Machine tools, hydraulic devices, hydraulic systems, and workpiece machining methods for machining workpieces

Abstract

The present invention provides a machine tool 1000 for machining a workpiece using a machining fluid. The machine tool 1000 comprises a workspace 1 for machining a workpiece, at least one fluid consumption unit 2 capable of supplying a machining fluid for workpiece machining to the workspace 1, a hydraulic system 3 that supplies the machining fluid to at least one fluid consumption unit 2, and a control device 4 for controlling the machine tool. The hydraulic system 3 comprises a pump 32 for transporting the machining fluid, an inlet 35 through which the machining fluid transported by the pump 32 is guided to at least one fluid consumption unit 2, a first measuring unit 351a and a second measuring unit 351b assigned to the inlet, and a flow rate measuring device 351. These are each configured to detect the flow rate of the machining fluid in the inlet 35. In this example, the control device 4 is configured to control the machine tool 1000 based on a first measured value detected by the first measuring unit 351a and / or a second measured value of the flow rate of the machining fluid passing through the inlet 35 detected by the second measuring unit 351b.

Description

Technical Field

[0001] The present invention relates to a machine tool for workpiece machining, a hydraulic device used in the machine tool, a hydraulic system, and a workpiece machining method.

Background Art

[0002] In the field of workpiece machining, a machining fluid, particularly a coolant lubricant (abbreviated as CL), is usually used, thereby improving tool wear and machining quality in workpiece machining. CL is generally an oil-water emulsion and is supplied to the machining area, that is, the area where the tool removes material from the workpiece.

[0003] By using the machining fluid, the friction between the workpiece and the tool is reduced, and the heat inevitably generated during workpiece machining is dissipated from the machining area.

[0004] The machining fluid serves to cool the tool or the workpiece and reduce tool wear. Further, the machining fluid can also be used in the machining process to remove chips generated from the machining area. Furthermore, the machining fluid may have corrosion inhibition characteristics, and as a result, the workpiece and / or the tool are protected from corrosion during or after workpiece machining.

[0005] The above effects improve the machining quality, and thus the dimensional accuracy of the workpiece, for example, the surface quality, leading to high-quality manufacturing workpieces.

[0006] In the prior art, it was customary to supply a machining fluid to a machine tool using a speed control pump. The supply by the pump is always performed at a predetermined relatively high supply pressure (about 40 to 100 bar) so that no risk is assumed regarding the supply during workpiece machining. This prevents an insufficient supply to the machining area during machining and avoids a situation where, for example, the tool used becomes unusable.

[0007] During complete workpiece machining in such high pressure ranges, the general provision of a constant supply pressure inevitably involves high energy requirements for the pump. Depending on the configuration of the components supplying the machining fluid, and especially depending on their fluid-mechanical properties, this can result in high power loss in that the pump provides a supply pressure higher than actually required.

[0008] As a result, the lifespan of pumps and other hydraulic components used to supply processing fluids is shortened, increasing maintenance effort and costs. Furthermore, the energy consumption for supplying processing fluids can be unnecessarily high, leading to significant energy costs that cannot be ignored in mass production environments. [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] Therefore, the present invention aims to overcome the problems known in the prior art and to provide the possibility of workpiece machining using a machining fluid that is improved compared to the prior art, in particular by reducing energy consumption during workpiece machining and the load on hydraulic components. [Means for solving the problem]

[0010] To achieve this objective, a machine tool for workpiece processing described in claim 1, a hydraulic apparatus described in claim 20, a hydraulic system described in claim 21, and a workpiece processing method described in claim 22 are provided.

[0011] Each dependent claim herein relates to a preferred embodiment that may be provided individually or in combination.

[0012] According to a first aspect of the present invention, a machine tool is provided for machining a workpiece using a machining fluid, particularly a cooling lubricant.

[0013] The machine tool comprises a workspace in which workpiece processing is performed, at least one fluid consumption unit capable of supplying processing fluid for workpiece processing to the workspace, a hydraulic system configured to supply processing fluid to the at least one fluid consumption unit, and a control device for controlling the machine tool. The hydraulic system comprises a pump for supplying processing fluid, an inlet into which the processing fluid supplied by the pump is led to at least one fluid consumption unit, and a flow rate measuring device assigned to the inlet, having at least one first measuring unit and a second measuring unit, each configured to detect the flow rate of the processing fluid passing through the inlet, particularly the volumetric flow rate of the processing fluid. In this example, the control device is configured to control the machine tool, particularly the hydraulic system as part of the machine tool, based on a first measured value of the flow rate of the processing fluid passing through the inlet, particularly the volumetric flow rate, detected by the first measuring unit and / or a second measured value detected by the second measuring unit.

[0014] During workpiece machining, the machining fluid flows into the machine tool's workspace through the fluid consumption section, is supplied to the machining area, and supports the workpiece machining there, as explained at the beginning.

[0015] In this example, the fluid consumption unit can be understood as any component of a machine tool that can supply machining fluid for workpiece processing into the workspace. In this example, discharge into the workspace may occur directly or via nozzles, sprayers, or other components attached to the fluid consumption unit. These components allow the flow of the machining fluid and function as supply points.

[0016] The throughflow rate should be understood as any variable that indicates the amount of processing fluid that flows through each component (e.g., the inlet or fluid consumer) over a given time. This may be a non-exclusive volumetric flow rate, mass flow rate, or flow velocity, and for example, the mass flow rate or volumetric flow rate can be calculated using information on density and flow cross-sectional area. Naturally, any reference to throughflow rate in this specification may be replaced by a reference to one of the aforementioned variables.

[0017] Preferably, a tool having an internal flow path is attached to the fluid consumption unit, and the machining fluid is discharged into the workspace through the tool. This not only directly supplies the machining fluid to the machining area through the tool, but the tool is further cooled by the machining fluid that flows into the inside of the tool. As a result, the concept of internal CL supply known in the prior art is realized.

[0018] Ultimately, the decisive factor in workpiece machining is the amount of machining fluid supplied, not the supply pressure at the fluid consumption point.

[0019] Due to the hydrodynamic characteristics of the supply point in the fluid consumption section, such as the geometric dimensions of the opening or duct through which the processing fluid passes into the workspace, the supply pressure, beyond a certain value, has little to no significant effect on the flow rate, particularly the volumetric flow rate. Therefore, increasing the supply pressure primarily increases the output loss of the hydraulic system without significantly increasing the supply of processing fluid in the process. As a result, the components of the hydraulic system are unnecessarily overloaded, and unnecessarily high energy costs are incurred.

[0020] This situation, where, in conventional technology, the supply pressure at the fluid consumption section is generally maintained within the 40-100 bar range mentioned at the beginning using a pressure measurement unit of the hydraulic system, corresponds to pressure control. In particular, considering the numerous usable supply points, each with different hydrodynamic characteristics, the degree of the associated drawbacks can vary greatly depending on the supply point.

[0021] This invention overcomes the disadvantageous concept of pressure control during the supply of machining fluids, and in particular provides hardware necessary for reliable flow rate control or volumetric flow rate control as part of a machine tool, especially when the controlled object is volumetric flow rate instead of conventional pressure control. This makes it possible to always maintain optimal operating conditions for the hydraulic system, even when using multiple hydrodynamically different supply points.

[0022] To implement flow rate control or flow rate adjustment, it is necessary to be able to reliably and as accurately as possible measure the flow rate of the processing fluid at the inlet. However, this is not easy to achieve due to the large number of available supply points and the resulting large differences in flow rates or volumetric flow rates at the inlet, i.e., the relatively wide range of values ​​that must be covered.

[0023] In this example, the hydraulic system can be set to provide a flow rate defined as the volumetric flow rate at the inlet during workpiece processing, in the range of 0.001 liters per minute (l / min) to 80 l / min, or in the range of 0.01 to 50 l / min, which in particular correspond to the range of values ​​to be covered as described above.

[0024] The inventors have found that the accuracy required to achieve robust throughput control or its adjustment can be achieved over the aforementioned wide range of values by using the aforementioned throughput measuring device having at least two measuring units independent of each other. The two measuring units complement each other, thereby covering the aforementioned wide range of values and providing the measurement accuracy required for flow control or its adjustment for both small and large volumetric flows.

[0025] As a result, for example, it becomes possible to reliably and accurately detect a flow rate defined as a volumetric flow rate in a range from several hundred ml per minute to over 30 l / min.

[0026] The former is, for example, the case of internal CL supply through a drill having a diameter of several millimeters, and the latter is a typical value in the case of internal CL supply through a milling head in the case of large-area workpiece machining.

[0027] In this example, by performing the two measurements independently, it is always possible to make a highly reliable determination about the current throughput in the inflow path, which covers the entire range of the throughput in the inflow path that has a large variation in the context of the present invention and forms the basis for highly reliable throughput control.

[0028] Therefore, with the above configuration of the machine tool or the hydraulic device, it becomes possible to reliably perform reliable flow control or volumetric flow control during supply to the fluid consumption part. Therefore, it is possible to always provide an optimal flow rate or volumetric flow rate.

[0029] Therefore, the present invention can effectively avoid an adverse operating state in which an "excessive high pressure" is applied to a large number of supply points having different hydrodynamic configurations by flow control or volumetric flow control. As a result, the load on the hydraulic device and the output loss occurring in the hydraulic device can be significantly reduced, and thus the energy cost during the operation of the machine tool can be reduced, and the service life of the hydraulic device itself can be extended.

[0030] In particular, with respect to the concept of internal CL supply, the machine tool or hydraulic system for controlling its flow rate according to the present invention makes it possible to always set the optimal flow rate for each tool having an internal flow path, thereby achieving optimal cooling and lubrication with the lowest possible power loss in the hydraulic system.

[0031] In contrast, conventional pressure control is extremely inaccurate, making it impossible or extremely difficult to determine the optimal pressure for each process. Furthermore, such values ​​cannot be applied to other machine tools because the pressure in the fluid consumption section changes due to differences in flow paths, even for the same tool or process.

[0032] In contrast, the present invention has the advantage that it does not depend heavily on the specific characteristics of individual machine tools, and therefore the optimal value determined on a machine tool for the flow rate of individual tools with internal CL supply can be transferred to other machine tools without any problems, yielding substantially the same results.

[0033] A further negative consequence of conventional pressure control with "excessively high" pressure is that the work fluid is excessively atomized when introduced into the workspace. In particular, if a mist extractor, which is commonly used in this area, is used to discharge the atomized work fluid, the increased atomization leads to increased work fluid consumption and high energy costs for operating the mist extractor.

[0034] In contrast, according to the present invention, a controlled amount of processing fluid is introduced, i.e., not in excess, and as a result, the advantage is obtained that oversupply, which in turn leads to unnecessarily high atomization, can be effectively avoided. The control device is preferably configured to control the hydraulic device, particularly its pump, based on a detected first measured value and / or a second measured value, and more specifically, it is preferably controlled by setting the operating parameters of the pump that define the discharge capacity.

[0035] The machine tool is preferably a numerically controlled machine tool, and the control device is configured to control various actuators of the machine tool. In addition to the drive unit for the machining equipment, such as the machining spindle, the actuators may include, for example, the drive unit for the workpiece support, such as the machining table.

[0036] The machine tool may optionally be equipped with two control devices: one for the hydraulic system and one for other actuators not belonging to the hydraulic system. In this example, these two control devices are preferably coupled to each other.

[0037] The flow rate measuring device may preferably include an additional measuring unit for flow rate, which further improves the measurement accuracy within the range of values ​​to be measured.

[0038] The flow rate measuring device preferably includes an evaluation unit configured to select a reference value to be used for controlling the machine tool from two detected measured values. Alternatively, the evaluation unit may be configured to determine the resulting flow velocity value from the two detected measured values, for example, by a weighted average of the detected measured values, the weighting coefficients themselves preferably depending on one or both of the detected measured values. The resulting through flow rate value can be used for controlling the machine tool in this example.

[0039] This allows for a more appropriate consideration of the differences between the two measuring units, particularly their measurement range and measurement error, thereby further improving the accuracy of the control.

[0040] In a preferred embodiment, the flow rate measuring device is a volumetric flow rate measuring device, thereby defining the flow rate passing through at least the inlet as the volumetric flow rate.

[0041] In a preferred embodiment, the first measuring unit and the second measuring unit are arranged in series with respect to the flow direction of the processing fluid in the inlet.

[0042] As a result, the measured values ​​are detected sequentially, and the detected measured values ​​are related to the same fluid flow.

[0043] In a preferred embodiment, the measurement range of the first measurement unit differs from the measurement range of the second measurement unit, and in particular, neither of the two measurement ranges is a subset of the other.

[0044] This allows the two measuring units to complement each other to cover as completely as possible a wide range of possible flow rates.

[0045] The measurement range of the measuring unit may be either the nominal measurement range or the technical measurement range, and it is a range that can accurately detect the measured value of the flow rate to be controlled and is therefore usable for control.

[0046] In this example, the measurement range indicates the range of values ​​for the variable to be measured, in this case the flow rate (e.g., volumetric flow rate), within which the measurement error remains within a certain limit. With respect to volumetric flow rate, the absolute maximum measurement error of the first measurement unit within its measurement range is more preferably 1.5 l / min or less, even more preferably 0.75 l / min or less, and particularly preferably 0.1 l / min or less. Furthermore, preferably, the absolute maximum measurement error in the measurement range of the second measurement unit is 8 l / min or less, more preferably 5 l / min or less, even more preferably 2.5 l / min or less, and particularly preferably 1 l / min or less.

[0047] In a preferred embodiment, the measurement range of the first measurement unit and the measurement range of the second measurement unit overlap in the overlapping region.

[0048] As a result, the two measurement ranges can be combined particularly well without allowing excessively large measurement errors in the transition region from one measurement range to the other.

[0049] In a preferred embodiment, the measurement range of the first measuring unit is in the range of 0 to 30 l / min, preferably in the range of 0.01 to 15 l / min, and / or the measurement range of the second measuring unit is in the range of 1 to 80 l / min, preferably in the range of 1 to 50 l / min.

[0050] In a preferred embodiment, the measurement ranges of the first and second measuring units and the minimum volumetric flow rate of the pump are adjusted relative to each other so that the minimum volumetric flow rates are located within an overlapping region.

[0051] Minimum volumetric flow rate refers to the lowest volumetric flow rate that the pump can provide during normal operation. Attempts to set a lower volumetric flow rate may result in unfavorable operating conditions, such as undesirable overheating or resonant vibration of mechanical components, which do not accurately correspond to proper operation.

[0052] In a preferred embodiment, the volumetric flow rate operating range of the pump is a subset of the combined set of measurement ranges of the first and second measurement units.

[0053] As a result, the entire range of volumetric flow rates achievable by the pump falls within the measurement range obtained by expanding the two measurement units.

[0054] In this example, the volumetric flow rate operating range indicates the volumetric flow rate that the pump can supply based on its factory specifications, and the lower limit of the volumetric flow rate operating range usually corresponds to the minimum volumetric flow rate, but is not necessarily so.

[0055] In a preferred embodiment, the volumetric flow rate operating range of the pump is 0.1 to 80 l / min, preferably 1 to 50 l / min, and particularly preferably 5 to 40 l / min.

[0056] Preferably, the pump may be configured to create a pressure of up to 100 bar, preferably up to 80 bar, and particularly preferably up to 5 bar at the inlet.

[0057] As a result of volumetric flow rate control, it is no longer necessary to provide the highest possible supply pressure to achieve a specific minimum volumetric flow rate, allowing the pump itself to be made smaller.

[0058] In a specific embodiment, if it is confirmed that the flow rate measurement or volumetric flow rate measurement is particularly accurate, the volumetric flow rate operating range of the pump is 5 to 36 l / min, the first measurement range is 0.01 to 15 l / min with an absolute maximum measurement error of 0.75 l / min, and the second measurement range is 1 to 50 l / min with an absolute maximum measurement error of 2.5 l / min.

[0059] In a preferred embodiment, the machine tool further comprises a setpoint transmitter, through which a setpoint is provided for the flow rate, in particular the volumetric flow rate, of the processing fluid in at least one fluid consumption section.

[0060] In this example, the control device is preferably configured to control the hydraulic system in particular to control the flow rate in at least one fluid consumption unit, based on a setpoint provided by a setpoint transmitter and a detected first measured value and / or a detected second measured value, or a determined resulting flow rate value.

[0061] In this example, the setpoint transmitter may be implemented as a separate component of the machine tool or as part of the control system. Alternatively, the setpoint transmitter may be located externally, for example, in an external data management system connected to the machine tool via a data interface.

[0062] As a result, the hydraulic system can be individually adapted to any desired tool, and the relevant tool parameters are read out and used for control, making it particularly advantageous to use the optimal flow rate, especially the optimal volumetric flow rate, which is predetermined and stored for a particular tool, for control.

[0063] In a preferred embodiment, the control device is configured to set the operating parameters of the hydraulic pump that determine the discharge capacity, particularly the pump discharge rate or rotational speed, based on a provided setpoint and a detected first measured value and / or a detected second measured value, or the resulting determined flow rate.

[0064] In a preferred embodiment, the hydraulic system further includes a bypass device positioned between the inlet and the pump.

[0065] As a result, a portion of the processing fluid being pumped can be diverted before it enters the inlet, allowing for a flow rate or volumetric flow rate at the inlet that is lower than the pump's minimum volumetric flow rate. The return flow that flows through the bypass device is, for example, returned to a fluid tank for the processing fluid.

[0066] In a preferred embodiment, the bypass device includes at least one through-flow adjustment means through which the flow rate of the return flow of the machining fluid flowing through the bypass device can be adjusted.

[0067] Such adjustment means can adjust the flow rate in the form of a throttle means or a controllable bypass valve that can be controlled by a control device, for example, by changing the flow resistance through a bypass device.

[0068] Instead of a controllable bypass valve, it is also possible to use a bypass pump that can be controlled by the control device, either as an alternative or additional measure, by setting the operating parameters of the bypass pump, in particular, which determine the delivery capacity.

[0069] The control device is preferably configured to set operating parameters for a flow rate adjustment means that determines the return flow, based on a detected first measured value and / or a detected second measured value, or based on a determined resulting flow rate value and / or a provided set value, in order to control the flow rate in at least one fluid consumption unit.

[0070] In this way, the controller is supplemented by an additional adjustment screw, making it possible to achieve controllable flow rates or volumetric flow rates in inflows below the minimum volumetric flow rate. In this example, control of the bypass valve preferably includes setting the opening degree of the bypass valve or setting the flow resistance of the bypass valve.

[0071] In a preferred embodiment, the bypass device includes a third measuring unit configured to detect the flow rate, in particular the volumetric flow rate, of the return flow of the processing fluid flowing through the bypass device.

[0072] In this example, the control device is preferably configured to further control the hydraulic system based on an actual value detected by a third measuring unit of the return flow rate.

[0073] In this example, the control device is configured to additionally set the operating parameters of the pump that determines the discharge capacity and / or the operating parameters of the flow rate adjustment means of the bypass device that determines the return flow, based on the detected measured values ​​of the return flow rate.

[0074] In this way, information regarding the return flow in the bypass device can also be used for control, and this information can be taken into consideration during the control process.

[0075] Preferably, the measurement range of the third measuring means is in the range of 0 to 30 l / min, more preferably in the range of 0.01 to 15 l / min, and particularly preferably in the range of 0.01 to 10 l / min. In this example, the absolute maximum measurement error in the measurement range of the third measuring unit is preferably 3 l / min or less, more preferably 1.5 l / min or less, even more preferably 0.75 l / min or less, and particularly preferably 0.1 l / min or less.

[0076] In a preferred embodiment, at least one fluid consumption unit is a tool interface for receiving a tool, and the tool interface comprises at least one internal flow path. In this example, the tool interface is configured to introduce the machining fluid directed thereto into the tool housed therein or into at least one of its flow paths, and to supply the machining fluid to the workspace through the flow path. This corresponds to the concept of internal CL supply described above, where the machining fluid is discharged particularly near the machining area, further cooling the tool from the inside.

[0077] In this example, the tool interface may be designed to accept or hold one or more different tool types, for example, for milling tools and / or drilling tools, turning tools, or grinding tools with internal CL feeding.

[0078] Alternatively, at least one fluid consumption unit may also be a tool holder interface for receiving a tool holder, and a tool can be received within the tool holder interface. In this example, the tool holder has at least one internal flow path, and the tool holder interface is configured to introduce machining fluid into the tool holder or at least one flow path of the tool holder and to supply the machining fluid to the workspace through the flow path. In this way, if the tool used for machining does not have its own fluid duct, the fluid is supplied via the tool holder.

[0079] In a preferred embodiment, the tool interface is designed as a machining spindle, and the accepted tool can be rotationally driven through the machining spindle.

[0080] In a preferred embodiment, the setpoint transmitter is configured to set or define a flow rate setpoint in the fluid consumption unit or tool interface, depending on the tool received therein, and in particular depending on the tool parameters. Preferably, these tool parameters are obtained from a tool database and may correspond to a nominal tool-specific setpoint flow rate or a set volumetric flow rate. Preferably, in this example, these tool parameters are obtained from the pump characteristic curve stored in the tool database of the received tool.

[0081] As a result, control can be performed based on a predetermined flow rate or volumetric flow rate that is optimal for a particular tool. In this example, "optimal" can be understood as an operating condition that minimizes power loss in the tool while minimizing the amount of machining fluid supplied. The minimum amount may also be tool-specific and predetermined.

[0082] In a preferred embodiment, the setpoint transmitter is configured to define the setpoint based on at least one machining parameter in the control device for machine tool machining, either additionally or alternatively.

[0083] As a result, flow rate control tailored to each processing step can be implemented, and the amount of processing fluid supplied can be adjusted according to the processing, preventing insufficient or excessive supply.

[0084] The machining parameters are preferably the cutting speed of the tool, the feed rate of the tool, or the depth of tool penetration into the workpiece being machined.

[0085] In a preferred embodiment, the control device is further designed for monitoring the process of workpiece machining in the workspace, and in this context is configured to adjust at least one machining parameter of the workpiece machining based on a detected first measured value and / or a detected second measured value, or a determined resulting flow rate value.

[0086] The adjustable machining parameters are preferably the machining speed of the tool and / or the workpiece being machined, and the machining speed may be, for example, the cutting speed of the tool relative to the workpiece, the feed rate of the tool relative to the workpiece, or the cutting force or contact force between the workpiece and the tool.

[0087] The measured values ​​detected by the measuring unit provide information about the amount of machining fluid supplied during workpiece machining, which can be used as a starting point for detecting unfavorable or abnormal operating conditions. Thus, the measured values ​​can provide information about excessively fast feed rates or excessively slow cutting rates. In this example, tool damage (which can interfere with the supply of machining fluid) or insufficient chip removal (which can also interfere with the supply of machining fluid) may be considered abnormal, both of which result in lower-than-normal machining quality.

[0088] In a preferred embodiment, the control device is further configured to instruct the machine tool to stop if, during the process monitoring, a first measured value detected is outside a first setpoint range, and / or a second measured value detected is outside a second setpoint range.

[0089] As a result, economically costly damage to tools and / or workpieces under certain circumstances can be prevented before it occurs.

[0090] The setting range is preferably determined based on a fixed setpoint value, particularly on a maximum allowable relative error of, for example, ±75%, ±50%, or ±25%. Alternatively, the setpoint range may be defined by an explicit limit value.

[0091] The effective values ​​used in the process monitoring described above can also preferably be determined from two measured values.

[0092] The hydraulic system preferably includes a temperature measuring unit assigned to the inlet for detecting the temperature of the machining fluid and / or a pressure measuring unit assigned to the inlet for detecting the pressure of the machining fluid. These are coupled to a control device, and the control of the machine tool may optionally be additionally performed based on the values ​​detected by these measuring units, thereby further improving flow rate control or process monitoring, particularly the detection of abnormal operating conditions.

[0093] According to a second aspect of the present invention, a hydraulic system for a machine tool is provided that embodies a preferred embodiment of the first aspect or machine tool.

[0094] Thus, existing machine tools are complemented by hydraulic systems, and therefore, machine tools according to the present invention can be obtained without the need to provide entirely new machine tools.

[0095] According to a third aspect of the present invention, a hydraulic system for use in a machine tool is provided, comprising a hydraulic device configured to supply a machining fluid for workpiece machining to at least one fluid consumption section of the machine tool, and a control device. The hydraulic device comprises a pump for delivering the machining fluid, an inlet for directing the machining fluid delivered by the pump to at least one fluid consumption section, and a flow rate measuring device comprising at least one first measuring unit and one second measuring unit assigned to the inlet and configured to detect the flow rate of the machining fluid passing through the inlet, respectively. The control device is at least configured to control the hydraulic device by setting operating parameters that determine the discharge capacity of the pump in particular, based on a first measured value detected by the first measuring unit and / or a second measured value of the flow rate of the machining fluid passing through detected by the second measuring unit.

[0096] In this way, the possibility is provided to modify existing machine tools with hydraulic systems, along with their own control devices.

[0097] Therefore, in contrast to the provision of a hydraulic system according to the second embodiment, an independent hydraulic system having its own control device is provided, for example, when an existing control device of a machine tool is intended or usable to control the hydraulic system (e.g., due to incompatibility in data exchange, etc.).

[0098] The hydraulic apparatus of the hydraulic system can be designed according to each of the hydraulic apparatuses described in the above-described embodiments of the machine tool, and as a result, no further explanation is required at this point.

[0099] In this example, the control device for the hydraulic system may have the same functions as the control device for the machine tool described above with respect to the hydraulic system of the machine tool.

[0100] The control device for the hydraulic system preferably corresponds to the control device for the machine tool, and thereby the hydraulic system according to the third embodiment basically corresponds to a combination of the hydraulic device and the control device for the machine tool according to the first embodiment of the present invention.

[0101] However, as an alternative to the above embodiments, the control unit for the hydraulic system may be provided separately, and in particular, coupled to the control unit of the machine tool for data and signal transmission, so that the control units can access each other's data for control purposes.

[0102] The hydraulic system preferably includes a setpoint transmitter, through which a setpoint value for the flow rate in at least one fluid consumption unit or the volumetric flow rate of the processing fluid is provided. This setpoint transmitter is preferably designed as part of the control unit of the hydraulic system.

[0103] In this example, the control device for the hydraulic system is preferably configured to control the hydraulic system based on a setpoint provided by a setpoint transmitter and a detected first measured value and / or a detected second measured value, in order to control the flow rate through at least one fluid consumption unit.

[0104] The control device for the hydraulic system is preferably configured to set operating parameters that determine the discharge capacity of the hydraulic pump, particularly the pump discharge rate or rotational speed, based on a provided set value and a detected first measured value and / or a detected second measured value.

[0105] If the hydraulic system includes a bypass device, the control device of the hydraulic system is preferably configured to control the bypass device, and in particular to set one of the operating parameters of the flow rate adjustment means of the bypass device that determines the return flow through the bypass device.

[0106] A fourth aspect of the present invention provides a method for machining a workpiece using a machine tool, particularly a machine tool according to the first aspect or a preferred embodiment in this respect. The method includes at least supplying a machining fluid to the working space of the machine tool via at least one fluid consumption unit of the machine tool; operating a pump for transporting the machining fluid through an inflow to at least one fluid consumption unit; detecting a first measured value of the flow rate through, particularly the volumetric flow rate of the machining fluid at a first point of the inflow; detecting a second measured value of the flow rate through, particularly the volumetric flow rate of the machining fluid at a second point of the inflow; and controlling the machine tool for machining a workpiece based on the detected first measured value and / or the detected second measured value, each of which is performed at least before and / or during machining of the workpiece placed in the working space by the tools of the machine tool.

[0107] As a result, a method for processing a workpiece is provided, which is characterized by the advantages already described above in the process of the machine tool according to the present invention, and these advantages will not be described again here. The same applies to preferred embodiments of the method described below, corresponding to each preferred embodiment of the machine tool.

[0108] In this example, the machine tool may be configured to drive the tool and / or workpiece during the machining process.

[0109] The first and second points of the inlet are preferably located in series with respect to the flow direction of the processing fluid.

[0110] The first measured value is preferably detected by the first measuring unit, and the second measured value is preferably detected by the second measuring unit, with their respective measuring ranges being different from each other. The descriptions made regarding the measuring range and measurement error for machine tools also apply here.

[0111] The pump operates within a volumetric flow rate operating range, preferably 1 to 50 l / min, more preferably 5 to 40 l / min.

[0112] In a preferred embodiment, the method includes providing a set value for the flow rate of the machining fluid through at least one fluid consumption unit during workpiece machining, and the control of the machine tool is further performed according to the provided set value.

[0113] Preferably, this method further includes the step of selecting one of the two detected measured values ​​as a reference value, and the control of the machine tool is performed according to the selected reference value.

[0114] Alternatively, this method may include determining the resulting flow rate value based on the detected first and second measured values. The determination is preferably performed by a weighted average of the two detected measured values, where the weighting coefficients used to weight the measured values ​​in the averaging process preferably depend on one or both of the detected measured values ​​themselves.

[0115] The fluid consumption section is preferably a tool interface for receiving a tool having an internal flow path, as described above.

[0116] In this example, providing a set value preferably involves setting a set value based on the tool received, and more particularly based on tool parameters. For this purpose, providing a set value preferably involves reading tool parameters, particularly the nominal set flow rate or set volume flow rate of the received tool, from a tool database.

[0117] In this example, reading the tool parameters preferably involves reading from the pump characteristic curve of the accepted tool stored in the tool database.

[0118] Providing a set value preferably includes, additionally or alternatively, defining the setting of the set value based on at least one machining parameter of the workpiece machining. For this purpose, providing a set value preferably includes reading one or more machining parameters of the workpiece machining, particularly the cutting speed of the tool, the feed rate of the tool, or the depth of tool penetration into the workpiece being machined, from the control device of the machine tool.

[0119] The control of the machine tool preferably further includes adjusting the setting of at least one machining parameter for workpiece machining in the control device of the machine tool based on a detected first measured value and / or a detected second measured value. The at least one machining parameter to be set is preferably the machining speed of the tool and / or the workpiece being machined, in particular the cutting speed of the tool relative to the workpiece or the feed rate of the tool relative to the workpiece or the cutting force or contact force between the tool and the workpiece.

[0120] In a preferred embodiment, the control of the machine tool further includes controlling the flow rate through at least one fluid consumption section, particularly the volumetric flow rate of the machining fluid, based on a provided setpoint and a detected first measured value and / or a detected second measured value, and preferably further includes setting operating parameters of a pump that determines the discharge capacity, based on a provided setpoint and a detected first measured value and / or a detected second measured value.

[0121] Further embodiments and their advantages, as well as more specific exemplary embodiments of the above-described embodiments and embodiments, are described below with reference to the drawings shown in the attached drawings. [Brief explanation of the drawing]

[0122] [Figure 1] A schematic diagram of a first exemplary embodiment of a machine tool according to the present invention is shown. [Figure 2] A schematic diagram of a second exemplary embodiment of the machine tool according to the present invention is shown. [Figure 3A] A schematic diagram of a third exemplary embodiment of the machine tool according to the present invention in an alternative form is shown. [Figure 3B] A schematic diagram of a third exemplary embodiment of the machine tool according to the present invention in an alternative form is shown. [Figure 4] A schematic flowchart of an exemplary embodiment of the method according to the present invention for machining a workpiece is shown. [Figure 5] The pump characteristic curves and operating points of different tools for use in a machine tool according to the present invention having an internal CL supply are shown. [Figure 6] This shows the measurement results of hydraulic parameters during workpiece machining using the present invention with internal CL supply via a hydraulic system. [Figure 7] This shows the results of measuring tool wear in use for workpiece machining using the present invention with internal CL supply via a hydraulic system. [Figure 8] This table shows the machining results during workpiece machining using the present invention with internal CL supply via a hydraulic system. [Modes for carrying out the invention]

[0123] It is emphasized that the present invention is by no means limited to the exemplary embodiments and features of those embodiments described below. The present invention further includes modifications of the exemplary embodiments mentioned, in particular those arising from modifications and / or combinations of individual or multiple features of the exemplary embodiments described within the scope of protection of the independent claims.

[0124] Figure 1 shows a schematic diagram of a first exemplary embodiment of the machine tool 1000 according to the present invention.

[0125] The machine tool 1000 comprises a workspace 1 on which a workpiece 1002 is machined, a machining spindle 2 as a fluid consumption unit capable of receiving and rotating a tool 1001, a hydraulic system 3 that supplies a cooling lubricant (CL) to the machining spindle 2, and a control device 4 configured to control the machine tool 1000.

[0126] CL for workpiece machining can be supplied to the workspace 1 via a fluid consumption unit designed as a machining spindle 2. Here, the machining spindle 2 corresponds to a tool interface, and CL can be supplied via the tool interface to a tool 1001 having at least one internal flow path. In this way, the tool is supplied to the workspace 1 via at least one flow path of the tool 1001, thereby realizing the concept of internal CL supply.

[0127] The supply of CL to the machining spindle 2 for internal CL supply is performed via a hydraulic system 3, which includes a tank 11 in which the CL is stored, a pump 32 for transporting the CL, and an inlet 35 through which the CL is guided from the pump 32 to the machining spindle 2. In this example, a pressure relief valve 33 protects the hydraulic system 3 from damage when the volumetric flow rate transported by the pump 32 and passing through the inlet 35 is interrupted.

[0128] The CL supplied to the machine tool 1000 is recovered and returned to the tank 31 through the outlet 36 of the hydraulic system, which has an outlet filter 361.

[0129] The hydraulic system may also be equipped with a pressure sensor 352 and / or a temperature sensor 353 at the inlet 35, as shown in Figure 1. As a result, the control device can comprehensively grasp the state of CL in the inlet passage 35.

[0130] Furthermore, the hydraulic system 3 has a flow rate measuring device 351, which is assigned to the inlet and has a first flow rate sensor 351a and a second flow rate sensor 351b, which are arranged in series with respect to the flow direction of CL in the inlet 35 and are configured to detect the volumetric flow rate of CL in the inlet 35.

[0131] The two flow sensors 351a and 351b preferably have different, non-inclusive measurement ranges, and these measurement ranges are complementary, so that measurement errors can be minimized and the volumetric flow rate in the inlet passage 35 can be reliably detected over the entire volumetric flow rate operating range of the pump 32. Preferred values ​​for the measurement ranges can be obtained from the above overview.

[0132] The control device 4 is coupled to the hydraulic system 3, which is coupled to at least two flow sensors 351a and 351b.

[0133] Furthermore, in this exemplary embodiment, the control device 4 is configured to control the hydraulic system 3 or to control the CL volume flow rate in the machining spindle 2 during machining of the workpiece 1002. For this purpose, the control device 4 has a setpoint transmitter 41 through which a setpoint value for the CL volume flow rate in the machining spindle 2 is provided.

[0134] The control device 4 may, alternatively or additionally, be connected to other actuators of the machine tool, such as the drive unit of the machining spindle 2.

[0135] The set value may be manually set by the machine operator in the set value transmitter 41. Alternatively or additionally, the set value transmitter 41 may be configured to access the tool parameters of the tool 1001 stored in the memory device 43 of the control device and determine the set value based thereon. Alternatively or additionally, the set value transmitter 41 may be configured to access the tool database via the data interface 42 of the control device 4, read the tool parameters of the tool 1001 thereon, and determine the set value based thereon. Alternatively or additionally, the set value may be transmitted to the set value transmitter 41 via the data interface 42.

[0136] To achieve volumetric flow rate control, the control device 4 is coupled to the pump 32 of the hydraulic system 3 and is configured to control the operating parameters of the pump 32, particularly the rotational speed, which determines the discharge capacity, based on a set value provided by the set value transmitter 41, a first measured value detected by the first flow sensor 351a, and / or a second measured value detected by the second flow sensor 351b, with respect to the volumetric flow rate of CL in the inlet 35.

[0137] The above configuration of the machine tool 1000 or hydraulic system 3 makes it possible to accurately control the volumetric flow rate while supplying CL to the machining spindle 2 during machining, independently of the hydrodynamic characteristics of the tool 1001 accepted therein. This volumetric flow rate control, achieved for multiple tools, effectively avoids unfavorable operating conditions involving "excessively high" pressure that occur in conventional techniques during pressure control. As a result, the load on the hydraulic system 3 and power losses within the hydraulic system can be significantly reduced, thereby lowering the energy costs during operation of the machine tool 1000 and increasing the service life of the hydraulic system 3 itself.

[0138] The combination of the hydraulic system 3 and control device 4 of the machine tool 1000 shown in Figure 1 further corresponds to an exemplary embodiment of the hydraulic system according to the present invention, since the control device 4 of the machine tool 1000 is configured to control at least the hydraulic system 3.

[0139] Alternatively, a separate control device (not shown) for the hydraulic system may be provided, which can be coupled to the machine tool's control device, and the latter is configured to control other actuators of the machine tool.

[0140] Figure 2 shows a schematic diagram of a second exemplary embodiment of the machine tool 1000 according to the present invention.

[0141] The second exemplary embodiment largely corresponds to the first exemplary embodiment but differs in the presence of a bypass 34 located between the inlet 35 and the pump 32, which allows at least a portion of the CL supplied by the pump 32 to be guided to the tank 31 as a backflow. This makes it possible to supply volumetric flow rates below the minimum volumetric flow rate of the pump 32 at the inlet 35.

[0142] In this example, the bypass 34 has a flow control means designed as a controllable throttle valve 342, through which the flow rate passing through the bypass can be adjusted. For example, the flow resistance in the bypass 34 can be adjusted by setting the opening degree of the throttle valve.

[0143] Furthermore, the bypass has a dedicated third flow sensor 341, which is configured to detect the volumetric flow rate of the return flow in the bypass 34.

[0144] In this example, the volumetric flow rate supplied by the pump 32 corresponds to the sum of the volumetric flow rates in the inlet 35 and the bypass 34, which can be detected by the sensors 341, 351a, and 351b, respectively.

[0145] The control device is preferably configured to control the operating parameters of a flow rate adjustment means that determines the return flow rate based on a detected first measured value and / or a detected second measured value, or based on the determined resulting volume flow rate and / or a provided set value, in order to control the volume flow rate in at least one fluid consumption unit.

[0146] The throttle valve 342 and the third flow sensor 341 are both connected to the control device 4. In this example, in order to control the volumetric flow rate in the inlet 35, the control device is configured to control the hydraulic system 3 according to the first measured value detected by the first flow sensor 351a and / or the second measured value detected by the second flow sensor 351b and / or the third measured value detected by the third flow sensor 341 and the set value provided by the set value transmitter 41.

[0147] For this purpose, the control device 4 is configured to set the operating parameters of the pump 32 that determine the discharge capacity and / or the operating parameters of the throttle valve 342 in the bypass 34 that determine the return flow, in particular to control the volumetric flow rate in the machining spindle 2 during workpiece machining.

[0148] Figures 3A and 3B show schematic diagrams of a third exemplary embodiment of the machine tool 1000 according to the present invention in two alternative forms.

[0149] Two alternative forms of the third exemplary embodiment largely correspond to the second exemplary embodiment. For the sake of brevity, Figures 3A and 3B omit the reproduction of the left-hand portion, which is the same as in Figure 2.

[0150] An alternative embodiment of the third exemplary embodiment differs from the second exemplary embodiment in the use of an inlet filter 354 in the inlet 35, which is located downstream of the volumetric flow rate measuring device 351 in the flow direction of Figure 3A and upstream of the volumetric flow rate measuring device 351 in the flow direction of Figure 3B. Furthermore, the machine tool 1000 does not have any pressure sensors or temperature sensors in the inlet 35. The inlet filter 354 may optionally have a check valve as shown in Figures 3A and 3B.

[0151] Through the inflow filter 354, contamination in the CL can be removed upstream of the supply section, where the contamination may, for example, adversely affect machining or, under certain circumstances, even block the flow path of the tool 1001.

[0152] In this example, the inventors have found that the arrangement of the volumetric flow rate measuring device 351 downstream of the inlet filter 354, as shown in Figure 3B, achieves the best results in controlling the volumetric flow rate of the machining spindle 2, particularly because no additional components, such as the inlet filter 354, which could potentially affect the already measured CL flow rate, are located between the measurement point and the fluid consumption section or control point in the machining spindle 2. This is particularly advantageous when the inlet filter 354 is designed with a check valve, as shown in Figures 3A and 3B, through which a portion of the already measured CL flow is diverted, in some cases, before being supplied to the machining spindle 2.

[0153] Furthermore, the inflow filter 354 may also be located between the pump and the branch to the bypass 34 shown in Figure 2, which further improves the measurement results of the return flow in the bypass 34.

[0154] The inflow filter 354 can, of course, also be used in the exemplary embodiment without the bypass 34 from Figure 1, as described in Figures 3A and 3B.

[0155] Figure 4 shows a schematic flow diagram of an exemplary embodiment of the method according to the present invention for machining a workpiece on a machine tool using a machining fluid, particularly CL.

[0156] In step S1, the flow rate through the fluid consumption section during workpiece processing is given, for example, a set value for the volumetric flow rate of the processing fluid.

[0157] In step S2, the machining fluid is supplied into the working space of the machine tool via a fluid consumption unit, and this step includes substep S2.1, which operates a pump to send the machining fluid to the fluid consumption unit via an inlet.

[0158] In step S3, the first measured value of the flow rate of the processing fluid at the first point of the inlet is detected.

[0159] In step S4, a second measured value of the flow rate of the processing fluid at the second point of the inlet is detected.

[0160] In step S5, the machine tool for workpiece machining is controlled based on the set value given in step S1, the first measured value detected in step S3, and / or the second measured value detected in step S4, and this step includes substep S5.1, which sets the operating parameters that determine the discharge capacity of the pump, in particular the rotational speed, based on the provided set value and the detected first measured value and / or second measured value.

[0161] Each of the aforementioned steps is performed at least before and / or during machining of the workpiece, which is positioned in the workspace by a tool accepted by the machine tool.

[0162] Figure 5 shows exemplary pump characteristic curves and operating points for different tools W1 to W6 for use in a machine tool according to the present invention having an internal CL supply.

[0163] Here, the pump characteristic curve corresponds to the tool-specific output curve in a hydraulic system pump designed for internal CL supply, based on the volumetric flow rate of CL supplied from the pump without using a bypass.

[0164] The data for the related tools W1 to W6 can be obtained from the table below.

[0165] [Table 1]

[0166] All output curves demonstrate a substantially exponential dependence of output on the converted volumetric flow rate. Therefore, small changes in volumetric flow rate lead to significant changes in output, and consequently, significant changes in energy costs incurred during operation.

[0167] For example, in the pump characteristic curve for W5, the pressure at representative points is additionally shown. Specifically, at a volumetric flow rate of 29 l / min, the pressure is 80 bar; at a volumetric flow rate of 20.6 l / min, it is 40 bar; and at a volumetric flow rate of 13.5 l / min, it is 17 bar. Looking at the highest data point, it can be seen that when the pressure is halved, the volumetric flow rate decreases by only about 29%, but the output already decreases by about 64%. In this example, a volumetric flow rate of 20.6 l / min is sufficient for machining with tool W5, which significantly reduces the pressure and, as a result, significantly reduces the load on the hydraulic system.

[0168] The pump characteristic curves for tools W1-W6 reveal a so-called pure pressure control problem, in which, in one example, a high pressure is set on the pump to avoid the risk of CL shortage when in doubt. As a result, such a strategy usually leads to unnecessary energy costs and overload of the hydraulic system, but for certain tools, sufficient CL supply can be obtained even with significantly lower pressure and consequently lower pump output.

[0169] This invention makes it possible, in this example, to switch from pressure control to volumetric flow rate control, as is known in the prior art.

[0170] The pump characteristic curves described above can be provided to the machine tool's control system, for example, by storing them in a memory device or by interfacing with an external tool management database.

[0171] Figure 6 shows the measurement results of hydraulic parameters used in the present invention during workpiece machining using internal CL supply by a hydraulic system.

[0172] Figure 6 shows a comparison of hydraulic parameters between conventional pressure control (top figure) and volumetric flow control according to the present invention (bottom figure) while forming a hole in a workpiece using a tool W2 (drill). Further parameters for workpiece machining were as follows: -Workpiece material: AISI316 (austenitic chromium-nickel-molybdenum steel) -Cutting speed: 50m / min - Feed rate: 0.1mm - Hole depth: 180mm

[0173] In this example, a constant feed rate is selected, so the penetration depth into the workpiece is proportional to time.

[0174] Both figures show the time profile of the pressure p acting on the drill during workpiece machining, and the current volumetric flow rate Q of CL. In the case of pressure control, a pressure setting of 50 bar is predetermined, and in the case of volumetric flow rate control, a volumetric flow rate setting of 2 l / min is predetermined.

[0175] As can be seen from the figure above, the pressure p is kept almost constant at 50 bar, but the resulting volumetric flow rate Q fluctuates significantly at relatively high frequencies. Specifically, it fluctuates by approximately 3.3 l / min within a range from a minimum value of Qmin ≈ 0.5 l / min to a maximum value of Qmax ≈ 3.8 l / min, centered around an average value of Q ≈ 2.1 l / min. The volumetric flow rate Q in the drill, converted by pressure control, is highly unstable, which affects the machining quality of the workpiece and, as a result, leads to non-uniform machining results.

[0176] In contrast, the figure below shows a much less variable and extremely stable volumetric flow rate Q. Specifically, in the range from a minimum value Qmin ≈ 1.0 l / min to a maximum value Qmax ≈ 3.0 l / min, it fluctuates by approximately 2.0 l / min, centered around an average value Qmin = 2.0 l / min. The pressure profile in this example shows that, in order to maintain the set volumetric flow rate Q of 2.0 l / min, the pressure p increases almost linearly from approximately 35 bar to 45 bar as the penetration depth increases.

[0177] As a result, volumetric flow control delivers CL with lower fluctuations while maintaining substantially the same average volumetric flow rate compared to pressure control. At the same time, a lower pressure is always maintained, resulting in lower energy costs and lower load on hydraulic components, thus leading to increased lifespan compared to pressure control.

[0178] The measurement results described above demonstrate the advantages of volumetric flow rate control during workpiece machining, which can only be reliably implemented by the configuration according to the present invention of a machine tool or a hydraulic device having two measuring units.

[0179] Figure 7 shows the results of measuring tool wear in use for workpiece machining using the present invention with internal CL supply via a hydraulic system.

[0180] Figure 7 shows a comparison of the time profile of tool wear under conventional pressure control and the time profile of volumetric flow control according to the present invention during milling of a free surface by a W5 (milling cutter) tool. The additional parameters for workpiece machining were as follows: -Workpiece material: TiAl6V4 -Cutting speed: 75m / min - Feed rate: 0.12mm - Cutting width and cutting depth: 10mm and 5mm

[0181] This figure shows tool wear over the service life (minutes) of a milling cutter. Workpiece machining is performed using conventional pressure control with a set pressure p of 80 bar, and using volumetric flow control according to the present invention with a set volumetric flow rate Q of 13.4 l / min. The degree of tool wear is indicated by specifying the width of the wear surface on the free surface of the tool in μm.

[0182] As can be seen from the figure, in both the pressure control and volumetric flow control cases, a nearly equal increase in tool wear is initially shown. However, in the subsequent process, tool wear increases significantly in the case of pressure control, and towards the end, it becomes clearly distinguishable from the tool wear in the case of volumetric flow control.

[0183] As a result, the volumetric flow rate control according to the present invention also has a favorable effect on tool wear, allowing tools to be used for a longer period, reducing the frequency of replacement, and ultimately leading to lower operating costs.

[0184] Furthermore, the figure shows that the average output value of the pump for supplying CL to the tool differs by almost 10 times in both equations, and therefore, volumetric flow control according to the present invention results in significant energy savings compared to conventional pressure control.

[0185] Furthermore, the inventors have found that volumetric flow rate control yields better machining results compared to conventional volumetric flow rate control, as can be seen from the table shown in Figure 8.

[0186] The table in Figure 8 shows a comparison of the average surface roughness Ra obtained after machining a workpiece under predetermined machining conditions using a drill related to W4 and a milling cutter related to W5. In each case, the results using a conventional pressure control method and a volumetric flow control device according to the present invention are shown.

[0187] In the case of volumetric flow control, lower surface roughness was achieved for both tools despite the other machining parameters being the same, and therefore, better surface quality of the workpiece could also be achieved by using volumetric flow control.

[0188] Therefore, the volumetric flow rate controller according to the present invention also offers advantages in terms of machining quality.

[0189] Although preferred embodiments of the present invention have been described in detail above with reference to the attached drawings, the present invention is not limited to these examples.

[0190] It is again emphasized that the present invention is by no means limited to the exemplary embodiments and features of those embodiments described above.

[0191] The present invention further includes modifications of the exemplary embodiments mentioned, in particular those arising from modifications and / or combinations of features of the exemplary embodiments described within the scope of protection of the independent claims. [Explanation of symbols]

[0192] 1. Workspace 2. Machining spindle as a tool interface (fluid consumption unit) 3. Hydraulic System 4. Control devices for machine tools 31 tanks 32 pumps 33 Pressure relief valve 34 Bypass 35 Inlet 36 Outlet 341 Third flow sensor (bypass) 342 Controllable Throttle Valve 351 Volumetric flow rate measuring device 351a, 351b First flow sensor, second flow sensor (volume flow sensor, volume flow measuring device) 352 Pressure Sensor 353 Temperature Sensor 354 Inflow Filter 361 Outlet Filter 41. Setting value transmitter 42 Data Interfaces 43 Memory Devices 1000 machine tools 1001 Tools 1002 Work

Claims

1. A machine tool (1000) for workpiece processing, Workspace (1) and At least one fluid consumption unit (2) capable of supplying a machining fluid for workpiece machining, particularly a cooling lubricant, to the workspace (1) via the fluid consumption unit (2), A hydraulic device (3) configured to supply the processing fluid to at least one fluid consumption unit (2), Pump (32) for supplying the processing fluid, An inlet (35) through which the processing fluid sent by the pump (32) is guided to the at least one fluid consumption unit (2), A flow rate measuring device (351) is assigned to the inlet (35) and has at least one first measuring unit and one second measuring unit, each configured to detect the flow rate of the processing fluid in the inlet (35). A hydraulic device (3) having, A control device (4) for controlling a machine tool (1000), configured to control the machine tool (1000), particularly the hydraulic system (3), based on a first measured value of the flow rate of the processing fluid through the inlet (35) detected by a first measuring unit (351a) and / or a second measured value detected by a second measuring unit (351b), A machine tool (1000) equipped with the following.

2. The flow rate measuring device is a volumetric flow rate measuring device (351), and the flow rate in the inlet (35) is determined by the volumetric flow rate. The machine tool (1000) according to claim 1.

3. The first measuring unit (351a) and the second measuring unit (351b) are arranged in series with respect to the flow direction of the processing fluid in the inlet (35). A machine tool (1000) according to claim 1 or 2.

4. The measurement range of the first measurement unit (351a) is different from the measurement range of the second measurement unit (351b), and in particular, neither of the two measurement ranges is a subset of the other measurement range. A machine tool (1000) according to at least one of the prior claims.

5. The measurement range of the first measurement unit (351a) and the measurement range of the second measurement unit (351b) overlap in the overlapping region. A machine tool (1000) as described in at least claim 4.

6. The measurement range of the first measuring unit (351a) is in the range of 0 to 30 l / min. Preferably, the range is 0.01 to 15 l / min. The measurement range of the second measurement unit (351b) is in the range of 1 to 80 l / min. Preferably in the range of 1 to 50 l / min. A machine tool (1000) according to at least claims 2 and 5.

7. The measurement ranges of the first measurement unit and the second measurement unit (351a, 351b) and the minimum volumetric flow rate of the pump (32) are aligned with each other such that the minimum volumetric flow rate falls within an overlapping region. A machine tool (1000) according to at least claims 2 and 5.

8. The volumetric flow rate operating range of the pump (32) is a subset of the combined set of the measurement ranges of the first measurement unit and the second measurement unit (351a, 351b). A machine tool (1000) according to at least one of claims 2 and 3 to 7.

9. The volumetric flow rate operating range of the pump (32) is in the range of 0.1 to 80 l / min. Preferably in the range of 5 to 40 l / min. A machine tool (1000) according to at least claim 8.

10. The machine tool (1000) further comprises a set value transmitter (41), and a set value for the flow rate of the processing fluid in at least one fluid consumption unit (2) is provided via the set value transmitter. The control device (4) is configured to control the hydraulic system (3) based on a given set value and a detected first measured value and / or a detected second measured value, in particular to control the flow rate through at least one fluid consumption unit (2). A machine tool (1000) as described in at least one of the prior claims.

11. The control device (4) is configured to set the operating parameters of the pump (32) of the hydraulic device (3) that determine the discharge capacity, in particular the discharge amount or rotational speed of the pump (32), based on a given set value and a detected first measured value and / or a detected second measured value. A machine tool (1000) according to at least claim 10.

12. The hydraulic system (3) further includes a bypass device (34) positioned between the inlet (35) and the pump (32). A machine tool (1000) as described in at least one of the prior claims.

13. The bypass device (34) has at least one flow rate adjustment means (342), in particular a controllable bypass valve (342) or a controllable bypass pump, which can adjust the flow rate of the return flow of the processing fluid that flows through the bypass device (34). A machine tool (1000) according to at least claim 12.

14. The bypass device (34) has a third measuring unit (341) configured to detect the flow rate of the return flow of the processing fluid flowing through the bypass device (34), The control device (4) is configured to further control the hydraulic system (3) based on the measured value of the return flow rate detected by the third measuring unit (341). A machine tool (1000) according to at least claims 10 and 13.

15. The at least one fluid consumption unit is a tool interface (2) for receiving a tool (1001) having at least one internal flow path, The tool interface (2) is configured to supply the machining fluid guided to the tool interface (2) to the workspace (1) via at least one channel of the tool (1001) accepted into the tool interface (2). A machine tool (1000) as described in at least one of the prior claims.

16. The tool interface is designed as a machining spindle (2) that receives and rotates the tool (1001). A machine tool (1000) according to at least claim 15.

17. The setting value transmitter (41) is configured to define a setting value based on the tool parameters of the tool (1001) received by the tool interface (2), and / or based on at least one machining parameter of the workpiece machining in the control device (4). The machining parameters are, in particular, the cutting speed of the tool (1001), the feed rate of the tool (1001), or the penetration depth of the tool (1001) into the workpiece (1002). A machine tool (1000) according to at least one of claims 15 and 16.

18. The control device (4) is further designed for monitoring the workpiece machining process in the workspace (1) and is configured to adjust at least one machining parameter of the workpiece machining based on a detected first measured value and / or a detected second measured value, in particular the machining speed of the tool (1001) and / or workpiece (1002) being machined. A machine tool (1000) as described in at least one of the prior claims.

19. The control device (4) further, If the detected first measured value is outside the predetermined first set value range, and / or If the detected second measured value is outside the second predetermined set value range, It is configured to instruct the machine to stop the machine tool (1000). The machine tool (1000) according to claim 18.

20. A hydraulic system (3) for a machine tool (1000) according to one of claims 1 to 19.

21. A hydraulic system for use in a machine tool (1000), A hydraulic system (3) configured to supply a machining fluid for workpiece processing to at least one fluid consumption unit (2) of a machine tool (1000), The pump (32) that delivers the processing fluid, An inlet (35) through which the processing fluid sent by the pump (32) is guided to the at least one fluid consumption unit (2), A flow rate measuring device (351) is assigned to the inlet (35) and has at least one first measuring unit (351a) and one second measuring unit (351b), each configured to detect the flow rate of the processing fluid passing through the inlet (35). A hydraulic device (3) having, A control device (4) is configured to control the hydraulic system (3) based on a first measured value and / or a second measured value detected by a second measured unit (351b) of the flow rate of the processing fluid passing through the inlet (35), and in particular, the control device (4) performs control by setting the operating parameters of the pump (32) that determines the discharge capacity. A hydraulic system equipped with [the following features].

22. A machine tool (1000), and more particularly a method (1000) of processing a workpiece using a machine tool as described in any one of claims 1 to 19, A step of supplying machining fluid to the working space (1) of a machine tool (1000) via at least one fluid consumption unit (2), the step of operating a pump (32) that sends the machining fluid to at least one fluid consumption unit (2) via an inlet (35), Step (35) of detecting a first measured value of the flow rate of the processing fluid at the first point of the inlet, The steps include detecting a second measured value of the flow rate of the processing fluid at the second point of the inlet (35), A step of controlling a machine tool (1000) that processes a workpiece based on the detected first measured value and / or the detected second measured value. It has, Each of the steps described above is performed at least before and / or during machining of the workpiece (1002) placed in the workspace (1) by a tool (1001) accepted into the machine tool (1000), Method for machining the workpiece.

23. The process further includes the step of providing a set value for the flow rate of the processing fluid through at least one fluid consumption unit (2) during workpiece processing, The control of the machine tool (1000) is also performed based on the given set values. The method according to claim 22.

24. The control of the machine tool (1000) is as follows: The process further includes setting operating parameters for a pump (32) that determines the discharge capacity based on a given set value and a detected first measured value and / or second measured value. The method according to claim 23.

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