EP3580000A1

EP3580000A1 - Method and device for actuating a hydraulic expansion chuck device

Info

Publication number: EP3580000A1
Application number: EP18705851.6A
Authority: EP
Inventors: Thomas Retzbach
Original assignee: Schunk GmbH and Co KG
Current assignee: Schunk GmbH and Co KG
Priority date: 2017-02-07
Filing date: 2018-02-06
Publication date: 2019-12-18
Also published as: JP7109456B2; DE102017114536B3; WO2018146092A1; JP2020506076A

Abstract

The invention relates to a method for actuating a hydraulic expansion chuck device (3) having a main-body arrangement (4) in which a pressure-chamber system which is fillable with hydraulic medium is formed, said pressure-chamber system comprising a pressure chamber (15) having a wall (18), which defines a clamping face (19) on a side facing away from the pressure chamber (15), and a threaded bore (8) that has been introduced into the main-body arrangement (4) from the outside and is connected to the pressure chamber (15) via connecting ducts, wherein a clamping bolt (9) has been screwed into the threaded bore (8), said clamping bolt (9) being axially adjusted as a result of being screwed into the threaded bore (8), such that the hydraulic medium is pushed in the direction of the pressure chamber (15) and the wall (18) is elastically deformed in order to clamp a tool (20) or workpiece, wherein, in the method, the clamping bolt (9) is turned by means of a turning tool (22), the torque applied to the hydraulic expansion chuck device (3) is supported in particular by the hydraulic expansion chuck device (3) being fixed in a stationary holder (2), values indicating the hydraulic-medium pressure are measured by means of a measuring device (23) at predefined, equal measuring intervals and/or continuously during the turning of the clamping bolt (9), a clamped state of the hydraulic expansion chuck device (3) is determined by evaluating the measured values indicating the hydraulic-medium pressure by means of an evaluation and control device (25), and the determined clamped state of the hydraulic expansion chuck device (3) is signalled to a user by means of a signalling device (26). The invention also relates to a device (1) for actuating a hydraulic expansion chuck device (3).

Description

DESCRIPTION

Method and device for actuating a hydraulic expansion device

The present invention relates to a method for actuating a hydraulic expansion chuck, in particular a hydraulic expansion chuck or hydro-expansion mandrel, comprising a main body assembly in which a filled with a hydraulic medium pressure chamber system is formed, which has a pressure chamber with a wall on one of the pressure chamber side facing away from a clamping surface defined, and introduced from the outside into the main body assembly and connected via connecting channels with the pressure chamber threaded bore, wherein in the threaded bore a clamping screw is screwed, which is axially adjusted by screwing into the threaded bore such that the hydraulic medium in the direction pressed the pressure chamber and the wall is elastically deformed to clamp a tool or workpiece, wherein in the method, the clamping screw rotated by means of a rotary tool and the torque applied to the hydraulic expansion device, in particular by Fix ieren the hydraulic expansion chuck is supported in a stationary support. Furthermore, the invention relates to a device for actuating a hydraulic Dehnspanneinrichtung.

Hydro-Dehnspanneinrichtungen are clamping devices that can be used for both the tool and the workpiece clamping, which is basically a distinction between two different types, namely a hydraulic expansion chuck and a hydraulic expansion mandrel. The basic mode of operation of both types of construction is identical, namely that by actuating the hydraulic expansion device, a hydraulic medium, in particular a hydraulic köl, is pressed within a pressure chamber system of a base body assembly of the hydraulic expansion device in the direction of a pressure chamber of the pressure chamber system and thereby causes an elastic expansion of a clamping surface defining a wall of the pressure chamber. Due to the widening of the wall, a joining clearance between the wall and a tool or workpiece to be clamped is first of all compensated and the wall is then pressed against the workpiece or tool to be clamped, resulting in a frictional connection between the hydraulic expansion fixture and the tool or workpiece. The only difference between the two designs lies in the clamping contour. Thus, the hydraulic expansion mandrel clamps a workpiece over a bore of the workpiece, whereas the hydraulic expansion chuck clamps a tool shank via a central tool holder of the hydraulic expansion chuck.

Actuation of hydraulic expansion jigs can be done in different ways. In order to generate sufficient for a voltage hydraulic pressure within the pressure chamber system of the hydraulic expansion device, on the one hand an operation by means of a clamping cylinder and a pressure or pull rod is possible. On the other hand, a direct application by means of a hydraulic unit can take place. Furthermore, hydraulic expansion chucks can be actuated by turning a tightening screw by means of a turning tool. In this case, it is known to support the torque applied to the hydro-expansion chuck, in particular by fixing the hydraulic expansion chuck in a stationary support. On the last enumerated type of actuation by means of clamping screw, the present invention relates.

When the hydraulic expansion chuck is a hydro-expansion chuck, the aforementioned basic body arrangement of the hydro-expansion chuck comprises a base body, which at its back The lower end region has a machine interface, via which the hydraulic expansion chuck can be fixed to a corresponding tool holder receptacle on a machine tool. On the opposite side of the base body, a clamping region is formed with a central tool receptacle which is open towards the front end face of the main body and into which a tool shank to be clamped can be inserted. In some hydraulic expansion chucks, the base body assembly also includes an expansion sleeve which is inserted into the base body to form a pressure chamber surrounding the expansion sleeve and acted upon by a hydraulic medium and which forms the tool holder open towards the front end surface of the base body.

When used in the industry, hydraulic expansion equipment is subject to wear and tear, so regular checking of the condition and performance of the hydraulic expansion equipment is important to ensure process reliability and avoid production downtime due to unintentional release of tools or workpieces. By a clamping force measurement, the remaining performance and wear can be determined.

The previously known methods and devices for actuating a hydraulic expansion chuck do not make it possible to determine the clamping state or the performance of the hydraulic expansion chuck during a rotation of the clamping screw, that is to say during operation of the hydraulic expansion chuck. Measurements of the clamping force for the assessment of a clamping state of a hydraulic expansion chuck have always had to be done separately by means of additional measuring devices and measurement setups. For clamping force measurement, torque wrenches, measuring mandrels or special tension force testers for hydro-expansion chucks can be used in a known manner. A disadvantage in particular A measuring mandrel or clamping force tester is such that it can not be used to determine the quality of a clamping of a tool or workpiece with a hydraulic expansion-clamping device during its operation, but the measurement must be carried out in a separate step. This is awkward and time consuming.

Against this background, the object of the present invention is to specify a method and a device for actuating a hydraulic expansion-tensioning device of the type mentioned above, in which a current tensioning state of the hydraulic expansion-tensioning device can be determined during the twisting of a tensioning screw. In addition, a corresponding device for actuating a hydraulic Dehnspanneinrichtung be specified.

This object is achieved according to the invention in a method for actuating a hydraulic expansion chuck device of the type mentioned above in that the method comprises the following steps:

a) measuring hydraulic pressure indicative values by means of a measuring device at predetermined, uniform measuring distances and / or continuously during the rotation of the clamping screw,

b) determining a clamping state of the hydraulic expansion chuck device by evaluating the measured hydraulic medium pressure indication values by means of an evaluation and control device and

c) signaling the determined clamping state of the hydraulic expansion chuck means of a signaling device to a user.

The invention is thus based on the consideration of determining a clamping state of the hydraulic expansion chuck device by indirectly determining the current clamping force values of the hydraulic expansion chuck device via a measurement of hydraulic expansion devices. Likmediumdruck- lndikationswerte during a rotation of the clamping screw, so during the clamping of the hydraulic expansion chuck, measured and evaluated the measured values are evaluated. A corresponding evaluation of the detected measured values allows a conclusion on the performance and / or the wear and / or possible malfunction of the hydraulic expansion chuck and thus the derivation of a current clamping state of the hydraulic expansion chuck. The determined in this way clamping state of the existing of the hydraulic Dehnspanneinrichtung and a tensioned tool or workpiece total system is communicated to the user immediately, comfortably and easily understandable. For example, the user is signaled when a minimum clamping force or a set clamping force of the hydraulic expansion chuck has been reached without the user having to intervene in the overall system from the outside and have to make inquiries of himself.

According to one embodiment of the invention, the turning tool is automatically aligned relative to the hydro-Dehnspanneinrichtung and automatically brought into engagement with the clamping screw. As a result, a consistent quality of intervention can be ensured.

After a successful engagement, the clamping screw can be automatically rotated by means of a screwing, in particular an electric screwing device on which the rotary tool is held. For example, the electric screwdriver is an electric screwdriver and the rotary tool is a hexagon bit which is rotatably supported on the cordless screwdriver. Electric screwing devices have the particular advantage that with them a constant screwing speed of the clamping screw can be achieved. Alternatively, the clamping screw can be manually rotated by means of the turning tool, in particular a screwdriver. In step a), values of the pressure of the hydraulic medium as hydraulic medium pressure indication values in the pressure chamber system and / or on the tensioning screw can be measured via a pressure transducer during a screwing-in of the tensioning screw. In this case, therefore, a direct measurement of the pressure takes place. In some hydrau-Dehnspanneinrichtungen adjacent to the threaded bore of the pressure chamber system in the axial direction of a cylinder bore of the pressure chamber system, in which there is a clamping piston, which contacts the clamping screw or is connected thereto, so that an axial adjustment of the clamping screw when screwing in the threaded bore causes an axial adjustment of the clamping piston. An advantage of a clamping piston is that the clamping screw can be unscrewed completely and without negative consequences from the threaded hole when releasing a tension, as the clamping piston is always located within the associated cylinder bore and the pressure chamber system thus always remains completed. In the case of a hydraulic expansion chuck with a tensioning piston, during a screwing in of the tensioning screw, values of the pressure of the hydraulic medium can be measured as hydraulic medium pressure indication values on the tensioning piston instead of on the tensioning screw via a pressure transducer. By directly measuring the pressure of the hydraulic medium, a possible conversion of hydraulic medium pressure indication values into pressure values is dispensed with.

Additionally or alternatively, values of a variable complementary to the pressure of the hydraulic medium can be measured as hydraulic medium pressure indication values in step a) during a screwing in of the tensioning screw. In this case, the pressure of the hydraulic medium is not measured directly, but indirectly over another size. There is no need to change be performed on the pressure chamber system, such as an installation of pressure transducers.

Likewise, a deformation, in particular an expansion and / or an elongation, of the basic body arrangement can be measured as a variable complementary to the pressure of the hydraulic medium as hydraulic medium pressure indication values with the aid of a strain gauge. Such a strain gauge can be attached without great effort, for example, on an outer surface of the main body assembly.

The torque on the tensioning screw is preferably measured as a variable complementary to the pressure of the hydraulic medium as hydraulic medium pressure indication values. In this case, the measurement of the torque on the clamping screw via a measurement of the torsion of a torsion by means of a mounted on the torsion strain gauge can be done. If the tightening screw is rotated by means of an electric screwing device, on which the turning tool is held, the measurement of the torque on the tightening screw can also take place via a measurement of the motor current of a motor of the electric screwing device at a constant engine speed. For the motor current I is proportional to the torque M according to the relationship M = kM x (I-lo), where lo is the idling current due to friction and kM is the torque constant which relates to the voltage constant kE via kM = 3 / TT x kE stands. A measurement of the torque of the clamping screw on the motor current is extremely elegant, since it does not require any modifications to the exciting hydraulic expansion device. It may be advantageous, during a screwing in of the clamping screw, in addition to the hydraulic pressure readings measured in step a), also clamping screw path indication values, in particular beginning with the occurrence of a predetermined trigger event or with the measurement of a predetermined trigger value in predetermined, uniform Measuring distances and / or to measure continuously. In this case, the measuring distance between two directly successively measured hydraulic medium pressure indication values preferably corresponds to the measuring distance between two directly successive measured Spannschraubeweg indicative values, in particular a predetermined path step, angle step or time step at a constant insertion speed of the clamping screw. The trigger event can be a contact of the clamping surface with a tool or workpiece to be clamped and / or a stop of the clamping screw on a limiting the axial displacement of the clamping screw stop and / or the trigger value can be a for the used Hydro-Dehnspanneinrichtung in a certain trigger event be characteristic value of the pressure of the hydraulic medium or a complementary size. The trigger value may also be a threshold value of the pressure of the hydraulic medium or a complementary quantity which is preferably between 20% (in a hard screwing) and 80% (in a soft screwing) of a value of the pressure or a variable complementary thereto, in which a tightening of the clamping screw is terminated, that is, for example, a Abschaltdrehmomentwerteswert when reaching the stop by the clamping screw. The measured tension screw path indicative values may be used to ascertain whether a tension state determined based on the measured hydraulic fluid pressure indication values is correct. Values of the axial travel position of the tightening screw within the threaded hole can be measured as tightening screw path indication values. In this case, the Spannschraubenweg is measured directly. Thus, a possible conversion of Spannschraubenweg-Indikationswerten in Spannschraubenwege deleted.

Additionally or alternatively, values of a variable complementary to an axial path position of the tightening screw within the threaded bore can be measured as tightening screw path indication values. In this case, the tightening screw travel is measured indirectly by measuring another variable. Advantageously, the angle of rotation of the clamping screw as a complementary to the axial path position of the clamping screw within the threaded bore size as Spannschraubenweg indicative values, preferably by means of an encoder and / or Hall sensors, either directly on the clamping screw or on the rotary tool or on a screw device, at which the rotary tool is held, measured. In the case of an electric screw device with an electric motor Hall sensors can be used to determine a rotor position of the motor. Particularly advantageous are brushless DC motors (BLDC). Because with such motors position signals are required for an electronic commutation, which is why the position of the rotor is known in BLDC motors. A measurement of the angle of rotation via an encoder or Hall sensors on the clamping screw is particularly elegant because it does not require any modifications to the exciting hydraulic expansion device. Such a rotational angle measurement therefore contributes to the fact that clamping states can be determined for a wide variety of hydraulic expansion chucks during their actuation. Using the measured angle of rotation and a known pitch of the thread of the clamping screw, the distance covered by the clamping screw and, if appropriate, the tensioning piston can then be calculated. At a constant rotational speed of Clamping screw can also be the rotation time measured as a complementary to the axial path position of the clamping screw size.

In order to determine a clamping state of the hydraulic expansion clamping device in step b) by evaluating the measured hydraulic medium pressure indication values, the following partial steps are advantageously carried out in step b):

b1) checking whether a hydraulic medium pressure indication value measured during a tightening of the tightening screw is within a predefined range around a hydraulic medium pressure indication value characteristic of the hydraulic expansion chuck type used, and

b2) closing to a clamping state of the hydraulic expansion device associated with the characteristic hydraulic pressure indicative value if the test in step b1) is positive. The characteristic hydraulic pressure indicative value is preferably a characteristic hydraulic pressure indicative value for a contact of the clamping surface with a tool or workpiece to be clamped and the associated clamping state the contact between the clamping surface and the tool or workpiece and / or the characteristic hydraulic medium indication value is a characteristic hydraulic medium pressure -Indikationswert at a stop of the clamping screw on a limiting the axial displacement of the clamping screw stop and the associated clamping state reaching a predefined set clamping force of the hydraulic expansion device used. The predefined set clamping force should be achieved with an intact hydro-Dehnspanneinrichtung to slight deviations, for example, due to manufacturing tolerances of the tensioned tool or workpiece. With increasing number of actuation of the hydraulic expansion device, however, their wear and thus the maximum clamping force to be achieved increases, so that the predetermined nominal clamping force will no longer be reached at some point. Alternatively or additionally, the following partial steps can be carried out in step b) in order to determine a clamping state of the hydraulic expansion clamping device by evaluating the measured hydraulic medium pressure indication values:

b3) calculating slopes of the hydraulic medium pressure indication values measured in step a) at predetermined, uniform measuring distances during screwing in of the tensioning screw, wherein a gradient consists of a difference between two respectively successively measured hydraulic medium pressure indication values or their amount as dividend and the measuring distance between the two considered hydraulic medium pressure indication values is formed as a divisor,

b4) determining a slope change between every two calculated slopes,

b5) checking whether the specific change in slope lies outside a predefined range, and thus there is a significant change in slope,

b6) determining a possible cause for the significant change in slope, in particular by using further measured and / or desired values, and

b7) Closing to a clamping state of the hydro-expansion chuck based on the specific cause.

A calculation of slopes and consideration of slope changes offers, in contrast to a mere consideration of absolute values, the advantage that characteristic pressure jumps can be detected for the hydraulic expansion chuck used.

Before calculating the slopes in step b3), the hydraulic medium pressure indication values measured in step a) can be compared to a scale can be plotted with multiples of the measuring distance between two directly successively measured hydraulic medium pressure indication values and the resulting measured value curve can be smoothed in particular by calculating moving average values and / or at least one particular linear curve fitting can be performed on the measured value curve. As a result, significant changes in slope can be detected.

Preferably, in step b4) a change in slope between two slopes is determined, which were calculated in step b3) from three directly successively measured hydraulic medium pressure indication values. Since the two gradients used for the calculation of the change in slope follow one another directly in terms of messchronology, it can be clearly concluded in the case of a marked change in slope that this occurred in the middle of the three measured values considered. The slope change may be determined in step b4) by subtracting from one another or dividing by two slopes calculated in step b3). If two calculated slopes are divided to determine a slope change, the predefined area considered in the test in step b5) may be a predefined minimum multiple of one slope. A significant slope change is detected when a higher slope is a multiple of a lower slope of the two slopes considered and the corresponding multiple is greater than the predefined minimum multiple.

If, during the test in step b5), no clear change in pitch is detected until a stop limiting the axial adjustment of the clamping screw, it can be concluded that there is no tool or workpiece to be clamped or a tool with too small a shank or a workpiece with one suitable clamping diameter knife is used. If, however, a clear change in slope is detected, its cause can be determined in step b6) by using further measurement and / or setpoint values. As will be explained in more detail below, it is possible to use, for example, tension screw path indication values, setpoint values for tension screw path indication values and / or setpoint values for hydraulic medium pressure indication values. However, the cause of a significant change in slope can also be determined without taking further measurement and / or setpoint values. Because it is known that there must be at least two significant changes in pitch when screwing the clamping screw, a first contact with a clamping surface with a too exciting tool or workpiece and a second in a stop of the clamping screw on an axial displacement of the clamping screw limiting stop. Apart from the risk that a detected change in slope may also cause a malfunction of the hydraulic expansion device, such as a seizure of the clamping screw as the cause, it can be alone on whether it is the first time or second significant change in slope, close to one of the two aforementioned, characteristic of each hydraulic Dehnspanneinrichtung causes.

As already mentioned above, during a screwing in of the clamping screw, in addition to the hydraulic medium pressure indication values measured in step a), tension screw path indication values can be measured at predetermined, uniform measuring distances, the measuring distance between two directly successively measured hydraulic medium pressure indication values being the measuring distance between two directly consecutive measured clamping screw path indication values. In this case, in step b6) the cause for the presence of a significant change in slope is preferably preferred. is true by comparing a measured during the significant change in pitch Spannschraubenweg indicative value with at least one known, characteristic of the hydraulic Dehnspanneinrichtungstyp setpoint for the Spannschraubenweg indication value. The comparison of the Spannschraubeweg indication values thus represents a hedge, so that in fact the right cause for a detected significant change in slope is determined. The setpoint value for the tightening screw path indication value can be a tightening screw path indication value for a contact of the clamping surface with a tool to be clamped or workpiece and / or for a stop of the tightening screw on a stop limiting the axial displacement of the tightening screw.

When screwing in the clamping screw, the torque on the clamping screw is advantageously measured as the hydraulic medium pressure indicative value as already explained above, and a malfunction of the hydraulic expansion chuck is determined in step b6) as the cause of the presence of a marked change in pitch From a comparison of a measured in the significant change in inclination Schraubschraubeweg indication value with a setpoint for Spannschraubenweg indicative value shows that the measured Spannschraubenweg indicative value is outside of a range around the setpoint and thus significantly smaller than the setpoint. The malfunction of the hydro-expansion chuck can be determined as a seizure of the clamping screw in the threaded hole. A seizure of the clamping screw can result from the fact that the external thread of the clamping screw does not meet the required surface requirements or the clamping screw no longer has sufficient lubrication. In the last-mentioned constellation, however, as a cause for the presence of a significant change in slope instead of a malfunction of the hydraulic expansion device and a tool with a too large Shaft diameter or a workpiece with a too small hole can be determined. For example, if there is a tool with a large shaft diameter in a hydraulic expansion chuck, the shaft contacts the clamping surface sooner than expected and a clear change in pitch occurs already after a shorter tightening screw path.

Alternatively or in addition to the previously described use of screw path indication values in determining the cause of a significant change in slope, the cause for the presence of a significant change in slope can be determined in step b6) by a hydraulic medium pressure indication value measured with the significant change in slope having at least one previously known, for the hydraulic-Dehnspanneinrichtungstyp characteristic setpoint for the hydraulic medium pressure indication value is compared. In this case, the setpoint value for the hydraulic medium pressure indication value is preferably a hydraulic medium pressure indication value for a contact of the clamping surface with a tool or workpiece to be clamped and / or for a stop of the clamping screw on a stop limiting the axial adjustment of the clamping screw.

Conveniently, in step b6) of the method according to the invention, a contact of the clamping surface with a tool or workpiece to be clamped is taken as the cause for the presence of a significant change in inclination and, in step b7), the attainment of a minimum clamping force as clamping state is determined based on the specific cause.

The process according to the invention may preferably have the following further steps: Closing on a stop of the clamping screw on a stop limiting the axial adjustment of the clamping screw as a cause for the presence of a marked change in the pitch in step b6),

Comparing the hydraulic medium pressure indication value in the case of the marked change in inclination with a previously known setpoint value for the hydraulic medium pressure indication value characteristic of the hydraulic expansion chuck type used in the case of a stop of the clamping screw on a stop limiting the axial adjustment of the clamping screw,

Determining that the two compared hydraulic medium pressure indication values match within a predefined range, and

Closing upon reaching a target clamping force as a clamping state in step b7) based on the previous determination.

The aforementioned comparison of the hydraulic medium pressure indication values makes it possible to determine whether sufficient clamping force is available. Due to the fact that the clamping screw has reached the stop, this can not be concluded, since the maximum clamping force of a hydraulic expansion chuck significantly reduces with increasing number of actuations.

Advantageously, a tightening of the clamping screw by means of the rotary tool can be terminated if it is determined in step b) when evaluating the measured hydraulic medium pressure indication values that a predetermined switch-off condition is met. Here, the screwing of the clamping screw can be terminated in an electrical screwing by switching off the electric screwing. A mechanical shut-off is conceivable. The predetermined switch-off condition may be a previously known hydraulic medium characteristic of the hydraulic expansion-tensioner type used. pressure-lndikationswert be at a stop of the clamping screw on a limiting the axial displacement of the clamping screw stop, for example, a defined maximum torque for the hydraulic Dehnspanneinrichtung, which must be achieved within a predefined range. When measuring the torque as a variable complementary to the pressure of the hydraulic medium, screwing in can be ended, for example, if an upper threshold value for a torque difference of 500 mNm, for example, or if a corresponding torque gradient value of, for example, 15000 mNm / ° is exceeded. Timely termination of the operation prevents damage to the hydraulic expansion jig.

Preferably, the clamping state determined in step c) is signaled to the user by being displayed via an optical signal, an acoustic signal or a vibration signal.

The aforementioned object is also according to the invention by a device for actuating a hydraulic Dehnspanneinrichtung, in particular a hydraulic expansion chuck or hydraulic Dehnspanndorns, with a base assembly in which a filled with a hydraulic medium pressure chamber system is formed, the pressure chamber having a wall, the on a side facing away from the pressure chamber defining a clamping surface, and introduced from the outside into the main body assembly and connected via connecting channels with the pressure chamber threaded surrounds, wherein in the threaded bore a clamping screw is screwed, which is axially adjusted by screwing into the threaded bore in that the hydraulic medium is pressed in the direction of the pressure chamber and the wall is elastically deformed in order to tension a tool or workpiece. In this case, the device according to the invention has: a holding device, in particular stationary holder, which is designed to support a torque applied to the hydraulic expansion device when the clamping screw is rotated,

a measuring device which is designed to measure hydraulic medium pressure indication values at predetermined, uniform measuring distances and / or continuously during the rotation of the clamping screw,

an evaluation and control device, which is designed to evaluate hydraulic medium pressure indication values measured by the measuring device and to determine a clamping state of the hydraulic expansion device, and

a signaling device which is designed to signal the determined by the evaluation and control unit clamping state of the hydraulic expansion device to a user.

The holding device may be a vise or gripper. But it can also be a support arm or a HSK, or steep taper tensioner with collet set, which is adapted to fix the hydraulic expansion chuck. The holding device may have support surfaces corresponding to support surfaces on the hydraulic expansion device.

The device according to the invention preferably has a rotary tool which is designed to rotate the clamping screw. The turning tool can be, for example, a bit, in particular a hexagon bit, or a wrench, in particular a hexagon wrench.

Advantageously, the device according to the invention has a screw device, in particular an electric screw device, on which the rotary tool is held in order to automatically turn the clamping screw. The apparatus according to the invention may comprise an adjusting device with a holder for the rotary tool or a screwing device on which the rotary tool is held, to automatically align the rotary tool relative to the hydraulic expansion chuck and automatically engage with the clamping screw. In this case, the adjustment device can have a 1-, 2-, 3-, or 5-axis kinematics and, in particular, be an industrial robot, such as an articulated robot, or a combination of linear modules and axes of rotation. Alternatively, it is possible in a stationary installed system to completely dispense with a kinematics and to realize the torque transmission from a rotary tool to the clamping screw via a flexible shaft.

The measuring device preferably comprises a pressure sensor, which is designed to measure the pressure of the hydraulic medium as hydraulic medium pressure indication values in the pressure chamber system and / or on the tensioning screw during a screwing in of the tensioning screw. In some hydraulic Dehnspanneinrichtungen adjacent to the threaded bore of the pressure chamber system in the axial direction of a cylinder bore of the pressure chamber system in which a clamping piston is contacted the clamping screw or connected thereto, so that an axial adjustment of the clamping screw when screwed into the threaded bore causes an axial adjustment of the clamping piston. In this case, the pressure transducer may be designed to measure the pressure of the hydraulic medium instead of the clamping screw on the clamping piston.

Advantageously, the measuring device is designed to measure values of a variable complementary to the pressure of the hydraulic medium as a hydraulic medium pressure indication value during a screwing-in of the clamping screw. For this purpose, the measuring device to a strain gauge the basic body arrangement, which is designed to measure a deformation, in particular an expansion and / or an elongation, of the basic body arrangement as a variable complementary to the pressure of the hydraulic medium, as hydraulic medium pressure indication values. Alternatively or additionally, the measuring device can be designed to measure the torque as a variable complementary to the pressure of the hydraulic medium as hydraulic medium pressure indication values during a rotation of the clamping screw. For this purpose, the measuring device may comprise a mounted on a torsion strain gauges, which is adapted to measure the torsion of the torsion, so that from the torque on the clamping screw and, in turn, the pressure of the hydraulic medium can be calculated. If the device according to the invention comprises an electric screwing device with a motor on which the rotary tool is held, the measuring device may also comprise an ammeter which is adapted to measure the motor current of the electric screwing device at a constant motor speed, thus the torque on the clamping screw and from which in turn the pressure of the hydraulic medium can be calculated.

According to one embodiment of the invention, the measuring device is designed to measure clamping screw path indication values, in particular beginning with the occurrence of a predetermined trigger event or by measuring a predetermined trigger value at predetermined, uniform measuring distances and / or continuously during a screwing in of the clamping screw. wherein the measuring distance between two directly successively measured hydraulic medium pressure indication values in particular corresponds to the measuring distance between two instantly measured clamping screw path indication values. In this case, the trigger event may be a contact of the clamping surface with a tool or work to be clamped. piece and / or a stop of the clamping screw on a limiting the axial displacement of the clamping screw stop and / or be the trigger value for the hydraulic expansion device used in a given trigger event characteristic value of the pressure of the hydraulic medium or a complementary size ,

The measuring device may be designed to measure values of the axial path position of the clamping screw within the threaded bore and / or values of a variable complementary to the axial path position of the clamping screw as clamping screw path indication values.

Preferably, the measuring device is adapted to the rotation angle of the clamping screw as a complementary to the axial path position of the clamping screw within the threaded bore size as Spannschraubenweg indicative values either directly on the clamping screw or on the rotary tool or on a screwing device on which the rotary tool is held measure up. The measuring device may have an encoder and / or Hall sensors to measure the angle of rotation of the clamping screw. The evaluation and control device can be designed to calculate the distance traveled by the clamping screw using a measured angle of rotation and a known pitch of the thread of the clamping screw.

Advantageously, the evaluation and control device is designed to check whether a hydraulic medium pressure indication value measured during insertion of the tensioning screw lies within a predefined range around a hydraulic medium pressure indication value characteristic of the hydraulic expansion chuck type used, and to a characteristic hydraulic pressure indicative value associated clamping state of the hydro-Dehnspanneinrichtung to close when the Exam is positive. In this case, the characteristic hydraulic medium pressure indication value may be a characteristic hydraulic medium pressure indication value for a contact of the clamping surface with a tool or workpiece to be clamped and the associated clamping state the contact between the clamping surface and the tool or workpiece and / or the characteristic hydraulic medium indication value a characteristic hydraulic medium pressure -Indikationswert in a stop of the clamping screw on a limiting the axial displacement of the clamping screw stop and the associated clamping state to achieve a predefined set clamping force of the hydraulic expansion device used.

The evaluation and control device can also be designed to:

Ascertain gradients of hydraulic medium pressure indication values measured at predetermined, uniform measuring distances during screwing in of the tensioning screw by the measuring device, wherein an inclination comprises a difference between respectively two consecutively measured hydraulic medium pressure indication values or their amount as dividend and the measuring distance between the two considered hydraulic medium pressure values. Indication values is formed as a divisor,

determine a slope change between every two calculated slopes,

to check whether the particular slope change is outside a predefined range, and thus a significant change in slope is present,

to determine a possible cause of the significant change in slope, in particular by using further measurement and / or setpoint values, and

based on the specific cause to close a clamping state of the hydraulic expansion device. Advantageously, the evaluation and control device is designed to apply the hydraulic medium pressure indication values measured by the measuring device against a scale with multiples of the measuring distance between two directly measured hydraulic medium pressure indication values before calculating the slopes, and the resulting measured value curve in particular by calculating moving average values Smooth and / or perform at least one particular linear curve fitting on the measured value curve.

Preferably, the evaluation and control device is designed to determine a change in slope between two gradients, which were calculated from three directly successively measured hydraulic medium pressure indication values.

The evaluation and control device may be configured to determine the slope change by subtracting from one another or dividing by two calculated slopes.

As already mentioned above, during a screwing in of the clamping screw, the measuring screw can measure clamping screw path indication values at predetermined uniform measuring distances in addition to the hydraulic medium pressure indication values, the measuring distance between two directly successively measured hydraulic medium pressure indication values being the measuring distance between two directly successively measured Spannschraubenweg indication values. In this case, the evaluation and control device is preferably designed to determine the cause of the presence of a significant change in the pitch by comparing a tension screw gauge measured during the significant change in pitch. to be determined with at least one known, characteristic of the hydraulic Dehnspanneinrichtungstyp setpoint for the Spannschraubenweg indication value. Here, the desired value for the Spannschraubenweg-Indikationswert a Spannschraubenweg indicative value at a contact of the clamping surface with a tool or workpiece to be clamped and / or a stop of the clamping screw on a the axial displacement of the clamping screw limiting stop.

Advantageously, the measuring device is designed to measure when screwing the clamping screw, the torque on the clamping screw as complementary to the pressure of the hydraulic medium size as hydraulic medium pressure indication value, and the evaluation and control device is adapted to a measured in the significant change in pitch Spannschraubeweg indicative value to compare with a set point for the Spannschraubenweg Indikationswert and as a cause for the presence of a significant change in slope to determine a malfunction of the hydraulic expansion device, if it is clear from the comparison that the measured Spannschraubenweg indication value is outside a range around the setpoint and thus significantly smaller than the nominal value. In this case, the malfunction of the hydraulic expansion chuck may be a seizure of the clamping screw in the threaded bore.

Preferably, the evaluation and control device is designed to determine the cause of the presence of a significant change in slope by comparing a measured at the significant change in slope hydraulic pressure indication value with at least one known, characteristic of the hydraulic Dehnspanneinrichtungstyp setpoint for the hydraulic medium pressure indication value , In this case, the desired value for the hydraulic medium pressure indication value can be a hydraulic likmediumdruck-lndikationswert at a contact of the clamping surface with a tool or workpiece to be clamped and / or a stop of the clamping screw on a limiting the axial displacement of the clamping screw stop.

The evaluation and control device may be designed to conclude a contact of the clamping surface with an exciting tool or workpiece as the cause of the presence of a significant change in slope and based on this cause to conclude the achievement of a minimum clamping force as a clamping state.

The evaluation and control device can also be designed to: to conclude a stop of the clamping screw on a limiting the axial displacement of the clamping screw stop as a cause for the presence of a significant change in slope,

to compare the hydraulic medium pressure indication value measured by the measuring device with the marked change in gradient with a previously known setpoint value for the hydraulic medium pressure indication value which is characteristic for the hydraulic expansion device type used in the case of a stop of the clamping screw on a stop limiting the axial adjustment of the clamping screw;

determine a match of the two compared hydraulic medium pressure indication values within a predefined range, and

to conclude based on this finding on reaching a target clamping force as a clamping state.

Preferably, the evaluation and control device is designed to check whether a predetermined switch-off condition is met, and to effect a termination of a screwing of the clamping screw when the test positive. In this case, the predetermined switch-off condition may be a previously known hydraulic medium pressure indication value characteristic of the hydraulic expansion-tensioning device type used in the event of a stop of the clamping screw on a stop limiting the axial adjustment of the clamping screw.

The signaling device expediently comprises a luminaire, a loudspeaker, a display and / or a vibration device.

With regard to further advantages and further possible embodiments of the device according to the invention, reference is made to the statements in connection with the method according to the invention to avoid repetition.

Further features and advantages of the present invention will become apparent from the following description of five embodiments of a device for operating a hydro-Dehnspanneinrichtung according to the present invention and an operable by a method according to the present invention Hydro-Dehnspannfutters with reference to the accompanying drawings. In it is:

Figure 1 is a schematic perspective view of a device according to the invention for actuating a hydraulic Dehnspanneinrichtung according to a first embodiment of the present invention;

Figure 2 is a schematic perspective view of a device according to the invention for actuating a hydraulic expansion chuck according to a second embodiment of the present invention; a schematic perspective view of a device according to the invention for operating a hydraulic expansion device according to a third embodiment of the present invention; a schematic perspective view of a device according to the invention for actuating a hydraulic expansion device according to a fourth embodiment of the present invention; a schematic perspective view of a device according to the invention for operating a hydraulic expansion chuck device according to a fifth embodiment of the present invention; a schematic perspective view of an actuatable by a method according to the present invention Hydro-Dehnspannfutters; a sectional view taken along a longitudinal center plane of the hydraulic expansion chuck of Figure 6; a sectional view taken along the section line VIII-VIII in Figure 7; and a torque curve as a function of the angle of rotation for a hydraulic expansion chuck without or with tools in a central tool holder. FIGS. 1 to 5 show schematic perspective views of a device according to the invention for actuating a hydraulic expansion chuck 1 according to five different embodiments of the present invention. The device 1 according to the invention has, in all five embodiments, a holding device 2 in which a hydraulic unit is mounted -Dehnspanneinrichtung 3 is fixed in the form of a hydraulic expansion chuck.

The hydraulic expansion chuck 3 is shown in detail in FIGS. 6 to 8. It comprises a basic body arrangement 4 with a main body 5, which at its rear end region has a machine interface 6, by means of which the hydraulic expansion chuck 3 is fixed to the holding device 2, and on its opposite side has a clamping region 7. In a central region of the main body 5 between the rear end region and the clamping region 7, a threaded bore 8 is introduced from the outside into the main body 5, in which a clamping screw 9 is screwed. The threaded bore 8 has at its inner end an axial displacement of the clamping screw 9 within the threaded bore 8 limiting stop 10. Adjacent to the threaded bore 8 in the axial direction, a cylinder bore 1 1, in which a clamping piston 12 is located, which is connected on one side with the clamping screw 9 and on its opposite side with a sealing element 13. The main body assembly 4 is in addition to the main body 5 still from an expansion sleeve 14. The expansion sleeve 14 is metallically connected to form a Dehnbüchse 14 surrounding pressure chamber 15 in the clamping portion 7 of the body 5 with the main body 5 and forms a front end face 16 of the main body fifth open tool holder 17. The pressure chamber 15 thus has a wall 18 which defines a clamping surface 19 on a side facing away from the pressure chamber 15 side. In addition, the pressure chamber 15 via connection channels to form one with a hydraulic medium filled pressure chamber system with the cylinder bore 1 1 and the threaded hole 8 connected and thus acted upon by the hydraulic medium. As can be seen in Figures 1 to 5, a tool 20 is inserted into the tool holder 17.

In addition, the device 1 according to the invention in all five embodiments, an electric screw 21 with a motor on which a hexagon bit 22 is rotatably supported as a rotary tool. The device 1 according to the invention also has, in all five embodiments, a measuring device 23 which comprises an ammeter and an encoder. Both the ammeter and the encoder are integrated in the electric screw 21. As shown in Figures 6 and 7, the measuring device 23 also includes a mounted on the outside of the base body 5 strain gauge 24, which is not shown in Figures 1 to 5 for the sake of clarity. In addition, in all five embodiments, the device 1 according to the invention has an evaluation and control device 25 connected to the measuring device 23 as well as a signaling device 26 connected to the evaluation and control device 25 in the form of two LED lights.

In the following, the technical differences of the five embodiments of the device 1 according to the invention for actuating a hydraulic expansion chuck 3 are discussed.

In the first embodiment in FIG. 1, the holding device 2 for the hydraulic expansion chuck 3 is a stationary holder which is fixed on a base plate 27 of the device 1. In this embodiment, the device 1 additionally comprises an adjusting device 28 which has a holder 29 for the electric screw 21 and a 1-axis kinematics 30 summarized. The adjusting device 28 is also fixed on the base plate 27.

In the second embodiment in FIG. 2, the holding device 2 for the hydraulic expansion chuck 3 comprises a displaceable shaft 31 and two pivot joints 32 and thus has a translational and two rotational degrees of freedom in order to align and position the hydraulic expansion chuck 3 to be able to adjust. The holding device 2 is fixed on a base plate 27 of the device 1. As in the first embodiment, also in the second embodiment, the device 1 has an adjusting device 28 which comprises a holder 29 for the electric screwing device 21 and a 1-axis kinematics 30. The adjusting device 28 is also fixed on the base plate.

In the third embodiment in FIG. 3, the holding device 2 for the hydraulic expansion chuck 3 is a stationary holder which is fixed on a base plate 27 of the device 1. The device 1 also has here an adjusting device 28. In contrast to the first and second embodiments, however, the adjusting device 28 is not a 1-axis kinematics, but an industrial robot.

In the fourth embodiment in FIG. 4, the holding device 2 for the hydraulic expansion chuck 3 is a stationary holder which is fixed on a base plate 33 of a gripping robot arrangement 34. From a connected to the base plate 33, vertically extending main unit 35 of the gripping robot assembly 34 projects a gripping arm 36 for feeding and discharging to be operated hydraulic expansion chucks. As in the first and second embodiments, also in the fourth embodiment, the device 1 has an adjusting device 28 which comprises a holder 29 for the electric screwing device 21 and a 1-axis kinematics 30. The Adjustment device 28 is connected to the base plate 33 of the gripper robot assembly 34.

In the fifth embodiment in FIG. 5, the hydro-expansion chuck 3 holding device 2 is a stationary support having a base plate 37 that includes through-holes 38 for fixing the holding device 2 to a table. In contrast to the four aforementioned embodiments, the device 1 according to the fifth embodiment does not include an adjusting device 28. Instead, the electric screwing device is designed as a mobile cordless screwdriver which can be charged via a loading device.

During operation of the device for actuating a hydraulic expansion chuck 1, the electric screwing device 21 is aligned either manually - as in the fifth embodiment - or automatically by means of the adjusting device 28 - as in the first four embodiments - relative to the hydraulic expansion chuck 3 and engaged with the tightening screw 9. In FIGS. 6 and 8, an arrow indicates in which direction the alignment takes place. The clamping screw 9 is now screwed by means of the electric screw 21 in the threaded hole 8 until the clamping screw 9 comes to rest on the stop 10. The torque applied to the hydraulic expansion chuck 3 during the screwing in of the clamping screw 9 is supported by the holding device 2. The clamping screw 9 is adjusted axially when screwing into the threaded hole 8. Since the clamping screw 9 is connected to the clamping piston 12, causes the axial adjustment of the clamping screw 9 and an axial adjustment of the clamping piston 12 together with the sealing element 13. As a result, the hydraulic medium is pressed within the pressure chamber system in the direction of the pressure chamber 15, whereby the wall 18 elastic deformed or expanded hydraulically becomes. As a result of the widening of the wall 18, a joining play between the wall 18 and the tool 20 to be clamped is first of all compensated and the wall 18 is then pressed against the tool 20 to be clamped, whereby a frictional connection between the hydraulic expansion chuck 3 and the tool 20 results.

During the screwing in of the clamping screw 9, the strain gauge 24 of the measuring device 23 measures a deformation, in particular an expansion, of the main body 5 as a variable complementary to the pressure of the hydraulic medium as hydraulic medium pressure indication values. In addition, the measuring device 23 measures by means of the ammeter the motor current of the electric screw 21 at a constant engine speed and thus indirectly the torque of the clamping screw as a further to the pressure of the hydraulic medium complementary size as hydraulic medium pressure indication values in predetermined, uniform intervals. Furthermore, the measuring device 23 measures by means of the encoder the angle of rotation of the clamping screw 9 as a complementary to the axial path position of the clamping screw 9 within the threaded bore 8 size as Spannschraubenweg indicative values in predetermined, uniform measuring distances. The measurement of the angle of rotation begins in this embodiment with the occurrence of a trigger event, namely the contact of the clamping surface 19 with the tool 20. Of course, the measurement can also start at another time or take place from the beginning. The measuring distance between two directly successively measured torques corresponds to the measuring distance between two directly consecutively measured angles of rotation. After a rotation of the clamping screw 9 by a certain angular range so in each case the torque is measured on the clamping screw 9. The evaluation and control device 25 then checks whether a measured during the tightening of the clamping screw 9 torque or a measured deformation within a predefined range to a characteristic of the hydraulic expansion chuck 3 torque or a characteristic deformation, and includes one of the characteristic Torque or the characteristic deformation associated clamping state, if the test is positive. Here is a characteristic torque / deformation on the one hand a characteristic torque / deformation in a contact of the clamping surface 19 with the tool 20 and the associated clamping state of the contact between the clamping surface 19 and the tool 20 and the achievement of a minimum clamping force. On the other hand, the characteristic torque / deformation is a characteristic torque / deformation at a stop of the clamping screw 9 on the stop 10 and the associated clamping state reaching a predefined set clamping force.

In addition, the evaluation and control device 25 calculates slopes of the measured torques, wherein a slope from the amount of a difference between each two immediately successively measured torques is formed as a dividend and the measuring distance between the two considered torques as a divisor. Now, the evaluation and control device 25 determines a change in slope between each two calculated slopes, which were calculated from three directly successively measured torques. For this purpose, the two calculated slopes are divided. Subsequently, it is checked whether the specific slope change is outside a predefined range, and thus there is a significant change in slope. For example, a significant slope change occurs when the slopes are many times different. Now, a possible cause for a noticeable change in slope is is correct and based on the specific cause closed to a clamping state.

The cause of the presence of a significant change in slope is determined by comparing a measured during the significant change in slope torque with at least one previously known, characteristic of the hydraulic expansion chuck setpoint for the torque. Here, the desired value for the torque is a torque at a contact of the clamping surface 19 with the tool 20 and / or at a stop of the clamping screw 9 on the stop 10. For further protection, the measured rotation angle are used. The measured during the significant change in slope angle of rotation is compared with at least one known, characteristic of the hydraulic expansion chuck 3 setpoint for the rotation angle. If it is found that the measured angle of rotation is significantly smaller than the target value, a malfunction of the hydraulic expansion chuck 3, such as a seizure of the clamping screw 9, is determined as the cause for the presence of the significant change in pitch.

If a contact of the clamping surface 19 with the tool 20 is concluded as the cause for the presence of the clear change in slope, then, based on this cause, the achievement of a minimum clamping force as the clamping state is concluded. If, however, a stop of the clamping screw 9 at the stop 10 as a cause for the presence of significant change in slope is closed, the torque measured at the significant change in slope with a known, characteristic of the hydraulic expansion chuck setpoint for the torque at a stop the clamping screw 9 compared to the stop 10. If a match of the two torques compared with each other within a predefined range is determined, Close to this finding on the achievement of a desired clamping force as a clamping state.

The respective particular state of tension is then displayed to a user via a lighting up of a corresponding LED light 26.

FIG. 9 qualitatively shows two typical measuring curves which can be obtained during the previously described actuating method during screwing in of the clamping screw 9. Specifically, the measured torques are plotted against the measured angles of rotation.

The measuring curve designated II shows a typical torque curve in the event that a tool 20 is in the tool holder 17 of the hydraulic expansion chuck 3. The trace has three sections each of different pitch. In a first section (1), the torque in an approximation is linearly proportional to a strain rate of the wall 18. In this section, a screwing of the clamping screw 9 causes an expansion of the wall 18. As soon as the clamping surface 19 contacts the shank of the tool 20, which at point A of the trace II, there is a positive pressure jump, ie a sudden increase in the pressure of the hydraulic medium in the pressure chamber system of the hydraulic expansion chuck 3, which is noticeable by a significant increase in the slope of the trace. At the point A of the measuring curve II, the first section thus merges into a second section with a significantly higher gradient than the first section. In this second section, no change in the expansion rate occurs. Rather, it comes with a further screwing the clamping screw 9 in the direction of the stop 10 to an increase in the pressure of the hydraulic medium. This is partly due to the fact that hydraulic media, in particular hydraulic oils, are included in the high pressures prevailing in hydraulic expansion chucks. least slightly compressible. In this case, the torque in the second section is linearly proportional to the pressure of the hydraulic medium. Once the clamping screw 9 reaches the stop 10, there is a second positive pressure jump, which is noticeable by a further significant increase in the slope of the measuring curve II due to the force acting through the stop 10 additional axial force. The point B of the measuring curve II therefore indicates a chronologically second pressure jump. Here the second section merges into a third section with a significantly higher slope than the second section. The fact that the tensioning screw 9 can still be turned a little further in the third section depends inter alia on the fact that components of the hydraulic expansion chuck 3, such as the stop 10, are still compressed slightly elastically.

The measurement curve designated I shows a typical torque curve in the event that no tool 20 is in the tool holder 17 of the hydraulic expansion chuck 3. The measurement curve has only one pressure jump at the point B, which is due to the fact that the clamping screw 9 reaches the stop 10. Since there is no tool 20 in the tool holder 17, there can be no further pressure jump at the point A, since it can never happen that the clamping surface 19 contacts the tool 20.

LIST OF REFERENCE NUMBERS

1 Device for actuating a hydraulic expansion chuck

2 holding device

3 hydraulic expansion chucks

4 basic body arrangement

5 basic body

6 machine interface

7 clamping range

8 threaded hole

9 clamping screw

10 stop

1 1 cylinder bore

12 tensioning pistons

13 sealing element

14 expansion sleeve

15 pressure chamber

16 front face of the body

17 tool holder

18 wall

19 clamping surface

20 tool

21 electric screwing device

22 hex bits

23 measuring device

24 strain gauges

25 evaluation and control device

26 signaling device

27 base plate

28 adjustment device Holder for electric screwing device

1-axis kinematics

movable axis

swivel

baseplate

Greifarnnroboteranordnung

main unit

claw arm

plinth

Through Hole

loader

Claims

1. A method for actuating a hydraulic Dehnspanneinrichtung (3), in particular a hydraulic expansion chuck or hydraulic Dehnspanndorns, with a base body assembly (4) in which a filled with a hydraulic medium pressure chamber system is formed, which a pressure chamber (15) a wall (18) which defines a clamping surface (19) on a side facing away from the pressure chamber (15) and comprises a threaded bore (8) introduced from the outside into the basic body arrangement (4) and connected via connecting channels to the pressure chamber (15), wherein in the threaded bore (8) a clamping screw (9) is screwed, which is adjusted by screwing into the threaded bore (8) axially such that the hydraulic medium in the direction of the pressure chamber (15) pressed and the wall (18) is elastically deformed in order to tension a tool (20) or workpiece, wherein in the method the clamping screw (9) is rotated by means of a turning tool (22) and that onto the hydraulic expansion chuck (3) Torque applied in particular by fixing the hydraulic expansion device (3) in a stationary support (2) is supported, characterized by the steps:

a) Measuring hydraulic medium pressure indication values by means of a measuring device (23) at predetermined, uniform measuring distances and / or continuously during rotation of the clamping screw (9), b) determining a clamping state of the hydraulic expansion device (3) by evaluating the measured hydraulic medium pressure indication values by means of an evaluation and control device (25) and

c) signaling the determined clamping state of the hydraulic expansion device (3) by means of a signaling device (26) to a user.

2. The method according to claim 1, characterized in that the

Rotary tool (22) is automatically aligned relative to the hydraulic expansion device (3) and automatically brought into engagement with the clamping screw (9).

3. The method according to claim 1 or 2, characterized in that the clamping screw (9) automatically by means of a screw device (21), in particular an electric screwing device, on which the rotary tool (22) is held, or manually by means of the rotary tool (22 ), in particular a screwdriver, is twisted.

4. The method according to any one of claims 1 to 3, characterized in that in step a) during a screwing of the clamping screw (9) values of the pressure of the hydraulic medium are measured as hydraulic medium pressure indication values in the pressure chamber system via a pressure transducer.

5. The method according to any one of claims 1 to 4, characterized in that in step a) during a screwing of the clamping screw (9) values of the pressure of the hydraulic medium are measured as hydraulic medium pressure indication values on the clamping screw (9) via a pressure transducer.

6. The method according to any one of claims 1 to 4, characterized in that an axial adjustment of the clamping screw (9) when screwed into the threaded bore (8) causes an axial displacement of a clamping piston (12), which is in an axial direction the threaded bore (8) is located adjacent cylinder bore (1 1) of the pressure chamber system and the clamping screw (9) is contacted or connected to this, and in Step a) during a screwing of the clamping screw (9) values of the pressure of the hydraulic medium are measured as hydraulic medium pressure indication values on the clamping piston (12) via a pressure transducer.

7. Method according to one of the preceding claims, characterized in that in step a) values of a variable complementary to the pressure of the hydraulic medium are measured as hydraulic medium pressure indication values during a screwing in of the clamping screw (9).

8. The method according to claim 7, characterized in that a deformation, in particular an expansion and / or elongation of the main body assembly (4) as a complementary to the pressure of the hydraulic medium size as hydraulic medium pressure indication values by means of a strain gauge (24) is measured.

9. The method according to claim 7 or 8, characterized in that the torque on the clamping screw (9) is measured as a complementary to the pressure of the hydraulic medium size as hydraulic medium pressure indication values.

10. The method according to claim 9, characterized in that the measurement of the torque on the clamping screw (9) via a measurement of the torsion of a torsion by means of a mounted on the torsion strain gauge takes place.

11. The method according to claim 9 or 10, characterized in that the clamping screw (9) by means of an electric screw device (21) on which the rotary tool (22) is held, is rotated and the measurement of the torque on the clamping screw (9) via a measurement of the mo- torstromes a motor of the electric screw device (21) takes place at a constant engine speed.

12. The method according to any one of the preceding claims, characterized in that Spannschraubenweg indicative values during a screwing of the clamping screw (9) in particular starting with the occurrence of a predetermined trigger event or with the measurement of a predetermined trigger value in predetermined, uniform measuring distances and / or continuously measured.

13. The method according to claim 12, characterized in that the trigger event is a contact of the clamping surface (19) with an exciting tool (20) or workpiece and / or a stop of the clamping screw (9) on an axial adjustment of the clamping screw ( 9) limiting stop (10) and / or the trigger value is a value for the hydraulic expansion device used (3) at a given trigger event characteristic value of the pressure of the hydraulic medium or a complementary size.

14. The method according to claim 12 or 13, characterized in that values of the axial travel position of the clamping screw (9) within the threaded bore (8) are measured as Spannschraubenweg indicative values.

15. The method according to any one of claims 12 to 14, characterized in that values of a complementary to an axial path position of the clamping screw (9) within the threaded bore (8) size are measured as Spannschraubenweg indicative values.

16. The method according to claim 15, characterized in that the angle of rotation of the clamping screw (9) as a to the axial position of the Clamping screw (9) within the threaded bore (8) complementary size as Spannschraubenweg indicative values, preferably by means of an encoder and / or Hall sensors, either directly on the clamping screw (9) or on the rotary tool (22) or on a screw (21 ), on which the rotary tool (22) is held, is measured.

17. The method according to claim 16, characterized in that is calculated using the measured angle of rotation and a known pitch of the thread of the clamping screw (9) of the distance traveled the clamping screw (9).

18. The method according to claim 12, characterized in that the measuring distance between two immediately following measured hydraulic medium pressure indication values the measuring distance between two immediately successively measured Spannschraubenweg indicative values, in particular a predetermined path step, angle step or time step at a constant insertion speed of the clamping screw ( 9), corresponds.

19. The method according to any one of the preceding claims, characterized in that in step b) the following sub-steps are performed:

b1) checking whether a hydraulic medium pressure indication value measured during a tightening of the clamping screw (9) lies within a predefined range around a hydraulic medium pressure indication value characteristic of the hydraulic expansion chuck type used, and

b2) closing to a clamping state of the hydraulic expansion chuck (3) associated with the characteristic hydraulic medium pressure indication value if the test in step b1) is positive.

20. The method according to claim 19, characterized in that the characteristic hydraulic pressure indicative value is a characteristic hydraulic pressure indicative value at a contact of the clamping surface (19) with an exciting tool (20) or workpiece and the associated clamping state of the contact between the clamping surface (19 ) and the tool (20) or workpiece and / or that the characteristic hydraulic medium indication value a characteristic hydraulic pressure indicative value at a stop of the clamping screw (9) on a axial displacement of the clamping screw (9) limiting stop (10) and the associated Clamping state is the achievement of a predefined set clamping force of the hydraulic expansion device used (3).

21. The method according to any one of the preceding claims, characterized in that in step b) the following sub-steps are carried out:

b3) calculating slopes of the hydraulic medium pressure indication values measured in step a) at predetermined, uniform measuring distances during screwing in of the clamping screw (9), wherein a gradient consists of a difference between in each case two successively measured hydraulic medium pressure indication values or their amount as dividend and the measuring distance is formed as a divisor between the two considered hydraulic medium pressure indication values,

b4) determining a slope change between every two calculated slopes,

b5) checking whether the specific change in slope lies outside a predefined range, and thus there is a significant change in slope, b6) determining a possible cause for the significant change in slope, in particular by using further measured and / or desired values, and

b7) Closing to a clamping state of the hydraulic expansion jig (3) based on the specific cause.

22. The method according to claim 21, characterized in that in step b4) a slope change between two slopes is determined, which were calculated in step b3) from three directly successively measured hydraulic medium pressure indication values.

23. The method according to claim 21 or 22, characterized in that in step b4) the slope change by subtracting each other or dividing by dividing two in step b3) calculated slopes is determined.

24. The method according to any one of claims 21 to 23, characterized in that prior to calculating the slopes in step b3) the measured in step a) hydraulic medium pressure indication values are plotted against a scale with multiples of the measuring distance between two immediately successively measured hydraulic medium pressure indication values and the resulting measured value curve is smoothed in particular by calculating moving average values and / or at least one in particular linear curve fitting is performed on the measured value curve.

25. The method according to claim 21, wherein in addition to the hydraulic medium pressure indication values measured in step a), tension screw path indication values according to one of claims 12 to 18 are measured and the measuring distance between two directly identifiable values is measured. following measured hydraulic medium pressure indication values corresponds to the measuring distance between two instantly measured clamping screw path indication values.

26. The method according to claim 25, characterized in that in step b6) the cause for the presence of a significant change in slope is determined by a measured at the significant change in pitch Spannschraubenweg indicative value with at least one known, characteristic of the hydraulic Dehnspanneinrichtungstyp nominal value for the tension screw path indication value is compared.

27. The method according to claim 26, characterized in that the desired value for the Spannschraubenweg-Indikationswert a Spannschraubenweg indicative value at a contact of the clamping surface (19) with an exciting tool (20) or workpiece and / or a stop of the clamping screw (9 ) is at a the axial displacement of the clamping screw (9) limiting stop (10).

28. The method of claim 26 or 27, characterized in that when screwing in the clamping screw (9) the torque on the clamping screw (9) as the pressure of the hydraulic medium complementary size as a hydraulic medium pressure indication value, in particular according to one of claims 9 to 1 1 , Measured and in step b6) a malfunction of the hydraulic expansion device (3) is determined as the cause for the presence of a significant change in pitch, if a comparison of a measured in the significant change in pitch Spannschraubeweg indication value with a target value for Spannschraubenweg- Indication value shows that the measured Spannschraubenweg indication value is outside a range around the setpoint and thus significantly smaller than the setpoint.

29. The method according to claim 28, characterized in that the malfunction of the hydraulic expansion device (3) as a seizure of the clamping screw (9) in the threaded bore (8) is determined.

30. The method according to any one of claims 21 to 29, characterized in that in step b6) the cause for the presence of a significant change in slope is determined by a measured at the significant change in slope hydraulic medium pressure indication value with at least one previously known, for the hydraulic ro-Gasket type characteristic setpoint for the hydraulic medium pressure indication value is compared.

31. Method according to claim 30, characterized in that the desired value for the hydraulic medium pressure indication value is a hydraulic medium pressure indication value for a contact of the clamping surface (19) with a tool (20) or workpiece to be clamped and / or during a stop of the clamping screw (9 ) on a axial displacement of the clamping screw (9) limiting stop (10).

32. The method according to any one of claims 21 to 31, characterized in that in step b6) on a contact of the clamping surface (19) with an exciting tool (20) or workpiece as the cause of the presence of a significant change in slope is closed and in step b7) is concluded based on the specific cause of reaching a minimum clamping force as a clamping state.

33. The method according to any one of claims 21 to 31, characterized in that it comprises the following further steps: Closing on a stop of the clamping screw (9) on a stop (10) delimiting the axial adjustment of the clamping screw (9) as the cause of the presence of a marked change in the pitch in step b6),

Comparing the hydraulic medium pressure indication value in the case of the marked change in inclination with a previously known setpoint value for the hydraulic medium pressure indication value used for the hydraulic expansion clamp type used in the case of a stop of the clamping screw (9) on a stop limiting the axial adjustment of the clamping screw (9),

34. The method according to any one of the preceding claims, characterized in that, when it is determined in step b) in evaluating the measured hydraulic pressure indication values that a predetermined shutdown condition is met, a screwing of the clamping screw (9) by means of the rotary tool (22) finished becomes.

35. The method according to claim 34, characterized in that the predetermined switch-off condition is a previously known hydraulic medium pressure indication value characteristic of the hydraulic expansion-tensioning device type used in the case of a stop of the tensioning screw (9) on a stop (10) delimiting the axial displacement of the tensioning screw (9). is that must be reached within a predefined range.

36. The method according to any one of the preceding claims, characterized in that the clamping state determined in step c) the user is signaled by being displayed via an optical signal, an acoustic signal or a vibration signal.

37. Apparatus for actuating a hydraulic expansion chuck (1), in particular a hydraulic expansion chuck or hydraulic expansion mandrel, with a base body assembly (4) in which a filled with a hydraulic medium pressure chamber system is formed having a pressure chamber (15) having a wall (18) which defines a clamping surface (19) on a side facing away from the pressure chamber (15), and a threaded bore (8) introduced from outside into the basic body arrangement (4) and connected via connecting channels to the pressure chamber (15), wherein the threaded bore (8) a clamping screw (9) is screwed, which is adjusted by screwing into the threaded bore (8) axially such that the hydraulic medium in the direction of the pressure chamber (15) pressed and the wall (18) is elastically deformed a tool (20) or workpiece to be clamped, wherein the device (1) comprises:

a holding device (2), in particular a stationary holder, which is designed to support a torque applied to the hydraulic expansion chuck (3) when the clamping screw (9) is rotated, characterized by

a measuring device (23) which is designed to measure hydraulic medium pressure indication values at predetermined, uniform measuring distances and / or continuously during the rotation of the clamping screw (9),

an evaluation and control device (25) which is designed to evaluate hydraulic medium pressure indication values measured by the measuring device (23) and to determine a clamping state of the hydraulic expansion clamping device (3), and a signaling device (26) which is designed to signal the clamping state of the hydraulic expansion chuck (3) determined by the evaluation and control unit (25) to a user.

38. Device (1) according to claim 37, characterized in that it comprises a rotary tool (22) which is adapted to rotate the clamping screw (9).

39. Device (1) according to claim 38, characterized in that it comprises a screwing device (21), in particular an electric screwing device, on which the rotary tool (22) is held in order to turn the clamping screw (9) automatically.

40. Device (1) according to claim 38 or 39, characterized in that it comprises an adjusting device (28) with a holder (29) for the rotary tool (22) or a screw device (21) on which the rotary tool (22) is held , to automatically align the rotary tool (22) relative to the hydraulic expansion jig (3) and automatically engage the clamping screw (9).

41. Device (1) according to claim 40, characterized in that the adjusting device (28) has a 1-, 2-, 3-, or 5-axis kinematics and in particular an industrial robot, such as a articulated robot, or a combination of linear modules and axes of rotation is.

42. Device (1) according to one of claims 37 to 41, characterized in that the holding device (2) has support surfaces corresponding to support surfaces on the hydraulic expansion device (3) and / or that the holding device (2) is a vise.

43. Device (1) according to any one of claims 37 to 42, characterized in that the measuring device (23) comprises a pressure transducer, which is designed, during a screwing of the clamping screw, the pressure of the hydraulic medium as hydraulic medium pressure indication values in the pressure chamber system to eat.

44. Device (1) according to any one of claims 37 to 43, characterized in that the measuring device (23) comprises a pressure sensor, which is designed, during a screwing of the clamping screw (9) the pressure of the hydraulic medium as hydraulic medium pressure indication values to measure on the clamping screw (9).

45. Device (1) according to one of claims 37 to 43, characterized in that an axial adjustment of the clamping screw (9) when screwed into the threaded bore (8) causes an axial displacement of a clamping piston (9), which is in an in axial direction to the threaded bore (8) adjacent cylinder bore (1 1) of the pressure chamber system is the clamping screw (9) contacted or connected thereto, the measuring device (23) comprises a pressure transducer, which is adapted during a screwing of the clamping screw (9 ) to measure the pressure of the hydraulic medium as hydraulic medium pressure indication values on the tensioning piston (12).

46. Device (1) according to one of claims 37 to 45, characterized in that the measuring device (23) is designed to measure values of a variable complementary to the pressure of the hydraulic medium as hydraulic medium pressure indication values during a screwing in of the clamping screw (9).

47. Device (1) according to claim 46, characterized in that the measuring device (23) comprises a strain gauge (24) on the main body assembly (4), which is adapted to a deformation, in particular an expansion and / or elongation, the Main body assembly (4) as a complementary to the pressure of the hydraulic medium size to measure as hydraulic medium pressure indication values.

48. Device (1) according to claim 46 or 47, characterized in that the measuring device (23) is adapted to measure the torque as a complementary to the pressure of the hydraulic medium size as hydraulic medium pressure indication values during a rotation of the clamping screw (9).

49. Apparatus according to claim 48, characterized in that the measuring device (23) comprises a mounted on a torsion strain gauges, which is adapted to measure the torsion of the torsion, so that from the torque on the clamping screw (9) and in turn the Pressure of the hydraulic medium can be calculated.

50. Device (1) according to claim 48 or 49, characterized in that it comprises an electric screwing device (21) with a motor, on which the rotary tool (22) is held, and the measuring device (23) comprises an ammeter connected thereto is designed to measure the motor current of the electric screw device (21) at a constant engine speed, so that from the torque on the clamping screw (9) and in turn the pressure of the hydraulic medium can be calculated.

51. A device (1) according to any one of claims 37 to 50, characterized in that the measuring device (23) is adapted to tensioning in particular starting with the occurrence of a predetermined trigger event or with the measurement of a predetermined trigger value at predetermined, uniform measuring distances and / or continuously during a screwing of the clamping screw (9), the measuring distance being measured between two directly consecutively measured values Hydraulic medium pressure indication values in particular the measuring distance between two immediately successively measured Spannschraubenweg indicative values corresponds.

52. Device (1) according to claim 51, characterized in that the trigger event is a contact of the clamping surface (19) with an exciting tool (20) or workpiece and / or a stop of the clamping screw (9) on an axial adjustment the tensioning screw (9) limiting stop (10) and / or the trigger value is a value for the hydraulic expansion device used (3) at a certain trigger event characteristic value of the pressure of the hydraulic medium or a complementary size.

53. Device (1) according to claim 51 or 52, characterized in that the measuring device (23) is adapted to measure values of the axial path position of the clamping screw (9) within the threaded bore (8) as Spannschraubenweg indicative values.

54. Device (1) according to one of claims 51 to 53, characterized in that the measuring device (23) is designed to values of an axial travel to the position of the clamping screw (9) within the threaded bore (8) complementary size as Spannschraubenweg indicative values to eat.

55. Device (1) according to claim 54, characterized in that the measuring device (23) is adapted to the angle of rotation of the clamping screw (9) as a to the axial position of the clamping screw (9) within the threaded bore (8) complementary size as Clamping screw path indication values either directly on the clamping screw (9) or on the rotary tool (22) or on a screwing device (21) on which the rotary tool (22) is held to measure.

56. Device (1) according to claim 55, characterized in that the measuring device (23) has an encoder and / or Hall sensors to measure the angle of rotation of the clamping screw (9).

57. Apparatus (1) according to claim 55 or 56, characterized in that the evaluation and control device (25) is adapted to, using a measured angle of rotation and a known pitch of the thread of the clamping screw (9) the path traveled the clamping screw ( 9).

58. Device (1) according to one of claims 37 to 57, characterized in that the evaluation and control device (25) is designed to check whether a measured during a tightening of the clamping screw (9) hydraulic medium pressure indication value within a predefined Range to a hydraulic medium pressure indicative value characteristic of the hydraulic expansion chuck type used, and to close a clamping state of the hydraulic expansion chuck (3) associated with the characteristic hydraulic medium pressure indication value, if the test is positive.

59. Device (1) according to claim 58, characterized in that the characteristic hydraulic medium pressure indication value is a characteristic shear hydraulic pressure indicative value at a contact of the clamping surface (19) with an exciting tool (20) or workpiece and the associated clamping state of the contact between the clamping surface (19) and the tool (20) or workpiece and / or that the characteristic hydraulic medium -Indikationswert a characteristic hydraulic medium pressure indication value at a stop of the clamping screw (9) on a axial displacement of the clamping screw (9) limiting stop (10) and the associated clamping state is the achievement of a predefined set clamping force of the hydraulic expansion device used (3).

60. Device (1) according to one of claims 37 to 59, characterized in that the evaluation and control device (25) is designed to:

Slopes of measured in predetermined, uniform measuring distances during a screwing of the clamping screw (9) by the measuring device (23) hydraulic medium pressure indication values, wherein a slope of a difference between two consecutively measured hydraulic medium pressure indication values or their amount as a dividend and the measuring distance is formed as a divisor between the two considered hydraulic medium pressure indication values, to determine a slope change between every two calculated slopes,

based on the specific cause to close a clamping state of the hydraulic expansion device (3).

61. Device (1) according to claim 60, characterized in that the evaluation and control device (25) is adapted to determine a change in slope between two slopes, which were calculated from three directly successively measured hydraulic medium pressure indication values.

62. Device (1) according to claim 60 or 61, characterized in that the evaluation and control device (25) is adapted to determine the slope change by subtracting from each other or dividing by dividing two calculated slopes.

63. Device (1) according to one of claims 60 to 62, characterized in that the evaluation and control device (25) is adapted to, before calculating the slopes of the measuring device (23) measured hydraulic medium pressure indication values against a scale with Multiples the measuring distance between two directly consecutively measured hydraulic medium pressure indication values and apply the resulting measured value curve, in particular by calculating moving average values and / or at least one particular linear curve adaptation to the measured value curve.

64. Device (1) according to one of claims 60 to 63, wherein the measuring device (23) according to any one of claims 51 to 57 is adapted to measure Spannschraubenweg indicative values, and the measuring distance between two immediately successively measured hydraulic medium pressure indication values the measurement distance between two immediately consecutive measured Spannschraubenweg indication values.

65. Device (1) according to claim 64, characterized in that the evaluation and control device (25) is designed to be the cause of the presence of a significant change in slope by comparing a measured in the significant change in pitch Spannschraubenweg indicative value with at least one previously known to determine the characteristic setpoint value for the tightening screw path indication value that is characteristic for the hydraulic expansion chuck type used.

66. Device (1) according to claim 65, characterized in that the desired value for the Spannschraubenweg-Indikationswert a Spannschraubenweg indicative value at a contact of the clamping surface (19) with a tool to be clamped (20) or workpiece and / or in a stop of Clamping screw (9) on a stop (10) delimiting the axial displacement of the tensioning screw (9).

67. Device (1) according to any one of claims 65 or 66, characterized in that the measuring device (23) is adapted, when screwing in the clamping screw (9), the torque on the clamping screw (9) as the pressure of the hydraulic medium complementary size to be measured as hydraulic medium pressure indication value, and the evaluation and control device (25) is adapted to compare a measured during the significant change in pitch Spannschraubeweg indicative value with a setpoint for Spannschraubenweg indicative value and as a cause for the presence of a significant change in slope a malfunction the hydro-Dehnspanneinrichtung (3) to determine when it is clear from the comparison that the measured Spannschraubenweg indicative value is outside a range around the setpoint and thus significantly smaller than the setpoint.

68. Device (1) according to claim 67, characterized in that the malfunction of the hydro-Dehnspanneinrichtung (3) is a seizure of the clamping screw (9) in the threaded bore (8).

69. Device (1) according to any one of claims 60 to 68, characterized in that the evaluation and control device (25) is adapted to the cause of the presence of a significant change in slope by comparing a measured in the significant change in slope hydraulic medium pressure indication value with at least one known, for the hydraulic-Dehnspanneinrichtungstyp characteristic setpoint for the hydraulic medium pressure indication value to determine.

70. Device (1) according to claim 69, characterized in that the setpoint value for the hydraulic medium pressure indication value is a hydraulic medium pressure indication value upon contact of the clamping surface (19) with a tool (20) or workpiece to be clamped and / or during a stop of Clamping screw (9) on a axial displacement of the clamping screw (9) limiting stop (10).

71. Device (1) according to one of claims 60 to 70, characterized in that the evaluation and control device (25) is adapted to a contact of the clamping surface (19) with an exciting tool (20) or workpiece as a cause to conclude for the presence of a significant change in slope and to conclude based on this cause on the achievement of a minimum clamping force as a clamping state.

72. Device (1) according to one of claims 60 to 71, characterized in that the evaluation and control device (25) is designed to:

to close a stop of the clamping screw (9) on a stop (10) delimiting the axial adjustment of the clamping screw (9) as the cause of the presence of a significant change in the inclination,

the hydraulic medium pressure indication value measured by the measuring device (23) in the case of the marked change in gradient with a previously known setpoint value for the hydraulic medium pressure indication value characteristic of the hydraulic expansion device type used in the case of a stop of the clamping screw (9) on an axial adjustment of the clamping screw (9) to compare limiting stop (10)

73. Device (1) according to one of claims 37 to 72, characterized in that the evaluation and control device (25) is adapted to check whether a predetermined shutdown condition is met, and a completion of a screwing of the clamping screw (9). effect if the test is positive.

74. Device (1) according to claim 73, characterized in that the predetermined switch-off condition a previously known, characteristic of the hydraulic Dehnspanneinrichtungstyp hydraulic medium pressure indication value at a stop of the clamping screw (9) on a axial displacement of the clamping screw (9) limiting stop (10).

75. Device (1) according to one of claims 37 to 74, characterized in that the signaling device (26) comprises a lamp, a loudspeaker, a display and / or a vibration device.