JP2006123078A - Throw-away drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throw-away drill superior in durability, and superior in repetitive positioning accuracy. <P>SOLUTION: This throw-away drill 1 is formed by sandwiching and fixing a substantially plate-like throw-away tip 3 having two cutting edges 4 in a tip part in a tip recessed part 8 of a holder 2 having a common rotary shaft 7. The holder 2 has a first wall surface 9a for respectively forming two inner wall surfaces 9 of a part of a cylindrical concave curved surface coaxial with the rotary shaft 7 and a second wall surface 9b formed of a recess-projection surface extending in substantially parallel to the rotary shaft 7. The throw-away tip 3 has the rotary shaft 7 for respectively fitting two main side surfaces 5 to the first wall surface 9a of the holder 2, a first side surface 5a formed of a part of the coaxial cylindrical convex curved surface, and a second side surface 5b formed of the recess-projection surface extending in substantially parallel to the rotary shaft 7 to be fitted to the second wall surface 9b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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.

  2. Description of the Related Art Conventionally, as a throw-away drill in which a throw-away tip having a rotation axis common to a holder tool main body is detachably mounted, a configuration is known in which the throw-away tip is fixed using elastic deformation of a holder (for example, a patent Reference 1).

In addition, a configuration is also known in which a cylindrical shaft portion and a wall surface inclined with respect to the rotation shaft are formed on the throw-away tip as disclosed in Patent Document 2, and a screw is pressed and fixed from the side of the holder. .
JP-T-2002-501441 JP-T-2004-501785

  However, in the configuration using the elastic deformation of the holder as disclosed in Patent Document 1, the elastic force of the holder weakens as the throw-away tip is repeatedly replaced, and the throw-away tip is removed from the tool body during processing. There was a problem of falling off or being damaged.

  In the configuration disclosed in Patent Document 2, since the radial positioning is performed only by the cylindrical shaft portion of the throw-away tip and the bearing of the holder, if a large cutting torque is applied during processing, the shaft portion and the bearing are A gap will occur between them. As a result, there is a problem that the throw-away tip moves from the tool main body due to movement of the throw-away tip and deterioration of the machining accuracy, or further increase in the gap.

  The present invention has been made to solve the above-described problems of the prior art, and is excellent in durability in a throw-away drill in which a throw-away tip having a rotation axis common to a holder tool body is detachably mounted. At the same time, the object is to provide a reliable throw-away drill that can maintain machining accuracy for a long time.

  In order to solve the above-mentioned problem, the throw-away drill of the present invention has a substantially plate-like shape having two cutting edges at the tip, two main side surfaces following the cutting edge, and two chip discharge grooves adjacent to the cutting edge. The throwaway tip is detachably mounted in a tip recess provided in a holder having a rotation axis common to the throwaway tip, and between the two inner wall surfaces facing each other following the tip recess of the holder. In the throw-away drill that is sandwiched and fixed, the holder includes a first wall surface formed by a part of a cylindrical concave curved surface that is coaxial with the rotating shaft, and the two inner wall surfaces continuous with the first wall surface. A second wall surface formed by an uneven surface extending substantially parallel to the rotation axis, and a screw hole penetrating from the first wall surface formed on one inner wall surface to the outer periphery of the holder. And The throw-away tip includes a first side surface formed by a part of a cylindrical convex curved surface coaxial with the rotation shaft so that each of the two main side surfaces is fitted to the first wall surface of the holder; And a second side surface formed by an uneven surface extending substantially parallel to the rotation axis so as to be engaged with the second wall surface, and a recess is formed on one of the first side surfaces. The screw member screwed into the screw hole is engaged and pressed and fixed to the first and second wall surfaces of the holder by bringing the tip of the screw member into contact with the recess of the throw-away tip. It is characterized by that.

  According to this configuration, the tip of the throw-away tip is guided by using the first wall surface of the holder formed in a direction facing each other and the first side surface of the throw-away tip configured to be fitted to the first wall surface as a guide. The holder is inserted into the tip recess from the side, and the second wall surface of the holder formed by the concavo-convex surface extending in the tip direction is fitted to the second side surface of the throw-away tip having a shape that fits the second wall surface. Therefore, even if the throw-away tip replacement operation is repeated or a processing load is repeatedly applied, the holder contact surface with the throw-away tip does not deteriorate, and the holder can be kept for a long time. Can be used. That is, it is possible to obtain a reliable throw-away drill with excellent durability, stable machining accuracy.

  Furthermore, since the throw-away tip can be pressed and fixed to the holder without providing a through-hole in the throw-away tip body, the throw-away tip is not damaged even in high impact processing such as intermittent machining. Highly stable machining can be performed, 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 rigidity can be maintained.

  In addition, the throw-away drill of the present invention can accurately position the tip by fitting the second wall surface formed by the uneven surface extending in the tip direction of the holder and the second side surface of the throw-away tip. Thus, each rotational axis, that is, the center position is positioned so as to coincide with each other, so that the repeated mounting accuracy is improved and high-precision drilling is possible.

  In addition, since the axis of the screw hole is inclined toward the holder rear end side toward the rotation axis, the throwaway tip is pressed toward the axial rear end side of the holder, so that it is more stable. It is desirable in that the chip is fixed in the state.

  Furthermore, when the holder tip is viewed, the axial direction of the screw hole is shifted to the chip discharge groove side close to the screw hole with respect to the rotation axis (rotation center of the drill). This is desirable in that the second wall surface and the second side surface on the throw-away tip side are in contact with each other, and the second wall surface and the second side surface on the throw-away tip side are surely brought into contact with each other.

  Further, the second wall surface and the second side surface are inclined toward the rotating shaft side toward the front end side of the holder, that is, the distance between the two first wall surfaces and the two first side surfaces is the front end. When the throw-away tip is about to come out to the tip side of the holder when a large force is generated in the axial direction during processing, the second wall surface and the second side surface are narrowed. The contact with the reverse taper acts as a stopper, which is desirable in that the throwaway tip can be prevented from rattling in the axial direction.

  Furthermore, if the surface of the dent portion on which the screw member abuts is flat, the tip of the screw member and the dent portion can be reliably abutted, and the throwaway tip can be fixed to the holder. It is desirable in that it can be made more stable.

  According to the throw-away drill of the present invention, the throw-away tip with the first wall surface on the holder side and the first side surface on the throw-away tip side formed by a part of the cylindrical concave and convex curved surface coaxial with the rotating shaft as a guide Is inserted into the tip recess, and the second wall surface on the holder side and the second side surface on the throw-away tip side formed by a concavo-convex surface extending substantially parallel to the rotating shaft are fitted, and the screw member The holder can be used stably over a long period of time without deteriorating the restraining force on the contact surface of the holder with the throw-away tip even when the throw-away tip is repeatedly replaced. A reliable throw-away drill with excellent durability and stable machining accuracy can be obtained.

  Further, the throwaway tip can be positioned accurately by fitting the second wall surface formed by the uneven surface extending in the tip direction of the holder and the second side surface of the throwaway tip, so that each rotation axis, that is, the center. Since positioning is performed so that the positions coincide with each other, repeated mounting accuracy is improved, and high-precision drilling is possible.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 3 show an embodiment of the present invention. FIG. 1 is an exploded perspective view of a tip portion of a throwaway drill according to an embodiment of the present invention, and FIG. 2 is (a) a front view of the holder of FIG. Fig. 3 (b) is a side view as viewed in the direction of arrow A, and Fig. 3 is a (a) main side view, (b) is a side view as viewed in the direction of arrow B, and (c) is a front view.

  In FIG. 1, a throw-away drill (hereinafter abbreviated as a drill) 1 according to an embodiment of the present invention has two cutting edges 4 and 4 ′ at a tip portion, and two main side surfaces following the cutting edges 4 and 4 ′. 5 and 5 ′, and a substantially plate-shaped throw-away tip (hereinafter abbreviated as “chip”) 3 provided with chip discharge grooves 6 and 6 ′ adjacent to the cutting blades 4 and 4 ′ are common to the chip 3. The holder 2 having the rotating shaft 7 is detachably mounted in the tip recess 8 and is sandwiched and fixed between the two inner wall surfaces 9 and 9 'facing each other by forming the tip recess 8 of the holder 2. It consists of

  Here, the holder 2 of FIG. 2 constituting the drill 1 of FIG. 1 has a first wall surface 9 a in which each of the two inner wall surfaces 9, 9 ′ is formed by a part of a cylindrical concave curved surface coaxial with the rotating shaft 7. , 9a ′ and the first wall surfaces 9a, 9a ′, and the second wall surfaces 9b, 9b ′ formed by the concavo-convex surfaces extending substantially in parallel with the rotation axis 7 in the distal direction, A screw hole 10 penetrating from the first wall surface 9 a formed on one inner wall surface 9 to the outer periphery of the holder 2 is provided. As shown in FIG. 1, a screw member 12 is screwed into the screw hole 10 when the chip 3 is fixed.

  Next, the tip 3 of FIG. 3 forming the drill 1 of FIG. 1 has the two main side surfaces 5, 5 ′ so that the rotary shaft 7 is fitted to the first wall surfaces 9 a, 9 a ′ of the holder 2. A first side surface 5a, 5a 'formed by a part of a cylindrical convex curved surface coaxial with the first side surface 5a, 5a', and the second side wall surface 9b, 9b 'following the first side surface 5a, 5a'. The second side surface 5b, 5b 'is formed by a concavo-convex surface extending substantially in parallel with the rotating shaft 7 in order to be fitted, and the concave portion 12 is formed on one first side surface 5a. Is formed.

  The tip 3 having such a configuration is inserted from the tip into the tip recess 8 of the holder 2 using the first wall surfaces 9a and 9a ′ of the holder 2 and the first side surfaces 5a and 5a ′ on the tip 3 side as a guide, and further in the tip direction. The screw member 11 is screwed so that the second wall surfaces 9b, 9b 'of the holder 2 having an uneven surface extending in the direction and the second side surfaces 5b, 5b' on the chip 3 side are securely fitted. The chip 3 is fixed to the tip recess 8 of the holder 2 by pressing the recess 12 of the chip 3 with the tip face of 11.

  Here, the concavo-convex surfaces forming the second wall surfaces 9b, 9b ′ and the second side surfaces 5b, 5b ′ of the present invention have a shape in which at least one concave portion and at least one convex portion are continuously formed in the cross section. And a shape in which a beam and a groove extending in the distal direction are formed. Since the chip 3 is locally thinned and the rigidity is not lowered and the chip 3 is firmly restrained by the holder 2, the uneven surface is formed from a so-called serrated shape in which several beams and grooves are formed in parallel. It is desirable to become. Note that the cross-sectional shape of the irregularities may be zigzag or wavy with a curved tip.

  That is, according to the configuration of the present embodiment, the holder is not elastically deformed and the chip is not attached and detached as in the conventional example (see Patent Document 1). Even if the processing load is repeatedly applied, the contact surface of the holder 2 with the chip 3 does not deteriorate. Therefore, since the holder 2 can be used for a long period of time, it is possible to make the drill 1 excellent in durability, stable in processing accuracy, and highly reliable.

  Furthermore, since the chip 3 can be fixed to the holder 2 without providing a through-hole for attaching the holder to the chip 3 body, the rigidity of the chip 3 can be increased, and particularly in machining with a large impact such as intermittent machining. In addition, it is possible to perform highly reliable and stable processing without damaging the tip 3, and even when applied to a small-diameter drill, the strength of the holder and the tip is not lowered and the rigidity can be maintained.

  Further, by fitting the second wall surfaces 9b, 9b ′ of the holder 2 and the second side surfaces 5b, 5b ′ of the chip 3, the positioning accuracy of the chip 3 is increased, and the respective rotating shafts 7, that is, the center positions are matched. Thus, since the holder 2 and the chip 3 are positioned as described above, repeated mounting accuracy is improved and high-precision drilling is possible.

  Further, as shown in FIG. 2B, the axis 10a of the screw hole 10 is inclined toward the holder rear end side toward the rotary shaft 7, that is, the axis 10a of the screw hole 10 and the rotary shaft 7 Since the tip 3 is pressed toward the rear end side in the axial direction of the holder 2, the angle α formed by can be fixed in a more stable state. The desirable range of the angle α is 84 degrees to 88 degrees.

  Further, as shown in FIG. 2A, the axial direction 10 a of the screw hole 10 is shifted to the chip discharge groove 6 side close to the screw hole 10 with respect to the rotary shaft 7 in the holder front view. This increases the force of abutting the second wall surfaces 9b, 9b ′ of the holder 2 and the second side surfaces 5b, 5b ′ of the chip 3 to securely abut both of the chips 3, thereby further restraining the chip 3. It can be stabilized.

Further, as shown in FIGS. 2B and 3B, the second wall surfaces 9b and 9b ′ and the second side surfaces 5b and 5b ′ are inclined toward the rotating shaft 7 toward the distal end side of the holder 2. That is, that the intervals between the second wall surfaces 9b and 9b ′ and the second side surfaces 5b and 5b ′ are narrow on the tip side, the chip 3 is removed from the holder 2 by some processing load during cutting. When a force is generated in the pulling direction, the second wall surfaces 9b, 9b ′ and the second side surfaces 5b, 5b ′ contact each other with a reverse taper to act as a stopper, and the tip 3 is displaced in the axial direction. It will be deterred. Desired range of the inclination angle beta ₂ inclination angle beta ₁ and with respect to the rotation axis of the second side surface with respect to the rotation axis of the second wall is 5 to 10 degrees.

  Further, as shown in FIG. 1 and FIG. 3A, the surface of the recess 12 of the chip 3 on which the screw member 11 is abutted is flat, so that the tip of the screw member 11 and the recess 12 are Since the contact area is increased, the chip 3 can be reliably contacted, and the fixing of the chip 3 to the holder 2 can be made more stable.

  As mentioned above, although embodiment of this invention was illustrated, this invention is not limited to the said embodiment, It cannot be overemphasized that it can be made arbitrary, unless it deviates from the objective of invention.

It is a front-end | tip part disassembled perspective view of the throw away drill by one Embodiment of this invention. It is the (a) front end view of the holder of FIG. 1, and (b) A direction arrow side view. FIG. 2A is a main side view of the throw-away tip of FIG. 1, FIG.

Explanation of symbols

1: Throw away drill (drill)
2: Holder 3: Throw away tip (chip)
4, 4 ': Cutting edge 5, 5': Main side surface 5a, 5a ': First side surface 5b, 5b': Second side surface 6, 6 ': Chip discharge groove 7: Rotating shaft 8: Tip recesses 9, 9' : Inner wall surface 9a, 9a ': First wall surface 9b, 9b': Second wall surface 10: Screw hole 10a: Screw hole axis 11: Screw member 12: Recessed portion α: Angle formed by the axis of the screw hole and the rotation axis β ₁ : inclination angle of the second wall surface with respect to the rotation axis β ₂ : inclination angle of the second side surface with respect to the rotation axis

Claims (5)

A substantially plate-shaped throw-away tip having two cutting edges at the tip, two main side surfaces following the cutting edge, and two chip discharge grooves adjacent to the cutting edge, and a rotation shaft common to the throw-away tip In a throw-away drill, which is detachably mounted in a tip recess provided in a holder having, and is sandwiched and fixed between two inner wall surfaces facing each other by forming the tip recess of the holder,
The holder includes a first wall surface formed in a direction facing each other, and a second wall surface formed by an uneven surface extending in the distal direction following the first wall surface, and one inner wall surface A screw hole penetrating from the first wall surface formed to the outer peripheral surface of the holder,
The throw-away tip includes a first side surface that fits with the first wall surface of the holder and a second side surface that fits with the second wall surface of the holder. , A recess is formed on one of the first side surfaces,
Inserting the throw-away tip into the concave portion of the tip of the holder from the tip direction, screwing a screw member from the screw hole of the holder, and bringing the tip of the screw member into contact with the recess of the throw-away tip The throw-away tip is characterized in that the throw-away tip is pressed and fixed. 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 according to claim 1, wherein the axial direction of the screw hole is shifted to the chip discharge groove side that is close to the screw hole with respect to the rotation axis when viewed from the front end of the holder. Drill. The throw-away drill according to any one of claims 1 to 3, wherein the second wall surface and the second side surface are inclined toward the rotating shaft side toward the tip end side of the holder. 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.

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