Pull-out protection of tools from tool holders with a tool receptacle

Abstract

System comprising tool holder (1) and rotary tool (2), wherein the tool holder has a chuck with a cylindrical tool receptacle (7) and the cylindrical shank (11) of the rotary tool (2) is received therein, wherein the system has a pull-out protection device that prevents axial migration of the rotary tool due to vibration, which comprises at least one locking element (4, 19) and at least one corresponding locking groove (12, 13) that receives the locking element, wherein the locking groove is arranged in the circumferential surface of the shank of the rotary tool starting from the end face and the locking element is arranged in the chuck, the rotary tool is torque-resistant by the chuck with a press fit during operation and is held axially with respect to the axis of rotation (3) by the pull-out protection device, wherein the locking groove (12, 13) has a locking groove profile which is helical,is curved or formed from compound, partially straight and curved cylindrical surface paths, wherein it extends at least over a partial section of the shaft (11), such that the locking groove and locking element interact in a positive-locking manner, characterized in that the rotary tool has at least two, particularly preferably four, locking grooves, and wherein the chuck is a shrink-fit chuck.

Description

[0001] The present invention relates to a system comprising a tool holder and a rotary tool according to the preamble of claim 1.

[0002] Tool holders with chucks, especially shrink-fit chucks, are widely known. They are used to clamp pipe, turning, milling, reaming, and grinding tools, or similar items, via a thermally induced shrink-fit process. Typically, such shrink-fit chucks are thermally heated by an inductive shrink-fit system, which increases the inner diameter of the chuck. With the increased inner diameter, the tool to be clamped is inserted into the shrink-fit chuck. The ratio of the chuck's inner diameter to the tool's shank diameter is designed such that, upon subsequent cooling of the shrink-fit chuck, the tool is clamped securely to the chuck, preventing torque.

[0003] From WO 01 / 89758 A1, it is known to heat the sleeve section inductively by means of an annular coil arrangement that surrounds the sleeve section substantially coaxially. The coil arrangement is connected to a high-frequency AC generator and induces eddy currents in the metallic sleeve section, which heat the sleeve section. To prevent stray fluxes and to concentrate the magnetic flux, magnetic flux concentrator elements made of soft magnetic, essentially non-conductive material, such as ferrite or the like, are arranged on the end faces and the outer circumference of the coil arrangement. These elements direct the magnetic flux generated by the coil arrangement onto the sleeve section of the tool holder and, in particular, into the region of the free end of the sleeve section.

[0004] The problem with toolholders featuring chucks for rotary tools with a cylindrical shank is the axial migration of the rotary tool along the chuck's axis of rotation during operation. This axial migration is caused by vibrations that occur while machining the workpiece. Due to this adverse effect, workpieces can no longer be machined precisely and with dimensional accuracy. Furthermore, tilting of the rotary tool in the workpiece or even in the chuck holding the workpiece could lead to dangerous accidents. Under unfavorable conditions, the rotary tool could even, in extreme cases, leave the toolholder's chuck during operation, thus posing a significant hazard to the machine operator.

[0005] A tool assembly with a pull-out protection device is known from DE 42 22 809 A1.

[0006] DE 199 63 657 A1 shows a clamping mechanism for clamping cutting heads on tool holder adapters with several locking elements arranged at equal angles.

[0007] A tool system with balls mounted in a ball cage as locking elements is disclosed in DE 297 08 384 U1.

[0008] From FR-A-1 272 885, a tool holder with a chuck is known, wherein the chuck includes a locking element and the tool has a locking groove. The locking groove can have any shape, including a spiral shape.

[0009] Finally, a tool holder is known from DE 39 39 423 A1 in which a pull-out protection between a base holder and a tool holder is provided by at least two balls in at least two locking grooves, wherein the grooves in the base holder do not have a helical or curved profile.

[0010] The object of the present invention is to provide a system consisting of a tool holder and a rotary tool in which axial migration of the rotary tool, such as round drills, profile drills, screwdrivers including taps, countersinks, milling cutters, etc., is not possible during operation, but rather the rotary tool is held both torque-resistant and axially with respect to the axis of rotation without migration.

[0011] This problem is solved according to the invention by the subject matter of claim 1, wherein further developments of the invention are expediently created by the features in the dependent claims.

[0012] According to the invention, a tool holder according to the invention has a pull-out protection device for the tool, which prevents axial migration of the tool from the tool holder. The pull-out protection device comprises at least one locking element and at least one corresponding locking groove that receives the locking element, and which interact in a positive-locking manner. The locking element and the locking groove are at least partially ball-head shaped, with the tool having the locking groove. Furthermore, the locking groove, which is located at the end face of the tool shank, can be designed with a wider groove width to facilitate easier insertion of the tool into the tool holder.

[0013] In a particularly preferred embodiment, the tool holder has at least two rotatably mounted balls on the tool holder side, with at least two locking grooves corresponding to the balls on the rotary tool shank engaging in a form-fitting manner on the rotary tool side. The two locking grooves are preferably arranged thread-like on the cylindrical tool shank, starting at the end face of the cylindrical shank and extending along its circumferential surface. These locking grooves, located on the circumferential surface of the cylindrical shank of the rotary tool, are counterclockwise for left-handed tools and counterclockwise for right-handed rotary tools. The locking grooves can also be axial and thus parallel to the axis of rotation, which still serves as an anti-rotation device for the tool.

[0014] To clamp the rotary tool according to the invention, such as round drills, profile drills, screwdrivers including taps, countersinks, milling cutters, mandrels for other tools, etc., into the shrink-fit chuck of the tool holder according to the invention, the induction coil is first switched on in the shrink-fit chuck, i.e., the induction coil is subjected to high-frequency alternating current. Due to the eddy currents occurring in the sleeve section of the tool holder, generated by induction from the coil surrounding the tool holder, the sleeve section heats up rapidly, causing it to expand thermally and thus increasing the inner diameter of the receiving opening. The rotary tool can now be inserted into the receiving opening from the shank side. The end face of the rotary tool then comes into contact with the balls projecting into the interior of the receiving opening and abuts against them.Depending on the direction of the locking groove of the rotary tool, it is now rotated either counterclockwise or clockwise with respect to the axis of rotation, allowing the balls to engage in the spherical grooves. Further rotation forces a helical screw-in motion, thus creating an axial pull-in movement of the rotary tool into the shrink-fit chuck or similar device, until the end face of the cylindrical shank abuts the chuck or until the balls in the spherical locking grooves have reached their final position. The induction coil can now be switched off. Due to the rapid cooling that now occurs, the shrink-fit chuck shrinks back to its original size, thereby creating a torque-resistant connection between the cylindrical shank's circumferential surface and the inner circumferential surface of the shrink-fit chuck's receiving opening.Since the direction of rotation of the locking slots corresponds to the direction of rotation of the rotary tools, axial movement of the rotary tool along its axis of rotation is prevented during operation, even under heavy loads, i.e., with high workpiece cutting strength and high tool or table feed rates. The interaction of the balls in the tool holder with the spherical locking slots in the tool shank and the threaded design of these locking slots creates an axial locking mechanism. This axial locking can only be released by rotating the rotary tool in the opposite direction to its working direction while simultaneously withdrawing it from the chuck. However, rotation against the working direction of the rotary tool is not possible during operation, i.e., while the rotary tool is machining a workpiece.Furthermore, this rotational movement is not possible during operation due to the torque-resistant press fit. Therefore, the rotary tool cannot move axially out of the shrink-fit chuck or similar device.

[0015] This ensures precise machining and maintains dimensional accuracy within the required tolerances. Since axial migration is prevented by the present invention, efficient and cost-effective production is possible, as very little scrap is produced compared to conventional toolholders with chucks. Furthermore, this eliminates another potential source of accidents and thus the risk of injury to the machine operator.

[0016] Instead of the balls rotatably press-fitted in the chuck, cylindrical pins with a partial or hemisphere on one end can also be used. These sit in the bearing bore in place of the balls, requiring, for example, either a projecting projection to prevent the cylindrical pin from falling into the interior of the receiving opening, or an external thread that corresponds to the internal thread of the bearing bore. Using balls has the advantage over cylindrical pins with a partial or hemisphere head that inserting the rotary tool is easier, as the balls are rotatably mounted and cannot become misaligned, unlike a cylindrical shank. Balls can also be held in the respective bearing bore using a threaded stud. In this case, the cylindrical stud itself has a feature on its end face to receive the ball, e.g., a threaded stud.in the form of a polygonal recess or a spherical indentation, etc. Instead of the threaded pin, dowel pins, bolts, etc. can also be used.

[0017] The extraction protection device according to the invention for tools, in particular rotary tools in tool holders with a tool receptacle, is particularly suitable for chucks such as collet chucks, HG chucks, hydraulic expansion chucks and shrink-fit chucks.

[0018] Depending on the requirements, the locking grooves in the circumferential surfaces of the tool shank are advantageously designed differently. According to the invention, the locking grooves have different profiles starting from the end face, namely at least a helical or curved profile, or are formed from compound, partially straight and / or curved cylindrical surface paths. In particular, with a helical locking groove profile, the direction of rotation must correspond to the direction of rotation of the grooved tool. That is, for a left-hand grooved tool, the helical locking groove must be inclined to the left, while for a right-hand grooved tool, it must be inclined to the right. This ensures a locking effect of the pull-out protection.

[0019] In another embodiment, the tool shank has an external thread at its end, and the tool holder's receptacle has a corresponding internal thread. In this case, the pull-out protection is achieved using the external thread on the tool, which is left-hand threaded for left-hand grooved tools and right-hand threaded for right-hand grooved tools. In this embodiment, locking elements and the locking groove become obsolete.

[0020] In a particularly preferred embodiment, the bearing bores that receive the locking elements are preferably continuous from the outer circumferential surface of the tool holder into the interior of the tool holder that receives the tool. These bearing bores can be formed perpendicular to and intersecting the axis of rotation of the tool holder and / or tangentially adjacent to the inner circumferential surface of the interior that receives the tool. Preferably, the longitudinal axes of the bearing bores are at the same angle to each other and, in particular, arranged in a plane perpendicular to the axis of rotation of the tool.

[0021] In a further particularly preferred embodiment, the balls are mounted as locking elements in a ball cage. The bearing bores for the respective balls in the ball cage each have a smaller bore diameter on the inner circumferential surface than the bearing bore diameter. This prevents the balls from falling inwards into the interior of the tool holder, but rather causes them to protrude only beyond the inner area of ​​the ball cage. The ball cage can either be inserted into the interior of the tool holder as a separate component with a positive fit, or it can be incorporated into a sleeve. In the latter case, the sleeve has the respective bearing bores with the smaller bearing bore diameters on the side facing the interior.The sleeve can be pressed into the interior of the tool holder, shrunk in, welded to the tool holder, held in a form-fitting manner with additional threaded pins and / or fixed with locking elements and locking grooves on the sleeve, as described according to the invention on the shank of rotary tools.

[0022] In a particularly preferred embodiment, the pull-out protection additionally includes a device that enables the tool to be held securely without play. A force-applying element, which is arranged, for example, concentrically to the tool's axis of rotation at the base of the tool holder's bore, presses the tool out of the tool holder. This ensures that the pull-out protection rests against the tool without any play. Even slight play between the pull-out protection and the tool allows the tool a certain degree of movement, which can lead to damage to the cutting edges. In particular, compression springs in the form of coil springs, conical springs, disc springs, and disc spring assemblies, and / or elastic or rubber-elastic elements are suitable as force-applying elements.

[0023] In a further and particularly advantageous embodiment for a tool holder with minimum quantity lubrication, the tool holder has at least one transfer piece for the minimum quantity lubrication, which includes at least one, preferably several, channels for pressure build-up and pressure equalization. Separate protection is optionally required for such a tool holder with such a transfer piece, independent of the pull-out protection. The transfer piece, preferably in the form of a tube, which may also be composed of several parts, is preferably formed with a radial flange and is preferably movably received and guided in a bore located in the tool holder. The tube, which may also have different cross-sectional profiles, is preferably pre-tensioned in the tool holder by a coil spring, with the cylindrical shaft of the tube preferably penetrating the coil spring.Of course, other force-exerting elements such as tension springs, conical springs, disc springs, and / or elastic elements, as well as combinations thereof, are also possible. The coil spring is preferably arranged between the radial flange of the tube and, for example, a stop base in the tool holder, whereby the tube is pre-tensioned relative to the tool holder. The transfer piece is preferably mounted in the bore with a seal. The tool holder has, concentrically to the bore for the transfer piece or tube, at least one shaft seal and / or other sealing elements such as sealing rings, sealing lips, etc., which can also be arranged in the tool holder and / or on the transfer piece or on the tube itself.The channels, in the form of through-holes, particularly with a circular cross-sectional profile (although other cross-sectional profiles are also possible), are preferably arranged in the radial flange of the transfer piece, such that the through-hole in the transfer piece is connected to the through-hole in the radial flange of the transfer piece. A radial recess is arranged along the cylindrical circumferential surface of the radial flange of the transfer piece. A preferably cylindrical segment-shaped ring membrane corresponding to the radial recess is preferably embedded in this recess in a form-fitting manner. Both the circumferential recess, particularly in the form of a groove, and the preferably corresponding cross-section of the membrane embedded in the groove can, for example, have a partial spherical head profile or other profiles.The ring diaphragm is preferably made of an elastic material, in particular a rubber-elastic material, but other materials are also possible, such as carbon fiber, plastics, Teflon, and flexible metals. The channels for pressure equalization and pressure build-up are connected to the diaphragm and the interior of the transfer piece. When pressure builds up in the tool holder, the diaphragm bulges radially and thus conforms to the circumferential surface of the tool holder's receiving bore. This locks the transfer piece against axial movement.

[0024] Exemplary embodiments of the invention are explained below with reference to drawings. These show, in purely schematic representation: Fig. 1 a sectional view of the tool holder according to the invention with shrink-fit chuck with separate end mill not yet clamped and provided with locking grooves, Fig. 2 a sectional view of the tool holder according to the invention with shrink-fit chuck and clamped end mill according to the invention. Fig. 3 a sectional view of a tool holder not according to the invention with collet chuck and clamped end mill according to the invention. Fig. 4 a sectional view of a tool holder not according to the invention with HG chuck and clamped end mill according to the invention. Fig. 5 a sectional view of a tool holder not according to the invention with hydraulic expansion chuck and clamped end mill according to the invention. Fig. 6 a sectional view of a tool holder not according to the invention with a clamped end mill according to the invention, wherein the tool has an external thread and is screwed into a corresponding internal thread of the tool holder. Fig. 7 a sectional view of the tool holder according to the invention with balls as locking elements which are secured by threaded pins. Fig. 8 a sectional view of the tool holder according to the invention with balls as locking elements which are secured by threaded pins, wherein the balls are partially recessed in the threaded pins. Fig. 9 a sectional view of the tool holder according to the invention with balls as locking elements, secured with cylindrical pins in press fit. Fig. 10 a sectional view of the tool holder according to the invention with a one-piece locking element, which is a threaded pin with a spherical shape on one of its end faces. Fig. 11 a sectional view of the tool holder according to the invention with one-piece locking elements, which are cylindrical pins with a spherical shape on one of the end faces, in press fit. Fig. 12 a sectional view of the tool holder according to the invention with balls in a separate ball cage, a sleeve adjacent thereto. Fig. 13 a sectional view of the tool holder according to the invention with balls which are arranged in a ball cage incorporated in the sleeve, wherein the sleeve is pressed in or shrunk in. Fig. 14 a sectional view of the tool holder according to the invention made of Fig. 13, wherein the sleeve is welded to the tool holder. Fig. 15 a sectional view of the tool according to the invention made of Fig. 13, wherein the sleeve is mechanically fixed with threaded pins with conical dome. Fig. 16 a sectional view of the tool holder according to the invention with slotted sleeve which receives the balls, and the sleeve provided with locking grooves is held on the tool holder via further balls and threaded pins. Fig. 17 a sectional view of the tool holder according to the invention with a conical spring for a backlash-free pull-out protection. Fig. 18 a sectional view of the tool holder according to the invention with a length adjustment screw which is made of rubber-elastic material. Fig. 19. A sectional view of the tool holder according to the invention with a length adjustment screw which has an integrated element made of rubber-elastic material. Fig. 20 a sectional view of the tool holder according to the invention with a minimum quantity lubrication, balls as locking elements and a membrane made of rubber-elastic material. Fig. 21 a sectional view and side view from Fig. 20 of the tool holder according to the invention with tangential arrangement of the locking elements. Fig. 22 an enlarged view of an area from Fig. 20 of the tool holder according to the invention with the membrane and a pressure channel in the transfer piece.

[0025] Fig. Figure 1 schematically shows a sectional view of the tool holder 1 and, by way of example, an end mill 2, which are arranged relative to each other with respect to a rotational axis 3. The tool holder 1 has at least two, preferably three or four balls 4. The ball is located in a bearing bore 5, which is arranged perpendicular to the rotational axis 3 and thus to the longitudinal axis, in the sleeve section 6 of the tool holder 1. This bearing bore 5 is a through bore and extends from the outside of the sleeve section 6 to the inner circumferential surface of the receiving opening 7, which is arranged concentrically to the rotational axis 3 in the tool holder 1. The bearing face 8 of the bearing bore 5 is shaped like a spherical cap and corresponds to the spherical shape of the ball 4, so that the ball 4 partially projects into the interior of the receiving opening 7.The ball 4 is held in its forward position, i.e., in a position projecting into the interior of the receiving opening 7, by a setscrew 9. The bearing bore 5 has an internal thread corresponding to the external thread of the setscrew 9. The length of the setscrew 9 does not extend beyond the outer surface of the sleeve section 6. The setscrew 9 has an internal hexagon socket 10. The end mill 2 has helically arranged locking grooves 13, 14 on its cylindrical shank 11 near the end face 12. These grooves have a spherical profile corresponding to the spherical shape of the ball 4. To fully clamp the end mill in the tool holder, it must be rotated in the direction of rotation 15 when inserted, so that the end mill 2 is screwed axially into the receiving opening 7 until it reaches a stop.

[0026] Fig. Figure 2 shows, purely schematically, in a sectional view, the tool holder 1 in which the end mill 2 is fully clamped. The end mill 2, with its cylindrical shank 11, is located in the receiving opening 7 up to its stop. The ball 4, held by the setscrew 9, engages in the locking groove 13 or 14. In this sectional view, the cylindrical shank 11 is in a press fit with the receiving opening 7; that is, the induction coil (not shown in the drawing) is switched off, and the shrink-fit chuck of the tool holder 1 has cooled down and shrunk back to its original size. As in Fig. As can be clearly seen in Figure 2, axial movement of the end mill 2 along the axis of rotation 3 is not possible because the ball 4 is seated in the spherical locking groove 13 or 14 in the cylindrical shank 11, thus preventing movement along the axis of rotation 3. This drawing clearly illustrates the interaction between the ball 4 and the locking groove 13 or 14 in the form of a locking mechanism. To remove the end mill 2 from the tool holder 1, simply switch on the induction coil and rotate the end mill 2 against the direction of rotation 15 (see Figure 2). Fig. 1) rotated and pulled out of the tool holder 1 in an axial direction along the axis of rotation 3.

[0027] The following figures show possible embodiments of how the pull-out protection is designed in other commercially available chucks.

[0028] Fig. Figure 3 shows a schematic sectional view of an ordinary collet chuck with a union nut and a pull-out protection device provided by the locking groove and balls.

[0029] Fig. Figure 4 shows an HG chuck with a pull-out protection system using a locking groove and balls.

[0030] Fig. Figure 5 shows a purely schematic sectional view of an ordinary hydraulic expansion chuck with a pull-out protection device provided by the locking groove and balls.

[0031] Fig. Figure 6 shows a purely schematic sectional view of a tool holder in the form of a shrink-fit chuck, in which the end mill is screwed to the tool via a thread 16. This screw connection, which is threaded from left to right for left-handed tools and from right to left for right-handed tools, provides axial pull-out protection of the tool from the tool holder.

[0032] Fig. Figure 7 shows a purely schematic sectional view of a shrink-fit chuck with locking elements in the form of balls 4, which are held in the respective bearing bores 5 by threaded pins 9. The threaded pin 9 has a blunt end face.

[0033] Fig. Figure 8 shows a purely schematic sectional view of a shrink-fit chuck with locking elements in the form of balls 4, which are held in the bearing bores 5 by threaded pins 9. The threaded pin 9 has a recess 17 on the end face that receives the ball 4. The recess 17 is formed in the form of a blind hole or, for example, in the form of an internal hexagon socket corresponding to the diameter of the ball.

[0034] Fig. Figure 9 shows a purely schematic sectional view of a shrink-fit chuck with locking elements in the form of balls 4, which are held in the bearing bores 5 by dowel pins 18. Due to the interference fit between the dowel pin 18 and the bearing bore 5, the locking elements in the form of balls 4 are fixed in their position.

[0035] Fig. Figure 10 shows a purely schematic sectional view of a shrink-fit chuck with one-piece locking elements 19. Locking element 19 is a threaded pin which has a hemispherical head 20 on one of its end faces.

[0036] Fig. Figure 11 shows a purely schematic sectional view of a shrink-fit chuck with a one-piece locking element 19 in the bearing bores 5. The one-piece locking elements 19 are dowel pins which are press-fitted to the shrink-fit chuck. The one-piece locking elements 19 have a hemispherical head 20 on one of their end faces.

[0037] Fig. Figure 12 shows a purely schematic sectional view of a shrink-fit chuck with locking elements in the form of balls 4. The balls 4 are mounted in a ball cage 21. The ball cage 21 is located at the base of the receiving opening 7. Adjacent to it is a sleeve 22. The balls 4 are embedded in the cage 21 and are pressed radially outwards by the cage. The balls 4 are pressed against a shoulder located between the receiving opening 7 and a free rotation at the end of the receiving opening 7. The balls 4 can be axially supported by this shoulder. When the tool is shrunk in, the balls 4 are also supported inwards and can thus secure both the tool 2 and the sleeve 22 against axial pull-out.

[0038] Fig. Figure 13 shows a purely schematic sectional view of a shrink-fit chuck with balls 4 located in a sleeve 22, specifically in the left section of the sleeve and in the receiving opening 7. The left section of the sleeve 22 acts as a ball cage for the balls 4. The bearing bores 5 for the balls 4 in the sleeve 22 have a smaller diameter (with respect to the inner cylindrical surface of the sleeve 22) than the diameter of the balls or the bearing bore diameter. Thus, the balls 4 can protrude into the interior but cannot fall in. The sleeve 22 is either shrunk-fit or pressed into the chuck.

[0039] Fig. Figure 14 shows a purely schematic sectional view of a shrink-fit chuck with balls 4 in a sleeve 22. The sleeve 22 is connected to the sleeve section 6 by a weld 23. The weld between the sleeve 22 and the shrink-fit chuck can be spot welds, section welds, or ring welds, for example, a Y-shaped weld.

[0040] Fig. Figure 15 shows a purely schematic sectional view of a shrink-fit chuck with balls 4 in a sleeve 22. In this embodiment, the sleeve 22 is fixed to the tool holder by means of threaded studs 24. The threaded studs 24 have, for example, a conical tip. Of course, other designs, such as a ball head, etc., are also possible. The sleeve 22 has corresponding recesses 25 to the end face of the threaded studs 24, which correspond to the end face of the threaded studs 24. In the present embodiment, these recesses 25 are conical. To fix the sleeve 22 to the tool holder, at least one threaded stud 24 with an end face design, for example, in the form of a cone, is necessary. Preferably, three, and particularly preferably four, threaded studs are arranged to fix the sleeve 22 to the tool holder.

[0041] Fig. Figure 16 shows a purely schematic sectional view of a shrink-fit chuck with locking elements in the form of balls 4 arranged in the sleeve 22. The sleeve 22 is thicker-walled than in the previous figures. Therefore, the sleeve 22 is slotted (not shown in the drawing). In this embodiment, the sleeve 22 is also connected to the tool holder by balls. In the left area of ​​the sleeve 22, there are locking grooves 27 corresponding to the balls, which also have a spherical profile. Just as the tool is axially fixed in the shrink-fit chuck by the interaction of locking elements and locking grooves, in this case the sleeve 22 is axially fixed by means of balls 26 as locking elements with locking grooves 27 in the outer circumferential surface of the sleeve 22. The balls 26 are located in bearing bores 28, which in turn are connected to each other by threaded studs 29.In this case as well, the bearing bore 28 has a smaller diameter in the inner area towards the receiving opening 7 than the bearing diameter, which corresponds to the ball diameter of the ball 26. Therefore, the ball 26 cannot fall into the interior, but rather protrudes into it.

[0042] Fig. Figure 17 shows a purely schematic sectional view of a shrink-fit chuck with an axial pull-out protection according to Fig. 2. Additionally, the tool holder has a conical spring 30 located between the end face 12 of the cylindrical shank 11 of the end mill 2 and the base 31 of the receiving opening 7. The compression spring, in the form of a conical spring 30, presses against the end face 12 of the end mill 2 in the direction of the axis of rotation 3 out of the tool holder 1. This eliminates any potential play or manufacturing tolerances of the locking groove in the circumferential surface of the cylindrical shank 11 and the respective position of the balls 4 in the tool holder 1, insofar as the end mill 2 is additionally locked in the axial direction by the force of the conical spring 3. Thus, even slight play between the axial pull-out protection and the tool can be eliminated. This prevents the risk of damaging the cutting edges during operation due to small manufacturing tolerances.

[0043] Fig. Figure 18 shows a purely schematic sectional view of a shrink-fit chuck with locking elements in the form of balls 4. Here, the backlash-free removal of the tool after shrinking is achieved by using a length-adjusting screw 32, which is preferably made of a rubber-elastic material. A corresponding internal thread 33 is formed in the tool holder for the length-adjusting screw 32. Fig. Figure 18 shows an additional embodiment of the locking groove. In this embodiment, the locking groove 34 is formed in the shape of an "L", but starting at the end face 12 of the cylindrical shaft 11. This creates a bayonet-like locking mechanism for axial locking to prevent the tool from being pulled out of the tool holder.

[0044] Fig. Figure 19 shows a shrink-fit lining in a purely schematic sectional view. Fig. 18, wherein an integrated elastic element 35 is arranged concentrically to the length adjustment screw 32. In this case, the elastic element 35 is preferably made of a rubber-elastic material. The backlash-free pull-out protection is achieved by the contact force exerted on the elastic element 35 via the end face 12 onto the end mill 2 via the length adjustment screw 32.

[0045] Fig. Figure 20 shows a purely schematic sectional view of a shrink-fit chuck with minimum quantity lubrication (MQL). Axial pull-out is prevented by locking elements 36, which are in the form of balls. Concentric to the axis of rotation inside the shrink-fit chuck is a movable tube 37, which serves as the transfer piece for the minimum quantity lubrication. The tube 37 is pressed against the tool shank (not shown in the drawing) by the spring force of a coil spring 38. Fig. Figure 20 shows two possible end positions of the tube 37. The contact surface of the tube with the tool shank on the right is conically shaped in the form of a radial tube flange 39. The spiral spring 38 is concentrically penetrated by the tube 37. The spiral spring 38 is located between the base 31 and the conical circumferential surface of the tube 37 at the radial neck flange. Fig. 21 shows along the intersection line AA from Fig. 20 in a purely schematic sectional view the tangential arrangement of the locking elements 36 in the tool holder. Fig. Figure 22 shows a close-up of a section from Fig.20, which is marked with a dashed line. Through-holes 40 are arranged in the radial neck flange 39 of the tube 37, extending from the inner diameter of the tube 37 to the outer circumferential surface 41 of the radial tube flange 39. A concentric, cylindrical recess 42 is arranged along the cylindrical circumferential surface 41 of the radial tube flange 39 of the tube 37, the width of which is preferably smaller than the width of the cylindrical circumferential surface 41 of the tube flange 39. Corresponding to the recess 42, an annular, cylindrical segment-shaped membrane 43 is arranged, which is flush with the outer cylindrical circumferential surface 41 of the tube flange 39. The membrane 43 is preferably made of a rubber-elastic material. This membrane 43 along the circumferential surface 41 seals the tube 37 against the wall of the receiving opening 7 of the shrink sleeve.The bores 40, which extend radially to the inner surface of the diaphragm 43, transmit the air pressure to the diaphragm 43, which is thus pressed against the bore wall 7. Due to the pressure build-up, the diaphragm bulges radially and thus conforms to the inner circumferential surface of the receiving opening 7 of the tool holder. This secures the tube 37, which serves as the transfer piece for the minimum quantity lubrication, against axial movement. The movable tube 37 allows the lubricating mist to be directed to the tool without loss.

Claims

[1] System of tool holder (1) and rotary tool (2), wherein the tool holder has a chuck with a cylindrical tool receptacle (7) and the cylindrical shank (11) of the rotary tool (2) is received therein, wherein the system has a pull-out protection device that prevents axial migration of the rotary tool due to vibration, which comprises at least one locking element (4, 19) and at least one corresponding locking groove (12, 13) that receives the locking element, wherein the locking groove is arranged in the circumferential surface of the shank of the rotary tool starting from the end face and the locking element is arranged in the chuck, the rotary tool is held torque-resistant by the chuck with an interference fit during operation and axially with respect to the axis of rotation (3) by the pull-out protection device, wherein the locking groove (12, 13) has a locking groove profile which is helical,is curved or formed from compound, partially straight and curved cylindrical surface tracks, wherein it extends at least over a partial section of the shaft (11), such that the locking groove and locking element interact in a form-fitting manner, . characterized by that the rotary tool has at least two, particularly preferably four locking slots, and wherein the chuck is a shrink-fit chuck. [2] System according to one of claims 1, characterized by , that the locking groove (12, 13) are arranged in the circumferential surface of the shaft (11) of the rotary tool (2) and extend starting from the end face. [3] System according to any one of the preceding claims, characterized by , that the helical locking groove profile is formed with a left-hand grooved rotary tool rising to the left and with a right-hand grooved rotary tool rising to the right. [4] System according to any one of the preceding claims, characterized bythat the arrangement of the locking elements in the tool holder and, correspondingly, the arrangement of the locking groove on the rotary tool are at the same angle to each other. [5] System according to any one of the preceding claims, characterized by , that the locking elements in the tool holder are balls, pins, bolts and / or threaded pins which have at least one and at least partially ball-head-like convex end face. [6] System according to any one of the preceding claims, characterized by that the locking elements are stored in bearing bores in the tool holder. [7] System according to any one of the preceding claims, characterized by , that the rotary tool with the pull-out protection is held axially without play by force-exerting elements, in particular with at least one compression spring, conical spring, helical spring, disc spring as well as spring packages, and / or rubber-elastic elements. [8] System according to any one of the preceding claims, characterized by, that the rotary tool with the pull-out protection, especially in chucks with minimum quantity lubrication, is held axially free of play, wherein the transfer piece for the minimum quantity lubrication has at least one through-hole in the conical radial flange area, the radial flange of the transfer piece has a radial recess along its cylindrical circumferential surface, in which a corresponding cylindrical surface section-shaped ring membrane preferably positively and flushly embedded, preferably formed from rubber-elastic material, wherein the through-holes extend radially from the interior of the transfer piece to the membrane. [9] System according to any one of claims 1 to 8, characterized by , that the locking groove profile, in particular the straight axial track section starting at the end face of the tool shank, is designed to be wider with respect to the groove width. [10] System according to any one of claims 1 to 9, characterized by, that the at least one locking element is mounted in a bearing bore in the tool holder, wherein the bearing bore preferably extends continuously from the outer circumferential surface to the interior of the tool holder receiving the rotating tool, and is formed either perpendicular to the axis of rotation of the tool holder and / or tangentially adjacent to the inner circumferential surface of the interior of the tool holder receiving the rotating tool. [11] System according to claim 10, characterized by , that the at least one locking element in the bearing bore is preferably held by a threaded pin and / or by a press fit, and / or the locking element is designed with an external thread which corresponds to the internal thread formed in the bearing bore.

Images