JP4384327B2 - Drill insert - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drill insert attached to a turning tool or a turning tool for drilling holes.
[0002]
[Prior art]
In drilling tools such as turning tools and turning tools for drilling holes, the inner and outer inserts are removably mounted so that the rotation trajectory crosses the tip of the tool body. I am using it. And what used these inner periphery side inserts and outer periphery side inserts in common as the same shape, and was able to be used as one kind of drill insert is also utilized widely.
[0003]
When this type of drill insert is used as an inner peripheral side insert, the inner peripheral side cutting edge mainly for cutting the inner peripheral side hole bottom surface, and when used as an outer peripheral side insert, the outer peripheral side hole bottom surface is mainly used. One drill insert is provided with an outer peripheral side cutting edge that cuts.
[0004]
Normally, when drilling is performed, the outer peripheral cutting blade rotates at a faster peripheral speed than the inner peripheral cutting blade between the inner peripheral cutting blade and the outer peripheral cutting blade. Therefore, the amount and shape of chips can be different. As a result, the inner peripheral side cutting edge and the outer peripheral side cutting edge are designed to be completely different, and in order to realize stable drilling, improvements have been made to obtain dedicated chip disposal.
[0005]
For example, in Japanese Patent Laid-Open No. 6134611, the inner peripheral side chip breaker formed on the inner peripheral side cutting edge and the outer peripheral side chip breaker groove formed on the outer peripheral side cutting edge are formed in different shapes, so that the inner peripheral side In addition, good chip disposal is realized on the outer peripheral side. Specifically, the inner peripheral chip breaker forms the breaker wall surface directly from the rake face, while the outer peripheral chip breaker groove forms a breaker wall surface on the rake face via a concave groove. By changing the degree of bending of both of the breakers, the long cutting chips produced by the outer peripheral cutting edge having a higher peripheral speed can be curled small and divided so that both can be discharged well.
[0006]
[Problems to be solved by the invention]
As described above, by making the inner chip breaker and the outer chip breaker groove different shapes, it is good for steel materials (ordinary work materials) such as carbon steel and chrome molybdenum steel as work materials Even if it is possible to achieve good chip evacuation, there is still room for improvement with respect to stainless steel and low carbon steel, which are harder materials (hard-to-cut materials). It's real.
[0007]
Specifically, in the case of a normal work material, the inner peripheral side of the chip is an umbrella-shaped chip that forms a spiral and is continuously discharged cleanly. In some cases, it becomes dumpling-like chips with entangled umbrellas intertwined, and the discharge tends to be extremely poor. As a result, clogging occurs on the inner peripheral chip, resulting in problems such as increased cutting resistance during processing and damage to the work surface of the work material due to the chip. Cannot be maintained.
[0008]
As a countermeasure, there is a possibility to improve by increasing the breaker width of the inner chip breaker or increasing the distance to the breaker wall, but it becomes impossible to freely design the shape of the adjacent chip breaker adjacent to the outer chip breaker. The shape of the side chip breaker groove itself is also affected, and conversely, the processability of the peripheral chip may be hindered.
The present invention has been made in view of such circumstances, and an object thereof is to use a single drill insert having an inner peripheral side cutting edge and an outer peripheral side cutting edge, and in particular, a work material having a stickiness. An object of the present invention is to provide a drill insert that can ensure good chip discharge even when drilling is performed.
[0009]
[Means for Solving the Problems]
  To achieve the above purpose, DeRil insertBetween top and sideOn the edgeThe firstWith cutting edgeA second different from the first cutting edgeWith a cutting bladeHaveIn the drill insert,AboveThe top surface isThe firstAlong the cutting edgeFirstBreaker groove and saidFirstAlong the breaker grooveFirstThe land,Said secondAlong the cutting edgeSecondBreaker groove andSaid secondAlong the breaker grooveSecondWith landBe equippede,The firstTop of landPart of the secondTop of landPartLower thanThe top of the first land portion is lower than the first cutting edgeIt is characterized by that.
[0010]
Also, DeRil insertIn a drill insert having a first cutting edge and a second cutting edge different from the first cutting edge at the ridge side portion between the upper surface and the side surface, the upper surface is along the first cutting edge. A first land portion along the first breaker groove and the first breaker groove, and a second land along the second breaker groove and the second breaker groove along the second cutting edge. A displacement portion between the first land portion and the second land portion, and the first land portion is lower than the second land portion with the displacement portion as a boundary. The first land portion is lower than the first cutting edge with the first breaker groove as a boundary.
Further, in a drill insert having a first cutting edge and a second cutting edge different from the first cutting edge at a ridge portion between the upper surface and the side surface, the upper surface is formed on the second cutting edge. A second breaker groove along the second land portion along the second breaker groove, the top of the second land portion is higher than the upper surface along the first cutting edge, The top part from which height differs is formed, It is characterized by the above-mentioned.
[0011]
According to these drill inserts, a land portion is provided only on a portion corresponding to the outer peripheral side cutting edge on the upper surface serving as a rake face, and a breaker of the inner peripheral side cutting blade is used as an upper surface without a rising surface, or the inner peripheral side and When a land portion having a rising surface of a breaker groove of the outer peripheral side cutting edge is formed, the chip processing capacity on the inner peripheral side is reduced by making the land portion corresponding to the inner peripheral side cutting blade lower than the outer peripheral side cutting blade. Can be increased.
[0013]
Hereinafter, the present invention will be specifically described with reference to the drawings.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
First, a drill using the drill insert of the present invention will be described.
[0015]
FIG. 1 is a view showing a drill D that uses a replaceable drill insert as a cutting blade. The drill D has a substantially cylindrical shape, and includes a shank portion S and a drill body T that are fixed to a machine tool. It is configured. In the drill body T, flute grooves F and F ′ for discharging chips from the tip to the shank side are spirally formed in the longitudinal direction. At the tips of the flute grooves F and F ′, tip pockets 3 and 5 for attaching the drill insert 1 are disposed on the surface of the drill body in the rotational direction. And the front-end | tip pocket 3 of the flute groove F is for detachably mounting | wearing with the outer periphery side insert 2 which mainly cuts an outer diameter side, and the outer peripheral surface side is open | released. The tip pocket 5 of the flute groove F ′ is for detachably mounting the inner peripheral side insert 4 that cuts the inner diameter side in the same manner as the outer peripheral side insert 2, and the rotational axis direction of the drill body T is open. Has been. The pockets 3 and 5 are formed so that the respective inserts can be attached in a relationship in which the outer peripheral side insert 2 and the inner peripheral side insert 4 to be attached are rotated about 90 degrees around the clamp screw L as a rotation center. Yes.
[0016]
And the drill insert 1 which has the same magnitude | size and shape mentioned later in this pocket 3 and 5 is fixed with the clamp screw L. FIG.
[0017]
Next, the drill insert of this invention is demonstrated.
[0018]
FIG. 2 is a front view showing the external shape of the drill insert of the present invention, and FIG. 3 is a side view thereof. The drill insert indicated by 1 as a whole has a polygonal shape, and a cutting edge is formed over the entire circumference of the insert at the ridge side portion of the side surface 7 serving as a flank and the top surface 8 serving as a rake face. These cutting blades have a pair of opposed cutting blades having the same function, and as a whole, formed in the thickness direction of the insert body, at the center O1 of the through hole 9 for inserting the clamp screw. On the other hand, it is formed in the shape of point symmetry.
[0019]
Among these cutting edges, 12, 12 'is an inner peripheral cutting edge, and 14, 14' constitutes an outer peripheral cutting edge.
[0020]
Between the inner peripheral side cutting blades 12 and 12 ', there is a biting cutting blade portion 30 that first comes into contact with the work material during drilling as an inner peripheral side cutting blade. On the other hand, the outer peripheral cutting edges 14, 14 ′ have two corner R portions 15, 16 at both ends of the cutting edge 14, and form a projecting shape portion 18 protruding from the drill insert 1 as a whole. Further, the corner R portion 16 between the outer peripheral cutting blades 14 and 14 ′ functions as a biting cutting blade portion that first comes into contact with the work material during drilling.
[0021]
Here, the corner R portions 15 and 16 are formed so that the angles α and α ′ formed by straight lines continuous with the curved portion are close to a right angle and are in a range of approximately 60 ° to 105 °.
[0022]
The cutting edges are machined into a sharp edge shape with both the inner peripheral cutting edges 12, 12 'and the outer peripheral cutting edges 14, 14' so as to be suitable for difficult-to-cut materials and deep drilling so as to reduce the cutting resistance during the processing. .
[0023]
This point will be described using a cross-sectional view.
[0024]
FIG. 4 is a cross-sectional view taken along the line AA in FIG. The side surface 7 including the outer peripheral cutting edge 14 functions as a relief surface, and the upper surface 8 functions as a rake surface. The upper surface 8 includes a land 31 and a breaker groove 32 inside the cutting edge 14, and a land portion 34 is formed from a rising surface 33 of the breaker groove.
[0025]
The breaker groove 32 has a shape that is larger than the land 31, and forms a rising surface 33 so that the land portion 34 is higher than the land 31 when viewed in the height direction of the drill insert 1. . By forming the land portion 34 at such a position that is highly curved and rises high, the chips cut by the outer peripheral cutting edge 14 can be curled and divided into small pieces.
[0026]
FIG. 5 is a cross-sectional view taken along the line BB in FIG. 2, and is a cross-sectional view showing the shape of the edge of the outer peripheral cutting edge 14 ′. The outer peripheral cutting edge 14 ′ is located inside the cutting edge 14 in the drilling process, and the cutting generated by the cutting edge 14 due to the presence of the corner R portion 16 is divided during the drilling process. Generate trash.
[0027]
This cutting edge shape has a breaker groove 32 ′ that is narrower and shallower than the cutting edge 14 described above, and a land portion 34 ′ that is higher than the land portion 34 described above. The shape is substantially similar.
[0028]
Next, the cutting edge shape of the inner peripheral side cutting edges 12, 12 'will be described.
[0029]
As shown in FIG. 2, the inner blade side cutting blade 12 forms cutting blades 12 and 12 ′ from a corner R portion 15 located in the vicinity of the center axis of the drill, and the two cutting blades are convex-shaped. Is formed. And it has the cutting blade part 30 at the corner | angular part located between two cutting blades 12 and 12 '.
[0030]
The cutting blade shape is substantially the same for the two cutting blades 12 and 12 ′, and has the shape shown in FIG. 6 which is a cross-sectional view taken along the line CC in FIG. Specifically, a flat breaker surface 36 in which no land portion is provided on the upper surface through the land 31 from the cutting blades 12 and 12 ′ is formed.
[0031]
The outer peripheral cutting edges 14, 14 'and the inner peripheral cutting edges 12, 12' both have a large rake angle β1 (corresponding to the outer peripheral cutting edges 14, 14 ') and β2 (inner peripheral side) to reduce cutting resistance. (Corresponding to cutting edges 12, 12 ').
[0032]
In particular, the outer peripheral cutting edge 14 has the following problems when the rake angle β1 is small. That is, the protruding shape portion 18 of the outer peripheral cutting edge 14 is a portion that first bites into the work material during cutting, but if the rake angle β1 is small and is subjected to a large resistance, a slight amount is required. Although the amount is large, the protrusion diameter is twisted in the direction opposite to the rotation direction and on the inner peripheral side, so that the machining diameter is reduced. And since the processing is continued with the small processing diameter, the hole surface and the holder come into contact during processing, or the insert and the hole surface come into contact when the holder is removed after processing. As a result, the finished surface of the hole surface may be defective. Also, in order to secure a balance between the cutting resistances of the outer peripheral cutting edge with a large amount of cutting and the inner peripheral cutting edge with a small amount of cutting, the rake angle β1 of the outer peripheral cutting edge is set to be larger than the rake angle β2 of the inner peripheral cutting edge. Largely formed.
[0033]
On the other hand, it is preferable that the inner peripheral cutting edge 12 ′ has a large rake angle β2, but in order to balance the cutting resistance and prevent the protruding shape portion 18 of the outer peripheral cutting edge 14 from being twisted, It is preferable to receive a cutting force somewhat larger than that of the protruding shape portion 18. Therefore, the rake angle β1 of the outer peripheral side cutting edge is formed larger than the rake angle β2 of the inner peripheral side cutting edge.
[0034]
These rake angles in the drill insert of the present invention are appropriately determined depending on the strength of the base metal of the insert and the cutting process conditions, and β1 is formed at 23 to 33 degrees and β2 is formed at 12 to 22 degrees, respectively. In this embodiment, β1 is formed at 27 degrees and β2 is formed at 18 degrees. When this rake angle is increased, the cutting resistance decreases, but the cutting edge strength decreases. Conversely, when the rake angle is decreased, the cutting resistance increases, but the cutting edge strength increases. In the present invention, in order to realize a large rake angle, a land 31 is formed on the inner peripheral side of the cutting edge, and a high cutting edge strength and a small cutting resistance are provided in a balanced manner. Although the width of the land depends on the size of the insert, it is desirable to form a width of approximately 0.02 to 0.07 mm.
[0035]
Further, the depth of the breaker is desirably deeper on the outer peripheral side than on the inner peripheral side, and the outer peripheral side cutting edge also cuts the outermost peripheral portion (in this embodiment, the protruding shape portion 18). It is desirable to form a breaker corresponding to the cutting edge 14) deeper from the viewpoint of cutting of chips and discharging. Specifically, the outer peripheral breaker groove h1 (corresponding to the cutting edge 14) is preferably 0.15 to 0.35 mm, and h2 (corresponding to the cutting edge 14 ') is preferably 0.05 to 0.20 mm.
[0036]
Furthermore, the width of the breaker grooves 32 and 32 ′ formed along the outer peripheral cutting edges 14 and 14 ′ is such that the breaker grooves 32 along the cutting edge 14 that cut the outermost peripheral portion are formed wider. In this embodiment, the breaker groove 32 along the cutting edge 14 of the protruding shape portion 18 is a large breaker groove that includes the entire protruding shape portion 18. Further, the breaker groove 32 of the cutting edge 14 of the projecting shape portion 18 is deep and the rising surface 33 is low, while the breaker groove 32 ′ of the other cutting edge 14 ′ of the outer peripheral cutting blade is shallow, and The rising surface 33 'was raised.
[0037]
The reason why the shape of the breaker groove along the outer peripheral cutting edge is changed depending on the part will be described next.
[0038]
First, since the chips of the cutting edge 14 along the protruding shape portion 18 have a wide width and a large rigidity (see a width d4 in FIG. 12), they have a property of being easily bent. If such chips are made shallower in the breaker groove so that the chips strongly hit the groove surface, the chips will curl immediately. When the curled chips hit the rising surface 33, the chips are easily clogged and a large cutting resistance is generated. Therefore, in this embodiment, the breaker groove 32 is formed deeply so that the chips do not hit the breaker groove surface, and the chips are smoothly discharged without being curled by force. The width was made large and the rising surface 33 was made low.
[0039]
On the other hand, the chip of the other part (cutting blade 14 ') of the outer peripheral side cutting blade has a short effective blade length (see width d5 in FIG. 12) and the chip width is narrow. This narrow chip has a property that it is difficult to bend because of its low rigidity. Therefore, in the present embodiment, the breaker groove 32 ′ is shallow and narrow, and the rising surface 33 ′ is high so that the chips hit the breaker groove surface and bounce, and bend at the rising surface with certainty.
[0040]
In this way, the chip disposability is improved by adjusting the width of the breaker groove and the like.
[0041]
The widths of the breaker grooves 32 and 32 'vary depending on the size of the drill insert, but are preferably formed in the range of W1 of 1.6 to 3.5 mm and W2 of 0.9 to 2.0 mm. Further, the height of the land portions 34, 34 'with respect to the cutting edge is 0.05 to 0.13 mm for h3 (corresponding to the cutting edge 14), and 0.13 to 0.2 mm for h4 (corresponding to the cutting edge 14'). It is good to form each in the range.
[0042]
Returning to FIG. 2, the shape of the land portion corresponding to the outer peripheral cutting edge will be described.
[0043]
The land portions 34, 34 'used in the present invention refer to portions formed in an island shape on the rake face.
[0044]
The land portions 34, 34 ′ are formed to ensure the width and height of the rising surfaces 33, 33 ′ of the breaker grooves 32, 32 ′ of the outer peripheral cutting blades 14, 14 ′. , 14 'and a rising surface corresponding to the length of 14'.
[0045]
On the other hand, the rake face where the inner peripheral cutting edge is present ensures a sufficient chip discharge property, so in this embodiment, a flat breaker surface 36 without land portions is formed to ensure a sufficiently wide surface. Yes.
[0046]
Therefore, the boundary with the rake face along the inner peripheral side cutting edge of the land portions 34, 34 ′ is along a diagonal line that connects a pair of corners that are located approximately diagonally to the center O 1 of the drill insert 1. Is formed. Of these land portions 34, 34 ', the land portion 34 corresponding to the outer peripheral cutting edge 14 adjacent to the corner R15 has an end portion on the inner peripheral side cutting surface on the inner peripheral side with respect to the diagonal line. I'm overhanging. By adopting such a configuration, it is possible to provide a large breaker groove for finely dividing the chips along the outer peripheral cutting edge 14. In this case, since the inner peripheral cutting edge 12 adjacent to the corner R15 has a relationship including the rotation center axis O3 (see FIG. 12) of the drill, a wide and flat breaker surface for efficiently discharging umbrella-shaped chips. However, since the rotation center axis O3 is positioned in the inner peripheral cutting edge direction slightly from the corner R, the inclined portion 40 of the land portion 34 with the inner peripheral cutting blade breaker groove surface is , And can be projected to the inner peripheral side from the diagonal line described above.
[0047]
With this configuration, a wide and deeply curved large groove for the outer peripheral cutting edge can be secured, and a flat and large breaker groove surface 36 can be formed on the inner peripheral side.
[0048]
In the present embodiment, the breaker surface 36 is a flat surface without a land portion. However, the breaker surface 36 may have a shape other than a flat surface, such as a curved surface shape without rising, such as a land portion not formed. .
[0049]
Next, the relationship between the land portion formed on the outer peripheral side and the upper surface along the inner peripheral cutting edge will be described.
[0050]
FIG. 7 showing this relationship shows an EE cross-sectional view in FIG. This cross-sectional view is from the outer peripheral cutting edge 14 ′ to the land → the outer peripheral cutting edge breaker groove → the land portion → the upper surface portion of the inner peripheral cutting edge → the land portion → the outer peripheral cutting edge breaker groove → land → the outer peripheral cutting edge 14. It leads to. From FIG. 7, the depth relationship of the breaker groove, the height relationship between the land and the land portion, and the height relationship between the land portion corresponding to the outer peripheral side cutting edge and the upper surface corresponding to the inner peripheral side cutting blade can be understood. .
[0051]
That is, the depth h1 of the breaker groove 32 of the cutting edge 14 that cuts the outermost peripheral portion of the outer peripheral side cutting blade is larger than the depth h2 of the breaker groove 32 ′ of the other portion 14 ′, and the land portions 34, 34. 'Is higher than the lands 31 of the outer peripheral cutting edges 14, 14 ′. On the contrary, the breaker surface 36 provided on the upper surface of the inner peripheral cutting edge is formed lower than the lands 31. By forming in this way, the chip disposal of the inner peripheral cutting edges 12, 12 'can be improved while satisfying the chip disposal of the outer peripheral cutting edges 14, 14'.
[0052]
Next, the relationship between the top surfaces of the outer peripheral land portions will be described with reference to FIG. FIG. 8 is a cross-sectional view taken along the line JJ in FIG. 2. From the inner peripheral cutting edge 12 ′ to the land → the upper surface portion of the inner peripheral cutting edge → the outer peripheral land portion 34 ′ → the step portion → the outer peripheral land portion 34 → The upper end portion of the inner peripheral side cutting edge → land → the inner peripheral side cutting blade 12 is reached. From FIG. 8, the outer peripheral side land portion 34 along the cutting edge 14 ′ of the other portion with respect to the top surface of the outer peripheral side land portion 34 along the cutting edge 14 cutting the outermost peripheral portion of the outer peripheral side cutting blade. You can see that the top of 'is raised.
[0053]
As described above, the outer surface side land portions 34 and 34 'have the top surface of the land portion 34 corresponding to the cutting edge 14 that cuts the outermost periphery side somewhat lower than 34', as described above. Since the chips of the cutting blade 14 are wide and easily bent, the rising surface 33 is formed low in order to bend the chips without difficulty, whereas the other 34 ′ portion of the outer peripheral cutting blade is formed. This is because the cutting surface (cut edge 14 ') is narrow and difficult to bend, so that the rising surface 33' is raised so as to be surely bent at the rising surface.
[0054]
In the case of a drill insert having a small machining diameter, the width of the chips on the outer peripheral side cutting blades 14 and 14 ′ is almost the same between the cutting blade 14 of the projection-shaped portion 18 and the cutting blade 14 ′ of the other portions. There is no problem even if the top surfaces of both land portions are the same height.
[0055]
In the above-described example, the breaker surface corresponding to the inner peripheral cutting edge is flat, and the breaker rising surface is not formed. However, an inner peripheral land portion that is lower than the land portion corresponding to the outer peripheral cutting edge can be provided in a range that does not impair the discharge performance of the inner peripheral chip. At this time, it is desirable that the height of the top surface of the inner peripheral side land portion be lower than the height at which the cutting edge is located in the height direction of the drill insert. FIG. 9 is a front view of a drill insert provided with such a low inner circumferential land portion 70, and FIG. 10 is a cross-sectional view taken along a line G-G showing the relationship between the cutting edge and the land portion.
[0056]
Referring to FIGS. 9 and 11, drill insert 1 ′ includes an outer peripheral side land portion and an inner peripheral side land portion 70, and a gently inclined slope portion 40 and a sudden rise at the boundary between both end portions. A step portion 50 is formed. Among these, the inclined portion 40 formed between the land portion 34 and the inner peripheral breaker groove 71 is in contrast to the step portion 50 formed between the land portion 34 ′ and the inner peripheral breaker groove 71. A gentle slope is formed. Moreover, as is apparent from FIG. 9, the inclined surface 40 has a substantially triangular shape with the apex angle on the corner R15 side. This is because, particularly when the machining diameter is small, by forming such an inclined portion 40, the inner peripheral side chips formed in an umbrella shape centering on the corner R side can be made more effective in a clean umbrella shape. Thus, the action of the flat inner peripheral side breaker 36 also works, and the discharge efficiency can be increased.
[0057]
And FIG. 11 is sectional drawing between II for demonstrating the height relationship between land parts.
[0058]
In this modified example, since the inner peripheral breaker groove 71 has a low rising surface 72, the umbrella-shaped chips formed by the inner peripheral cutting edge 12 'have a smaller turning radius. Is possible. In particular, when using a small insert, the flute of the drill body is also small. Therefore, it is desirable to make the chips themselves smaller, and the land portion having such a low rising surface is effective.
[0059]
Further, in the case of such a small drill, it is difficult to form a sufficient space as a guide part for discharging chips from the insert to the flute. Therefore, it is desirable that the inclined portion 40 between the outer peripheral side land portion and the inner peripheral side land portion adjacent to the corner R portion positioned near the rotation center of the drill be a surface having a particularly gentle inclination angle.
By carrying out like this, since the flow of a chip is not inhibited by this inclined part 40, the chip conveyance nature to the flute which discharges the inner circumference side chip is improved. This is particularly effective for smaller drill inserts than the previous embodiment.
[0060]
Another reason for making the inclination of the inclined portion 40 gentle is as follows.
[0061]
That is, when the inner peripheral side land portion 70 is not provided, the insert tends to be easily discharged without curling the chips on the inner peripheral side cutting edge when the machining diameter is small. Therefore, by applying chips to the land portion 70 and further forming an inclined portion 40 as a rising surface on the corner R15 side where the chips hit the back of the land portion 70, the chips hit the two-step rising surface. It ’s a beautiful umbrella. However, if this inclined surface 40 rises suddenly, the chips are more likely to be an irregular umbrella shape than a clean umbrella shape, so in this embodiment, the inclined portion 40 is formed on a gentle slope, In addition, by making the slope more gentle in the back of the inclined portion 40, the chips can be discharged in a clean umbrella shape.
[0062]
Next, the relationship between the two drill inserts 1 (the outer peripheral side insert 2 and the inner peripheral side insert 4) during drilling will be described with reference to FIG.
[0063]
FIG. 12 is a perspective arrangement view seen from the outer periphery of the side surface of the drill body T, where O3 is the rotation center line of the drill T, T2 is the outer periphery line of the drill body T, and T3 is the inner surface to be drilled. Show. In FIG. 12, the outer periphery side insert 2 and the inner periphery side insert 4 are indicated by solid lines, the outer periphery side insert 2 is viewed from the rake face side, and the inner periphery side insert 4 is the attachment surface side to the pocket. The state seen from each is shown. Moreover, the outer periphery side insert 2 shown with a dotted line is the overlap with the inner periphery side insert 4 which the outer periphery side insert 2 rotated 180 degree | times regarding the rotation locus | trajectory of the outer periphery side insert 2 centering on the axis | shaft T1 of the drill main body T. Explains the condition.
[0064]
The outer peripheral side insert 2 is attached to the pocket portion 3 so that the corner R portion 15 is located outside the outer peripheral surface of the drill body T, and the inner peripheral side insert 4 positions the corner R15 outside the rotation center line O3. Installed. The two drill inserts are configured such that the outer peripheral cutting edge 14 ′ and the inner peripheral cutting edge 12 ′ intersect at a point P in the rotation trajectory.
[0065]
As a result, the inner peripheral cutting edges 12 and 12 'have a width d1 from the rotation center O3 to the crossing point P as a cutting region of the inner peripheral cutting edge, and a width from the point P to the machining inner surface T3 is the outer peripheral cutting edge. It becomes a cutting area. “D1 + d2” represents the machining radius, and d3 represents the machining diameter. Moreover, d4 shows the blade length of the cutting edge 14 of the protrusion-shaped part 18 among outer peripheral side cutting blades, and d5 shows the effective blade length of the other part of the outer peripheral side cutting blade.
[0066]
At this time, in the present invention, the cutting area widths d1 and d2 of the inner peripheral cutting edge 2 and the outer peripheral cutting edge 4 are set to be substantially the same, and the characteristic breaker shape or land as described above as the drill insert is set. By providing the portion, it is possible to ensure the balance of the cutting areas d1 and d2 and improve the chip discharge performance of the inner peripheral cutting area d1. As a result, the outer peripheral side chips are divided into two in the width direction at the corner R portion 16, and are further finely divided in the length direction by the action of the breaker groove and the land portion, so that the flute groove F (outer peripheral side). Is discharged. On the other hand, due to the presence of a wide breaker surface, the inner peripheral side chips can be efficiently discharged to the flute groove F ′ (inner peripheral side) even when processing a sticky work material.
In addition, this invention can be made into arbitrary forms, as long as the relationship between the top face of the land part formed in the outer peripheral side cutting edge and the shape of the rake face of an inner peripheral side cutting edge is satisfied. For example, the outline shape of the drill insert 1 may be a polygonal shape other than a quadrangle, and the protruding shape portion 7 may not be provided.
[0067]
【The invention's effect】
According to the present invention described above, the land corresponding to the inner peripheral side cutting edge is formed when the land portion having the rising surfaces of the breaker grooves of the inner peripheral side and outer peripheral side cutting blades is formed on the upper surface serving as the rake face. By making the part lower than the outer peripheral cutting edge, or by setting the land portion only in the part corresponding to the outer peripheral cutting edge and making the upper surface without the rising surface on the breaker surface of the inner peripheral cutting blade, It becomes possible not to reduce the chip processing capacity on the inner peripheral side.
[0068]
This is particularly effective when processing a sticky work material.
[Brief description of the drawings]
FIG. 1 shows a drill D using a replaceable drill insert as a cutting edge.
FIG. 2 is a front view showing an external shape of a drill insert according to the present invention according to the first embodiment.
FIG. 3 is a side view of the drill insert of FIG. 2;
4 is a cross-sectional view taken along the line AA in FIG.
5 is a cross-sectional view taken along the line BB in FIG.
6 is a cross-sectional view taken along the line CC in FIG. 2. FIG.
7 is a cross-sectional view taken along line EE in FIG.
8 is a cross-sectional view taken along line JJ in FIG.
FIG. 9 is a front view showing the external shape of a drill insert according to the present invention according to a second embodiment.
10 is a cross-sectional view taken along the line GG in FIG.
FIG. 11 is a cross-sectional view taken along the line II in FIG.
12 is a see-through arrangement view seen from the outer periphery of the side surface of the drill body T. FIG.
[Explanation of symbols]
1 Drill insert
12, 12 'Inner peripheral cutting edge
14, 14 'outer peripheral cutting edge
15, 16 Corner R part
18 Protruding shape
32, 32 'outer peripheral breaker groove
34, 34 'Outer peripheral land
36 Breaker surface without riser
40 Inclined part
70 Inner peripheral land
71 Inner peripheral side breaker groove

Claims (7)

In the drill insert having a first cutting edge and a second cutting edge different from the first cutting edge at the ridge side between the upper surface and the side surface,
The upper surface includes a first breaker groove along the first cutting edge and a first land portion along the first breaker groove;
A second breaker groove along the second cutting edge and a second land portion along the second breaker groove,
The top of the first land is lower than the top of the second land,
The drill insert, wherein a top portion of the first land portion is lower than the first cutting edge. In the drill insert having a first cutting edge and a second cutting edge different from the first cutting edge at the ridge side between the upper surface and the side surface,
The upper surface includes a first breaker groove along the first cutting edge and a first land portion along the first breaker groove;
A second breaker groove along the second cutting edge and a second land portion along the second breaker groove,
A displacement portion between the first land portion and the second land portion;
The first land portion is lower than the second land portion with the displacement portion as a boundary,
The first land portion is lower than the first cutting edge with the first breaker groove as a boundary. The drill insert according to claim 2, wherein the displacement portion is an inclined portion. In a drill insert having a first cutting edge and a second cutting edge different from the first cutting edge at the ridge side between the upper surface and the side surface,
The upper surface includes a second breaker groove along the second cutting edge and a second land portion along the second breaker groove,
The top of the second land portion is higher than the top surface along the first cutting edge;
A drill insert characterized in that tops having different heights are formed. On the side surface on which the second cutting edge is formed, a protruding shape portion having two corner R portions is formed,
The said 2nd cutting blade is provided with the protruding cutting blade part formed in the edge of the said upper surface and the said protruding shape part, and the cutting blade part connected to the said protruding shape part in any one of Claim 1 to 4 The described drill insert. The protruding width of the breaker groove corresponding to the cutting portion, drill insert before Symbol cutting edge portion in the width wider than claim 5, wherein the corresponding breaker groove. The first cutting edge is an inner peripheral cutting edge provided on the inner peripheral side of the tip of the drill body, and the second cutting edge is provided on an outer peripheral side provided on the outer peripheral side of the first cutting edge. The drill insert according to claim 1, wherein the drill insert is a blade.

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