JP2006007393A - Throwaway drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a throw-away drill having high strength and excellent positioning accuracy.
SOLUTION: A throw-away tip 4 provided with two cutting edges 12 at a tip end is detachably mounted in a tip recess 3 of a holder 2, and the holder 2 has a locking wall surface formed on an inner wall surface. 6, a screw bottom 7 formed on the other inner wall surface side, and a support bottom surface including a plurality of inclined surfaces 10 at least partially inclined so as to be symmetrical with respect to the rotation shaft 11 at the bottom of the tip recess 3. 9, the chip 4 includes a first side surface 13 that abuts the locking wall surface 6 of the holder 2 on at least one of the main side surfaces, a second side surface 15 in which a recess 14 is formed on the other main side surface, and a support And a supported bottom surface 16 having a plurality of inclined surfaces 17 at least partially inclined so as to be symmetric with respect to the rotating shaft 11 so as to come into contact with the bottom surface 9, and screw members from the screw holes 7 of the holder 2. 5 is screwed into the recess 14 of the chip 4 The tip 4 abuts and the chip 4 is pressed and fixed in the tip recess 3.
[Selection] Figure 1

Description

  The present invention relates to a throw-away drill in which a throw-away tip having a rotation axis common to a holder tool main body is detachably mounted.

  Conventionally, as a throw-away drill in which a throw-away tip having a rotation axis common to the holder tool body is detachably mounted, a plate-shaped throw-away tip having a through hole is inserted between the wall surfaces of the holder tip, and the side surface of the holder In other words, a configuration is known in which a screw is fastened with a screw (for example, see Patent Document 1).

Further, as disclosed in Patent Document 2, a cylindrical shaft portion and a wall surface inclined with respect to the rotation shaft are formed on a plate-shaped throwaway tip, and a screw is pressed against the throwaway tip from the holder side surface in the radial direction. Further, a configuration for fixing in the axial direction is also known.
JP 2003-175413 A JP-T-2004-501785

  However, in the configuration as disclosed in Patent Document 1, the through-hole is formed in the throw-away tip, so that the strength of the throw-away tip itself is low, especially in machining with high impact such as intermittent machining. There was a problem that sometimes the throw-away tip was broken and the holder or product was damaged.

  Further, in the configuration as disclosed in Patent Document 2, in order to accurately position the throw-away tip, the cylindrical shaft portion on the side surface of the throw-away tip must be processed with high accuracy. There was a problem that the cost was extremely high.

  The present invention has been made to solve the above-described problems of the prior art, and is positioned with high strength in a throw-away drill in which a throw-away tip having a rotation axis common to the holder tool body is detachably mounted. The purpose is to provide a throw-away drill with excellent accuracy at low cost.

  In order to solve the above-mentioned problems, a throw-away drill according to the present invention has a substantially plate-like throw provided with two cutting edges at the tip and two main side surfaces following the cutting edge and a chip discharge groove adjacent to the cutting edge. The away tip is detachably mounted in a tip recess provided in a holder having a rotation axis common to the throw-away tip, and is sandwiched between two inner wall surfaces facing each other following the tip recess of the holder. A throwaway drill that is fixed in a closed state, wherein the holder includes a locking wall surface formed on one inner wall surface, a screw hole formed on the other inner wall surface, and a bottom portion of the tip recess And a support bottom surface having a plurality of inclined surfaces inclined at least partially so as to be symmetric with respect to the rotation axis, and the throw-away tip is associated with the holder on at least one of the main side surfaces. Stop wall At least a part is inclined so as to be symmetric with respect to the rotation axis so as to come into contact with the first side surface to be in contact with, the second side surface with the depression formed on the other main side surface, and the support bottom surface of the holder And a supported bottom surface having a plurality of inclined surfaces, and a screw member is screwed into the screw hole of the holder, and the tip of the screw member is brought into contact with the hollow portion of the throw-away tip. Thus, the throw-away tip is pressed and fixed in the concave portion at the tip of the holder.

  According to such a configuration, the throw-away tip can be pressed and fixed to the holder without providing a through-hole in the throw-away tip body, so that the throw-away tip may be damaged even in a process with a large impact such as intermittent machining. In addition, it is possible to perform stable processing with high reliability, and even when applied to a small-diameter throw-away drill, the strength of the holder and the throw-away tip can be maintained and the rigidity can be maintained. In addition, the throw-away tip is positioned so that each rotation axis, that is, the center position is coincident with the inclined surface symmetrical to the rotation axis formed on the support bottom surface of the holder in addition to the recess, so that the center position is coincident. Accuracy is improved and high-precision drilling is possible.

  In addition, the fact that the axis of the screw hole is inclined toward the holder rear end side toward the rotation axis can be fixed so that the supported bottom surface of the throw-away tip is pressed against the support bottom surface of the holder. Since the tip is securely abutted against and fixed to the holder, it is desirable in that the positioning stability of the throw-away tip is improved and the throw-away tip can be prevented from coming out of the holder.

  Further, when viewed in a longitudinal section, the screw hole is screwed in a direction in which the angle α formed by the axis of the screw hole and the rotation axis is in the range of 84 degrees to 88 degrees, the pressing force in the radial direction, the axial direction It is desirable in terms of a good balance between the pressing force to the tip and the depth of the hollow portion of the throw-away tip so that the strength of the tip can be improved.

  In addition, when the holder tip is viewed, the axis of the screw hole and the virtual extension intersection line of the inclined surfaces symmetrical to the rotation axis on the support bottom surface of the holder are parallel to each other. Since the pressing force in the direction can be generated in a balanced manner on the two inclined surfaces, it is desirable in that the throw away tip is firmly pressed and fixed to the locking wall surface and the support bottom surface of the holder without being attached while being inclined. .

  In addition, the surface of the hollow portion with which the screw member comes into contact is flat, so that the tip of the screw member and the hollow portion can be reliably brought into contact with each other, and the throwaway tip can be fixed to the holder. It is desirable in that it can be made more stable.

  Further, an intermediate surface substantially parallel to the rotation axis is provided between the first side surface and the second side surface of the chip discharge groove, so that the holder of the throwaway tip is engaged. Since it is possible to increase the area abutted against the stop wall, it is desirable in that the restraint force of the chip can be increased and the repeatability of positioning is more stable.

  According to the throw-away drill of the present invention, the throw-away tip can be pressed and fixed to the holder without providing a through-hole in the throw-away tip body. In addition to being able to perform stable processing with high reliability without damage, even when applied to a small-diameter throw-away drill, the strength of the holder and the throw-away tip can be maintained and the rigidity can be maintained. In addition, since the throw-away tip is positioned so that each rotation axis, that is, the center position coincides with a plurality of inclined surfaces symmetrical to the rotation axis formed on the support bottom surface of the holder in addition to the hollow portion, as a guide, Repeated mounting accuracy is improved, and highly accurate drilling is possible.

  A preferred embodiment of the throw-away drill according to the present invention will be described with reference to the accompanying drawings.

  1 is an exploded perspective view of a main part of the tip of the throw-away drill according to the first embodiment of the present invention, FIG. 2 is a (a) front view of the holder of FIG. 3) is a front side perspective view, FIG. 3 is (a) a main side view, (b) a side view in the direction of arrow B, (c) a rear end side perspective view, and FIG. 4 is a second view of the present invention. FIG. 5A is a front view of the holder according to the embodiment, FIG. 5B is a side view of the C direction arrow, FIG. 5A is a main side view of the throw-away tip corresponding to the holder of FIG. FIG. 6 is a perspective view of the holder according to the third embodiment of the present invention. FIG. 6 is a perspective view of the front end of the holder according to the third embodiment of the present invention. It is (a) main side view of a corresponding throwaway tip, (b) rear end side perspective view.

  In FIG. 1, a throw-away drill (hereinafter abbreviated as a drill) 1 according to a first embodiment of the present invention has two cutting edges 12 at a tip portion and a chip discharge groove adjacent to the cutting edge 12 at a main side portion. A generally plate-shaped throw-away tip (hereinafter abbreviated as “chip”) 4 provided with 8 is detachably attached to a tip recess 3 of a holder 2 having a rotating shaft 11 in common with the tip 4. It is fixed in a state of being sandwiched between two inner wall surfaces facing each other following the tip recess.

  The holder 2 includes a locking wall surface 3 formed on one of the opposing inner wall surfaces of the tip recess 3, a screw hole 7 formed so as to penetrate from the other inner wall surface to the outer peripheral surface, and the tip recess 3 is provided with a support bottom surface 9 having a plurality of inclined surfaces 10 that are inclined so as to be symmetric with respect to the rotating shaft 11, and the chip 4 is provided on at least one of the main side surfaces of the holder 2. The rotating shaft 11 is brought into contact with the first side surface 13 that is brought into contact with the locking wall surface 6 and locked, the second side surface 15 having a recess 14 formed on the other side, and the support bottom surface 9 of the holder 2. And a supported bottom surface 16 having a plurality of inclined surfaces 17 which are inclined so as to be symmetrical with respect to each other, and a recess portion of the chip 4 by a screw member 5 screwed into the screw hole 7 of the holder 2. 14 and the tip 4 is brought into contact with the tip of the screw member 5 It is configured to be pressed and fixed to the holder 2 of the tip recess 3.

Here, the depth t ₁ of the hollow portion 14 is 10 to 30% with respect to the thickness t ₂ of the center portion of the chip 4 in terms of securing the strength of the chip 4 and the fixing accuracy of the screw member 5. A particularly desirable range is 15 to 20%.

  In particular, as shown in FIGS. 1 and 3, the chip 4 is formed on the side surface of the chip 4 without providing a clamp hole or a through hole for fixing the chip 4 to the holder 2 in the chip 4 itself. Since the recessed portion 14 can be fixed to the holder 2 by pressing with the screw member 5, the chip 4 is not damaged even in the processing with a large impact such as intermittent processing, so that reliable and stable processing can be performed. While being able to be performed, even when applied to a small-diameter drill, the strength of the holder and the tip is not lowered and high rigidity can be maintained. Further, as shown in FIG. 3A, the lower surface of the chip 4 is a supported bottom surface 16 having two inclined surfaces 17 and 17 which are inclined so as to be symmetric with respect to the rotating shaft 11, The supported bottom surface 16 is in contact with the support bottom surface 9 formed on the bottom of the tip recess 3 of the holder 2 shown in FIGS. 1 and 2, and the holder 2 and the chip 4 are rotated using the inclined surface 10 of the support bottom surface 9 as a guide. Since the shaft, that is, the center position is positioned so as to coincide with each other, repeated mounting accuracy is improved, and high-precision drilling is possible.

  Further, as shown in FIG. 2B, the axis 18 of the screw hole 7 is inclined toward the rear end side of the holder 2 toward the central axis of the holder 2, that is, the rotating shaft 11. The supporting bottom surface 9 and the supported bottom surface 16 of the chip 4 can be surely brought into contact with each other, so that positioning stability can be improved and the chip 4 can be prevented from coming out of the holder 2.

  Incidentally, as shown in FIG. 2, by screwing the screw hole 7 so that the angle α formed by the axis 18 of the screw hole 7 and the rotary shaft 11 is in the range of 84 degrees to 88 degrees, the radial direction is achieved. Pressing force (the pressing force between the locking wall surface 6 of the holder 2 and the first side surface 13 of the chip 4) and the pressing force in the axial direction (the pressing force between the supporting bottom surface 9 of the holder 2 and the supported bottom surface 16 of the chip 4). Pressure) acts in a balanced manner, so that the mounting stability of the chip 4 to the holder 2 is further increased. Furthermore, since it is not necessary to form the recess 14 of the chip 4 more deeply than necessary, it is desirable in that the rigidity of the chip 4 itself can be maintained.

  Further, as shown in FIG. 4A, which is the second embodiment of the present invention, a virtual extended intersection line 19 between inclined surfaces 10 symmetrical to the rotation axis 11 on the support bottom surface 9 of the holder 2 and The support bottom surface 9 (inclined surface 10) and the supported bottom surface 16 (inclined surface 17) are arranged so that the axis 18 of the screw hole 7 is parallel (see FIGS. 4 and 5). Since the pressing force in the direction of the rotation axis can be generated in a balanced manner on the two inclined surfaces, the chip 4 is pressed and fixed to the locking wall surface 6 and the support bottom surface 9 of the holder 2 without being attached while the chip 4 is inclined. it can. Incidentally, the axial line 18 of the screw hole 7 is arranged so as to be directed toward the center of the holder 2, so that the mounting balance in the radial direction of the chip 4 is evenly distributed on the left and right. This is desirable in terms of stable mounting.

  It should be noted that the surface of the recess 14 on which the screw member 5 abuts is flat, so that the tip of the screw member 5 and the recess 14 can be reliably abutted with high positional accuracy. It is desirable in that the fixation to 2 can be made more stable.

  Further, as shown in FIGS. 3 and 5, the chip discharge groove 8 includes a first side surface 13 and a second side surface 15, and an intermediate surface 21 substantially parallel to the rotation axis. Thus, since the first side surface 13 serving as the restraint surface can be provided in a wider area, the restraint force increases and the positioning repeatability is further stabilized.

  As shown in FIGS. 3 and 5, forming the chamfered portion 20 between the two supported bottom surfaces 16 of the chip 4 ensures the support bottom surface 9 of the holder and the supported bottom surface 16 of the chip 4. It is preferable in that it can be brought into contact with each other and the rigidity of the chip 4 itself can be maintained. The chamfered shape may be flat or convex curved toward the rear end of the chip 4.

  As a third embodiment of the present invention, FIG. 6 and FIG. 7 show irregularities in which the support bottom surface 9 of the holder 2 and the supported bottom surface 16 of the chip 4 have a large number of inclined surfaces 22 and 23 connected in a wave shape. The example which is a structure of a shape is shown. By adopting such a configuration, the constraint of the chip 4 becomes stronger, and stable machining can be continued without moving the chip 4 even in cutting with a particularly large impact.

  Note that the chip 4 in this embodiment has an asymmetric shape with respect to the so-called rotating shaft 11 having the first side surface 13 on one of the main side surfaces and the recess 14 on the other side. The one side surface 13 and the hollow portion 14 may be arranged so that the first side surface 13 and the second side surface 15 are rotationally symmetric with respect to the rotation shaft 11. In this case, since the recesses 14 are provided on both sides of the chip 4, the attachment to the holder 2 may be either front or back, and workability is improved.

It is a tip principal part disassembled perspective view of the throw away drill by a first embodiment of the present invention. 2A is a front view of the holder of FIG. 1, FIG. 2B is a side view of the direction of the arrow A, and FIG. It is (a) main side view of the throw away tip of FIG. 1, (b) B direction arrow side view, (c) Rear end side perspective view. It is (a) tip view of the holder by 2nd embodiment of this invention, (b) C direction arrow side view. It is (a) main side view of the throw away tip corresponding to the holder of FIG. 4, (b) D direction arrow side view, (c) rear end side perspective view. It is (a) tip view of the holder by 3rd embodiment of this invention, (b) tip side perspective view. It is the (a) main side view of the throw away tip corresponding to the holder of FIG. 6, (b) the rear end side perspective view.

Explanation of symbols

1 Throw away drill (drill)
2 Holder 3 Tip recess 4 Throw away tip (chip)
5 Screw member 6 Locking wall surface 7 Screw hole 8 Chip discharge groove 9 Support bottom surface 10, 17, 22, 23 of holder Inclined surface 11 Rotating shaft 12 Cutting edge 13 First side surface 14 Recessed portion 15 Second side surface 16 Supported bottom surface 18 Axis 19 of screw hole 7 Virtually extending intersection line 20 of inclined surface Chamfered portion 21 Intermediate surface α Angle formed by axis of screw hole and rotation axis t ₁ Depth of recessed portion t ₂ Thickness of center portion of chip 4

Claims (6)

Two cutting edges at the tip, and a substantially plate-shaped throwaway tip having a chip discharge groove adjacent to the cutting edge on two main side surfaces following the cutting edge, and a rotation axis common to the throwaway tip In a throw-away drill that is detachably mounted in a tip recess provided in a holder having, and fixed in a state sandwiched between two inner wall surfaces facing each other following the tip recess of the holder,
The holder includes at least one locking wall formed on one inner wall surface, a screw hole formed on the other inner wall surface, and a bottom portion of the tip recess so as to be symmetrical with respect to the rotation axis. A support bottom surface having a plurality of inclined surfaces formed by inclined portions,
The throw-away tip includes a first side surface that abuts a locking wall surface of the holder on at least one of the main side surfaces, a second side surface in which a recess is formed on the other main side surface, and a support bottom surface of the holder And a supported bottom surface having a plurality of inclined surfaces that are inclined at least partially so as to be symmetric with respect to the rotation axis so as to abut.
The screw member is screwed into the screw hole of the holder and the tip of the screw member is brought into contact with the recess of the throw-away tip, thereby pressing and fixing the throw-away tip into the tip recess of the holder. Characteristic throw-away drill. The throw-away drill according to claim 1, wherein an axis of the screw hole is inclined toward a holder rear end side toward the rotation axis. 3. The throw-away drill according to claim 2, wherein the screw hole is screwed in a direction in which an angle α formed by the axis of the screw hole and the rotation axis is in a range of 84 degrees to 88 degrees in a longitudinal sectional view. . The axis of the screw hole and a virtual extension intersection line of inclined surfaces symmetrical to the rotation axis on the support bottom surface of the holder are parallel to each other when viewed from the front end of the holder. Any throw-away drill. The throw-away drill according to any one of claims 1 to 4, wherein a surface of the hollow portion with which the screw member abuts is flat. The throw-away drill according to any one of claims 1 to 5, wherein an intermediate surface substantially parallel to the rotation axis is provided between the first side surface and the second side surface of the chip discharge groove. .

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