| JP2004148498 | INDEXABLE TURNING TOOL |
| JP2003159601 | MULTIFUNCTIONAL CUTTING TOOL AND LATHE USING THE SAME |
| JP2007000976 | MULTI-FUNCTIONED TOOL |
LEE, Young Bae (603-702, Doosan Apt.Pung-dong, IlsanDong-gu, Goyang 410-330, KR)
| Claims
[ 1 ] L A drill insert comprising: a chisel for setting a center point of a hole at a cutting object when the hole is machined; a cutting edge for cutting the cutting object during rotation thereof; and multiple web thinning parts having at least two cutting edges disposed opposite to each other with the chisel interposed therebetween to make the cutting object in point contact with the chisel.
[2] The drill insert according to claim 1 , wherein the multiple web thinning parts have an edge in contact with the cutting object, and the edge has a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape.
[3] The drill insert according to claim 1, wherein, in the multiple web thinning parts, one web thinning part adjacent to the chisel has a straight edge in contact with the cutting object, and other web thinning parts have a curved edge to readily discharge generated chips.
[4] The drill insert according to claim 1, wherein the multiple web thinning parts comprise: a first web thinning part disposed relatively far from the chisel and having a curved edge in contact with the cutting object; and a second web thinning part disposed at a portion of the first web thinning part to be in contact with the chisel and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape.
[5] The drill insert according to claim 1, wherein the multiple web thinning parts comprise: a first web thinning part disposed relatively far from the chisel and having a straight edge in contact with the cutting object; and a second web thinning part disposed at a portion of the first web thinning part to be in contact with the chisel and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape.
[6] The drill insert according to claim 1 , wherein the multiple web thinning parts comprise: a first web thinning part disposed relatively far from the chisel and having an edge in contact with the cutting object, the edge having a shape that is a combination of a curved shape and a straight shape; and a second web thinning part disposed at a portion of the first web thinning part to be in contact with the chisel and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape.
[7] The drill insert according to claim 1, wherein the multiple web thinning parts comprise: a first web thinning part disposed relatively far from the chisel and having a curved edge in contact with the cutting object; a second web thinning part disposed at a portion of the first web thinning part and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape; and a third web thinning part disposed at a portion of the second web thinning part to be in contact with the chisel and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape.
[8] The drill insert according to claim 1, wherein the multiple web thinning parts comprise: a first web thinning part disposed relatively far from the chisel and having a straight edge in contact with the cutting object; a second web thinning part disposed at a portion of the first web thinning part and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape; and a third web thinning part disposed at a portion of the second web thinning part to be in contact with the chisel and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape.
[9] The drill insert according to claim 1 , wherein the multiple web thinning parts comprise: a first web thinning part disposed relatively far from the chisel and having an edge in contact with the cutting object, the edge having a shape that is a combination of a curved shape and a straight shape; a second web thinning part disposed at a portion of the first web thinning part and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape; and a third web thinning part disposed at a portion of the second web thinning part to be in contact with the chisel and having an edge in contact with the cutting object, the edge having a shape selected from a curved shape, a straight shape, and a combination of the curved shape and the straight shape. |
Description DRILL INSERT
Technical Field
[1] The present invention relates to a drill insert, and more particularly, to a drill insert as an expendable cutting tool detachably coupled to a tip of a drill. Background Art
[2] Generally, a drill insert is classified, depending on its shape, as a spade drill insert, a helical thinning insert, a U-drill insert, and so on. Such a drill insert is an expendable cutting tool fixedly coupled to a tip of a drill as a cutting tool by screws, and then exchanged with a new one after tens or hundreds of cutting operations.
[3] The drill insert functions to bring a chisel in direct contact with a surface of a cutting object during initial cutting operation, to position a center point of the cutting operation, to maintain the center point during the cutting operation, and to cut the cutting object at the center point of the cutting tool. The conventional drill insert will be described with reference to the accompanying drawings.
[4] FIG. 1 is a perspective view of a conventional spade drill insert, and FIG. 2 is a perspective view of the spade drill insert to be coupled to a drill.
[5] Referring to FIGS. 1 and 2, the conventional spade drill insert includes a body 100 having a predetermined thickness, primary relief surfaces 110 inclined outward to form an apex at a center of one surface, and first and second pentagonal surfaces 101 and 102, race surfaces 120 disposed at portions of the first and second surfaces to cut a cutting object along the primary relief surfaces when the body 100 is rotated, secondary relief surfaces 130 inclined at portions of the primary relief surfaces 110, at which the race surfaces are not disposed, web thinning parts 140 grooved toward the apex of the primary relief surfaces from the race surfaces 120, and fastening holes 150 for fastening the body 100 to a drill 200 using bolts.
[6] Reference numeral 160 designates a key way coupled to the drill 200, and reference numeral 170 designates chip splitters for dividing chips into predetermined sizes.
[7] Hereinafter, structure and operation of the conventional spade drill insert will be described in detail.
[8] First, the body 100 has the first and second pentagonal surfaces 101 and 102. The pentagonal shape is formed of a rectangular shape, one long side of which projects to form an apex at its center part. In this case, two inclination surfaces about the apex are referred to as the primary relief surfaces 110.
[9] The primary relief surfaces 110 are elements constituting cutting edges, and an angle between the primary relief surfaces 110 about the apex is about 140.
[10] The race surfaces 120 as grooves are formed at the first and second surfaces 101 and 102 of the body 100 to adjoin to the primary relief surfaces 110. When seen from a side view, the race surfaces 120 have a semi-circular groove shape. Interfaces between the race surfaces 120 and the primary relief surfaces 110 constitute cutting edges 121 for actually cutting a cutting object.
[11] The race surfaces 120 are formed only at positions where a cutting object is cut in a rotational direction of the drill 200. That is, each of the first and second surfaces 101 and 102 of the body 100 has one race surface.
[12] The secondary relief surfaces 130 are formed at portions of the primary relief surfaces 110 at which the race surfaces 120 are not formed, by cutting corner parts between the upper and lower surfaces of the body 100 adjacent to each other.
[13] The secondary relief surfaces 130 have areas that are reduced toward the apex of the primary relief surfaces 110. The secondary relief surfaces 130 are configured to increase a surface area and reduce a contact surface with a wall surface of a hole, thereby more effectively discharging heat generated when the cutting is performed.
[14] In addition, the web thinning parts 140 are grooved in the race surfaces 120 adjacent to the apex of the primary relief surfaces 110 in a direction toward the apex. The web thinning parts 140 provide spaces for reducing propulsion during the cutting and discharging chips generated from a cutting object.
[15] In this formation, an edge between the web thinning parts 140 disposed at the first and second surfaces 101 and 102 is referred to as a chisel 141. The chisel 141 is in contact with a surface of a cutting object during the cutting. When the body 100 fastened to the drill 200 is rotated, the chisel 141 is rotated in a state in direct contact with the surface of the cutting object to set a center point of the cutting.
[16] A small thickness of the chisel 141 decreases propulsion and facilitates self- centering during the cutting. However, since the conventional drill insert uses a relatively long chisel 141 which relatively increases propulsion, a hole may be enlarged due to bad self-centering.
[17] In order to reduce the thickness of the chisel 141, the depth of the web thinning parts 140 should be increased. However, the large depth of the web thinning parts 140 increases an area thereof, and the increased area reduces the width of the primary relief surfaces 110 supporting the cutting edges 142 of the web thinning parts, thereby failing to maintain sufficient strength during the cutting. As a result, it is difficult to deeply form the web thinning parts 140.
[18] In addition, since the shape of the interface edge should be designated as one when the web thinning parts 140 are manufactured, the conventional drill insert is manufactured for use on a hard or soft cutting object such that a user must select a hard or soft drill insert depending on the type of the cutting object.
Disclosure of Invention
Technical Problem
[19] In order to solve the foregoing and/or other problems, it is an aspect of the present invention to provide a drill insert capable of accomplishing optical web thinning parts depending on difference between a load and a cutting amount according to a distance from a center point of the cutting, and reducing the thickness of a chisel.
[20] It is another aspect of the present invention to provide a drill insert capable of being adapted to a cutting object, regardless of hardness of the cutting object. Technical Solution
[21] The foregoing and/or other aspects of the present invention may be achieved by providing a drill insert including: a chisel for setting a center point of a hole of a cutting object when the hole is formed; a cutting edge for cutting the cutting object during rotation; multiple web thinning parts disposed at surfaces opposite to each other with the chisel interposed therebetween and minimizing the thickness of the chisel to make the cutting object in point contact with the chisel. Advantageous Effects
[22] According to the present invention, chips generated due to a difference of cutting amounts depending on distances from a center point of cutting can be effectively discharged to increase cutting efficiency and reduce damage to a drill insert due to friction with the chips, thereby increasing lifespan of the drill insert.
[23] In addition, the drill insert of the present invention includes multiple web thinning parts to reduce the thickness of a chisel and facilitate self-centering, thereby reducing propulsion and preventing a hole from being enlarged.
[24] Further, the multiple web thinning parts are configured to appropriately cut objects having different hardness, regardless of the hardness of the objects, thereby improving manufacturing and use convenience. Brief Description of the Drawings
[25] The above and other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings of which:
[26] FIG. 1 is a perspective view of a conventional spade drill insert;
[27] FIG. 2 is a perspective view of the space drill insert to be coupled to a drill;
[28] FIG. 3 is a perspective view of a drill insert in accordance with a first exemplary embodiment of the present invention;
[29] FIGS. 4 to 7 are views showing edge shapes of a first web thinning part 40 and a second web thinning part 50 of FIG. 2;
[30] FIG. 8 is a perspective view of a drill insert in accordance with a second exemplary
embodiment of the present invention; [31] FIG. 9 is a view of a modified drill insert of in accordance with a second exemplary embodiment of the present invention; [32] FIG. 10 is a perspective view of a drill insert in accordance with a third exemplary embodiment of the present invention; [33] FIG. 11 is a table representing test conditions and results of the drill insert of the present invention and a conventional drill insert; [34] FIG. 12 shows photographs showing fused levels before and after tests using the drill insert of the present invention, products of competitors, and existing goods of our company; [35] FIG. 13 is a graph in which a product having a dual web thinning part of the present invention, products of competitors, and existing goods of our company; and [36] FIG. 14 is a table representing cutting loads of a drill insert of the present invention, products of competitors, and existing goods of our company. [37] * Description of Major Reference Numerals*
[38] 1, 2: Body 10: Primary relief surface
[39] 11: First surface 12: Second surface
[40] 20: Race surface 21 : Cutting edge
[41] 30: Secondary relief surface 40, 4, 7: First web thinning part
[42] 50, 5, 8: Second web thinning part 51, 9: Chisel
[43] 60: Fastening hole 6: Third web thinning part
Best Mode for Carrying Out the Invention [44] In order to accomplish aspects of the present invention, a drill insert includes: a chisel for setting a center point of a hole of a cutting object when the hole is formed; a cutting edge for cutting the cutting object during rotation; multiple web thinning parts disposed at surfaces opposite to each other with the chisel interposed therebetween and minimizing the thickness of the chisel to bring the cutting object in point contact with the chisel.
Mode for the Invention [45] Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings. [46] FIG. 3 is a perspective view of a drill insert in accordance with a first exemplary embodiment of the present invention. [47] Referring to FIG. 3, the drill insert in accordance with a first exemplary embodiment of the present invention includes a body 1 having a predetermined thickness, primary relief surfaces 10 inclined outward to form an apex at a center of one surface, and first and second pentagonal surfaces 11 and 12, race surfaces 20
disposed at portions of the first surface 11 and the second surface 12 to cut a cutting object along the primary relief surfaces when the body 1 is rotated, secondary relief surfaces 30 inclined at portions of the primary relief surfaces 10, at which the race surfaces 20 are not disposed, first web thinning parts 40 grooved toward the apex of the primary relief surfaces 10 from the race surfaces 20, fastening holes 60 for fastening the body 1 to a drill using bolts, and second web thinning parts 50 grooved toward the apex of the primary relief surfaces 10 from a portion of the first web thinning part 40.
[48] Hereinafter, structure and operation of the drill insert in accordance with a first exemplary embodiment of the present invention will be described in detail.
[49] First, the first and the second surfaces 11 and 12 of the body 1 have a pentagonal shape, and the primary relief surfaces 10 are located about the apex. In this case, the primary relief surfaces 10 constitute a cutting edge.
[50] In addition, the race surfaces are disposed as grooves along the first and second surfaces 11 and 12 of the body 1 to be in contact with the primary relief surfaces 10. When seen from a side view, the race surfaces 20 have a semi-circular shape. A cutting object is cut by cutting edges 21, and chips are discharged along the semi-circular grooves provided at the race surfaces 20.
[51] The secondary relief surfaces 30 are disposed at the primary relief surfaces 10, at which the race surfaces 20 are not formed, by cutting corners between the first and second surfaces 11 and 12. The secondary relief surfaces 30 have an area that is increased toward the apex of the primary relief surfaces 10 to readily discharge heat therefrom.
[52] The first web thinning parts 40 and the second web thinning parts 50, as a multiplicity of grooves, are positioned at the race surfaces 20 adjacent to the apex of the primary relief surfaces in a direction toward the apex.
[53] A chisel 51 disposed between the second web thinning parts 50 has a thickness that is less than a thickness in a case in which the second web thinning parts 50 are not formed. Reduction in the thickness of the chisel 51 facilitates positioning of a center point of machining when a hole is formed, thereby reducing propulsion.
[54] In addition, the first web thinning parts 40 function as a chip pocket to facilitate discharge of chips cut from the second web thinning parts 50, and to distribute a cutting load at a point of the second web thinning parts 50, thereby protecting the chisel 51 to prevent reduction in lifespan.
[55] FIGS. 4 to 7 are views showing edge shapes of the first web thinning parts 40 and the second web thinning parts 50 of FIG. 2.
[56] In FIG. 4, edges between the first web thinning parts 40 and the primary relief surfaces 10 have a curved shape with a predetermined radius of curvature, while the
second web thinning parts 50 formed at the first web thinning parts 40 formed as grooves toward the chisel 51 have straight edges.
[57] A difference in shape of the first web thinning parts 40 and the second web thinning parts 50 is to complement a difference in cutting speed, cutting amount, and moment depending on a distance from the apex to the cutting edge of the thinning part. As the distance becomes short, the thinning parts should have a shape such that the cutting amount of the cutting edge is reduced, the cutting speed is low, and cutting can be stably performed during centering. As the distance becomes long, the thinning parts should have a shape such that the cutting amount of the cutting edge is increased, the cutting speed is high, and cutting can be performed to overcome the moment.
[58] The first web thinning parts 40 and the second thinning parts 50 are configured to cut the hard and soft cutting objects, respectively, such that the same drill insert can be used regardless of the hardness of the cutting objects.
[59] FIG. 5 is a view of an example in which both the first web thinning parts 40 and the second web thinning parts 50 have a curved shape, FIG. 6 is a view of an example in which the first web thinning parts 40 have a straight shape and the second web thinning parts 50 have a curved shape, and FIG. 7 is a view showing an example in which both the first web thinning parts 40 and the second web thinning parts 50 have a straight shape.
[60] As an optimal embodiment, as shown in FIG. 4, the first web thinning parts 40 may have a curved shape such that the second web thinning parts 50 can smoothly function as a chip pocket for discharging chips.
[61] As described above, it is possible to develop the drill insert representing different cutting characteristics depending on shapes of the first web thinning parts 40 and the second web thinning parts 50.
[62] FIG. 8 is a perspective view of a drill insert in accordance with a second exemplary embodiment of the present invention.
[63] Referring to FIG. 8, the drill insert in accordance with a second exemplary embodiment of the present invention includes a plurality of web thinning parts 4, 5 and 6.
[64] That is, second web thinning parts 5 are formed at first web thinning parts 4 by machining grooves having a predetermined angle using a cutting wheel (not shown). Then, third web thinning parts 6 are formed at portions of the second web thinning parts 5 to have a predetermined angle and a predetermined thickness adjacent to a chisel 51.
[65] Edges of the first to third web thinning parts 4, 5 and 6 may have a curved shape or a straight shape as shown in FIGS. 4 to 7.
[66] That is, the first web thinning parts 4 and the second web thinning parts 5 may have
curved edges, and the third web thinning parts 6 may have straight edges.
[67] On the other hand, the first web thinning parts 4 may have straight edges, the second web thinning parts 5 may have curved edges, and the third web thinning parts 6 may have straight edges. The edges may also be formed opposite to the above.
[68] In addition, the first web thinning parts 4 and the second web thinning parts 5 may have straight edges or curved edges, respectively, or each of the first and second web thinning parts may have a straight edge and a curved edge with the apex interposed therebetween as shown in another embodiment of the web thinning parts of FIG. 6, that is, a mixed type of the straight edge and the curved edge.
[69] As described above, the drill insert in accordance with the present invention may include a plurality of web thinning parts, and the web thinning parts may have straight edges, curved edges, or mixed edges such that an appropriate drill insert can be used depending on the kinds of cutting objects.
[70] The chisel 51 disposed between the third web thinning parts 6 has a very small thickness, and chips cut by the third web thinning parts 6 are discharged through the second web thinning parts 5 and the first web thinning parts 4. At this time, in order to readily discharge the chips, the second web thinning parts 5 and the first web thinning parts 4 may have curved edges.
[71] The web thinning parts having curved edges can readily discharge chips, in comparison with the straight edges, since the chips are rolled along the curved surface in small increments.
[72] In addition, the second web thinning parts 5 have a cutting amount larger than that of the third web thinning parts 6, and the first web thinning parts 4 have a cutting amount larger than that of the second web thinning parts 5. Therefore, in order to readily discharge the chips during the cutting, the web thinning parts adjacent to the chisel are configured to have an area and a cutting space smaller than that of the web thinning parts away from the chisel.
[73] That is, the third web thinning parts 6 have the smallest area and cutting space, and the first web thinning parts 4 have the largest area and cutting space.
[74] FIG. 10 is a perspective view of a drill insert in accordance with a third exemplary embodiment of the present invention.
[75] Referring to FIG. 10, different from the first and second embodiments, the third embodiment in accordance with the present invention includes a body 2 having a different shape.
[76] A multiple web thinning parts may be adapted to the drill insert, regardless of the body shape.
[77] That is, it is possible to reduce the thickness of the chisel 9 by forming the first web thinning parts 7 and the second web thinning parts 8. At this time, the first web
thinning parts 7 function as chip pockets for discharging chips cut by the second web thinning parts 8 and function to cut the cutting object at their edges.
[78] The first web thinning parts 7 have an area larger than that of the second web thinning parts 8. Each of the first web thinning parts 7 and the second web thinning parts 8 may be manufactured to have one selected from curved edges, straight edges, or mixed edges.
[79] As described above, the second web thinning parts 8 are formed at the first web thinning parts 7 to reduce the thickness of the chisel 9 such that the chisel 9 can be in point contact with a surface of the cutting object. As a result, since a center point of a hole can be more rapidly set when the hole is formed, it is possible to prevent the hole from being enlarged due to reduction in propulsion.
[80] In addition, since the chisel 9 is in point contact with the cutting object, it is possible to minimize generation of heat due to friction and improve heat discharge characteristics through increase in area of the multiple web thinning parts.
[81] While the third embodiment illustrates and describes an indexable insert having two web thinning parts, an indexable insert having three web thinning parts can be manufactured as described in the second embodiment, and description thereof will not be repeated.
[82] As described above, the present invention can employ the multiple web thinning parts regardless of the body shapes, vary cutting conditions using the multiple web thinning parts, and machine a hole more stably.
[83] FIG. 11 is a table representing test conditions and results of the drill insert of the present invention and a conventional drill insert.
[84] Referring to FIG. 11 , in the test, a plurality of holes were machined using the respective drill inserts under the same conditions in size, rpm, pressure, and so on.
[85] Based on results of the test, it can be seen that the drill insert in accordance with the present invention has best characteristics in wearing-resistance, load, and edge state. The respective test results will be described below with reference to photographs corresponding thereto.
[86] FIG. 12 shows photographs showing fused levels before and after tests using the drill insert of the present invention, products of competitors, and existing goods of our company.
[87] Referring to FIG. 12, it can be seen that the web thinning parts in accordance with the present invention showed the best edge state, and the test for the products of the competitors were stopped since their edges were worn in the middle of the test making it impossible to machine a hole.
[88] As described above, it is possible to reduce damage to the edge and increase lifespan of the drill insert using the multiple web thinning parts in accordance with the
present invention.
[89] FIG. 13 is a graph in which a product having a dual web thinning part of the present invention, products of competitors, and existing goods of our company.
[90] Referring to FIG. 13, while the web thinning parts in accordance with the present invention showed an initial wearing amount larger than that of the other two products, the wearing amount of the present invention was continuously reduced to show the smallest wearing amount as the machining was performed.
[91] The products of the competitors could not be tested after the middle of the test, making it impossible to measure the wearing amount.
[92] FIG. 14 is a table representing cutting loads of a drill insert of the present invention, products of competitors, and existing goods of our company.
[93] Referring to FIG. 14, it can be seen that the present invention showed the same spindle when a first hole is machined and when a final hole is machined, the spindle of the competitor's products gradually increased, and a load in a z-axis increased such that a margin part (edge) was readily worn.
[94] Therefore, it can be seen that a center point of a hole can be rapidly set using the multiple web thinning parts in accordance with the present invention, and the chips can be readily discharged to reduce a load, thereby reducing a wearing degree, in comparison with the competitor's products having a larger load. Industrial Applicability
[95] As can be seen from the foregoing, multiple webs are applied to a drill insert in accordance with the present invention to implement an appropriate thinning shape due to a difference in cutting speed, cutting amount, and moment caused by a distance from an apex to a cutting edge of the thinning part, thereby performing optimal drilling. In addition, since a center point can be readily set during the cutting by reducing the thickness of a chisel, it is possible to increase hole machining stability, to decrease propulsion, prevent generation of heat, prevent the hole from being enlarged, and smoothly discharge chips.
[96] The forgoing description concerns an exemplary embodiment of the invention, is intended to be illustrative, and should not be construed as limiting the invention. Many alternatives, modifications, and variations within the scope and spirit of the present invention will be apparent to those skilled in the art.