TESTING DEVICE FOR TESTING AN OBJECT ON A CLAMPING DEVICE

Description

[0001] The invention relates to a testing device for testing the abutment of an object against a clamping device. Furthermore, the invention relates to a clamping device for positioning and clamping an object with such a testing device, as well as to a machine tool with such a clamping device. The invention also relates to a method for testing the abutment of an object against a clamping device.

[0002] DE 10 2014 112 819 A1 discloses a machine tool having a work spindle with a compressed air-assisted face contact test. To determine the clamping state of a tool on a clamping device, according to one alternative embodiment, a pressure is detected at a nozzle branching off from compressed air channels. Such a face contact test is complex in design and requires high compressed air consumption.

[0003] US 2016 / 0243662 A1 discloses a machine tool comprising a clamping device with a testing device for testing the contact of an object with the clamping device. The testing device comprises a measuring chamber, an inflow resistor, an outflow resistor, and a pressure sensor for detecting the pressure in the measuring chamber. A disadvantage is that filling the measuring chamber with test fluid, in particular establishing a steady flow state required for the contact test, and thus also the contact test itself, is very time-consuming.

[0004] Such testing devices are also known from JP 2017-007027 A and JP 2006-055975 A. A measuring device for pneumatically measuring distances is known from DE 42 32 630 A1. A testing device for testing the position of an object on a clamping device is known from US 2016 / 0243662 A1. A distance measuring device is known from DE 10 2006 001 740 A1. A pneumatic support control device is known from DE 10 2008 006 778 A1.

[0005] The invention is based on the object of creating a simple testing device for testing the attachment of an object to a clamping device, which can be operated efficiently and reliably.

[0006] This object is achieved by a testing device having the features of claim 1. According to the invention, it was recognized that the testing device must have at least one outflow resistor for limiting the outflow of the test fluid from the measuring chamber and the inflow resistor for limiting the inflow of the test fluid into the measuring chamber in order to ensure particularly low compressed air consumption. Because the pressure sensor is designed and arranged in such a way that it detects the pressure of the test fluid in the measuring chamber, the testing device is particularly robust and reliable in operation. The design of the measuring chamber with the bypass opening for supplying the test fluid from the pressure source ensures that the testing device operates in a particularly time-efficient manner. In particular, the measuring chamber can be filled particularly quickly via the bypass opening, which means that the time required for system testing can be particularly short.Limiting the inflow and / or outflow of the test fluid means that the volume flow of the test fluid is reduced but not completely interrupted. The at least one outflow opening ensures the continuous drainage of the test fluid from the measuring chamber to the pressure sink, particularly when measuring the pressure. This advantageously ensures that the pressure in the measuring chamber can be measured continuously, rather than exclusively within a specific time window of a measuring cycle. This allows the system testing to be carried out in a particularly time-efficient manner. Furthermore, the pressure of the test fluid can be measured over a specific period of time to avoid measurement errors, allowing the system status of the tool to be determined particularly reliably. In particular, the function of the testing device is largely independent of leakage, especially in the area of ​​the measuring chamber. The testing device is particularly resistant to interference.The inflow resistance allows the inflow required for system testing to be significantly reduced. The compressed air consumption of the test system is thus particularly low, allowing energy-efficient operation. Furthermore, no inflow valve is required. Time-consuming switching of the test system by operating the inflow valve is eliminated.

[0007] Preferably, a bypass line for connecting the bypass opening to the pressure source is designed to be free of flow resistance. This means that the bypass line has a flow resistance that is significantly lower, in particular at least ten times, in particular at least one hundred times, in particular at least five hundred times, in particular at least one thousand times, than the inflow resistance.

[0008] According to one aspect of the invention, a cross-sectional area of ​​the bypass opening and / or the bypass line, in particular a mean cross-sectional area over the entire length of the bypass line, is at least twice, in particular at least four times, in particular at least five times, in particular at least ten times, as large as a cross-sectional area of ​​the inflow opening and / or the inflow resistance and / or the outflow resistance. Preferably, the bypass line fluidically connects the measuring chamber to the pressure source, to which the inflow opening for supplying the test fluid is also connected.

[0009] The object can be a tool or a workpiece. The clamping device is preferably designed for reversible clamping to the object. The object can have a flat contact surface for at least partially closing the at least one inspection opening.

[0010] The measuring chamber can be defined by a test housing. The measuring chamber is preferably designed in the form of at least one fluid line. The measuring chamber can also have a pressure reservoir. In particular, the measuring chamber can be designed in the form of fluid lines extending between the inflow opening, the at least one outflow opening, and the test opening. The test device can thus be manufactured particularly economically.

[0011] The inflow resistance and / or the at least one outflow resistance is understood to mean a flow resistance that is significantly, in particular at least ten times, in particular at least one hundred times, in particular at least five hundred times, in particular at least one thousand times, higher than a flow resistance of the measuring chamber and / or the fluid lines, in particular the fluid lines for connecting the inflow opening to the pressure source and / or for connecting the at least one outflow opening to the pressure sink. The inflow resistance and / or the outflow resistance can be designed as a tapered cross-section relative to the at least one fluid line and / or as a grid, in particular as a throttle valve.

[0012] The pressure sink is preferably formed by the environment of the test device. The pressure in the pressure sink preferably corresponds to the ambient pressure.

[0013] The test fluid preferably comprises a gas, in particular compressed air, and / or a liquid, in particular water and / or a coolant and / or a lubricant and / or an emulsion and / or glycol. The pressure source can be a central compressed air supply. The test fluid consisting of compressed air is particularly easy to handle.

[0014] According to a further aspect of the invention, the testing device comprises the pressure source. In particular, the testing device can comprise a pump, in particular a compressor, for providing the pressure to the pressure source. The testing device is thus independent of additional peripheral components.

[0015] Preferably, a fluid line for connecting the inflow opening to the pressure source is designed to be uninterrupted, in particular without a shut-off valve. Preferably, a fluid line for connecting the at least one outflow opening to the pressure sink is designed to be uninterrupted, in particular without a shut-off valve. The testing device can thus be manufactured particularly economically.

[0016] The flow of test fluid into the measuring chamber can be completely interrupted by means of an inlet valve. The inlet valve can have an inlet valve drive for automatically moving the inlet valve between an open and a closed position. This advantageously ensures that the test device only requires compressed air during the system test. The test device can thus be operated particularly economically.

[0017] A test device according to claim 2 ensures particularly reliable system testing. By arranging an inflow pressure sensor upstream of the inflow resistance, pressure fluctuations of the inflowing test fluid or the pressure source can be detected. Knowledge of these pressure fluctuations makes it possible to take them into account during system testing.

[0018] A testing device according to claim 3 is particularly flexible in its use. The clamping housing can be mounted so as to be rotatable relative to the base housing about at least one, in particular at least two, in particular three, axes and / or displaceable along at least one, in particular at least two, in particular at least three, axes. The clamping housing can be designed as a rotatable head of a tool spindle. The base housing can accordingly be designed as a fixed part of the tool spindle.

[0019] The test device can have at least one contact seal for reversibly sealing the bearing gap between the base housing and the clamping housing. The contact seal is preferably actuated by the test fluid. The contact seal preferably has a closed position, in which it makes sealing contact with both the base housing and the clamping housing, and an open position, in which it is arranged without contact with the base housing and / or the clamping housing. The test device is thus particularly wear-resistant.

[0020] A testing device according to claim 4 can be manufactured economically and operated with particularly high reliability. Preferably, the outflow resistance of the at least one outflow opening formed between the housing and the clamping housing is formed by a bearing gap between the base housing and the clamping housing. Complete sealing of a bearing gap between the base housing and the clamping housing is therefore not required for system testing. A costly system seal can be dispensed with.

[0021] A testing device according to claim 5 can be operated in a particularly energy- and time-efficient manner. The labyrinth seal is preferably designed to seal the clamping housing from the base housing. The testing device preferably comprises at least two labyrinth seals for sealing the measuring chamber extending over the bearing gap on both sides. Because the labyrinth seal is designed to be contactless, the testing device is particularly wear-resistant. The outflow of test fluid from the measuring chamber into the pressure sink can be significantly reduced by the labyrinth seal. In particular, the labyrinth seal enables system testing while the clamping housing is being moved relative to the base housing. Downtimes can thus be avoided.

[0022] A testing device according to claim 6 is particularly reliable to operate. The at least one outflow resistor can be designed as an adjustable throttle valve, in particular one that can be actuated pneumatically and / or electrically and / or manually. In particular, the at least one outflow resistor can be designed to limit the outflow of the test fluid in a temperature-dependent manner. Because the at least one outflow resistor is adjustable, the pressure of the test fluid in the measuring chamber can be adjusted such that the pressure sensor operates within its linear measuring range. In particular, temperature fluctuations in the measuring chamber and / or pressure fluctuations of the inflowing test fluid can be compensated.

[0023] A testing device according to claim 7 can be operated particularly time-efficiently. Preferably, the bypass valve has a valve drive for moving the bypass valve between an open position and a closed position. The bypass valve can thus be moved automatically between the open position and the closed position. To fill the measuring chamber, the bypass line and / or the bypass valve can have a flow resistance that is, in particular, at least five times, in particular, at least ten times, in particular, at least twenty times, lower than the flow resistance of the measuring chamber. During the system test, the bypass valve can be closed to increase measurement accuracy.

[0024] A testing device according to claim 8 can be operated and automated particularly efficiently. To determine a test pressure of the test fluid in the measuring chamber, the control unit is in signal communication with the pressure sensor. The control unit can be designed to determine a pressure change based on the test pressure. Preferably, the control unit is designed to compare the pressure change with a pressure change limit and / or the test pressure with a test pressure limit. The control unit is preferably designed such that an incorrect positioning state is detected if the test pressure is lower than the test pressure limit. Preferably, the control unit is designed to determine the positioning state only when the pressure change is lower than the pressure change limit.This advantageously ensures that the positioning state is only determined when a largely stationary test pressure has been established in the measuring chamber.

[0025] According to a further aspect of the invention, the control unit can be designed such that the positioning state is determined based on the pressure change. In particular, the control unit can be designed to determine the positioning state before a steady state of the pressure value is reached. For this purpose, the control unit can compare the pressure change value with a target pressure change value and / or a pressure change profile, in particular a temporal one, with a target pressure change profile. Preferably, an incorrect positioning of the object is determined if the pressure change value is less than the target pressure change value and / or if the pressure change profile exceeds a predetermined limit deviation from a target pressure change profile. The control unit can also be designed to determine a time coefficient of the pressure change for determining the positioning state. The positioning state can thus be determined in a particularly time-saving manner.

[0026] According to one aspect of the invention, the control unit is in signal communication with the inflow pressure sensor and / or a temperature sensor and / or a motion sensor. The temperature sensor is preferably designed to detect a temperature of the test fluid in the measuring chamber. The motion sensor can be designed as a rotation sensor for detecting a rotational movement of the clamping housing relative to the base housing. The control unit can be designed to determine the positioning state based on a signal from the inflow pressure sensor and / or the temperature sensor and / or the motion sensor. In particular, the control unit can use the rotational movement to determine the movement-dependent outflow resistance of the labyrinth seal. The positioning state can thus be determined particularly reliably.

[0027] A testing device according to claim 9 can be operated and automated in a particularly energy-efficient manner. The inflow valve can be designed to completely close off the inflow of the test fluid. Because the control unit is in signal communication with the inflow valve, the need for compressed air can be limited to the period of the system test. In particular, the control unit can be designed to adjust the outflow resistance and / or the inflow resistance depending on a signal from the temperature sensor and / or the motion sensor. The pressure sensor can thus be operated within its linear measuring range, allowing the system test to be carried out particularly reliably and precisely.

[0028] The invention is further based on the object of creating a clamping device for positioning and clamping the object, which can be operated in a particularly energy-efficient and time-efficient manner.

[0029] This object is achieved by a clamping device with the features of claim 10. The advantages of the clamping device according to the invention correspond to the advantages of the testing device described above. The contact body for clamping with the object can be formed by the clamping housing. According to one aspect of the invention, the clamping device has at least one clamping element for effecting a clamping force between the object and the contact body. The test opening can be formed in the contact body as a bore and / or as a groove, in particular an annular one. The contact body can have a sealing element. Preferably, the sealing element is designed such that, when the object lies correctly against the clamping device, it interacts with the object to form a seal to completely close the test opening.

[0030] The invention is also based on the object of creating an improved machine tool.

[0031] This object is achieved by a machine tool having the features of claim 11. The advantages of the machine tool according to the invention correspond to the advantages of the clamping device described above and the testing device described above. The machine tool can be designed as a multi-axis machine. The drive device can be designed for the rotational and / or translational displacement of the drive body relative to the machine frame. Preferably, the drive device is designed such that the contact body can be displaced relative to the machine frame about at least one, in particular at least two, in particular at least three axes of rotation and / or along at least one, in particular at least two, in particular at least three displacement directions. The drive device can comprise a spindle drive for the rotational displacement of the contact body relative to the machine frame.According to one aspect of the invention, the machine tool has a machine control system for controlling the machine tool. This advantageously ensures that operation of the machine tool can be started or interrupted depending on the positioning state.

[0032] The invention is further based on the object of creating a method for testing the positioning of an object on a clamping device, which can be carried out in a particularly energy-efficient and time-efficient manner and reliably enables detection of an incorrect positioning state.

[0033] This object is achieved by a method having the features of claim 12. The advantages of the method according to the invention correspond to the advantages of the machine tool, the clamping device, and the testing device described above. Preferably, the positioning state is determined based on a signal from the inflow pressure sensor and / or the temperature sensor and / or the motion sensor. The outflow resistance is preferably adjusted based on a signal from the inflow pressure sensor and / or the temperature sensor and / or the motion sensor.

[0034] According to one aspect of the invention, the operation of the machine tool, in particular of the drive device, is started and / or interrupted and / or limited depending on the positioning state.

[0035] A method according to claim 13 is particularly time-efficient and flexible to implement. In particular, the displacement of the at least one test opening relative to the inflow opening comprises a rotational movement. Preferably, the contact test is performed while the at least one test opening is being displaced relative to the inflow opening. Downtimes for checking the contact of the object with the clamping device can thus be avoided.

[0036] A method according to claim 14 ensures a particularly reliable test of the attachment of the object to the clamping device. The measured temperature is preferably recorded as the temperature of the test fluid in the measuring chamber. Since the recorded pressure can vary depending on the measured temperature and / or the relative movement, taking the measured temperature and / or the relative movement into account during the attachment test leads to a particularly reliable test result.

[0037] A method according to claim 15 ensures system testing in a particularly reliable manner. By adjusting the outflow resistance depending on the measuring temperature and / or the relative movement, disruptive influences on the pressure of the test fluid in the measuring chamber can be reduced.

[0038] A method according to claim 16 can be carried out particularly time-efficiently. Preferably, the test fluid is fed into the measuring chamber via the inflow opening and additionally via a bypass opening separate from the inflow opening and / or the outflow opening. By additionally filling the measuring chamber via the bypass opening, the pressure in the measuring chamber required for the system test can be reached particularly quickly. The bypass line connected to the bypass opening is preferably closed after the measuring chamber has been filled. This ensures that the pressure in the measuring chamber reacts particularly sensitively to an outflow of the test fluid via the test opening. The pressure is recorded accordingly when the bypass line is closed.

[0039] A method according to claim 17 can be carried out particularly time-efficiently. By determining the positioning state during the pressure change in the measuring chamber, a waiting time during the filling of the measuring chamber with the test fluid until a largely stationary pressure is formed can be avoided. To determine the positioning state, a pressure change and / or a pressure curve and / or a time coefficient of the pressure change can be determined. In particular, an ensuing convergence pressure value can be calculated in advance based on the pressure curve. By avoiding waiting times, the system test can be carried out particularly time-savingly and the machine tool can be operated particularly efficiently.

[0040] Further features, advantages, and details of the invention will become apparent from the following description of an exemplary embodiment. It shows: Fig. 1 a schematic representation of a machine tool with a machine frame, a clamping device and a drive device for displacing a contact body of the clamping device relative to the machine frame and Fig. 2 a schematic representation of the clamping device in Fig. 1 , wherein the clamping device has the contact body for clamping with an object and a testing device, and wherein a testing opening of the testing device arranged on the contact body is completely closed by the object.

[0041] In the Fig. 1 A machine tool 1 with a machine frame 2 and a clamping device 3 is shown. The clamping device 3 is designed for positioning and clamping an object 4. For clamping to the object 4, the clamping device 3 has a contact body 5.

[0042] The machine tool 1 comprises a drive device 6 for displacing the support body 5 relative to the machine frame 2. For rotating the object 4, the drive device 6 comprises a spindle drive 7. By means of the spindle drive 7, the object 4 can be displaced about a rotational axis 8. The drive device 6 has a linear drive 9 for displacing the support body 5 relative to the machine frame 2. The machine tool 1 is designed to machine a workpiece 10 using the object 4.

[0043] In the Fig. 2the clamping device 3 is shown in further detail. The clamping device 3 is designed for positioning and clamping the object 4. The clamping device 3 comprises a testing device 11 for testing the contact surface of the object 4 and the clamping device 3. In order to provide a clamping force acting between the object 4 and the contact body 5, the clamping device 3 has a plurality of clamping elements 12. The clamping elements 12 are arranged on the contact body 5 so as to be displaceable in the radial direction to the axis of rotation 8. The clamping elements 12 each interact with the object 4 via a clamping surface 13. The clamping surface 13 is designed to exert a clamping force acting along the axis of rotation 8 on the object 4 due to a radial displacement to the axis of rotation 8.

[0044] The testing device 11 has a measuring chamber 14. The measuring chamber 14 comprises two inflow openings 15a, 15b for supplying a test fluid from a pressure source 16. The pressure source 16 is designed as a compressed air source. Furthermore, the measuring chamber 14 comprises two outflow openings 17a, 17b for discharging the test fluid to a pressure sink 18. The pressure sink 18 is formed by an environment of the testing device 11, in particular by an interior of the machine frame 2. The measuring chamber 14 further comprises a test opening 19, which is arranged on the contact body 5. The test opening 19 can be at least partially closed by the object 4 resting against the contact body 5.

[0045] The test device 11 has fluid lines 20 for conducting compressed air. The measuring chamber 14 is formed by the fluid lines 20 arranged between the inlet openings 15a, 15b, the outlet openings 17a, 17b, and the test opening 19.

[0046] The first inflow opening 15a is arranged on a test line 21. An inflow resistor 22 is arranged between the first inflow opening 15a and the pressure source 16, in particular on the test line 21. The inflow resistor 22 is designed to limit the inflow of the test fluid via the inflow opening 15a. The inflow resistor 22 is designed as an adjustable throttle valve.

[0047] The first outflow opening 17a is fluidically connected to the pressure sink 18 via a reducing line 23. To limit the outflow of the test fluid through the first outflow opening 17a, a first outflow resistor 24a is arranged between the first outflow opening 17a and the pressure sink 18. The first outflow resistor 24a is adjustable. In particular, the first outflow resistor 24a is designed as an adjustable throttle valve.

[0048] The second outflow opening 17b is in fluid communication with the pressure sink 18 via a second outflow resistor 24b. The second outflow resistor 24b is designed as a labyrinth seal 25.

[0049] The labyrinth seal 25 is arranged between a base housing 26 and a clamping housing 27. The clamping housing 27 is connected in a rotationally fixed manner to the contact body 5. In particular, the contact body 5 is formed by the clamping housing 27. The base housing 26 is connected in a rotationally fixed manner to the machine frame 2.

[0050] The measuring chamber 14 spans a bearing gap 28 between the base housing 26 and the clamping housing 27. The labyrinth seal 25 is designed to seal the measuring chamber 14 in the region of the bearing gap 28 against the pressure sink 18, in particular the environment.

[0051] The test device 11 has a pressure sensor 30, which is fluidically connected to the measuring chamber 14. Furthermore, the test device 11 includes an inflow pressure sensor 31 for detecting a pressure of the test fluid upstream of the inflow resistor 22. The inflow pressure sensor 31 is arranged upstream of the inflow resistor 22 on the test line 21.

[0052] The testing device 11 has a temperature sensor 32 for detecting the temperature of the test fluid in the measuring chamber 14. A rotation sensor 33 is arranged on the spindle drive 7 for detecting a rotational movement, in particular a rotational speed, of the contact body 5 relative to the machine frame 2.

[0053] The second inflow opening 15b is fluidly connected to the pressure source 16 via a bypass line 34. The second inflow opening 15b is also referred to as a bypass opening. A bypass valve 35 is arranged on the bypass line 34 for reversibly closing it. The bypass valve 35 has a valve drive 36 for automatically switching the bypass valve 35 between an open position and a closed position.

[0054] The testing device 11 has a control unit 37. The control unit 37 is in signal communication with the pressure sensor 30, the inflow pressure sensor 31, the temperature sensor 32, and the rotation sensor 33. Furthermore, the control unit 37 is in signal communication with the first outflow resistor 24a, the inflow resistor 22, and the valve drive 36. The control unit 37 is designed to determine a positioning state of the object 4 on the contact body 5 based on a signal from the pressure sensor 30. Furthermore, the control unit 37 is designed to determine the positioning state based on a rotational movement detected by the rotation sensor 33, a temperature determined by the temperature sensor 32, and a pressure detected by the inflow pressure sensor 31. To move the bypass valve 35 between the open position and the closed position, the control unit 37 is in signal communication with the valve drive 36.Furthermore, the control unit 37 is designed to adjust the inflow resistance 22 and the first outflow resistance 24a based on the pressure detected by the pressure sensor 30.

[0055] The test device 11 has an inflow valve 38 for reversibly shutting off the inflow of the test fluid from the pressure source 16. The inflow valve 38 comprises an inflow valve drive 39. The inflow valve drive 39 is in signal communication with the control unit 37.

[0056] The operation of the machine tool 1 or the clamping device 3 or the testing device 11 for testing the attachment of the object 4 to the clamping device 3 is as follows: The machine tool 1 is in a home position. The clamping device 3 is attached to the machine frame 2, with the test opening 19 open to an interior of the machine frame 2. The spindle drive 7 is deactivated. The bypass valve 35 is in the closed position. The test opening 19 is connected to the pressure source 16 via the measuring chamber 14, the first inflow opening 15a, the inflow resistor 22, and the inflow valve 38. The inflow valve 38 is in a closed position.

[0057] By means of a signal from the control device 37, the inflow valve drive 39 is activated, and the inflow valve 38 is moved from the closed position to the open position. Limited by the inflow resistor 22, test fluid in the form of compressed air continuously flows into the measuring chamber 14 and out of it via the test opening 19 into the pressure sink 18 formed by the interior of the machine frame 2. Compressed air flows from the measuring chamber 14 to the pressure sink 18 via the labyrinth seal 25 and the second outflow resistor 24a.

[0058] The pressure sensor 30 and the inflow pressure sensor 31 each measure the pressure of the test fluid. The inflow resistance 22 is adjusted by the control unit 37 such that the pressure applied to the pressure sensor 30 lies within the linear measuring range of the pressure sensor 30. During the test procedure described below, the inflow resistance 22 is adjusted by the control unit 37 based on a signal from the inflow pressure sensor 31 such that low-frequency pressure fluctuations of the inflowing test fluid are compensated.

[0059] The pressure in the measuring chamber 14 is lower than the pressure in the pressure source 16 and higher than a pressure prevailing in the pressure sink 18.

[0060] The object 4 is connected to the clamping device 3. For this purpose, the object 4 is brought towards the contact body 5. The clamping elements 12 are brought towards the workpiece 4 in the radial direction to the rotation axis 8, whereby the object 4 is clamped to the contact body 5 along the rotation axis 8. In a first positioning state, the object 4 rests completely and flawlessly against the contact body 5. The object 4 completely closes the test opening 19. A pressure increase at the pressure sensor 30 is determined by means of the control unit 37. The control unit 37 provides a signal to open the bypass valve 35 to the valve drive 36. The bypass valve 35 is opened. The test fluid flows into the measuring chamber 14 via the bypass valve 35 and the second bypass opening 15b. A fluid flow fed into the measuring chamber 14 via the bypass opening 15b is greater than a fluid flow fed into the measuring chamber 14 via the inflow opening 15a.The measuring chamber 14 can be filled with the test fluid particularly quickly via the bypass line 34.

[0061] The control unit 37 compares a test pressure applied to the pressure sensor 30 with a filling pressure limit. As soon as the test pressure exceeds the filling pressure limit, the control unit 37 sends a signal to the valve drive 36 to close the bypass valve 35. The valve drive 36 moves the bypass valve from the open position to the closed position.

[0062] The control unit 37 determines a pressure change at the pressure sensor 30. The control unit 37 compares the pressure change with a pressure change threshold. As soon as the pressure change falls below the pressure change threshold, the test pressure required for the system test is measured in the measuring chamber 14 using the pressure sensor 30.

[0063] The control unit 37 compares the test pressure with a test pressure limit. A positioning state of the object 4 on the clamping device 3 is determined depending on a difference between the test pressure and the test pressure limit. Since the object 4 is correctly positioned against the support body 5, the test pressure is higher than the test pressure limit. The control unit 37 detects the correct positioning of the object 4 on the clamping device 3. The control unit 37 provides a signal to a machine control system (not shown) of the machine tool 1, which signal correlates with the correct positioning state. The spindle drive 7 is activated, and the workpiece 10 is machined using the object 4.

[0064] During the machining of workpieces 10, the clamping device 3 is exposed to contaminants. Contaminants, in particular material removed from the workpiece 10, can reach the contact body 5. For example, a chip can get between the contact body 5 and the object 4. The object 4 is then incorrectly positioned on the clamping device 3. Alternatively, it is possible that the clamping elements 12 cannot provide the required contact force between the object 4 and the contact body 5 due to a malfunction. The object 4 can then shift into an incorrect second positioning state during clamping.

[0065] The faulty positioning state results in the test opening 19 not being completely closed by the object 4. Because the test fluid can also flow out of the measuring chamber 14 via the test opening 19, the pressure of the test fluid in the measuring chamber 14 is reduced. In particular, the test pressure is lower in the faulty positioning state than in the fault-free positioning state.

[0066] The test pressure is then determined by the control unit 37 when the pressure change falls below the pressure change limit. The test pressure is compared with the test limit pressure. Since the resulting test pressure is lower than the test pressure limit due to the leak between the object 4 and the system body 5, the faulty positioning state is detected. The control unit 37 provides a signal to the machine control system that correlates with the faulty positioning state. The start-up of the machine tool, in particular the machining of the workpiece 10, is blocked. An alarm signal is output to a user via the machine control system.

[0067] Because the bearing gap 28 between the base housing 26 and the clamping housing 27 is sealed by the labyrinth seal 25, the positioning state can be determined during the displacement of the support body 5 relative to the machine frame 2, i.e., during operation of the machine tool 1. In particular, the positioning state can be determined during the displacement of the test opening 19 relative to the inlet opening 15a. The second outflow resistance 24b of the labyrinth seal 25 depends on a movement of the clamping housing 27 relative to the base housing 26. This relative movement is detected by the rotation sensor 33. The first outflow resistance 24a is adjusted by the control unit 37 based on the signal from the rotation sensor 33.The first outflow resistance 24a is adjusted such that a total outflow resistance between the measuring chamber 14 and the pressure sink 18, across the first outflow resistance 24a and the second outflow resistance 24b, remains constant.

[0068] The control unit 37 determines the positioning state taking into account the temperature of the test fluid in the measuring chamber 14, as detected by the temperature sensor 32. In particular, the first outflow resistance 24a is adjusted based on the temperature in the measuring chamber 14. The properties of the test fluid, which change with temperature, are taken into account when determining the positioning state by the control unit 37.

[0069] By forming the measuring chamber 14 with the inflow opening and at least one outflow opening, wherein the inflow resistor 22 is provided to limit the inflow of the test fluid and the outflow resistors 24a, 24b are provided to limit the outflow of the test fluid, the contact test of the object 4 against the clamping device 3 can be carried out particularly reliably and energy-efficiently. Because the second outflow resistor 24b is designed as a labyrinth seal 25, a cost-intensive, wear-prone, and time-consuming contact seal can be dispensed with. The adjustable inflow resistor 22 enables the compensation of pressure fluctuations. The bypass line 34, together with the bypass valve 35, ensures a particularly time-efficient contact test of the workpiece 4 against the clamping device 3.

Claims

1. Test equipment for testing the seating of an object on a clamping device, having - a measurement chamber (14) with -- an inflow opening (15a) for supplying a test fluid from a pressure source (16), and -- at least one test opening (19), which can be at least partially closed by the object (4) resting against the clamping device (3), - an inflow resistance (22) for limiting an inflow of the test fluid via the inflow opening (15a), and - a pressure sensor (30) for detecting a pressure of the test fluid in the measurement chamber (14), wherein the measurement chamber (14) has a bypass opening (15b) for supplying the test fluid from the pressure source (16), characterised in that the measurement chamber has at least one outflow opening (17a, 17b) for discharging the test fluid to a pressure sink (18), wherein the test equipment has at least one outflow resistance (24a, 24b) for limiting an outflow of the test fluid via the at least one outflow opening (17a, 17b).

2. Test equipment according to Claim 1, characterised by an inflow pressure sensor (31) arranged upstream of the inflow resistance (22).

3. Test equipment according to Claim 1 or 2, characterised in that the measurement chamber (13) is formed by a base housing (26) and a clamping housing (27) that can be moved relative to the base housing (26), wherein the inflow opening (15a) is arranged on the base housing (26) and wherein the test opening (19) is arranged on the clamping housing (27).

4. Test equipment according to Claim 3, characterised in that the at least one outflow opening (17a, 17b) is formed between the base housing (26) and the clamping housing (27).

5. Test equipment according to Claim 3 or 4, characterised in that the at least one outflow resistance (24a, 24b) is configured as a labyrinth seal (25) between the base housing (26) and the clamping housing (27).

6. Test equipment according to one of the preceding claims, characterised in that the at least one outflow resistance (24a, 24b) can be adjusted.

7. Test equipment according to one of the preceding claims, characterised by a bypass valve (35) for reversibly interrupting an inflow of the test fluid via the bypass opening (15b).

8. Test equipment according to one of the preceding claims, characterised by a control unit (37), which is in signal communication with the pressure sensor (30) for determining a positioning state of the object (4) on the clamping device.

9. Test equipment according to Claim 8, characterised in that the control unit (37) is in signal communication the inflow resistance (22) and / or at least one outflow resistance (24a, 24b) and / or a bypass valve (35) and / or an inflow valve (38) for controlling same.

10. Clamping device for positioning and clamping an object with - a piece of test equipment (11) according to one of Claims 1 to 9 and - a seating body (5) for clamping with the object (4), - wherein the at least one test opening (19) is arranged on the seating body (5).

11. Machine tool, with - a machine frame (2), - a clamping device (3) according to Claim 10 and - a drive device (6) for moving the seating body (5) relative to the machine frame (2).

12. Method for testing the seating of an object on a clamping device, comprising the steps: - providing a piece of test equipment (11) according to one of Claims 1 to 9, - detecting the pressure of the test fluid in the measurement chamber (14) by means of the pressure sensor (30), wherein the pressure fluid continuously flows out of the measurement chamber (14) via the at least one outflow opening (17a, 17b) when the pressure is being detected, and - determining a positioning state based on the pressure.

13. Method according to Claim 12, characterised by moving the at least one test opening (19) relative to the inflow opening (15a) when the pressure is being detected.

14. Method according to Claim 12 or 13, characterised by determining the positioning state as a function of a measurement temperature and / or a relative movement between the test opening (19) and the inflow opening (15a).

15. Method according to one of Claims 12 to 14, characterised by adjusting the at least one outflow resistance (24a, 24b) as a function of a measurement temperature and / or a relative movement between the test opening (19) and the inflow opening (15a).

16. Method according to one of Claims 12 to 15, characterised by filling the measurement chamber with the test fluid via a bypass line (34), closing the bypass line (34) and detecting the pressure with the bypass line (34) closed.

17. Method according to one of Claims 12 to 16, characterised in that determining of the positioning state is determined during a pressure change in the measurement chamber (14).