JP2005161462A - Throw-away drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the economic effect and working stability of a throw-away drill constituted by detachably installing throw-away tips on a front face of a body part. <P>SOLUTION: The two throw-away tips 3 are butted against and detachably installed on the front face 2d of the body part 2. A back face 3c of the mutually butting throw-away tips 3 and the front face 2d of the body part 2, are composed of projecting-recessed surfaces composed of multidirectional V grooves 5 and 6. The projecting-recessed surfaces are mutually fitted, and the throw-away tips 3 are firmly fixed to the body part 2 by operating fastening force by a fastening screw 4 on its fitting part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a throw-away drill for metal working that has improved economic effects and machining stability.

  Among known throw-away cutting tools, for example, there are those shown in Patent Documents 1 to 3 below.

  In the throw-away drill of Patent Document 1, a head having two cutting blades symmetrical about the center of rotation is detachably mounted at the tip of the main body with a fastening screw. The head and the main body are fitted with each other by using radial serrations provided corresponding to the abutting surfaces, so that both can be fixed stably.

  In addition, the throw-away type drill of Patent Document 2 is configured so that a substantially triangular plate-shaped throw-away tip is oriented in the direction of rotation of the drill with the triangular face as a rake face and one side face as a flank face of the drill tip. It is attached to the main unit.

Further, Patent Document 3 discloses a drill including a cutting head, a holding portion, cooperating surfaces (mutual butting surfaces) provided on these, and a screw that forcibly brings the surfaces together. ing. The drill of this Patent Document 3 is provided with at least two grooves substantially orthogonal to one of the cooperating surfaces described above, and is provided with grooves that draw a lattice pattern across the other surface. The surfaces that cooperate using each other are fitted to each other, and the cutting head and the holding portion can be connected at four positions that are relatively rotated in the circumferential direction.
Republished patent WO02 / 005990 Japanese Patent No. 3166601 Special table 2001-506190 gazette

  Since the drill of patent document 1 forms two cutting edges in one head, when the diameter increases, the volume of the head increases, and the amount of material used increases and the head becomes expensive.

  Further, in the machining by the drill, the cutting speed becomes 0 at the rotation center portion, and the machining form crushes the work material rather than cutting, but the drill of Patent Document 1 also has a blade at the rotation center portion. Therefore, cutting resistance increases.

  The drill of Patent Document 3 has the same problem as the drill of Patent Document 1.

  Further, in the drill of Patent Document 2, since the throw-away tip is pushed to the outer peripheral side by the cutting resistance when the cutting edge bites into the work material and there is no mechanism for reliably receiving the force, the tip is easy to move. There is a high possibility that the cutting edge will be damaged due to.

  An object of the present invention is to eliminate these problems.

  In order to solve the above-described problems, in the present invention, two throw-away tips are attached to the front end of the main body so as to be detachable, and each throw-away tip constitutes a rotationally symmetrical cutting edge. In the drill, the mutual abutment surfaces of the throw-away tip and the main body portion are constituted by convex and concave surfaces formed of multi-directional V-grooves, the concave and convex surfaces are fitted to each other, and a tightening force by a fastening screw acts on the fitting portion. The throw-away tip and the main body are fixed to each other.

  In this drill, the abutting surfaces of the throw-away tip and the main body part form a multi-directional V-groove having a plurality of V-grooves in each direction, and each groove group partially intersects. It is more preferable that it is constituted by a convex / concave surface formed by combining the two.

Also, the one where the abutment surface of the throw-away tip and the main body part are provided substantially parallel to the flank surface of the drill tip,
What is provided with a gap of 0.2 mm to 1.0 mm located at the center of rotation of the drill between the rotationally symmetrical cutting edges constituted by two throwaway tips,
A positive rake angle of 5 ° to 40 ° is given to the entire cutting edge,
A chip breaker provided on the rake face along the cutting edge is also preferable.

  In the drill of the present invention, the head portion is composed of two throwaway tips, so that the throwaway tip can be reduced in size as compared with the one in which a cutting edge having a rotational center symmetrical shape is formed on a single head, It becomes possible to provide a throw-away tip that is a consumable item at a low cost.

  Further, the two throw-away tips may be the same and are arranged at rotationally symmetric positions, so that the cutting becomes a balance cut, and deep hole processing and high-precision hole processing are possible.

  Furthermore, since the throw-away tip is attached to the tip of the main body, there is no portion that interferes with the groove processing tool or the mold, and the V groove on the abutting surface can be easily processed.

  In the case where the uneven surface provided on the mutual butting surfaces is constituted by V grooves in two or more directions, the movement of the throw-away tip in the groove longitudinal direction is prevented in cooperation with the V groove group. In addition, since a plurality of V-grooves in each direction exist and form a group, the cooperation force is further increased, and the throwaway tip is stably fixed.

  In addition, when the abutment surface of the main body and the tip is provided almost parallel to the flank at the tip of the drill, the throw-away tip has a plate shape, which improves the workability of the tip. Volume is reduced and the effect of reducing raw material costs is maximized.

  Further, in the case where a gap is provided between the rotationally symmetrical cutting blades constituted by the two throwaway tips, the cutting resistance at the rotation center portion is reduced, and the cutting of the blade at the center portion hardly occurs. If this gap between the cutting edges is 0.2 mm or less, the effect is small, and if this gap is 1.0 mm or more, an uncut portion is generated at the center, which may have an adverse effect.

  In addition, those having a positive rake angle of 5 ° to 40 ° over the entire cutting edge have a high cutting resistance reduction effect. A thinning portion of a normal drill has a rake angle of 0 ° in consideration of re-grinding, has a poor sharpness, and has a high cutting resistance. On the other hand, since the drill of this invention divides the throw-away tip into two pieces, it is possible to easily give a positive rake angle to the cutting edge of the thinning portion, and it is easy to reduce the cutting resistance.

  When the chip breaker is provided on the rake face along the cutting edge, it is possible to effectively divide the chips that are difficult to break, and the troubles such as clogging of the chips and entanglement of the chips with the work material are reduced.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a first embodiment. This throw-away drill 1 includes a main body 2, two throw-away tips 3 attached to the tip of the main body 2 (end surface on the drill front side), and each throw-away tip 3 individually attached to the main body 2. It is comprised with the fastening screw 4 to fix.

  The main body 2 has two twisted grooves 2a and a shank 2b. In addition, an oil hole 2c that branches in two directions from the middle of the longitudinal direction and exits to the outer periphery of the tip is provided at the axial center. A front surface (end surface at the front end) 2d of the main body 2 is formed as a surface perpendicular to the axis, and a plurality of V grooves 5 whose depth gradually decreases toward the center of the drill are shown in FIG. Are provided in a radial arrangement.

  As shown in FIG. 3, the throw-away tip 3 constituting the head portion of the drill has a cutting edge 3a and a flank 3b at the tip of the drill. A V-groove 6 corresponding to the V-groove 5 on the main body portion side is provided on the back surface (abutting surface with the main body portion) 3c of the throw-away tip 3.

  The throwaway tip 3 is attached to the tip of the main body 2 by fitting the protrusions formed between the V grooves 5 into the V grooves 6 and the protrusions generated between the V grooves 6 into the V grooves 5, respectively. The main body 2 is fixed with the fastening screws 4.

  When the two throwaway tips 3 are mounted on the tip of the main body 2, the cutting edge 3 a is generated at a rotationally symmetrical position to form a two-blade drill. Between each cutting edge 3a of this drill, the clearance gap g of the magnitude | size of 0.2 mm-1.0 m which reduces the cutting resistance of a rotation center part is provided.

  In the throw-away drill 1 of the first embodiment, since the head portion is constituted by two independent throw-away tips, the throw-away tip can be reduced in size and cost.

  Further, there is no portion that interferes with the groove processing tool or the mold on the mutual abutting surfaces of the main body 2 and the chip 3, and the V grooves 5 and 6 on the abutting surfaces can be easily machined.

  Further, since the gap g is provided between the two cutting edges 3a and 3a, the cutting resistance at the rotation center is small, and the cutting edge at the rotation center is not easily damaged.

  FIG. 4 shows a second embodiment having a more preferable structure. In the throw-away drill 1 shown in FIG. 4, the front surface 2d of the main body 2 and the back surface 3c of the throw-away tip 3 are formed substantially parallel to the flank 3b at the tip of the drill.

  Further, the front surface 2d of the main body 2 is provided with a V-groove group in a different direction, that is, a V-groove group 5A in the A direction and a V-groove group 5B in the B direction shown in FIG. . Each V-groove group 5A, 5B is composed of a V-groove having a constant depth, and a grid pattern unevenness 7 occurs at the intersection of these V-groove groups.

  Also on the rear surface 3c of the throw-away tip 3, a V-groove group 6A in the A direction and a V-groove group 6B in the B direction corresponding to the V-groove group on the main body side are provided so as to partially intersect (FIG. 6). (See (c)). Reference numeral 8 denotes a grid pattern irregularity generated at the intersection of the V-groove group 6A in the A direction and the V-groove group 6B in the B direction.

  In the throw-away drill 1 of FIG. 4, when the throw-away tip 3 is fixed to the main body 2 with the fastening screw 4, the movement of the tip 3 in the A direction is the fitting portion of the V groove groups 5B and 6B in the B direction. Also, movement in the B direction is prevented by the fitting portions of the V groove groups 5A and 6A in the A direction. Therefore, even if the number of the fastening screws 4 is one, the throw-away tip 3 is stably fixed, and the cutting edge is not lost due to the movement of the tip.

  In addition, since the front surface 2d and the back surface 3c that face each other are formed substantially parallel to the flank surface 3b, the throw-away tip 3 has a plate shape, the volume of the tip is reduced, and the raw material cost is reduced.

  Further, as shown in FIG. 6D, since the positive rake angle θ of 5 ° to 40 ° is given to the entire area of the cutting edge 3a, the sharpness is good, and the effect of reducing the cutting resistance can be obtained. .

  The other configurations and the effects thereof are the same as those in the first embodiment, and thus the description thereof is omitted.

  In both the first embodiment and the second embodiment, as shown in FIG. 7, a chip breaker 9 can be provided on the rake face along the cutting edge 3a. Cutting troubles caused by chips that are long and extended are also prevented.

(A) Side view showing an embodiment of the drill of the present invention, (b) Enlarged side view of the main part of the drill same as above, (c) Similarly enlarged front view Front view of the main body of the drill of FIG. (A) Front view of the throw-away tip employed in the drill of FIG. 1, (b) Right side view of the tip, (c) Top view of the tip, (d) Rear view of the tip. (A) Side view showing another embodiment of the drill of the present invention, (b) Enlarged side view of the main part of the above drill, (c) Similarly enlarged front view, (d) X direction of FIG. 4 (c) Side view Front view of the main body of the drill of FIG. (A) Front view of the throw-away tip employed in the drill of FIG. 4, (b) Right side view of the tip, (c) Rear view of the tip, (d) Cross-sectional view of the tip of the tip. (A) The front view which shows the other form of a throw away tip, (b) The figure which looked at the rake face of the throw away tip of FIG. 7 (a) from the side

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Throw away type drill 2 Main-body part 2a Twist groove | channel 2b Shank 2c Oil hole 2d Front surface 3 Throw away tip 3a Cutting edge 3b Relief surface 3c Rear surface 4 Fastening screw 5, 6 V groove group 5A, 6A A direction V groove group 5B, 6B V-groove groups 7 and 8 in the B direction Unevenness with grid pattern 9 Chip breaker g Gap between cutting edges

Claims (6)

  In the throw-away type drill in which two throw-away tips are attached to the tip of the main body so as to be detachable, and each throw-away tip forms a rotationally symmetric cutting edge, the mutual butting surfaces of the throw-away tip and the main body Is composed of uneven surfaces composed of multi-directional V-grooves, the uneven surfaces are fitted to each other, and a tightening force by a fastening screw acts on the fitting portion to fix the throw-away tip and the main body portion to each other. Characteristic throw-away type drill.   In the throw-away type drill, in which two throw-away tips are attached to the tip of the main body so as to be detachable, and each throw-away tip forms a rotationally symmetric cutting edge, the mutual abutment surface of the throw-away tip and the main body However, the multi-directional V-groove is formed of a plurality of V-grooves in each direction to form a group, and is configured by a concave-convex surface formed by combining each groove group so as to partially intersect. Are fitted together, and a throw-away tip and a main body are fixed to each other by a tightening force of a fastening screw acting on the fitting portion.   The throw-away drill according to claim 1 or 2, wherein a mutual butting surface between the throw-away tip and the main body portion is provided substantially in parallel with a clearance surface at the tip of the drill.   The clearance gap between 0.2 mm-1.0 mm is provided in the rotation center of a drill between the cutting blades of the rotationally symmetrical shape comprised by two throwaway tips, The 1 thru | or characterized by the above-mentioned. The throw-away drill according to any one of 3 above.   The throwaway drill according to any one of claims 1 to 4, wherein a positive rake angle of 5 ° to 40 ° is given to the entire area of the cutting edge.   The throwaway drill according to any one of claims 1 to 5, wherein a chip breaker is provided on a rake face along the cutting edge.

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