TECHNICAL FIELD

The present disclosure relates to a cutting insert and a cutting tool having the same mounted therein.

BACKGROUND ART

Generally, a cutting insert is fastened to a cutting tool mounted on a machine tool and is used for cutting a workpiece made of iron, non-ferrous metal, non-metal material, and so on.

Such a cutting insert has a shape such that the sides connecting the upper surface and the lower surface are rotationally symmetrical with respect to each other by 180 degrees with respect to the center thereof, and thus are broadly divided into a double-sided cutting insert that can use both upper and lower surface-side cutting edges, and a single-sided cutting insert that uses only the upper surface-side cutting edge.

As the related art, the replaceable cutting insert is disclosed in the Korean Patent Laid-Open No. 10-2009-0108905, which includes, as shown inFIG. 14, an upper surface150and a lower surface160facing each other, two longitudinal side surfaces110and120and two transverse side surfaces130and140connecting the upper surface150and the lower surface160, and a through hole190extending through the respective centers of the upper surface150and the lower surface160. For reference, the same reference numerals are used in the background art as they are used in the Korean Patent Laid-Open No. 10-2009-0108905, but the same reference numerals do not necessarily refer to the same components even if they overlap with the reference numerals used in the detailed description of the present disclosure to be described below.

However, according to the related technique described above, since each of the two longitudinal side surfaces110and120is formed as a flat surface as a whole, there is a problem that the fastening force with a seat surface is decreased due to impacts applied during cutting, which allows movements on the seat surface of the cutter200of the milling apparatus, or the like. In particular, during high-speed machining, the distribution force is large and vibration easily occurs, resulting in a problem that the fastening force with the seat surface is further reduced.

SUMMARY

Technical Problem

A technical object of the present disclosure is to provide a cutting insert capable of improving a fastening force with a seat surface, and a cutting tool having the same mounted therein.

Another technical object of the present disclosure is to provide a cutting insert capable of improving rigidity as well as fastening force, and a cutting tool having the same mounted therein.

Still another technical object of the present disclosure is to provide a cutting insert capable of improving cutting characteristics as well as fastening force, and a cutting tool having the same mounted therein.

Technical Solution

In order to achieve the above objects, a cutting insert according to an embodiment of the present disclosure is provided, which may include an upper surface and a lower surface oriented in opposite directions, a first and a second shorter side surface connecting the upper surface and the lower surface to each other and oriented in opposite directions, a first and a second longer side surfaces connecting the upper surface and the lower surface to each other, connecting the first and the second shorter side surfaces to each other, oriented in opposite directions, and being longer than the first and the second shorter side surfaces, a through hole extending through the upper surface and the lower surface, a shorter cutting edge provided at a boundary between the upper surface and the first shorter side surface, a first corner cutting edge provided at a boundary between the upper surface and a corner between the first longer side surface and the first shorter side surface, and a second corner cutting edge provided at a boundary between the upper surface and a corner between the second longer side surface and the first shorter side surface, in which, when viewed toward the upper surface, the first longer side surface may have two side portions, each side portion having an inclined shape with reference to the center portion.

In one example, when viewed toward the upper surface, first longer side surface may have a shape such that the center portion thereof is convexly protruded.

When viewed toward the upper surface, the first longer side surface may include a convex portion which is convexly protruded and which forms a center portion, first and second inclined sections forming both sides with reference to the convex portion and gradually inclined toward an inside of the upper surface as further away from the convex portion, and first and second concave portions which are concavely recessed and which form end portions of the first and second inclined sections.

When viewed in a section cut along a vertical direction from the upper surface to the lower surface, the first longer side surface may form a vertical angle with the upper surface.

When viewed toward the upper surface, the first shorter side surface may have an outwardly convex shape, and one side with reference to a center portion of the first shorter side surface may form an acute angle with one of the inclined sides of the first longer side surface.

When viewed toward the upper surface, the first shorter side surface may have a curved shape as a whole or a shape that combines a curved line and a straight line.

When viewed toward the first shorter side surface, the shorter cutting edge may have a curved shape as a whole or a shape that combines a curved line and a straight line.

In one example, when viewed toward the first shorter side surface, the first corner cutting edge may be positioned higher than the second corner cutting edge, and the highest portion of the shorter cutting edge may be positioned closer to the first corner cutting edge than the second corner cutting edge.

In another example, when viewed toward the first shorter side surface, the first corner cutting edge may be positioned lower than the second corner cutting edge, and the highest portion of the shorter cutting edge may be positioned closer to the second corner cutting edge than the first corner cutting edge.

In still another example, when viewed toward the first shorter side surface, the first and second corner cutting edges may be positioned at the same height, and the highest portion of the shorter cutting edges may be positioned closer to the center than the first and second corner cutting edges.

When viewed toward the first longer side surface, the first shorter side surface may form a vertical angle with the upper surface.

When viewed toward the upper surface, the shorter cutting edge may have a curved shape that is outwardly convex.

In another example, when viewed toward the upper surface, the first longer side surface may have a shape such that a center portion thereof is concavely recessed.

When viewed toward the upper surface, the first longer side surface may include a concave portion which is concavely recessed and which forms a center portion, and first and second inclined sections forming both sides with reference to the concave portion and being gradually inclined as further away from the concave portion outward the upper surface.

When viewed toward the upper surface, each of the first and second inclined sections may have a straight shape.

In one example, the upper surface may be rotationally symmetrical by 180 degrees with respect to a center thereof.

In another example, the upper surface and the lower surface may have the same shape as each other, each of the upper and lower surfaces may be rotationally symmetrical by 180 degrees with respect to a center thereof, each of the first and second shorter side surfaces may be rotationally symmetrical by 180 degrees with respect to a center thereof, and each of the first and second longer side surfaces may be rotationally symmetrical by 180 degrees with respect to a center thereof.

Meanwhile, a cutting tool according to an embodiment of the present disclosure is a cutting tool having, mounted therein, the cutting insert according to the embodiments of the present disclosure described above, which may include a first seat surface on which the lower surface is placed, a second seat surface on which the first longer side surface is placed, and a third seat surface on which the first shorter side surface is placed, in which the second seat surface may have a first longer side inclined surface and a second longer side inclined surface on which the inclined both sides of the first longer side surface may be respectively seated.

The third seat surface may include a shorter side inclined fastening surface on which the one side of the first shorter side surface is seated and which is adjacent to an outer circumferential surface of the cutting tool, and the shorter side inclined fastening surface may form an acute angle with any one of the first longer side inclined fastening surface and the second longer side inclined fastening surface.

Advantageous Effects

A cutting insert according to the present disclosure having the configuration as described above and a cutting tool having the same mounted therein may have the following effects.

The technical configuration of the cutting insert according to the present disclosure includes an upper surface, a lower surface, first and second shorter side surfaces, first and second longer side surfaces, and a through hole extending through the upper and lower surfaces, in which, when viewed through the upper surface, the first longer side has a shape such that both sides thereof are inclined with reference to a center portion thereof, so that the inclined both sides are in close contact with the sheet surface of the cutting tool, and accordingly, the fastening force with the sheet surface of the cutting tool can be improved during cutting.

In addition, the cutting insert according to the present disclosure has a shape such that, when viewed toward the upper surface, a center portion of the first longer side surface is convexly protruded, so that the through hole and the cutting tool fastening bolt inserted therein can be formed with a relatively large diameter, and accordingly, the fastening force with the cutting tool can be further improved.

In addition, according to the technical configuration of the cutting insert according to the present disclosure, when viewed toward the upper surface, the first longer side surface has an outwardly convex shape and one side thereof with reference to the center portion of the first longer side surface forms an acute angle with one of the inclined both sides of the longer side surface, and accordingly, the fastening force with the cutting tool can be further improved.

In addition, according to the cutting insert of the present disclosure, when viewed toward the first longer side surface, the first longer side surface forms a vertical angle (so-called negative type) with the upper surface so that, as compared with when the acute angle (so-called positive) is formed therebetween, the rigidity of the shorter cutting edge provided at the boundary between the upper face and the first longer side surface can be increased.

In addition, according to the cutting insert of the present disclosure, when viewed toward the upper surface, the first longer side surface has a shape such that a center portion thereof is concavely recessed so that the sheet surface of the cutting tool can be protruded as much as the concave recess, that is, the web size of the cutting tool can be increased, and accordingly, the rigidity of a holder of the cutting tool can be improved.

Further, according to the technical configuration of the cutting insert of the present disclosure, when viewed toward the first longer side surface, the shorter cutting edge has a curved shape or a shape that combines a curved line and a straight line, and also a curved shape that is outwardly convex when viewed toward the upper surface, so that the shorter cutting edge has an approximately helix edge structure, and accordingly, the cutting characteristics for the shorter cutting edge can be improved, and the cutting load on the shorter cutting edge can be reduced.

Meanwhile, the present disclosure may have other effects that can be derived from the configuration according to the present disclosure in addition to the effects described above.

