JP3532031B2 - Drill inserts and indexable drills - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill insert mounted on a rolling tool for drilling and a throw-away drill as the rolling tool.

[0002]

2. Description of the Related Art As a drill tool for drilling holes, the outer diameter insert on the outer diameter side and the inner blade insert on the inner diameter side are detachably mounted so that the mutual rotation loci intersect at the tip of the tool body. What has been done has been used.

FIG. 11 shows a conventional drill insert 10 used in such a drill tool and an arrangement when the drill insert 10 is mounted on a drill tool body T.

This drill insert 10 is a polygonal plate-shaped body having a cutting edge formed on the ridge of the upper surface 11, and as shown in the figure, a tool body T of one throw-away drill. Two of them are the outer blade insert 12 and the inner blade insert 13, respectively, which are the upper surfaces 11 and 11 in the same rotation direction.
Will be installed. Further, among the cutting blades formed on the outer blade insert 12 and the inner blade insert 13, the rotation trajectories of the cutting blades serving as the bottom cutting blades 15 intersect with each other, and cover from the central axis T1 of the tool body T to the side surface T2. To do.

FIG. 11 (b) shows the radial load force generated in each of the outer blade insert 12 and the inner blade insert 13 when cutting is performed by a throw-away drill equipped with the drill insert 10. In the conventional drill insert 10 shown in the figure, a radial load applied to the inner blade insert 13 is generated along the bottom cutting edge 15 of the inner blade insert 13 from the central axis T1 as shown in FIG. The blade insert 12 is generated in the reverse rotation direction (+ direction) with reference to the radius connecting the corner R portion 14 and the central axis T1 of the tool body T due to the cutting resistance received by the corner R portion 14 that cuts the outer wall.

As a result, the combined force of the load forces in the radial direction is deflected toward the inner blade insert 13 side, that is, in the direction in which the hole diameter decreases during machining, and when the drill tool is removed from the workpiece, the outer blade insert 12 Contact the wall of the hole and damage the finished surface, and at the same time, if it is removed by rapid feed, the corner R part 14 of the outer blade insert 12 will hit the wall strongly, while if it is removed by cutting feed, the number of contacts will increase and There is a possibility that the R portion 14 may be greatly damaged.

[0007]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the present invention provides
An object of the present invention is to provide a drill tool that can be machined into a good finished surface without coming into contact with the outer blade insert and the hole wall when the drill tool is removed from the work.

[0008]

In order to solve the above-mentioned problems, the present invention is a drill insert in which cutting edges are formed on the respective ridges of the upper surface of a polygonal plate, and at least one of them is provided. In the above cutting blade, a linear cutting blade portion provided with a protruding portion having a pair of corner R portions (4) and (5) on one end side and a non-projecting portion on the other end side and provided at the tip of the protruding portion. And the straight portion of the non-protruding portion are made non-parallel in a plan view, and the intersections of the straight lines in these linear cutting edge portions are located on the side of the projecting portion, and the pair of corners R The part has an angle formed by a straight line continuous to the curved portion of 60 ° to 105 °, and one of the corners R of the part is continuous with the cutting edge adjacent to the cutting edge on which the non-protruding portion is formed, The above for the length of the side where the part is formed The ratio of the width of the protruding portion is 2/5 to 3/5, and the drill insert is detachably attached to the inner diameter side and the outer diameter side of the tip of the tool body having a substantially cylindrical shape. In a throw-away drill that is mounted, the drill insert is arranged on the outer diameter side so that the cutting edge forming the protrusion is on the tip side of the tool body, and the linear cutting edge on the tip of the protrusion is also provided. Is inclined from the inner diameter side of the tool body toward the outer diameter side toward the rear end side of the tool body, and the linear cutting edge portion of the non-projecting portion is directed from the outer diameter side to the inner diameter side of the tool body. There is provided a throw-away drill characterized by being inclined toward the rear end side of the tool body.

[0009]

The drill insert of the present invention has a corner R having a pair of corner R portions (4) and (5) at the corners of a polygon.
A radial load of the outer cutter insert is formed by using this drill insert at the tip of the tool body as an outer cutter insert on the outer diameter side so that the protrusion faces the hole bottom side. Is directed toward the rotation direction side (− direction), whereby the resultant force direction is directed from the central axis to the outer blade insert side.

Therefore, the tool body is bent toward the outer blade insert side, and as a result, the machining diameter is increased. Therefore, when pulling out the throw-away drill from the processed hole, the drill tool can be pulled out from the work without the outer blade insert coming into contact with the hole wall.

Further, as another action of the drill insert of the present invention and the throw-away drill using the same, an inner corner R portion among the corner R portions constituting the protruding portion of the outer blade insert facing the hole bottom side. Since (5) divides the chips from the hole bottom side, the chips on the outer blade insert side are divided into small pieces and discharged.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a drill insert 1 according to the present embodiment. The drill insert 1 has a polygonal shape, and a cutting edge is formed on a ridge portion of an upper surface 2. Of these cutting edges, a point is formed with respect to a central axis of the insert. Two sides having a symmetric relationship are formed in a V shape as the main cutting edge 3, and a pair of corner R portions 4 and 5 are provided at one end of each of the remaining two sides, that is, at the corners of the polygon. A protruding portion 6 that is formed and slightly protrudes outward is formed. The linear cutting edge portion provided at the tip of the protruding portion 6 and the linear cutting edge portion of the non-projecting portion are non-parallel in a plan view. Further, the intersections of the straight lines in these linear cutting edge portions are located on the side of the projecting portion 6.

As shown in FIG. 3, the width w of the protrusion 6 is about 1/2 of the length l of the side where the protrusion 6 is formed.
Of the pair of corner R portions, the corner R portion 4 of the corner portion of the polygon which is continuous with the main cutting edge 3 has a radius of curvature R = 0.35.
.About.0.45, the radius of curvature of the corner R portion 5 on the other side is R = 0.2 to 0.3, and the corner R portion continuous with the main cutting edge is made larger.

Here, the corner R portions 4 and 5 are such that the angle formed by the straight lines continuous to the curved portions is close to a right angle, and the angle is 60 ° to 105 °.
Says in the range of °.

FIG. 2 shows a throw-away drill D to which the above-mentioned drill insert 1 is attached. This drill D is an outer cutter insert 7 for cutting the outer diameter side mainly on the tip side of a substantially cylindrical tool body T. A pocket t1 for mounting the drill insert 1 as the above and a pocket t2 for mounting the drill insert as the inner blade insert 8 for cutting the hole bottom are formed.

Next, FIGS. 3 and 4 show an arrangement example when the drill insert 1 is mounted on the tool body T. As shown in FIG. FIG. 3 is a perspective layout view seen from the side surface T2 side of the tool body, and FIG. 4 is a layout view seen from the bottom surface side of the tool body. In addition,
In FIG. 3, the outer cutter insert 7 indicated by the dotted line is for showing the relationship between the trajectory of the outer cutter insert 7 and the trajectory of the inner cutter insert 8, and is shown at a position where the outer cutter insert 7 represented by the solid line is rotated by 180 °. ing.

As shown in these figures, two drill inserts 1 are mounted on one tool body T as an outer blade insert 7 and an inner blade insert 8, and both are mounted with their upper surfaces 2 oriented in the same rotational direction. To be done. That is, as shown in FIG. 4, the upper surface 2 of the outer blade insert 7 and the upper surface 2 of the inner blade insert 8 face 180 ° in opposite directions. And
The rotation trajectories of the bottom cutting edge 9 intersect and the central axis T of the tool body T
It is installed so as to cover 1 to the side surface T2.

As the outer blade insert 7, the main cutting edge 3 is mounted on the side surface T2 so that one of the protrusions 6 is the tip of the tool body, and the other inner blade insert 8 is , The main cutting edge 3 is mounted downward. Further, the linear cutting edge at the tip of the protruding portion 6 is inclined from the inner diameter side of the tool body toward the outer diameter side toward the rear end side of the tool body, and the linear cutting edge portion of the non-projecting portion is The tool body is inclined toward the rear end side from the outer diameter side toward the inner diameter side.

In FIG. 4, straight arrows indicate the radial load force applied to the outer blade insert 7 during cutting and the inner blade insert 8 for the drill insert 1 installed as the upper blade insert 7 and the inner blade insert 8. Direction of combined force as a sum of such radial load forces (combined force direction N)
As shown in the figure, the combined force is generated from the central axis T1 on the side opposite to the rotation direction (direction of +) with reference to the upper surface 2 of the outer blade insert 7.

Since the polygonal drill insert 1 constructed as described above has a pair of corner R portions formed at the corners of the polygon, the protrusion 6 having these corner R portions 4 and 5 is removed. By arranging the blade insert 7 on the hole bottom side, the radial load direction of the outer blade insert 7 is directed toward the rotation direction side (− direction), whereby the combined force direction N is from the central axis T1 to the outer blade insert. Go to 7 side. Therefore, the tool body T is bent toward the outer cutter insert 7 side, and as a result, the drill tool can be removed from the work without the outer cutter insert 7 and the hole wall coming into contact with each other.

Further, as another operation of the drill insert 1 of the present invention, among the corner R portions 4 and 5 constituting the protruding portion 6 of the outer blade insert 7 facing the hole bottom side, the main cutting edge 3 is continuous. Since the inner corner R portion 5 which is not formed divides the chips from the hole bottom side, the chips on the outer blade insert 7 side are divided into small pieces and discharged.

The ratio U of the width w of the protrusion 6 to the length l of the side where the protrusion 6 is formed is preferably in the range of 2/5 to 3/5. On the other hand, when the ratio U is out of this range, the radial load direction of the outer blade insert 7 becomes the + direction, and as a result, the combined force direction N also becomes the inner blade insert 8 side. There is a risk that

Next, another embodiment of the present invention will be described with reference to FIGS.
It will be explained by 0. It should be noted that these figures respectively correspond to FIGS. 3 and 4. That is, it is a layout view of only the drill insert of the throw-away drill, in which the upper side shows the arrangement seen from the side surface side and the lower side shows the arrangement from the bottom surface side. Further, the drill inserts 1 shown by the dotted lines are inner blade inserts 8, respectively, and the inner blade inserts 8 shown by the solid lines are in a state of being rotated by 180 °, whereby the outer blade insert 7 and the inner blade insert 8 are shown.
The relationship of the rotation locus of is shown.

First, FIGS. 5 to 6 show an embodiment in which the drill insert 1 having the same shape is used as the outer blade insert 7 and the inner blade insert 8.

The drill insert 1 shown in FIG. 5 is basically a parallelogram and has a pair of corner corners 10 and 10 having a pair of corner R portions 4 and 5 at the point-symmetrical positions. Two pieces are formed in common with one corner R portion 4 being formed in total, four pieces in total.

The drill insert 1 shown in FIG. 6 is basically an equilateral triangle, and each of the corners is formed with the above-mentioned protrusion 6 continuous with the main cutting edge 3.

Next, FIGS. 7 to 10 show embodiments in which drill inserts 1 and 1 having different shapes are used as the outer blade insert 7 and the inner blade insert 8, respectively.

Of these, FIGS. 7 to 9 show that the outer cutter insert 7 has the above-mentioned basic shape of an equilateral triangle and each corner portion 4 has a triangular shape.
Drill insert 1 in which the above-mentioned protrusion 6 is formed
8 is used as the inner blade insert 8, while in the embodiment of FIG.
In the embodiment described above, a drill insert 1 in which the protrusions 6 are basically formed in the respective corner portions 40 of a quadrangle is used, and in the embodiment shown in FIG. 9, a hexagonal drill insert 1 is used.

Further, in the embodiment shown in FIG. 10, a quadrangular drill insert 1 is basically used as the inner blade insert 8, and the outer blade insert 7 is basically quadrangular at one corner 40 and has a thick projection. The drill insert 1 formed with 6 is used.

Of these, the action of using the inner blade insert 8 having the protrusion 6 as in the embodiment of FIGS. 5, 6 and 8 and orienting the protrusion 6 toward the hole bottom side As an effect, the radial load direction of the inner blade insert 8 is directed toward the rotation direction side, so that the outer blade insert 7
The direction of the combined force of the radial load of the inner blade insert 8 and the tendency toward the outer blade insert 7 side becomes larger, and the machining diameter becomes larger. Furthermore, the corner R of the inner blade insert 8
Since the part divides the chips from the hole bottom side, the chips on the inner blade insert 8 side are also divided into small pieces and discharged.

As shown in FIG. 10, the action and effect of making the protruding portion 6 thick in the outer blade insert 7 are as follows.
By the radial load direction of the outer blade insert 7 being directed toward the rotation direction side, the combined force of the radial load of the insert 8 and the inner blade insert 7 is more likely to be directed toward the outer blade insert 7 side. Larger diameter.

[0032]

Experimental Example An experimental example of the present invention will be described below. In the drill insert 1 of FIG. 1, the ratio U of the width w of the protrusion 6 to the length 1 of the side on which the protrusion 6 is formed is 1/3, 2/5, 1/2, 3 /, respectively. The drill inserts 1 each having a size of 5, 2/3 were produced, mounted on the drill tool body T, and cut under the following conditions.

[0033] Then, the synthetic force was measured by a known method to confirm the synthetic force direction N, and the state of the chips cut by the outer blade insert 7 was visually observed.

The results were as follows.

[0035] From the above results, in the drill insert 1, the width w of the protruding portion 6 is 2/5 to 3 / with respect to the length l of one side thereof.
It has been found that a range of 5 is preferable.

[0036]

As described above, the present invention is a drill insert in which a cutting edge is formed on each ridge of an upper surface of a polygonal plate-shaped body, and at least one of the above-mentioned cutting edges is provided. A projecting portion having a pair of corner R portions (4) and (5) is provided on the end side, and a non-projecting portion is provided on the other end side, and a linear cutting edge portion provided at the tip of the projecting portion and the non-projecting portion are provided. The straight line portion and the straight line portion are made non-parallel in a plan view, and the intersections of the straight lines in these linear cutting edge portions are located on the side of the protruding portion, and the pair of corner R portions are curved portions. The angle formed by continuous straight lines is 60 °
105 °, and one of the corners R is continuous with the cutting edge adjacent to the cutting edge on which the non-protruding portion is formed,
The ratio of the width of the protrusion to the length of the side on which the protrusion is formed is 2/5 to 3/5, and the inner diameter of the tip of the tool body having a substantially cylindrical shape. In a throw-away drill in which drill inserts are detachably attached to the outer diameter side and the outer diameter side, the drill insert is arranged on the outer diameter side so that the cutting edge having the protruding portion is on the tip side of the tool body. Along with
The linear cutting edge at the tip of the protruding portion inclines toward the rear end side of the tool body from the inner diameter side to the outer diameter side of the tool body, and the linear cutting edge portion of the non-projection portion is the tool body. The throw-away drill, which is characterized in that it is inclined from the outer diameter side to the inner diameter side toward the rear end side of the tool body, has the following excellent effects. That is, the direction of the combined force of the radial load of the inner blade insert and the outer blade insert is from the center axis of the tool body to the outer blade insert side, which allows the outer blade insert and the hole wall to contact when the drill tool is removed from the workpiece. A good finished surface can be processed without doing.

Further, according to the present invention, among the corner R portions forming the protruding portion of the outer blade insert facing the hole bottom, the corner R portion on the inner diameter side divides the chips from the hole bottom side, so that the outer blade insert side Chips are cut into small pieces and ejected,
It also has the effect of.

[Brief description of drawings]

FIG. 1 is a plan view of a drill insert of the present invention.

2 is a side view of a throw-away drill equipped with the drill insert of FIG. 1. FIG.

3 is a side view of only the drill insert of the throw-away drill of FIG. 2. FIG.

4 is a bottom plan view of only the drill insert of the throw-away drill of FIG. 1. FIG.

FIG. 5 is a layout view showing a configuration of a drill insert and a throw-away drill according to another embodiment, in which an upper side is a side layout of only a drill insert of the throw-away drill,
The bottom side shows the bottom surface arrangement.

FIG. 6 is a layout diagram corresponding to FIG. 5, showing the configurations of a drill insert and a throw-away drill according to another embodiment of the present invention.

FIG. 7 is a layout diagram corresponding to FIG. 5 showing the configurations of a drill insert and a throw-away drill according to another embodiment of the present invention.

FIG. 8 is a layout diagram corresponding to FIG. 5, showing the configurations of a drill insert and a throw-away drill according to another embodiment of the present invention.

FIG. 9 is a layout diagram corresponding to FIG. 5, showing the configurations of a drill insert and a throw-away drill according to another embodiment of the present invention.

FIG. 10 is a layout view corresponding to FIG. 5 showing the configurations of a drill insert and a throw-away drill according to another embodiment of the present invention.

FIG. 11 is a view showing a shape and an arrangement of a configuration of a conventional drill insert and a throw-away drill,
(A) is a side surface layout drawing of only a drill insert of a throw-away drill, (b) is a bottom surface layout drawing.

[Explanation of symbols]

1 ... Drill insert, 2 ... Top surface, 3 ... Main cutting edge,
4, 5 ・ ・ Corner R part, 6 ・ ・ Projection part, 7 ・ ・ Outer blade insert, 8 ・ ・ Inner blade insert, 9 ・ ・ Bottom cutting edge, T ・
・ Tool body, T1 ・ ・ Center axis, T2 ・ ・ Side face, N ・ ・ Synthetic force direction, l ・ ・ Length, w ・ ・ Width

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23B 51/00

Claims (2)

(57) [Claims] 1. A drill insert in which a cutting edge is formed on each ridge of an upper surface of a polygonal plate-like body,
In at least one of the cutting blades, a linear portion provided with a protruding portion having a pair of corner R portions (4) and (5) on one end side and a non-projecting portion on the other end side and provided at the tip of the protruding portion The cutting edge portion and the linear portion of the non-projecting portion are made non-parallel in a plan view, and the intersections of the straight lines in these linear cutting blade portions are located on the side of the projecting portion , the pair of The corner R part of the
The angle formed by the continuing straight lines is 60 ° to 105 °, and
One of the corners R has the non-protruding portion
Continuing to the cutting edge adjacent to the cutting edge, the protrusion was formed
The ratio of the width of the protrusion to the side length is 2/5 to 3/5.
Drill insert, characterized in that it. 2. A throw-away drill in which a drill insert is detachably attached to the inner diameter side and the outer diameter side of the tip of a tool body having a substantially cylindrical shape, and the drill insert according to claim 1 is used. The cutting edge formed is arranged on the outer diameter side so as to be the tip side of the tool body, and the linear cutting edge of the tip of the protrusion is of the tool body.
Inclined from the inner diameter side to the outer diameter side toward the rear end side of the tool body
And the straight cutting edge portion of the non-protruding portion is the tool body.
From the outer diameter side toward the inside diameter side throwaway drill, characterized in that the inclined <br/> obliquely to the rear end side of the tool body of.