EP1523396B1 - Method and device for chucking rotationally symmetrical bodies - Google Patents

Abstract

The invention relates to a method for chucking a rotationally symmetrical body (10) for machining purposes, according to which the first face (12) of said body (10) is pulled against a centring support element (72) by means of a tractive force (F1), which is exerted on the first face (12) of the body (10) along the extension of the rotational axis (19, 19') of said body (10). The invention also relates to a device for chucking a rotationally symmetrical body (10) in order to machine said body, the device comprising a support element (72), against which the body (10) can be pulled and a tractive anchor (64), which can engage with and pull the body (10) axially and concentrically in relation to the rotational axis (19, 19') of the body to be chucked. The positioning of the tractive anchor (64) is configured in such a way that the latter (64) is axially guided with radial play (66) for the axial tractive displacement. The tractive force (F1) of the tractive anchor (64) can preferably be adjusted. The invention also relates to a rotationally symmetrical body (10), in particular a rotor, which on a first face (12) comprises a coupling unit (18) that is centred with the rotational axis (19) of the rotor and a bearing zone (22) comprising at least three bearing surfaces (24) that are arranged concentrically with the rotational axis (19, 19').

Description

Technical area

The invention relates to the field of machining of rotationally symmetrical bodies, especially of rotors, such as compressor wheels, turbine wheels, compressors and the like. In particular, it relates to a method for clamping rotationally symmetrical body according to the preamble of method claim 1, and an apparatus for clamping rotationally symmetrical body according to the preamble of the device claim. 7

Such a method and apparatus are known from the document US-A-4,986,704 known.

State of the art

Many rotationally symmetrical bodies, which are later used as components in machines or otherwise used, such as pipes, shafts, spindles, wheels, rotors, are first produced in the form of blanks, which have the basic shape of the desired body. The blanks can be made, for example, by casting, sintering, injection molding, forging, etc. In order to bring the blanks in the desired final shape, it usually still requires a machining post-processing, such as cutting, drilling, turning, milling, grinding, etc. For this purpose, the bodies are clamped by means of chucks in a corresponding machine. The chuck usually comprises a collet, which generally has at least three clamping jaws for rotationally symmetrical body. However, a centered clamping of rotationally symmetrical bodies is only limitedly possible with these commercially available chucks. The reproducibility of the tensioning process is therefore generally unsatisfactory and leads to significant errors in the machining of a workpiece in several tension sequences. In precision cast, rotationally symmetrical workpieces, these errors can lead to intolerable unbalance behavior.

Presentation of the invention

It is therefore an object of the invention to provide a method and an apparatus with which the rotationally symmetrical body can be reproducibly and with high precision coaxial, stable, clamped.

This object is achieved by a method having the features of the method claim 1, and a device according to the features of the device claim 7. Vorteilhalfte embodiments are described in the subclaims.

In the inventive method for clamping a rotationally symmetrical body for the purpose of its machining, the rotationally symmetrical body is pulled with its first side by means of a tensile force acting in extension of the axis of rotation of the body on the first side of the body against a centering acting support element. By fixing the rotationally symmetrical body by means of acting along its axis of rotation tensile force on the centering acting support member of the body can not be misjudged, as is otherwise the case in the working with laterally acting pressure jaws.

A centering effect receives the support element, for example, by acting on the support element with a tensile force counteracting the spring force. Is the spring force slightly smaller than the tensile force and so dimensioned that upon impact of the body on the Supporting element, the support element first yields in the axial direction, so it is possible even more precisely centric to pull the rotationally symmetrical body against the support element and so to fix. Very simply, the tensile force can be transferred to the body with the aid of a kind of tie rod, which is simply and quickly connected to the body, for example, by means of a quick coupling.

It is particularly advantageous to move the tie rod with radial play axially and concentrically with the axis of rotation of the rotationally symmetrical body. The radial play causes, particularly advantageous in interaction with the spring force acted upon support element, an accurate, centric fixation against the support element without misjudging the body.

If the body additionally with a support region, which is arranged axially spaced from the first side of the body and aligned the same as the first side, pulled against an axially stationary centering, we obtain an even more stable fixation of the body, the exact centric position of the body also stabilized against vibrations. This is very advantageous, especially in processes in which the body is acted upon with great force. The centered clamping of the body is the more stable the closer the centering device engages at the location where the machining process engages

Very good clamping results are obtained when one chooses spring force, tensile force and the design of the support element and optionally centering depending on the body to be clamped.

If the rotationally symmetrical body to be clamped is a rotor with molded-on blades, then a particularly stable clamping is obtained if a centering device is selected whose centering surfaces engage in finger-like manner between the blades. Under certain circumstances, depending on the material and the blade shape, but it can also be more advantageous to work with a centering device whose centering surfaces cooperate with the blade edges.

The method described above for clamping a rotationally symmetrical body for the purpose of its machining can be carried out with a device comprising a tie rod, which is axially guided in a wall forming the support of the body of the device with radial play concentric with the axis of rotation of the body to be clamped on this can attack.

A particularly good centering can be achieved, with a support element, which is in the axial direction, preferably free of play, movable and which is supported in particular resiliently against a fixed stop of the device. It when the support element is either bell-shaped, so that it can surround a clamped body centering, or if it is in the form of a dome or a tip, the / then centering in a recess or concave bearing surfaces of the clamped Body can intervene.

If the tie rod is provided with a coupling device, which is preferably designed in the form of a quick coupling and connectable to a coupling unit of the body to be clamped, then the body to be clamped can be clamped very easily and above all quickly in the device and also be removed from the device again.

If the support element is provided with support surfaces arranged concentrically to the axis of rotation of the body to be clamped, this favors a central clamping. Particularly good results are achieved with a support element whose support surfaces are inclined against the axis of rotation. For certain rotationally symmetrical bodies, it may be advantageous if the support surfaces touch at least along a defined outer circumference and form an annular support surface. For other rotationally symmetric Body may be cheaper if the support surfaces are evenly distributed over the circumference and extend more radially.

An axially spaced from the support element arranged stationary centering, which is arranged with concentric with the axis of rotation of the body to be clamped and preferably provided inclined against the axis of rotation centering surfaces, allows an even safer clamping of rotationally symmetrical bodies.

Particularly good clamping results can be achieved with an inventive device in which the tensile force of the tie rod and the tensile force counteracting the spring force can be adjusted. Also to very good Einspannergebnissen wear replaceable, differently designed support elements and interchangeable with existing centering, differently configured centering. Adapted to the body to be clamped (geometry, weight, etc.) then support element, centering, spring force and tensile force can be selected. Very favorable, especially for rotationally symmetrical bodies such as rotors with blades, are e.g. Centering with uniformly distributed over the circumference centering surfaces that extend finger-like from a defined outer circumference to a defined Innumfang against the axis of rotation. Of course, the number of centering surfaces must then be matched to the number of rotor blades, so that the centering surfaces engage between the rotor blades.

Particularly suitable for clamping according to the inventive method in the inventive device are not inventive, rotationally symmetrical body, in particular rotors having on a first side a centric with its axis of rotation coupling unit and a support area with at least three concentric with the axis of rotation arranged bearing surfaces. The bearing surfaces are aligned away from the center of the body to the first page. The coupling unit can be claimed to train and can be particularly easy to connect with a counter-configured coupling device. For a quick clamping and unclamping, it is advantageous if the coupling unit is designed in the form of a quick coupling. Very easy to realize this with a Coupling unit, which has substantially the shape of a concentric hollow cylinder or hollow polygon arranged in the body. In an advantageous embodiment, the coupling unit is designed as the one half of a bayonet closure, in another advantageous embodiment than the one half of a screw connection. Advantageously, the bayonet lock a stop as over-rotation protection, as is known for bayonet locks. A rotationally symmetrical body can be clamped particularly precisely if the bearing surfaces are inclined towards the axis of rotation and enclose an obtuse angle α with the axis of rotation in the range from 100 ° to 170 °, preferably 120 ° to 150 ° and in particular 135 °. For this purpose, however, the bearing surfaces can also be designed as surfaces that are convex or concave curved toward the axis of rotation and toward the first side. Depending on the weight and geometry of the rotationally symmetrical body, it may be advantageous if the bearing surfaces are connected to each other and form a closed annular surface.

If at least three concentric centering areas are provided on the second side of the body, the support surfaces of which are aligned against the first side of the body and preferably inclined towards the axis of rotation, then the body can also be clamped with the aid of a centering device and thus fixed particularly well. Again, it has proved to be advantageous if the bearing surfaces are formed inclined relative to the axis of rotation. The angle of inclination β for the bearing surfaces of the centering regions is in the range of 15 ° to 100 °, preferably 20 ° to 60 ° and in particular 30 °. Another good possibility is to form these contact surfaces as surfaces which are convex or concave in relation to the axis of rotation. Again, it may be advantageous if the bearing surfaces are connected to each other and form an annular surface.

If the body has a marking that always allows the same orientation of the body in space, it can always ensure the same and precise clamping during re-clamping.

The easiest way is the rotationally symmetrical body produced as a cast body. In this case, the coupling unit, the bearing surfaces and preferably, if present, even the marking can already be produced essentially simply by casting and inexpensively.

Also rotors, in particular integrally formed Laufschaufein can be made very advantageous in the form of rotationally symmetrical body described above. Particularly advantageous in such rotors is to arrange the bearing surfaces at least on the second side of the body between the blades and to integrate the coupling unit preferably in the hub.

Brief description of the drawings

Fig. 1

im Schnitt entlang seiner Rotationsachse einen nicht erfindungsgemässen rotationssymmetrischen Körper;

Fig. 2

im Schnitt entlang seiner Rotationsachse eine andere Ausführungsform eines nicht erfindungsgemässen rotationssymmetrischen Körpers und zwar in Form eines Rotors;

Fig. 3

den rotationssymmetrischen Körper aus Fig. 2 obere Bildhälfte im Schnitt entlang der Linie III-III;

Fig. 4

den rotationssymmetrischen Körper aus Fig. 2 untere Bildhälfte im Schnitt entlang der Linie III-III;

Fig. 5

ebenfalls im Schnitt entlang seiner Rotationsachse eine weitere Ausführungsform eines nicht erfindungsgemässen rotationssymmetrischen Körpers in Form eines Rotors;

Fig. 6

die erfindungsgemässe Vorrichtung zum Einspannen rotationssymmetrischer Körper in einer Teilansicht im Schnitt entlang der Rotationsachse der einzuspannenden Körper;

Fig. 7

den rotationssymmetrischen Körper aus Fig. 2 eingespannt in der in Fig. 6 dargestellt erfindungsgemässen Vorrichtung;

Fig. 8

eine Ausführungsform einer zur erfindungsgemässen Vorrichtung gehörenden Zentriereinrichtung in Seitenansicht gemäss Pfeilen VIII- VIII in Fig. 6; und

Fig. 9

eine weitere Ausführungsform einer Zentriereinrichtung in analoger Darstellung zu Fig. 8.

In the following, the subject invention will be explained in more detail with reference to preferred embodiments, which are illustrated in the accompanying drawings. It shows purely schematically:

Fig. 1

in section along its axis of rotation a non-inventive rotationally symmetrical body;

Fig. 2

in section along its axis of rotation another embodiment of a non-inventive rotationally symmetrical body and in the form of a rotor;

Fig. 3

the rotationally symmetrical body Fig. 2 upper half of the picture in section along the line III-III;

Fig. 4

the rotationally symmetrical body Fig. 2 lower half of the picture in section along the line III-III;

Fig. 5

likewise in section along its axis of rotation a further embodiment of a non-inventive rotationally symmetrical body in the form of a rotor;

Fig. 6

the inventive device for clamping rotationally symmetrical body in a partial view in section along the axis of rotation of the body to be clamped;

Fig. 7

the rotationally symmetrical body Fig. 2 clamped in the in Fig. 6 illustrated inventive device;

Fig. 8

an embodiment of a device according to the invention associated centering device in side view according to arrows VIII- VIII in Fig. 6 ; and

Fig. 9

a further embodiment of a centering device in an analogous representation to Fig. 8 ,

The reference numerals used in the drawings and their meaning are listed in the list of reference numerals. Basically, the same parts are provided with the same reference numerals in the figures. The embodiment described is exemplary of the subject invention and has no limiting effect.

Ways to carry out the invention

FIG. 1 shows a rotationally symmetrical body 10, in the form of a closed on a first side 12 by means of a molded lid 14 hollow cylinder 16. The cover 14th on the first side 12 of the body 10 has a coupling unit 18 which extends substantially in the direction of the axis of rotation 19 of the rotationally symmetrical body 10. The coupling unit 18 is the first half of a quick coupling, which is designed in this example as a bayonet closure 20. The coupling unit 18 can be claimed to train. It is in the form of hollow cylindrical and hollow polygonal shapes of different diameters (compare sections A, B, C, ZA), which follow one another in such a way that a counter-shaped coupling device, which forms the second half of the quick coupling, axially into the hollow shape of the coupling unit 18 can be inserted and then locked by a turn. For the locking a recess 21 in the head portion A of the coupling unit 18 is provided, into which a corresponding locking pin of the inserted second half of the quick coupling can engage. Also on the first side 12 of the rotationally symmetrical body 10, at least one support area 22 is provided which, as in the lower half of the image Fig. 1 shown, three concentric with the axis of rotation 19 arranged bearing surfaces 24 which are inclined at an angle α of about 135 ° to the axis of rotation 19 and distributed uniformly over the circumference. The inclination angle α can be adjusted to the respective requirements in a range of 100 ° to 170 °. Particularly suitable angles have turned out α in the range of 120 ° to 150 ° us especially of 135 °. On a second side 26 of the rotationally symmetrical body 10, which is opposite to the first side 12, in the lower half of the image Fig. 1 embodiment shown axially spaced from the support portion 22, a centering portion 28 is provided, which has three concentric with the axis of rotation 19 arranged bearing surfaces 24 '; which are inclined against the first side 12 and against the axis of rotation 19. The inclination angle β is about 30 °. But it is also an inclination angle β in the range between 15 ° and 100 ° possible. In the example shown in the lower half of the figure, the bearing surfaces 24 'contact each other in the circumferential direction and form an annular surface. Instead of inclined bearing surfaces 24 ', in principle, convexly or concavely curved bearing surfaces 24' in the centering region 28 are also conceivable (not shown) against the first side 12 and the axis of rotation 19.

As in the upper half of the Fig. 1 can be provided on the first side 12 of the rotationally symmetrical body 10 instead of a plurality of bearing areas 22. The upper half of the picture Fig. 1 shows on the first side 12 of the rotationally symmetrical body 10, two bearing areas 22 with each of the first side 12 and against the rotation axis 19 convexly curved bearing surfaces 24, which are each formed in this example as a closed annular surfaces. The two annular bearing surfaces 24 are arranged both axially and radially spaced from one another by means of a shoulder incorporated in the end face of the cover 14. Of course, it is also conceivable instead of concave bearing surfaces 24 to provide convexly curved bearing surfaces (not shown). As the example shown in the upper half of the figure shows, the centering region 28 on the second side 26 of the rotationally symmetrical body 10 can also be omitted if, for example, it is not necessary for secure and central clamping with a low weight of the body 10 and a small axial extent. The in Fig. 1 shown body 10 is an example of a pipe section, in which the lid 14 is separated with the coupling unit 18 after the completed processing. Similarly configured body, in which the cover 14 with the coupling unit 18 either only partially or not separated, for example, can serve as housing parts.

Fig. 2 shows a rotationally symmetrical body 10 which is formed in the form of a rotor 30 with a hub 32 and molded onto the hub 32 blades 34. The hub 32 axially projects beyond the rotor blades 30 on the first side 12 of the rotor 30. The transition from an approximately cylindrical outer surface 36 of this protruding part of the hub 32 to its end face 38 is as a support region 22 with a convex against the first side 12 and the axis of rotation 19 inclined, annular bearing surface 24 designed. On the first side 12 of the rotor 30, a coupling unit 18 is provided in the hub 32. The coupling unit 18 is identical to that in FIG Fig. 1 shown bayonet lock 18/20. On the second side 26 of the rotor, a centering region 28 is provided, which projects axially beyond the rotor blades 34 toward the second side. The centering region 28 has bearing surfaces 24 ', which are inclined relative to the first side 12 and the axis of rotation 19 of the rotor 30.

The inclination angle β is about 20 ° in this example. The individual bearing surfaces 24 'are interconnected in the circumferential direction in this example and form an annular surface. The rotor 30 shown in this figure is a cast-in-one rotor 30 which has a cast-in mark 9 between two blades 34 on the hub 32, the always same orientation of the rotor 30 in space and thus always exactly the same clamping in an inventive Device allowed.

In FIG. 3 is shown as another example of a rotationally symmetrical body 10, another embodiment of a rotor 30 with hub 32 and blades 34. The rotor 30 is basically constructed like the one in FIG Fig. 2 , However, the centering region 28 on the second side of the rotor 30 in this case does not protrude axially beyond the rotor blades 34. Rather, the bearing surfaces 24 'of the centering region 28 are arranged in this case uniformly distributed over the circumference in a concentric ring between the blades 34. To better identify them, they are drawn with a greater line width. The bearing surfaces 24 'are concave in this case formed against the first side 12 of the rotor 30 and its axis of rotation 19. On the first side 12 of the rotor 30 is, as in the rotor in Fig. 2 , The transition from the approximately cylindrical outer surface 36 of the protruding part of the hub 32 to the end face 38 is designed as a support portion 22 with a convex against the first side 12 and the axis of rotation 19 inclined, annular support surface 24. In the hub 32, a coupling unit 18 is again provided on the first side 12 of the rotor 30. The coupling unit 18 shown in the upper half of the figure is again a half of a quick coupling, in particular a further embodiment of a bayonet closure 40 Fig. 3 shown one half of this quick coupling is in Fig. 4 in full diameter in section along the line IV-IV of the Fig. 3 shown. It has radially in the hollow cylinder of the coupling unit 18/40 projecting Kreissegmentflansche 42, which are spaced apart, evenly distributed over the circumference. As an anti-rotation 41, the Kreissegmentflansche 42 projections 43, each projecting axially into the hollow cylinder and on the lying in Urzeigerrichtung side each Kreissegmentflansches 42 are arranged. For locking a ramp-shaped recess 44 is provided in the coupling unit 18/40, which serves to receive a locking element of the coupling device to be inserted. A designed as a pin with opposite trained Kreissegmentflanschen coupling device which forms the second half of this quick coupling can be inserted with their flanges offset to the Kreissegmentflanschen 42 of the coupling unit 18/40 axially in the coupling unit 18/40 and then locked by a clockwise rotation. The Kreissegmentflansche the two halves of the quick coupling then engage behind each other, wherein the Kreissegmentflansche be brought into abutment with the trained as over-rotation 41 projections 43 and the locking element frictionally engages in the recess 44, which results in a non-positive securing against turning back and move a backup against axial , The projecting beyond the blades 34 part of the hub 32 can be separated if necessary after the completed processing.

In the lower half of the Fig. 3 is a further embodiment of a coupling unit 18 dargestelt that in Fig. 5 again in full diameter in section along the line VV the Fig. 3 is shown. This is a first half of a screw 46, which is designed as a hollow cylinder with internal thread 48, and can be connected to a counter-configured coupling device.

The 6 and 7 show a device according to the invention 50 for clamping rotationally symmetrical body 10 in a partial view in section along the axis of rotation 19 of the body 10 to be clamped. Fig. 6 shows the inventive device 50 without being clamped body 10, while Fig. 7 the rotationally symmetrical body Fig. 5 clamped in the device 50 shows.

The device 50 comprises a support element 52 with a hollow cylindrical wall 54 and a bottom 56 closing the hollow cylinder 54 on one side. The support element 52 has an axis 19 'which coincides with the axis of rotation 19 of the body 10 to be clamped. A to the axis 19 'concentric recess 58 in the bottom 56 is used for Receiving a stop 60. The stopper 60 is a solid cylinder and concentric with the axis 19 'has a through hole 62 in which a tie rod 64 is axially guided with radial play 66. The tie rod 64 has at its working end 61 a coupling device 63 which is connectable to the coupling unit 18 of the body to be clamped. The tie rod 64 as a whole, or only its coupling device 63, are designed to be interchangeable and adapted to the coupling unit of the body to be clamped. The tie rod 64 is rotatable about its axis 19 'and reciprocally movable in the axial direction. Via a controllable hydraulic or pneumatic (not shown), the tie rod 64 can be actuated and the tensile force F1 can be adjusted.

The fixed stop 60 has on its side facing away from the clamped body 10 a wide annular flange 68, whose diameter corresponds approximately to the diameter of the recess 58. It is fixed via this annular flange 68, for example by means of a press fit in the recess 58 of the support element 53. On its opposite side of the annular flange 68, the stopper 60 has a smaller diameter than the recess 58, so that an annular gap 70 between the bottom 56 of the support member 52 and the stopper 60 results. In this gap 70, a support member 72 is arranged, which is axially movable and resiliently supported on the annular flange 68 of the fixed stop 60. The spring force F2 of the resilient support 74 is aligned in the opposite direction to the pulling force F1. The support member 72 and the resilient support 74 are interchangeable and adapted to the body 10 to be clamped designed differently. The support member 72 has support surfaces 73 which are inclined against the axis 19 'and in this example contact each other in the circumferential direction and form an annular surface. As in Fig. 7 the support surfaces 73 of the support element 72 cooperate with the support surfaces 24 of the support region 22 on the first side 12 of the rotationally symmetrical body 10. The resilient support 74 of the support member 72 is designed so that when tightening a rotationally symmetrical body 10 by means of the tie rod 64 against the support member 72, the support element 72 initially backwards in the axial direction until either using a mechanical spring 75, as they is shown in this example, this is very tense, ie, for example, completely compressed, or the spring force F2 and the tensile force F1 are in equilibrium (the latter with mechanical springs or hydraulically controlled suspension possible). For clamped rotationally symmetric body 10 with low axial extent and a low weight can be achieved so a very accurate and secure centric clamping.

For larger bodies 10 with higher weight, it is convenient to work with a centering device 76. Like support member 72 and tie rod 64 and coupling device 63 of the tie rod 64 also interchangeable and differently designed centering devices 76 are provided. Examples are in the 8 and 9 shown. The centering device 76 is formed substantially disc-shaped with a central opening 80. Concentrically around the opening 80 centering surfaces 82 are provided, which in the in the Fig. 6 to 8 shown examples are inclined against the axis 19. The centering surfaces 82 are adapted to the body to be clamped designed and distributed so that they can cooperate with the bearing surfaces 24 'of the centering region 28 of the body 10 to be clamped. For this purpose, the centering surfaces 82 can protrude like a finger into the central opening 80 of the disc-shaped centering device 76, as shown in FIG Fig. 8 is shown. Such a configuration is useful if the body 10 to be clamped is, for example, a rotor 30 and the bearing surfaces 24 'are arranged between the rotor blades 34, as in the case of FIG Fig. 3 In other cases, it may be useful to use a centering device 76, the centering surfaces 82 touching each other in the circumferential direction, thus forming an annular centering surface, as shown in FIG Fig. 9 is shown. To save material, and / or if this is desirable, for example with respect to the vibration stiffness, the centering device 76 may have recesses 84, as in the upper half of the Fig. 9 is shown or it can be used a full annular disc, as shown in the lower half of the Fig. 9 is shown. There are any further embodiments for the centering disk 76. Thus, the centering surfaces 82 may be arranged on circles of different diameters or multiple disks may be used come, in which the centering surfaces 82 axially spaced from each other and optionally arranged on different Kreisdurchmessem.

In order to exchange the centering discs 76, 52 threaded openings 86 are provided on the end face 78 of the cylindrical wall 54 of the support member. The centering device 76 have openings 90 which can be brought into coincidence with the threaded openings 86. By means of screws which are inserted through the openings 90 of the centering devices 76 and screwed into the threaded openings of the wall 54, the centering devices on the support element 52 are releasably fixed.

In order to clamp rotationally symmetrical body 10 different axial length, it is conceivable that the cylinder wall 54 is designed to be adjustable in length or the centering instead of the support member may be fixed to a separate carrier which is displaceable in the axial direction. Also with respect to the stop 60 modifications are conceivable. Thus, the stopper 60 may be e.g. also be integrally formed with the support member 52. Or it can be provided as an exchangeable element, whose the body 10 to be clamped facing side adapted adapted to the respective requirements. Instead of a press fit, the fixation must then be made using other suitable means, such as screws or clamping connections.

If now a rotationally symmetrical body 10 which is not configured according to the invention is clamped in a device 50 according to the invention, then the tension rod 64 is moved axially through the passage opening 62 of the stop 60 towards the rotationally symmetrical body 10. The coupling device 63 of the tie rod 64 is inserted into the coupling unit 18 of the rotationally symmetrical body 10 and the tie rod 64 is rotated, so that the tie rod 64 by means of the coupling device 18 but releasably connected to the rotationally symmetrical body 10 is connected. The tie rod 64 is axially withdrawn through the through hole 62 and brought the bearing surfaces 24 of the support portion 22 with the support surfaces 73 of the support member 72 in contact. When using a centering device 76 at about this time should also the bearing surfaces 24 'of the centering region 28 of the rotationally symmetrical body 10 come into contact with the centering surfaces 82 of the centering device 76. Upon further tightening, the support member 72 axially yields a little until the spring force F2 and the tensile force F1 are in equilibrium or the spring 75 is compressed accordingly and the support member 72 is fully supported on the annular flange 68 of the stopper 60. Due to the special design of the support surfaces 73, centering surfaces 82 and bearing surfaces 24, 24 '- curved or inclined -, the rotationally symmetrical body 10 aligns itself when tightening against the support surfaces 73 and support and centering 73, 82 of coaxial centric. The resiliently yielding support element 72 supports this. Due to the axial guidance of the tie rod 64 with radial play 66 a misjudged can be avoided. If the body 10 to be clamped has a marking 9 which allows it to be clamped in the device 50 with exactly the same spatial orientation, an exact, centric clamping is possible even in the case of any necessary re-clamping. If the marking 9 is already introduced into the cast body in the case of a cast body, unwanted unbalance effects, as can occur with subsequently mechanically introduced markings, can be avoided. It goes without saying that cast-in markings should be installed so that they are as visible as possible even on the clamped body and in use of the finished body, this does not affect its function.

LIST OF REFERENCE NUMBERS

10

rotationally symmetrical body

12

first page

14

cover

16

hollow cylinder

18

clutch unit

19, 19 '

axis of rotation

20

bayonet catch

22

support area

24, 24 '

bearing surface

26

second page

28

centering

30

rotor

32

hub

34

blade

36

cylindrical outer surface

38

front

40

bayonet catch

41

Overspeed protection

42

Kreissegmentflansch

43

head Start

44

ramp-shaped recess

46

screw

48

inner thread

50

Device according to the invention

52

supporting member

54

Hollow cylinder wall

56

ground

58

recess

60

attack

61

Working tie-rod

62

Through opening

63

coupling device

64

tie rods

66

radial play

68

annular flange

70

gap

72

support element

73

support surfaces

74

resilient support

75

feather

76

centering

78

front

80

central opening

82

centering

84

recess

86

threaded opening

90

opening

Claims (11)

1. Method of clamping a rotationally symmetrical body for the purpose of machining, in which method the body (10), with its first side (12), is pulled by means of a tensile force (F1), which acts in extension of the rotation axis (19, 19') of the body (10) on the first side (12) of the body (10), against a supporting element (72) having a centering effect, characterized in that the supporting element (72) is acted upon with a spring force (F2) which is opposed to the tensile force (F1), the spring force (F2) is slightly smaller than the tensile force (F1) and is proportioned in such a way that, when the body (10) strikes the supporting element (72), the supporting element (72) first of all yields in the axial direction.
2. Method according to Claim 1, characterized in that the tensile force (F1) is transmitted to the body (10) by means of a tie rod (64), which is preferably connected to the body (10) by means of a quick-action coupling (20, 40, 46).
3. Method according to Claim 2, characterized in that the tie rod (64) is guided with radial clearance (66) axially and concentrically to the rotation axis (19, 19') of the rotationally symmetrical body (10).
4. Method according to one of Claims 1 to 3, characterized in that the body (10), with a centering region (28) which is arranged at an axial distance from the first side (12) of the body (10) and is oriented in the same direction as the first side (12), is pulled against a centering device (76).
5. Method according to Claim 1, characterized in that spring force (F2), tensile force (F1) and configuration of supporting element (72) are selected in accordance with the body (10) to be clamped.
6. Method according to Claim 1, characterized in that, when a rotor (30) is clamped as a rotationally symmetrical body (10) which preferably has integrally formed moving blades (34), a centering device (76) is selected which has centering surfaces (82) engaging between the moving blades (34) in a finger-like manner.
7. Device for clamping a rotationally symmetrical body (10) for the purpose of machining, having a tie rod (64) which is mounted in the device (50) in such a way that it can act on the body (10), to be clamped, axially and concentrically to the rotation axis (19, 19') of the latter and is axially guided with radial clearance (66) for the axial pulling movement, the tensile force (F1) of the tie rod (64) preferably being adjustable, and having a supporting element (72), against which the rotationally symmetrical body (10) to be clamped can be pulled by means of the tie rod (64), characterized in that the supporting element (72) is supported in a spring-loaded manner on a stop (60) of the device (50) in such a way that it is movable in the axial direction (19, 19') of the body (10) to be clamped, the spring force (F2) counteracting the tensile force (F1) and preferably being adjustable.
8. Device according to Claim 7, characterized in that the tie rod (64) is provided with a coupling device (63) which can be connected to a coupling unit (18) of the body (10) to be clamped and is preferably designed as the one half of a quick-action coupling (20, 40, 46) .
9. Device according to either of Claims 7 or 8, characterized in that the supporting element (72) is provided with supporting surfaces (73) which are arranged concentrically to the rotation axis (19, 19') of the body (10) to be clamped and which are preferably inclined toward the rotation axis (19, 19') and/or are contiguous along a defined circumference and form an annular supporting surface.
10. Device according to one of Claims 7 to 9, characterized in that a centering device (76) is provided at an axial distance from the supporting element (72), this centering device (76) being provided with centering surfaces (82) which are arranged concentrically to the rotation axis (19, 19') of the body (10) to be clamped and are preferably inclined toward the rotation axis (19, 19').
11. Device according to Claim 10, characterized in that the centering surfaces (82) are distributed uniformly over the circumference and extend in a finger-like manner toward the rotation axis (19, 19') from a defined outer circumference up to a defined inner circumference and/or are contiguous in particular along a defined circumference and form an annular centering surface.

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