EP2756733A1

EP2756733A1 - Induction coil unit

Info

Publication number: EP2756733A1
Application number: EP12762249.6A
Authority: EP
Inventors: Franz Haimer
Original assignee: Franz Haimer Maschinenbau KG
Current assignee: Franz Haimer Maschinenbau KG
Priority date: 2011-09-13
Filing date: 2012-09-11
Publication date: 2014-07-23
Also published as: WO2013037761A1; US20150041456A1; JP2014532257A; CN103828484A; DE102011082611A1; JP6170050B2; US9832819B2

Abstract

The induction coil unit for heating up a component which is rotationally symmetrical with respect to an axis (7), especially a tool holder (5), comprises a plurality of coils (19) arranged about the axis (7) of the tool holder (5), said coils having pole elements that are interconnected by a common yoke ring (17) and that are radially mobile with respect to the axis (7). Upon excitation by alternating current, the coils (19) produce a magnetic flux running in the tool holder (5) in the peripheral direction for inductively heating the tool holder (5). The induction coil unit (1) can be oscillated in the direction of the axis (7) by means of a drive (87), the pole elements (21) oscillating along the tool holder (5). The induction coil unit according to the invention is able to heat a comparatively large portion of the tool holder (5) despite comparatively little energy consumption and despite a comparatively compact design.

Description

Induction coil unit Description

The invention relates to an induction coil unit for heating a rotationally symmetrical component of an electrically conductive material relative to an axis, and in particular for heating a sleeve part which holds an elongated object in a press fit in a centering receiving opening, preferably for heating the sleeve part of a tool holder which is in its central axis of rotation to the receiving opening a shaft of a rotary tool, in particular a drilling or milling tool, holds in a press fit.

It is known, the cylindrical shaft of a rotating tool to be driven, for example a drill or milling cutter, in a in the

Shrink substantially cylindrical receiving opening of a tool holder. The tool shank has related to the

Inner diameter of the receiving opening excess. For inserting or removing the tool shank, the sleeve part of the tool holder containing the receiving opening is heated until the inner diameter of the receiving opening is stretched so far that the tool shank can be inserted or removed. After cooling, the sleeve part holds the tool shank in a press fit.

While the insertion of the tool shank into the heat-extended tool holder usually proceeds without any problems, the removal of the tool shank from the tool holder of the

Tool holders are heated so quickly that the tool holder stretches before by heat conduction of the tool shaft is heated with, resulting in jamming of the tool shaft in the tool holder and makes the clamping of the tool difficult, if not impossible. It is known, the usually made of steel, ie an electrically conductive material tool holder inductively by means of a

Induction coil unit to heat generated eddy currents. The

Induction coil of conventional devices encloses this coaxially the tool holder. Such an induction coil generates in the tool holder enclosed by it an axially extending magnetic flux which heats the tool holder.

However, it has been found that such an induction coil generates stray magnetic fields which not only heat the tool holder but also, to a certain extent, the tool held therein in a press fit. To avoid this, it is known from DE 199 15 412 A1, the tool adjacent to the end face of the induction coil with a

Polscheibe made of soft magnetic material, such as ferrite, cover. The resting on the tool-side end of the tool holder pole disk concentrates the magnetic flux in the tool holder and shields to some extent the tool shank against stray fields. However, the induction coil known from DE 199 15 412 A1 can not heat the tool holder uniformly, so that it is locally too

Overheating damage may occur to the tool holder. In addition, the resting on the forehead of the tool holder prevents

Polscheibe, that radially projecting tools can be shrunk until brought directly to the front of the tool holder.

From DE 10 2005 005 892 A1, a further induction coil unit is known in which a plurality of circumferentially distributed pole elements of soft magnetic material are arranged radially adjustable in a yoke ring of soft magnetic material. The

Pole elements have the tool holder radially facing end surfaces, which in a linear abutting contact with the peripheral surface of the

Tool holder can be brought. The pole elements are enclosed by separately assigned coils and induce when they are in themselves be fed with alternating current known in the tool holder, the magnetic flux flows through the tool holder in the circumferential direction and generate the tool holder heating eddy currents. Because the

Pole elements rest on the peripheral surface of the tool holder, there is no need for a fitting on the end face of the tool holder Polscheibe, as provided in DE 199 15 412 A1, and accordingly radially projecting tools can be shrunk to the front of the tool holder zoom.

In the case of the induction coil unit known from DE 10 2005 005 892 A1, the axial ends of the end faces of the pole elements resting against the outer surface of the tool holder extend at a distance from the latter

Tool holder, which increases the magnetic resistance of the magnetic flux circuit in the region of the ends, whereby a local overheating of the

Tool holder is sufficiently avoided in these areas for some applications. However, it has been shown that the

Adaptation of the end faces of the pole elements is expensive and for some applications to avoid local overheating of the

Tool holder is insufficient.

Conventional induction coil units direct the magnetic flux generated by induction coils in the component to be heated so that the

Magnet flux completely overlaps the area to be heated. In general, in this case, a region is heated inductively, which is greater than, for example, in a tool holder by the clamping and unclamping of the tool to be stretched, axial region. conventional

Induction coil unit are therefore energized as well as spatially oversized, in particular to components, in particular

To heat tool holders of different dimensions. However, the oversizing of conventional induction coil units can lead to stray magnetic fields, which can heat the tool auszuspannende and the clamping can make it difficult to considerable extent. In a first aspect, it is an object of the invention to show a way how the component and in particular a tool holder with

comparatively low energy consumption and thereby reduced field strength of stray magnetic fields can be safely heated.

Under the first aspect, the invention of a

Induction coil unit for heating a relative to an axis rotationally symmetrical component, in particular a tool holder, from, which comprises: a central axis for the receiving space for the component, at least one pole element made of a material with

soft magnetic, magnetic flux conducting properties, at least one can be fed with AC coil for generating magnetic flux in the at least one pole element, wherein the at least one pole element has an axis substantially radially facing end surface in abutting contact or close contact with the outer peripheral surface of the component stands.

In such an induction coil unit according to the invention

provided that a drive arrangement is provided which at least the at least one pole element and a holder for the component at least during a portion of the period in which the at least one coil is supplied with alternating current, relative to each other moving longitudinally movable and / or in the direction of the axis the axis drives in rotation. The induction coil unit and the holder may in this case be connected to one another with a device unit.

Such an induction coil unit is based on the idea that the magnetic flux generated by the at least one coil does not extend as a whole continuously supplying heating of the component, but to limit to a portion of the entire area to be heated and instead to move this portion in the manner of a scanning once or even repeatedly over the entire area to be heated. In this case, use is made of the fact that the component is able to store the heat generated locally in the partial areas, but that less energy must be applied to generate the eddy currents in the partial area. In addition, the total area to be heated can be determined solely on the basis of a suitable choice of the scanning movement. By choosing the speed and / or the residence time can be

Amount of heat vary, which is supplied to the component locally. This can be achieved, in particular, in that the at least one coil and the at least one pole element form a unit movable relative to the holder, and the drive arrangement forms this unit and the holder in

Direction of the axis relative to each other in an oscillating motion drives. By controlling the amplitude of the oscillating motion and / or the frequency, the desired overall heating of the component can be controlled. Appropriately, in this case the drive assembly is associated with a controller, which also the instantaneous speed of

Relative movement and / or the current strength of the at least one coil feeding alternating current depending on the instantaneous position of the at least one pole element relative to the holder controls.

The induction coil unit may comprise a plurality, in particular an even number, of pole elements distributed around the axis, which are movably guided radially to the axis on the unit and are movable between a position near the axis and a position remote from the axis and with their axis substantially radial facing end surfaces in the position near the axis in abutting contact or almost abutting contact with the outer peripheral surface of the component. Such

The induction coil unit can be moved in an oscillating manner along the component in the direction of the axis in order to move it axially from the pole elements

to enlarge the covered area. In other words, the axial height of the pole elements may be smaller than the axial region of the component to be heated. The pole elements are here

expediently at least in a partial region of its axial height in abutting contact or almost abutting contact with the component.

In conventional induction coil units, as are known for example from DE 199 15 412 A1, the magnetic flux is generated by a single coil enclosing the component, wherein the coil extends over an axial length which is greater than the axial region of the component to be heated, here the tool holder. The first aspect of the invention can also be applied to induction coil units of the type known from DE 199 15 412 A1, in which a coil enclosing the component is provided, on at least one axially located side of the coil, preferably on both axial sides of the coil or more

Pole elements are provided. The pole elements can also be designed as a pole disk, as far as the opening diameter of the pole disk allows said oscillation movement of the coil relative to the component in the direction of the axis. Instead of the pole disk can also be several in

Circumferentially provided against each other angularly offset pole elements, which are optionally radially movable to the axis, so as to one

For example, to follow conical outer shell of the component fitting.

The first aspect of the invention can be particularly in a

Use induction coil unit of the type known from DE 10 2005 005 892 A1, since such an induction coil unit has comparatively small axial dimensions. An induction coil unit of this type comprises: a centering space for the component, in particular an even number distributed around the axis around, in particular distributed at equal angular intervals Pol elements a material with soft magnetic, magnetic flux conducting

Characteristics, at least one can be fed with alternating current coil for generating magnetic fluxes in the pole elements, in particular a plurality of these coils, wherein the pole elements are guided radially to the axis movable on the unit and between a near axis of the first position and a second axis of the second position are movable and wherein the pole elements of the axle have substantially radially facing end surfaces which are in abutting contact or nearly in abutting contact with the outer peripheral surface of the component in the first position.

Conveniently, the end faces of the pole elements in this case at least in a partial region of its axial height along a generatrix of an outer peripheral surface of the component in abutting contact or almost in abutting contact with the outer peripheral surface of the component.

The generatrix of the outer peripheral surface is the contour boundary line in the mathematical sense. If here and in

The following is the radial direction, axial direction or circumferential direction, the directional information always refer to said axis. Pole elements as well as materials mentioned here and below with soft-magnetic, magnetic flux-conducting properties, such as pole rods or yokes or the like, are made of electrically nonconductive material in order to avoid eddy current losses in these elements. The number of pole elements and / or coils is preferably even. It is understood that an odd number of pole elements and / or coils can be used. Also, a "transverse field" of the kind explained also with one of the number of pole elements deviating number of coils are generated. In individual cases, a single coil is sufficient.

The pole elements may be one-piece plates or rods of rectangular, square or round cross-section and, accordingly, the shape of the end surface varies along the one-piece element. It is understood that the area of the end face can also be an operationally removable part of the otherwise one-piece pole element, as explained in DE 10 2005 005 892 A1.

So that the pole element can also adapt to a contour of the component which changes in the direction of the axis, it can also be designed as a stack of a plurality of pole rods which are guided parallel to one another and are movable radially relative to one another. The axis-facing ends of these pole bars form Teilendflächen, which together form the end face of the

Form pole elements.

The inclination of the end face of the pole elements intended for bearing against the component should be selected so that the end face is in the closest possible contact, in particular line contact, with the outer jacket of the component. In many cases, the component, as is customary, for example, with tool holders, has a cone-shaped outer jacket, which can vary from tool holder to tool holder. In DE 10 2005 005 892 A1 pole elements are described whose end surface forming region is formed by a hinged component hinged so as to be able to adapt to a changing angle of inclination of the contour. However, since the hinged component is part of the magnetic flux-conducting pole, the magnetic resistance increasing air gaps can not be excluded. In addition, the pole elements made of brittle material, usually ferrite, which carries the risk of damage in itself. In a second aspect, which relates to a preferred embodiment of the above-explained first aspect, but also has independent inventive significance in induction coil units with different characteristics from the first aspect, it is provided that the pole elements in each case a guide element between the first and the second position movable are guided and that the guide elements are each mounted to pivot about a transverse to the axis and in particular in a common plane normal to the axis. Since differently described in DE 10 2005 005 892 A1, the pole elements are pivoted as a whole in order to adapt the end surfaces of the angle of inclination of the outer shell of the component, the pole elements are mechanically stable despite their adaptability and have compared to conventional pole elements a comparatively low magnetic resistance. It is understood that the guide elements for a same direction pivoting movement can be coupled via a transmission with each other and in particular with a common drive member to bring them together in, for example, linear contact with the outer shell of the component. In this way, the adaptation period can be kept short if, for example, different tool holders are to be heated.

The idea claimed under the second aspect can be used not only with one-piece pole elements, but also with advantage

Pole elements which are formed as a stack of a plurality of mutually parallel radially to the axis relative to each other movably guided pole rods to the contact surface of the component not only approximated in stages in

To be able to bring investment contact with the pole rods, but to be able to create the pole rods in turn linear or flat to the component.

Each pole element may have a linear toothing, which meshes with a drive pinion mounted on its guide element, wherein the

Drive pinion are in drive connection with a common drive member, as hereinafter also for from stacking pole rods

constructed pole elements will be described. The drive mechanism provides for a positive or non-positive feed and return movement of the pole elements. The feed movement, which brings the pole element into abutting contact with the component, ensures at an angle error between the end face of the pole member and the component that a tilting moment is exerted on the guide member which brings the pole member in line or surface contact with the device. A separate drive member for the

Guide element, as will be explained below, may therefore be omitted. Also ensure that occurring during the energizing of the coils

Magnetic forces for a further alignment of the angular position of the pole element relative to the component. This applies in particular to the previously explained second aspect of the invention.

In the case of the oscillation movement taking place in the direction of the axis, a relative movement between the end face of the pole elements on the one hand and the outer peripheral face of the component to be heated on the other hand can also occur. In order to avoid wear damage to the pole elements on the one hand and the components to be heated on the other hand is provided in a preferred embodiment that the at least one pole element of the axis adjacent to a transverse axis to the axis of rotation rotatable or pivotable end surface of a material with soft magnetic, magnetic flux conducting properties carries, which forms a curved around the axis of rotation, in particular coaxially to the axis of rotation circularly curved, on the outer peripheral surface of the component abrollable in abutting contact end face. The

End surface element may be formed as a wheel or roller or ball and rolls off to reduce wear on the component. In this

Embodiment, the end surface element is part of the magnetic flux path. As far as each pole element carries only a single rotatable or pivotable end surface element, it is sufficient if the pole element is guided only radially to the axis movable. The pole element does not have to be additionally pivotally mounted, since angular errors are compensated by the end face element. An end surface element of the type described above is in point contact on a conical outer peripheral surface of the component with the component. In order to at least be able to approach a line contact, at least two end surface element are expediently axially parallel to each other and offset in the direction of the axis offset from one another mounted on the pole element.

The lateral surface of the end surface element can in the direction of its Drehbzw. Pivot axis be varied, for example, to form

Vertex areas, as described below under the third aspect of

Invention are described. It is understood that the end surface elements can also be varied in size. In particular, one and the same pole element associated end surface elements may have different size and / or cross-sectional contour.

In a variant in which the pole element, as explained in the second aspect, is pivotally mounted, the end face of the pole element coaxially to the pivot axis substantially circular to the

As such, the pole member may be curved with its end surface on the outer surface of the component when the induction coil unit performs an oscillatory motion relative to the component.

In a third aspect, which relates to a preferred embodiment of the first or second aspect, but also independent inventive

Has meaning in induction coil units with deviating from the first or second aspect features, it is an object of the invention, an induction coil unit for heating a rotationally symmetrical component, in particular a sleeve part, for example a

Tool holder, to create that easier than before

adapt different components to heat the component more evenly than before.

The above-mentioned object is achieved in the third aspect in that at least that intended for the plant or near-plant Part of the end face of each pole element as along the axis

elongated apex area towards each other towards the axis

is formed extending partial surfaces, wherein the radial height of the bounded by the partial surfaces achsnormalen cross-sectional area of the pole element is varied radially to the axis and / or the radius of curvature of

Vertex area in the achsnormalen cross-sectional area is varied and / or the width of the apex region in the circumferential direction of the component seen in the achsnormalen cross-sectional area along the axis is varied.

By varying the radial height and / or the radius of curvature and / or the apex width by the design of successive partial surfaces can be varied in a simple manner, the local magnetic resistance of the end faces and thus the magnetic flux in the component locally in a shunt to the on Component adjacent

Areas of the endface varies and be customized.

In a preferred embodiment which allows the pole element to also adapt to a contour of the component that changes in the direction of the axis, at least one or preferably all of the pole elements are formed as a stack of a plurality of mutually parallel pole rods movable radially relative to the axis. The axis of the facing ends of these pole rods form separate vertex areas, wherein the radial height of the bounded by the partial surfaces, axially normal cross-sectional areas is varied radially to the axis and / or the

Radius of curvature of the apex area in the axis normal

Cross-sectional areas is varied and / or the width of the apex area, seen in the circumferential direction of the component, in the axis normal

Cross-sectional area along the stacking direction varies at least between two adjacent in the stack pole rods. In this embodiment, not only the magnetic flux can be influenced, but also ensure that the pole element formed as a stack of pole rods can automatically adapt to the outer contour of the component. Such a pole element can for example rest on a conical outer jacket, even if the cone angle of the component varies from component to component or even within the component. The pile of pole pieces sufficiently approximates the peripheral contour of the component in practice, even if the generatrices of the end surfaces of the individual pole rods are axially parallel to the axis.

The variation of the end faces of the pole elements or pole rods, in each case seen in sectional planes normal to the axis, makes it possible to locally adapt the magnetic flux to a varying material cross section of the component to be heated. Especially with tool holders, the material cross section of the tool shank accommodating sleeve portion of the

Tool insertion side towards, d. H. The tool holder has a conical outer shell in this area, and accordingly, the circumferential length within which the magnetic flux encloses the cone also changes. In order to ensure a uniform heating of a component with in the direction of the axis increasing material cross-section, in particular a sleeve part with a conical outer shell, is

expediently provided that with increasing along the axis material cross-section of the component, the radial height of the bounded by the partial surfaces, achsnormalen cross-sectional area decreases radially to the axis and / or the radius of curvature of the apex area in the achsnormalen cross-sectional area increases and / or the width of the apex area, in the circumferential direction of the Component seen in the axis normal

Cross-sectional area increases.

In a particularly simple embodiment, the partial surfaces which are inclined towards one another and the top surface are essentially flat surfaces which have a trapezoidal, axially normal cross-sectional surface

limit. Alternatively, the surface areas and / or the crest surface which are inclined towards one another may be convexly curved surfaces which delimit an arcuate, limited, axially normal cross-sectional area. It is understood that the end face of the pole elements may be uniformly varied in the direction of the axis according to the principles explained above, regardless of whether the

Pole elements are integrally formed or formed as a stack of pole rods. However, the variation can be carried out stepped in poles constructed from pole rods.

The pole rods are displaceable against each other within the stack of each pole element and can be directly against each other or on

Guide surfaces of a predetermined pole piece of the stack to be guided transversely to the direction of displacement, as described for example in DE 10 2005 005 892 A1. Alternatively, however, the pole rods can also be guided on housing-fixed surfaces of the induction coil unit.

In operation, the pole rods should come into abutting contact with the outer jacket of the component. Suitable contact forces already generated for this purpose

Magnetic field in the AC excitation of the coils. However, it has been found that the magnetic field forces are sometimes insufficient to bring all the pole rods into secure abutment contact with the component, in particular when part of the pole rods already close the magnetic flux circuit while other pole rods are still spaced from the component. As described in DE 10 2005 005 892 A1, the individual pole rods can be assigned feed springs which are suitable for

sufficient, even pressure forces can provide. However, in this embodiment, care must then be taken that the pole rods for the removal of the component from the induction coil unit by suitable mechanisms back to the second position

can be pushed back, which leads to a relatively large construction cost, especially if the pole rods of each stack to follow a changing contour of the component.

In a fourth aspect of the invention, which includes a preferred embodiment of the first to third aspects, but also independent has patentable meaning, it is provided that in turn at least one or all of the pole elements are formed as a stack of several mutually parallel, radially to the axis relatively movably guided pole rods whose ends facing the axis form the end face of the pole member, and that as a stack of Polstäben trained Polelementen a drive device is assigned, which drives the pole rods together for the movement between the first and the second position, in particular a form-fitting, wherein in

Driving force transmission path between a drive member and at least a part number of pole rods a the drive to be transmitted limiting device, in particular a slip clutch, is arranged.

In such an embodiment, the pole rods of each stack

be pushed together by a manual or motorized drive member against the outer surface of the component in abutting contact. The driving force-limiting devices ensure that the contact of the individual pole rods to the component also comes about when the distance traveled by the individual pole rods is unequal due to the outer contour of the component. The drive device can be used both for the feed movement and for the return movement of the pole rods.

The drive member drives the pole rods via driving force transmission paths that are separate from each other, limiting the driving force

Devices included. The driving force transmission paths can be connected in series, as far as the slip clutches for then

staggered to be transmitted forces are designed. Also suitable are parallel transmission paths from the drive member to the individual pole rods, as here equal sized driving force limiting devices such. B. slip clutches can be used. In a particularly simple embodiment, it is provided that at least a part number of the pole rods of each pole element each have a linear toothing, each with a pinion meshes, which is in driving connection via a respective slip clutch with the drive member or another of the pinion. Conveniently, each pole rod to be driven comprises such a linear toothing, while slip clutches are provided only between such pinions, which have to complete or avoid additional paths according to the outer contour of the component. A simple and reliable design provides in this case that the pinion and the slip clutches are arranged on a common shaft parallel to the axis.

Expediently, such a shaft is provided for each pole element designed as a stack of pole rods. In particular, this wave is also used to guide the pole rods with. In order to drive the individual shafts from a common drive member, the shaft carries a gear wheel, which is concentric with one to the axis, with the

Drive member meshes in a rotary drive connection ring gear.

The general aim of the present invention is to design the induction coil unit so that it can be used as versatile as possible and thus for heating components with different outer contours in the area to be heated. One of the parameters in which the components, such as the tool holders, may differ is the length of the axial region to be heated. The receiving sleeve of the tool holder should be heated only over the length of that area in which the tool shank is held in a press fit. Not involved in the press fit areas of the receiving sleeve should not

Heating be charged to prevent long-term damage to the tool holder. The heating of unnecessarily large areas of the

Tool holder not only increases the energy required for heating, but also the energy requirement in the subsequent cooling and causes an extension of the cycle time when clamping and unclamping

Tool. In a fifth aspect, it is an object of the invention to show a way in which the region of the component to be heated in the direction of the axis can be limited to a desired degree. This aspect forms a preferred embodiment of the invention in the aforementioned first to fourth aspects, but also has independent inventive significance in induction coil units with other end surface configuration of the pole elements or other drive of pole rods

Pole members.

According to the fifth aspect of the invention it is provided that at least one or all of the pole elements are formed as a stack of a plurality of mutually parallel radially to the axis movably guided pole rods, whose axis facing ends form the end face of the pole member, wherein the pole member associated with a blocking device is, by means of which the movement of at least one of its pole rods with radial distance from the first position in the second position or a third position can be blocked.

The blocking device holds the blocked pole piece at a distance from the component, while the unblocked pole rods are either forcibly driven together or placed by spring force or magnetic force against the component, as described above. As far as the pole rods according to the fourth aspect of the invention in common

are driven, the driving force limiting device, so for example, the slip clutch of the blocked pole rod, ensures that the unblocked pole rods can be placed against the component.

By means of the blocking device, individual pole rods in the retracted and therefore inactive position can be blocked within the stack of pole rods. This allows selective setting of a

Heating profile even with the same axial length of the area to be heated on the component. In a preferred embodiment it is provided that at least the axially outermost in the stack located pole or in the stack axially outermost group of a plurality of adjacent pole rods is blockable. In this way, the axial thermal effect of the

Control induction coil unit in a simple way.

In a simple embodiment, the blocking device, adjacent to the stack of pole rods, has a movable blocking element cooperating with stop surfaces on the pole bars to be blocked

Counter stop surfaces for the stop surfaces of the pole rods to be blocked. The blocking element may be designed as a cam roller rotatably driven axially parallel to the axis, whose cam with the

Stop surfaces of the pole rods form cooperating counter stop surfaces. In order to be able to vary and adjust the number of pole bars to be blocked in a simple manner, the stop surfaces and / or counter stop surfaces, with respect to the direction of movement of the pole bars and / or the blocking element, can be staggered, so that they are used with different setting stroke.

Preferably, all blocking elements are in one

Forced drive connection with a common drive member, for example in the form that the blocking elements are designed as axially parallel to the axis rotatable cam rollers and have pinions which are coupled to a drivable by the drive member, concentric to the axis ring gear. The drive member may in turn be a manual drive member, but also a motor drive.

In contrast to induction coil units of the type known from DE 199 15 412 A1, the space intended for receiving the component to be heated and thus also the component mentioned therein is included

induction coil units according to the invention easily accessible, which facilitates handling. Furthermore, the axial height is reduced, which improves the possibilities. In the following the invention will be explained in more detail with reference to a drawing. Hereby shows:

Figure 1 is a perspective view of a variant of a

Induction coil unit for inductive heating of a tool holder for clamping and unclamping a tool;

Figure 2 is a partially broken view of the

Induction coil unit of Figure 1;

Figure 3 is an axial sectional view of the induction coil unit, taken along a line III-III in Figure 1;

Fig. 4 - 6 are schematic representations of unrollable on the components

pole elements;

Figure 7 is a schematic representation of a variant of

Induction coil unit of Figure 1;

Figure 8 is a perspective view of an induction coil unit for inductive heating of a tool holder for clamping and unclamping a rotating tool;

FIG. 9 shows a part of a sectional view through the induction coil unit, seen along a line IX-IX from FIG. 8;

Figure 10 is a perspective, teilwe ise broken view of

Induction coil unit, in which the housing and one of its coils is not shown for clarity; and

11 shows a schematic illustration of a plurality of pole rods of a stack of pole rods of the induction coil unit of FIG. 8. FIGS. 1 to 3 show an induction coil unit 1 with the aid of which a sleeve part 3, shown in broken lines in FIG. 2, of electrically conductive material, in this case steel, of a tool holder 5 can be heated by inductive means. The tool holder 5, which is essentially rotationally symmetrical with respect to its operating axis of rotation 7, hereinafter referred to as "axis", has a receiving opening 9 which is central to the axis 7 for the press-fit reception of a shaft 11, indicated otherwise by a dot-dash line, of an otherwise not shown working axis around the axis of rotation 7 rotating tool, for example, a drill or a milling cutter The tool shaft has, based on the inner diameter of the

cylindrical receiving opening 9, excess and has shrunk into the sleeve part 3. When heated, the sleeve part 3 widens, so that the tool shank 11 can be inserted into the receiving opening 9 or removed from it. After cooling, the in the

Receiving opening 9 inserted tool shank 11 held in a press fit in the sleeve part 3. The tool holder 5 can be part of a

Work spindle of a machine tool or on the sleeve part 3 axially facing away from side with a conventional spindle clutch, such. B. a steep tapered coupling or a hollow shaft coupling (HSK coupling), be provided.

The induction coil unit 1 has a substantially annular housing 13 made of electrical insulating material, here with

Rectangular outer contour, which is operatively axially displaceably held in a manner explained in more detail below on a particular vertical guide of a shrinking device.

The housing 13 encloses a possibly composed of segments yoke ring 17 of a soft magnetic, magnetic flux conductive, but electrically non-conductive material, such as ferrite, and carries on its inner ring side at equal angular intervals about the axis 7 around arranged, preferably wound from high-frequency strand coils 19th , The coils 19 are in even number at equal angular intervals and lying in a common axis normal plane

Coil axes arranged around the axis 7 around. The coils 19 are, based on their diameter, flat and radial to the axis 7

Coil axis arranged. It goes without saying that the above-described "transverse field" can also be produced with fewer coils, but also more coils than would be the case with the number of pole elements.

Each of the coils 19 encloses a pole element 21 of soft magnetic, magnetic flux conductive, but electrically non-conductive material, such as ferrite, which on the housing 13 and / or the yoke ring 17 and / or the coil 19 and in the following explained in more detail according to the yoke ring 17 Way is guided displaced. Each pole element 21 in this case penetrates the coil 19 and projects into a receiving space 23 (FIG. 2) bounded by the coils 19 for receiving the sleeve part 3 of the tool holder 5. The pole elements 21 are radially up to near the axis 7 in the manner explained in more detail below pushed, so that they can rest in a first position on sleeve parts 3 with very different diameters. The pole elements 21 are movable away from the axis 7 into a second radially outer position by a drive, which will be explained in more detail below, in which the sleeve part 3 can be inserted into the receiving space 23 or removed from the receiving space 23.

The induction coil unit 1 of Figures 1 to 3 is by means of a handle 65 along a vertical guide column 67 here relative to the

Tool holder 5 is displaceable. The tool holder 5 is with the

Displacement direction of the guide column 67 parallel axis 7 fixed on a holder 69. The guide column 67 and the holder 69 form, as indicated by the common base 71, a device unit, so that the induction coil unit 1 on the sleeve portion 3 of the tool holder. 5 can be placed, such that the sleeve portion 3 in a

Receiving space 23 of the induction coil unit 1 is immersed.

In the interior of the yoke ring 17 is an even number of coils 19 with a radial coil axis, here four coils 19, arranged at equal angular intervals about the axis 7 around. The yoke ring 17 and the coils 19 are of plate-shaped, also made of magnetically conductive, electrically non-conductive material, for. As ferrite, existing pole elements 21 passes through, wherein the plate planes of the pole elements 21 in radial planes, which include the axis 7, are.

The pole elements 21 are slidably guided in guide elements 73, which at the same time also each carry one of the coils 19, radially to the axis 7, in such a way that they extend with their in the direction of the axis 7

End surface can create in a first position along a generatrix of the conical outer shell of the sleeve portion 3 and are lifted in a retracted second position of the outer shell.

Each of the pole elements 21 is provided with a linear toothing 27, here along a narrow peripheral edge, which meshes with a drive pinion 51. The pinions are, as the figures 1 and 2 best show, all via a gear transmission chain 75, here of bevel gears with each other and coupled with a handling rotary handle 35 with each other. On the

Handling rotary handle 35, all pole elements 21 can be moved radially simultaneously.

The synchronous mobility of the pole elements 21 relative to the axis 7 allows the adaptation of the induction coil unit 1 to tool holders with different outer diameters. In order to heat also tool holder, the receiving sleeve 3 have different outer cone angle, the guide elements 73 are pivotally mounted on the housing 13 about a transverse, but in particular perpendicular to the axis 7 containing radial planes. The indicated at 77 pivot axes are equiaxed to the axes of rotation of the pinion 51 and lie in one

common plane normal to the axis 7. In this way, the

Inclination angle of the end face 43 of each pole member can be varied by pivoting the guide member 73 about the axis 77. The

Guide elements 73 are in turn coupled via a chain of gear drives or the like. With each other and a Einstelldrehknopf 79, which allows the pole elements 21 together to incline so that the end surface 43 in line or planar contact contact along a generatrix of the conical outer shell of the receiving sleeve. 3 comes.

The dimensions of the end face 43 of each pole element 21 is shorter in the direction of the axis 7 than the axial area of the receiving sleeve 3 intended for the interference fit engagement. In order nevertheless to inductively heat the entire region of the sleeve section 3 fixed for the press fit, this is

Induction coil unit 1 in turn guided against the predetermined by the handle 65 basic position. The handle 65 is connected to a slidable on the guide column 67 slide 81. The induction coil unit 1 is in turn guided in the direction of displacement of the carriage 81 and thus movable parallel to the axis 7, which is indicated in Figure 1 by a double arrow 83. The carriage 81 carries a rack 85 which meshes with a pinion 89 driven by an electric motor 87. A controller shown at 91 in FIG. 2 controls the

Electric motor 87 so that the induction coil unit 1 performs an oscillating movement along the axis 7, in which the end surfaces 43 of the pole elements 21 slide along the outer shell of the receiving sleeve 3 and for an oscillating displacement of the flow area of the

Magnetic flux along the receiving portion 3 provide. In this way, even a comparatively large press-fit area in the axial direction can be uniformly heated with pole elements which are relatively narrow in the axial direction.

The controller 91 outputs the frequency and the amplitude of the axial

oscillating movement of the induction coil unit 1 before. It goes without saying that the controller 91 can also specify a non-linear sequence of movements, so that the instantaneous dwell time of the pole elements 21 relative to the tool holder 5 for compensation of a longitudinal axis 7th

non-uniform heating can be used.

The illustrated drive for the oscillatory movement of

Induction coil unit 1 in the direction of the axis 7 by means of a pinion rack arrangement is merely exemplary. Other

Drive mechanisms, for example in the form of an eccentric drive or a hydraulic or pneumatic oscillating drive are conceivable.

The axial oscillating drive makes it possible to increase the axial area of the tool holder to be heated without overdimensioning the induction coil unit. In order to uniformly heat the tool holder 3 in the circumferential direction, the holder 69, as indicated at 91 by an arrow, may be driven to rotate about the axis 7.

The pole elements 21 need only initially by means of

Handling button 35 are placed against the outer surface of the receiving sleeve 3. When the coils 19 are switched on, the magnetic field then generated ensures that the end faces 43 of the pole elements 21 in FIG

Stay in contact with the outer jacket.

The intended for the swivel angle handling knob 79 may be omitted if necessary. With sufficiently smooth gear couplings, it is sufficient to provide the pole elements 21, if necessary, tilted against the receiving sleeve 3. The magnetic attraction force present when the coils are energized, in conjunction with the oscillatory movement of the induction coil unit 1, ensures that the guide units 73 automatically move into a position

pivot, in which the end surface 43 rests linearly or flat on the receiving sleeve 3. The end surfaces 43 may have the cross-sectional configuration explained below with reference to FIG. 11. It can also be provided in a variant that the plate-shaped pole elements 21 are formed as a stack against one another radially displaceable pole rods to the axis, as indicated by dash-dotted lines in Figure 3. The blocking function explained below with reference to FIGS. 8 to 10 can also be implemented in the variant of FIGS. 1 to 3.

During the oscillation movement, the pole elements 21 slide with their end faces 34 in the direction of the axis 7 along the generatrix of the

This may cause wear on the pole elements 21 and / or the sleeve section 3. In order to reduce the wear, as the embodiment of Figure 4 shows schematically, the pole member 21 in the region of its axis 7 adjacent to the end about an axis 93 rotatable on the

Pole 21 mounted wheel 95 may be provided, which indicated with its peripheral surface 97 at the indicated by a double arrow 99

Oscillatory movement along the outer shell of the sleeve portion 3 rolls. The axis of rotation 93 extends transversely to the axis 7 in an axis 7 axis normal to the plane. The wheel 95 is also made of a

Magnetic flux conductive material, for. As ferrite, and forms the actual

As already explained above, the pole element 21 is displaceably guided transversely to the axis 7 corresponding to the double arrow 101 and is held in abutting contact with the sleeve section 3 due to the magnetic forces. An additional swiveling

Storage of the pole element 21, as explained with reference to FIGS. 1 to 3, is not required.

FIG. 5 shows a variant of a pole element 21 extending from the

Pole element 21 of Figure 4 differs essentially only in that arranged as the end face of the pole element forming element in a spherical chamber 103 all sides rotatably guided ball 105 is. It is understood that the chamber 103 is also suitable for guiding the wheel 95 of FIG.

Not shown in detail are embodiments in which a plurality of wheels 95 or balls 105 are arranged offset in the direction of the axis 7 in order to achieve an at least approximately linear contact with the sleeve portion 3. It is understood that if necessary, several wheels or balls in the direction of their axes of rotation can be arranged side by side.

Figure 6 shows a further variant of a Poleiements 21, the end surface 34 is designed circular segment. Centric to the end surface 34, the pole member 21 is pivotally mounted about an axis 107 on a guide 109. The guide is displaceable radially to the axis 7 in the direction of the double arrow 111, so that the end face 34 of the pole element can be brought into abutting contact with the outer shell of the sleeve portion 3 and during the oscillatory movement in the direction of the double arrow 113 am

Outer jacket of the sleeve portion 3 rolls.

In the embodiments of Figures 4 to 6, the coils are not shown; However, they enclose the pole element, as this

was explained before.

In the following variants of the induction coil unit will be explained.

Equivalent components are denoted by the reference numerals of Figures 1 to 6. It is understood that the variants illustrated component of both the preceding versions explained as well as the

subsequent versions.

In the embodiments explained above, the pole elements generate a magnetic flux directed in the circumferential direction of the tool holder. As FIG. 7 shows in a schematic illustration, the idea of the heating area of an induction coil unit 1 can be explained by a

Oscillation movement, double arrow 83, in the direction of the axis 7 of a Tool holder 5 realize in other coil configurations. In FIG. 7, a coil 19 enclosing the sleeve section 3 coaxially is terminated by pole elements 21 at its two axial end faces. The pole elements 21 are supplemented on the outside of the coil 19 by a yoke ring 17 to a magnetic circuit which limits the magnetic field in the region of the outer shell of the sleeve portion 3 substantially to the region axially between the two pole elements 21. The axial distance of the pole elements 21 is smaller than that provided for the press fit of the tool shank in the receiving sleeve 3 area and is characterized by the

Oscillation movement of the induction coil unit 1 along the arrow 82 increases to the desired level.

The pole elements 21 may be pole disks, as described in DE 199 15 412 A1. However, the pole elements 21 can also consist of a star arrangement of radially movable pole rods in order to ensure contact contact with the axis 7 adjacent end surfaces 43. The pole element 21 located remotely from the free front end of the sleeve section 3 may possibly be dispensed with.

FIGS. 8 to 10 show a further variant of one

Induction coil unit 1 with details of the configuration of the pole elements 21. Measures for oscillating movement of the induction coil unit 1 relative to the sleeve portion 3 of the tool holder 5 are not shown, but may be present. Alternatively, the measures explained with reference to FIGS. 8 to 11 can also be provided in the variants of FIGS. 1 to 3 and 7.

In contrast to the previously described pole elements, the pole elements 21 in the variant of FIGS. 8 to 11 are stacked in the direction of the axis 7 of stacked pole rods 25, here in each case 6 pole rods 25, which can be moved radially together but radially relative to one another to the axis 7 are displaceable. It is understood that too the pole elements of the above-explained induction coil units can be constructed as a stack of pole rods.

Each of the pole rods 25 comprises a rack-like linear toothing 27 which meshes with a pinion shaft 29 associated in common with the pole rods 25 of each rod. The pinion shafts 29 are arranged axially parallel to the axis 7 and each carry a drive gear 31, which in turn meshes with a coaxially rotatable in the housing 13 to the axis 7, common first ring gear 33. The ring gear 33 carries an accessible outside the housing 13 hand lever 35, by means of which the ring gear 33 can be rotated and thus the pole elements 21 can be moved together via the pinion rollers 29 radially to the axis 7.

In operation, the tool holder 5 is fixed to a receptacle or a holder, not shown, while the induction coil unit 1 along a likewise not shown, mostly vertical

Guide rail equiaxial to the axis 7 of the tool holder

slidably guided in order to introduce the tool holder 5 in the receiving space 23 of the induction coil unit 1 can. The recording may be stationary, but also in turn arranged to be movable. In a movable recording, alternatively, the induction coil unit 1 may be arranged stationary. The same applies to the preceding ones

explained embodiments. On the tool insertion side of the

Tool holder 5 carries the induction coil unit 1 a stop 37 (Figure 8), which in the operating position on an axial end face of the

Tool holder 5 is applied and for a reproducible position of

Induction coil unit 1 relative to the tool holder 5 provides. The stop 37 has an obliquely to the axis 7 adjustable, but lockable guided stop finger 39, as already explained in DE 10 2005 005 892 A1. After the induction coil unit 1 has been brought to the abutment of the stop 37 to the tool holder 5, the pole elements 21 are moved by means of the hand lever 35 in abutting contact with the outer shell of the sleeve portion 3. The subsequent excitation of the coils 19 with AC induced in the sleeve portion 3 a in

Circumferential magnetic flux that heats the sleeve portion 3 for clamping or unclamping the tool shaft. Cooling air or cooling fluid is conducted via one or more nozzles against the heated tool holder 5 via a coolant connection which can be seen in FIG. 1 at 41, which is thereby cooled to a temperature which is not hazardous to touch.

The tool holder 5 has, as Figure 10 shows, a conical outer shell, while the receiving opening 9 forming inner shell is cylindrical. From the tool insertion side located at the top in FIG. 10, therefore, both the thickness of the material cross-section and the outer one increases

Peripheral length of the receiving sleeve 3 in the direction of the axis 7 too. The changing dimensions affect the eddy current excitation in the receiving sleeve 3 and thus the local heating, which is without

Countermeasures would change in the axial direction.

In order for a uniform in the direction of the axis 7 heating the

To provide receiving sleeve 3, the pole elements 21 end face areas 43, whose cross-sectional contour, relative to the axis 7 normal

Levels, in the direction of the axis 7 at least between two adjacent pole pieces 25 changes.

FIG. 11 schematically shows plan views of pole rods 21, seen in FIG

Direction of the axis 7. FIG. 11a shows the plan view of the pole pin in the area of the tool insertion side on the smallest diameter portion of the outer shell of the receiving sleeve 3, while FIG. 11c shows the contour of the largest portion of the outer shell

adjacent pole pin 21 shows. FIG. 11b shows one of the pole pins 21 arranged in the stack between the uppermost and the lower pole pins. The contour of each end surface region 43 is defined by two partial surface regions 45 (FIG. 1a) which are inclined toward one another and merge into one another in a direction of the axis 7 extending, intended to rest on the outer surface of the receiving sleeve 3 of the tool holder 5 apex area. In the illustrated embodiment, the lateral surface portions 45 and the surface of the apex portion 47 are flat and define a trapezoidal cross section whose side surface angle α in the direction of the axis 7 of the smallest diameter portion of the

Outer jacket decreases to the largest diameter area. The width of the flat vertex surface is, seen in the circumferential direction of the

Tool holder 5, from pole to pole about constant, but the radial height H decreases accordingly.

As indicated in the figures 1 1a to 11c by dotted lines, the planar vertex surface 47 may also be replaced by a curved vertex surface 47 '. If necessary, the curvature can also extend over at least part of the partial surfaces 45. The radius of curvature increases in the direction of the expanding cone-shaped outer shell of the sleeve section. In this configuration, the pole rods 21 can form rounded end surface regions 43 at least in the apex region. Further alternatively, the inclination angle α from pole to pole to be equal, in which case the height H decreases in the direction of the widening conical surface of the outer shell, as z. B. in Figure 11 a at 47 "is additionally indicated for the bottom pole relative to the contour of the top pole.

Due to the variation of the end surface cross section of the pole rods, the transition of the magnetic flux from the pole rod to the tool holder is varied and thus the magnetic flux strength and, accordingly, the

Eddy current amplitude in the contact area of the pole rod. It is understood that in the direction of the axis 7 varying Endbereichsquerschnitte can also be applied to one-piece Polelementen, so Pol elements that are not constructed segmented from stacked pole rods. The induction coil unit 1 should be as versatile as possible

Tool holders can be used with different cone angle of their outer sheath. To ensure that the end surface area 43 of each pole bar 25 taken by itself, even with variation of

Konuswinkels comes into abutting contact with the outer jacket, the pinion roller 29 carries on a common, fixedly connected to the drive wheel 31 shaft a plurality of rotatably mounted on the shaft 49 single pinion 51, each with a linear toothing 27 of the pole rods 25 mesh. The rotatably seated on the shaft 49 pinion 51 are each about one

Slip clutch (not shown) with either the shaft 49 or an adjacent pinion 51 coupled. The pinion shaft 29 is therefore not only able to drive all the pole rods 25 together, but also permits relative displacements between pole rods 25, the pinion 51 of which is driven via a slip clutch.

It is understood that all pinion 51 can be coupled via friction clutches with the shaft 49, but that in an individual case at least a portion of the smallest diameter in the region of the outer shell of the

Sleeve section 3 adjacent Polstabs 25, here the top pole, the associated pinion can also be positively coupled to the shaft 49, while others the larger diameter portion of the

Outer shell associated pinion 51 limited frictionally, z. B. via slip clutches, may be connected to the shaft 49. The

Slip clutches may be effective between the pinion and the shaft 49, so that these pinions are driven in parallel with each other. Also, a serial arrangement is conceivable for friction clutches, if their

Release torque decreases from pinion to pinion in the direction of the widening conical outer shell of the receiving sleeve 3.

The region of the receiving sleeve 3 of the tool holder 5 to be flooded by the magnetic flux should expediently be limited to the axial region in which the tool shank is held in a press fit in order, on the one hand, to load the tool holder 5 only slightly thermally and on the other hand to reduce the cooling effort and the time required for cooling. In conventional induction coil units, the area flooded by the magnetic flux is determined by the axial dimensions of the pole elements causing the magnetic flux. In order to change the number of applied in operation on the receiving sleeve 3 pole rods 25 and thus the effective axial height of the pole elements 21 are in

Circumferentially arranged laterally of the pole elements 21 cam rollers 53 rotatably, the cam 55 with at the individual pole rods 25th

molded stop surfaces 57 cooperate. The cams 55 can be swiveled into their displacement path when the pole rods 25 are radially retracted from the tool holder 5 and thus block the feed movement of the pole rod 25 towards the tool holder 5. The blocked pole rods 25 are then blocked for the flow.

Each of the camshafts 53 carries a drive gear 57 which meshes with a second ring gear 59 rotatably mounted in the housing 13 coaxially with the axis 7 rotatably. The ring gear 59 is over a

Intermediate gear 61 driven by a hand knob 63, so that mutually corresponding pole rods 25 of the individual pole elements 21 are jointly blocked or releasable. It is understood that the manual operation button 63 as well as the hand lever 35, if necessary

Electromotive drives can be replaced.

The cams 55 and / or abutment surfaces 57 are suitably staggered so that they depend on the rotation of the

Camshaft 53 successively come into engagement and accordingly a variable number of pole rods 25 can be blocked.

Conveniently, the staggering of the cam 55 and the

Stop surfaces 57 chosen so that starting with the on

diameter-largest portion of the outer shell of the receiving sleeve 3 adjacent, bottom Polstab the pole rods are sequentially blockable. It is understood, however, that possibly also between the end-side Polstäben 25 arranged pole rods for controlling the heat distribution in a central region of the stack can be selectively blocked.

Claims

claims

Induction coil unit for heating a relative to an axis (7) rotationally symmetrical component made of electrically conductive material, in particular a sleeve part which holds an elongated object in an axially concentric receiving opening in an interference fit, preferably for heating the sleeve part (3) of a tool holder (5) , which holds a shaft of a rotary tool, in particular a drilling or milling tool, in a press fit in its central axis to the axis of rotation Aufnahmeäffnung comprising

one to the axis (7) centered receiving space for the component

(3)

at least one pole element (21) made of a material having soft magnetic, magnetic flux conducting properties,

at least one AC-energizable coil (19) for generating magnetic flux in the at least one pole element (21),

wherein the at least one pole element (21) has an end face (43) which is substantially radially facing the axis (7) and which is in abutting contact or in close contact with the outer circumferential face of the component (3),

characterized in that

a drive arrangement (85, 87, 89) is provided which comprises at least the at least one pole element (21) and a holder (69) for the component (3) at least during a part of the period in which the at least one coil (19) Alternating current is fed, relative to each other moving in the direction of the axis (7) longitudinally movable and / or about the axis (7) rotatably drives.

Induction coil unit according to claim 1, characterized in that a plurality of distributed around the axis distributed, in particular at equal angular intervals distributed pole elements (21) are provided, the radial to the axis (7) are movably guided on the unit (1) and between a position near the axis (7) and a position remote from the axis are movable and with their axis substantially radially facing end surfaces (43) in the axis of the near Position at least in a portion of its axial height in abutting contact or almost abutting contact with the outer peripheral surface of the component (3).

Induction coil unit according to claim 2, characterized in that at least one coil (19), which can be fed with alternating current, for generating magnetic fluxes in the pole elements (21), in particular a plurality of these coils (19), are provided and the end faces (43) of the pole elements (21). in the first position at least in the partial region of its axial height along a generatrix of the outer peripheral surface of the component in abutting contact with the outer circumferential surface of the component.

Induction coil unit according to one of claims 1 to 3, characterized in that the axial height of the or the pole elements (21) is smaller than the axial region of the component (3) to be heated.

Induction coil unit according to claim 1 or 2, characterized in that a coil enclosing the component (19) is provided and arranged on at least one axially located side of the coil (19), preferably both axial sides of the coil, one or more of the pole elements (21) are.

Induction coil unit according to one of claims 1 to 5, characterized in that the at least one coil (19) and the at least one pole element (21) form a relative to the holder movable unit and the drive assembly, this unit and the support in the direction of the axis relative to each other in an oscillating motion drives. Induction coil unit according to one of claims 1 to 6, characterized in that the drive arrangement is associated with a controller (91), the relative speed of the relative movement and / or the current strength of the at least one coil alternating current depending on the current position of the at least one pole element relative to the bracket controls.

Induction coil unit according to one of claims 1 to 7, characterized in that at least one pole element (21) of the axis (7) adjacent at least one about a transverse to the axis (7) extending axis of rotation (93) rotatable or pivotable end surface element (95; a material having soft magnetic, magnetic flux conducting properties, which forms a around the rotation axis (93) curved around, in particular coaxially to the rotation axis circular curved on the outer peripheral surface of the component (3) in abutting contact abwälzbare end surface.

Induction coil unit according to claim 8, characterized in that the end surface element as a wheel (95) or roller or ball (105) is formed.

Induction coil unit for heating a relative to an axis (7) rotationally symmetrical component made of electrically conductive material, in particular a sleeve part which holds an elongated object in an axially concentric receiving opening in an interference fit, preferably for heating the sleeve part (3) of a tool holder (5) , which holds a shaft of a rotary tool, in particular a drilling or milling tool, in a press fit in its receiving opening, which is centric to the axis of rotation

a center of the axis (7) receiving space (23) for the component,

a plurality of arranged around the axis distributed around, in particular distributed at equal angular intervals arranged pole elements (21) made of a material with soft magnetic, magnetic flux conducting properties,

at least one coil (19), which can be fed with alternating current, for generating magnetic fluxes in the pole elements (21), in particular a plurality of these coils (19),

wherein the pole elements (21) are movably guided radially to the axis (7) on the unit and are movable between a first position near the axis and a second position remote from the axis, and

wherein the pole elements (21) of the axis (7) have substantially radially facing end surfaces (43) in the first position preferably at least in a partial region of its axial height along a generatrix of an outer peripheral surface of the component in abutting contact or almost in abutting contact with the outer peripheral surface of the component, in particular according to one of claims 1 to 9,

characterized in that

the pole elements (21) are movably guided in each case in a guide element (73) between the first and the second position and in that the guide elements (73) each extend about a common axis transverse to the axis (7) and in particular in a direction normal to the axis (7) Level extending pivot axis (77) are pivotally mounted.

Induction coil unit according to claim 10, characterized in that the guide elements (73) for a same direction pivoting movement via a transmission with each other and in particular also with a common drive member (79) are coupled.

12. induction coil unit according to claim 10 or 11, characterized in that the pole elements (21) are formed as a stack of several mutually parallel radially to the axis relative to each other movably guided pole rods (25) whose axis facing the ends of the end face of the pole element ( 21), the stack of pole pieces (25) of each pole element (21) on each one of the guide elements (73) is displaceably guided.

13. induction coil unit according to one of claims 10 to 12, characterized in that each pole element (21 a) has a linear toothing (27 a) which meshes with a on the guide element (73) mounted drive pinion (51 a), and the drive pinion (51 a) with a drive motor (35a) are in drive connection.

14. induction coil unit according to one of claims 10 to 13, characterized in that the end face (43) of the pole element (21) is curved gleichaxachsig the pivot axis (107) in a substantially circular around the pivot axis (107) around.