CH701326A1 - Swivelable apparatus for e.g. four-axis machine tool, for processing work-piece, has bearing units designed such that rotation center is excentric to centre of bearing pin and/or bearing borehole - Google Patents

Abstract

The apparatus has a swivelable bridge (2) for supporting a work-piece. The swivelable bridge is supported around a swiveling axis (A) in a machine frame (11) and a bearing case (4) in a swivelable manner via two bearing units, which include a spherical bearing and an excentric bushes. Each bearing unit supports a bearing pin in a bearing borehole. The bearing units are designed such that a rotation center is excentric to a centre of the bearing pin and/or bearing borehole. The swivelable bridge comprises a clamping surface (9), which is arranged between the bearing units. Independent claims are also included for the following: (1) a method for manufacturing the swivelable apparatus (2) a method for manufacturing the machine tool (3) a method for operating the machine tool.

Description

The present invention relates to a pivoting apparatus for a machine tool, a machine tool with the pivoting apparatus, a method for producing the pivoting apparatus and method for producing and operating the machine tool according to the preambles of the independent claims.

Swiveling devices for machine tool machines are used wherever more than the usual three axes are required for the machining of a workpiece or to avoid unnecessary transfer work to "envelope", i. E. a contour is created by machining two opposite sides.

In particular, in the latter case, it is of crucial importance that the pivot axis, the pivoting apparatus coincides exactly with the coordinate system of the machine tool, i. is aligned exactly parallel to one of the three main axes (X, Y and Z axes) of the machine tool, as in this processing add any deviations and lead to an offset between the processing paths. Correspondingly high are the demands on the precision of such processing machines with pivoting devices, which often makes a selection pairing of the finished components or extremely complex manufacturing processes necessary. Both leads to relatively high production costs. Also, the known machine tools with pivoting apparatus have the disadvantage that over time or by elastic deformation of the pivoting bridge, e.g. For particularly heavy workpieces, occurring position deviation can not be corrected, with the result that in these cases, cuts in the machining precision must be made.

It therefore has as its object to provide a pivoting apparatus and a machine tool with a pivoting apparatus and manufacturing and operating method for these available, which do not have the disadvantages of the prior art mentioned above or at least partially avoided.

This object is achieved by the pivoting apparatus, the machine tool and the manufacturing and operating methods according to the independent claims.

Accordingly, a first aspect of the invention relates to a pivoting apparatus for a machine tool, comprising a pivoting bridge for supporting a workpiece to be machined and optionally further aids for the attachment and positioning of the workpiece to be machined, such. Clamping and Indexiervorrichtungen, when used as intended the swivel apparatus on a machine tool. The pivoting bridge is pivotally mounted by means of two bearing units about a pivot axis in or on a support structure, wherein the bearing units are spaced apart along the pivot axis. Preferably, the bearing units are arranged at both ends of the pivot bridge, so that the area of the pivot bridge, which is provided for receiving the workpiece, along the pivot axis seen between the two bearing units is arranged. Each storage unit serves to support a journal in a bearing bore. The actual bearing of the respective bearing unit can be designed both as a sliding bearing and as a roller bearing and the bearing pin can be formed both from the pivot bridge and from the support structure. In this case, at least one of the two bearing units is designed such that its center of rotation is eccentric to the center of the journal and / or to the center of the bearing bore. This can e.g. be achieved that sliding or rolling bearings with respect to their rotation center eccentric receiving holes and / or outer circumferences (claims eccentric bearings) are used or sliding or rolling bearing with respect to their center of rotation concentric receiving holes or outer circumferences in combination with eccentric bushes.

By a specific choice of eccentricity, it is possible to correct production-related positional deviations of the journal and / or the bearing bore, so that the use of cost, generously tolerated components is possible, and depending on the design and a correction of wear or deformation positional deviations.

In a preferred embodiment of the pivoting apparatus, both bearing units are structurally designed such that their center of rotation is in each case eccentric to the center of the respective journal and / or the respective bearing bore. This makes it possible to correct a position deviation in both bearings.

In yet a preferred embodiment of the pivoting apparatus is at least one of the bearing units a bearing, preferably a rolling bearing, provided which is arranged with an eccentric bushing on the bearing journal and / or in the bearing bore. In this way it is possible to use inexpensive commercially available concentric bearings and to correct a production-related deviation of the center of the journal and / or the bearing bore by selecting eccentric bushings with appropriate eccentricity in a simple and cost-effective manner and also by turning the eccentric bushings on the journal and / or to perform fine corrections or post-corrections in the bearing bore.

Preferably, in each case exactly one eccentric bush is used on the bearing journal and / or in the bearing bore. This results in the advantage of a particularly simple, inexpensive construction.

In the event that on the journal and / or in the bearing bore two bearing bushes are arranged with the same axial orientation into each other, which preferably takes place under direct adjacency of the eccentric bushings together, there is the advantage that both the size of Eccentricity by rotation of the eccentric bushes relative to each other and the position of the eccentricity can be adjusted by common rotation of the eccentric bushes relative to the bearing pin and the bearing bore in wide ranges.

If eccentric bushings are present both on the bearing journal and in the bearing bore of the bearing, manufacturing deviations of both the pivoting bridge and the supporting structure can be corrected independently of each other.

The circumferential positions of the eccentric bushings on the bearing journals and / or in the bearing bores are preferably fixed by positive engagement with the respective bearing journal or the respective bearing bore, so that the position and / or magnitude of the eccentricity is not inadvertently caused by twisting of the eccentric bushings, e.g. when pivoting the swing bridge, can change. This can e.g. positively effected by a radial positioning pin or a positioning screw or non-positively by clamping.

In a preferred embodiment, it is provided that the circumferential position of at least one of the eccentric bushes is adjustable relative to the Lagerzapfer or the bearing bore on which or in which these, in particular by means of an electric actuator. For this, e.g. the eccentric bushing be formed on its outer circumference as a worm wheel, in which meshes the worm of a servomotor. This makes it possible to manually or automatically correct any deviations in position due to wear or deformation, e.g. during machine maintenance or during operation.

In yet another preferred embodiment of the inventive swivel apparatus, the bearing units rolling bearings, preferably ball bearings, which are preferably biased. Such bearings are inexpensive commercially available and also free of play in the case of preloaded bearings.

In yet another preferred embodiment, the pivoting bridge of the pivoting apparatus on a clamping surface.

This is advantageously seen in the axial direction, i. seen in the direction of the pivot axis of the pivot bridge, between the two bearing units. As a result, particularly stiff swivel bridge constructions are possible.

Preferably, the pivot bridge is designed such that the clamping surface, when it is facing upwards and extending in a horizontal plane, is arranged below the pivot axis of the pivot bridge. This has the advantage that, when the swivel apparatus is used as intended, the pivot axis can run through the workpiece, which saves space and allows the travel paths of the machining tool to be minimized.

A second aspect of the invention relates to a method for producing the pivoting apparatus according to the first aspect of the invention.

In this case, in a first step, the pivot bridge is provided with finished bearing journal or finished bearing bores and with a preferably processed reference surface and then by measuring the deviation of the position of the axis defined by the centers of the bearing bores or bearing pin axis of a target Determined position with respect to the reference surface. As a reference surface is preferably a finished machined clamping surface of the swing bridge.

If the deviation from the desired position known, eccentric bearings and / or eccentric bushes are selected for concentric bearing in a next step in response to this deviation. The eccentric bearings and the eccentric bushes are selected with respect to their eccentricity that at a proper storage of the swivel bridge in the support structure with the selected eccentric bearings and / or with the selected eccentric bushes in combination with concentric bearings the determined deviation from the target Location can be reduced or canceled by their eccentricity.

Then, the bearing of the swivel bridge with the selected eccentric bearings and / or with the selected eccentric bushes and associated concentric bearings such in the support structure that the deviation of the position defined by the centers of the bearing bores or journals of the pivot bridge axis of the Target position is reduced or canceled by the eccentricity of the eccentric bearing or the eccentric bushes.

By the inventive method, it is possible to produce a high-precision swivel apparatus with little labor cost from relatively respect to the machining tolerances relatively generously tolerated components.

A third aspect of the invention relates to a machine tool with a pivoting apparatus according to the first aspect of the invention or with a pivoting apparatus produced by the method according to the second aspect of the invention.

A fourth aspect of the invention relates to a method for manufacturing the machine tool according to the third aspect of the invention.

In this case, in a first step, the pivoting bridge is mounted with the support structure in the intended position on a machine tool to be equipped therewith, wherein the pivot bridge is stored with concentric bearings or bearing units such or in the support structure that the centers of rotation of the bearing or bearing units are concentric with the centers of bearing trunnions and bearing bores.

Then, in a second step, a deviation of the pivot axis of the so-mounted pivot bridge of a desired position with respect to the machine tool, in particular from the coordinate system of the machine tool, which by the three major axes (X, Y and Z axes) given the same is determined. Since the pivot axis of the pivoting bridge is usually to be aligned exactly parallel to one of the three main axes of the machine tool, the deviation of the pivot axis from an exact parallelism to one of the three main axes of the machine tool is usually determined as a deviation from a desired position or from the coordinate system of the machine tool ,

After this deviation is known, in a third step, depending on the deviation, eccentric bearings and / or eccentric bushes for concentric bearings are selected. In this case, the eccentric bearing or the eccentric bushings are selected with respect to their eccentricity that at a proper storage of the pivoting bridge in or on the support structure with the selected eccentric bearings and / or with the selected eccentric bushes in combination with concentric bearings, the determined deviation from the desired position or the coordinate system of the machine tool can be reduced or canceled by their eccentricity.

In a fourth step, then the new bearing of the pivoting bridge in the support structure using the selected eccentric bearings and / or the selected eccentric bushes in combination with concentric bearings is carried out such that the deviation is reduced or canceled by the eccentricity of the same.

A fifth aspect of the invention relates to another method for manufacturing a machine tool according to the third aspect of the invention.

In this case, after carrying out the manufacturing process according to the second aspect of the invention in a first step, the pivoting apparatus resulting from this method is mounted in the proper position on the machine tool to be equipped with the pivoting apparatus.

Then, in a second step, a deviation of the pivot axis of the pivot bridge of a desired position with respect to the machine tool or from the coordinate system of the machine tool, which is given by the three major axes (X, Y and Z axes) determined. Since the pivot axis of the pivoting bridge is usually to be aligned exactly parallel to one of the three main axes of the machine tool, the deviation of the pivot axis from an exact parallelism to one of the three main axes of the machine tool is usually determined as a deviation from a desired position or from the coordinate system of the machine tool ,

Subsequently, in a third step, depending on the determined deviation, eccentric bearings and / or eccentric bushings are selected for concentric bearings. In this case, the eccentric bearing or the eccentric bushings are selected with respect to their eccentricity that at a proper storage of the pivoting bridge in or on the support structure with the selected eccentric bearings and / or with the eccentric bushes in combination with concentric bearings, the determined deviation of the pivot axis the eccentricity of the bearings or bearing units and / or the eccentric bushes can be reduced or eliminated.

Thereafter, the new bearing of the pivoting bridge takes place in or on the support structure using the selected eccentric bearings and / or the selected eccentric bushes in combination with concentric bearings such that the deviation of the pivot axis is reduced or canceled by their eccentricity.

By the inventive method according to the fourth and fifth aspect of the invention, it is possible to produce high-precision 4- or 5-axis machine tools relatively inexpensively.

A sixth aspect of the invention relates to a method for operating the machine tool according to the third aspect of the invention, wherein the machine tool is equipped with a pivoting apparatus according to the invention, wherein at least one of the bearing units comprises an eccentric bushing arranged on the bearing journal or in the bearing bore and which is also designed such that the circumferential position of the eccentric bush is adjustable relative to the Lagerzapfer or the bearing bore on which or in which it is arranged.

In this case, a workpiece is clamped on the pivot bridge of the pivoting apparatus in a first step.

Then, a deviation of the position of a surface of the clamped workpiece and / or a surface of the clamping workpiece carrying the pivoting bridge relative to a desired position is determined.

Subsequently, depending on the determined deviation, the circumferential position of the eccentric bushing relative to the bearing journal or the bearing bore, on which or in which it is arranged, changed, such that the determined deviation is reduced or canceled.

In this case, in particular if the change in the circumferential position of the eccentric bushing takes place by means of an electric actuator, individual or all steps can be carried out automatically, e.g. by the control of the machine tool or a higher-level control.

By the method according to the invention it is possible to correct any positioning errors of the workpiece to be machined and any deviations caused by wear and / or deformation. This can be done for machining series or individually for each machining run.

Further preferred embodiments of the invention will become apparent from the dependent claims and from the following description with reference to the figures. Showing: <Tb> FIG. 1 <sep> a perspective top view of the processing zone of a machine tool according to the invention with a swivel apparatus according to the invention; and FIGS. 2 to 5 each show a vertical section through the right-hand bearing arrangement of the swivel apparatus of the machine tool from FIG. 1 along the line C-C in FIG. 1 in various preferred embodiments of the swivel apparatus.

The basic structure of a machine tool 1 according to the invention with swiveling apparatus 2, 3, 4, 11 is apparent from FIG. 1, which shows a perspective top view obliquely from above onto the processing zone of such a machine 1. As can be seen, the processing machine 1 has a machine spindle 10 which is movable along its three main axes X, Y, Z (coordinate system of the processing machine) and which serves to receive and drive the processing tool (not shown). Below the machine spindle 10 is the pivot bridge 2 for supporting the workpiece to be machined (not shown), which is fixed end with two bearing assemblies 14 pivotally about a pivot axis A on the machine frame 11. In the present case, the pivot axis A is aligned parallel to the X axis of the coordinate system of the machine tool 1, but it is also quite possible in embodiments that it is aligned parallel to the Y or Z axis.

The swivel bridge 2 can be pivoted starting from the illustrated basic position by means of a motor 12 in both directions about the pivot axis A. Arranged in the axial direction between the bearing assemblies 14, the pivoting bridge 2 has a clamping surface 9 for supporting the workpiece to be machined, which here carries a jig 13 for the workpiece. The workpiece holder of the jig 13 is rotatable about a pivot axis A of the pivot bridge 2 perpendicular axis B. In the illustrated basic position, the clamping surface 9 extends in a horizontal plane below the pivot axis A.

As can be seen in conjunction with FIG. 2, which shows a vertical section along the line CC in FIG. 1 through the right-hand bearing arrangement 14 of the swivel apparatus in a first preferred embodiment, the swivel bridge 2 is here in a bearing block 4 by means of a preloaded ball bearing 3 stored, which is connected to the machine frame 11 of the machine tool 1.

The ball bearing 3 is seated on a bearing pin 5 formed by the pivot bridge 2 and is mounted by means of an eccentric bushing 8a in a bearing bore 6 in the bearing block 4. The eccentric bushing 8a is chosen with respect to its eccentricity and arranged with respect to their circumferential orientation such in the bearing bore 6, that caused by manufacturing or assembly inaccuracies deviation of the position of the center of the bearing bore 6 is corrected by a desired position, ie at least reduced and is lifted at best. The eccentric bush 8a is secured against twisting in the bearing bore 6 by a locking pin (not shown).

Fig. 3 shows a vertical section along the line C-C in Fig. 1 through the right bearing assembly 14 in a second preferred embodiment of the pivoting apparatus. Again, the swing bridge 2 is mounted by means of a preloaded ball bearing 3 in the bearing block 4. However, the ball bearing 3 is arranged by means of an eccentric bush 8b on the bearing pin 5 formed by the pivot bridge 2, while it is mounted with its outer ring directly in the bearing bore 6 in the bearing block 4. Here, the eccentric bushing 8b is selected with respect to its eccentricity and arranged with respect to their circumferential orientation such on the bearing pin 5 that a conditional deviation due to manufacturing inaccuracies of the position of the center of the bearing pin 5 is corrected by a desired position. Again, the eccentric bush 8b is secured against rotation on the bearing pin 5 positively by securing means, not shown.

Fig. 4 shows a vertical section along the line C-C in Fig. 1 through the right bearing assembly 14 in a third preferred embodiment, which represents a combination of the first embodiment of FIG. 2 and the second embodiment of FIG. The ball bearing 3 is arranged here by means of a first eccentric bushing 8b on the bearing journal 5 formed by the pivoting bridge 2 and mounted in the bearing bore 6 in the bearing block 4 by means of a second eccentric bushing 8a. The eccentricities and orientations of the eccentric bushings 8a, 8b are selected such that deviations of the positions of the center of the bearing journal 5 and of the center of the bearing bore 6 caused by manufacturing and assembly inaccuracies are corrected by a desired position. Again, the eccentric bushes 8a, 8b secured against rotation.

Fig. 5 shows a vertical section along the line C-C in Fig. 1 through the right bearing assembly 14 in a fourth preferred embodiment, which is a further development of the second embodiment of FIG. 3. In this embodiment variant, the ball bearing 3 is arranged with two eccentric bushes 8b, 8c, arranged in the same axial orientation, on the bearing journal 5 of the pivoting bridge 2. Here, the eccentricities of the bearing bushes 8b, 8c and their circumferential alignment both relative to each other and with respect to the bearing pin 5 selected such that a conditional by manufacturing inaccuracies of the position of the center of the bearing pin 5 is corrected by a desired position. The eccentric bushes 8b, 8c are secured both against rotation relative to one another and against rotation on the bearing journal 5.

The left bearing assembly 14 may be carried out identically in each case in the previously described embodiments as the associated in Figs. 2 to 5 in section shown right bearing assembly 14. However, it may also be deviating from this formed. So it can be e.g. be useful for design and assembly considerations, the swing bridge 2 not with two end bearing pin 5 form, but with a bearing pin 5 and a bearing bore or with two positional holes.

Although only deep groove ball bearings 3 are used in the present examples, it is also provided to use other types of bearings or plain bearings.

In general, it should be noted that in FIGS. 2 to 5, the eccentricity of the eccentric bushes 8a, 8b, 8c has been exaggerated for better recognizability. In practice, this is in simple eccentric bushes in the range of manufacturing inaccuracies to be corrected, i. in the range of tenths or hundredths of millimeters. In the case of two eccentric bushings 8b, 8c arranged in the same axial orientation, larger individual eccentricities per eccentric bushing 8b, 8c can also be used, since these complement each other depending on the circumferential orientation of the eccentric bushings 8b, 8c or cancel each other out at least partially.

While preferred embodiments of the invention are described in the present application, it is to be understood that the invention is not limited to these and may be practiced otherwise within the scope of the following claims. In addition, the illustrated storage variants can also be combined with each other, as long as a combination from a technical point of view does not oppose or is not impossible.

Claims (14)

1. A swivel apparatus for a machine tool (1), comprising a pivoting bridge (2) for supporting a workpiece to be machined, which is secured by means of two axially spaced bearing units (3, 8a; 3, 8b; 3, 8a, 8b; 3, 8b, 8c) pivotally mounted about a pivot axis (A) in a support structure (4, 11), each bearing unit rotatably supporting a journal (5) in a bearing bore (6), characterized in that at least one of the bearing units (3, 8a; 8b; 3, 8a, 8b; 3, 8b, 8c) is designed such that its center of rotation is eccentric to the center of the bearing journal (5) and / or the bearing bore (6). 2. Swivel apparatus according to claim 1, characterized in that both bearing units (3, 8a; 3, 8b; 3, 8a, 8b; 3, 8b, 8c) are designed such that their center of rotation is eccentric to the center of the respective journal (5) and / or the respective bearing bore (6). 3. Swiveling apparatus according to one of the preceding claims, characterized in that at least one of the bearing units (3, 8a; 3, 8b; 3, 8a, 8b; 3, 8b, 8c) has a bearing (3) which is connected to an eccentric bushing (3). 8b, 8c) is mounted on the bearing journal (5) and / or with an eccentric bushing (8b, 8c) in the bearing bore (6). 4. pivoting apparatus according to claim 3, characterized in that the bearing (3) with exactly one eccentric bushing (8b) on the bearing journal (5) and / or with exactly one eccentric bushing (8a) in the bearing bore (6) is mounted. 5. swivel apparatus according to one of claims 3 to 4, characterized in that the bearing (3) with two mutually with the same axial orientation arranged eccentric bushings (8 b, 8 c) on the bearing journal (5) and / or in the bearing bore (6) is. 6. pivoting apparatus according to one of claims 3 to 5, characterized in that the pivoting apparatus is designed such that the circumferential position of at least one of the eccentric bushings (8 a, 8 b, 8 c) relative to the Lagerzapfer (5) or the bearing bore (6) on which or in which this eccentric bushing (8a, 8b, 8c) is arranged, is adjustable, in particular by means of an electric actuator. 7. pivoting apparatus according to one of the preceding claims, characterized in that the at least one bearing unit (3, 8a; 3, 8b; 3, 8a, 8b; 3, 8b, 8c) in particular comprises preloaded roller bearings, in particular preloaded ball bearings (3). 8. pivoting apparatus according to one of the preceding claims, characterized in that the pivoting bridge (2) has a clamping surface (9) which in the axial direction between the two bearing units (3, 8a; 3, 8b; 3, 8a, 8b; 8b, 8c) is arranged. 9. pivoting apparatus according to one of the preceding claims, characterized in that the pivoting bridge (2) has a clamping surface (9) which is arranged in a horizontal plane below the pivot axis (A) of the pivoting bridge (2). 10. A method for producing the pivoting apparatus according to one of the preceding claims, comprising the steps: a) providing the pivoting bridge (2) with finished bearing pin (5) and / or finished bearing bores and with a particular processed reference surface, in particular clamping surface (9); b) determining a deviation of the position of the axis defined by the centers of the bearing bores and / or bearing journals (5) of the pivoting bridge (2) from a desired position with respect to the reference surface (9); c) selecting, depending on the determined deviation from the desired position, at least one eccentric bearing and / or at least one eccentric bushing (8a, 8b, 8c) with a desired eccentricity, such that when the pivot bridge (2) is stored as intended in the support structure (4, 11) with the at least one eccentric bearing and / or with the at least one eccentric bushing (8a, 8b, 8c) in combination with a concentric bearing (3) the determined deviation from the desired position by the eccentricity of the at least one eccentric bearing and / or the at least one eccentric bushing (8a, 8b, 8c) can be reduced or canceled. d) supporting the pivoting bridge (2) with the selected at least one eccentric bearing and / or with the selected at least one eccentric bushing (8a, 8b, 8c) in combination with a concentric bearing (3) in the supporting structure (4, 11), that the deviation of the position of the axis defined by the centers of the bearing bores and / or bearing journals (5) of the pivoting bridge (2) from the desired position by the eccentricity of the at least one bearing and / or the at least one eccentric bushing (8a, 8b, 8c ) is reduced or canceled. 11. Machine tool (1) with a pivoting apparatus according to one of the preceding claims. 12. A method for producing the machine tool (1) according to claim 10, comprising the steps: a) mounting the pivoting bridge (2) with the supporting structure (4, 11) in the intended position on the machine tool (1), wherein the pivoting bridge (2) with bearing units (3, 8a; 3, 8b; 3, 8a, 8b; 3, 8b, 8c) is supported in or on the supporting structure (4, 11) such that the centers of rotation of the bearing units (3, 8a; 3, 8b; 3, 8a, 8b; 3, 8b, 8c) are concentric with the centers the respective bearing pin (5) and bearing bores (6) are; b) determining a deviation of the pivot axis (A) of the pivoting bridge (2) so mounted from a desired position, in particular from the coordinate system (X, Y, Z) of the machine tool (1); c) selecting, depending on the determined deviation, at least one eccentric bearing with a desired eccentricity and / or at least one eccentric bushing (8a, 8b, 8c) with a desired eccentricity, such that when the pivoting bridge (2) is supported in the Support structure (4, 11) using the at least one selected eccentric bearing and / or the at least one selected eccentric bushing (8a, 8b, 8c) in combination with a concentric bearing (3) the deviation by the eccentricity of the at least one bearing and / or the at least one eccentric bushing (8a, 8b, 8c) can be reduced or canceled; and d) relocation of the pivoting bridge (2) in the support structure (4, 11) using the selected at least one eccentric bearing and / or the selected at least one eccentric bushing (8a, 8b, 8c) in combination with a concentric bearing (3) that the deviation is reduced or eliminated by the eccentricity of the at least one bearing and / or the at least one eccentric bushing (8a, 8b, 8c). 13. A method for producing the machine tool (1) according to claim 10, comprising the steps: a) providing the pivoting bridge (2) with a reference surface, in particular machined clamping surface (9), and finished bearing pin (5) and / or finished bearing bores; b) determining a deviation of the position of the axis defined by the centers of the bearing bores and / or bearing journals (5) of the pivoting bridge (2) from a desired position with respect to the reference surface (9); c) selecting, depending on the determined deviation, at least one eccentric bearing with a desired eccentricity and / or at least one eccentric bushing (8a, 8b, 8c) with a desired eccentricity such that when the pivoting bridge (2) is mounted according to the intended purpose at least one eccentric bearing and / or with the at least one eccentric bushing (8a, 8b, 8c) in combination with a concentric bearing (3) in the support structure (4, 11) the determined deviation of the position of the through the centers of the bearing bores and / or Bearing (5) of the pivoting bridge (2) defined axis by the eccentricity of the at least one bearing and / or the at least one eccentric bushing (8a, 8b, 8c) can be reduced or canceled. d) mounting the swivel bridge (2) with the support structure (4, 11) in the intended position on the machine tool (1), wherein the swivel bridge (2) with the selected at least one eccentric bearing and / or with the selected at least one eccentric bushing (2). 8a, 8b, 8c) in combination with a concentric bearing (3) is mounted in or on the support structure (4, 11) such that the deviation of the position of the through the centers of the bearing bores and / or journals (5) of the pivot bridge ( 2) defined axis by the eccentricity of the at least one eccentric bearing and / or the at least one eccentric bushing (8a, 8b, 8c) is reduced or canceled; e) determining a deviation of the pivot axis (A) of the so mounted pivoting bridge (2) of a desired position, in particular of the coordinate system (X, Y, Z) of the machine tool (1); f) selecting, depending on the determined deviation, at least one eccentric bearing with a desired eccentricity and / or at least one eccentric bushing (8a, 8b, 8c) with a desired eccentricity such that when the pivoting bridge (2) is mounted according to the intended purpose at least one eccentric bearing and / or with the at least one eccentric bush (8a, 8b, 8c) in combination with a concentric bearing (3) in the support structure (4, 11) the determined deviation of the pivot axis (A) by the eccentricity of the at least one eccentric bearing and / or the at least one eccentric bushing (8a, 8b, 8c) can be reduced or canceled; and g) relocation of the pivoting bridge (2) in or on the support structure (4, 11) using the selected at least one eccentric bearing and / or the selected at least one eccentric bushing (8a, 8b, 8c) in combination with a concentric bearing (3) such that the deviation of the pivot axis (A) by the eccentricity of the at least one bearing and / or the at least one eccentric bushing (8a, 8b, 8c) is reduced or canceled. 14. A method for operating a machine tool (1) according to claim 10 with a pivoting apparatus according to claim 6, comprising the steps: a) clamping a workpiece on the pivot bridge (2) of the pivoting apparatus; b) determining a deviation of the position of a surface of the clamped workpiece and / or a surface (9) of the clamping bridge carrying the clamped workpiece (2) with respect to a desired position; and c) variation, depending on the determined deviation, of the circumferential position of at least one of the eccentric bushes (8a, 8b, 8c) relative to the bearing journal (5) or the bearing bore (6) on which or in which it is arranged such that the deviation is reduced or canceled.