DE102013105562B4 - Machine component, vibratory device, system and method for adjusting the natural frequency of an oscillatable device - Google Patents

Abstract

Machine component (3, 3 ', 3 "), in particular a machine tool component, for an oscillatable device, in particular for a machine tool, having at least one cavity (7) designed to receive a recoverable mass (6), characterized in that the at least one cavity (7) comprises one or more ground connections (9) for variably feeding and discharging the variable mass (6), which is variable to change the natural frequency of the oscillatable device, via at least one mass conveying device (15), which is designed to supply fluid from a mass memory (5 ) into and / or out of the at least one cavity (7) of the machine component (3, 3 ', 3 ") by means of a level control system for controlling the filling and emptying of the at least one cavity (7) by measuring the amplitude of vibration of the oscillatory device and comparing the oscillation amplitude with a limit such that the schw ingfähigem device is no longer stimulated at constant process boundary conditions.

Description

The invention relates to a machine component for a vibratory device according to the preamble of claim 1, a system according to claim 9 and a method according to the preamble of claim 17, in particular for a machine tool or a machine tool component.

$$f=\frac{\omega }{2\pi }$$

The technical problems associated with vibratory devices are well known in the art. Such vibratory devices / systems, such as machine tools, are caused to oscillate by the operation of the system, that is, for example, by a machining process of a machine tool. The relationship between the natural frequency f of the oscillatable device and its mass m can be simplified by the following relationships: $$\omega =\sqrt{\frac{c}{m}}$$

$$f=\frac{\omega }{2\pi }$$

The natural frequency f thus depends on the stiffness c of the application and the mass m of the oscillatable device or of the oscillatable component. An increase in the stiffness c consequently increases the natural frequency and an increase in the mass m reduces the natural frequency of the oscillatable device.

The natural frequencies of a machine tool and its components can be excited resonantly, in particular in a processing mode with an interrupted step, for example when milling. The resonant excitation occurs as soon as the machining frequencies are in the range of the natural frequencies. If the machining frequency is close to the natural frequency, the oscillatable system, in particular a machine tool or its components, begins to oscillate. This can lead to a high component load and a concomitant wear of these and surrounding components. In addition, resonant vibrations of the system result in shape mismatch and large surface roughness of the workpiece (e.g., chattering and chattering marks). Mold fidelity or surface roughness is particularly undesirable in visible parts, such as housings, pressure rollers, parts of tools and molds, and unacceptable in parts where high dimensional accuracy is required. Both the form-fidelity and the high surface roughness lead to unusable workpieces and thus to rejects, which in turn entails high unit costs. The vibration behavior of a machine tool is also influenced by workpieces of different weights and workpieces which become lighter as a result of the machining. In particular with a high machining volume, the vibration behavior of the machine tool is thus influenced, since the mass of the oscillatable system is reduced by the workpiece becoming lighter (the mass of workpiece / workpiece carriage drops while the rigidity of the machine tool remains the same). In addition to the lighter workpieces, the vibration behavior is additionally dependent on the positions of the components: The rigidity c of a machine tool depends on how long the lever arms are to the force application points. For example, the stiffness c of a ball screw directly depends on the length from the motor to the slide. In a carriage driven by a ball screw, the rigidity in the feed direction and, consequently, its vibration behavior are position-dependent.

When designing and developing a machine tool, therefore, its vibration engineering design must be taken into special account. Due to changing workpieces and thus workpiece masses and machining processes, the design target is always associated with great uncertainty, since neither machining frequencies nor natural frequencies of the machine can be clearly determined in advance. A process for the development and commissioning of a machine tool usually runs so that first the machine tool is constructed. Then the machine tool is simulated and the design optimized. Subsequently, the machine tool is set up at the manufacturer and the machine tool is put into operation at the customer. If appropriate, the vibration behavior of the machine tool is then adapted on the basis of customer requirements and the processing processes taking place at the customer.

In the past, many attempts have been made to avoid the problems of vibratory systems. However, the aforementioned problems do not only occur in machine tools as described above, but can also relate to any type of oscillatory system, in particular wind turbines of wind turbines or quasi-stationary motors, for example in locomotives, ships, submarines and in other units.

One way to adjust the vibration behavior of a vibratory device is the change of its mass by a suitable choice of material. The 1 shows a graph different vibration amplitude curves for different materials of components of a machine tool. Components made of cast iron or steel are compared with components made of a lightweight construction material such as carbon fiber plastic (CFRP), whereby the components are excited at oscillation frequencies in the region of the natural frequency. The 1 makes it clear that through the use of such new materials, such as carbon fiber reinforced plastic, the natural frequency can be shifted by the lower mass towards higher frequencies while damping the vibration amplitude. However, the application of these lighter materials does not exclude that process-related excitation frequencies can also be in the range of the natural frequency of these "lightweight components". Their application is therefore limited to cases in which the operating frequencies of a vibratory device are significantly different from the natural frequency of the "lightweight components". Through the use of lightweight materials with a high specific rigidity, the mass of the components of an oscillatable device such as a machine tool can be reduced overall. The passive or static frequency shift through the use of new materials, however, shows only a limited potential to solve the problem described above satisfactorily.

In order to avoid resonant oscillations, solution approaches are also known from the state of the art, which relate to the adaptation of the machining process by reducing the feed and the machining depth and the variation of the machining speed or speed. The common goal of these approaches is to adapt the machining frequency of a machine tool so that it does not lie in the range of the natural frequency of the machine tool. That's how it shows DE 10 2012 210 118 A1 For example, a vibration determination method and a vibration determination device, which determines by means of a sensor and a corresponding method, the vibrations in a machine tool, then to make a corresponding adjustment of the machining process. Such methods have the disadvantage that the maximum cutting performance is reduced by the adaptation of the machining process, which in turn results in higher unit costs. Particularly noteworthy is that when a workpiece is machined near a natural frequency, either the chip width, depth or speed must be reduced. In both cases, the machine is not operated in the optimal process. This either has the consequence that the chip width, depth (penetration of the milling cutter into the workpiece) is reduced or the feed is not ideal. This leads to a lower cutting performance and can also lead to an unfavorable surface condition.

Another known from the prior art solution for vibration damping of machine tools is the vibration engineering adjustment of the machines, wherein auxiliary mass damper, friction damper and increasing the mass of individual moving components come through the exchange of complete assemblies used. For example, shows the DE 10 2010 062 250 A1 a rotor with a vibration damper, which intends a vibration damping using an auxiliary mass damper on the rotating shaft. Such solutions reduce the amplitude of vibration of the vibratable device by taking energy from the oscillatory system. In this case, the vibration is damped, but the cause of the problem, namely the operation of the oscillatory device in the vicinity of the natural frequency, not eliminated. Furthermore, these measures require a high constructive and therefore time and financial expense.

From the DE 10 2006 031 145 A1 a profile beam for loads is known, which has a hollow element which is to be acted upon pneumatically and / or hydraulically with a fluid and thereby stiffened, deformed and / or used for vibration compensation.

The DE 41 04 717 A1 shows and describes a vibration-damped and / or braked sliding bearing straight guide unit, in which a guide rail is provided with a longitudinally displaceably arranged on this slide. Between rail and slide an elastic member is provided, which tightly encloses a filling under pressure in a cavity. Via a control valve, the pressure of the filling in the cavity can be changed.

In the DE 10 2007 015 800 A1 a guide carriage for linear guides is disclosed. Stiffness or prestressing and, in addition, the damping properties of the construction should also be changeable via a fluid or plastic medium that can be filled into a cavity, wherein the pressure of the medium should be able to be influenced hydraulically and / or electrically / electronically.

The US 4,773,770 A discloses another solution for a linear guide device with a pressure vessel containing a liquid poster over which the sliding pressure force can be influenced.

Finally, the deals DE 100 46 868 A1 with fillable with liquids and / or granular solids cavities of assemblies of Machine tools. A change in the vibration behavior during operation of the machine tool is not provided in this solution.

The object of the present invention is therefore to provide a machine component and an oscillatable device and a corresponding method, which enable the automatic variation of the natural frequency of an oscillatable device in dependence on current process boundary conditions such that the natural frequency is not close to the operating frequency of the oscillatory Device is located and consequently resonant vibrations of the system are avoided.

To solve the above object, a machine component with the features of claim 1 is proposed. The machine component is, in particular, a machine tool component for an oscillatable device, which may be designed, for example, as a machine tool. The machine component has at least one cavity, which is designed to receive a variable mass that can be conveyed.

For filling and emptying of the at least one cavity, or in other words, for supplying and discharging the variable mass that can be conveyed, one or more ground connections are provided, which open into the at least one cavity. In addition, it can be provided that a plurality of chamber-like cavities are in fluid communication with one another, so that a mass material filled into a cavity can be distributed uniformly over the other cavities.

An essential point of the invention is therefore that a variable mass that can be conveyed, i. a "mass material", as needed in a machine component insertable and can be removed from this again. In concrete terms, this means that the mass of the oscillatable device for varying the natural frequency can be changed as a function of the process boundary conditions. The invention thus enables the dynamic and automatic adjustment of the natural frequency of a vibratory device, such as a machine tool, depending on the present machining / operating frequencies, resulting from the operation of the oscillatory device, for example, during the machining of a workpiece. A suitable control loop with sensors and actuators can thereby ensure the automated supply and removal of the variable mass that can be conveyed to the machine component. The adaptation of the natural frequency is carried out by the variable mass, which is added or subtracted for detuning into the components of the oscillatory device. By adding or subtracting mass m, the natural frequency f is shifted with constant stiffness c (see equations (1) and (2)). In general, the natural frequency can thus be changed in both directions. If a filling of the at least one cavity is provided, the natural frequency can be increased by pumping off.

For level control of the variable mass, the system according to the invention, which consists of at least one cavity, further preferably a control system, which is used for automatically controlling the filling and emptying of the at least one cavity. The control system preferably has a filling device, in particular one or more actuators, such as valves or the like, and sensors. By means of the actuators and sensors, the fill level of the at least one cavity can be detected on the one hand, and corresponding measures for filling or emptying the cavity can be made on the other hand. Furthermore, it is possible with the aid of sensors to detect the oscillation amplitude of the oscillatable device and in the case of a high oscillation amplitude, i. in the case of resonance, to effect the supply or removal of mass material into / from the at least one cavity. The supply or removal of mass material takes place until the oscillation amplitude is again in an acceptable range. It is particularly advantageous if the actuators and sensors are integrated in the machine component. Incidentally, the control system may be part of the control integrated in the machine component or in the oscillatable device. The control system is preferably designed to regulate the filling and emptying of the at least one cavity in the at least one machine component with a variable mass that can be conveyed in such a way that the natural frequency of the oscillatable device is shifted in such a way that it is no longer excited under the same process boundary conditions. If the process boundary conditions change, it may be necessary to carry out a renewed control process, which in turn requires the supply or removal of mass material into / from the at least one cavity.

A machine component according to the present invention may not only be a machine tool component of a machine tool. It is also conceivable that the machine component is parts, in particular a rotor blade, a wind turbine or parts of a quasi-stationary engine, as used for example in locomotives, ships, submarines or other units. In principle, the invention can be applied to any oscillatable device.

As a preferred application example, the present invention will be described with reference to a machine tool component as part of a machine tool. It should be emphasized at this point that a "variable mass that can be conveyed" is understood, in particular, to mean a mass which can be conveyed from a suitable reservoir by means of a conveying device via corresponding lines into the at least one cavity and is in particular "pumpable". It is thus understood in particular no weights or additional masses that are permanently installed or can be manually attached to the machine component. It is crucial that the mass material according to the present invention can be transported fully automatically by means of appropriate conveyors.

The variable mass that can be conveyed may be a fluid, for example water, oil or gel. However, variable masses could also be used for transportable particles, such as sand or dust. Furthermore, it is conceivable to use an electrorheological or magnetorheological fluid as a variable mass that can be conveyed. In this case, the liquid can be solidified by an applied voltage in an advantageous manner to avoid "sloshing" of the liquid in the cavity. The cavity is preferably integrated in the machine component. However, it is also conceivable in principle to connect the cavity in the form of an additional mass-receiving space or mass storage element with the machine element.

Particularly preferred is a machine component which identifies several, in particular adjacent, chamber or honeycomb-like cavities. By the chamber or honeycomb construction can be in a particularly simple manner with the variable mass to be filled cavities, for example by means of hollow profiles produce. This is especially true when the machine components are made of a lightweight material, in particular of a fiber-reinforced plastic, such as glass fiber or carbon fiber reinforced plastic. Conversely, the design of the machine component made of a light metal is also conceivable. Due to the lighter design of the machine component, the natural frequency of the oscillatable device is thus initially shifted upward, while the filling of the at least one cavity with the variable mass that can be conveyed again reduces the natural frequency on the basis of equation (1) above. Depending on the degree of filling of the cavity, a dynamic adaptation of the natural frequency of the machine component is possible in this way, which is produced by the variation of the mass of the machine component. Due to the variable mass, which is selectively conveyed in a desired amount in the cavity, not only the natural frequency can be changed, but at the same time the damping of the oscillation amplitude of the oscillatory device is effected. The amount of mass conveyed into the cavity must be adapted for this purpose in such a way that the natural frequency of the machine component is no longer in resonance with the respective operating frequency. In principle, it is also conceivable to design the machine component from a plurality of different materials in the form of a "multi-material design".

Alternatively, multiple chambers or cavities may be separate from each other, i. not in fluid communication with each other. In this case, each cavity is assigned at least one ground terminal. Preferably, the feedable mass is introduced into the at least one cavity via this one ground connection and transported out of this again. However, it is also conceivable that in each case a ground connection for supplying the variable conveyable mass and a further ground connection for removing the mass from the cavity are provided.

As indicated above, the machine component may be a movable or immovable component of a machine tool. For example, it can be a tool carriage, a headstock, spindle receptacle, spindle slide, frame, bed, stand or a clamping device. Depending on the field of application and different vibratory devices, the machine components may vary accordingly.

The machine tool can be, for example, so-called. Cutting machine tools, such as milling machines, lathes, drills, grinding machines, Hohnmaschinen, woodworking machines, which can also be part of a machining center or a production line. A machine tool according to the subject matter of the invention should have at least one machine component.

As already indicated above, however, the oscillatable device can in principle also be assigned to other fields of use. For example, it may be a wind turbine or the like capable of oscillating.

To achieve the above object, a system with a machine component for a vibratory device with the features of claim 9 is further proposed. The system comprises at least one mass storage, which has at least one fluid line with the at least one cavity of the Machine component is connected. The variable mass variable material stored in the at least one mass storage device may be a fluid such as water, oil or an electro / magnetorheological fluid. On the other hand, the mass storage may also include particles such as sand, dust or the like mass particles that can be conveyed. To promote the variable mass, at least one mass conveying device is provided, which can be, for example, a fluid conveying device, such as a pump or the like. However, it is also conceivable to convey the variable mass by means of compressed air, a vacuum device and / or a membrane device in order to fill the at least one cavity with the variable mass or to remove it from it. The membrane device may be, for example, a type of balloon, which is arranged in the interior of the cavity and can accommodate the variable mass that can be conveyed.

Furthermore, it can be provided that at least two mass storage devices are provided and in particular permanently installed, each of which contains a different mass, in particular fluids such as water and oil, for realizing a multi-fluid filling of the at least one cavity.

To achieve the above object, a method with the features of claim 17 is also proposed. The method is used to adapt the natural frequency of a vibratory device, in particular a machine tool, and is characterized by the filling of at least one cavity of a machine component with a variable mass to be conveyed to change the natural frequency of the oscillatory device such that they no longer at constant process boundary conditions of the oscillatory device is stimulated. Before filling, it is preferable to measure the oscillation amplitude of the oscillatable device and to compare this oscillation amplitude with a limit value. If the limit is exceeded, then preferably the variation of the amount of variable recoverable mass in the at least one cavity. Preferably, in this case, so much recoverable mass is supplied until the natural frequency of the oscillatable device is no longer in the range of the operating frequency, but below it. The limit values can in particular be obtained from an integrated into the oscillatable device or even from an external database or cloud. This preferably comprises different limit values for different oscillatable devices, in particular machine tools of different manufacturers, and / or for different process boundary conditions of the same.

In principle, it is also conceivable to perform a filling and / or emptying of the cavity or cavities before the start of processing (static) by simulation of the machine and / or by means of the database or the cloud. Furthermore, a control of the levels by the analysis of an NC program in the machine control, in particular by a predictive calculation and filling / emptying, be performed. A simulation of the machining process can take place in and outside the machine control. Corresponding extensions of the NC program can be provided for performing corresponding functions. In addition, a control of the levels during the process by means of suitable sensors can be made, which allow a so-called "chatter detection".

The present invention thus makes it possible to realize a fully automated dynamic adjustment of the natural frequency of an oscillatable device with constant rigidity for any process boundary conditions. In this case, the invention makes possible an active detuning of the vibration behavior of the oscillatable device by means of an active, rapid addition and subtraction of mass by a conveyable fluid or similar mass. Furthermore, costly vibration technology adjustments due to significant structural influences in the machine structure are eliminated. Above all, however, a constant variable adaptation of the vibration behavior of the oscillatable device, such as a machine tool, to changing processes, workpieces and workpiece masses and positions of the components can take place.

Moreover, the present invention not only combats the symptoms, but also actively and variably addresses the problem described in the introduction by deliberately detuning the natural frequency of the oscillatable device. In addition, an increase in the cutting power in the field of machine tools and an increase in component quality is achieved, which in turn leads to higher accuracy and surface quality. The invention is also associated with a small financial and time required by the rapid commissioning. Above all, however, a constant variable adaptation of the vibration behavior of the oscillatable device, such as a machine tool, to changing processes and workpieces as well as workpiece masses can take place.

Further features of the invention will become apparent from the dependent claims.

• 1 ein schematisches Schaubild der Variation der Schwingungsamplitude beim Einsatz von verschiedenen Materialien einer Maschinenkomponente;
• 2 ein System zur Anpassung der Eigenfrequenz einer Werkzeugmaschine gemäß einer Ausführungsform der Erfindung;
• 3 eine schematische Darstellung einer Werkzeugmaschine mit typischen schwingfähigen Maschinenkomponenten;
• 4 eine perspektivische Darstellung einer beispielhaften Maschinenkomponente gemäß der Erfindung, und
• 5 eine perspektivische Darstellung einer weiteren beispielhaften Maschinenkomponente gemäß der vorliegenden Erfindung.

The invention will be explained in more detail below with reference to the drawing. Show it:

• 1 a schematic diagram of the variation of the vibration amplitude when using different materials of a machine component;
• 2 a system for adjusting the natural frequency of a machine tool according to an embodiment of the invention;
• 3 a schematic representation of a machine tool with typical oscillatory machine components;
• 4 a perspective view of an exemplary machine component according to the invention, and
• 5 a perspective view of another exemplary machine component according to the present invention.

The 2 shows a schematic representation of a system according to the invention 1 with a machine component 3 and a mass storage 5 containing a fluid, particle or the like variable mass that can be conveyed 6 may contain. At the machine component 3 this is purely an example of a tool carriage of a machine tool, the plurality of chamber-like juxtaposed cavities 7 having.

The tool carriage is preferably made of a carbon fiber reinforced material and may for example comprise a plurality of interconnected hollow profiles. In order to complete the hollow profiles fluid-tight or mass density, is in the 2 Not shown closure plate or the like closure means provided.

The machine component has one or more ground connections 9 of which in the 2 is shown schematically one. The ground connection 9 forms a feed opening through which the machine component 3 and the cavities contained therein 7 over a line 11 with the mass storage 5 connected is. The feed opening may be introduced in the form of a through hole in the closure plate or directly in the main body of the machine component 3. The in 2 shown tool carriage is on a guide system 13 movably mounted. Furthermore, a mass conveyor 15 is provided, which may be formed as a fluid pump. The mass conveyor 15 in the form of the fluid pump is in the present embodiment in the line 11 integrates and promotes the mass in it 6 from the mass storage 5 in the cavities 7 the machine component 3 , The administration 11 , the mass storage 5 , the ground connection 9 and the mass conveyor 15 may be provided with one or more valves for controlling / controlling the supply and removal of mass to / from the cavities 7 be provided. For example, the valves may control the flow direction of the mass as well as the amount and pressure of the supplied mass. The mass storage 5 may be either separate and remote from the vibratable device to power multiple devices or in close proximity to the vibratable device.

It is also conceivable that the mass conveyor 15 and the valves for controlling / controlling the supplied and discharged mass to / from the cavities 7 in the mass storage 5 are integrated.

Depending on the type of variable mass to be delivered 6 may be the type of mass conveyor 15 vary in a suitable way. For example, a promotion of mass 6 from the mass storage 5 in the cavities 7 the machine component 3 and vice versa with the aid of compressed air or vacuum-assisted. Furthermore, a membrane device can be used, which is used for filling and emptying the cavity 7 with the crowd 6 is trained.

During operation of the tool carriage, the latter is moved at a specific speed along the guide system 13 shifted, for example, to edit a workpiece by a cutter or the like tool. As explained above, forms the tool carriage 3 along with the other components in the 2 not shown machine tool an oscillatable device by the displacement of the tool carriage on the guide system 13 is excited to vibrate. This excitation occurs when the machining frequency is in the range of the natural frequency of the machine tool. If the machining frequency is thus close to the natural frequency, the machine tool or its components begins to oscillate, which leads to the disadvantages explained in the introduction.

With the present invention, for example, with the aid of a corresponding control system, the vibration amplitude of the oscillatory device can be detected. For this purpose, the control system preferably has corresponding sensors that can detect the oscillation amplitude. The oscillation amplitude can then be compared with a predetermined limit, which is for example stored in a device integrated in the oscillatable device or in an external database or cloud. If the oscillation amplitude of the oscillatable device exceeds this limit, wear of the components results and the control system, with the aid of a suitable control algorithm, causes the cavities 7 of the machine component to be filled 3 with the recoverable mass 6 from the mass storage 5 , By eligible variable mass 6 increases or decreases the weight of the machine component 3 , which according to the equation (1) leads to a reduction or increase in the natural frequency of the oscillatory device. In other words, the natural frequency is thereby shifted and thus further removed from the processing frequency. The oscillation amplitude of the oscillatory device is damped thereby and reliably prevents wear of the individual components. The oscillation of the oscillatable device is thus actively reduced by varying, in particular by lowering the natural frequency. The filling amount of the variable mass that can be conveyed in the cavity can also be detected by corresponding sensors, counting devices or the like detection devices.

As indicated above, corresponding limit values of the oscillation amplitude, for example for different oscillatable devices, in particular for different machine tools, can be stored in a database. This database can be permanently integrated into the oscillatable device and stored there, in particular in a memory. However, it is also conceivable that the limit values are stored in a global database, which can be accessed by a user of the oscillatable device. The database can be maintained by manufacturers of various vibratory facilities. The limit values are preferably not only stored for various oscillatable devices and in particular machine tools, but preferably different limit values are stored for different machining processes and operating parameters of the oscillatable device, which can be used by the control system according to the invention. For example, various limit values for different tools, workpieces, quantities, cutting depths, etc. may be provided. It is also conceivable that the control system according to the present invention calculates the necessary inflatable or dischargeable mass with the aid of a control / regulating algorithm for this purpose, the set operating parameters, such as feed, depth, speed, mass and structure, etc., the oscillatory Device considered. The system could be further configured to learn from processes and adjust the control algorithm appropriately after each process run. The system is then essentially independent of an external database or manufacturer's information on limit values.

The 3 shows a schematic perspective of the representation of an exemplary machine tool with various movable and non-moving components. Thus, the machine tool comprises a bed or frame 17 , a stand 19 , a spindle slide 21 , a spindle 23 , a Y-carriage 25 and an X-carriage 27. All of these machine components 17 to 27 can have at least one cavity 7 (please refer 2 ), by means of appropriate ground connections 9 with a mass storage 5 for supplying a recoverable variable mass 6 connected is.

The 3 makes it clear that not only one but several machine components of a vibratory device can simultaneously have corresponding cavities for receiving a variable mass that can be conveyed. Transferred to a wind turbine, this means that, for example, one or more of the rotor blades can have corresponding cavities for receiving a variable mass which can be conveyed and thus for adapting the natural frequency of the windmill. In the field of machine tools, for example, a frame and an X-slide could each have at least one cavity for receiving a variable conveyable mass. Overall, the present invention can be used for all components of a machine tool, which have an influence on the vibration behavior of the machine.

The 4 shows a perspective view of another exemplary machine component 3. ' comprising a total of four interconnected hollow profiles 29 made of a lightweight construction material, such as a fiber composite plastic. The open ends of the hollow sections 29 are with a closure plate 31 provided to seal the cavity mass-tight or fluid-tight. At least one of the closure plates 31 has openings 33 for feeding the variable mass that can be conveyed into the hollow profiles 29 on. With the hollow sections 29 is a span 35 connected for a workpiece, which together with the hollow profiles as a support beam by means of a guide system 37 is slidably mounted. The displacement of the hollow sections 29 along the guidance system 37 takes place with the help of a ball screw 39 ,

As to the tool carriage according to 2 has already been explained, it can also with a displacement of the hollow sections 29 on the span 35 include a workpiece to be machined to vibrate when the operating frequency of the machine component 3. ' is in the range of the natural frequency of the oscillatory device. As soon as a corresponding increase in the oscillation amplitude is detected by suitable sensors, the variable mass that can be conveyed becomes the cavities of the hollow sections 29 over the openings 33 in the closure plate 31 introduced, reducing the mass of the hollow sections 29 is increased. At the same time thereby the natural frequency of the oscillatable device is lowered, so that therefore the operating frequency of the machine component 3. ' and their natural frequency are further apart. The Vibration amplitude is thereby reduced and a load on the components avoided.

Finally, the shows 5 Yet another embodiment of a machine component 3 ' , which also several juxtaposed hollow sections 29 and a clamping field arranged thereon 35 for fixing a workpiece to be machined. About appropriate ground connections can be a recoverable mass, such as a fluid such as water or oil in the hollow sections 29 to increase the mass of the machine component 3 ' fill if necessary.

The hollow profiles can be designed differently depending on requirements. Conceivable, for example, hollow profiles with a rectangular or round cross-section, which may have different diameters or dimensions. However, the cavity can also be introduced in the form of a cutout or the like in a machine component. This cavity can be closed with a suitable closure element, which in particular has the feed opening (ground connection). The shape and size (dimensions and volume) of the at least one cavity is totally dependent on the type of machine component and its weight, as well as the weight of the oscillatable device. The volume of the cavity and thus its capacity may also vary depending on the type and weight of the conveyable mass used. Depending on the type of conveying mass used (eg in the case of fluids), it is possible to arrange internals on the hollow profiles or in the cavities, quasi as separating elements (webs, labyrinths and the like), with which, with only partial filling of the hollow space (s), movements of the Fluids or sloshing can be largely excluded. Particularly advantageous may be the use of electro- / magneto-rheological fluids which can be solidified by the application of an electrical voltage.

Overall, the present invention provides an advantageous machine component of a vibratory device and an advantageous method for adjusting the natural frequency of a vibratory device that can vary the natural frequency of the machine component by the targeted and controlled introduction of a variable mass conveyable into a cavity of a machine component. As a result, the oscillation amplitude is reduced and the resonant excitation of the machine component is avoided while the process boundary conditions remain the same. If the process boundary conditions change, the operating frequency may change and, consequently, the natural frequency must be adapted again for changed process conditions, ie the mass is changed by the targeted feeding or removal of a fluid or the like that can be conveyed.

Corresponding actuators or sensors for implementing the control system can be arranged directly in the machine component (not shown in the figures). The control system thus regulates the operation of mass transfer devices, such as fluid delivery pumps or the like, for varying the mass in the cavity of the respective machine component. The fluid delivery device thus interacts with the control system.

The present invention thus provides an advantageous bearing chamber system with a variable fluid filling for optimum adjustment of the natural frequency. The internal damping of the components is also increased by the fluid damping. The component mass is optimized by the application of lightweight design concepts such as material, shape, manufacturing and conceptual lightweight construction and multi-material design. Unlike conventional systems, the overall mass of the machine component does not increase with the present invention due to fluid loading. The level control can be done by database-based approaches or a local control on the machine tool, such as with the aid of a control loop, consisting of sensor and actuator. The pumps or valves can be arranged centrally or remotely. Furthermore, the filling / suction of the variable conveyable mass by compressed air or vacuum and a membrane system for expressing the mass material from the corresponding cavity or cavities can be carried out. Also conceivable is a multi-fluid filling of immiscible liquids (dispersion) with the aim of increasing the boundary layer damping (for example water and oil in a cavity). In the lines which connect the mass storage with the cavities, it is preferably hoses that can transport a suitable amount of mass, in particular fluid, from the mass storage to the cavity. In this way, the filling and emptying of the cavity or the cavities can go very fast.

LIST OF REFERENCE NUMBERS

1

system

3, 3 ', 3 "

machine components

5

mass storage

6

Dimensions

7

cavities

9

ground terminals

11

management

13

guidance system

15

Mass conveyor

17

Bed / frame

19

stand

21

spindle slide

23

spindle

25

Y carriage

27

X slide

29

hollow profile

31

closing plate

33

opening

35

span

37

guidance system

39

Ball Screw

Claims (23)

Machine component (3, 3 ', 3 "), in particular a machine tool component, for an oscillatable device, in particular for a machine tool, having at least one cavity (7) designed to receive a recoverable mass (6), characterized in that the at least one cavity (7) comprises one or more ground connections (9) for variably feeding and discharging the variable mass (6), which is variable to change the natural frequency of the oscillatable device, via at least one mass conveying device (15), which is designed to supply fluid from a mass memory (5 ) into and / or out of the at least one cavity (7) of the machine component (3, 3 ', 3 ") by means of a level control system for controlling the filling and emptying of the at least one cavity (7) by measuring the amplitude of vibration of the oscillatory device and comparing the oscillation amplitude with a limit such that the sch wingable device is no longer excited at constant process boundary conditions. Machine component after Claim 1 , characterized in that it comprises a plurality of, in particular contiguous, chamber or honeycomb-like cavities (7). Machine component after Claim 1 or 2 , characterized in that it is at least partially made of a lightweight construction material, in particular of a fiber-reinforced plastic, preferably of glass or carbon fiber reinforced plastic, or of a light metal. Machine component according to one of the preceding claims, characterized in that it comprises a plurality of different materials. Machine component according to one of the preceding claims, characterized in that a plurality of chamber-like cavities (7) are in fluid communication with each other. Machine component according to one of the preceding claims, characterized in that it is movable or immovable parts of a machine tool, in particular a tool slide (25, 27), headstock, spindle receptacle (23), spindle slide (21), frame, bed (17), Stand (19) or is a clamping device. Machine component according to one of the preceding claims, characterized in that the at least one cavity (7) is formed by a hollow profile. Machine component according to one of the preceding claims, characterized in that on or in the at least one cavity (7) internals, in particular separating elements in the form of webs, labyrinths o. The like. Are arranged to only partially fill the / the cavities movements of the variable Largely exclude mass. System (1) with a machine component for an oscillatable device according to one of the preceding claims, characterized in that the system (1) has at least one mass memory (5) which is connected to the at least one cavity (7) via at least one ground line (11). the machine component (3, 3 ', 3 ") is connected and at least one mass conveying device (15), which is adapted to fluid from the mass memory (5) by means of a level control system for regulating the filling and emptying of the at least one cavity ( 7) into and / or out of the at least one cavity (7) of the machine component (3, 3 ', 3 "). System after Claim 9 Characterized in that it is recoverable in the variable mass of a fluid, in particular water or oil, or particles, sand, a gel or an electro- or magneto-rheological fluid. System after Claim 9 , characterized in that the at least one mass conveying device (15) is designed as a centralized or decentralized fluid pump. System after Claim 11 , characterized in that the mass conveying device (15) by means of compressed air, vacuum and / or a membrane device for filling and emptying of the at least one cavity (7) is formed. System according to one of Claims 9 to 12 , characterized in that the control system comprises actuators, in particular valves, and sensors. System after Claim 13 , characterized in that the actuators and sensors in the machine component (3, 3 ', 3 ") are integrated. System according to one of the preceding Claims 13 or 14 , characterized in that the control system is adapted to regulate the filling and emptying of the at least one cavity (7) in the at least one machine component (3, 3 ', 3 ") so that the natural frequency of the oscillatable device is shifted in such a way, that it is no longer excited at constant process boundary conditions. System according to one of the preceding Claims 9 to 15 , characterized in that at least two mass storage (5) are provided, each of which contains a different fluid, in particular water and oil, for realizing a Multifluidbefüllung the at least one cavity (7). Method for adapting the natural frequency of an oscillatable device, in particular a machine tool, with a machine component according to one of Claims 1 to 8th or a system according to one of Claims 9 to 16 characterized by filling at least one cavity (7) of a machine component (3, 3 ', 3 ") with a variable mass that can be conveyed (6) such that the natural frequency of the oscillatable device is controlled by means of a control system such that the filling and emptying of the at least a cavity (7) in the at least one machine component (3, 3 ', 3 ") is to be controlled so that the natural frequency of the oscillatory device is changed such that it is no longer excited at constant process boundary conditions of the oscillatory device. Method according to Claim 17 characterized by measuring the vibration amplitude of the vibratable device and comparing the vibration amplitude with a threshold. Method according to Claim 18 characterized by filling the at least one cavity when the limit is exceeded. Method according to one of Claims 18 or 19 Characterized by obtaining the appropriate threshold from a built in the vibratory device or external database or cloud that different limit values for various oscillatory devices, particularly machine tools, and / or for different process conditions thereof. Method according to one of the preceding Claims 17 to 20 , characterized by filling and / or emptying before the start of processing, in particular by simulation of the machine and / or the database cloud. Method according to one of the preceding Claims 17 to 21 characterized by a control of the levels by the analysis of an NC program in the machine control, in particular by a predictive calculation and filling / emptying. Method according to one of the preceding Claims 17 to 22 , characterized by the control of the levels during the process by means of sensors.

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