Spindle with damping bearing flange

Abstract

In a machine tool (2) with a tool and / or workpiece spindle, chatter vibrations are to be reduced or avoided. For this purpose, the spindle (10, 30) comprises at least one spindle housing (32), a spindle bearing (33, 34), and a bearing flange (35) for receiving the spindle bearing (33, 34) and for securing to the spindle housing (32), wherein the bearing flange (35) has at least one bearing-receiving part (36) for receiving the spindle bearing (33, 34) and a securing part (37) for securing the bearing flange (35) to the spindle housing (32), and the bearing-receiving part (36) and the securing part (37) are elastically interconnected by means of at least one elastically deformable connecting means (38). By virtue of the elastic connection between the bearing-receiving part (36) and the securing part (37), chatter vibrations are reduced or avoided using the spindle (10, 30).

Description

[0001] Description

[0002] Spindle with damping bearing flange

[0003] The invention relates to a spindle, in particular a tool and / or workpiece spindle, comprising at least one spindle housing, one spindle bearing and one bearing flange for receiving the spindle bearing and for fastening to the spindle housing, wherein the bearing flange has at least one bearing receiving part for receiving the spindle bearing and one fastening part for fastening the bearing flange to the spindle housing.

[0004] Furthermore, the invention relates to a bearing flange for a spindle, in particular a tool or workpiece spindle, comprising at least one bearing receiving part for receiving the spindle bearing and a fastening part for fastening the bearing flange to a spindle housing.

[0005] Furthermore, the invention relates to a machine, in particular a machine tool or a robot.

[0006] Furthermore, the invention relates to a digital twin of a spindle, in particular a tool and / or workpiece spindle, comprising at least one spindle housing, one spindle bearing and one bearing flange for receiving the spindle bearing and for fastening to the spindle housing, wherein the bearing flange has at least one bearing receiving part for receiving the spindle bearing and one fastening part for fastening the bearing flange to the spindle housing.

[0007] Many machines use spindles to move or clamp parts. For example, in a machine tool, tools or workpieces are attached to and driven by a tool or workpiece spindle. During machining operations using a machine tool, forces can be so great that damage can occur to the tool or the machine, especially the main spindle, or the tool life can be reduced.

[0008] A spindle, especially a tool spindle or workpiece spindle, is a central component in machine tools such as lathes, milling machines, and drilling machines. Its purpose is to hold and rotate the tool or workpiece in order to machine the workpiece using the tool. A spindle comprises several essential components that work together to enable precise and efficient machining of the workpiece. Common components include:

[0009] - A (spindle) housing.

[0010] Bearings: These hold the spindle shaft in position and reduce friction during rotation. Precision bearings are particularly important because they must withstand high speeds and loads. Rolling bearings, especially ball bearings, are commonly used.

[0011] - Bearing flanges: These are used to attach the bearings to the housing.

[0012] - A spindle shaft: It transmits the power of the motor to the tool and must be manufactured with extreme precision to minimize vibrations and ensure high accuracy.

[0013] - A motor or drive unit: This drives the spindle shaft. There are various types of motors, such as direct drive motors or belt drive systems, which are used depending on the application.

[0014] - Cooling and lubrication systems: These are essential to control heat generation in the spindle and to increase the spindle's service life.

[0015] - A tool or workpiece holder: This is the connecting element between the spindle and the tool or workpiece. It must be very stable and precise to securely fix the tool or workpiece and enable high speeds.

[0016] In the context of machining a workpiece using a machine tool, chatter effects, chatter vibrations, or simply "chatter" refer to unwanted vibrations that occur during the machining process. These vibrations can be caused by various factors and have a significant impact on the quality of the machined workpiece as well as on the service life of the tools and machines.

[0017] There are two main types of rattles:

[0018] Regenerative chatter: This refers to self-excited vibrations caused by the interaction between the tool and the workpiece. When the tool strikes the workpiece, it creates waves on the surface, which are picked up again during the next cut, leading to amplified vibrations. This can result in poor surface quality, increased tool wear, and even damage to the machine.

[0019] Non-regenerative chatter: These vibrations are caused by external influences such as imbalances, bearing defects, or external vibrations. They are not the result of the interaction between the tool and the workpiece but are forced by external factors. Regenerative chatter in milling refers to an undesirable vibration behavior that can occur during the milling process. It is a type of self-excited vibration that arises during cutting due to interactions between the milling tool, the workpiece, and the machine. The causes are usually a combination of the machine's dynamic properties (resonances) and process parameters such as cutting speed, depth of cut, feed rate, and tool geometry. Chatter can lead to reduced milling quality, shortened tool life, and decreased machining efficiency.

[0020] To avoid or reduce chatter effects, cutting parameters are determined iteratively – often with a large number of iteration loops – experimentally for the specific machining operation. Another, more complex method is the systematic creation of so-called chatter maps, in which the dynamic behavior of the machine is experimentally determined to identify stable machining zones. Both measures are very time-consuming and, due to the inherent tool dependency, must be repeated. The goal is to determine the point at which the process becomes unstable or at which it is just barely stable.

[0021] Another way to reduce chatter vibrations (chatter) is to use damping systems such as damping tool holders.

[0022] The object of the present invention is to reduce or avoid chatter in machine tools in a simple, efficient and cost-effective manner.

[0023] This problem is solved by a spindle with the features according to claim 1, i.e. a spindle, in particular a tool and / or workpiece spindle, comprising at least a spindle housing, a spindle bearing and a bearing flange for receiving the spindle bearing and for fastening to the spindle housing, wherein the bearing flange has at least one bearing receiving part for receiving the spindle bearing and a fastening part for fastening the bearing flange to the spindle housing, wherein the bearing receiving part and the fastening part are elastically connected to each other by at least one elastically deformable connecting element.

[0024] The problem is further solved by a bearing flange for a spindle with the features according to claim 13, i.e. a bearing flange for a spindle, in particular a tool or workpiece spindle, comprising at least one bearing receiving part for receiving the spindle bearing and a fastening part for fastening the bearing flange to a spindle housing, wherein the bearing receiving part and the fastening part are elastically connected to each other by at least one elastically deformable connecting element.

[0025] Furthermore, the problem is solved by a machine according to claim 14, i.e. a machine, in particular a machine tool or robot, comprising a spindle according to one of claims 1 to 12.

[0026] Furthermore, the problem is solved by a digital twin for simulating a spindle with the features according to claim 15, i.e., a digital twin for simulating a spindle, in particular a tool and / or workpiece spindle, comprising a digital representation of at least one spindle housing, one spindle bearing, and one bearing flange for receiving the spindle bearing and for fastening it to the spindle housing, wherein the bearing flange has at least one bearing receiving part for receiving the spindle bearing and one fastening part for fastening the bearing flange to the spindle housing, wherein the bearing receiving part and the fastening part are elastically connected to each other by at least one elastically deformable connecting element, and wherein the elastic deformation of the elastically deformable connecting element as a result of an external force acting on the spindle (also simulated) can be simulated by means of the digital twin.

[0027] Previously, spindles for machine tools (tool spindles, workpiece spindles) were designed to be as rigid as possible to achieve the highest possible positioning accuracy of the tool and / or workpiece. In particular, bearing flanges for spindles were designed so that the bearing housing component for the spindle bearing and the mounting component for attaching the bearing flange to the spindle housing were as rigid and robust as possible. Elastic deformation between these two parts of the bearing flange was undesirable and had to be avoided.

[0028] In contrast, the bearing flange according to the invention requires a certain degree of elasticity between the bearing receiving part and the mounting part of the bearing flange. By using a special bearing flange, the elasticity of the spindle is specifically increased or its stiffness reduced in order to counteract chatter vibrations.

[0029] An advantage of the present invention over damping tool holders is that the functionality, i.e., the elasticity or damping effect, is integrated directly into the spindle (specifically the bearing flange), so that a multitude of tool holders for different tools is not required. The spindle according to the invention differs from a conventional spindle in that at least the bearing flange at the front (tool- or workpiece-side) bearing, which is usually designed as a fixed bearing, is not solid and therefore as rigid as previously thought, but exhibits a certain degree of elasticity.According to the invention, this is achieved by the bearing flange having at least one bearing receiving part for receiving the spindle bearing and one fastening part for fastening the bearing flange to the spindle housing, wherein the bearing receiving part and the fastening part are elastically connected to each other by at least one elastically deformable connecting element. Conventional bearing flanges for spindles lack such an elastically deformable connecting element.

[0030] In connection with the invention, a spindle, particularly a tool spindle, has proven to have a significantly higher elasticity of approximately 10% to 30%, preferably 20%, and consequently a significantly lower stiffness of approximately 10% to 30%, preferably 20%, at the spindle nose (tool interface) compared to a conventional spindle. To achieve these values, the bearing flange used in connection with the invention has a stiffness that is 0.1 to 0.25 times lower, preferably 0.2 times, than that of a conventionally used, solid bearing flange.

[0031] To achieve the desired elasticity compared to a conventional bearing flange, there are various options that can be implemented individually or in combination:

[0032] Preferably, the elastic deformability is achieved through the special design, in particular by saving material in the area between the bearing receiving part and the fastening part of the bearing flange, and by making this area correspondingly less massive and therefore less stiff.

[0033] Another possibility lies in the specific shaping of the fastener. Here, too, there are numerous possibilities for achieving the desired effect. In particular, the fastener can, for example, be funnel-shaped or disc-shaped to achieve the desired flexibility. Furthermore, to achieve the desired flexibility, the fastener can also be shaped entirely or partially in a zigzag, wavy, corrugated, spiral, etc. form, so that the elasticity is achieved or increased through the specific shape.

[0034] A preferred embodiment of the invention provides that the elastically deformable connecting element comprises at least one rod and / or strut, in particular a plurality of rods and / or struts, or is designed as a rod and / or strut, in particular as a plurality of rods and / or struts. The elastic properties of the bearing flange, and thus of the spindle itself, can be influenced in various ways, particularly by the number, dimensions, distribution, orientation, or materials used of the rods or struts. The rods or struts are preferably uniformly flat or plate-shaped.

[0035] Besides rods and / or struts, a variety of other design options are possible to achieve the intended deformability or elasticity of the elastically deformable connector. For example, it could also be designed, at least in its essential form, as an arc, funnel, plate, etc.

[0036] To further increase elasticity, the chosen shape of the elastically deformable connecting element can also be zigzag-shaped, wavy or corrugated, spiral-shaped, etc., at least in sections.

[0037] The bearing housing, the fastening element, and the elastically deformable connecting element are preferably formed in one piece and manufactured in a single operation, e.g., by a metal casting or 3D printing process. Ideally, the three parts are made of the same material. These measures each enable simple and cost-effective manufacturing with good mechanical properties.

[0038] Preferably, the rods or struts connecting the bearing receiving part and the fastening part are evenly distributed around the circumference of the bearing flange. In particular, exactly four or multiples of four rods or struts evenly distributed around the circumference of the bearing flange are present, so that the bearing flange can absorb and dampen forces in any radial direction.

[0039] In a preferred embodiment of the invention, the elastically deformable connecting element is inclined with respect to a cross-section at an angle in the range of 30° to 60°, in particular 45°, relative to a spindle axis (spindle longitudinal axis). In particular, in an embodiment of the elastically deformable connecting element in the form of a number of rods and / or struts, the rods or struts are inclined at an angle in the range of 30° to 60°, in particular 45°, relative to the spindle axis. This achieves high elasticity in both the axial and radial directions, and in particular, at least approximately the same elasticity in both directions. The desired elastic deformability can also be achieved, or additionally achieved, by special material properties of the elastically deformable connecting element compared to the bearing support part and the fastening part.For the elastically deformable connecting element, a different material composition, in particular a “softer” material, would be chosen than for the other parts of the bearing flange.

[0040] In one embodiment of the invention, the bearing flange is manufactured using a 3D printing process. This makes it possible to easily produce even complex shapes of the elastically deformable connecting element, e.g., in the form of a number of corrugated or bent struts, as well as different material compositions in different areas.

[0041] In one embodiment of the invention, the bearing flange has at least one cooling channel, and in particular a plurality of cooling channels, for conveying a cooling medium to cool the bearing flange and, in particular, the spindle bearing. This variant can also be advantageously manufactured by means of 3D printing.

[0042] In one embodiment of the invention, the bearing flange, in particular the elastically deformable connecting element, has at least one cavity that can be filled with, or is filled with, a damping material. In addition to its elastic properties, the bearing flange thus also has a damping effect, which further contributes to the suppression of chatter vibrations.

[0043] In order to limit the elastic deformability of the bearing flange according to the invention at least substantially to a certain maximum, a preferred embodiment of the spindle or the bearing flange provides at least one stop element to limit the elastic deformation of the bearing flange.

[0044] Advantageously, a damping element can also be provided between the bearing flange and the stop, which dampens the elastic deformation of the bearing flange. Preferably, the stop element includes the damping element, for example, by forming the stop element and the damping element as a single piece using 3D printing, or the damping element is connected to the stop element, e.g., by bonding.

[0045] Furthermore, elastic deformation allows for a relatively simple and cost-effective determination of the forces acting on the bearing flange. Because the elastic deformation of the bearing flange is at least essentially limited to a specific area of ​​the flange, namely the elastically deformable connecting element, the deformation in this area can be measured particularly well and easily with at least one sensor element.

[0046] In an advantageous embodiment of the invention, the elastically deformable connecting element has at least one sensor element, in particular a strain gauge, for determining an elastic deformation of the elastically deformable connecting element.

[0047] Strain gauges are particularly suitable as sensor elements. These are available on the market in a wide variety of designs and are especially cost-effective. Attaching the strain gauges to the surface of the rods or struts is also very simple, for example by gluing. Integrating sensor elements into the rods or struts, for example by potting, is also possible, but a correspondingly more complex and expensive alternative.

[0048] However, the invention is not limited to the use of strain gauges. In principle, other sensor elements can also be used to determine the strain or compression of the at least one elastic connecting element, e.g. displacement sensors or optical fibers.

[0049] Advantageously, the elastically deformable connecting element is designed such that at least four sensor elements can be arranged on the bearing flange, each offset by 90° with respect to the spindle axis. This arrangement of the sensor elements also allows for accurate determination of the direction in which an external force acts on the bearing flange.

[0050] In one embodiment of the invention, the spindle is designed as a motor spindle, and the bearing flange is thus designed as the bearing shield of the motor spindle. The bearing shield is to be regarded as a special embodiment of a bearing flange according to the invention, which, in addition to the aforementioned functions of a bearing flange, also serves as a cover for the electric motor of the motor spindle. This embodiment is particularly compact, since the spindle shaft is also the motor shaft. The advantages of the invention already mentioned also apply in this application.

[0051] An advantageous feature of a machine according to the invention is that it comprises a spindle according to the invention. The machine according to the invention is preferably designed as a machine tool or robot, and the spindle can be connected to a tool, and the movement of the tool can be controlled such that it performs the intended processing or manufacturing of a workpiece. In a robot according to the invention, the spindle according to the invention is mounted at the front end of the robot arm or manipulator.

[0052] Today, it is common practice to simulate the machining process before actually machining a workpiece with a machine tool. A digital twin of the machine tool is used for this purpose. The more details of the machine are included in the simulation in the form of corresponding digital twins, the better the simulation will be and the more accurately it will match the machine's actual behavior. Therefore, it is advantageous to also provide a digital twin of the spindle and / or bearing flange according to the invention. This allows the properties of the spindle and / or bearing flange to be included in the simulation, making it even more accurate and realistic. In particular, this allows the risk of chatter vibrations to be identified before actual machining and suitable countermeasures to be taken to prevent them.Furthermore, it is possible to optimize the intended spindle or its bearing flange based on the insights gained in the simulation, or to select the spindle best suited for a specific application from several different spindles.

[0053] To create a digital twin of mechanical components of a machine tool, such as the spindle, several common methods and technologies can be employed. These methods make it possible to create an accurate digital replica of the physical components, especially (also) the spindle, in order to perform simulations of the machine tool's function. Here are some of the common approaches:

[0054] CAD models (Computer-Aided Design):

[0055] CAD software is used to create detailed 3D models of the mechanical components. These models include all geometric and structural details necessary to digitally represent the physical component.

[0056] Finite Element Method (FEM):

[0057] The finite element method (FEM) is used to simulate the physical properties and behavior of mechanical components under various operating conditions. FEM analyses help to investigate stresses, deformations, and other mechanical phenomena.

[0058] Computational Fluid Dynamics (CFD): For components where fluid mechanics plays a role, CFD is used to simulate the behavior of liquids and gases. This is particularly important for cooling systems or pneumatic systems in machine tools.

[0059] Sensor integration and data acquisition:

[0060] Sensors are installed on the physical components of the machine tool to collect real-time data. This data is then used to provide the digital twin with current operating conditions and performance metrics.

[0061] Physics-based modeling:

[0062] Physics-based models are developed to simulate the dynamic properties and behavior of mechanical components. These models are based on physical laws and equations that describe the behavior of the components.

[0063] Machine learning and AI:

[0064] Machine learning and AI algorithms are used to learn from large datasets and create precise models of component behavior. These models can be used to predict future conditions and develop preventive maintenance strategies.

[0065] Virtual commissioning:

[0066] Virtual commissioning software makes it possible to test and optimize the digital twin of the machine tool in a virtual environment before the physical machine is put into operation. This helps to identify and correct errors before they occur in the real world.

[0067] Kinematic and dynamic simulation:

[0068] Kinematic and dynamic simulations are performed to analyze the movements and interactions between the mechanical components. These simulations help to improve the performance and efficiency of the machine tool.

[0069] By combining these methods and technologies, engineers and developers can create a comprehensive and accurate digital twin of the machine tool or its components. This digital twin makes it possible to simulate, analyze, and optimize the function of individual machine components or the machine as a whole, ultimately improving the machine's efficiency and reliability. The digital twin can be advantageously used in the design of a spindle according to the invention, for example, by virtually testing in advance how certain design measures, such as the number, arrangement, or dimensions of the bearing flange struts, affect the elasticity of the bearing flange or the spindle.However, the digital twin can also be advantageously used to simulate and test the behavior of a specific spindle according to the invention in the machine, for example during the machining of a workpiece.

[0070] The invention is described and explained in more detail below using exemplary embodiments. These include:

[0071] FIG 1 A machine tool with a tool spindle,

[0072] FIG 2 shows a sectional view of a conventional motor spindle,

[0073] FIG 3 shows a sectional view of a motor spindle according to the invention,

[0074] FIG 4 shows a tilting of the spindle shaft in conjunction with a conventional motor spindle,

[0075] FIG 5 shows a tilting of the spindle shaft in conjunction with a motor spindle according to the invention,

[0076] FIG 6 shows a bearing shield of a motor spindle according to the invention in a spatial view,

[0077] FIG 7 shows a preferred embodiment of a bearing shield according to the invention.

[0078] Figure 1 schematically depicts a machine tool system in the form of a machine tool system 1. The machine tool system 1 comprises a machine tool in the form of a machine tool 2. Furthermore, the machine tool system 1 comprises a numerical control device in the form of a CNC controller 3 connected to the machine tool 2 for controlling the machine tool 2. In addition, the machine tool system 1 comprises an external computing device in the form of a CAD / CAM system 5 connected via a network 4, for example, the Internet.

[0079] The machine tool 2 shown has three position-controlled linear axes X, Y, and Z, wherein a first support element 7 is adjustable in the x-direction, a second support element 8 in the y-direction, and a third support element 9 in the z-direction with respect to a machine coordinate system (MCS) that is fixed relative to the machine tool 2. The first support element 7 is connected to a stationary machine frame 6 via a linear drive adjustable in the x-direction (not shown), the second support element 8 is connected to the first support element 7 via a linear drive adjustable in the y-direction (not shown), and the third support element 9 is connected to the second support element 8 via a linear drive adjustable in the z-direction (not shown).

[0080] The third support element 9 carries a motor spindle 10, which is pivotable about a position-controlled rotary axis B parallel to the Y-axis. The motor spindle 10 in turn has a spindle or motor shaft 11 that is rotatable about a spindle axis (not shown) and whose speed and / or position is controlled. A tool holder 12 with the attached tool 13 is clamped at the front end of this shaft.

[0081] Furthermore, the machine tool 2 includes a position-controlled tool table axis C aligned parallel to the Z-axis, around which a workpiece table 14 can be rotated.

[0082] The tool table 14 is also connected to the stationary machine frame 6 and a workpiece 16 is attached to the tool table 14 by means of the tool holders 15.

[0083] In this embodiment, machine tool 2 has five position-controlled machine axes, enabling relative movement between the tool 13 (a milling cutter in this embodiment) and the workpiece 16. It is therefore a so-called 5-axis machine tool (5-axis machine), although it should be noted that a machine tool can, of course, have more or fewer than five machine axes. For the sake of clarity, the drives for the position-controlled machine axes are not shown in this embodiment.

[0084] The machine tool 2 is connected to the CNC control 3, which determines target values ​​for the machine axes based on a part program and / or manual input to control a relative movement between the tool 13 and the workpiece 16. The CNC control 3 determines the target values ​​primarily based on the part program, in which the movements to be performed by the tool 13 relative to the workpiece 16 are defined in the form of commands or program instructions, usually in the form of G-code.

[0085] Alternatively or additionally, the movement of the tool 13 and / or the workpiece 16 can also be controlled manually by an operator on-site at the machine tool 2 via an operating device with control elements 18 in conjunction with a display device in the form of a screen 17 of the CNC control 3. The control elements 18 include, in particular, pushbuttons or rotary knobs. Advantageously, the screen 17 can also be designed as a touchscreen and thus also as a control element.

[0086] The part program is usually generated in a computing device external to the CNC control, in the exemplary embodiment the CAD / CAM system 5 and a so-called post-processor (not shown) possibly connected downstream of the CAD / CAM system, and is transferred from there, in particular via the network 4, to the CNC control 3.

[0087] In the embodiment shown in FIG. 1, the CNC control 3 and / or the external computing device 5 are configured to first simulate the actual machining of the workpiece 16 using the machine tool 2. For this purpose, digital representations of at least all essential components of the machine tool 2, the tool 13, and the workpiece 16 are stored in the CNC control 3 or the external computing device 5. For the simulation, the CNC control 3 or the external computing device 5 executes, in particular, the same part program that is also executed by the CNC control 3 during actual machining. The simulated machining can be visually displayed on the display 17 of the CNC control 3 and / or a display of the external computing device 5.

[0088] Advantageously, in the embodiment shown in FIG. 1, the tool spindle 10 is designed in the form of a spindle according to the invention, which includes a bearing flange according to the invention (not visible from FIG. 1).

[0089] FIG. 2 shows a sectional view of a conventional motor spindle 20. Particularly visible are a spindle shaft or motor shaft 21, a housing (spindle housing) 22, rolling bearings 23 and 24, and a bearing flange 25 for mounting and fixing the rolling bearings 23 and 24. As can also be seen in the figure, the bearing flange 25 is made of solid material and therefore has high rigidity. Details of the motor that are irrelevant to the invention have been omitted from the figures (especially FIG. 2 and FIG. 3) for the sake of clarity.

[0090] FIG. 3, unlike FIG. 2, shows a sectional view of a motor spindle 30 according to the invention, comprising a spindle shaft or motor shaft 31, a housing 32, and the two rolling bearings 33 and 34. A bearing flange 35 is also visible, which here too serves to fasten and fix the rolling bearings 33 and 34, but differs fundamentally in its construction from the bearing flange 25 shown in FIG. 2. It should also be noted that—unlike what is shown in FIGS. 2 and 3—embodiments with only one bearing, e.g., bearing 33, are also common in this area of ​​the spindle and are covered by the invention.

[0091] The bearing flange 35 also serves to receive the spindle bearings 33, 34 and to attach them to the spindle housing. In contrast to the bearing flange 25, the bearing flange 35 can be divided into at least three functionally distinct areas: a bearing receiving part 36 for receiving the spindle bearings 33, 34, a fastening part 37 for attaching the bearing flange 35 to the spindle housing 32, and an elastically deformable connecting element 38 by which the bearing receiving part 36 and the fastening part 37 are elastically connected to each other.

[0092] In the exemplary embodiment, the elastically deformable connecting element 38 is designed as a number of struts 38, each of which is inclined at an angle of approximately 45° to a spindle axis 39.

[0093] For better illustration, the bearing flange 35 with the bearing receiving part 36, the fastening part 37 and the elastically deformable connecting element in the form of a number of struts 38 are shown again in a spatial view in FIG 4.

[0094] Figures 5 and 6 illustrate a significant advantage of the invention. Figure 5 shows a tilting of the spindle shaft 21, particularly as a result of a large external force F acting on the motor spindle and especially on the spindle shaft 21, in conjunction with a conventional motor spindle. With the standard solid bearing flange 25, an external radial force F causes a relative tilting of the inner ring to the outer ring of the rolling bearing 23 in the force transmission path. This tilting can lead to kinematically unclean operating conditions and to the lifting (unloaded running) of individual rolling elements.

[0095] In contrast, a spindle or bearing flange 35 according to the invention according to FIG. 6 is designed differently. The flexible bearing flange 35 designed according to the invention allows, when a large external force F is applied, the elastically deformable struts 38 cause elastic deformation of the bearing flange 35, in particular a tilting movement of the bearing receiving part 36 relative to the fastening part 37, and thus a following of the outer rings of the rolling bearing 33 in the force flow, which reduces the tilting in the bearing.

[0096] A preferred embodiment of the bearing flange 35 according to the invention is shown in FIG. 7. In such a bearing flange, a stop may be provided, in the embodiment according to FIG. 7 in the form of the projections 40, which restrict the range of elastic deformation or limit it to a maximum possible deformation. Furthermore, as shown in FIG. 7, a damping element 41, e.g., an elastomer or a squeeze film, may be provided in the area of ​​the stop, which has a damping effect, particularly in the area of ​​maximum elastic deformation. The damping element 41, like the stop 40, is preferably annular in shape with the spindle axis as its axis of symmetry.

[0097] Furthermore, cooling channels 42 can be provided in a bearing flange according to the invention, which enable optimized bearing heat dissipation.

[0098] Furthermore, the bearing flange according to the invention preferably comprises, in the area where the greatest deformation occurs in the elastically deformable connecting element, in the exemplary embodiment the strut 38, as a result of an external force, at least one cavity 43 filled with a damping agent, thereby damping the elastic deformation. Powder particles are particularly suitable as damping agents, as they cause damping (particle damping) due to friction.

[0099] The aforementioned special features of the bearing flange according to the invention can be implemented particularly easily and cost-effectively if the bearing flange is manufactured using a 3D printing process. The design of the struts, the cooling channels, the stop elements with the damping ring, and the powder-filled chambers for damping is thus particularly simple and, in particular, possible in a single operation.

[0100] In the embodiment of the invention according to FIG. 7, the elastically deformable connecting element in the form of struts 38 has at least one sensor element, in particular a strain gauge 44, for determining elastic deformation of the struts 38. Advantageously, four strain gauges are attached to the bearing flange 35 at uniform intervals, i.e., offset by approximately 90° with respect to a spindle axis (not shown in FIG. 7), e.g., by gluing. The elastic deformation of the struts 38 can be measured by means of the strain gauges, and thus the force acting on the spindle and its direction can be determined very accurately. The evaluation of the sensor signals to determine the force acting on the spindle can be carried out, for example, in the CNC control 3 (see FIG. 1). Knowledge of the force and its direction can be used in the CNC control 3, for example, to adjust control parameters relating to the machining of the workpiece.The feed rate can be adjusted or optimized. Many other pieces of information can also be derived from the force and its progression over time, such as an indication of a worn tool or the occurrence of chatter vibrations.

[0101] The additional features shown in combination in FIG. 7 (stop elements 40, damping means 41, cooling channels 42, cavities 43 filled with a damping means, strain gauges 44) can also be present individually in a bearing flange according to the invention, i.e. not in combination with further or all of the features shown or in any combination.

[0102] Compared to a standard, solid bearing flange, the use of a spindle according to the invention in a machine tool allows for a significantly higher feed rate (width and depth of cut) of the tools during the milling process, thus increasing milling performance and productivity. Chatter vibrations are shifted to higher feed rates. By selecting conservative milling parameters, the milling process becomes less susceptible to chatter and is therefore more stable overall.

[0103] Advantageously, the CNC control 3 shown in FIG. 1, optionally in conjunction with the external computing device 5, allows the machining of the workpiece 16 using the machine tool 2 to be simulated first. A digital twin of the machine tool 2 is used for this purpose. Therefore, it is also advantageous to provide a digital twin of the spindle 10, 30, or the bearing flange 35 according to the invention (see FIGS. 3 to 7), in which, in particular, the elastic deformation of the elastically deformable connecting element 38 between the bearing receiving part 36 and the fastening part 37 under the influence of a (simulated) external force can also be simulated. This allows the properties of the spindle 10, 30, or the bearing flange 35 to be included in the simulation, making it even more accurate and realistic.

Claims

Patent claims 1. Spindle (10, 30), in particular a tool and / or workpiece spindle, comprising at least a spindle housing (32), a spindle bearing (33, 34) and a bearing flange (35) for receiving the spindle bearing (33, 34) and for fastening it to the spindle housing (32), wherein the bearing flange (35) has at least one bearing receiving part (36) for receiving the spindle bearing (33, 34) and a fastening part (37) for fastening the bearing flange (35) to the spindle housing (32), characterized in that the bearing receiving part (36) and the fastening part (37) are elastically connected to each other by at least one elastically deformable connecting element (38).

2. Spindle (10, 30) according to claim 1, wherein the elastically deformable connecting element (38) comprises at least one rod and / or strut, in particular a plurality of rods and / or struts, or is designed as a rod and / or strut, in particular as a plurality of rods and / or struts.

3. Spindle (10, 30) according to claim 2, wherein the bearing receiving part (36) and the fastening part (37) are connected to each other by several rods and / or struts.

4. Spindle (10, 30) according to one of the preceding claims, wherein the bearing receiving part (36), the fastening part (37) and the elastically deformable connecting element (38) are formed in one piece.

5. Spindle (10, 30) according to one of the preceding claims, wherein the elastically deformable connecting element (38) is inclined by an angle in the range of 30° to 60°, in particular 45°, relative to a spindle axis (39).

6. Spindle (10, 30) according to one of the preceding claims, wherein the bearing flange (35) is manufactured using a 3D printing process.

7. Spindle (10, 30) according to one of the preceding claims, wherein the bearing flange (35) has at least one cooling channel (42) for conveying a cooling medium.

8. Spindle (10, 30) according to one of the preceding claims, wherein the bearing flange (35), in particular the elastically deformable connecting element (38), has at least one cavity (43) which can be filled with a damping element.

9. Spindle (10, 30) according to one of the preceding claims, wherein the bearing flange (35) has at least one stop element (40) for limiting elastic deformation.

10. Spindle (10, 30) according to claim 9, wherein the stop element (40) comprises a damping element or is connected to a damping element (41).

11. Spindle (10, 30) according to one of the preceding claims, wherein the elastically deformable connecting element (38) has at least one sensor element for determining an elastic deformation of the elastically deformable connecting element (38).

12. Spindle (10, 30) according to one of the preceding claims, wherein the spindle (10, 30) is designed as a motor spindle and the bearing flange (35) is designed as a bearing shield of the motor spindle.

13. Bearing flange (35) for a spindle (10, 30), in particular a tool or workpiece spindle, comprising at least one bearing receiving part (36) for receiving the spindle bearing (33, 34) and a fastening part (37) for fastening the bearing flange (35) to a spindle housing (32), characterized in that the bearing receiving part (36) and the fastening part (37) are elastically connected to each other by at least one elastically deformable connecting element (38).

14. Machine, in particular machine tool (2) or robot, comprising a spindle (10, 30) according to one of claims 1 to 12.

15. Digital twin for simulating a spindle (10, 30), in particular a tool and / or workpiece spindle, comprising a digital representation of at least one spindle housing (32), one spindle bearing (33, 34) and one bearing flange (35) for receiving the spindle bearing (33, 34) and for fastening it to the spindle housing (32), wherein the bearing flange (35) has at least one bearing receiving part (36) for receiving the spindle bearing (33, 34) and one fastening part (37) for fastening the bearing flange (35) to the spindle housing (32), wherein the bearing receiving part (36) and the fastening part (37) are elastically connected to each other by at least one elastically deformable connecting element (38), characterized in that the elastic deformation of the elastically deformable connecting element (38) as a result of an external force acting on the spindle can be simulated by means of the digital twin.

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