JP6342662B2 - Drill and method of manufacturing cut product using the same - Google Patents

Description

  The present invention relates to a drill used for cutting and a method for manufacturing a cut product.

  Conventionally, the drill of patent document 1 is known as a drill used for cutting of work materials, such as a metal member. The drill described in Patent Literature 1 includes a cutting edge and a thinning cutting edge portion formed at the tip of the drill body, and a helical chip discharge groove extending from the tip side toward the rear end side on the outer periphery of the drill body. ing. In the drill described in Patent Document 1, the area of the inner wall surface facing the rear side in the rotation direction in the chip discharge groove is increased. As a result, it is possible to divide the chips generated by the thinning cutting edge portion and the chips generated by the cutting edge, and the chips generated by the cutting edge are stably curled.

JP 2005-169528 A

  In recent years, it has been required to increase the thickness of the drill core in order to increase the strength of the drill. In particular, in a drill having a configuration in which the tip portion of the drill body can be exchanged, it is required to increase the core thickness of the drill in order to connect the tip portion and the body portion. However, when the core thickness of the drill is increased in this way, the length of the thinning cutting edge portion constituted by the thinning blade and the chisel edge becomes very long. Becomes larger. Specifically, since the pitch of the chip curl increases as the thinning cutting edge becomes longer, the discharge direction is difficult to control. As a result, the problem that clogging of chips occurs or the extended chips get entangled with the holder arises.

  This invention is made | formed in view of said subject, and it aims at providing the drill which can discharge | emit chips stably even if the core thickness of a drill becomes large.

A drill according to an aspect of the present invention is a rod-shaped drill body that is rotated around a rotation axis, a pair of main cutting blades that are positioned at a distal end portion of the drill body, and the distal end portion, In a side view from a direction perpendicular to the rotation axis, the pair of linear thinning blades extending from the pair of main cutting blades toward the rotation axis, respectively, and the tip portion are positioned along the rotation axis. A chisel edge that intersects with the rotation axis and connects the pair of thinning blades, and extends from the pair of thinning blades toward the rear end side of the drill body, and extends from the inner peripheral side to the outer periphery. wherein a planar first cutting face inclined so as to be located behind the rotational direction of the rotary shaft, respectively from the pair of main cutting edge toward the rear end side of the drill body extending toward the side The a pair second rake surface inclined so as to be located behind the rotational direction with respect to the first rake face, the rear end of the drill body from the portion adjacent to the pair of thinning edge in the chisel edge And a third rake face extending toward the outer periphery of the drill body, and a spiral extending around the rotation axis from the second rake face toward the rear end of the drill body. And a pair of chip discharge grooves. And the ridgeline of the said 1st rake face and the said 2nd rake face inclines so that it may go to an outer peripheral side from an inner peripheral side as it goes to the rear end side from the front end side of the said drill main body. The first rake face, the second rake face, and the third rake face are inclined so as to be positioned rearward in the rotational direction from the front end side to the rear end side of the drill body. An inclination angle of the second rake face with respect to the rotation axis and an inclination angle of the third rake face with respect to the rotation axis are larger than an inclination angle of the first rake face with respect to the rotation axis.

  Chips generated at the chisel edge and chips generated at the pair of main cutting edges have different shapes, so chips generated at the pair of thinning blades located between these chips are generated at the chisel edge. A pulling force is applied to the chips produced by the pair of main cutting edges. However, since the first rake face has a flat surface shape, the possibility of cracks occurring in the chips generated by the pair of thinning blades is reduced.

  And in the drill of the said aspect, the 1st rake face which continues a pair of thinning blade inclines toward the back of a rotation direction as it goes to an outer peripheral side from an inner peripheral side. In this way, chips generated by the chisel edge and the pair of thinning blades easily flow to the chip discharge groove located on the rear end side of the second rake face.

  At this time, the ridgeline between the first rake face and the second rake face is inclined so as to go from the inner peripheral side to the outer peripheral side as it goes from the front end side to the rear end side of the drill body. Therefore, the chips generated by the chisel edge and the pair of thinning blades and proceeding from the inner peripheral side toward the outer peripheral side from the front end side to the rear end side of the drill body are located on the rear end side of the second rake face. It can be stably guided to the chip discharge groove. From the above, it is possible to discharge chips stably even when the core thickness of the drill is increased.

It is a perspective view which shows the drill of one Embodiment of this invention. It is the perspective view which expanded the front-end | tip part in the drill shown in FIG. It is a front view from the front-end | tip direction in the drill shown in FIG. It is the conceptual diagram which simplified the structure of the drill shown in FIG. It is a side view from the A1 direction in the drill shown in FIG. It is the side view to which area | region A3 in the drill shown in FIG. 5 was expanded. It is a side view from the A2 direction in the drill shown in FIG. It is sectional drawing of D1-D1 cross section in the drill shown in FIG. It is sectional drawing of D2-D2 cross section in the drill shown in FIG. It is sectional drawing of D3-D3 cross section in the drill shown in FIG. It is a perspective view which shows 1 process of the manufacturing method of the cut workpiece of one Embodiment of this invention. It is a perspective view which shows 1 process of the manufacturing method of the cut workpiece of one Embodiment of this invention. It is a perspective view which shows 1 process of the manufacturing method of the cut workpiece of one Embodiment of this invention.

  Hereinafter, the drill 1 of one Embodiment of this invention is demonstrated in detail using drawing. However, in the drawings referred to below, for convenience of explanation, among the constituent members of the embodiment, only the main members necessary for explaining the present invention are shown in a simplified manner. Accordingly, the drill of the present invention may include any component not shown in the drawings to which the present specification refers. Moreover, the dimension of the member in each figure does not represent the dimension of an actual structural member, the dimension ratio of each member, etc. faithfully.

<Drill>
As shown in FIGS. 1 to 10, the drill 1 of the present embodiment includes a drill body 3 (hereinafter also simply referred to as a body 3), a pair of main cutting edges 5, a pair of thinning edges 7, a chisel edge 9, A first rake face 11, a second rake face 13, and a chip discharge groove 15 (hereinafter also simply referred to as a discharge groove 15) are provided.

  The main body 3 has a rotation axis (rotation center axis) X, and has a rod-like configuration extending along the rotation axis X. The main body 3 rotates around the rotation axis X in the direction of the arrow Y1 around the rotation axis X during cutting. The main body 3 in the present embodiment includes a gripping part 17 called a shank that is gripped by a rotating spindle or the like of a machine tool (not shown), and a cutting part 19 called a body that is located on the tip side of the gripping part 17. It is equipped with. The gripping part 17 is a part designed according to the shape of a spindle or the like in the machine tool. The cutting part 19 is a part which contacts a work material, and is a part having a main role in the cutting work of the work material.

  Further, in the cutting portion 19 in the present embodiment, the tip side portion including the pair of main cutting edges 5, the pair of thinning edges 7, the chisel edge 9, the first rake face 11 and the second rake face 13 is the rear end side. It becomes the structure which can be attached or detached with respect to these parts. Of course, there is no problem even if the cutting part 19 has a configuration composed of one member instead of the above configuration.

  The cutting part 19 in the present embodiment has a shape obtained by removing a portion corresponding to the discharge groove 15 from a cylinder extending along the rotation axis X. A portion of the outer periphery of the cutting portion 19 excluding the discharge groove 15, that is, a portion located between the pair of discharge grooves 15 is a land surface 21. In the present embodiment, the land surface 21 has a margin 21a adjacent to the discharge groove 15 at the rear in the rotation direction of the rotation axis X, and a second number adjacent to the margin 21a at the rear in the rotation direction of the rotation axis X. And a surface 21b.

  In a cross section including the rotation axis X and perpendicular to the rotation axis X, the margin 21a has an arc shape located on the same circle. The diameter of this same circle corresponds to the outer diameter of the cutting part 19. The second surface 21b is a surface provided with a gap in order to avoid friction between the outer periphery of the drill 1 and the work surface during the cutting process. For this reason, the distance from the rotation axis X of the second picking surface 21b is shorter than the margin 21a.

  In the drill 1 of the present embodiment, for example, the outer diameter of the cutting portion 19 is set to 6.0 mm to 42.5 mm. Moreover, the drill 1 of this embodiment sets L = 3D-12D, for example, when the length of an axis (length of the cutting part 19) is set to L and the diameter (outer diameter of the cutting part 19) is set to D. Is done.

  The material of the main body 3 is a cemented carbide containing WC (tungsten carbide) and Co (cobalt) as a binder, and an additive such as TiC (titanium carbide) or TaC (tantalum carbide). And alloys such as stainless steel and titanium.

  The drill 1 includes a cutting edge for cutting a work material at the tip of the main body 3. In this embodiment, as shown in FIGS. 2 and 3, a pair of main cutting edges 5 and a pair of cutting edges are used. A thinning blade 7 and a chisel edge 9 are provided. The pair of main cutting blades 5, the pair of thinning blades 7 and the chisel edge 9 are formed at the distal end portion of the main body 3, that is, the distal end portion of the cutting portion 19. The pair of main cutting blades 5 are located on the outer peripheral side of the pair of thinning blades 7 and the chisel edge 9, and are located on the outermost peripheral side of the cutting blade. The chisel edge 9 is located on the innermost peripheral side of the cutting edge. The pair of thinning blades 7 are located between the pair of main cutting blades 5 and the chisel edge 9.

As shown in FIGS. 3 and 4, the pair of main cutting edges 5 are located apart from each other with the pair of thinning edges 7 and the chisel edge 9 interposed therebetween. The pair of main cutting edges 5 are 180 ° rotationally symmetric about the rotation axis X of the main body 3 when viewed from the front end (front view). Since the pair of main cutting edges 5 are rotationally symmetric as described above, it is possible to suppress blurring that occurs between the pair of main cutting edges 5 when the pair of main cutting edges 5 bite against the work material. Therefore, stable drilling can be performed.

  As shown in FIGS. 3 and 4, the pair of main cutting edges 5 in the present embodiment are configured such that at least a part thereof has a concave curve shape when viewed from the front end. Accordingly, the chips generated by the pair of main cutting edges 5 can be easily curled, so that the chips can be easily discharged by the pair of discharge grooves 15. Further, in order to improve the machinability, the pair of main cutting edges 5 are provided so that the rotation trajectory of the pair of main cutting edges 5 is inclined with respect to the rotation axis X when cut along a virtual plane including the rotation axis X. ing. The inclination angle of the rotation trajectory of the pair of main cutting edges 5 with respect to the rotation axis X is set to about 50 to 85 °.

  Each of the pair of thinning blades 7 has a linear shape, and extends from the pair of main cutting edges 5 toward the rotation axis X in a side view from the direction orthogonal to the rotation axis X, as shown in FIG. Yes. When a pair of virtual straight lines are stretched along the pair of thinning blades 7 in a side view, the angle at which these virtual straight lines intersect is set to about 130 to 170 °, for example.

  The chisel edge 9 protrudes to the most distal end side of the drill 1. At this time, the chisel edge 9 has a configuration in which a portion intersecting with the rotation axis X protrudes to the most distal direction side and is inclined so as to move toward the rear end side of the main body 3 as it is away from the rotation axis X.

  The chisel edge 9 intersects the rotation axis X and is connected to the pair of thinning blades 7 in a front end view from the direction along the rotation axis X. When the chisel edge 9 and the main cutting edge 5 are directly connected, since the angle at which the chisel edge 9 and the main cutting edge 5 intersect is large, a large load is applied between the chisel edge 9 and the main cutting edge 5. It becomes easy. However, in the drill 1 of this embodiment, the thinning blade 7 is provided between the chisel edge 9 and the main cutting edge 5. Therefore, the possibility that such a large load is applied to a specific region of the cutting blade can be reduced.

  The pair of thinning blades 7 are 180 ° rotationally symmetric about the rotation axis X of the main body 3 when viewed from the front end. Further, the pair of thinning blades 7 are inclined with respect to the chisel edge 9 when viewed from the tip. Therefore, the part comprised by a pair of thinning blade 7 and chisel edge 9 in a cutting blade is comprised so that S character may be drawn, when it sees at the front-end | tip.

  In regions along the pair of main cutting blades 5, the pair of thinning blades 7 and the chisel edge 9, rake surfaces are provided. As a rake face along the pair of thinning blades 7, a first rake face 11 extending from the pair of thinning blades 7 toward the rear end side of the drill body 3 is provided. The first rake face 11 has a flat surface shape and is inclined toward the rear in the rotational direction as it goes from the inner peripheral side to the outer peripheral side. At this time, although not particularly illustrated, in the cross section orthogonal to the rotation axis X, an angle at which the straight line extending from the rotation axis X toward the center of the first rake face 11 intersects the first rake face 11 is 20. It is set to about ~ 40 °.

  As the rake face along the pair of main cutting edges 5, a second rake face 13 extending from the pair of main cutting edges 5 toward the rear end side of the drill body 3 is provided. The second rake face 13 is inclined with respect to the first rake face 11 toward the rear in the rotational direction. At this time, in the cross section orthogonal to the rotation axis X, the angle at which the first rake face 11 intersects with the tangent line in contact with the inner peripheral end of the second rake face 13 is set to about 150 to 170 °. .

A pair of discharge grooves 15 are provided on the outer periphery of the cutting part 19 in the main body 3. The pair of discharge grooves 15 are respectively connected to the second rake face 13 at the tip side, and spirally around the rotation axis X from the second rake face 13 toward the rear end of the main body 3. It extends to. At this time, in order to stably hold the main body 3 with a machine tool, the pair of discharge grooves 15 are formed only in the cutting portion 19 and are not formed in the holding portion 17.

  The pair of discharge grooves 15 is mainly intended to discharge chips generated by the pair of main cutting blades 5, the pair of thinning blades 7 and the chisel edge 9. At the time of cutting, the chips formed on one of the pair of main cutting edges 5 are the discharge grooves connected to the main cutting edges 5 through the second rake face 13 between the pair of discharge grooves 15. 15 is discharged to the rear end side of the main body 3.

  Further, the chips formed on the other side of the pair of main cutting edges 5 are the discharge grooves connected to the other main cutting edge 5 of the pair of discharge grooves 15 with the second rake face 13 therebetween. 15 is discharged to the rear end side of the main body 3. One of the pair of discharge grooves 15 in the present embodiment rotates the other of the pair of discharge grooves 15 by 180 ° around the rotation axis X in order to flow the chips generated by each of the pair of main cutting edges 5 satisfactorily. Are formed so as to overlap each other.

  The depth of each of the pair of discharge grooves 15 can be set to about 10 to 40% with respect to the outer diameter of the cutting portion 19. Here, the depth of the discharge groove 15 means a value obtained by subtracting the distance between the bottom of the discharge groove 15 and the rotation axis X from the radius of the main body 3 in a cross section orthogonal to the rotation axis X. Therefore, the diameter of the core thickness indicated by the diameter of the inscribed circle in the cross section orthogonal to the rotation axis X in the main body 3 is set to about 20 to 80% with respect to the outer diameter of the cutting portion 19. Specifically, for example, when the outer diameter D of the cutting part 19 is 20 mm, the depth of the discharge groove 15 can be set to about 2 to 8 mm.

  The twist angle of the discharge groove 15 extending in a spiral shape is set to about 3 to 45 °, for example. The twist angle may be constant from the front end to the rear end of the discharge groove 15, but is not particularly limited to such a configuration. That is, the above-described twist angle may change midway from the front end to the rear end of the discharge groove 15. The discharge groove 15 in the drill 1 of the present embodiment has a configuration in which the twist angle is relatively smaller in the central portion sandwiched between these portions than the front end portion and the rear end portion of the discharge groove 15.

  The torsion angle in the present embodiment is an angle formed by a leading edge that is an intersection line formed by the discharge groove 15 and the margin 21a and a virtual straight line that passes through one point on the leading edge and is parallel to the rotation axis X. I mean.

  In the drill 1 of this embodiment, it has the 1st rake face 11 and the 2nd rake face 13 as a rake face, and the 2nd rake face 13 is a rotation direction with respect to the 1st rake face 11. Inclined towards the back of the. At this time, the ridge line between the first rake face 11 and the second rake face 13 is inclined so as to go from the inner peripheral side to the outer peripheral side as it goes from the front end side to the rear end side of the main body 3.

  Since the chips generated by the chisel edge 9 and the chips generated by the pair of main cutting edges 5 have different shapes, the chips generated by the pair of thinning blades 7 positioned between these chips include a chisel edge. The pulling force is applied to the chips generated in 9 and the chips generated in the pair of main cutting edges 5. However, since the 1st rake face 11 is a flat surface shape, possibility that a crack will arise in the chip generated with a pair of thinning blades 7 is reduced.

And in the drill 1 of the said aspect, the 1st rake face 11 continuing to a pair of thinning blade 7 inclines toward the back of a rotation direction as it goes to an outer peripheral side from an inner peripheral side. In this way, the chips generated by the chisel edge 9 and the pair of thinning blades 7 easily flow to the chip discharge groove 15 located on the rear end side of the second rake face 13.

  At this time, the ridge line between the first rake face 11 and the second rake face 13 is inclined so as to go from the inner peripheral side to the outer peripheral side as it goes from the front end side to the rear end side of the drill body 3. Therefore, the chip generated by the chisel edge 9 and the pair of thinning blades 7 and progressing from the inner peripheral side toward the outer peripheral side as it goes from the front end side to the rear end side of the drill body 3 is transferred to the rear end of the second rake face 13. It can be stably guided to the chip discharge groove 15 located on the side. From the above, even if the core thickness of the drill 1 is increased, the chips can be discharged stably.

  Further, in the drill 1 of the present embodiment, the width of the first rake face 11 in the direction orthogonal to the rotation axis X decreases from the front end side to the rear end side of the main body 3. When the 1st rake face 11 is such a structure, it can prevent that the flow of chips changes rapidly in the vicinity of the rear end of the 1st rake face 11. Therefore, the chips generated by the chisel edge 9 and the pair of thinning blades 7 are suppressed from flowing into the discharge groove 15 rapidly, and gradually flow easily. Thereby, the possibility that chips are clogged in the vicinity of the rear end of the first rake face 11 can be reduced.

  In the drill 1 of the present embodiment, the first rake face 11 and the second rake face 13 are inclined toward the rear in the rotation direction from the front end side to the rear end side of the main body 3. At this time, the inclination angle θ1 of the first rake face with respect to the rotation axis X may be larger than the inclination angle θ2 of the second rake face 13 with respect to the rotation axis X. However, as shown in FIGS. It is preferable that the inclination angle θ1 of the surface with respect to the rotation axis X is smaller than the inclination angle θ2 of the second rake surface 13 with respect to the rotation axis X.

  In such a case, the rake angle of the second rake face 13 connected to the main cutting edge 5 has a portion larger than the rake angle of the first rake face 11 connected to the pair of thinning blades 7. become. Therefore, chips flowing on the first rake face can easily flow into the second rake face 13. Moreover, since the space where the chip flows on the second rake face 13 can be secured widely, the chip can be favorably flowed to the discharge groove 15.

  In the drill 1 of the present embodiment, as shown in FIG. 8, the inclination angle θ3 of the rake face with respect to the rotation axis X in the portion adjacent to the pair of thinning blades 7 in the chisel edge 9 is also the first rake face 11. It is configured to be larger than the inclination angle θ1 with respect to the rotation axis X.

<Manufacturing method of cut product>
Next, the manufacturing method of the cut workpiece which concerns on embodiment of this invention is demonstrated in detail, giving the case where the drill 1 of above-mentioned embodiment is used as an example. Hereinafter, a description will be given with reference to FIGS.

  The manufacturing method of the cut workpiece according to the present embodiment includes the following steps (1) to (4).

  (1) The process of arrange | positioning the drill 1 upwards with respect to the prepared workpiece 101 (refer FIG. 11).

  (2) A step of rotating the drill 1 about the rotation axis X in the direction of the arrow Y1 to bring the drill 1 closer to the work material 101 in the Y2 direction (see FIGS. 11 and 12).

This step can be performed, for example, by fixing the work material 101 on a table of a machine tool to which the drill 1 is attached and bringing the drill 1 closer in a rotated state. In this step, the work material 101 and the drill 1 may be relatively close to each other, and the work material 101 may be close to the drill 1.

  (3) By bringing the drill 1 closer to the work material 101, the pair of main cutting blades, the pair of thinning blades, and the chisel edge of the rotating drill 11 are brought into contact with desired positions on the surface of the work material 101. Then, a step of forming a processing hole 103 (through hole) in the work material 101 (see FIG. 12).

  In this step, from the viewpoint of obtaining a good finished surface, it is preferable to set a part of the cutting end 19 of the drill 1 so as not to penetrate the work material 101 on the rear end side. That is, by making this part of the area function as an area for chip discharge, it is possible to achieve excellent chip discharge through the area.

  (4) A step of separating the drill 1 from the work material 101 in the Y3 direction (see FIG. 13).

  Also in this step, similarly to the above-described step (2), the work material 101 and the drill 1 may be relatively separated from each other. For example, the work material 101 may be separated from the drill 1.

  By going through the steps as described above, a cut workpiece having the processed hole 103 can be obtained.

  In addition, when performing the cutting of the workpiece 101 as described above a plurality of times, for example, when forming a plurality of processed holes 103 for one workpiece 101, the drill 1 is rotated. What is necessary is just to repeat the process which makes a pair of main cutting blade, a pair of thinning blade, and a chisel edge of the drill 1 contact the different location of the workpiece 101, hold | maintaining a state.

  As mentioned above, although one embodiment was illustrated about the drill which concerns on this invention, it cannot be overemphasized that the drill of this invention is not limited to these, and can be made into arbitrary things, without deviating from the summary of this invention. .

1 ... Drill 3 ... Drill body (main body)
5 ... main cutting edge 7 ... thinning blade 9 ... chisel edge 11 ... first rake face 13 ... second rake face 15 ... chip discharge groove (discharge groove)
17 ... gripping part 19 ... cutting part 21 ... land surface 21a ... margin 21b ... second picking surface 101 ... work material 103 ... machining hole

Claims (4)

A rod-shaped drill body that rotates about a rotation axis;
A pair of main cutting blades located at the tip of the drill body;
A pair of linear thinning blades that are located at the tip portion and extend from the pair of main cutting edges toward the rotation axis in a side view from a direction orthogonal to the rotation axis,
A chisel edge that is located at the distal end and intersects the rotational axis and connects the pair of thinning blades in a distal end view from a direction along the rotational axis;
A flat first rake face that extends from the pair of thinning blades toward the rear end side of the drill body, and inclines so as to be positioned rearward in the rotational direction of the rotary shaft from the inner peripheral side to the outer peripheral side. When,
Said extending respectively from a pair of main cutting edge toward the rear end side of the drill body, the pair of second rake surface inclined so as to be located behind the rotational direction with respect to the first rake face,
A third rake face extending from a portion of the chisel edge adjacent to the pair of thinning blades toward the rear end of the drill body;
A pair of chip discharge grooves provided on the outer periphery of the drill body and extending spirally around the rotation axis from the second rake face toward the rear end of the drill body;
The ridge line between the first rake face and the second rake face is inclined so as to go from the inner peripheral side to the outer peripheral side as it goes from the front end side to the rear end side of the drill body ,
The first rake face, the second rake face, and the third rake face are each inclined so as to be positioned rearward in the rotational direction from the front end side to the rear end side of the drill body. ,
The tilt angle of the second rake face with respect to the rotation axis and the tilt angle of the third rake face with respect to the rotation axis are greater than the inclination angle of the first rake face with respect to the rotation axis. .   2. The drill according to claim 1, wherein a width of the first rake face in a direction orthogonal to the rotation axis decreases from a front end side to a rear end side of the drill body.   3. The drill according to claim 1, wherein a length of the chisel edge is longer than a length of the pair of thinning blades in a front end view from a direction along the rotation axis. A step of rotating the drill according to any one of claims 1 to 3 around the rotation axis, and the pair of main cutting blades, the pair of thinning blades, and the chisel edge of the rotating drill. A step of contacting the cutting material;
And a step of separating the drill from the work material.

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