WO2016151043A1

WO2016151043A1 - Machine tool comprising at least two planar motors

Info

Publication number: WO2016151043A1
Application number: PCT/EP2016/056444
Authority: WO
Inventors: Sascha Jaumann; Wolfgang RÖMPP
Original assignee: Mauser-Werke Oberndorf Maschinenbau Gmbh
Priority date: 2015-03-24
Filing date: 2016-03-23
Publication date: 2016-09-29
Also published as: DE102015104443A1; EP3274126A1; CN107427979A

Abstract

Disclosed is a machine tool in which a carriage is guided and driven using a two-dimensional guide and a planar motor. It is possible to use two planar motors, each of which is movable along two axes such that a rotational degree of freedom can be corrected.

Description

TOOL MACHINE WITH AT LEAST TWO PLANAR ENGINES

description

The invention relates to a machine tool according to the preamble of patent claim 1.

In WO 2007/093070 A1, a machine tool is described in which a tool or workpiece carriage is guided instead of a conventional stack of linear axes by means of a planar guide, which allows directions of movement in the X and Y directions simultaneously. This planar guide is non-contact, designed for example as a magnetic guide, as an aerostatic guide or as a hydrostatic guide. The adjustment of the guide carriage can according to one in the

WO 2007/093070 A1 disclosed option by means of a surface drive.

Such a surface drive is described, for example, in WO 2009/105071 A2 and usually has a planar stator (secondary part) which interacts with a planar rotor (primary part). By means of such a planar drive adjustment with high acceleration in the X and Y directions is possible.

In DE 10 2008 059 813 A1 a machine for non-contact structuring of substrates by means of a laser beam (laser-scribing system) is shown. The laser is guided along a conventional stack of linear axes X, Y. These linear axes are each designed with a planar motor.

A disadvantage of the solutions according to the publications WO 2009/105071 A2 and DE 10 2008 059 813 A1 is that for controlling a rotational degree of freedom about an axis normal to the driven axes, an additional drive is required.

In contrast, the invention has for its object to provide a machine tool that allows flexible control. This object is achieved by a machine tool having the features of patent claim 1.

Advantageous developments of the invention are the subject of the dependent claims.

According to the invention, the machine tool for machining or forming machining of workpieces has a tool or workpiece carriage, which is guided movably on a frame at least along two mutually perpendicular axes by means of a drive. The leadership of the carriage is designed as a non-contact surface guide and the drive as a planar motor. According to the invention, at least two planar motors are associated with the carriage, each of which independently enables an adjustment of the carriage along the surface guide in the direction of the two axes.

The machine tool is preferably provided for forming and / or machining of workpieces. In the latter case, the machine tool has a spindle, via which a tool is driven. Accordingly, according to the invention, the carriage can be moved in both axial directions, so that a rotary axis can be realized without additional drive.

Such a machine tool can be formed with very high rigidity and thus allows a high cutting volume with very high dynamics in speed and acceleration.

The planar drive is preferably designed so that at least a force of 1000 N is transferable.

In a particularly preferred embodiment, the surface guide is designed as an aerostatic or hydrostatic guide.

The guidance of the carriage on the frame is particularly precise when a surface guide executed on this has several guide surfaces on which guide areas of the carriage are guided. Accordingly, the support / guide of the carriage over a plurality of spaced-apart areas.

The Applicant reserves the right to make independent claims on this area management over several management areas.

In a variant of the invention, each surface engine is designed with a secondary part and a primary part, the latter being arranged on the shed or on the frame.

It is preferred if the secondary regions of the planar motors are formed within the guide region. Alternatively, the guide region can also be designed such that it is formed outside the secondary part region. That is, the secondary part surfaces and the bearing surfaces are formed separately from each other, while they are designed in the same range in the former alternative.

The dynamics of the machine tool can be further improved if the carriage is designed with a weight compensation. This weight compensation can be formed for example by a belt arrangement, a cable arrangement, a chain arrangement, a shear kinematics or a vacuum bellows.

In one embodiment, the machine tool is designed with a measuring system for detecting the travel of the carriage. This measuring system can be, for example, a dragged measuring kinematics, a mirror interferometer, a cross-grating measuring system (KGM). The rotational movement can be detected via a gyro compass or, if necessary, or via the motor feedback.

A cross grid of the cross grid measuring system can be carried out on the frame or on the slide. In this case, one or more read heads can be assigned to this cross grid.

The carriage may have a guide region in which or outside of which the secondary part regions are formed. The machine tool may be formed with an axle cover which is designed as a sliding plate or as a sliding / rolling plate.

In a specific embodiment, the machine tool is designed with four surface guides, between which primary parts / secondary sections of the planar motor and at least one read head or a cross grating of the grating measuring system are arranged.

To increase the precision of the carriage can be performed with a wrap on the frame.

In a further embodiment, the machine tool is designed with four planar motors for adjusting the carriage, wherein the relative positioning of the planar motors is carried out so that they together form approximately a square or a rectangle.

In principle, the machine tool can be further developed in the following way:

It can be provided as a quill a third axis, which passes through an opening of the guide body / frame.

The measuring system can be arranged behind this guide body.

In principle, it is also possible to provide the motor or motors behind the guide body.

The machine tool can be provided with an automatic tool change.

It can be configured frame side, a third axis. In principle, the machine tool can of course also be designed with a fourth or fifth axis.

According to a further variant of the invention, a plurality of slides can be synchronized or guided independently of one another on the guide base body of the frame.

In the case in which the stator is to be used as a guide surface, it is advantageous for the required precision, if first the stator is molded or non-magnetic material, such as austenitic steel, V2A glued and then revised and lapped. Optionally, a Fertigabformen done, where this is done in the μ range.

In this procedure, for example, cooling channels can be integrated into the impression material or the base body and then the magnets are applied thereto. In principle, it is also possible to integrate the cooling channels in a template for the magnets.

Preferred embodiments of the invention are explained in more detail below with reference to schematic drawings. Show it:

Figure 1 is a three-dimensional schematic diagram of the structure of a machine tool according to the invention;

FIG. 2 shows the basic structure of a carriage guide of a machine tool according to FIG. 1;

Figure 3 variants of the structure of Figure 2;

Figure 4 shows a concrete solution of a guide and a drive of a carriage of a machine tool according to Figure 1;

FIG. 5 shows a modification of the concept according to FIG. 4;

FIG. 6 shows the basic structure of an exemplary embodiment of a measuring system of a machine tool according to FIG. 1;

FIG. 7 shows a variant of the measuring system according to FIGS. 6 and 7;

FIG. 8 shows a cover of the machine tool according to FIG. 1;

FIG. 9 shows an alternative cover for a machine tool according to FIG. 1; Figure 10 shows an embodiment of a machine tool with a carriage which is driven by four planar motors and

1 1 shows a possibility for weight balance of the carriage of a machine tool according to FIG. 1

A machine tool 1 shown in Figure 1 has a frame 2, which may for example consist of a stone material or the like. On a guide body 4 of the frame 2, which extends in the illustration of Figure 1 in the vertical direction, a carriage 6 is guided by means of a surface guide and adjustable via planar motors. The carriage 6 carries a spindle 8, in which, for example, a milling tool 9 or the like can be clamped. On the frame 2, a workpiece carrier 10 is further mounted, on which the workpiece to be machined (not shown) is firmly clamped.

The machine tool 1 further has a tool magazine 12 which holds the tools 9 required for the different machining tasks. By means of a conveyor device integrated into the tool magazine 12, the respectively required tool 9 can be brought into a transfer position and then transferred to the spindle 8 via a swivel arm 14 or the like. The structure of such tool magazines 12 is known, so that further explanations are unnecessary.

The flat guide of the carriage 6 explained in detail below is designed so that it can be moved at least in the X and Y directions. In addition, a compensation for the Z-axis according to FIG. 1 can take place.

The workpiece carrier 10 is mounted in the illustrated embodiment in the Z-direction movable on the frame 2 and further has a rotary axis, which allows pivoting of the workpiece about the X-axis.

Of course, both the workpiece carrier 10 and the carriage 6 can be made adjustable in other axes.

To protect the carriage guide this is provided with a cover 15. FIG. 2 illustrates the basic structure of the surface guide and the arrangement of the planar motors of the machine tool according to FIG. Figure 2a shows the guide body 4, which has an opening 16 through which the spindle 8 extends therethrough. In Figure 2c, the guide body 4 is shown from the back.

The guide body 4 has in the illustrated embodiment two located above the opening 16 guide surfaces 18a, 18b, which perform a dual function in the illustrated embodiment. They serve on the one hand as a stator for the two planar motors whose primary parts 20a, 20b are arranged on the longitudinal edges of the carriage 6 located at the top or bottom in FIG. On the other hand, the guide surfaces 18a, 18b are also part of the surface guide of the carriage 6, which are formed by aerostatic bearings.

These aerostatic bearings are known from the aforementioned prior art and DE 10 2008 019 371 A, so that further explanations are dispensable. Specifically, in the illustrated embodiment, the guide of the carriage 6 via four arranged on the upper and lower longitudinal edges of the carriage 6 aerostatic bearing pads 22a, 22b, 22c, 22d, each forming an aerostatic bearing with the guide surfaces 18a, 18b. The bearing pads 22a, 22d and 22c, 22b are arranged at a maximum support distance from one another, so that optimal guidance is provided by the guides located above and below the aperture 16 with minimal space requirements. Of course, a different design of the guide area (bearing pads 22, guide surface 18) is possible to improve the horizontal support. In the concrete solution, the vertical support is significantly greater than the support in the horizontal direction.

The two planar motors (primary parts 20a, 20b and the stators integrated in the guide surfaces 18a, 18b) can each be adjusted in the X and Y directions, so that the rotational degree of freedom in the Z direction can be compensated. Since the stator is formed by a magnet arrangement, in particular a multiplicity of permanent magnets, and the stator surface simultaneously acts as a guide surface, this area must be manufactured with high precision, as explained in the introduction. It is important to ensure that the attraction between the stator and primary part is as low as possible and at least for the Sled in direction, altitude and attack point remains constant. In principle, it is also possible to minimize the attraction forces in that the planar motors are executed with a double comb, wherein the motor is arranged both on the front and on the rear side of the guide body 4.

Since the stator is run over by the aerostat, it must be ensured that this guide surface area is kept free of contamination (chips, coolant / lubricant).

Not shown in Figure 2 is a weight balance for the carriage 6, which can be done by the elements described above (belt assembly, cable arrangement, chain arrangement, Scherenkinematik etc.).

In the embodiment shown in Figure 2, the planar motors or their primary parts 20a, 20b between each two adjacent storage fields 22a, 22d and 22b, 22c are arranged. FIG. 3 shows two variants in which the primary parts 20a, 20b of the planar motors are respectively arranged below two horizontally adjacent bearing fields 22a, 22d or 22b, 22c and extend approximately over the length of the carriage 6 (FIG. 3a). FIG. 3b shows a variant in which the two primary parts 20a, 20b are arranged in the Y-direction between the vertically adjacent bearing fields 22d, 22c and 22a, 22b. The size of the planar motors is based on the respective force that has to be transmitted via the slide (> 1000 N) and can therefore be used i.a. be limited by the surface of the primary parts 20 and the corresponding configuration of the stator.

Figure 4 shows a schematic view for explaining the guidance and the drive of the carriage 6 in a view from behind, that is from the back to the guide body 4, wherein the individual components are shown transparent. The relative arrangement of the guide surfaces and the two planar motors corresponds approximately to the embodiment according to FIG. 3b. Marked with thin solid lines is a guide region 24, that is to say the region in which the bearing fields 22a, 22b, 22c, 22d move during the adjustment of the carriage 6. Also shown is a secondary portion 26, which by the magnets, for example by the permanent magnets is formed and which practically reflects the travel range of the planar motors. According to this representation, the secondary portion 26 is approximately the same size or at least a subset of the guide portion 24, so that the aerostatic bearing and / or the other storage and the planar motors are arranged in the same area. In the concrete solution, the secondary part region 26 is formed on the guide body 4, while the two primary parts 20a, 20b are respectively arranged on the slide between the bearing fields 22a, 22b or 22c, 22d.

As a measuring system in this embodiment, a cross-grating measuring system (KGM) is formed. In this case, a cross grid 28 between the two primary parts 20a, 20b in the carriage 6 is arranged. With the cross grating 28 cooperating reading heads 30 of the KGM are then provided corresponding guide body side.

FIG. 5 shows a modification of the concept shown in FIG. Accordingly, the secondary part region 26 is disposed approximately centrally on the guide body side, while two guide regions 24a, 24b are arranged outside, specifically above and below the secondary part region 26. That is, in this embodiment, the guide surfaces and the secondary part are arranged at different positions. Also in the embodiment according to FIG. 5, the two primary parts 20a, 20b are integrated in the carriage 6. In this concept, however, the bearing fields 22 are arranged relatively far apart from the primary parts 20a, 20b in the respective guide regions 24a, 24b.

An advantage of such a solution is that the production of the aerostatic bearing fields is simplified because the integration of the stator magnet does not have to be considered. The disadvantage, however, is that the dimensions are increased compared to the embodiment according to FIG. Thus, the dimension is about three times as large as the stroke, whereby the scalability of the stroke is limited - these disadvantages are not present in the embodiment of Figure 4 or to a lesser extent. In this variant, however, the production of the bearing surfaces and the stator due to the integration of these two elements is possible only with great effort. In the embodiment according to FIG. 5, a KGM with a construction corresponding to the exemplary embodiment in FIG. 4 is realized.

The basic structure of such a KGM will be explained with reference to FIGS. 6 and 7. FIG. 6a shows a schematic diagram of the rear side of the carriage 6, while FIG. 6b shows the guide body 4 with its guide surface. In this case, a structure according to the embodiment shown in Figure 4 is shown - that is, the guide portion 24 corresponds largely to the secondary portion 26th

The two primary parts 20a, 20b are integrated into the carriage 6 according to FIG. 6a. The storage fields 22a, 22b, 22c, 22d are arranged above or below the primary parts 20a, 20b. The cross grid 28 is located approximately in the middle between the primary parts 22a, 22b.

On the guide body side, at least four, in the present case five read heads 30, of which one is active, are assigned to this cross grid 28. Shortly before an active reading head leaves the cross grating 28 during the movement of the carriage 6, it is synchronized with a second reading head 30, so that it is possible to switch over to the now-active second reading head when leaving the first-mentioned reading head.

In principle, it is preferred if the reading head position is arranged approximately in the spindle / sleeve axis, so that the accuracy is increased.

In the illustrated embodiment, the read heads 30 are in the secondary region 26, that is, within the magnet assembly - the power reduction is relatively low.

The cross grid size may be, for example, about 400 x 400 mm.

The positioning of the reading heads 30 can in principle be designed so that the aerostat never passes over the respective reading head. It is also possible to design the positioning so that the aerostat can drive over the read heads - this allows a scaling of the respective axis, the vertical axis is formed for example by a third read head row. In this case, however, preferably only one read head is run over, which is currently not active, so that there is no limitation in accuracy.

FIG. 7 shows a variant in which the reading heads 30 are integrated in the slide, so that the cross-grating is correspondingly formed on the guide body side.

In this variant too, some of the reading heads 30 are not arranged in the spindle axis, so that the yawing of the axes has the same effect as in the variant according to FIG. The disadvantage, however, is that the frame side, a considerable space requirement for the cross grid is required, since this must be integrated into the magnet assembly of the secondary section. The required in a KGM glass plate can be relatively difficult to be integrated into the secondary region 26, so that this glass plate should be placed in the field of aerostatics.

Figure 8 shows a detailed view of the cover 15 for the carriage 6 and its guide and drive components. In this embodiment, the cover 50 is designed in a conventional manner by sliding panels. Such an embodiment requires a comparatively large machine panel, so that the telescopic sliding surface has space behind it. This builds very wide and also worsens the accessibility. Furthermore, a complex support structure for the tool change system is required, which also protrudes relatively far.

This disadvantage can be overcome by a variant according to FIG.

Figure 9 shows a plan view of the guide body 4 and the carriage 6. Accordingly, the cover 15 is at least in the horizontal direction (X-axis) designed as a roll plate 32. In this way, the lateral Achshubskalierung is easily, the outer dimensions then correspond at least in the X direction to the stroke of the carriage 6. By the variant of Figure 9 can thus achieve a massive reduction of the cover 15.

In the embodiments described above, two planar motors were used. FIG. 10 shows a variant with four planar motors 34a, 34b, 34c, 34d for Drive of the carriage 6. In these variants, the primary parts 20a, 20b, 20c, 20d are integrated into the carriage 6. This is approximately diamond-shaped in the view according to FIG. 10, the primary parts 20 being arranged in the corner regions. That is, the connecting lines of the primary parts 20b, 20d and 20a, 20c are approximately perpendicular to each other. The associated secondary sections 26a, 26b, 26c, 26d are then arranged corresponding guide body side. The guide region 24 is located centrally between the secondary part regions 26, so that, correspondingly, the aerostat is formed separately from the secondary part regions 26 in the region identified by the reference numeral 36.

As explained above, a weight balance of the carriage is advantageous in some cases. In the exemplary embodiment shown in FIG. 11, additional primary parts 38a, 38b of additional planar motors 34 are provided for weight compensation, ie compensation of the weight of the carriage in a variant according to FIG. 7, each of which has only one direction of action in one of the axes present case in the direction of the Y-axis (vertical), have. The control of the primary parts 38a, 38b of these compensation Planarmotoren then takes place such that the weight of the carriage is compensated. Accordingly, these motors must be commutated according to the position of the carriage 6, as the positions of the north and south poles of the stator are movable relative to the assignments.

As explained above, the attraction forces generated by the planar motors should be as low as possible and always remain constant for the carriage 6. This can be carried out with a wrap-around, which engages over the guide body 4 in the region of the opening 16 or behind. As a counterweight, as explained, a belt arrangement, a cable arrangement, a chain arrangement, the concept explained with reference to FIG. 1, or any other weight compensation can be used.

In the case where the guide portion 24 approximately corresponds to the secondary portion 26, a precise machining of the magnetic surface by grinding, lapping and possibly a sliding guide coating is required. The disadvantage, however, is a heat development in the management area. As explained, the measuring system can also be designed with a dragging kinematics or a mirror interferometer. Both variants have a very good measurement accuracy, but are relatively expensive and expensive. To measure the rotational degree of freedom during balancing, a gyroscope and / or gyroscope can be used.

In the region of the carriage 6, a third axis (Z-axis) can be realized via a quill.

The measuring system can be arranged behind or in front of the guide body 4.

In principle, it is also possible to guide a plurality of the above-described carriage 6 on a guide body, so that a plurality of workpieces can be processed simultaneously.

For the fall protection the aerostat can be designed with a quick exhaust.

Disclosed is a machine tool in which a carriage is guided and driven via a surface guide and a planar motor. It can be used two planar motors, which are adjustable in two axes, so that a rotational degree of freedom can be compensated.

REFERENCE CHARACTERS:

1 machine tool

2 frame

4 guide body

6 sleds

8 spindle

9 tool

10 workpiece carriers

12 tool magazine

14 swivel arm

15 cover

16 breakthrough

18 guide surface

20 primary part

22 aerostatic storage fields

24 leadership area

26 secondary section

28 cross grid

30 reading head

32 roll plate

34 Planar motor

36 Aerostatic Areas

38 Primary part of a compensation planar motor

Claims

claims

1 . Machine tool, preferably for machining or forming machining workpieces, with a tool or workpiece carriage (6) which is at least along two mutually perpendicular axes by means of a drive movable on a frame (2), wherein the guide as non-contact surface guide is executed and the drive has a planar motor (34), characterized in that the carriage (6) at least two planar motors (34) are associated, each allow an adjustment, along the surface guide in the direction of the two axes.

2. Machine tool according to claim 1, wherein the surface guide comprises at least one aerostatic or hydrostatic bearing.

3. Machine tool according to one of the preceding claims, wherein the surface guide more on the frame (2) or on the carriage (6) formed

Guide surfaces (18), which interact with each camp fields (22) of the carriage or the frame together.

4. Machine tool according to one of the preceding claims, wherein each planar motor (34) has a secondary portion (26) and a primary part (20), wherein the primary part (20) is formed on the carriage side or frame side.

5. Machine tool according to claim 4, wherein a secondary portion (26) of the planar motors (34) in the guide region (24) is formed.

6. Machine tool according to one of the claims 1 to 4, wherein the one or more guide portions (24) outside one or more secondary part regions (26) are formed.

7. Machine tool according to one of the preceding claims, with a weight balance for the carriage (6).

8. Machine tool according to one of the preceding claims, with a measuring system for detecting the adjustment path, which is preferably a towed measuring kinematics, a mirror interferometer or a cross grating measuring system.

9. Machine tool according to claim 8, wherein a cross grid (28) of the cross-grating measuring system on the frame (2) or on the carriage (6) is formed and read heads (30) are arranged in accordance schütten- or frame side.

10. Machine tool according to one of the preceding claims, with a guide region (24) of the carriage, in or outside of which the secondary part region (26) are formed.

1 1. Machine tool according to one of the preceding claims, with a cover (15) which is designed as a sliding plate or as a rolling plate (32).

12. Machine tool according to one of the preceding claims, with four surface guides, between which the primary parts (20) of the planar motors (34) and at least one read head (30) or a cross grid (28) of a cross grid measuring system are arranged.

13. Machine tool according to one of the preceding claims, wherein the carriage (6) with a wraparound on the frame (2) is guided.

14. Machine tool according to one of the preceding claims, with four planar motors (34) for adjusting the carriage, wherein the relative positioning of the planar motors (34) takes place so that they jointly span about a quadrangle.

15. Machine tool according to claim 7 or one of the related back to this claims, with additional planar motors for weight balance for the carriage.