DE19904420A1 - Bearing arrangement consists of squeeze-film bearing and pneumatic bearing, one half of the bearing being constructed as oscillating surface and column of compressed air between bearing halves generating bearing power - Google Patents

Abstract

The bearing arrangement consists of a squeeze-film bearing and a pneumatic bearing. One half of the bearing is constructed as an oscillating surface (3) with an oscillating mechanism. A column of compressed air between the bearing halves generates the bearing power. The bearing half has spiral or v-shaped slots (15a -15d) for the passage of air which generate additional pressure in the column of air. An Independent claim is included for a method of driving the bearing system.

Description

The invention relates to a bearing arrangement and a method for operating a such bearing arrangement according to the preamble of the independent Claims.

So-called squeeze film bearings are known from US Pat. No. 4,666,315. In this Publication radial and axial support bearings are shown in general form work with the squeeze film effect. This effect is that the a bearing shell or the one half of a bearing as a vibration surface is formed, which is excited by an oscillation mechanism. A piezo-electric element is preferably used here, which via corresponding electrodes is contacted and by applying a high frequency AC voltage is set in bending vibrations. This piezo element sits firmly on one, swinging bearing shell. Through the  Vibration excitation of this piezo element vibrates the one bearing shell, while the opposite bearing shell is usually fixed. Hereby is caused that the between the bearing shells in an air gap Air is rhythmically compressed and decompressed, creating an air cushion forms on which the bearing shells are carried. It is known here to operate piezoelectric flexural vibrators in resonance frequency, so to reach fixed vibration nodes, d. H. air areas in the Air gap that is always compressed while other air areas are decompressed are.

Instead of the piezoelectric vibration excitation mechanism, too other vibration excitation mechanisms are used, e.g. Legs magnetostrictive or electrostrictive excitation or other suitable Excitation mechanisms.

The disadvantage of the known piezoelectric bearing, however, is that Life is severely limited. Through the constant, over the entire life the bearing acting vibration load of a bearing shell tends this causes mechanical damage, cracks or warpage, which leads to severely limits bearing life.

There are publications dealing with the problem of Deal with bearing life. For example, reference is made to US 4,545,625. where indicated that those are detrimental to the piezoelectric vibrator Mechanical changes in tension from a tube surrounding the transducer be recorded to avoid stress cracks in this transducer.

Another disadvantage of the known piezoelectric bearing is that Excitation mechanism during the entire storage period electrical energy must be supplied for the excitation of the piezo element, which the Power consumption of such a device is greatly increased.  

It is known that the developments according to US 4,666,315, US 4,592,956 and other publications have been used to provide low-friction magnetic heads on one to store under the magnetic heads rotating hard drive, but never was realized.

Such a camp constellation was therefore particularly little dynamic support of such bearing parts over a rotating bearing surface suitable. However, it was not for very high speed applications and for suitable for highly dynamic applications. The squeeze film effect Generatable stock film (air film) is usually not sufficient, thicker Load impacts that also act at high revolutions, from which keep rotating part (rotor) away.

The invention is based on the object, a bearing arrangement and a Propose a method for operating such a warehouse, which is suitable for for high-speed, rotary spindle bearings, especially at Hard drive storage to be used.

To achieve the object, the invention is based on the technical teaching characterized by the independent claims.

An essential feature of the invention is that the bearing from a combination a squeeze film warehouse with z. B. piezoelectric excitation and one Air bearing, which is at least on a storage area (either the has movable or fixed) air guide grooves or spiral grooves, the air in the space between the two bearing surfaces supply certain, defined areas and create a pressure build-up there.

The invention includes a variety of combinations and their Subcombination.  

In a first embodiment, it can be provided that an axial bearing a piezo-electrically excited bearing, which also with air-guiding spiral grooves is formed in the air gap, so that a total Thrust bearing is created, which is a combination of the two types of bearings consists.

In another embodiment of the invention it can be provided that a Radial bearing is provided so that the bearing load via a piezo electrically excited squeeze film bearing is transmitted, while at the same time The spiral grooves according to the invention are also present in this bearing gap, which form an additional pressure increase in the bearing gap and thus stable Generate bearing points or air rings, the wearing properties of such Improve camp significantly.

In a third embodiment it can be provided that both a radial and an axial bearing can be combined with each other, both the radial as well as the axial bearing component each according to the invention Air bearings with spiral grooves are assigned.

With regard to the spiral grooves, it does not matter which bearing part these are arranged. You can either use the fixed storage area or be arranged on the rotating bearing surface. But you can too be arranged on both opposite bearing surfaces.

It is therefore not necessary for the solution that the spiral grooves according to the invention, which significantly improve the bearing properties of the bearing on which fixed piezo disk are attached. You can also look at yourself rotating rotor part can be arranged.  

In a further embodiment, for which separate protection is claimed, becomes a magnetic bias of a piezo bearing essential to the invention claimed. In this variant, it is not necessary to Carrying properties of the piezoelectric bearing by means of additional improve air-guiding spiral grooves, because in this embodiment the Wearing properties can be improved by magnetic bias.

In this embodiment, it is advantageous to have one on one side of the bearing to apply magnetic bias to the rotating part because then the opposite bearing can be omitted. For example, is it a thrust bearing, then it is sufficient to have the rotating part on one side on this thrust bearing to be stored while the opposite side is completely free. To one To ensure limitation in the direction of the missing bearing part is just the magnetic bias is provided, which ensures that instead of missing axial bearing part this magnetic bias acts so that it is sufficient to axially support the rotating part on one side only, while the other side remains free.

Of course, the invention is not based on magnetic bias alone limited, because in a sub-combination it can be provided that the Piezo bearing, which is biased by the magnetic bias, still has additional air-guiding spiral grooves, which the wearing properties of this Improve camp.

Important areas of application of the present invention are high-revving Spindle bearings for miniature motors in removable disk storage, whereby Revolutions in the range from 10,000 to 50,000 Revolutions / minute are provided. Another important area of application of the present invention are the bearings of optical scanners more precisely for the rotating laser deflection optics.  

Another important application example of the present invention are So-called linear guides, in which parts against each other along a plane be shifted, whereby also the aforementioned sub-combination is claimed essential to the invention, namely such a linear guided Bearing with a magnetic preload so that only the Guidance on one side is sufficient while the opposite side is free and remains unguided.

A method for operating such a combined bearing, consisting of a squeeze film bearing and an additional air bearing component in that the first when starting up such a combined warehouse operates piezo-electric bearings alone, d. H. during the start-up period of e.g. B. 0.5 up to 1 sec only the piezo-electric bearing is replaced by appropriate Power supply excited, which makes the start-up time essential is shortened because the warehouse is practically one from the start Forms air gap and thus runs particularly low friction. This will Significant energy saved because a very smooth start-up is guaranteed and the wear of the bearing is minimized because the bearing surfaces that are used for The start of the start rest on each other with the start of excitation of the piezo electrical bearing stand out from each other and then the bearing with separate bearing shells starts up without significant friction cause.

The service life of such a bearing is thus significantly extended. It is now important that after this bearing according to the invention has started up, where only the piezo-electric bearing is effective, the electrical excitation of the Piezoelectric bearing is turned off and that then the air-guiding Component of this bearing with the spiral grooves according to the invention effective becomes. After the piezo-electric bearing has been switched off, it only works the air bearing, the spiral grooves according to the invention having a stable air film train the air bearing for the entire remaining term without the  There is a risk that the bearing shells touch and during operation to damage.

Overall, the life of such a combined bearing compared to a pure squeeze film camp, because one Squeeze film stock is a problem throughout Life of the piezoelectric flexural vibrator remains on and it stays there this results in a rapid due to stress deformation Damage can occur.

This is avoided in the method according to the invention because the piezo electrical bearings are preferably only used during the start-up phase, only the air bearing is used during the rest of the term.

However, the invention is not limited to this. It can also be provided that the squeeze film bearing with its piezoelectric excitation long time, d. H. is kept in operation over the start-up period. Such operating conditions exist for. B. if necessary, the warehouse train particularly stable, e.g. B. in notebooks, where it is special Shock absorption arrives.

It would reduce the life of the bearing, but it becomes a particularly stable air film in this combined bearing that creates it allows the bearings of such a device much higher Withstand shock loads.

Incidentally, by combining a bearing according to the invention, consisting of a piezo-electrically excited bearing and an additional one Air bearings still have the further advantage that the emergency running properties are significantly improved. There is only one piezo-electric excited bearing before, then when the electrical excitation ceases  Bearing parts damaged immediately. This is avoided in the invention, because here The bearing continues to run undamaged when the piezoelectric excitation should be omitted because of the combination according to the invention with a Air bearing (and associated spiral grooves) the air bearing remains stable in operation.

The subject matter of the present invention does not only result from the subject of the individual claims, but also from the Combination of the individual claims. All in the Documentation, including the summary, disclosed disclosures and Features, in particular the spatial shown in the drawings Training are claimed as essential to the invention, insofar as they are individual or are new in combination with the prior art.

In the following the invention is based on several ways of execution illustrative drawings explained in more detail. Here go from the drawings and its description further features and advantages of the invention Invention.

Show it:

Fig. 1A is a sectional view of a combined axial bearing,

FIG. 1b plan view of the thrust bearing of FIG. 1a,

Fig. 2a schematically, a section through a bearing according to Fig. 1a showing the vibration behavior of the piezoelectric disk,

Fig. 2B shows the top view of the piezoelectric disc with representation of the vibration node,

Fig. 3 is the same view as Fig. 2a in a higher mode of vibration,

FIG. 3b is the same view as Fig. 2b showing the higher mode of vibration,

Fig. 4 shows the top view of a comparison with FIG. 1b modified from guide die having a different shape of the spiral grooves,

Fig. 5 shows a four quadrant representation of a plan view of a combined piezo bearing according to Fig. 1b with 4 different views of the assembly of various spiral grooves,

FIGS. 6 A comparison with FIG. 1a modified embodiment,

Fig. 6b: A comparison with FIG 1b modified embodiment.

Fig. 7a: The formation of the nodal lines in an embodiment according to Figure 6b.

FIG. 7B is a comparison with FIG. 6b modified embodiment with ring-shaped electrodes,

FIG. 8a schematically, a section through a radial bearing according to the invention,

FIG. 8b, the top view of the journal bearing of FIG. 8a,

FIG. 8c A comparison with FIG. 8a extended display with indication of the spiral grooves in the radial bearing,

Fig. 9, the representation of the vibration nodes of the radial bearing of FIG. 8a in a first oscillation mode,

Fig. 10 showing the vibration modes of the radial bearing of FIG. 8a, in a second mode of oscillation

FIG. 11A is a comparison with FIG. 8c modified embodiment with an inner rotor,

FIG. 11B is a comparison with FIG. 11a modified embodiment with a modified air supply,

FIG. 12A is a sectional view of a radial bearing in an embodiment according to FIG. 8a with segment electrodes arranged on the inner circumference,

FIG. 12B is a section through the representation of Fig. 12a

Fig. 12c of the vibration mode of an embodiment according to FIG. 12a,

Fig. 12d A comparison with FIG. 12a modified embodiment with ring-shaped axially distributed over the length of arranged electrodes,

FIG. 13a schematically, a section through a rotor bearing with an axial squeeze-film bearings and magnetic bias,

FIG. 13B is a comparison with FIG. 13a slightly modified embodiment in plan view;

Fig. 14 is a section through a radial rotor bearing,

Fig. 15 is a sectional view of a combined radial and axial bearing for supporting a rotor with magnetic bias,

Fig. 16 The start-up curves of the bearing pressure drawn over the start-up time.

In FIGS. 1a and 1b show a half-bearing is a combined air-piezo bearing illustrated in a first embodiment in which the piezo bearing is generally referred to in the axial embodiment with reference numeral 1. It consists essentially of circular electrodes 2 , which are attached to a piezo-ceramic workpiece 1 a. The ceramic workpiece is formed here as a solid disc, wherein in each case a circular electrode 2 on the front and back of this circular disc 1 is arranged a. On this piezo-ceramic circular disc with the front and rear electrodes 2 , another circular disc 3 is attached, for. B. by gluing, welding, pressing or by other mechanical connecting means. If the electrodes 2 on the front and back of the ceramic circular disk 1 a are excited with an alternating voltage, then this piezo ceramic circular disk vibrates and executes bending vibrations, the excitation preferably taking place at the resonant frequency with the circular disk 1 a. As a result, the circular disk 3 fastened thereon also swings, the surface of this circular disk 3 forming the one bearing surface of a bearing (not shown in more detail).

Fig. 1b shows that on the top of the circular disc, the z. B. plastic, metal or other material, air guide grooves, in this case spiral grooves 15 are incorporated, which are essentially microfine. The depth of such a spiral groove 15 is approximately a few micrometers, and it will be explained later that the shape and the length and the orientation of the spiral grooves 15 can vary within wide limits. In the exemplary embodiment shown, the spiral groove 15 extends spirally inward approximately from the outer circumference 20 of the circular disk 3 to an indicated central region 17 . When the opposite rotor rotates on the bearing surface, an air flow in the direction of arrow 16 is generated, starting from the outer circumference 20 , so that the air in the spiral grooves 15 moves radially inwards in the direction of the region 17 . Due to the radially inward spiral grooves, an area of increased pressure is thus formed in the central area 17 , so that the bearing in this area is particularly load-bearing and can absorb particularly high loads.

The B. Fig. 2a and 2b show that the piezoelectric bearing 1 can be operated in a first vibration mode, where it is seen that the circular plate 3 not shown in detail, fixed supporting elements 10 vibrates the z on the associated bearing points 5 (. a bearing plate) are arranged. The circular disk alternately assumes the schematically indicated positions 3 ', 3 ". According to FIG. 2b, an outer circumferential knot line 4 results, in the area of which the circular disk 3 rests while the circular disk oscillates in the middle area. This results in between rotating rotor 6 and the oscillating circular plate 3, an air gap 18, which is particularly high load bearing is because rhythmically compressed due to the resonance vibration of the support disc of the air space in the air gap 18 and decompressed. at the same time generate the spiral grooves 15 on the circular plate 3, an additional air cushion and lead to a strengthening of the carrying properties, in particular in the central region of the circular disc 3. Even if the circular disc 3 no longer vibrates, the bearing set in rotation with the spiral grooves 15 is sufficient for the central region 17 to carry the bearing alone.

FIGS. 3a and 3b show a different vibration mode of the circular plate 3, which in turn oscillates between the support elements 10, wherein a second-order vibration is provided. Also shown are the spiral grooves, which cause a corresponding increase in the bearing capacity in the central area. Because of the vibration mode according to FIG. 3a, double, concentric knot lines are thus effected, the bearing not moving in the area of these knot lines 7 , while stable vibrations with compression and decompression of the air space in between are effected outside these knot lines.

FIG. 4 shows another embodiment of the air-guiding grooves, which in this example are curved in the shape of a hook. These are the grooves 15 d, which extend approximately in the shape of a herringbone pattern radially inwards from the outer circumference 20 of the disk 3 , are then curved along a circumferential line (region 23 ) and continue there with a different curvature directed radially inwards. These herringbone grooves 15 d have the advantage that the air is sucked in both radially inward in the direction of arrow 21 from the outer circumference to the region 23 but at the same time air is sucked in via a central recess 19 and is introduced radially outwards into the region 23 in accordance with the direction of the arrow 22 . The two air flows in the arrow directions 21 , 22 thus meet in the area 23 and form a concentric very strong bearing area there.

FIG. 5 shows a four quadrant representation of various embodiments of different shapes of air-conducting grooves 15 a, 15 b, 15 c.

The upper right quadrant shows that the grooves 15 d can be arranged in a herringbone pattern, as shown in FIG. 4 and which was explained in more detail there. The herringbone-shaped grooves 15 d do not necessarily have to meet in the region 23 , but they can also meet there offset from one another. It is important in this exemplary embodiment that the air flows both radially outward from the recess 19 in the direction of arrow 22 and also flows radially inward in the direction of arrow 21 from the outer circumference.

In the upper left quadrant of FIG. 5 it is shown that such spiral grooves 15 b can also only extend from the outer circumference to approximately the middle, but that no further spiral grooves are present starting from the center towards the central recess 19 . This embodiment has the advantage that a particularly high bearing pressure is built up in this central region, free of spiral grooves, because the bearing air is supplied in this region.

In the lower left quadrant of FIG. 5 it is shown that the spiral grooves 15 run continuously inwards from the outside, as has already been described in connection with FIG. 1b.

. The lower right quadrant of Figure 5 shows that it can be provided directly radially inward and the recess nearest 19 spiral groove 15 located to arrange c, so that in the area free of spiral grooves - that is, radially outward as viewed in the direction of the outer periphery - forms an area of increased bearing pressure.

FIGS. 6 and 7 show different shapes of electrodes forming the bending vibration excitation of the piezo disc 1 a. According to FIG. 6 a, the ceramic circular disk 1 a is not designed as a solid disk, as shown in FIG. 1 a, but is designed as an annular disk and has a central recess 13 . In connection with FIG. 6b it is shown that the electrodes on this ring disk can be arranged in a sector-like manner, namely in the form of electrode segments 12 which define intermediate regions 11 between them which are not occupied by electrodes.

Fig. 7b shows that even annular electrodes 12 a, 12 b can be present, which between them form annular gaps 24, which are occupied or not penetrated by the electrode surfaces.

It is also shown that a recess 19 may or may not be present in this embodiment.

It is important that in all the arrangements described above - irrespective of the type and configuration of the electrodes - the a with the piezo disc 1 a circular disc 3 connected with the novel spiral groove or grooves 15 is provided 15 d.

In another embodiment of the invention, it is provided that this circular disc is formed flat entirely through 3 in your bearing surface 59 and the opposite bearing surface, that is, the bearing surface on the rotating part, the inventive spiral grooves 15 a- have b 15th

In the arrangement of electrode segments 12 according to FIG. 6b, node lines 14 according to FIG. 7a then result on the circular disk 3 .

Figs. 8 to 12 now show embodiments of radial bearings, which can be realized both alone and in combination with the above-described thrust bearings of Figs. 1 to 7.

Fig. 8a shows generally a piezo-electrically excited radial bearing comprising a piezo-tube 25, which consists of a ceramic material or of a plastic material and is internally and externally covered with associated electrodes 26. On the outer circumference of this piezo tube 25 , a tube 27 is placed, which corresponds in function to the aforementioned circular disk 3 . An external radial bearing is provided, ie the entire bearing arrangement is overlapped from the outside by a rotor wall 28 of a rotating rotor 6 , so that the bearing air gap 29 is generated between the inside of the rotor wall 28 and the outside of the tube 27 . Spiral grooves 9 are again provided on the surface of the tube 27 , it being irrelevant, as already indicated, whether these spiral grooves are arranged on the outer circumference of the tube 27 or on the inner circumference of the rotor wall 28 . However, both of the parts mentioned can also have the spiral grooves 9 mentioned.

This radial piezo-electrically excited bearing can in turn operate in two different vibration modes, as shown in FIGS. 9 and 10. It is shown schematically that on a central support 31 radially outward vibration nodes 30 are formed, on which the tube 27 oscillates stably between two positions 27 ', 27 ".

If the oscillator is operated in its second oscillation mode, then a double oscillation according to FIG. 10 is generated.

FIG. 8c shows an outer, rotating rotor 6, which forms one part of the bearing with its rotor wall 28, while the fixed bearing is formed by the inner part of the piezo tube 25. The bearing clearance is supplied in the axial direction in the direction of arrows 34 and 35 from above and below, and the spiral grooves 9 lead this bearing clearance to a stable, central, axial area along the length of this piezo tube 25 . The spiral grooves are incorporated into the material wall 33 on the outer circumference of the tube 27 . The middle area is thus marked at position 37 , as is also shown in FIG. 11a.

Fig. 11a shows an internal arrangement of a spinning rotor 6, wherein the piezoelectric tube is provided with external and internal electrodes 26 and 25 is applied to the outer periphery of a further tube 27 which acts as a flexural vibrator. The exemplary embodiment shown now shows that the rotor 6 runs within the tube 27 and is covered on its outer circumference with the spiral grooves 9 according to the invention, the spiral grooves being straight or only slightly curved from the outer circumference of the rotor 6 in the direction of a central, central one Move the area on the longitudinal center axis of the rotor 6 . This creates a central area 8 , which is supplied with storage air in a particularly stable manner and which therefore has particularly superior wearing properties.

Another embodiment is shown in FIG. 11 b, in which the bearing air for the region 8 is not brought in from the bearing air gap 29 itself, but is brought in via additional radial feed bores 49 . It is only shown schematically that such radial feed bores 49 can be present in an external support sleeve 48 . This support sleeve 48 can, however, also be omitted and only the radial piezo bearing 50 can still be present, as is shown in FIG. 11b. The air is supplied in the direction of the arrow 51 in a radially inward direction via the supply bores 49 , flows into the air gap 29 and is distributed there in the direction of the arrows 52 , 53 upwards and downwards. The pressure distribution 54 is shown schematically on the right-hand side of FIG. 11b, the maximum bearing pressure being reached in the outer regions 56 and a relatively low pressure being present in the central region 55 .

The Fig. 12 show different possible electrode assembly of such a radial bearing.

It can be seen from FIG. 12a in connection with 12b that the electrodes can be designed as segment electrodes 32 , which are arranged in segments on the inner circumference of the piezo tube 25 . On the other hand, a continuous electrode 26 encompassing the full circumference of the jacket can be arranged on the outer circumference.

Deviating from this illustration, according to FIG. 12d, there may be circumferential, closed ring electrodes 38 which are axially spaced from one another and which are separated from one another in the axial direction by associated ring gaps 39 . Again, the counterelectrode 26 can again be arranged on the entire circumference of the tube 25 .

When a piezoelectric bending vibrator of this type is excited, a node distribution according to FIG. 12c results. That is, Starting from a stationary, stable support 31 , oscillation nodes 30 are formed, on which the entire tube 27 oscillates stably between its positions 27 ', 27 ". On the outer circumference of this tube 27 , one half of the bearing is then arranged, which is opposed by a rotor with its bearing surface The spiral grooves 9 described above can either be arranged on the outer circumference of the tube 27 or on the inner circumference of the rotor, as will be explained below.

Fig. 13a shows a first embodiment of a rotor 6 which is supported under pretension by means of a magnetic axial piezoelectric / air bearing, while it is held in the radial direction by a magnetic bearing. The radial magnetic bearing essentially consists of pole shoes 42 which are distributed uniformly around the circumference, as shown in FIG. 13b, and which are each acted upon by a winding 43 , 44 . The rotor 6 is permanently magnetic. It rotates in the direction of arrow 41 . The piezo bearing 1 described in the previously described exemplary embodiments is used to form the axial bearing, which in turn comprises a circular disk 3 which, together with the rotor 6, forms an air gap 18 which carries the rotor 6 in the axial direction.

In a first embodiment it is provided that no grooves or spiral grooves are formed on the circular disk 3 , but that this bearing works without spiral grooves, because a corresponding magnetic bias is given in the axial direction by a magnet 45 . This is because there is the advantage that a further bearing opposite the lower piezo bearing 1 can be omitted in the axial direction because the bearing is biased downwards in the axial direction by the magnet 45 . The magnet 45 rests on a stationary support plate 46 , and the circular disk 3 is supported on stable areas 8 which extend approximately in a ring shape and at whose support points the vibration nodes are formed.

In another embodiment it is provided that the circular disc 3 is additionally provided with the spiral grooves described above, so that this bearing receives even better wearing properties, because according to this embodiment it consists of a combination of a piezo-electrically excited bearing with an air bearing with spiral grooves . As stated, the radial bearing component is formed by a magnetic bearing consisting of the pole shoes 42 and the windings 43 , 44 .

In the exemplary embodiment according to FIG. 14 it is shown that a radial bearing can be designed in the same way as it is shown with reference to the previously described axial bearing according to FIG. 13a.

When designing a radial piezo bearing 50, it is again important, as described above, that the tube 27 vibrates stably in the air gap 29 , the tube being held stable by the described support elements 8 . The support elements 8 thus symbolize the stable guide knot for holding this tube.

The axial bearing component is formed by two pole shoes 42 lying axially opposite one another, which are provided with corresponding windings 43 , 44 .

Fig. 15 shows as a further embodiment, the combination of a radial bearing 50 having an axial piezo piezo bearing 1, as described with reference to the foregoing embodiments. Both the axial piezo bearing 1 and the radial piezo bearing 50 can be provided with the spiral grooves mentioned above. The spiral grooves can also be arranged on only one of the bearings. It is also irrelevant whether the spiral grooves are now arranged on the fixed part or on the circumferential part. A magnet 45 in turn serves as an additional axial bearing preload.

A method for operating such a bearing now provides, as shown in FIG. 16, that starting from the starting point 60, the bearing pressure is first applied by the piezo-electric loading of the bearing in accordance with the load capacity curve 57 . This means that the bearing pressure, which is plotted on the ordinate, increases in the curve branch 57 a from position 60 in the direction of arrow 61 , the bearing capacity being initially applied only by the piezoelectric bearing component. With increasing speed, e.g. B. after a start-up time of 0.5 sec, the air bearing also begins to act starting from position 62 , the air bearing pressure increasing according to curve branch 58 a. By superimposing both bearing components according to curves 57 a, 58 a, an improved and increased bearing pressure is already achieved in the start-up area.

As soon as the supporting force curve 57 of the piezo bearing has reached its maximum, also the supporting force curve is increased as far as the air bearing 58, that the piezoelectric bearing can be turned off, as the descending branch 57 b of the curve 57 indicates. The bearing force is then applied solely by the air bearing. The piezoelectric bearing is therefore preferably only operated between positions 60 and 63 , ie in the start-up area, while the air bearing or the air bearing component is operated from position 62 over the entire on-time or running time of the air bearing.

This results in the advantage that the start-up can be carried out with much less friction, because essentially the piezo-electric bearing component acts in the start-up from positions 60 to 62 , while the air bearing component acts in the area outside this start-up area.

Such a bearing has superior carrying properties, an extended one Lifetime, better dynamic stability, better tipping behavior and improved stiffness and damping.  

Drawing legend

1

Piezo bearing (axial)

2nd

circular electrode

3rd

Circular disc

3rd

',

3rd

"

4th

Knot line

5

Depository

6

rotor

7

Knot line

8th

Area

9

Spiral groove

10th

Support element

11

Intermediate area

12th

Electrode segment

12th

a,

12th

b

13

Recess

14

Knot line

15

Air guide groove a, b, c, d (spiral groove)

16

Arrow direction

16

'

17th

Area

18th

Air gap

19th

Recess

20th

Outer circumference

21

Arrow direction

22

Arrow direction

23

Area

24th

Annular gap

25th

Piezo tube

26

Electrodes

27

Pipe,

27

',

27

"

28

Rotor wall

29

Bearing air gap

30th

Vibration node

31

carrier

32

Segment electrode

33

Material wall

34

Arrow direction

35

Arrow direction

36

37

position

38

Ring electrode

39

Annular gap

40

. Magnetic bearings

41

Arrow direction

42

Pole piece

43

Winding

44

Winding

45

magnet

46

Support plate

47

Annular gap

48

Support sleeve

49

Feed hole

50

Piezo bearing (radial)

51

Arrow direction

52

Arrow direction

53

Arrow direction

54

Pressure distribution

55

Middle area

56

Outdoor area

57

Load curve (piezo bearing)

57

a,

57

b

58

Load curve (air bearing)

58

a,

58

b

59

storage area

60

Contact point

61

Arrow direction

62

position

63

position

Claims (16)

1. Bearing arrangement, characterized by a combination of a squeeze film bearing with an air bearing. 2. Bearing arrangement according to claim 1, characterized in that a bearing half is designed as a vibrating surface ( 3 ) which is excited by an oscillation mechanism, an air gap ( 18 ) formed from compressed air between the bearing halves, which absorbs the bearing forces. 3. Bearing arrangement according to claim 1 or 2, characterized in that on the tread at least one bearing half air guide grooves ( 15 a- 15 d) are provided, which cause an additional pressure build-up in the air gap ( 18 ). 4. Bearing arrangement according to one of claims 1 to 3, characterized in that the air guide grooves ( 15 a- 15 d) are designed as spiral grooves. 5. Bearing arrangement according to one of claims 1 to 4, characterized in that the air guide grooves ( 15 a- 15 d) are designed as hook-shaped or V-shaped grooves. 6. Bearing arrangement according to one of claims 1 to 5, characterized in that the air guide grooves ( 15 a- 15 d) are formed on the fixed bearing surface. 7. Bearing arrangement according to one of claims 1 to 6, characterized in that the air guide grooves ( 15 a- 15 d) are formed on the movable bearing surface. 8. Bearing arrangement according to one of claims 1 to 7, characterized in that it is designed as an axial bearing ( 1 ). 9. Bearing arrangement according to one of claims 1 to 7, characterized in that it is designed as a radial bearing ( 50 ). 10. Bearing arrangement according to one of claims 1 to 9, characterized in that they are designed as a combination of a thrust bearing with a radial bearing is. 11. Bearing arrangement, characterized by a squeeze film bearing magnetic bias. 12. Bearing arrangement according to claim 11, characterized in that the magnetic bias only on one side of the rotating part is arranged. 13. Bearing arrangement according to claim 11 or 12, characterized in that a bearing half is designed as an oscillating surface which is excited by an oscillation mechanism, an air gap ( 18 ) formed from compressed air between the bearing halves, which absorbs the bearing forces. 14. Bearing arrangement according to one of claims 11 to 13, characterized in that at least one half of the bearing air guide grooves ( 15 a- 15 d) are provided on the tread, which cause an additional pressure build-up in the air gap ( 18 ). 15. A method for operating the bearing arrangement according to claims 1 to 14, characterized in that when the camp starts up, the squeeze  Film camp takes effect through appropriate external stimulation and at The air bearing becomes effective when a predetermined starting speed is reached. 16. The method according to claim 15, characterized in that the excitation for the squeeze film bearing after reaching the specified starting speed is switched off.