DE102008029404A1 - Insertion element for drilling tool, particularly spiral drill, is made of non-machined hard metal and ceramic, where completely shaped cutting edge is provided with cutting geometry to form non-machined shaping medium - Google Patents

Abstract

The insertion element (1) is made of non-machined hard metal and ceramic, where a completely shaped cutting edge (2) is provided with a cutting geometry (3) to form a non-machined shaping medium. The insertion element is powder-metallurgical made of tungsten carbide powder or ceramic powder by sintering. A cutting side (6) is provided with the cutting edge, where the cutting edge has two cutting arms. Independent claims are included for the following: (1) a drilling tool; (2) a method for manufacturing an insertion element; and (3) a method for final cutting assembly of a drilling tool, particularly in a spiral drill.

Description

The The invention relates to an insert element for a drilling tool, in particular a twist drill, wherein the insert chipless from tungsten carbide and / or ceramic is made. The invention further relates to a Drilling tool with the insert element.

such Insert elements made of hard metal and / or ceramic are well known. They are usually made in a receptacle without being made without a chip Fixed drilling tool. A desired cutting geometry becomes Ground in situ.

Of the Invention is based on the object, an insert element of the above To provide said type, which is less expensive to produce. Furthermore, by means of the insert element a possible cutting line of the drilling tool elevated and an improved bore can be achieved.

The Asked object is inventively achieved in that the insert element with a fully formed, a cutting edge having cutting geometry provided by the non-cutting Shaping is made together with the insert element.

It Thus, a cutting geometry is provided, which alone by means of chipless Shaping is made together with the insert element. she does not need any usual Post-processing before insertion into the intended drilling tool. she also requires no usual Post-processing in operational position in the intended drilling tool, which is usually done by grinding the cutting geometry. The cutting geometry is immediate with the non-cutting production made of the insert element. This by means of chipless shaping generated cutting geometry is with insertion of the insert element Ready to cut in the drill to full extent. It does not need any further cutting shaping by grinding, such as grinding of surfaces and grinding in of cutting geometries. Thanks to the immediate chipless Production of the cutting geometry can, as explained in more detail below, also very complex shapes of the cutting geometry are produced, which, after current knowledge, not by post-processing before insertion and / or after inserting a usual Insert element in the provided drilling tool by means of grinding possible are. For this would have to very fine-shaped grinding tools are used, which, due of the hard metal and / or the ceramic as hard to be processed Material exposed to extreme workloads. Further would be because the usually small dimensions of the cutting geometries extraordinarily exact and largely play-free guidance of the grinding tools necessary. This also requires a very experienced specialist. Thanks to the non-cutting cutting geometry, in one operation, the non-cutting shaping, an insert element with complete cutting geometry be prepared, the cutting geometries introduced via the molds become. these can for example via computer simulation calculated and computer supported be introduced into the molds. Thus even complex cutting geometries can be exact be created, the desired can be adapted to the intended use.

The Non-cutting production is preferably carried out by powder metallurgy. For this can the insert element of hard metal powder and / or ceramic powder by means Sintering can be produced. As carbides and / or ceramics come usual materials into consideration. Here you can for example, areas of ceramic cutting geometry and such the one for one Holder of the insert element are provided in the drilling tool, be made of carbide.

There the cutting geometry of the insert element solely by sintering in an operation is made with the insert element itself, Thus, the insert element with a much more complex and about that In addition, more accurate cutting geometry than conventional insert elements provided become. This leads, as our own experiments showed, in terms of, among other things drilling speed, Drilling temperature and service life to much cheaper values than one usual Insert member.

Preferably the insert element has a cutting side with the cutting edge on. This cutting side expediently has the intended feed direction.

In the drilling tool can be provided several insert elements. These can with respect to a designated axis of rotation of the drilling tool rotationally symmetrical with the axis of rotation as a fulcrum be arranged, wherein the cutting edges of the insert elements in their longitudinal extension are preferably aligned radially to the axis of rotation. The insert elements can be arranged equidistantly from the axis of rotation.

The cutting edge itself may have at least two cutting arms, which are rotationally symmetrical to each other with respect to a geometric center in the longitudinal direction of the cutting side as a fulcrum over a rotational angle. It may be the same fulcrum in the insert position of the insert element in a rotating drilling tool on the axis of rotation. Preferably, the Cutting side in the insert position of the insert element arranged in a drilling tool at least predominantly in and perpendicular to a provided feed direction of the drilling tool.

Preferably are the cutting arms with respect the rotation angle equally spaced from each other. At a potential Rotation angle of 120 ° can the cutting edge three cutting arms, with a possible rotation angle of 90 ° four cutting arms and at a possible Rotation angle of 60 ° six Have cutting arms. This cutting geometry can be, for example be provided in a drill head of a dental drill.

Preferably a cutting geometry is provided in which the rotation angle is 180 °. Consequently can the cutting arms with respect the longitudinal extent the cutting side or the pivot point opposite each other be arranged. With that you can the cutting arms point-symmetrical with the pivot point as Spieglungselement be arranged.

Preferably go over the cutting arms in the fulcrum into each other. Consequently The insert element can also be in the middle region of its cutting side cutting action, which, as further explained below, a Drilling capacity increased.

Advantageous can therefore also be over the middle extending cutting of material from the to be worked surface take place, whereby an increased central drilling pressure at the bottom of the material to be machined avoided can be. It can be the drilling pressure usually by a back pressure due to not cut material, often centered bez. in a middle area with the axis of rotation of the drilling tool, be greatly increased. As is known, can an elevated one Drilling pressure too undesirable temperature increases at the bottom, to elevated Tool wear, at only low possible feed rates, for running the drilling tool and / or chipping on the exit side of the workpiece to be machined to lead, at which the drilling tool emerges when drilling through the workpiece. Spalling can also occur with blind holes. With omission or humiliation the dynamic pressure can be a corresponding reduction of the Bohrdruckes be achieved.

The Insert element can in a conventional form be designed as an insert plate. The insert plate can be two huge, mutually parallel side surfaces and one in use position in the recording of the drilling tool in the feed direction have rear, designed as a cutting side narrow side.

Preferably is provided that the cutting edge over the entire longitudinal extent of Cutting side runs. With the arrangement of the cutting edge over the entire longitudinal extent of the Cutting side can over the entire longitudinal extent the cutting side a corresponding cutting action can be achieved. Thus, a possible Cutting performance in particular by means of more complete cutting compared to conventional insert elements of material at the bottom of the hole, increased feed speed and / or lowered temperature at the bottom of the well under possible simultaneous increase the service life of the insert element bez. of the drilling tool with be increased to the insert element

Is appropriate the narrow side in use position of the insert element in a drilling tool at least predominantly perpendicular to a designated feed direction of the drilling tool arranged.

Another advantage is considered when in the cutting direction of the cutting edge at each or almost every section of the cutting edge in its longitudinal extent a free space ( 12 ) for receiving cut chips and / or separated drill dust adjoins.

In the free space cut chips or pieces of the material to be processed and collected by another Arrangements, such as the provision of so-called ejection grooves, from the bottom of the hole be transported away. Due to the fact that in the cutting direction of Cutting edge on each or almost every section of the cutting edge in their longitudinal extension a free space connects and the chips and / or the drilling dust from the place of their formation in a free space can be cut into can the dynamic pressure and thus the drilling pressure at the bottom of the work to be machined Materials are further degraded.

In a development of the insert element can be provided that the cutting edge over her Course in longitudinal extension Discontinuities and / or interruptions.

These discontinuities may be, for example, angle changes with respect to an angle which the cutting edge encloses in its longitudinal extension with a feed direction provided in the insertion position. This can lead, for example, to a peak formation with tips pointing in the feed direction. The cutting edge may also be interrupted, whereby it is divided into preferably longitudinally spaced sections. These discontinuities and / or interruptions, depending on their size and / or the material to be separated, may result in breakage of a chip that is just in a discontinuous position and / or interruption is separated from the bottom of the well. The greater the angle change, the easier it can be to break a chip. With the chipbreaker a medium chip size can be reduced, which facilitates a continuation of cut chips from the bottom of the hole.

The Cutting geometry can be used in a further development of the insert element have two main cutting edges. These can with respect to the longitudinal extent of the cutting side equidistant from a geometric center of the cutting side be arranged. Furthermore, each main cutting edge can rotate in the direction of rotation behind the main cutting a clearance with a Spanauswurfnut for cut off Chips and / or Connect separated drill dust. This will be a possible Back pressure due to shavings cut by the main cutting edges at least reduced.

The Main cutting can in terms of their longitudinal extent each have a sickle-like course, wherein the curvature in provided cutting direction of the associated main cutting points. Thus, you can the main cutting edges regarding the body of the insert element have a concave curvature. By the curved Course is advantageously increased the actual length of the cutting edge. through of the curved one History can in the cutting direction of the main cutting behind each the same one opposite a usual one straight course of the main cutting enlarged clearance provided become. This enlargement of the Free space can in turn, as described above, reduce the drilling pressure. The then curved Shape of the free space results in a chip ejection groove.

Preferably point the main cutting edges a planned direction of rotation in the insertion position in the drilling tool radially inside a greater curvature than radially outside on. Here, the radially inwardly arranged curvature with one at least predominant Directional components vertically provided cutting direction of the insert element and radially outward point. It can be the radially outside arranged curvature with at least a predominant one Directional components in intended cutting direction of the insert element point. The course of the main cutting edge, for example, by a section of a logarithmic spiral, through an ellipsoid and / or a parabolaide. By the special curvature the free space radially inside and / or radially centered larger than formed radially on the outside be. Thereby can the chips and / or the Drill flour transported better.

It can over the longitudinal extension the main cutting breaks and / or discontinuities in the course the main cutting be provided. This measure can be part of a chip breaker device be. It can thereby produce a chip breakage at these locations become. Thus, correspondingly short and thus easily transported away Chips can be generated. This is for example at relatively large cutting edges of advantage. Prefers is, especially when using the insert element in a drill, especially in a twist drill, a steady course of the main cutting edges.

Of the Free space can counteract a planned feed direction and counter provided cutting direction of the main cutting edges extending into the Be introduced insert element. As a result, the free space or the chip ejection groove can be extended accordingly. One as a plate executed insert element can be one of the cutting side opposite have second narrow side, which here the free space with a preferably concavely curved Edge so bounded that the edge opposite the associated main cutting edge offset from the cutting direction.

The Cutting geometry can be compared to the longitudinal extent the cutting side centered a centering tip with a point angle exhibit. It is advantageously provided that the cutting edge with a cutting edge portion on both sides of the main cutting edge in the centering point extends into it. Consequently is the center point over the cutting edge areas self-tapping. This allows the dynamic pressure significantly reduced at the bottom of the hole and thus a possible cutting performance elevated become. Preferably, the provided in the feed direction rearmost point of the centering point the fulcrum of the rotational symmetry the cutting edge. In the transition from the centering point into the main cutting edge can be described above Angle change of the Lead cutting edge course, that at this point the chip breaks. Thus, this angle change Be part of the chip breaker device.

One particular advantage is seen in that the cutting edge on the entire center point runs. Thus, a correspondingly complete truncation of material in the feed direction behind the cutting edge allows, whereby the dynamic pressure can be further reduced accordingly in the bottom of the hole.

Of the Cutting edge portion can with respect to the body be formed concave of the insert element. This measure increases the actual Length of the Cutting edge section and allows a more precise one central guidance of the drilling tool.

Preferably, the centering tip to at least in one end portion of a pyramidal structure with a parallelogram as a base and four substantially triangular lateral surfaces. In this case, two of the side lines formed by the base surface and lateral surface can be arranged perpendicular to the longitudinal extension of the cutting side. Each lateral surface can form a leading edge with a laterally adjacent lateral surface of the cutting edge portion and with the other laterally adjacent lateral surface such that the cutting edge portions are formed longer than the leading edges.

The Geometry of the described pyramidal structure causes that can each form two cutting edge sections and two leading edges which, at a complete Pyramidal formation of the end portion, in the pyramid tip can converge. In the case of a concave configuration of the cutting edge section, the lateral surfaces be designed concavely corresponding to the pyramidal structure. As a result of the proposed parallelogram as a base are the cutting edge sections the same size and the Leading edges of the same size.

conditioned through the different lengths of Cutting edge sections and leading edges, the leading edges can a smaller angle than the cutting edge sections include. Thus, in Insert position in the drilling tool and / or under rotation thereof about a rotation axis equal to the pyramid height, the cutting edge portions a first conical surface and the leading edges describe a second conical surface which, relative to the Rotary axis are arranged coaxially to each other and include a gap, the equal to the free space for which is cut by the centering chips and / or Bohrmehles. Thanks to this clearance, a back pressure at the bottom of the hole can be further reduced become.

The Centering tip can over their height in the feed direction at least two consecutive sections, a rear first section in the feed direction with a first Point angle and a front in the feed direction second section having a second tip angle, and that the second tip angle greater than the first point angle is. Thus, at the transition from the first section to the second section a discontinuity in the course of the cutting edge emerge, which in turn can cause chip breaking.

Of the first point angle may be less than or equal to 40 ° or 30 ° plus / minus 15 ° and the second tip angle may be less than or equal to 80 ° or 60 ° plus / minus 30 °. Of the first tip angle may be less than or equal to 25 °, preferably less than or equal to Be 15 °, while the second tip angle may be less than or equal to 30 °, preferably be less than or equal to 10 ° can.

ever sharpener the center point is executed, the better their centering properties, but their stability is corresponding can reduce. With the division of the centering point on the one hand have a base of sufficient strength with the second section and by means of the sharper first section as a guide of the Serve drilling tool. Preferably, the height ratio of the first section with respect to the second section the feed direction in use position of the insert element in the Drilling tool about 0.5 to 1.5, preferably 1. The optimal conditions hang u. a. from the material of the material to be processed. The softer this is, the sharper the centering tip can be formed.

It it can be provided that the first section the end portion having the pyramidal structure. In a slight modification from the purely pyramidal shape, the centering tip in the feed direction converge at the ends to a wedge shape with a ridge line. This results in a ridge line, which is preferably vertical or substantially perpendicular to the longitudinal extent of the narrow side is arranged and designed as a cross-cutting edge. Preferably the center of rotation of the already described rotational symmetry is centered arranged the ridge line.

The Cutting geometry can have a Vorspanauswurfnut. The Vorspanauswurfnut can each of the one main cutting associated space or from the main cutting edge associated Spanauswurfnut in extend the free space of the centering. Here can the Vorspanauswurfnut additional Free space regarding the Forming the centering tip and / or the main cutting edge. The chip ejection groove can be allocated to the free space of the respective main cutting edge Extend cutting edge of the center point. These activities Serve for improved uptake and distribution truncated Chips and / or separated drill dust.

The Vorspanauswurfnut may extend from the space behind the respective main cutting into the free space of the centering or into the formation of a free space in the centering inside. The chip ejection groove of the respective main cutting edge can also extend into the free space of the centering tip. Preferably, the Vorspanauswurfnut extends from the Spanauswurfnut in the free space of the centering tip or in the free space of the main cutting edge associated cutting edge portion in the centering. This ensures a connection of the free spaces in the centering tip and with respect to the main cut makes, which in turn allows a slight chip removal from the main cutting edge or from the cutting edge portions and in particular from the free spaces of the centering away. This can further reduce the dynamic pressure at the bottom of the hole.

Advantageous can the cutting edge at least at one end with respect to her longitudinal extension have a cutting edge forming a side edge. This cutting edge forming the side cutting edge can immediately connect to the associated main cutting edge or, preferably against Cutting direction of the main cutting edge, spaced therefrom arranged be. In both cases can be provided that the side cutting edge with respect associated main cutting edge after cutting is effective. in the Essentially, the side cutting for lateral cutting for example, wood fibers and / or for guiding the drilling tool during the drilling process serve. The side cutting edge can with respect to their thickness in the longitudinal direction the associated main cutting against the intended cutting direction increase the same. Preferably, the increase takes place at least until in the area of the side cutting in, in which the side cutting edge is cutting active during the drilling process. This can be a corresponding size lateral support in the area largest lateral Load the side cutting edge, in which an increased lateral support is needed.

The Side cutting edge may have a curved convex course, the in use position of the insert element in the drilling tool in provided feed direction such that it is in a central region protrudes maximally in the feed direction. In this area, the Side cutting thus provided act cutting active. In this area, the reinforced one lateral support the side cutting done.

The Side cutting edge can re a planned axis of rotation of the insert element in the installed position be limited in the drilling tool from a circumferential outer circumferential surface. Hereby yourself the outer circumferential surface opposite a designated cutting direction of the main cutting edge spirally arch a small amount radially inward. This allows another, provided the drilling pressure-reducing clearance for the chips and / or the drilling dust become.

It can a drilling tool with an insert element according to a the embodiments described above be provided. the drilling tool can have a receptacle, in which the insert element is set. For this purpose, the insert element glued in the recording, soldered or welded. The drilling tool can, as already described in more detail above, be equipped with several insert elements The drilling tool can with an embodiment be provided of the insert element, in which the insert element as Insert plate with two large, parallel to each other as contact surfaces formed side surfaces and one in use position in the recording of the drilling tool in the feed direction behind, designed as a cutting side narrow side is formed. Is appropriate the recording adapted to the insert element. This can be done in the case the insert plate, the receptacle may be formed as a receiving slot. The insert element may be in contact with its contact surfaces the inner side walls rest against rotation of the receiving slot.

The Drilling tool can be designed as a drill with a drill head having an outer circumference be, in which the insert element is arranged. Preferably the insert element at both ends radially by an amount over the outer circumference projecting the drill head. This allows the bottom of the hole over his the whole area be detected by the cutting edge of the insert element.

In a further specification, the drilling tool as a twist drill formed with an elongated drill body be, whose one end formed as a drill head with the insert element is and for each major cutting edge of the insert cutting edge has a main chip ejection groove which is helical around the longitudinal axis of the drill body over at least a section of the adjoining the drill head middle part of the drill body runs. Preferably the free space of the associated main cutting edge goes into the respective one Main chip ejection groove over. This ensures that that the shavings accumulating in the various free spaces in the Hauptpanauswurfnut can be transported into it.

The The present invention will be described below with reference to several in one Drawing of illustrated embodiments explained in more detail. In show the drawing:

1 1 is a first side view of a first embodiment of an insert element designed as a plate;

2a and 2 B in each case a second side view of the first embodiment of the insert element according to FIG 1 with different angles,

3a and 3b each a plan view of the first embodiment of the insert element according to 1 , in which 3b a section IIIb according to 3a shows,

4a and 4b each a plan view of the first embodiment of the Einsatzelemen TES according to 1 with drawn circulating circle, wherein 3b a section IVb according to 3a reproduces,

5 a bottom view of the first embodiment of the insert element according to 1 .

6 a perspective view of a second embodiment of the running as a plate insert element with Vorspanauswurfnut,

7 a first side view of the second embodiment of the insert element according to 6 .

8th a plan view of the second embodiment of the insert element according to 1 .

9 a side view of a twist drill with a designed as a plate insert element and

10a C in each case a plan view of various embodiments of a drill head of a drilling tool.

In the 1 to 8th become two embodiments of an insert element according to the invention 1 reproduced in various views and detail enlargements, which serve as an insert for an in 9 shown drilling tool B is designed. In 9 is exemplified as a drill B a twist drill S with the insert element according to the invention 1 shown. 10a Figure c shows various drill heads K of a drilling tool in a plan view.

The insert element 1 is made of tungsten carbide without cutting, as it is powder metallurgically sintered from hard metal powder. According to the invention, it is a fully formed, a cutting edge 2 having cutting geometry 3 Mistake. This is produced solely by means of chipless shaping and can be cut without further post-processing, ie essentially by means of grinding, before and / or after insertion into a drilling tool. Because the cutting geometry 3 of the insert element 1 solely by sintering in one operation with the insert element 1 made by itself, the insert element 1 as in the two embodiments of the insert element 1 as an example, a much more complex and, moreover, more exact cutting geometry 3 identify as conventional insert elements. This leads, as our own experiments showed, among other things, drilling speed, drilling temperature and service life to much cheaper values than in a conventional insert element.

In the embodiments of the insert element shown here 1 is the same as an insert plate with two large, mutually parallel side surfaces 4 formed, which, as explained below with reference to 9 clarified, with their predominant extent as investment surfaces 5 for installation and torsion-resistant mounting of the insert element 1 are designed in a provided receptacle A in the drilling tool B. Furthermore, the plate-shaped insert element 1 one in use position in the receptacle A of the drilling tool B in the feed direction v behind, as a cutting side 6 trained narrow side up. In both embodiments of the insert element 1 runs the cutting edge 2 over the entire longitudinal extension l of the cutting side 6 , It is over the entire longitudinal extension l of the cutting side 6 achieved a cutting action, so that correspondingly over the entire longitudinal extent l in the not reproduced borehole material removal can take place. This avoids a build-up of pressure on the bottom of the drilling when non-removal of material is avoided.

The cutting side 6 is in use position of the insert element 1 in the drilling tool B in and perpendicular to a provided feed direction v of the drilling tool B arranged.

The cutting edge 2 has two cutting arms 7 on. These are here with respect to a geometric center in the longitudinal extent l of the cutting side 6 as a fulcrum 8th are arranged point-symmetrically. The fulcrum 8th Here is a point in the feed v backmost point of a provided centering tip 9 of the insert element 1 , As can be seen directly from the drawing, the two cutting arms 7 with respect to the fulcrum 8th opposite each other and thus include one of the sake of clarity not shown here rotation angle of 180 °, which by definition occurs at a point symmetry. The cutting arms 7 go in the pivot 8th into each other.

As shown in detail, closes in the intended cutting direction s of the cutting edge 2 at each section of the cutting edge 2 in each case a free space in their longitudinal extent 10 for receiving cut chips (not shown here) and / or separated drill dust. As a result, the back pressure and thus the drilling pressure at the bottom of the material to be processed can be further reduced.

Further, as also shown in detail, it is provided that the cutting edge 2 over its length l discontinuities 10 having. These discontinuities 10 are designed, depending on their size and / or the material to be separated, to result in breakage of a chip that is just in a discontinuous position 10 from Drilling ground is separated. The discontinuities 10 are based on abrupt angle changes or on edges that are on the cutting edge 2 run. The more serious a discontinuity 10 with respect to an undisturbed course of the cutting edge 2 is, the easier it can be a chip break.

The cutting edge 2 has in detail two main cutting edges 11 on, in the sense of the point symmetry described above, with respect to the longitudinal extent l of the cutting side 6 equidistant from the fulcrum 8th the cutting side 6 are arranged. In the cutting direction s behind each main cutting edge 11 joins the same free space 12 on, here as chip ejection 13 formed for receiving and for further transport not shown here cut chips and / or separated drill dust.

The main cutting edges 11 wise, as in particular in the 3 to 8th can be seen, with respect to their longitudinal extent l in each case a sickle-like course, wherein the curvature in the intended cutting direction s of the associated main cutting edge 11 has. Thus, the main cutting edges 11 concerning the body 14 of the insert element 1 provided with a concave curvature. As a result, in each case an enlarged clearance compared to a conventional rectilinear course of the main cutting edges 12 provided. This enlargement of the open space 12 reduces the drilling pressure.

The one main cutting edge 11 assigned free space 12 is opposite to the feed direction v and counter to the cutting direction s of the main cutting edges 11 running in the insert element 1 introduced, whereby it is extended. This is clearly the bottom view according to 5 removable, on one of the cutting side 6 opposite second narrow side 15 takes place, this as a lower contact surface 5 when using the insert element 1 is designed in the receptacle A. It is clear that they are on the lower narrow side 15 forming edge 15.1 offset against the cutting direction s to the cutting edge 2 is arranged. Thus, the free space 12 or here the Spanauswurfnut 13 to the lower narrow side 15 extended accordingly. This has the consequence that cut chips and / or separated drill dust can be transported away more easily.

Because the cutting edge 2 from the main cutting edge 11 in the center point 9 into and over the entire center point 9 runs, is the center point 9 self-tapping over its entire length, which reduces any possible dynamic pressure at the bottom of the hole. How immediate in particular 1 . 9 and 10 removable, run the main cutting edges 11 with the center point 9 an obtuse angle here and thus a discontinuity 10 in the course of the cutting edge 2 in the longitudinal extent of the same, which can cause a chip breakage as described above.

Like also in particular 1 . 9 and 10 Removable, includes the center point 9 over its entire height b ₂ in the feed direction v two successive sections on, in the feed direction v back first section 16 with a first point angle (β ₁ ) and a second section in the feed direction v 17 with a second tip angle (β ₂ ). The second apex angle (β ₂ ) is here about 64 ° significantly larger than the first tip angle (β ₁ ) with about 35 °. This will be at the point where the cutting edge 2 from the second section 17 in the first section 16 passes, again a discontinuity 10 in the course of the cutting edge 2 generated, which in turn causes a chip break as described above.

As in the plan views according to 3 . 4 and 8th As can be seen, the second section extends 17 at the level of the transition to the first section 16 over the entire width b _{3 of} the insert element 1 perpendicular thereto over a width b ₄ , which correspond approximately to a core diameter of a provided drill, in particular a twist drill. This is a core reinforcement of the plate-shaped insert element 1 achieved. The ratio of the total width b ₃ to the width b ₄ here is about 2: 1. Thus, the centering point 9 with the second section 17 a base of sufficient strength.

By the described change of the tip angle β ₁ , β ₂ is the first section 16 much sharper than the second section 17 formed, whereby an improved centering of the insert element 1 in use position in the twist drill S according to 9 is achieved. The height ratios of the relative total height b _{2 of} the centering tip 9 to the height b _{5 of} the first section 16 here is about 2: 1.

Another discontinuity 10 with a possible chip breaking at this point in the course of the cutting edge 2 adjusts itself by the chip ejection groove 13 in the second section 17 and with a small amount b ₁ in the first section 16 the centering tip 9 runs. At this point of discontinuity 10 a change of direction takes place in the course of the cutting edge 2 most clearly the top views, ie the 3 . 4 and 8th , is removable. Until this discontinuity 10 runs the cutting edge 2 from the main cutting edge 11 in the second section 17 with a directional component in the cutting direction s. Continue from this discontinuity 10 to the fulcrum 8th runs the cutting edge 2 with a directional component against cutting direction s. This is due to this discontinuity 10 a marked change of direction of the course of the cutting edge 2 before, the chip is breaking. By doing that the spa nauswurfnut 13 in the cutting direction s behind the second section 17 and extends by the amount b ₁ behind the second section, with respect to the cutting edge 2 free space in these areas 12 provided for receiving cut chips and / or separated drilling dust, which in turn counteracts a possible back pressure.

As in particular the 2 . 3 . 6 . 7 and 8th can be seen, the centering point 9 in the first end section 16 a quadrangular pyramidal structure four substantially triangular lateral surfaces 18 on. Two lateral surfaces 18 are in longitudinal extension l of the cutting side 6 and two with respect to the longitudinal extent l arranged perpendicular thereto. Every lateral surface 18 forms with a laterally adjacent lateral surface 18 a cutting edge portion 19 and with the other laterally adjacent lateral surface 18 a leading edge 20 out. Clearly visible in the plan views is that the cutting edge sections 19 longer than the leading edges 20 are formed.

Because of the different lengths of cutting edge sections 19 and leading edges 20 close the leading edges 20 a smaller angle than the cutting edge portions 19 one. Half the difference of both angles is in 2a drawn as clearance angle a ₁ . This means that there is further freedom 12 is provided for receiving cut chips and / or separated drilling dust. In 3b , a section IIIb 3a with a plan view of the center point 9 , are another clearance angle a ₂ and thus another space 12 shown from the different lengths of cutting edge sections 19 and leading edges 20 results, with both open spaces 12 spatially complementary: In use position in the drilling tool B and while rotating it about a rotation axis d equal to a marked height b ₂ , describe the cutting edge sections 19 a not shown here first conical surface and the leading edges 20 a second conical surface not shown here. As can be seen from the geometrical relationships, the conical surface areas are arranged coaxially with respect to the axis of rotation d and run at the fulcrum 8th together. Both include a gap, not shown, equal to the free space 12 for the cut by the centering chips and / or Bohrmehles.

As stated in 2a drawn radii r ₁ and r ₂ illustrates are the cutting edge sections 19 and leading edges 20 and thus the lateral surfaces 18 bent and with respect to the body 14 of the insert element 1 concave. Due to the bending of the cutting edge sections 19 an easier chip break can be initiated. Furthermore, this promotes a mechanical stability of the first section 16 , which can be designed more acute-angled and thus better centering.

Another differentiation of the cutting edge 2 takes place in the feed direction v behind end of the centering tip 9 in that the lateral surfaces, in deviation from a pure pyramidal structure in the feed direction v, form a wedge shape with a ridge line 21 converge, with the ridge line 21 perpendicular or to the longitudinal extent l of the cutting side 6 is arranged. This is the cutting edge 2 in the area of the ridge line 21 designed as a cross-cutting edge. This construction causes at both ends of the ridge line 21 a chip breakage can occur. Furthermore, this avoids a mechanically fragile pure tip. From the geometry it follows that the fulcrum 8th in the middle of the ridge line 21 is arranged.

The cutting edge 2 has at both ends with respect to their longitudinal extent in each case one side cutting edge 22 forming cutting section, by means of which, in a fibrous material to be cut to be cut radially outward cutting of the fibers can take place. Furthermore, the side cutting serve 22 the leadership of the drilling tool B in the borehole, not shown here. From the plan views according to the 3 . 4 and 8th it can be seen that the side cutting 22 in installation position with respect to the axis of rotation d circumferentially spaced and with respect to the cutting direction in front of the associated main cutting edge 11 are arranged. The 2 and 6 it is removable that the side cutters 22 extend arcuately in the feed direction v, so that they are only effective cutting in a central region. Further, they are radially inward with respect to a in 4a drawn circle of circumference 23 by means of an easily malleable and demouldable secant 24 so limited, that the side cutters 22 each have in the central region in which they are cutting action, a maximum radial width b ₅ and thus have a maximum radially inwardly acting support.

Another advantage is the 4a and in particular the 4b removable. The side cutting edge 22 is with respect to the axis of rotation d in the installation position of the insert element 1 in the drilling tool B, from a circumferential outer circumferential surface 25 limited. The outer circumferential surface 25 bulges against the cutting direction s of the main cutting edge 11 spirally radially inward by a small amount b6. As a result, another clearance angle a2 or another, the Bohrdruck degrading space 12 provided for the chips and / or the drilling dust.

In the 6 to 8th is a second embodiment of the insert element 1 shown. Yourself different from the first embodiment of the insert element 1 according to the 1 to 5 is the center point 9 on both sides a Vorspanauswurfnut 26 assigned. This extends from the Spanauswurfnut 13 that goes to the center point 9 is inserted into it, into the open space 12 formed as described above, characterized in that the cutting edge portions 19 longer than the leading edges 20 are formed. This ensures that cut chips and / or drills from the formed as a cross-cutting ridge line 21 until the transition of the centering tip 9 to the respective main cutting edge 11 into the chip ejection groove 13 transported in and thus transported away from the bottom.

As in 9 in which a twist drill S with inserted insert element 1 is shown, is the insert element 1 so set in the here slot-shaped receptacle A of the twist drill S that the Spanauswurfnut 13 immediately merges into the Hauptspanauswurfnut H of the twist drill S. This is a further transport of cut chips and / or drills from the Chipauswurfnut 13 ensured in the Hauptspanauswurfnut H of the twist drill S, so that no back pressure due to not transported further chips and / or cuttings can occur at the bottom of the hole. The insert element 1 is fixed by means of soldering and recording A. Here it lies with its lateral contact surfaces 5 laterally in the receptacle A on. It is envisaged that the insert element at about half of its total height b ₉ according to 1 is arranged in the receptacle A.

As from the first side views of the two embodiments of the insert element 1 can be seen, the plant side surface extends 5 about one in 1 drawn midline ML by an amount b ₈ addition, so that the insert element 1 with respect to a torque during rotation of the twist drill S rotationally fixed in the receptacle A. The insert element 1 is radially outwardly on both sides by an amount B ₆ from the receptacle A of the twist drill S before.

In 10 become purely schematically possible arrangements of the insert element 1 shown on a drill head K of the drilling tool B, the selection here represents a very small number of the actually possible and here, widening to the point symmetry, rotational symmetry with the previously defined fulcrum 8th prevails. In 10a points the cutting edge 2 three cutting arms 7 on, which are arranged at a rotational angle μ of 120 ° equally spaced from each other. In 10b includes the cutting edge 2 four cutting arms 7 , which are arranged at a rotational angle μ of 90 ° equally spaced from each other. Finally, in 10c eight cutting arms 7 provided, which are arranged at a rotational angle μ of 45 ° equally spaced from each other.

1

insert element

2

cutting edge

3

cutting geometry

4

side surface

5

contact surface

6

cutting side

7

cutting arms

8th

pivot point

9

centering

10

inconstancy

11

main cutting edge

12

free space

13

Spanauswurfnut

14

body

15

narrow side

15.1

edge

16

first section

17

second section

18

lateral surface

19

Cutting edge section

20

leading edge

21

First line

22

side cutting

23

peripheral circle

24

secant

25

Outer casing surface

26

Vorspanauswurfnut

A

admission

B

drilling

H

Hauptspanauswurfnut

K

wellhead

ML

center line

S

twist drill

d

axis of rotation

s

cutting direction

v

feed direction angle of rotation

β ₁

first Point angle

β ₂

second Point angle

a ₁

clearance angle

a ₂

clearance angle

a ₃

clearance angle

a ₄

clearance angle

b ₁

amount

b ₂

Height of center point

b ₃

width Insert element centering point

b ₄

width

b ₅

width

b ₆

amount

b ₇

amount

b ₈

amount

b ₉

total height

r ₁

radius

r ₂

radius

Claims (30)

Insert element for a drilling tool, in particular a twist drill, wherein the insert element ( 1 ) made of hard metal and / or ceramic, characterized in that it has a completely formed, a cutting edge ( 2 ) having cutting geometry ( 3 ), which by means of chipless shaping together with the insert element ( 1 ) is made. Insert element according to claim 1, characterized in that that it powder metallurgically from hard metal powder and / or ceramic powder is made by sintering. Insert element according to claim 1 or 2, characterized in that a cutting side ( 6 ) with the cutting edge ( 2 ) is provided and that the cutting edge ( 2 ) at least two cutting arms ( 7 ) with respect to a geometric center in the longitudinal extent (l) of the cutting side ( 6 ) as a fulcrum ( 8th ) are rotationally symmetrically arranged over a rotation angle (μ). Insert element according to claim 3, characterized that the angle of rotation (μ) 180 °. Insert element according to claim 3 or 4, characterized in that the cutting arms ( 7 ) in the fulcrum ( 8th ) merge. Insert element according to one of claims 1 to 5, characterized in that it as an insert plate with two large, mutually parallel side surfaces ( 4 ) and one in use position in a receptacle (A) of the drilling tool in the feed direction (v) rear, as a cutting side ( 6 ) formed narrow side is formed and that the cutting edge ( 2 ) over the entire longitudinal extent (l) of the cutting side ( 6 ) runs. Insert element according to one of claims 1 to 6, characterized in that in the cutting direction (s) of the cutting edge ( 2 ) at each or almost every section of the cutting edge ( 2 ) in its longitudinal extension (l) a free space ( 12 ) for receiving cut chips and / or separated drill dust adjoins. Insert element according to one of claims 1 to 6, characterized in that the cutting edge ( 2 ) over its longitudinal extension (l) discontinuities ( 10 ) and / or has interruptions. Insert element according to one of claims 3 to 8, characterized in that the cutting geometry ( 3 ) two main cutting edges ( 11 ), which with respect to the longitudinal extent (l) of the cutting side ( 6 ) equidistant from a geometric center of the cutting side ( 6 ) are arranged, and that to each main cutting edge ( 11 ) in the operating position provided in the direction of rotation or in the cutting direction (s) behind the main cutting edge ( 11 ) a free space ( 12 ) with a chip ejection groove ( 13 ) for cut chips and / or separated drill dust. Insert element according to claim 9, characterized in that the main cutting edges ( 11 ) with respect to their longitudinal extension (l) each have a sickle-like course, wherein the curvature in the cutting direction (s) of the associated main cutting edge (s) ( 11 ). Insert element according to claim 9 or 10, characterized in that the free space ( 12 ) counter to a feed direction (v) and against a cutting direction (s) of the main cutting edges ( 11 ) extending into the insert element ( 1 ) is introduced. Insert element according to one of claims 1 to 11, characterized in that the cutting geometry ( 3 ) with respect to the longitudinal extent (l) of the cutting side ( 6 ) centered a centering tip ( 9 ) with a point angle (β ₁ , β ₂ ) and that the cutting edge ( 2 ) with a cutting edge portion ( 19 ) in the centering point ( 9 ) into it. Insert element according to one of claims 1 to 12, characterized in that the cutting edge ( 2 ) over the entire center point ( 9 ) runs. Insert element according to claim 12 or 13, characterized in that the cutting edge portion ( 19 ) with respect to the body ( 14 ) of the insert element ( 1 ) is concave. Insert element according to one of claims 11 to 14, characterized in that the centering point ( 9 ) at least in one end portion of a pyramidal structure with a parallelogram as a base and four substantially triangular lateral surfaces ( 18 ), wherein two of the base surface and lateral surface ( 18 ) formed opposite side lines perpendicular to the longitudinal extent (l) of the cutting side ( 6 ) are arranged and each lateral surface ( 18 ) with a laterally adjacent lateral surface ( 18 ) the cutting edge portion ( 19 ) and with the other laterally adjacent lateral surface ( 18 ) a leading edge ( 20 ) and that the cutting edge portion ( 19 ) longer than the leading edges ( 20 ) are formed. Insert element according to one of claims 12 to 15, characterized in that the centering point ( 9 ) has over its height (b ₂ ) in the feed direction (v) at least two successive sections, a in the feed direction (v) rear first section ( 16 ) with a first tip angle (β ₁ ) and a second front in the feed direction (v) Section ( 17 ) with a second tip angle (β ₂ ) and that the second tip angle (β ₂ ) is greater than the first tip angle (β ₁ ). Insert element according to claim 16, characterized in that the first point angle (β ₁ ) is less than or equal to 40 ° and the second point angle (β ₂ ) is less than or equal to 80 °. An insert element according to claim 17, as far as dependent on claim 15, characterized in that the first section ( 16 ) has the end portion of the pyramidal structure. Insert element according to claim 18, characterized in that the centering point ( 9 ) in the feed direction (v) at the end to a wedge shape with a ridge line ( 21 ), the ridge line ( 21 ) perpendicular or substantially perpendicular to the longitudinal extent (l) of the cutting side ( 6 ) is arranged and designed as a cross-cutting edge. Insert element according to one of claims 12 to 19, as far as dependent on claim 7, characterized in that a Vorspanauswurfnut ( 26 ) is provided, each of which is a main cutting edge ( 11 ) associated free space ( 12 ) or of a main cutting edge ( 11 ) associated Spanauswurfnut ( 13 ) into the open space ( 12 ) of the centering point ( 9 ) and / or forming a free space ( 12 ) in the centering point ( 9 ) extends into it. Insert element according to one of claims 1 to 20, characterized in that the cutting edge ( 2 ) at least at one end with respect to their longitudinal extent (l) one a side cutting edge ( 22 ) has forming cutting portion. Insert element according to claim 21, characterized in that the side cutting edge ( 22 ) has a curved convex course, which in the insertion position of the insert element ( 1 ) in the drilling tool in the intended feed direction (v) bulges so that it protrudes in a central region maximum in the feed direction (v). Insert element according to claim 21 or 22, characterized in that the side cutting edge ( 22 ) with respect to a designated axis of rotation (d) of the insert element ( 1 ) in the installed position in the drilling tool (B), from a circumferential outer circumferential surface ( 25 ) is limited, wherein the outer circumferential surface ( 25 ) counter to the cutting direction (s) of the main cutting edge (s) ( 11 ) spirally bulges radially inwardly by a small amount (b ₆ ). Drilling tool with an insert element according to one of claims 1 to 23, wherein the drilling tool (B) has a receptacle (A), in which the insert element ( 1 ). Drilling tool according to claim 24, characterized in that the insert element ( 1 ) is glued, soldered or welded in the receptacle (A). Drilling tool according to claim 24 or 25, wherein the insert element ( 1 ) as an insert plate with two large, parallel to each other as contact surfaces formed side surfaces ( 4 ) and one in use position in the receptacle (A) of the drilling tool (B) in the feed direction (v) rear, as a cutting side ( 6 ) formed narrow side is formed, characterized in that the receptacle (A) is formed as a receiving slot and the insert element ( 1 ) in the presence of its contact surfaces ( 5 ) against the inner side walls of the receiving slot against rotation. Drilling tool according to one of claims 24 to 26, characterized in that it is designed as a drill with an outer periphery having drill head (K), in which the insert element ( 1 ) is arranged, wherein the insert element ( 1 ) projects radially on both ends radially by an amount (b ₇ ) over the outer circumference of the drill head (K). Drilling tool according to one of claims 24 to 27, characterized in that it is designed as a twist drill (S) with an elongated drill body, one end of which as a drill head (K) with the insert element ( 1 ) and that for each main cutting edge ( 11 ) of the cutting edge ( 2 ) of the insert element ( 1 ) has a main chip ejection groove (H) which extends helically about the axis of rotation (d) of the drill body over at least a portion of the middle part of the drill body adjoining the drill head (K), wherein the free space ( 12 ) of the associated main cutting edge ( 11 ) into the main chip ejection groove (H). Method for producing an insert element with a cutting geometry ( 3 ) for a drilling tool (B) according to one of claims 1 to 22, characterized in that the insert element ( 1 ) is powder metallurgically made of hard metal and / or ceramic powder and that in one operation, with the powder metallurgical production of the insert element ( 1 ) the cutting geometry ( 3 ) with a cutting edge ( 2 ) is incorporated so that no post-treatment for inserting the insert element ( 1 ) in the drilling tool (B) and after insertion into the drilling tool (B) is necessary. Method for the ready-to-fit assembly of a drilling tool (B), in particular into a twist drill (S), with at least one insert element ( 1 ) according to one of claims 1 to 22, wherein the drilling tool (B) has a receptacle (A) for the insert element ( 1 ), with the method steps: inserting the insert element ( 1 ) in the recording (A) and setting, in particular soldering, the insert element ( 1 ) in the picture (A)