KR20090044825A - High feed rotary cutting tool - Google Patents

Abstract

The present invention discloses a rotary cutting tool capable of indexing by forming cutting edges on both sides of the insert, distributing the force applied to the clamping screw to prevent breakage of the clamping screw and to firmly clamp the insert to the tool body. . In the rotary cutting tool according to the present invention, each pocket portion of the tool body is provided with a radial support wall, an axial support wall, and a rotational support wall, the axial support wall being axially formed at an acute angle with the rotation direction support wall. It is formed to be inclined with the vertical plane; Each insert has a hexahedron shape with four sides connecting trapezoidal top and bottom surfaces parallel to each other and a top and bottom surface, and having through-holes formed across each center of the top and bottom surfaces. . The first and second sides of the four sides of the insert are opposite in the radial direction and parallel to each other, perpendicular to the top and bottom surfaces respectively, and the third and fourth sides of the four sides are opposite in the axial direction. The third side and the fourth side are formed to be inclined at the same angle with respect to the vertical surface with respect to the upper surface and the lower surface, respectively. Further, a first cutting edge is formed at the boundary between the third side and the upper surface, and a second cutting edge is formed at the boundary between the fourth side and the lower surface; The lower surface is in contact with the rotational support wall, the first side is in contact with the radial support wall, and the fourth side is in contact with the inclined axial support wall, so that the second cutting edge is in contact with the axial support wall Retained at an acute corner between the walls, the first cutting edge protrudes forward of the tip of the tool body as the main cutting edge.

Rotary cutting tools, inserts, tool bodies

Description

High feed rotary cutting tool

The present invention relates to a rotary cutting tool, in particular by mounting the insert in a pocket having an inclined side wall formed in the tool body to disperse external forces applied to the insert to reduce the stress on the clamping screw and inserts to the tool body. A rotary cutting tool which can be firmly fixed.

Generally, the cutting tool comprises a tool body made of steel and an insert made of cemented carbide, the insert being detachably fixed to the tool body via a clamping screw.

In such a cutting tool, the insert having a trapezoidal cross-sectional shape is mounted to the tool body with its side obtuse to the bottom mounting surface of the tool body. In this structure, when cutting resistance is applied to the cutting edge formed at one end of the insert, it is only canceled by the clamping force by the clamping screw that fixes the insert to the tool body. Therefore, when the workpiece is processed under high feed conditions, if a large cutting force is applied to the cutting edge of the insert, excessive clamping force is applied to the clamping screw, resulting in a problem that the clamping screw is broken.

Meanwhile, conventionally, chip grooves are formed on only one surface of the upper and lower surfaces. In such a structure, if the cutting edge is worn out by the chips generated during cutting or the surface on which the chip grooves are formed is damaged, the insert itself must be replaced instead of indexing.

In order to solve the above problems, Korean Laid-Open Patent Publication No. 10-2004-0027133 discloses a cutter having a structure that can suppress the generation of vibration and firmly mount the insert to the tool body.

The insert of the cutter disclosed in Korean Patent Laid-Open Publication No. 100-2004-0027133 has a parallelogram cross section in which both parallel sides are inclined with respect to the upper and lower surfaces, and it is difficult to manufacture an insert having such a side shape.

In addition, since the insert mounted on the cutter mentioned above has a substantially square planar shape, the overall size becomes excessively small in order to mount the insert on the cutter of a small diameter, which makes manufacturing and handling difficult.

The present invention is designed to solve the above problems of the rotary cutting tool, it is possible to index by forming cutting edges on both sides of the insert, to prevent the breakage of the clamping screw by dispersing the force applied to the clamping screw It is an object of the present invention to provide a rotary cutting tool capable of firmly clamping the tool body.

Still another object of the present invention is to provide an insert shape and mounting structure suitable for small diameter rotary cutting tools while providing sufficient clamping force.

In the rotary cutting tool according to the present invention for achieving the above object, each pocket portion of the tool body is provided with a radial support wall, an axial support wall, and a rotation direction support wall, the axial support wall and the rotation direction support wall It is formed to be inclined with the surface perpendicular to the axial direction to form an acute angle; Each insert has a hexahedron shape with four sides connecting trapezoidal top and bottom surfaces parallel to each other and a top and bottom surface, and having through-holes formed across each center of the top and bottom surfaces. .

The first and second sides of the four sides of the insert are opposite in the radial direction and parallel to each other, perpendicular to the top and bottom surfaces respectively, and the third and fourth sides of the four sides are opposite in the axial direction. The third side and the fourth side are formed to be inclined at the same angle with respect to the vertical surface with respect to the upper surface and the lower surface, respectively.

Further, a first cutting edge is formed at the boundary between the third side and the upper surface, and a second cutting edge is formed at the boundary between the fourth side and the lower surface; The lower surface is in contact with the rotational support wall, the first side is in contact with the radial support wall, the fourth side is in contact with the inclined axial support wall, and the second cutting edge is in contact with the axial support wall Retained at an acute corner between the walls, the first cutting edge protrudes forward of the tip of the tool body as the main cutting edge.

Here, the upper surface is provided with a chip groove along the first cutting edge, the chip groove is formed to be inclined with respect to the upper surface toward the central axis from the outside of the tool body, the lower surface is chip groove along the second cutting edge Wherein the chip groove is formed inclined with respect to the lower surface from the tool body outline toward the central axis, the first cutting edge has a positive cutting angle with respect to the vertical surface in the axial direction.

Further, the clearance grooves are preferably formed along the boundary between the axial support wall and the rotational support wall, the boundary between the radial support wall and the axial support wall, and the boundary between the radial support wall and the rotational support wall, respectively.

The rotary cutting tool according to the present invention can be indexed by forming cutting edges on both sides of the insert, it is possible to distribute the force applied to the clamping screw to prevent breakage of the clamping screw and to clamp the insert firmly to the tool body have.

The present invention is also suitable for small diameter rotary cutting tools while providing sufficient clamping force.

Hereinafter, with reference to the accompanying drawings, a rotary cutting tool according to the present invention will be described in detail. In the following description, as an example of a rotary cutting tool according to the present invention, a drilling tool used in a drilling process will be described.

1 is a perspective view of one insert constituting a rotary cutting tool according to the present invention, FIGS. 2, 3, and 4 are plan views, front views, and side views of the insert shown in FIG. 1, illustrating the structure of the insert 100. It is shown.

The rotary cutting tool according to the present invention includes a tool body 200 and a plurality of inserts 100 interchangeably mounted to a plurality of pockets 210 formed at the tip outer peripheral portion of the tool body 200.

In the tool body 200, each pocket portion 210 has a radial support wall 211, an axial support wall 212, and a rotational support wall 213. Here, the radial direction, the axial direction and the rotation direction are set based on the rotation axis of the tool body 200, and each support wall 211, 212, 213 forms a plane substantially perpendicular to each direction. In particular, the axial support wall 212 is formed to be inclined with the surface perpendicular to the axial direction to form an acute angle with the rotation direction support wall 213.

Each insert 100 has four sides 101, 102, 103, 104 connecting trapezoidal top and bottom surfaces 106 and the top and bottom surfaces 105 and 106 that are parallel to each other. It has a hexahedron shape with). Here, the through hole 150 is formed across each central portion of the upper surface 105 and the lower surface 106.

The first side 101 and the second side 102 of the four sides of the insert 100 are opposite in the radial direction and parallel to each other and perpendicular to the upper surface 105 and the lower surface 106, respectively. Further, the third side 103 and the fourth side 104 of the four sides are opposed in the axial direction, and the third side 103 and the fourth side 104 are as shown in FIGS. 4 and 5. Likewise, the inclined surfaces are formed at the same angle with respect to the vertical surfaces of the upper surface 105 and the lower surface 106, respectively.

In this embodiment, it is preferable that the radial support wall 211 and the axial support wall 212 of each pocket portion 210 form an acute corner angle on the rotation direction support wall 213, and the insert 100 The upper and lower surfaces 105 and 106 are isosceles trapezoidal, with the first side 101 and the fourth side 104 formed on the upper side 105 and the lower side 106 and the angles of the first side ( It is preferable that the angles formed on the upper surface 105 and the lower surface 106 of the 101 and the third side surface 103 each have the same acute angle corresponding to the corner angle.

FIG. 5 is a cross-sectional view taken along line AA of FIG. 2, with grooves 131 and 132 formed on the upper surface 105 and the lower surface 106 and the first and second cutting edges 131-1, respectively; 132-1) is shown.

As shown in FIGS. 2 and 5, a first cutting edge 131-1 is formed at the boundary between the third side 103 and the upper side 105 of the insert 100, and the fourth side 104. The second cutting edge 132-1 is formed at the boundary between the lower surface 106 and the lower surface 106. On the other hand, second side 102 and third side 104 form an obtuse rounded corner portion on top surface 105 to provide corner cutting edge 131-2.

The insert 100 having the shape as described above is centered on the symmetry line (S in FIG. 1) passing through the center of the through hole 150 and the center of the first and second side surfaces 101 and 102 shown in FIG. 1. When rotated 180 degrees, the third side 103 and the fourth side 104 and the upper side 105 and the lower side 106 are interchanged with each other, but the overall shape of the insert 100 is the same as before the rotation. That is, the insert 100 is rotationally symmetrical about the axis of symmetry S. This rotational symmetry enables indexing of the insert 100.

6, 7 and 8 are a partial perspective view, side view and front view of the cutting tool of the rotary cutting tool according to the present invention, showing a state in which the insert 100 is mounted to the tool body 200. In particular, FIG. 7 shows a state in which one insert 100 is separated from the tool body 200.

The bottom surface 106 of the insert 100 is in contact with the rotational support wall 213 of the pocket portion 210, the first side 101 is in contact with the radial support wall 211, and the fourth side surface ( 104 is in contact with the inclined axial support wall 212. Thus, the second cutting edge 132-1 is retained at an acute corner between the axial support wall 212 and the rotational support wall 213, and the first cutting edge 131-1 is the tool body 200. Protrude forward of the leading edge to perform the function of the main cutting edge.

1, 2 and 3, each insert 100 includes a groove 131 formed along the first cutting edge 131-1 on the upper surface 105, and the chip groove ( 131 is formed to be inclined with respect to the upper surface 105 toward the central axis from the outside of the tool body 200.

In addition, the lower surface 106 is formed with a chip groove 132 along the second cutting edge 132-1, and the chip groove 132 has a lower surface toward the central axis from the outside of the tool body 200. It is formed to be inclined with respect to (106). Meanwhile, as shown in FIG. 7, the insert may be mounted such that the first cutting edge 131-1 has a positive cutting angle β with respect to a vertical plane with respect to the axial direction of the tool body 200.

The combination of the inclined chip groove 132 and the positive cutting angle as described above allows more smooth chip evacuation during the erase processing.

As described above, the tool body 200 rotates while the plurality of inserts 100 are mounted to the pocket portions 210 of the tool body 200, and at the same time, the cutting edge portions 131-1 of the insert 100 are rotated. Cutting into the work piece proceeds by contacting the work piece (not shown). The chip generated during cutting moves along the chip groove 131 formed on the upper surface 105 of the insert 100 and is discharged to the outside of the insert 100.

Meanwhile, a clearance groove 221 is formed along a boundary between the axial support wall 212 and the rotational support wall 213 of each pocket portion 210 of the tool body 200, and the radial support wall 211 is provided. And a clearance groove 222 is formed along the boundary of the axial support wall 212. In addition, the clearance groove 223 is formed along the boundary between the radial support wall 211 and the rotational support wall 213.

9 is a cross-sectional view taken along the line BB of FIG. 7, showing the axial support wall 212 of the pocket portion 210 of the tool body 200 and the corresponding fourth side 104 of the insert 100. ) Relationship.

As shown in FIG. 9, the cutting edge portion 132-1, which does not correspond to the workpiece in the cutting process, forms a boundary between the axial support wall 212 and the rotation direction support wall 213 of the pocket 210. Located in the clearance groove 221 formed along.

Even when vibration occurs in the insert 100 due to the cutting resistance during the cutting process, the cutting edge portion 132-2 does not contact the tool body 200 by the play groove 221, and therefore, unused cutting. The edge portion 132-2 is maintained without damage.

On the other hand, when the cutting edge portion 131-1 of the insert 100 for cutting the workpiece is worn out or the chip groove 131 formed on the upper surface 105 is damaged during the cutting process, the rotational symmetry The feature allows the insert to be indexed without replacing it with a new insert.

That is, the operator first removes the insert 100 from the tool body 200 by removing the clamping screw 300. The insert 100 is then rotated 180 degrees about the axis of symmetry (S in FIG. 1).

In this state, when the insert 100 is mounted on the pocket portion 210 of the tool body 200, a new, unworn cutting edge portion 132-1 protrudes toward the tip of the tool body 200 to cut the workpiece. It becomes a cutting edge.

In each pocket portion 210, the axial support wall 212 and the rotational support wall 213 form an acute angle a, which is the first side 101 of the insert 100. ) And the inclined fourth side 104 between the second side 102.

As shown in FIGS. 8 and 9, the cutting edge 131-1 of the insert 100 cuts the workpiece while the tool body 200 rotates (in the direction of the arrow of FIG. 8). Cutting resistance F is applied to the cutting edge portion 132-1 of 100. The reaction force against this cutting resistance F is substantially canceled by the clamping force Fc generated by the clamping screw 300.

In the insert 100 and the tool body 200 of the above structure, the vertical component of the transmission force between the inclined fourth side 104 of the insert 100 and the axial support wall 212 of the pocket portion 210 May cancel the reaction force together with the clamping force Fc by the clamping screw 300. Accordingly, excessive stress does not occur in the clamping screw 300, thereby preventing breakage of the clamping screw 300.

On the other hand, in the process of forming a vertical wall portion having a depth to the workpiece using a cutting tool, the second side surface 102 of each insert 100 can contact the wall portion of the workpiece by the bending of the rotation axis. Under these conditions, the cutting resistance is significantly increased.

In order to solve this problem, in the insert 100 constituting the cutting tool according to the present invention, as shown in Figures 1, 2, 6 and 8, the insert 100 of the tool body 200 When mounted to the pocket portion 210, a gentle recessed portion 102-1 is formed in the center portion of the second side surface 102 that is exposed to the outside. In the insert 100 of such a structure, the contact between the second side surface 102 and the processed inner wall of the workpiece can be minimized, thereby greatly reducing the cutting resistance.

As shown in Figs. 1, 2, 3 and 4, the insert 100 constituting the cutting tool according to the present invention has a lateral width (first side 101 and second side) without compromising its fastening force. The length between the side surfaces 102 can be made very small compared to its longitudinal length (the length between the third side surface 103 and the fourth side surface 104). It is particularly useful for stably mounting to the tool body 200 of the cutting tool.

In addition, since the third side surface 103 and the fourth side surface 104 where the cutting edge is not formed are perpendicular to the upper surface 105 and the lower surface 106, the third side surface 103 and the fourth side surface. The inclined portion associated with 104 is not necessary, thereby reducing the width of the insert 100 by that amount. Furthermore, this structure offers the advantage that the insert can be easily machined.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having various ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. And additions should be considered to be within the scope of the following claims.

1 is a perspective view of an insert constituting a rotary cutting tool according to the present invention.

2, 3, 4 are plan, front and side views of the insert shown in FIG.

5 is a cross-sectional view taken along the line A-A of FIG. 2.

Figure 6 is a partial perspective view of a rotary cutting tool according to the present invention, showing the tool body and the insert mounted to the tool body.

7 is a side view of the rotary cutting tool, showing a state in which one insert is separated from the tool body.

8 is a front view of a rotary cutting tool according to the invention, showing the tool body and the insert mounted to the tool body.

9 is a cross-sectional view taken along the line B-B of FIG. 7.

Claims (7)

A rotary cutting tool comprising a tool body and a plurality of inserts interchangeably mounted to a plurality of pocket portions formed at a tip outer peripheral portion of the tool body; Each pocket portion includes a radial support wall, an axial support wall, and a rotational support wall, the axial support wall being inclined with an axially perpendicular surface to form an acute angle with the rotational support wall; The inserts have a hexahedron shape having four side surfaces connecting the upper and lower surfaces and the upper and lower surfaces of the trapezoidal shape parallel to each other, and formed through each center of the upper and lower surfaces. Has a hole; The first side and the second side of the four sides are radially opposite and parallel to each other, perpendicular to the top and bottom surfaces respectively, and the third and fourth sides of the four sides are opposite in the axial direction. The third side and the fourth side are formed to be inclined at the same angle with respect to the vertical plane with respect to the upper side and the lower side, respectively, and a first cutting edge is formed at the boundary between the third side and the upper side, and the fourth side and the lower side. A second cutting edge is formed at the boundary of the face; The lower surface is in contact with the rotational support wall, the first side is in contact with the radial support wall, and the fourth side is in contact with the inclined axial support wall, so that the second cutting edge is in contact with the axial support wall Retained at an acute corner between the walls, wherein the first cutting edge protrudes forward of the tip of the tool body as the main cutting edge. 2. The radial and axial support walls of claim 1, wherein the radial and axial support walls have an acute corner angle on the rotational support wall, the top and bottom surfaces being isosceles trapezoidal, with the first and fourth sides being the top and And an angle formed on the lower surface and angles formed on the upper and lower surfaces of the first side and the third side respectively have the same acute angle corresponding to the corner angle. 3. An upper surface according to claim 1 or 2, wherein the upper surface is provided with chip grooves along the first cutting edge, the chip grooves being inclined with respect to the upper surface toward the central axis from the outside of the tool body. 2 chip grooves are provided along the cutting edge, the chip grooves being inclined with respect to the lower surface from the outside of the tool body towards the central axis, the first cutting edge having a positive cutting angle with respect to the vertical plane with respect to the axial direction. Rotary cutting tool, characterized in that. The rotary cutting tool according to claim 1 or 2, wherein a clearance groove is formed along a boundary between the axial support wall and the rotational support wall. The rotary cutting tool according to claim 1, wherein a clearance groove is formed along a boundary between the radial support wall and the axial support wall. The rotary cutting tool according to claim 1, wherein a clearance groove is formed along a boundary between the radial support wall and the rotational support wall. The rotary cutting tool according to claim 1 or 2, wherein the second side surface has a gentle recess in the center portion.

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