EP1797344B1 - Gas bearing-mounted arrangement of bodies that can be displaced relative to one another - Google Patents

Abstract

The invention relates to a gas bearing-mounted arrangement of bodies, which can be displaced relative to one another, with an inner body (1; 101; 201; 301; 401) having a bearing surface (14'; 114'; 214'; 314'; 414') that, at least in sections, extends in a curved manner, and with an outer body (3; 203; 303; 403), which at least partially surrounds at least the curved section of the bearing surface (14'; 114'; 214'; 314'; 414') of the inner body (1; 101; 201; 301; 401). The inner body (1; 101; 201; 301; 401) is, in its bearing surface (14'; 114'; 214'; 314'; 414'), provided, at least in areas, with microholes (140, 141, 142, 143; 140'; 240; 350, 351, 352, 353; 450, 451, 452, 453), which define a gas bearing between the inner body (1; 101; 201; 301; 401) and the outer body (3; 203; 303; 403), these microholes (140, 141, 142, 143; 140'; 240; 350, 351, 352, 353; 450, 451, 452, 453) leading into a gas supply structure of the inner body (1; 101; 201; 301; 401). The invention is characterized in that the microholes (140, 141, 142, 143; 140'; 240; 350, 351, 352, 353; 450, 451, 452, 453) are made in the inner body (1; 101; 201; 301; 401) starting from the side of the bearing surface (14'; 114'; 214'; 314'; 414').

Description

The invention relates to a gas-bearing arrangement of relatively movable bodies and a method for producing a gas bearing for such an arrangement.

It is known to provide an air-bearing arrangement of relatively movable bodies, in which the air supply of the air bearing formed thereby takes place through the inner body made of sintered material. However, such sintered body are limited in their carrying capacity and rigidity. In addition, the air cushion formed by the air flowing out of the sintered material in the air bearing is very inhomogeneous, whereby the storage is very indefinite.

From the DE 44 36 156 C1 An aerostatic bearing is known as a combined axial and radial bearing in which the Air supply structure is provided for the aerostatic bearing in the outer stationary bearing body, wherein the inner bearing body is formed as a rotational body. In this known aerostatic bearing the introduction of the microholes does not take place from the bearing side, but from the side facing away from the bearing side of the outer body, in which the gas supply structure is provided.

The EP 0 686 781 A2 discloses a heatable and coolable roll with virtually frictionless support. Such a role consists of a cylindrical core which is provided at its periphery with axially parallel longitudinal grooves. The core is surrounded by a cylindrical sleeve which has substantially radially extending so-called supply holes, which open into the axially parallel grooves, and having the so-called discharge holes, which open into the paraxial grooves. Around the core provided with the sleeve around a roller shell is arranged, wherein between the sleeve and the roller shell, a bearing gap is formed. At the axial ends of this arrangement of core, sleeve and roller shell each an end-side side cap is arranged, which are each firmly connected to the core and the cylindrical sleeve, but extending in the radial direction to the outer peripheral surface of the roll shell and laterally abut this seems. The two side caps are provided with outgoing from an axial bore radial channels, which are in the assembled state of the roller in fluid communication with the paraxial grooves. The core is also provided in its interior with radial bores, which connect a central axial bore of the core with the paraxial longitudinal grooves. The introduced through the respective central bore of the core and the one side cap pressure fluid penetrates through the corresponding radial bores in the paraxial grooves, flows from there through first radial holes in the bearing gap, passes from the bearing gap second radial bores of the sleeve again from the bearing gap and into the second longitudinal grooves and leaves them through corresponding outlet openings. Although the sleeve is located on the core, but this sleeve is not applied gas-tight on the core. The axially parallel grooves open at their axial ends prevent the creation of a gas-tight closed gas supply structure between the core and the sleeve. In the circumferential direction, feed openings and outflow openings alternate. Thus, pressure peaks occur in the bearing gap in the region of the inflow openings, whereas pressure drops occur in the circumferential direction immediately adjacent in the area of the outflow openings.

The US 4,744,676 A discloses an annular gas bearing having a cylindrical inner bearing body formed of a cylinder of porous material compressed on its surface. In the compacted surface blind holes are introduced, which penetrate through the compacted surface into the porous material and from which introduced into the cylinder and passing through the porous material pressure fluid can escape into the bearing gap surrounding the cylinder. A defined gas supply structure is not provided in this cylindrical body.

Object of the present invention is to provide a gas-bearing arrangement of relatively movable bodies, which has an outer moving body, which can also reach high speeds of movement and has a low-inertia startup behavior. Furthermore, it is an object to provide a method for producing a gas bearing for such an arrangement.

The first object is achieved by the gas-bearing arrangement with the features of patent claim 1.

If the microholes are introduced from the side of the bearing surface into the inner body, then the production costs are significantly reduced.

The particularly advantageous preferably two-part design of the inner bearing body consisting of the support body and the sleeve or bearing shell makes it possible to achieve both a high load capacity of the inner bearing body, as well as to allow the introduction of high-precision micro holes in the storage area. The support body can be configured in the required dimensional stability, without having to take into account the required for the introduction of micro holes in the bearing surface small wall thickness in this area consideration. This small wall thickness is provided in the gas-tightly applied to the support sleeve or bearing shell. In these can then be easily introduced the microholes.

Advantageous developments of the arrangement according to the invention are specified in the further subclaims.

It is particularly advantageous if the microholes are laser drilled microholes.

Furthermore, it is advantageous if the sleeve or bearing shell is provided on its outer circumference with a friction-reducing coating. Such a coating provides runflat performance if, in the event of overload, bearing surface contact should occur between the relatively moving bodies.

It is also particularly advantageous if the microholes of a radial plane are not exactly aligned radially, but are inclined at an angle to the radial direction. In this way, the gas cushion can be set in motion in the bearing in a desired circumferential direction and a predetermined direction of contact for the outer body can be determined.

In another advantageous embodiment, the inner body is a body of revolution and the outer body is stationary.

In this case, the outer body is provided in its bearing surface opposite the inner body with an inner peripheral groove into which at least one connected to a compressed gas source Gaszuführkanal, and the inner body is in an axially central portion of the outer body opposite bearing surface with at least one gas inlet bore the gas supply structure provided, wherein the at least one gas inlet bore of the Inner circumferential groove opposite. In this way, the pressurized gas is introduced from the outside into the rotating inner body, without the rotating inner body having to have a compressed gas connection mechanically connected to the rotating inner body, whereby the friction in the rotation of the inner body is substantially reduced.

Alternatively, the inner body is provided in its bearing surface facing the outer body with an outer circumferential groove, wherein at least one gas inlet hole of the gas supply structure opens into the Außenumfangsnut, and wherein the outer body in an axially central portion of the inner body opposite bearing surface with at least one in this bearing surface opening gas supply channel is provided, which is connected to a compressed gas source, wherein the at least one gas supply channel of the outer circumferential groove opposite.

Both aforementioned embodiments have the advantage that the inner rotary body is not mechanically connected to a compressed gas source, which significantly reduces the rotational friction of the inner body. The arrangement of the inner circumferential groove or the outer circumferential groove substantially in the - viewed in the axial direction - central portion of the respective bearing surface causes the flow resistance along the bearing gap in the respective axial direction is so high that the gas supplied from the outer body does not escape through the bearing gap, but through which at least one gas inlet bore of the inner body flows into the gas supply structure provided in the inner body and exits from there through the microholes in the bearing surface of the inner body into the bearing gap. For this purpose, the gas-bearing arrangement is to be dimensioned so that the flow resistance between the at least one gas inlet bore and the opening into the bearing gap microholes is lower than that Flow resistance between the inner circumferential groove or the outer circumferential groove and the respective axial end of the common bearing surface.

The part of the problem relating to the method is achieved by the method features specified in patent claim 15.

Due to the airtight application of the sleeve or the bearing shell on the support body, it is possible to prefabricate the sleeve or bearing shell with the desired dimensions of a material that allows a quick and easy insertion of the microholes using the high-energy radiation, while the support body of a Material can be manufactured, which has optimal properties for the load capacity.

It is particularly advantageous if the sleeve or the bearing shell can be brought to a desired dimension after application to the support body and prior to the introduction of the micro-holes by means of cutting and / or grinding machining of the outer circumference. As a result, the sleeve or the bearing shell can first be applied to the support body in a statically stable form, preferably shrunk on, or adhesively bonded. The thin wall thickness required for optimum introduction of the microholes is therefore produced only after the sleeve or bearing shell has been applied to the support body by the machining and / or grinding of the outer circumference of the sleeve.

However, the sleeve can also be formed, for example, as a high-precision molding part of the inner circumference of the outer body designed as a rotational body.

In an advantageous development of this method, the high-energy radiation source is formed by a laser device, so that the micro-holes by means of a laser beam are introduced into the sleeve or bearing shell.

Fig. 1

einen Längsschnitt durch eine erste erfindungsgemäße gasgelagerte Anordnung;

Fig. 2

einen Querschnitt gemäß Linie II-II in Fig. 1;

Fig. 3

einen Querschnitt analog Fig. 2 durch eine alternative Ausführungsform dieser ersten Anordnung;

Fig. 4

einen Querschnitt durch eine Abwandlung der ersten Ausführungsform der erfindungsgemäßen gasgelagerten Anordnung;

Fig. 5

einen Querschnitt analog Fig. 4 durch eine alternative Ausführungsform dieser zweiten Anordnung;

Fig. 6

einen Längsschnitt durch eine weitere Ausführungsform der vorliegenden Erfindung mit rotierendem inneren Körper und

Fig. 7

einen Längsschnitt durch noch eine weitere abgewandelte Ausführungsform mit einem rotierenden inneren Körper.

The invention will be explained in more detail by way of examples with reference to the drawing. In this shows:

Fig. 1

a longitudinal section through a first gas-bearing arrangement according to the invention;

Fig. 2

a cross section according to line II-II in Fig. 1 ;

Fig. 3

a cross section analog Fig. 2 by an alternative embodiment of this first arrangement;

Fig. 4

a cross section through a modification of the first embodiment of the gas-bearing arrangement according to the invention;

Fig. 5

a cross section analog Fig. 4 by an alternative embodiment of this second arrangement;

Fig. 6

a longitudinal section through another embodiment of the present invention with rotating inner body and

Fig. 7

a longitudinal section through yet another modified embodiment with a rotating inner body.

In Fig. 1 is embodied as an axle formed and hereinafter also referred to as bearing body inner body 1, which in a conventional manner in a schematic and shown with dashed lines shown housing 2 is supported. The inner body 1 has a supporting body 10 clamped in the housing. At its protruding from the housing 2 side of the support body 10 is provided with a circular cross-section receiving portion 12 for a bearing sleeve 14. The bearing sleeve 14 is shrunk onto the receiving portion 12 and connected in this way gas-tight with the support body 10.

The support body 10 is provided in the region of the receiving portion 12 with recesses formed as circumferential grooves 120, 121, 122, 123. Each of these provided on the outer circumference of the receiving portion 12 circumferential grooves 120, 121, 122, 123 is connected via at least one radial bore 124, 125, 126, 127 with an axial bore 11 of the support body 10. In this way, from a pressurized gas source not shown in the axial bore 11 introduced pressurized gas, in particular compressed air, through the radial bores 124, 125, 126 and 127 in the respective associated annular grooves 120, 121, 122, 123 occur and build there a corresponding gas pressure.

The sleeve 14 is provided in the region of the annular grooves 120, 121, 122, 123 with radially extending microholes 140, 141, 142, 143, which, starting from the bearing surface 14 'on the radial outer circumference of the bearing sleeve 14, through the wall of the bearing sleeve 14 therethrough into the associated annular groove 120, 121, 122, 123 lead.

As Fig. 2 shows, a plurality of radial bores 140, 141, 142, 143 are provided over the circumference of the bearing sleeve in the region of each annular groove. The pending in the respective annular groove 120, 121, 122, 123 compressed air or the pressurized gas there occurs from the microholes 140, 141, 142, 143 in between the formed by the radial outer peripheral surface of the bearing sleeve 14 bearing surface 14 'and the opposite bearing surface on the inside of a bearing bore of the outer rotary body. 3 formed gap 30 and forms there an air cushion, which supports the outer rotary body 3. The excess pressurized gas exits at the axial ends of the bearing gap 30. In this way, the aerostatic bearing is formed.

Fig. 3 shows an enlarged section of a section similar to in FIG Fig. 2 However, in this embodiment, the micro holes 140 'are inclined at an angle α to the radial direction R. In this embodiment, the gas cushion formed in the bearing gap 30 rotates in the direction of the arrow U and thus ensures a predetermined start-up behavior of the outer rotary body 3 in the direction of the arrow U.

To produce the gas bearing, the support body 10 is first prepared by providing the gas supply structure formed by the axial bore 11, the radial bores 124, 125, 126, 127 and the annular grooves 120, 121, 122, 123 in the support body 10 of an inner bearing body 1. Then, the bearing sleeve 14 is airtight attached to the circular portion 12 of the support structure 10, for example, shrunk or glued, so that the bearing sleeve 14 is gas-tightly connected to the support structure 10. Subsequently, the wall thickness of the annular bearing sleeve 14 is reduced by machining and / or grinding its outer periphery to a predetermined thickness d, which is sufficiently low to allow easy insertion of microholes by means of a high-energy radiation source, such as a laser device. Following this material processing of the bearing sleeve 14, a plurality of microholes 140, 141, 142, 143 are introduced into the bearing sleeve 14 by means of the high-energy radiation source from the side of the bearing surface 14 ', wherein the radiation source is radially outside the inner Bearing body 1 is located. Preferably, a friction-reducing coating is applied to the bearing surface 14 'before or after the introduction of the microholes. Subsequently, the outer rotational body is still pushed onto the inner bearing body and, if necessary, secured in a known manner in the axial direction against displacement.

In Fig. 4 is a modified embodiment of the first arrangement similar Fig. 2 shown. Here, the bearing sleeve 114 is not provided on its entire circumference with the trained as micro holes radial bores 140, but only in a peripheral portion of about 170 °. This gas-bearing arrangement with the bearing sleeve 114 is designed as a deflection bearing for a guided on the gas cushion over the bearing surface 114 'to the inner bearing body 101 around material web 4, wherein the material web 4 in the arrow direction around the fixed bearing body 101 runs around.

A modification of a fixed bearing body 201 is shown in FIG Fig. 5 shown. There, the bearing body 201 is formed from a supporting body 210 designed as a support beam. The support body 210 is provided in a portion with an arcuate or curved in cross section formed bearing shell 214 which is connected to the bearing body 210 airtight, for example glued, is. The bearing shell 214 has a likewise curved bearing surface 214 ', over which a material web 204 rotates. The material web 204 moves in the direction of the arrow relative to the stationary bearing body 210, wherein the compressed gas flowing out of the microholes 240 provided in the bearing shell 214 carries the material web 204.

The support body 210 is analogous to the support body 10 with a pressure gas supply bore 211 extending in the axial direction and outgoing from this pressure gas bore 211 Provided radial bores 224, which each open into a groove-like compressed gas chamber 220, in which open the micro holes 240.

In the examples of 6 and 7 is the respective inner body 301, 401 formed as a rotational body, while the respective outer body 303, 403 with respect to the rotational movement stationary, ie stationary, is arranged. The supply of the compressed gas for acting in the respective inner body 301, 401 gas supply structure for acting on the respective Druckgaspolster between the opposing bearing surfaces 313 'and 314' or 413 'and 414' takes place from the outside by a gas supply channel 340 and 440, respectively in the outer body 303 or 403 is provided.

In Fig. 6 an embodiment is shown in which the outer body 303 is provided in its inner body 301 opposite bearing surface 313 'with an inner circumferential groove 342. Into the inner circumferential groove 342, the gas supply passage 340 opens. Opposite the inner circumferential groove 342, there is provided at least one gas entrance hole 311 'in the bearing surface 314' of the inner body 301, which is connected to the gas supply structure 311 formed in the support body 310 of the inner body 301. In this way, the compressed gas introduced into the inner circumferential groove 342 from a compressed gas source via the gas supply passage 340 can enter the gas supply structure 311 of the inner body 301 through the gas inlet bore 311 'and from there to the microholes 350, 351, 352 provided in the bearing sleeve 314. 353 passed, through which it enters the bearing gap 330 to produce there the compressed gas cushion for storage.

In the embodiment according to Fig. 7 the circumferential groove is not in the inner periphery of the bearing surface 413 'of the outer body 403, but as the outer circumferential groove 442 in the bearing surface 414 'of the inner body 401. The gas supply passage 440 opens into the bearing surface 413' of the outer body 403 in a portion facing the outer circumferential groove 442. The gas inlet bore 411 'opens into the outer circumferential groove 442 of the inner body 401 and is also connected to the gas supply structure 411 provided in the supporting body 410 of the inner body 401. Also in this embodiment, the compressed gas flows from the compressed gas source through the Gaszuführkanal 440 in the Außenumfangsnut 442 and from there through the gas inlet bore 411 'in the gas supply structure 411 and from there through the provided in the bearing sleeve 414 micro holes 450, 451, 452, 453 in the bearing gap 430, where it forms the compressed gas cushion for storage.

Both in the embodiment according to Fig. 6 as well as in the embodiment according to Fig. 7 the inner circumferential groove 342 and the outer circumferential groove 442 are arranged in the region of the center of the axial extent L of the mutually opposite respective bearing surfaces 313 ', 314' or 413 ', 414'. The ratio between the thickness d of the respective bearing gap to the respective distance between the Innenumfangsnut 342 and the Außenumfangsnut 442 and the respective axial outer end of the respective common bearing surfaces is dimensioned so that the flow resistance of the respective groove 342, 442 directly through the respective bearing gap 330, 430 to the outside is greater than the flow resistance through the respective gas supply structure 311, 411 and the microholes connected thereto and outwardly in the axis-parallel direction, so as to ensure that the introduced into the Innenumfangsnut 342 and Außenumfangsnut 442 pressurized gas is not directly through the respective bearing gap 330, 430 escapes, but by the respective Gas supply structure 311, 411 and the associated microholes is introduced into the bearing gap.

The material webs in the FIGS. 4 and 5 can be, for example, paper webs or film webs of plastic or metal, for example aluminum, be.

Claims (18)

1. Gas bearing arrangement of bodies that are movable relative to one another, comprising

   - an inner bearing body (1; 101; 201; 301; 401) having a bearing surface (14'; 114'; 214'; 314'; 414') extending at least in sections in a curved manner and

   - an outer body (3; 203; 303; 403) that at least partially surrounds at least the curved portion of the bearing surface (14'; 114'; 214'; 314'; 414') of the inner bearing body (1; 101; 201; 301; 401),

   - wherein the inner bearing body (1; 101; 201) comprises a supporting body (10; 210), which is provided at its outer periphery with a bearing sleeve (14; 114) or bearing shell (214),

   - wherein the bearing sleeve (14; 114) or bearing shell (214) is provided at least in sections with microholes (140, 141, 142, 143; 140'; 240), which penetrate the wall of the bearing sleeve (14; 114) or bearing shell (214) and open out into recesses (120, 121, 122, 123; 220), which extend in peripheral direction, of a gas-feed supply structure of the supporting body (10; 210) in order to form gas outlet nozzles of a gas bearing, and

   - wherein the microholes (140, 141, 142, 143; 140'; 240) are introduced into the bearing sleeve (14; 114) from the bearing surface (14'; 114'; 214') side by means of a high-energy radiation source.
2. Arrangement according to claim 1,
   characterized in
   that the bearing sleeve (14; 114; 314; 414) or bearing shell (214) is mounted in a rotationally and axially fixed manner on the supporting body (10; 210; 310; 410).
3. Arrangement according to claim 1 or 2,
   characterized in
   that the bearing sleeve (14; 114; 314; 414) or bearing shell (214) is provided on its outer periphery in the region of the bearing surface (14'; 114'; 214'; 314'; 414') with a friction-reducing coating.
4. Arrangement according to one of the preceding claims,
   characterized in
   that the gas bearing is an aerostatic bearing.
5. Arrangement according to one of the preceding claims,
   characterized in
   that the microholes (140, 141, 142, 143; 140'; 240; 350, 351, 352, 353; 450, 451, 452, 453) are microholes bored by a high-energy radiation source.
6. Arrangement according to claim 5,
   characterized in
   that the microholes (140, 141, 142, 143; 140'; 240; 350, 351, 352, 353; 450, 451, 452, 453) are laser-bored microholes.
7. Arrangement according to one of the preceding claims,
   characterized in
   that the microholes (140') in a radial plane are not exactly radially oriented but are inclined at an angle (α) relative to the radial direction (R).
8. Arrangement according to one of the preceding claims,
   characterized in
   that the inner bearing body (1) is an axle and that the outer body (3) is a rotational body (30), which is mounted rotatably on the axle.
9. Arrangement according to claim 8,
   characterized in
   that the outer rotational body (30) is fixed in axial direction relative to the inner bearing body (1).
10. Arrangement according to one of claims 1 to 7,
    characterized in
    that the inner bearing body (1) is an axle, wherein the bearing sleeve (114) is provided only over a sub-portion of its periphery with microholes (140), and that the outer body (4) is a material web, which is deflected over the sub-portion of the inner bearing body (1) and moved relative to the inner bearing body (1).
11. Arrangement according to one of claims 1 to 7,
    characterized in

    - that the inner bearing body (201) is a beam that is provided with the bearing sleeve (214),

    - that the outer body (204) is formed by a material web, which extends over the bearing surface (214') of the bearing sleeve (214) and which moves relative to the inner bearing body (201).
12. Arrangement according to one of claims 1 to 7,
    characterized in
    that the inner bearing body (301; 401) is a rotational body and that the outer body (303; 403) is disposed in a stationary manner.
13. Arrangement according to claim 12,
    characterized in

    - that the outer body (303) in its bearing surface (313') situated opposite the inner bearing body (301) is provided with an inner peripheral groove (342),

    - that at least one gas feed channel (340), which is connected to a pressure gas source, opens out into the inner peripheral groove (342), and

    - that the inner bearing body (301) in an axially central portion of the bearing surface (314') situated opposite the outer body (303) is provided with at least one gas inlet bore (311') of the gas supply structure (311), wherein the gas inlet bore (311') lies opposite the inner peripheral groove (342).
14. Arrangement according to claim 12,
    characterized in

    - that the inner bearing body (401) in its bearing surface (414') situated opposite the outer body (403) is provided with an outer peripheral groove (442),

    - that at least one gas inlet bore (411') of the gas supply structure (411) opens out into the outer peripheral groove (442), and

    - that the outer body (403) in an axially central portion of the bearing surface (413') situated opposite the inner bearing body (401) is provided with at least one gas feed channel (440), which opens out into said bearing surface (413') and is connected to a pressure gas source, wherein the at least one gas feed channel (440) lies opposite the outer peripheral groove (442).
15. Method of manufacturing a gas bearing for an arrangement of bodies that are movable relative to one another, comprising the steps:

    a) provision of a supporting body (10; 210; 310; 410) that is provided with a gas-feed supply structure, wherein the gas-feed supply structure comprises recesses (120, 121, 122, 123; 220), which are provided in an outer peripheral portion of the supporting body (10; 210; 310; 410) and extend in peripheral direction;

    b) mounting of a bearing sleeve (14; 114; 314; 414) or an, at least in sections, curved bearing shell (214) in a gastight manner onto the supporting body (10; 210; 310; 410) to form an inner bearing body (1; 101; 201; 301; 401) in the region of the recesses (120, 121, 122, 123; 220) of the gas-feed supply structure, wherein the inner bearing body (1; 101; 201; 301; 401) forms an inner body that is at least partially surrounded by an outer body;

    c) introduction of microholes (140, 141, 142, 143; 140'; 240; 350, 351, 352, 353; 450, 451, 452, 453), which penetrate the wall of the bearing sleeve (14; 114) or bearing shell (214), into the bearing sleeve (14; 114; 314; 414) or bearing shell (214) by means of a high-energy radiation source, wherein the radiation source is situated radially outwardly of the inner bearing body (1; 101; 201; 301; 401) and the introduction of the microholes (140, 141, 142, 143; 140'; 240; 350, 351, 352, 353; 450, 451, 452, 453) is effected from the bearing surface (14'; 114'; 214'; 314'; 414') side.
16. Method according to claim 15,
    characterized in
    that the outer periphery of the bearing sleeve (14) is formed by high-precision moulding of the inner periphery of an outer body (3), which takes the form of a rotational body and surrounds the bearing sleeve (14).
17. Method according to claim 15,
    characterized in
    that the high-energy radiation source is a laser device.
18. Method according to claim 15,
    characterized in
    that prior to the step c) a cutting and/or grinding operation is carried out on the outer periphery of the bearing sleeve (14; 114; 314; 414) or the bearing shell (214) in order to achieve a defined outside diameter and/or radius of curvature of the bearing shell (214).

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