Abstract
A tool for material-removing machining of a workpiece has a proximal and a distal end, a shaft for connecting the tool to a drive in the region of the proximal end, and a tool head in the region of the distal end. Cutting elements on the tool head are configured such that they are capable of being introduced into the workpiece to be machined and they are capable of removing a material layer from the workpiece. The cutting elements also include at least one cutting tooth having a cutting tooth ridge and a cutting tooth root, and at least one cutting jaw having a cutting jaw ridge and a cutting jaw root. The ratio between the cutting tooth ridge and the cutting tooth root is smaller, in particular between two and ten times smaller, than the ratio between the cutting jaw ridge and the cutting jaw root.
Claims
1. A tool (1) for material-removing machining of a workpiece, wherein the tool (1) has a proximal and a distal end, the tool furthermore comprising: a) a shaft (2) for connecting the tool (1) with a drive in the region of the proximal end; b) a tool head (3) in the region of the distal end; c) cutting elements (4, 4.1, . . . , 4.5, 5, 5.1, . . . , 5.3) on the tool head (3), wherein the cutting elements (4, 4.1, . . . , 4.5, 5, 5.1, . . . , 5.3) are structured in such a manner that they are able to penetrate into the workpiece to be machined and able to remove a material layer from the said workpiece, and wherein d) the cutting elements (4, 4.1, . . . , 4.5, 5, 5.1, . . . , 5.3) furthermore comprise at least one cutting tooth (4, 4.1, . . . , 4.5) having a cutting tooth ridge (D.sub.6, D.sub.6.1, . . . D.sub.6.5) and a cutting tooth root (D.sub.7, D.sub.7.1, . . . D.sub.7.5) and at least one cutting jaw (5, 5.1, . . . , 5.5) having a cutting jaw ridge (D.sub.8, D.sub.8.1, . . . D.sub.8.5) and a cutting jaw root (D.sub.9, D.sub.9.1, . . . D.sub.9.5), and wherein the ratio between cutting tooth ridge (D.sub.6, D.sub.6.1, . . . D.sub.6.5) and cutting tooth root (D.sub.7, D.sub.7.1, . . . D.sub.7.5) is smaller than the ratio between cutting jaw ridge (D.sub.8, D.sub.8.1, . . . D.sub.8.5) and cutting jaw root (D.sub.9, D.sub.9.1, . . . D.sub.9.5), in particular 2 to 10 times smaller.
2. The tool (1) according to claim 1, wherein the ratio between cutting tooth ridge (6, 6.1, . . . 6.5) and cutting tooth root (7, 7.1, . . . , 7.5) lies in a range of between 1 to 2 and 1 to 25, preferably of between 1 to 5 and 1 to 20, further preferably of between 1 to 10 and 1 to 15.
3. The tool (1) according to claim 1, wherein the ratio between cutting jaw ridge and cutting jaw root lies in a range of between 1 to 1 and 1 to 1.9, preferably of between 1 to 1.1 and 1 to 1.75, particularly preferably of between 1 to 1.3 and 1 to 1.5.
4. The tool (1) according to claim 1, wherein the at least one cutting tooth ridge is structured in such a manner that it defines a first machining radius during a rotation of the tool about its longitudinal axis, and wherein the at least one cutting jaw ridge (D.sub.8, D.sub.8.1, . . . D.sub.8.5) is structured in such a manner that it defines a second machining radius during a rotation of the tool about its longitudinal axis, and, in particular, wherein the first machining radius is greater than the second machining radius.
5. The tool (1) according to claim 1, wherein the cutting jaws are structured in such a manner that the cutting jaw ridges project beyond the cutting tooth root rotation circumferences in terms of their cutting jaw rotation circumference by the longitudinal axis (L), so that a first edge formed by the cutting tooth roots is removed from the workpiece by the width of the cutting jaws, in particular that in this way, an excess (28) is removed.
6. The tool (1) according to claim 1, wherein the at least one cutting tooth has a face edge (10) and a rear edge (11).
7. The tool (1) according to claim 1, wherein the tool comprises a plurality of cooling channels, which extend through the shaft parallel to the longitudinal axis (L) of the tool.
8. The tool (1) according to claim 7, wherein the shaft (2) narrows toward the tool head (3), so that a shoulder (2.1) is formed, and the cooling channels (20) have cooling openings (14, 14.1, 14.2) on this shoulder (2.1), and, in particular, wherein the cooling openings (14, 14.1, 14.2) extend radially around a longitudinal axis (L) of the tool on this shoulder (2.1), in particular wherein the cooling openings (14, 14.1, 14.2) have an essentially half-moon shape.
9. The tool (1) according to claim 1, comprising coolant openings (14, 14.1, 14.2), which are disposed on the tool (1) axially relative to the longitudinal axis and coaxial with a cutting gap (13, 13.1, 13.2).
10. The tool (1) according to claim 1, comprising a plurality of cutting teeth (4. 4.1, 4.2), and wherein at least a first cutting tooth (4) is disposed relative to a second cutting tooth (4.1, 4.2) in such a manner that the first and the second cutting tooth have an overlapping but not congruent rotation circumference (30, 30′, 30″) about the longitudinal axis (L).
11. The tool (1) according to claim 1, comprising a plurality of cutting jaws, and wherein at least a first cutting jaw is disposed relative to a second cutting jaw (5.1, 5.2), in such a manner that the first and the second cutting jaw have an overlapping rotation circumference with at least one cutting tooth.
12. The tool (1) according to claim 1, wherein the tool is coated with an abrasion-resistant layer, in particular the tool head is coated with an abrasion-resistant layer.
13. A method for the production of a shaped part by means of material-removing machining of a workpiece using the tool (1) according to claim 1, comprising the steps: a) contacting the tool with the workpiece to be machined, so that cutting elements of the tool penetrate into the workpiece to be machined, and wherein b) at least one cutting element structured as a cutting tooth removes a first recess (30, 30′, 30″), which essentially corresponds to the shape of the cutting teeth, and c) at least one cutting element configured as cutting jaws removes a second recess (28, 28′, 28″), and characterized in that the at least one cutting jaw is structured in such a manner that it is able to widen the wedge foot created by the cutting tooth, which is essentially wedge-shaped in terms of its profile side, at its widest location.
14. The method according to claim 13, wherein cutting teeth and cutting jaws successively remove the material, so that first recess edges created by a first machining cutting element are further removed by a successive machining step, by means of another cutting element.
15. The method according to claim 13, wherein a first cutting tooth removes a first recess from a workpiece, and wherein a second cutting tooth removes a second recess from the workpiece, which recess overlaps with the first recess, and a first cutting jaw removes a third recess from the workpiece, which overlaps with the first and/or the second recess.
16. A shaped part that can be obtained by means of the method according to claim 13, wherein the shaped part has at least one helical profile notch.
Description
[0069] In the following, the present invention will now be explained further using concrete exemplary embodiments and drawings, without being restricted to these. To a person skilled in the art, further advantageous embodiments, which are embodiments of the solution according to the invention, are evident from these examples.
[0070] The figures schematically show:
[0071] FIG. 1a a tool according to the invention;
[0072] FIG. 1b the tool head from FIG. 1a, enlarged;
[0073] FIG. 1c the tool head from FIG. 1b, in perspective;
[0074] FIG. 1d a cross-section through the section plane Y-Y from FIG. 1b;
[0075] FIG. 1e a tool according to the invention in a frontal view; FIG. if a first cutting element of FIG. 1a;
[0076] FIG. 1g a second cutting element of the embodiment from FIG. 1a;
[0077] FIG. 1h a cutting jaw from the embodiment of FIG. 1a;
[0078] FIG. 1i schematically, the cutting edge that can be achieved with the tool according to FIG. 1a;
[0079] FIG. 2a an alternative embodiment of the tool according to the invention;
[0080] FIG. 2b the tool head of the embodiment of FIG. 2a;
[0081] FIG. 2c different section planes through the tool head of FIG. 2a;
[0082] FIG. 2d a cross-section through the section plane Y-Y of FIG. 2b;
[0083] FIG. 2f schematically, the cutting elements of the embodiment of FIG. 2a in relation to a perpendicular line S to the longitudinal axis;
[0084] FIG. 2g schematically, the overlaps of the cutting elements of FIG. 2a;
[0085] FIG. 2h schematically, the tool head of FIG. 2a in a perspective view;
[0086] FIG. 2i longitudinal cross-section through the tool from FIG. 2a;
[0087] FIG. 3a a further alternative embodiment of a tool according to the invention;
[0088] FIG. 3b the tool head of the embodiment shown in FIG. 3a;
[0089] FIG. 3c perspective view of the tool head;
[0090] FIG. 3d schematically, the cutting elements of the embodiment of FIG. 3a in relation to a number of perpendicular lines relative to the longitudinal axis;
[0091] FIG. 3e schematically, an overlap of the cutting elements of the tool of FIG. 3a.
[0092] Unless explicitly mentioned otherwise, the analogous elements are represented with the same reference symbol in different figures, in each instance.
[0093] FIG. 1a shows a tool 1 according to the present invention, as an example. The tool can be roughly divided into two regions 2, 3, a shaft 2 and a tool head 3. The distal end is situated in the region of the tool head 3 and is formed by the farthest point in the longitudinal direction, while the proximal end is situated on the precisely opposite side on the shaft 2. In FIG. 1a, a longitudinal axis L is also shown, which runs through the center point of the circumference cross-section of the shaft 2 and, at the same time, forms the axis of rotation of the tool 1 during operation. The tool 1 shown in FIG. 1a can be used, for example, in order to mill a profile groove in a pre-drilled opening, or to mill an outside thread on a pin, in that the tool 1 is rotated about its longitudinal axis L and is guided translationally along a cylinder mantle of the said bore or the said pin by a drive, in a helical movement. The material-removing machining takes place at the tool head 3, and in the representation of FIG. 1a as shown, two cutting elements 4, 4.1, both of which are cutting teeth 4, 4.1, can be seen in the case of the tool head that is triangular in cross-section, overall. The tool 1 also possesses a cutting jaw, but in the representation shown, this cannot be seen. In the present example, the tool is structured in multiple parts. The tool head 3 is in one piece and consists of a particularly hard material, which is selected by a person skilled in the art in such a manner that it is at least harder than the material of the workpiece that is to be machined. The shaft 2 can be produced from a comparatively less expensive or lighter material. In the present example, the tool head 3 was connected with the shaft 2 by way of a shoulder 2.1. The shoulder 2.1 represents a narrowing of the shaft 2 toward the tool head 3. In the present example, the tool head 3 was locked into the shaft 2 by way of a bayonet closure. Fundamentally, however, all types of a shape-fit or force-fit connection are conceivable in the case of such a two-part tool 1. It is also possible to produce the entire tool 1 shown as a single-piece tool. A single-piece tool would have the advantage of increased stability. In the case of a two-part or multi-part tool 1, maintenance is easier and production of the cooling channels (not shown in FIG. 1a) is simpler. The exemplary tool 1 is made of steel and has a total length G of between 50 and 60 mm. Of course, the dimensions of the tool 1 are primarily determined by the intended machining. The values indicated are purely examples and can vary. The ranges do not represent any imprecision, but rather give a good basis for the exemplary tool, so as to be able to produce specific standardized threads. In a particularly concrete embodiment of the tool 1, the tool has a total length of 55 mm and a diameter of 4 mm (shaft diameter).
[0094] In FIG. 1a, two cooling openings can also be seen, which open out of the shoulder 2.1 and are disposed radially about the longitudinal axis L. The cooling openings 14, 14.1 open into cooling passages (not shown), which run parallel to the longitudinal axis L. During operation, a jet of coolant is sprayed to the tool head, parallel to the longitudinal axis, by means of the cooling openings 14, 14.1. Due to the rotation of the tool 1 about the longitudinal axis L, a radial coolant curtain is thereby formed, which optimally cools the material-removing process.
[0095] FIG. 1b shows an enlarged representation of the tool head 3 of the tool 1 from FIG. 1a. The tool head 3 begins with the end of the narrowing of the shaft in the form of a shoulder 2.1, forming a tool neck 3.1. The progression of the longitudinal axis L through the tool head 3 can also be seen. At the distal end of the tool head 3, there is a distal head surface 12. The cutting elements 4, 4.1 extend in wedge shape away from the tool head. Between the cutting elements 4, 4.1, there is a cutting gap 13, which simplifies material removal. In the present example, the wedge-shaped cutting teeth 4, 4.1 penetrate into the surface of the workpiece and peel a wedge-shaped groove out of it, wherein the chips are discharged by way of the cutting gap 13. In the present example, the tool neck 3.1 approximately corresponds to the depth of the thread to be produced. In the case of the upper cutting tooth 4 (based from the orientation in the figure), a face edge 10 and a rear edge 11 of the cutting tooth 4 can also be seen. The analogous second cutting tooth 4.1, which is offset from the first cutting tooth 4 by 120° in the clockwise direction, also has a face edge 10.1 and a corresponding rear edge 11.1. In the present exemplary tool, the placement of the cutting teeth 4, 4.1 is on the same plane perpendicular to the longitudinal axis. Likewise, the cutting teeth 4, 4.1 are of equal size. This means that the groove milled out by the cutting teeth 4, 4.1 during stationary rotation of the tool is congruent.
[0096] In this example, the cooling opening 14 is disposed essentially coaxially with the cutting gap 13.
[0097] Proceeding from the exemplary values of FIG. 1a, the tool head 3 is between 10-12 mm long. Tool heads having a length of 0.6 to 25 mm are usual for thread sizes in the size M0.3-M6, wherein the final configuration can be determined by a person skilled in the art using the machine requirements and the thread size to be produced.
[0098] FIG. 1c shows the tool head 3 from FIG. 1b in a perspective, frontal view from the distal end. In this perspective, the placement of the cutting elements 4, 4.1 and 5 is particularly clearly evident, proceeding from the distal end surface 12. The cutting elements 4, 4.1, 5 are disposed in a circular arrangement about the center point of the tool, spaced apart from one another by 120°. The perspective shown shows the cutting jaw 5 and two opposite cutting teeth 4, 4.1; the cutting gap 13.2 is situated between the cutting jaw 5 and the first cutting tooth 4. The cutting elements 4, 4.1, 5 are connected with the narrowing distal shaft end 2.1 by way of a tool head neck 3.1. Likewise, from this perspective view the coolant opening 14.2, which opens laterally on the narrowing distal shaft end 2.1, can be seen well. It is disposed in the same longitudinal plane as the cutting tooth gap 13.2, and during operation, this can lead to better distribution of the coolant. Analogously, a further cooling opening 14.1 is disposed coaxial with a further cutting gap 13.2. Although the cooling openings 13.1, 13.2 open laterally on the shoulder 2.1, the mouth leads to an axial coolant feed during operation.
[0099] FIG. 1d schematically shows the cross-section through the cutting elements of the tool head 3 from FIG. 1b in the section plane Y-Y. From this figure, the radial placement of the cutting elements 4, 4.1, 5 about the center point (the longitudinal axis L) and the resulting, essentially triskelion arrangement of the three cutting elements 4.1, 4.2, and 5 is particularly evident. The center points of the cutting elements are spaced apart from one another by about 120°.
[0100] FIG. 1e analogously shows a frontal view of the tool head and various section planes Z1-Z1, Z2-Z2, and Z3-Z3, which explain the individual cutting elements 4, 4.1, 5 of the tool of FIG. 1a in greater detail.
[0101] In the frontal view of FIG. 1e, the distal end of the tool head is formed by the distal head surface 12. Proceeding from this surface, three cutting elements 4, 4.1, 5 extend in the distal direction, two of which are configured as cutting teeth 4, 4.1 and one of which is configured as a cutting jaw 5. Three cooling openings 14, 14.1, 14.2 are disposed on the shoulder 2.1, radially around the center point L, which is situated on the longitudinal axis L. These are spaced apart from one another by an angle W.sub.Z of 120 degrees. The cutting elements 4, 4.1, 5 extend outward from the tool head in the center of these angles, in other words spaced apart from one another by 120, in each instance, respectively spaced apart from the cooling openings by 60 degrees, so that an essentially triskelion shape of the tool head exists in a frontal view.
[0102] In Figure if, the section plane Z1-Z1 through a cutting tooth 4 is shown. The cutting tooth has an essentially wedge-shaped shape. In this regard, the wedge is formed by two flanks, a face flank 10 and rear flank 11, and ends in a round tip. The cutting tooth ridge is dimensioned as the distance of the two end points of the flanks 10, 11. This means that the ridge is dimensioned as the distance, in this example, where the face flank 10 and the rear flank 11 make a transition into the radius of the round tip. This cutting tooth ridge has a length D.sub.6. The face flank 10 extends from the distal end of the tool head toward the cutting tooth ridge, at a specific angle W.sub.10. In the present example, the angle W.sub.10 is an angle of 60°. The edges that are formed when the cone impact form the points that are decisive for dimensioning the width of the cutting tooth root D.sub.7. In the present example, the face edge 10 starts to extend upward from approximately 0.4 mm from the distal surface 12, at an angle W.sub.10 of 60° to a parallel line of the longitudinal axis, and ends in a cutting tooth ridge having a width D.sub.6 of 0.05 mm. The cutting tooth root D.sub.7, which runs parallel to the cutting tooth ridge D6 in this example, has a width of 0.6 mm. In this concrete example, this cutting tooth 4 has a ratio between cutting tooth ridge and cutting tooth root of 1 to 12.
[0103] Analogously to this, the second cutting tooth 4.1 is shown in the section plane Z2-Z2 in FIG. 1g. This cutting tooth has the same dimensions as the cutting tooth 4 from FIG. 1f. The two cutting teeth are therefore essentially congruent. The distance D.sub.19.1 from the distal end to the face-side cutting tooth root is the same as the analogous distance D.sub.19 of FIG. 1f, in other words approximately 0.4 mm from the distal end surface 12.
[0104] In FIG. 1h, the cutting jaw 5 of the corresponding tool 1 is shown in the section plane Z3-Z3. The cutting jaw 5 is also formed by a face edge 16 and a rear edge 17, which enclose an angle W.sub.w16 of 10° relative to a parallel line to the longitudinal axis. The edges 16, 17 form a cutting jaw ridge between them, having a width D.sub.8. The starting edges of the edges 16, 17 form the cutting jaw root, having a cutting jaw root width D.sub.9, by means of their distance. In the present example, the width of the cutting jaw root D.sub.9 is 1.4 mm. The width of the cutting jaw ridge D.sub.8 is 1.05 mm. The ratio between cutting jaw ridge and cutting jaw root amounts to approximately 1.3 (1.33 periodically) in the present example 1.
[0105] Therefore the ratio in the case of the cutting teeth 4, 4.1 is approximately ten times smaller, in comparison with the cutting jaws 5 in the embodiment of the example from FIG. 1a, in the case of the cutting teeth than in the case of the cutting jaws (1 to 12 vs. 1 to 1.3).
[0106] FIG. 1i shows a groove (bold solid line) milled out of the tool from FIG. 1a, in static rotation about the longitudinal axis, as an example. The machining tools 4, 4.1, and 5 successively penetrate into the material, and thereby (schematically) form a thread notch 35 with the surface 5′, 4′, 4′, 4.1′.
[0107] In this regard, in a first machining step, a groove having a first surface 4″/4.1″, 4′/′4.1′ is cut out by the cutting teeth, which rotate congruently. In a second machining step, an excess 28 is cut off from an edge of the groove by the cutting jaw. As a result, the thread groove 35 is widened and a clean cut edge is formed on the thread groove, with a new surface 5′.
[0108] An alternative embodiment of a tool 1 according to the invention is shown in FIG. 2a. This tool, too, is a tool 1 that extends in a longitudinal direction L, composed of a shaft 2 and a tool head 3. The shaft 2 narrows toward the tool head 3, in a shoulder 2.1, and has openings 14 for the feed of coolant during the machining process on this shoulder 2.1. The tool head ends, at its distal end, in a number of cutting elements 4, 4.1, 5 (the cutting jaw, No. 5, cannot be seen in this perspective). CH 706 934 (Mikron Tool SA Agno, CH) describes the arrangement of cooling channels on a milling tool, in which an exit opening of a fluid channel is disposed precisely below a shaft shoulder.
[0109] FIG. 2b correspondingly shows the tool head 3 in an enlarged representation, wherein the shaft 2 makes a transition into the shoulder 2.1, on which the cooling openings 14. 14.1 are situated. By way of a tool neck 3.1, the tool head 3 ends with a distal end surface 12 and the cutting elements 4, 4.1 at its distal end, wherein a first cutting element 4 has a face edge 10 and a rear edge 11. The section plane Y-Y will be explained in greater detail below, in FIG. 2d. This tool, too, has an essentially triskelion basic shape and a machining radius, wherein the cutting elements are disposed on the longitudinal axis around a centers point, spaced apart from one another at an angle of approximately 120° in the clockwise direction. The first cutting tooth 4 is followed by a cutting tooth gap 13 and a second cutting tooth 4.1, once again followed by a cutting tooth gap 13.1, and the cutting jaw 5, followed by a further cutting tooth gap 13.2.
[0110] A top view of this is shown in FIG. 2c, which also shows an essentially triangular arrangement of the cooling openings 14, 14.1, and 14.2 at the shaft narrowing 2.1. In FIG. 2c, the corresponding section planes through the cutting elements, Z1-Z1, Z2-Z2, and Z3-Z3 are also shown, which an offset [the noun Versatz=offset is used for the first time here; later in the document the noun Offset (obviously based on English) is also used; only one translation (offset) is possible for both] of the cutting elements is supposed to illustrate in greater detail, in connection with FIG. 2f.
[0111] FIG. 2d shows the aforementioned section plane Y-Y from FIG. 2b. The essentially triskelion arrangement of the cutting elements 4, 4.1, 5 and the cutting gaps 13, 13.1, 13.2 disposed between the cutting elements 4, 4.1, 5 are clearly evident.
[0112] For a better representation of the offset arrangement of the cutting elements 4, 4.1, 5 in contrast to the embodiment of FIG. 1a, in FIG. 2f the cutting elements are shown in relation to a perpendicular line S to the longitudinal axis and in relation to one another. For illustration purposes, the cutting teeth 4, 4.1, in particular, are shown one on top of the other. The perpendicular line S was selected in such a manner that it runs through the center point of the width of the cutting jaw 5.
[0113] The offsetting of the distal root base of the cutting elements 4, 4.1, 5 in relation to the perpendicular line S is shown as the offset D.sub.4, D.sub.4.1 in FIG. 2f. In this regard, the first offset D.sub.4 of the cutting tooth 4 is smaller than the second offset D.sub.4.1 of the second cutting tooth 4.1. During operation, this has the result that a thread groove having a first width is cut out by the first cutting tooth, while the thread groove is widened by the second cutting tooth and a second width is formed. In other words, only the shape of the face edge 10 and a corresponding cutting tooth ridge section of the resulting groove are determined by the first cutting tooth 4, while the shape of the rear edge 11.1 and the corresponding cutting tooth ridge section are determined by the second cutting tooth 4.1.
[0114] Alternatively or supplementally, widening of the thread groove can also by way of displacement of the tool, so that successive machining of the workpiece with a first and a second cutting tooth leads to widening of the said groove.
[0115] The cutting teeth are formed by their corresponding side edges 10, 11, 10.1, 11.1, which spread away from a parallel line to the longitudinal axis at angles W.sub.10, W.sub.10.1. The angles W10 and W10.1 are shown at 60° in this example. The ultimate shape of the cutting tooth and thereby the angles of the cutting tooth edges are, of course, dependent on the thread shape to be achieved, and can be adapted within the scope of the present invention by a person skilled in the art. In this embodiment, the cutting tooth ridge runs parallel to the longitudinal axis, as a straight line.
[0116] The first cutting tooth 4 has a ratio between cutting tooth ridge D.sub.6 and cutting tooth root D.sub.7 of 1 to 19. It has an offset D.sub.4 from the perpendicular line that is smaller than a second offset D.sub.4.1 of the second cutting tooth 4.1 from the perpendicular line S. The second cutting tooth has a ratio between cutting tooth ridge D.sub.6.1 to cutting tooth root D.sub.7.1 of 1 to 19.
[0117] In the case of the cutting jaw 5, the perpendicular line S runs through the center of the width of the cutting tooth jaw D.sub.9 and of the corresponding cutting jaw ridge D.sub.8. A cutting jaw offset D.sub.5 corresponds to half the distance D.sub.8, respectively Dg. The ratio between cutting jaw ridge D.sub.8 and cutting jaw root D.sub.9 amounts to approximately 1 to 1.35. As in the preceding example, these ratios and dimensions are merely indicated as examples, and the real dimensions of a concrete embodiment can be determined and selected by a person skilled in the art based on the situation, based on the desired thread size.
[0118] The cutting jaw 5 possesses a face edge 16 and a rear edge 17, which ends in a notch 21, which extends into the tool neck (not shown).
[0119] The sequence of this arrangement is illustrated using a schematic groove in FIG. 2g. The first cutting tooth 4 having the offset in the proximal direction with regard to the perpendicular line S forms the edge 4′. Offsetting of the cutting teeth 4, 4.1 relative to one another leads to the result that the entire recess 35 of the groove is formed by the overlap of the two cutting teeth and additionally the offsets 37, 37′ on both sides. Thus, a first offset 37 is formed by the face edge of the second cutting tooth, and second offset 37′ is formed by the rear edge of the first cutting tooth.
[0120] In order to obtain a groove as shown in FIG. 2g, the cutting teeth are therefore structured, in total, in such a manner that they are narrower than the groove. Because of the offset of the cutting teeth with regard to the perpendicular line, an additional offset is removed and the cutting teeth describe different rotation circumferences. The face-side groove flank is formed by the second cutting tooth 4.1, while the proximal groove flank 4′ is formed by the first cutting tooth.
[0121] The groove is further widened at its side edges by the cutting jaw(s), in that these remove the excess 28.
[0122] The machining described takes place successively during the rotation of the tool. In use, however, this is more complex, since in general, the tool is helically moved in the thread direction when producing a thread. By means of the tool according to the invention, to cut and de-burr using a single work step. The resulting profiles are particularly precise and essentially free of burrs.
[0123] The description of the work sequence and the numbering of the individual cutting elements takes place for a better illustration in this application. In operation, however, the sequence of the machining plays no role and it is very complicated to control it, in any case, since the tool is rotating rapidly.
[0124] Analogous to the embodiment of FIG. 1, in this example, too, an excess 28 is cut off by the cutting jaw, so that widening of the groove takes place, with simultaneous de-burring of the cut edge that is produced by the cutting teeth. This process, too, can take place successively.
[0125] FIG. 2h schematically shows a tool head from the embodiment of FIG. 2a in a perspective view, wherein the three cutting elements 4, 4.1, and 5 can be particularly well seen in their triskelion arrangement. The cutting tooth 4 and the cutting jaw 5 enclose a cutting tooth gap 13.2 in the radius, which gap lies on the same plane as an essentially half-moon-shaped cooling opening 14.2 in the longitudinal direction. As a result, in the process coolant can optimally reach the machining location, and chip discharge can take place more easily. Likewise, the further cooling openings 14, 14.1 arranged with the corresponding cutting tooth gaps are also disposed on the shoulder 2.1 of the shaft 2. In the clockwise direction, the cutting elements 5, 4, 4.1, the cutting jaw 5, the cutting tooth 4 with its face edge 10, and the cutting tooth 4.1 with its face edge 10.1 can be seen.
[0126] For machining of particularly hard materials, the tool head or at least the cutting elements can be provided with a particularly abrasion-resistant coating. In the concrete example, the cutting tooth head consists of hard metal and was provided with a titanium nitride layer. This ceramic coating is particularly hard and corrosion-resistant and resistant to wear.
[0127] Using the solution according to the invention, it is also possible to produce complex threads having different thread sizes that run parallel.
[0128] FIG. 2i shows the placement of the cooling channels 20 in a longitudinal cross-section through the tool from FIG. 2a, using a concrete example. The cooling channel 20 extends from the proximal end of the tool 1 to the narrowing of the shaft, and there opens laterally into a coolant opening 14.
[0129] A particular, further alternative embodiment is shown in FIG. 3a, where a tool 1 is shown having a shaft 2 that extends in the longitudinal direction L and ends in a tool head 3, and is connected with the latter by way of a shoulder 2.1. In this embodiment, too, lateral coolant openings 14 are disposed on the shoulder 2.1. The tool head ends in a number of cutting teeth 4, 4.1, 4.2, and furthermore cutting elements that cannot be seen from this perspective.
[0130] Although the tools shown as examples all follow an essentially triskelion arrangement, quadragonal, pentagonal or hexagonal cross-sections are also certainly conceivable.
[0131] FIG. 3b shows the tool head once again, on a larger scale, where the individual cutting elements 4, 4.1, and 4.2 can be seen particularly well in their relationship to one another. Two first cutting teeth 4, 4.1 are situated on a first machining axis parallel to the longitudinal axis, while a third cutting tooth 14.2 is disposed on a second machining axis parallel to the longitudinal axis. The tool head 3 makes a transition into a shoulder 2.1 in the longitudinal direction L, from its proximal end, on which shoulder coolant openings 14 are disposed. At its distal end, it first has a first cutting element 4, having a first face edge 10 and a first rear edge 11. At a distance 33, a second cutting edge 4.1 having a second face edge 10.1 and a second rear edge 11.1 now follows in the same longitudinal plane.
[0132] A third cutting tooth 4.2 is disposed at a distance of a tooth gap 13, which tooth has a distance from the distal end surface of the tool head 3 that is greater than that of the first cutting tooth 4. In this embodiment, this third cutting tooth 4.2 would come to lie precisely in the gap between the first cutting tooth 4 and the second cutting tooth 4.1. This third cutting tooth also has a face edge 10.2 and a rear edge 11.2.
[0133] FIG. 3c shows the tool head of FIG. 3a in a perspective view.
[0134] The essentially triskelion arrangement of the cutting elements 4, 4.2, and 5 can also be seen. It can also be seen that the cutting elements 4, 4.1 are disposed offset from one another in terms of their axis. The cooling openings 14, 14.1, and 14.2 are disposed on the shoulder 2.1 at a distance of 120°.
[0135] In FIG. 3d, the cutting elements 4, 4.1, 4.2, 5, 5.1, and 5.2 are shown schematically in relation to one another and with reference to three perpendicular lines R.sub.1, R.sub.2 and R.sub.3. The perpendicular lines R1, R2, and R3 represent perpendicular planes relative to the longitudinal axis of the tool.
[0136] From the distal end, the first cutting element is a first cutting jaw 5, which is formed by a face edge 16 and a rear edge 17. Next, a first cutting tooth 4 follows, running through the center point of the first rotation radius, having a face edge 10 and a rear edge 11. The first cutting tooth has a cutting tooth ridge D.sub.6 and a cutting tooth root D.sub.7. The ratio of the width between the cutting tooth ridge D.sub.6 and the cutting tooth root D.sub.7 amounts to 1:13 in this case. The next cutting element is a second cutting jaw 5.1, which is disposed between the two perpendicular lines R1 and R2 and formed by a face edge 16.1 and a rear edge 17.1. The fourth cutting element is a second cutting tooth 4.2, which has a lesser volume than the first cutting tooth 4. This cutting tooth also has a face edge 10.2 and a rear edge 11.2. This cutting tooth also has a width of the cutting tooth wheel D.sub.6.2 and a width of the cutting tooth root D.sub.7.2. In this case, the ratio is 1:9.25.
[0137] A third cutting jaw 5.2 follows, having a face edge 16.2. This cutting jaw possesses no rear edge, but rather ends directly in a notch 21 following the tool neck (not shown). A last, third cutting tooth 4.1, which has a smaller volume than the cutting tooth 4.2, concludes the cutting elements and has a face edge 10.1 and a rear edge 11.2. The ratio between the width of the cutting tooth ridge D.sub.6.1 and the width of the cutting tooth root D.sub.7.1 amounts to 1:5.33 in this case.
[0138] It is shown schematically in FIG. 3e how a tool head arranged in this manner is able to machine a workpiece. The cutting teeth engage into the workpiece in such a manner that the recesses of the thread groove 30, 30′, 30″ are formed. The excesses 28, 28′, 28″ at the edges of the thread grooves are further removed by subsequent machining of the cut edges by the cutting jaws. De-burred, highly precise, and clean threads are produced.
[0139] In this regard, the cutting jaws are always arranged in such a manner that they a successive machining step after engagement of the cutting teeth, an excess that remains at the edges formed by the cutting teeth is removed. Also, the cutting teeth are arranged in such a manner that they together can form a single, continuous thread groove, which extends in spiral shape along a workpiece, during successive machining, either by means of an offset relative to a perpendicular line relative to the longitudinal axis of the tool, or by means of different cutting tooth geometries, in other words variation of the cutting tooth ridge width and cutting tooth root width. This can be achieved by way of the geometry of the tool, as described here, in combination with control of the tool, as is already known.
[0140] The concrete embodiments shown in this application are intended to show possibilities within the inventive concept as examples, and to illustrate the invention. Of course, individual characteristics from the individual embodiments can be combined with one another as desired, if they thereby form a practical tool for material-removing machining of a workpiece. Even alternatives that are not shown, having quadragonal, pentagonal or even hexagonal profile cross-sections, as well as curves, are conceivable.
