HYDRO-EXPANSION CHUCK AND DRILL FEED UNIT

Description

[0001] The invention relates to a hydraulic expansion chuck and a drilling feed unit.

[0002] Tool applications where there is limited space for accommodating or arranging a tool on a tool holder generally face the problem of changing tools easily and cost-effectively. Typically, such applications require specifically designed adapter pieces that are permanently connected to the tool, for example, shrunk onto the tool. When the tool is replaced, the permanently connected adapter piece is disposed of along with the worn tool. This not only increases material costs, but also involves constantly reconnecting adapter pieces to tools in a permanent manner, typically requiring additional parts and / or materials to create the permanent connection.

[0003] A chuck according to the preamble of claim 1 is known from EP 1 649 956 A1. Another chuck is known from GB 833 048 A.

[0004] These problems arise particularly in connection with drill feed units, such as those used for creating rivet holes in aircraft construction, which are designed to mechanically displace a drill in the axial direction during a drilling process. In such an application, only very limited installation space is available for the mechanical connection of the drill to the drill feed unit, and adapter pieces that are permanently shrunk onto the drill are typically used, with the aforementioned disadvantages.

[0005] There is therefore a need, on the one hand, for a way to clamp tools interchangeably even in confined spaces, and, on the other hand, for a drill feed unit that allows improved drill bit replacement in a simplified, material-saving and cost-effective manner.

[0006] The invention is therefore based on the object of creating a hydraulic expansion chuck and a drill feed unit, wherein the aforementioned disadvantages are alleviated or avoided.

[0007] According to the invention, the object is achieved by providing a hydraulic expansion chuck according to claim 1, which has a clamping receptacle for releasably clamping a tool. Further embodiments emerge from the subclaims. The hydraulic expansion chuck has a maximum width dimension perpendicular to a longitudinal axis of the hydraulic expansion chuck of at least 5 mm to at most 40 mm, preferably of at least 7 mm to at most 35 mm, preferably of at least 10 mm to at most 30 mm, preferably of at least 15 mm to at most 20 mm. In this way, a particularly small hydraulic expansion chuck is provided which can be used to clamp a tool even in confined spaces. Thus, the hydraulic expansion chuck can be used in particular instead of an adapter piece that would otherwise be permanently attached to the tool.

[0008] A longitudinal axis of the hydraulic chuck is, in particular, an axis that extends parallel to a designated longitudinal axis of a tool to be clamped into the clamping fixture in the clamped state, wherein the longitudinal axis of the hydraulic chuck preferably coincides with the longitudinal axis of the tool in the clamped state. Alternatively or additionally, the longitudinal axis of the hydraulic chuck is preferably an axis of the longest extension of the hydraulic chuck.

[0009] The maximum width dimension is therefore preferably measured perpendicular to an axial direction of the tool releasably clamped in the clamping fixture.

[0010] The maximum width dimension is in particular a dimension of the greatest width of the hydraulic expansion chuck perpendicular to the longitudinal axis.

[0011] In particular, the maximum width dimension is preferably an outer diameter of the hydraulic expansion chuck, which is preferably at least partially cylindrical, preferably at least partially circular-cylindrical.

[0012] The design features of the hydraulic chuck described below in connection with preferred embodiments and further developments of the invention are also applicable to preferred embodiments of the hydraulic chuck according to the invention, regardless of the previously described dimensions of the hydraulic chuck. Their combination with the previously described dimensions is particularly preferred.

[0013] In a manner known per se, the hydraulic expansion chuck has a clamping space enclosed by a clamping wall, which is designed to partially accommodate a tool and to clamp the tool in the clamping space. At least one pressure chamber is formed in the clamping wall, which pressure chamber is preferably fillable or filled with a pressurized fluid, in particular a pressurized oil. In a first functional position of the hydraulic expansion chuck, a first pressure value exists in the at least one pressure chamber, wherein an inner surface of the clamping wall is elastically deformed into the interior of the clamping space at the first pressure value, such that a tool arranged in the clamping space is securely and firmly clamped by the deformed inner surface of the clamping wall.In a second functional position of the hydraulic expansion chuck, a second pressure value prevails in the at least one pressure chamber, wherein the inner surface of the clamping wall in the second functional position is not deformed into the clamping space at the second pressure value, but is in particular elastically displaced into a rest state in which the clamping space has a larger internal dimension, in particular a larger internal diameter, than when the inner surface of the clamping wall is deformed into the clamping space in the first functional position. The second pressure value is smaller than the first pressure value. In the second functional position, the tool can be removed from the clamping space or a new tool can be moved into the clamping space. The tool is therefore released in the second functional position. The hydraulic expansion chuck can be reversibly moved from the first functional position to the second functional position - and vice versa.

[0014] The hydraulic expansion chuck is particularly designed for use as an interchangeable chuck of a drilling feed unit according to the invention or of a drilling feed unit according to one of the embodiments disclosed in accordance with the present technical teaching.

[0015] In particular, the clamping fixture is designed for releasably clamping a drill, preferably for such a drilling feed unit.

[0016] According to the invention, the hydraulic chuck has a connecting piece for mechanical connection to a receptacle for the hydraulic chuck, facing away from the clamping receptacle along the longitudinal axis, as well as a centering surface, wherein the centering surface is arranged radially outwardly offset from the connecting piece. In this way, the hydraulic chuck can be connected simply, safely, reproducibly, and stably to a receptacle for the hydraulic chuck, in particular to a drill receptacle and very particularly to an intermediate piece receptacle of a drill feed unit, in particular to a drill feed unit according to the invention or to a drill feed unit according to one of the embodiments disclosed in accordance with the present technical teaching.The connecting piece enables the mechanical connection, while the centering surface simultaneously enables centering and axial alignment of the hydraulic chuck relative to the holder. In particular, this ensures that the longitudinal axis of the hydraulic chuck is aligned or coincides with the axial direction of the holder, especially with the axial direction of the drill feed unit.

[0017] The holder preferably has a counter-centering surface. In particular, the intermediate piece holder preferably has a counter-centering surface. When the hydraulic chuck is attached to the holder, the centering surface rests, in particular, over its entire surface against the counter-centering surface, so that the hydraulic chuck is centered on or in the holder. The fact that the centering surface is arranged radially outwardly offset from the connecting piece contributes particularly favorably to stable and reproducible centering.

[0018] Preferably, the centering surface is also arranged axially offset from the connecting piece relative to the clamping fixture. In particular, it trails the connecting piece in the assembly direction, so that during an assembly process, the connecting piece engages with the fixture first and the centering surface comes into contact with the counter surface last.

[0019] According to a further development of the invention, the connecting piece is designed as a threaded connector. Particularly preferably, the threaded connector is designed as a cylindrical connector with an internal thread, or particularly preferably as a threaded connector with an external thread. It is understood that the threaded connector designed as a cylindrical connector does not necessarily have to have a circular cylindrical geometry. Rather, the basic shape of the cylinder can also deviate from the circular geometry, for example, it can have a polygonal or any other geometry. Thus, the term "cylinder" is used here in its most general form for the extrusion of any flat profile along an extrusion axis. However, the extrusion axis is preferably perpendicular to a profile plane of the profile.

[0020] According to the invention, the centering surface is designed as a truncated cone surface, in particular as an outer truncated cone surface.

[0021] The counter-centering surface, in particular the counter-centering surface of the drill feed unit, is preferably designed as a truncated cone surface, in particular as an internal truncated cone surface. In particular, the centering surface and the counter-centering surface are complementary to each other, so that when the hydraulic chuck is mounted on the holder, they can fully engage and interact with each other.

[0022] According to the invention, it is provided that the at least one pressure chamber is fluidly connected to at least one pressure cylinder, wherein a cylinder longitudinal axis of the at least one pressure cylinder encloses an angle with the longitudinal axis of the hydraulic chuck that is from at least 0° to at most 3°, preferably from at least 1° to at most 2°, preferably 1.5°. This enables, in particular, the miniaturized, very small design of the hydraulic chuck, since the pressure cylinder is arranged in a space-saving manner parallel to the longitudinal axis or at a small acute angle to the longitudinal axis of the hydraulic chuck and can thus be integrated into the hydraulic chuck very close to the longitudinal axis in the radial direction.In conventional, larger hydraulic chucks, the longitudinal axis of a pressure cylinder typically has a much larger angle to the longitudinal axis of the hydraulic chuck, whereby the longitudinal axis of the pressure cylinder can, in particular, be perpendicular to the longitudinal axis of the hydraulic chuck. This requires significantly more installation space.

[0023] A pressure piston is preferably displaceably arranged in the at least one pressure cylinder. By displacing the pressure piston in the pressure cylinder, the volume available for the pressure fluid can be changed, so that the pressure fluid can be pressurized in the first functional position and relieved in the second functional position relative to the first functional position. The first pressure value and the second pressure value can therefore be provided in particular by suitable displacement of the pressure piston in the pressure cylinder, wherein the pressure piston in the pressure cylinder leaves a smaller volume free for the pressure fluid in the first functional position, thus being displaced into the pressure cylinder, whereas in the second functional position it releases a larger volume for the pressure fluid, thus being displaced a certain distance out of the pressure cylinder or in the pressure cylinder away from the pressure chamber.

[0024] According to the invention, a pressure screw bore is assigned to the at least one pressure cylinder. A longitudinal axis of the pressure screw bore is aligned parallel to the longitudinal axis of the pressure cylinder. This enables particularly simple actuation of the pressure piston in the pressure cylinder via the pressure screw bore.

[0025] Alternatively or additionally, the longitudinal axis of the pressure screw bore is arranged perpendicular to the cylinder's longitudinal axis, offset from the cylinder's longitudinal axis. The longitudinal axis of the pressure screw bore is therefore not aligned with the cylinder's longitudinal axis, but rather is offset perpendicularly to it, in particular parallel to it. This configuration, in particular, allows for a particularly small installation space for the hydraulic expansion chuck. The pressure screw bore has a larger diameter than the pressure cylinder, so that it occupies a comparatively large installation space perpendicular to the longitudinal axis or cylinder's longitudinal axis.

[0026] The longitudinal axis of the pressure screw bore is arranged offset in particular radially inwards towards the longitudinal axis of the hydraulic expansion chuck relative to the cylinder longitudinal axis, so that as a result the pressure screw bore can have at most a small oversize radially outwards relative to an outermost position of the pressure cylinder.

[0027] The pressure screw bore is particularly configured to accommodate a pressure screw, which in turn is configured to influence the pressure in the pressure cylinder and thus simultaneously in the at least one pressure chamber. In particular, the pressure screw bore is operatively connected to the pressure cylinder; particularly preferably, the pressure screw is operatively connected to the pressure piston for its actuation. In particular, the pressure screw is in contact with the pressure piston, so that the pressure piston can be displaced in the pressure cylinder by displacing the pressure screw, in particular by screwing the pressure screw in and / or out of the pressure screw bore or into it.

[0028] The pressure screw is preferably designed as a grub screw. It preferably has an actuating engagement through which a torque can be introduced into the pressure screw. In a preferred embodiment, the actuating engagement is designed as a hexagon socket.

[0029] According to a further development of the invention, the pressure chamber is fluidically connected to a plurality of pressure cylinders. This enables a further reduction in the size of the hydraulic expansion chuck. Typically, a certain displacement path of the pressure piston in the pressure cylinder is required to achieve a volume displacement sufficient to clamp the tool stably and firmly in the clamping chamber. If this volume displacement is to be achieved by only one pressure cylinder, this requires a certain minimum length for the pressure cylinder in the axial direction. However, if a plurality of pressure cylinders are provided that are fluidically connected to the same pressure chamber, the various pressure cylinders jointly contribute to the volume displacement, so that each individual pressure cylinder can be built shorter because a correspondingly reduced displacement path must be maintained for the individual pressure pistons.The hydraulic expansion chuck can therefore be made smaller in the axial direction.

[0030] According to a further development of the invention, the at least one pressure screw bore opens into the centering surface. Thus, the centering surface can be used, in an advantageous and particularly space-saving manner, both for centering the hydraulic expansion chuck and for actuating the at least one pressure screw in the at least one pressure screw bore.

[0031] According to a preferred embodiment, the hydraulic chuck has at least two pressure cylinders, in particular exactly two pressure cylinders, or exactly three pressure cylinders. These can be provided symmetrically distributed along a circumferential line on the hydraulic chuck. However, it is also possible for the hydraulic chuck to additionally have at least one, preferably exactly one, balancing bore; preferably, the pressure cylinders and pressure screw bores together with the balancing bore are then arranged symmetrically along the circumferential line, in particular at equal angular distances from one another. In particular, it is possible for three pressure screw bores / pressure cylinders to be arranged at an angular distance of 90° each along the circumferential line, wherein the balancing bore in the thus resulting fourth quadrant is arranged at an angular distance of 90° each from the pressure screw bores / pressure cylinders immediately adjacent to it.

[0032] According to a further development of the invention, the hydraulic chuck has at least two wrench flats for introducing a torque into the hydraulic chuck, wherein the wrench flats are preferably formed on an outer circumferential wall of the hydraulic chuck, in particular in the region of the clamping receptacle. A tool, in particular a wrench, can engage the wrench flats in order to screw the hydraulic chuck with the connecting piece, in particular the threaded connector, into a receptacle or to screw it onto the receptacle. Particularly preferably, six wrench flats in the form of an external hexagon are provided, in particular at that end of the hydraulic chuck at which the clamping receptacle is provided, thus opposite the connecting piece along the longitudinal axis.

[0033] According to a preferred embodiment, the hydrogen chuck is manufactured additively, in particular by 3D printing, in particular by means of powder-bed-based, layer-by-layer melting of a metal powder, in particular by means of laser radiation, in particular by laser sintering or laser beam melting. In this way, the hydraulic chuck can be manufactured in one piece in a simple manner despite its comparatively complex geometry.

[0034] The hydraulic chuck preferably has an insertion chamfer or rounded portion on the clamping receptacle, in particular at the opening of the clamping chamber. This serves to facilitate the insertion of a tool, in particular a drill, into the clamping chamber.

[0035] Preferably, a circumferential surface of the hydraulic chuck is cylindrical, in particular circularly cylindrical, at least in some areas. Particularly preferably, the hydraulic chuck is circularly cylindrical overall, preferably with the exception of the centering surface, the connecting piece, and / or the key surfaces. In particular, the hydraulic chuck is circularly cylindrical with respect to the outer circumferential surface from the centering surface to the key surfaces—viewed in the longitudinal direction—i.e., it has a fully cylindrical, circularly cylindrical circumferential surface. This represents a particularly advantageous geometry, especially for confined installation spaces.

[0036] Further according to the invention, the object is achieved by providing a drilling feed unit according to claim 7. Further embodiments emerge from the further subclaims.

[0037] The drilling feed unit has a drill holder that is configured to fasten a drill to the drilling feed unit. The drilling feed unit also has a feed device that is configured for the mechanical displacement of the drill holder relative to a housing of the drilling feed unit in the axial direction. The drill holder has an interchangeable chuck that is configured for the releasable fastening - i.e. for clamping in particular a cylindrical drill shank - of the drill to the interchangeable chuck. With the aid of the interchangeable chuck, it is possible to change the drill in a simple and cost-effective manner, whereby neither additional complex and sometimes expensive materials and / or tools are required for changing the drill, nor does an adapter piece that is permanently connected to the drill have to be provided, which would then be disposed of together with the drill.Rather, the drill can be easily removed from the interchangeable chuck and a new drill can be clamped into the interchangeable chuck.

[0038] The drill chuck is particularly designed for the movable attachment of the drill to the drill feed unit, whereby the drill can be mechanically displaced relative to the housing along with the drill chuck. In this way, the drill is advanced in the axial direction by the feed device.

[0039] The drill chuck is particularly configured for the indirect attachment of the drill to the drill feed unit, in which case the drill chuck itself is not designed as an interchangeable chuck, but rather is configured for attaching the interchangeable chuck to the drill chuck. However, it is also possible for the drill chuck itself to be designed as an interchangeable chuck, in which case it is configured for the direct attachment of the drill to the drill feed unit.

[0040] An axial direction is understood here, in particular, to mean a direction that extends along a longitudinal direction of the drill and, in particular, along a feed direction defined by the feed device and by the intended displacement of the drill holder relative to the housing, which can be effected by the feed device. To drill a hole, the drill is rotated in a manner known per se about its longitudinal axis and displaced along its longitudinal axis, i.e., in the axial direction. A radial direction is perpendicular to the axial direction, and a circumferential direction encompasses the axial direction concentrically.

[0041] The housing preferably accommodates the drill chuck. Alternatively or additionally, the housing accommodates the feed mechanism. In particular, the housing preferably encompasses the drill chuck and / or the feed mechanism, at least in part.

[0042] According to a further development of the invention, the drill holder comprises an intermediate piece holder and an intermediate piece, wherein the intermediate piece is configured to be mechanically connected at one end, i.e., at a first end, to the intermediate piece holder and at the other end, i.e., at a second end opposite the first end along a longitudinal axis of the intermediate piece, preferably in the axial direction, to a drill. The intermediate piece is the interchangeable chuck of the drill feed unit for releasably securing the drill—in particular for clamping a cylindrical drill shank, in particular.In this case, the drill holder is configured to indirectly fasten the drill to the drill feed unit, with the intermediate piece holder being configured to fasten the intermediate piece to the intermediate piece holder, with the intermediate piece in turn being configured as an interchangeable chuck to releasably clamp the drill. In particular, the intermediate piece is configured to be fastened to the intermediate piece holder at one end and to fasten the drill to the intermediate piece at the other end. The intermediate piece is designed as an interchangeable chuck, particularly at the second end.

[0043] In a particularly simple manner, to change the drill bit, the adapter can first be separated from the adapter holder and then the drill bit can be removed from the adapter. A new drill bit can then be clamped into the adapter, which is designed as an interchangeable chuck, and the adapter is then reattached to the adapter holder. This makes it possible, in particular, to remove the adapter from the adapter holder and thus the drill bit holder in order to change the drill bit, thus creating more space for operating the interchangeable chuck. A user of the drill feed unit therefore does not have to work in the confined space of the drill holder area in order to change the drill bit.At the same time, the intermediate piece represents an adapter piece which does not have to be disposed of together with a worn-out drill bit, but rather is reused by removing a worn-out drill bit from the interchangeable chuck and clamping a new drill bit into the interchangeable chuck.

[0044] According to a further development of the invention, the intermediate piece has a connecting piece at one end, in particular at the first end, which is designed to mechanically connect the intermediate piece to the intermediate piece receptacle. At the other end, in particular at the second end, the intermediate piece has a clamping receptacle for releasably clamping the drill. Thus, the second end is designed as an interchangeable chuck.

[0045] According to a preferred embodiment, the connecting piece is designed as a threaded connector which is configured to screw the intermediate piece onto the intermediate piece receptacle.

[0046] The threaded connector at the first end enables particularly easy connection of the intermediate piece to the intermediate piece holder by screwing or screwing.

[0047] The threaded connector is preferably designed as a cylindrical socket with an internal thread, or, more preferably, as a threaded socket with an external thread. The intermediate piece receptacle accordingly has either a complementary external thread for screwing into the cylindrical socket with an internal thread, or a complementary internal thread for screwing into the threaded socket with an external thread. It is understood that the threaded connector designed as a cylindrical socket does not necessarily have to have a circular cylindrical geometry. Rather, the basic shape of the cylinder can also deviate from the circular geometry, for example, have a polygonal or any other geometry. Thus, the term "cylinder" is used here in its most general form for the extrusion of any flat profile along an extrusion axis. However, the extrusion axis is preferably perpendicular to a profile plane of the profile.

[0048] According to a further development of the invention, the interchangeable chuck is selected from a group consisting of a hydraulic chuck, a collet chuck, a polygonal chuck, and a face chuck. All of these chucks are suitable for the releasable fastening of a drill. A suitable embodiment of a hydraulic chuck is described in more detail according to the present technical teaching. An interchangeable chuck designed as a collet chuck preferably has elastic clamping tongues in the radial direction, which can be selectively moved into a clamping position and a release position by a clamping cap or clamping nut.A polygonal chuck has a polygonal geometry that can be expanded by applying external pressure or force to release a tool from the chuck or insert a new tool into the chuck. Removal of the external pressure or force causes the polygonal chuck to return to a clamping configuration in which the tool is clamped in the polygonal chuck. A face chuck, in particular, has a clamping pin or a clamping screw that, in a clamping position, cooperates with a clamping surface of a tool to clamp the tool in the face chuck. The tool can be released from the face chuck by moving the clamping pin or the clamping screw to a release position.

[0049] According to a further development of the invention, the drill holder is arranged at least partially in a housing section of the housing. The drill holder is thus arranged internally within the housing, so that only a very limited space is available for attaching the drill. The housing section is preferably a distal housing section, i.e., a housing section that is intended to face a workpiece to be machined. The drill holder is preferably displaceable within the housing section and relative to the housing section.

[0050] Preferably, the drill holder is arranged at least partially in the housing section with the intermediate piece holder and preferably also with the intermediate piece. Particularly preferably, the drill holder is arranged at least partially in the housing section with the intermediate piece holder, the intermediate piece, and the drill.

[0051] According to a further development of the invention, the interchangeable chuck, in particular the intermediate piece, has a maximum width dimension ranging from at least 5 mm to at most 40 mm, preferably from at least 7 mm to at most 35 mm, preferably from at least 10 mm to at most 30 mm, preferably from at least 15 mm to at most 20 mm. Thus, the interchangeable chuck is very small, particularly relative to the dimensions of known interchangeable chucks, and is suitable for use in very confined spaces, particularly in a drill feed unit. The width dimension is measured in particular perpendicular to the axial direction. A maximum width dimension is understood to mean the greatest extent of the interchangeable chuck perpendicular to the axial direction. The maximum width dimension is particularly preferably a maximum outer diameter of the interchangeable chuck, which is preferably at least partially cylindrically symmetrical, preferably circularly cylindrical.

[0052] According to a further development of the invention, the housing section is detachably connected to an upper housing, wherein the housing section can be separated from the upper housing in order to replace the drill. Separating the housing section from the upper housing enables access to the drill receptacle and thus, in particular, replacing the drill from the drill receptacle. In particular, separating the housing section from the upper housing enables access to the intermediate piece receptacle and the intermediate piece in order to separate the intermediate piece from the intermediate piece receptacle. After replacing the drill on the intermediate piece, the intermediate piece can be reconnected to the intermediate piece receptacle, after which the housing section can be reconnected to the upper housing.

[0053] Preferably, the feed device is arranged in the upper housing and remains in the upper housing during the replacement of the drill.

[0054] According to the invention, it is provided that the interchangeable chuck, in particular the intermediate piece, is designed as a hydraulic expansion chuck according to the invention.

[0055] The advantages described here are realized in a special way.

[0056] A method for changing a drill bit on a drill feed unit comprises the following steps: A first drill bit is removed from a changeable chuck of the drill feed unit, and a second drill bit is clamped into the changeable chuck of the drill feed unit. This method enables a simple, quick, and cost-effective change of a drill bit on a drill feed unit, in particular without having to dispose of an adapter piece along with the drill bit.

[0057] Within the scope of the method, a drilling feed unit according to the invention is preferably used.

[0058] Within the scope of the method, a hydraulic expansion chuck according to the invention is preferably used as the interchangeable chuck. First, an intermediate piece designed as an interchangeable chuck is removed from an intermediate piece holder together with the first drill bit. Subsequently, while the intermediate piece is separated from the intermediate piece holder, the first drill bit is released from the intermediate piece. Subsequently, the second drill bit is clamped into the intermediate piece, after which the intermediate piece—with the second drill bit—is mechanically reconnected to the intermediate piece holder.

[0059] Preferably, a housing section of the drill feed unit encompassing the intermediate piece is first separated from an upper housing, making the intermediate piece accessible. The intermediate piece is then removed from the intermediate piece holder together with the first drill. The first drill is then removed from the intermediate piece. The second drill is then clamped into the intermediate piece, and then the intermediate piece—with the second drill—is reattached to the intermediate piece holder. Finally, the housing section is reconnected to the upper housing.

[0060] Disassembly of the intermediate piece includes, in particular, unscrewing the intermediate piece from the intermediate piece holder or unscrewing the intermediate piece from the intermediate piece holder. Mechanically connecting the intermediate piece to the intermediate piece holder includes, in particular, screwing the intermediate piece into or onto the intermediate piece holder.

[0061] By separating the intermediate piece, which is designed in particular as a hydraulic expansion chuck, from the intermediate piece receptacle, the clamping mechanism becomes accessible in a preferred embodiment; in particular, a clamping tool, for example a hexagon wrench, can engage the at least one pressure screw, in particular when it opens into the centering surface, wherein the centering surface and thus the pressure screw bore become accessible when the intermediate piece is disassembled from the intermediate piece receptacle.

[0062] The invention is explained in more detail below with reference to the drawings, which show: Figure 1 shows an illustration of an example of a drilling feed unit according to the prior art; Figure 2 shows a detailed illustration of an exemplary embodiment of a drilling feed unit according to the invention; Figure 3 shows an illustration of an exemplary embodiment of a hydraulic chuck according to the invention in longitudinal section; Figure 4 shows a side view of the hydraulic chuck according to Figure 3 ; Figure 5 a view of the hydraulic chuck according to the Figures 3 and 4 from below, and Figure 6 a three-dimensional representation of the hydraulic expansion chuck according to the Figures 3 to 5 .

[0063] Fig. 1shows an illustration of an example of a drilling feed unit 1 according to the prior art. The drilling feed unit 1 has a drill holder 3 for attaching a drill 5 to the drilling feed unit 1, as well as a feed device 7 configured for mechanically displacing the drill holder 3 relative to a housing 9 of the drilling feed unit 1 in the axial direction, i.e., in the direction of a longitudinal axis A.

[0064] To connect the drill 5 to the drill holder 3, an adapter piece 110 is provided here, which can be screwed into the drill holder 3 with a threaded connector 130, which for this purpose has an internal thread complementary to an external thread of the threaded connector 130. The adapter piece 110 is permanently connected to the drill 5, in particular shrunk onto the drill 5. To replace the drill 5, it is unscrewed from the drill holder 3 with the adapter piece 110 and disposed of together with the adapter piece 110. A new drill 5 with a new adapter piece 110 is then screwed into the drill holder 3. This is, on the one hand, cumbersome because an adapter piece 110 must first be shrunk onto each drill to be used, and, on the other hand, it is material-intensive and expensive because the adapter pieces 110 are disposed of together with the drills 5.

[0065] Fig. 2shows a detailed representation of an embodiment of a drilling feed unit 1. Identical and functionally equivalent elements are identified by the same reference numerals as in Figure 1, so that reference is made to the description therein. In the exemplary embodiment of the drilling feed unit 1 according to the invention, it is provided that the drill holder 3 has an interchangeable chuck 15. The drill 5 is detachably connected to the interchangeable chuck 15, in particular clamped therein, so that in order to replace the drill 5 it is possible to remove it from the interchangeable chuck 15 and thus separate it from the interchangeable chuck 15, wherein a new drill 5 can then be inserted into the interchangeable chuck 15 and clamped therein. In contrast to the adapter piece 110, it is therefore no longer necessary to dispose of a part that is permanently connected to the drill 5 together with the latter.This eliminates the associated material and cost expenditure, as well as the additional expenditure that arises from the fact that each new drill 5 has to be assigned its own adapter piece 110 and, in particular, has to be laboriously shrunk onto it.

[0066] In particular, the drill holder 3 here has an intermediate piece holder 17 and an intermediate piece 11, wherein the intermediate piece 11 is configured to be mechanically connected at a first end 19 to the intermediate piece holder 17 and at a second end 21, opposite the first end 19 along the longitudinal axis A, to the drill 5. In this case, the intermediate piece 11 is designed as an interchangeable chuck 15 for releasably securing the drill 5. In particular, the intermediate piece 11 is the interchangeable chuck 15, or in other words: the interchangeable chuck 15 forms the intermediate piece 11 or is identical to the intermediate piece 11.

[0067] Thus, the intermediate piece 11 particularly preferably replaces the adapter piece 110 known from the prior art, but it can be detachably connected to the drill 5 and is therefore reusable.

[0068] The intermediate piece 11 preferably has a connecting piece 22, here a threaded connector 23 at the first end 19, wherein the threaded connector 23 is configured for screwing the intermediate piece 11 onto the intermediate piece receptacle 17. In a preferred embodiment, the threaded connector 23 is designed here as a threaded socket 13. In this respect, in a particularly preferred embodiment, the threaded socket 13 is designed analogously to the threaded socket 130 of the known adapter piece 110 and is thus configured to match the drill receptacle 3 of an otherwise known drill feed unit 1, so that the intermediate piece 11 and thus the interchangeable chuck 15 can also be used with existing drill feed units 1 as a retrofit solution.

[0069] As an alternative to a threaded connector 13 with an external thread, the threaded connector 23 can also be designed as a cylindrical connector with an internal thread, or in another suitable manner. Of course, this requires a corresponding, complementary design of the drill holder 3 or the provision of a suitable adapter.

[0070] At the second end 21, the intermediate piece 11 has a clamping receptacle 25 for releasably clamping the drill 5.

[0071] The functionality of such a drilling feed unit 1 is preferably as follows: On the drilling feed unit 1, a contact surface 27 is formed, which serves to place the drilling feed unit 1 against a workpiece surface in order to be able to drill a hole in the workpiece with high precision. During the production of the hole, the contact surface 27 remains in constant contact with the surface of the workpiece, while the drill 5 is displaced by the feed device 7 relative to the housing 9 and thus simultaneously also relative to the contact surface 27. Unlike with a freehand drilling machine guided without contact with the workpiece, a precisely aligned drilling of the hole is thus possible. The feed device 7 is preferably designed as a pneumatic feed device, wherein its Figure 1a pneumatic connection 29 is assigned. To produce the bore, the drill 5 is set in a rotational movement about the longitudinal axis A, whereby in particular the drill holder 3 is set in rotation, taking the drill 5 with it. For this purpose, the drill holder 3 is again with reference to Figure 1a motor drive 31 is assigned to the housing 9. This can also be a pneumatic drive. Of course, other drive concepts are possible for both the motor drive 31 and the feed device 7, for example an electric drive, a hydraulic drive, or any other type of suitable drive. In particular, a manual drive is also conceivable in principle for at least one of the movement modes. The housing 9 also has a suction connection 33, which can be fluidly connected to a suction device (not shown here) in order to suction chips out of the area of ​​the resulting bore. The chips are preferably conveyed through at least one chip space of the drill 5, which is wound along a helical line, from the resulting bore in the direction of the suction connection 33. The drilling feed unit 1 can be handheld or attached to a robot arm.Of course, other possibilities for holding and / or guiding the drilling feed unit 1 are also possible. Such a drilling feed unit 1 is used in particular in aircraft construction, preferably for drilling rivet holes.

[0072] The housing 9 accommodates the drill holder 3 and the feed device 7. At the same time, the housing 9 encloses at least in the Figure 2 The retracted state of the drill 5 shown also largely reflects this.

[0073] According to a preferred embodiment of the invention, the intermediate piece 11 and thus the interchangeable chuck 15 are designed as hydraulic chucks in accordance with the invention. In particular, a hydraulic chuck designed in this way allows for use even in confined spaces, such as the interior of the housing 9 of the drill feed unit 1.

[0074] Alternatively and not within the scope of the invention, it is possible that the intermediate piece 11 and thus also the interchangeable chuck 15 are designed as another hydraulic expansion chuck, as

[0075] Collet, as a polygon chuck, as a face chuck or in another suitable manner, in particular as another chuck.

[0076] The drill holder 3 is preferably arranged at least partially in a housing section 35 of the housing 9. The housing section 35 is in particular a distal housing section, i.e. a housing section that is intended to face a workpiece to be machined. In particular, the drill holder 3 is displaceable in the housing section 35. The intermediate piece holder 17, as well as the intermediate piece 11 and the drill 5, are preferably also arranged at least partially in the housing section 35, preferably displaceable therein. The housing section 35 is here detachably connected to an upper housing 37 of the housing 9. The housing section 35 can be separated from the upper housing 37 in order to replace the drill 5. The feed device 7 is in particular arranged in the upper housing 37.To separate the housing section 35 from the upper housing 37, a manually operable separating mechanism 39 is provided in the embodiment shown here, by means of which a connection between the housing section 35 and the upper housing 37 can be unlocked, so that the housing section 35 can be separated from the upper housing. In a particularly simple embodiment, the separating mechanism 39 comprises a finger lever 41 that is urged into a locking position under spring preload and can be displaced into an unlocking position against the spring preload. This finger lever 41 can be actuated quickly and easily by a user of the drilling feed unit 1 - in particular with a finger - similar to the trigger of a handgun.

[0077] To change the drill 5, preferably first the interchangeable chuck 15 and thus the intermediate piece 11 are separated from the drill holder 3 and thus from the intermediate piece holder 17, in particular by unscrewing, whereby the interchangeable chuck 15 is removed from the drill feed unit 1 together with the drill 5. Then, outside the drill feed unit 1, the drill 5 is released from the interchangeable chuck 15. Then a new drill 5 is inserted, in particular clamped, into the interchangeable chuck 15. Then the interchangeable chuck 15 with the new drill 5 is again fastened to the drill holder 3 and at the same time to the intermediate piece holder 17, in particular by screwing or screwing in. In a particularly preferred embodiment, the housing section 35 is first separated from the upper housing 37, whereby the interchangeable chuck 5 becomes accessible so that it can be released from the drill holder 3.When the housing section 35 is separated from the upper housing 37, the interchangeable chuck 15 with the new drill 5 can then be attached to the drill holder 3. Afterward, the housing section 35 is preferably reattached to the upper housing 37 or connected to the upper housing 37.

[0078] The intermediate piece 11 has a maximum width dimension, in particular a maximum outer diameter, of at least 5 mm to at most 40 mm, preferably of at least 7 mm to at most 35 mm, preferably of at least 10 mm to at most 30 mm, preferably of at least 15 mm to at most 20 mm. The width dimension is measured in particular perpendicular to the extension of the longitudinal axis A. In this way, the intermediate piece 11 is dimensioned such that it can be used in the confined space inside the housing 9 of the drilling feed unit 1.

[0079] Fig. 3shows a longitudinal section through an embodiment of a hydraulic chuck 200. The hydraulic chuck has a clamping fixture 225 for releasably clamping a tool. Furthermore, the hydraulic chuck 200 has a maximum width measured perpendicular to a longitudinal axis A' of at least 5 mm to at most 40 mm, preferably of at least 7 mm to at most 35 mm, preferably of at least 10 mm to at most 30 mm, preferably of at least 15 mm to at most 20 mm. Thus, the hydraulic chuck 200 is very small in terms of its maximum width and can therefore also be used in confined spaces. In a preferred embodiment, the maximum width is a maximum outer diameter of the hydraulic chuck 200. The longitudinal axis A' preferably extends parallel to the longitudinal axis of a tool inserted into the clamping fixture 225.

[0080] The hydraulic expansion chuck 200 is particularly designed for use as an interchangeable chuck 15 of a drill feed unit 1 according to the technical teaching disclosed herein. In a preferred embodiment, the interchangeable chuck 15 of the drill feed unit 1, and thus also the intermediate piece 11, is the hydraulic expansion chuck 200 disclosed here. In a preferred embodiment, the longitudinal axis A' of the hydraulic expansion chuck 200 is aligned with the longitudinal axis A of the drill feed unit 1 or coincides with it when the hydraulic expansion chuck 200 is inserted into the drill feed unit 1, in particular when it is fastened to the drill holder 3, that is, in particular, to the intermediate piece holder 17, as the intermediate piece 11.

[0081] However, the hydraulic chuck 200 and the drill feed unit 1 can also be used separately. In particular, the hydraulic chuck 200 can be used independently of the drill feed unit 1 in other applications. In particular, the drill feed unit 1 can be used with another interchangeable chuck, independently of the hydraulic chuck 200.

[0082] The clamping holder 225 has a clamping space 205 enclosed by a clamping wall 203. At least one pressure chamber 207 is formed in the clamping wall 203, which can be filled, preferably is filled, with a pressurized fluid, in particular a pressurized oil. In a first functional position of the hydraulic expansion chuck 200, a first pressure prevails in the pressure chamber 207, at which an inner surface 209, starting from a relaxed position, is elastically deformed into the clamping space 205, whereby a tool, in particular a drill, partially arranged in the clamping space 205 can be clamped by the deformed inner surface 209.In a second functional position of the hydraulic chuck 200, a second pressure prevails in the pressure chamber 207, which is lower than the first pressure, at which the inner surface 209 is arranged in its relaxed position, so that the clear inner diameter of the clamping space 205 is larger than in the first functional position, and the tool is released and can thus be removed from the clamping space 205. Of course, a new tool can be inserted into the clamping space 205 in the second functional position in a similar manner, and can then be clamped by moving the hydraulic chuck 200 from the second functional position to the first functional position. The basic functioning of such a hydraulic chuck 200 is known per se, so it will not be discussed in detail here.

[0083] The hydraulic chuck 200 has, along its longitudinal axis A', a connecting piece 222 for mechanical connection to a receptacle for the hydraulic chuck 200, in particular at a first end 219, facing away from the clamping receptacle 225, and also a centering surface 211. The centering surface 211 is arranged radially outwardly offset from the connecting piece 222. A radial direction is perpendicular to the longitudinal axis A' of the hydraulic chuck 200. At the same time, the centering surface 211 is also arranged axially offset from the connecting piece 222, in particular offset in the direction of the clamping receptacle 225. The clamping receptacle 225 is arranged at a second end 221 opposite the first end 219 along the longitudinal axis A'.

[0084] The connecting piece 222 is preferably designed as a threaded connector 223. The threaded connector 223 is preferably designed as a threaded socket 213 with an external thread 231. Alternatively, the threaded connector 223 can also be designed as a cylindrical socket with an internal thread, or in another suitable manner. The connecting piece 222 can also be designed in another suitable manner, for example, as a clamping stub or in another suitable shape.

[0085] The centering surface 211 is designed as a truncated cone surface. Particularly preferably, it is complementary to a counter-centering surface 43 of the drill holder 3, in particular the intermediate piece holder 17, of the drill feed unit 1, so that the hydraulic chuck 200 is centered on the drill holder 3 when the centering surface 211, in particular, bears fully against the counter-centering surface 43. The connecting piece 222 serves to axially fix the hydraulic chuck 200 on the drill holder 3, with the centering surface 211 serving for alignment and centering.

[0086] The counter-centering surface 43 is preferably also designed as a truncated cone surface of an inner cone. The centering surface 211 is correspondingly the truncated cone surface of an outer cone.

[0087] For better installation and centering, a clearance 233 is formed between the connecting piece 222 and the centering surface 211.

[0088] The at least one pressure chamber 207 is fluidically connected to at least one pressure cylinder, here to two pressure cylinders 235, 235'. A cylinder longitudinal axis Z of the pressure cylinder 235 encloses an angle of at least 0° to a maximum of 3°, preferably of at least 1° to a maximum of 2°, preferably of 1.5°, with the longitudinal axis A' of the hydraulic chuck 200. This preferably applies to each pressure cylinder 235, 235', wherein in particular each cylinder longitudinal axis Z of a pressure cylinder 235, 235' encloses the same angle with the longitudinal axis A' of the hydraulic chuck 200. For the sake of clarity, only one cylinder longitudinal axis Z is shown here for the Figure 3 left pressure cylinder 235. Due to this configuration of the pressure cylinders 235', 235, the hydraulic expansion chuck 200 can be designed to be very compact and space-saving, especially in the direction perpendicular to its longitudinal axis A', i.e., to the width direction.

[0089] In each of the pressure cylinders 235, 235', a pressure piston (not shown here) can be displaced, wherein by displacing the pressure piston along the respective cylinder longitudinal axis Z, the pressure fluid in the pressure chamber 207, which is at least partially also arranged in the pressure cylinders 235, 235', can be pressurized or released.

[0090] Each pressure cylinder 235, 235' is assigned a pressure screw bore 237, 237'. The respective pressure screw bore 237, 237' is operatively connected to the pressure cylinder 235, 235' assigned to it for influencing the pressure of the pressure fluid in the pressure cylinder 235, 235' and thus also in the pressure chamber 207. In particular, a pressure screw (not shown here) is arranged in the pressure screw bore 237, 237', wherein the respective pressure cylinder can be displaced in the direction of the respective cylinder longitudinal axis Z by screwing the pressure screw in or out. In a preferred embodiment, the pressure screw is designed as a grub screw and preferably has an actuating engagement, in particular a hexagon socket engagement.

[0091] A bore longitudinal axis B of the pressure screw bore 237, 237' extends parallel to the cylinder longitudinal axis Z of the associated pressure cylinder 237, 237'. Alternatively or additionally, here additionally, the bore longitudinal axis B is arranged perpendicular to the cylinder axis Z and offset therefrom, in particular radially inwardly offset parallel to the longitudinal axis A' of the hydraulic expansion chuck 200. This allows a particularly space-saving design of the hydraulic expansion chuck 200 - particularly in the width direction. In this respect, it is relevant that the pressure screws typically have a diameter that is larger than the diameter of the pressure pistons, so that the pressure screw bores 237, 237' also have a larger diameter than the pressure cylinders 235, 235'.If the cylinder longitudinal axes Z and the bore longitudinal axes B were to coincide, more installation space would have to be provided for the pressure screw bores 237, 237' in the width direction, i.e., in the radial direction. However, actuation of the pressure pistons by the pressure screws is also possible if they are not centered relative to the pressure cylinders. Therefore, installation space can be saved in the width direction by arranging the pressure screw bores 237, 237' offset radially inward relative to the pressure cylinders 235, 235' in the direction of the longitudinal axis A' of the hydraulic expansion chuck 200.

[0092] Furthermore, the pressure chamber 207 is preferably fluidically connected to a plurality of pressure cylinders 235, 235'. The volume displacement and pressure increase in the pressure chamber for the first functional position can then be achieved by displacing a plurality of pressure pistons, whereby the axial displacement path for each individual pressure piston is reduced while achieving the same volume displacement and ultimately the same pressure difference. Thus, the fluidic connection of the pressure chamber 207 to a plurality of pressure cylinders 235, 235' also contributes to a particularly small installation space for the hydraulic expansion chuck 200. In particular, the hydraulic expansion chuck 200 can be designed to be shorter - and at the same time, due to the angle of the cylinder longitudinal axes Z to the longitudinal axis A' of the hydraulic expansion chuck 200, also smaller in the width direction - than would be the case if the pressure chamber 207 were fluidically connected only to a pressure cylinder 235, 235'.

[0093] In a preferred embodiment, the at least one pressure screw bore 237, 237' opens into the centering surface 211. This enables a particularly compact installation space for the hydraulic expansion chuck 200. At the same time, it can be seen that, particularly when the hydraulic expansion chuck 200 is used as an interchangeable chuck 15, in particular as an intermediate piece 11, in a drill feed unit 1, the pressure screw bores 237, 237' and thus the pressure screws are only accessible when the intermediate piece 11 is separated from the intermediate piece receptacle 17 and thus, at the same time, the centering surface 211 is separated from the counter-centering surface 43. Therefore, preferably, the drill 5 is first separated together with the intermediate piece 11 from the intermediate piece receptacle 17, wherein the drill 5 is then released from the interchangeable chuck 15, here the hydraulic expansion chuck 200.A new drill 5 can then be clamped into the interchangeable chuck 15, here the hydraulic expansion chuck 200, whereby the interchangeable chuck 15 together with the drill 5 can then be fixed to the intermediate piece holder 17 and can be centered in particular via the centering surface 211 and the counter-centering surface 43.

[0094] Fig. 4 shows a side view of the hydraulic expansion chuck 200 according to Figure 3Identical and functionally equivalent elements are provided with the same reference numerals in all figures, so that reference is made to the preceding description in each case. The hydraulic chuck 200 preferably has a cylindrical, in particular circular-cylindrical, outer peripheral surface 239. The hydraulic chuck 200 is preferably fully cylindrical, in particular except for the area of ​​the connecting piece 222, the key surfaces 241 explained in more detail below, of which only one is designated with the reference numeral 241 for the sake of clarity, and the conical centering surface 211.The key surfaces 241 serve in particular to enable a tool, in particular a key, to engage the hydraulic chuck 200 - in particular in the region of the second end 221 - in order to screw the hydraulic chuck 200 with the connecting piece 222 into a receptacle for the hydraulic chuck 200, in particular into the intermediate piece receptacle 17 of the drilling feed unit 1.

[0095] The hydraulic expansion chuck 200 preferably has more than two pressure cylinders 235, 235' and correspondingly also more than two pressure screw bores 237, 237', 237", in the embodiment shown here in particular three pressure screw bores 237, 237', 237", which open into the centering surface 211.

[0096] Fig. 5 shows a view of the hydraulic expansion chuck 200 according to the Figures 3 and 4from below. The three pressure screw bores 237, 237', 237" are visible here. These are arranged at an angular distance of 90° from each other in three quadrants. In the fourth quadrant, a balancing bore 243 is arranged at an angular distance of 90° from the immediately adjacent pressure screw bores 237, 237'.

[0097] It is evident in Figure 5 also the key area 241, which in Figure 4 is marked with the corresponding reference symbol. Overall, Figure 5 It can be seen that the hydraulic expansion chuck 2 has six wrench surfaces 241 which form an external hexagon.

[0098] Fig. 6 shows a three-dimensional view of the hydraulic expansion chuck 200 according to the Figures 3 to 5The external hexagon formed by the key surfaces 241, as well as the cylindrical outer peripheral surface 239, are clearly visible here. Furthermore, it can be seen that the hydraulic chuck 200 has an insertion chamfer 245 in the region of the second end 221 in the opening area to the clamping chamber 205, which can also be designed as an insertion rounding. The insertion chamfer 245 or insertion rounding allows for easier insertion of a workpiece, in particular a drill 5, into the clamping chamber 205.

[0099] The hydraulic chuck 200 is preferably manufactured additively, particularly preferably by 3D printing, in particular by laser sintering or laser beam melting. This makes it particularly easy to form the hydraulic chuck 200 with the geometric features described here.

[0100] With reference to Figure 3The hydraulic expansion chuck 200 preferably also has a central channel 247, through which the clamping chamber 205 is accessible from the first end 219, in particular through the connecting piece 222. This central channel 247 is preferably configured to allow coolant / lubricant transport to a tool arranged in the clamping chamber 205.

Claims

1. Hydro expansion clamping chuck (200), with - a clamping receptacle (225) for releasably clamping a tool, wherein - the clamping receptacle (225) comprises a clamping space (205) enclosed by a clamping wall (203), wherein at least one pressure chamber (207) is arranged in the clamping wall (203), wherein - the pressure chamber (207) is fluidically connected to at least one pressure cylinder (235, 235') of the hydro expansion clamping chuck, wherein - a cylinder longitudinal axis (Z) of the at least one pressure cylinder (235, 235') forms an angle with the longitudinal axis (A') of the hydro expansion clamping chuck (200) which is at least 0° and at most 3°, wherein - a pressure screw hole (237, 237', 237") is assigned to the at least one pressure cylinder (235, 235'), wherein a borehole longitudinal axis (B) of the pressure screw hole (237, 237', 237") is a) parallel oriented to the cylinder longitudinal axis (Z) of the pressure cylinder (235, 235'), and / or b) offset from the cylinder longitudinal axis (Z) in a direction perpendicular to the cylinder longitudinal axis (Z) of the pressure cylinder (235, 235'), wherein - the pressure screw hole (237, 237', 237") comprises a larger diameter than the pressure cylinder (235, 235'). characterized in that - the hydro expansion clamping chuck (200) comprises a maximum width dimension of at least 5 mm to at most 40 mm perpendicular to a longitudinal axis (A') of the hydro expansion clamping chuck (200), that - the hydro expansion clamping chuck (200) comprises, along the longitudinal axis (A') of the clamping receptacle (225) facing away from the clamping receptacle (225), a connection piece (222) for mechanical connection to a receptacle for the hydro expansion clamping chuck (200) and a centering area (211), wherein the centering area (211) is arranged radially outwardly offset relative to the connection piece (222), and that - the centering area (211) is configured as a truncated cone area.

2. Hydro expansion clamping chuck (200) according to claim 1, characterized in that the connection piece (222) is configured as a threaded connector (223).

3. Hydro expansion clamping chuck (200) according to one of the preceding claims, characterized in that the angle which the cylinder longitudinal axis (Z) of the at least one pressure cylinder (235, 235') encloses with the longitudinal axis (A') of the hydro expansion clamping chuck (200) is from at least 1° to at most 2°, preferably 1.5°.

4. Hydro expansion clamping chuck (200) according to one of the preceding claims, characterized in that the maximum width dimension of the hydro expansion clamping chuck (200) is from at least 7 mm to at most 35 mm, preferably from at least 10 mm to at most 30 mm, preferably from at least 15 mm to at most 20 mm.

5. Hydro expansion clamping chuck (200) according to one of the preceding claims, characterized in that the pressure chamber (207) is fluidically connected to a plurality of pressure cylinders (235, 235').

6. Hydro expansion clamping chuck (200) according to one of the preceding claims, characterized in that the at least one pressure screw hole (237, 237', 237") opens into the centering area (211).

7. Drill feed unit (1), with - a drill bit receptacle (3) for fastening a drill bit (5) to the drill feed unit (1), and with a - feed device (7) for mechanically displacing the drill bit receptacle (3) relative to a housing (9) of the drill feed unit (1) in axial direction, wherein - the drill bit receptacle (3) comprises an interchangeable clamping chuck (15) for releasably fastening the drill bit (5), characterized in that - the interchangeable clamping chuck (15) is configured as a hydro expansion clamping chuck (200) according to one of the claims 1 to 6.

8. Drill feed unit (1) according to claim 7, characterized in that the drill bit receptacle (3) comprises an intermediate piece receptacle (17) and an intermediate piece (11), wherein the intermediate piece (11) is adapted to be mechanically connected at one end to the intermediate piece receptacle (17) and at the other end to the drill bit (5), wherein the intermediate piece (11) is configured as the interchangeable clamping chuck (15) for releasably fastening the drill bit (5).

9. Drill feed unit (1) according to one of the claims 7 or 8, characterized in that the intermediate piece (11) comprises a connecting piece (22) at one end for mechanical connection to the intermediate piece receptacle (17) and a clamping receptacle (25) at the other end for releasable clamping of the drill bit (5).

10. Drill feed unit (1) according to one of the claims 7 to 9, characterized in that the drill bit receptacle (3) is arranged at least in regions in a housing portion (35) of the housing (9), preferably is displaceable in the housing portion (35).

11. Drill feed unit (1) according to one of claims 7 to 10, characterized in that the interchangeable clamping chuck (15) has a maximum width dimension of at least 7 mm to at most 35 mm, preferably of at least 10 mm to at most 30 mm, preferably of at least 15 mm to at most 20 mm.

12. Drill feed unit (1) according to one of claims 7 to 11, characterized in that the housing portion (35) is separably connected to an upper housing (37), wherein the housing portion (35) can be separated from the upper housing (37) in order to replace the drill bit (5).