JPH0671681B2 - Throw-away type drilling tool - Google Patents

Description

TECHNICAL FIELD The present invention relates to a throwaway type drilling tool suitable for use in various drilling processes such as drills and boring tools.

[Prior Art] FIGS. 16 and 17 show a conventional throwaway type drill which is a kind of the above-mentioned throwaway type drilling tool, and reference numeral 1 in the drawing denotes a drill body (tool body).

The drill body 1 has a substantially cylindrical appearance, and a chip discharge groove 2 is formed along the axial direction on the outer periphery of the tip end portion of the drill body. 3 is formed. And this chip 3
A diamond-shaped plate-shaped throwaway chip (hereinafter referred to as “chip”) 4 made of cemented carbide or the like is clamped by arranging a cutting edge 5 formed on a ridge portion thereof on the tip side of the drill body 1. It is detachably attached with a screw 6.

Here, in this chip 4, the cutting edge 5 is located along the radial direction from the axis O of the drill body 1, and the axis O
The upper end 5a is mounted so as to be located closer to the tip side of the drill body 1 than the end 5b on the outer peripheral side.

Then, in the above-mentioned conventional throwaway drill having the above-described configuration, either one of the drill and the work piece is rotated and is sent in the direction of the axis O thereof, so that the cutting blade 5 cuts the work piece. A hole whose radius is the entire length of the cutting edge 5 is processed.

[Problems to be Solved by the Invention] However, in the above-described conventional throw-away drill, when the end 5a of the cutting edge 5 is positioned beyond the axis O of the drill book 1, the tip of the drill body 1 The portion beyond the axis O projecting to the side scrapes the surface of the work piece and cannot be punched. If the end 5a does not reach the axis O, a cylindrical core which is not cut is formed between the end 5a and the workpiece.

Therefore, the cutting edge 5 must be arranged along the radial direction of the drill body 1 with its one end 5a positioned on the axis O. Therefore, as shown in FIG. 17, the thickness dimension of the chip 4 cannot be increased, and further, the back metal L cannot be sufficiently taken from the drill main body 1, resulting in poor tool rigidity. there were.

In addition, since there is only one hole inside diameter that can be processed by one drill, it is necessary to prepare drills having different chip sizes as many as the inside diameter of the hole to be processed, which is extremely uneconomical. It was

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a throwaway type drilling tool capable of taking a large back metal on the tool body side and having excellent tool rigidity. is there.

[Means for Solving the Problems] The throwaway type drilling tool of the present invention has a tip end of the tool body, a corner portion of the top surface located on the center side of the tool body, from the center portion of the top surface to the tip of the corner portion. On the cutting edge where the axis of the hole to be machined is inclined along the inclined surface, or on the inclined surface side from this cutting edge. It is installed so that it is located at.

[Embodiment] FIGS. 1 to 5 show an example applied to a throwaway type drill as a first example of the throwaway type drilling tool of the present invention, and are shown in FIG. 16 and FIG. The same parts as those in FIG.

1 to 5, in the throwaway type drill of this example, a diamond plate-shaped chip 10 is detachably attached to a chip seat 3 of a drill body (tool body) 1 by a clamp screw 6.

In this chip 10, a corner portion of the upper surface 11 located on the side of the axis O of the drill body 1 is provided with an inclined surface 12 in which the thickness between the upper and lower surfaces gradually decreases from the central portion of the upper surface 11 toward the tip of the corner portion. Has been formed. Therefore, the cutting edge 13 formed on the ridgeline portion of the upper surface 11 on the tip side of the drill body 1 is formed so as to be inclined from the upper surface 11 toward the lower surface side at the corner portion.

As shown in FIG. 4, the chip 10 is arranged such that the axis O of the drill body 1 is located on the cutting edge 13 inclined by the inclined surface 12 or on the inclined surface 12 side of the cutting edge 13 and the negative It is attached with a rake angle α. Therefore, the chip 10 is mounted upright by the dimension a from the axis O to the upper surface 11. Incidentally, reference numeral 14 in the drawing denotes an oil hole for supplying cutting oil from the base end side of the drill body 1 to the vicinity of the cutting edge 13.

Next, the operation of the above-mentioned throwaway type drill having the above-described configuration will be described in the case of rotating the workpiece to perform drilling.

First, the axis O of the throwaway type drill is aligned with the rotation axis of the workpiece, and the throwaway type drill is brought toward the workpiece in the direction of the axis O. Then, the axis O of the throwaway type drill is applied to the work piece.
A hole having a radius from the end to the end 13b of the cutting edge 13 is machined.

In this case, as shown in FIG. 5, as a result of forming the inclined surface 12 at the corner portion of the chip 10, the portion of the cutting edge 13 inclined by the inclined surface 12 is different from the straight portion along the upper surface 11. Since it is inclined from the outer peripheral side of the drill body 1 toward the center side toward the base end side of the drill body 1 at an angle θ, the part of the center side end part 13a beyond the axis O contacts the workpiece. Never.

In addition, this throw away type drill can also perform drilling with different inner diameters.

That is, as shown in FIG. 6, the axis O of the throwaway drill is moved in the direction of the axis O with a predetermined distance X from the axis O ₁ of the workpiece. Then, a hole having a radius from the axis of rotation O ₁ to the end 13b of the cutting edge 13 is machined in the workpiece. Therefore, a hole having an inner diameter larger than that of the hole formed when the axes O and O ₁ are aligned with each other by a dimension of 2X is formed. In this drilling, a small columnar core 15 having a radius of the distance from the axis O ₁ to the cutting edge 13 is formed in the vicinity of the axis O ₁ of rotation of the workpiece. Then, the core 15 grows in accordance with the feed of the throwaway type drill, and then comes into contact with the inclined surface 12 of the chip 10 and is threaded.

As described above, in the throw-away drill of this example, the inclined surface 12 is formed at the corner portion of the upper surface 11 of the chip 10, so that the chip 10 can be mounted more upright than the conventional one. Therefore, a back metal having a large dimension L ₁ can be secured on the drill body 1 side, and high tool rigidity can be obtained.

Moreover, since the inclined portion of the cutting edge 13 is inclined toward the base end side of the drill body 1 as a result of forming the inclined surface 12, the center side end portion 13a of the cutting edge 13 is extended to a position beyond the axis O. Therefore, as described above, it is possible to obtain an excellent effect that it is possible to perform drilling with different inner diameters by using one drill. Further, so-called fine boring or the like can be performed by moving the axis O slightly from the rotation axis O ₁ of the workpiece to expose the inner diameter of the hole again after the hole has been drilled.

[Other Embodiments] FIGS. 7 to 11 show a throwaway drill which is a second embodiment of the throwaway drilling tool of the present invention.

In the throw-away type drill of this example, the thickness between the upper and lower surfaces of the upper surface 21 of the chip 20 mounted on the drill body 1 from the central portion of the upper surface 21 toward the corner is closer to the center side corner portion. An inclined surface 22 that becomes gradually thinner is inclined, and a step portion 23 that is substantially parallel to the upper surface 21 is formed between the inclined surface 22 and the tip of the corner portion. The same inclined surface 22 and the same stepped portion 23 are also formed at the corner portion that is diagonally opposed to this corner portion.

Also, this chip 20 is arranged such that the axis O of the drill body 1 is located on the cutting edge 24 inclined by the inclined surface 22 or closer to the inclined surface 22 side than the cutting edge 24, and the negative rake angle α.
Is attached.

As a result, also in the throwaway drill of this example, as shown in FIG. 11, the axis O of the drill is separated from the rotation axis O ₁ of the workpiece by a predetermined dimension X to machine holes having different inner diameters. be able to.

Therefore, even in the above throwaway drill,
It is possible to obtain the same effects as those shown in the first embodiment, and further, in this throwaway type drill, a step portion 23 is formed between the inclined surface 22 and the tip of the corner portion. Therefore, the strength of the chip 20 at the tip of the corner can be prevented from being reduced, and the inclination angle of the inclined surface 22 can be made large, so that the cutting performance of the core can be excellent. Further, since the inclined surface 22 and the step portion 23 are formed symmetrically at the corner portions of the chip 20 which are diagonally opposed to each other, the portion which is further symmetrical by rotating the chip 20 by 180 °. Can be used for drilling and is therefore economically efficient.

In the description of the first and second embodiments, when machining holes having different inner diameters, a gap is formed between the cutting edges 13 and 24 and the rotation axis O ₁ to form a core. As described above, the axis O is separated from the rotation axis O ₁ of the workpiece, but the present invention is not limited to this, and the axis O may extend along the end 13a of the cutting blade 13 that is inclined as shown in FIG. 12, for example. It is also possible to perform the drilling process by separating the cores so that the core is not formed.

As shown in FIG. 13, an inclined surface 26, which is gentler than the inclined surface 22, is formed between the inclined surface 22 and the corner tip, and the axis O is separated along the inclined cutting edge 24a of this portion. You may let me.

Further, the shape of the chip to be mounted is not limited to the rhombus, and as shown in FIGS. 14 and 15, the trapezoidal chip 30 is an upper surface 31 located on the center side of the drill body 1.
It is also possible to attach the one having the inclined surface 32 in which the thickness between the upper and lower surfaces is gradually reduced from the central portion thereof toward the tip end side of the corner portion.

[Advantages of the Invention] As described above, the throwaway type drilling tool of the present invention has a tip portion of the tool body, a corner portion of the upper surface located on the center side of the tool body, from the center portion to the tip portion side of the corner portion. Position the chip on which an inclined surface is formed such that the thickness between the upper and lower surfaces gradually decreases toward the cutting edge where the axis of the hole to be processed is inclined along the inclined surface or on the inclined surface side of this cutting edge. It was installed so that

Therefore, according to this throw-away drilling tool, the chip can be mounted in a raised manner, so that a large back metal can be secured on the tool body side, and as a result, high tool rigidity can be obtained. Moreover, as a result of extending the cutting edge to a position beyond the axis, by separating the axis from the axis of the hole to be processed, it is possible to perform drilling of different inner diameters with one tool.

Furthermore, after performing the drilling on one end, by slightly moving the axis from the rotation axis of the workpiece to expose the inner diameter of the hole again, so-called fine boring can be performed, which is also an excellent effect. be able to.

[Brief description of drawings]

1 to 5 show a first embodiment of a throwaway type drilling tool according to the present invention. FIG. 1 is a plan view, FIG. 2 is a front view, and FIG. 3 is a side face on the base end side. Fig. 4 is a side view of the tip side, Fig. 5 is an enlarged plan view of the tip portion, Fig. 6 is a diagram showing an example of drilling with the above drilling tool, and Figs.
FIG. 10 shows a second embodiment of the present invention. FIG. 7 is a plan view, FIG. 8 is a front view, FIG. 9 is a side view on the tip side, and FIG.
FIG. 11 is a view taken along the line AA in FIG. 7, FIG. 11 is a view showing an example of drilling with the above drilling tool, and FIGS. 12 and 13 are views showing examples of mounting other chips, respectively. Figures 14 and
FIG. 15 shows a third embodiment of the present invention. FIG. 14 is a plan view, FIG. 15 is a view taken along the line BB of FIG. 14, and FIGS. 16 and 17 are conventional throwaway type. FIG. 16 is a plan view of the tip portion, and FIG. 17 is a side view on the tip side, showing a drill. 1 …… Drill body (tool body), 3 …… Chip seat, 10,20,30 …… Throw-away tip, 11,21,31 …… Top surface, 12,22,26,32 …… Sloping surface, 13, 24 …… Cutting edge, O, O ₁ …… Axis.

Claims (1)

[Claims] 1. A throwaway type drilling tool in which a cutting edge having a throwaway tip formed on a ridge portion of its upper surface is attached to the tip of the tool body at the tip side of the tool body. In the corner portion of the upper surface of the throwaway chip located on the center side of the tool body, an inclined surface is formed in which the thickness between the upper and lower surfaces gradually decreases from the center of the upper surface toward the tip of the corner portion. The throwaway chip is mounted such that the axis of the hole to be processed is located on the cutting edge that is inclined along the inclined surface or on the inclined surface from the cutting edge. Dawn tool.