Device for heat treatment

Abstract

To provide a device for shrink chuck heat treatment.SOLUTION: In order to enable measurement of a shell temperature of a shrink chuck (4) as accurately as possible, a measuring / computing unit (14) includes: at least one temperature sensor (16) for detecting the shell temperature of the shrink chuck (4) disposed in receiving means (8); and a reflection sensor (62). The measuring unit is applied with a current (test pulse) before starting an actual heat treatment operation on the shrink chuck (4) inserted into a heat treatment unit (12). For the test pulse, a time / current curve is to be ascertained and an overall time / current curve ascertained for the test pulse is taken as a magnetic fingerprint for the shrink chuck (4) inserted into the heat treatment unit and an item of geometrical information for the shrink chuck (4) is ascertained by using the magnetic fingerprint.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus for heat treating, in particular induction heating or cooling, a shrink chuck for a shank tool, in particular a shrink-fit apparatus (for a shrink chuck) or a cooling apparatus or a shrink-fit apparatus with a cooling apparatus. The present invention further relates to a method for operating such an apparatus. [Background technology]

[0002] Such an apparatus for heat treating a shrink chuck, in this case a shrink-fit apparatus, is known from US Pat. No. 5,399,633. The shrink-fit apparatus detects the shell or surface temperature of the shrink chuck without contact and provides a sensor-type temperature measuring device, in this case a radiation / IR thermometer, arranged fixedly at a distance on the shrink-fit apparatus. However, for temperature measurement, the induction coil mechanism of the shrink-fit needs to be moved out of the range in which it engages with the shrink chuck, so that the shrink chuck surface can be sensed by the sensor. Temperature measurement during the heating operation is therefore not possible.

[0003] It has been sought to achieve an improvement in this respect by a further such shrink-fit device, known from DE 10 200 43 511 A1, which has an induction coil arrangement and a sensor-type temperature measuring device with contactless detection, in which a measuring channel extends through the induction coil arrangement and opens into a receiving opening for receiving the shrink chuck, which then provides a sensor-type temperature measuring device with contactless detection, which further comprises a temperature sensor, in this case also a radiation thermometer, for detecting the shell temperature of the shrink chuck, which temperature sensor engages in the measuring channel.

[0004] The radiation thermometers used in the prior art cited herein (for non-contact temperature measurements on a shrink chuck) operate on the basis of infrared / thermal radiation emitted from an object (such as infrared / thermal radiation emitted by the shrink chuck in this case).

[0005] Every body or object emits an amount of infrared or thermal radiation that corresponds to its surface temperature (this infrared or thermal radiation can be detected and evaluated using a radiation thermometer). The intensity of the infrared / thermal radiation varies depending on the temperature of the object.

[0006] However, in addition, the intensity of the infrared / thermal radiation of a "real object" also depends on the material and the surface, i.e. a (real) object radiates with a lower intensity than an ideal thermal radiator, i.e. an ideal "black body radiator", by a material / surface-dependent factor. This factor is known as the "emissivity ε".

[0007] Therefore, in the case of non-contact temperature measurement, if one wishes to accurately measure the temperature of individual objects, it is necessary to know the (individual) emissivity ε, i.e., thermal radiation capability, of each object.

[0008] This has turned out to be precisely a disadvantage in the case of known shrink-fit devices in which a radiation thermometer is used, which seeks to measure the temperature of a (multiple different) real object, i.e. a shrink chuck, which in fact has an unknown emissivity ε.

[0009] Therefore, radiation thermometers used are usually pre-set (or calibrated) for a specific emissivity ε, i.e. accurate temperature measurement is only possible for a very specific object with a very specific material / surface (specifically, the object whose material / surface has exactly the pre-set emissivity ε), resulting in measurement errors for all other objects (or shrink chucks) measured that have a different emissivity ε.

[0010] Furthermore, from (Patent Document 3) (Shrink-fit Apparatus with Heating Control) it is known to apply a current of known current magnitude, current type, frequency and duration (test pulse) to the induction coil of the induction shrink-fit apparatus before the start of the actual induction heating operation on a shrink chuck inserted in the induction coil, to ascertain the time / current curve of the shrink chuck inserted in the induction coil for this test pulse, and to take the overall time / current curve ascertained for the test pulse as a magnetic fingerprint of the shrink chuck inserted in the induction coil.

[0011] (Patent Document 3) further describes that the magnetic fingerprint or time / current curve identified for a shrink chuck inserted in an induction coil can be used to automatically determine what kind of shrink chuck is inserted in the induction coil (to heat it), and in particular, the shape of the shrink chuck inserted in the induction coil, and how to do so.

[0012] The document US Pat. No. 5,399,633 also presents a circuit capable of generating this test pulse in an induction coil.

[0013] The entire contents of (Patent Document 3) (Shrink-fit device with heat control) are incorporated into the subject matter of this application. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] German Patent Application Publication No. 10 2012 216 186 A1 [Patent Document 2] German Patent Application Publication No. 10 2018 121 883 A1 [Patent Document 3] European Patent No. 3 557 945 B1 [Patent Document 4] European Patent Application Publication No. 3 444 064 A1 [Patent Document 5] DE 199 15 412 [Patent Document 6] DE 10 2005 042 615 Summary of the Invention [Problem to be solved by the invention]

[0015] The object of the present invention is to improve shrink-fit devices known in the prior art, and known devices for heat-treating shrink chucks in general, with regard to temperature measurement on the shrink chuck being treated, and (thus) to ensure a reliable heat-treatment, in particular heating or cooling, of the shrink chuck, together with a high level of safety and easy handling. [Means for solving the problem]

[0016] Said object is achieved by an apparatus for heat treating, in particular for inductive heating or cooling, a shrink chuck and a method for operating such an apparatus having the features of the respective independent claims.

[0017] The dependent claims and the following description relate to advantageous refinements of the invention, which relate to both the device and the method.

[0018] Unless expressly defined otherwise, terms such as upper, lower, front, rear, left or right that may be used are to be understood in the normal manner and in light of the present drawings. When used and unless expressly defined otherwise, terms such as radial and axial are to be understood in relation to a central axis or axis of symmetry of a part / component described herein and in light of the present drawings.

[0019] When used, the term "substantially" may be understood to mean "substantially yet to a significant extent" (according to the understanding applied at the highest judicial level). Thus, possible deviations from the exact value that this term means may occur unintentionally (i.e. without any functional basis), due to manufacturing or assembly tolerances, etc.

[0020] An apparatus for heat treating, in particular induction heating or cooling, a shrink chuck for a shank tool, in particular a shrink fit device (for a shrink chuck), or a cooling device, or a shrink fit device with a cooling device, has a receiving means forming a receiving area for the shrink chuck, in particular a receiving opening for receiving the shrink chuck, has a heat treatment unit, in particular an induction coil mechanism or a cooling unit, surrounding the receiving means or receiving area concentrically, in particular with respect to a central axis, and has a measuring / calculating unit, in particular for non-contact temperature measurement of the shrink chuck.

[0021] Here, a "... unit", such as a measurement / calculation unit, may in particular comprise a processor, a memory unit, an interface and / or also operating, control and calculation programs, which are in particular stored in the memory unit and serve in particular for execution, for controlling the measurement sensor and also for evaluating the measurements.

[0022] Furthermore, in the case of the device according to the invention, the measuring / calculating unit is adapted to have at least one temperature sensor for non-contact detection of the shell temperature of the shrink chuck, in particular arranged in the receiving means, and a reflection sensor, in particular an infrared reflection sensor, arranged around the receiving means or the receiving opening.

[0023] Such reflective sensors have proven to be particularly advantageous in this respect, since they can also be used to ascertain the surface condition of the object (e.g. matt, glossy or emissivity ε) and the presence of the object itself, in particular the presence of a shrink chuck inserted within the heat treatment unit, in particular the induction coil mechanism, as is the case here.

[0024] The measurement / calculation unit is A current (test pulse) of known current magnitude, current form, frequency and duration can be or is applied to the heat treatment unit, in particular the induction coil mechanism, before the start of an actual heat treatment operation, in particular a cooling operation or an induction heating operation, on a shrink chuck inserted in the heat treatment unit, in particular the induction coil mechanism, For this test pulse, a time / current curve of a shrink chuck inserted in a heat treatment unit, in particular an induction coil mechanism, can be or is determined, and the overall time / current curve determined for the test pulse can be or is taken as a magnetic fingerprint of a shrink chuck inserted in a heat treatment unit, in particular an induction coil mechanism, Using the magnetic fingerprint, items of geometric information, in particular the outer diameter, of a shrink chuck inserted in a heat treatment unit, in particular an induction coil mechanism, can be ascertained or are ascertained, A reflection measurement can be or is performed by a reflection sensor (62) on the heat treatment unit (12), in particular on the shrink chuck (4) inserted in the induction coil mechanism (12), and can be or is performed by a reflection sensor (62) on the heat treatment unit (12), in particular on the shrink chuck (4) inserted in the induction coil mechanism (12), and can be or is corrected using an item of geometric information (correction value 1), and It is further configured that a temperature measurement can be or is performed and corrected or is corrected by a temperature sensor (16) on the heat treatment unit (12), in particular on the shrink chuck (4) inserted in the induction coil mechanism (12), using the reflection measurement and the items of geometrical information or using a corrected reflection measurement (correction value 2).

[0025] The shell temperature or the resulting shell temperature of a shrink chuck inserted in the heat treatment unit, in particular the induction coil mechanism, can then be ascertained from the corrected temperature measurement, or the measurement / calculation unit may be further configured such that the shell temperature or the resulting shell temperature of a shrink chuck inserted in the heat treatment unit, in particular the induction coil mechanism, can be ascertained or subsequently ascertained from the corrected temperature measurement.

[0026] The method of operating the device according to the invention, in particular the shrink-fit device according to the invention, comprises the steps of: A current (test pulse) of known current magnitude, current form, frequency and duration is applied to the heat treatment unit, in particular the induction coil mechanism, before the start of an actual heat treatment operation, in particular a cooling operation or an induction heating operation, on a shrink chuck inserted in the heat treatment unit, in particular the induction coil mechanism, For this test pulse, a time / current curve of a shrink chuck inserted in a heat treatment unit, in particular an induction coil mechanism, is ascertained, and the overall time / current curve ascertained for the test pulse is taken as a magnetic fingerprint of the heat treatment unit, in particular a shrink chuck inserted in the induction coil mechanism, Using the magnetic fingerprint, items of geometric information, in particular the outer diameter, of the shrink chuck inserted in the heat treatment unit, in particular the induction coil mechanism, are identified; A reflection measurement is performed by a reflection sensor (62) on the heat treatment unit (12), in particular on the shrink chuck (4) inserted in the induction coil mechanism (12), and a reflection measurement is performed and corrected by the reflection sensor (62) on the heat treatment unit (12), in particular on the shrink chuck (4) inserted in the induction coil mechanism (12), in particular using an item of geometric information (correction value 1); Using the reflection measurement and an item of geometrical information, or using a corrected reflection measurement (correction value 2), a temperature measurement is performed and corrected by a temperature sensor (16) on the heat treatment unit (12), in particular on the shrink chuck (4) inserted in the induction coil mechanism (12).

[0027] In simplified exemplary terms, in one case a reflectance sensor corrected using an item of geometric information corrects a temperature sensor, and in another case the temperature sensor is corrected using a "pure" / uncorrected reflectance sensor signal and an item of geometric information.

[0028] Here, "corrected" may be understood to mean that what is corrected is ascertained taking into account or using what has been (previously) ascertained.

[0029] Now, by way of example and in simplified or exemplary terms, it is possible to take into account items of geometric information, in particular the outer diameter of the shrink chuck, in a reflection measurement or when ascertaining a reflection or in a temperature measurement or when ascertaining a temperature.

[0030] In other words, in a reflectance measurement or when ascertaining a reflectance or in a temperature measurement or when ascertaining a temperature, items of geometrical information are taken into account, or again in other words, the result of the reflectance measurement or the result of the temperature measurement depends on the items of geometrical information.

[0031] Accordingly, for example, in simplified or exemplary terms, it is therefore also possible here to take into account, for a corrected reflectance measurement or the result of a corrected reflectance measurement, in the temperature measurement or when ascertaining the temperature or shell temperature, or, for an uncorrected reflectance measurement, to take into account items of geometric information, in particular the outer diameter of the shrink chuck, in the temperature measurement or when measuring the temperature or shell temperature.

[0032] In other words, the corrected reflectance measurement or the result of the corrected reflectance measurement is taken into account in the temperature measurement or when ascertaining the (shell) temperature, or the uncorrected reflectance measurement and the items of geometric information are taken into account in the temperature measurement or when ascertaining the (shell) temperature (thus directly and not via the corrected reflectance measurement).

[0033] "Taking into account" may also mean incorporating "correction terms," ​​"correction factors," and / or "correction values" that correspond to a mathematical rule or algorithm applied in this regard.

[0034] This may be done, for example, by using reflectance measurements from a reflectance sensor to calibrate / set or (pre)set at least one temperature sensor, or by using measurements from the reflectance sensor to determine, in particular, how the resulting shell temperature is determined from measurements from the temperature sensor.

[0035] The item of geometrical information may be, for example, the outer diameter of the heat treatment device, in particular the shrink chuck inserted in the induction coil mechanism, or other geometrical data describing the heat treatment device, in particular the shrink chuck inserted in the induction coil mechanism, such as material or wall thickness, length, etc., or simply material parameters.

[0036] Such a preferably contactless measuring temperature sensor may for example be a sensor based on the measurement of (thermal) radiation from an object. It may for example be a radiation sensor, such as a pyrometer or ratio pyrometer.

[0037] Such a reflective sensor may be, for example, an infrared reflective sensor.

[0038] In particular, it may be advantageous to use a number of temperature sensors arranged around the receiving means or receiving area, or at least one temperature sensor arranged around the receiving means or receiving area, in particular inclined with respect to the central axis, for non-contact detection of the shell temperature or surface temperature of a shrink chuck arranged in the receiving means / receiving area, whereby advantageously such a temperature sensor may further be made to be a radiation detector or radiation sensor.

[0039] In other words, it is very advantageous if each of the plurality of temperature sensors and / or gradient temperature sensors is or is configured as a radiation detector, in particular a pyrometer with a radiation detector, for detecting thermal radiation from a shrink chuck arranged in the receiving means.

[0040] The tilt angle of the tilted temperature sensor is preferably 30° to 60°, and particularly preferably 45°.

[0041] The inclination of the sensor allows for better detection of the surface by its emissivity ε, especially in areas where surface temperature measurement and / or monitoring is desired, for example in the range of 50°C to 70°C.

[0042] Furthermore, by tilting the temperature sensor, it is possible to achieve a larger detectable area that can be monitored by the temperature sensor.

[0043] In particular it may be advantageous if at least the temperature sensors and / or the gradient temperature sensor or one of them is provided with a focusing device and / or a shielding means, in particular a diaphragm.

[0044] In this way or by using such focusing and / or shielding means, it is possible to achieve insensitivity of the temperature sensor to stray radiation from devices emitting thermal radiation, e.g. shrink-fit devices, arranged in close proximity to the temperature sensor, and therefore additional shielding means for the temperature sensor can be omitted if necessary.

[0045] Then, further, when at least two, in particular a plurality of, temperature sensors are used in the apparatus, said temperature sensors may be adapted to be used jointly to measure the shell temperature or surface temperature of a shrink chuck arranged in the receiving means / receiving area.

[0046] "Used" may mean that in particular at least two, in particular a plurality of temperature sensors or measurements / measured values ​​thereof are used to ascertain the resulting shell or surface temperature.

[0047] In this regard, in case of multiple temperature sensors, a first simple approach may be to determine the average value of the temperature sensors or their measurements / measured values ​​as the resulting shell temperature, where each individual temperature sensor or its measurement / measured value may also be weighted individually.

[0048] Thus, here, in case of multiple temperature sensors, it may further be provided that at least two, in particular some or all, of the temperature sensors have different configurations / measurement settings.

[0049] "Different configurations / measurement settings" (in the case of temperature sensors) may be understood to mean in particular that the temperature sensors are differently / calibrated for different materials / surfaces (or different emissivities ε) of, for example, the shrink chuck. This may also mean that the temperature sensors have measurement ranges in different wavelength ranges (see ratio pyrometers).

[0050] In other words, different calibrations / settings, in particular different emissivities ε, may be set for the multiple temperature sensors and the measurements from the multiple temperature sensors may be compared and / or jointly processed and a resulting shell temperature may be determined therefrom.

[0051] However, there may also be mathematical advantages here in particular in that the emissivity ε can be eliminated if the measurements by several temperature sensors are set in relation to one another.

[0052] Alternatively, rather than using multiple temperature sensors with different configurations / measurement settings, it may be possible to evaluate the signal of one temperature or radiation sensor used in a different way, for example based on different emissivities ε.

[0053] Temperature measurement is improved especially if the sensors are placed around the periphery / receiving area of ​​the receiving means or around the opening.

[0054] In one refinement, the sensors can be arranged in or around the receiving means / receiving area in a circle relative to the central axis (if appropriate in different circular groups) and / or at different axial heights relative to the central axis, which can be done with a uniform pitch or with a non-uniform pitch.

[0055] Here, each sensor can be fixed individually at a predefined position, for example in or on the heat treatment unit or on its housing, or a common holding device can be provided, for example an annular structural unit (measuring ring) which at least partially surrounds the receiving means / receiving area, which holding device or structural unit receives the sensor and is then installed in the device or in or on the heat treatment unit / housing.

[0056] Here, the substantially annular structural unit or measuring ring may preferably be arranged coaxially relative to a central axis within the apparatus, in particular axially adjacent to a heat treatment unit, in particular an induction coil arrangement or a cooling unit.

[0057] It may also be advantageous to arrange sensors of the same type adjacently within a substantially annular structural unit, for example "bundled" in a (circular) segment. For example, temperature sensors may be arranged adjacent to one another in one circular segment of a substantially annular structural unit or measuring ring.

[0058] In one refinement, the thermal treatment unit and / or the housing of the thermal treatment unit may have or extend through at least one or more recesses, for example (measurement) channels that open into the receiving area formed by the receiving unit and are in particular radial, in which recess or channel or in which recess or channel the sensor, or in each case one of the sensors, is arranged.

[0059] In the case of an induction coil mechanism as a heat treatment unit, it may be advantageous especially if the coil winding of the induction coil mechanism is wound around an associated recess or an associated channel so as to leave the associated channel free.

[0060] A sensor, such as a temperature sensor and / or a reflection sensor, may then be positioned or inserted in such a (measurement) channel or at least partially in such a measurement channel and / or in such a (measurement) channel, in particular such that the sensor performs a measurement through the measurement channel.

[0061] If the sensor is furthermore arranged outside the housing of the thermal treatment unit, it is advantageous if the housing provides a corresponding opening for the sensor, through which the sensor can perform a measurement.

[0062] In particular, it is advantageous from a measurement perspective if such a measurement channel extends substantially radially with respect to a central axis through the thermal treatment unit and / or its housing.

[0063] In one refinement, such a measurement channel may be arranged in the axially central region of the induction coil arrangement, preferably approximately centrally between its axial ends.

[0064] Furthermore, it has proven advantageous to insert a preferably replaceable protective window, which is in particular permeable to thermal radiation, into such a measuring channel, in particular to protect the sensor against contamination and / or damage.

[0065] In this respect, instead of or in addition to a winding (measurement) channel, in the case of an induction coil arrangement as a heat treatment unit, it can be provided that the induction coil arrangement has two or more mutually spaced partial coils, whereby the or the sensor is arranged in the space between the partial coils (through which measurements can be performed) according to the channel arrangement. This can also be provided correspondingly in the case of a cooling unit with a partial unit as a heat treatment unit.

[0066] Furthermore, the measured values ​​may be transmitted from the temperature sensor and / or the reflection sensor to a measurement / calculation unit by wire or wirelessly.

[0067] It is also advantageous if the device comprises a control unit, which may serve, in particular, to control a heat treatment unit, such as an induction coil mechanism or a cooling unit, for example such that the control unit controls the power of the heat treatment unit, for example the supply of current to the induction coil mechanism, based on the shell temperature ascertained using the sensor.

[0068] Additionally, the ascertained shell temperature may be (simply and exclusively) used to detect the temperature state of the shrink chuck, i.e., simply and illustratively, the ascertained shell temperature may be used to identify whether there is an already heated shrink chuck in the apparatus, and if so, what its shell temperature is.

[0069] In such a case, the controller may not, for example, initiate a heating operation (at all) if the shrink chuck is already (too) hot.

[0070] It may further be advantageous if the device comprises an indication means for indicating the thermal state, in particular the thermal state of a tool receptacle, in particular a shrink chuck, arranged in the receiving means / receiving area. Said indication means may for example be a coloured diode. Different colours may indicate different thermal states.

[0071] Preferably, operation of the shrink fit apparatus according to the invention includes the shrink chuck being inductively heated, and thus expanded, within a receiving means surrounded by a heat treatment means configured as an induction coil arrangement, the resulting shell temperature being used to control the heating operation, and in particular the heating operation may be automatically stopped when a specified temperature is reached.

[0072] Alternatively, it may involve the shrink chuck being cooled in a receiving means surrounded by a heat treatment device configured as a cooling unit, and the resulting shell temperature being used to control the cooling operation.

[0073] The control may for example involve the supply of electrical current to the heat treatment unit being varied or adapted and / or controlled based on the resulting shell temperature.

[0074] Starting from the problem that in the case of several shrink chucks whose temperatures are to be measured, the emissivity ε is different and unknown, the invention is based on the consideration that when using (radiation) sensors for temperature measurement, it may or should be necessary to know the specific emissivity ε of the associated (individual) shrink chuck (for an accurate temperature measurement / determination), and therefore the (radiation) sensor needs to be set (if computationally appropriate) for said emissivity ε individually in each case and the (radiation) sensor needs to be calibrated individually for each shrink chuck.

[0075] To remedy this, the present invention provides for a reflective sensor or reflective measurements to be made on the shrink chuck to be measured, placed in the receiving means, which is (or can be) used to ascertain information specific to the shrink chuck placed in the receiving means, such as its individual emissivity ε, which is then used to make a (corrected) temperature measurement.

[0076] However, it has been recognized that the reflection measurement is also influenced by the distance between the reflection sensor and the shrink chuck or the shrink chuck surface / shell, which distance also depends on the shape of the shrink chuck placed in the receiving means, in particular its outer diameter, and the invention provides a method for automatically obtaining items of geometrical information in this regard, in particular the outer diameter of the shrink chuck placed in the receiving means.

[0077] According to the invention, this is done using an (individual) magnetic fingerprint or by ascertaining the (individual) magnetic fingerprint of the (individual) shrink chuck placed in the receiving means, which magnetic fingerprint is then used or can subsequently be used to ascertain or obtain an item of geometric information specific to the shrink chuck placed in the receiving means, such as the individual outer diameter.

[0078] Using this item of geometrical information, a reflectance measurement can then be made and corrected (reflection measurement corrected using correction value 1) and the corrected reflectance measurement can then be used to make and correct a temperature measurement (temperature measurement corrected using correction value 2).

[0079] Alternatively, it is also possible to take the geometrical information directly into account, in which case it is taken into account together with the uncorrected reflection measurement in the temperature measurement, which is then performed.

[0080] In the present invention, this means that no additional distance sensors are required, which may be necessary especially due to the spacing between the reflective sensor and the shrink chuck or shrink chuck surface / shell.

[0081] It has been found to be a further particular advantage of the invention that it can be automated, since the entire invention can be carried out automatically by means of a corresponding control program for the measurements and calculations of the sensors.

[0082] Thus, the present invention is distinguished by its simplicity, efficiency and effectiveness.

[0083] The above description of advantageous embodiments of the present invention includes a number of features which are partially combined with one another in the respective dependent claims. However, these features can also be advantageously combined to form further combinations which, considered individually, are meaningful.

[0084] When certain terms are used in the specification or claims in the singular or in combination with a number, the scope of the invention is not intended to be limited to the singular or the number associated with said term. Furthermore, the words "a" or "an" should be understood as indefinite articles and not as numbers.

[0085] The above-mentioned characteristics, features and advantages of the present invention and the manner in which they are achieved will be more clearly and more easily understood in connection with the following description of exemplary embodiments of the present invention, which are discussed in more detail in conjunction with drawings / figures (wherein identical parts / components and functions are indicated by identical reference symbols in the drawings / figures).

[0086] The exemplary embodiments serve to explain the invention and do not limit the invention to the combination of features described therein, which also applies to functional features. Moreover, preferred features of each exemplary embodiment may be independently removed from the exemplary embodiment and introduced into another exemplary embodiment to complement the same, and may be explicitly considered in combination with any of the claims. [Brief description of the drawings]

[0087] [Figure 1] 1 illustrates a shrink-fit device having an induction coil mechanism equipped with multiple non-contact measurement temperature sensors and reflective sensors according to one embodiment. [Diagram 2] 2 shows a perspective view of an induction coil mechanism of the shrink-fit device according to FIG. 1; [Diagram 3] 2 is a radial section through an induction coil mechanism of the shrink-fit device according to FIG. 1; [Figure 4] 2 is an axial section through an induction coil mechanism of the shrink-fit device according to FIG. 1; [Diagram 5] FIG. 1 illustrates a perspective view of a shrink fit device including a cooling device with a measurement ring assembled within the cooling device, according to one embodiment. [Figure 6]FIG. 6 shows a side view of the shrink-fit device according to FIG. 5 with the cooling device and with the measuring ring installed in the cooling device. [Figure 7] 6 shows a measuring ring of the shrink-fit device according to FIG. 5 in a perspective view. [Figure 8] 6 is a schematic diagram showing the function of the measuring ring of the shrink-fit device according to FIG. 5; [Figure 9a] FIG. 13 shows a further measuring ring. [Figure 9b] FIG. 13 shows a further measuring ring. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0088] Shrink-fit device with non-contact temperature measurement (Figs. 1 to 4) FIG. 1 shows a portion of a shrink fit apparatus 2 for shrink fitting 120 a shank tool 6 or (as shown) a milling tool 6 onto or off of a shrink chuck 4, specifically showing an induction coil mechanism 12 having a plurality of non-contact measurement temperature sensors 16 and having a reflective sensor 62.

[0089] 2-4 show the induction coil mechanism 12 in detail in various views / sections.

[0090] As shown in FIG. 1, for the purpose of shrink fitting or removal 120, the shrink fitting device 2 comprises an induction coil mechanism 12 which is longitudinally movable along its coil axis 10 and serves to inductively heat 120 the shrink chuck 4 (see in particular FIGS. 2 to 4 ), a control unit 28 (shown diagrammatically) for controlling 160 the operation on or heating of the shrink chuck 4, and a measurement / calculation unit 14 for performing and evaluating measurements made by the temperature sensor 16 and / or the reflection sensor 62.

[0091] In this case, the shrink chuck 4 shown in FIG. 1 comprises as sleeve portion 32 a cylindrical hollow clamping area 34 accessible via an end opening 36 provided at the front end 38 of the shrink chuck 4 for inserting a tool or milling cutter shank 40.

[0092] The clamping area 34 of the shrink chuck 4 has a nominal diameter somewhat smaller than the tool shank 40, so that the tool shank 40 can be clamped in a manner known per se by (induction) heating 120 of the shrink chuck 4. In the shrink fit state, the tool or milling cutter shank 40 is rotatably held together by a frictional interference fit for the purpose of transmitting torque to the front working part 42 of the rotary tool 6.

[0093] Similarly, for removal, only the shrink chuck 4 is heated 120 on one side until thermal expansion again releases the tool or milling cutter shank 40 for removal purposes.

[0094] As shown in FIGS. 1 to 4, the induction coil mechanism 12 surrounds the receiving opening 8 of the shrink chuck 4 concentrically about its coil axis 10.

[0095] The shrink chuck 4 is brought into a desired heating position relative to the induction coil mechanism 12 by axially moving the induction coil mechanism 12 along its coil axis 10 (see FIG. 1). For this purpose, it is also possible to provide a stop element on the induction coil mechanism, e.g. a pole disc.

[0096] To generate the electromagnetic alternating magnetic field, the induction coil arrangement 12 includes a coil winding 24 within the coil housing 18, as can be seen particularly in FIGS.

[0097] In order to be able to detect the shell temperature of the shrink chuck 4 during the heating operation 120, a number of measurement channels 22, in this case six, each opening into the receiving opening 8, extend through the induction coil arrangement 12 in a radial direction relative to the coil axis 10.

[0098] 3 and 4, the six measurement channels 22 are arranged in an axial central region 44 of the induction coil arrangement 12 between their axial ends at a substantially uniform pitch about the coil axis 10 and at the same axial height with respect to the coil axis 10, and the coil windings 24 are wound around the six measurement channels 22 to leave them free. The coil-side inner portion 46 of each measurement channel 22 aligns with an opening 26 in an outer wall 48 of the induction coil housing 50 (so that there are also a total of six openings in the outer wall 48 of the induction coil housing 50).

[0099] In five of the six openings 26 of the induction coil housing 50 is inserted in each case one non-contact measurement temperature sensor 16, in this case a radiation detector 16 (or optionally a pyrometer 30) that measures thermal radiation (non-contact) and detects the thermal radiation emitted by the shrink chuck 4 through its respective measurement channel 22 of the coil winding 24. In the sixth of the six openings 26 of the induction coil housing 50 is inserted an infrared reflection sensor 62, which likewise performs a reflection measurement (relative to the shrink chuck 4) through its measurement channel 22 in the coil winding 24.

[0100] The control unit 28 and the measurement / calculation unit 14 are coupled on the input side by a cable 52 to the temperature sensor 16 and the reflection sensor 62 and thus receive their measurement signals which are jointly processed 140 in the measurement / calculation unit 14 to give the resultant shell / surface temperature of the measured shrink chuck 4.

[0101] A shrink fit operation can then be performed on the shrink chuck 4 by the control unit 28 based on the ascertained resultant shell / surface temperature of the measured shrink chuck 4 .

[0102] Here, during heating 120 of the shrink chuck 4, (automatic) temperature control can be performed based on the ascertained resultant shell temperature, for example by the control unit 28 influencing 160 the supply of current to the induction coil mechanism in dependence on the resultant shell temperature.

[0103] To ascertain the resulting shell / surface temperature by the temperature sensor 16 and the reflective sensor 62, the following method is provided.

[0104] First, in a method initiated by the measuring / calculating means 14, a test pulse, i.e., a current of known current magnitude, current type, frequency and duration, is applied to the induction coil mechanism 12 prior to the start of the actual heat treatment operation on the shrink chuck 4 inserted within the induction coil mechanism 12.

[0105] For this test pulse, the time / current curve of the shrink chuck 4 inserted in the induction coil mechanism 12 is ascertained. The overall time / current curve ascertained for the test pulse is taken as the magnetic fingerprint of the shrink chuck 4 inserted in the induction coil mechanism 12.

[0106] The magnetic fingerprint is then used to ascertain an item of geometric information of the shrink chuck 4 inserted in the induction coil arrangement 12, for example in this case the outer diameter.

[0107] Furthermore, a reflection measurement is performed by the reflection sensor 62 on the shrink chuck 4 inserted in the induction coil mechanism 12, and the reflection measurement by the reflection sensor 62 is corrected using an item of geometric information (correction value 1).

[0108] The corrected reflectance measurement (Correction 2) is then used to make and correct a temperature measurement by temperature sensor 16.

[0109] The resulting shell temperature of the shrink chuck 4 is then ascertained from the temperature measurement corrected by the temperature sensor.

[0110] Shrink-fit machine with cooling device and non-contact temperature measurement (Figs. 5 to 8) Figures 5 and 6 show a shrink-fit apparatus 2 having a cooling device 12 as shown and described in detail in Patent Document 4 (see Figures 1 and 4 of Patent Document 4 and

[0014] to

[0026] ), the contents of which are incorporated herein by reference.

[0111] As shown in FIG. 5 (see also FIG. 4 of JP 2003-233663 A) and FIG. 6 (see also FIG. 1 of JP 2003-233663 A), the cooling device 12 has a cooling head 72 movably guided on a frame or column 70 and equipped with a cooling attachment 74, which can be mounted on at least the part of the shrink chuck 4 to be cooled. The cooling attachment 74 has a receiving opening 8 (see passage opening 6 of JP 2003-233663 A) whose inner contour / diameter is adapted to the outer contour / diameter of the part of the shrink chuck 4 to be cooled (not shown) so that the cooling attachment 74 can be pressed / mounted on the shrink chuck 4 to be cooled.

[0112] For further details regarding the shrink-fit device 2 and its cooling device 12, please refer to (Patent Document 4) (see Figs. 1 and 4 and

[0014] to

[0026] of (Patent Document 4)).

[0113] As also shown in Figures 5 and 6, a measurement ring or sensor ring 56 (see Figure 7, alternative sensor rings are shown in Figures 9a and 9b) opening on a particular circular ring segment can be integrated into the cooling attachment 74 and used for non-contact measurement of the shell temperature of the cooling attachment 74 or of the shrink chuck 4 received in its receiving opening 8. This integration, in particular at the lower end of the cooling attachment 74, ensures that the measurement ring 56 (see Figure 7) is arranged coaxially (by its central axis 58) with respect to the central axis 10 of the cooling head 72 or cooling attachment 74.

[0114] Here, the inner diameter of the measuring ring 56 is substantially equal to the inner diameter of the cooling attachment 74 (at its lower end), so that said measuring ring becomes part of the receiving opening 8 .

[0115] FIG. 7 shows measurement ring 56 in detail with a cut-away "upward" view, providing a view into housing 76 of measurement ring 56.

[0116] As shown in FIG. 7, the measurement ring 56 is a generally closed annular body having an opening at which two ring arms 88, 90 are positioned opposite each other.

[0117] As also shown in FIG. 7, various types of sensors 60, 16, 62 are accommodated in a measuring ring housing 76 forming the body of the measuring ring 56, in particular three adjacently arranged infrared temperature sensors 16 are accommodated in a left hand arm 88 of the measuring ring 56 illustrated in FIG. 7, and further infrared temperature sensors 60, 16 (comprising a transmitter 78 and a receiver 80) and a reflection sensor 60, 62 are accommodated in a right hand arm 90 of the measuring ring 56 illustrated in FIG. 7.

[0118] All these sensors 60, 16, 62 are received in the measuring ring 56 or in its housing 76 such that the measurement direction of each of said sensors is directed radially towards the central axes 58, 10. To this end, the measuring ring housing 76 also provides radially inner passages or openings 92 in which the sensors 60, 16, 62 located can perform measurements in the radially inward direction.

[0119] In an embodiment not shown, the sensors 60, 16, 62 may also be oriented substantially perpendicular to the outer shell of the shrink chuck 4, which is often cone-shaped.

[0120] Via lines (not shown), the sensors 60, 16, 62 are connected to a microcontroller 86, which is likewise accommodated in the measuring ring 56 or its housing 76 (having a measurement / calculation unit 14 for carrying out and evaluating the measurements made by the temperature sensor 16 and the reflection sensor 62), so that measurement signals from the sensors 60, 16, 62 can be supplied to said microcontroller to be processed in order to ascertain 140 the resulting shell temperature of the shrink chuck 4, which in this case is accommodated in the cooling attachment 74.

[0121] The microcontroller 86 is connected via a supply line 84 to the controller 28 of the cooling device 12, controller 28 for short, which sends its signals such as the resultant shell temperature. The controller 28 can then control 160 the cooling operation 120 (for the shrink chuck 4 received in the cooling attachment 74) in a manner that depends on the currently ascertained shell temperature.

[0122] As also shown in FIG. 7, the measurement ring 56 provides an LED (thermal) status display 64 in the form of two colored LEDs 82, 94 located on the ends of two arms 88, 90 and thus visible to the user, one of which is a red LED 82 and the other a green LED 94, which are also connected to and controlled by the controller 28 via the microcontroller 86.

[0123] The illuminated green LED 94 indicates, for example, a thermal state of the shrink chuck 4 that has been cooled to such an extent that it can be safely touched by bare hands, and the illuminated red LED 82 indicates a thermal state of the shrink chuck 4 that is not yet (sufficiently) cooled. The flashing red light of the red LED 82 indicates an active cooling operation by the cooling means 12.

[0124] FIG. 8 illustrates the function 100 and interaction 200 and control 160 of the various sensors 60 , 16 , 62 during measurement or confirmation 140 of the shell / surface temperature of a shrink chuck 4 cooled by refrigeration or received within a cooling attachment 74 .

[0125] The measuring ring 56 or its sensors 60, 16, 62 (and light-emitting diodes 82, 94) are activated or switched into an activated state (1) as soon as the cooling attachment 74 with which the measuring ring 56 is integrated is moved from above downward over the shrink chuck 4 to be cooled, (2) during the cooling operation 120 in which the shrink chuck 4 is received within the cooling attachment 74 (and cooled in a manner controlled by the controller 28 (Note: the controller 28 optionally uses the confirmed surface temperature or surface color of the shrink chuck 4 to set cooling parameters such as cooling duration)), and (3) until the cooling attachment 74 with which the measuring ring 56 is integrated is fully lifted by being pushed upward from the shrink chuck 4 (this is collectively referred to as, for example, the "measurement phase" / "measurement cycle").

[0126] The start and end of the measurement or measurement phase ((1)-(3)) can be (automatically) confirmed by a reflective sensor 62, which identifies 220 whether the shrink chuck 4 is located within the measuring ring 56 by a simple reflective measurement.

[0127] During temperature measurement or temperature verification 140 (performed and controlled by the measurement / calculation unit 14), a test pulse, i.e. a current of known magnitude, current type, frequency and duration (test pulse), is applied to the shrink chuck before the actual cooling operation begins.

[0128] For this test pulse, the time / current curve is checked and the overall time / current curve is taken as the magnetic fingerprint of the shrink chuck 4.

[0129] Using the magnetic fingerprint, an item of geometric information of the shrink chuck 4 is ascertained, in this case the outer diameter.

[0130] Additionally, reflective measurements are made of the shrink chuck using reflective sensor 62 to ascertain items of reflective information such as the emissivity of the shrink chuck.

[0131] A temperature measurement of the shrink chuck is then carried out using the temperature sensor 16, the item of geometrical information, i.e. the outer diameter, and the item of reflective information, i.e. the emissivity, being taken into account in each case.

[0132] The resulting shrink chuck shell temperature can then be calculated from the temperature measurements, for example by averaging.

[0133] Then, based on the thus ascertained surface / shell temperature of the shrink chuck 4 located within the measuring ring 56, the cooling 120 is controlled 160 and the LED (thermal) status indicator light emitting diodes 82, 94, 64 are activated 160 in response to the ascertained surface / shell temperature.

[0134] Specifically, (1) when the cooling attachment 74 with the cooling ring 56 is first pressed against the top of the (hot) shrink chuck 4 to be cooled, the red light emitting diode 82 can be controlled to illuminate red to indicate a high temperature condition of the shrink chuck 4 or its surface / shell.

[0135] Next, when the cooling attachment 74 is pressed completely onto the shrink chuck 4 and the cooling operation 120 is started (2), the red light emitting diode 82 flashes during the cooling operation 120 to indicate “cooling” 120 .

[0136] When the cooling operation 120 is completed and the cooling attachment 74 is pulled upward (3), the red light-emitting diode 82 lights up if the shrink chuck 4 is still too hot, and the green light-emitting diode 94 lights up if the shrink chuck 4 has cooled sufficiently. If the red light-emitting diode 82 indicates that the shrink chuck 4 is still too hot, the cooling attachment 74 can be pushed down again below the shrink chuck 4 to perform a further cooling operation 120.

[0137] If desired, the entire cooling operation 120 can be automatically coupled to the temperature check 140 and controlled 160 based thereon.

[0138] It is further pointed out that a measuring ring 56 corresponding to the measuring ring 56 described above may also be arranged in the induction coil mechanism 12 of the shrink-fit device 2 in order to measure the shell temperature of the shrink chuck 4 received in the receiving opening 8 of the induction coil mechanism 12 (see Figs. 1-4). A measuring ring 56 corresponding to the measuring ring 56 described above may also be arranged in a separate cooling device 12 operating independently or separately.

[0139] Figures 9a and 9b show an alternative measuring ring 56 which may or may be used similarly in terms of its functionality and which may be integrated into the cooling attachment 74, in an overall view in Figure 9a and in a detailed view in which it is cut "upwards" in Figure 9b.

[0140] As shown in FIG. 9a, the measuring ring 56 is also a substantially closed annular body with an opening in which two ring arms 88, 90 are positioned opposite each other.

[0141] As also shown in Figure 9a (and in more detail in Figure 9b), the (single) temperature sensor 60, specifically the infrared temperature sensor 16', is received in a measurement ring housing 76 forming the body of the measurement ring 56, specifically the left hand arm 88 of the measurement ring 56 illustrated in Figure 9a. The reflective sensor 62, as shown diagrammatically, is received in a right hand arm 90 of the measurement ring 56 illustrated in Figure 9a.

[0142] Notwithstanding this, holding devices other than the measuring ring 56 may also be provided for the temperature sensor 16'.

[0143] The temperature sensor 60 or 16 ′ is equipped with a diaphragm 54 .

[0144] In contrast to the measuring ring 56 described above (according to FIG. 7), this temperature sensor 60 or 16 ′ is received in a measuring ring housing 76 so as to be inclined at an angle α of approximately 45° with respect to the central axis 10 .

[0145] Via lines (not shown), the temperature sensor 60 or 16' and the reflection sensor 62 are likewise connected to a microcontroller 86 (and having an invisible measurement / calculation unit 14) which is received in the measuring ring 56 or its housing 76, so that measurement signals from the temperature sensor 60 or 16' and the reflection sensor 62 can be supplied to said microcontroller to be processed in order to ascertain 140 the shell temperature of the shrink chuck 4, which in this case is received in particular in the cooling attachment 74.

[0146] The microcontroller 86 is connected (invisibly) via a supply line 84 to the controller 28 of the cooling device 12, controller 28 for short, said microcontroller transmits its signals, such as the shell temperature.

[0147] The controller 28 can then control 160 the cooling operation 120 (for the shrink chuck 4 received within the cooling attachment 74) in a manner that is dependent on the current shell temperature.

[0148] As also shown in FIG. 9a, the measurement ring 56 provides an LED (thermal) status display 64 in the form of two colored LEDs 82, 94 located on the ends of two arms 88, 90 and thus visible to the user, one of which is a red LED 82 and the other a green LED 94, which are likewise connected to and controlled by the controller 28 via the microcontroller 86.

[0149] The illuminated green LED 94 indicates, for example, a thermal state of the shrink chuck 4 that has been cooled to such an extent that it can be safely touched by bare hands, and the illuminated red LED 82 indicates a thermal state of the shrink chuck 4 that is not yet (sufficiently) cooled. The flashing red light of the red LED 82 indicates an active cooling operation by the cooling means 12.

[0150] The subject matter or contents of (Patent Document 3), which is also incorporated in the subject matter of the present application: The invention relates to a shrink-fit device according to the preamble of claim 1.

[0151] Prior Art Shrink-fit devices for shrink-fitting tool shanks into and out of tool holders have been known for some time. Originally, such shrink-fit devices were operated using gas burners or hot air and were used to heat a sleeve portion of the tool holder to expand the tool shank to a degree that it could be received in an interference fit or to release said tool shank. More recently, there has been an increase in the use of shrink-fit devices that use induction coils to heat the associated tool holder. This greatly accelerates the shrink-fit process, making it more efficient and easier to manage, thus contributing to its more widespread use.

[0152] A first shrink-fit device suitable for practical application is described in patent document DE 10 2004 03 13 5.1.

[0153] Currently known shrink-fit devices are still not optimally automated. Errors can occur, such as the sleeve part of the tool holder being induction heated for an excessively long time. This can result in the sleeve part of the tool holder being overheated. The sleeve part then undergoes, so to speak, an unfavorable tempering. This can lead to unfavorable changes in the structure. In some circumstances, the sleeve part and therefore the tool holder as a whole must be excluded. If the sleeve part is not excluded immediately, there is a risk that cracks will occur in any case if the sleeve part is overheated several times.

[0154] There have already been attempts to improve this by measuring the temperature of the sleeve part using an infrared detector or using a probe that contacts the surface of the sleeve part. However, both types of measurements are prone to errors. Measurements using infrared detectors are highly dependent on the color and condition of the sleeve part. In particular, after a relatively long period of use, the sleeve part may exhibit a certain tempered color, which falsifies the temperature measurement. Dirt or cooling lubricant residues also have an adverse effect.

[0155] Contact type probes also have their own problems, since in this case the accuracy of the temperature measurement depends in particular on the strength of the contact and also on the cleanliness of the surface of the sleeve part in each case.

[0156] Patent document 6 discloses the concept of measuring the current supplied to a coil by a power inverter in order to directly infer the power supplied to the coil at the time of measurement. In this way it is possible to fully exploit the performance of the modules used in the circuit without having to accept the risk of overloading the coil.

[0157] Problem on which the present invention is based The invention is therefore based on the problem of defining a shrink-fit device or a shrink-fit method which makes it possible to limit the thermal load on the sleeve selection, ideally limiting said thermal load to what is necessary.

[0158] The solution according to the invention according to claim 1 According to the invention, a method for monitoring the temperature of a sleeve part of a tool holder inserted in an induction coil of a shrink-fit device is proposed, said method being distinguished by the following features: The current inductance of the induction coil is measured during induction heating and used as a measure of the warming. The supply of current to the induction coil is influenced if the current inductance approaches, reaches or overshoots a defined value. Generally, the supply of current is then stopped.

[0159] Using the current inductance as a measure of the current temperature of the sleeve part has the great advantage that disturbance variables that have heretofore altered the measurement, such as the color, condition and purity of the surface of the sleeve part, are completely eliminated. Measuring the current inductance in relation to electrical variables that have been used heretofore, such as the measurement or calculation of the electrical energy applied up to a certain point in time, has the advantage of being much more accurate. Thus, the shrink chuck is not always heated to a maximum value or for a maximum length of time, but rather power is introduced in a regulated manner, further protecting the shrink chuck and allowing the subsequent cooling process to be accelerated if necessary.

[0160] According to the invention, for one or more tool holders with different sleeve parts, the current inductance reached in the induction coil when the sleeve part inserted in the induction coil is heated to such an extent that it can be shrink-fit or removed is measured and stored.

[0161] Then, at the start of a new shrink-fit operation, a query is made as to which tool holder has been inserted into the induction coil for shrink-fit or removal purposes. In response to this query to the system or to an operator, the user can input this information or it is automatically identified by the system. In this way, for this tool holder, it is possible to read out the inductance present in the sleeve part / induction coil system when the sleeve part has reached the desired temperature for starting the induction heating operation.

[0162] In accordance with the present invention, the heating cycle is terminated when a current inductance is measured that corresponds to the stored inductance present within the sleeve portion of the tool holder when the sleeve portion is ready for shrink fit or removal.

[0163] Further design possibilities It is a further object of the present invention to provide a shrink fit device which is much more compact than currently known shrink fit devices and therefore forms a suitable starting point for designing shrink fit devices for portable use, ideally such that the shrink fit device can be carried like a small suitcase and can be used in a novel way by an operator by quickly taking it to the machine tool where the tool change is to be performed and using it there to perform a tool change on the machine in situ.

[0164] Obviously, this does not exclude that the shrink-fit device can also be used conventionally in a stationary position on a corresponding holding device, but portable use is preferred.

[0165] The problem is solved by a shrink-fit device for clamping and releasing a tool having a tool shank, as described in relation to the main claim.

[0166] The shrink fit device includes a tool receptacle having a sleeve portion open at its free end and constructed from a conductive material for frictionally receiving a tool shank.

[0167] The shrink-fit device further comprises an induction coil surrounding the sleeve portion of the tool receptacle for heating the sleeve portion, said induction coil preferably receiving a high-frequency alternating current (ideally typically at a frequency above 1 kHz) and configured as an annular or cylindrical coil, where the induction coil has at its outer periphery a first shell made of a magnetically conductive and electrically non-conductive material, for example made of ferrite or metal powder material. In the context of the present invention, an electrically non-conductive material does not necessarily have to be an insulator. A material is non-conductive if eddy currents induced by a magnetic field cause little or no heating in the material.

[0168] The shrink-fit device according to the invention further comprises a power semiconductor component for generating an alternating current for powering the induction coil.

[0169] Here, so-called IGBTs are typically used. However, thyristors or MOSFETs can also be used. The shrink-fit device according to the invention also includes an induction coil housing, which is generally made of plastic. Such an induction coil housing usually does not have a magnetic shielding effect or is at least imperceptible. It serves only to protect the components located therein against external influences and at the same time to prevent possible contact between the operator and the voltage-carrying components.

[0170] The shrink-fit device according to the invention is distinguished by the fact that the induction coil and its first shell are surrounded on the periphery by a second shell. The second shell is made of a magnetically non-conductive and electrically conductive material. It is designed in such a way that any stray magnetic field induces a current in it, thus dissipating and thereby dissipating the energy of the stray magnetic field. This means that the second shell completely eliminates the stray electric fields located around it, or at least reduces them, preferably without further measures or instead in combination with further concomitant measures, so that the remnants of the stray electric fields still present in the direct surroundings of the second shell are weak enough not to have a detrimental effect on the power semiconductor components arranged therein.

[0171] This solution according to the invention is further distinguished by the fact that at least the power semiconductor component is accommodated together with the induction coil in an induction coil housing, which preferably consists of an insulating material or is externally coated with such a material.

[0172] It surrounds or houses within itself the following components: an induction coil, its first and second shells and at least power semiconductor components, preferably a capacitor and / or a controller located directly in the power circuit.

[0173] "Surrounding" should be understood at the very least to mean surrounding externally at least along the periphery of the induction coil. Generally, the induction coil housing also extends into the regions of the upper and lower end sides and completely or partially covers them. It therefore has a pot-shaped form. The induction coil housing generally has no wall openings, at least at its periphery, other than local openings required for functional reasons, e.g. for supply lines.

[0174] Further design possibilities The shrink-fit device is preferably designed such that the power semiconductor component is arranged directly on the outer periphery of the second shell. "Directly on the outer periphery" can mean "arranged at a maximum radial distance, for example up to 60 mm, preferably up to 15 mm, from the outer periphery of the second shell of the induction coil." In the absence of a second shell, the outer periphery of the first shell is deterministic.

[0175] However, the power semiconductor component is ideally in direct heat-conducting contact with the second shell by at least one of its surfaces, at most via an adhesive layer. The second shell is preferably designed to form the cooling element of the power semiconductor component. The second shell then absorbs the heat losses occurring in the power semiconductor component and dissipates said heat losses therefrom.

[0176] It has proven to be particularly advantageous if the second shell has one or preferably several cutouts for respectively receiving the power semiconductor component, whereby the preferably semiconductor component is in each case surrounded on at least three or preferably four sides by the second shell. Such a cutout in the second shell forms a region that is particularly well protected against residual magnetic stray fields, since stray field lines cannot penetrate into this deeper recessed cutout in which the power semiconductor component is located. Said stray field lines are instead captured by a surrounding region of the second shell that is higher or located further radially outward.

[0177] It has been found to be particularly advantageous if the shrink-fit device, which comprises at least one rectifier, at least one smoothing capacitor and a resonant circuit capacitor involved in generating a high-frequency alternating voltage for powering an induction coil in the device, has an induction coil and the capacitors are generally grouped around its periphery so as to form a cylindrical ring surrounding the induction coil as it theoretically rotates around the center of the coil. In this case too, the capacitors must be placed directly on the periphery of the second shell of the induction coil.

[0178] In this context, the expression "directly on the periphery" may be understood to mean a maximum radial distance of up to 125 mm, preferably up to 40 mm, measured from the periphery of the second shell of the induction coil. In the absence of a second shell, the outer periphery of the first shell is definite.

[0179] A particularly advantageous embodiment of a shrink-fit device, for which protection is claimed not only dependently but also independently in a manner not dependent on the preceding claims, comprises at least an induction coil for shrink-fitting a tool onto a tool holder and for removing the tool from the tool holder, the induction coil being surrounded by a first shell made of a magnetically conductive and electrically non-conductive material, and the induction coil and its first shell being surrounded by a second shell made of a magnetically non-conductive and electrically conductive material.

[0180] For the second shell, what has already been said above applies. Ideally, also in this case, said second shell is designed in such a way that under the influence of the stray magnetic field of the induction coil passing through it, eddy currents are generated therein, which eddy currents lead to the elimination of the effects of the stray magnetic field at the outer surface of the second shell. Here, the so-called principle of mutual induction can be utilized. Eddy currents are generated in the second shell by the stray magnetic field passing through it, said eddy currents then establish an opposing magnetic field which eliminates the disruptive stray magnetic field, at least to the extent that the power semiconductor components can be accommodated within the vicinity of the second shell without suffering permanent damage.

[0181] Another particularly advantageous embodiment of a shrink-fit device, for which protection is claimed not only dependently but also independently in a manner not dependent on the preceding claims, consists of an induction coil for shrink-fitting a tool onto a tool holder and for removing the tool from the tool holder, which induction coil together with the associated power semiconductor components required to power the induction coil and to generate a transformed AC voltage in relation to the mains voltage is accommodated in an induction coil housing surrounding said induction coil.

[0182] It is preferred that still further components, such as capacitors and / or rectifiers and / or transformers and / or electronic controllers located in the power supply circuit, are also accommodated in the induction coil housing. In this embodiment, no second shell is provided. This can be optionally substituted by the power semiconductor components and / or the set of power electronics and / or the rectifier themselves each having a shielded housing or being accommodated in a shielded compartment. Here, it is preferred that at least the power semiconductor components are actively cooled, for example by the coolant supply of the machine tool.

[0183] This approach is possible with greater effort and is therefore included in the subject matter for which protection is sought.

[0184] In this way, a particularly compact shrink-fit device is obtained, which no longer relies on a separate switchgear cabinet of larger or smaller size standing adjacent to the shrink-fit device and in which these components are housed separately, which goes a long way in achieving the aim of realizing a portable shrink-fit device.

[0185] In all variants of the shrink-fit device according to the invention, that end side of the induction coil facing away from the tool receptacle is preferably designed to be equipped with a cover made of a magnetically conductive and electrically non-conductive material. Said cover is ideally configured as a pole shoe extending over the entire area of ​​the entire end face of the induction coil. This is particularly important to keep the external space free from harmful stray magnetic fields. Exceptionally, even if the cover does not physically cover the entire end face of the induction coil, it still covers it magnetically.

[0186] It has proven to be particularly advantageous if the cover has a shielding collar locally in the center close to the sleeve part, which projects upwards, preferably by at least twice the tool diameter, beyond the free end side of the sleeve part of the tool holder in the direction of the longitudinal axis L. Such a shielding collar prevents the tool shank close to the sleeve part from being exposed to harmful stray magnetic fields or from becoming a source of such magnetic fields which then propagate to the surroundings and have avoidable harmful effects on the power semiconductor components arranged in the direct vicinity of the induction coil.

[0187] It is advantageous if that end side of the induction coil facing towards the tool receptacle is also magnetically conductive and engaged upwardly by an electrically non-conductive material, preferably completely covered by the same except for the receiving opening of the tool holder.

[0188] In a particularly preferred embodiment, the shrink-fit device is arranged to have at least one electric circuit board which is arranged directly on or engages around the outer periphery of the induction coil, preferably in the form of a closed ring around most or all of the outer periphery, and which makes electrical contact with the capacitors and / or power semiconductor components located in the power supply circuit. Circuit board is understood here to mean a panel, preferably having a thickness of at least 0.75 mm, on which conductor tracks made of a metallic material are applied, although a film with metallic conductor tracks can alternatively be used.

[0189] It is particularly advantageous if the circuit board is a circuit board annular disk, the axis of rotational symmetry of which runs preferably coaxially, if not parallel, to the longitudinal axis of the induction coil.

[0190] Ideally, two circuit board annular disks are provided, between which is placed a capacitor located in the power supply circuit along the outer periphery of the induction coil.

[0191] In a particularly preferred exemplary embodiment, the second shell is adapted to form one or more cooling channels, which preferably extend inside said second shell when considered as a whole. For this purpose, the second shell can be formed from two or more parts. The individual parts of the shell are then sealed against each other. This greatly facilitates the manufacture of the cooling channels located inside.

[0192] Another particularly advantageous embodiment of the shrink-fit device, for which protection is claimed not only dependently but also independently in a manner independent of the preceding claims, is a shrink-fit device that is distinguished by the fact that it has a coupling for fixing the shrink-fit device to a receptacle of a spindle of a machine tool. This embodiment also contributes greatly to making a portable shrink-fit device that can be used in practice, since it is dangerous to work with a portable shrink-fit device that is not safely fixed in some way but is merely exposed in some way to the vicinity of a power tool.

[0193] This problem is eliminated by the coupling according to the invention, which makes it possible to fix a shrink-fit device to the machine spindle instead of the shrink chuck after said shrink chuck has been removed in order to carry out a tool change, whereby the shrink-fit device is held reliably for the duration of its operation and can then be quickly separated and removed again.

[0194] In one variant, the coupling can also be used to store the shrink-fit device in a tool magazine of the machine tool, from which it can be automatically inserted into the machine spindle by the tool changer.

[0195] In a further variant, instead of inserting the shrink-fit device into the machine spindle, the shrink-fit device can instead be moved directly to a shrink-fit receptacle clamped to the machine spindle, and the tool changer can take the shrink-fit device from the tool magazine in order to shrink-fit or remove the tool. Also in this respect, a coupling dedicated to the shrink-fit device is particularly advantageous.

[0196] Ideally, if the shrink fit device has an internal cooling mechanism, it is further designed so that coolant can be supplied by the cooling system of the machine tool.

[0197] It is particularly advantageous to design the shrink-fit device in such a way that the induction coil with the first shell, if present the second shell and at least the power semiconductor components and / or the capacitor and / or ideally a set of electronics for actuating the power semiconductor components is accommodated inside a coil housing or a coil housing ring which surrounds at least the outer circumference of the induction coil and preferably engages at least partially over one, preferably both, end sides of the induction coil, resulting in a compact unit which can accommodate all components required for operation conveniently and which is protected against external influences by the common housing and reliably shielded to prevent the operator from touching the voltage-carrying components.

[0198] Ideally, the coil housing is equipped with a plug connector for direct input of single-phase mains AC voltage from the public electricity grid (preferably 110V or 230V), typically a Schuko plug connector (preferably in the form of a plug connector fixed to the end of a flexible supply line).

[0199] This allows the shrink-fit device to be operated almost anywhere. All that is needed is a plug socket like conventional electrical appliances and possibly a conventional extension cable. It is self-evident that the invention is not necessarily limited to this particularly preferred type of electrical supply. The electrical supply may also be three-phase and implemented at different voltages depending on the power required in the particular situation and the electrical supply available at the relevant location. It is self-evident that other voltages are also possible, in particular in countries using different mains voltages in the public electricity grid.

[0200] Instead, it has proven to be particularly expedient to equip the shrink-fit device with a battery for powering it. Such a device can also be highly portable. It is then expedient to provide a chassis, for example in the form of a highly maneuverable trolley, which carries a battery, for example a vehicle starter battery, in a lower region and holds the shrink-fit device, for example in its upper region.

[0201] Furthermore, protection is also claimed for the entire shrink-fit system, which consists of a shrink-fit device of the type according to the invention and which is distinguished by the fact that the shrink-fit system further comprises a different coupling which can be fixed to the shrink-fit device and which can fix the shrink-fit device to the spindle of a machine tool.

[0202] This allows the shrink fit device to be fixed to differently equipped machine tool spindles, so that it is no longer important whether the machine tool spindle for pull-in purposes is equipped, for example, with an HSK coupling or with a steep taper coupling.

[0203] Further design possibilities, functional aspects and advantages are apparent from the following description of exemplary embodiments with reference to the drawings.

[0204] The intermediate shell is preferably arranged between the first and second shell. Said intermediate shell preferably serves as a coolant conducting element to protect the second shell or the semiconductor elements attached thereto against overheating. In contrast to the second shell, said intermediate shell is preferably not divided to ensure a straight coolant guide. The intermediate shell is therefore electrically (but not thermally) insulated at least with respect to the second shell or is made of an electrically non-conductive material from the start. It is self-evident that the coolant guide is sealed with respect to the other components of the shrink-fit device. Alternative concepts for cooling the second shell without a specially formed intermediate ring are also conceivable.

[0205] It may be self-evident that the intermediate shell may also be designed to act as an auxiliary (additional) shield.

[0206] List of Figures FIG. 10 shows the first exemplary embodiment in a longitudinal section through the center. FIG. 11 shows the first exemplary embodiment in a longitudinal cross section through the center, rotated 90° about the longitudinal axis L with respect to FIG. FIG. 12 shows the first exemplary embodiment in an oblique view from above with the shield collar removed. FIG. 13 shows the first exemplary embodiment from above in a front view with the shielding collar attached. FIG. 14 shows the second shell of the first exemplary embodiment equipped with power semiconductor elements. FIG. 15 shows a second exemplary embodiment, which however differs from the first exemplary embodiment only by the nature of its fixation to a machine tool or stand, and is therefore identical to the first embodiment shown here with respect to the placement of the capacitors and the circuit board or printed circuit board. FIG. 16 is a circuit diagram of a circuit for providing power to an induction coil that may be used in accordance with the present invention for an exemplary embodiment. FIG. 17 shows the varying edge sharpness, which is a measure of inductance. FIG. 18 shows a circuit arrangement that may be used in accordance with the present invention to measure inductance and, optionally, also automatically determine the shape of the sleeve portion.

[0207] Exemplary embodiments FIG. 10 shows a first basic overview of the device according to the invention.

[0208] Basic Principles of Induction Shrink Fit and Removal Here, it is possible to clearly see the induction coil 1 with its individual windings 2 in the centre into which the tool holder 4 is inserted in order to shrink-fit the holding shank H of the tool W into or remove it from the sleeve part HP. The functional principle of the shrink-fit and removal is based on that described in detail in patent document 5, the content of which is incorporated into the subject matter of the present application.

[0209] Shielding of induction coils using magnetically conductive, electrically non-conductive means The invention places high demands on the shielding of the induction coil, including shielding of the already known conventional types.

[0210] The induction coil comprises, at its outer periphery, a first shell 3 made of an electrically non-conductive and magnetically conductive material. Usually, the first shell 3 is made of either ferrite or metal powder or metal sinter, the individual particles being separated from one another in an electrically insulating manner, so that, taken as a whole, it is magnetically conductive and electrically non-conductive. It should be noted that, in order to exclude circumvention attempts motivated by the objective of obtaining patent protection, exceptionally, a laminated shell made of layered transformer sheets separated from one another by insulating layers is also conceivable instead. However, in most cases such a laminated shell does not serve the desired purpose.

[0211] The first shell 3 is particularly preferably designed to be completely closed in the circumferential direction, i.e. to completely cover the peripheral surface of the coil, so that, in theory, there is no "magnetic gap" left apart from extraneous local openings such as individual and / or small local bores, etc.

[0212] In exceptional cases, it is also conceivable to design the shell 3 to consist of individual segments that cover the periphery and have a certain free space between them (not shown in the drawings), which allows a rudimentary function to be achieved if, possibly, the radial thickness of the individual segments is selected to be so large in relation to the dimensions of the free spaces that the magnetic fields entering the respective free spaces from the inside are attracted by the segments that are already in the region of the free spaces, so that no significant stray magnetic fields can pass through the free spaces.

[0213] The shield, which is constructed from a magnetically conductive, electrically non-conductive material, preferably does not terminate at the first shell alone.

[0214] Instead, at least one, and preferably both, end sides of the first shell 3 are bordered by magnetic covers 3 a , 3 b made from said material, which covers are generally in contact with the first shell 3 .

[0215] On the end side of the induction coil facing away from the tool holder, the magnetic cover 3a is preferably configured as an annular structure with a central opening forming a passage for a pole shoe, which is preferably fully or preferably partially replaceable, i.e. a shrink-fit or released tool. The term "replaceable" preferably denotes exchangeable without the use of tools, ideally implemented by a connection that can be actuated by hand, for example a bayonet connection. In this way it is possible to process tool holders with different tool shank diameters. It is nevertheless ensured that the end side of the respective sleeve part HP comes into contact with a pole shoe on the inside of the coil.

[0216] On that end side of the induction coil facing towards the tool holder, the magnetic cover 3b is preferably designed as an essentially planar annular disk, ideally fully engaging above the windings of the induction coil and having a central passage for the sleeve part.

[0217] In the present invention, it is highly advantageous, but not essential, if the end magnetic covers 3a, 3b project radially beyond the first shell 3 (at least locally, preferably over at least 75%, ideally completely around) preferably several times, and in most cases at least four times, the radial thickness of the first shell 3. This radial projection should preferably extend at an angle of 75° and ideally 90° to the longitudinal axis L. This provides a reinforced "shielding trough" that extends circumferentially around the coil, the function of which according to the invention will be explained in more detail below.

[0218] Figure 10 shows a particularly preferred embodiment, where the pole shoe consists of a pole annular disk 3aa that stays in place permanently, which is covered on the outside with an insulating material, for example plastic. A shield collar 3ab is replaceably fixed to the pole annular disk 3aa. As can be seen, the pole annular disk 3aa and the shield collar 3ab are preferably magnetically and seamlessly connected to each other. This is achieved by the shield collar being in contact with the pole annular disk, preferably lying on top of it.

[0219] It may be particularly advantageous if the shielding collar has a stop portion AS for abutting against the sleeve portion, as also shown in FIG. 10, which stop portion projects into the interior of the induction coil.

[0220] Likewise, as can be clearly seen from FIG. 10, it is particularly advantageous in many cases if the shielding collar is divided into obliquely movable individual segments having a radial movement component and a movement component in a direction parallel to the longitudinal axis L, so that both the free inner diameter of the shielding collar available as a tool passage and the depth to which the end of the shielding collar facing towards the sleeve part protrudes into the interior of the induction coil are adjustable.

[0221] Ideally, the shield collar has either a conical design or a profile that widens in the coil longitudinal direction towards the tool tip.

[0222] In order to ensure a particularly high quality shielding, which is desirable for the purposes according to the invention, the shield collar projects beyond the free end side of the sleeve part of the tool holder in the direction of the longitudinal axis L by at least twice the size of the tool diameter, preferably by at least 2.75 times.

[0223] Additional shielding using electrically conductive, magnetically non-conductive means Even the thorough shielding provided by the first shell 3 and the magnetic covers 3a, 3b cannot prevent certain stray magnetic fields damaging to semiconductor components from occurring around the induction coil or on the outer surface or in the area of ​​the first shell 3. For this reason, electronic components sensitive to disturbance voltages induced by stray magnetic fields must in fact not be located in this area. This applies in particular to semiconductor components that form the main part of the resonant circuit and operate close to resonance and are used to power the induction coil.

[0224] To further improve the shielding, according to the invention, preferably, at least in the case where cooling of the second shell is omitted, the induction coil and its first shell 3 are surrounded on their outer periphery by a second shell 9, so that the first shell and the second shell are ideally in contact with each other over most or all of their mutually facing outer periphery surfaces.

[0225] Said second shell 9 is made from a magnetically non-conductive and electrically conductive material, "conductive" being understood here to mean not only a so to speak local or "granular" conductivity, but also a material which allows the formation of eddy currents to a degree relevant to the present invention, as will be explained in more detail below.

[0226] A special aspect of the second shell is that it is preferably designed in such a way, and preferably has such a thickness in the radial direction, that under the influence of the stray magnetic field passing through said second shell from the induction coil, eddy currents are generated in it, and this eddy current attenuates the undesired stray magnetic field. Thus, the principle of active shielding by counter magnetic fields is utilized here. In this way, a reduction of the stray electric field at the outer surface of the second shell by more than 50%, ideally at least 75%, can be achieved. In any case, it is important that the stray electric field is reduced at the surface of the second shell to such an extent that it is safe to place semiconductors there.

[0227] It is important that the second shell is radially, i.e. magnetically, separated from the induction coil by the first shell, since otherwise the second shell would heat up excessively, but here this is not the case, since the second shell is only located in the stray magnetic field, and not in the main magnetic field.

[0228] Here, for the term "shell" used in relation to the second shell, the definition given above in relation to the first shell applies analogously. However, the term "shell" in relation to the second shell does not imply that an endless tube section must be used at the periphery. Instead, the shell is preferably divided into individual segments that are electrically insulated from each other, for example by joints filled with glue or plastic. This design serves to prevent a series short circuit, as would occur in the case of an endless tube section, if a dielectric breakdown occurs in the power semiconductor components at the second shell and all power semiconductor components along the second shell are connected to the same potential.

[0229] However, it is important that each individual segment is sized so that the stray magnetic field can induce field-damping eddy currents therein, and in some cases a solid shell is not necessary, but a conductive lattice structure of appropriate thickness (taking into account certain individual conditions) may be sufficient.

[0230] It should be noted here that it is provided merely for mechanical protection purposes, and that a housing with a thin radial wall would be insufficient, even if made of a conductive material. In order to achieve the desired effect according to the invention, a targeted design of the radial wall thickness of the second shell is necessary.

[0231] The preferred material for manufacturing the second shell 9 is aluminium.

[0232] The second shell 9 may have cooling channels in its interior, preferably running in circumferential direction, optionally in the form of a spiral encircling channel, in which case ideally forming a thread.

[0233] In this case it is particularly advantageous for the second shell 9 to be formed from two or more parts, a first part of said second shell having cooling channels formed on its periphery and closed by a second part of said second shell.

[0234] Reference is now made to the left hand portion of figure 11. There it is possible to see the coolant supply line 17 which supplies fresh coolant at the start of one or more cooling channels 16 and drains spent coolant.

[0235] Special arrangement of power semiconductor components, capacitors and optionally an electronic controller As can be clearly seen from figures 11 and 14, the second shell is surrounded on its periphery by a power semiconductor component 10, which will be explained in more detail below, arranged directly on the outer periphery of the second shell.

[0236] In this embodiment, the power semiconductor components have two major main faces and four minor side faces. The major main faces are preferably at least four times larger than each of the individual side faces. The power semiconductor components 10 are arranged such that one of their major main faces is in thermally conductive contact with the second shell 9, generally at its periphery.

[0237] Ideally, the relevant large main surface of the power semiconductor component 10 is adhesively bonded to the outer circumferential surface of the second shell 9 using a thermally conductive adhesive. The second shell 9 thus now performs a dual function: it not only improves the shielding and thus allows the power semiconductor component to be located in its radial vicinity (at a distance of less than 10 cm from the outer circumferential surface), but also optionally simultaneously functions as a cooling element for the power semiconductor component.

[0238] The second shell 9 particularly preferably comprises cut-outs 11, each of which receives a power semiconductor component (see FIG. 14). It can be clearly seen that the cut-outs 11 are ideally designed to completely surround on four sides the power semiconductor components 10 that they receive. In this way, the power semiconductor components 10 fit, as it were, in a recess and are particularly well shielded.

[0239] As can also be clearly seen, each of the power semiconductor components 10 has three connectors 12 for voltage supply, where the connectors 12 of each power semiconductor component 10 protrude into an area forming a setback portion 13 of the second shell 9 (see FIG. 14 ). This optional setback portion 13 can make it easier to wire the connectors 12 of the respective power semiconductor components 10.

[0240] In the described exemplary embodiment, the novel arrangement of the power semiconductor components 10 is, however, not final. Instead, a particularly preferred solution is implemented here, in which the capacitors 14a, 14b are grouped around the outer circumference of the induction coil. The capacitor 14a is preferably a smoothing capacitor, which is a direct component of the power supply circuit, and the capacitor 14b is preferably a resonant circuit capacitor, which is also a direct component of the power supply circuit. The capacitors 14a, 14b theoretically form a cylindrical ring when rotated around the center of the coil.

[0241] This cylindrical ring surrounds the induction coil and preferably also the power semiconductor components grouped around the periphery of said induction coil.

[0242] For the electrical connection of the capacitors 14a, 14b, here a number of electric circuit boards 15a, 15b are provided, each of which engages around the outer circumference of the induction coil. Each of these circuit boards 15a, 15b preferably forms an annular disk. Each circuit board is preferably made of FR4 or a similar material customarily used for circuit boards. As can be seen, the axis of rotational symmetry of each of the two circuit boards, here designed as circuit board annular disks, is in this case coaxial with the longitudinal axis of the coil. Optionally, each of the circuit boards is fixed inside the trough of the magnetic cover 3a, 3b, which projects radially beyond the second shell.

[0243] The upper of the two electric circuit boards 15a has a capacitor, for example a smoothing capacitor 14a or a resonant circuit capacitor 14b, whose connection lugs extend through the circuit board or are connected to the circuit board using SMD technology, so that the smoothing capacitor is suspended from the circuit board. The lower of the two circuit boards is of corresponding construction, with a capacitor, for example a resonant circuit capacitor 14b or a smoothing capacitor 14a, protruding upwards from it. As a whole, when viewed in the direction along the longitudinal axis of the induction coil, the two electric circuit boards 15a, 15b between them receive all the capacitors 14a, 14b of the power supply circuit that supplies the induction coil.

[0244] It can therefore be said that the power semiconductors form a first imaginary cylinder surrounding the induction coil, and the capacitors 14a, 14b form a second imaginary cylinder surrounding the first imaginary cylinder.

[0245] Capacitors, which are almost insensitive to stray magnetic fields, preferably form an imaginary outer cylinder, whereas power semiconductor components, which require installation space with as little stray magnetic fields as possible, form an imaginary inner cylinder.

[0246] Special design of control circuit boards or other circuit boards It may be necessary to shield the circuit board on which the controller is mounted and / or any circuit board that comes into contact with capacitors located directly in the power supply circuitry.

[0247] For this purpose, preferably multi-layer circuit boards, the so-called multi-layer technology, are used. In this case, two or more circuit boards are superimposed on top of each other. The conductor tracks extend mainly or substantially inside the circuit board assembly thus formed. At least the outer main surfaces of the circuit board assembly are metal-plated over substantially the entire area and therefore act as a shield.

[0248] Special supply for induction coils First, as a general observation, it is noted that the coil shown in FIG. 10 is preferably not "fully wound" over its entire length. Instead, it is preferably composed of two winding assemblies that are generally substantially cylindrical. These in each case form one end side of the induction coil. Preferably, one of the two coils (the lower coil in this case) is movable in a direction parallel to the longitudinal axis L and thus adjustable during ongoing operation so that only that area of ​​the relevant sleeve part requiring heating is heated.

[0249] This obviously prevents unnecessary heating and the generation of excessively strong magnetic fields, thereby having a corresponding effect on the stray magnetic fields encountered. Such a coil also contributes to the reduction of reactive power, since it does not have windings in the intermediate region, which are not mandatory in the aspect of achieving the most effective possible heating of the sleeve part of the tool holder, but which, if present, would tend to generate further reactive power without making a substantial significant contribution to the heating operation.

[0250] In order to provide a supply to the induction coil that will give the desired operation and heat the sleeve portion of the tool holder sufficiently quickly, it is generally not sufficient to simply connect the induction coil directly to the 50 Hz mains AC voltage.

[0251] Instead, the frequency of the voltage supplied to the coil must be increased, which is typically done electronically using a frequency converter. However, simply powering the coil with a frequency converter without taking any further special measures, as has been commonly done up until now, results in high reactive power losses.

[0252] From an energy efficiency perspective, these reactive power losses are no longer of relevance; the operating time of the shrink fit device is short, and after only a few seconds of operating time the induction coil heats the sleeve portion of the tool holder sufficiently to allow the tool shank to be attached or removed, so reactive power losses have not been a concern up until now.

[0253] Now, the inventors have realized that it is nevertheless important to avoid reactive power losses, since they lead in particular to heating of the induction coil itself. In order to avoid reactive power losses, it is provided according to the invention that a power supply is provided for supplying the induction coil via a resonant circuit.

[0254] In the resonant circuit according to the invention, most of the required energy oscillates periodically (at high frequency) between the induction coil and the capacitor unit. Therefore, only the energy drawn from the resonant circuit by its heating power and other power losses needs to be replenished every period or every period. In this way, the previously very high reactive power losses are eliminated. This allows the components of the power electronics set to be miniaturized to the extent that they can be integrated into the coil housing for the first time, and also solves the special shielding problems usually associated with this installation.

[0255] With a total weight of less than 10 kg, a portable inductive shrink fit device is thus brought within reach, which the user can transport to a machine tool and use on the spot.

[0256] The set of power electronics which feeds the induction coil is preferably designed as shown in Fig. 16 and is distinguished by the following features: On the input side, the set of power electronics is preferably supplied with the commonly available mains voltage NST, which in Europe is 230V / 50Hz / max. 16A and has corresponding values ​​in other countries, such as 110V in the USA. This is only possible by avoiding previous reactive power levels, whereas previously a 380V three-phase connection was required.

[0257] This does not exclude that a three-phase connection may nevertheless be necessary under certain conditions, for example when the power demand is high. It may be self-evident that three-phase current may also be used when the power demand is low.

[0258] The mains current is then preferably transformed to a higher voltage (transformer T) to reduce the current flowing for a specified power. The current drawn from the grid is transformed by a rectifier G into a direct current, which is then smoothed by one or more smoothing capacitors 14a.

[0259] The resonant circuit SKS itself is supplied with this DC current. The power semiconductor component 10, the resonant circuit capacitor 14b and the induction coil 1 used for shrink-fit and removal form the backbone of the resonant circuit.

[0260] The open-loop and / or closed-loop control of the resonant circuit is performed by a set of control electronics SEK, substantially configured as an IC and supplied with a low DC voltage via a dedicated input GNS, which is optionally picked up downstream of the rectifier G and one or more smoothing capacitors 14a by corresponding voltage dividing resistors.

[0261] The power semiconductor component 10 is preferably implemented by a transistor of the "insulated gate bipolar transistor" type, IGBT for short.

[0262] The set of control electronics SEK preferably switches the IGBTs at a frequency which specifies the operating frequency prevailing in the resonant circuit SKS.

[0263] It is important that the resonant circuit SKS does not operate exactly at resonance, which exists when there is a phase offset of cosφ=1 between the voltage U and the current I. This would then lead to a rapid destruction of the power semiconductor component 10 due to voltage peaks. Instead, the set of control electronics SEK is designed to simply operate the set of power electronics or its resonant circuit SKS in an operating range close to the resonance or natural frequency of the system.

[0264] The resonant circuit is preferably controlled in an open-loop or closed-loop manner such that the following applies: 0.9≦cosφ≦0.99. Values ​​in the range 0.95≦cosφ≦0.98 are particularly advantageous. This again leads to the avoidance of voltage peaks, further facilitating miniaturization.

[0265] It should also be noted that, due to the minimized energy consumption, battery-powered operation is now possible for the first time. In the simplest case, the starter battery of a car can be used as a suitable high-current battery.

[0266] Special Temperature Measurements Shrink-fit devices of that type are preferably optimized in terms of operational safety, which includes at least automatic control of the heating time and / or heating power.

[0267] The so-called inductance u=di / dt is a characteristic variable of a coil through which an alternating current flows. In the case of shrink-fit devices of the type in question, the sleeve part of the tool holder inserted in the peripheral space surrounded by the induction coil forms the main part of the magnetic circuit. In particular, the sleeve part forms the metal core of the coil. The level of inductance measured therefore depends greatly on the extent to which the sleeve part fills the centre or so-called core of the induction coil, i.e. whether the sleeve part in question has a relatively small or large diameter or a larger or smaller mass and therefore a smaller or larger core of the coil.

[0268] Here, the inventors have realized for the first time that the measurable inductance of the induction coil used for shrink fitting depends not only on the geometry of the sleeve part but also, to a practically usable extent, on the temperature of the sleeve part of the tool holder: the hotter the sleeve part, the higher the inductance of the system consisting of the sleeve part and the induction coil.

[0269] This is exploited according to the invention to improve the safety of the shrink-fit device. The implementation or use of the method and the correspondingly designed shrink-fit device exploits the following concept: The number of tool holders that can be used on a shrink-fit device is finite. For this reason, it is not difficult for the manufacturer to measure and parameterize all, or at least the most important tool holders, of the tool holders used in the shrink-fit device.

[0270] Furthermore, it may be easy for the user to measure and additionally store the sleeve parts of the tool holder that are not yet stored in the factory. The device according to the invention optionally has corresponding means or input facilities. Ideally, based on previous parameters and a database, the device identifies the respective contour by measurement and then infers the inductance of the shrink chuck to be used.

[0271] This measurement is carried out in that the sleeve part of the corresponding tool holder is inserted inside the induction coil and the current inductance of the system consisting of the induction coil and the sleeve part inserted therein is then measured in each case when the sleeve part reaches its maximum temperature. In general, the temperature at which shrink fitting and / or removal is optimally possible is taken as the maximum temperature. This prevents the sleeve part from being unnecessarily strongly heated and then cooled again for an unnecessarily long time. It is noted that for purely patent protection reasons or alternatively, the maximum temperature may be somewhat higher than this. The maximum temperature forming the limit value is the maximum temperature that is permissible before destruction occurs, as a so-called safeguard against overheating.

[0272] The maximum values ​​thus measured are generally stored for each tool holder in the shrink-fit device or in its controller, where they are available for comparison at any time.

[0273] For the purpose of shrink-fitting a particular tool holder, a sleeve part is inserted into the induction coil and in this connection it is queried which tool holder is currently to be shrink-fitted or removed. After this information has been entered by the user or after it has been automatically identified, the inductance of the sleeve part / induction coil system when the sleeve part is at the desired temperature is read out for this tool holder. The induction heating operation is then started, whereupon the current inductance is measured in each case. As soon as the currently measured inductance approaches or overshoots a limit value (i.e. the stored inductance), the supply of current to the induction coil is affected and is generally stopped or at least reduced to such an extent that no damage can occur.

[0274] It is preferably ensured that induction heating of the tool holder or its sleeve portion can only commence when it is verified that the tool holder with the cold sleeve portion is indeed inserted into the induction coil.

[0275] To achieve this, further measurements are taken by the manufacturer.

[0276] This measurement is carried out in that the sleeve part of the corresponding tool holder is inserted inside the induction coil and the inductance of the system consisting of the induction coil and the sleeve part inserted therein is then measured in each case when the sleeve part is cold, i.e. at a temperature below 35° for example. The cooling values ​​thus measured are generally stored for each tool holder in the shrink-fit device or in its controller. They are available there for a comparison to be made at the start of the shrink-fit process.

[0277] As soon as the user inputs or it is automatically identified which tool holder with which sleeve part is inserted in the induction coil, the induction coil is energized at least briefly and in the process the current inductance is measured. If now it is found that the current inductance is higher than the stored cooling value, this is an indication that an already hot sleeve part of the tool holder is located inside the induction coil. An error message is then output and / or the heating process is preferably not started or is terminated.

[0278] Preferably, for the purpose of determining the inductance, the edge sharpness of the time / current curve is measured or evaluated and used to determine the inductance. In this regard, reference is made to Figure 17. The left hand half of Figure 17 shows the time / current curve of a system consisting of an induction coil and a sleeve part when powered by a frequency inverter in the presence of a cold sleeve part. The right hand half of Figure 17 shows the time / current curve of a system powered in the same way, but in the presence of a sleeve part heated to the shrink fit temperature.

[0279] A particularly advantageous option in combination with the temperature monitoring according to the invention is the automatic identification of the shape of the sleeve part currently inserted in the induction coil.

[0280] For this, not only the inductance is utilized, but also the level of current drawn by the induction coil over a particular unit of time. Thus, the important measure is not the edge sharpness of the individual waves, but the time / current curve as a whole over a particular time interval.

[0281] To check this, a current (test pulse) of known current magnitude, current type, frequency and duration is applied to the coil by a correctly operating power supply. Current magnitude should be understood here to mean the magnitude of the peak amplitude of the current. Current type should be understood here to mean the nature of the alternating voltage, for example a square wave alternating voltage. Duration should be understood here to mean the period during which the test pulse is applied.

[0282] A different profile of the current consumption within the relevant unit time, i.e. a different time / current curve, arises for the relevant sleeve part depending on the diameter or its mass, which means that each sleeve has a magnetic fingerprint so to speak.

[0283] On this basis, it is again possible for the manufacturer to measure the current consumption within a specific unit of time, i.e. the time / current curve, for all sleeve parts that can be used for processing on the shrink-fit device and store it in the shrink-fit device. When the customer inserts a specific sleeve part of a specific tool holder into the induction coil, a corresponding test pulse is applied to the coil before the start of the actual induction heating operation. The overall time / current curve thus obtained is compared with the stored value in order to determine which sleeve parts have been inserted into the induction coil.

[0284] This eliminates the need for the user to specify what type of tool holder the sleeve part currently wants to machine with the shrink-fit device at the start of the induction heating operation. Rather, this is identified automatically. The shrink-fit device according to the invention can thus automatically obtain its stored inductance value, which is a measure of whether the induction heating operation has to be terminated. At the same time, there is also the possibility for the shrink-fit device according to the invention to automatically obtain also the current inductance cooling value associated with the relevant sleeve part, and to identify whether the sleeve part inserted in the induction coil is actually also cooled before the start of the induction heating operation.

[0285] FIG. 18 shows, from an apparatus point of view, how the measurements described in this chapter can be performed.

[0286] The induction coil 1 can be clearly seen here. The induction coil 1 is supplied by a power supply 100 which generates precisely defined test pulses as described above. In order to generate such test pulses with the required precision a closed loop control unit 110 can be provided.

[0287] Between the two connecting wires of the induction coil 1 there is a measuring device 101 for measuring the current inductance, which can be a measuring device of a type known per se. Said measuring device 101 preferably comprises a comparator for comparing the currently measured inductance with a limit value of inductance, which limit value is a measure for the sleeve part being sufficiently heated to allow shrink-fit or removal. The comparator can also preferably compare whether the currently measured cooling value of the current inductance corresponds to the cooling value of the inductance that the sleeve part currently introduced in the induction coil should have.

[0288] An auxiliary circuit 103 is connected via the transducer 102. Said auxiliary circuit serves to determine the shape of the sleeve part currently inserted in the induction coil. For this purpose, the auxiliary circuit comprises at least one measuring capacitor 104 and at least one measuring device 105. The measuring device 105 is able to measure the current voltage across the capacitor. Furthermore, the auxiliary circuit generally comprises a discharge resistor 106, which is usually connected to ground and ensures that the measuring capacitor is discharged again after the test cycle, although the resistance value is chosen high enough so as not to adversely affect the relatively short test cycle itself.

[0289] The time / current curve exhibited by the induction coil to which the test pulse is applied varies depending on the design of the sleeve part HP inserted inside the induction coil 1 (see also the two variants in FIG. 18), which causes the time / current curve measured on the capacitor 104 by the measuring device 105 to vary accordingly. This time / current curve is a fingerprint related to the properties of the sleeve part in each case.

[0290] Portable Unit A special aspect of the invention is that for the first time a portable shrink-fit unit is made possible, which typically weighs less than 10 kg in the operating state and is therefore easily transported or maneuvered, also due to its design of only the coil housing with the plug connector. It is therefore moved to the machine tool to be used there in situ. In this way it is possible to depart from the previous concept of static shrink-fit machines, where the tool holder must be brought in and then taken out again in order to carry out and continue a tool change.

[0291] First, typically at least the following components are housed within a common housing: the induction coil, the first shell, the second shell (if present), the power semiconductor elements, and preferably the capacitor. Ideally, in addition to the induction coil, all components required to operate the induction coil, including a set of control electronics, are housed within the common housing.

[0292] Preferably, only the power supply cable leaves the housing, which serves as the voltage supply for the shrink-fit device thus formed and for this purpose ideally has at its end a plug connector which allows connection to the voltage supply without the use of tools, whereby preferably the mains voltage is used as the voltage supply as described above, the end of the power supply cable is then preferably equipped with a Schuko plug corresponding to the relevant national requirements.

[0293] When the shrink-fit device is held by hand, it is advantageous to attach centering means to the coil housing, which makes it easier to center the coil with respect to the tool axis. The centering means can be designed, for example, as radially movable fingers Fi, as shown in figures 10 and 11.

[0294] It has proven to be particularly advantageous if the device is equipped with at least one coupling KU, which allows it to be coupled to a machine tool.

[0295] In this way, the device can be simply fixed to the machine tool and then placed in a safe working position protected against contamination by coolant and chip particles.

[0296] This coupling KU preferably corresponds to a typical coupling profile, for example an HSK profile, as is shown in FIG. 11, as used for tool holders to be processed using the shrink-fit device according to the invention. To bring the shrink-fit device according to the invention into a safe working position, it is only necessary to disconnect the tool holder to be subjected to a tool change from the spindle of the machine tool and to couple the shrink-fit device with its identical coupling profile to the spindle of the machine tool in place of said tool holder. It is particularly advantageous if the coupling of the shrink-fit device can be operatively removed from the shrink-fit device, preferably by hand without the use of tools (in particular by using a bayonet fastener). In this way, the coupling of the shrink-fit device can be easily adapted to the coupling type (steep taper coupling, HSK, etc.) used on the relevant machine tool.

[0297] Ideally, each coupling is connected to the shrink-fit device according to the invention in such a way that the coolant / cooling lubricant discharged from the cooling system of the machine tool can flow through at least one cooling channel that the shrink-fit device has, preferably within its second shell, as described above.

[0298] Here, a cooling device may be provided, preferably integrated in the shrink-fit device (usually adjacent to the induction coil), into which the sleeve part of the tool holder is inserted for active cooling to a temperature safe for touching after completion of the shrink-fit operation.

[0299] The cooling device is advantageously supplied by the cooling system of the machine tool, generally also via the coupling, so that protection is also claimed for the use of cooling liquid discharged by the machine tool for cooling purposes in the shrink-fit device (cooling the second shell and / or the tool holder).

[0300] Alternatively, the shrink-fit device can also be stored in a tool magazine of the machine tool. The tool changer can then automatically insert the shrink-fit device into the machine spindle or move it to a tool receptacle that is clamped to the spindle for tool removal or shrink-fit purposes. In the latter case, energy can be supplied via a cable connected by a plug connector directly to the shrink-fit device. In either case, there is no need to hold the shrink-fit device by hand.

[0301] General Observations Protection is also claimed for a shrink-fit device, or method, or use having only one or more of the features of the following paragraphs, respectively, apart from the features claimed by the currently established set of claims. Protection is also claimed for a shrink-fit device, or method, or use having the features of one or more of the paragraphs listed below and further having other features from the remainder of this specification, including the currently established claims or drawings.

[0302] A shrink-fit device which is distinguished by the fact that the circuit board is an annular circuit board disk, the axis of rotational symmetry of which runs preferably coaxially, if not parallel, to the longitudinal axis of the induction coil.

[0303] A shrink-fit device, which is distinguished by the fact that two circuit board annular disks are provided, between which a smoothing capacitor is placed along the periphery of the induction coil.

[0304] A shrink-fit device which is distinguished by the fact that the second shell preferably defines one or more cooling channels extending inside said second shell.

[0305] A shrink-fit device which is distinguished by the fact that the device has a coupling for fixing the device in a receptacle of the machine tool spindle.

[0306] A shrink-fit device which is distinguished by the fact that it is designed in such a way that it can be supplied with coolant from the cooling system of the machine tool.

[0307] A shrink-fit device that is distinguished by the fact that an induction coil having first and second shells, at least a power semiconductor component and / or a smoothing capacitor, and ideally a set of electronics for operating the power semiconductor component, are housed inside a coil housing or coil housing ring that surrounds at least the periphery of the induction coil and preferably also covers and engages at least one, preferably both, end sides of the induction coil.

[0308] A shrink-fit device which is distinguished by the fact that the coil housing has a plug connector for direct input of the mains AC voltage from the public power grid (110V, 230V or 380V).

[0309] Shrink-fit devices are distinguished by the fact that they are battery operated.

[0310] A shrink-fit device which is distinguished by the fact that the shield collar is provided consisting of individual segments so that it can be moved both with a radial component of movement and with an axial component of movement.

[0311] A shrink-fit device which is distinguished by the fact that a centering element is provided on the end side of the induction coil facing towards the tool holder and / or in the air interior space of the induction coil, which, when the sleeve part is pressed into the induction coil until it stops, presses said sleeve part in any case so as to position said sleeve part coaxially within the induction coil.

[0312] A shrink-fit device that is distinguished by the fact that it has at least two coil winding portions that can move toward or away from each other in a direction parallel to the longitudinal axis during operation for the purpose of adjusting to the shape of the heated sleeve portion.

[0313] A shrink-fit system consisting of a shrink-fit device according to any one of the preceding paragraphs, distinguished by the fact that it further comprises a different coupling, fixable to the shrink-fit device and capable of fixing the shrink-fit device to a spindle of a machine tool.

[0314] Although the present invention has been illustrated and described in more detail on the basis of preferred exemplary embodiments, the invention is not limited to the disclosed examples, and other variations can be derived therefrom without departing from the scope of protection of the invention. [Explanation of symbols]

[0315] List of reference symbols 2. Heat treatment equipment, shrink-fit equipment, cooling equipment, shrink-fit equipment with cooling equipment 4 Shrink chuck 6 Shank / rotating tool, milling cutter / milling tool 8 Receiving means, receiving opening 10 Center axis, coil axis 12 Heat treatment equipment, induction coil mechanism, cooling equipment / unit 14 Measurement / Calculation Units 16, 16' Temperature sensor, pyrometer with radiation detector, radiation detector 18 (coil) housing 20 Recess 22 measurement channels 24 Coil Winding 26 Aperture 28 Control Unit 30 ratio pyrometer 32 Sleeve section 34 Clamping Area 36 End opening 38 Front end 40 Tool shank, milling cutter shank 42 Pre-work part 44 Axial center area 46 Coil side inner part 48 Exterior Wall 50 Induction coil housing 52 Cable 54 Focusing devices, shielding means, diaphragms 56 (Annular) structural units, measuring / sensing 58 (Annular) structural unit / central axis of measuring ring 60 Sensors 62 (Infrared) Reflection Sensor 64 Indication means, (LED) (thermal) status display 70 Columns 72 Cooling Head 74 Cooling attachment 76 (Measuring ring) Housing 78 Transmitter 80 Receiver 82 (red) light emitting diode 84 Supply Line 86 Microcontrollers 88 (Left) Arm 90 (Right) Arm 92 Passages, recesses 94 (green) light emitting diode 100 ways 120 Heat treatment, heating, shrink fit / removal, cooling 140 Checking the resulting shell / surface temperature 160 Control of heat treatment, control of heating / cooling, control of supply of heating power or current 200 Interaction of multiple sensors (16, 62) 220 Identification of a shrink chuck (4) received in a receiving means (8) using a reflective sensor

Claims

1. An apparatus (2), particularly a shrink-fit apparatus (2), or a cooling apparatus (2), or a shrink-fit apparatus (2) with a cooling apparatus (2), for heat-treating, particularly induction heating or cooling, a shrink-fit apparatus (2) having receiving means (8), particularly receiving opening (8) for receiving the shrink-chuck (4), and a heat treatment unit (12), particularly induction coil mechanism (12), or cooling unit (12) concentrically surrounding the receiving means (8), particularly with respect to a central axis (10), and particularly a measuring / calculating unit (14) for non-contact temperature measurement of the shrink-chuck (4), in the apparatus (2), The measurement / calculation unit (14) includes at least one temperature sensor (16) for non-contact detection of the shell temperature of the shrink chuck (4) which is located in the receiving means (8), and a reflectance sensor (62), in particular an infrared reflectance sensor (62), which is located around the receiving means (8). The measurement / calculation unit (14) is A current (test pulse) of known magnitude, form, frequency, and effective period is applied to the heat treatment unit (12), particularly the induction coil mechanism (12), before the start of the actual heat treatment operation, particularly the cooling operation or induction heating operation, on the shrink chuck (4) inserted within the heat treatment unit (12), particularly the induction coil mechanism (12). For the test pulse, the time / current curve of the shrink chuck (4) inserted in the heat treatment unit (12), particularly the induction coil mechanism (12), is confirmed, and the overall time / current curve confirmed for the test pulse is adopted as the magnetic fingerprint of the shrink chuck (4) inserted in the heat treatment unit (12), particularly the induction coil mechanism (12). Using the magnetic fingerprint, the geometric information items of the heat treatment unit (12), particularly the shrink chuck (4) inserted into the induction coil mechanism (12), especially the outer diameter, are confirmed. Reflectance measurements are performed by the reflection sensor (62) on the shrink chuck (4) inserted into the heat treatment unit (12), particularly the induction coil mechanism (12), and in particular, the geometric information item (correction value 1) is used to perform and correct the reflection measurements by the reflection sensor (62) on the shrink chuck (4) inserted into the heat treatment unit (12), particularly the induction coil mechanism (12), and The apparatus (2) is configured such that the temperature of the shrink chuck (4) inserted into the heat treatment unit (12), particularly the induction coil mechanism (12), is measured and corrected by the temperature sensor (16) using the reflectance measurement and the geometric information items, or using the corrected reflectance measurement (correction value 2).

2. The apparatus (2) according to claim 1, wherein the measuring unit (14) has a plurality of temperature sensors (16) arranged around the receiving means (8), and in particular a plurality of temperature sensors (16) for non-contact detection of the shell temperature of the shrink chuck (4) arranged within the receiving means (8), or the measuring unit (14) has at least one temperature sensor (16') arranged around the receiving means (8) and inclined in particular with respect to the central axis (10), and in particular at least one temperature sensor (16') for non-contact detection of the shell temperature of the shrink chuck (4) arranged within the receiving means (8).

3. The apparatus (2) according to claim 1 or 2, characterized in that at least two, in particular some or all, of the temperature sensors (16) have different configurations / measurement settings.

4. The apparatus (2) according to claim 1 or 2, characterized in that each of the temperature sensor (16) or the plurality of temperature sensors (16) and / or the gradient temperature sensor (16') is configured as a radiation detector, in particular as a pyrometer with a radiation detector, for detecting thermal radiation from a shrink chuck (4) disposed within the receiving means (8).

5. The apparatus (2) according to claim 1 or 2, characterized in that the tilt angle of the tilt temperature sensor (16') is 30° to 60°, and particularly 45°.

6. The apparatus (2) according to claim 1 or 2, characterized in that the sensors (16, 60, 62) are arranged in a circular manner with respect to the central axis (10) and / or at different axial heights on or around the receiving means (8).

7. The apparatus (2) according to claim 1 or 2, characterized in that the heat treatment unit (12) and / or the housing (18, 50) of the heat treatment unit (12) has at least one recess (20), and a sensor (16, 60, 62) or, in each case, one of the sensors (16, 60, 62) is arranged in or within the recess (20).

8. The apparatus (2) according to claim 7, characterized in that the recess (20) is configured as a measuring channel (22) that extends substantially radially with respect to the central axis (10) through the heat treatment unit (12) and / or through the housing (18, 50) of the heat treatment unit (12).

9. The apparatus (2) according to claim 8, wherein the one heat treatment unit (12) configured as an induction coil mechanism (12) has a coil winding (24) wound to leave one or more of the measurement channels (22) free, and / or a partial induction coil mechanism having a partial induction coil mechanism in which one or more of the measurement channels (22) are formed therein.

10. Apparatus (2) according to claim 8, characterized in that at least one of the sensors (16, 60, 62) is at least partially located in or on the measurement channel (22), in particular so that the at least one sensor (16, 60, 62) performs a measurement through the one such measurement channel (22), in particular so that each of some or all of the sensors (16, 60, 62) is at least partially located in or on the measurement channel (22), in particular so that the sensors (16, 60, 62) perform a measurement through the measurement channel (22).

11. The apparatus (2) according to claim 1 or 2, characterized in that the sensors (16, 60, 62) are arranged within a substantially annular structural unit (56), particularly in a circular manner around the central axis (58) of the substantially annular structural unit (56), and / or at different axial heights or particularly the same axial height with respect to the central axis (58) of the substantially annular structural unit (56).

12. The apparatus (2) according to claim 11, characterized in that the substantially annular structural unit (56) is arranged coaxially with respect to the central axis (10) within the apparatus (2), and particularly adjacent in the axial direction with respect to the heat treatment unit (12), particularly the induction coil mechanism (12), or the cooling unit (12).

13. The apparatus (2) according to claim 11, characterized in that sensors of the same type (16, 60, 62) are arranged adjacent to each other within the substantially annular structural unit (56).

14. The apparatus (2) according to claim 1 or 2, characterized in that the measurement / calculation unit is configured such that the resulting shell temperature of the shrink chuck (4) placed in the receiving means (8) can be confirmed using the corrected temperature measurement from the temperature sensor (16).

15. The apparatus (2) according to claim 14, characterized in that a controller (28) of the heat treatment unit (12), in particular the induction coil mechanism (12) or the cooling unit (12), is configured such that the supply of power to the heat treatment unit (12), in particular current to the heat treatment unit (12) configured as an induction coil mechanism (12), is controllable (160) based on the resulting shell temperature.

16. The apparatus (2) according to claim 1 or 2, characterized in particular by a tool receptacle (4) disposed within the receiving means (8), and in particular by a display means (64) for displaying the thermal state of the shrink chuck (4).

17. A method (100) for operating the apparatus (2) according to claim 1 or 2 of the apparatus, in particular a method (100) for inductively heating (120) or cooling the shrink chuck (4) in the apparatus (2) according to any one of claims 1 to 16 of the shrink fit apparatus, A current (test pulse) of known magnitude, form, frequency, and effective period is applied to the heat treatment unit (12), particularly the induction coil mechanism (12), before the start of the actual heat treatment operation, particularly the cooling operation or induction heating operation, on the shrink chuck (4) inserted within the heat treatment unit (12), particularly the induction coil mechanism (12). For the test pulse, the time / current curve of the shrink chuck (4) inserted within the heat treatment unit (12), particularly the induction coil mechanism (12), is confirmed, and the overall time / current curve confirmed for the test pulse is adopted as the magnetic fingerprint of the shrink chuck (4) inserted within the heat treatment unit (12), particularly the induction coil mechanism (12). Using the magnetic fingerprint, the geometric information items of the heat treatment unit (12), particularly the shrink chuck (4) inserted into the induction coil mechanism (12), especially the outer diameter, are confirmed. Reflectance measurements are performed by the reflection sensor (62) on the shrink chuck (4) inserted into the heat treatment unit (12), particularly the induction coil mechanism (12), and in particular, the geometric information item (correction value 1) is used to perform and correct the reflection measurements by the reflection sensor (62) on the shrink chuck (4) inserted into the heat treatment unit (12), particularly the induction coil mechanism (12), and A method (100) in which a temperature measurement performed by the temperature sensor (16) on the heat treatment unit (12), particularly the shrink chuck (4) inserted into the induction coil mechanism (12), is corrected using the corrected reflection measurement (correction value 2).

18. The method according to claim 17 (100), characterized in that the resulting shell temperature of the shrink chuck (4) placed within the receiving means (8) can be confirmed using the corrected temperature measurement from the temperature sensor (16).

19. The shrink chuck (4) is induction heated (120) and thus expanded within the receiving means (8) surrounded by a heat treatment means (12) configured as an induction coil mechanism (12), and the heating operation is controlled (160) using the resulting shell temperature, and in particular, the heating operation is automatically stopped when a specified temperature is reached, or The method (100) of claim 17, characterized in that the shrink chuck (4) is cooled (120) within the receiving means (8) surrounded by a heat treatment device (12) configured as a cooling unit (12), and the cooling operation is controlled (160) using the resulting shell temperature.

20. The method according to claim 17, characterized in that different calibrations / settings, in particular different emissivity ε, are set for a plurality of temperature sensors (16), and measurements made using the plurality of temperature sensors (16) are compared and / or processed together, and the resulting shell temperature is determined (140) from the measurements.

21. The method according to claim 17, characterized in that signals from one identical radiation sensor (62) are evaluated in different ways.

Images