Oscillating machine tool, tool, coupling element and system

Abstract

Oscillatingly driven machine tool with a housing (12) in which a motor (26), a tool spindle (18) with a tool holder (31) for fastening a tool (20), and an oscillation drive (36) are accommodated, wherein the oscillation drive (36) is driven by the motor (26) and is coupled to the tool spindle (18) for the rotationally oscillating drive about its longitudinal axis (19), and with at least one controllable actuator (44, 46, 48, 50) in order to superimpose at least one movement component on the rotational oscillation movement of the tool spindle.

Description

[0001] The invention relates to an oscillating machine tool, comprising a housing in which a motor, a tool spindle with a tool holder for fastening a tool, and an oscillation drive are accommodated, wherein the oscillation drive is driven by the motor and is coupled to the tool spindle for its rotationally oscillating drive about its longitudinal axis.

[0002] Such a machine tool is known, for example, from EP 1 358 965 A2.

[0003] Machine tools of this type can be used to perform a wide variety of tasks, including sawing, cutting, and grinding. The tool is typically driven at a high oscillation frequency, approximately in the range of 5,000 to 30,000 oscillations per minute (approximately 83 to 500 Hz), with a small tilt angle, approximately in the range of 0.5° to 7° (measured from reversal point to reversal point). This enables highly precise machining of workpieces. The oscillating tool generates only low reaction forces or counter-torques when machining workpieces, which must be absorbed by the machine tool operator. Compared to rotary-driven sawing tools, such as circular saws, oscillating-driven saw blades pose a significantly lower risk of injury to the user.In addition, elongated saw blades can be used to make plunge cuts, particularly in workpieces made of wood, GRP, plaster or the like, which is only possible to a limited extent with rotating tools.

[0004] However, plunge cuts pose the problem that the chip spaces quickly become clogged with chips. Furthermore, the saw blade, which does not cut sideways but only oscillates, is forced laterally during plunge cuts, preventing it from oscillating. The oscillation is thus shifted to the gear box, the chuck, and the saw blade itself, stressing the parts through elastic deformation or being converted into frictional heat.

[0005] DE 10 2010 028 233 A1 discloses a reciprocating saw or jigsaw whose sawing motion can be superimposed by a micro-working motion. To this end, the drive unit of the reciprocating saw or jigsaw has an excitation actuator with a volume of excitation-active material to generate the micro-working motion. The superimposition of the sawing motion with the micro-working motion is intended to enable improved cutting results and smoother, more precise saw control.

[0006] DE 10 2011 101 075 A1 discloses a hand-driven power tool with improved vibration damping. For this purpose, the power tool comprises a device designed for vibration damping, which is embodied as an inertial mass exciter. The device comprises a movably mounted inertial mass driven by an actuator such that a first natural frequency of the inertial mass exciter lies below the vibration frequency of the power tool to be damped.

[0007] From DE 20 2012 011 311 U1 a saw blade for an oscillatory driven machine tool is known, which has linear or strip-shaped impressions, which positively influence the tension properties of the saw blade and consequently the natural frequency and the propagation of vibration waves.

[0008] Sawing brittle materials, such as ceramics, stone, glass, and fiber composites, is currently virtually impossible with an oscillating machine tool. During sawing, the tool usually wears out faster than the machining progresses.

[0009] Against this background, the invention is based on the object of improving a machine tool of the type mentioned above in such a way that more effective machining of various materials, especially brittle materials, is possible. Preferably, adaptation to different material types and machining tasks should be possible.

[0010] This object is achieved according to the invention in an oscillatingly driven machine tool according to the type mentioned at the outset in that at least one controllable actuator is provided in order to superimpose at least one controllable movement component on the rotary oscillation movement of the tool spindle.

[0011] The object of the invention is achieved in this way.

[0012] According to the invention, the movement additionally generated by the controllable actuator superimposes one or more additional motion components on the rotary oscillation movement of the tool spindle. The controllable design of the actuator allows for a wide range of adaptation options to different materials and different machining tasks.

[0013] According to a first embodiment of the invention, the at least one controllable actuator is coupled to the tool spindle or the oscillation drive.

[0014] Thus, the actuator acts directly on the tool spindle or on the oscillation drive, so that a direct motion superposition can be achieved.

[0015] According to a further embodiment of the invention, the at least one actuator acts in the housing and on the tool spindle, preferably in the region of a bearing of the tool spindle.

[0016] In this way, the tool spindle can be specifically actuated by means of the actuator in order to achieve a targeted influence on the tool movement depending on the respective material and the machining task.

[0017] For this purpose, the at least one actuator can act on the tool spindle in such a way that it executes a movement with at least one movement component that lies outside a radial plane spanned by the longitudinal axis of the tool spindle.

[0018] Such an influence on the tool spindle occurs, for example, when the tool spindle is actuated via its bearing at only one end by an actuator, while the tool spindle at the other end is not actuated by an actuator. In this case, there is no parallel displacement of the tool spindle, but rather a tilting of the tool spindle at one end.

[0019] According to a further embodiment of the invention, at least one movement component is superimposed on the tool spindle in a radial plane spanned by the longitudinal axis of the tool spindle.

[0020] Such an influence on the tool spindle can be achieved, for example, using two actuators that act on the two bearings supporting the tool spindle. If both actuators are operated synchronously, this results in a displacement of the tool spindle parallel to its longitudinal axis.

[0021] It goes without saying that further actuators can also be provided, for example two opposing actuators that act on the tool spindle on both sides of the tool spindle, for example via their bearings.

[0022] With such a design, the tool spindle can be moved in a targeted manner both in one direction and in the opposite direction via the actuators. If the actuators on one bearing and the other bearing of the tool spindle are not operated synchronously, in addition to the motion component in a radial plane spanned by the longitudinal axis of the tool spindle, further motion components can be generated that lie outside this radial plane.

[0023] Furthermore, it is understood that a plurality of actuators can be provided which are arranged in such a way that several movement components are superimposed on the tool spindle in a radial plane spanned by the longitudinal axis of the tool spindle or also further movement components which lie outside a radial plane spanned in such a way.

[0024] For example, further actuators could be provided which are offset by 90°, for example, with respect to the first four actuators which lie in one plane.

[0025] Depending on how the various actuators are controlled, specific movements of the tool spindle can result, for example, corresponding to a circular movement of the tool spindle around a center point or an additional linear oscillation of the tool spindle parallel to its longitudinal axis. Any number of other combinations are conceivable.

[0026] According to a further embodiment of the invention, at least one actuator is arranged on the tool spindle and in the housing in such a way that a movement component in the axial direction is superimposed on the tool spindle.

[0027] Such excitation of the tool spindle can also be advantageous for individual machining cases and materials.

[0028] According to a further embodiment of the invention, the machine tool has at least one inertial mass, on which the at least one actuator acts in the housing and on the inertial mass.

[0029] Such an arrangement is particularly advantageous for higher excitation frequencies.

[0030] Preferably, the inertial mass is suspended from the housing in a flexible manner, preferably by means of a plurality of spring elements.

[0031] Depending on the direction in which the suspension is carried out by means of the spring elements in the housing, the direction of action of the actuator on the inertial mass must also be selected accordingly.

[0032] For example, an arrangement can be selected in which the at least one actuator acts on the inertial mass in such a way that it is movable in a radial plane spanned by the longitudinal direction of the tool spindle.

[0033] Of course, several actuators can also be provided here, which act on the inertial mass in different directions, in which case additional suitable suspensions on the housing by means of spring elements are preferably also provided.

[0034] According to a further embodiment of the invention, an actuator is provided on the tool itself. This allows a conventional machine tool with a conventional oscillation drive to be used, while the targeted influence on the tool is generated by a superimposed movement directly on the tool.

[0035] In this way, an even more targeted influence on the tool movement can be achieved if necessary.

[0036] A certain disadvantage arises from the fact that the tool is equipped with an actuator, which must be disposed of when the tool is replaced, resulting in correspondingly increased costs. Furthermore, the tool must be supplied with power from the machine tool via a suitable interface to activate the actuator.

[0037] According to a further embodiment of the invention, a coupling element is provided which is fastened to the tool spindle and on which the at least one actuator is received, wherein the coupling element has a first receptacle for fastening to the tool spindle and a second receptacle for releasably fastening a working element to the coupling element.

[0038] In this way, the disadvantage of the previously explained design is eliminated, since at least one actuator always remains on the coupling element and only the working element needs to be replaced when it wears out.

[0039] For this purpose, the coupling element can have a first region on which the first receptacle is designed for connection to the tool spindle, and a second region on which the second receptacle is designed for receiving the working element, wherein the at least one actuator is arranged between the two regions.

[0040] Advantageously, the two areas can be connected to each other by at least one elastic element.

[0041] According to a further embodiment of the invention, an interface for the (electrical) connection to the machine tool is provided on the tool or on the coupling element.

[0042] In this way, the energy supply of at least one actuator on the tool or the coupling element is ensured.

[0043] According to a further embodiment of the invention, the tool is designed as a sawing tool, in particular for sawing brittle tools, such as ceramics, stone, glass, fiber composite materials such as GRP, etc.

[0044] Although the tool can, in principle, be any tool, the invention is particularly suitable for tools designed as sawing tools, especially for sawing brittle workpieces such as ceramics, stone, glass, and fiber composites. Of course, the invention is also fundamentally suitable for processing other materials, such as sawing high-strength metals.

[0045] In principle, any type of actuator is conceivable. The at least one actuator can thus comprise a piezo element, a nanotube element, an electrodynamic element, or a fluid element.

[0046] In particular, a design of the at least one actuator as a piezo actuator leads to a particularly cost-effective and effective embodiment of the invention.

[0047] According to a further embodiment of the invention, a controller is provided which is coupled to the actuator in order to periodically excite the at least one actuator.

[0048] In this way, a targeted excitation of the actuator is made possible by superimposing one or more targeted periodic movements of the actuator on the oscillation movement generated by the oscillation drive.

[0049] Preferably, the at least one actuator can be excited with a variable excitation frequency, which allows a targeted influencing of the tool behavior, which can be particularly advantageously adapted to specific machining tasks and oscillation frequencies of the oscillation drive.

[0050] According to a further embodiment of the invention, the actuator can be subjected to an excitation signal so that an excitation frequency results which is greater than an oscillation frequency of the oscillation drive.

[0051] For example, if the oscillation drive is operated at a frequency of 325 Hz (19,500 oscillations per minute), an excitation frequency for the at least one actuator in the range of 500 to 700 Hz, particularly approximately 600 Hz, is important. By variably adjusting the oscillation frequency for the excitation signal of the at least one actuator, a targeted adaptation to the material being processed and the respective processing task can be achieved, thus achieving optimized sawing behavior, for example, when sawing GRP.

[0052] In addition to the frequency of the excitation signal, a targeted adjustment of the signal shape can also be generated via the machine tool's control system. This could, for example, be a sinusoidal or rectangular excitation signal. Any other periodic signal shapes are conceivable, whereby other signal shapes, such as harmonic frequencies, can also be superimposed, or individual pulse sequences, such as longer and shorter signals, signals with a steeper or weaker rise, with different edge shapes, etc., are also conceivable.

[0053] According to a further embodiment of the invention, an actuator is provided on the machine tool for switching the at least one actuator on and off and preferably for adjusting the frequency, the amplitude and / or the shape of the excitation signal, optionally by means of a further actuator.

[0054] In this way, at least one actuator can be switched on or off in a targeted manner and the signal shape, amplitude or frequency can be specifically adapted to the respective work task.

[0055] According to a further variant, the frequency, amplitude, and / or shape of the excitation signal of the at least one actuator is automatically adjusted during a work process, for which purpose certain parameters, such as force, pressure, frequency, temperature, and the like, can be recorded and taken into account. Alternatively, a presetting for specific material classes can also be performed manually.

[0056] The invention further provides a tool with an actuator for applying an excitation signal to the tool in at least one direction, wherein the actuator is coupled to an electrical interface which is designed for coupling to a machine tool with an oscillation drive for the rotationally oscillating drive of a tool spindle, and with a holder for fastening the tool to the tool spindle.

[0057] Furthermore, the invention provides a coupling element with an electrical interface and a receptacle for connection to a tool spindle of a rotary oscillating driven machine tool, and with a tool receptacle for releasably fastening a working element to the coupling element, wherein at least one actuator is provided between the receptacle and the tool receptacle, which is connected to the electrical interface, wherein the tool receptacle is preferably connected to the receptacle via at least one elastic element.

[0058] According to a further embodiment of the invention, the workpiece itself is driven in an oscillating manner in order to superimpose a further movement on the drive movement of a conventional rotary oscillating driven machine tool.

[0059] The invention is thus also achieved by a system with an oscillatingly driven machine tool having a housing in which a motor, a tool spindle with a tool holder for fastening a tool and an oscillation drive are located, wherein the oscillation drive is driven by the motor and is coupled to the tool spindle for its rotationally oscillating drive about its longitudinal axis, and with an external workpiece carrier for receiving a workpiece, which has a second oscillation drive.

[0060] It is understood that the features of the invention mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the invention.

[0061] Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. Fig. 1 a perspective view of a machine tool according to the invention with an oscillation drive and integrated actuator, wherein a sawing tool is accommodated at the lower end of the tool spindle; Fig. 2 a schematic representation of the machine tool according to Fig. 1; Fig. 3 a modification of the machine tool according to Fig. 2 in schematic representation; Fig. 4 a coupling element for attachment to a machine tool similar to Fig. 1 with an integrated actuator and a holder for fastening a working element; Fig. 5 a sawing tool with integrated actuator for attachment to a machine tool of the type described above and Fig. 7 a schematic representation of an alternative system for sawing workpieces, in which the workpiece is mounted on an oscillatingly driven workpiece holder and is machined by means of an oscillatingly driven machine tool.

[0062] In Fig. 1 shows a machine tool according to the invention in perspective and is designated overall by the number 10.

[0063] The machine tool 10 has an elongated housing 12, the rear part of which is designed as a handle 14, with an electrical connection cable 15 indicated at the end. A gear head 16 with an oscillation drive 36 is indicated at the front part of the housing 12, with a tool spindle 18 projecting downward from the end of the gear head 16 perpendicular to the longitudinal axis of the housing 12.

[0064] The tool spindle 18 can be driven in a rotationally oscillating manner about its longitudinal axis 19, as indicated by the double arrow 28. At the lower end of the tool spindle 18, a tool 20 in the form of a saw is mounted, on which a straight cutting edge 21 is provided.

[0065] On the top of the housing 12, a switch 22 is provided for switching the machine tool 10 on and off. At the front end of the gear head 16, a switch 23 is indicated, which can be used to switch an actuator on and off, as described in more detail below. At the end of the housing 12 opposite the gear head 16, an adjusting knob 24 can also be seen, which serves as an actuator for setting various parameters of an excitation signal for the actuator, as described below.

[0066] The machine tool 10 is designed as a handheld machine tool. Instead of being powered by mains power, it could, of course, also be powered by a rechargeable battery.

[0067] A first embodiment of the machine tool 10 is described below with reference to Fig. 2 is explained in more detail.

[0068] The motor 26 is housed in the handle area 14 of the housing 12. The motor 26, which may be a universal motor, is connected to a central control unit 42.

[0069] The motor 26 drives the oscillation drive 36, via which the rotational movement of the motor shaft is converted into a rotary oscillation movement of the tool spindle 18 about its longitudinal axis 19. For this purpose, the motor shaft of the motor 26 drives an eccentric 38, which is coupled to the tool spindle 18 in a generally known manner via an eccentric bearing and an eccentric lever 40, whereby the rotary movement of the motor shaft is converted into the rotary oscillation movement of the tool spindle 18 (see, for example, EP 1 358 965 A2, which is hereby incorporated in its entirety by reference).

[0070] The tool spindle 18 is supported at both ends by means of a rolling bearing 32 and 34.

[0071] At the outer end of the tool spindle 18, a tool holder 31 is formed, to which the tool 20 can be positively secured and additionally secured by means of a fastening element 30, for example in the form of a screw.

[0072] According to the invention, an additional actuator 44 is now provided, which is directly coupled to the outer ring of the lower bearing 34 facing the tool 20. The actuator 44 is designed, for example, as a piezo actuator and thus comprises a piezo stack which, when excited by a suitable voltage signal, generates a movement transverse to the longitudinal axis 19 of the tool spindle 18, as indicated by the arrow 52.

[0073] On the opposite side, another, identically constructed actuator can be arranged, as indicated by the dashed line 50. Furthermore, further actuators 46, 48 can be arranged on both sides of the other bearing 32, as indicated by the dashed line. The actuators 44 to 50 can act directly on the outer bearing ring or can act indirectly, for example, on a sleeve in which the two bearings 32, 34 are held and which is slidably received on the housing 12, for example by means of a guide. Any other mechanical constructions are conceivable for coupling the actuators 44 to 50 to the tool spindle 18 or the bearings 33, 34.

[0074] Furthermore, it is understood that additional actuators can be arranged in other planes. For example, four additional actuators could act on bearings 32 and 34 in a direction perpendicular to the plane of the drawing, so that they are angularly offset by 90° from the other bearings 44 to 50.

[0075] The actuators 44 to 50 are coupled to the central controller 42 in such a way that they are activated by a periodic excitation signal. Preferably, the excitation signals of the actuators 44 to 50 are synchronized in such a way that the tool spindle 18 experiences a displacement parallel to its longitudinal axis 19. As shown in Fig. 2, four actuators 44 to 50 are provided, the tool spindle 18 can only be moved back and forth in an oscillating manner in one direction, namely perpendicular to the longitudinal axis 19, in the direction of the plane of the drawing.

[0076] If the tool 20, as previously explained, is driven in a rotary oscillation about the longitudinal axis 19 of the tool spindle 18 via the oscillation gear 36, a combined movement results at the cutting edge 21 from the rotary oscillation movement about the longitudinal axis 19 in conjunction with a linear back-and-forth oscillating displacement of the cutting edge 21, as indicated by the arrow 53. The sawing movement caused by the rotary oscillation is thus superimposed with a linear oscillating movement in the feed direction.

[0077] This leads to significantly improved cutting results and improved chip removal. This is particularly noticeable when sawing brittle materials such as ceramics, stone, glass, and fiber-reinforced plastics such as GRP.

[0078] If additional actuators are provided, for example, two actuators each on bearing 32 and two actuators on bearing 34, which are arranged in a plane offset by 90° from the plane of the drawing, any desired movements of the tool spindle 18 can be generated with respect to a longitudinal axis fixed to the device. For example, the tool spindle 18 could be moved in a circular motion around the longitudinal axis or along a path deviating from a circular path, with any combination of these possible.

[0079] The actuators 44 to 50 can be switched on or off using the switch 23.

[0080] In addition, it may be possible to adjust the frequency and amplitude of the excitation signal and, if necessary, even the shape of the excitation signal, which is done via the adjustment knob 24.

[0081] Preferably, the frequency of the excitation signal is higher than the frequency of the oscillation drive 36. If the oscillation gear oscillates at a frequency of 325 Hz, for example, the frequency of the excitation signal could be 600 Hz, for example. As mentioned above, an optional adjustment option for the frequency and amplitude of the excitation signal can also be provided.

[0082] For example, it can be a sinusoidal or rectangular excitation signal. Other signal shapes are also conceivable, possibly with additional superimposed oscillations and possibly with a variation of the signal shape, for example, by means of individual signal peaks and varying signal amplitudes.

[0083] Various signal shapes, frequencies, and amplitudes can be programmed, which can be automatically called up via the controller 42, for example, to ensure optimized sawing behavior of the tool 20 depending on the material to be machined. The adjustment can be carried out automatically and controlled via suitable sensors that record, for example, the cutting force amplitude, the pressure, or similar on the tool spindle 18. Alternatively, a suitable presetting could be made via the adjustment knob 24 depending on the material to be machined.

[0084] If further actuators are arranged in further planes of the tool spindle 18, any spatial displacements of the tool spindle 18 parallel to its longitudinal axis 19 with different curve shapes can be generated.

[0085] On the other hand, it is also possible to actuate the tool spindle 18 only on one side via one or two actuators 44, 50, which leads to a certain pendulum movement, which in turn can be advantageous for certain machining tasks.

[0086] A modification of the design according to Fig. 2 will be explained below using Fig. 3. The machine tool 10a according to Fig. 3 differs from the machine tool 10 described above according to Fig. 2 in that instead of actuators that act directly on the tool spindle 18, an inertial mass 54 is provided.

[0087] The inertial mass 54 is suspended in a spring-loaded manner at the rear end of the housing 12 in the handle part 14 via four spring elements 58, 59, 60, 61 and is movable in the direction of the longitudinal axis 56 by means of an actuator 44, as indicated by the arrow 62. The inertial mass 54 is suspended in a spring-loaded manner only in the longitudinal direction 56 of the housing 12 by means of the spring elements 58 to 61. Thus, one actuator 44 is sufficient to drive the inertial mass 54 in an oscillating manner in the longitudinal direction 56. Alternatively or additionally, the inertial mass 54 could be suspended in a direction perpendicular thereto, i.e., according to Fig. 3 between the upper and lower ends of the housing 12. In this case, at least one actuator would act on the inertial mass 54 in the corresponding direction.

[0088] In Fig. Figure 4 shows a further embodiment of the invention. Instead of an actuator accommodated in the machine tool, a tool 20a is provided, which is equipped with an actuator 44. The tool 20a has a receptacle 65 in the form of a fastening opening, which is designed for positive fastening to an associated tool holder 31 of the tool spindle 18 of the machine tool 10b. The actuator 44 is connected via connecting lines 72 to an electrical interface 71 near the receptacle 65.

[0089] When fastening the tool 20a to the tool spindle 18, the interface 71 on the tool 20a interacts with an associated interface 84 on the tool spindle 18 ( Fig. 5) to ensure an energy supply to the actuator 44 on the tool 20a.

[0090] In this case, when changing the tool 20a, the actuator 44 applied to it must also be disposed of.

[0091] A variant of this is in Fig. 6 shown.

[0092] Fig. 6 shows a coupling element 63 with an actuator 44, on which a working element 70 is exchangeably received.

[0093] For this purpose, the coupling element 63 has a first region 64, in which a receptacle 65 in the form of a fastening opening is provided for connection to a correspondingly shaped raised tool holder 31 on the tool spindle 18 of the machine tool 10b. The first region 64 is connected via two external elastic elements 66 to a second region 67, in which a receptacle 68 is formed for the releasable fastening of the working element 70, on which a cutting edge with a saw toothing is formed in the manner described above.

[0094] The receptacle 68 is provided for the releasable attachment of the working element 70, with locking being effected by means of fastening elements 69, which are only schematically indicated. The actuator 44 is arranged between the two areas 64, 67, which in turn is coupled to an interface 71 in the immediate vicinity of the receptacle 65.

[0095] When the coupling element 63 is fastened to the tool spindle 18, the interface 71 of the coupling element 63 is again electrically connected to the associated interface 84 on the tool spindle 18, so that the actuator 44 on the coupling element 63 can be controlled via the associated control of the machine tool 10b.

[0096] Compared to the execution according to Fig. 4, the advantage is that the actuator 44 does not have to be disposed of with the tool every time the tool is changed, but rather remains permanently on the coupling element 63. In addition, further variation options for influencing the impressed oscillation movement on the processing element 70 arise, since the actuator 44 is not only applied to the surface of the tool 20a, as is the case with the embodiment according to Fig. 4 is the case.

[0097] A further modification of the invention is described below with reference to Fig. 7 explained.

[0098] Here, the workpiece 78 is clamped onto a workpiece carrier 76 by means of a clamping device 74. The workpiece carrier 76 can be driven in an oscillating manner by means of an oscillation drive 82. The workpiece 78 can be driven in an oscillating manner by the oscillation drive 82, approximately in the direction of arrow 80 in the longitudinal direction, or in other directions, or, for example, moved eccentrically. This can, for example, be a movement similar to that of a vibrating plate. If a tool 20 with a conventional oscillation drive 10c is used without additional actuators, similar machining results can in principle be achieved with such a system 73 as described above.

Claims

[1] Oscillatingly driven machine tool with a housing (12) in which a motor (26), a tool spindle (18) with a tool holder (31) for fastening a tool (20), and an oscillation drive (36) are accommodated, wherein the oscillation drive (36) is driven by the motor (26) and is coupled to the tool spindle (18) for the rotationally oscillating drive about its longitudinal axis (19), and with at least one controllable actuator (44, 46, 48, 50) in order to superimpose at least one movement component on the rotational oscillation movement of the tool spindle. [2] Machine tool according to claim 1, wherein the at least one controllable actuator (44-50) is coupled at least to the tool spindle (18) or the oscillation drive (36). [3] Machine tool according to claim 2, wherein the at least one actuator (44-50) acts in the housing (12) and on the tool spindle (18), preferably in the region of a bearing (32, 34) of the tool spindle (18). [4] Machine tool according to claim 2 or 3, wherein the at least one actuator (44-50) acts on the tool spindle (18) in such a way that the latter executes a movement with at least one movement component which lies outside a radial plane spanned by the longitudinal axis (19) of the tool spindle (18). [5] Machine tool according to one of the preceding claims, in which a plurality of actuators (44-50) are provided which are arranged such that at least one movement component is to be superimposed on the tool spindle (18) in a radial plane spanned by the longitudinal axis (19) of the tool spindle (18). [6] Machine tool according to one of the preceding claims, in which a plurality of actuators (44-50) are provided, which are arranged such that a plurality of movement components are to be superimposed on the tool spindle (18) in a radial plane spanned by the longitudinal axis (19) of the tool spindle (18). [7] Machine tool according to one of the preceding claims, in which at least one actuator (44-50) is arranged on the tool spindle (18) and in the housing (12) in such a way that a movement component in the axial direction is superimposed on the tool spindle (18). [8] Machine tool according to claim 1, comprising at least one inertial mass (54) on which the at least one actuator (44) acts between the housing (12) and the inertial mass (54). [9] Machine tool according to claim 8, wherein the inertial mass (54) is resiliently suspended in the housing (12), preferably by means of a plurality of spring elements (58, 59, 60, 61). [10] Machine tool according to claim 8 or 9, wherein the at least one actuator (44) acts on the inertial mass (54) in such a way that the latter is movable in a radial plane spanned by the longitudinal axis (19) of the tool spindle (18). [11] Machine tool according to one of the preceding claims, wherein the tool (20, 20a) has an actuator. [12] Machine tool according to one of the preceding claims, with a coupling element (63) which can be fastened on the tool spindle (18) by means of a first receptacle (64), wherein an actuator (44) is received on the coupling element (63), and wherein the coupling element (63) has a second receptacle (68) for the releasable fastening of a working element (70). [13] Machine tool according to claim 12, wherein the coupling element (63) has a first region (64) on which the first receptacle (65) is formed, and a second region (67) on which the second receptacle (68) is formed, and wherein the at least one actuator (44) is arranged between the two regions (64, 67). [14] Machine tool according to claim 13, wherein the two regions (64, 67) are connected to one another by at least one elastic element (66). [15] Machine tool according to one of claims 11 to 13, wherein an interface (71) for connection to the machine tool (10b) is provided on the tool (20a) or on the coupling element (63). [16] Machine tool according to one of the preceding claims, in which the tool (20, 20a) is designed as a sawing tool, in particular for sawing brittle workpieces, such as ceramics, stone, glass, plaster, fiber composite materials. [17] Machine tool according to one of the preceding claims, wherein the at least one actuator (44-50) comprises a piezo element, a nanotubular element, an electrodynamic element or a fluid element. [18] Machine tool according to one of the preceding claims, comprising a controller (42) coupled to the at least one actuator (44-50) in order to periodically excite the at least one actuator (44-50). [19] Machine tool according to claim 18, wherein the at least one actuator (44-50) can be excited with an excitation frequency which is greater than an oscillation frequency of the oscillation drive, preferably with a variable excitation frequency. [20] Machine tool according to one of the preceding claims, in which the at least one actuator (44-50) can be excited with a sinusoidal or rectangular excitation signal and / or the shape of the excitation signal is adjustable. [21] Machine tool according to one of the preceding claims, with an actuator (23) for switching the at least one actuator on and off and preferably an actuator for adjusting the frequency, the amplitude and / or the shape of the excitation signal. [22] Tool with an actuator (44) for applying an excitation signal to the tool (20a) in at least one direction, wherein the actuator (44) is coupled to an electrical interface (71) which is designed for coupling to a machine tool (10b) according to claim 1 with an oscillation drive (36) for the rotationally oscillating drive of a tool spindle (18), and with a receptacle (65) for fastening the tool (20a) to the tool spindle (18). [23] Coupling element with an electrical interface (71) and a receptacle (65) for connection to a tool spindle (18), a rotary oscillating driven machine tool (10b) according to claim 1 and with a tool receptacle (68) for releasably fastening a working element (70) to the coupling element (63), wherein at least one actuator (44) is provided between the receptacle (65) and the tool receptacle (68), which is connected to the electrical interface (71), and wherein the tool receptacle (68) is preferably connected to the receptacle (65) via at least one elastic element (66). [24] System with an oscillatingly driven machine tool (10) according to claim 1 with a housing (12) in which a motor (26), a tool spindle (18) with a tool holder (31) for fastening a tool (20), and an oscillation drive (36) are accommodated, wherein the oscillation drive (36) is driven by the motor (26) and is coupled to the tool spindle (18) for the rotationally oscillating drive about its longitudinal axis (19), and with an external workpiece carrier (76) for receiving a workpiece (78), which has a second oscillation drive (82).

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