion 19 is formed in an R shape that protrudes outward from the chip body 10 when viewed from the direction facing the rake face 11. This will be described later.
[0014]
In addition, an inclined surface 20 is formed on the rake face 11 connected to the other end 14B side of the cutting edge 14 so as to be inclined toward the seating face 12 as the distance from the cutting edge 14 increases. On the opposite side of the inclined surface 20 from the other end 14B side of the cutting edge 14, a breaker wall surface 21 is formed which is smoothly connected to the inclined surface 20 and stands up while drawing a concave curved surface as the distance from the cutting edge 14 increases. Has been.
[0015]
On the other hand, the tip mounting seat 4 to which the above-described tip is attached is erected from a bottom surface formed so as to be recessed one step from the wall surface 2A facing the front side in the tool rotation direction T of the chip discharge groove 2, A wall surface 4A facing the outer peripheral side of the tool body and a wall surface 4B facing the tip side of the tool body are formed, and screw holes (not shown) are formed on the bottom surface.
[0016]
The bottom surface of the chip mounting seat 4 is located on the base end side of the tool body so that the rake face 11 forms a positive axial rake angle with respect to the axis O of the tool body 1 when the above chip is mounted. As it goes to, it is formed so as to be inclined toward the rear side in the tool rotation direction T.
Further, when viewed from the direction facing the bottom surface of the chip mounting seat 4, the wall surface 4A facing the tool body outer peripheral side of the chip mounting seat 4 is directed toward the tool body outer peripheral side as it goes toward the tool body base end side. Further, the wall surface 4B facing the tool body tip side of the tip mounting seat 4 is formed so as to go to the tool body tip side as it goes to the tool body outer peripheral side. Note that a corner portion where the wall surfaces 4A and 4B intersect with each other is formed with a thin portion for avoiding interference with the corner portion of the chip.
[0017]
The above-mentioned chip is brought into close contact with the bottom surface of the chip mounting seat 4 on the chip mounting seat 4 formed in this manner, and the wall surface 4A of the chip mounting seat with the side surface 16 facing the inner peripheral side of the tool body. Further, the side surface 22 adjacent to the side surface 18 on the side opposite to the flank 13 is brought into contact with the wall surface 4B of the chip mounting seat 4 and attached. In this state, the tip body 10 has the rake face 11 facing the front side in the tool rotation direction T, the flank face 13 facing the tip side of the tool body 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.
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 on the bottom surface of the chip mounting seat 4. However, the two chips attached to the chip mounting seats 4 and 4 have the same shape and the same size, and are mounted symmetrically about the axis O.
[0018]
The cutting blades 14 and 14 of the chips attached in this way are projected from the tip surface 1A of the tool body 1 to the tool body tip side, and their one ends 14A and 14A are aligned with the tool rotation center at the tip of the tool body 1. And arranged so as to incline toward the base end side of the tool body as it goes from the one end 14A to 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 main body 1 toward the outer peripheral side of the tool main body, and is arranged so as to form a part of a cylindrical surface centering on the axis O.
[0019]
Thus, when the tip body 10 is viewed from the direction facing the rake face 11 in a state where the tip according to the present embodiment is attached to the drilling tool, the margin portion 19 has a margin in the axis O direction. The point 19 is formed at an R with the point X existing at the same position as the point (the other end 14 </ b> B of the cutting edge 14) located at the most distal end side in the portion 19.
That is, the margin portion 19 is a point on a straight line that passes through a point (the other end 14B of the cutting blade 14) located at the most distal end side in the margin portion 19 when viewed from the direction facing the rake face 11 and is orthogonal to the axis O. It is formed in R with X as the center of curvature.
[0020]
The radius of curvature a of the margin portion 19, that is, the distance from the curvature center X to the margin portion 19 is set in a range of 100 mm ≦ a ≦ 1000 mm. In this embodiment, for example, a = 472 mm.
Here, the outer diameter D of the cutting blade 14 of the drilling tool in the present embodiment, that is, the distance between the other ends 14B and 14B of the cutting tips 14 and 14 of the two chips attached symmetrically with respect to the axis O is, for example, The radius of curvature a of R formed by the margin 19 is set in a range of 5D ≦ a ≦ 50D with respect to the outer diameter D of the cutting edge 14.
[0021]
According to this embodiment, the margin portion 19 of the tip is gradually inclined toward the inner peripheral side of the tool body from the distal end side to the proximal end side of the tool body 1 when viewed from the direction facing the rake face 11. R is automatically given to the margin 19 and a back taper is provided.
As described above, since the margin portion 19 escapes due to the R formed by the margin portion 19, even if the chip mounting accuracy is somewhat deteriorated and the position accuracy of the margin portion 19 is distorted, By R, it is possible to reliably give the margin portion 19 a clearance corresponding to the back taper. Therefore, the cutting resistance received by the drilling process does not increase, and the chatter vibration is not generated by stabilizing the cutting edge behavior while maintaining good machining efficiency.
Moreover, during the drilling process, the marginal portion 19 formed in an R shape is slidably contacted with the inner wall surface of the processing hole by the smooth curved surface, and rubs generated on the inner wall surface are rubbed. It is also possible to improve the inner wall surface accuracy.
[0022]
Here, when the radius of curvature a of the R formed by the margin portion 19 is smaller than 100 mm, the margin portion 19 is extremely in the tool body as viewed from the direction facing the rake face 11 toward the base end side of the tool body. As the distance approaches the circumferential side, the relief given to the margin 19 becomes larger than necessary, and the effect of forming the margin 19 such as stabilization of the cutting edge behavior cannot be obtained.
On the other hand, when the radius of curvature a of R formed by the margin portion 19 is larger than 1000 mm, the margin portion 19 is almost in a straight line when viewed from the direction facing the rake face 11, and the clearance given to the margin portion 19 is very large. Since it becomes smaller, the back taper may be reversed depending on the mounting accuracy of the chip.
Therefore, in this embodiment, by setting the radius of curvature “a” of the R formed by the margin portion 19 in the range of 100 to 1000 mm, the relief given to the margin portion 19 can be made appropriate. In order to make the above-described effect more reliable, it is preferable that the radius of curvature a of R formed by the margin portion 19 is set in a range of 300 to 700 mm.
[0023]
In the present embodiment, the curvature center X of R formed by the margin portion 19 is set at the same position as the point located on the most distal end side of the margin portion 19 in the axis O direction, but is not limited thereto. Instead, the radius of curvature of R of the margin portion 19 may be set with the point located on the tip side in the axis O direction from the center of curvature X as the center of curvature.
For example, as shown in FIG. 3, even if the radius of curvature a ′ of R of the margin portion 19 is set with the point of movement 0.5 mm further from the center of curvature X toward the tip side in the axis O direction as the center of curvature X ′. Good. In this case, in this embodiment, a ′ = 563 mm.
[0024]
【The invention's effect】
According to the present invention, as viewed from the direction facing the rake face, in the axial direction of the drilling tool, on a straight line that passes through a point that is the same as or closer to the front end of the margin portion than the front end of the margin portion . by giving a relief to form a margin portion so as to form a R in which the point with the center of curvature, even if mounting accuracy of the chip was slightly worse, the escape of an amount corresponding to a back taper by the R You can definitely get it.
Furthermore, since the inner wall surface of the machining hole is smoothly scraped by the margin portion that forms a curved surface that protrudes toward the outer peripheral side of the tool body when viewed from the direction facing the rake surface, the accuracy of the inner wall surface can be improved. .
[Brief description of the 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 chip according to the present embodiment is attached.
FIG. 3 is an enlarged view of a main part in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tool main body 2 Chip discharge groove 4 Chip mounting seat 10 Chip main body 11 Rake face 13 Relief face 14 Cutting edge 14A Cutting edge one end 14B Cutting edge other end 18 Side face 19 Margin

Claims (3)

One polygonal surface of the chip body having a substantially polygonal flat plate shape is a rake face, and one side face is a flank face. In addition, a cylindrical surface that protrudes from the rake surface toward the other polygonal surface is formed on the other side surface adjacent to the flank surface to form a margin portion in the drilling process. A throw-away chip,
When the throw-away tip for drilling is attached to a drilling tool, the margin portion is positioned in the axial direction of the drilling tool as viewed from the direction facing the rake face and the tip of the margin portion. A throw-away tip for drilling, which is formed so as to have an R having a point on a straight line that passes through the same point or a point positioned on the tip side more than this and is orthogonal to the axis as a center of curvature. In the throw-away tip for drilling according to claim 1,
A throw-away tip for boring, wherein a radius of curvature of R formed by the margin portion is set in a range of 100 to 1000 mm. A pair of chip discharge grooves are formed on the outer periphery of the tool body rotated about the axis, and the chip mounting seat formed at the tip of the wall surface facing the front side of the tool rotation direction of these chip discharge grooves is claimed in claim 1 or claim 2. The throw-away tip for drilling according to Item 2, wherein the rake face faces the front side in the tool rotation direction, the flank face faces the tip end side of the tool body, and the margin portion faces the outer periphery side of the tool body. A throw-away drilling tool, which is attached so as to face a part of a cylindrical surface centering on the axis.

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