JP5918166B2 - Cutting insert and drill head - Google Patents

Description

  The present invention relates to a cutting insert capable of improving hole machining accuracy and a drill head using the cutting insert.

  Conventionally, as a drill head using a cutting insert as a blade body, for example, the one described in Patent Document 1 is known. This drill head has a substantially cylindrical head main body that forms a chip discharge path with a hollow interior opened to the rear end side by a cutting head portion on the front side and a screw shank portion provided with an external thread on the outer periphery on the rear side. A large and small fan-shaped chip discharge port communicating with the chip discharge path is opened at the front end face of the cutting head portion. The cutting inserts are secured to the three cutting blade mounting seats recessed along the edge walls in the substantially common radial direction of both the chip discharge ports, respectively, and the outer peripheral surface of the cutting head portion. The substantially paddle-shaped guide pads are fixed to the groove-shaped pad mounting recesses along the head axis direction, which are recessed at the two locations, via mounting screws, respectively.

JP 2008-254089 A

  However, since the cutting insert used in the drill head has a parallelogram shape as a whole, a portion other than the cutting edge of the cutting insert is formed on the inner wall surface of the work hole for machining the drill head. There was a problem that the hole machining accuracy was reduced due to interference.

  Therefore, in view of the above problems, an object of the present invention is to provide a cutting insert capable of improving the drilling accuracy and a drill head using the cutting insert.

  The object of the present invention is achieved by the following means. In addition, although the code | symbol in a parenthesis attaches the referential mark of embodiment mentioned later, this invention is not limited to this.

According to the cutting insert according to the invention of claim 1, the upper surface (50a), a lower surface (50b), the upper surface (50a) and a lower surface (50b) in plan view substantially and a side surface (50c) which is integrally formed It has a cutting insert body (50) made of a rectangular plate,
The upper surface (50a), the side surface (50c), and the lower surface (50b) and the side surface (50c) intersect with each other to form an upper surface side and a lower surface side intersecting portion composed of a ridge line having a substantially rectangular shape in plan view.
Among these upper and lower surface side intersections, a pair of upper and lower surfaces facing each other in parallel with the center line (OL) with the center line (OL) passing through the center point (O) of the cutting insert body (50) as the axis of symmetry. A straight cutting edge (51) is formed at the side intersection ,
Furthermore, among these upper and lower surface side crossing portions , a pair of the two orthogonally opposite to the center line (OL) with the center line (OL) passing through the center point (O) of the cutting insert body (50) as the axis of symmetry . A flank (52) inclined in an upside down shape toward the center point (O) from both end edges (51a) of the cutting edge (51) is formed at the upper and lower surface side intersections ,
Furthermore, among the upper and lower surface side intersections , stepped chip breakers on the upper surface side and the lower surface side are provided on the side surface (50c) of the upper and lower surface side intersection portion provided with the cutting edge (51) on the upper and lower surface side. (53) is formed.

On the other hand, according to the drill head according to the second aspect of the present invention, each of the plurality of positions including at least the center side, the intermediate side, and the outer peripheral side of the distal end surface (2a) of the cylindrical drill head body (2) cooperates. Then, a blade body for cutting the work material (W) is provided, and at least the center-side blade body is made of the cutting insert (center-side cutting insert 5A) according to claim 1, and the cutting insert (center-side cutting insert) When 5A) is provided on the tip surface (2a) of the drill head body (2), the drill head body (2) is provided in a direction orthogonal to the central axis (G) of the drill head body (2) in a front view.

Moreover, according to the drill head which concerns on invention of Claim 3 , in the drill head of the said Claim 2 , the said cutting insert (center side cutting insert 5A) is used as the front end surface (2a) of the said drill head main body (2). Is provided so as to tilt toward the base end side of the drill head body (2).

  Next, effects of the present invention will be described with reference numerals in the drawings. In addition, although the code | symbol in a parenthesis attaches the referential mark of embodiment mentioned later, this invention is not limited to this.

  According to the invention which concerns on Claim 1, the center point (50) of the said cutting insert main body (50) from the cutting edge (51) both-ends edge (51a) provided in at least one outer peripheral side surface of the cutting insert main body (50) which consists of polygons ( Since the flank (52) is provided on the inclined surface inclined toward (O), the flank (52) is recessed with respect to the cutting edge (51).

  Therefore, according to the present invention, the portion other than the cutting edge (51) interferes with the inner wall surface (W1) of the work material processing hole in the drill head rotation direction (see P1 shown in FIGS. 2, 3 and 5). Therefore, the hole machining accuracy can be improved.

Moreover, according to the invention which concerns on Claim 1 , the said cutting insert main body (OL) which is a left-right symmetric in planar view on the centerline (OL) which passes along the center point (O) of the cutting insert main body (50) as a symmetry axis. 50) is provided with cutting edges (51) on the upper and lower surfaces of the side surface , and from both end edges (51a) of the cutting edge (51) so as to be symmetric with respect to the center line (OL) in plan view. Since the flank (52) is provided on the inclined surface that is inclined toward the center line (OL) toward the center point (O), the blade edge is renewed by turning 180 ° and reversing the upper and lower surfaces for four times. Can be used.

On the other hand, according to the invention of claim 2, when the cutting insert (center-side cutting insert 5A) is provided on the tip surface (2a) of the drill head body (2), the center axis (G of the drill head body (2) ), The thickness of the drill head body (2) with respect to the radial direction (see T1 and T2 shown in FIG. 3) increases, so that even if it receives a large cutting reaction force (P2), it will not be damaged. Thus, the strength can be increased.

Moreover, according to the invention which concerns on Claim 3 , when providing the cutting insert (center side cutting insert 5A) in the front end surface (2a) of a drill head main body (2) as mentioned above, the said drill head main body (2) Therefore, a portion other than the cutting edge (51) can be prevented from interfering with the upper wall surface of the work material processing hole. Therefore, according to the present invention, it is possible to prevent a situation in which the hole machining accuracy is lowered, and it is possible to further improve the hole machining accuracy.

It is a perspective view showing the whole drill head concerning one embodiment of the present invention. (A) is a front view of the drill head concerning the embodiment, (b) is a top view. It is a plane enlarged view of the drill head concerning the embodiment. The cutting insert used for the drill head concerning the embodiment is shown, (a) is a top view of the cutting insert, and (b) is a front view. The drill head which concerns on other embodiment is shown, (a) is a front view of the drill head, (b) is a top view.

  Hereinafter, an embodiment of a drill head according to the present invention will be specifically described with reference to FIGS.

  As shown in FIGS. 1 and 2, the drill head 1 has a substantially cylindrical drill head main body 2 having a hollow portion opened on the base end side, and a conical distal end surface 2 a of the drill head main body 2 has As shown in FIGS. 1 and 2B, two large and small chip discharge ports 3 and 4 communicating with the hollow portion are provided. An indexable (throw away) type center side cutting insert 5 </ b> A and an outer peripheral side cutting insert 5 </ b> B are fastened by screws 6 to the opening side edge of the large chip discharge port 3 along the radial direction of the drill head. Further, an indexable (throw away) type intermediate cutting insert 5C is fastened by a screw 6 to the opening side edge of the small chip discharge port 4 along the radial direction of the drill head. As shown in FIGS. 1 and 2, guide pads 7 </ b> A and 7 </ b> B are fastened to the outer peripheral surface 2 b of the drill head main body 2 by screws (not shown) on the distal end side. A male screw 8 is engraved on the base end side of the drill head body 2.

  Here, the center-side cutting insert 5A and the intermediate-side cutting insert 5C will be specifically described with reference to FIG. 4. The center-side cutting insert 5A and the intermediate-side cutting insert 5C include an upper surface 50a, a lower surface 50b, It has a cutting insert body 50 made of a thick plate having a substantially quadrangular shape (strictly, a hexagonal shape) provided with an upper surface 50a and a side surface 50c integrally formed with the lower surface 50b. Of the intersecting portions of the upper surface 50a and the side surface 50c and the lower surface 50b and the side surface 50c, the center line OL passing through the center point O of the cutting insert body 50 shown in FIG. A straight cutting edge 51 is formed in the part. Further, the remaining intersections of the upper surface 50a and the side surface 50c and the lower surface 50b and the side surface 50c are center points from both end edges 51a of the cutting edge 51 so as to be symmetrical in plan view with the center line OL as the axis of symmetry. A flank 52 is formed on an inclined surface that is linearly inclined toward the center line OL toward O and formed in a reverse letter shape. Further, stepped chip breakers 53 are formed on the upper surface side and the lower surface side on the peripheral surface of the side surface 50c provided with the cutting edges 51 on the upper and lower surfaces. Furthermore, a screw insertion hole 54 through which the screw 6 (see FIGS. 1 and 2) penetrating in the thickness direction can be inserted from any of the upper and lower surfaces is provided at the center of the cutting insert body 50. In addition, since the outer peripheral side cutting insert 5B uses the cutting insert generally used, description is abbreviate | omitted.

  When the drill head 1 configured in this way is used for deep hole cutting, a male screw 8 engraved on the base end side of the drill head main body 2 is screwed to the distal end side of a hollow boring bar (not shown). The drill head 1 is rotated by connecting the boring bar to a drive shaft such as a spindle of a machine tool, or the work material W (see FIGS. 2 and 3) is rotated. The workpiece W is cut in cooperation with the cutting inserts 5A to 5C to form deep holes. The relative rotation direction of the drill head 1 is a counterclockwise direction indicated by an arrow P1 in FIGS. 2B and 3. During this cutting process, the coolant is pressurized through the gap between the cutting hole and the boring bar. It supplies to a cutting site | part, is made to flow in into a hollow part from the chip discharge ports 3 and 4 with the chip | tip which generate | occur | produces in a cutting site | part, and discharges outside through the inside of a hollow boring bar.

  By the way, in this cutting process, as shown in FIG. 3, it is the center side cutting insert 5A that cuts the workpiece W first among the cutting inserts 5A to 5C, and then the intermediate side cutting insert 5C. And finally, the work material W will be cut with the outer peripheral side cutting insert 5B. At this time, since the center-side cutting insert 5A and the intermediate-side cutting insert 5C receive a great cutting reaction force P2 when cutting the work material W, even if the cutting reaction force P2 is received, the center-side cutting insert It is necessary to increase the strength so that 5A and the intermediate cutting insert 5C are not lost. Therefore, the center-side cutting insert 5A and the intermediate-side cutting insert 5C are provided on the distal end surface 2a of the drill head body 2 in a direction orthogonal to the center axis G of the drill head body 2 shown in FIG. 2 and 3). This increases the thickness of the center-side cutting insert 5A and the intermediate-side cutting insert 5C in the radial direction of the drill head body 2 (see T1 and T2 shown in FIG. 3), and therefore receives a large cutting reaction force P2. Also, the strength can be increased so that the center-side cutting insert 5A and the intermediate-side cutting insert 5C are not lost.

  Furthermore, when the center-side cutting insert 5A and the intermediate-side cutting insert 5C are provided on the distal end surface 2a of the drill head body 2 as described above, the center-side cutting insert 5A that cuts the work material W first is the center cutting insert 5A. As shown in FIG. 1, the center side is arranged so that portions other than the cutting edge 51 do not interfere with the upper wall surface of the work material processing hole generated by cutting the work material W with the cutting edge 51 of the side cutting insert 5A. The upper surface 50a of the cutting insert main body 50 of the cutting insert 5A is fixed to the distal end surface 2a of the drill head main body 2 by screws 6 so that the upper surface 50a tilts toward the base end side of the drill head main body 2. If it does in this way, parts other than the cutting edge 51 of the said center side cutting insert 5A will be on the upper wall surface of the work material processing hole produced by cutting the workpiece W with the cutting edge 51 of the center side cutting insert 5A. Since interference does not occur, it is possible to prevent a situation in which the hole machining accuracy is lowered.

  On the other hand, the center-side cutting insert 5A and the intermediate-side cutting insert 5C, when the workpiece W is cut with the cutting edge 51, work material processing in the drill head rotation direction (see P1) as shown in FIG. In order to prevent the portions other than the cutting edge 51 from interfering with the inner wall surface W1 of the hole, the inclined face is formed in a straight and inclined shape from both end edges 51a of the cutting edge 51 toward the center point O. A flank 52 is formed. Therefore, according to the cutting insert (center side cutting insert 5A and intermediate side cutting insert 5C) of the present embodiment, the flank 52 has a recessed shape with respect to the cutting edge 51, and therefore the drill head rotation direction (P1) It is possible to prevent portions other than the cutting edge 51 from interfering with the inner wall surface W1 of the work material processing hole of (see). Therefore, according to the present embodiment, the hole machining accuracy can be improved.

  Further, the center-side cutting insert 5A and the intermediate-side cutting insert 5C have linear cutting edges 51 formed in portions that are symmetrical in plan view with a center line OL passing through the center point O of the cutting insert body 50 as a symmetry axis. Further, the center line OL is linearly inclined from the both end edges 51a of the cutting edge 51 toward the center point O toward the center line OL so as to be symmetric with respect to the center line OL as an axis of symmetry. Since the flank 52 is formed on the inclined surface that is formed, the blade edge can be renewed by turning the blade 180 degrees for convenient use twice.

  In addition, in this embodiment, although demonstrated using the drill head 1 which fixes the cutting insert 5A-5C directly to the front end surface 2a of the drill head main body 2 with the screw 6, it is not restricted to this, For example, FIG. As shown in the drill head 100 shown, the cutting inserts 5 </ b> A to 5 </ b> C are fixed to the cartridge 102 fixed to the tip end surface 2 a of the drill head main body 2 by screws 101 (see FIG. 5B). Is also applicable.

  Moreover, in this embodiment, although the example using the cutting insert generally used for the outer peripheral side cutting insert 5B was shown, the cutting insert generally used also for the intermediate | middle side cutting insert 5C was used. Also good. Furthermore, you may use the cutting insert shown in FIG. 4 for all the cutting inserts 5A-5C.

1,100 Drill head 2 Drill head body 5A Center side cutting insert 5C Intermediate side cutting insert 50 Cutting insert body 51 Cutting edge 51a (Cutting edge) Edge 52 Relief surface O Center point OL (Cutting insert body) OL (Cutting insert body) Center line G (Drill head body) Center axis P1 Drill head rotation direction P2 Cutting reaction force T1, T2 Thickness W Work material

Claims (3)

An upper surface, a lower surface and has a cutting insert body made of a planar view substantially rectangular thick plate and a side surface which is an upper surface and a lower surface integrally formed,
Each of the intersections of the upper surface and the side surface and the lower surface and the side surface form an upper surface side and a lower surface side intersecting portion made of a ridge line having a substantially rectangular shape in plan view.
Among these upper and lower surface side intersections , a straight cutting edge is formed at a pair of upper and lower surface side intersections facing each other in parallel with the center line with the center line passing through the center point of the cutting insert body as the axis of symmetry. Formed,
Furthermore, of these upper and lower surface side intersections, a center line passing through the center point of the cutting insert main body is used as a symmetry axis, and a pair of upper and lower surface side intersections perpendicular to the center line and facing each other are A flank inclined in the shape of a reverse letter from both end edges toward the center point is formed,
Furthermore, stepped chip breakers are formed on the upper surface side and the lower surface side on the side surfaces of the upper and lower surface side crossing portions where the cutting edges are provided on the upper and lower surface sides among the upper and lower surface side crossing portions. Cutting insert characterized by.   A blade body that cooperates to cut the work material is provided at each of a plurality of locations including at least the center side, the intermediate side, and the outer peripheral side of the tip surface of the cylindrical drill head body, and at least the center side blade body is A drill comprising the cutting insert according to claim 1, wherein the cutting insert is provided in a direction orthogonal to the central axis of the drill head main body when viewed from the front when the cutting insert is provided on the tip surface of the drill head main body. head.   3. The drill head according to claim 2, wherein when the cutting insert is provided on the distal end surface of the drill head main body, the drill insert is provided so as to tilt toward a proximal end side of the drill head main body.

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