JP4688378B2 - Throw-away tip for drill - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drill throw-away tip for drilling.
[0002]
[Prior art]
As a drill used for drilling, in addition to a normal solid type drill that is integrally formed as a whole, a cutting blade is formed on a separate throw-away tip from the drill body, and this is attached to the tip of the holder. There is a so-called throw-away drill that can be detachably attached with a screw or the like.
For this throw-away drill, it is particularly important to improve the chip discharge property in order to ensure the processing reliability.
[0003]
The indexable drill, generally using two cutting edges of the outer cutter and inner cutter, an outer region of each hole bottom, and share the cutting of the inner region.
[0004]
And in order to improve chip discharge | emission property, what is especially important is chip | tip discharge | emission property by the side of the outer blade which becomes easy to extend at high speed.
[0005]
As a technique for improving the chip disposability on the outer blade side, a technique for reducing the size of a single chip and improving the discharge performance by dividing the chip has been studied or implemented so far. One of them is to divide chips by forming stepped parts with corners R (arc blades) at both ends by providing steps in the cutting direction at the outer end of the outer blade to divide the chips. Technology.
[0006]
Secondly, the step of the tip thickness direction is provided in the outer cutter, there is a technique for separating the chips.
[0007]
In this technique, the cutting edge corner portion in the stepped portion is a substantially sharp corner, and the breaker wall of the breaker groove on the chip discharge side of the stepped portion is in the chip thickness direction and the cutting direction of the outer blade. It was a continuous wall with no steps.
[0008]
[Problems to be solved by the invention]
However, in the case of the above-described conventional technique in which the outer blade is provided with a step in the cutting direction, there is no step in the chip thickness direction in the outer blade and the breaker groove, and the breaker groove is continuously formed. The structure was such that the chips cut off at the portions were easy to contact. Therefore, especially when the chip temperature is high, during dry processing or high-feed processing, when the cut chips come into contact with each other in the breaker groove, the chips are hot, so they are recombined and the cutting effect is high. There was a drawback of disappearing.
[0009]
On the other hand, in the case of the latter prior art in which the outer blade is provided with a step in the chip thickness direction, the breaker wall of the breaker groove on the chip discharge side of the step portion is continuous without any step in the chip thickness direction or the cutting direction of the outer blade. Since this was a typical wall, the chip was easy to contact with the chip at the breaker wall. Therefore, as in the case of the former prior art, there has been a drawback that the divided chips are recombined during dry processing or high feed processing, and the effect of the division is lost.
[0010]
Further, in the case of the latter prior art, the cutting edge corner portion (projecting corner portion) in the stepped portion is a substantially sharp corner, so that this portion is easily lost and cannot be used for high-load machining. was there.
[0011]
Therefore, the present invention solves these problems, that is, when the chip temperature is high, during dry processing or high feed processing, the divided chips come into contact with each other in the breaker groove and the cutting effect is lost. The purpose is to prevent the occurrence of Another object of the present invention is to be able to be used for high-load machining at the same time.
[0012]
[Means for Solving the Problems]
Therefore, in order to solve the above-described problem, the throw-away tip for drill of the present invention has a through hole for inserting a screw when attached to the drill body, and a position rotated by 180 ° about the central axis of the through hole as a rotation axis. An upper surface and a lower surface arranged to overlap with each other , an outer blade formed at each end of the upper surface and the lower surface, and a breaker groove continuous to the outer blade along the outer blade, the front Kigaiha, an arcuate step I ₁ that protrudes the cutting direction, stepped portion of the stepped I ₂ were continuously formed in the tip thickness direction is provided with, on the breaker wall of the breaker groove the front Kigaiha said is a step I ₃ of the chip thickness direction continuously provided from the stepped portion, side walls forming the step I ₁ and said step I ₂ and the step I _3, the cutting direction In With the continuously extends to the through-hole is Te, in the thickness direction, characterized in that it extends so as to divide the upper surface or the lower surface.
[0013]
According to such a configuration, the chips a stepped portion as a boundary is generated are separated, the shed chips are more and this level difference of the chip thickness direction is also provided in the breaker wall breaker groove, No contact in the breaker groove.
[0014]
As a result, it is possible to obtain excellent chip discharging performance under a wide range of conditions without causing recombination of chips even in dry processing where the chip temperature is high.
[0015]
Moreover, by providing the outer blade with a step in the cutting direction, the step portion in the cutting direction of the outer blade can be formed in an arc shape, and the mechanical strength of this portion of the outer blade is large.
[0016]
That is, when the stepped portion is only a step in the chip thickness direction, even if an attempt is made to make the corner of the protruding corner portion into an arc shape, a wall due to the step exists immediately after the stepped-down cutting edge with respect to the arc portion. As a result, normal chip disposal becomes impossible. On the other hand, if a step in the cutting direction is provided in the step portion and the step is formed in an arc shape, such a problem does not occur, and therefore cutting under a high load condition is possible.
[0017]
Further, Suroau E Lee chip drill present invention, preferably, prior Symbol outer cutter, that protrudes the cutting direction than the portion inside portion serving when mounted on the drill body becomes outside Features.
[0018]
According to this configuration, the arcuate cutting edge (corner R) provided in the step portion of the outer blade is included in the inner portion of the outer blade. Each of the outer cutting edge and the inner cutting edge of the outer blade has one corner R each serving as an outer blade. As a result, the chips generated from the outer and inner cutting blades have similar shapes.
[0019]
Therefore, it is possible to stabilize the chip discharge performance for various work materials, and it becomes very easy to take countermeasures such as a breaker shape design for stable chip discharge performance.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 shows a throw-away drill 1 equipped with a throw-away tip (hereinafter abbreviated as a tip) 4 of the present invention. This throw-away drill 1 is equipped with a tip 4 having an inner blade 2 that cuts the inner area (center portion) of the hole bottom and a tip 4 having an outer blade 3 that cuts the outer area of the hole bottom at the tip of the drill body 5. Is made up of. The throw-away drill 1 has both the inner blade 2 and the outer blade 3 formed on one tip 4, and the same tip 4 is inserted into the outer blade tip depending on the direction and position of mounting on the drill body 5. Alternatively, it is configured so that it can also be used as an inner blade tip.
[0022]
FIG. 2 shows the chip 4 alone.
[0023]
This tip 4 is configured as a plate-like tip having a substantially parallelogram in which two outer blades 3 and two inner blades 2 are disposed in the same tip, and a total of four locations can be used.
[0024]
The four cutting blades include two outer blades 3 and 3 and two inner blades 2 and 2 through holes 10 for inserting screws (not shown) when the tip 4 is attached to the drill body 5. Are arranged so as to overlap at a position rotated by 180 ° about the central axis 10a. Therefore, even if one outer blade 3 is worn or missing, the other outer blade 3 can be used instead. The same applies to the inner blade 2.
[0025]
The outer edge 3 of the chip 4, including the corner R 3a, a step I ₁ in the cutting direction (lower side in FIG. 2 (a)), step I ₂ to the chip thickness direction, are continuously formed A step 3c is provided.
[0026]
Further, a breaker groove 9 is provided on the chip discharge side of the chip 4 along the outer blade 3, and the chip discharge side is a breaker wall 9a. A step I _{3 in the} chip thickness direction is formed on the breaker wall 9a.
[0027]
As can be seen from FIG. 2, the upper surface 7 and the lower surface 6 and the two side surfaces 8, 8 constituting the chip 4 are arranged so as to overlap at a position rotated by 180 ° about the central axis 10 a of the through hole 10.
[0028]
Further, the surface b forming the steps I ₂ and I ₃ in the chip thickness direction functions as a chip separator. The chip 4 is provided with two surfaces b as chip separators, arranged so as to overlap at a position rotated by 180 ° about the central axis 10a of the through hole 10, and have a parallel positional relationship. In addition, it is desirable that the surface b is longer in order to maintain the state of the divided chips. In particular, as shown in FIG. 2, it is desirable to continue to a through hole 10 into which a screw (not shown) for chip attachment is fitted.
[0029]
According to such a configuration of the chip 4, chips are generated by being divided at the stepped portion 3 c as a boundary. The divided chips are also formed on the breaker wall 9 a of the breaker groove 9 and the step I in the chip thickness direction. _By providing _3, there is no contact in the breaker groove 9.
[0030]
As a result, it is possible to obtain excellent chip discharging performance under a wide range of conditions without causing recombination of chips even in dry processing where the chip temperature is high.
[0031]
Further, by providing the step I ₁ in the cutting direction in the outer cutter 3, it is possible to form a step I ₁ of the cutting direction in the outer blade 3 as arcuate corner R3a, this part of the outer blade 3 High mechanical strength. Therefore, cutting under high load conditions is possible.
[0032]
Incidentally, in the chip 4, and corner R 3a protruding forming the step I ₁ the cutting direction, and corner R 3b positioned in the outermost periphery portion of the outer cutter, when mounted on both the outer peripheral side direction (the drill Outer peripheral side: installed on the right side in FIG. That is, the protruding corner R 3a is included in the inner portion of the outer blade 3, and the inner portion of the outer blade 3 protrudes in the cutting direction of the outer blade 3 with the stepped portion 3c as a boundary. Yes.
[0033]
The present invention is not limited to such a form, but the advantages of this configuration are as follows.
[0034]
According to this configuration according to the present invention, the outer portion of the outer blade 3, the inner portion both corner R 3a to be subjected to cutting as the outer blade 3 has One not a one to 3b. As a result, the chips generated from the outer and inner portions have similar shapes. Since there is no great difference in chip disposability, there is an advantage that it is easy to determine the specifications of each breaker groove and to determine the cutting conditions.
[0035]
The step I _{2 in} the chip thickness direction of the outer cutter 3 is preferably in the range of 0.1 mm to 0.3 × tmm. Here, t is the maximum thickness of the chip 4.
[0036]
If the step I ₂ is less than 0.1mm, there is a risk that the effect of the stable chip division becomes difficult to obtain. Further, if the level difference I ₂ exceeds 0.3 × t, excessive stress is applied to the level difference during cutting, which may make it difficult to ensure the chip strength.
[0037]
Further, forming the step I ₁ in the cutting direction of the outer cutter 3, the protrusion amount of the corner R3a mentioned above protruding, preferably in the range of 0.2 × r~3.0 × r. Here, r is the radius of curvature of the corner R3a.
[0038]
If the level difference I ₁ is less than 0.2 × r, since the rear ends of the breaker grooves 9 along the inner side of the outer blade 3 and the outer side of the outer blade 3 are close to each other, the chip cutting action The effect may be weakened. In addition, if the dimension l ₁ exceeds 3.0 × r, excessive stress is applied to the step during cutting, which may make it difficult to ensure the chip strength.
[0039]
As mentioned above, although embodiment of this invention was illustrated, this invention is not limited to the said embodiment, As long as it does not deviate from the objective of invention, it can be made arbitrary.
[0040]
【The invention's effect】
As described above, according to the throw-away tip for drill of the present invention, at the time of dry processing or high-feed processing, the divided chips do not come into contact with each other in the breaker groove and the effect of the division is not lost. can do. At the same time, it can be used for high-load machining.
[0041]
In addition, the throw-away tip for a drill of the present invention, in the outer blade, when the outer portion protrudes in the cutting direction of the outer blade rather than the portion that becomes the outer side when mounted on the drill, Chips generated from each of the inner cutting edges have a similar form.
[0042]
Therefore, it is possible to stabilize the chip discharge performance for various work materials, and it becomes very easy to take countermeasures such as a breaker shape design for stable chip discharge performance.
[Brief description of the drawings]
FIGS. 1A and 1B are perspective views of a throw-away drill equipped with a throw-away tip of the present invention.
FIG. 2 shows a throwaway tip of the present invention alone, (a) is a front view, (b) is a right side view, (c) is a bottom view, and (d) is a perspective view.
[Explanation of symbols]
1 Throwaway drill 2 Inner blade 3 Outer blade 3a Corner R
3b Corner R
3c Step 4 Tip 5 Drill body 6 Lower surface 7 Upper surface 8 Side surface 9 Breaker groove 9a Breaker wall 10 Through hole 10a Center axis b surface (chip separator)
I steps

Claims (3)

A throw-away tip for the drill,
A through hole for inserting a screw when attaching to the drill body,
An upper surface and a lower surface disposed so as to overlap at a position rotated by 180 ° about the central axis of the through hole;
An outer blade formed at each end of the upper surface and the lower surface, and a breaker groove continuous to the outer blade along the outer blade,
Before the Kigaiha, an arcuate step I ₁ that protrudes the cutting direction, and the stepped portion of the stepped I ₂ were continuously formed in the chip thickness direction is provided,
Wherein the breaker wall of the breaker groove, and the step I ₃ of the chip thickness direction continuing from the step portion of the front Kigaiha is provided,
The side walls forming the step I ₁ , the step I ₂ and the step I ₃ extend continuously to the through hole in the cutting direction, and the upper surface or the lower surface in the thickness direction. A throw-away tip for a drill characterized by extending so as to divide . The throw-away tip for a drill according to claim 1, wherein a size of the arc-shaped step is 0.2 × r to 0.3 × r, where r is a radius of curvature of the arc. . Prior Symbol outer cutter, indexable drill according to claim 1 or 2 parts to be inside, characterized in that protrudes the cutting direction than the portion that becomes the outside when mounted on the drill body .

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